Renal function and safety of heart transplant recipients switched to mycophenolate mofetil and low-dose cyclosporine.

Background: We evaluated cyclosporine (CSA) dose reduction and mycophenolate mofetil (MMF) treatment versus maintained CSA dosage and azathioprine (AZA) in HTX regarding renal function and safety from CSA nephrotoxicity (creatinine > 1.7 mg/dL).

Methods: Fourteen recipients (group 1: 12 men, 2 women) with CSA-based immunosuppression (plus azathioprine and/or steroids) were started on 2000 mg MMF/d. Azathioprine was discontinued and CSA tapered to trough whole blood levels of 70 to 120 microg/L. Ten recipients (group 2: seven men, three women) were maintained on their CSA dosages. Creatinine clearance, serum creatinine, uric acid, urea nitrogen, and rejection were monitored.

Results: Mean age was 58 (range 44 to 69 years) and 48 years (range 24 to 61 years) in groups 1 and 2, respectively. In group 1 creatinine fell from 2.7 +/- 0.8 to 1.9 +/- 0.5 mg/dL (baseline vs control 2: P =.001); uric acid and urea nitrogen remained constant. CSA levels decreased from 173 +/- 56 to 110 +/- 33 microg/L (P =.02). In group 2 creatinine (2.4 +/- 0.7 vs 2.3 +/- 0.5 mg/dL), uric acid, urea nitrogen, and CSA levels remained constant. Comparison between groups showed higher creatinine clearance (50 +/- 18 vs 29 +/- 14 mL/min; group 1 vs group 2: P =.02), lower CSA levels (110 +/- 33 vs 161 +/- 35 microg/L; P <.001) and a trend toward lower serum creatinine (1.9 +/- 0.5 vs 2.3 +/- 0.5 mg/dL, P =.077). There were two rejections >/= 1B according to ISHLT in the study and four in the control group. Two deaths occurred in each group.

Conclusions: Conversion from AZA to MMF after CSA reduction improves creatinine clearance in HTX recipients and reduces serum creatinine. No negative effect on patient safety was identified by rejection rate or survival.