Use of sirolimus in pediatric heart transplant patients: A multi-institutional study from the Pediatric Heart Transplant Study Group

Background Proliferation signal inhibitors, such as sirolimus, are increasingly used in solid-organ transplantation. However, limited data exist on sirolimus-treated pediatric patients. We aimed to describe sirolimus use in pediatric heart transplant patients and test the hypothesis that sirolimus use is associated with improved outcomes. Methods A retrospective review and propensity-matched analysis of the Pediatric Heart Transplant Study database was performed on patients undergoing primary heart transplantation from 2004 to 2013 with at least 1 year of follow-up comparing patients treated vs not treated with sirolimus at 1 year after transplant. The primary outcome of interest was patient survival, with secondary outcomes including cardiac allograft vasculopathy, rejection, malignancy, and renal insufficiency. Results Between 2004 and 2013, 2,531 patients underwent transplantation. At least 1 year of follow-up was available for 2,080 patients, of whom 144 (7%) were on sirolimus at 1 year post-transplant. Sirolimus-treated and non-treated patients had similar survival in the overall cohorts and in the propensity-matched analysis. The secondary outcomes measures were also similar, including a composite end point of all outcome measures. There was a trend toward increased time to cardiac allograft vasculopathy (p = 0.09) and decreased time to infection (p = 0.05) among sirolimus-treated patients in the overall cohort (p = 0.19) but not in the propensity-matched cohort (p = 0.17). Conclusions Sirolimus was used in less than 10% of patients at 1 year post-transplant. Overall outcomes of sirolimus treated and non-treated patients were similar with respect to survival and major transplant adverse events. Further study of sirolimus in pediatric heart transplant patients is needed.