Determinants of renal function in pediatric heart transplant recipients: long-term follow-up study.

Background: Renal insufficiency (RI) is a known complication in heart transplant recipients. We sought to determine the prevalence and risk factors for RI in pediatric heart transplant recipients over a long-term follow-up period.

Methods: The study cohort included 77 pediatric heart transplant recipients (35 girls, 18 African Americans) who had a minimum follow-up of 1 year. Data were obtained from pre-transplant evaluations and at 1, 6 and 12 months post-transplant and annually thereafter. Factors evaluated for their influence on renal function included duration of listing, age at transplant, gender, race, cardiac diagnosis, use of assist devices, inotropic support, rejection episodes and use of calcineurin inhibitors.

Results: The median age at transplant was 2 years, with a median follow-up duration of 5.1 years. RI was prevalent in 33% pre-transplant, and in 17%, 21% and 25.9% at 1, 3 and 5 years post-transplant, respectively. Two patients developed end-stage renal disease requiring long-term dialysis, with 1 eventually receiving a renal transplant. Significant risk factors for RI were African-American race (p = 0.04), younger age at transplant (p = 0.007), duration of listing (p < 0.0001) and calcineurin inhibitor level (p = 0.003). RI at 6 months post-transplant predicted chronic kidney disease at 5 years (odds ratio = 9).

Conclusions: The prevalence of RI increased during a median follow-up of 5 years in this pediatric heart transplant cohort. African-American race, younger age at transplant, longer duration of listing, high level of calcineurin inhibitors and RI at 6 months were important determinants of RI. These patients should be followed-up carefully with early referral to a pediatric nephrologist if they develop chronic kidney disease.