Calculation of mitral regurgitant orifice area with use of a simplified proximal convergence method: Initial clinical application

To validate a previously proposed simplified proximal flow convergence method for calculating mitral regurgitant orifice area (ROA), a prospective study was conducted in ambulatory patients and in patients undergoing open heart surgery. Assuming a pressure difference between the left ventricle and left atrium of approximately 100 mm Hg (jet velocity [vp] 500 cm/s) and setting the color aliasing velocity (va) to 40 cm/s, we simplified the conventional proximal convergence method formula (ROA = 2πr2va/vp) to r2/2, where r is the radius of the proximal convergence isovelocity hemisphere. For 57 ambulatory patients with a wide range of mitral regurgitant severity (1 to 4+), ROA was calculated by the conventional (x) and simplified (y) methods, demonstrating excellent accuracy (r = 0.92; P