Influence of donor age and donor-recipient age difference on intimal hyperplasia in pediatric patients with young and adult donors vs. adult patients after heart transplantation

Aim: Optimal selection and allocation of donor hearts is a relevant aspect in transplantation medicine. Donor age and cardiac allograft vasculopathy (CAV) affect post-transplant mortality. To what extent donor age impacts intimal hyperplasia (CAV^IH) in pediatric and adult patients after heart transplantation (HTx) is understudied.

Methods: In a cohort of 98 HTx patients, 58 pediatric (24.1% with adult donors) and 40 adult patients, we assessed the effect of donor age and donor-recipient age difference (D-R) on the continuous parameter of maximal intima thickness (mIT) in optical coherence tomography. We evaluated their predictive value regarding higher mIT and the prevalence of CAV^IH, defined as mIT > 0.3 mm, and compared it to established CAV risk factors.

Results: In the overall population, donor age correlated with mIT (p < 0.001), while in the pediatric subpopulation, both donor age and D-R correlated with mIT (p < 0.001 and p = 0.002, respectively). In the overall population, donor age was a main predictor of higher mIT and CAV^IH (p = 0.001 and p = 0.01, respectively) in addition to post-transplant interval, arterial hypertension, and dyslipidemia. In the pediatric patients, dyslipidemia remained a main predictor of both higher mIT and CAV^IH (p = 0.004 and p = 0.040, respectively), while donor age and D-R were not.

Conclusion: While there was an effect of the non-modifiable parameter of donor age regarding maximal intimal thickness, a stronger association was seen between the modifiable risk factor dyslipidemia and higher maximal intimal thickness and CAV^IH in both the overall population and the pediatric subpopulation.