Is Prophylactic Ablation for Atrial Fibrillation Warranted During Mitral Surgery
Christopher Mehta1, Patrick M. McCarthy1, Adin-Cristian Andrei2, Jane Kruse3, Andrei Churyla1, S.Chris Malaisrie1, Duc T Pham1, James L Cox1
1Northwestern University Feinberg School of Medicine, Chicago, IL;2Northwestern University, Chicago, IL;3Northwestern Medicine, Chicago, IL
Atrial fibrillation (AF) ablation is recommended during mitral valve (MV) surgery for patients with pre-operative AF. We sought to determine the incidence and risk factors for de novo AF in patients without pre-operative AF.
From 2004-2014, 1288 patients had MV +/- other cardiac procedures without known pre-operative AF. Of those, 930 patients had follow-up rhythm information available at 90 days or more after the index surgery, as determined by query of our longitudinal database. AF-free survival, de novo AF, and death probability estimates were obtained using a semi-competing risks multi-state model. Univariable and multivariable risk factors for developing AF were identified using the Fine-Gray model.
The 5- and 10-year incidence of de novo AF was 14% and 23%, respectively (Figure 1). Univariable risk factors for developing AF were older age, more comorbidities, more complex operations, more tricuspid valve regurgitation, higher CHA2DS2-VASc score, and congestive heart failure (CHF) (all p<0.05). In univariate analysis patients with degenerative mitral regurgitation were less likely to develop AF (HR 0.4, 95% CI (0.24, 0.65), p<0.001) compared to other etiologies. Multivariable risk factors for de novo AF were tricuspid valve surgery (hazard ratio HR=1.84, 95% CI (1.23, 2.75), p=0.003), aortic valve surgery (HR 1.66 (1.09, 2.52), p=0.017), and older age (HR 1.03 (1.02, 1.04), p<0.001). Low preoperative EF and CHF were not significantly associated with the risk of AF. Development of de novo AF was not significantly associated with lower overall survival (p=0.4).
A steady rate of de novo AF develops after MV surgery. An adequately controlled randomized trial to detect a 5-year 40% reduction of AF with 80% power at 2-sided 5% α-level, would require 2392 patients which is not clinically feasible. Given that older age is a risk factor for de novo AF, a targeted trial of prophylactic ablation for high risk patients, such as those ≥ 65 years with multiple valve surgery, may be a more practical approach. We found no evidence at this time to support the practice of performing prophylactic AF surgery in MV surgery patients without a prior history of AF.
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