Age-related factors in child heart transplants

Age-related differences in the type, clinical presentation, pre-transplant management and post-transplant course of children with cardiomyopathy impact outcomes following heart transplant. Although infants have the highest incidence of cardiomyopathy in the pediatric population, adolescents comprise 49% of the children < 18 years of age transplanted with the diagnosis of cardiomyopathy. Death while waiting for a heart transplant is higher in the infant population and the lack of availability of suitable long-term mechanical support negatively impacts chances of survival to transplant in the younger child. Important age-related differences in morbidity and mortality occur following transplant in children. The etiology of these differences is multifactorial and includes biological and psychological factors. The relative immaturity of the neonatal immune system may confer a long-term survival benefit by decreasing rejection and coronary artery vasculopathy. The pharmacokinetics and pharmacodynamics of the immunosuppressive agents differ by age and may contribute to the effectiveness and toxicity of these medications. Age-specific limitations in cognitive, behavioral and psychological function have been also been identified in transplant recipients and influence survival and quality of life following transplant. Further efforts to characterize the relative importance of age-related differences on transplant outcomes are needed in order to enable effective implementation of age-specific management strategies in the care of pediatric transplant recipients.