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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. Surgical techniques have evolved to include minimally invasive approaches that use epicardial radiofrequency ablation (RFA), a thoracoscopic or mediastinal approach and hybrid catheter ablations/open procedures.
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 and may also be used as first-line treatment. 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 pumping function. 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 criterion standard for surgical treatment of drug-resistant atrial fibrillation (AF) with an approximately 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 (RF) 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, transthoracic, 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 lesion 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” 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.
Several RFA systems that are used for cardiac tissue ablation have been cleared for marketing by FDA based on substantial equivalence to predicate devices. These include:
A number of cryoablation systems which may be used on cardiac ablation procedures have also been cleared for marketing, including:
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 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, are 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.
The use of an open maze or modified maze procedure performed on a non‒beating heart during cardiopulmonary bypass without concomitant cardiac surgery is considered not medically necessary for treatment of symptomatic, drug-resistant atrial fibrillation or flutter.
Given the availability of less-invasive alternative approaches in the treatment of atrial fibrillation (AF; see Catheter Ablation as Treatment for Atrial Fibrillation medical policy), performing the maze procedure without concomitant cardiac surgery should rarely be needed.
Published studies on the maze procedure describe patients with drug-resistant AF and atrial flutter as having experienced their arrhythmias for an average of 7 or more years and having unsuccessful results with an average of 5 or more antiarrhythmic medications.
Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Nervous/Mental Conditions, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:
A. consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and
B. appropriate with regard to standards of good medical practice; and
C. not solely for the convenience of the Member, his or her Provider; and
D. the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.
For the definition of Medically Necessary, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.
Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.
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.
08/27/2015: Code Reference section updated for ICD-10.
04/20/2016: Policy title updated to add "Atrial Flutter." Policy description updated regarding radiofrequency ablation and cryoablation systems. Policy statement updated to remove the phrase "without concomitant cardiac surgery" from the medically necessary statement for maze or modified maze during cardiopulmonary bypass. Added not medically necessary policy statement for open maze or modified maze done without concomitant cardiac surgery. Policy guidelines updated regarding the maze procedure without concomitant cardiac surgery and to add medically necessary and investigative definitions.
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.