Summary & Overview
CPT 33500: Closure of Cardiac Fistula on Cardiopulmonary Bypass
CPT code 33500 represents an open cardiac surgical procedure performed on cardiopulmonary bypass to close a fistula, either via an external approach or from within a cardiac chamber. As a component of complex cardiac surgical care, this code captures definitive repair of abnormal intracardiac or extracardiac communications that can cause hemodynamic instability, heart failure, or embolic risk. Nationally, accurate use of this code matters for clinical documentation, perioperative resource planning, and alignment of surgical quality metrics.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical context, typical site of service, and the types of information used in payer evaluations. The publication outlines common billing modifiers and related administrative considerations where available, and summarizes what is known about coding practice and reimbursement frameworks for major commercial payers and Medicare. It highlights the clinical scenarios that generate use of CPT code 33500, and provides a clear reference for clinicians, coding staff, and policy analysts seeking to understand how this procedure is classified and reported.
Billing Code Overview
CPT code 33500 describes a surgical procedure performed with the patient on cardiopulmonary bypass to close a fistula, either from outside the heart or from inside a cardiac chamber. The provider closes an abnormal passageway that permits blood to flow where it should not, eliminating the pathological communication between vascular or cardiac structures.
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Service type: Surgical cardiac procedure (open cardiac surgical repair)
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Typical site of service: Inpatient operating room with cardiopulmonary bypass (cardiac surgery suite)
Clinical & Coding Specifications
Clinical Context
A 58-year-old patient with a history of endocarditis presents with a continuous murmur and imaging-confirmed left-to-right intracardiac fistula between the left ventricle and right atrium. The patient is scheduled for surgical repair. Under general anesthesia and with the patient placed on cardiopulmonary bypass, the cardiothoracic surgeon identifies the fistulous tract and closes it directly from within the cardiac chamber. Intraoperative transesophageal echocardiography confirms adequate closure and no residual shunt prior to weaning from bypass. The typical workflow includes preoperative evaluation (history, physical, echocardiography, coronary angiography as indicated), intraoperative bypass and myocardial protection, direct or patch closure of the fistula, intraoperative imaging confirmation, and postoperative ICU monitoring for hemodynamic stability and arrhythmia surveillance.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier used / default | Applied when no specific modifier applies and standard reporting is intended |
22 | Increased procedural services | For unusually complex fistula repairs requiring substantially greater work than typical |