Prognostic value of body mass index and body surface area on clinical outcomes after transcatheter aortic valve implantation

Inverse associations between Body Mass Index (BMI) and Body Surface Area (BSA) with mortality in patients after Transcatheter Aortic Valve Implantation (TAVI) have been reported. This "obesity paradox" is controversial, and it remains unclear which parameter, BMI or BSA, is of greater prognostic value. The aim of this study was to investigate the association of BMI and BSA on short- and mid-term outcomes after TAVI. This prospective, observational study consisted of 917 consecutive patients undergoing TAVI at our center from 2011 to 2014. The association between BMI/BSA and mortality (at 30 days and 1 year) was assessed using restricted cubic spline functions in propensity-adjusted (by Society of Thoracic Surgeons (STS) risk factors) logistic and Cox proportional models, respectively. The median age of the patients was 82.6 years, with a mean STS Predicted Risk of Mortality (STS-PROM) of 6.6 +/- 4.3 %. Throughout the study period (mean follow-up time was 297 days), 150 (16.4 %) patients died; 72 (7.9 %) patients died within 30 days of TAVI. After risk adjustment, the association between body constitution and 30-day mortality was not significant for either measure (BMI p = 0.25; BSA p = 0.32). However, BMI (p = 0.01), but not BSA (p = 0.13), was significantly associated with 1-year survival. There was no association between stroke, vascular complications, or length of stay with BMI or BSA. BMI was associated with survival at 1-year after TAVI. Despite the trend towards implementing BSA in risk score calculation, BMI may be more suitable for the assessment of TAVI patients.