Total ventricular mass oversizing +50% or greater was a predictor of worse 1-year survival after heart transplantation

Objectives: Current donor-recipient size matching guidelines rely primarily on body weight, with no specified oversizing cutoff values. Recent literature has explored predicted total ventricular mass matching over body weight matching. We aim to explore the impact of total ventricular mass oversizing on heart transplant outcomes.

Methods: The United Network for Organ Sharing database was queried for adults who underwent primary heart transplant from 1997 to 2017. By using validated equations, donor-recipient total ventricular mass mismatch was calculated. Donor-recipient pairs were divided into 3 groups by total ventricular mass mismatch. Post-heart transplant 1-year survival was analyzed using the Kaplan-Meier method and Cox proportional hazards models. We also investigated post-heart transplant complications, independent predictors for mortality, donor-recipient sex mismatch, and donor-recipient body habitus in total ventricular mass mismatch greater than +50%.

Results: A total of 34,455 donor-recipient pairs were included. Fractional polynomial regression demonstrated increased the risk of mortality with higher total ventricular mass mismatch. Total ventricular mass mismatch of +48.3% maximized the Youden Index. Donor-recipient pairs were subsequently grouped by total ventricular mass mismatch as -20% to +30%, +30% to +50%, and greater than +50%. Total ventricular mass mismatch greater than +50% was an independent risk factor for 1-year mortality (hazard ratio, 1.40, P = .004) and was associated with increased postoperative stroke (P = .002). Some 80.3% of these recipients were smaller female patients with male donors. Total ventricular mass mismatch from +30% to +50% was not associated with worse survival (P = .17).

Conclusions: Total ventricular mass mismatch greater than +50% is associated with worse 1-year survival, although this group comprises a small portion of heart transplant. total ventricular mass mismatch from +30% to +50% is not associated with worse survival. These outcomes should be considered in selecting donors and in efforts to expand the potential donor pool.