Sun J P, Pu M, Fouad F M, Christian R, Stewart W J, Thomas J D
Department of Cardiology, Cleveland (Ohio) Clinic Foundation 44195, USA.
Circulation. 1997 Feb 18;95(4):932-9. doi: 10.1161/01.cir.95.4.932.
A new Doppler echocardiographic technique has been developed for automated cardiac output measurement (ACOM) that assumes neither a flat flow profile nor collinearity with the scan line, but clinical validation of this method is lacking.
In 165 subjects (50 intensive care patients, 10 dobutamine echocardiography patients, and 105 normal volunteers; age, 49.4 +/- 19.3 years; 92 men), ACOM was performed in the left ventricular outflow tract (LVOT), with the color baseline shifted to avoid aliasing. ACOM was also tested in a pulsatile in vitro model. Stroke volume was calculated by double integration of Doppler signals in space (across the LVOT) and in time (through the systolic period), assuming hemiaxial symmetry: integral of integral of pi r v(r,t) dr dt, where v(r,t) is the velocity at a distance r from the center of the LVOT at time t during systole. Stroke volume from ACOM was compared with thermodilution (TD), aortic valve pulsed-wave Doppler (PWAO), and left ventricular echocardiographic (two-dimensional [2D]) methods. There was good correlation between ACOM and PWAO (r = .93). TD (r = .86), and 2D (r = .74), with close agreement seen. ACOM had higher correlation and agreement with TD than did either PWAO (P < .02) or 2D (P < .01). ACOM was also able to track accurately the changes in cardiac output with dobutamine infusion in comparison with PWAO (r = .94). In vitro assessment demonstrated excellent correlation (r = .98, y = 1.0x + 1.94) with little impact of pulse repetition frequency or misalignment up to 30 degrees. Gain dependency was noted but could be optimized by visual inspection of the color image.
Automatic integration of numerical data within color Doppler flow fields is a feasible new method for quantifying flow. It is simpler and faster, requires fewer assumptions, and uses only one apical view. ACOM is a promising new approach to echocardiographic quantification that deserves further study and refinement.
已开发出一种新的多普勒超声心动图技术用于自动心输出量测量（ACOM），该技术既不假定血流剖面为扁平状，也不要求与扫描线共线，但缺乏该方法的临床验证。
对165名受试者（50名重症监护患者、10名多巴酚丁胺超声心动图检查患者和105名正常志愿者；年龄49.4±19.3岁；92名男性）在左心室流出道（LVOT）进行ACOM，将彩色基线移位以避免混叠。还在搏动性体外模型中对ACOM进行了测试。通过对多普勒信号在空间（穿过LVOT）和时间（整个收缩期）上进行双重积分来计算每搏输出量，假设为半轴对称：πr v(r,t) dr dt的积分，其中v(r,t)是收缩期t时刻距离LVOT中心r处的速度。将ACOM得出的每搏输出量与热稀释法（TD）、主动脉瓣脉冲波多普勒法（PWAO）和左心室超声心动图（二维[2D]）方法进行比较。ACOM与PWAO（r = 0.93）、TD（r = 0.86）和2D（r = 0.74）之间具有良好的相关性，且一致性良好。与PWAO（P < 0.02）或2D（P < 0.01）相比，ACOM与TD的相关性和一致性更高。与PWAO相比（r = 0.94），ACOM还能够准确跟踪多巴酚丁胺输注时的心输出量变化。体外评估显示具有极佳的相关性（r = 0.98，y = 1.0x + 1.94），脉冲重复频率或高达30度的未对准影响很小。注意到增益依赖性，但可通过对彩色图像进行视觉检查来优化。
彩色多普勒流场内数值数据的自动积分是一种可行的新的流量量化方法。它更简单、更快，所需假设更少，且仅使用一个心尖视图。ACOM是一种有前景的超声心动图量化新方法，值得进一步研究和完善。
