The Impact of Whole Blood versus Dilute Whole Blood on Coronary Vascular Tone during Ex Situ Heart Perfusion

Purpose Ex situ heart perfusion (ESHP) allows continuous functional and metabolic assessment of donor hearts before transplantation. Evidence indicates that circulating chemical mediators in whole blood are involved in the regulation of oxygen delivery. We aim to evaluate the impact of whole blood versus dilute whole blood in the regulation of coronary vascular tone during ESHP. Methods Normal porcine hearts were perfused in working mode for 6 hours either by whole blood (n=5) or whole blood with Krebs-Henseleit solution (1:1) containing 8% albumin (n=5). Cardiac functional parameters, coronary artery flow and metabolism were monitored continuously. Coronary vascular resistance (CVR) was calculated to evaluate coronary artery function. These parameters were compared between groups at different time. Results The whole blood group had significantly higher hemoglobin concentration than blood+buffer group (p Conclusion Whole blood appears to play a role in regulating coronary vascular tone, as indicated by relative higher vascular resistance and better oxygen delivery in whole blood perfusion after 6 hours. The relative contribution of hemoglobin content versus plasma protein content is not clear. Whether this translates into improved post-transplant function remains to be determined.