CurrentPremera BluecrossPolicy N/A

Cox maze and surgical/hybrid ablation procedures for atrial fibrillation

Defines medical necessity, investigational status, and documentation/coding guidance for maze (Cox maze), modified maze, minimally invasive thoracoscopic, and hybrid ablation procedures used to treat atrial fibrillation or atrial flutter for Premera Bluecross.

Policy Summary

PayerPremera Bluecross

PolicyCox maze and surgical/hybrid ablation procedures for atrial fibrillation

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateSep 1, 2023

Next Review DateN/A

Key ActionDocument medical necessity and include office visit notes describing the requested maze/modified maze and the concomitant cardiac surgery.

SourceLink

POLICY UPDATE CHANGES

No material clinical or coverage changes in this revision.

33254-33266CPT codes listed for maze and related procedures

Several RCTsEvidence for concomitant maze with cardiac surgery

5 RCTsRandomized trials evaluating hybrid procedures cited

2023-2024Guideline citations (recent)

87+References listed

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Coverage Criteria for Maze and Related Procedures

Coverage determinations provided by procedure type:

Medically necessary: Maze or modified maze procedure performed on a non-beating heart during cardiopulmonary bypass with concomitant cardiac surgery (CPT 33257, 33259) is considered medically necessary for the treatment of symptomatic atrial fibrillation or atrial flutter.

Documentation: medical records must document indication, relevant history/physical, and the concomitant cardiac surgery being performed.

Not medically necessary: Open maze or modified maze procedure performed on a non-beating heart during cardiopulmonary bypass without concomitant cardiac surgery (CPT 33254, 33256) is considered not medically necessary for the treatment of atrial fibrillation or atrial flutter.

Given availability of less-invasive alternatives, performing the maze procedure without concomitant cardiac surgery should rarely be needed.

Investigational / Not covered: Stand‑alone minimally invasive off‑pump maze procedures (including mini‑thoracotomy approaches) (CPT 33254, 33255) and hybrid ablation (combined percutaneous endocardial and thoracoscopic epicardial approaches; CPTs 33254, 33258, 33265, 33266) are considered investigational for the treatment of atrial fibrillation or atrial flutter.

All other variations of the procedure outside of maze performed during cardiopulmonary bypass with concomitant cardiac surgery are considered investigational/not covered.

Guideline-based indications (summarized)

Guideline-derived coverage considerations and clinical scenarios described in cited society guidance:

Guideline-based indications (summarized): Concomitant surgical ablation is recommended or advised for patients with paroxysmal or persistent atrial fibrillation undergoing open left‑atrial or other cardiac surgery to restore sinus rhythm and improve outcomes; concomitant ablation is beneficial regardless of prior antiarrhythmic drug failure or intolerance.

Sources: STS, AHA/ACC/HRS, HRS consortia, AATS.

Biatrial Cox‑Maze III/IV lesion set or at minimum pulmonary vein isolation plus left atrial posterior wall isolation is endorsed as beneficial when performed concomitantly with left atrial open cardiac surgery.

STS and HRS publications provide class/level recommendations supporting concomitant procedures.

Stand‑alone surgical or hybrid ablation may be reasonable for symptomatic patients with persistent AF who have had prior unsuccessful catheter ablation or who are intolerant/refractory to antiarrhythmic drug therapy; consideration of relative safety and efficacy and patient preference is required.

Guideline class: may be reasonable/IIa–IIb depending on society and clinical scenario.

Medically necessary when performed with concomitant cardiac surgery

Maze or modified maze performed during cardiopulmonary bypass with concomitant cardiac surgery (CPT 33257, 33259) — MEDICALLY NECESSARY.

Documentation should confirm symptomatic AF/atrial flutter and the planned concomitant cardiac procedure.

Not medically necessary / Investigational when performed without concomitant cardiac surgery

Open maze/modified maze performed without concomitant cardiac surgery (CPT 33254, 33256) — NOT MEDICALLY NECESSARY.

Given less‑invasive alternatives, stand‑alone open procedures should rarely be needed.

Stand‑alone minimally invasive off‑pump maze procedures (CPT 33254, 33255) and hybrid ablation approaches (CPTs 33254, 33258, 33265, 33266) — INVESTIGATIONAL/NOT COVERED.

All other variations outside concomitant on‑pump maze are considered investigational/not covered.

There is no national Medicare coverage determination for maze or related procedures. Review local Medicare LCDs and individual member benefits for coverage specifics.

For certain subgroups (e.g., patients who have failed percutaneous catheter ablation), guideline recommendations are mixed and without unanimous consensus (input in 2013 and subsequent guideline nuance). All other variations of the procedure outside maze during cardiopulmonary bypass with concomitant cardiac surgery are considered investigational/not covered.

Procedure Codes and Device Coding Information

CPT Procedure Codes (referential list)CPT

33254	Operative tissue ablation and reconstruction of atria, limited (e.g., modified maze procedure or hybrid ablation).
33255	Operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure); without cardiopulmonary bypass.
33256	Operative tissue ablation and reconstruction of atria, extensive (e.g., 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).
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).
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).
33265	Endoscopy, surgical; operative tissue ablation and reconstruction of atria, limited (e.g., modified maze procedure), without cardiopulmonary bypass.
33266	Endoscopy, surgical; operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure), without cardiopulmonary bypass.

FDA-cleared/approved radiofrequency and related ablation systems (examples)mixed

EPi-Sense Guided Coagulation System	Manufacturer: AtriCure.
Medtronic DiamondTemp System	Manufacturer: Medtronic.
Cobra Fusion Ablation System	Manufacturer: AtriCure.
Medtronic Cardioblate and Cardioblate Gemini Systems	Manufacturer: Medtronic.
Cardima Ablation System	Manufacturer: Cardima.
Epicor Medical Ablation System	Manufacturer: Epicor Medical.
Isolator Systems	Manufacturer: AtriCure.
Estech COBRA Cardiac Electrosurgical Unit	Manufacturer: Endoscopic Technologies.
Coolrail Linear Pen	Manufacturer: AtriCure.
Numeris Guided Coagulation System with VisiTrax	Manufacturer: nContact Surgical.

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FDA-cleared/approved cryoablation systems (examples)mixed

Cryocare Cardiac Surgery System	Manufacturer: Endocare.
SeedNet System	Manufacturer: Galil Medical.
SurgiFrost XL Surgical CryoAblation System	Manufacturer: CryoCath Technologies (now Medtronic).
Isis cryosurgical unit	Manufacturer: Galil Medical.
Arctic Front Advance / Arctic Front Advance Pro / Freezer Max Cardiac Cryoablation Catheters	Manufacturer: Medtronic.

Provider Actions, Prior Authorization, and Documentation

Prior Authorization

Prior authorization and coding guidance

Procedure CPT codes for maze and modified maze are listed (33254–33266). Concomitant maze procedures performed during other cardiac surgery (codes 33257, 33259) are described as medically necessary when performed during cardiopulmonary bypass with concomitant cardiac surgery; open maze without concomitant cardiac surgery (33254, 33256) is described as not medically necessary. Providers should use the listed CPT codes when requesting prior authorization and ensure the coding reflects whether the procedure is concomitant (list separately in addition to the primary procedure) or stand‑alone.

Codes to include on authorization requests: 33254, 33255, 33256, 33257, 33258, 33259, 33265, 33266.
When performed with another cardiac procedure, use the appropriate concomitant codes (33257, 33258, 33259) listed as add-on (list separately in addition to code for primary procedure).

Note

Device clearance noted — verify authorization requirements

Multiple radiofrequency and cryoablation systems are noted as FDA cleared or approved for cardiac tissue ablation. Confirm the specific device to be used and that device-related coding or supply requirements are addressed in the payer’s prior authorization process.

Clinical Background and Context

Atrial fibrillation (AF) is a supraventricular tachyarrhythmia caused by disordered atrial activation and commonly originates from pulmonary vein myocardial sleeves. Surgical maze (Cox maze) procedures create atrial lesion sets—originally via cut-and-sew techniques on a non‑beating heart during cardiopulmonary bypass—to interrupt aberrant conduction and restore sinus rhythm. These procedures are most commonly performed concomitantly with other cardiac surgery (for example, mitral valve operations or coronary artery bypass grafting). Minimally invasive thoracoscopic and hybrid epicardial–endocardial approaches have evolved as alternatives to address limitations of catheter-only endocardial ablation, but their role is considered investigational or limited except when performed with concomitant cardiac surgery.

Definitions of Procedures and Terms

inv-27: Hybrid ablation — combined thoracoscopic epicardial and percutaneous endocardial approach definition

DefinitionA combined thoracoscopic epicardial and percutaneous endocardial approach in which epicardial surgical ablation is followed by electrophysiologic study and endocardial ablation to complete lesion sets and confirm isolation.

Epicardial componentPerformed via thoracoscopy (or subxiphoid endoscopic access for convergent approach) to deliver lesions on the outer surface of the heart (posterior box, PVI with roof/floor lines, posterior left atrial ablation).

Endocardial componentPercutaneous electrophysiology study with endocardial ablation to check line block, confirm pulmonary vein isolation, and perform additional lesions such as cavotricuspid isthmus ablation as indicated.

TimingEpicardial ablation is followed by endocardial mapping/ablation either immediately during the same anesthetic or staged on separate days per electrophysiology findings.

RationaleCombines strengths of epicardial and endocardial techniques to achieve more complete lesion sets and minimize incomplete lines inherent to each approach alone.

Policy Summary

PayerPremera Bluecross

PolicyCox maze and surgical/hybrid ablation procedures for atrial fibrillation

Policy CodePolicy N/A

Change TypeNo material changes

Effective DateSep 1, 2023

Next Review DateN/A

Key ActionDocument medical necessity and include office visit notes describing the requested maze/modified maze and the concomitant cardiac surgery.

SourceLink

On This Page

Hybrid epicardial–endocardial ablation may be reasonable in symptomatic persistent AF refractory to antiarrhythmic drug therapy, but evidence and recommendations vary; societies note this as a consideration in select patients.

Guideline evidence levels vary (META, RAND, LOE B); practice adoption mixed.

Examples of listed devices include EPi‑Sense, Medtronic DiamondTemp, AtriCure systems, Cobra Fusion, Epicor, and various cryoablation systems.
Verify device use, documentation, and any device-specific authorization rules with the payer.

Note

Coverage guidance and benefit verification

This medical policy guides coverage determinations but does not apply to Medicare Advantage. Providers must verify member-specific benefits and any plan limitations prior to scheduling the procedure.

Check the member benefit booklet or contact customer service to confirm coverage and any applicable limits.
Policy statements guide coverage determinations but member contracts differ in benefits.

Step Therapy

Consideration of less-invasive alternatives

Less‑invasive alternatives such as percutaneous catheter ablation are recognized treatment options and should be considered; guideline guidance references prior antiarrhythmic drug therapy and catheter ablation history when selecting surgical or hybrid approaches.

Catheter ablation is an accepted second-line treatment and may be used as first-line in some patients; consider prior catheter ablation outcomes.
Given less‑invasive options, performing a maze without concomitant cardiac surgery should be rarely needed.

Note

Guideline-based recommendations for concomitant, stand‑alone, and hybrid procedures

Society guidelines indicate concomitant surgical ablation is beneficial when performed during cardiac surgery, and stand‑alone or hybrid surgical ablation may be reasonable for symptomatic persistent AF after failed catheter ablation or intolerance/refractoriness to antiarrhythmic drugs; use guideline-based indications to support authorization requests.

STS, AHA/ACC, and HRS guidance support concomitant surgical ablation to restore sinus rhythm during cardiac surgery.
Stand‑alone or hybrid approaches are reasonable in selected patients after failed catheter ablation or when antiarrhythmic drugs are not tolerated.

Prior Authorization

Provider action: include clinical rationale on requests

If submitting an authorization or claim, include objective clinical rationale and reference to policy statements or guideline recommendations as applicable.

Tie the requested procedure to the patient’s clinical scenario and any guideline recommendation when applicable.

Documentation Required

Required documentation for medical necessity

Medical records submitted for review must document that medical necessity criteria are met and include office visit notes with relevant history and physical describing the requested maze/modified maze and the concomitant cardiac surgery to be performed.

Include office visit notes with history and physical that specifically describe the planned maze/modified maze and the concurrent cardiac operation.

Documentation Required

Guideline-based documentation to support indication

Documentation supporting the indication should reference guideline-based recommendations when relevant (e.g., concomitant surgical ablation during cardiac surgery or stand‑alone/hybrid approaches after failed catheter therapy).

Cite applicable society guidance (STS, AHA/ACC, HRS) and relevant guideline tables when submitting rationale for authorization.

Billing Rule

Verify member benefits and plan limits

Coverage is subject to the limits and conditions of the member’s benefit plan; providers must verify coverage using the member benefit booklet or by contacting customer service prior to procedure scheduling.

This medical policy is a coverage guide; member contracts differ and may impose additional limits.

Denial Risk

Denial risk: stand‑alone open maze not medically necessary

Use of an open maze or modified maze without concomitant cardiac surgery (CPT 33254, 33256) is considered not medically necessary and is at risk for denial if billed as a stand‑alone open procedure.

Do not expect coverage for stand‑alone open maze procedures (33254, 33256) unless documentation demonstrates they meet policy exceptions (none specified).

Denial Risk

Denial risk: minimally invasive standalone and hybrid considered investigational

Stand‑alone minimally invasive, off‑pump maze procedures (33254, 33255) and hybrid ablation procedures (33254, 33258, 33265, 33266) are considered investigational and may be denied when billed as stand‑alone interventions.

Expect investigational denials for stand‑alone minimally invasive/off‑pump and hybrid procedures unless otherwise authorized.

Note

No Medicare NCD — verify local coverage policies

There is no national Medicare coverage determination for these procedures; the absence of an NCD may influence coverage decisions by Medicare contractors or other payers.

Providers should verify local Medicare contractor policies and commercial plan rules when planning procedures.

Note

Historical policy note: nonconcomitant procedures not medically necessary

Policy history states that procedures performed without concomitant cardiac surgery are considered not medically necessary; providers should anticipate legacy coverage positions reflected in prior reviews.

Historical policy language indicates nonconcomitant procedures have been treated as not medically necessary across reviews.

inv-28: Cox maze procedure — definition of open surgical lesion set during cardiopulmonary bypass

DefinitionAn open surgical procedure performed on a non-beating heart during cardiopulmonary bypass that creates atrial lesion sets (originally cut-and-sew) to direct impulses, preserve atrial activation, and block re-entrant circuits causing AF.

Typical indicationIntended for individuals with AF who do not respond to medical or other antiarrhythmic therapies and often performed with correction of structural cardiac conditions (eg, valve repair/replacement).

Lesion set evolutionClassic cut-and-sew Cox maze (III) has evolved to Cox maze IV using radiofrequency or cryoablation to create transmural lesions analogous to the original incisions.

Operative settingPerformed on a non-beating heart during cardiopulmonary bypass as an open surgical operation.

inv-29: Concomitant surgical ablation — definition of surgical ablation at time of another cardiac operation

DefinitionSurgical ablation performed at the time of another cardiac operation (eg, mitral or other cardiac surgery) intended to restore sinus rhythm and reduce recurrent atrial fibrillation.

Guideline supportSTS, HRS, AATS and other society guidelines recommend concomitant surgical ablation during first-time non-emergent mitral and non-mitral operations to restore sinus rhythm and improve outcomes.

Preferred lesion setsBiatrial Cox-Maze III/IV or at minimum pulmonary vein isolation plus left atrial posterior wall isolation are recommended when performed concomitantly with left atrial open cardiac surgery.

Clinical scenariosBeneficial for patients with paroxysmal or persistent AF undergoing left atrial open cardiac surgery regardless of prior antiarrhythmic drug failure or intolerance.

inv-30: Stand-alone surgical or hybrid ablation — definition for procedures performed as primary treatment when not part of other cardiac surgery

DefinitionSurgical or combined epicardial–endocardial (hybrid) ablation procedures performed as the primary treatment for symptomatic atrial fibrillation when not performed concomitantly with other cardiac surgery.

Appropriate scenariosReasonable for symptomatic persistent AF after prior unsuccessful catheter ablation or in those intolerant/refractory to antiarrhythmic drugs; may be reasonable in selected paroxysmal AF after failed catheter therapy.

Preferred technique for stand-aloneBiatrial Cox-Maze III/IV lesion set is preferred for stand-alone procedures per guidance.

Policy stanceStand-alone minimally invasive and hybrid procedures are considered investigational or not medically necessary in certain contexts per payer policy; verify coverage and documentation requirements.

inv-31: Hybrid (convergent) ablation — combined epicardial and endocardial approaches described in trials and registries

DefinitionCombined epicardial and endocardial ablation approaches (simultaneous or staged) described in multiple trials and registries (eg, convergent/hybrid procedures) that pair thoracoscopic or subxiphoid epicardial lesion delivery with percutaneous endocardial mapping and ablation.

VariantsIncludes thoracoscopic epicardial plus percutaneous endocardial approaches and the convergent technique using subxiphoid endoscopic access; timing may be same-session or staged.

Clinical evidenceEffectiveness and safety reported in randomized trials and registry reports; multiple references and convergent-procedure series cited in the literature list.

Procedure goalsIntended to create more complete lesion sets, confirm isolation, and minimize incomplete lines compared with single-modality approaches.