Total anomalous pulmonary venous connection — formative SAQs

SAQ 1 (10 marks) — The cyanosed neonate with pulmonary oedema

Stem: A two-day-old term infant presents with severe cyanosis, grunting respirations, and poor perfusion. The chest radiograph shows a normal-sized heart with a diffuse reticulogranular pulmonary oedema pattern. An echocardiogram confirms total anomalous pulmonary venous connection with obstruction of the anomalous pathway. Outline the classification, the immediate resuscitation, and the definitive management. ^{[1] [7]}

Model answer

Classification and likely type (2 marks). Total anomalous pulmonary venous connection is classified by the Darling system into supracardiac (about fifty per cent), cardiac (about twenty-five), infracardiac (about twenty), and mixed (about five). A neonate presenting on day one or two with obstruction is most likely to have the infracardiac type, in which the pulmonary venous confluence drains via a descending vertical vein to the portal vein, inferior vena cava, or ductus venosus below the diaphragm, a long pathway that is most prone to obstruction. ^[1]

Immediate resuscitation (3 marks). The priorities are airway, breathing, and circulation. The infant is ventilated and given oxygen to lower pulmonary vascular resistance, acidosis is corrected with fluid and bicarbonate, and inotropic support is started for poor perfusion. Prostaglandin E1 is sometimes used if the circulation is duct-dependent, though its role in isolated obstructed connection is debated because the ductus is not the primary problem. A restrictive atrial septum may warrant a balloon septostomy as a bridge. Retrieval to a congenital cardiac surgical centre is urgent. ^{[7] [2]}

Definitive surgical management (3 marks). Repair is always surgical and never transcatheter, because the problem is an anomalous drainage pathway that must be re-routed. The operation anastomoses the common pulmonary venous confluence to the left atrium, closes the atrial septal defect, and ligates the anomalous vertical vein. In the obstructed neonate this is performed as an emergency in the same admission; delaying surgery while awaiting improved oxygenation is a fatal error. ^[7]

Why the atrial septum matters (2 marks). An atrial septal defect or patent foramen ovale is obligatory for survival because all pulmonary venous blood returns to the right atrium and can only reach the systemic circulation by crossing the atrial communication. A restrictive septum worsens cyanosis and systemic output, and balloon septostomy enlarges it as a bridge to surgery. ^[7]