Cold ischemia >4 hours increases heart transplantation mortality. An analysis of the Spanish heart transplantation registry

Background: Cold ischemia time (CIT) has been associated to heart transplantation (HT) prognosis. However, there is still uncertainty regarding the CIT cutoff value that might have relevant clinical implications. Methods: We analyzed all adults that received a first HT during the period 2008–2018. CIT was defined as the time between the cross-clamp of the donor aorta and the reperfusion of the heart. Primary outcome was 1-month mortality. Results: We included 2629 patients, mean age was 53.3 ± 12.1 years and 655 (24.9%) were female. Mean CIT was 202 ± 67 min (minimum 20 min, maximum 600 min). One-month mortality per CIT quartile was 9, 12, 13, and 19%. One-year mortality per CIT quartile was 16, 19, 21, and 28%. CIT was an independent predictor of 1-month mortality, but only in the last quartile of CIT >246 min (odds ratio 2.1, 95% confidence interval 1.49–3.08, p < .001). We found no relevant differences in CIT during the study period. However, the impact of CIT in 1-month and 1-year mortality decreased with time (p value for the distribution of ischemic time by year 0.01), particularly during the last 5 years. Conclusions: Although the impact of CIT in HT prognosis seems to be decreasing in the last years, CIT in the last quartile (>246 min) is associated with 1-month and 1-year mortality. Our findings suggest the need to limit HT with CIT > 246 min or to use different myocardial preservation systems if the expected CIT is >4 h