Effect of BMI on Patients Undergoing Transcatheter Mitral Valve Repair Device Implantation for Severe Mitral Regurgitation

Background: Obesity is a known strong risk factor for cardiovascular diseases including. However, several studies demonstrated an `obesity paradox`, in which patients with higher body mass index (BMI) had better outcomes. There is very limited data on the significance of BMI to outcomes of patients following mitral clip implantation.

Objectives: The aim of this study is to evaluate the influence of BMI on outcomes in patients undergoing mitral clip implantation.

Methods: We studied 148 consecutive procedures of mitral clip implantation, at the Hadassah Medical Center between October 2015 and September 2019. 10 patients lacked the information on BMI and were therefore excluded from this study. Patients were categorized into three groups according to BMI: below 25 kg/m² (normal weight, n=50), 25-30 kg/m² (overweight, n=48), and over 30 kg/m² (obese, n=40). We evaluated 30-day, 1-year and overall mortality after the procedure.

Results: The three groups differed in several baseline characteristics, normal weight patients had higher rates of renal dysfunction, and obese patients had higher rates of hypertension. Despite the differences in baseline characteristics, there were no significant differences among normal weight, overweight and obese patients found in 30-day mortality (0.0%, 4.2%, 7.5%, p=0.161), 1-year mortality (10.0%, 12.5%, 17.5%, p=0.571) or overall mortality (12%, 22.9%, 32.5%, p=0.248). Although there was a trend of worst outcomes in lower BMI patients, it did not reach statistical significance. However, multivariate Cox regression revealed that high BMI levels are associated with higher mortality rates (p=0.032, HR 1.071; 95% CI 1.006-1.140).

Conclusion: The obesity paradox was not demonstrated in patients undergoing transcatheter Mitral valve repair device implantation. In fact, higher BMI was found to be associated with worst outcomes.