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

The effect of allograft ischaemic time (AIT) on postoperative events after lung transplantation 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 lung transplantation from 4 May 2005 to 30 June 2020. Patients were divided as per AIT into standard ischaemic time (<6 h) and prolonged ischaemic time (≥6 h) 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, standard ischaemic time and prolonged ischaemic time showed no differences in overall 1-year (P = 0.29) or 5-year (P = 0.29) survival. Prolonged ischaemic time independently predicted early postoperative ventilator support for >48 h (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), acute rejection (OR = 1.42, 95% CI 1.24-1.62), and interestingly, decreased 5-year bronchiolitis obliterans syndrome (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 acute rejection and 5-year bronchiolitis obliterans syndrome also showed significant changes between 5 and 8 h of AIT. In contrast, 5-year mortality remained constant despite rising AIT.

Prolonged AIT worsened early outcomes such as PGD, but improved bronchiolitis obliterans syndrome freedom at later time points. Despite this, both short- and long-term survival were similar between prolonged ischaemic time and standard ischaemic time patients. Dynamic risk changes in post-transplant events should be noted for prolonged ischaemia lung use.