Mean platelet volume in functional and thrombotic prosthetic mitral valve.

The mean platelet volume (MPV) values reflect platelet size and are accepted as marker of platelet activation. We sought to test the hypothesis that platelet activation occurs independently from presence or absence of thrombus in prosthetic mitral valve. A total of 168 patients were included in the study. Study participants were divided in three groups: group 1 (n = 62) - patients with normal prosthetic mitral valve; group 2 (n = 37) - patients with prosthetic mitral valve thrombosis; and group 3 (n = 69) - healthy individuals. MPV values were significantly higher in normal and thrombotic prosthetic mitral valve patients than in healthy individuals (P = 0.008 and P = 0.01, respectively). MPV values were not different between normal prosthetic mitral valve and thrombotic prosthetic mitral valve. This is the first study indicating that increased MPV is present in normal and thrombotic prosthetic mitral valve, implying that platelet reactivity occurs in prosthetic mitral valve irrespective of development of thrombus formation.