COMMISSURAL REGION DEHISCENCE FROM THE STENT POST OF CARPENTIER-EDWARDS BIOPROSTHETIC CARDIAC VALVES

Structural deterioration is the major reason for reoperation in patien ts with valvular bioprostheses. We present findings on a mode of struc tural deterioration, the pathology of which has not yet been well char acterized. Between January 1990 and December 1992, 39 Carpentier-Edwar ds standard valves (CESTD) and 50 Carpentier-Edwards supra-annular val ves (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 imp lantation 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 wit h 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), grad ed semiquantitatively (absent = 0, mild = 1, moderate = 2, and severe = 3), ranged from absent to severe in individual valves. Radiographica lly detected calcification was greater in CESTD compared with CESAV (C ESTD 1.3 +/- 0.3 vs. CESAV 0.5 +/- 0.3, p < 0.05). Differences in seve rity of cuspal tears or perforations were not present. Thus, commissur al region dehiscence from the stent post of Carpentier-Edwards porcine bioprosthetic valves in the mitral position is a relatively common fo rm of structural deterioration associated with valvular incompetence. It may occur more readily in Carpentier-Edwards supra-annular valves.