Aortic valve re-replacement after Bentall procedure with a biological valved conduit in a sheep model.

BACKGROUND AND AIM OF THE STUDY: The Bentall procedure is the 'gold standard' for the repair of a combined pathology of ascending aorta and aortic valve. Because there is no need for long-term anticoagulation, biological-valved conduits have become increasingly popular; however, the possible need for reoperation due to valve degeneration is a major disadvantage. The aim of this animal-based study was to prove the feasibility of an isolated replacement of the aortic valve prosthesis six months after a previous implantation of a biological valved conduit (BioValsalva) in a sheep model. A total aortic root replacement, using the BioValsalva conduit, was performed in 10 juvenile sheep. After six months, the surviving sheep were reoperated on, and the stentless valve was replaced with a stented biological valve placed inside the previously implanted vascular conduit. RESULTS: Five animals survived the initial implantation of a BioValsalva conduit. During reoperation, the triple-layered vascular graft with polytetrafluoroethylene on the outside showed only slight adhesions with the surrounding tissue. The stentless valve was removed in one piece, after which a new stented valve was implanted inside the conduit. An X-radiographic examination of the explanted valve showed moderate calcification of the leaflet, and severe calcification of the aortic wall. CONCLUSION: The results of this animal study confirmed that a degenerated stentless biological valve inside the BioValsalva conduit could be replaced with a new valve, without having to remove the entire conduit.