(156) Weighty Matters: Obesity and Survival in Heart Transplant Recipients Bridged With Short-Term MCS

Introduction: Obesity is a significant risk factor for various cardiovascular diseases and can impact heart transplant outcomes. While obesity may negatively affect post-transplant outcomes, its specific impact on mortality in patients bridged to transplant with short term mechanical circulatory support (STMCS) is not known. This study examined the association between obesity and mortality in this population.

Methods: We conducted a retrospective cohort study including heart transplant recipients who received STMCS pre-transplant. Demographics, STMCS type used including extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump (IABP), and Impella, and post-transplant outcomes were extracted from electronic medical records. Obesity was defined as body mass index (BMI)≥30 kg/m² and transplantation death as patient death any time after transplant. Cox proportional hazards models assessed the association between obesity and mortality after adjusting for potential confounders.

Results: Among 221 heart transplant recipients who received STMCS, with a mean age of 52.85±12.48 years, 72 (32.6%) were obese. Of these, 52 (30.1%) were obese. Post-transplantation mortality was 19 (8.6%), with 7 deaths (3.2%) in the obese group and 12 (5.4%) in the non-obese group. Males had higher mortality compared to females in both obese (5 males, 9.62% vs. 2 females, 10%) and non-obese groups (10 males, 8.26% vs. 2 females, 7.14%). Over a median follow-up of 1.11 years, mortality rates were comparable between obese and non-obese recipients (adjusted hazard ratio 0.913 [0.345-2.417], p=0.855). Subgroup analyses by STMCS type showed consistent trends in mortality (p>0.05) with 42 (58.3%) obese patients under Impella, 20 (27.8%) under ECMO, and 20 (27.8%) under IABP.

Conclusions: This study found no significant difference in post-transplant mortality between obese and non-obese heart transplant recipients who used STMCS pre-transplant. These results suggest that obesity alone may not significantly impact post-transplant survival in this cohort.