Durability of down-sized homografts for the reconstruction of the right ventricular outflow tract

OBJECTIVES: Small-sized homografts are rare but may be required for the reconstruction of the right ventricular outflow tract (RVOT). Down-sizing adult-sized homografts can be an option to overcome the shortage of availability. METHODS: Since 1994, we have been down-sizing adult-sized homografts by excising one cusp. The aim of the study was to analyse the durability of down-sized homografts and compare it with small-sized homografts in a paediatric population. All patients below a body weight of 14 kg were included in the study. The end-point of the study was homograft failure. RESULTS: A total of 152 patients met the inclusion criteria of the study, of which 82 patients (54%) received a down-sized homograft. The median age was 17.1 (0.3-64.8) months and the mean weight 8.4 ± 3.4 kg. Fifty-eight patients (38%) were under 1 year and 10 (6.5%) under 1 month of age at the time of homograft implantation. The mean homograft size of the whole study population was 14.7 ± 2.5 mm and the mean z-score was 1.6 ± 0.9. The median follow-up time was 10 (0.03-19.7) years. Early mortality after homograft implantation was 5% (n = 8), 4 of these patients had received a down-sized homograft. The study population comprised early survivors, that is, 144 patients. During follow-up, a total of 46 homografts failed, 23 in each group, after a mean time of 5.7 ± 4.2 years. Freedom from homograft failure was 94.6 ± 2.6, 87.2 ± 4 and 68.6 ± 6.6% for down-sized homografts and 95.2 ± 2.7, 78.7 ± 5.5 and 61 ± 7% for small-sized homografts at 1, 5 and 10 years, respectively (P = 0.3). Risk factors for homograft failure in the multivariable analysis were a homograft z-score of <1 and age below 1 year at the time of implantation (P = 0.02). CONCLUSION: Down-sized homografts demonstrated a durability similar to that of small-sized homografts. Therefore, down-sizing adultsized homografts by creating a bicuspid valve to fit into the corresponding RVOT in children with congenital heart defects is an excellent method to overcome the shortage of small-sized homografts.