Purpose

Stent malapposition is one of the most significant precursors of stent thrombosis and restenosis. Adverse haemodynamics may play a key role in establishing these diseases, although numerical studies have used idealised drug transport models to show that drug transport from malapposed drug-eluting stent struts can be significant. This paper aims to study whether drug transport from malapposed struts is truly significant. Another aim is to see whether a streamlined strut profile geometry – with a 61% smaller coating but a 32% greater coating-tissue contact area – can mitigate the adverse haemodynamics associated with stent malapposition while enhancing drug uptake.

Design/methodology/approach

Two- and three-dimensional computational fluid dynamics simulations were used in this study. Unlike past simulations of malapposed drug-eluting stent struts, a qualitatively validated drug-transport model which simulates the non-uniform depletion of drug within the drug coating was implemented.

Findings

It was shown that even a 10-µm gap between the strut and tissue dramatically reduces drug uptake after 24 h of simulated drug transport. Furthermore, the streamlined strut profile was shown to minimise the adverse haemodynamics of malapposed and well-apposed stent struts alike and enhance drug uptake.

Originality/value

Unlike prior numerical studies of malapposed stent struts, which did not model the depletion of drug in the drug coating, it was found that stent malapposition yields negligible drug uptake. The proposed semicircular-profiled strut was also shown to be advantageous from a haemodynamic and drug transport perspective.

中文翻译：

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支柱轮廓几何形状和贴壁不良对药物洗脱支架治疗动脉的血液动力学和药物转运行为的影响

目的

支架贴壁不良是支架内血栓形成和再狭窄最重要的前兆之一。不利的血液动力学可能在确定这些疾病中发挥关键作用，尽管数值研究使用理想化的药物传输模型表明来自贴壁不良的药物洗脱支架支柱的药物传输可能很重要。本文旨在研究从贴壁不良的支柱进行的药物转运是否真的具有重要意义。另一个目的是查看流线型支柱轮廓几何形状（涂层小 61% 但涂层与组织接触面积增加 32%）是否可以减轻与支架贴壁不良相关的不利血液动力学，同时提高药物摄取。

设计/方法/途径

本研究使用了二维和三维计算流体动力学模拟。与过去对贴壁不良的药物洗脱支架支柱的模拟不同，实施了一种经过定性验证的药物传输模型，该模型模拟药物涂层内药物的非均匀消耗。

发现

结果表明，在模拟药物运输 24 小时后，即使支柱和组织之间存在 10 µm 的间隙也会显着降低药物摄取。此外，流线型支柱轮廓被证明可以最大限度地减少贴壁不良和贴合良好的支架支柱的不利血液动力学，并增强药物摄取。

原创性/价值

与之前对贴壁不良的支架支柱的数值研究不同，后者没有模拟药物涂层中药物的消耗，发现支架贴壁不良产生的药物摄取可以忽略不计。从血液动力学和药物运输的角度来看，所提出的半圆形支柱也被证明是有利的。