Bioprosthetic mitral valve thrombosis

An 80-year-old woman presented with an ischaemic stroke one year after an uneventful bioprosthetic mitral valve replacement. Transthoracic echocardiography was of suboptimal image quality; however, Doppler interrogation of the mitral valve revealed a markedly elevated transvalvular gradient (Fig. 1a). Transoesophageal echocardiography showed a large, mobile mass, which was attached to the mitral bioprosthesis and mimicked a ‘thumbs-up sign’ (Fig. 1b; see also Video 1 in the Electronic Supplementary Material). As the patient was afebrile and both blood cultures and ¹⁸FDG PET/CT imaging were negative, bioprosthetic valve thrombosis (BPVT) was considered a more likely diagnosis than endocarditis. Patient was declined for surgery because of the high operative risk. Alternatively, treatment with a warfarin derivate was initiated. Follow-up echocardiography showed a gradual decrease of the echogenic structure size over time (Fig. 1c, d; see also Videos 2 and 3 in the Electronic Supplementary Material), with normalization of the transvalvular gradient.

Fig. 1.

Bioprosthetic valve thrombosis a Elevated transvalvular gradient. b Echogenic mass attached to mitral bioprosthesis. c, d Gradual decrease of echogenic mass under oral anticoagulant therapy

Clinicians should be aware of BPVT, especially in a patient who presents with a thromboembolic event. Prompt echocardiographic evaluation is essential for the diagnosis of BPVT. Symptomatic BPVT is rare, occurring in < 1% of patients undergoing surgical valve implantation. Symptomatic BPVT with a large thrombus (≥ 1.0 cm) requires urgent intervention. In general, surgery is the preferred treatment for symptomatic BPVT. However, fibrinolysis or oral anticoagulants should be considered in high–surgical risk patients.

Conflict of interest

S. Bouwmeester, M. el Farissi and P. Houthuizen declare that they have no competing interests.