Low body mass index and risk of mortality after mitral transcatheter edge-to-edge repair procedure: The “obesity paradox”

Background: Most patients undergoing the mitral transcatheter edge-to-edge repair (TEER) technique are elderly comorbid patients. Low body mass index (BMI) < 23 kg/m² has been identified in other elderly populations as a risk factor, but has not been studied sufficiently in mitral TEER. Aims: We aimed to study the impact of low BMI (23 kg/m2) on the outcome after mitral TEER. Methods: Patients undergoing first-time TEER for mitral regurgitation at a single tertiary center were included, with the exclusion of patients with preprocedural hemodynamic instability or missing BMI. The primary endpoint was all-cause mortality. Secondary endpoints were long-term major bleeding or admission with heart failure. Results: A total of 120 patients (mean age 76 ± 10 years, 76% men) were included in the study. Thirty-nine (31%) had low BMI. Patients with low BMI had a similar symptomatic benefit as patients with BMI ≥ 23 kg/m² at 1 year regarding decrease in diuretics dose and decrease in New York Heart Association (NYHA) class (p > 0.05). In a multivariable Cox regression analysis, BMI as a continuous variable (hazard ratio [HR]: 0.93 [95% confidence interval, CI: 0.87–0.99], p = 0.03) and low BMI (HR: 1.99 [95% CI: 1.12–3.52], p = 0.02) were associated with the primary outcome. Low BMI was not significantly associated with major bleeding (subdistribution hazard ratio [SHR]: 2.39 [95% CI: 0.96–5.97], p = 0.06) or admission with heart failure (SHR: 1.06 [95% CI: 0.61–1.88], p = 0.83) during follow-up with univariable competing risk regression analysis. Conclusion: Low BMI is a risk factor for mortality after mitral valve TEER, confirming the presence of an “obesity paradox” in this population and should receive attention in patient selection.