Background: Because of the severe shortage of neonatal organ donors, oversized cardiac allografts are frequently transplanted. This study examined body and graft growth of neonates who receive an oversized heart.
Methods: We studied 51 neonates, who received transplants between November 1986 and August 1992, for changes in body weight, left ventricular mass, and end-diastolic volume measured at 1 week, 1, 3, and 6 months, and yearly after cardiac transplantation. Patients were divided into two groups according to donor/recipient weight ratios: the normal group, where the donor/recipient weight ratio was 1.5 or less (1.06 +/- 0.05; n = 24), and the oversized group, where the donor/recipient weight ratio was more than 1.5 (2.22 +/- 0.10; n = 27).
Results: After cardiac transplantation, body weight increased continuously in both groups with no difference between groups. In the oversized group, left ventricular end-diastolic volume at 1 week and left ventricular mass at 1 week and 1 month were significantly higher than those in the normal group (p < 0.01). In the normal group, end-diastolic volume and left ventricular mass increased continuously. In the oversized group, however, left ventricular mass significantly decreased until 3 months after cardiac transplantation and then increased continuously, whereas end-diastolic volume increased continuously throughout the posttransplantation period.
Conclusions: These data suggest that oversized cardiac allografts shrink at first and then grow as the recipient grows. There appears to be a size adaptation of the large cardiac allograft to accommodate to the reduced requirements of the neonate.