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Pathophysiology of early failure of autologous aortic heart valves (ATCV)
1Department of Cardiothoracic and Vascular Surgery, University Hospital, Mainz, Germany.
Background:
Degeneration remains the major drawback of bioprostheses. Among various concepts to mitigate degeneration, the use of autologous pericardium for intraoperative construction of aortic valves (ATCV) was revived recently. Based on in-vivo studies the problem of tissue failure was claimed to be oversome by short immersion in glutaraldehyde.
Methods:
Two often ATCV implanted 1994-1996 had to be replaced because of valvular insufficiency due to leaflet shrinkage or tearing. Pathophysiology of failure was evaluated by light microscopy and immune histology, scanning electron microscopy (SEM) and determination of tissue calcium content (AAS).
Results:
AAS revealed 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 showed smooth surfaces in the 'normal' and exposure of collagen in the degenerated leaflet associated with calcification. Tears occurred close to the stents.
Conclusions:
Failure of ATCV is characterised by either shrinkage and calcification despite a short tanning or by tearing related to the stent design. Clinical use of ATCV cannot be recommended at present.