A morphologic study of Carpentier-Edwards pericardial xenografts in the mitral position exhibiting primary tissue failure in adults in comparison with Ionescu-Shiley pericardial xenografts

Objective: We sought to investigate the durability and mechanism of the Car pentier-Edwards pericardial xenograft in the mitral position in comparison with that of the Ionescu-Shiley pericardial xenograft. Methods: A total of 284 patients who received the Ionescu-Shiley pericardia l xenograft in the mitral position between 1980 and 1984 and 84 patients wh o received the Carpentier-Edwards pericardial xenograft in the mitral posit ion between 1984 and 1999 were included in the study. The freedom from reop eration rates for both graft types were determined. For morphologic study, the pathologic findings of 23 valves of 123 explanted Ionescu-Shiley perica rdial xenografts with structural valve deterioration, nonstructural valve d eterioration, or both were determined and compared with those of 20 explant ed Carpentier-Edwards pericardial xenografts with structural valve deterior ation, nonstructural valve deterioration, or both. Each pathologic finding was graded and assigned a Score. Both types were matched for age at reopera tion (50-75 years) and duration of valve function (8-11 years). Results: Freedom from reoperation caused by structural valve deterioration, nonstructural valve deterioration, or both was significantly better for Ca rpentier-Edwards pericardial xenografts than for Ionescu-Shiley pericardial xenografts at 8 years after the operation (Carpentier-Edwards pericardial xenografts: 91.3% vs Ionescu-Shiley pericardial xenografts: 71.9%, P =.0061 ), but it was similar for both types at 12 years (Carpentier-Edwards perica rdial xenografts: 43.6% vs Ionescu-Shiley pericardial xenografts: 43.6%, P =.2865). No severe leaflet tears were seen among Carpentier-Edwards pericar dial xenografts. The mean area percentage of tissue overgrowth was 15.3% in Carpentier-Edwards pericardial xenografts and 3.4% in Ionescu-Shiley peric ardial xenografts (P =.0001). The mean calcification area percentage was 13 .6% in Carpentier-Edwards pericardial xenografts and 31.5% in Ionescu-Shile y pericardial xenografts (P =.0001). Conclusions: Tissue overgrowth on the atrial surface, ventricular surface, or both was the cause of structural valve deterioration, nonstructural valv e deterioration, or both of Carpentier-Edwards pericardial xenografts in ad ults. This was different from Ionescu-Shiley pericardial xenograft failure, which resulted from severe calcification and leaflet tears. Organized thro mbi on cusps, in addition to valve design, may have contributed to such tis sue overgrowth on Carpentier-Edwards pericardial xenografts.