Adaptive growth and remodeling of transplanted hearts in children.

Objective: We aimed to evaluate the adaptive growth and remodeling behavior of the transplanted heart in pediatric heart-transplant recipients by comparing donor body surface area (BSA) and cardiac dimensions during transplantation with the corresponding parameters of the recipient over a period of time.

Methods: A retrospective review of medical and echocardiographic records of 167 children (8.65 ± 5.98, median 9; range 0-17 years) who underwent orthotopic heart transplantation between 1987 and March 2010 was done.

Results: In the first 30 days post-transplantation, right- and left-ventricular end-diastolic diameters, volumes, and myocardial mass were found to be significantly increased (z score 3.96, p < 0.000) in relation to the recipients' BSA. Within the first year of post-transplantation, there was a significant reduction in the right-ventricular diameter (z score, -1.0 to +1.6, p = 0.000), left-ventricular diameter (z score -1.0 to +1.9, p = 0.000), right-ventricular end-diastolic volume (z score -1.3 to +1.9, p = 0.000) and left-ventricular end-diastolic volume (z score -1.3 to +1.8, p = 0.000), right-ventricular mass (z score, -1.4 to +1.7, p = 0.000) and left-ventricular mass (z score, -1.4 to +1.8, p = 0.000). During subsequent follow-up periods of 2-5 and 6-10 years, the aforementioned cardiac dimensions and volumes increased appropriately in accordance to the BSA (p = 0.000). In all the cardiac dimensions and volumes measured, donor-recipient mismatch did not influence the continuous growth of the measured parameters, which was in accordance to the recipients' BSA over time. Kaplan-Meier survival analysis showed a survival rate of 61.7% at 10 years. There is no statistically significant difference in survival rate among patients with varying donor-recipient weight ratios and donor-recipient BSA ratios (p = 0.53).

Conclusions: This study demonstrates that the transplanted heart undergoes remodeling processes and grows adaptively, in accordance to the BSA, over a period of time.