The profile of renal function over time in a cohort of pediatric heart transplant recipients.

To assess the burden over time of renal dysfunction in pediatric heart transplant patients using an objective measure on an annual basis for serial comparison. GFR was measured at regular interval by nuclear medicine scintigraphy. Results were analyzed in relation to age, time post-transplantation, gender, and average calcineurin-inhibitor dose for the first two months post-transplantation. Results were compared with cGFR using the Schwartz equation. A total of 91 patients (56 males) transplanted between 1990 and 2004 underwent 373 GFR measurements. Median age at transplantation was 3.3 yr (birth - 17.8). Median first GFR at 0.7 yr (0.1-4.1) post-transplant was normal (94 mL/kg/1.73 m(2)). Freedom from at least mild renal insufficiency was 84% and 33% at one and five years post-transplant. Females had better renal function early post-transplant (GFR 105 mL/min/1.73 m(2)) but an increased probability of an abnormal GFR over time. Higher calcineurin inhibitor dose in the first two months post-transplantation was associated with an increasing probability of an abnormal GFR over time. The cGFR overestimated the measured GFR by 33 +/- 26 mL/kg/1.73 m(2). Renal insufficiency is an important morbidity after pediatric transplantation with the majority of patients experiencing at least mild renal dysfunction. Calculated GFR significantly underestimates the burden of renal insufficiency in this patient population.