Transplant coronary disease: nonimmunologic risk factors

Since the time that coronary artery disease was first described in the transplanted human heart, attempts have been made to define risk factors for its development. Although recent reports have emphasized immunologic and infectious (i.e., cytomegalovirus) mechanisms in the development of transplant coronary disease, the influence of several nonimmunologic risk factors has also been studied. Some of the nonimmunologic risk factors that have been evaluated include recipient characteristics (age, sex, obesity, hyperlipidemia, hypertension, smoking, diabetes mellitus, pretransplantation heart disease), donor characteristics (age, sex), immunosuppressive agents/protocols, and nonimmune mechanisms of endothelial injury (cyclosporine, ischemic time). Studies evaluating the role of these risk factors have produced variable results. One or more studies, however, have suggested an effect of recipient age and sex, donor age and sex, obesity, hyperlipidemia, pretransplantation diagnosis, and ischemic time on the development of transplant coronary disease. The most consistently described relationship has been between hyperlipidemia and transplant coronary disease. Hyperlipidemia is common after heart transplantation, with elevations noted in total cholesterol, low-density lipoprotein cholesterol, and triglycerides. The cause of posttransplantation hyperlipidemia is not well defined, but obesity and the immunosuppressive agents prednisone and cyclosporine play a role. Treatment of posttransplantation hyperlipidemia can be difficult because commonly used lipid-lowering agents have side effects and interactions with immunosuppressive drugs that necessitate caution in their use in the posttransplantation population. Transplant coronary disease almost certainly has a multifactorial cause, with endothelial injury and nonimmunologic risk factors, particularly hyperlipidemia, playing contributory roles. Because hyperlipidemia and the obesity that commonly accompany it are modifiable risk factors, weight loss and treatment of hyperlipidemia are recommended.(ABSTRACT TRUNCATED AT 250 WORDS)