Long-term renal function in heart transplant recipients receiving cyclosporine therapy

Background: Immunosuppression with cyclosporine has improved allograft function and reduced both morbidity and mortality in organ transplantation. However, cyclosporine-induced nephrotoxicity still is a concern. The purpose of our study was to evaluate the effects of cyclosporine on renal function in orthotopic heart transplant recipients. Methods: Thirty-nine patients who received transplants from 1985 to 1991 and had at least three yearly glomerular filtration rate measurements posttransplantation by ¹²⁵I- iothalamate clearance method were included in the study. In addition, serum creatinine (before and after transplantation) and cyclosporine doses were analyzed. Results: Maintenance immunosuppression at 1 year consisted of prednisone (0.1 mg/kg/day), azathioprine (2 mg/kg/day), and cyclosporine (12- hour trough level 100 to 150 ng/ml by fluorescence polarization immunoassay). The mean serum creatinine at 1 year was significantly higher than the mean pretransplantation serum creatinine (1.51 ± 0.32 versus 1.28 ± 0.38, p < 0.05) and stabilized after the first year. The mean glomerular filtration rate by ¹²⁵I-iothalamate clearance method was 70.6 ± 20.3 ml/min/1.73 m² (range 32 to 105) at l year and remained relatively stable during the follow- up period of up to 7 years. Creatinine clearance calculated by the Cockcroft and Gault formula overestimated the true glomerular filtration rate after the third year. The mean cyclosporine dosage was significantly lower after the first-year dose of 3.9 ± 1.8 mg/kg/day (p < 0.05). Three patients in 39 started hemodialysis at 5, 7, and 10 years after transplantation. Conclusion: Our data indicate that the adequacy of renal function is preserved with long- term cyclosporine therapy in heart transplant recipients.