Truncus arteriosus is a congenital (present at birth) defect that occurs due to abnormal development of the fetal heart during the first 8 weeks of pregnancy. The heart begins as a hollow tube, and the chambers, valves, and great arteries develop throughout the first 8 weeks of pregnancy. The aorta and pulmonary artery start as a single blood vessel, which eventually divides and becomes two separate arteries. Truncus arteriosus occurs when the single great vessel fails to separate completely, leaving a connection between the aorta and pulmonary artery.
Surgical repair will be necessary; prior to surgery, though, other treatment can include medical management with medications, high-calorie feedings and nutritional supplements.
Surgical repair: usually performed after the infant is 2 weeks old, but before the blood vessels in the lungs are overwhelmed by extra blood flow and become diseased. The operation is performed under general anesthesia. During the procedure, the pulmonary arteries are detached from the common artery (truncus arteriosus) and connected to the right ventricle using a homograft (a section of pulmonary artery with its valves intact from a tissue donor). The ventricular septal defect is closed with a patch.