Acute Stent-Induced Endothelial Denudation: Biomechanical Predictors of Vascular Injury

Abstract

Recent concern for local drug delivery and withdrawal of the first Food and Drug Administration-approved bioresorbable scaffold emphasizes the need to optimize the relationships between stent design and drug release with imposed arterial injury and observed pharmacodynamics. In this study, we examine the hypothesis that vascular injury is predictable from stent design and that the expanding force of stent deployment results in increased circumferential stress in the arterial tissue, which may explain acute injury poststent deployment. Using both numerical simulations and ex vivo experiments on three different stent designs (slotted tube, corrugated ring, and delta wing), arterial injury due to device deployment was examined. Furthermore, using numerical simulations, the consequence of changing stent strut radial thickness on arterial wall shear stress and arterial circumferential stress distributions was examined. Regions with predicted arterial circumferential stress exceeding a threshold of 49.5 kPa compared favorably with observed ex vivo endothelial denudation for the three considered stent designs. In addition, increasing strut thickness was predicted to result in more areas of denudation and larger areas exposed to low wall shear stress. We conclude that the acute arterial injury, observed immediately following stent expansion, is caused by high circumferential hoop stresses in the interstrut region, and denuded area profiles are dependent on unit cell geometric features. Such findings when coupled with where drugs move might explain the drug–device interactions.

Polymer–Metal Composite Healthcare Materials: From Nano to Device Scale

“…Compared to other implant biomaterials (e.g., dental implant, pacemaker, and joint replacement), the cardiovascular stent is placed in a bent vessel with continuous blood flow. The cardiovascular stent has to maintain structural integrity to prevent narrowing of the artery, and concurrently the stent should not exert too much circumferential stress on the artery that may lead to unnecessary trauma, subsequently leading to disease complications [261][262][263]. Therefore, the cardiovascular design requires the fine tuning of some extra macroscopic properties of the material, such as radial strength, elastic strength, and Poisson's ratio [264][265][266].…”

Intravascular imaging of angioplasty balloon under-expansion during pre-dilation predicts hyperelastic behavior of coronary artery lesions

“…While current imaging modalities are mostly geared toward morphology characterization, knowing material properties of the target lesion is a requirement to study plaque structural stress. Importantly, structural stress correlates strongly with poor outcomes of stent deployment including restenosis, stent thrombosis and plaque rupture ( Teng et al, 2014 ; Kolandaivelu and Rikhtegar, 2016 ; Costopoulos et al, 2017 ; Conway et al, 2021 ; Kadry et al, 2021 ). Local artery stiffness also predicts delivery balloon under-expansion and elastic recoil through stent-plaque strain energy exchange after balloon deflation ( Aziz et al, 2007 ).…”