Background:

Cryoballoon-based (Cryo) pulmonary vein isolation (PVI) is a standard therapy for patients (pts) with atrial fibrillation (AF). We sought to assess the impact of body mass index (BMI) on AF recurrence and procedural characteristics (e.g. procedure duration, number of freezes, use of contrast medium, fluoroscopy dose).

Methods:

All pts undergoing de novo Cryo PVI between January 2018 and August 2019 at the University Hospital of Cologne were included in this retrospective analysis. We predefined a subgroup analysis of normal weight BMI <25kg/m², pre-obesity 25-30kg/m², obesity stage I 30-35kg/m² and obesity stage II ≥35kg/m².

Results:

In this period 320 Cryo PVI (61% of all de novo PVI) were successfully performed (average age 65.3 ± 11.4 years, 63% male, 60% paroxysmal AF (PAF), 40% persistent AF (Pers AF)). The BMI distribution (BMI <25, 25-30, 30-35, ≥35 kg/m²) was 99 (31%), 119 (37%), 71 (22%) and 31 (10%) pts.

In pts with severe obesity (BMI≥35) the total freeze duration to achieve PVI is significantly longer as compared to normal weight pts (BMI<25 kg/m² 968.6 s vs BMI≥35 kg/m² 1155.9 s, p=0.006). In addition, in pts with a BMI≥35 there was a significant higher number of freezes needed to achieve PVI compared to normal weight pts (BMI<25 kg/m² 5.6 vs BMI≥35 kg/m² 6.4 freezes, p=0.0492). Significantly more contrast medium (CM) (BMI<25 61.4 ml vs BMI≥35 80.0, p=0.02) and higher fluoroscopy doses were detected in severely obese pts compared to normal weight pts (BMI<25 449.0 µGy x m² vs BMI≥35 1522.3 µGy x m², p<0.001). The total procedure time and overall complication rate not significantly differ regardless of the BMI group. Pts with a higher BMI had no increased risk of AF recurrence after twelve months (BMI<25: 25% vs BMI≥35: 25%). In comparison PAF to Pers AF there were statistically significant differences regarding the AF recurrence rates (PAF 21%, Pers AF 32%, p=0.047).

Conclusion:

A de-novo Cryo PVI in obese and severely obese pts is safe and effective. However, to achieve complete PVI the Cryo-freeze duration is significantly longer in severely obese pts (BMI≥35) as compared to normal weight pts (BMI<25). Therefore, increasingly used curtailed Cryo-protocols might not be applicable for severely obese pts. Also, significantly more contrast medium is used in BMI≥35 pts, hence renal function should be monitored continuously after Cryo PVI. Based on the follow up, recurrences rate of AF in obese pts after Cryo PVI seems to be comparable to normal weight pts and to previous data.