Shiota T, Jones M, Yamada I, Heinrich R S, Ishii M, Sinclair B, Holcomb S, Yoganathan A P, Sahn D J
Oregon Health Sciences University, Portland, USA.
Circulation. 1996 Feb 1;93(3):594-602. doi: 10.1161/01.cir.93.3.594.
The aim of the present study was to evaluate dynamic changes in aortic regurgitant (AR) orifice area with the use of calibrated electromagnetic (EM) flowmeters and to validate a color Doppler flow convergence (FC) method for evaluating effective AR orifice area and regurgitant volume.
In 6 sheep, 8 to 20 weeks after surgically induced AR, 22 hemodynamically different states were studied. Instantaneous regurgitant flow rates were obtained by aortic and pulmonary EM flowmeters balanced against each other. Instantaneous AR orifice areas were determined by dividing these actual AR flow rates by the corresponding continuous wave velocities (over 25 to 40 points during each diastole) matched for each steady state. Echo studies were performed to obtain maximal aliasing distances of the FC in a low range (0.20 to 0.32 m/s) and a high range (0.70 to 0.89 m/s) of aliasing velocities; the corresponding maximal AR flow rates were calculated using the hemispheric flow convergence assumption for the FC isovelocity surface. AR orifice areas were derived by dividing the maximal flow rates by the maximal continuous wave Doppler velocities. AR orifice sizes obtained with the use of EM flowmeters showed little change during diastole. Maximal and time-averaged AR orifice areas during diastole obtained by EM flowmeters ranged from 0.06 to 0.44 cm2 (mean, 0.24 +/- 0.11 cm2) and from 0.05 to 0.43 cm2 (mean, 0.21 +/- 0.06 cm2), respectively. Maximal AR orifice areas by FC using low aliasing velocities overestimated reference EM orifice areas; however, at high AV, FC predicted the reference areas more reliably (0.25 +/- 0.16 cm2, r = .82, difference = 0.04 +/- 0.07 cm2). The product of the maximal orifice area obtained by the FC method using high AV and the velocity time integral of the regurgitant orifice velocity showed good agreement with regurgitant volumes per beat (r = .81, difference = 0.9 +/- 7.9 mL/beat).
This study, using strictly quantified AR volume, demonstrated little change in AR orifice size during diastole. When high aliasing velocities are chosen, the FC method can be useful for determining effective AR orifice size and regurgitant volume.
本研究的目的是使用校准的电磁流量计评估主动脉反流（AR）瓣口面积的动态变化，并验证彩色多普勒血流会聚（FC）法评估有效AR瓣口面积和反流容积的准确性。
对6只绵羊进行手术诱导AR，术后8至20周，研究了22种血流动力学不同的状态。通过相互平衡的主动脉和肺动脉电磁流量计获得瞬时反流流速。通过将这些实际AR流速除以每个稳态匹配的相应连续波速度（每个舒张期25至40个点）来确定瞬时AR瓣口面积。进行超声心动图研究，以获得低范围（0.20至0.32 m/s）和高范围（0.70至0.89 m/s）的FC最大混叠距离；使用半球形血流会聚假设对FC等速表面计算相应的最大AR流速。通过将最大流速除以最大连续波多普勒速度得出AR瓣口面积。使用电磁流量计获得的AR瓣口大小在舒张期变化很小。电磁流量计在舒张期获得的最大和时间平均AR瓣口面积分别为0.06至0.44 cm²（平均，0.24±0.11 cm²）和0.05至0.43 cm²（平均，0.21±0.06 cm²）。使用低混叠速度的FC法得出的最大AR瓣口面积高估了参考电磁瓣口面积；然而，在高混叠速度下，FC法对参考面积的预测更可靠（0.25±0.16 cm²，r = 0.82，差异 = 0.04±0.07 cm²）。使用高混叠速度的FC法获得的最大瓣口面积与反流瓣口速度的速度时间积分的乘积与每搏反流容积显示出良好的一致性（r = 0.81，差异 = 0.9±7.9 mL/搏）。
本研究使用严格量化的AR容积，证明舒张期AR瓣口大小变化很小。当选择高混叠速度时，FC法可用于确定有效AR瓣口大小和反流容积。
