Improvement of impaired renal function in heart transplant recipients treated with mycophenolate mofetil and low-dose cyclosporine

Background. Cyclosporine (CsA) nephrotoxicity is a common problem after car diac transplantation. We have studied the impact of CsA dose reduction in a ssociation with mycophenolate mofetil (MMF) treatment on renal function in heart transplant recipients with suspected CsA nephrotoxicity (serum creati nine level >2 mg/dl). Methods. Twelve heart transplant recipients (11 men, 1 woman; 111 to 1813 d ays after transplantation) with CsA-based immunosuppression (plus azathiopr ine and/or steroids) and a serum creatinine level >2.0 mg/dl were started o n a daily dose of 2000 mg of MMF. Dilated cardiomyopathy was the underlying disease in nine patients, ischemic cardiomyopathy in three patients. Mean patient age was 57 years (range 44-69 years). Azathioprine was discontinued and CsA slowly tapered. Creatinine clearance, serum creatinine level, urea nitrogen, and uric acid were monitored. CsA levels were measured, and CsA dose was adjusted for whole blood levels of 70-120 mu g/L. Ten patients sti ll had endomyocardial biopsies, whereas one had echocardiographic controls only. Results. One grade 1B rejection episode according to ISHLT (International S ociety for Heart and Lung Transplantation) was observed until 1 year after the switch to MMF. One patient was excluded due to gastrointestinal side ef fects. Conclusions. Conversion from azathioprine to MMF with consecutive reduction of CsA in heart transplant recipients with CsA-impaired renal function imp roves renal function as evidenced by lower serum creatinine, urea nitrogen, uric acid, and higher creatinine clearance.