CPT® Code 33641

The procedure described by CPT® Code 33641 involves the surgical repair of an atrial septal defect (ASD), specifically the secundum type, utilizing cardiopulmonary bypass. An atrial septal defect is a congenital heart defect characterized by an abnormal opening in the septum that separates the heart's two upper chambers, the atria. The secundum type is the most prevalent form of ASD, often referred to as an ostium secundum defect. This defect arises when the foramen ovale, a normal fetal opening in the atrial septum that allows blood to flow from the right atrium to the left atrium, fails to close after birth. The ostium secundum defect typically occurs in the mid-septal region and may extend into the fossa ovalis, which is located in the lower part of the atrial septum. The size and shape of the defect can vary significantly among patients. During the surgical procedure, the heart is accessed through a median sternotomy or an upper hemisternotomy, which involves making an incision in the chest to expose the heart. Once the heart is accessible, venous and arterial cannulas are inserted to establish cardiopulmonary bypass, allowing the surgeon to temporarily take over the function of the heart and lungs. Cardioplegic arrest is then initiated to stop the heart's activity, providing a still and bloodless field for the repair. The right atrium is opened through an incision (atriotomy) to expose the defect in the atrial septum. Depending on the size of the defect, it may be repaired directly with sutures if small, or a patch graft made from pericardial tissue or synthetic material may be used for larger defects. After the repair is completed, the right atrial incision is closed, and the patient is gradually weaned off cardiopulmonary bypass. Finally, chest tubes may be placed as necessary, and the chest incision is closed to complete the procedure.