BACKGROUND:The braided stent is a widely accepted endovascular treatment device consisting of woven metal wires. One of the unsolved issues for the braided stent is the stent flattening phenomena when deployed into highly curved arteries. Although a recent computational study highlighted that the mechanical state of the stent inside the catheter before the deployment plays an essential role in causing stent flattening, there is no experimental observation for the stent inside the curved catheter. OBJECTIVE:We investigated braided stent shapes in curved catheter tubes with various curvatures by micro-computed tomography (CT). METHODS:A braided stent was deployed into catheter tubes and set in rectangular cases with constant curvature. The three-dimensional shape of the stent was imaged by micro-CT, and its cross-sectional flatness was quantitatively assessed. RESULTS:Stent flattening occurred in cases of high curvatures of the outer side of the tube curvature, and the degree of flatness increased with increasing tube curvature. This demonstrates that stent flattening can be caused inside the highly curved catheter before deployment. CONCLUSIONS:This preliminary and first observational report provides new insight into the mechanism of stent flattening and emphasizes the importance of the geometrical and mechanical state of the stent inside the catheter.

中文翻译：

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编织支架在弯曲的导管内变平：微 CT 成像研究

背景：编织支架是一种广泛接受的血管内治疗装置，由金属丝编织而成。编织支架未解决的问题之一是当部署到高度弯曲的动脉时支架变平现象。虽然最近的一项计算研究强调，支架在展开前导管内的机械状态在导致支架变平方面起着至关重要的作用，但没有对弯曲导管内的支架进行实验观察。目的：我们通过显微计算机断层扫描 (CT) 研究了具有各种曲率的弯曲导管中的编织支架形状。方法：将编织支架置入导管内，置于曲率不变的矩形盒内。支架的三维形状通过微 CT 成像，并对其横截面平整度进行了定量评估。结果：在管子曲率外侧高曲率的情况下发生支架扁平化，且扁平度随管子弯曲度的增加而增加。这表明在展开之前，在高度弯曲的导管内会导致支架变平。结论：这份初步和第一份观察报告提供了对支架展平机制的新见解，并强调了导管内支架几何和机械状态的重要性。