Plasma-supplemented red cell concentrates as alternatives to whole blood in porcine ex vivo heart perfusion

BACKGROUND: Normothermic ex vivo organ perfusion holds promise for increasing the organ donor pool; however, standard use of autologous whole blood (WB) presents logistical and functional challenges. This study compared red cell concentrate (RCC)-, rejuvenated RCC-, and WB-based perfusates over a 4-hour ex vivo heart perfusion (EVHP) to assess blood quality and its impact on myocardial function. METHODS: Porcine WB was leukodepleted and hypothermically stored until perfusion. RCCs were divided into five perfusate groups (n = 3, unless otherwise indicated): (A) WB with 14-day-stored RCCs (n = 2), (B) 14-day-stored RCCs alone, (C) 14-day-stored RCCs with plasma, (D) day-14 rejuvenated RCCs, perfused on day 14 of storage with plasma, (E) day-14 rejuvenated RCCs, perfused on day 21 of storage with plasma. All groups were compared to WB (n = 5). At the start and after four hours of perfusion, measurements of coronary flow, cardiac index, oxygen extraction, oxygen consumption, metabolites, red blood cell (RBC) indices, hemolysis, extracellular potassium, methemoglobin, p50, morphology, osmotic fragility, and deformability were collected. RESULTS: Plasma-containing perfusates showed increased coronary flow, cardiac index, and initial oxygen consumption. After four hours, glucose concentrations in RCC-based solutions decreased, while hemolysis increased in most groups. Both rejuvenated RCC groups had lower extracellular potassium concentrations and improved oxygen affinity. WB-based perfusates demonstrated better RBC deformability and reduced fragility. CONCLUSIONS: Plasma is crucial for maintaining perfusate and myocardial quality in porcine EVHP models. RCC-based perfusates alongside plasma offer comparable quality to WB, potentially addressing some of the logistical challenges faced by EVHP, though this remains to be translated to humans.