Xie G Y, Berk M R, Smith M D, DeMaria A N
Division of Cardiology, University of Kentucky, Lexington.
J Am Coll Cardiol. 1994 Oct;24(4):1041-5. doi: 10.1016/0735-1097(94)90867-2.
This study attempted to develop and validate a simple method for calculating aortic regurgitant fraction by use of pulsed wave Doppler echocardiography.
Although several investigators have been able to determine aortic regurgitant fraction by Doppler echocardiography, the methods used require accurate determination of the cross-sectional areas of intracardiac sites at which the volumetric flow is calculated.
Our concept was based on a constant relation that exists between the cross-sectional area of the left ventricular outflow tract and the mitral valve annulus in normal subjects. To verify this, we used Doppler echocardiography to measure the flow velocity integral of the left ventricular outflow tract and the mitral annulus in the apical view in 50 normal subjects (32 men, 18 women, mean age 34 years).
Close correlation (r = 0.95) was observed between the flow velocity integral (FVI) of the outflow tract (OT) and that of the mitral annulus (MA): FVIMA/FVIOT = 0.77. Because mitral flow equals aortic flow in normal subjects, the ratio of the cross-sectional area of the mitral annulus to that of the outflow tract was 1/0.77. In patients with aortic regurgitation, the regurgitant fraction (RF) = (Aortic flow-Mitral flow)/Aortic flow = 1-Mitral flow/Aortic flow. Substituting 0.77 for the area component of flow, RF = 1-(1/0.77).(FVIMA/FVIOT). To evaluate the accuracy of this method, we compared the regurgitant fraction derived by Doppler echocardiography with that from catheterization findings in 20 patients with aortic regurgitation (an isolated lesion was found in 14). The regurgitant fraction by catheterization was the difference between total (angiographic) and forward (thermodilution) stroke volumes as a percent of total flow. Good correlation was observed between catheterization and Doppler regurgitant fraction (r = 0.88, SEE 9%, p < 0.01).
Thus, regurgitant fraction can be estimated from Doppler echocardiography in patients with aortic regurgitation by a method that requires only measurements of the flow velocity integral from the mitral annulus and left ventricular outflow tract.
本研究试图开发并验证一种利用脉冲波多普勒超声心动图计算主动脉反流分数的简单方法。
尽管一些研究人员已能够通过多普勒超声心动图确定主动脉反流分数，但所使用的方法需要准确测定计算容积流量时的心内部位的横截面积。
我们的概念基于正常受试者左心室流出道横截面积与二尖瓣环横截面积之间存在的恒定关系。为了验证这一点，我们使用多普勒超声心动图在50名正常受试者（32名男性，18名女性，平均年龄34岁）的心尖视图中测量左心室流出道和二尖瓣环的流速积分。
观察到流出道（OT）的流速积分（FVI）与二尖瓣环（MA）的流速积分之间存在密切相关性（r = 0.95）：FVIMA/FVIOT = 0.77。由于正常受试者中二尖瓣血流等于主动脉血流，二尖瓣环横截面积与流出道横截面积之比为1/0.77。在主动脉反流患者中，反流分数（RF）=（主动脉血流 - 二尖瓣血流）/主动脉血流 = 1 - 二尖瓣血流/主动脉血流。用0.77代替血流的面积成分，RF = 1 - （1/0.77）·（FVIMA/FVIOT）。为了评估该方法的准确性，我们将20例主动脉反流患者（14例发现为孤立病变）通过多普勒超声心动图得出的反流分数与导管检查结果得出的反流分数进行了比较。导管检查得出的反流分数是总（血管造影）和前向（热稀释）搏出量之差占总流量的百分比。观察到导管检查和多普勒反流分数之间存在良好相关性（r = 0.88，标准误9%，p < 0.01）。
因此，对于主动脉反流患者，可以通过一种仅需测量二尖瓣环和左心室流出道流速积分的方法，从多普勒超声心动图估计反流分数。
