OPPORTUNISTIC INFECTIONS IN THE CARDIAC TRANSPLANT PATIENT

The risk of opportunistic infection in the cardiac transplant patient is determined by the interaction between the epidemiologic exposures t hat the patient encounters and the patient's net state of immunosuppre ssion. The epidemiologic exposures include those encountered in both t he community and the hospital, with the latter being more important as they usually occur at a point in time when the patient's net state of immunosuppression is at its highest. The net state of immunosupressio n is a complex function whose major determinants are the immunosuppres sive program and the presence or absence of infection with a group of immunomodulating viruses, particularly cytomegalovirus. Strategies for preventing opportunistic infection in this patient population are bas ed on the following factors: technically impeccable surgery, precisely managed immunosuppression, environmental protection (particularly in the hospital), and the use of preventative antimicrobial strategies. T hese last are of two types, prophylactic and preemptive. The key point in both these approaches is to link the preventative strategy to the intensity of the immunosuppressive program and to target the antimicro bial program to the time period and patient group at greatest risk For most opportunistic infections this is the time period 1 to 6 months a fter transplantation (when viral infections are prevalent), and the sm all group of patients more than 6 months after transplantation who are chronically overimmunosuppressed because of rejection.