Valve failure caused by cusp tears in low-profile Ionescu-Shiley bovine pericardial bioprosthetic valves.

The pathologic findings in two low-profile Ionescu-Shiley bioprostheses that failed because of cusp tears are presented. Both valves were in the mitral position, one in place 28 months and the other 40 months. Observation of the valves and their tears suggests that stress at the cusp alignment stitches may be important in the genesis of the tears.