RESUMO
Structural deterioration is the major reason for reoperation in patients with valvular bioprostheses. We present findings on a mode of structural deterioration, the pathology of which has not yet been well characterized. Between January 1990 and December 1992, 39 Carpentier-Edwards standard valves (CESTD) and 50 Carpentier-Edwards supra-annular valves (CESAV) were operatively removed at St. Paul's Hospital. Of these, 14 bioprostheses (6 CESTD [15%] and 8 CESAV [16%]) showed dehiscence of a single commissural region from its stent post. Age at initial implantation was not significantly different between patients with CESAV (52.1 ± 5.4 years) and CESTD (45.5 ± 5.1 years, p = ns), but time from implantation to reoperation was shorter for CESAV as compared with CESTD (7.9 ± 0.5 vs. 13.3 ± 0.7 years, respectively, p < 0.01). The vast majority (12 14 ) of dehiscences were in mitral bioprostheses, and all patients presented with valvular regurgitation. Accompanying structural changes (calcification and cuspal tears/perforations), graded semiquantitatively (absent = 0, mild = 1, moderate = 2, and severe = 3), ranged from absent to severe in individual valves. Radiographically detected calcification was greater in CESTD compared with CESAV (CESTD 1.3 ± 0.3 vs. CESAV 0.5 ± 0.3, p < 0.05). Differences in severity of cuspal tears or perforations were not present. Thus, commissural region dehiscence from the stent post of Carpentier-Edwards porcine bioprosthetic valves in the mitral position is a relatively common form of structural deterioration associated with valvular incompetence. It may occur more readily in Carpentier-Edwards supra-annular valves.
