Truncus arteriosus - Van Praagh type A3

A single arterial trunk that overrides the interventricular septum with concomitant ventricular septal defect. The right pulmonary artery originates separately from the posterior aspect of the common arterial trunk just above the valve. The left pulmonary artery is not evident. Right sided aortic arch with aberrant left subclavian artery is also noted.

Truncus arteriosus is a cyanotic congenital heart anomaly in which a single trunk supplies both the pulmonary and systemic circulation. It is almost always associated with a ventricular septal defect (VSD) to allow circulatory flow circuit completion. Another common associations include right sided aortic arch (presented here) and interrupted aortic arch.

Two classification systems were suggested for this anomaly. The most popular is Collett and Edwards system which divides it into four types (not applicable here). The modified system of Van Praagh also included also four types, the third one (type A3) described originating of only onea single pulmonary artery (usually the right) originating from the common trunk (which is the case here), while the other lung is supplied either by collaterals or by a pulmonary artery arising from the aortic arch.