A longitudinal perspective on neurodevelopmental outcome after infant cardiac transplantation

Background: With improvement in medical outcomes, the current research has shifted toward understanding and enhancing the quality of life after pediatric heart transplantation. Previous research has indicated that infant heart transplant recipients are generally at risk for neurodevelopmental delays; however, no longitudinal studies exploring the patterns of development within this medical population have been performed. Methods: Using the Bayley Scales of Infant Development-II, 39 children (2 to 38 months of age) who underwent heart transplantation in infancy (<1 year) at Loma Linda University Children's Hospital were assessed consecutively over time. Results: Mean Mental Development Index (MDI) scores for all age groups were within normal limits, except for the age ranges of 18 to 23 and 24 to 35 months, which were mildly delayed. Average Psychomoter Development Index (PDI) scores for all age groups reflected mildly delayed performance, except for the 36- to 38-month age group, which was within normal limits. Repeated measures analyses of variance on a sub-set of participants with at least 4 consecutive assessments revealed within-subject effects on MDI scores (F = 5.7, P < 0.01), but not on PDI scores (F = 1.6, p = 0.22). Significant decreases,in MDI scores at 18 and 28 to 36 months were noted. Conclusions: Motor development in this population was consistently mildly delayed. Age-dependent variability in cognitive skills was apparent. The delays appeared due to speech/language acquisition (18 months), and abstract reasoning/goal-directed behaviors (28 to 36 months). Possible etiologies for cognitive delays include test artifacts, auditory functioning and effects of immunosuppressive agents. Understanding risk factors in this patient population will allow for early and effective intervention.