Background and aim of the study: Right ventricular-to-pulmonary artery (RV-PA) conduits are implanted in the right ventricular outflow tract (RVOT) of children, with the knowledge that future reoperation will likely be required. The authors' experience of conduit RVOT reconstruction was reviewed in order to assess the frequency of conduit replacement and to determine risk factors for conduit dysfunction and failure.
Methods: Between January 1980 and April 2007, a total of 261 patients (mean age 8.7 +/- 11.7 years) underwent primary RVOT reconstruction with an RV-PA conduit at the authors' institution. There were 19 (7%) early deaths. Among the survivors, 84 (35%) underwent conduit explant at the implanting hospital with insertion of a second conduit at a mean of 6.0 +/- 3.7 years (range: 7 months to 22 years) after the first implantation. The primary operation and reoperation patient groups were compared with regard to the incidence of early death, late death, conduit-related intervention without explant, and conduit explant.
Results: Six risk factors for mortality were significant on univariate analyses: surgery before 1992 (p = 0.005), age <3 months (p = 0.001), diagnosis of truncus arteriosus (p <0.001), reconstruction with allografts (p = 0.05), association with interrupted aortic arch (p = 0.05) and with truncal valve insufficiency (p = 0.05). Of these six factors, only the diagnosis of truncus arteriosus (p = 0.001) and surgery before 1992 (p = 0.05) remained significant by multivariate analysis. Univariable analysis was performed for multiple factors, of which the following were found to be significant: body weight (p <0.003), age (p = 0.002), conduit diameter (p <0.0001), conduit type (p = 0.006), and diagnosis of truncus arteriosus (p <0.0001). Multivariable analysis of significant univariable risks revealed small allograft diameter (p <0.001) and diagnosis of truncus arteriosus (p <0.001) to be significant risk-factors for need of replacement.
Conclusion: Most RVOT conduits placed in children will eventually require replacement. Patient survival for conduit replacement is comparable to that for primary conduit placement. Reoperative conduit RVOT reconstruction is possible, with low morbidity and mortality.