Predicted Heart Mass and Outcomes in the Contemporary Era of Heart Transplantation: Insights from the Dallas Heart Study

Background

Donor-recipient size matching is a key factor in donor selection for heart transplantation (HT). One approach uses predicted heart mass (PHM), derived from the Multi-Ethnic Study of Atherosclerosis (MESA). We sought to examine whether predicted left ventricular mass (PLVM) derived from the Dallas Heart Study (DHS) is associated with post-transplant outcomes.

Methods

The study cohort included participants without pre-existing cardiac disease in the DHS who had cardiac MRIs (n = 1746). A PLVM model was derived by linear regression. The DHS PLVM and MESA PHM were tested for correlation. The associations of the DHS PLVM and the MESA PHM with 1-year mortality post-HT were assessed in the United Network for Organ Sharing Registry in 3 eras: era 1: 1/1/2011–12/31/2014; era 2: 1/1/2015–10/17/2018; and era 3: 10/18/2018–12/31/2021). A pre-specified threshold for low donor-to-recipient mass ratio (< 0.86) was used in Kaplan-Meier survival estimation and univariate and multivariable Cox proportional hazard models.

Results

The DHS cohort had a median age of 43 (IQR 36–52) years, 49% male, 40% Black, and 18% Hispanic ethnicity. The DHS PLVM was highly correlated with the MESA PHM: r = 0.96; P < 0.001. In era 1, a low donor-to-recipient mass ratio according to the DHS PLVM was associated with increased 1-year mortality rates (log-rank P < 0.001) as was the MESA PHM (log rank P = 0.002). However, in eras 2 and 3, a low donor-to-recipient mass ratio by either the DHS PLVM or MESA PHM was not associated with increased 1-year mortality rates.

Conclusion

PLVM was highly correlated with PHM. A low donor-to-recipient mass ratio, whether assessed by PLVM or PHM, was associated with 1-year mortality post-HT in a historical era but not in the current era under the new allocation system. These findings suggest that other factors may be contributing to donor selection and mortality risk in the modern era.