Multi-Modality Medical Imaging M3i Group, TechMed Centre, University of Twente, Drienerlolaan 5, 7522 NB, Enschede, The Netherlands.
Department of Surgery, Rijnstate, Arnhem, The Netherlands.
Cardiovasc Intervent Radiol. 2024 May;47(5):533-542. doi: 10.1007/s00270-024-03708-x. Epub 2024 Apr 2.
In arterial disease, the presence of two or more serial stenotic lesions is common. For mild lesions, it is difficult to predict whether their combined effect is hemodynamically significant. This study assessed the hemodynamic significance of idealized serial stenotic lesions by simulating their hemodynamic interaction in a computational flow model.
Flow was simulated with SimVascular software in 34 serial lesions, using moderate (15 mL/s) and high (30 mL/s) flow rates. Combinations of one concentric and two eccentric lesions, all 50% area reduction, were designed with variations in interstenotic distance and in relative direction of eccentricity. Fluid and fluid-structure simulations were performed to quantify the combined pressure gradient.
At a moderate flow rate, the combined pressure gradient of two lesions ranged from 3.8 to 7.7 mmHg, which increased to a range of 12.5-24.3 mmHg for a high flow rate. Eccentricity caused an up to two-fold increase in pressure gradient relative to concentric lesions. At a high flow rate, the combined pressure gradient for serial eccentric lesions often exceeded the sum of the individual lesions. The relative direction of eccentricity altered the pressure gradient by 15-25%. The impact of flow pulsatility and wall deformability was minor.
This flow simulation study revealed that lesion eccentricity is an adverse factor in the hemodynamic significance of isolated stenotic lesions and in serial stenotic lesions. Two 50% lesions that are individually non-significant can combine more often than thought to hemodynamic significance in hyperemic conditions.
在动脉疾病中，存在两个或多个连续狭窄病变是很常见的。对于轻度病变，很难预测它们的联合作用是否具有血流动力学意义。本研究通过在计算血流模型中模拟其血流动力学相互作用，评估理想化连续狭窄病变的血流动力学意义。
使用 SimVascular 软件模拟 34 个连续病变的血流，使用中等（15 mL/s）和高（30 mL/s）流量。设计了具有不同狭窄间距离和相对偏心方向的同心和两个偏心病变的组合，所有病变均有 50%的面积减少。进行了流体和流固耦合模拟，以量化组合压力梯度。
在中等流量下，两个病变的组合压力梯度范围为 3.8 至 7.7 mmHg，在高流量下增加至 12.5 至 24.3 mmHg 的范围。偏心导致压力梯度相对于同心病变增加了一倍。在高流量下，连续偏心病变的组合压力梯度通常超过单个病变的总和。偏心的相对方向使压力梯度改变了 15-25%。血流脉动和壁变形的影响较小。
这项血流模拟研究表明，病变偏心是孤立性狭窄病变和连续狭窄病变血流动力学意义的不利因素。两个单独非显著的 50%病变在充血条件下比想象的更容易结合产生血流动力学意义。
