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Official Description

Shunt; ascending aorta to pulmonary artery (Waterston type operation)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The procedure described by CPT® Code 33755 involves the surgical creation of a shunt that connects the ascending aorta to the pulmonary artery, commonly known as the Waterston type operation. This operation is performed to facilitate blood flow from the aorta directly into the pulmonary artery, which can help alleviate symptoms of cyanosis that arise from certain congenital heart defects, particularly in patients with conditions such as tetralogy of Fallot. The Waterston operation is one of two types of shunts historically used for this purpose; the other being the Potts or Potts-Smith operation, which connects the descending aorta to the pulmonary artery (CPT® Code 33762). Both procedures have seen a decline in use due to the potential complications that can arise from them. The surgical approach typically involves exposing the heart and surrounding blood vessels through a median sternotomy or thoracotomy, allowing the surgeon to access the ascending aorta and the right pulmonary artery. During the procedure, these two vessels are incised and connected in a side-to-side manner, creating a new pathway for blood flow. This intervention is intended as a temporary measure to manage the symptoms associated with significant cardiac anomalies until more definitive surgical corrections can be performed.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The Waterston type operation (CPT® Code 33755) is indicated for patients experiencing significant cyanosis due to congenital heart defects, particularly those associated with conditions such as:

  • Tetralogy of Fallot A complex congenital heart defect characterized by four specific heart abnormalities that result in insufficient oxygenation of blood.
  • Other Cardiac Anomalies Various congenital heart defects that lead to inadequate blood flow to the lungs, resulting in cyanosis.

2. Procedure

The procedure for CPT® Code 33755 involves several critical steps to successfully create the shunt between the ascending aorta and the pulmonary artery. The following outlines the procedural steps:

  • Step 1: Anesthesia and Positioning The patient is placed under general anesthesia, and appropriate positioning is ensured to provide optimal access to the thoracic cavity.
  • Step 2: Surgical Access A median sternotomy or thoracotomy is performed to expose the heart and major blood vessels. This involves making an incision along the sternum or side of the chest to gain access to the thoracic cavity.
  • Step 3: Identification of Vessels The ascending aorta and the right pulmonary artery are carefully identified and dissected to prepare for the shunt creation.
  • Step 4: Incision and Connection The ascending aorta and the right pulmonary artery are incised. The surgeon then connects these two vessels in a side-to-side fashion, allowing blood to flow from the aorta directly into the pulmonary artery.
  • Step 5: Closure After ensuring that the shunt is functioning correctly, the surgical site is closed in layers, and the patient is monitored for any immediate postoperative complications.

3. Post-Procedure

Post-procedure care following the Waterston type operation includes close monitoring of the patient for any signs of complications, such as bleeding or infection. Patients may require intensive care for a period following the surgery to ensure stable hemodynamics and adequate oxygenation. Follow-up evaluations are essential to assess the effectiveness of the shunt and to determine if further surgical interventions are necessary. The expected recovery time can vary based on the patient's overall health and the complexity of the procedure, but careful management and observation are critical during the initial recovery phase.

Short Descr SHUNT AS-AORT TO PULM ART
Medium Descr SHUNT ASCENDING AORTA TO PULMONARY ARTERY
Long Descr Shunt; ascending aorta to pulmonary artery (Waterston type operation)
Status Code Active Code
Global Days 090 - Major Surgery
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 2 - Payment restriction for assistants at surgery does not apply to this procedure...
Co-Surgeons (62) 1 - Co-surgeons could be paid, though supporting documentation is required...
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Inpatient Procedures, not paid under OPPS
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P2F - Major procedure, cardiovascular-Other
MUE 1
CCS Clinical Classification 56 - Other vascular bypass and shunt, not heart

This is a primary code that can be used with these additional add-on codes.

33257 Addon Code MPFS Status: Active Code APC C Illustration for Code Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s), limited (eg, modified maze procedure) (List separately in addition to code for primary procedure)
33258 Addon Code MPFS Status: Active Code APC C Illustration for Code Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s), extensive (eg, maze procedure), without cardiopulmonary bypass (List separately in addition to code for primary procedure)
33924 Addon Code MPFS Status: Active Code APC C CPT Assistant Article Ligation and takedown of a systemic-to-pulmonary artery shunt, performed in conjunction with a congenital heart procedure (List separately in addition to code for primary procedure)
34714 Addon Code MPFS Status: Active Code APC N ASC N1 Open femoral artery exposure with creation of conduit for delivery of endovascular prosthesis or for establishment of cardiopulmonary bypass, by groin incision, unilateral (List separately in addition to code for primary procedure)
34716 Addon Code MPFS Status: Active Code APC N ASC N1 Open axillary/subclavian artery exposure with creation of conduit for delivery of endovascular prosthesis or for establishment of cardiopulmonary bypass, by infraclavicular or supraclavicular incision, unilateral (List separately in addition to code for primary procedure)
34833 Addon Code Resequenced Code MPFS Status: Active Code APC C CPT Assistant Article Open iliac artery exposure with creation of conduit for delivery of endovascular prosthesis or for establishment of cardiopulmonary bypass, by abdominal or retroperitoneal incision, unilateral (List separately in addition to code for primary procedure)
Date
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2025-01-01 Changed Short and Medium Descriptions changed.
Pre-1990 Added Code added.
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