Summary & Overview
CPT 33427: Mitral Valvuloplasty with Cardiopulmonary Bypass
CPT code 33427 represents mitral valvuloplasty performed with cardiopulmonary bypass — a complex open-heart surgical repair of the mitral valve and subvalvular apparatus. Nationally, this code captures procedures intended to correct mitral stenosis, subvalvular fibrosis, and annular dilatation-related insufficiency, including intraoperative ring or band placement when indicated. The procedure is clinically significant due to its role in preserving native valve function, reducing the need for prosthetic replacement, and affecting perioperative resource use and outcomes.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context, typical site of service, and the service type associated with the code. The publication also outlines commonly applied modifiers and governance-relevant considerations for coding and billing workflows. Policy and benchmarking content highlights how this code is treated across major national payers and in Medicare coverage frameworks, offering readers a clear picture of reimbursement posture, utilization considerations, and documentation expectations tied to mitral valve repair with cardiopulmonary bypass.
This executive summary is intended for clinical coders, revenue cycle professionals, and policy analysts looking for a national-level briefing on coding, billing, and clinical implications for CPT code 33427.
Billing Code Overview
CPT code 33427 describes a mitral valvuloplasty with cardiopulmonary bypass, a surgical repair of the mitral valve or subvalvular structures performed while the patient is supported on a heart–lung machine. The procedure corrects mitral stenosis or subvalvular fibrosis and may include placement of a band or ring around the annulus to address mitral insufficiency from annular dilatation.
Service type: Invasive cardiac surgical procedure (valve repair) performed with cardiopulmonary bypass
Typical site of service: Inpatient operating room or cardiac surgery suite with postoperative inpatient recovery
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient with progressive exertional dyspnea, orthopnea, and a history of rheumatic heart disease presents with echocardiographic evidence of severe mitral stenosis with commissural fusion and subvalvular thickening. The cardiothoracic surgical team evaluates the patient for operative management after multidisciplinary review. The clinical workflow includes preoperative testing (transthoracic and transesophageal echocardiography, cardiac catheterization if indicated to assess coronaries, labs, and crossmatch), informed consent, intraoperative transesophageal echocardiography, and cardiopulmonary bypass. Intraoperatively the surgeon performs a surgical mitral valvuloplasty/repair (33427) with debridement of fused commissures and repair of subvalvular apparatus; an annuloplasty ring may be placed if annular dilatation or regurgitation is present. Postoperative care includes intensive care unit monitoring, hemodynamic assessment, anticoagulation management if indicated, follow-up echocardiography prior to discharge, and outpatient cardiology and cardiothoracic follow-up.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Full code (no modifier) | Default reporting when no modifier applies for the primary procedure. |