| Abstract: |
SUMMARY, CONCLUSION & RECOMMENDATIONSIn developing countries, rheumatic fever, a sequel of group A streptococcal upper respiratory tract infection, is responsible for almost half of cardiovascular disease in all age groups, and is leading cause of death in the 1st five decades of life. Mitral valve disease is the most common rheumatic valve disease.Mitral valve repair is the procedure of choice to treat mitral valve dysfunction of all etiologies. Advantages of mitral valve repair over mitral valve replacement include improved long-term survival, better preservation of left ventricular function, and greater freedom from endocarditis, thromboembolism, and anticoagulant-related hemorrhage. With the introduction of standardized surgical techniques by Carpentier, Duran, and others, mitral valve repair has become reproducible and widely disseminated.When mitral valve repair is not feasible, mitral valve replacement will be the only choice. The bileaflet model is almost with streamline flow, this feature emerged it as today’s prosthesis of preference in many centers, despite its higher coast. We tried in this study to not only to get the best prosthetic valve design but also to get the best orientation of this valve to obtain its best performance.We selected a hundred patients who needed mitral valve replacement and evaluated them clinically and echocardiographically preoperatively. The patients underwent mitral valve replacement where 50 patients of them received the bileaflet metallic mitral valve (St. Jude, 29 mm) in anatomical orientation while the other 50 patients received the same valve in antianatomical orientation with posterior leaflet preservation for all cases.The intraoperative data were collected for both groups in the form of cross clamp time, total by pass time and need for inotrops and vasodilators. There was no significant difference between the intraoperative data of both groups.The ICU stay of both groups showed no significant difference between both groups including the ventilation period, inotropes, vasodilators and incidence of complications.Three months later after patients discharge echocardiography was performed for all patients of both groups during rest and during stress by using dobutamine to get our target which is the double of cardiac index. The echocardiographic data included the left ventricular function in the form of ejection fraction, cardiac output and cardiac index, the hemodynamic performance of the prosthetic valve was studied in the form of maximum and mean gradient across the valve and the effective orifice area of the valve during rest and exercise. These collected echo data demonstrated that there is no significant difference between both groups of different orientations.Conclusions and Recommendations.The hemodynamic performance of the mitral prosthetic bileaflet metallic valve in anatomical and antianatomical orientations is not significantly different. The implantation of the bileaflet valve should consider the subvalvular apparatus and its relation to the mechanical valve leaflet free motion irrelevant to the valve orientation either in anatomical or antianatomical orientation.We recommend that the study should be done on different types and different sizes of the bileaflet prosthetic valves to compare there hemodynamic performance in different orientations. The follow up period should be considered to be longer to detect any change in the hemodynamic performance of the valves with time and correlate it to there orientations.
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