Background: Allograft conduits (AC) are used for reconstruction of the right ventricular outflow tract (RVOT) in children with RVOT hypoplasia or atresia and for pulmonary valve replacement in children undergoing Ross aortic valve replacement (AVR). Children undergoing the Ross AVR are generally older and have their AC inserted in the orthotopic position as opposed to the heterotopic position used for most cases of complex RVOT obstruction. The orthotopic position of the AC combined with the fact that the AC in the Ross patients are larger and can be oversized are the three factors that increase the right ventricular-pulmonary artery (RV-PA) conduit durability in the Ross AVR group. A retrospective evaluation of our experience with use of AC in non-Ross patients for reconstruction of the RVOT was conducted to determine the risk factors for failure.
Methods: Between January 1985 and December 2003, 117 non-Ross patients received AC (94 pulmonary and 23 aortic) for RVOT reconstruction. Median age at implantation was 8 months (mean 4.3 +/- 7.1 years; range, 6 days to 43 years). There were 57 children (49%) less than 12 months of age. Endpoints were AC failure (valve explant, balloon dilatation), and AC dysfunction (AC stenosis >40 mm Hg and AC insufficiency more than 2+). There were no device-related deaths.
Results: Overall patient survival was 80% at 15 years. Freedom from AC failure was 60% at 5 years and 43% at 15 years. Freedom from failure was worse in infants (42% and 34% at 5 and 15 years, respectively). Freedom from AC dysfunction was 40% at 5 years and 23% at 15 years. Freedom from dysfunction was worse in infants (21% and 16% at 5 and 15 years, respectively). Univariate analysis identified younger patient age, smaller AC size, diagnosis of truncus arteriosus, and the presence of aortic AC as risk factors for AC dysfunction and failure. Multivariate analysis identified smaller AC size and the presence truncus arteriosus as risk factors for AC dysfunction and failure.
Conclusions: Right ventricular outflow tract reconstruction with an AC in non-Ross patients has poor performance at midterm follow-up with AC dysfunction and failure of, respectively, 60% and 40% for the entire group and 79% and 58% in the infant group at 5 years. An alternate conduit for this application must be considered.