Mascherbauer Julia, Fuchs Christina, Stoiber Martin, Schima Heinrich, Pernicka Elisabeth, Maurer Gerald, Baumgartner Helmut
Department of Cardiology, Medical University of Vienna, Vienna General Hospital, Vienna, Austria.
Eur Heart J. 2008 Aug;29(16):2049-57. doi: 10.1093/eurheartj/ehn209. Epub 2008 May 22.
Hypertension is a frequent finding in patients with aortic stenosis (AS). However, controversial data about the influence of systemic blood pressure on the quantification of AS have been published.
Various models of AS (plates and biological valves) were studied in an in vitro circuit. Valve areas were calculated with the Doppler continuity equation and the Gorlin formula. Systolic systemic pressures were increased from 80 to 200 mmHg while flow rates were maintained constant. In addition, a computational fluid dynamics (CFD) model was constructed to test the effect of systemic pressures on pressure gradient and valve area estimates. When systemic pressure was raised, pressure gradients as well as valve areas did not change (mean difference 3.4 +/- 1.8 mmHg, range 0.4-6.8 mmHg; mean difference 0.01 +/- 0.03 cm(2), range -0.02 to 0.05 cm(2)). By multivariable analysis, neither valve area nor pressure gradient were independently affected by systemic pressure. In addition, CFD analysis revealed no effect of systemic pressure on pressure gradient and valve area.
Our results suggest that blood pressure itself does not directly affect pressure gradients and valve area estimates in AS. Thus, when observed in vivo, these changes are most likely due to afterload-related variations of ejection fraction and, therefore, flow rate.
高血压在主动脉瓣狭窄（AS）患者中很常见。然而，关于体循环血压对AS定量影响的有争议的数据已经发表。
在体外循环中研究了各种AS模型（平板和生物瓣膜）。用多普勒连续方程和戈林公式计算瓣膜面积。在保持流速恒定的同时，将体循环收缩压从80 mmHg提高到200 mmHg。此外，构建了计算流体动力学（CFD）模型来测试体循环压力对压力梯度和瓣膜面积估计的影响。当体循环压力升高时，压力梯度和瓣膜面积均未改变（平均差异3.4±1.8 mmHg，范围0.4 - 6.8 mmHg；平均差异0.01±0.03 cm²，范围 - 0.02至0.05 cm²）。通过多变量分析，体循环压力对瓣膜面积和压力梯度均无独立影响。此外，CFD分析显示体循环压力对压力梯度和瓣膜面积没有影响。
我们的结果表明，血压本身不会直接影响AS中的压力梯度和瓣膜面积估计。因此，在体内观察到的这些变化很可能是由于射血分数与后负荷相关的变化，进而与流速有关。
