Middle to long-term outcomes and pathological changes of implanted expanded polytetrafluoroethylene valved conduits.

Objectives: This study evaluated the mid to long-term outcomes of expanded polytetrafluoroethylene valved conduits and preliminarily explored the reasons for conduit failure. Methods: The study included patients who received reconstruction with ePTFE valved conduits between June 2014 and March 2025. Echocardiography was used to evaluate the conduit function. Histopathological staining was applied to demonstrate the details of the failure conduits. Results: 104 patients had a median age of 90 months (interquartile range, 44.25-144 months) and a median follow-up of 48 months (IQR, 16-54.25 months). 4 early deaths (3.8 %) and 1 late death (1.0 %) occurred. 28 conduits (26.9 %) were detected with dysfunction, with 10 (9.6 %) progressing to failure. Infective endocarditis only occurred in 2 patients (1.9 %). 7 patients (6.7 %) received re-interventions, including 2 percutaneous interventions, 1 replacement after percutaneous intervention, and 4 direct replacements. Pathological staining showed no thrombus formation, but calcification on the valve junction. The valved conduit exhibited insufficient endothelialization, accompanied by the infiltration of inflammatory cells and remarkable neointimal hyperplasia. Conclusions: The application of the ePTFE valved conduit presented low mortality rate and relatively appreciable conduit function. Conduit stenosis was the main cause of failure, characterized by calcification and neointimal hyperplasia, and might be related to inflammatory response and material damage.