AF Ablation, Bariatric Surgery Synergy Seen in the Very Obese

Marlene Busko

July 31, 2019

The results of catheter ablation for atrial fibrillation (AF) in morbidly obese patients are "dramatically" better when preceded by bariatric surgery, a new study suggests.

The analysis is retrospective and from a single center, but the findings are tantalizingly consistent with previously observed improvements in atrial remodeling and AF stabilization associated with weight loss.

In the study, AF recurrences and repeat ablations were both about two-thirds less likely over 3 years in morbidly obese patients undergoing AF ablation who had previously undergone bariatric surgery than in those who instead had enrolled in a weight-management clinic.

AF recurrence was also more likely after ablation in patients with higher levels of glycosylated hemoglobin (HbA1C), which bariatric surgery is known to moderate.

The patients still reaped the benefits of weight loss after bariatric surgery, that is they had a lower AF burden and fewer recurrences, even if their body mass index (BMI) persisted in the "morbidly obese" range, Eoin Donnellan, MD, Cleveland Clinic, told theheart.org | Medscape Cardiology.

The analysis, which defined morbid obesity as a BMI of at least 40 kg/m² or alternatively, a BMI of at least 35 kg/m² with obesity-related complications, such as diabetes, was published July 15 in Europace, with Donnellan as lead author.

The observational study's findings "will require confirmation in a randomized controlled trial," the authors write.

But they also say that "all morbidly obese patients with symptomatic AF refractory to medical therapy should be considered for bariatric surgery evaluation prior to undergoing ablation."

"The important thing with this study is that it shows that regardless of the means of achieving the weight loss, there are the benefits in rhythm control," Prashathan Sanders, MBBS, PhD, University of Adelaide, Australia, told theheart.org | Medscape Cardiology by email.

Although the study was small and nonrandomized, patients in the bariatric-surgery group did lose a good deal of weight, said Sanders, who heads a research group that has long examined risk-factor modification as a way to manage AF. So the study hints that bariatric surgery "may be considered in those with morbid obesity where other methods may have failed."

Sanders is also senior author of an accompanying editorial that lauds the analysis as "the first to demonstrate an improvement in rhythm-related outcomes post-bariatric surgery and AF ablation."

The report concludes "that weight loss surgery should be offered to all morbidly obese patients with AF; however, we feel that more evidence is required to provide further compelling data for this invasive method of AF management, including longer-term follow-up data," the editorialists say.

Besides, they continue, both bariatric surgery and catheter ablation entail risks, and in the current study, conventional weight-management efforts in the control group may have been lacking because those patients lost little weight.

"We do agree that this study provides some promise for a group of patients with otherwise limited management options. But prospective, randomized controlled trials are required, both to establish the safety profile and to elucidate the true effect of bariatric surgery in terms of rhythm control for AF patients, prior to calls for radical shifts in management," they state.

Regarding his own practice, Sanders said: "We work with our patients to achieve 10% weight loss prior to ablation," without surgery. That improves outcomes, but "we have had only a handful of patients in the weight category described in this manuscript."

For the current analysis, Donnellan and colleagues looked at 239 consecutive morbidly obese patients who had undergone AF ablation at their center, with or without preceding bariatric surgery, in the previous 2 years.

Of that group, 51 patients received bariatric surgery — Roux-en-Y gastric bypass in 33, sleeve gastrectomy in 10, and laparoscopic adjustable gastric banding in eight The remaining 188 patients had been enrolled in weight-management clinics.

Patients in both groups had a mean age of 64 years, and about half were male; AF was paroxysmal in about 40% of patients and persistent in 60%.

Donnellan agreed that patients in the medical weight-management group weren't particularly successful in losing weight. "When someone reaches that stage of obesity," he said, "there are other factors, like osteoarthritis, that precludes meaningful weight loss through exercise, and dietary modification will have limited success."

Despite substantial weight loss in the surgery group, averaging 29 kg, the patients were still obese. Their mean BMI had declined from 47.6 kg/m² to 36.8 kg/m² at the time of ablation, and climbed only slightly by end of the follow-up.

However, Donnellan pointed out, they had "significant benefits with respect to sleep apnea severity, glycemic control, inflammatory markers," and natriuretic peptides, a proxy measure of myocardial stretch.

By contrast, the nonsurgical group's mean BMI remained relatively stable, at 42.3  kg/m².

Over the average postablation follow-up of 36 months, 20% of the bariatric-surgery patients and 61% of the standard weight-management group showed AF recurrence (< .0001). The difference remained significant in multivariate analysis and after adjustment by propensity scores.

Repeat ablation was performed in 12% and 44% of patients, respectively.

That the benefits of bariatric surgery went beyond weight loss, Donnellan continued, is consistent with outcomes in the STAMPEDE trial. That study looked at medical weight management of diabetes compared with bariatric surgery and showed that some of the benefits were independent of weight loss.

Weight-loss surgery prior to ablation in the current study, Sanders noted, was also associated with reclassification of AF from persistent to proximal in 22% of the patients, whereas none of the nonsurgical patients showed such reclassification. That, he said, supports findings from the REVERSE-AF study.

The current analysis didn't look at safety outcomes, Donnellan said, but it did show mortality during follow-up as similarly low, at well under 0.1%, in both groups.

Until we have results from prospective randomized trials, the editorialists conclude, morbidly obese patients with AF can be offered individualized risk factor modification, possibly in combination with bariatric surgery, "to achieve sustainable weight loss and improve rhythm-related and quality-of-life outcomes."

Donnellan and the other authors reported no conflicts. Sanders discloses serving on advisory boards for Medtronic, Abbott Medical, Boston Scientific, CathRx, and Pacemate; receiving lecture and/or consulting fees from Medtronic, Abbott Medical, and Boston Scientific; and receiving research funding from Medtronic, Abbott Medical, Boston Scientific, and Microport on behalf of his institution. Disclosures for the other editorial writers are in the report.

Europace. Published July 15, 2019. Abstract, Editorial

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