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Aetna Aetna
Clinical Policy Bulletin:
Maze Procedure
Number: 0225


Aetna considers the Maze procedure, performed with cardiopulmonary bypass on a beating heart, medically necessary for members with atrial fibrillation/flutter when any of the following criteria is met:

  • Member can not tolerate the side effects of drug therapy (adequate documentation of the nature and extent of the intolerance is required); or
  • Member is suffering the hemodynamic consequences of chronic atrial fibrillation/flutter despite adequate attempts at medical management; or
  • Member is at high-risk for thromboembolism as evidenced by either:

    • A previous episode of thromboembolism when other sources of emboli have been ruled out, or
    • Documented long-standing atrial fibrillation in members with mitral valve disease undergoing open surgical repair of the mitral valve.

Aetna considers the Maze procedure experimental and investigational for all other indications because its effectiveness for indications other than the ones listed above has not been established.

Aetna considers minimally invasive, off-pump Maze procedures, also known as thoracoscopic off-pump surgical ablation (TOPS), experimental and investigational for atrial fibrillation or flutter because there is insufficient evidence of their effectiveness.

See also CPB 0019 - Holter Monitors


The Maze procedure is a surgical treatment of atrial fibrillation (AF) in which multiple atrial incisions interrupt the pathogenic reentrant circuits and also direct the sinus impulses to the AV node along a specified route.  In addition, multiple blind "alleys" off the main conduction route allow for activation of the entire atrium.  By eliminating AF, this technique not only addresses the hemodynamic consequences of AF, it also eliminates the threat of thromboembolism AF can cause.

As part of the ongoing study of this procedure, individuals typically undergo a variety of post-operative tests to evaluate the status of the atria.  Unless clinically indicated by the member's signs and symptoms, these tests are considered not routinely medically necessary for post-operative evaluation.  Such tests include: endocardial catheter electrophysiology study; 24-hour Holter monitor; exercise stress test; and color-flow Doppler evaluation of transmitral and transtricuspid valve flow.

Gaynor and co-workers (2005) stated that the Cox maze procedure remains the gold standard for the treatment of AF and has excellent long-term efficacy.  The most significant predictor of late recurrence was duration of pre-operative AF, suggesting that earlier surgical intervention would further increase effectiveness.  This is in agreement with the findings of Chen et al (2005) who noted that the pre-operative left atrial size and duration of AF are primary predictors of sinus conversion by the radiofrequency Maze procedure for patients with persistent AF and mitral valve disease.  Moreover, in a systematic review on surgical treatment of AF, Khargi et al (2005) could not identify any significant difference in the post-operative sinus rhythm conversion rates between the classical "cut and sew" Cox-Maze III technique and the alternative sources of energy (e.g., radiofrequency-microwave and cryoblation), which were used to treat AF.

Thorascopic off-pump (TOP) surgical ablation (also known as mini Maze procedure, absent thoracotomy Maze procedure) is performed on a "beating heart" -- the heart is not arrested via bypass.  Use of a thorascope (a video telescope) helps surgeons guide the energy source to the atria.  Radiofrequency energy applied to the outside of the heart (epicardial ablation) is used for lesion creation.  This approach has many variants, but commonly involves pulmonary vein isolation at a minimum, as well as other potential ablation lines.  Bipolar radiofrequency energy is typically employed, in contrast to the unipolar energy employed in catheter ablation.

Krul et al (2013) presented a systematic literature overview and analysis of the first results and progress made with minimally-invasive surgery using radiofrequency energy in the treatment of AF.  The minimally-invasive treatment for AF tries to combine the success rate of surgical treatment with a less invasive approach to surgery.  It has the additional potential advantage of ganglion plexus (GP) ablation and left atrial appendage exclusion.  Furthermore, additional left atrial ablation lines (ALAL) can be created in non-paroxysmal AF patients.  For the search query ,multiple databases were used.  Exclusion and inclusion criteria were applied to select the publications to be screened.  All remaining articles were critically appraised and only relevant and valid articles were included in the results.  A total of 23 studies were included.  In 15 studies GPs around the pulmonary veins were ablated.  In 4 studies ALAL were performed.  Single procedure success rate was 69 % (95 % confidence interval [CI]: 58 % to 78 %) without anti-arrhythmic drugs (AAD) and 79 % (95 % CI: 71 % to 85 %) with AAD at 1 year follow-up.  Mortality was 0.4 %, and various complications were reported (3.2 % surgical, 3.2 % post-surgical, 2.6 % cardiac, 2.1 % pulmonary, and 1.7 % other).  The authors concluded that the 23 studies of minimally-invasive surgery for AF have been reviewed with success rates between that of the standard maze procedure and catheter ablation.  These first combined results show promise; however, minimally-invasive surgery is still evolving, for instance by the recent inclusion of electrophysiological endpoints.  Furthermore, the type of ALAL and the additional value of GP ablation have to be elucidated.

Sunderland et al (2011) examined if left atrial size reduction compared to maze surgery alone improve maze surgery success in adults undergoing a maze procedure for AF.  A total of 58 papers were found using the reported search, of which 8 represented the best evidence to answer the clinical question.  The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers were tabulated.  Four out of 8 papers compared a volume reduction technique as an adjunct to the maze procedure to a maze procedure alone -- all 4 papers reported that atrial volume reduction significantly increased restoration of sinus rhythm: 89.3 % versus 67.2 %, p < 0.001; 85 % versus 68 %, p < 0.05; 84 % versus  68 %, p < 0.05; 90 % versus 69 %, p < 0.05.  Three out of 8 papers had no control group but reported good rates of sinus rhythm restoration at last follow-up – 90 %, 92 % and 89 %, respectively -- despite the study population including atrial enlargement, a risk factor for failure of a maze procedure.  One paper reported no benefit of an atrial reduction plasty in patients with a left atrium (LA) greater than 70 mm.  An enlarged LA is a risk factor for failure of a maze procedure, and various models of AF suggested that reducing atrial mass and/or diameter may help to abolish the re-entry circuits underlying AF.  Furthermore, AF is uncommon when left atrial diameter is less than 40 mm, so there is at least some physiological basis for atrial reduction surgery in aiding the success of a maze procedure.  The evidence suggested that patients with an enlarged (greater than or equal to  55 mm) or giant (greater than or equal to 75 mm) LA who are at risk of failing to obtain sinus conversion after a standard maze procedure may derive benefit from concomitant atrial reduction surgery using either a tissue excision or a tissue plication technique.  However, the authors concluded that the evidence is not strong since the papers available are not readily comparable owing to substantial variations in the populations and procedures involved.  They therefore, emphasized the need for prospective, randomized studies in this area.

Bum Kim et al (2012) noted that the long-term benefits of the maze procedure in patients with chronic AF undergoing mechanical valve replacement who already require lifelong anti-coagulation remain unclear.  These investigators evaluated adverse outcomes (death; thromboembolic events; composite of death, heart failure, or valve-related complications) in 569 patients with AF-associated valvular heart disease who underwent mechanical valve replacement with (n = 317) or without (n = 252) a concomitant maze procedure between 1999 and 2010.  After adjustment for differences in baseline risk profiles, patients who had undergone the maze procedure were at similar risks of death (hazard ratio, 1.15; 95 % CI: 0.65 to 2.03; p = 0.63) and the composite outcomes (hazard ratio, 0.82; 95 % CI: 0.50 to 1.34; p = 0.42) but a significantly lower risk of thromboembolic events (hazard ratio, 0.29; 95 % CI: 0.12 to 0.73; p = 0.008) compared with those who underwent valve replacement alone at a median follow-up of 63.6 months (range of 0.2 to 149.9 months).  The effect of superior event-free survival by the concomitant maze procedure was notable in a low-risk EuroSCORE (0 to 3) subgroup (p = 0.049), but it was insignificant in a high-risk EuroSCORE (greater than or equal to 4) subgroup (p = 0.65).  Furthermore, the combination of the maze procedure resulted in superior left ventricular (p < 0.001) and tricuspid valvular functions (p < 0.001) compared with valve replacement alone on echocardiographic assessments performed at a median of 52.7 months (range of 6.0 to 146.8 months) after surgery.  The authors concluded that compared with valve replacement alone, the addition of the maze procedure was associated with a reduction in thromboembolic complications and improvements in hemodynamic performance in patients undergoing mechanical valve replacement, particularly in those with low-risk of surgery.

With thorascopic “off-pump” (TOP) surgical ablation, the heart is not arrested via bypass, and minimally-invasive techniques are used. Radiofrequency energy applied to the outside of the heart (epicardial ablation) is used for lesion creation. This approach has many variants, but typically involves pulmonary vein isolation at a minimum, as well as other potential ablation lines. An assessment by the Institute for Clinical and Economic Review (2010) found that the evidence for TOP surgical ablation was particularly scant; the ICER review identified no randomized controlled trials, and the remaining case series and cohort studies varied significantly in technical approach, outcome measurement, and level of reporting detail. The ICER review stated: "Thorascopic, off-pump surgical ablation is an emerging surgical technique, as there are many variations in how the procedure is performed, there is no evidence on longer term outcomes, and what evidence is available on intermediate or surrogate outcomes is limited to a few surgical case series."

La Meir et al (2013) stated that despite its proven effectiveness, the Cox-Maze III procedure did not gain widespread acceptance for the treatment of stand-alone AF (SA-AF) because of its complexity and technical difficulty.  Surgical ablation for SA-AF can now be successfully performed utilizing minimally invasive surgery (MIS).  These investigators provided an overview of state-of-the-art MIS for the treatment of SA-AF.  Studies selected for this review were identified on PubMed and exclusion and inclusion criteria were applied to select the publication to be screened.  A total of 28 studies were included; 27 (96.4 %) were observational in nature whereas 1 was prospective non-randomized.  The total number of patients was 1,051 (range of 14 to 114).  Mean age ranged from 45.3 to 67.1 years.  Suboptimal results were obtained when employing microwave and high focused ultrasound energies.  In contrast, MIS ablation of SA-AF achieved satisfactory 1-year results when the bipolar radiofrequency was employed as energy source, with anti-arrhythmic drug-free success rate comparable to percutaneous catheter ablation (PCA).  The success rate in paroxysmal was even higher than in PCA.  In contrast, ganglionated plexi ablation and left atrial appendage removal seem not to influence the recurrence of AF and the occurrence of post-operative thrombo-embolic events.  The authors concluded that minimally invasive surgery ablation of SA-AF achieved satisfactory 1-year results when the bipolar radiofrequency was employed.  Nevertheless, the relatively high complication rate reported suggested that such techniques require further refinement.  Finally, the authors noted that preliminary results of the hybrid approach are promising but they need to be confirmed.

CPT Codes / HCPCS Codes / ICD-9 Codes
CPT codes covered if selection criteria are met:
33254 Operative tissue ablation and reconstruction of atria, limited (e.g., modified maze procedure)
33256 Operative tissue ablation and reconstruction of atria, extensive (eg, maze procedure); with cardiopulmonary bypass
+ 33257 Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s), limited (e.g., modified maze procedure) (List separately in addition to code for primary procedure)
+ 33259 Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s), extensive (e.g., maze procedure), with cardiopulmonary bypass (List separately in addition to code for primary procedure)
CPT codes not covered for indications listed in the CPB:
33255 Operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure); without cardiopulmonary bypass
+33258 Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s), extensive (e.g., maze procedure), without cardiopulmonary bypass (List separately in addition to code for primary procedure)
33265 Endoscopy, surgical; operative tissue ablation and reconstruction of atria, limited (e.g., modified maze procedure), without cardiopulmonary bypass
33266     operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure), without cardiopulmonary bypass
Other CPT codes related to the CPB:
62302 - 62305 Myelography via lumbar injection, including radiological supervision and interpretation
93015 Cardiovascular stress test using maximal or submaximal treadmill or bicycle exercise, continuous electrocardiographic monitoring, and/or pharmacological stress; with physician supervision, with interpretation and report
93224 - 93237 Electrocardiographic monitoring for 24 hours
93600 - 93660 Intracardiac electrophysiological procedures/studies
ICD-9 codes covered if selection criteria are met:
427.31 Atrial fibrillation [chronic]
427.32 Atrial flutter [chronic]
Other ICD-9 codes related to the CPB:
424.0 Mitral valve disorders
444.0 - 445.89 Arterial embolism and thrombosis or atheroembolism
V12.51 Personal history of venous thrombosis and embolism

The above policy is based on the following references:
  1. Sundt TM 3rd, Camillo CJ, Cox JL. The maze procedure for cure of atrial fibrillation. Cardiol Clin. 1997;15(4):739-748.
  2. Izumoto H, Kawazoe K, Kitahara H, et al. Can the maze procedure be combined safely with mitral valve repair? J Heart Valve Dis. 1997;6(2):166-170.
  3. Cox JL, Sundt TM 3rd. The surgical management of atrial fibrillation. Annu Rev Med. 1997;48:511-523.
  4. Cox JL, Schuessler RB, Lappas DG, et al. An 8 1/2-year clinical experience with surgery for atrial fibrillation. Ann Surg. 1996;224(3):267-273.
  5. Luderitz B, Pfeiffer D, Tebbenjohanns J, et al. Nonpharmacologic strategies for treating atrial fibrillation. Am J Cardiol. 1996;77(3):45A-52A.
  6. McCarthy PM, Castle LW, Maloney JD. Initial experience with the Maze procedure for atrial fibrillation. J Thorac Cardiovasc Surg. 1993;105:1077-1087.
  7. Cannom DS. Atrial fibrillation: Nonpharmacologic approaches. Am J Cardiol. 2000;85(10 Suppl 1):25-35.
  8. Cox JL, Ad N. New surgical and catheter-based modifications of the Maze procedure. Semin Thorac Cardiovasc Surg. 2000;12(1):68-73.
  9. Cox JL, Ad N, Palazzo T, et al. Current status of the Maze procedure for the treatment of atrial fibrillation. Semin Thorac Cardiovasc Surg. 2000;12(1):15-19.
  10. Yuda S, Nakatani S, Kosakai Y, et al. Long-term follow-up of atrial contraction after the maze procedure in patients with mitral valve disease. J Am Coll Cardiol. 2001;37(6):1622-1627.
  11. Deneke T, Khargi K, Grewe PH, et al. Left atrial versus bi-atrial Maze operation using intraoperatively cooled-tip radiofrequency ablation in patients undergoing open-heart surgery: Safety and efficacy. J Am Coll Cardiol. 2002;39(10):1644-1650.
  12. Green B. The maze III surgical procedure. AORN J. 2002;76(1):134-146; quiz 147-150.
  13. Gillinov AM, Blackstone EH, McCarthy PM. Atrial fibrillation: Current surgical options and their assessment. Ann Thorac Surg. 2002;74(6):2210-2217.
  14. Institute for Clinical Systems Improvement (ICSI). Atrial fibrillation. ICSI Health Care Guideline. Bloomington, MN: ICSI; November 2002. Available at: Accessed June 17, 2003.
  15. American College of Cardiology, American Heart Association, European Society of Cardiology, Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation. ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences. J Am Coll Cardiol. 2001;38:1266i-lxx. Available at: Accessed June 17, 2003.
  16. Swedish Council on Technology Assessment in Health Care (SBU). The maze procedure in treating atrial fibrillation - early assessment briefs (ALERT). Stockholm, Sweden: SBU; 2002.
  17. Gillinov AM, McCarthy PM, Marrouche N, Natale A. Contemporary surgical treatment for atrial fibrillation. Pacing Clin Electrophysiol. 2003;26(7 Pt 2):1641-1644.
  18. Miller JM, Olgin JE, Das MK. Atrial fibrillation: What are the targets for intervention? J Interv Card Electrophysiol. 2003;9(2):249-257.
  19. Hirata M, Bando K, Kobayashi J, et al. Effect of maze procedure in patients with atrial fibrillation undergoing valve replacement. J Heart Valve Dis. 2002;11(5):719-725.
  20. Jessurun ER, van Hemel NM, Defauw JJ, et al. A randomized study of combining maze surgery for atrial fibrillation with mitral valve surgery. J Cardiovasc Surg. 2003;44(1):9-18.
  21. Misaki T, Fukahara K. Recent topics on the surgical treatment for atrial fibrillation. Ann Thorac Cardiovasc Surg. 2004;10(5):277-280.
  22. de Lima GG, Kalil RA, Leiria TL, et al. Randomized study of surgery for patients with permanent atrial fibrillation as a result of mitral valve disease. Ann Thoracic Surg. 2004;77(6):2089-2095.
  23. Gaynor SL, Schuessler RB, Bailey MS, et al. Surgical treatment of atrial fibrillation: Predictors of late recurrence. J Thorac Cardiovasc Surg. 2005;129(1):104-111.
  24. Khargi K, Hutten BA, Lemke B, Deneke T. Surgical treatment of atrial fibrillation: A systematic review. Eur J Cardiothorac Surg. 2005;27(2):258-265.
  25. Chen MC, Chang JP, Chang HW, et al. Clinical determinants of sinus conversion by radiofrequency maze procedure for persistent atrial fibrillation in patients undergoing concomitant mitral valvular surgery. Am J Cardiol. 2005;96(11):1553-1557. 
  26. Reston JT, Shuhaiber JH. Meta-analysis of clinical outcomes of maze-related surgical procedures for medically refractory atrial fibrillation. J Cardiothorac Surg. 2005;28(5):724-730.
  27. Barnett SD, Ad N. Surgical ablation as treatment for the elimination of atrial fibrillation: A meta-analysis. J Thorac Cardiovasc Surg. 2006;131(5):1029-1035.
  28. Wong JW, Mak KH. Impact of maze and concomitant mitral valve surgery on clinical outcomes. Ann Thorac Surg. 2006;82(5):1938-1947.
  29. Bakir I, Casselman FP, Brugada P, et al. Current strategies in the surgical treatment of atrial fibrillation: Review of the literature and Onze Lieve Vrouw Clinic's strategy. Ann Thorac Surg. 2007;83(1):331-340.
  30. Lall SC, Melby SJ, Voeller RK, et al. The effect of ablation technology on surgical outcomes after the Cox-maze procedure: A propensity analysis. J Thorac Cardiovasc Surg. 2007;133(2):389-396. 
  31. Stulak JM, Sundt TM 3rd, Dearani JA, et al. Ten-year experience with the Cox-maze procedure for atrial fibrillation: How do we define success? Ann Thorac Surg. 2007;83(4):1319-1324.
  32. Khargi K, Keyhan-Falsafi A, Hutten BA, et al. Surgical treatment of atrial fibrillation : A systematic review. Herzschrittmacherther Elektrophysiol. 2007;18(2):68-76.
  33. Backer CL, Tsao S, Deal BJ, Mavroudis C. Maze procedure in single ventricle patients. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu. 2008:44-48.
  34. Srivastava V, Kumar S, Javali S, et al. Efficacy of three different ablative procedures to treat atrial fibrillation in patients with valvular heart disease: A randomised trial. Heart Lung Circ. 2008;17(3):232-240.
  35. Quenneville SP, Xie X, Brophy JM. The cost-effectiveness of Maze procedures using ablation techniques at the time of mitral valve surgery. Int J Technol Assess Health Care. 2009;25(4):485-496.
  36. Damiano RJ Jr, Schwartz FH, Bailey MS, et al. The Cox maze IV procedure: Predictors of late recurrence. J Thorac Cardiovasc Surg. 2011;141(1):113-121.
  37. Krul SP, Driessen AH, Zwinderman AH, et al. Navigating the mini-maze: Systematic review of the first results and progress of minimally-invasive surgery in the treatment of atrial fibrillation. Int J Cardiol. 2013;166(1):132-140.
  38. Gersh BJ, Maron BJ, Bonow RO, et al. 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy: A report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol 2011;58(25):e212-e260.
  39. Sunderland N, Nagendran M, Maruthappu M. In patients with an enlarged left atrium does left atrial size reduction improve maze surgery success? Interact Cardiovasc Thorac Surg. 2011;13(6):635-641.
  40. Bum Kim J, Suk Moon J, Yun SC, et al. Long-term outcomes of mechanical valve replacement in patients with atrial fibrillation: Impact of the maze procedure. Circulation. 2012;125(17):2071-2080.
  41. La Meir M, Gelsomino S, Luca F, et al. Minimal invasive surgery for atrial fibrillation: An updated review. Europace. 2013;15(2):170-182.

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Copyright Aetna Inc. All rights reserved. Clinical Policy Bulletins are developed by Aetna to assist in administering plan benefits and constitute neither offers of coverage nor medical advice. This Clinical Policy Bulletin contains only a partial, general description of plan or program benefits and does not constitute a contract. Aetna does not provide health care services and, therefore, cannot guarantee any results or outcomes. Participating providers are independent contractors in private practice and are neither employees nor agents of Aetna or its affiliates. Treating providers are solely responsible for medical advice and treatment of members. This Clinical Policy Bulletin may be updated and therefore is subject to change.
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