Department of Mechanical Engineering, Stanford University, USA.
The Hospital for Sick Children, University of Toronto, Canada.
Int J Cardiol. 2019 Apr 15;281:15-21. doi: 10.1016/j.ijcard.2019.01.092. Epub 2019 Jan 28.
Thrombosis is a major adverse outcome associated with coronary artery aneurysms (CAAs) resulting from Kawasaki disease (KD). Clinical guidelines recommend initiation of anticoagulation therapy with maximum CAA diameter (D) ≥8 mm or Z-score ≥ 10. Here, we investigate the role of aneurysm hemodynamics as a superior method for thrombotic risk stratification in KD patients.
We retrospectively studied ten KD patients with CAAs, including five patients who developed thrombosis. We constructed patient-specific anatomic models from cardiac magnetic resonance images and performed computational hemodynamic simulations using SimVascular. Our simulations incorporated pulsatile flow, deformable arterial walls and boundary conditions automatically tuned to match patient-specific arterial pressure and cardiac output. From simulation results, we derived local hemodynamic variables including time-averaged wall shear stress (TAWSS), low wall shear stress exposure, and oscillatory shear index (OSI). Local TAWSS was significantly lower in CAAs that developed thrombosis (1.2 ± 0.94 vs. 7.28 ± 9.77 dynes/cm, p = 0.006) and the fraction of CAA surface area exposed to low wall shear stress was larger (0.69 ± 0.17 vs. 0.25 ± 0.26%, p = 0.005). Similarly, longer residence times were obtained in branches where thrombosis was confirmed (9.07 ± 6.26 vs. 2.05 ± 2.91 cycles, p = 0.004). No significant differences were found for OSI or anatomical measurements such us D and Z-score. Assessment of thrombotic risk according to hemodynamic variables had higher sensitivity and specificity compared to standard clinical metrics (D, Z-score).
Hemodynamic variables can be obtained non-invasively via simulation and may provide improved thrombotic risk stratification compared to current diameter-based metrics, facilitating long-term clinical management of KD patients with persistent CAAs.
血栓形成是川崎病（KD）导致的冠状动脉瘤（CAA）的主要不良后果。临床指南建议对最大 CAA 直径（D）≥8mm 或 Z 评分≥10 的患者开始抗凝治疗。在这里，我们研究了动脉瘤血流动力学作为 KD 患者血栓形成风险分层的一种更好方法的作用。
我们回顾性研究了 10 例 CAA 合并 KD 患者，其中 5 例发生血栓形成。我们从心脏磁共振图像构建了患者特异性解剖模型，并使用 SimVascular 进行了计算血流动力学模拟。我们的模拟纳入了脉动流、可变形动脉壁和自动调整以匹配患者特定动脉压和心输出量的边界条件。从模拟结果中，我们得出了局部血流动力学变量，包括平均壁切应力（TAWSS）、低壁切应力暴露和振荡剪切指数（OSI）。发生血栓形成的 CAA 中的局部 TAWSS 明显较低（1.2±0.94 与 7.28±9.77 dynes/cm，p=0.006），并且暴露于低壁切应力的 CAA 表面积分数更大（0.69±0.17 与 0.25±0.26%，p=0.005）。同样，在血栓形成得到证实的分支中，停留时间更长（9.07±6.26 与 2.05±2.91 个循环，p=0.004）。OSI 或 D 和 Z 评分等解剖学测量值没有差异。与标准临床指标（D、Z 评分）相比，根据血流动力学变量评估血栓形成风险具有更高的敏感性和特异性。
血流动力学变量可以通过模拟无创获得，并且与基于直径的现有指标相比，可能提供更好的血栓形成风险分层，有助于 KD 患者持续 CAA 的长期临床管理。
