Arterial Switch Operation

In transposition of the great arteries (TGA), the two main arteries are switched: the aorta comes off the right ventricle and the pulmonary artery comes off the left ventricle. Blood then runs in two separate loops, one that never reaches the lungs and one that never reaches the body. A baby can survive only while some mixing happens through an open ductus or a hole between the chambers, so these babies are blue within the first days or weeks of life and need surgery early. The arterial switch operation puts the arteries back where they belong. Through a median sternotomy on cardiopulmonary bypass, the aorta and pulmonary artery are cut above their valves and swapped, the coronary arteries are cut out with a button of aortic wall and sewn into the new aorta, and the new pulmonary artery is rebuilt with a patch of the baby's pericardium. It has largely replaced the older atrial switch operations (Mustard and Senning), which redirected blood inside the atria but left the right ventricle pumping to the body. Surgeons differ in how they move the coronary arteries (open "trap-door" flaps, closed techniques, or reattaching them after the new aorta is filled), and in whether they use continuous bypass or short periods of circulatory arrest. The most serious early problem is poor blood flow through a moved coronary artery, which shows up as a struggling, poorly moving heart. Others include narrowing where the new pulmonary artery was joined, bleeding and, in swollen babies, the need to leave the chest open. For the scrub, this is a newborn open-heart setup with very fine instruments and 8-0 sutures, a large pericardial patch, and long, exacting steps.