Mitral valve replacement the bottom of the heart through a tube inserted in a small incision in the patient’s chest. The physician uses the tube to deploy the valve and positions it so that it rests over the heart's existing mitral valve. It is then anchored securely in place by an adjustable tether. The valve is fully retrievable, totally repositionable and is sewn onto a Nitinol frame. Nitinol is a superelastic nickel and titanium "shape memory alloy" whose flexibility eases implantation, but regains its original shape when it returns to a patient’s normal body temperature. The transition of TMVR from concept to reality
Mitral insufficiency during a cardiac cycle. Methods that have been used to assess the regurgitant fraction in mitral regurgitation include echocardiography, cardiac catheterization, fast CT scan, and cardiac MRI. The echocardiographic technique to measure the regurgitant fraction is to determine the forward flow through the mitral valve (from the left atrium to the left ventricle) during ventricular diastole, and comparing it with the flow out of the left ventricle through the aortic valve in ventricular systole. This method assumes that the aortic valve does not suffer from aortic insufficiency. Another way to quantify the degree of MR is to determine the area