Is it Time to Include Post-Transplant Survival in Heart Transplantation Allocation Rules?

Abstract

Identifying an efficient and fair allocation of limited donated hearts to patients on the waiting list is one of the top priorities in heart transplantation management. The recent heart allocation rule by the United Network for Organ Sharing has emphasized medical urgency to address the heart transplant crisis by further dividing the previous sickest patient group into three subgroups. However, there is a significant debate on optimality and fairness of such policy.We undertake a rigorous study to address this debate. In particular, we show that the optimal policy of the fluid model with a set of fairness constraints is a state-dependent priority rule, and provide insight on the impact of fairness constraints on such priorities. We quantify the price that the society pays for following a medical urgency approach, which favors the sickest patients, compared to a utilitarian approach, which seeks to maximize total life years. Our results, produced by a validated simulation model, reveal that the said price is 8% of total life years and increases to 10% by considering a broader regional sharing aligned with four hour cold-ischemic time for heart. In fact, we provide concrete numbers for pre-transplant death and life years broken down for each health and age group to further shed light on this debate. We also consider relevant objectives in transplantation and our results show that the optimized utilitarian policy outperforms that of the medical urgency one in other measures. Our analysis provides novel insights on optimal patient allocation and sheds light on the debate around this challenging problem.