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There are a variety of surgical approaches to treat atrial fibrillation (AF) that work by interrupting abnormal electrical activity in the atria. Open surgical procedures, such as the Cox-Maze procedure were first developed for this purpose and are now generally performed in conjunction with valvular or coronary artery bypass graft (CABG) surgery. Minimally invasive surgical techniques employ epicardial radiofrequency ablation (RFA) and are done via the thoracoscopic or mediastinal approach.
Atrial fibrillation (AF) is a supraventricular tachyarrhythmia, characterized by disorganized atrial activation with ineffective atrial ejection. The underlying mechanism of AF involves interplay between electrical triggering events that initiate AF 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 first-line treatment for AF usually includes medications to maintain sinus rhythm and/or control the ventricular rate. Antiarrhythmic medications are only partially effective; therefore, medical treatment is not sufficient for many patients. Percutaneous catheter ablation, using endocardial ablation, is an accepted second-line treatment for patients who are not adequately controlled on medications. Catheter ablation is successful in maintaining sinus rhythm for most patients, but long-term recurrences are common and increase over time. Surgical ablation, performed either by open surgical techniques or thoracoscopy, is an alternative approach to percutaneous catheter ablation.
Open surgical techniques. The classic Cox maze III procedure is a complex surgical procedure that involves sequential atriotomy incisions that interrupt 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:
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.
Minimally invasive (thoracoscopic) techniques. In addition, less invasive, trans-thoracic, endoscopic, off-pump procedures to treat drug-resistant AF have been developed. 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.
Hybrid techniques. “Hybrid” ablation refers to a procedure that uses both thoracoscopic and percutaneous approaches in the same patient. Ablation is performed on the outer surface of the heart (epicardial) via the thoracoscopic approach, and on the inner surface of the heart (endocardial) via the percutaneous approach. The rationale for doing a hybrid procedure is that a combination of both techniques may result in more complete ablation. Thoracoscopic epicardial ablation is limited by the inability to perform all possible ablation lines, because the posterior portions of the heart are not accessible via thoracoscopy. Percutaneous, endoscopic ablation is limited by incomplete ablation lines that often require repeat procedures. By combining both procedures, a full set of ablation lines can be performed, and incomplete ablation lines can be minimized.
The hybrid approach first involves thoracoscopy with epicardial ablation. Following this procedure, an electrophysiologic study is performed percutaneously followed by endocardial ablation as directed by the results of electrophysiology. Most commonly, the electrophysiology study and endocardial ablation are done immediately after the thoracoscopy as part of a single procedure. However, some hybrid approaches perform the electrophysiology study and endocardial ablation, as directed by the electrophysiology study, on a separate day.
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.
POLICYThe maze or modified maze procedure, performed on a non-beating heart during cardiopulmonary bypass with or without concomitant cardiac surgery is considered medically necessary for treatment of symptomatic, drug-resistant atrial fibrillation or flutter.
Minimally invasive, off-pump maze procedures (ie, modified maze procedures), including those done via mini-thoracotomy, is considered investigational for treatment of atrial fibrillation or flutter.
Hybrid ablation (defined as a combined percutaneous and thoracoscopic approach) is considered investigational for the treatment of atrial fibrillation or flutter.
POLICY GUIDELINESInvestigative service is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized by certifying boards and/or approving or licensing agencies or published peer review criteria as standard, effective medical practice for the treatment of the condition being treated and as such therefore is not considered medically necessary.
The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.
POLICY HISTORY12/13/2006: Policy added.
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.
10/24/2013: Added the following policy statement: Hybrid ablation (defined as a combined percutaneous and thoracoscopic approach) is considered investigational for the treatment of atrial fibrillation or flutter. Added ICD-9 procedure code 37.37 to the Code Reference section.
09/11/2014: Policy reviewed; description updated regarding hybrid techniques. Medically necessary policy statement updated to state that the maze or modified maze procedure, performed on a non-beating heart during cardiopulmonary bypass with or without concomitant cardiac surgery is considered medically necessary for treatment of symptomatic, drug-resistant atrial fibrillation or flutter. First investigational policy statement revised to add "(ie, modified maze procedures)" and remove "pulmonary vein isolation" and "drug-resistant" from the statement. It previously stated: 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. Removed deleted CPT code 33253 from the Code Reference section.
04/20/2015: CPT code 33257 moved from investigational to covered in the Code Reference section.
SOURCE(S)Blue Cross Blue Shield Association Policy # 7.01.14
CODE REFERENCEThis may not be a comprehensive list of procedure codes applicable to this policy.
The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document.