Effect of Older Donors (Age ≥40) and Normothermic Regional Perfusion on DCD Heart Transplant Outcomes

Older donors have traditionally been avoided in heart transplantation, particularly in donation after circulatory death (DCD) transplants. However, outcomes of older DCD organs remains unknown. This study examines the effects of donor age on DCD heart transplant outcomes and the potential impact of normothermic regional perfusion (NRP).

The United Network for Organ Sharing (UNOS) database was queried for adult DCD heart transplants from 12/1/2019 to 6/30/2023. Loss to follow-up, multiorgan and prior heart transplants were excluded. Primary outcome was overall survival. Secondary outcomes were acute rejection, 30-day and 1-year mortality. Subgroup analysis was performed for non-NRP and NRP transplants.

The study included 842 DCD heart transplants: 720 from donors <40 years and 122 from donors ≥40 years. The use of organs from donors ≥40 years increased over time, from 0 in 2019 to 59 transplants in 2023. Compared to donors <40, older donors had significantly higher rates of smoking history (23.5% vs 6.6%, p < 0.001), diabetes (6.7% vs 1.8%, p = 0.004), and hypertension (34.5% vs 9.0%, p < 0.001).There was no difference in perioperative outcomes including length of stay, acute rejection, 30-day, 6-month or 1-year mortality rates. Donor age ≥40 did not significantly affect survival on univariable or multivariable Cox regression (HR 0.93, 95% CI 0.46-1.88, p = 0.835) and survival analysis. When stratified by procurement technique, NRP was associated with significantly lower 6-month mortality (0.0% vs 8.3% in ≥40 donors; 2.3% vs 6.8% in <40 donors; overall p = 0.004) and 1-year mortality (1.4% vs 8.3% in ≥40 donors; 3.8% vs 7.7% in <40 donors; overall p = 0.042). In multivariable analysis, the combination of older donor age with NRP showed a trend toward lower hazard ratio (HR 0.45, 95% CI 0.11-1.95) compared to younger donors without NRP, though this did not reach statistical significance (p = 0.287).

Both early outcomes and overall survival are not significantly affected by donor age in DCD heart transplantation. However, when stratified by procurement technique, NRP was associated with significantly lower 6-month and 1-year mortality, though these benefits did not translate to significant differences in overall survival. The use of older donors may safely expand the DCD donor pool, particularly when NRP is employed, though longer-term follow-up is required to confirm these findings.