CPT® Code 33776

Repair of transposition of the great arteries, atrial baffle procedure (eg, Mustard or Senning type) with cardiopulmonary bypass; with closure of ventricular septal defect

The procedure described by CPT® Code 33776 involves the surgical repair of transposition of the great arteries (TGA) using an atrial baffle technique, which can be categorized as either the Mustard or Senning procedure. Transposition of the great arteries is a congenital heart defect characterized by the abnormal positioning of the aorta and pulmonary arteries. In a normal heart, the aorta arises from the left ventricle, while the pulmonary arteries originate from the right ventricle. However, in TGA, the aorta is connected to the right ventricle, and the pulmonary arteries are connected to the left ventricle. This anatomical arrangement results in a situation where oxygen-poor blood is circulated back to the body without passing through the lungs for oxygenation, while oxygen-rich blood returns to the lungs instead of being delivered to the body. This condition often coexists with other cardiac anomalies, such as ventricular septal defect (VSD) and subpulmonary stenosis. VSD is defined as an abnormal opening in the ventricular septum, allowing the mixing of oxygen-rich and oxygen-poor blood, while subpulmonary stenosis refers to a narrowing of the main pulmonary artery just below the pulmonary valve. The surgical approach to repair TGA, particularly when complicated by subpulmonary stenosis, requires careful planning and may differ significantly among patients. Access to the heart is typically achieved through a median sternotomy or thoracotomy, and the procedure involves resection of the thymus and incision of the pericardium, from which a patch graft is harvested for later use. The establishment of cardiopulmonary bypass is crucial, allowing the surgeon to cross-clamp the aorta and perform the necessary repairs. The atrial baffle procedure redirects systemic venous blood to the mitral valve while excluding pulmonary venous blood, thus correcting the flow of blood within the heart. The closure of the VSD is an integral part of this procedure, ensuring that the mixing of blood is minimized and that the heart functions more effectively post-surgery.