Influence of Donor-Recipient Age Mismatch in Young Lung Transplant Recipients

Purpose Lack of organ donors demands transplantation of older lungs into younger recipients. Providing that other general organ donor selection criteria are fulfilled; it still remains questionable whether high age mismatch negatively affects short- and long-term outcomes. Here we investigate outcomes of lung recipients aged between 0 and 50 years whose donors had a high or low age mismatch compared to their respective recipients. Methods Records of patients aged between 0 and 50 years (33±12 years) and transplanted between 2005 and 2020 were retrospectively reviewed. Two groups were formed, one including recipients who received organs from donors at least 20 years older (high-mismatch group) and the other group including recipients whose donors were not older than 10 years (low-mismatch group) compared to their corresponding recipients. Donor smoking status, pO2-pressure and ventilation time (days) were evaluated. Incidence of Primary Graft Dysfunction grade 3 (PGD 3), ICU stay, ventilation time, perioperative hospital stay, chronic lung allograft dysfunction (CLAD) and graft survival were compared using Chi-Square test, Mann-Whitney-U test and Kaplan-Meier analysis, respectively. Results During the study period, among the 1722 patients transplanted at our institution, 172 (9.9 %) patients form the high-mismatch group and 212 (12.3%) patients the low mismatch group. Prevalence of donor smoking history was higher in low-mismatch recipients (34% vs. 46%; p=0.024). PO2-pressure (390 vs. 405 mmHg; p=0.39) and median ventilation time (4 vs. 4 days; p=0.898) prior organ procurement did not differ between groups. Incidence of PGD Grade 3 after 48 (11% vs. 6%; p=0.078) and 72 (11% vs. 6%; p=0.078) hours was not significantly different. Median mechanical ventilation (14 vs. 14 hours; p=0.76), ICU stay (4 vs. 4 days; p=0.6) and postoperative hospital stay times (25 vs. 24 days; p=0.17) did not differ between groups. At 5- and 10-year follow-up, overall graft survival (66.3% vs. 67.3%, 54% vs. 48%, p=0.956), patient survival conditioned to hospital discharge (75.7% vs. 79.2%, 62.9% vs. 64.1%, p=0.541) and freedom from CLAD (57.6% vs. 62.9%, 47% vs. 38%, p=0.944) was comparable between the groups. Conclusion Age mismatch alone is not a limiting factor for accepting donor lungs. Long term survival and incidence of CLAD are not affected providing general donor organ selection criteria are considered.