Introduction: Recipient age is a well-established risk factor in heart transplantation. Although older recipients have worse survival, incidence of posttransplantational complications is higher in younger recipients, and so far there is no clear evidence of exact pathophysiological mechanism driving the latter. However, it is well known that younger patients have worse therapy compliance. (1, 2) In this study, we investigated if there is difference in achieving target immunosuppressive drugs levels according to age, and if it is associated with worse outcomes.

Patients and Methods: This is a single center, retrospective study that included 114 adult consecutive patients who underwent heart transplantation from 2010.-2015., and of those 94 with at least 30-day follow up were selected for further analysis (median age 54, 71 male, median follow-up 28 months). Study population was divided into 2 groups according to age. We observed outcomes of overall survival, graft rejection episodes that were treated, and occurrence of vasculopathy. Immunosuppressive drug levels at days 30, 180, and 365 after heart transplantation were collected (Table 1). Pearson chi-squared, and Mann-Whitney tests were used for group comparisons, while Kaplan-Meier curves were used for survival analysis.

Results: Although significantly higher number of younger patients had subtherapeutic immunosuppressive drug levels at day 30, at other time points there was no difference; as well as there was no difference in outcomes among younger patients according to drug levels. Furthermore, taking into account all the patients, there was no difference in outcomes based solely on subtherapeutic drug levels. Study groups differed significantly only in incidence of graft rejection requiring treatment, that was more frequently observed in younger group of patients.

Conclusions: In our study population we achieved target immunosuppressive drug levels harder in younger patient at 30-days after heart transplantation, however without influence on survival. Furthermore, younger patients had similar survival and occurrence of vasculopathy as older patients, and higher occurrence of graft rejection requiring treatment.