Limitation of echocardiographic indexes for the accurate estimation of left ventricular relaxation and filling pressure: Interim results of SMAP, a multicenter study in Japan

Purpose : Mitral annular early-diastolic velocityi (eʹ) and the early transmitral velocity to eʹ ratio (E/eʹ) have been widely used as indexes of left ventricular (LV) relaxation and filling pressure, respectively. There are, however, a number of clinical settings in which eʹ and E/eʹ may not be reliable. We thus conducted a multicenter study in Japan (SMAP) to determine the accuracy of echocardiographic indexes of LV relaxation and filling pressure. Subjects and Methods : In 52 patients with various structural heart diseases from four institutions, time constant of LV pressure decay (τ) and LV mean diastolic pressure (LVMDP) were measured using a micromanometer-tipped catheter. Echocardiographic diastolic parameters were also measured. Results and Discussion : There was no difference in eʹ between patients with and without abnormal relaxation. There was a weak, but significant, correlation between τ (48 ± 11 msec) and eʹ (r=-0.30, p= 0. 03), or deceleration time of pulmonary venous D wave (r=0. 40, p= 0.02). There was no difference in E/eʹ between patients with and without elevated LV filling pressure. LVMDP (8. 3ʹ6. 1 mmHg) signifi cantly correlated with transmitral E/A (r=0. 47, p=0. 001), but not with E/eʹ (r=0. 27, p=0. 053). Conclusion: The multicenter study in Japan demonstrated that eʹ and E/eʹ might be of limited use for estimating LV relaxation and filling pressure in patients with various structural heart diseases. Furthermore, eʹ and E/eʹ were not superior to the conventional indexes of LV inflow or pulmonary venous flow.