Heart allograft rejection under varying immunosuppressive protocols as evaluated by endomyocardial biopsy.

Rejection episodes in 259 heart allograft recipients and 29 heart-lung transplant patients at Stanford University were examined from the viewpoint of endomyocardial biopsy. The patients were divided into the following six groups by immunosuppressive regimen: Group 1 (100 patients) was treated with conventional immunosuppression. Group 2 (26 patients) was treated with cyclosporine in combination with low-dose corticosteroids and an initial 3- to 4-day course of rabbit antithymocyte globulin. Group 3 (76 patients) was treated with cyclosporine and low-dose corticosteroids. Group 4 (34 patients) was treated with low-dose cyclosporine, azathioprine, and low-dose corticosteroids. Group 5 (23 patients) was treated with low-dose cyclosporine and azathioprine, but initially without low-dose corticosteroids. Group 6 was composed of 29 heart-lung transplant recipients. Groups 1, 2, and 6 had significantly less rejection episodes than group 3, and groups 4 and 5 had more rejection episodes than group 3. In patients with a diagnosis of mild acute rejection on cyclosporine, a repeat biopsy shows progression to a moderate acute rejection in 21% to 43% of cases, emphasizing the importance of this diagnosis even in cyclosporine-treated patients. The characteristics of acute heart allograft rejection as assessed by endomyocardial biopsy are important to recognize. In part as a result of the data presented here, further modifications in the immunosuppressive regimen of the Stanford heart and heart-lung transplant recipients are being undertaken.