Ethicality of Heart Transplantation from Donation after Circulatory Death Donors

Abstract

rd of transplants performed in the United Kingdom are now undertaken using organs obtained from DCD donors [1]. Historically, the transplantation of organs procured after cardiac arrest was instrumental in pioneering transplantation. The initial heart and liver transplants were performed using organs removed after death of the donor [2,3]. Prior to definition of criteria for brainstem death (BSD), cardiac arrest and loss of circulation were considered essential for confirmation of donor death. The practice of DCD organ donation has raised many ethical concerns and continues to have detractors. Loss of cardiac output and cessation of circulation are the principal requirements for certification of death in the DCD donor. The ethicality of resuscitating the heart in DCD donors has been questioned. It is suggested by some that “cardiac death” should be an irreversible occurrence. Once established it is argued that resuscitation of the heart by any means would potentially negate the diagnosis of death due to recovery of heart beat and restoration of circulation within the donor. The terminal event that precedes the decision to withdraw therapy in the majority of DCD donors is usually severe neurological injury. However, neurologic testing in these donors does not identify irreversible loss of brain-stem function. Consequently, conventional heart-beating cadaveric donation is not an option. The lack of a clear definition of death contributes towards further confusion. In a recent clinical case of human DCD heart resuscitation, we utilized an extracorporeal perfusion circuit to deliver oxygenated blood to the donor after circulatory arrest [4]. The commonest protocol for DCD organ procurement relies on the rapid infusion of cold preservation solution into the donor circulation with the aim of initiating organ protection and preservation through cooling of organs. More recently, the use of extracorporeal membrane oxygenation (ECMO to reperfuse the donor with normothermic oxygenated blood has also been undertaken on the basis that warm blood perfusion may be a physiologically more appropriate means for organ resuscitation and preservation [5,6]. Currently, this practice is limited to the procurement of the kidneys and liver. The majority of retrieval teams who undertake ECMO reperfusion of the DCD donor have achieved this through cannulation of peripheral vessels, most commonly the femoral artery and vein. Institution of ECMO leads to retrograde perfusion of the abdominal viscera. During the early experience with ECMO in DCD donors, cardiac resuscitation was observed upon reperfusion. As this was deemed unnecessary, specific measures were undertaken to depress cardiac activity including the establishment of systemic hyperkalemia to produce cardiac arrest. The deployment and inflation of intra-aortic balloon catheters for occlusion of the descending aorta was another means of preventing coronary reperfusion, whilst maintaining perfusion of transplantable abdominal organs [7,8]. There remain several important ethical issues relating to DCD heart resuscitation which require discussion and debate: 1.� The appropriateness of restoration of circulation and recovery of heart beat within the donor for purposes of organ resuscitation and evaluation of function 2.� The ethicality of pre-treatment of the donor prior to withdrawal of support to facilitate the organ retrieval and procurement process (i.e. systemic heparinization, insertion of vascular catheters for delivery of preservation solutions)