Association of Predicted Heart Mass from Mesa and Left Ventricular Mass from Dallas Heart Study with Heart Transplant Outcomes in the New Allocation System

Abstract

<h3>Purpose</h3> Donor and recipient size matching remains an important component of donor selection in heart transplant (HT). One approach to size matching includes using predicted heart mass (PHM), derived from the Multi-ethnic Study of Atherosclerosis (MESA). Compared to MESA, the Dallas Heart Study (DHS) may better represent the U.S. donor pool. We examined the association of PHM from MESA and predicted left ventricular mass (PLVM) from DHS with HT outcomes in two eras. <h3>Methods</h3> Linear regression was used to model PLVM from DHS participants (n=1,746) with normal LV size and function on cardiac MRI and BMI < 35 kg/m². The DHS PLVM model included age, gender, height, weight and race. We then examined the association of DHS PLVM and MESA PHM with 1-year mortality post-HT in the United Network of Organ Sharing registry (Era 1: 2007-2016 and Era 2: 2018-2021) using Kaplan-Meier survival estimation and univariate Cox proportional hazards models stratified by presence or absence of low donor:recipient mass ratio (< 0.86). <h3>Results</h3> The DHS derivation cohort had a median age of 43 years, 40% self-identified as Black and 18% as Hispanic, 23% had HTN and 7% had DM. DHS PLVM and MESA PHM were significantly correlated (R=0.96, p < 0.001). There was no statistically significant difference in the distribution of donor-recipient mass ratios by DHS PLVM and MESA PHM across eras (Figure). In Era 1, a low DHS PLVM ratio was associated with worse 1-year mortality post-HT (p < 0.001), similar to the previously reported association with MESA PHM). However, in Era 2 neither DHS PLVM nor MESA PHM were associated with 1-year mortality [PLVM HR 0.9 (0.7-1.2) and PHM HR 1.1 (0.8-1.4)] (Figure). <h3>Conclusion</h3> In a contemporary cohort of HT recipients, neither PHM nor PLVM from DHS were associated with 1-year mortality post-HT. Additional donor and recipient factors such as mechanical circulatory support may be playing a larger role in HT outcomes in the current era.