Donor-recipient size matching in pediatric heart transplantation: a word of caution about small grafts.

BACKGROUND: The increased shortage of donor organs led centers to extend the conventional donor criteria, particularly regarding donor-recipient size mismatching. Little information is available in the pediatric age group.
METHODS: Between December 1987 and May 1994, 73 pediatric orthotopic heart transplantations were performed. Indications for heart transplantation included congenital heart defect (29 patients), cardiomyopathy (40 patients), valvular disease (1 patient), and retransplantation (3 patients). Patients ranged in age from 9 days to 18 years (mean: 5.7 +/- 5 years). The following factors were evaluated: cardiomyopathy, congenital heart disease, age, pretransplantation pulmonary hypertension, previous sternotomy, status at transplantation, donor to recipient weight ratio, graft ischemic time, degree of donor inotropic support, ABO compatibility, gender mismatch.
RESULTS: The overall mortality rate before discharge (7 days to 4.5 months) was 27.4%. Donor heart failure occurred in 31.5%. Donor heart failure and early mortality were strongly correlated (p = 0.0002). Risk factors for donor heart failure were pretransplantation pulmonary hypertension (p = 0.024), donor/recipient ratio (p = 0.033), and major donor inotropic support (p = 0.034). Donor heart failure rate was 50% in donor/recipient ratio less than 1, 33% in donor/recipient ratio between 1 and 1.6, and 7% in donor/recipient ratio more than 1.6. Donor/recipient ratio less than 1 was the only significant risk of postoperative death by univariate (p = 0.0045) and multivariate (p < 0.01) analysis.
CONCLUSIONS: Donor heart failure remains the main cause of early mortality in pediatric heart transplantation. The use of oversized donor may be beneficial, particularly in patients with pretransplantation pulmonary hypertension. The use of undersized donor grafts should be strongly discouraged.