Truncus arteriosus communis (TAC) is a rare congenital defect where a single arterial trunk, the “trunkus,” arises from the heart. There is a hole in the ventricular septum, and both ventricles pump their blood into this single vessel. From this common arterial trunk, both the aorta and pulmonary artery branch off. The pulmonary artery may originate as a single trunk or its right and left branches may each originate separately from the trunkus.
The defect is usually repaired within a few weeks of birth by placing a valved vascular prosthesis, known as a “conduit,” from the right ventricle to the pulmonary artery and closing the ventricular septal defect so that the left ventricle pumps blood into the aorta. The small vascular prosthesis will need to be replaced with a larger one after a few years. Typically, a homograft, which is an aorta or pulmonary artery with a valve taken from a deceased donor, is used for the transplant. Patients require lifelong cardiac monitoring.
