CPT® Code 33478

1. Indications

The procedure described by CPT® Code 33478 is indicated for the treatment of infundibular pulmonary stenosis, which is characterized by the following conditions:

• Infundibular Pulmonary Stenosis - This condition involves an obstruction at the outflow tract of the right ventricle, which can significantly impede blood flow to the pulmonary artery.
• Obstructive Fibrous Muscle Band - The presence of a fibrous muscle band at the junction of the right ventricle and the infundibulum can lead to narrowing and obstruction, necessitating surgical intervention.
• Hypertrophied Infundibulum - Thickening of the muscular infundibulum can also contribute to the narrowing of the right ventricular outlet, requiring augmentation to restore normal blood flow.

2. Procedure

The procedure for outflow tract augmentation involves several critical steps, which are detailed as follows:

• Step 1: Accessing the Heart - The surgical procedure begins with a median sternotomy, which provides the necessary access to the thoracic cavity and the heart. This approach allows the surgeon to visualize and operate on the heart effectively.
• Step 2: Establishing Cardiopulmonary Bypass - Once access is achieved, cardiopulmonary bypass is established to maintain systemic circulation and oxygenation while the heart is being operated on. This is a crucial step that allows the surgeon to work on a still and bloodless field.
• Step 3: Incising the Pericardium - The pericardium, which is the fibrous sac surrounding the heart, is incised to expose the heart for the surgical procedure. A patch of pericardium may be harvested at this stage for use as a graft later in the procedure.
• Step 4: Incising the Right Ventricular Outflow Tract - The surgeon then incises the right ventricle along the outflow tract to access the area of obstruction. This incision is critical for addressing the underlying cause of the stenosis.
• Step 5: Addressing the Obstruction - If an obstructive fibrous muscle band is identified, it is excised to relieve the obstruction. Alternatively, if the obstruction is due to a hypertrophied infundibulum, the surgeon will remove tissue from the thickened area to enlarge the outflow tract.
• Step 6: Augmenting the Outflow Tract - The outflow tract is then enlarged using either an autologous pericardial patch graft or a synthetic patch, which serves to widen the passage and improve blood flow from the right ventricle.
• Step 7: Inspecting the Pulmonary Valve - The pulmonary valve is inspected for any abnormalities. If the commissures of the valve are found to be fused, the surgeon will perform a commissurotomy, which involves opening the three commissures using sharp dissection to restore normal function.
• Step 8: Closing the Heart - After all necessary interventions are completed, the heart is closed, and the patient is gradually weaned off cardiopulmonary bypass. This step is crucial for ensuring that the heart can resume its normal function.
• Step 9: Postoperative Management - Finally, chest tubes are placed as needed to manage any postoperative drainage, and the chest is closed to complete the procedure.

3. Post-Procedure

Post-procedure care following outflow tract augmentation typically involves monitoring the patient for any complications related to the surgery. Patients may require observation in a recovery unit where vital signs and cardiac function are closely monitored. The placement of chest tubes is common to facilitate drainage of any excess fluid or blood that may accumulate in the thoracic cavity. Recovery time can vary based on the individual patient's condition and the extent of the surgery performed. Follow-up appointments will be necessary to assess the success of the procedure and to monitor for any potential recurrence of stenosis or other complications. The healthcare team will provide specific instructions regarding activity restrictions, medication management, and signs of complications that should prompt immediate medical attention.