Coronary Atherosclerosis

Moore than 17,000 orthotopic heart transplants have been performed, and the results of all centers reporting to the International Registry show a 1-year survival rate of more than 80%. Heart transplantation has become a routine and effective method for the treatment of end-stage heart disease. Acute cellular rejection or infection are the most common causes of death within the first year after transplantation. However, because of the progressive adaptation that occurs by the host to the transplanted organ, the incidence of cell-mediated rejection diminishes with time. Immunosuppression can thus be reduced after the first few months, and the incidence of infection therefore also lessens. The predominant cause of graft loss after the first year is the progressive development of graft atherosclerosis. Because of the denervated state of the transplanted heart, it is most unusual for transplant patients to experience angina, and regular monitoring for this condition must be carried out. The precise etiology of graft atherosclerosis has been hard to determine. It is probably the result of endothelial injury by antibody directed against the graft, and similar lesions can be generated by direct injection of antibody in the vessels of experimental animals' or in experimental cardiac grafts in inbred rats, in which it is absent in isograft controls.2 All organ grafts are affected,3 but nowhere is the effect as serious as in cardiac transplantation, with the myocardium particularly dependent on an unimpeded blood supply and the patient on the graft. Analysis has been made of various characteristics of both donor and recipient to attempt to identify predisposing causes. This has been unrewarding. In the experience of most centers, donor age or sex appears to be unrelated to the late development of vascular disease.45 Early in the clinical experience of heart transplantation, it was noted that graft atherosclerosis equally affected those recipients whose presenting illness was cardiomyopathy and those who suffered from end-stage coronary artery disease,6 and this has since been con-