采用血流会聚区法评估二尖瓣狭窄患者的二尖瓣面积：取样容积速度的选择

Estimation of mitral valve area in patients with mitral stenosis by the flow convergence region method: selection of aliasing velocity.

作者信息

Deng Y B, Matsumoto M, Wang X F, Liu L, Takizawa S, Takekoshi N, Shimizu T, Mishima K

机构信息

Kanazawa Medical University, Ishikawa-ken, Japan.

出版信息

J Am Coll Cardiol. 1994 Sep;24(3):683-9. doi: 10.1016/0735-1097(94)90015-9.

DOI:10.1016/0735-1097(94)90015-9

PMID:8077539

Abstract

OBJECTIVES

We attempted to determine the most suitable aliasing velocity for applying the hemispheric flow convergence equation to calculate the mitral valve area in mitral stenosis using a continuity equation.

BACKGROUND

The flow convergence region method has been used for calculating mitral valve area in patients with mitral stenosis. However, the effect of varying aliasing velocity on the accuracy of this method has not been investigated fully.

METHODS

We studied 42 patients with mitral stenosis using imaging and Doppler echocardiography. Aliasing velocities of 17, 21, 28, 34, 40 and 45 cm/s were used. The transmitral maximal flow rate (Q [ml/s]) was calculated using the hemispheric flow convergence equation Q = 2 x pi x R2 x AV x alpha/180, where R (cm) is the maximal radius of the flow convergence region, AV is the aliasing velocity, and alpha/180 is a factor accounting for the inflow angle (alpha). Mitral valve area (A [cm2]) was calculated according to the continuity equation A = Q/V, where V (cm/s) is the peak transmitral velocity by the continuous wave Doppler method.

RESULTS

Mitral valve area was progressively underestimated with increasing aliasing velocity. The actual and percent differences noted between the mitral valve area by the flow convergence region method and that by two-dimensional echocardiographic planimetry were -0.06 +/- 0.23 cm2 (mean +/- SD) and 0.09 +/- 15.7% at an aliasing velocity of 21 cm/s, increasing gradually with increasing aliasing velocity, and were -1.24 +/- 0.9 cm2 and -72.56 +/- 16.4% at an aliasing velocity of 45 cm/s. Mitral valve areas estimated by the flow convergence region method at an aliasing velocity of 21 cm/s in 11 patients with associated > 2+ mitral regurgitation (2.12 +/- 1.17 cm2) and 8 with associated > 2+ aortic regurgitation (1.28 +/- 0.71 cm2) were not significantly different using planimetry (2.24 +/- 1.39 cm2, p > 0.05 and 1.27 +/- 0.74 cm2, p > 0.05, respectively) but were significantly different by the pressure half-time method (1.59 +/- 1.12 cm2, p < 0.001 and 1.63 +/- 0.93 cm2, p < 0.01, respectively).

CONCLUSIONS

This study indicated the most appropriate aliasing velocity for the accurate estimation of mitral valve area in patients with mitral stenosis.

摘要

目的

我们试图确定在使用连续性方程通过半球形血流会聚方程计算二尖瓣狭窄患者的二尖瓣面积时，最合适的取样容积速度。

背景

血流会聚区法已用于计算二尖瓣狭窄患者的二尖瓣面积。然而，不同取样容积速度对该方法准确性的影响尚未得到充分研究。

方法

我们使用成像和多普勒超声心动图对42例二尖瓣狭窄患者进行了研究。使用的取样容积速度分别为17、21、28、34、40和45cm/s。通过半球形血流会聚方程Q = 2×π×R²×AV×α/180计算二尖瓣最大流速（Q [ml/s]），其中R（cm）是血流会聚区的最大半径，AV是取样容积速度，α/180是一个考虑流入角度（α）的因子。根据连续性方程A = Q/V计算二尖瓣面积（A [cm²]），其中V（cm/s）是连续波多普勒法测得的二尖瓣峰值流速。

结果

随着取样容积速度的增加，二尖瓣面积逐渐被低估。在取样容积速度为21cm/s时，血流会聚区法测得的二尖瓣面积与二维超声心动图平面测量法测得的二尖瓣面积之间的实际差值和百分比差值分别为-0.06±0.23cm²（平均值±标准差）和0.09±15.7%，并随着取样容积速度的增加而逐渐增大；在取样容积速度为45cm/s时，差值分别为-1.24±0.9cm²和-72.56±16.4%。在11例伴有中重度二尖瓣反流（2.12±1.17cm²）和8例伴有中重度主动脉反流（1.28±0.71cm²）的患者中，取样容积速度为21cm/s时，血流会聚区法估算的二尖瓣面积与平面测量法（分别为2.24±1.39cm²，p>0.05和1.27±0.74cm²，p>0.05）无显著差异，但与压力减半时间法（分别为1.59±1.12cm²，p<0.001和1.63±0.93cm²，p<0.01）有显著差异。