Influence of aortic regurgitation on the assessment of the pressure half-time and derived mitral-valve area in patients with mitral stenosis

The influence of aortic regurgitation on the Doppler assessment of pressure half-time (T1/2) and on the derived calculation of the mitral-valve area has not yet been adequately evaluated in patients with mitral stenosis and associated aortic regurgitation. Therefore this study was undertaken to verify the accuracy of the T1/2 method for the noninvasive estimation of mitral-valve area in patients with mitral stenosis and associated aortic regurgitation. Data were obtained from 31 selected patients who underwent cardiac catheterization within 24 h of the noninvasive examination. From the Doppler velocity curve, T1/2 was calculated as the interval between the peak transmitral velocity and velocity/ square root of 2. Mitral-valve area was measured from the T1/2 with a computerized system using the equation: 220/T1/2, in cm2. Calculation of the mitral-valve area at catheterization was derived applying the modified Gorlin formula. Mean mitral-valve area, as determined at catheterization, ranged from 0.5 to 2.8 cm2 (1.3 +/- 0.6). Mean mitral-valve area, as calculated by continuous-wave Doppler, ranged from 0.7 to 2.7 cm2 (1.5 +/- 0.6). Linear-regression analysis of data revealed a good correlation between Gorlin and Doppler measurements of the mitral-valve area (r = 0.90, SEE = 0.28 cm2, P less than 0.001, y = 1.0x + 0.2). Doppler showed a systematic overestimate of the mitral-valve area (26%) in patients with mitral stenosis and aortic regurgitation as compared to the Gorlin formula. The overestimate of continuous-wave Doppler was even greater (39%) in a subgroup of patients with 2+ or 3+ angiographic aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)