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 of the regurgitant flow at the level of the valve. This is known as the regurgitant orifice area, and correlates with the size of the defect in the mitral valve. One particular echocardiographic technique used to measure the orifice area is measurement of the proximal isovelocity surface area (PISA). The flaw of using PISA to determine the mitral valve regurgitant orifice area is that it measures the flow at one moment in time in the cardiac cycle, which may not reflect the average performance of the regurgitant jet. The treatment of mitral insufficiency depends on the acuteness of the disease