Utilization, Trends, and the Impact of Donor Age Over 50 on Heart Transplant Outcomes

K. Ohlrich¹, K. Sokevitz², K. Shorbaji¹, B. Welch³, A. Kilic^4
1Medical University of South Carolina, Mount Pleasant, South Carolina ²Medical University of South Carolina, Mt. Pleasant, South Carolina ³Medical University of South Carolina (MUSC), Mount Pleasant, South Carolina ⁴MUSC, Charleston, South Carolina

Purpose: Donor age is an important consideration in the heart transplantation (HT) selection process. In the climate of new technologies facilitating use of higher risk organs and the 2018 allocation policy change, this study aimed to investigate utilization, trends, and HT recipient outcomes using donors over 50 years old.

Methods: The United Network for Organ Sharing (UNOS) database was utilized to identify adult HT recipients between January 2010 and December 2022. Recipients were categorized into two groups based on donor’s age; >50 years old and ≤50 years old). The Mann-Kendall trend test was utilized to ascertain the statistical significance of the trend in transplants using donors>50 years old over the study period. Kaplan-Meier analysis was used to estimate survival probability of recipients from donors aged>50 years at 30-days, 1-year, and 5-years. Multivariable Cox regression models were built to measure the effect of the donor’s age on HT recipient mortality at these time intervals, as well as sub analyses looking at risk factors specific to outcomes within the donors>50 years group only.

Results: Of 31,139 recipients from 149 centers that were included in the study, there were 2,082 (6.8%) recipients from donors>50 years old. The proportion of recipients from donors>50 years old decreased from 8% in 2010 to 4.1% in 2022 (p=0.012). There were 128 centers that utilized donors>50 years old before and after the 2018 allocation policy change. Within these centers, the percentage of donors>50 years old relative to center overall HT volume decreased by a mean of 17.97% after the policy change (Figure 1). 14.0% of centers had increased utilization (>5% change) of these donors, while 57.8% had minor (within 5% increase or decrease), and 28.2% had a >5% decrease. There was increased recipient risk-adjusted mortality after HT in cases using donors>50 years: 1.26 (1.01-1.56, p=0.036) at 30 days, 1.37 (1.20-1.57, p< 0.001) at 1 year, and 1.28 (1.15-1.42, p< 0.001) at 5 years. Recipients from donors>50 years had higher rates of postoperative acute renal failure requiring dialysis (14.6% vs 11.9%, p=0.001), and permanent pacemaker implantation (4.0% vs 2.3%, p< 0.001). In sub-analysis of donors>50 years, increased 30-day, 1-year, and 5-year recipient mortality was observed with donor Hispanic race, increased recipient creatinine and bilirubin, and preoperative mechanical ventilation or durable VAD (ventricular assist device).

Conclusion: Despite technologies aimed to increase utilization of higher risk donors, trends demonstrate decreased use of older donors. Donors aged over 50 remain a risk factor for poorer outcomes, particularly in recipients with pre-transplant end-organ dysfunction or durable VAD, and reevaluation with increased utilization of ex vivo technologies will be prudent.

Identify the source of the funding for this research project: There was no dedicated funding for this project.