Patients with morbid obesity who have symptomatic atrial fibrillation (AF) should be considered for bariatric surgery before undergoing AF ablation, concludes a new retrospective Cleveland Clinic study. The study, published by Europace (2019 Jul 15 [Epub ahead of print]), found a greater than threefold reduction in AF recurrence over three years in patients who underwent bariatric surgery prior to ablation compared with control patients who did not.
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“It is well established that bariatric surgery leads to many short- and long-term cardiovascular benefits,” says senior author Walid Saliba, MD, Director, Cleveland Clinic Atrial Fibrillation Center. “This study indicates that such surgery can also help reduce recurrence of atrial fibrillation following ablation.”
Context: Obesity and AF are intertwined
Dr. Saliba explains that obesity is an independent risk factor for developing AF and is also associated with a host of factors that may promote arrhythmias, including hypertension, obstructive sleep apnea, insulin resistance, inflammation, coronary artery disease and elevated epicardial fat volume. Weight loss following bariatric surgery has been associated with improvements in many of these risk factors, and small studies have associated it with reduced AF events.
Study design and findings
The new investigation, a retrospective observational cohort study, assessed 239 consecutive patients with morbid obesity (body mass index [BMI] > 40 kg/m2, or > 35 kg/m2 with obesity-related complications) who underwent ablation for AF at Cleveland Clinic between 2010 and 2016. Patients had been followed clinically for a mean of 22 months before ablation.
The study arms consisted of 51 patients who had bariatric surgery prior to ablation and 188 who were enrolled in medical weight-management clinics. Mean BMI across the entire cohort at the time of ablation was 41.1 ± 5.3 kg/m2.
Patients were followed for a mean of 36 months after ablation. The study found the following:
- 20% of patients in the bariatric surgery group had recurrent AF after ablation, compared with 61% of patients in the nonsurgical group (P < 0.0001).
- 12% of patients in the surgery group underwent repeat ablation versus 41% in the nonsurgical group (P < 0.0001).
These associations between bariatric surgery and reduced AF recurrence and repeat ablation remained significant after multivariable and propensity score-based analyses.
“Additionally, following ablation, AF was reclassified from persistent to paroxysmal in 22% of patients who underwent bariatric surgery versus none of those who did not,” notes the study’s lead author, Eoin Donnellan, MD, a cardiovascular medicine fellow at Cleveland Clinic.
Obesity-associated AF risk factors
Several pre-ablation factors were identified that significantly increased the risk of AF recurrence following ablation:
- Elevated epicardial fat volume (EFV). Higher EFV, as measured by cardiac CT, was associated with AF recurrence, and mean pre-ablation EFV was significantly lower in the bariatric surgery group.
- Little or no weight reduction. AF recurred in 33% of those whose BMI decreased by > 10% prior to ablation, which compares favorably with the 44% recurrence rate in those whose BMI decreased by < 10% and with the 78% recurrence rate in those whose BMI increased (P < 0.0001). Mean BMI decreased from 47.6 + 3 to 36.8 + 7.0 kg/m2 prior to ablation in the bariatric surgery group, whereas it remained unchanged (at 42.3 kg/m2) in the nonsurgical group.
- Little or no improvement in glycated hemoglobin (HbA1C). AF recurred in 12% of patients who had a pre-ablation HbA1C reduction of at least 10% compared with 65% of those whose HbA1C fell by less than 10% and compared with 86% of those whose HbA1C increased (P < 0.0001).
Best evidence yet of benefits specific to ablation outcomes
The authors note that this study adds to mounting evidence of the cardiovascular benefits associated with obesity reduction demonstrated in other investigations, including the Cleveland Clinic-led STAMPEDE trial (N Engl J Med. 2012;366:1567-1576). That randomized controlled study found that diabetes risk factors significantly improved following bariatric surgery, with benefits still enduring through five-year follow-up (N Engl J Med. 2017;376:641-651).
“This new study by Drs. Saliba, Donnellan and colleagues adds to the existing literature by indicating that bariatric surgery is associated with a dramatically reduced rate of recurrent AF following ablation in patients with morbid obesity,” observes Steven Nissen, MD, a senior investigator with the STAMPEDE trial and Chief Academic Officer of Cleveland Clinic’s Miller Family Heart & Vascular Institute. “It is the first reported study to show a reduction in post-ablation recurrence rates in the wake of bariatric surgery.”
“Ideally, these results should be confirmed in a multicenter randomized controlled trial,” notes Oussama Wazni, MD, Section Head of Electrophysiology and Pacing at Cleveland Clinic. “In the meantime, however, we would recommend that individuals with treatment-refractory morbid obesity consider evaluation for bariatric surgery before AF ablation, as the overall evidence for cardiovascular benefits is strong.”