Current recommendations for concomitant surgical ablation in atrial fibrillation (AF) suggest a class IIb indication for asymptomatic cases and class IIa for those with symptomatic, clinically significant AF. Conversely, left atrial appendage closure (LAAC) has gained traction since the publication of the LAAOS III trial, achieving a class IIa recommendation. While a synergistic effect from combining LAAC with ablation is conceivable, various factors lead to a selective approach for LAAC alone in patients undergoing CABG, and even then, not universally applied:

Firstly, the fact that discontinuation of oral anticoagulation is generally not recommended makes invasive AF treatment less appealing. However, performing LAAC in this patient group, most of whom have non-valvular AF and are managed with antiplatelet therapy, may allow for anticoagulation discontinuation in those experiencing bleeding complications or other contraindications, especially in younger patients with a CHA2DS2VAsc score < 2.

Secondly, many surgical teams prefer off-pump CABG. This, combined with the complexity and suboptimal outcomes of epicardial-only ablation, can lead to abstaining from AF treatment altogether or limiting it to epicardial approaches, such as the clip devices (AtriClip®) that have recently become more widely adopted. Some teams report complications with graft geometry on the lateral wall due to interference from these larger clips, recommending excision-suture techniques preferable in cardiopulmonary bypass (CPB) settings. When CPB is employed, intracavitary ablation increases complexity, duration, and procedural risk, making it less comparable to isolated CABG outcomes in the short term.

Thirdly, the long-term benefit of concomitant ablation remains uncertain due to high recurrence rates. Indeed, some argue that LAAC is included as part of ablation protocols due to its potential benefit, making it a preferred intervention among ischemic heart disease patients with AF. However, patients in this population, mostly without underlying valvular disease, may show outcomes closer to those undergoing isolated AF ablation. Notably, 89% of patients in this study had paroxysmal AF.

To address these questions, the authors analyzed data from Medicare®-affiliated American centers involving patients aged 65 or older who underwent CABG for AF between 2018 and 2020. A total of 19524 patients were distributed into three groups: 11508 (58.9%) underwent isolated CABG, 4541 (23.3%) underwent CABG + LAAC, and 3475 (17.8%) received CABG + LAAC + ablation. After robust adjustment using double risk analysis with a multivariate Cox model and Fine-Gray time-to-event analysis, both perioperative and three-year survival outcomes were evaluated.

At 30 days, isolated LAAC was associated with a significantly lower rate of stroke readmission compared to no AF procedure (HR = 0.65; p = 0.10). However, isolated LAAC was linked to higher readmission rates for heart failure (previously reported in other studies, likely associated with impaired natriuresis driven by natriuretic peptides) compared to the LAAC + ablation and isolated CABG groups. Other perioperative complications such as mortality, renal failure, or perioperative bleeding showed no significant differences between groups or attributable etiological explanations.

At follow-up, LAAC + ablation and isolated LAAC with CABG reduced stroke readmission rates compared to no concomitant AF treatment (HR = 0.74, p = 0.49; HR = 0.75, p = 0.03, respectively). However, only LAAC + ablation, and not isolated LAAC (HR = 0.86, p = 0.16 vs. HR = 0.97, p = 0.57, respectively), was associated with improved survival over isolated CABG.

The authors conclude that, in candidates for CABG and AF, concomitant LAAC + ablation reduces stroke risk and improves survival compared to no concomitant procedure or LAAC alone.

COMMENTARY:

The findings of this study are particularly novel and, despite limitations, illustrate the clear benefits of offering a comprehensive treatment for the underlying cardiac pathology in patients undergoing surgery. For those of us who have long believed in the benefits of ablation, these results are encouraging, affirming our choice to continue with the procedure despite skepticism, which may take forms such as “You know what we do with AF patients here?… Just give them warfarin!”

It is unfortunate that, being a registry-based study, there is no available data on the type of ablation performed (epicardial/intracavitary, lesion pattern, energy source, etc.), AF recurrence rates (and measurement method), or the exact LAAC procedure. Nonetheless, the large patient volume lends the study statistical power, and hard outcomes such as survival and stroke rates make the conclusions credible, potentially prompting a shift in surgical practice for those still hesitant or newly skeptical after the surge a decade ago. In fact, this study answers three key questions:

Firstly, LAAC reduces stroke rates, making it essential to seize the opportunity to perform it on any patient with AF, regardless of future anticoagulation needs, even with agents of superior efficacy and safety profiles like direct oral anticoagulants, which will likely become standard in this patient group.

Secondly, the synergy between both procedures is clear, with only the combination of ablation and LAAC improving survival, likely by reducing heart failure rates and preventing or limiting the progression of functional mitral and/or tricuspid valve disease. If off-pump CABG is preferred, these findings open the door to exploring hybrid approaches, such as pulmonary vein isolation or box lesions performed during surgery and completed later with percutaneous techniques, as they yield the best results for isolated AF patients. Beyond devices like the bipolar radiofrequency clamp (e.g., AtriCure® Isolator®) or band ablation systems (e.g., Stetch Cobra®), the EPi-Sense® system performs left atrial posterior wall ablation via pericardioscopy and can be integrated into the surgical field, whether by median sternotomy or minimally invasive CABG approaches.

Thirdly, this study shows that the profile of patients suitable for concomitant ablation with CABG is favorable, with most having paroxysmal AF, where the benefits of complete AF treatment (ablation + LAAC) surpass those of mere LAAC, clarifying previous uncertainties.

In conclusion, careful, well-executed work highlights the consequences of leaving cardiac disease untreated, even in the absence of apparent structural substrates. Properly designed studies allow us to maintain faith in these techniques and to revive procedures where patient selection is key to achieving successful outcomes. Reducing our craft to cutting and stitching—short of performing the classical Cox maze—may have led to the current situation, where retooling, adopting new technology, and finding ways to demonstrate the extensive potential of our therapeutic capabilities could well be the future.

REFERENCE:

Mehaffey JH, Hayanga JWA, Wei LM, Chauhan D, Mascio CE, Rankin JS, et al. Concomitant Treatment of Atrial Fibrillation in Isolated Coronary Artery Bypass Grafting. Ann Thorac Surg. 2024 May;117(5):942-949. doi: 10.1016/j.athoracsur.2023.11.034.