Oversizing lung allografts deteriorates outcomes in patients with pulmonary fibrosis

Background Lung transplantation is the only curative treatment for patients with end-stage pulmonary fibrosis. Due to the shortage of donor organs most lung allografts are either oversized or undersized. It is still under debate whether over- or undersizing is preferably performed regarding the postoperative outcome. We therefore analysed our data using predicted total lung capacity to compare size-mismatches. Methods Patient records were retrospectively reviewed. Three groups were formed, one including patients with a donor-recipients pTLC-ratio (DRPR) of <1.0 (undersized group), the second with a DRPR of ≥1.0 and <1.1 (size matched group) and the third group with a DRPR of ≥1.1 (oversized group). Outcomes were evaluated using Chi-Square test and Kruskall-Wallis test as well as Kaplan-Meier analysis, competing risk analysis and multivariable analysis, respectively. Results Between January 2010 and May 2023, among the 1501 patients transplanted at our institution, 422 (28%) patients were included, 26 (2%) patients forming the oversized group (median DRPR: 1.14), 101 (7%) patients forming the size matched group (median DRPR: 1.03) and 296 (20%) patients forming the undersized group (median DRPR: 0.92). Patients from the oversized group had a higher PGD grade 3 rate at 24 (p<0.001), 48 (p<0.001) and 72 (p=0.039) hours after transplantation as well as a higher in-hospital mortality compared to the undersized group (p=0.033). The long-term survival was also better in the undersized group compared to the oversized group (p=0.011) and to the size matched group (p=0.01). Conclusion Oversizing lung allografts more than 10% deteriorated early postoperative outcomes and long-term survival in patients with pulmonary fibrosis.