A novel approach to calculation of mean mitral valve gradient by doppler echocardiography

The Doppler-derived mean mitral valve gradient (APM) based on the simplified Bernoulli equation requires computerized integration of the Doppler signal and evaluation by a technician with the use of special equipment. We have noted empirically that the APM can be derived by the equation ΔP M = (P p - P T ) / 3 + P T . Peak (P P ) and trough (PT) pressures are derived from the simplified Bernoulli equation (P = 4V 2 ). This equation can be used by the experienced observer to calculate the mean mitral valve gradient without specialized equipment. The purpose of this study is to validate the above empirically derived equation in patients with mitral stenosis. We retrospectively reviewed 41 consecutive studies done at our institution from October 1, 1997, through September 30, 1998, in which mean mitral valve gradient was assessed. Each study was reviewed and the ΔP M , P P , and P T were measured for 3 beats by using the software package on an HP Sonos 2500. AP, was also calculated with our formula. A linear regression model was used to compare the results of the measured versus the calculated ΔP M . The following sub-categories were also evaluated: transthoracic studies (TTE), transesophageal studies (TEE), native valve gradients (NV), prosthetic valve gradients (PV), sinus rhythm (SR), and atrial fibrillation (AF). The results of the regression analysis of the entire population of mean versus calculated APM are n=41, r = 0.99, P r = 0.99, P r = 0.99, P r = 0.99, P r = 0.98, P r = 0.99, P r = 0.98, P