Background: Thrombotic obstruction is an uncommon major fatal complication of the mechanical mitral valve prostheses which is leading very serious clinical results. We assessed the thrombotic occlusion and thromboembolic incidence of five different types of mechanical mitral prostheses that we had used in our clinic.

Methods: Between January 2000 and February 2003, 138 patients recieved bileaflet [(St. Jude (39), Sorin Bicarbon (41), TRI (22)] or monoleaflet [Omnicarbon (17), Bjork-Shiley (19)] mechanical mitral prostheses in Van Yüksek Ihtisas Hospital.

Results: The operative mortality (4.9% versus 5.5%, respectively) and late mortality (7.2% versus 8.8%, respectively) in bileaflet and monoleaflet groups were not significantly different. The incidences of thrombotic occlusion were 5.5%, 0%, 26.3%, 6.2%, 16.6% for St. Jude, Sorin, TRI, Omnicarbon and Bjork-Shiley, respectively. Thrombolytic treatment was given to six patients [Bileaflet (3), Monoleaflet (3)], and urgent re-operation was performed in five patients [Bileaflet (2), Monoleaflet (3)]. The mortality rates of prosthetic valve thrombosis were 2.7%, 0%, 15.7%, 0%, 11.1% for St. Jude, Sorin, TRI, Omnicarbon and Bjork-Shiley, respectively.

Conclusion: This study suggest that the thrombotic and thromboembolic incidence of TRI and Bjork-Shiley prostheses are significantly higher than the other three prostheses for postoperative 1.4 ± 0.6 year period (p < 0.01).

Keywords : Mitral valve replacement, mechanical prostheses, thrombosis, bileaflet, monoleaflet