We present a successful surgical repair of a rare variant of the common arterial trunk with unusual arrangement of the pulmonary arteries. The variant was not readily classified using either of the popular classifications for the common arterial trunk. It is appropriately described as a common arterial trunk showing aortic dominance, but with extrapericardial origin of the pulmonary arteries from the underside of the truncal arch. We also provide an account of cardiac development, which we suggest offers an accurate explanation for its morphogenesis.

A common arterial trunk with pulmonary dominance is rare. We report the use of 3D volume-rendered CT imaging to define common arterial trunk with pulmonary arterial dominance and associated abnormalities.

We report a case of a 27-day-old girl with an unusual association of crossed pulmonary arteries with common arterial trunk showing pulmonary dominance with an interruption of aortic arch between the origin of the left common carotid artery and left subclavian artery. This case highlights the potential airway-related implications of this variant pulmonary arterial anatomy in the setting of the common arterial trunk and the role of computed tomography angiography in providing not only accurate and three-dimensional visualization of complex cardiovascular anatomy, but also a comprehensive evaluation of associated airway abnormalities with great precision.

Common arterial trunk with aortic dominance has well-developed bilateral pulmonary arterial arborization without any essential major aortopulmonary collateral arteries (MAPCAs), whereas "solitary" arterial trunk is characterized by collateral arterial supply to all bronchopulmonary segments and absent pulmonary arteries. We report a term female neonate with common arterial trunk with aortic dominance with confluent pulmonary arteries with a large MAPCA as the sole blood supply to the lower lobe of the left lung. Initial diagnostic workup missed this MAPCA from the descending thoracic aorta. It was suspected during surgery due to massive left atrial return and confirmed by cardiac catheterization study in the early postoperative period and treated successfully by unifocalization. A large essential MAPCA supplying an entire lobe in the common arterial trunk with aortic dominance has not been described. It can present as heart failure and inability to wean off the ventilator in the early postoperative period following intracardiac repair. This is a case hitherto undescribed and possibly falling outside the well-entrenched classifications of the common arterial trunk and a large MAPCA could be an addition to the list of lesion modifiers. Our experience with this case underlines the importance of a thorough and open-minded approach to the initial imaging assessment of even well-described conditions.

The pulmonary dominant variant of the common arterial trunk has always been reported to be associated with aortic coarctation, or interruption of the aortic arch, along with a duct-dependent systemic circulation. This mandates a complex surgical repair with attendant high surgical mortality. We report a 23-day-old baby with a pulmonary dominant trunk with mild aortic hypoplasia but with an arch free of coarctation or interruption, who underwent successful surgical repair. In the preoperative evaluation of a common arterial trunk, pulmonary dominance may not necessarily denote an adverse risk factor when the aorta is only mildly hypoplastic.