Pulmonary Atresia With Intact Ventricular Septum Workup

Updated: Dec 27, 2020
  • Author: John R Charpie, MD, PhD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Workup

Laboratory Studies

No laboratory blood tests help to confirm a specific diagnosis of pulmonary atresia with intact ventricular septum (PAIVS).

Pulse oximetry will demonstrate similar hypoxemia in both the upper and lower extremities.

An arterial blood gas (ABG) study is likely to show hypoxemia and hypocarbia refractory to inspired oxygen concentration, consistent with cyanotic congenital heart disease (CCHD) and a fixed right-to-left shunt.

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Imaging Studies

Electrocardiography

Electrocardiography (ECG) often reveals normal sinus rhythm, QRS axis +30° to +90°, decreased right ventricular forces, left ventricular dominance, and right atrial enlargement (proportional to the degree of tricuspid regurgitation).

In addition, ST-T wave abnormalities are common in patients with ventriculocoronary connections or coronary artery stenosis and are consistent with subendocardial ischemia.

Echocardiography and Doppler

Echocardiography and angiography are the two most important studies in diagnosis of pulmonary atresia. Two-dimensional echocardiography is diagnostic for pulmonary atresia with intact ventricular septum (PAIVS). [7] A combination of subcostal and precordial views reveals anatomic pulmonary atresia in addition to tricuspid valve and right ventricular morphology and size.

Absolute volume measurements of the right ventricle usually have limited value. Data from the Congenital Heart Surgeons Study showed that the diameter of the tricuspid valve normalized to body surface area (tricuspid valve z-value) was highly correlated with size of the right ventricular cavity. In addition, retrospective data suggest that the degree of right ventricular hypoplasia was the most important determinant in a single-ventricle versus two-ventricle repair.

In addition, color-flow and continuous-wave Doppler ultrasonographic studies reveal the degree of tricuspid regurgitation, allow the estimation of right ventricular pressure which is typically suprasystemic, and reveal restriction of the interatrial communication (uncommon).

A combination of imaging and Doppler echocardiography reveals branch pulmonary artery size and configuration (usually within reference ranges), as well as ductal patency. Echocardiographic imaging may reveal ventriculocoronary connections (coronary sinusoids) but has limited use for identifying coronary artery stenoses and right ventricular–dependent coronary circulation.

Angiocardiography

The prognosis of a neonate with PAIVS directly relates to the presence or absence of ventriculocoronary connections and right ventricular–dependent coronary circulation. Although echocardiography is diagnostic for PAIVS, angiocardiography is an important imaging modality for planning future intervention.

Right ventricular angiocardiography defines the presence or absence of ventriculocoronary connections and provides additional information about the size and morphology of the right ventricle.

Balloon occlusion aortography reveals the proximal coronary arteries and coronary arterial stenosis or interruption.

Radiography

Chest radiography usually reveals mild cardiomegaly and decreased or normal pulmonary vascular markings.

With severe tricuspid regurgitation (and a dysplastic tricuspid valve), profound cardiomegaly due to right atrial enlargement may be present.

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Procedures

Cardiac catheterization

Cardiac catheterization confirms the right ventricular pressure measurement and anatomic pulmonary valve atresia.

Ventriculocoronary connections are best delineated with cardiac catheterization.

In the rare instance of a restrictive atrial communication, a transcatheter balloon or blade atrial septostomy will maintain adequate cardiac output. Transcatheter wire puncture, laser perforation, [8] and radiofrequency-assisted balloon pulmonary valvotomy have been used as alternatives to surgical valvotomy in patients with pulmonary atresia with intact ventricular septum (PAIVS) and acceptable tricuspid valve and right ventricular size. However, despite the fact that a technically adequate valvotomy can be achieved in a high percentage of patients, catheter-related complications are not rare and maintaining patency of the ductus arteriosus is necessary for a time period as an additional source of pulmonary blood flow until right ventricular hypertrophy regresses and compliance improves.

In a retrospective study of 129 infants born with critical pulmonary stenosis or membranous PAIVS, Ronai et al found that left ventricular dysfunction following pulmonary valve balloon dilation occurred in 35% of the infants and could be severe but resolved. [9] In multivariable analysis, lower pulmonary valve z-score, preexisting moderate or severe tricuspid regurgitation, and larger right ventricular apical area were predictive of postprocedure left ventricular dysfunction, with those who had larger right ventricles at the greatest risk. [9]

See the image below.

The heart catheterization. The heart catheterization.
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Histologic Findings

Patients with pulmonary atresia with intact ventricular septum (PAIVS) can demonstrate a wide range of right ventricular myocardial abnormalities including ischemia, fibrosis, infarction, rupture, fiber disarray, spongy myocardium, and endocardial fibroelastosis. The degree of endocardial fibroelastosis inversely relates to the degree of ventriculocoronary connections.

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