Pulmonary Atresia with Ventricular Septal Defect

Abstract

There is no forward flow across the pulmonary valve in pulmonary atresia with ventricular septal defect (PA-VSD); right ventricular output is thorough a VSD to the LV. Pulmonary atresia may affect the pulmonary valve alone with normal size pulmonary arteries, or at the other extreme the pulmonary arteries may be severely atretic with pulmonary blood flow (PBF) carried into the distal pulmonary vasculature through numerous systemic to pulmonary arterial (SP) collaterals. Patients with PA-VSD present with either cyanosis due to low PBF or congestive heart failure due to excessive PBF through large collaterals. The murmur heard in PA-VSD is continuous due to blood flow through PDA or SP collaterals. Planning of surgical repair is determined by magnitude of SP collaterals. Surgical outcome is better when the pulmonary arteries are well developed and less favorable with severe pulmonary arterial hypoplasia and higher dependence on SP collaterals. Balloon and stent dilation of abnormal pulmonary arterial branches and collaterals may be required repeatedly in severe cases to secure unobstructed PBF.