Absent Pulmonary Valve Syndrome - Prenatal Diagnosis and Postnatal Correlation with a Review of Literature

Brinda Sabu,Vidyalekshmy Ranganayaki,Tazeen Khan

doi:10.11648/j.ijcems.20210703.13

Abstract

Absent Pulmonary valve syndrome (APVS) or congenital absence of pulmonary valve is a rare conotruncal anomaly in which the pulmonary valve is absent, dysplastic or rudimentary. It can be isolated or associated with tetralogy of Fallot and has a favourable to guarded postnatal outcome according to the associations. In this case report, we discuss an interesting case of APVS with postnatal correlation. Methods: Detailed USG including fetal echocardiography was performed on an ultrasound machine using appropriate presets. The abdominal and cardiac situs were normal. Segmental evaluation of the fetal heart along with color and spectral doppler was performed. Results: The fetus had the typical features of APVS, with a dilated pulmonary artery and branches, a subaortic ventricular septal defect, overriding of the aorta, and agenesis of ductus arteriosus. There was typical to and fro flow noted on color and spectral Doppler imaging representing forward stenotic and retrograde regurgitant flow. Postnatal Echocardiogram confirmed our antenatal findings. Though the baby underwent surgical correction, he succumbed due to the effects of multiorgan dysfunction and the underlying chromosomal defect. Conclusions: A dedicated fetal echocardiography around 22 weeks can accurately diagnose the condition due to its typical features of dilated main and branched pulmonary arteries, absent /dysplastic pulmonary valves with color and spectral doppler revealing features of stenosis and insufficiency. However the outcome of fetuses in APVS with additional anomalies is guarded due to the heart defect itself, respiratory complications and associated chromosomal abnormalities.

Highlights

Absent Pulmonary valve syndrome (APVS) is a rare conotruncal anomaly in which the pulmonary valve is absent, dysplastic or rudimentary [1, 2]
APVS is classified in two categories: (a) Absent pulmonary valve with VSD known as Fallot type (b) Absent pulmonary valve with intact ventricular septum known as Non Fallot type
A systematic review of 36 articles done by Abuhamad et al in 2015 compared the postnatal outcomes, genetic testing results, and sonographic findings in 3 subtypes of tetralogy of Fallot and inferred that the survival rates in TOF with APVS is significantly less than TOF with pulmonary stenosis.[14]

Summary

Introduction

APVS is a rare conotruncal anomaly in which the pulmonary valve is absent, dysplastic or rudimentary [1, 2]. In 30% of cases, the ductus arteriosus (DA) is absent, the pulmonary annulus is stenotic allowing to and fro blood flow across the dysplastic pulmonary valve, leading to severe dilatation of the pulmonary trunk and its branches. [5] Severely dilated pulmonary arteries and associated cardiomegaly cause bronchial compression resulting in bronchomalacia. This leads to respiratory compromise at birth and chronic obstructive lung disease later in life. Accepted theory for Fallot type APVS is that agenesis of DA contribute to the aneurysmal dilatation of the main and the branched pulmonary arteries. In non-Fallot type APVS, since the DA is present, aorta and main pulmonary artery accommodate bulk of increased flow, sparing the branched pulmonary arteries. The high loss rate was related to pregnancy termination, fetal heart failure, respiratory disease and chromosomal abnormalities [9, 10]

Case Report

Findings

Discussion

Conclusion