Obese AFib patients benefit less from catheter ablation

A combo of cryoballoon ablation and novel oral anticoagulants (OACs) might be a more effective treatment route than standard care for obese AFib patients, who, according to an Oct. 4 study, are less likely to benefit from traditional catheter ablation in the long-term.

Catheter ablation is widely regarded as an effective treatment option for patients with atrial fibrillation, Rui Providencia, MD, PhD, and colleagues reported in the Journal of the American Heart Association, snagging a Class I indication in symptomatic patients with drug-refractory AFib and boasting a relatively high success rate. Freedom from AFib or atrial tachycardia relapse exceeds 70% at 12 months for paroxysmal AFib and hovers around 50% at 18 months for patients with persistent AFib.

But researchers remain unsure of how—and even if—BMI influences the outcomes of AFib ablation, the authors said. Data on the performance of novel OACs and cryoballoon ablation in overweight patients are few and far between.

“Addressing correctable causes of AFib relapse is of interest, as this may allow improvement of the outcomes of this procedure,” Providencia, of the Clinic Pasteur in Toulouse, France, and co-authors wrote. “Preliminary evidence from small studies suggested that obese patients present high relapse rates. However, a meta-analysis has shown that this could happen as a result of associated comorbidities in overweight patients and not BMI itself.”

Providencia et al. studied 2,497 consecutive patients who underwent catheter ablation of AFib at one of seven high-volume centers in Europe between 2014 and 2015. They were stratified according to BMI—either normal weight (BMI under 25), pre-obese (BMI between 25-30), obese (BMI between 30-35) or morbidly obese (BMI over 35).

The authors reported that more pre-obese and obese patients presented with comorbidities like hypertension, diabetes and sleep apnea and had higher rates of non-paroxysmal AFib ablation than their counterparts. Rates of atrial 12-month arrhythmia relapse increased with BMI:

  • 35.2% in normal-weight patients
  • 35.7% in pre-obese patients
  • 43.6% in obese patients
  • 48% in morbidly obese patients

Providencia and colleagues said BMI was an independent predictor of relapse over 18.8 months of follow-up, yielding a hazard ratio of 1.01 per kg/m2. It wasn’t, however, a predictor of any reported complications.

“BMI remained an independent predictor of atrial arrhythmia recurrence even after adjustment for AFib type, suggesting that response to catheter ablation is worse not only because these patients present with more advanced forms of AFib, but also because of obesity-related factors,” the authors said.

Using novel OACs and cryoballoon ablation was both safe and effective in the obese population, finding the approach comparable to a combination of vitamin-K antagonists and radiofrequency ablation, the study revealed.

“Our findings show that, irrespective of associated comorbidities, a higher BMI is associated with lower success rate in terms of freedom from atrial arrhythmia over long-term follow-up,” Providencia et al. wrote. “Systematic measures leading to a reduction in BMI should play an important role before and after the procedure.”