Echocardiographic evaluation of anuloplasty rings. Comparison of continuity equation and pressure half-time methods

This study was undertaken to compare pressure half-time and continuity equation methods in the postoperative evaluation of anuloplasty rings. We performed 2-dimensional echocardiography and Doppler studies in 39 patients who had undergone valve repair for mitral regurgitation. In patients with a pressure half-time of 110 msec or more (9/39), there was no significant difference in calculated valve area between the 2 methods (p = 0.696). A significant difference was shown between the 2 methods (p < 0.001) in patients with a half-time less than 110 msec (30/39). When patients were classified according to the type of ring they had received, no significant difference was noted between the 2 groups with regard to peak and mean mitral gradients. In patients placed in subgroups according to half-times of less than 110 msec and half-times of 110 msec or more, no difference was noted between groups in terms of mean mitral gradient, presence of mitral regurgitation, left atrial size, left ventricular function, or heart rate. The continuity equation appears to provide much more homogeneous results in the calculation of valve area in patients who have undergone valvular repair for mitral valve regurgitation.