Objectives. This study sought to determine the applicability of the combined information obtained from transmitral Doppler flow and color M-mode Doppler flow propagation velocities for estimating pulmonary capillary wedge pressure. Background. Although Doppler-derived measurements of left ventricular (LV) filling have been applied to determine left atrial pressure, their accuracy has been limited by the variable effect of ventricular relaxation in these indexes. Recently, flow propagation velocity measured by color M-mode Doppler echocardiography has heen suggested as an index of ventricular relaxation. Methods. We studied 45 patients admitted to the intensive care unit who underwent invasive hemodynamic monitoring. We measured peak early (E) and late (A) transmitral Doppler velocities, E/A ratio and flow propagation velocity (v(p)) and compared them by linear regression with pulmonary capillary wedge pressure (p(w)). Results. We found a modest positive correlation between p(w) and E (r = 0.62, p < 0.001) and the E/A ratio (r = 0.52, p < 0.001) and a negative correlation between p(w) and v(p) (r = -0.34, p = 0.02). By stepwise linear regression, only E and v(p) were statistically significant predictors of p(w). However, the E/v(p) ratio provided the best estimate of p(w) (r = 0.80, p < 0.001; p(w) = 5.27 x [E/v(p)] + 4.6, SEE 3.1 mm Hg). Conclusions. The ratio of component velocity (E) over the color M-mode propagation velocity during early LV filling, by correcting for the effect of LV relaxation, provides a better estimate of p(w) than standard measurements of transmitral Doppler flow.
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