Hemodynamic diagnostics of epicardial coronary stenoses: in-vitro experimental and computational study.
Hemodynamic diagnostics of epicardial coronary stenoses: in-vitro experimental and computational study.
复制标题
心外膜冠状动脉炎症的血液动力学诊断：体外实验和计算研究。
DOI：
10.1186/1475-925x-7-24
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发表时间：
2008-08-27
影响因子：
3.9
通讯作者：
Khoury, Saeb F.
中科院分区：
文献类型：
--
作者：
Banerjee, Rupak K.;Ashtekar, Koustubh D.;Helmy, Tarek A.;Effat, Mohamed A.;Back, Lloyd H.;Khoury, Saeb F.
心外膜冠状动脉狭窄的严重程度可以通过有创性测量跨狭窄压降和流量来评估。在冠状动脉狭窄处插入压力或流量传感器尖端的导丝会导致高估真正的跨狭窄压降和冠脉流量的减少。这可能掩盖了冠状动脉狭窄的真实严重程度。为了揭示心外膜狭窄的真实严重程度，我们评估了一个诊断参数，该参数是根据基本的流体力学原理获得的。这项实验和数值研究的重点是诊断参数--压降系数的表征，以及对狭窄下游压力恢复的评估。在模拟心外膜冠状动脉网络的体外装置中，制作了三种冠状动脉狭窄模型，即中度狭窄、中度狭窄和重度狭窄。分别用体外压力和流量传感器和有创方法测量狭窄模型远端的跨狭窄压降和流量，并在狭窄处插入导丝。根据压降与流量的二次关系，计算了不同流量下压降的粘性分量和动量变化分量。最后计算出压降系数(CDPE)，即压降与远端动压的比值。压力恢复系数(η)计算为压力恢复系数与面积堵塞的比值。导丝置入前后的平均压降-流量特性表明，狭窄程度的增加会导致主力从粘性压力向动量的转变。然而，对于中度(~80%)狭窄，介于中度(~65%)和重度(~90%)之间的狭窄，两者的损失幅度相似。因此，置入导丝在评价冠状动脉狭窄的血流动力学严重程度中起着至关重要的作用。更重要的是，从中度狭窄到重度狭窄，平均CDPE增加(17±3.3~2 87±5 2，n=3，P<0.0 1)，平均η降低(0.5 4±0.0 4~0.37±0.0 5，P<0.0 1)。导丝的存在对CDPE的广泛范围没有太大影响。CDPE可用于临床评价冠状动脉狭窄的真实严重程度，因其在中度和重度狭窄时的测量值有显著差异。
The severity of epicardial coronary stenosis can be assessed by invasive measurements of trans-stenotic pressure drop and flow. A pressure or flow sensor-tipped guidewire inserted across the coronary stenosis causes an overestimation in true trans-stenotic pressure drop and reduction in coronary flow. This may mask the true severity of coronary stenosis. In order to unmask the true severity of epicardial stenosis, we evaluate a diagnostic parameter, which is obtained from fundamental fluid dynamics principles. This experimental and numerical study focuses on the characterization of the diagnostic parameter, pressure drop coefficient, and also evaluates the pressure recovery downstream of stenoses. Three models of coronary stenosis namely, moderate, intermediate and severe stenosis, were manufactured and tested in the in-vitro set-up simulating the epicardial coronary network. The trans-stenotic pressure drop and flow distal to stenosis models were measured by non-invasive method, using external pressure and flow sensors, and by invasive method, following guidewire insertion across the stenosis. The viscous and momentum-change components of the pressure drop for various flow rates were evaluated from quadratic relation between pressure drop and flow. Finally, the pressure drop coefficient (CDPe) was calculated as the ratio of pressure drop and distal dynamic pressure. The pressure recovery factor (η) was calculated as the ratio of pressure recovery coefficient and the area blockage. The mean pressure drop-flow characteristics before and during guidewire insertion indicated that increasing stenosis causes a shift in dominance from viscous pressure to momentum forces. However, for intermediate (~80%) area stenosis, which is between moderate (~65%) and severe (~90%) area stenoses, both losses were similar in magnitude. Therefore, guidewire insertion plays a critical role in evaluating the hemodynamic severity of coronary stenosis. More importantly, mean CDPe increased (17 ± 3.3 to 287 ± 52, n = 3, p < 0.01) and mean η decreased (0.54 ± 0.04 to 0.37 ± 0.05, p < 0.01) from moderate to severe stenosis during guidewire insertion. The wide range of CDPe is not affected that much by the presence of guidewire. CDPe can be used in clinical practice to evaluate the true severity of coronary stenosis due to its significant difference between values measured at moderate and severe stenoses.