Dynamic associations between adverse events after lung transplantation and allograft ischaemic time.

Abstract

The effect of allograft ischaemic time (AIT) on postoperative events after lung transplantation (LTx) remains unclear. This study aims to assess the feasibility of extending the duration of AIT. The United Network for Organ Sharing database was queried for adult LTx from 4 May 2005 to 30 June 2020. Patients were divided as per AIT into standard (SIT, <6 hours) and prolonged (PIT, ≥6 hours) groups using propensity score matching and evaluated on a continuous scale using restricted cubic splines. The primary outcome was overall 1-year and 5-year survival. Among 11,438 propensity matched recipients, SIT and PIT showed no differences in overall 1-year (P = 0.29) or 5-year (P = 0.29) survival. PIT independently predicted early postoperative ventilator support for >48 hours (OR = 1.33, 95% CI : 1.22-1.44), dialysis (OR = 1.55, 95% CI : 1.30-1.84), primary graft dysfunction (PGD; OR = 1.28, 95% CI : 1.09-1.50), and acute rejection (AR; OR = 1.42, 95% CI : 1.24-1.62), and interestingly, decreased 5-year bronchiolitis obliterans syndrome (BOS; HR = 0.91, 95% CI : 0.85-0.97). In relative risk curves, 1-year mortality, prolonged ventilation, dialysis, and PGD steadily increased per hour as AIT extended. The risk of AR and 5-year BOS also showed significant changes between 5 and 8 hours of AIT. In contrast, 5-year mortality remained constant despite rising AIT. Prolonged AIT worsened early outcomes such as PGD, but improved BOS freedom at later timepoints. Despite this, both short- and long-term survival were similar between PIT and SIT patients. Dynamic risk changes in post-transplant events should be noted for prolonged ischaemia lung use.