Immunohistological findings for an extracardiac conduit in Fontan pathway constructed with pedicled autologous pericardium

Although autologous pericardium has been used in pedicled fashion for various reconstructive procedures in congenital cardiovascular surgery with the expectation that it will be able to grow and remain viable after implantation, no clinical study has evaluated the histological characteristics of implanted pedicled pericardium long after previous implantation. We describe herein histological findings of pedicled pericardium, which had been used for three years as an extracardiac conduit in Fontan pathway. A four-year-old boy with a history of Fontan operation using pedicled autologous pericardial roll required conduit replacement three years after the previous operation, and resected pericardial tissue was examined immunohistologically. Staining for CD34 revealed abundant microvasculature, suggesting preservation of viability. Staining for factor VIII demonstrated the presence of endothelium on the luminal surface of the conduit. Elastica-van Gieson staining revealed a band of elastic tissue, which is generally found not in the native pericardium but in the vascular wall structures. These findings suggested that the pedicled pericardium thus appeared to have remained viable and might have differentiated to resemble tissue of the vascular wall after having been used in Fontan pathway.