[A case of minor strut fracture of Björk-Shiley Convexo-concave valve and a case of elective prophylactic reoperation].

We reported 2 cases of previous valve replacement with Björk-Shiley Convexo-concave (C-C) valve prosthesis. A 43-year-old male who had undergone mitral valve replacement with 27 mm C-C valve was admitted with severe dyspnea. Although intensive medical treatment was initiated, he died 18 hours after admission. An autopsy revealed minor strut fracture of C-C valve. An electron minor strut fracture of C-C valve. An electron microscopic examination of the explanted valve revealed destruction of minor strut. A 52-year-old female who had underwent aortic valve replacement with 21 mm C-C valve 10 years previously had elective prophylactic reoperation. The postoperative course was uneventful. An electron microscopic examination of the minor strut revealed small linear strain which may cause fatigue defects.