The obesity paradox in patients undergoing transcatheter aortic valve implantation: is there any effect of body mass index on survival?

BACKGROUND: Conflicting results have been presented regarding the influence of body mass index (BMI) on outcomes among patients undergoing transcatheter aortic valve implantation (TAVI). AIMS: To investigate the impact of BMI on clinical outcomes after TAVI. METHODS: A total of 148 consecutive patients were categorised using baseline BMI according to the World Health Organization criteria. Baseline patient characteristics, frailty, and procedural and clinical outcomes including 30-day and 12-month all-cause mortality were compared between the BMI categories. Patients were followed up for a median of 460.0 (182.0-1042.0) days. RESULTS: Obesity was diagnosed in 37 (25.2%) patients, 73 (49.7%) patients were overweight, and 37 (25.2%) had normal weight. Prevalence of lower frailty as assessed by five-metre walk test was confirmed in obese patients as compared to other groups. A trend towards a lower rate of in-hospital bleeding complications (18 [48.6%] vs. 21 [28.8%] vs. 9 [24.3%] in normal-weight, overweight, and obese patients, respectively; p = 0.06) and less frequent blood transfusions (18 [48.6%] vs. 17 [23.3%) vs. 8 [21.6%]; p = 0.016) was observed in overweight and obese groups. The rate of grade 3 acute kidney injury was lowest in the overweight group (4 [10.8%] vs. 1 [1.4%] vs. 3 [8.1%]; p = 0.05). There was no difference between the groups in terms of 30-day all-cause mortality (p = 0.15). However, 12-month all-cause mortality was lowest in obese pa-tients (12 [32.4%] vs. 10 [13.7%] vs. 2 [5.4%]; p = 0.004). Increase in BMI was independently associated with lower all-cause mortality (hazard ratio [95% confidence interval] per 1 kg/m2 increase: 0.91 [0.845-0.98]; p = 0.018). CONCLUSIONS: Increased BMI was independently associated with survival benefit after TAVI.