Aortic Atresia With Ventricular Septal Defect and Normal-Sized Left Ventricle Mimicking Truncus Arteriosus

Aortic atresia is typically associated with a hypoplastic left ventricle and mitral valve. Rarely, the left ventricle is normal-sized with a concomitant unrestrictive ventricular septal defect (VSD), which can resemble truncus arteriosus when the ascending aorta is rudimentary.

A term infant with an antenatal diagnosis of truncus arteriosus was delivered uneventfully. Initial echocardiography revealed balanced ventricles, an unrestrictive VSD, and a single outlet with a dominant arterial trunk giving rise to both pulmonary arteries and continuing to the descending aorta but with an unusual craniobrachial branching pattern. Computed tomography (CT) additionally showed narrowing of this arterial trunk proximal to the descending aorta. The infant deteriorated rapidly despite intravenous prostaglandin and dopamine infusion. Emergency surgery was performed to establish an unobstructed aortic arch. Postoperatively, the infant required extracorporeal membrane oxygenation and developed multiorgan failure. Given the poor prognosis, comfort care was adopted and the infant died. Retrospective review of the echocardiography and CT angiogram suggested aortic atresia with a rudimentary ascending aorta and severe coarctation. The presumed arterial trunk was in fact the dilated pulmonary artery connected to the descending aorta through the ductus arteriosus.

Aortic atresia with an unrestrictive VSD and a normal-sized left ventricle can mimic truncus arteriosus. Timely differentiation is pivotal to improving outcomes.