Does "Obesity Paradox" Apply for Patients Undergoing Transcatheter Aortic Valve Replacement?

BACKGROUND

Data is controversial regarding the existence of an "obesity paradox" in patients undergoing Transcatheter Aortic Valve Replacement (TAVR). We sought to investigate the prognostic value of the body mass index (BMI) on outcomes following TAVR.

METHODS

This is an observational, single-center study involving all patients who underwent TAVR from 2009 to 2019. BMI was calculated in all patients before TAVR. The cohort was subdivided into four groups: underweight (<20 kg/m), normal weight (≥20 to <25 kg/m), overweight (≥25 to <30 kg/m) and obese (≥30 kg/m). The main endpoint was all-cause 30-day and one-year mortality.

RESULTS

A total of 412 patients (mean age 79.6 ± 7.8 years, mean STS score 5.3 ± 3.6) were included. Patients were grouped as follows: underweight (n = 35, 8.5%), normal weight (n = 121, 29.4%), overweight (n = 140, 34%) and obese (n = 116, 28.1%). Obese patients were younger, included more females and had lower STS score than the rest of the cohort whereas underweight patients were older, had higher STS score, more chronic kidney disease, more left ventricular dysfunction and more often underwent non-transfemoral TAVR. BMI predicted 30-day survival (AUC:0.692 [95%CI 0.522-0.862]; p = 0.030) with an optimal cut-off of 24.4 (sensitivity = 66.6%, specificity = 63.6%). On multivariate analysis, higher BMI trended toward lower 30-day mortality (HR = 0.87 [95%CI 0.75-1.01]; p = 0.071). Thirty-day mortality was higher in the underweight group (8.3%) in comparison with other BMI subgroups (normal weight 2.5%, overweight 1.4%, obese 0.9%; p = 0.045). However, no significant difference was found after adjustment of confounders (all p = NS). BMI did not predict one-year mortality. No significant difference in one-year survival was observed between the four BMI subgroups (log rank p = 0.925).

CONCLUSION

BMI could represent an interesting prognostic tool for short-term mortality in patients undergoing TAVR. BMI < 20 kg/m was associated with higher 30-day mortality. Symptoms improved similarly in obese patients compared to lower BMI patients. For 30-day survivors, no evidence of the existence of an obesity paradox was observed in this cohort.