Bioprpstjetoc cardiac va; ves fail from biological and metabolic as well as mechanical reasons, and the limited durability is the main factor of marked withdrawal in their clinical use. Starting the use of bioprosthetic valves in 1976, up to the
end of
1992, the consecutive 178 patients have undergone re-replacement of glutaraldehyde-treated xenograft valves for primary tissue failure(PTF) among the patients who had initial valve replacement at Seoul National University Hospital. The explanted
valves
were 69 porcine aortic(51 Hancock, 12 Angell-Shiley and 6 Carentier-Edwards) and 141 bovine pericardial (129 standard-profile and 12 low-profile Ionescu-Shiley) valves, with an overall incidence of PTF of 15.2%. The operative mortality rate of
re-replacement was 5.1%.
Calcific degeneration and tissue damage in relation to calcification were the most frequent modes of PTF on gross examinatin of the explanted valves resulting hemodynamically in valvular regurgitation.
The number of Hancock porcine and the standard-profile Ionescu-Shiley valves in mitral position were comparable to stady the characteristics of pattern of PTF. While the Hancock cahes in mitral position failed more often from tissue damage(tears,
holes,
and loss or destruction of cuspal tissue) then calcification(68.3% vs, 39.0%, p<0.01) with resultant regurgitation in 61%, the Ionescu-Shiley valves in the same position did more frequonthy from caleification the tissue damage(71.3% vs, 33.3%;
p<0.001)
with stenosis in 53%. The tendency of more calcification than tissue damage(71.3% vs. 33.3%, p<0.001) with stenosis in 53%. The tendency of more calcification and immobility of cusps in the latter group was partly explainable by the inclusion of
patients of pediatric age.
Observation made in this study suggest: many of bloprosthetic valves would fail from calification and tissue damage: some fail prematurely because of mechanical stress probably owing to the valve design in construction; and even those valves
escaped
early damage would be subjected to calcify in the prolonged follow-up period. In conclusion, at the present time, the clinical use of bioprosthetic xenograft valves seem to be quite limited until further improvement in biocompatibility and
refinement in
valve design in manufacture are achieved. (Korean J Thoracic Cardiovas Surg 1993;26:667-76)
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