[Intermittent opening and flow of a mitral valve prosthesis caused by acute and chronic thrombosis].

The case report concerns a female with intermittent opening and flow of Bjork mitral prosthesis demonstrated by echo-doppler. Dyspnoea and rapidly worsening heart failure were also present. Anatomic confirmation during cardiac surgery showed a fresh thrombus over old one. Principal instrumental criteria of prosthesis thrombosis are finally reported.