Association of Cold Ischemic Time with Early and Long-Term Outcomes in a Nationwide Korean Heart Transplant Cohort.

Background

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Objectives

Cold ischemic time (CIT) is considered a determinant of graft dysfunction after heart transplantation (HT), but its impact within typical Korean preservation times remains unclear. We evaluated the associations of CIT and warm ischemic time (WIT) with outcomes in a Korean cohort.

Methods

We analyzed 989 adults undergoing isolated HT in the Korean Organ Transplant Registry from 2014 to 2023. Recipients were grouped by CIT (≤60, 61-120, 121-180, and >180 minutes). The primary endpoint was postoperative extracorporeal membrane oxygenation (ECMO) requirement, and the secondary endpoint was 30-day mortality. Long-term survival was assessed using Kaplan-Meier and multivariable Cox regression. Restricted cubic spline analyses and a prespecified WIT <60-minute subgroup analysis were performed.

Results

Postoperative ECMO occurred in 14.9%, and 30-day mortality in 4.8%. Neither endpoint increased across CIT categories, and spline analyses showed no significant nonlinearity. After adjustment, CIT was not associated with 30-day mortality (per 10 minutes, adjusted odds ratio [aOR], 1.03; 95% confidence interval [CI], 0.98-1.08). In contrast, WIT was associated with postoperative ECMO (aOR, 1.12; 95% CI, 1.05-1.20) and 30-day mortality (aOR, 1.17; 95% CI, 1.06-1.29). Preoperative ECMO was associated with postoperative ECMO (aOR, 3.93; 95% CI, 2.69-5.74). Long-term survival was similar across CIT groups. The prespecified WIT <60-minute subgroup showed consistent findings for early outcomes.

Conclusions

In this Korean HT cohort, CIT within the observed range was not associated with early or long-term outcomes. Recipient severity and implantation-related ischemic burden appeared more influential than moderate differences in CIT.