Prognostic value of body mass index in transcatheter aortic valve implantation: A "J"-shaped curve.

Objectives: We aimed to determine whether body mass index (BMI) is a prognostic indicator for long-term, all-cause mortality in patients undergoing transcatheter aortic valve implantation (TAVI).

Background: Obesity in patients with established cardiovascular disease has previously been identified as an indicator of good prognosis, a phenomenon known as the "obesity paradox". The prognostic significance of BMI in patients with severe aortic stenosis (AoS) undergoing TAVI is a matter of current debate, as published studies are scarce and their results conflicting.

Methods: This is an observational, retrospective study involving 770 patients who underwent TAVI for AoS. The cohort was divided into three groups based on their BMI: normal weight (≥18.5 to <25kg/m), overweight (≥25 to <30kg/m) and obese (≥30kg/m). The predictive effect of BMI on all-cause mortality 3years following TAVI intervention was analysed using a Cox regression.

Results: 155 patients died during follow-up. The overweight group (n=302, 38.97%), experienced a lower mortality rate compared to the normal weight and obese groups (15.9% vs 25.7% and 21.0%, respectively [log-rank p-value=0.036]). After adjustment by logistic EuroSCORE, being overweight was found to be an independent protective factor against mortality (HR: 0.63 [95% CI: 0.42 to 0.94], p=0.024). This was not the case for obesity (HR: 0.92 [95% CI: 0.63 to 1.35], p=0.664). We therefore describe for the first time, a "J-shaped" regression curve describing the relationship between BMI and mortality.

Conclusions: BMI is a predictive factor of all-cause mortality in AoS patients undergoing TAVI. This relationship takes the form of a "J-shaped" curve in which overweight patients are associated with the lowest mortality rate at follow-up.