Cold Ischemia Time Is an Important Risk Factor for Prolonged Length of Stay Post-Lung Transplantation.

PURPOSE: In lung transplantation (LTx), optimal cold ischemia time (CIT) is considered <6 h, but is often extended to maximize allograft utilization. Given the limited analysis of how variation in CIT impacts outcomes, we examined its correlation with graft survival, patient mortality, and prolonged length of stay (PLOS), defined as ≥30 days. METHODS: Using the United Network for Organ Sharing database, we retrospectively analyzed 39 806 adult LTx between May 4, 2005, and December 1, 2025. Ex-vivo lung perfusion (EVLP) cases (n = 1378) were isolated for separate analysis. The remaining 39 161 were categorized into hourly CIT increments. We conducted univariate and multivariate analyses with three outcomes of interest: PLOS, graft survival, and patient mortality. RESULTS: CIT correlated more strongly with PLOS than graft survival or patient mortality. CIT <5 h was protective against PLOS, while >6 h increased risk. A steady and significant increase in odds of PLOS with increasing CIT was observed, with risks lowest at 3-4 h (odds ratio [OR], 0.829; 95% confidence interval [CI], 0.755-0.911) and highest at 11-12 h (OR, 2.02; 95%CI, 1.61-2.54). Isolated EVLP analysis showed no such significant correlation. CONCLUSION: Nearly every hour increases in CIT showed a significant impact on odds of PLOS after LTx. Minimizing CIT is critical to reduce posttransplant PLOS and associated healthcare costs. Novel methods of preservation may be key to mitigate this risk.