Renal function after pediatric cardiac transplantation: the effect of early cyclosporin dosage.

BACKGROUND: There is little data on renal function in pediatric heart transplant recipients. Early rejection is a major concern and most units run high cyclosporin A (CyA) levels during the 2 to 3 months after transplantation. We sought to document long-term renal function after transplantation and to assess influence of early CyA levels.
METHODS: We reviewed all of our pediatric transplants between June 1985 and August 1998 who survived longer than 6 months (n = 54). Glomerular filtration rate (GFR) was estimated at 1, 2, 4, and 8 years posttransplantation using the Schwartz formula: GFR (mL/min/1.73m(2)) = [Ht(cm)/creatinine(micromol/L)] x X We also analyzed whether change in renal function correlated with trough CyA levels.
RESULTS: Median age at transplant was 4 years and median follow-up was 5 years. Survival rates were 87% at 1 year and 80% at 5 years. Mean GFR pretransplant was 79 +/- 19 mL/min/1.73 m(2), reflecting prerenal impairment. One year later, mean GFR was 72 mL/min/1.73 m(2); after 2 years it was 65 mL/min/1.73 m(2), after 4 years (n = 35) it was 60 mL/min/1.73 m(2), and after 8 years (n = 14) it was 57 mL/min/1.73 m(2). CyA levels during the first 2 months correlated with the change in GFR during the first year (r(2) = 0.21).
CONCLUSIONS: This study demonstrates for the first time that decline in renal function after heart transplantation correlates with early CyA exposure; this dysfunction persists even when CyA doses are subsequently reduced.