Noncalcific cusp thickening in Ionescu-Shiley cardiac valvular bioprostheses

This study was undertaken to examine the morphological basis for noncalcific cusp thickening in 20 standard-profile Ionescu-Shiley bovine pericardial cardiac valvular bioprostheses (16 aortic, four mitral) with primary valve failure due to cusp tears. The patients included 17 males and three females, with a mean age of 52.0 years; their valves had been implanted for a mean of 105.8 months. All cases had variable degrees of "plasma insudation" without correlation to identifiable patient parameters. This was accentuated in individual valves in the cusp with the most extensive tears. In addition, the three valves with the thickest cusps were grossly distorted by massive deposits of amyloid (identified as AL-amyloid in two index cases studied). Two other valves had incidental amyloid deposits, identifiable only by electron microscopy. Amyloid involvement of pericardial bioprostheses has not been previously reported. The literature pertaining to amyloid involvement and plasma insudation of bioprostheses is reviewed.