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The classic Cox maze III procedure is a complex surgical procedure that involves sequential atriotomy incisions that interrupt potential re-entrant circuits which interrupts the aberrant atrial conduction pathways in the heart for patients with atrial fibrillation. The procedure is also intended to preserve atrial function (pumping). It is indicated for patients who do not respond to medical or other surgical antiarrhythmic therapies and is often performed in conjunction with correction of structural cardiac conditions such as valve repair or replacement. This procedure is considered the gold-standard for surgical treatment of drug-resistant atrial fibrillation (AF) with about a 90% success rate.       

The maze procedure entails making incisions in the heart that:

• direct an impulse from the sinoatrial (SA) node to the atrioventricular (AV) node;
• preserve activation of the entire atrium; and
• block re-entrant impulses that are responsible for atrial fibrillation (AF) or atrial flutter (AFl ). 

The classic Cox maze procedure is performed on a non-beating heart during cardiopulmonary bypass. Simplification of the maze procedure has evolved with the use of different ablation tools such as microwave, cryotherapy, ultrasound, and radiofrequency energy sources to create the atrial lesions instead of employing the incisional technique used in the classic maze procedure.   

In addition, less invasive, trans-thoracic, endoscopic, off-pump procedures to treat drug-resistant AF are being developed and evaluated. The evolution of these procedures involves both different surgical approaches and different lesion sets. Alternative surgical approaches include mini-thoracotomy, and total thoracoscopy with video assistance. Open thoracotomy and mini-thoracotomy employ cardiopulmonary bypass and open heart surgery, while thoracoscopic approaches are performed on the beating heart. Thoracoscopic approaches do not enter the heart and use epicardial ablation lesion sets, whereas the open approaches use either the classic “cut and sew” approach or endocardial ablation. Lesion sets may vary independent of the surgical approach, with a tendency towards less extensive lesion sets targeted to areas that are most likely to be triggers of AF. The most limited lesion sets involve pulmonary vein isolation and exclusion of the left atrial appendage. More extensive lesions sets include linear ablations of the left and/or right atrium, and ablation of ganglionic plexi. Some surgeons perform left-atrial reduction in cases of left-atrial enlargement. The type of energy used for ablation also varies; radiofrequency energy is most commonly applied. Other types of energy sources such as cryoablation and high-intensity ultrasound have also been used. For the purposes of this policy statement, the variations on surgical procedures for AF will be combined under the heading of ‘modified Maze’ procedures.   

Atrial fibrillation is a supraventricular tachyarrhythmia, characterized by disorganized atrial activation with ineffective atrial ejection. The underlying mechanism of AF involves interplay between electrical triggering events and the myocardial substrate that permits propagation and maintenance of the aberrant electrical circuit. The most common focal trigger of AF appears to be located within the cardiac muscle that extends into the pulmonary veins. The atria are frequently abnormal in patients with AF and demonstrate enlargement or increased conduction time. Atrial flutter is a variant of atrial fibrillation. The FDA approved (January 2002) the Medtronic Cardioblate System which uses radiofrequency (RF) energy to ablate cardiac tissue.  The Cardima SAS (Surgical Ablation System) used during mini-thoracotomy received 510(k) approval by the FDA in 2003 as substantially equivalent to the Medtronic device for performing ablation of cardiac tissue with RF energy. Another bipolar RF device approved for use in surgical procedures is manufactured by Aticure, Inc.    

Note: This policy does not address percutaneous catheter ablation procedures for treatment of atrial fibrillation. Also, pulmonary vein isolation and ablation as a treatment of atrial fibrillation is covered separately.

See Pulmonary Vein Isolation and Ablation as a Treatment of Atrial Fibrillation policy.

Minimally invasive, off-pump maze procedures, including pulmonary vein isolation via mini-thoracotomy, is considered investigational for treatment of drug-resistant atrial fibrillation or flutter.

None

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

1/2/2007: Code reference section updated per the 2007 CPT/HCPCS revisions

3/22/2007: Reviewed and approved by the Medical Policy Advisory Committee (MPAC)

12/18/07: Coding updated per 2008 CPT/HCPCS revisions

5/9/2008: Policy reviewed, no changes

9/22/2008: Annual ICD-9 updates effective 10-1-2008 applied

10/14/2010: Annual ICD-9 code update: Revised the description of ICD-9 procedure code 37.34.

02/23/2011:  Policy title changed from "Maze Procedure" to "Open and Thoracoscopic Approaches to Treat Atrial Fibrillation (Maze and Related Procedures)."  Policy description updated; policy statement unchanged.

07/12/2012: Policy reviewed; no changes.

The code(s) listed below are ONLY covered if the procedure is performed according to the "Policy" section of this document. 

Covered Codes

This is not an all-inclusive list of non-covered procedure codes.

The code(s) listed below and ANY code not listed in the previous section are considered non-covered for this procedure. 

Non-Covered Codes