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Transcript of JONATHON LEIPSIC MD FRCPC FSCCT - nasci.org for TAVR... · Prosthesis Sizing for TAVR Ultimate...
JONATHON LEIPSIC MD FRCPC FSCCT
A S S I S T A N T P R O F E S S O R O F R A D I O L O G Y A N D
C A R D I O L O G Y V I C E C H A I R M A N O F R A D I O L O G Y
U N I V E R S I T Y O F B R I T I S H C O L U M B I A
MDCT for TAVR: Where We Are
Disclosures
Speaker’s bureau: GE Healthcare and Edwards LifeSciences
Research Grant- GE Healthcare
Advisory Board- GE Healthcare and Edwards LifeSciences
Equity- TC3
Aortic Stenosis
Most common valvular heart disease 2-4% of adults >65 years
In US, >50,000 surgical AVR/year for AS
Hospital mortality 9% in patients >65 years
33% of AS patients >75 years deemed not surgical candidate (Iung B, Eur Heart J, 2005)
Prognosis of symptomatic patients with severe AS is very poor
TAVR has seen rapid adoption as a minimally invasive alternative to conventional surgery
Leon MB, Smith CR, Mack M et al. N Engl J Med 2010;363:1597-607
All Cause Mortality
0 6 12 18 24
Numbers at Risk
TAVI 179 138 122 67 26
Standard Rx 179 121 83 41 12
∆ at 1 yr = 20.0%
NNT = 5.0 pts
Standard Rx
TAVI
All
-cau
se m
ort
ali
ty (
%)
Months
0
20
40
60
80
100
50.7%
30.7%
CRAIG R. SMITH, MD O N B E H A L F O F T H E P A R T N E R T R I A L
I N V E S T I G A T O R S
Transcatheter vs. Surgical Aortic Valve Replacement in High Risk Patients
with Severe Aortic Stenosis: Results From The PARTNER Trial (A)
ACC 2011 | New Orleans | April 3, 2011
0
0.1
0.2
0.3
0.4
0.5
0 6 12 18 24
TAVR
AVR
Months
348 298 260 147 67
351 252 236 139 65
No. at Risk
TAVR
AVR
26.8
24.2
Primary Endpoint: All-Cause Mortality at 1 Year
HR [95% CI] =
0.93 [0.71, 1.22]
P (log rank) = 0.62
0
0.1
0.2
0.3
0.4
0.5
0 6 12 18 24
TAVR
AVR
All-Cause Mortality Transfemoral (N=492)
Months
244 215 188 119 59
248 180 168 109 56
No. at Risk
TAVR
AVR
26.4
22.2
HR [95% CI] =
0.83 [0.60, 1.15]
P (log rank) = 0.25
Outline
Systematic approach to aortic root and annulus assessment for patients undergoing transcatheter
aortic valve implantation (TAVI)
Provide a rational approach to annular sizing with CT
Angle prediction for valve implantation
Iliofemoral artery assessment
Prosthesis Sizing for TAVR
Ultimate Goal: To displace the native aortic valve leaflets and deploy the aortic prosthesis within the
native aortic valve annulus If aortic prosthesis deployment is too high:
Aortic injury Paravalvular aortic regurgitation
Embolization of aortic prosthesis into the aorta
If aortic prosthesis deployment is too low: Mitral valve dysfunction (regurgitation, restricted motion of anterior
leaflet) Heart block
Paravalvular aortic regurgitation
Embolization of aortic prosthesis into the left ventricular cavity
Aortic Annulus
Annulus Sizing The aortic annulus is a complex 3 dimensional structure Previous anatomical studies established that the aortic
annulus is a 3-pronged coronet rather than a circular structure
It has three anchor points at the nadir of each aortic cusp
The attachment of the aortic cusps is semilunar
It extends throughout the aortic root from the left ventricle distally to the sinotubular
junction
Piazza N et al. Anatomy of the Aortic Root. Circ Cardiovascular Interventions. 2008
Elliptical Annulus
The annulus is commonly oval-shaped Reported in approximately 50% of
patients evaluated for TAVR The mean difference between coronal and sagittal measurements was 3.0
1.9 mm Oval geometry of the annulus has been
previously underappreciated on imaging but well described in the
surgical literature
Tops LF, Wood DA, Delgado V, et al. Noninvasive evaluation of the aortic root
with multislice computed tomography: implications for transcatheter aortic valve replacement.
JACC Cardiovasc Imaging 2008; 3:25 -32
Piazza et al. Anatomy of the Aortic Root. Circ Intervention 2008
Accurate measurement of the aortic annulus is
essential for determining aortic prosthesis size
Valves selected based on annular sizing, Aortic annular measurements for TAVI rely upon imaging,
traditionally by:
Transthoracic echocardiography (TTE)
Transesophageal echocardiography (TEE)
Aortic angiography
Discordance between imaging modalities is not uncommon, and the “true” annular size based upon
imaging findings can be controversial
3D aortic annular and root morphology and dimensions
ECG-gated MDCT may serve as an adjunct method for aortic annular measurement
Advantages to use of ECG-gated MDCT:
Non-invasive
Routinely performed for patients prior to TAVI
Allows for true 3D measurement of aortic valve without assumptions
Allows for concomitant assessment of aortic valve, coronary arteries, and aortoiliac system
THERE IS OFTEN DISCORDANCE BETWEEN AORTIC
ANNULAR DIMENSIONS BY MDCT VERSUS ECHO
ECG-gated MDCT observes generally larger annular sizes than either TTE or TEE
Example: Pre-procedural and peri-procedural
annular measurements vary between 17-24 mm
21 mm
24 mm
17 mm
PR
E-P
RO
CE
DU
RA
L E
VA
LU
AT
ION
P
ER
I-PR
OC
ED
UR
AL
EV
AL
UA
TIO
N
Possible reasons for ECG-gated MDCT and
echo discordance for annular sizing
1. Aortic Annular Shape: 2D assessment of the annulus
may not adequately for its elliptical (non-circular) shape
2. Aortic Annular Plane: Aortic leaflet insertions into the
annulus are not necessarily at the same level
Right coronary cusp leaflet often inserts inferior to the left
and non-coronary cusp leaflets
3. Wrong plane: 2D diameter measurement of aortic annulus
may be oblique to the true annular plane
4. Variability: Inter-observer, intra-observer and/or intra-test
variability
5. Test Quality: Suboptimal or technically difficult images
Lessons Learned
Annulus Sizing There have been a number of published methods for measurement of the
aortic annulus on MDCT.
Initial published reports had evaluated the annulus in a coronal and
sagittal fashion
Regardless of the MDCT methods used to determine the aortic annular diameter, the absolute differences between MDCT and TTE or TEE are greater than the
differences between TEE and TTE
If MDCT measures of annular diameter are employed, they may influence or modify the TAVI
strategy in a considerable number of cases: 38% of patients using long and short-axis diameters
David Messika-Zeitoun, Jean-Michel Serfaty, Eric Brochet et al. Multimodal Assessment of the Aortic Annulus Diameter: Implications for Transcatheter Aortic Valve Implantation J. Am. Coll. Cardiol., January 19, 2010; 55: 186 - 194
There are differences between ALL
MDCT Methods and Echo
MDCT “3-chamber” Projection
High correlation in annular measures between
parasternal long-axis view by TTE or 3-chamber view
by TEE and “3-chamber” plane by MDCT
“3-chamber” Projection
“3 chamber projection correlates well but leaves much of the important 3-dimensional data on the
table
Moving away from 3 chamber projections to bi-dimensional measurements of the root and basal
ring incorporating more of the root geometry
Our laboratory’s experience has observed the basal mean diameter to be the most reproducible
measurement (R=0.87)
The basal mean diameter tends to measure ~1.0-1.5 mm larger than TTE parasternal long axis
measurements
Which MDCT method is most
Reproducible?
Under review JACC interventions
Aortic Annular Sizing:
Basal mean diameter
(1) (2)
(3) (4)
The Virtual Basal Ring
Source: Leipsic et al JACC Img April 2011
Sinotubular junction
Aortic leaflets
Aortic Annulus
Aortic Annular Diameter
RC = Right coronary cusp; NC = Non-coronary cusp; LC = Left coronary cusp
Aortic Annular Sizing: Basal Ring Area-Derived Diameter
Calculation for the Area Derived Diameter
Advantages to MDCT methods Greater reproducibility
Less sensitive to minor changes in obliquity’
“3-D”
“2-D”
Integrating CT into Annular Sizing
Sizing currently based on ECHO
Nevertheless, our laboratory’s practice is to integrate 3D ECG-gated MDCT as a complementary
measurement for transcatheter aortic valve sizing At a minimum, ECG-gated MDCT annular measurements
can be employed as a “tiebreaker” if discordance between TTE and TEE
At a maximum, ECG-gated MDCT annular measurements may be considered for valve sizing
We integrate the expected 1-1.5 mm size difference between these two measurements into a new CT
based sizing criteria
What are the current ECHO based
recommendations?
26mm Valve
23mm Valve
Usually tend to oversize by at least 2mm on echocardiography
26mm Valve
23mm Valve 23mm Valve
26mm Valve
Annulus by mean Diameter on CT
Proposed “Corrected” recommendations if using the mean of the long/short axis-
allow for 1-1.5 mm larger size
Imaging modality
and sizing criteria
Valve size chosen
23mm 26mm 29mm
*TEE guided 15 23 3
†MdCT unadjusted 5 26 10
MdCT using adjusted
criteria
13 23 5
Valve sizes were chosen from the MdCT mean of the basal ring but adjusted by 1.0 mm to account for the mean difference in this measurement from TEE, hence 23mm valve for annulus ≥19.5 to ≤22.5mm, 26mm valve for >22.5 to ≤26.5mm, and 29mm valve for >26.5 to ≤29.5mm
In press JACC Interventions
TAVR Strategy Modification
Left Main Height Assessment
Important Aortic root measurements Aortic measurements vary with individual valve specifications
Medtronic Corevalve has specifications regarding the height of the sinuses, the transinus dimension and the ascending aortic
diameter
The Sapien and Sapien XT do not require specifications of the sinus height
distance between the insertion of left coronary cusp and the left coronary artery ostium is important to predict risk of LM
occlusion
Left Main Height
No criteria exist to exclude patients on the basis of the risk
of coronary obstruction, but an 11-14 mm distance cutoff range has been proposed between the coronary ostia
and the leaflet insertion
Pay attention to the distribution and burden of calcification of the aortic valve cusps
Greater concern in the setting of heavily and diffusely
calcified cusps than localized calcification
Assessing the length of the left coronary cusp and its relationship to the height of the left main coronary
ostium may provide further
Left Main Height
Coronal oblique image in an 81 year old male and a 78 year old male patient the left coronary cusp and left coronary ostium is 16.2mm and 10.0 mm respectively
ILEOFEMORAL ASSESSMENT
Vascular Access Complications
ILIOFEMORAL ACCESS
Vascular complications have been reported and are largely attributable to
the large device size and significant atherosclerosis
Initial iliofemoral assessment with single plane angiography in the cath lab
MDCT allows assessment of a greater breadth of pathologies and anatomical structures
Minimal luminal diameter
Vessel tortuosity
Burden and pattern of calcification
Extent of atherosclerosis
Other high-risk features including dissections and complex atheromas
Thorough and complete three-dimensional assessment of the iliofemoral system
Iliofemoral Access- What We Know
Circumferential and/or horseshoe calcification in association with small caliber vessels or stenotic segments is considered a contraindication to a
transfemoral approach
may not allow the artery to expand to accommodate the large-profile delivery catheter
They also may increase the risk of arterial
dissection or perforation
Currently, alternative transapical or tranaxillary approaches should be considered in these patients
85 yo female- tortuous non-calcified iliofemoral arteries
X
Variable No vascular
complication
n = 58
Vascular
complication
n = 8
P Value
Minimal lumen diameter (mean) 7.0 6.2
Minimal lumen diameter < sheath
diameter, n (%)
23 (40%) 7 (83%) 0.02
Moderate or severe calcification, n (%) 9 (15%) 5 (42%) 0.04
[
Under revision JACC In press JACC
0
5
10
15
20
25
30
35
Minor (p=.02) Major (p<0.001)
2008
2009
2010
17% of patients screened with CT declined for procedure in 2010
Angle of Deployment
The need for multiple aortograms to define this optimal orientation increases procedural time,
contrast use, and radiation exposure
CT offers the potential to reduce the need for multiple angiograms and to provide guidance in
advance of the procedure
ANGLE OF DEPLOYMENT
Many potential angles representing the appropriate native aortic valve plane
Aortic valve is typically directed in a cranial and anterior fashion with angulation to
the right Caudal angulation -right anterior oblique
(RAO) projection and cranial angulation when in the left anterior oblique (LAO)
projection Significant variations across patients
Method for Co-Axial Angle Prediction:
Similar to the evaluation of the aortic annulus, double oblique transverse/ short axis multiplanar
reconstructions are performed
Points are deposited on the most inferior aspect of the aortic sinuses then connected to form a
triangle
3D volume rendered reconstruction of the aorta is then created with the triangle in place
Reconstruction is then rotated through a series of angles
ANGLE OF DEPLOYMENT
We aim to find angiographic projections representing perpendicularity to the native valve
plane in 3 axes:
1) AP cranial-caudal without RAO or LAO angulation
2) straight RAO to LAO as needed without cranial or caudal angulation
3) LAO 300 with cranial or caudal angulation as needed.
These axes were chosen based on the preferred working angles in the catheterization lab
Gurvitch, Leipsic et al. JACC Interventions Nov 2010
Predict Co-axial Angle of Deployment
CT to Assist Valve Deployment
Gurvitch R, Wood D, Leipsic J et al. MSCT for the Determination of the Angle of Deployment for TAVR. JACC Interventions. Nov 2010
Connect the Dots
Excellent-Superior struts
align perfectly Satisfactory – Superior valve
struts project within the height of
a cell
Poor –greater than the height
of a cell.
Line of Perpendicularity- Predicted Angles
MDCT vs 3-D Angio CT for Angle Prediction
CONCLUSION
TAVR therapy has seen rapid advancements over the last 5 years
Echocardiography has been commonly used for pre-procedural assessment and provides physiologic
data
MDCT can evaluate
3D annular and aortic root morphology and dimensions
Assessment of iliofemoral access
Procedural planning- angle prediction and left main height assessment