Pathophysiology of early failure of autologous aortic heart valves (ATCV)

Background: Degeneration remains the major drawback of bioprostheses. Among various concepts to mitigate degeneration, the use of autologous pericardi um for intraoperative construction of aortic valves (ATCV) was revived rece ntly. Based on in-vivo studies the problem of tissue failure was claimed to be oversome by short immersion in glutaraldehyde. Methods: Two of ten ATCV implanted 1994-1996 had to be replaced because of valvular insufficiency d ue to leaflet shrinkage or tearing. Pathophysiology of failure was evaluate d by light microscopy and immune histology, scanning electron microscopy (S EM) and determination of tissue calcium content (AAS). Results: AAS reveale d high calcium levels in the shrunken and low levels in the torn leaflets. Histology demonstrated extensive fiber degeneration without inflammation in the destructed and moderate degeneration in the intact leaflets. SEM showe d smooth surfaces in the 'normal' and exposure of collagen in the degenerat ed leaflet associated with calcification. Tears occurred close to the stent s. Conclusions: Failure of ATCV is characterised by either shrinkage and ca lcification despite a short tanning or by tearing related to the stent desi gn. Clinical use of ATCV cannot be recommended at present.