i

INTRAOPERATIVE HEMODYNAMIC PERFORMANCE AND

TRANSESOPHAGEAL ECHOCARDIOGRAPHIC (TEE)

CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE

PROSTHESIS (CHVP) IMPLANTED AT AORTIC POSITION

THESIS PROJECT

BY

DR. M. S. SARAVANA BABU

DM CARDIOTHORACIC AND VASCULAR ANAESTHESIA

2014 – 2016

DEPARTMENT OF ANAESTHESIOLOGY

SREE CHITRA TIRUNAL INSTITUTE FOR MEDICAL

SCIENCES AND TECHNOLOGY, TRIVANDRUM,

KERALA,

INDIA – 695011

ii

DECLARATION

I hereby declare that this thesis entitled, “INTRAOPERATIVE HEMODYNAMIC

PERFORMANCE AND TRANSESOPHAGEAL ECHOCARDIOGRAPHIC (TEE)

CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE PROSTHESIS

(CHVP) IMPLANTED AT AORTIC POSITION” has been prepared by me under the capable

supervision and guidance of

Dr. Rupa Sreedhar,

Professor and Head,

Division of Cardiothoracic and Vascular Anesthesiology,

Department of Anesthesiology,

Sree Chitra Tirunal Institute for Medical Sciences & Technology, Thiruvananthapuram, Kerala.

Place: Thiruvananthapuram

Date: 29.09.2016

Dr. M. S. Saravana Babu

DM Cardiothoracic and Vascular

Anesthesiology Resident,

Department of Anesthesiology,

SCTIMST, Thiruvananthapuram.

iii

CERTIFICATE

This is to certify that this thesis entitled, “INTRAOPERATIVE

HEMODYNAMIC PERFORMANCE AND TRANSESOPHAGEAL

ECHOCARDIOGRAPHIC (TEE) CHARACTERISTICS EVALUATION OF CHITRA

HEART VALVE PROSTHESIS (CHVP) IMPLANTED AT AORTIC POSITION” has

been prepared by Dr. M. S. SARAVANA BABU, DM Cardiothoracic and Vascular

Anesthesiology Resident, Division of Cardiothoracic and Vascular Anesthesiology, at Sree

Chitra Tirunal Institute for Medical Sciences & Technology, Thiruvananthapuram. He has shown

keen interest in preparing this project.

(GUIDE)

Dr. Rupa Sreedhar, MD, DNBE, PDCC

Professor of Anesthesiology, SCTIMST, Thiruvananthapuram

(COGUIDE)

Dr. Shrinivas V. Gadhinglajkar, MD, PDCC

Professor of Anesthesiology, SCTIMST, Thiruvananthapuram

(COGUIDE)

Dr. Prasanta Kumar Dash, MD, PDCC

Professor of Anesthesiology, SCTIMST, Thiruvananthapuram

iv

(COGUIDE)

Dr. Vivek V. Pillai, MS, MCh, Additional Professor of CVTS,

SCTIMST, Thiruvananthapuram.

(COGUIDE)

Dr. Vargheese T. Panicker, MS, MCh, Additional Professor of CVTS,

SCTIMST, Thiruvananthapuram.

v

CERTIFICATE

This is to certify that this thesis entitled, “INTRAOPERATIVE HEMODYNAMIC

PERFORMANCE AND TRANSESOPHAGEAL ECHOCARDIOGRAPHIC (TEE)

CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE PROSTHESIS

(CHVP) IMPLANTED AT AORTIC POSITION” has been prepared by

Dr. M. S. SARAVANA BABU, DM Cardiothoracic and Vascular Anesthesiology Resident,

Division of Cardiothoracic and Vascular Anesthesiology, at Sree Chitra Tirunal Institute for

Medical Sciences & Technology, Thiruvananthapuram. He has shown keen interest in preparing

this project.

Place: Thiruvananthapuram Dr. Rupa Sreedhar,

Date: 29.09.2016 Professor and Head,

Division of Cardiothoracic and Vascular Anesthesiology,

Department of Anesthesiology, SCTIMST,

Thiruvananthapuram.

vi

ACKNOWLEDGEMENT

I would like to express my gratitude to all those who have contributed towards the

completion of this thesis.

First and foremost, I offer my sincere acknowledgement and gratitude to

Professor, Dr. Rupa Sreedhar, my chief guide and Head of the Division of Cardiothoracic

and Vascular Anesthesia, who created a congenial atmosphere at the workplace to enable

me to complete this thesis by providing me all the requisite infrastructure of the Institute.

Needless to say, she continues to be a source of strength for all the residents in the

Department, each and every one of whom cherishes her motherly care.

I would like to express my deep sense of gratitude to Dr. Shrinivas V.

Gadhinglajkar, my co-guide in this endeavor; he was instrumental in framing the idea of

the project, he inspired and supported me during the study, and tirelessly guided me

throughout the course of this herculean effort. A clinician par excellence, he never fails to

inspire anybody who is privileged to be associated with him. He has been a true pillar of

support during my DM course and has been my mentor over the past three years. I am

truly honored to have him as my co-guide.

I would also like to acknowledge the guidance and support of my co-guides in this

project Dr. Prasanta Kumar Dash, Dr. Vivek V. Pillai and Dr. Vargheese T. Panicker.

I am also deeply indebted to my teachers, Dr. Thomas Koshy, Dr. Unni Krishnan

and Dr. Suneel who constantly supported and encouraged me during the past 3 years. I

am grateful to Dr. Subin Sukesan for his constant help, support and encouragement

throughout the duration of my course.

vii

I am thankful to my fellow residents Dr. Neelam Aggarwal, Dr. Deepak Mathew

Gregory, Dr. Keerthi Chigurupati, Dr. Lovhale Pravin Shriram and Dr. Rajesh for their

constant help and support throughout the study. My senior colleagues Dr. Uvaraj and Dr.

Jagadeesh deserves special mention for their support and guidance.

I would be failing in my duty if I do not acknowledge my deep gratitude to my

junior colleagues, Dr. Muthu Kumar, Dr. Balaji, Dr. Indranil Biswas, Dr. Kirubanand,

Dr. Kappian and Dr. Manjusha Pillai for their invaluable efforts in bringing out this

study.

My gratitude and sincere thanks to all the patients who willingly agreed to be a

part of the study.

I express my heartiest gratitude and sincere regards to my parents and family for

their support and encouragement throughout my educational career.

Last, but not the least, I would like to thank the Almighty God for giving me the wisdom

and health to make this thesis a reality.

Place: Thiruvananthapuram Dr. M.S. Saravana Babu Date: 29.09.2016

viii

DEDICATION

My humble effort I dedicate to my loving mother & father,

Dear mom and dad,

Many things have changed in my life over time, but your constant love, support

and encouragement has never failed me. Thank you for backing my every decision,

Thanks for being there always………….

Along with all hard working and respected

TEACHERS.

ix

CONTENTS

Sl. No Topic Page No

1 Introduction 1

2 Review of Literature 7

3 Aims and Objectives 29

4 Materials and Methods 32

5 Results and Observations 39

6 Discussion 58

7 Limitation of the study 69

8 Conclusion 71

9 Bibliography 74

Annexures

A List of abbreviations 86

B Consent form 88

C Observation chart 95

D TAC approval 99

E IEC approval 100

F Plagiarism originality report 102

G Master Chart 103

1

INTRODUCTION

2

INTRODUCTION

The history of Chitra heart valve prosthesis (CHVP) started with an ardent clinical

and social necessity in India, where the incidence of rheumatic fever and rheumatic heart disease

were high among the young population. In early 1970’s, nearly 2-2.5 million patients were

suffering from rheumatic heart disease in India. This was the foremost reason for the structural

damage of the heart valves resulting in heart failure and death. For many years, India relied on

imports of costly artificial valves to meet the national need. But many poor families in India

could not afford even the profoundly discounted price of imported artificial valves. To address

this domestic health challenge, search for an affordable, high quality, indigenous artificial heart

valve to meet international standards was commenced in 1976 by Dr. M.S. Valiathan through a

project funded by the Ministry of Science and Technology.

The mechanical heart valve must resist the stress of opening and closing some

forty million times a year. The raw materials used for manufacturing the valve should be bio-

compatible. In open position, blood should flow through the valve smoothly without any

turbulence or shear and tear to the valve leaflets. When closed, the regurgitation of blood should

be minimal. Design related features and drawbacks of mechanical heart valves which are most

commonly implanted in patients with valvular heart disease1 are portrayed in Table 1.

3

Table1:- Characteristics and drawbacks of different valve types1

VALVE TYPE

CHARACTERISTICS

DRAWBACKS

Caged ball valve

Time tested

Structurally complete built-in

redundancy in the strut design

Low levels of regurgitation in

the closed stage.

Comparatively large valve

height

Flow separation at

downstream of the valve,

may lead to thrombus

formation

Tilting

disc valve

Better hemodynamic features

than the caged ball valve

design

Lower height and hence

appropriate for all anatomical

sites

Large number of tilting disc

valves have been implanted till

date

The redundancy in the

cage strut structure is low

Low flow across the

minor orifice can lead to

tissue over growth and

thrombosis

Strut fracture and other

related complications

Bileaflet valve

Flow profiles across the

orifices are uniform

Low structural problems

Hinge design is

susceptible to

thrombus formation and

valve dysfunction

Escapement of leaflets

was reported in some

models

TTK Chitra heart valve prosthesis (CHVP) is a homegrown tilting disc artificial

heart valve designed and developed by Sree Chitra Tirunal Institute for Medical Sciences and

Technology (SCTIMST), India which was subjected to repetitive testing for improvising the

design. It has almost more than 90,000 implantations to date across the globe. On the whole

about 250 health centers and more than 300 surgeons were using the CHVP as of 2015 statistics.

Many patients with valvular heart diseases have been benefited after implantation of CHVP.

4

Chitra heart valve prosthesis has three main components (Figure 1)

1. Frame

2. Disc

3. Sewing ring

Figure 1:- Chitra heart valve prosthesis (CHVP)

Chitra heart valve prosthesis is routinely implanted in many hospitals all over the

globe. It is a single leaflet tilting-disc valve with an annular metallic stent, which is stitched to

the innate valve annulus with a sewing ring. The circular disc acts as an occluder, which is

suspended from the annular metallic ring by a single strut. The disc gets attached to the strut

eccentrically in such a way that the back pressure on the larger portion of the disc will tend to

close the valve. The disc occluder hinges open at 60 to 75 degrees. The eccentric location of the

5

disc produces two openings of different size and shape; a major orifice and a minor orifice

(Figure 1). The valve has an intricate flow pattern, wherein 70% of flow goes through the major

orifice and the remaining 30% passes through the minor orifice. This complex flow generates

resistance to forward flow and a larger zone of stagnation on the downstream surface of the disc.

Transesophageal echocardiography (TEE) is a valuable monitoring device during

cardiac surgery2. Studies have reported that TEE assessment of the prosthetic valve after

weaning the patient from cardiopulmonary bypass (CPB) has guided surgeons on many

occasions to alter the course of surgery3. Since TEE is now being used as a routine during valve

surgeries, cardiac surgeons depend on the post-CPB TEE observations to take surgical decisions

on the operation table. So it has become necessary for a perioperative physician to get well

acquainted with the normal echo-characteristics of the CHVP. However, till date there are no

intraoperative studies depicting the echocardiographic characteristics and hemodynamic flow

profile of the CHVP at aortic position.

Major complications associated with prosthetic valve implantation are prosthetic

valve regurgitation, stenosis and patient- prosthesis mismatch (PPM) 4

. This should be detected

and addressed as early as possible for preventing hemodynamic worsening5. Post-CPB period is

the most suitable time to deal with these complications.

However, the Doppler features of prosthetic valve observed in the post-CPB

period may not be similar to those noted in the postoperative follow up. This is because the

Doppler assessment is influenced by multiple factors in the intraoperative period including use of

inotropes, changing preload conditions, CPB-induced myocardial edema and inadequate

myocardial preservation.

6

Even though numerous studies have proven the long-term safety and efficacy of

CHVP implanted at aortic position6-8

, none of them had defined its normal intra-operative TEE

characteristics in the immediate post-CPB period, which are necessary in making important

intraoperative surgical decisions. Therefore, we conducted this study to evaluate the

intraoperative TEE characteristics of CHVP implanted at aortic position and also to assess the

utility of TEE in prediction of PPM in the perioperative period.

7

REVIEW OF LITERATURE

8

REVIEW OF LITERATURE

Degenerative and rheumatic disease remain the most common etiological factors

for the significant aortic valvular lesions. The treatment modalities include valve repair or

replacement. Although repair techniques for mitral and tricuspid valvular lesions are well

established, aortic valve repairs are still in the emerging phase. So valve replacement with a

mechanical valve or a bio-prosthesis is the most common choice for many patients suffering

from aortic valve disease. The diagnosis of prosthetic valve dysfunction may be difficult at times

because their presenting features are non-specific and mimic other cardiac pathologies such as

ventricular failure, pulmonary artery hypertension or other valvular diseases. So various imaging

modalities are always necessary along with clinical examination to confirm the prosthetic valve

dysfunction. In addition, the detection of prosthetic valve dysfunction may be confounded by

their variable intrinsic properties depending upon their design and type. For example, central

trivial regurgitation is a regular feature in stented bio-prosthetic and Medtronic-Hall tilting disc

valves unlike the bileaflet mechanical valves. The pressure drop across the valve orifices varies

among the bileaflet, tilting-disc and bio-prosthetic valve. Among the imaging modalities such as

cine-fluoroscopy, computed tomography and magnetic resonance imaging, the two dimensional

(2D) echocardiographic Doppler evaluation is the method of choice for the non-invasive

evaluation of the prosthetic valve function9.

Two dimensional transthoracic and TTE are the most common echocardiographic

imaging modalities used for the assessment of prosthetic valve function10

. Although transthoracic

echocardiography (TTE) is non-invasive and easy to perform, it has many limitations including

poor image quality due to thoracic tissues shielding the heart, multiple artefacts, need for

9

multiple probe angulations and off axis views. Also TTE cannot be used in the perioperative

period to assess the prosthetic valve function, because the presence of pericardial drains and air

may degrade the image quality. Therefore, TEE being less invasive and being capable of

producing good quality images, has become a mandatory tool in the intraoperative period for the

assessment of mechanical valves in the aortic position.

TEE is indicated in all open-heart procedures performed for valvular heart

diseases2. Perioperative TEE plays a pivotal role in surgical decision making and to evaluate the

success of surgical repair11

. In our study, we define the utility of intraoperative TEE in

evaluating the function of CHVP implanted at aortic position. The intraoperative

echocardiographic characteristics and hemodynamic performance of CHVP was studied and the

values were compared with the echocardiographic parameters of other aortic mechanical heart

valves in common practise. The intraoperative echocardiographic Doppler parameters of CHVP

was also compared with the data obtained by the TTE in the postoperative period.

Doppler evaluation of prosthetic valves

Rosenhek et al 12

analyzed the normal Doppler echocardiographic data for the

aortic and mitral prosthetic valves available in the literature and provided a comprehensive

overview for accurate interpretation of Doppler parameters. In this study, they concluded that the

normal values for peak velocity, mean gradient and effective orifice area (EOA) across the aortic

and mitral valve prosthesis are attributed to their flow rates and require correlation with the valve

type and size. Therefore, the normal Doppler values for the prosthetic valves should be defined

based on the specific flow rate.

10

Published studies on CHVP

Kumar et al 13

did an evaluative study on the Doppler and hemodynamic

characteristics of CHVP implanted at aortic and mitral position during the follow up period. Out

of 547 patients, 238 patients were examined for Doppler evaluation of transvalvular gradients

and estimation of effective orifice area. For CHVP implanted in aortic position, the valve sizes

21 and 23 mm produced the mean gradients (in mm Hg) of 10±5 and 9±4, and EOAs (in cm2) of

1.5±0.5 and 1.8±0.3 respectively. In the mitral position, the valve sizes 25, 27 and 29 mm

produced the mean gradients (in mm Hg) of 5±3, 4±2 and 4±2, and effective orifice areas (in

cm2) of 2.8±0.8, 3.1±0.7 and 2.9±0.7 respectively. Their study gave a conclusion that TTK

CHVP is hemodynamically comparable with other mechanical heart valves and their

complication rates are similar.

Namboodiri et al 14

studied the Doppler parameters of CHVP in aortic position to

establish normal reference values for them. The peak gradient and mean gradients across the

valve ranged from 7.7 to 66 mm Hg, and from 3.6 to 37 mm Hg, respectively. The peak velocity

and the peak and mean gradients showed a negative correlation with the increase in valve size (r

= − 0.71, r = − 0.69, and r = − 0.68 respectively; p value < 0.001). A significant positive

correlation was seen between the EOA and the valve size (r = 0.81, p value < 0.001). DVI

showed a poor correlation with valve size (r = − 0.05, p value 0.73). The Doppler parameters

such as velocity and gradients were flow dependent and Doppler velocity index (DVI) was

relatively flow independent. The authors also found that the Doppler parameters of CHVP

measured in the study were comparable to other prosthetic aortic valves in common practise.

These Doppler parameters should act as reference for the prosthetic valve assessment in clinical

practice.

11

Namboodiri et al 15

, in another study described the Doppler echocardiographic

parameters of mitral CHVP in 40 patients. The study aim was to determine the normal Doppler

parameters of CHVP in mitral position and to assess whether the mitral valve area derived by

continuity equation (CE) and pressure half time were comparable. The valve sizes included in

the study were 25, 27 and 29 mm. They drew a conclusion that mitral CHVP is associated with

normal hemodynamic parameters and Doppler profile which are comparable with those of other

different mechanical valves in common use. Calculated valve areas by CE and pressure half time

methods were similar in all three groups of patients. Mitral valve area calculated by both of these

methods is smaller than that of the actual orifice area provided by the manufacturer of the

CHVP.

Doppler evaluation of prosthetic valves as recommended by ASE

Zoghbi et al5, 16

in their American society of Echocardiography recommended

guidelines describe the echocardiographic assessment of patients with prosthetic valves. The

recommendation states that almost all prosthetic valves are inherently mild stenotic in nature in

comparison with normally functioning native valves. The degree of obstruction is determined by

the size and type of the valve implanted. Therefore it would be necessary to distinguish the mild

inherent stenosis of the prosthesis from that of pathological stenosis and PPM. The pattern of

physiological regurgitation associated with the prosthetic valve also varies with the design of the

valve. TEE is strongly indicated for the evaluation of prosthetic valve function and detection of

any complications such as PPM and pathologic regurgitation. Apart from valve assessment, it

also focuses on the cardiac evaluation such as measurement of size of cardiac chambers, Left

ventricular (LV) wall thickness and mass, and evaluation of LV systolic and diastolic function.

Valves are imaged in multiple views. The principles of Doppler interrogation of the prosthetic

12

valves are similar to those used in evaluating native valve stenosis or regurgitation. In patients

with aortic prosthesis, measurements of the aortic root and ascending aorta are recommended

(Table 2)

Table 2: Essential parameters in the complete assessment of prosthetic valve function

as recommended by ASE5

Information Parameter

Clinical information

Valve replacement date

Size and type of the valve

Weight, height and body surface area

Symptoms and sings

heart rate and Blood pressure

2D Imaging

Leaflets motion or occluder mechanism

Leaflets calcification or abnormal echo densities on the

prosthesis components

Integrity and motion of the sewing ring

Doppler echocardiography

Contour of the velocity jet

Peak velocity and peak gradient

Mean gradient

Velocity time integral of the jet

DVI (LVOT VTI/ AVprosthesis VTI)

Effective orifice area

Presence, location and severity of valvular regurgitation

Other echocardiographic data Biventricular size, function, and hypertrophy

Left and right atrial size

Concomitant valvular lesions

Assessment of pulmonary artery pressure

Size of aortic root and ascending aorta

Previous postoperative

studies

Particularly helpful in suspected prosthetic valvular

dysfunction

13

EXAMINATION OF THE PROSTHETIC AORTIC VALVE IN THE

INTRAOPERATIVE PERIOD5

Echocardiographic imaging considerations

As per the recommendations by the ASE, echocardiographic imaging should

evaluate the valve seating, motion of leaflets, occluder mechanism, angle of opening and the

surrounding area. Sometimes it may be essential to magnify the real time images using zoom

mode to have a clear view. Manipulation of the imaging plane may be needed until the occluder

mechanism of a tilting disc valve is visualized. The tilting disc is indistinctly imaged due to

reverberations artifacts, whereas the leaflets of normal tissue valves show an unrestricted motion.

In case of aortic valve prosthesis, left ventricular outflow tract (LVOT) should be delineated well

for the measurement of LVOT diameter and EOA. A 10% error in the measurement of LVOT

diameter will produce 19% error in the EOA and cardiac output measurement 17

.

Doppler echocardiography of prosthetic aortic valve

A complete Doppler evaluation comprises of color Doppler, pulse wave Doppler

(PWD) and continuous wave (CWD) Doppler examination in multiple imaging views.

Manipulation of TEE probe may be necessary to align the Doppler beam at a minimal angulation

with the flow. Doppler examination of aortic valve prosthesis includes an estimation of peak

velocity, peak and mean pressure gradients, acceleration time (AT), acceleration time/ejection

time ratio (AT/ET), DVI, cardiac output and EOA. The simplified Bernoulli equation is utilized

in calculating the pressure gradients across the valves. The pressure gradients are flow-dependent

and are overestimated in presence of inotropes and high cardiac output states. For prosthetic

aortic valves, EOA is calculated using CE. Many studies have proven that EOA is a valuable

14

parameter for evaluation of prosthetic valves and it correlates well with the size of the

prosthesis18, 19

. However, estimation of EOA is influenced by the site of measurement of LVOT

diameter and the site of placement of sample volume for measuring the LVOT velocity time

integral (VTI). Bileaflet prosthetic heart valves show a pressure recovery phenomenon

characterized by a high velocity jet and pressure drop limited to the small central orifice. This

localized pressure drop is recovered once the flow from the two lateral orifices joins with the

central flow. Unlike the bileaflet prosthesis, the phenomenon of pressure drop and recovery is

not significantly observed in tilting disc valves due to the presence of relatively larger orifices.

Patient prosthetic mismatch (PPM) occurs in a normally functioning prosthetic valve when EOA

is inadequate with respect to the patient’s body surface area resulting in high velocity and

pressure gradients across the valve. PPM has been related to reduce the long term survival,

deterioration of functional class, poor regression of LV and acute cardiac events. To define

adequate patient prosthesis match, the indexed orifice area (IOA) should be more than or equal to

0.85 cm2/m

2 for aortic valve prosthesis

20. The other flow independent parameters that were used

to assess the aortic prosthetic valve function are contour of the velocity jet, AT, AT/ET and DVI.

Doppler measurements should be obtained in sinus rhythm at a sweep speed of 100 mm/sec over

1 to 5 cardiac cycles. For the calculation of DVI and EOA by CE, a double envelope

CWDwaveform is preferred over separate measurements of LVOT and prosthetic valve VTI

because the values are obtained from the same cardiac cycle and the chances of error are less21

.

Prosthetic aortic valve regurgitation

Prosthetic valve regurgitation jets may be physiological or pathological. The

physiologic regurgitation jets are usually mild and classified as: 1) Washing jets – seen where the

leaflets meet the strut at hinge points 2) Closing jet – jet originating at the site of contact between

15

the occluder and the annular metallic stent. Both are located inside the sewing ring and are

thought to prevent thrombi formation within the sewing ring and on the LV surface of the disc.

They are located within the sewing ring, usually of low velocity, homogeneous in color, less than

5 cm in length and regurgitant fraction will be < 15%. They vary depending on the type of

prosthesis. The pathological regurgitation jets can be intravalvular or paravalvular. The location

of paravalvular regurgitation is outside the sewing ring. Biological valves commonly have mild

degree of central regurgitation. The prevalence of paravalvular regurgitation jets ranges from 5 to

20 % immediately in the post-CPB period. Majority of them are benign in nature, are not

associated with hemodynamic instability and usually disappear after the administration of

protamine. The large central intravalvular jets are invariably pathological and originate due to

occluder mechanism malfunction attributed to different etiologies. Identification of exact

location and classification of the severity of pathological regurgitation jets requires multiplane

TEE imaging and Doppler evaluation. The integration of qualitative, quantitative and semi-

quantitative parameters should be used to assess and grade the severity of prosthetic valve

regurgitation (Table 3).

16

Table 3: Parameters for assessment of the severity of prosthetic aortic valve regurgitation5

ECHOCARDIOGRAPHIC PARAMETER

MILD AR

MODERATE AR

SEVERE AR

Prosthetic valve structure and motion

Biological or Mechanical

normal

Abnormal

Abnormal

LV size Normal mildly dilated Dilated

QUALITATIVE OR SEMI-QUANTITATIVE

DOPPLER PARAMETERS

AR Jet width to % LVOT diameter

AR jet density

AR Jet PHT (ms)

LVOT flow versus pulmonary blood flow

Flow reversal in the descending aorta during

diastole

≤ 25% 26 – 64% ≥ 65%

Faint Dense Very dense

> 500 200-500 < 200

Mild ↑ Intermediate Highly ↑

Absent or

early

diastolic

Intermediate holodiastolic

QUANTITATIVE DOPPLER PARAMETER

Regurgitant volume (ml/beat)

Regurgitant fraction (%)

< 30 ml 30 – 59 ml > 60 ml

< 30 % 30-50 % >50 %

Abbreviations: AR- Aortic regurgitation; PHT- Pressure half time; LVOT – Left ventricular

outflow tract

17

Prosthetic aortic valve stenosis

Prosthetic valve stenosis is usually detected during follow up period after the

surgery. Valve stenosis may occur due to thrombus, pannus formation or infective endocarditis.

Isolated prosthetic valve stenosis is rare in the intraoperative period. However, prosthetic valve

stenosis may sometimes be observed in the post-CPB period due to occluder malfunction

attributed to suture or tissue tag entrapment or structural manufacturing defects. TEE has become

an essential imaging modality for the intraoperative detection of prosthetic valve malfunction,

PPM and suboptimal surgical repair. Various factors such as mechanical ventilation, changing

loading conditions, inotropic and chronotropic medications and pacing of the heart may interfere

with the assessment of prosthetic valve function. Therefore, assessment of prosthetic valve

function in the perioperative period is a unique challenge for the echocardiographer. The

diagnosis of prosthetic valve stenosis should not be based on detection of high velocity and

pressure gradient because high flow rates or PPM may also produce significantly high velocity

flows. Conversely, false low gradients may occur in a patient with severe prosthetic valve

stenosis if there is a low cardiac output state. Therefore, the diagnosis and grading of prosthetic

valve stenosis should be made in an integrated and sequential way by analyzing various

echocardiographic parameters (Table 4) (Figure 2).

18

Table 4: Doppler parameters of prosthetic aortic valve function5

Doppler Parameter

Normal

Stenosis possible

Stenosis

significant

Peak velocity

< 3 m/s

3-4 m/s

> 4 m/s

Gradient mean

< 20 mm Hg

20 – 35 mm Hg

> 35 mm Hg

Doppler velocity index

≥ 0.3

0.29 – 0.25

< 0.25

Effective orifice area

>1.2 cm2

1.2 – 0.8 cm2

< 0.8 cm2

Acceleration time

<80 ms

80 – 100 ms

> 100 ms

Contour of velocity jet

early peaking,

triangular

Triangular to

intermediate

Symmetrical

rounded contour

19

Figure 2: Algorithm for evaluation of elevated peak prosthetic aortic jet velocity5

DVI ≥ 0.30 DVI 0.25 - 0.29 DVI< 0.25

Consider Prosthetic Aortic

valve stenosis with

1. Sub-valvular narrowing

2. Gradient underestimated

3. LVOT velocity improper

Normal Prosthetic

aortic valve

Prosthetic aortic

valve stenosis Improper

LVOT

velocity

Indexed orifice area

High flow

across valve

Patient Prosthesis

Mismatch

> 100 <100 > 100 <100

Jet Contour

AT

(ms)

))

PEAK VELOCITY OF PROSTHETIC AORTIC VALVE > 3 m/s

20

The prosthetic valves are assessed using TTE in the post-operative period.

However, the prosthesis is closely inspected with TEE during surgery. The intraoperative

Doppler measurement should serve as the reference guide for the evaluation of prosthesis during

the follow up studies.

Shapira et al 2studied the impact of post-CPB intraoperative TEE in valve

replacement surgeries. About 417 patient’s data, who underwent valve replacement surgeries

(bio-prosthetic or mechanical valves), was studied in a retrospective manner. About 501 heart

valves were inserted which included: 237 mitral, 221 aortic and 43 tricuspid. In 15 patients

(3.6%), post-CPB TEE has detected unanticipated pathologic findings and demanded immediate

surgical correction. The other findings picked up by post-CPB TEE were peri-valvular leak (8

patients), immobilized leaflets (4 patients), coronary ostia obstruction by aortic valve (2 patients)

and incompetent xenograft (1 patient). In 47 patients (11.3%), who were difficult to wean from

CPB, intraoperative TEE contributed to the evaluation of the problem and to its therapeutic

management. Prolonged removal of air under intraoperative TEE imaging was needed in 45

patients (10.8%). From the results, they came to a conclusion, that immediate post-CPB TEE has

an important diagnostic and therapeutic role in patients undergoing valve replacement surgeries

and it should be widely applied.

Qizilbash et al 22

had an updated review on the impact of perioperative TEE in

aortic valve replacement. They found that many studies have shown that intraoperative TEE has

made alterations in therapy from 10 % to more than 40%. Pre-CPB TEE can provide predictive

information, guide optimize hemodynamics and diagnose the prediction of PPM. Placement of

various CPB cannulae can be performed under the guidance of TEE. Post-CPB TEE verifies the

surgical repair and monitor the hemodynamics. The authors suggested that although according to

21

current guidelines TEE is a class IIa indication for aortic valve surgeries, it should be routinely

used in aortic valve replacements (AVR).

Daniel et al 23

did a retrospective study on 140 prosthetic valves implanted at

mitral (89), aortic (45) and tricuspid (6) positions in 116 patients using transthoracic and

transesophageal echocardiography. TEE was found to be consistently better than the TTE during

the evaluation of structural abnormalities of tissue valves in the mitral and aortic positions and

localization and quantification of prosthetic valve regurgitation. Six patients had left atrial or left

atrial appendage thrombus and it was detected only by TEE in 5 patients. The authors concluded

that TEE should be complimentary to TTE during the evaluation of patients with prosthetic valve

dysfunction or during the follow-up of older tissue valves.

Daniel et al 24

compared the transthoracic and transesophageal echocardiography

for detection of prosthetic and bio-prosthetic valve abnormalities in the mitral and aortic

positions. They studied 148 prosthetic valves in 126 patients by TTE and TEE for detection of

abnormalities. Prosthetic valve endocarditis and thrombi were diagnosed by TTE in 36% and

13% respectively. But TEE identified these lesions in 82% and 100% respectively. Overall, they

found that TTE had 57% sensitivity and 63% specificity, whereas TEE had 86% sensitivity and

88% specificity in detecting the prosthetic valve endocarditis, thrombi and other morphologic

abnormalities.

Alton et al25

studied the normal characteristics of 47 Starr-Edwards prosthetic

heart valve implanted in 37 patients using TEE. Using this data, they compared usefulness of

TEE with TTE in detecting the valve abnormalities. They found that TEE is superior to TTE in

detection of thrombus, severity of mitral regurgitation and vegetation and abscess formation in

infective endocarditis. They concluded that TEE has a unique efficacy in detection of prosthetic

22

valve dysfunction and it is also of great value in assessing the severity of prosthetic valve

regurgitation and response to treatment when TTE becomes inadequate.

Levy et al26

compared the Doppler profile in patients undergoing AVR between

post-CPB intraoperative TEE and post-operative TTE (after two to four months of surgery).

Thirty one patients were included in the study. The valves studied were Freestyle stentless aortic

root bio-prosthesis (23 patients), Medtronic-Hall tilting disc mechanical valve (4 patients),

mosaic bio-prosthesis (3 patients) and Carpentier Edwards Perimount pericardial valve (1

patient). On echocardiographic evaluation of these patients, they reported that there were no

significant differences in Doppler pressure gradients or LVEF among these patients at the two

time intervals as mentioned above. However, there was no obvious correlation in the Doppler

mean gradients at the two time periods (R2 = 0.09; p = 0.11); for peak gradient the correlation

was extremely weak but statistically significant (R2 = 0.17; p = 0.02). The prediction of high

mean gradient obtained on TTE during follow up period based on reference values provided by

intraoperative TEE was also poor (0.63-area under curve). They concluded that gradients

measured by intraoperative TEE do not correlate with those measured by TTE during the follow-

up period. The intraoperative TEE also has no utility in predicting a high mean gradient observed

2-4 months after the surgery.

The functioning of a prosthetic aortic valve in the intraoperative period is assessed

by TEE using M mode, 2 dimensional echo, color Doppler and spectral Doppler methods.

Assessment of flow across the prosthetic valve using spectral Doppler interrogation remains an

invaluable component of complete prosthetic valve examination.

23

Weinstein et al27

analyzed the M-mode, 2DE and Doppler characteristics of St.

Jude medical valves implanted at aortic and mitral position in 23 asymptomatic patients.

Findings were compared with the echocardiographic characteristics of native valves. The

outcome of the study suggested that the morphological spectra of mitral and Doppler flow were

analogous between the native and the prosthetic valves, unlike the values of the peak and mean

velocities, which were higher in prosthetic valves. M mode and 2D echocardiography were of no

value in quantitative estimation of prosthetic valve function. Color Doppler studies of prosthetic

valves demonstrated 4 cases of paravalvular leaks which were not identified by M mode or 2D

echo. The authors concluded that Doppler echocardiography is reliable and helpful in providing

quantitative data about the flow profiles across the St. Jude prosthetic valves and is valuable for

discovering the prosthetic valve dysfunction.

Different parameters ascertained on spectral Doppler interrogation of prosthetic

aortic valve include peak velocity, peak gradient, mean gradients, EOA, stroke volume, DVI and

AT. Studies differ in their conclusion regarding which Doppler parameter can provide precise

information on prosthetic valve function and which among them can be more pertinent in the

perioperative period.

Panidis et al28

performed Doppler echocardiography in 136 patients with

normally functioning prosthetic valves at aortic, mitral and tricuspid positions. The valves

studied include St. Jude (82), Bjork Shiley (18), Beall (13), Starr Edwards (7) and tissue valve

(16). The results showed that in aortic position, St. Jude valve had a lower peak velocity, lower

peak and mean gradient than other valves whereas in mitral position, the St. Jude valves

provided a larger EOA in comparison to other prosthetic valves. Insignificant regurgitation was

detected in all the implanted valves in both mitral and aortic position. They also included 17

24

patients with proven malfunctioning prosthetic valves in their study. The malfunctioning valves

consisted of St. Jude (4), Bjork-Shiley (2), Beall (4) and tissue valves (7). They found that

Doppler echocardiography correctly identified the malfunctioning valve in all patients, except 2

who had a Beall valve. They concluded that Doppler echocardiography is a useful technique for

the detection of prosthetic valve dysfunction and the St. Jude medical prosthesis appears to be

associated with ideal hemodynamic parameters and valve features compared to Bjork-Shiley and

other tissue valves.

Badano et al29

prospectively studied 76 consecutive patients implanted with

Bicarbon bileaflet prosthetic valves at mitral and aortic positions to describe the normal Doppler

flow characteristics of these valves and compared them with those obtained from St. Jude

medical valves. They did not find any significant difference in the trans-prosthetic gradients,

pressure half time and EOA among the valves implanted at mitral position. But in aortic valve

prosthesis, they observed a significant decrease in the transprosthetic gradients and increase in

the effective orifice areas as the size of the prosthetic valves increased. EOA estimated by

continuity equation was found to have statistically significant correlation with the sizes of the

prosthetic valves than the peak and mean gradients. Also the trans-prosthetic gradients and EOA

did not differ significantly between Bicarbon and St. Jude Medical prosthetic valves among

different sizes of aortic prosthetic valves.

Rajani et al30

in their updated review summarized the normal Doppler

echocardiographic parameters of mechanical valve, bio-prosthetic valve and homograft

implanted in aortic position. About 129 studies were reviewed and Doppler parameters such as

peak velocity, peak and mean pressure gradient and EOA calculated by CE were noted. They

found that in the order of degree of obstructive nature, caged-ball valve prosthesis occupied the

25

top-most position which was trailed by the stented porcine and single tilting-disc valves. The

stented bovine pericardial valves and intraannular bileaflet mechanical valves were slightly less

obstructive. Stentless valves and reduced-cuff bileaflet valves were similar and appeared less

obstructive than the valves mentioned above. Homo-grafts were found to be least obstructive.

They suggested that every study designed to evaluate the prosthetic valves should provide details

of peak velocity, peak and mean pressure gradients using the modified Bernoulli equation, and

also the EOA using the standard form of CE. If any new valve design is introduced, normal

echocardiographic ranges should be published as a reference guide to the clinicians. A baseline

echocardiogram should be done in every case as soon as the valve is implanted to create a

‘finger-print’ as a reference for future studies.

Chafizadeh et al 18

studied 67 patients receiving St. Jude Medical valves in aortic

position. The objective of the study was to evaluate the utility of CE for the noninvasive

assessment of prosthetic aortic valve function. The maximal gradients derived by the Doppler

ranged from 9 to 71 mm Hg. The continuity equation derived EOA of the prosthetic aortic valve

ranged between 0.73 cm2 and 4.23 cm

2 for 19-mm and 31-mm valves respectively and it

described the flow characteristics of various sizes of valves better than the gradients alone. The

mean DVI 0.41±0.09 and it was independent of the valve size. They came to a conclusion that

CE can be used for the assessment of prosthetic St. Jude valves implanted at aortic position. It

provides a better assessment than the use of gradients alone for the evaluation of prosthetic valve

function.

PPM is a frequent problem in patients undergoing aortic valve replacement when

the EOA of the implanted prosthetic valve is less than that of a native valve with respect to body

surface area (BSA). It produces hemodynamic consequences in the form of high trans-prosthetic

26

flow gradients in a normally functioning prosthetic valve. The severity of PPM is classified

based on indexed orifice area of the prosthetic valve with iEOA ≥ 0.85 cm2/m

2 as normal, 0.65-

0.85 cm2/m

2 as moderate PPM and < 0.65 cm

2/m

2 as severe PPM

31, 32. The presence of PPM has

a major short term as well long term impact on the hemodynamics, recovery from left ventricular

hypertrophy, functional capacity, morbidity and mortality.

Tasca et al33

studied the midterm impact of PPM on cardiac events and overall

mortality after aortic valve replacement. About 315 patients with isolated aortic stenosis were

studied consecutively and the indexed EOA for each size and type of prosthesis was calculated

after aortic valve replacement. Forty seven per cent of patients had PPM that correlated well with

cardiac events and overall mortality. Patients with PPM had significantly less overall survival

and cardiac-event free survival rates than those with no PPM. They concluded that PPM is an

independent predictor of midterm mortality and cardiac events in patients undergoing AVR It

can be avoided by taking preventive measures at the time of surgery.

Mohty et al 34

studied the impact of PPM on long-term survival in 388 patients

who underwent AVR with small (19 or 21 mm) St. Jude Medical prosthetic valves. They found

that patients with severe PPM (iEOA ≤ 0.60 cm2/m

2) had a significantly less 5-year and 8-year

survival rates than those moderate (iEOA 0.60 – 0.85 cm2/m

2) or no PPM (iEOA ≥ 0.60 cm

2/m

2).

Also the mortality rate and the incidence of congestive heart failure were higher in patients with

severe PPM compared to those with moderate or no PPM.

Mohty et al35

in another study evaluated the effect of PPM on late survival and the

survival modulation by age, body mass index (BMI) and pre-operative LV function. About 2,576

patients who underwent AVR were included in the study. They found that severe PPM increases

the late mortality only in patients < 70 yrs of age or BMI < 30 kg/m2 or an LV ejection fraction

27

(LVEF)< 50%. In patients with moderate PPM the late mortality was increased with poor LV

function whereas the prognosis was normal with preserved LV function.

Head et al36

performed a meta-analysis of observational studies to study the

impact of PPM on long-term survival after AVR. Thirty four studies were included comprising

27,186 patients and 133,141 patient-years. Analysis by severity of PPM demonstrated that both

moderate and severe PPM increased all-cause mortality and cardiac-related mortality. They

concluded that PPM is associated with an increase in all-cause and cardiac-related mortality over

long-term follow-up.

Pibarot et al37

did a study on 396 patients to predict the PPM at the time of

surgery using three indices, viz. indexed internal geometric area, valve size and projected

indexed orifice area. The results were compared with the Doppler derived mean gradients and

IOAafter surgery. Their results showed that PPM as well as resting and exercise postoperative

gradients can be accurately predicted by the projected indexed orifice area calculated at the time

of surgery.

The available options to avoid or reduce the severity of PPM during aortic valve

replacement include (1) Implanting an another type of prosthetic valve with larger EOA (2)

Aortic root enlargement and placing a larger valve (3) accepting PPM by consideration of other

clinical conditions

Ardal et al38

evaluatedthe long-term results of posterior aortic root enlargement

(ARE) in 124 patients who underwent AVR with ARE. The overall operative mortality was

6.4%. Late deaths were 5.4%. The predictors for late mortality were infective endocarditis and

low cardiac output syndrome. Permanent pacemaker was needed in 3.2% patients. They

28

concluded that posterior ARE has no additional risk and the long-term survival rates as well as

complication-free survival rates are acceptable.

Coutinho et al 39

analyzed the short-term outcome of ARE with adverse events

and death as end points. About 218 patients with small aortic root who underwent AVR with

ARE were compared with those with small aortic root with AVR alone. There was no much

significant difference in hospital mortality, need of inotropic support, chest tube drainage and

complication rates. The peak and mean pressure gradients were significantly lower in patients

with root enlargement. About 11% of patients who underwent ARE had moderate PPM but

severe PPM was not present in any of them. The authors suggested that ARE does not affect the

operative risk or short-term outcome and it can be done in a safe and reproducible manner.

The sensitivity and specificity of PPM detection by intraoperative TEE has not

been reported. If studies prove that PPM can be detected accurately by intraoperative TEE, then

the further decisions whether to accept the PPM or to perform ARE or to select appropriate size

and type of prosthesis can be taken on the operation table in the pre-CPB period. Also the

sensitivity and specificity of preoperative TEE in detecting PPM can be ascertained in a

retrospective manner in the post-CPB period by the calculating EOA using TEE.

29

AIMS AND OBJECTIVES

30

AIMS AND OBJECTIVES

Hypothesis

We hypothesize that:

1. AVR using CHVP provides satisfactory hemodynamic conditions after termination of CPB.

2. Examination of tilting disc CHVP with TEE in the post-CPB intraoperative period will reveal

echo characteristics and Doppler flow profile which are compliant with the criteria set by the

ASE to describe a normal functioning aortic valve prosthesis.

Aims and objectives

Our primary objectives were:

1. To analyze the intraoperative hemodynamic performance of CHVP at aortic position using

clinical parameters and TEE.

2. To define the intraoperative echocardiographic characteristics and flow profile of CHVP on

2D and color Doppler examination.

3. To study the intraoperative spectral Doppler parameters of CHVP.

4. To compare the intraoperative Doppler parameters among different sizes of CHVP.

Our secondary objectives were:

1. To compare the intraoperative TEE Doppler profile with postoperative TTE Doppler profile

performed 48 hours after surgery and 3 months after surgery

31

2. To compare the Doppler profile of CHVP in our study with the published data of St. Jude

Medical Bileaflet mechanical valve prosthesis in common use

3. To analyze the detection of PPM of CHVP by intraoperative TEE.

32

MATERIALS AND

METHODS

33

MATERIALS AND METHODS

After obtaining approval from the Technical Advisory Committee (TAC) [SCT-

/S/2014/311], Institutional Ethics Committee (IEC) [IEC registration no - ECR/189/Inst

/KL/2013], and after registering the trial in Clinical Trials Registry – India (CTRI)[Reg no -

CTRI/2016/08/007141] this prospective, observational study was carried out in a tertiary referral

Centre (SCTIMST) which annually performs more than 300 heart valve replacements.

Inclusion Criteria

Adult patients subjected to elective AVR using CHVP without repair or replacement of

other valves.

Exclusion Criteria

Patients < 18 years of age and > 60 years of age

LVEF< 40%

Mitral regurgitation – moderate-to-severe or severe

Mitral stenosis - moderate-to-severe or severe

After weaning from CPB in first attempt, patients requiring re-institution of CPB, due to

inadequate surgical results like severe prosthetic aortic valve regurgitation and inadequate

motion of occluder disc.

Concomitant repair or replacement of other valves

Patients having significant coronary artery disease with or without requirement for

coronary artery bypass grafting; atrial septal defect; ventricular septal defect; or any

34

significant pathology that would affect hemodynamic parameters and echocardiographic

profile of the prosthetic valve.

Re-do aortic valve replacement

Contraindication to TEE probe placement like esophageal strictures, esophageal varices,

esophageal tumors, gastric ulcer,previous esophageal surgery, esophageal diverticulum,

tracheoesophageal fistula, previous bariatric surgery, hiatus hernia, large descending

thoracic aortic aneurysm, unilateral vocal cord paralysis, post‑ radiation therapy

Patient refusal to participate in the study

Inability to image the prosthesis satisfactorily to interpret the results

Emergency surgeries.

STUDY PROTOCOL

A total of 40 consecutive patients fulfilling the inclusion criteria were selected as

subjects for the study. Patients were educated about the study in presence of a witness. The

witness was permitted to counter question the patient whether he/she really understood the

proposed study, of which he/she would be a participant. An informed consent form was signed

by patient or relative of the patient as per the Institute protocol.

In the operation room (OR), an adult-size TEE probe was inserted after induction

of general anesthesia and the heart was inspected using an ultrasound system (IE 33, Philips

Ultrasound, Bothell, USA). In the pre-CPB period, hemodynamic parameters and

echocardiographic data were recorded which included peak velocity, peak and mean pressure

gradients, aortic valve area by planimetry and CE, aortic regurgitation severity.

35

Left atrial (LA) anteroposterior diameter was measured in Midesophageal long

axis view (ME LAX) view. LV chamber dimensions were measured in systole and diastole at the

level of insertion of chords onto the mitral valve leaflets, using 2D-TEE in Transgastric 2

Chamber (TG 2C) view. LV wall thickness was measured in systole and diastole using

Transgastric mid-papillary short axis view. LVEF was measured by Simpson’s method using X-

plane view. The aortic valve was examined for the presence of calcification of the leaflets and

annulus. The aortic annulus was measured using Midesophageal aortic valve long axis view (ME

AV LAX). The size of ascending aorta at the level of right pulmonary artery was also measured.

Other valves were examined to rule out any concomitant disease.

CPB was established after adequate heparinisation and aorta was cross-clamped.

Antegrade blood cardioplegia was infused into the aortic root or into the coronary ostia (in the

presence of severe AR) to achieve diastolic arrest of the heart. Diseased aortic valve was excised

and appropriate Chitra heart valve prosthesis (CHVP) was implanted. After implantation of the

CHVP in aortic position, cross clamp was removed and the patients were weaned off from CPB.

Patients were adequately re-warmed and inotropic infusions (as per the Institute protocol) were

commenced before weaning the patient. Heart was examined using TEE before and after the

administration of protamine. Echo data was archived in the hard disc of the echo machine, which

was retrieved later on compact disc. CHVP was re-evaluated using transthoracic

echocardiography 48 hours after the surgery (TTE1) when inotropes were weaned off and stable

hemodynamic condition was achieved. Peak velocity, peak gradient, mean gradient and heart

rate were noted. The patients were kept on follow-up and the above mentioned Doppler

echocardiographic parameters were once again measured by TTE after 3 months (TTE2).

36

EVALUATION OF CHVP AT AORTIC POSITION.

Two dimensional and color Doppler evaluation.

The prosthetic valve was evaluated for valve seating, free leaflet motion, and

angle of opening using intraoperative 2D TEE. The prosthesis was subjected to color Doppler

imaging to detect the presence of any paravalvular leaks and to ascertain the degree of

intravalvular regurgitation before and after the administration of protamine (Figure 3A, 3B& 4).

Spectral Doppler evaluation of aortic valve prosthesis

TEE view in which the Doppler beam could be aligned parallel to the flow of the

prosthetic valve was selected for Doppler evaluation [Transgastric long axis view (TG LAX) and

deep transgastric 5 chamber view (deep TG 5C)]. The following parameters were assessed to

evaluate the prosthetic valve in the aortic position: peak velocity, peak gradient, mean gradient,

AT, AT/ET ratio, contour of the velocity jet, EOA by CE, and DVI.

Major aperture was identified on Color Doppler in TG LAX as well as deep TG

5C views and CWD profile was obtained across the aperture. CWD produced a classical double

envelope VTI pattern across the prosthetic outflow, from which maximal velocity, peak gradient,

mean gradient, acceleration time, ejection time, LVOT VTI, prosthetic valve VTI, were

measured(Figure 5A &5B). EOA of the prosthetic aortic valve was calculated using the CE, as

stroke volume through the LVOT divided by the VTI of the prosthetic aortic valve. Regular R-R

intervals were confirmed whenever EOA or DVI were measured using more than one cardiac

cycle. Peak velocity, peak gradient and mean gradient were obtained in the post-operative period

on TTE in apical 5C view and then these values were compared with the parameters obtained in

37

the intraoperative period. The actual (geometric) orifice area (AOA) published by the

manufacturer was noted.

Projected EOA, projected IOA and required valve size

To avoid PPM, projected EOA was calculated by multiplying BSA of the patient

with 0.85 before surgery. The required size of CHVP to provide the projected EOAwas derived

in the pre-CPB period from the results published by Namboodiri et al14

which were used as

reference values. Projected indexed orifice area (IOA) was calculated from the mean EOA of the

implanted CHVP valves (taken from the published study by Namboodiri et al14

)divided by the

BSA of the patient.

38

STATISTICAL ANALYSIS

All data were entered in Microsoft excel version 2010.The statistical mean and

standard deviation were derived for the continuous variables. The prosthetic valves were divided

into five groups based on their size. Pearson’s correlation coefficient was used for all correlation

evaluations (1. between a Doppler parameter and the size of the CHVP; 2. between

intraoperative TEE and postoperative TTE gradients; 3. between TEE IOA and projected IOA) [r

value: 0 to 0.35 - poor/weak correlation, 0.36 to 0.55 - good correlation and > 0.55 -

significant correlation]. Doppler parameters of post-CPB intraoperative TEE were compared

with TTE parameters obtained 48 hours after surgery and 3 months after surgery, using the

Paired t- test and a p-value < 0.05 was considered significant. Intraoperative TEE CHVP

Doppler parameters were compared with TTE parameters of other mechanical valves from

published data using independent t-test with unequal variances. Fisher’s exact test was used to

compare the non-parametric data for the prediction of PPM by intraoperative TEE.

All statistical analysis were performed using Graphpad Instat software

39

RESULTS AND

OBSERVATIONS

40

RESULTS AND OBSERVATIONS

A total of 40 patients who underwent aorticCHVP replacement without

concomitant repair or replacement of other heart valves were included in the study. They were

divided into 5 groups based on the various sizes of replaced valves. The valve sizes and the

number of patients in each group were 19, 21, 23, 25, 27 mm and 8, 15, 9, 3 and 5 respectively.

The demographic profile and preoperative clinical features of all the patients are portrayed in

Table 5

Table 5: Demographic profile and preoperative clinical features of patients

Abbreviations: BSA:–Body Surface Area; NYHA: - New York Heart Association;

AS: - aortic stenosis; AR: - aortic regurgitation

Total number of patients (n = 40)

Age (years) 42.02 ± 11.85

Sex Male

Female

33 (82.5%)

7 (17.5%)

Height (cm) 163.79 ± 8.93

Weight (kg) 62.50 ± 10.46

BSA (m2) 1.67 ± 0.15

Diagnosis

Degenerative

Rheumatic

Bicuspid

21 (52.5%)

10 (25%)

9 (22.5%)

Predominant AS

Predominant AR

21 (52.5%)

19 (47.5%)

NYHA Class

Class II

Class III

23 (57.5%)

17 (42.5%)

Rhythm Sinus 40

41

Table 5 shows that the average age of the study subjects involved in the study was 42.02 ± 11.85

years. Males were in a larger proportion (82.5%) compared to the females (17.5%). The most

common pathology was degenerative disease (52.5%), followed by rheumatic and bicuspid aortic

valve. Both stenosis and regurgitation lesions were prevalent among the patients. Majority of the

patients presented with NYHA class II symptoms (57.5%), whereas 42.5% patients presented

with NYHA class III symptoms. All the 40 study subjects were in normal sinus rhythm.

Table 6:- Distribution of valve sizes and the number of patients in each group.

Table 6 shows distribution of five different sizes of CHVP implanted at aortic position. Majority

of the patients were implanted with 21 mm valve (37.5%). The 19 mm and 23mm valves

wereimplanted in 20% and 22.5% of patients respectively. This was followed by 27 mm valve

(12.5%). A small proportion of patients (7.5%) received 25 mm valve.

Valve Size

Number of patients

Percentage

19 mm 8 20 %

21 mm 15 37.5 %

23 mm 9 22.5 %

25 mm 3 7.5 %

27 mm 5 12.5 %

Total 40

42

Table 7:Pre-CPB TEE observations

Echocardiographic parameters (intraoperative pre-CPB TEE)

LVID (mm)

Diastole

50.96 ± 10.63

LVID (mm)

Systole

35.73 ± 9.00

Ejection fraction (%)

58.47 ± 7.73

LA size (mm)

40.61 ± 8.22

Aorta size (mm)

28.83 ± 3.58

Septal wall

(mm)

Systole

18.69 ± 3.63

Diastole

15.97 ± 3.44

Inferior wall

(mm)

Systole

17.24 ± 2.99

Diastole

14.62 ± 2.93

Abbreviations: TEE: – Transesophageal echocardiography; CPB: – Cardiopulmonary bypass;

LVID: – Left ventricular internal diameter; LA: – left atrium; LV: – Left ventricle

Table 7 shows the intraoperative TEE observations during the pre-CPB period. LV function was

found to be good in the study subjects with an average ejection fraction of 58.47 ± 7.73 %.

Average LV dimensions were suggestive of mild LV dilatation. None of the patients had dilated

ascending aorta. Septal wall thickness > 20 mm was found in 14 patients; however, none had any

Systolic anterior motion (SAM) potential and hence septal resection was not needed.

43

All prosthetic valves were evaluated by TEE in the post-CPB period after the

administration of protamine. 2D TEE for degree of leaflet mobility, angle of leaflet opening, and

stability of valve seating; color Doppler examination for any paravalvular or intravalvular leaks;

and spectral Doppler assessment for peak velocity, peak and mean gradients, AT, AT/ET, DVI

and EOA by continuity equation were performed (Figure 3A, 3B,4,5A and 5B).

None of the patients had restriction of leaflet mobility or abnormal seating of the

valve. Angle of leaflet opening was 60 to 70 degrees in all patients. A trivial paravalvular leak

was noticed in two patients which disappeared after the administration of protamine.

Figure 3:(A) ME AV short axis view showing normal seating of CHVP, (B) Color Doppler in

ME AV long axis view showing free flow across the CHVP in open position (yellow arrow)

44

Figure 4: Color Doppler across the CHVP in deep TG 5C view showing washing jets at hinge

points (white arrow)

Figure 5: (A) The CHVP evaluated in TG 5-Ch view using CWD depicts double envelope

pattern of VTI; the inner dense and outer semi-dense envelope representing the LVOT and

prosthetic valve VTI respectively. Measured parameters including peak velocity, peak and mean

pressure gradients, DVI and effective orifice area are shown in the figure (B) measurement of

acceleration time (AT) which is the time required for the flow to reach the peak velocity from

baseline

45

Doppler parameters evaluated from intraoperative TEE showed that the flow

dependent parameters such as peak velocity, peak and mean gradient decreased with increase in

the valve size while the flow independent parameters such as AT, DVI, AT/ET remained

constant and within the normal range. EOA which is a flow independent parameter increased

with increase in valve size. (Table 8 and Figure 6)

Figure 6:-Spectral Doppler parameters of various sizes of CHVP studied

Figure 6:depicts Doppler parameter values (Y-axis) obtained for varioussizes of CHVP (X-axis).

Peak velocity, peak gradient and mean gradient decreased significantly with increase in the valve

size, whereas the flow independent parameters such as DVI, AT and AT/ET ratio showed no

significant change with increase in the valve size. EOA by CE increased with increase in valve

size. The peak velocity and the pressure gradients were in higher normal range for small-sized

valves(19 and 21 mm).

46

Table 8:-Intraoperative post-CPB Doppler parameters of various sizes of aortic CHVP and their

correlation with the valve size

Table 8: peak velocity, peak and mean gradients showed significant negative correlation with

increase in the size of CHVP; EOA and IOA had significant positive correlation with the size of

the prosthesis; DVI, AT and AT/ET had a weak correlation with the size of the prosthesis; Heart

rate among the groups did not vary significantly. [Abbreviations: - DVI: - Doppler velocity

index; AT: – Acceleration time; AT/ET: -Acceleration time/ Ejection time ratio; EOA: -

effective valve area; IOA: - Indexed orifice area; CE: - continuity equation]

Pearson correlation co-efficient [r]:- positive value denotes direct correlation whereas negative

value signifies inverse correlation. (0 to 0.35-poor/weak correlation, 0.36 to 0.55- good

correlation, > 0.55 significant correlation).

19 mm

21mm

23 mm

25 mm

27 mm

#CORRELATION

Peak velocity

(m/sec)

2.91±0.13

(2.78 – 3.2)

2.56±0.32

(1.58 – 2.9)

2.47±0.30

(1.87 – 2.78)

2.19±0.28

(1.87 – 2.4)

1.86±0.24

(1.6 – 2.03)

r = - 0.7610

p <0.0001

Peak Gradient

(mm Hg)

34.10±3.08

(31 – 41)

26.92±5.93

(10.1 –35.2)

24.93±5.61

(14 – 30.92)

19.33±4.72

(14 – 23.1)

13.3±3.69

(10.2 –17.6)

r = - 0.7714

p <0.0001

Mean Gradient

(mm Hg)

19.97±1.53

(18.1 – 23)

15.43±3.86

(5 – 20.2)

13.85±3.18

(8.1 – 18.6)

9.66±1.52

(8 – 11)

7.3±1.86

(5.1 – 9.6)

r = - 0.7888

p < 0.0001

Heart rate 85.12±10.97

(64 – 103)

84.8±8.58

(69 – 90)

87.77±9.85

(74 – 100)

87.33±8.08

(80 – 96)

87.8±4.14

(84 – 94)

r = 0.1310

p = 0.4203

AT

(msec)

69.87±12.28

(52 – 95)

66.4±9.14

(40 – 77)

63.44±15.03

(41 – 78)

63.33±4.72

(58 – 67)

62.6±6.98

(52 – 70)

r = - 0.2170

p = 0.1787

AT/ET

0.28±0.04

(0.21 – 0.34)

0.26±0.04

(0.17 –0.38)

0.26±0.02

(0.2 – 0.31)

0.25±0.04

(0.21 -0.28)

0.25±0.03

(0.21 – 0.3)

r = - 0.2084

p = 0.1968

DVI

0.38±0.08

(0.3 -0.5)

0.42±0.06

(0.34 -0.5)

0.40±0.08

(0.3 -0.5)

0.46±0.05

(0.4 -0.5)

0.46±0.14

(0.4 -0.5)

r = 0.3493

p = 0.0271

EOA by CE

(cm2)

1.35±0.21

(0.96 – 1.61)

1.61±0.19

(1.22 –1.98)

2.04±0.14

(1.75 – 2.24)

2.19±0.13

(2.12 –2.35)

2.44±0.04

(2.4 -2.51)

r = 0.9010

p = <0.0001

IOA (cm2)

0.87±0.08

(0.78 – 0.95)

0.94±01

(0.73 – 1.1)

1.16±0.08

(1.08 – 1.3)

1.19±0.11

(1.1 – 1.3)

1.38±0.12

(1.2 – 1.5)

r = 0.8381

p = <0.0001

47

Figure 7: Correlation between peak velocity, peak gradient and mean gradient with the different

sizes of aortic CHVP

The flow dependent parameters such as peak velocity (r = -0.7610), peak gradient

(r = -0.7714) and mean gradient (r = -0.7888) showed significant inverse relation with the

increase in the size of the prosthesis. Smaller sized valves (19 and 21 mm) in some patients

displayed higher mean gradients (> 20 mm Hg) without affecting hemodynamic condition.

-10

0

10

20

30

40

1

1.5

2

2.5

3

3.5

4

4.5

5

5.5

6

17 19 21 23 25 27 29

Pea

k a

nd

Mea

n G

rad

ien

t (m

m H

g)

Pea

k V

eloci

ty (

m/s

ec)

Size of Chitra Heart Valve Prosthesis

Peak Velocity (m/sec) Peak Gradient (mm Hg) Mean Gradient (mm Hg)

Linear (Peak Velocity (m/sec)) Linear (Peak Gradient (mm Hg)) Linear (Mean Gradient (mm Hg))

r = - 0.7610

p < 0.0001

r = -0.7714

p < 0.0001

r = - 0.7888

p < 0.0001

48

Figure 8: Correlation between Doppler velocity index, AT/ET, Acceleration time and heart

rate with the different sizes of aortic CHVP

DVI (r = 0.3493), AT/ET ratio (r = -0.2084), acceleration time (r = - 0.2170) and

heart rate (r = 0.1310) displayed poor correlation with the increase in valve size. Heart rate was

maintained within the average range of 70 to 85 per minute during the measurement of Doppler

parameters.

0

20

40

60

80

100

120

0.1

0.3

0.5

0.7

0.9

1.1

1.3

1.5

17 19 21 23 25 27 29

Acc

eler

ati

on

Tim

e (m

s) &

Hea

rt R

ate

per

min

Dop

ple

r V

eloci

ty I

nd

ex &

AT

/ET

Size of Chitra Heart Valve Prosthesis

Doppler velocity index AT/ET Acceleration Time (ms)

Heart Rate Linear (Doppler velocity index) Linear (AT/ET)

Linear (Acceleration Time (ms)) Linear (Heart Rate)

r = 0.1310

p = 0.4203

r = - 0.2170

p = 0.1787

r = 0.3493

p = 0.0271

r = -0.2084

p = 0.1968

49

Figure 9: Correlation between the effective orifice area and indexed orifice area with the

different sizes of aortic CHVP

The effective orifice area and the indexed orifice area calculated by continuity equation

increased significantly with increase in the size of the CHVP depicting a significant positive

correlation (r = 0.9010 and r = 0.8381 respectively).

[r – Pearson correlation co-efficient: positive value signifies direct correlation and values close

to 1 indicates significant correlation.]

0

0.5

1

1.5

2

2.5

3

3.5

4

0

0.5

1

1.5

2

2.5

3

17 19 21 23 25 27 29

Ind

exe

d O

rifi

ce A

rea

(cm

2/m

2 )

Effe

ctiv

e O

rifi

ce A

rea

(cm

2)

Size of Chitra Heart Valve ProsthesisEffective Orifice Area (cm2) Indexed Orifice Area (cm2/m2)

Linear (Effective Orifice Area (cm2)) Linear (Indexed Orifice Area (cm2/m2))

r = 0.9010

p < 0.0001

r = 0.8381

p < 0.0001

50

Table 9:- Comparison of Doppler parameters between intraoperative TEE and postoperativeTTE

on 3rd

post-operative day (TTE1).

Table 9: The intraoperative TEE Doppler parameters and heart rate were compared with the TTE

data (TTE1) on 3rd

postoperative day. The intraoperative peak velocity and pressure gradients

were slightly higher with all valve sizes except for 27 mm valve where the postoperative

gradients were higher, although there was no statistical difference among the parameters. Heart

rate obtained at different time periods had no statistically significant difference.

CHVP

Peak velocity

(m/sec)

Peak gradient

(mm Hg)

Mean gradient

(mm Hg)

Heart rate

per min

19 mm

TEE 2.91±0.13 34.10±3.08 19.97±1.53 85.12±10.97

TTE1 2.81±0.21 30.25±6.29 18.12±4.15 84.12±10.17

p value 0.2567 0.1298 0.2498 0.8328

21mm

TEE 2.56±0.32 26.92±5.93 15.43±3.86 84.8±8.58

TTE1 2.46±0.27 25.2±5.21 14.8±3.18 84.13±8.15

p value 0.1821 0.2083 0.5198 0.8309

23 mm

TEE 2.47±0.30 24.93±5.61 13.85±3.18 87.77±9.85

TTE1 2.23±0.35 20.88±6.64 12.17±4.26 84.33±9.05

p value 0.0680 0.0949 0.2775 0.2950

25 mm

TEE 2.19±0.28 19.33±4.72 9.66±1.52 87.33±8.08

TTE1 2.06±0.15 18.0±2.64 10±1.73 87±3.00

p value 0.2490 0.3828 0.4226 0.9388

27 mm

TEE 1.80±0.24 13.3±3.69 7.3±1.86 87.8±4.14

TTE1 2.02±0.13 16.8±2.58 10.12±1.33 79.4±9.58

p value 0.2582 0.2696 0.1087 0.2190

51

Figure 10:Correlation between the intraoperative TEE and 3rd

postoperative day TTE1

Doppler parameters of CHVP

Peak velocity (r = 0.7154), peak gradient (r = 0.6883) and mean gradient (0.6436) assessed by

transthoracic echocardiography on 3rd

postoperative day (TTE 1) showed a significant direct

correlation with the intraoperative Doppler parameters measured by transesophageal

echocardiography, suggesting that the values of Doppler parameters obtained on intraoperative

TEE strongly predict the postoperative values of Doppler parameters on TTE examination.

[r – Pearson correlation co-efficient: positive value signifies direct correlation and values close

to 1 indicates significant correlation.]

5

10

15

20

25

30

35

40

1.5

3

1 2 4 8 16 32 64

3rd

Po

sto

pe

rati

ve d

ay (

TTE1

) -

Pe

ak a

nd

me

an g

rad

ien

t

3rd

Po

sto

pe

rati

ve d

ay (

TTE1

) -

Pe

ak v

elo

city

Intraoperative TEE

Peak Velocity (m/sec) Peak gradient (mm Hg)

Mean Gradient (mm Hg) Linear (Peak Velocity (m/sec))

Linear (Peak gradient (mm Hg)) Linear (Mean Gradient (mm Hg))

r = 0.7154

p < 0.0001

r = 0.6883

p < 0.0001

r = 0.6436

p < 0.0001

52

Table 10:- Comparison of Doppler parameters between intraoperative TEE and postoperative

TTE after 3 months of surgery (TTE2)

Table 10 reveals that the values for peak velocity, peak gradient and mean gradient reduced as

the size of CHVP increased from 19 mm to 27 mm. Doppler parameters were not statistically

different for the same size valves when measured in the intraoperative period and 3 months after

the surgery. Heart rate remained in the same range among these patients in the post-CPB period

and 3 months after surgery.

CHVP

Peak velocity

(m/sec)

Peak gradient

(mm Hg)

Mean gradient

(mm Hg)

Heart rate

per min

19 mm

TEE 2.91±0.13 34.10±3.08 19.97±1.53 85.12±10.97

TTE2 2.9±0.41 34.62±9.29 20.12±5.69 87.87±13.94

p value 0.9871 0.8829 0.9448 0.5816

21mm

TEE 2.56±0.32 26.92±5.93 15.43±3.86 84.8±8.58

TTE2 2.64±0.39 28.33±8.25 16±5.02 83.20±12.37

p value 0.4577 0.5340 0.7063 0.5732

23 mm

TEE 2.47±0.30 24.93±5.61 13.85±3.18 87.77±9.85

TTE2 2.35±0.25 22.22±4.58 12.67±2.40 82.33±18.11

p value 0.3680 0.2918 0.4504 0.3660

25 mm

TEE 2.19±0.28 19.33±4.72 9.66±1.52 87.33±8.08

TTE2 2.19±0.17 19.33±2.89 10.00±0.87 79±4.58

p value 0.9900 0.9999 0.8218 0.2863

27 mm

TEE 1.80±0.24 13.3±3.69 7.3±1.86 87.8±4.14

TTE2 2.02±0.29 16.8±4.55 9.4±3.21 79.40±8.20

p value 0.3864 0.3711 0.3777 0.0839

53

Figure 11:Correlation between the intraoperative TEE and postoperative TTE (TTE2)

Doppler parameters of CHVP

Peak velocity (r = 0.5426), peak gradient (r = 0.5393) and mean gradient (0.5286) assessed by

TTE after 3 months of surgery (TTE2) showed a good and statistically significant direct

correlation with the intraoperative Doppler parameters measured by TEE.

[r – Pearson correlation co-efficient:positive value signifies direct correlation and values close to

1 indicates significant correlation.]

0

5

10

15

20

25

30

35

40

45

50

1

2

4

1 2 4 8 16 32 64

Foll

ow

up

aft

er 3

mon

ths

(TT

E2

) -

Pea

k a

nd

mea

n g

rad

ien

t

Foll

ow

up

aft

er 3

mon

ths

(TT

E2

) -

Pea

k v

eloci

ty

Intraoperative TEE

Peak Velocity (m/sec) Peak Gradient (mm Hg)

Mean gradient (mm Hg) Linear (Peak Velocity (m/sec))

Linear (Peak Gradient (mm Hg)) Linear (Mean gradient (mm Hg))

r = 0.5426

p = 0.0003

r = 0.5393

p = 0.0003

r = 0.5286

p = 0.0005

54

Table 11: Patient-prosthesis mismatch detection by intraoperative TEE

The IOA > 0.85 cm2/m

2 was regarded as absence of PPM and IOA < 0.85 cm

2/m

2 was regarded

as presence of PPM as per ASE guidelines. The required size of CHVP to provide IOA of > 0.85

cm2/m

2 was derived in the pre-CPB period from the results published by Namboodiri et

al14

which were used as reference values. We predicted that if the derived size of CHVP would be

implanted in aortic position, there would not be any PPM in the post-CPB period. TEE

examination was performed in the post-CPB period and IOA of the implanted CHVP was

measured. Also, the size of CHVP implanted was noted. We tested the sensitivity, specificity,

positive predictive value and negative predictive value of intraoperative TEE towards detecting

the presence of PPM (when the predicted size of CHVP was implanted, as well as when the

predicted size was not implanted). The results are mentioned in the Table 11.All the results were

statistically significant (P value < 0.0001).

Predicted-required

CHVP as per size & IOA

(n = 40)

Predicted CHVP

size not implanted

(n = 16)

[PPM present]

Predicted CHVP

size implanted

(n = 24)

[PPM absent]

Value (confidence interval)

IOA by TEE

< 0.85 cm2/m2

(n = 9)

9 (23%)

0

Sensitivity: 56.25 %

(29.88% to 80.25%)

Specificity: 100 % (85.75 %

to 100%)

Positive predictive value:

100% (66.37% to 100%)

Negative predictive value:

77.42% (58.90% to 90.41%)

IOA by TEE

≥ 0.85 cm2/m

2

(n = 31)

7 (17%)

24 (60%)

55

None of the patients in whom the predicted size of CHVP was implanted, developed PPM. All

the patients who developed PPM were those in whom the predicted CHVP size was not

implanted. Seven patients in whom the predicted size of CHVP was not implanted, had no PPM.

Figure 12:Correlation between the projected (IOA) and intraoperative TEE derived IOA

The projected indexed orifice area showed a good and statistically significant direct correlation

with the intraoperative IOA measured by transesophageal echocardiography (r = 0.4886).

(r – Pearson correlation co-efficient, positive value close to 1 indicatessignificant correlation,

whereas positive value signifies direct correlation.)(Abbreviations: - IOA – indexed orifice area,

TEE – transesophageal echocardiography)

0.5

0.7

0.9

1.1

1.3

1.5

1.7

0.5 0.7 0.9 1.1 1.3 1.5 1.7

Intr

ao

per

ati

ve

TE

E I

OA

(cm

2/m

2)

Projected IOA (cm2/m2)

r = 0.4886

p = 0.0014

56

Table 12:- Comparison of intraoperative TEE Doppler parameters of CHVP with the published

TTE data of St. Jude Medical Bileaflet mechanical valve prosthesis 18

[Abbreviations: - DVI- Doppler velocity index, SJM (BL) – St. Jude Medical Bileaflet, CHVP

– Chitra Heart Valve Prosthesis]

Valve

Size

Peak

velocity

(m/sec)

Peak

gradient

(mm Hg)

Mean

gradient

(mm Hg)

DVI

Effective

orifice

area

(cm2)

LVOT

Diameter

(cm)

19 mm

CHVP 2.91±0.13 34.10±3.08 19.97±1.53 0.38±0.08 1.35±0.21 1.97±0.10

SJM (BL) 3.0±0.6 37.10±16.06 17±7 0.37±0.07 0.99±0.20 1.85+0.07

p value 0.6726 0.2178 0.2501 0.7890 0.0029 0.0151

21mm

CHVP 2.56±0.32 26.92±5.93 15.43±3.86 0.42±0.06 1.61±0.19 2.22±0.22

SJM (BL) 2.7±0.3 30.07±6.35 14±5 0.40±0.06 1.25±0.21 2.00+0.04

p value 0.2349 0.1799 0.3995 0.3780 <0.0001 0.0019

23 mm

CHVP 2.47±0.30 24.93±5.61 13.85±3.18 0.40±0.08 2.04±0.14 2.41±0.22

SJM (BL) 2.8±0.5 31.88±11.86 16±6 0.37±0.06 1.28±0.31 2.10+0.12

p value 0.0513 0.0600 0.2543 0.3447 < 0.0001 0.0029

25 mm

CHVP 2.19±0.28 19.33±4.72 9.66±1.52 0.46±0.05 2.19±0.13 2.73±0.16

SJM (BL) 2.6±0.5 27.37±9.93 13±6 0.42±0.08 1.8±0.41 2.32+0.15

p value 0.1080 0.0790 0.0907 0.3279 0.1318 0.0608

27 mm

CHVP 1.80±0.24 13.3±3.69 7.3±1.86 0.46±0.14 2.44±0.04 2.88±0.25

SJM (BL) 2.2±0.5 21.73±9.13 11±5 0.46±0.10 2.43±0.63 2.58±0.20

p value 0.1264 0.0850 0.1442 0.9999 0.9706 0.0669

57

We observed no difference with respect to peak velocity, peak gradient, mean gradient and DVI

among CHVP and the St. Jude valve of same sizes. The LVOT diameter and EOA of CHVP

were significantly higher for 19, 21 and 23mm valves when compared to St. Jude valves of same

sizes. There was no difference with respect to LVOT diameter and EOA among CHVP and the

St. Jude valve of sizes 25 and 27 mm. The EOA measurement is significantly affected by the

LVOT diameter because any variations in the measurement are squared during calculation of

cross sectional area.

58

DISCUSSION

59

DISCUSSION

Chitra heart valve prosthesis (CHVP) is an indigenous, tilting-disc heart valve

developed by the Sree Chitra Tirunal Institute for Medical Sciences and Technology

(SCTIMST), India40

. It has gained a huge acceptance all over the nation because of its low cost,

high excellence and durability. After its first implantation in December 1990, a potential market

was established for the valve in India, neighboring countries, as well as South Africa. Till now,

CHVP has nearly 100,000 implantations to date. The clinical efficacy and the normal

postoperative transthoracic echocardiographic parameters of CHVP have been well studied and

reported in literature13, 41

. The postoperative CHVP Doppler parameters implanted at mitral and

aortic positions were comparable with those obtained with the different mechanical valves in

common practice14, 15

.

Intraoperative TEE has become an essential imaging modality during heart valve

surgeries42

. Studies have shown that post-CPB TEE has a major impact on the outcome of valve

replacement surgeries43, 44

. Current ASE/SCA guidelines have strongly endorsed the use of TEE

for the assessment of prosthetic heart valves to establish baseline reference values immediately

after valve replacement2. Therefore, it is necessary to define the intraoperative echocardiographic

characteristics and flow profile of different sizes of CHVP using 2D, color flow Doppler and

spectral Doppler examination.Although CHVP has been in use for more than 25 years and

postoperative follow up studies have reported excellent long term clinical outcomes, no reports

are available in the literature which describe the intraoperative TEE Doppler parameters of

CHVP at the aortic position.

60

Hence, we planned this study to establish a reference for the normal intraoperative

echocardiographic parameters of CHVP at aortic position using TEE in the post-CPB period. We

compared this data with the postoperative TTE Doppler parameters obtained 48 hours after

surgery when the inotropes were weaned off and later 3 months following the surgery. The

correlation of echocardiographic data between the intraoperative and postoperative follow-up

period was derived. The normal Doppler echocardiographic data of CHVP obtained in this study

was also compared with the published Doppler parameters of other prosthetic valves in common

practice. The sensitivity and specificity of intraoperative TEE to predict PPM was also evaluated.

We have obtained intraoperative TEE data in 40 patients implanted with five different sizes of

CHVP (19, 21, 23 25 and 27mm) at aortic position. Even though 17 and 29 mm size valves are

also available, they are uncommonly implanted and hence not included in our study.

Hemodynamic state during intraoperative and postoperative period

Measurement of Doppler velocities and gradients across the prosthetic valve in

the immediate post-CPB period are influenced by various confounding factors45

. During this

period, the loading conditions of the heart are altered by surgical site bleeding, infusion of intra-

venous fluids, return infusion of CPB reservoir blood,and transfusion of blood. Frequent changes

in the preloading conditions resulting from an inconsistent intravascular volume status may vary

the flow across the prosthetic valve and the measurement of flow dependent Doppler parameters.

Therefore, in order to perform an accurate Doppler evaluation of prosthetic valves, it is essential

to maintain a constant loading condition prior to Doppler examination. Increased contractility

induced by the inotropic supports in the immediate post-CPB period may increase the cardiac

output producing false high gradients across the prosthetic valves. Absence of atrial phase of LV

diastolic filling during ventricular pacing reduces the preload and stroke volume in the post-CPB

61

period. High cardiac output state may be produced by inotrope-induced tachycardia and

hemodilution from CPB prime, which elevates the peak velocity and pressure gradients.

In our study, we maintained constancy of preloading conditions by keeping the

central venous pressure (CVP) between 10 to 12 mm Hg before measuring the Doppler

parameters. Maintaining the hematocrit at around 30 % in all the patients during TEE

examination minimized the consequences of hemodilution on Doppler measurements. Since the

patients included in our study had good LV systolic function (LVEF = 58.47 ± 7.73 %),

inotropes were rarely needed in the post-CPB period.

Post-operative TTE evaluation was done twice; first on the 3rd

post-operative day

and the second after 3 months. By day 3, the inotropic support was weaned off and the patients

were hemodynamically stable. The prosthesis was also evaluated 3 months after the surgery

expecting maximum regression of the LV hypertrophy, improvement in the LV systolic function

and functional class, and resorption of paravalvular edema. The hemodynamic condition of all

the patients was stable during the postoperative follow up period.

The Doppler profiles archived during intraoperative period, 3rd

post-operative day

and 3 months after surgery were not significantly different despite the presence of high cardiac

output state and proactive hemodynamic factors such as inotropes, hemodilution, tachycardia and

cardiac pacing in the intraoperative period. It suggests that these factors have an insignificant

effect on the intraoperative Doppler characteristics, which may be treated as the reference values

for future Doppler studies conducted during the follow-up period.

62

2D and color Doppler evaluation of aortic CHVP

The two dimensional and color Doppler TEE features of CHVP were compliant

with the recommendations by ASE for prosthetic valve evaluation5. On 2D echo examination,

the sewing ring was found to be stable in all patients without any dehiscence or rocking motion.

The movement of the occluder disc was free making an angle of opening between 60 and 70

degrees. Color Doppler interrogation across the prosthetic valve revealed the major and minor

orifices occupying 70 % and 30 % of the internal geometric area respectively. Distinctive one to

two washing jets were observed in all the patients. No significant pathological transvalvular

regurgitation was noted in any of the patients. Trivial paravalvular leak at the suture sites noticed

in two patients immediately after CPB was weaned off, disappeared after administration of

protamine.

Spectral Doppler assessment of CHVP

The systematic assessment of prosthetic aortic valve has been described in the

ASE guidelines5. The Doppler parameters to be evaluated were contour of the velocity jet, peak

velocity, mean and peak gradient, DVI, AT, AT/ET ratio, EOA, IOA. When the peak velocity

exceeds 3 m/sec and the DVI remains below 0.3, then the prosthetic valve needs further

evaluation (Figure 2). The likely causes may be prosthetic valve stenosis or dysfunction, high

flow across the valve, patient prosthetic mismatch (PPM), improper Doppler insinuation of

LVOT, and sub-valvular narrowing. Tachycardia (heart rate >100/min) may also falsely raise the

pressure gradients. In our study only one patient with 19 mm valve had a peak velocity of more

than 3 m/sec (3.2m/sec).Further analysis of this patient, revealed DVI of 0.31, triangular early

peaking velocity jet, acceleration time of 76 msec and an indexed orifice area of 0.78 cm2/m

2. In

this patient, we diagnosed moderate PPM in a normally functioning prosthetic valve.

63

Doppler-derived velocity and gradients

Application of modified Bernoulli equation provides precise estimation of

pressure gradients across the normal prosthetic valves and at various degrees of valve stenosis in

the absence of sub-valvular obstruction46, 47

. Studies have demonstrated a very good correlation

between the Doppler gradients derived by Bernoulli equation and those measured by catheter

study in a recipient of a prosthetic valve. This correlation was demonstrated in the recipients of

various types of prosthetic heart valves48, 49

. However, the flow velocity and the pressure

gradients across the valve may differ among valves of different designs, sizes and at variable

flow conditions 50- 52

. In our study, we observed a significant inverse correlation of peak velocity

and pressure gradients with the increase in the valve size. There is evidence from numerous

studies that even though an inverse relation occurs between the valve size and pressure gradients,

the pressure gradients may display overlap among same sizes of different prosthetic valve

designs and also among the different sizes of the same prosthetic valve design53-55

. The high flow

conditions generate a major impact on pressure gradients produced across the valve. We also

found a significant overlap of the range of pressure gradients among different CHVP sizes which

we attribute to the high flow conditions rather than size of the valves. The Doppler gradient

observations of our study are consistent with the previous studies on aortic CHVP where the

gradients were measured after 3 months of surgery14

.

Contour of the velocity jet, acceleration time and AT/ET ratio

The contour of the velocity jet is a qualitative parameter that is used in

combination with quantitative indices like acceleration time and ratio of acceleration time to

ejection time (AT/ET ratio) to provide a valuable guide on prosthetic valve function. In a normal

functioning prosthetic valve, even during high flow rate, the shape of the jet is triangular with

64

early peaking and the AT is less than 100 ms. In the presence of any intrinsic valve stenosis or

obstruction, the contour becomes rounded, peaking during mid-ejection accompanied with

prolongation of AT and AT/ET ratio (AT > 100 ms and AT/ET > 0.4)56-58

. These parameters are

independent of flow and Doppler angulation. In our study the contour of the velocity jet was

triangular and early peaking in all the patients. The mean AT and AT/ET ratio were < 100 ms

and < 0.4 respectively and showed a poor correlation with the increase in the valve size. These

findings are acquiescent with ASE guidelines in differentiating a normal aortic prosthetic valve

from a stenotic one5.

Doppler velocity index

Another flow independent parameter recommended by the ASE to assess the

aortic prosthetic valve function is Doppler velocity index (DVI). It is a dimensionless index

calculated from the ratio of LVOT VTI to prosthetic valve VTI. DVI reflects the effect of flow

through the prosthetic valve on Doppler velocity18

. Therefore it may provide a guide to screen

valve dysfunction when the valve size or LVOT area is not known. In our study, DVI showed a

weak correlation with the valve sizes and the least value was 0.29 seen in two patients of 19 mm

size valve. A DVI < 0.25 suggests significant valve obstruction.DVI of a valve should be

referencedto normal values of a particular valve size59

. The DVI values of our study showed no

significant difference on comparison with the DVI of previous published studies on aortic

CHVP14

.

Effective orifice area by continuity equation

Effective orifice area (EOA), another flow independent parameter is derived from

the LVOT stroke volume using the continuity equation:

65

EOA = (LVOT area x LVOT VTI) / ProstheticAortic Valve VTI

Derived value of EOA depends on the size of the implanted valve. The EOA of a

valve should be referencedto normal values of a particular valve size. The EOA of CHVPs in our

study showed a significant direct correlation with the valve sizes. The average value for the 19

mm size valve was 1.35 cm2 and the lowest measured value was 0.96 cm

2. On comparison with

EOA values of published studyusing TTE14

, our EOA values were found to be significantly

higher. However, in our study, values of DVI were comparable with the values of DVI obtained

in the previous published TTE study14

.Studies have demonstrated that the major source of

variability in the calculation of EOA is the inconsistency in the measurement of LVOT

diameter60

. This inconsistency may be due to interference of prosthesis shadows, foreshortening

of LVOT, reverberation artifacts and the grade of septal hypertrophy below the annulus18

. The

subset of patients were different between our study and the previous published TTE study of

aortic CHVP14

, where the LVOT diameter could have differed between the two subset of

patients. This may be the reason for significant difference in EOA. In addition, the advances in

technology (X matrix vs conventional 2D phased array probes) and interrogation window (TTE

vs TEE) may also influence the LVOT measurements. It has been reported that TEE offers more

accuracy and reproducibility in the measurement of LVOT diameter than TTE, with which the

values may be underestimated61, 62

. Since there are no reported TEE studies on CHVP, we

compared our EOA values with those of previous TTE studies.

Indexed orifice area and patient prosthesis mismatch (PPM)

Patient-prosthesis mismatch is a common clinical problem in patients of aortic valve replacement

resulting in high transprosthetic gradient across a normally functioning valve63

. It is a long-term

problem having significant impact on improvement in functional capacity, hemodynamic status,

66

morbidity and mortality. According to literature, the best parameter used to describe PPM is

indexed orifice area (effective orifice area of the prosthetic valve / BSA of the patient) 20, 64

. The

severity of PPM is classified based on the IOA as65, 66

:no PPM – IOA ≥ 0.85 cm2/m

2, moderate

PPM – IOA 0.65-0.85 cm2/m

2 and severe PPM – IOA < 0.65 cm

2/m

2. Although, in our study the

mean IOA values of 19 mm and 21 mm CHVP are 0.87 cm2/m

2 and 0.94 cm

2/m

2 respectively, 4

patients in 19 mm and 5 patients in 21 mm valve group had moderate PPM according to the

above mentioned classification. However, among the 9 patients, only one patient in 19mm valve

group had peak velocity of > 3 m/sec while the others had values in higher normal range (Peak

velocities 2.8 - 3 m/sec). In our patients, moderate PPM (as assessed using IOA) detected by

intraoperative TEE was 23% which coincides well with the reported prevalence rate of previous

studies67, 68

.

Comparison of intraoperative TEE gradients with postoperative TTE gradients

Measurement of intraoperative TEE gradients is influenced by various

perioperative factors45

. We compared and correlated the TEE parameters with those of

postoperative TTE done after 48 hours (TTE1) and after 3 months of surgery (TTE2) in our

patients. The early postoperative (TTE1)gradients obtained after weaning offthe inotropes and

stabilization of hemodynamic state showed relatively lesser gradients (than TEE) except for 27

mm valves, although the differences were statistically insignificant. The late postoperative

(TTE2)gradients were found to be comparable with TEE gradients. We found a statistically

significant good positive correlation of peak velocity, peak gradient and mean gradient between

the intraoperative TEE and postoperative TTE values (TTE1 and TTE2). These findings did not

agree with those by Levy et al 26

where they assessed the TEE Doppler gradients immediately

after weaning the patient from CPB before protamine administration and compared them with

67

TTE values obtained at 2-4 months after surgery. In our study, we assessed both flow-dependent

and flow-independent parameters after the administration of protamine and optimization of

loading conditions and hematocrit. The fact that our assessment was done after protamine

administration and achieving hemodynamic stability, might have given a better correlation

between the intraoperative TEE values and postoperative TTE values in our study. Neither

assessment of flow-independent parameters in the intraoperative period, nor the re-evaluation of

Doppler parameters 48 hours after the surgery were the objectives of the study by Levy et al. In

our study, we measured flow-independent parameters AT, AT/ET, DVI and EOA which were

comparable with the published TTE studies of aortic CHVP. Flow-independent parameters

depict valve function better than the flow-dependent parameters like peak velocity and mean

gradient which may be influenced by the use of inotropes, tachycardia and high output states in

the post-operative period.

Comparison between CHVP and St. Jude Medical prosthesis

In the late 1970s, St. Jude medical prosthesis (SJM) was introduced into the

clinical practice. It is a bileaflet valve and its structure consists of a distinct hinge mechanism

where two crescent leaflets function in synchrony inside the annulus of the valve. It has an

excellent hemodynamic profile and its efficacy in aortic position has been demonstrated by

numerous clinical studies69, 70

. Since SJM implantation is most common in clinical practice, we

compared our intraoperative TEE Doppler parameters of aortic CHVP with the established

reference values of St. Jude medical (SJM) aortic prosthesis18

. The peak velocity, peak gradient,

mean gradient and DVI showed no significant difference between CHVP and SJM of same valve

sizes. On comparison between, CHVP and SJM of same valve sizes, the EOA showed a

significant difference for 19, 21 and 23 mm valve groups whereas it was comparable for 25 and

68

27 mm valves. The EOA measurement varies with the LVOT cross sectional area (CSA). Since

the calculation of DVI was independent of LVOT CSA, the DVI values among the CHVP and

St. Jude valves were not statistically different. Also, the subset of patients were different between

the two studies. Probably that could explain the observed difference in the EOA between CHVP

and SJM of same valve sizes.

Prediction of PPM by intraoperative TEE

Studies have shown that PPM can be avoided by implanting a valve that will

provide an adequate indexed EOA. The desired size and make of the prosthesis can be predicted

using the normal reference values from the published data65

. However, sometimes, the surgeon

may not be able to place the required valve due to anatomical constraints71, 72

. The prediction of

PPM by intraoperative TEE has not been studied previously. Projected indexed orifice area

calculated from the EOA of the valve to be implanted (taken from the published study14

) divided

by BSA, has reported to be the best intraoperative predictor of PPM by various studies37

. Our

reports showed that the prediction rate of PPM by intraoperative TEE was significant with

56.25% sensitivity and 100% specificity. The projected IOA had a good direct correlation with

the IOA measured by intraoperative TEE after valve implantation.

69

LIMITATIONS OF

THE STUDY

70

LIMITATIONS OF THE STUDY

Although the echocardiographic characteristics of CHVP comply with the

guidelines recommended by ASE, we acknowledge that there are certain limitations to our study.

The study subjects were selected from a single tertiary center. Probably a multicenter study

involving diverse ethnic population having different height, weight and BSA may be better in

generalizing the echocardiographic characteristics of the valve. Although we obtained

satisfactory results of performance of CHVP in 40 patients, a more conclusive evidence will be

obtained by conducting the study in large number of subjects. We did not analyzed the

interobserver and intraobserver variability in our patients. Even though the peak velocity and

mean gradients were within acceptable limits in the intraoperative period, we measured flow

independent parameters because variable preloading conditions, inotropic states, heart rate and

hemodilution may prevail in the post-CPB period that may confound the results. In the

postoperative period (after 48 hours and after 3 months), we limited the Doppler evaluation to

the measurement of velocity and gradients. Since there are no established reference values for

intraoperative TEE Doppler parameters of CHVP, we relied on the published TTE data to

compare our results. The projected IOA of our patients was also calculated from the published

TTE study.

71

CONCLUSION

72

CONCLUSION

CHVP of sizes ranging from 19 mm to 27 mm were implanted at aortic position

in the study participants and all the prosthesis were functioning well. On evaluation with 2D

echo, color Doppler and spectral Doppler, we found that TEE features of CHVP were compliant

with the criteria set by the ASE to describe a normal functioning aortic valve prosthesis. Aortic

CHVP can be adequately evaluated by intraoperative TEE.

1. The clinical parameters and echocardiographic examination suggests that the CHVP implanted

at aortic position provides satisfactory hemodynamic conditions after termination of CPB.

2. On 2D inspection, CHVP was found to have a stable valve seating and adequate occluder

motion. Color Doppler examination revealed the presence of two physiological jets (closing jet

and washing jet) in mid-esophageal views.

3. We evaluated both flow-dependent parameters (peak velocity, peak gradient and mean

gradient) and flow-independent parameters (AT, ET, AT/ET ratio, DVI and EOA) in all patients

in the intraoperative period. The Doppler parameters of CHVP were compliant with the ASE

recommendations for a normally functioning aortic valve prosthesis. Peak velocity was more

than 3 m/sec and mean gradient was more than 20 mm Hg in only one patient. Moderate PPM

(as assessed using IOA) was detected in nine (23%) patients, all of them implanted with either

size 19 mm or 21 mm prosthesis. All of them were receiving one or two inotropes in the post-

CPB period at the time of measurement of Doppler gradients. Although 2 patients in 19 mm

group had DVI of 0.29, AT and IOA in them were normal.

4. When the Doppler parameters of different sizes of CHVP were compared, the peak velocity,

peak gradient and mean gradient had strong inverse correlation with the size of the prosthesis

73

whereas the EOA and IOA had direct strong correlation with the valve size. The other

parameters such as AT, AT/ET and DVI did not appear to have any significant correlation with

the valve size.

5. The flow dependent Doppler parameters (peak velocity, peak gradient and mean gradient)

obtained by intraoperative TEE did not differ significantly from those obtained on 3rd

postoperative day and after 3 months of surgery. The TTE1 (48 hours after surgery) Doppler

parameters had a significant direct correlation and TTE2 (3 months after surgery) Doppler

parameters had a good direct correlation with the intraoperative TEE Doppler parameters

suggesting that the values of Doppler parameters obtained on intraoperative TEE predict the

postoperative values of Doppler parameters on TTE examination.

6. The published TTE data of St. Jude medical bileaflet prosthesis and intraoperative TEE

Doppler parameters of CHVP of same sized valves were comparable except for the EOA of

smaller valves (19 mm, 21mm and 23 mm).

7. We tested the specificity, positive predictive value, sensitivity and negative predictive value of

intraoperative TEE towards detecting the presence of PPM (when the predicted size of CHVP

was implanted, as well as when the predicted size was not implanted). Intraoperative TEE has

100% specificity in detecting absence of PPM. The positive predictive value of 100% suggests

that when the presence of PPM was predicted, it turned out to be true. However, the sensitivity

and negative predictive value were 56.25 % and 77.42% respectively suggesting that the role of

intraoperative TEE in detecting the presence of PPM where the predicted CHVP size was not

implanted is less. The projected IOA correlates well with IOA estimated by intraoperative TEE.

74

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85

ANNEXURES

86

ABBREVIATIONS

2D – two dimensional

ARE – Aortic root enlargement

ASE – American Societyof Echocardiography

AT – Acceleration time

AT/ET – Acceleration time/ejection time

AVR – Aortic valve replacement

BMI – Body mass index

BSA – Body surface area

CE- Continuity equation

CHVP- Chitra heart valve prosthesis

CPB- Cardio-pulmonary bypass

CWD - Continuous wave Doppler

DVI- Doppler velocity index

EOA- Effective orifice area

IOA- indexed orifice area

LA- Left atrium

LV- Left ventricle

LVEF – Left ventricular ejection fraction

LVID –Left ventricular internal diameter

LVOT – Left ventricular outflow tract

ME AV LAX - Mid-esophageal aortic valve long axis view

ME LAX – Mid-esophageal long axis view

NYHA – New York Heart Association

PPM- Patient prosthesis mismatch

PWD - Pulse wave Doppler

SCA – Society of Cardiovascular Anesthesiologists

SCTIMST- Sree Chitra Tirunal institute for medical sciences and technology

TEE- Trans-esophageal echocardiography

87

TG 2C – Transgastric two chamber view

TG 5C – Transgastric five chamber view

TG LAX – Transgastric long axis view

TTE – Transthoracic echocardiography

TTE1 – Transthoracic echocardiography- 48 hours after surgery

TTE2 – Transthoracic echocardiography- 3 months after surgery

TTK - T. T. Krishnamachari (founder of TTK Conglomerate)

VTI – Velocity time integral

USA – United states of America

88

Consent form

Title of the study:

“INTRAOPERATIVEHEMODYNAMIC PERFORMANCE AND ECHOCARDIOGRAPHIC

CHARACTERISTICS EVALUATION OF CHITRA HEART VALVE PROSTHESIS IN THE

AORTIC POSITION USING TRANSESOPHAGEAL ECHOCARDIOGRAPHY”

Study numbers: We request you to participate in the study wherein we are planning to evaluate

intraoperative echocardiographic characteristics of Chitra heart valve prosthesis in the aortic

position using Trans-esophageal echocardiography. We hope to include 40 people from this

hospital in this study.

What is Aortic valve?

Heart valves lie at the exit of each of your four heart chambers and maintain one-way blood flow

through your heart. The four heart valves make sure that blood always flows freely in a forward

direction and that there is no backward leakage. Aortic valve is one of the heart valves lying

between left ventricle and aorta.The aortic valve normally opens and closes to let the blood pass

away from the left side of the heart to other parts of the body.

What is Aortic valve replacement?

Aortic valve replacement is a open heart surgery to replace the aortic valve.If the aortic valve

does not open or close correctly due to disease, blood may not flow as it should. Aortic valve

disease can develop before birth (congenital) or can be acquired sometime during one's lifetime.

Hence diseased heart valve should be replaced with an artificial one.

What is Trans-esophageal echocardiography?

Trans-esophageal echocardiography or TEE is a test that uses sound waves to create high-quality

moving pictures of the heart and its blood vessels. This can pin point the problematic areas of the

heart and helpful in assessing function of heart valves before and after valve replacement

surgery. TEE involves a flexible tube (probe) with a transducer at its tip. Your doctor will guide

the probe down your throat and into your esophagus (the passage leading from your mouth to

your stomach). This will be done when you are under anesthesia and will not cause any

discomfort. This approach allows your doctor to get more detailed pictures of your heart because

the esophagus is directly behind the heart.

What is the role of Trans-esophageal echocardiography in valve replacement surgery?

Trans-esophageal echocardiography (TEE) is a useful monitoring tool during cardiac surgery.

American society of Anesthesiology and Society of cardiovascular Anesthesiologists have

strongly recommended the use of intraoperative TEE in adult patients undergoing valve

replacement to confirm and refine the preoperative diagnosis, to detect new or unsuspected

pathology, to adjust the anesthetic and surgical plan accordingly, and to assess the results of the

surgical intervention. This can pin point the problematic areas of the heart and helpful in

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assessing function of heart valves before and after valve replacement surgery. This is of great

help in assessing the heart function during the operation.

How is Trans-esophageal echocardiography performed?

This will be done when you are under anesthesia and will not cause any discomfort. Your doctor

will insert the lubricated probe into your mouth. He or she will then gently guide it down your

throat into your esophagus. Your esophagus lies directly behind your heart. During this process,

your doctor will take care to protect your teeth and mouth from injury.

What are the risks and side-effects?

We do not expect that our study will cause any injury to you because our study protocol is a part

of routine intraoperative TEE examination. You will be under the effect of anesthesia while the

test is being performed, thus you are unlikely to experience any discomfort.

Why are we doing this study?

The purpose of our research is to find out the hemodynamic characteristics of Chitra heart valve

placed in aorticposition with the help of Trans-esophageal echocardiography. This research will

involve collection of the data obtained during intraoperative period for the purpose of research

and publication regarding the study of hemodynamic profile of the Chitra heart valve prosthesis.

Can you withdraw from this study after it starts?

Your participation in this study is entirely voluntary and you are also free to decide to withdraw

permission to participate in this study. If you do so, this will not affect your usual treatment at

this hospital in any way.

What will happen if you develop any study related injury?

We do not expect any injury to happen to you but if you do develop any side effects or problems

due to the study, these will be treated at no cost to you. We are unable to provide any monetary

compensation, however.

Will you have to pay for the study? No.

Will your personal details be kept confidential?

Your personal details will be kept confidential. The result of this study will be published in a

medical journal but you will not be identified by name in any publication or presentation of

results.

If you have any further questions, please ask:

Dr. M.S.Saravana Babu, Senior Resident, Department of Anaesthesia (Ph No: 8589086898)

Dr.Rupa Sreedhar, Professor, Department of Anaesthesia.

Dr. Shrinivas Gadhinglajkar, Professor, Department of Anaesthesia.

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DECLARATION

I , ________________________________________________ ,

Participant’s name: Date of Birth / Age (in years) son / daughter of

___________________________________ (Please tick boxes) •declare that I have read the

above information provide to me regarding the study :

“Intraoperative hemodynamic performance and echocardiographic characteristics

evaluation of Chitra heart valve prosthesis in the aortic position using transesophageal

echocardiography”.

And have clarified any doubts that I had. [ ]

I also understand that my participation in this study is entirely voluntary and that

I am free to withdraw permission to continue to participate at any time without

affecting my usual treatment or my legal rights [ ]

I understand that the study staff and institutional ethics committee members will

not need my permission to look at my health records even if I withdraw from the

trial. I agree to this access [ ]

I understand that my identity will not be revealed in any information released to

third parties or published [ ]

I voluntarily agree to take part in this study [ ]

I received a copy of this signed consent form [ ]

Name:

Signature:

Name of witness:

Relation to participant:

(Person Obtaining Consent)

I attest that the requirements for informed consent for the medical research project

described in this form have been satisfied. I have discussed the research project with the

participant and explained to him or her in nontechnical terms all of the information

contained in this informed consent form, including any risks and adverse reactions that

may reasonably be expected to occur. I further certify that I encouraged the participant to

ask questions and that all questions asked were answered.

________________________________ ___________________

Dr. M.S.Saravana Babu,

Senior Resident, CVTA,SCTIMST.

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OBSERVATION CHART

Intraoperative hemodynamic performance and echocardiographic characteristics evaluation of

Chitra heart valve prosthesis in the aortic position using transesophageal echocardiography.

Name of the patient: Weight (kg):

Age: Height (cm):

Sex: Body surface area (kg/ cm2):

Hospital number:

Diagnosis and surgery: Date of surgery:

Preoperative features:

NYHA: Heart rate and rhythm:

Transthoracic echo report:

Preoperative medication:

Intraoperative echocardiographic observations

TEE findings before CPB:

Parameter Echo finding

LVEF (%)

LVIDD (mm)

LVIDS (mm)

LV posterior wall thickness systolic/ diastolic (mm)

Septal wall thickness systolic/ diastolic (mm)

Aortic valve examination:

AVA (cm2)

AV pressure gradient (peak systolic & mean) mmHg

LA size

Calcification of annulus

Grade of AR

Associated Mitral stenosis or regurgitation (grade)

Associated TR/PR

Any other

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CPB details:

CPB duration (minutes)

Aortic cross-clamp time (minutes)

Inotropes (mcg/ kg/ min)

1.

2.

Other drug infusions

1.

2.

Number of weaning attempts

Surgical details:

Size of Aortic valve prosthesis

Aortic root augmentation

Orientation anatomical/anti-anatomical

Hemodynamic and TEE findings after weaning from CPB

Hemodynamic

Heart rate (beats/ minute)

BP systolic /diastolic/mean during assessment

1.

2.

Rhythm

Cardiac Pacing, type

Filling pressures (mmHg)

Other

LVEF (%)

LVIDD (mm)

LVIDS (mm)

Grade of MR or MS

TEE Observations on CHVP examination

2D examination of CHVP

Motion of occluder disc (free/ restricted)

Angle of opening (degree)

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Motion of CHVP sewing ring (absent/ present)

Any characteristic appearance

Color Doppler examination of CHVP

Central leakage regurgitant jet (grade and number)

Regurgitant jet at contact between disc and stent (grade,

number)

Paravalvular regurgitant jet grade (before protamine)

Paravalvular regurgitant jet grade (After protamine)

Spectral Doppler examination of CHVP

Peak velocity (cm/s)

Peak systolic gradient (mmHg)

Mean gradient (mmHg)

Contour of the jet velocity

Acceleration time (ms)

Ejection time (ms)

AT/ET

VTI of LVOT (cm)

VTI of CHVP (cm)

DVI

Diameter of LVOT (cm)

LVOT area (cm2)

EOA of CHVP (cm2)

EOAi of CHVP (cm2/ m

2)

Stroke volume (ml/ min)

Heart rate (beats/ minute)

Blood pressure(S/D mm hg)

Cardiac output (lit/ min)

Cardiac Index (lit/ min/ m2)

PPM

Size of aortic root (mm)

Any other observations

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Postoperative Transthoracic echocardiographic observations

3rd

Post-operative Day (48 hours after surgery) TTE1 Date:

CHVP Size

LVEF (%)

LVIDD (mm)

LVIDS (mm)

LV posterior wall thickness systolic/ diastolic (mm)

Septal wall thickness systolic/ diastolic (mm)

Peak velocity (cm/s)

Peak systolic gradient (mmHg)

Mean gradient (mmHg)

Heart rate (beats/ minute)

MR/AR/TR/PR

Post-operative follow up (3 months after surgery) TTE2 Date:

CHVP Size

LVEF (%)

LVIDD (mm)

LVIDS (mm)

Peak velocity (cm/s)

Peak systolic gradient (mmHg)

Mean gradient (mmHg)

Heart rate (beats/ minute)

MR/AR/TR/PR

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TECHNICAL ADVISORY COMMITTEE APPROVAL

100

INSTITUTIONAL ETHICS COMMITTEE APPROVAL

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PLAGIARISM ORIGINALITY REPORT

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MASTER CHART

PROJECTED EOA PROJECTED VALVE SIZE Intra-Op Intra -Op Mean

CHVP # IOA VALVE Prediction EOA Projected IOA

placed by PLACED post cpb TEE from previous study BSA mean IOA x BSA

TEE Doppler Y/N > 0.85 C/INC of placed CHVP

1 1.51 1.28 21 19 0.94 N INC 19 1.1 1.51 0.73

2 1.38 1.2 21 19 0.81 N C 19 1.1 1.38 0.8

3 1.52 1.3 21 19 0.78 N C 19 1.1 1.52 0.73

4 1.59 1.35 21 19 0.93 N INC 19 1.1 1.59 0.7

5 1.64 1.4 23 19 0.92 N INC 19 1.1 1.64 0.68

6 1.59 1.35 21 19 1 N INC 19 1.1 1.59 0.7

7 1.72 1.46 23 19 0.81 N C 19 1.1 1.72 0.64

8 1.58 1.34 21 19 0.79 N C 19 1.1 1.58 0.64

9 1.78 1.51 23 21 1.1 N INC 21 1.38 1.78 0.78

10 1.7 1.49 23 21 0.8 N C 21 1.38 1.7 0.81

11 1.61 1.37 21 21 1.1 Y C 21 1.38 1.61 0.86

12 1.69 1.44 21 21 0.99 Y C 21 1.38 1.69 0.82

13 1.82 1.55 25 21 0.73 N C 21 1.38 1.82 0.76

14 1.67 1.41 23 21 0.82 N C 21 1.38 1.67 0.83

15 1.78 1.51 23 21 0.94 N INC 21 1.38 1.78 0.76

16 1.73 1.47 23 21 0.84 N C 21 1.38 1.73 0.8

17 1.71 1.45 21 21 0.93 Y C 21 1.38 1.71 0.81

18 1.74 1.47 21 21 0.95 Y C 21 1.38 1.74 0.8

19 1.43 1.22 21 21 1.16 Y C 21 1.38 1.43 0.96

20 1.93 1.64 25 21 0.8 N C 21 1.38 1.93 0.72

21 1.69 1.44 21 21 1 Y C 21 1.38 1.69 0.82

22 1.48 1.26 21 21 1.08 Y C 21 1.38 1.48 0.93

23 1.82 1.55 23 21 0.92 N INC 21 1.38 1.82 0.76

24 2 1.7 23 23 1.3 Y C 23 1.76 2 0.88

25 1.7 1.44 23 23 1.12 Y C 23 1.76 1.7 1.03

26 1.89 1.61 23 23 1.04 y C 23 1.76 1.89 0.93

27 1.72 1.46 23 23 1.2 Y C 23 1.76 1.72 1.02

28 1.62 1.38 23 23 1.08 Y C 23 1.76 1.62 1.08

29 1.59 1.35 23 23 1.2 Y C 23 1.76 1.59 1.1

30 1.52 1.29 21 23 1.3 y C 23 1.76 1.52 1.15

31 1.79 1.52 23 23 1.2 Y C 23 1.76 1.79 0.98

32 1.69 1.44 23 23 1.2 Y C 23 1.76 1.69 1.04

33 1.57 1.33 23 25 1.3 y C 25 2.32 1.57 1.48

34 1.81 1.54 23 25 1.1 y C 25 2.32 1.81 1.28

35 1.87 1.59 25 25 1.27 Y C 25 2.32 1.87 1.24

36 1.62 1.38 23 27 1.3 Y C 27 2.33 1.62 1.43

37 1.91 1.62 25 27 1.2 Y C 27 2.33 1.91 1.22

38 1.61 1.37 23 27 1.49 Y C 27 2.33 1.61 1.45

39 1.65 1.4 23 27 1.5 Y C 27 2.33 1.65 1.41

40 1.73 1.47 23 27 1.4 Y C 27 2.33 1.73 1.35

PATIENTno CHVP Placed

RECOMMENDED

0.85 x BSA RECOMMENDEDBSA