Abstract
OBJECTIVE: This exploratory study examined the relationship between oxygen delivery index (DO2i) during DCD heart transplant (HT), warm ischemic time, and posttransplant outcomes. METHODS: All DCD HT between 10/2021 and 12/2024 using normothermic regional perfusion (NRP) at our institution were included. Multiorgan transplants and congenital heart disease patients were excluded. Critical areas-sum of magnitude and duration of DO2i under specific thresholds-were calculated for thresholds 300, 280, and 260 mL/min/m2. Receiver operating characteristics (ROC) analysis dichotomized the critical area into high area (low DO2i) and low area (high DO2i) groups. Patients were then stratified into 4 groups based on high/low functional warm ischemic time (FWIT), and high/low DO2i. Outcomes were compared across groups. RESULTS: The critical area under 260 mL/min/m2 was the best predictor of severe primary graft dysfunction (PGD). 102 patients met inclusion criteria, and were stratified into four groups based on FWIT above/below 23 min and critical area below/above 1,424 mL/m2 (identified by ROC analysis). 39 (38.2%) patients had low FWIT/ high DO2i, 18 (17.6%) had low FWIT/ low DO2i, 24 (23.5%) had high FWIT/high DO2i, and 21 (20.6%) had high FWIT/low DO2i. Rates of severe PGD were greater in the high FWIT/low DO2i group compared to the low FWIT/high DO2i group (23.8% vs. 0%, p = 0.004). Rates of 30-day mortality were higher in the high FWIT/low DO2i group compared to the low FWIT/high DO2i group (14.3% vs. 0%, p = 0.039). CONCLUSIONS: Higher oxygen delivery during HT was associated with improved short-term outcomes, and may counteract the myocardial damage from warm ischemia during DCD.