Spontaneous Heterograft Aortic Valve Failure

Glutaraldehyde-treated porcine aortic valve prostheses have been in clinical use for ten years. The long-term durability of these valves remains unknown although they have functioned well in most large clinical series for more than five years. At the present time, several manufacturers produce bioprostheses mounted on flexible stents. This report concerns the failure of an Edwards porcine xenograft in the aortic position 15 months following implantation. At reoperation, the right and left coronary leaflets of the explanted valve were torn from the aortic wall. The loss of wall integrity suggests that during the process of mounting the xenograft on the flexible stent, the aortic walls of the bioprosthesis may have been thinned beyond a critical point of maintenance of wall strength. The pathological and clinical findings of similar cases are reviewed.