Aetna modified CPB 0225 for the Maze procedure, effective November 27, 2025. Here's what billing teams need to know.
Aetna, a CVS Health company, updated its Maze procedure coverage policy under CPB 0225 in the Aetna system. The change affects CPT codes 33254, 33256, 33257, 33259, and 33416 — the covered codes for atrial ablation and septal myectomy — and draws a hard line around minimally invasive and off-pump approaches. If your cardiac surgery program bills these codes, audit your charge capture and documentation before treating this as a 2025 renewal.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Aetna |
| Policy | Maze Procedure — CPB 0225 |
| Policy Code | CPB 0225 |
| Change Type | Modified |
| Effective Date | November 27, 2025 |
| Impact Level | High |
| Specialties Affected | Cardiac Surgery, Electrophysiology, Cardiothoracic Surgery |
| Key Action | Confirm all Maze procedure claims use covered CPT codes with cardiopulmonary bypass — off-pump approaches (CPT 33255, 33258, 33265, 33266) will deny |
Aetna Maze Procedure Coverage Criteria and Medical Necessity Requirements 2025
The Aetna Maze procedure coverage policy under CPB 0225 covers the procedure only when performed with cardiopulmonary bypass on a beating heart. That detail matters. It immediately disqualifies a wide range of minimally invasive approaches, regardless of how good the clinical outcomes literature looks.
To meet medical necessity, the member must have atrial fibrillation or flutter, plus at least one of these three conditions:
| # | Covered Indication |
|---|---|
| 1 | Drug intolerance — the member cannot tolerate the side effects of antiarrhythmic therapy. Aetna requires adequate documentation of the nature and extent of the intolerance. Vague chart notes will not hold up on review. |
| 2 | Hemodynamic consequences — the member suffers hemodynamic consequences of chronic atrial fibrillation or flutter despite adequate attempts at medical management. "Adequate" is the operative word. Your documentation needs to show a real trial of medical therapy, not just a preference for surgery. |
| 3 | High-risk for thromboembolism — evidenced by either a previous episode of thromboembolism (with other embolic sources ruled out) or documented long-standing atrial fibrillation in a member with mitral valve disease undergoing open surgical repair of the mitral valve. |
That third criterion is the one that catches billing teams off guard. The mitral valve disease pathway requires two things at once: long-standing AF documentation and a concomitant open mitral valve repair. If the mitral repair is the only reason the Maze is happening, your chart needs to prove the AF has been long-standing — not just present.
Aetna also covers concomitant Maze and septal myectomy (CPT 33416) as medically necessary for hypertrophic obstructive cardiomyopathy (ICD-10 I42.1) plus refractory atrial fibrillation or flutter. This is the only dual-procedure combination Aetna blesses under this coverage policy. Document both diagnoses clearly.
Prior authorization is the practical reality for procedures at this cost and complexity level. Even when medical necessity criteria are met, your prior auth submission needs to mirror the specific qualifying criteria above — not just say "AF refractory to medical management." Aetna reviewers will look for the exact clinical basis.
Aetna Maze Procedure Exclusions and Non-Covered Indications
This is where the policy draws its sharpest line.
Aetna classifies minimally invasive, off-pump Maze procedures as experimental, investigational, or unproven. That includes the hybrid Maze, the Convergent hybrid procedure, and thoracoscopic off-pump surgical ablation (TOPS). The policy states directly that effectiveness has not been established for these approaches.
CPT 33255 (extensive atrial ablation without cardiopulmonary bypass), CPT 33258 (the add-on version at time of other cardiac procedures, without bypass), CPT 33265, and CPT 33266 (endoscopic approaches) are all explicitly not covered under this policy. Claims for these codes will not generate reimbursement under CPB 0225. These are not edge cases or gray zones — they are listed as non-covered.
The real issue here is that off-pump and hybrid approaches have grown in clinical use over the past several years. Some surgeons prefer them. Some patients are better candidates for them. Aetna does not care — at least not under this policy. If your cardiac surgery team has shifted toward TOPS or hybrid Maze approaches, you have a coverage gap with Aetna members that needs a direct conversation with your clinical and compliance teams.
The policy also excludes the Maze procedure for all indications not specifically listed. The covered indications are narrow. If a surgeon is using the Maze for something outside those three criteria, it will not meet Aetna's definition of medical necessity.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| AF/flutter — drug intolerance with documented side effects | Covered | 33254, 33256, 33257, 33259 | Requires adequate documentation of intolerance nature and extent |
| AF/flutter — hemodynamic consequences despite medical management | Covered | 33254, 33256, 33257, 33259 | Must show adequate trial of medical management |
| AF/flutter — prior thromboembolism (other sources ruled out) | Covered | 33254, 33256, 33257, 33259 | Other embolic sources must be formally ruled out |
| Long-standing AF with mitral valve disease at time of open mitral repair | Covered | 33254, 33256, 33257, 33259 | Concomitant open mitral repair required; AF must be long-standing |
| Hypertrophic obstructive cardiomyopathy + refractory AF/flutter | Covered | 33416, 33254, 33256 | Maze + septal myectomy both covered; both diagnoses required |
| Minimally invasive off-pump Maze (hybrid, Convergent, TOPS) | Experimental / Not Covered | 33255, 33258, 33265, 33266 | All off-pump approaches excluded under CPB 0225 |
| Maze for indications outside those listed | Not Covered | N/A | All other indications are excluded |
Aetna Maze Procedure Billing Guidelines and Action Items 2025
| # | Action Item |
|---|---|
| 1 | Audit every pending Maze claim against the on-pump requirement. CPT 33256 (extensive Maze with cardiopulmonary bypass) and CPT 33254 (limited/modified Maze) are your covered open-surgery codes. If any claim uses 33255 or 33266 instead, it will deny. Pull your charge capture for Q4 2025 and compare the codes against the operative reports. |
| 2 | Flag off-pump cases before they hit the claim. CPT 33265 and 33266 (endoscopic atrial ablation) are not covered under CPB 0225. Neither is 33255. If your surgeons are documenting off-pump or thoracoscopic approaches, your billing team needs to know before the claim goes out — not after the denial comes back. |
| 3 | Review documentation standards for the drug intolerance pathway. Aetna explicitly requires documentation of "the nature and extent" of drug intolerance. That is more than a checkbox. The chart needs to show which drug was tried, what side effects occurred, and why the patient cannot continue. Generic notes like "antiarrhythmic not tolerated" will not survive a medical necessity review. |
| 4 | Build a documentation checklist for the mitral valve + AF pathway. This indication has two hard requirements: long-standing AF and concomitant open mitral repair. Your prior auth team and your coders both need a trigger that checks for both before submitting. Create a simple checklist that matches the policy criteria. |
| 5 | Confirm the septal myectomy combination is coded correctly. When billing concomitant Maze and septal myectomy for hypertrophic obstructive cardiomyopathy with refractory AF, use CPT 33416 alongside the appropriate atrial ablation code. ICD-10 I42.1 covers obstructive hypertrophic cardiomyopathy. Both diagnoses need to appear — one supports the myectomy, one supports the Maze. Missing either will create a claim denial. |
| 6 | Update your payer-specific billing guidelines for Aetna effective November 27, 2025. This policy is live. Any Maze procedure billed to Aetna after that date is subject to these criteria. If you have not already updated your internal billing guidelines to reflect the off-pump exclusion and the specific medical necessity criteria, do that now. |
| 7 | Talk to your compliance officer if your program uses hybrid or Convergent approaches. If your cardiac surgery team has been billing Aetna for hybrid Maze or Convergent procedures, you may have exposure. Pull your claims history back to the effective date and cross-reference against these exclusions. Your compliance officer should know about this before a payer audit surfaces it first. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for the Maze Procedure Under CPB 0225
Covered CPT Codes (When Selection Criteria Are Met)
| Code | Type | Description |
|---|---|---|
| 33254 | CPT | Operative tissue ablation and reconstruction of atria, limited (e.g., modified maze procedure) |
| 33256 | CPT | Operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure); with cardiopulmonary bypass |
| +33257 | CPT | Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s); limited (add-on) |
| +33259 | CPT | Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s); extensive (add-on) |
| 33416 | CPT | Ventriculomyotomy (-myectomy) for idiopathic hypertrophic subaortic stenosis (e.g., asymmetric septal hypertrophy) |
Not Covered / Experimental CPT Codes
| Code | Type | Description | Reason |
|---|---|---|---|
| 33255 | CPT | Operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure); without cardiopulmonary bypass | Not covered for indications listed in CPB 0225 |
| +33258 | CPT | Operative tissue ablation and reconstruction of atria, performed at the time of other cardiac procedure(s); without cardiopulmonary bypass (add-on) | Not covered for indications listed in CPB 0225 |
| 33265 | CPT | Endoscopy, surgical; operative tissue ablation and reconstruction of atria, limited (e.g., modified maze procedure) | Not covered — endoscopic/minimally invasive approach |
| 33266 | CPT | Endoscopy, surgical; operative tissue ablation and reconstruction of atria, extensive (e.g., maze procedure), without cardiopulmonary bypass | Not covered — endoscopic/minimally invasive approach |
Key ICD-10-CM Diagnosis Codes
| Code | Description |
|---|---|
| I42.1 | Obstructive hypertrophic cardiomyopathy |
| I48.0 | Atrial fibrillation, chronic |
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