Heart Transplant Outcomes in Obese Patients BMI 35-39.9

Abstract

The 2016 ISHLT revised cardiac transplantation listing criteria has recommended patients to achieve a body mass index (BMI) <35 kg/m² prior to listing. Although some studies show that patients with pre-transplant BMI>35 show poorer outcome post-transplant, there is limited data on the BMI group of 35-39.9. This study aims to determine the relationship between post-transplant outcomes and a pre-transplant listing BMI of 35-39.9 as compared to a BMI <35. A retrospective cohort analysis of patients stratified by BMI subgroup was performed of 23,009 adult heart transplant patients from 2009-2018 using the United Network for Organ sharing database. Patients with BMI of 35-39.9 post-transplant outcomes were compared to patients with BMI <35. Kaplan-Meier analysis univariate and multivariate Cox proportional-hazards models were used to determine the prognostic factors associated with mortality at 90 days, 1 year and 5 year after transplantation. Patients with a BMI 35.0-39.9 had post-transplant survival of 92.4% at 90 days, 89.3% at 1 year and 74.5% at 5 years, compared to patients with a BMI < 35.0 whose post-transplant survival were 94.6% at 90 days, 91.3% at 1 year, and 79.3% at 5 years. The proportion of stroke events was 2.7%, 2.1%, and 2.2% for BMI <35, 35-39.9, and ≥40, respectively, with no statistically significant difference among the BMI groups for stroke events before discharge. There was a statistically significant difference in the proportion of dialysis events between the BMI < 35 and BMI 35-39.9, and BMI ≥40 group, with rates of 10.5%, 14.0%, and 16.2% for the BMI <35, 35-39.99, and ≥40 groups respectively. There was no statistically significant differences in the proportion of acute rejection events prior to discharge, with rates of 19.6%, 21.2% and 24.5% for BMI<35, 35-39.9, and ≥ 40, respectively. Although a statistically significant increase in mortality was observed between the BMI < 35 and BMI 35-39.9 groups, this difference may not be clinically significant, with acceptable survival rates observed in the high risk group. There were no significant differences in stroke rate and acute rejection, although there was an observed difference in dialysis events. Given the acceptable overall outcomes in the higher BMI cohort, the benefits of heart transplantation in this group may outweigh the risks, and these patients should be considered as candidates for heart transplantation.