Application of Doppler color flow imaging to determine valve area in mitral stenosis

This study was undertaken to examine whether Doppler color flow imaging could accurately estimate the valve area in mitral stenosis. Doppler color flow assessments were performed in both an in vitro model and in 30 patients with mitral stenosis undergoing cardiac catheterization. In the experimental Doppler study using a circuit model, color jet width correlated well with actual orifice diameter (r = 0.99). In the clinical Doppler study, the mitral valve orifice was assumed to be elliptic and the mitral valve area was calculated from the following equation: (π/4)(a × b), where a = color jet width at the mitral valve orifice in the apical long-axis view (short diameter) and b = the width in the 90° rotated view (long diameter). Mitral valve area was also determined by two-dimensional echocardiography and the pressure half-time method, and the results for all three noninvasive methods were compared with those obtained at cardiac catheterization.By Doppler color flow imaging, mitral valve area could be determined in all patients and there was a significant correlation between the Doppler jet and catheterization estimates of mitral valve area (r = 0.93). Valve area determined by two-dimensional echocardiography correlated well with catheterization measurements in 26 patients (r = 0.84). However, the area could not be determined in 4 (13%) of the 30 patients because of technical problems. Although there was a fair correlation between the valve area determined by the pressure half-time method and catheterization (r = 0.79), this method tended to overestimate valve area in patients with aortic regurgitation.These findings suggest that Doppler color flow imaging can provide an accurate estimate of mitral valve area and appears to be potentially applicable to the assessment of the severity of mitral stenosis