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Strut fracture of a Bjork-Shiley mitral valve prosthesis.

Use of mechanical prostheses for direct surgical replacement of cardiac valves was originally proposed in 1953 by Hufnagel [1]. Sixteen years later, Bjork introduced the nowfamous valvular prosthesis that bears his name. Throughout the world, to date, more than 80,000 Bjork-Shiley valves have been implanted [2, 31. As beneficial as these valves have been, their use is not without a potential for the development of severe, life-threatening complications. Mechanical failure has been described either when one of the valve struts fractures (with resultant embolization of the disk) or when fibrotic material encroaches upon the valve seat, precluding complete opening or closure of the disk [2, 4]. As the prevalence of valve prostheses has increased, so have the number of reported prosthetic failures. The radiographic literature has largely ignored the signs of prosthetic valvular malfunction. To draw attention to this problem, and in the hope that doing so will increase survival rates, we report a case of acute dysfunction of a prosthetic mitral valve due to fracture of the valve’s strut with embolization of the disk.