Lactate during ex-situ heart perfusion does not predict the requirement for mechanical circulatory support following donation after circulatory death (DCD) heart transplants.

BACKGROUND: Ex-situ heart perfusion (ESHP) is commonly used for the reanimation and preservation of hearts following donation after circulatory determined death (DCD). The only commercially available existing ESHP device promotes perfusate lactate levels for assessment of heart viability. The reliability of this marker is yet to be confirmed for DCD heart transplantation. METHODS: This is a single center, retrospective study examining DCD heart transplants from March 1, 2015 to June 30, 2020. Recipients were divided into 2 groups dependent upon their requirement for or absence of mechanical circulatory support post-transplant. Lactate profiles obtained during ESHP were analyzed. Hearts were procured using the direct procurement and perfusion (DPP) method. RESULTS: Fifty-one DCD heart transplant recipients were studied, of which 20 (39%) were dependent on mechanical circulatory support (MCS) following transplantation, (2% Ventricular Assist Device (VAD), 16% Extra Corporeal Membrane Oxygenation (ECMO) and 21% Intra-aortic balloon pumps (IABP). There was no difference in arterial lactate profiles on ESHP at any time point for those dependent upon MCS support (MCS) and those that were not (no MCS) post-transplant. After 3 hours of ESHP, the arterial lactate was >5mmol/L in 80% upon MCS vs 62% no MCS, p = .30. There was also no difference in ESHP rising arterial lactate concentrations, (15% MCS vs 13% non MCS, p = 1.00). CONCLUSION: For DCD hearts transplants retrieved using the DPP technique, lactate profiles do not seem to be a reliable predictor of mechanical circulatory support requirement post-transplant.