Characterizing saccular aortic arch aneurysms from the geometry-flow dynamics relationship
Characterizing saccular aortic arch aneurysms from the geometry-flow dynamics relationship
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DOI：
10.1016/j.jtcvs.2016.11.032
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发表时间：
2017-06-01
影响因子：
6
通讯作者：
Washiyama, Naoki
中科院分区：
文献类型：
--
作者：
Natsume, Kayoko;Shiiya, Norihiko;Washiyama, Naoki
目的：低壁切应力（WSS）与动脉粥样硬化、动脉瘤生长或破裂加速有关。我们通过使用四维流动磁共振成像来评估主动脉弓动脉瘤的几何形状及其与WSS的关系，以更好地描述囊状动脉瘤。方法：我们使用计算机断层扫描的多平面重建来分析100例患者的几何形状。我们评估了WSS和涡流使用4维流动磁共振成像在其中16个，这是比较与8个年龄匹配的对照组和8个健康的年轻volunteers.Results：82例患者有一个囊状动脉瘤，18个梭形动脉瘤。梭形动脉瘤的外径/动脉瘤长度比和囊深/瘤颈宽度比恒定在0.76 +/- 0.18和0.23 +/- 0.09，而囊状动脉瘤，特别是涉及外曲率的动脉瘤的外径/动脉瘤长度比和囊深/瘤颈宽度比更高且更多变。动脉瘤内始终存在涡流，导致WSS较低。当囊深/瘤颈宽比小于0.8时，即使在囊状动脉瘤中，峰值WSS也与管腔直径呈负相关。当这一比率超过0.8，这是唯一的情况下，囊状动脉瘤，这种相关性不再存在，WSS总是low.Conclusions：梭形动脉瘤延长，因为他们扩张，WSS是较低的直径越大。囊状动脉瘤扩张不成比例地伸长，并且它们，尤其是那些占据内弯的囊状动脉瘤，具有较高且可变的囊深/瘤颈宽度比。当该比值超过0.8时，无论直径如何，WSS都很低，这可以解释它们的恶性临床行为。
Objective: Low wall shear stress (WSS) has been reported to be associated with accelerated atherosclerosis, aneurysm growth, or rupture. We evaluated the geometry of aortic arch aneurysms and their relationship with WSS by using the 4-dimensional flow magnetic resonance imaging to better characterize the saccular aneurysms.Methods: We analyzed the geometry in 100 patients using multiplanar reconstruction of computed tomography. We evaluated WSS and vortex flow using 4-dimensional flow magnetic resonance imaging in 16 of them, which were compared with 8 age-matched control subjects and eight healthy young volunteers.Results: Eighty-two patients had a saccular aneurysm, and 18 had a fusiform aneurysm. External diameter/aneurysm length ratio and sac depth/neck width ratio of the fusiform aneurysms were constant at 0.76 +/- 0.18 and 0.23 +/- 0.09, whereas those of saccular aneurysms, especially those involving the outer curvature, were higher and more variable. Vortex flow was always present in the aneurysms, resulting in low WSS. When the sac depth/neck width ratio was less than 0.8, peak WSS correlated inversely with luminal diameter even in the saccular aneurysms. When this ratio exceeded 0.8, which was the case only with the saccular aneurysms, such correlation no longer existed and WSS was invariably low.Conclusions: Fusiform aneurysms elongate as they dilate, and WSS is lower as the diameter is larger. Saccular aneurysms dilate without proportionate elongation, and they, especially those occupying the inner curvature, have higher and variable sac depth/neck width ratio. When this ratio exceeds 0.8, WSS is low regardless of diameter, which may explain their malignant clinical behavior.