Valved conduits are often required to replace pulmonary arteries (PA). A widely used Contegra device is made of bovine jugular vein (BJV), preserved with glutaraldehyde (GA) and iso-propanol. However, it has several drawbacks that may be attributed to its chemical treatment. We hypothesized that the use of an alternative preservation compound may significantly improve BJV conduit performance. This study aimed to compare the macroscopic and microscopic properties of the BJV treated with diepoxide (DE) and GA in a porcine model. Twelve DE-BJVs and four Contegra conduits were used for PA replacement in minipigs. To assess the isolated influence of GA, we included an additional control group—BJV treated with 0.625% GA (n = 4). The animals were withdrawn after 6 months of follow-up and the conduits were examined. Explanted DE-BJV had a soft elastic wall with no signs of thrombosis or calcification and good conduit integration, including myofibroblast germination, an ingrowth of soft connective tissue formations and remarkable neoangiogenesis. The inner surface of DE-BJVs was covered by a thin neointimal layer with a solid endothelium. Contegra grafts had a stiffer wall with thrombosis on the leaflets. Calcified foci, chondroid metaplasia, and hyalinosis were observed within the wall. The distal anastomotic sites had hyperplastic neointima, partially covered with the endothelium. The wall of GA-BJV was stiff and rigid with degenerative changes, a substantial amount of calcium deposits and dense fibrotic formations in adventitia. An irregular neointimal layer was presented in the anastomotic sites without endothelial cover in the GA BJV wall. These results demonstrate that DE treatment improves conduit integration and the endothelialization of the inner surface while preventing the mineralization of the BJV, which may reduce the risk of early conduit dysfunction.

Background/Objectives: Bovine pericardial valve conduits (PVCs) are commonly used for right ventricular outflow tract reconstruction in both pediatric and adult patients. Calcification, particularly prevalent in children and young adults, is a leading cause of conduit failure and is affected by the chemical composition of the treated biomaterials. In this study, we aimed to compare the structural changes in diepoxy-treated (DE-PVCs) and glutaraldehyde-treated PVCs (GA-PVCs) and to identify factors contributing to tissue mineralization in a large animal model. Methods: Pulmonary artery replacement was performed in minipigs (33–88 kg) using twelve DE-PVCs and four GA-PVCs. After six months, the animals were euthanized, and the explanted PVCs underwent macroscopic and microscopic examination. Results: Large calcium deposits formed along conduit joining suture (CJS) lines in all PVCs, regardless of the cross-linking agent. Mineral clusters surrounded the multifilament braided thread, and its fibers were encrusted with hydroxyapatite crystals. In DE-PVCs, no mineralization occurred outside the suture lines, and they showed successful integration and graft vitalization with a uniform neointima and well-developed endothelial monolayer. GA-PVCs developed a rigid external capsule, foci of collagen fiber calcification within the walls, and neointimal hyperplasia with limited endothelial coverage. Conclusions: In PVCs, calcification predominantly occurs along the CJS lines, where the multifilament suture acts as a nucleation site for hydroxyapatite crystals. DE treatment prevents collagen mineralization, unlike GA, and offers better integration, reduced neointimal hyperplasia, and a well-developed endothelial layer. These findings suggest that DE-PVCs may be a superior option for pediatric cardiac surgery by reducing calcification and improving conduit durability. Overall, the results will help optimize PVC manufacturing strategies to lower the risk of conduit failure.