Ex Situ Perfusion with Histidine-Tryptophan-Ketoglutarate-N Improves Myocardial Microvascular Circulation and Diastolic Dysfunction of Porcine Donor Hearts

Background: An impaired coronary microvascular circulation in cardiac allografts is associated with diastolic dysfunction, graft failure, and death after heart transplantation. Ischemia/reperfusion (IR) injury impairs contractility and coronary microvascular circulation. Ex situ blood perfusion (ESBP) is a novel method for donor heart maintenance, reducing the time of cold ischemia. Nevertheless, ESBP adds another reperfusion period to the donor heart. The novel histidine-tryptophan-ketoglutarate (HTK)-N solution has been developed to improve myocardial contractility and vascular function of donor hearts. The impact of ex situ perfusion with oxygenated HTK-N solution on coronary microvascular circulation and diastolic function has not been investigated yet.