Using livers from donation after cardiac death donors—A proposal to protect the true Achilles heel

Abstract

As the waiting list for organ transplant continues to increase (over 90,000 candidates as of May 30, 2007), the pressure to increase the number of donor organs is the impetus to expand the use of organs from donation after cardiac death (DCD) donors. The focus on DCD, previously referred to as non–heart-beating donor (NHBD), has led to significant increases in its utilization (Table 1), although the contribution to the donor pool remains only 7% in the United States and is disproportionately reflected in increased kidney transplants (Table 2). Prior to the acceptance of brain death, donors were required to have cessation of heart function in order to procure organs for transplantation. In some areas where brain death legislation has not been widely adopted, such as Asia, DCD represents a significant source of organs for transplantation. Although the Maastricht Conference on DCD in 1994 identified 4 categories of DCD [Category I: dead on arrival; Category II: unsuccessful resuscitation; Category III: waiting cardiac death; and Category IV: cardiac death in a braindead donor], it is easier to envision DCD based on two distinct populations, one following uncontrolled cardiopulmonary arrest (Categories I and II) and the other under conditions of controlled removal from life support, without the criteria for brain death being fulfilled. In 1995, the University of Pittsburgh provided one of the earliest comparisons between controlled and uncontrolled DCD. There were 24 DCD livers, 14 in the uncontrolled group (Group 1) and 10 in the group in which controlled termination of life support was performed in the operating room (Group 2). Of the liver grafts that were used, the immediate graft function rate was 50% (3/6) in Group 1 and 100% (6/6) in Group 2; however, the overall 2-year patient and graft survival was only 58% and 33%, respectively. In order to improve outcomes with DCD donors, the decision was made to avoid using uncontrolled DCD livers and, with further experience, to more carefully control risk factors [e.g., avoidance of old ( 60 year old) DCD donors, avoidance of donors with long ( 60 minutes) warm ischemic times during procurement, avoidance of confounding factors in the DCD donors, and minimization of cold ischemic times]. While patient survival and graft survival have improved in more recent eras, the impact of DCD on liver transplantation, as assessed from the Scientific Registry of Transplant Recipients (SRTR) database, shows that DCD graft survival was significantly lower than that of donation after brain death (DBD) grafts, with 1and 3-year graft survival of 70.2% and 63.3% for DCD recipients versus 80.4% and 72.1% for recipients of livers from conventional DBD donors. Recipients of a DCD graft had a greater incidence of primary nonfunction (11.8 versus 6.4%) and retransplantation (13.9% versus 8.3%) compared with DBD recipients. Similar findings have also been reported at single centers 12,13 The mandated period of warm ischemia imposed during the process of certifying death in controlled DCD leads to stagnation of blood in the microcirculation.