CPT® Code 33735

The procedure described by CPT® Code 33735 involves an atrial septectomy or septostomy performed using a closed heart technique, specifically known as the Blalock-Hanlon type operation. This surgical intervention is primarily aimed at improving oxygen saturation in patients who present with transposition anomalies of the great vessels, a condition where the major arteries are incorrectly positioned. The procedure is conducted through a right lateral thoracotomy, which is an incision made on the side of the chest to access the heart without the need for cardiopulmonary bypass. During the operation, the physician places clamps on a small segment of both the right and left atria to temporarily occlude blood flow. This allows for the creation of two parallel incisions—one in the right atrium and one in the left atrium—near the septum. The intra-atrial septum is then manipulated, with the posterior aspect being excised to facilitate improved blood flow and oxygenation. After the necessary modifications to the septum are made, the clamps are repositioned, allowing the septum to fall back into the atrial cavity, and the incisions in the atria are subsequently closed. This closed heart approach is contrasted with the open heart technique described in CPT® Code 33736, which involves the use of cardiopulmonary bypass and is typically reserved for cases where the atrial septum is particularly thick.