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/m2), overweight (≥25 to <30kg/m2) and obese (≥30kg/m2). 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.
Keywords: Aortic stenosis; Body mass index; Mortality; Obesity paradox; Transcatheter aortic valve implantation.
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