Badano L, Cassottano P, Bertoli D, Carratino L, Lucatti A, Spirito P
Servizio di Cordiologia, Ospedale di Neiv, Genoa, Italy.
Am J Cardiol. 1996 Nov 1;78(9):1023-8. doi: 10.1016/s0002-9149(96)00528-0.
Measurements of valve orifice area in aortic stenosis are based on the assumption that orifice area remains constant throughout ejection and is independent of transvalvular gradients and flow. Recent studies, however, have suggested that the calculated valve area of calcific aortic stenosis may change in different flow conditions. Therefore, we tested the hypothesis that in vivo effective orifice area of a stenotic aortic valve changes continuously during ejection, which would make a single area measurement a potentially inadequate indicator of the severity of the stenosis. Doppler measurements of flow velocity in the ascending aorta and in the left ventricular outflow tract at peak velocity, at half-peak velocity during acceleration (midacceleration), and at half-peak velocity during deceleration (mid-deceleration) were obtained in 26 patients with aortic stenosis (mean gradient 50 +/- 19 mm Hg and effective aortic orifice are 0.7 +/- 0.3 dcm2) and in 14 normal subjects of similar age and gender, to calculate instantaneous effective aortic orifice area at midacceleration, at peak velocity and at mid-deceleration. In the 26 patients with aortic stenosis, aortic valve area at midacceleration was 84 +/- 15% of valve area at peak velocity (p < 0.0001), and valve area at mid-deceleration was 113 +/- 17% of that measured at peak velocity (p < 0.01). Conversely, in normal subjects, aortic valve area remained constant during ejection and was 97 +/- 5% and 99 +/- 6% of valve area at peak velocity, respectively, at midacceleration and mid-deceleration (p > 0.05). In addition, in patients with aortic stenosis the percentage of change in effective aortic valve area from midacceleration to mid-deceleration varied widely, from -17% to +49% (mean change +26 +/- 14%). There was no relation between percentage of change in effective valve area and mean transaortic gradient (r = 0.05; p = 0.30) or effective valve area at peak velocity (r = -0.11; p = 0.14). Our results indicate that effective aortic valve area continues to change during ejection in patients with aortic stenosis, and that the magnitude of this change is independent of the usual indexes of severity of the stenosis. Conversely, effective aortic valve area remains constant during ejection in normal subjects.
主动脉瓣狭窄时瓣膜口面积的测量基于这样一个假设，即整个射血过程中瓣膜口面积保持恒定，且与跨瓣膜压力阶差和血流无关。然而，最近的研究表明，钙化性主动脉瓣狭窄的计算瓣膜面积在不同血流状态下可能会发生变化。因此，我们检验了这样一个假设，即狭窄主动脉瓣的体内有效瓣口面积在射血过程中持续变化，这会使单次面积测量可能不足以作为狭窄严重程度的指标。对26例主动脉瓣狭窄患者（平均压力阶差50±19 mmHg，有效主动脉瓣口面积0.7±0.3 cm²）和14例年龄及性别相仿的正常受试者，获取升主动脉和左心室流出道在峰值流速、加速期半峰值流速（加速中期）和减速期半峰值流速（减速中期）时的血流速度多普勒测量值，以计算加速中期、峰值流速和减速中期的瞬时有效主动脉瓣口面积。在26例主动脉瓣狭窄患者中，加速中期的主动脉瓣面积为峰值流速时瓣膜面积的84±15%（p<0.0001），减速中期的瓣膜面积为峰值流速时测量值的113±17%（p<0.01）。相反，在正常受试者中，射血过程中主动脉瓣面积保持恒定，加速中期和减速中期分别为峰值流速时瓣膜面积的97±5%和99±6%（p>0.05）。此外，在主动脉瓣狭窄患者中，有效主动脉瓣面积从加速中期到减速中期的变化百分比差异很大，从 -17%到 +49%（平均变化 +26±14%）。有效瓣膜面积变化百分比与平均跨主动脉压力阶差（r = 0.05；p = 0.30）或峰值流速时的有效瓣膜面积（r = -0.11；p = 0.14）之间无相关性。我们的结果表明，主动脉瓣狭窄患者射血过程中有效主动脉瓣面积持续变化，且这种变化的幅度与狭窄严重程度的常用指标无关。相反，正常受试者射血过程中有效主动脉瓣面积保持恒定。
