Download - Patent Ductus 2

8/4/2019 Patent Ductus 2

1/80

Patent Ductus Arteriousus


2/80

History

In 1593 Giambattista Carcano described ductusarteriosus in book great cardiac vessels of the fetus

Leo bottani falsely associated with ductus


3/80


4/80

Anatomy

Normal fetal vascular channel between aorta andpulmonary artery.

The pulmonary end is located to left of bifurcation of

pulmonary trunk Aortic end is just beyond the origin of left subclavian

artery

With a right aortic arch, the ductus arteriosus may be

on the right, joining the right pulmonary artery andthe right aortic arch just distal to the right subclavianartery


5/80

Introduction


6/80


7/80

microscopic structure of the ductus arteriosus differs

the media of the ductus arteriosus consist largely oflayers of smooth muscle arranged spirally in both

leftward and rightward directions The intimal layer of the ductus arteriosus is thicker

than that of the adjoining arteries and contains anincreased amount of mucoid substance


8/80

Embryology


9/80

Physiology

Role in the Fetus

6 weeks of gestation, the ductus arteriosus isdeveloped sufficiently to carry most of the right

ventricular output The right ventricle ejects about two thirds of

combined ventricular output

ductus arteriosus permits flow to be diverted away

from the high-resistance pulmonary circulation


10/80

Normal Postnatal Closure

closure of the ductus arteriosus is effected in twophases

Immediately after birth, contraction and cellular

migration of the medial smooth muscle in the wall ofthe ductus

resulting in functional closure

commonly occurs within 12 hours after birth


11/80

Normal Postnatal Closure

The second stage usually is completed by 2 to 3weeks

produced by infolding of the endothelium, disruption

and fragmentation of the internal elastic lamina replacement of muscle fibers with fibrosis

permanent sealing of the lumen to produce theligamentum arteriosum


12/80

mechanisms responsible for the initial postnatalclosure of the ductus arteriosus are not fullyunderstood

increase in pO2, as occurs with ventilation after birth,constricts the ductus arteriosus

prostaglandins play an active role in maintaining theductus arteriosus in a dilated state

PGE1, PGE2, and PGI2 dilate isolated ductusarteriosus strips or rings from term fetal lambs


13/80

At birth, the placental source is removed, and themarked increase in pulmonary blood flow allowseffective removal of circulating PGE2


14/80

INCIDENCE OF PDA

increased dramatically over the last two decades

improved survival rate of premature infants

incidence is approximately 0.02 to 0.04 percent

among term infants born at sea level slight female predominance

incidence is as high as 60 percent in infants bornbefore 28 weeks gestation


15/80

Clinical History

The diagnosis of PDA canot be made at birth

The murmur emerges after few days as thepulmonary vascular resistance falls

History of prematurity is very important. Premature babies with respiratory distress tend to

have large shunts

PDA is moe common in females with a ratio of 2:1


16/80

Family history is important , as it tends to recur insiblings

Rubella infection to mother during the first trimester

is a common cause maternal coxsackie virus infection is another cause

Low birth weight is common, even in small shunts

More common in children born in October toJanuary


17/80


18/80


19/80


20/80

Another interesting point is the relation to thealtitude the patient was born


21/80

Small Ductus Arteriosus

the resistance to flow across the ductus arteriosus ishigh

only a small left-to-right shunt develops

Pulmonary blood flow is increased only minimally left ventricular failure does not occur

Most of the infants are asymptomatic

Murmur is detected on routine physical examination.


22/80

Moderate Ductus Arteriosus

In infants a moderate shunt produces symptoms ofheart failure

Poor feeding, irritability, and tachypnea are present

symptoms ordinarily increase until about the secondto third month


23/80

Large Ductus Arteriosus

Infants with a large PDA are invariably symptomatic

They are irritable, feed poorly, fail to gain weight andsweat excessively

They have increased respiratory effort andrespiratory rates

prone to develop recurrent upper respiratoryinfections and pneumonia

symptoms indicative of severe left ventricular failurewith pulmonary edema may occur early in infancy


24/80

Patients with reversed shunt

Small number of cases

High pulmonary vascular resistance, from infancy

Effort dyspnea is the most common symptom

Symptoms of left ventricular failure are absent Hoaseness of voice may be present.

Cyanosis may be overlooked.

There is marked leg fatigue and absence of dyspnea Rarely patients may have swelling and pain in lower

limbs.


25/80

Physical apperance

Physical underdevelopment due to a large shunt

Maternal rubella syndrome: cataract, deafness andmental retardation

Rocker bottom feet and loose skin is present intrisomy 13

In this syndrome assosiated VSD is usually present


26/80

Examination

Differential cyanosis and clubbing is pesent in shuntreversal

It can be brought out by exersise or a warm water

bath Useful to have patient sit with hands and feet

together.


27/80


28/80

Arterial pulse

A wide pulse pressure is present

Pulse has a brisk rise, single peak and rapid collapse

Diastolic pressure is low, systolic is high

The peripheral pulses are bounding If the shunt is small or if there is pulmonary

hypertension the bounding pulse is absent


29/80

JVP

JVP is normal in small shunts

In patients of cardiac failure the jvp is elevated andprominent A and V waves are present

Prominent A waves are present in high pulmonaryresistance


30/80

Auscultation

The classic murmur of uncomplicated PDA rises topeak in latter systole

Continues without interruption through the second

heart sound Declines in intensity in diastole

a silent interval may be present towards the end ofdiastole


31/80

Continious murmur

A small duct results in a soft , high frequencycontinuous murmur

A larger duct causes a loud noisy machinery murmur

Loud murmur becomes soft if there is narrowing ofthe duct.

The murmur is dependent on the pressure differencebetween aorta and pulmonary artery


32/80

Progression of murmur

As the diastolic pressure of pulmonary arteryincreases the patient is left with a holosystolicmurmur

As pulmonary hypertension progresses further thesystolic component also disappears

Right to left flow across PDA does not have amurmur

With increasing PH Gibson murmur is abolished Findings of pulmonary hypertension are present


33/80

Newborn

In newborns the classic murmur is absent

Only a soft systolic murmur may be present

this is due to high pulmoary pressures

However the signs of cardiac failure are present


34/80

Second heart sound

Paradoxical spitting is present in patients of large leftto right shunts

due to Prolonged LV ejection and short RV ejection

Difficult to detect on auscultation With shunt reversal the second heart sound is closely

split with loud pulmonary component


35/80

ECG

Small ductus ECG may be normal

Variation in ecg depend on the volume overload ofLV and pressure overload of RV

Usually have sinus rhythm P waves are notched, bifid and prolonged

s/o left atrial enlargement

With development of pulmonary hypertension signsof biatrial enlargement are present


36/80

PR interval is prolonged in 10 to 20 percent ofpatients

QRS axis is normal

Volume overload of left ventricle results in deep swaves in v1, tall r waves I v5 to v6, deep q waves andtall t waves

A large shunt with pulmonary hypertension results

in features of biventricular hypertrophy Large equidiphasic complexes are present from v1 to

v6


37/80

ECG in right to left shunt

In PDA with right to left shunt peaked narrow rightatrial P waves appear in 2,3,and v1

QRS axis shows right axis deviation

Right ventricular hypertrophy R waves in v5, v6 remain tall bur the q waves and the

tall t waves disappear


38/80

X ray chest

Variation in XRAY depend on size, duration anddirection and pulmonary pressures

The ductus may be seen as a convexity between aorta

and pulmonary artery In older patients calcium may be depoisted


39/80


40/80

Left to right shunt causes increase in pulmoaryplethora

Pulmonary trunk and main branches are dilated

Ascending aorta is enlarged in adults LA and LV are enlarged

RA and RV dilatation occurs when pulmonaryhypertension is present


41/80

Right to left shunt

RV is hypertrophied

Pulmonary trunk and main branches are dilated

Peripheral vasculature is reduced

Ascending aorta is normal sized Patients who have shunt reversal have larger hearts

Both RV and LV enlargement is seen


42/80

Echocardiography

A complete echocardiographic evaluation of the PDAincludes

two-dimensional imaging of the ductus,

evaluation of the degree of shunting at the ductus,and

evaluation of pulmonary artery pressure usingDoppler echocardiography


43/80

Anatomic assessment

Most commonly, the ductus is imaged in theparasternal and suprasternal notch views

In the high parasternal short axis view, with the

transducer oriented leftward toward the pulmonaryartery bifurcation, the ductus can be imagedcoursing between the pulmonary artery and thedescending aorta

Absolute quantification of its diameter is the bestway to determine its presence or absence


44/80


45/80

In the suprasternal notch window, the ductus arisesfrom the descending aorta at the level of the leftsubclavian artery, and courses anteriorly to join thepulmonary artery


46/80


47/80


48/80

Color flow mapping is particularly helpful in thesetting of a small PDA,

Determination of the origin of the retrograde flowinto the pulmonary artery using two-dimensionalimaging as well as color flow mapping is crucial toavoid confusion of the patent ductus with otheraortopulmonary shunts


49/80


50/80

The Size of the Left Atrium Left atrial (LA) enlargement signifies increased

pulmonary venous return because of left-to-rightductal shunting


51/80


52/80

Left Ventricular Size

This will enlarge as cardiac output increases withboth increased pulmonary venous return and with

increased diastolic run-off Descending Aortic Flow in Diastole

The presence of a significant ductal shunt resultsin diastolic run-off to the pulmonary circulation


53/80


54/80

Left Pulmonary Artery Diastolic FlowVelocity

This is higher with large left-to-right

shunts. Values less than 15cm/sec are seen whenthe duct is closed


55/80


56/80


57/80

Hemodynamic assessment

The pulmonary to systemic flow ratio (Qp:Qs) can bedetermined echocardiographically

When the pulmonary artery pressure is lower thansystemic arterial pressure, there is continuous left-to-right shunting demonstrated.

The velocity of flow across the ductus, measured byeither pulsed or continuous wave Doppler,

can be translated into the gradient between theaorta and the pulmonary artery


58/80


59/80

When the pulmonary artery pressure is equal tosystemic pressure, pulsed Doppler within the ductusdemonstrates systolic right-to-left shunting, withdiastolic left-to-right flow within the vessel

Cardiac Catheterization


60/80

Cardiac Catheterization

Color Doppler flow mapping is generally as sensitiveas cardiac catheterization for detecting even a smallPDA

In children with pulmonary hypertension,determining the exact location of the shunt can bedifficult

Right heart catheterization alone usually suffices to

confirm the diagnosis an additional lesion such as ventricular septal defect

is suspected


61/80

An increase of pulmonary arterial blood oxygencontent of >0.5 mL/dL or a saturation increase of>4% to 5% from that in right ventricular bloodindicates a significant left-to-right shunt at the

pulmonary arterial level

An increase in oxygen saturation in pulmonaryarterial blood is not diagnostic of a PDA, but may be

present in lesions such as aortopulmonary windowor a high ventricular septal defect


62/80


63/80

a small communication, pulmonary arterial bloodpressures are normal, but systemic arterial pulsepressure may be slightly widened

a moderate-sized defect,

1. pulmonary arterial systolic, diastolic, and meanblood pressures may be slightly elevated.

2. Systemic arterial diastolic blood pressure falls,

3. whereas systemic arterial pulse pressure increases

l h h d


64/80

large shunt hemodynamics

pulmonary and systemic arterial pressures are equal, left atrial mean pressure may be increased substantially,

and a prominent V wave is seen.

Left ventricular end-diastolic pressure may be elevated,

a diastolic pressure gradient between the left atrium andleft ventricle is demonstrated.

A small systolic pressure difference between the left

ventricle and aorta is also encountered

Angiography


65/80

Angiography

it is the most effective test for defining the anatomyof the PDA

Contrast medium is injected into a catheter passedthrough the PDA into the aorta from the pulmonaryartery or into the aorta retrogradely from thefemoral artery

PDA usually is widely dilated, and the ductus

narrows down at the pulmonary arterial end


66/80

the lateral projection, or occasionally the left anterioroblique projection, demonstrates the anatomy mostclearly

The AP camera can be positioned in the rightanterior oblique caudal position to demonstrate thePDA

selective descending aortography is essential in

patients of VSD or ASD to demonstrate PDA


67/80

M i R I i


68/80

Magnetic Resonance Imaging

simpler techniques such as two-dimensionalechocardiography Doppler evaluation accuratelydefine the anatomy

These studies can be of use in adolescents or adultswith poor echo windows

Velocity-encoded cine MRI imaging for estimation ofleft-to-right shunting may have additional clinical

utility


69/80

P t l


70/80

Percutaneous closure

A variety of devices have been used for percutaneousclosure of a PDA

It is the standard of care in most patients

Exception in premature and small infants with largeshunts

Have been available for last 20 years

C il


71/80

Coils

Stainless steel Gianturco coils Earlier used for AV malformations

For duct closure the PDA should be less than 2 mm

in diameter, long to accommodate loops and shouldhave sufficient aortic ductal diverticulum

The coils are deployed in a retrograde fashion fromthe aorta

Coil embolisation is a dangerous complication Modified coils with release mechanism are available


72/80


73/80


74/80

Multiple coils are used for large PDA PDA closure rate are around 95 to 100% at 2 years

Residual shunt causes haemolysis

Modifications available areGiantruco-grifika vascular occlusion device

Nit occlud PDA occluder

D t l d d i


75/80

Duct occluder device

AMPLATZ duct occluder is only device which is FDAapproved

Cone shaped device

Antegrade venous approach Delivery cable- release notch

98% closure at 6 months in large PDA

Complications are left pulmonary artery stenosis,

aortic coarctation

Small ducts are avoided


76/80


77/80


78/80

Follow up


79/80

Follow up

Anticoagulation for 6 months Endocarditis prophylaxsis

Follow up 2d echo after 6 months


80/80

Thank you