Extremes of body mass index do not impact mid-term survival after continuous-flow left ventricular assist device implantation

Abstract

Background: Extremes of body mass index (BMI) are often considered contraindications to use of a left ventricular assist device (LVAD), but data regarding outcomes across the spectrum of BMI are limited. We sought to assess the association of BMI with survival and major morbidity after continuous-flow (CF) LVAD implantation.

Methods: Patients (n = 896) enrolled in the HeartMate II LVAD bridge-to-transplantation and destination therapy trials were divided into 4 BMI groups: underweight (<18.5 kg/m(2)); normal (18.5 kg/m(2) ≤ BMI < 30 kg/m(2)); obese (30 kg/m(2) ≤ BMI < 35 kg/m(2)); and extremely obese (≥35 kg/m(2)). The association of BMI with survival was tested using Kaplan-Meier analysis and proportional hazards regression. Major adverse events were compared using Poisson's regression and chi-square tests.

Results: At implantation, 48 (5%) patients were underweight, 596 (67%) normal weight, 164 (18%) obese and 88 (10%) extremely obese. BMI extremes were associated with differences in creatinine, albumin, age, central venous pressure and etiology. BMI was not associated with survival in the univariate analysis (p = 0.83) or in adjusted models (extremely obese: hazard ratio [HR] 1.29, p = 0.231; obese: HR 0.94, p = 0.723; underweight: HR 1.23, p = 0.452). Underweight patients were more likely to have bleeding events (p < 0.001), whereas extremely obese patients had higher rates of device-related infection (p = 0.041) and rehospitalization (p = 0.014).

Conclusions: Overall survival in patients receiving CF LVAD is similar across BMI categories. Carefully selected patients at both extremes of BMI have good mid-term survival after LVAD and should be considered for LVAD implantation relative to overall risk profile.