Tetralogy of Fallot with Absent Pulmonary Valve: A Single-center Experience

Tetralogy of Fallot (TOF) with absent pulmonary valve (APV) is a rare congenital heart disease with a 2% incidence among patients of TOF. The main hallmark of the disease is the presence of a rudimentary pulmonary valve or a ridge-like structure with pulmonary regurgitation and a hugely dilated main pulmonary artery. It has a perinatal mortality of 14%–64%, depending on the severity of the disease. Surgical correction is done urgently in severely symptomatic patients, whereas surgery can be delayed in asymptomatic or mildly symptomatic patients. In the last 2 years (July 2021–June 2023) in our single tertiary care center, five patients of TOF with APV with varying severity have been documented. Among these five patients, two patients had cyanosis and three patients had recurrent cough and cold during childhood. Two patients were diagnosed during health screening. One newborn had respiratory distress due to compression of the tracheobronchial tree by a hugely dilated pulmonary artery. TOF with APV has features of both pulmonary stenosis and regurgitation, a malaligned ventricular septal defect, and a dilated pulmonary artery. The direction of the shunt depends on the severity of pulmonary stenosis. Patients with left-to-right shunt may develop pulmonary artery hypertension depending on flow and gradient across the pulmonary valve. Patients with a massively dilated pulmonary trunk obstructing the tracheobronchial tree and patients with right-to-left shunt and cyanosis usually have worse outcomes. Often, the disease is diagnosed in late childhood, particularly in mildly symptomatic and asymptomatic patients.