Pulsatile flow computational simulations of mitral regurgitation.

The noninvasive quantification of mitral regurgitation remains an important clinical goal. Recently, the flow convergence method was developed to estimate the regurgitant flow rate. This study used three-dimensional pulsatile flow computational simulations to evaluate the accuracy of the flow convergence method in the presence of complicating factors such as ventricular confinement, noncircular orifice shape, and the presence of aortic outflow. Results showed that in the absence of aortic outflow and ventricular confinement, there was a plateau zone where the calculated flow rate by the hemispheric formula approximated the true flow rate, independent of the orifice shape. In the presence of aortic outflow and in chambers of physiologic dimensions, there was no longer a clear zone where the hemispheric formula was valid. The hemi-elliptic modification of the flow convergence method worked in all cases, independent of the degree of ventricular confinement or the presence of aortic outflow. Therefore, application of the hemi-elliptic formula should be considered in future clinical studies.