Donor age and ischemic time in heart transplantation – implications for organ preservation

Background: The Organ Care System and Non-ischemic Heart Preservation methods have emerged as significant advancements in heart transplantation, designed to mitigate ischemic injury and extend preservation times. However, their high costs and logistical complexities necessitate strategic utilization. Methods: We evaluated data from 83,761 heart transplants registered in the International Society for Heart and Lung Transplantation registry from 1988 to 2018. Utilizing a Cox proportional hazards model, we explored the influence of donor age and ischemic time on transplant survival. A key innovation of our study is the development of a nomogram to predict post-transplant survival, incorporating both traditional and advanced statistical methods. Results: The median age of recipients was 52 years (22% female) and 33 years (31% female) for donors. Analysis revealed a median ischemic time of 3 hours and median survival of 11.5 years across the cohort. The nomogram showed a decline in survival probabilities with increasing donor age, notably from age 40 and more significantly with ischemic times >4 hours. Ischemic times ≥4 hours versus <2 hours were associated with hazard ratio (HR) of 1.2 (95% CI, 1.1–1.3) for donors aged 40–59, a disparity that escalated for donors aged ≥60 (HR: 2.0; 95% CI, 1.5–2.7). Conclusions: This study highlights the importance of careful donor selection and indicates that certain groups, particularly older donors with prolonged ischemic times, might benefit from ex-vivo preservation techniques. The developed nomogram offers a practical tool for clinicians, enhancing decision-making by providing detailed insights into the relationship between donor age, ischemic time, and post-transplant mortality.