Failure mode of a new pericardial valve prosthesis (Sorin Pericarbon). A morphological study.

Between February 1986 and February 1992, 144 patients (mean age 69 years) received 149 bovine pericardial valve bioprostheses (Sorin Pericarbon). Out of this group 10 patients required reoperation because of valvular dysfunction. Defect bioprostheses (7 aortic valves, 3 mitral valves), removed 34 to 81 months after implantation, were studied by X-ray analysis as well as light and electron microscopy. Seven out of ten valves were explanted because of valvular stenosis, two valves had to be replaced because of valvular regurgitation and one because of paravalvular leakage. X-ray analysis revealed severe clacification of the cusps in all cases. Mineralization occurred predominantly next to commissural attachment zones. Cuspal tearing, associated with calcific degeneration of the tissue, was observed in two cases. Beside the commissures, accelerated tissue degeneration could be detected near the basal suture line: disintegration of collagen bundles by invading macrophages and mineral deposits was prominent in these regions. Scanning electron microscopy revealed the presence of circumscribed areas of endothelial-like cell lining on both surfaces of the cusps of five explants. Valvular stenosis, caused by severe calcification of commissural as well as basal regions of the leaflets, is the principal failure mode of the Sorin Pericarbon heart valve prostheses. As an additional aspect, the basal suture line must be assumed to be a critical determinant in accelerating tissue degeneration. Long-term clinical studies will be required to evaluate the clinical performance of this valve, focusing on thromboembolic complications, hemodynamic function and long-term durability.