Impact of BMI on outcomes of atrial fibrillation ablation

Takeaway

• Obese patients present with a more adverse comorbidity profile, more advanced forms of atrial fibrillation (Afib), and have lower chances of being free from Afib relapse after ablation.
• The use of novel oral anticoagulants (NOACs) and cryoballoon ablation is safe and have comparable efficacy to vitamin-K antagonists (VKA) and radiofrequency ablation in patients with obesity.

Why this matters

• Combination of cryoballoon ablation and NOACs may be an alternative treatment option in patients with obesity.

Study design

• Study of 2497 patients (aged >18 years) undergoing catheter ablation of Afib in 7 European high volume centres during 2014-2015.
• Patients were stratified according to body mass index (BMI) as:
  • normal weight (<25 kg/m²; n=711),
  • pre-obese (25-30 kg/m²; n=1092),
  • obesity (30-35 kg/m²; n=508) and
  • morbid obesity (≥35 kg/m²; n=186).
• Funding: None disclosed.

Key results

• Prevalence of non-paroxysmal forms of Afib increased alongside with BMI (P<.001) and the prevalence of risk factors for coronary and cerebrovascular disease was higher in patients with higher BMI (P<.001).
• At 12 months, the rate of relapse increased progressively across the 4 BMI classes (all, P<.001): 35.2%, 35.7%, 43.6% and 48.0% in normal weight, pre-obese, obese, and morbidly obese patients, respectively.
• During a median follow-up of 18.8 months, BMI was an independent predictor of relapse (HR, 1.01 [95% CI, 1.00-1.02] per kg/m²; P=.017).
• NOACs and cryoballoon ablation were comparable to VKA and radiofrequency ablation in obese patients.
  • Radiofrequency vs cryoballoon ablation:
    • all complications (4.6% vs 7.9%),
    • cardiac tamponade (1.0% vs 0.5%),
    • stroke (0.2% vs 0.5%) and
    • vascular complications (1.6% vs 2.6%).
  • NOACs vs VKA:
    • cardiac tamponade (0.6% vs 1.0%),
    • stroke (0% vs 0.4%) and
    • vascular complications (1.7% vs 2.0%).

Limitations

• Study may not represent the type of ablation activity performed in other centres with lower caseloads.