Distinct goal-directed perfusion signatures in donation after brain death versus circulatory death heart transplantation.

BACKGROUND

Continuous oxygen extraction ratio (O2ER) monitoring during cardiopulmonary bypass is an emerging strategy to support goal-directed perfusion (GDP) during heart transplantation (HT). Because donation after circulatory death (DCD) introduces additional warm ischemia, we examined whether post-reperfusion O2ER dynamics differ from donation after brain death (DBD).

METHODS

Adult HT at a single center (10/2021-06/2025) with continuous perfusion data were retrospectively reviewed. O2ER was calculated as oxygen consumption/oxygen delivery index (DO2i). The primary endpoint was O2ER after graft reperfusion (cross-clamp removal), quantified as the area above O2ER of 0.25. Weighted regression after adjusting for baseline characteristics identified the association of DCD status, pre-reperfusion O2ER, and post-reperfusion DO2i on post-reperfusion O2ER.

RESULTS

Among 322 HT, 193 (59.9%) were DBD and 129 (40.1%) were DCD. Pre-reperfusion DO2i and O2ER, and post-reperfusion O2ER were similar between DBD and DCD cohorts. Weighted regression analysis demonstrated that DCD donor status (mean difference 0.36, 95% CI 0.11-0.60), pre-reperfusion area above O2ER 0.25 (mean difference 0.39, 95% CI 0.29-0.50), and post-reperfusion time below DO2i 280 mL/min/m² (mean difference 0.05, 95% CI 0.03-0.07) were all independently associated with post-reperfusion area above O2ER 0.25. The interaction term between DCD donor status and pre-reperfusion O2ER was also significantly associated with post-reperfusion O2ER (mean difference -0.27, 95% -0.41 - -0.14).

CONCLUSIONS

DCD grafts exhibit persistently higher O2ER profiles and reduced metabolic responsiveness to pre-reperfusion optimization. These findings underscore the need for individualized, real-time O2ER-guided GDP to dynamically match perfusion to graft and patient-specific metabolic demands.