Experimental Validation of the Influence of Stent Strut Compression on Artery Wall Drug Mass Transport

2009 ◽  
Author(s):  
Barry M. O’Connell ◽  
Tim M. McGloughlin ◽  
Michael T. Walsh
Keyword(s):  
Interventional Procedures ◽  
Experimental Validation ◽  
The Body ◽  
Drug Eluting Stents ◽  
Peripheral Arteries ◽  
Plaque Progression ◽  
Artery Wall ◽  
Stent Strut ◽  
Drug Eluting ◽  
Ischemic Attack

Atherosclerosis is a degenerative disease that affects coronary, carotid and other peripheral arteries in the body. Arterial occlusions ensuing from aggressive atherosclerotic plaque progression can often culminate in an ischemic attack, such as an apoplectic attack or a myocardial infarction [1–3]. Several interventional procedures are available to the clinician but in recent years drug eluting stents (DES) have become the preferred choice and by the beginning of 2006 more than 8 out of 10 coronary stents were DES [4] at a cost of between $4 and $5 billion annually [5].

Drug Eluting Stents: Modelling the Physics of Mass Transport in the Arterial Wall

2010 ◽  
Author(s):  
W. Denny ◽  
B. O’Connell ◽  
J. Milroy ◽  
M. Walsh
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Arteries ◽  
Arterial Wall ◽  
The Body ◽  
Drug Eluting Stents ◽  
Early 20Th Century ◽  
Peripheral Arteries ◽  
The Usa ◽  
Drug Eluting ◽  
Artery Disease

Coronary artery disease (CAD), which results in inadequate blood flow to the heart, is responsible for 1 in every 4.8 deaths in the USA (Lloyd-Jones et al., 2009). Currently, there are 16.5 million patients with stable angina and 500,000 new diagnoses annually (Gibbons et al., 2003). CAD has been linked with atherosclerosis since the early 20th century (McMahan et al., 2008) and refers to the localisation of the disease in the coronary arteries. Atherosclerosis is a degenerative disease that affects not only the coronary arteries, but also the carotid and other peripheral arteries in the body.

Stented Artery Biomechanics in the Presence of Stenoses and Tapering

2007 ◽  
Author(s):  
Lucas H. Timmins ◽  
Clark A. Meyer ◽  
Michael R. Moreno ◽  
James E. Moore
Keyword(s):  
Material Properties ◽  
Drug Eluting Stents ◽  
Bare Metal ◽  
Stent Design ◽  
Artery Wall ◽  
Technological Advances ◽  
Drug Eluting ◽  
Late Thrombosis ◽  
Induced Stresses ◽  
Human Implantation

The implantation of a balloon expandable stent induces chronic stent-induced stresses on the artery wall. These highly non-physiologic stresses can provoke inflammation and smooth muscle cell proliferation. Ultimately, this cascade of events leads to restenosis, or the development of a new blockage in the stented artery. Since the initial human implantation of balloon expandable stents, technological advances in stent design, material properties, and deliverability have expanded the application and success rate of the procedure. More recently, anti-restenotic strategies such as drug-eluting stents have aimed to counteract the restenosis process. While clinical trials have demonstrated the success of drug eluting stents in coronary arteries [1], risk of late thrombosis [2] and failure to prevent restenosis in peripheral arteries [3] has limited this technology. A further investigation into the artery wall stresses induced by stent implantation, and the pursuit of strategies to minimize them could reduce the restenosis rates for both bare metal and drug-eluting stents.

The Localized Hemodynamics of Drug-Eluting Stents Are Not Improved by the Presence of Magnetic Struts

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
P. R. S. Vijayaratnam ◽  
T. J. Barber ◽  
J. A. Reizes
Keyword(s):  
Blood Flow ◽  
Stent Thrombosis ◽  
Separated Flow ◽  
Drug Eluting Stents ◽  
Magnetic Flux Density ◽  
Drug Eluting Stent ◽  
Shear Stresses ◽  
Stent Strut ◽  
Drug Eluting ◽  
Wall Shear

The feasibility of implementing magnetic struts into drug-eluting stents (DESs) to mitigate the adverse hemodynamics which precipitate stent thrombosis is examined. These adverse hemodynamics include platelet-activating high wall shear stresses (WSS) and endothelial dysfunction-inducing low wall shear stresses. By magnetizing the stent struts, two forces are induced on the surrounding blood: (1) magnetization forces which reorient red blood cells to align with the magnetic field and (2) Lorentz forces which oppose the motion of the conducting fluid. The aim of this study was to investigate whether these forces can be used to locally alter blood flow in a manner that alleviates the thrombogenicity of stented vessels. Two-dimensional steady-state computational fluid dynamics (CFD) simulations were used to numerically model blood flow over a single magnetic drug-eluting stent strut with a square cross section. The effects of magnet orientation and magnetic flux density on the hemodynamics of the stented vessel were elucidated in vessels transporting oxygenated and deoxygenated blood. The simulations are compared in terms of the size of separated flow regions. The results indicate that unrealistically strong magnets would be required to achieve even modest hemodynamic improvements and that the magnetic strut concept is ill-suited to mitigate stent thrombosis.

Modeling Drug Eluting Stents for Coronary Artery Bifurcation Considering Non-Newtonian Effects

2010 ◽  
Author(s):  
Marjan Molavi Zarandi ◽  
Rosaire Mongrain ◽  
Olivier F. Bertrand
Keyword(s):  
Arterial Wall ◽  
Drug Eluting Stents ◽  
Drug Eluting Stent ◽  
Simulation Techniques ◽  
Drug Concentrations ◽  
Conventional Drug ◽  
Computational Fluid Dynamics Analysis ◽  
Stent Strut ◽  
Drug Eluting ◽  
Stenotic Arteries

Drug Eluting Stents (DES) are commonly used for the treatment of stenotic arteries. Restenosis can be treated by delivering anti-thrombotic and anti-proliferative drugs to the arterial wall. The main mechanism of the drug eluting stent is to allow diffusion of the drug from the coating on the stent, into the arterial wall over a prolonged period of time. Investigation of blood flow hemodynamics and shear stress are of great importance in understanding the transport of drugs through the circulatory systems and predicting the performance of drug eluting stents. While drug eluting stent effectively reduces restenosis rate, the conventional drug eluting stent should be optimized to be used in the bifurcation stenting. Various flow patterns due to specific designs of drug eluting stent influence drug delivery. Numerical simulation techniques are appropriate approaches to study such phenomena which can be used to optimize the design of drug eluting stents for bifurcations. In this paper, the complexity of drug eluting stent function in the bifurcation is presented by employing computational fluid dynamics analysis for various stent strut designs. Drug transportation through the lumen and determination of local drug concentrations in arterial wall is carried out for both Newtonian and non-Newtonian flow conditions. It is, to the author’s best knowledge, the first investigation of drug dispersion in arterial bifurcation considering the effects of both the blood rheological properties and stent strut design.

scholarly journals Factors that affect mass transport from drug eluting stents into the artery wall

2010 ◽  
Vol 9 (1) ◽  
pp. 15 ◽  
Author(s):  
Barry M O'Connell ◽  
Tim M McGloughlin ◽  
Michael T Walsh
Keyword(s):  
Mass Transport ◽  
Drug Eluting Stents ◽  
Artery Wall ◽  
Drug Eluting

scholarly journals Coronary Stent Strut Fractures: Classification, Prevalence and Clinical Associations

2021 ◽  
Vol 10 (8) ◽  
pp. 1765
Author(s):  
Katharina Schochlow ◽  
Melissa Weissner ◽  
Florian Blachutzik ◽  
Niklas F. Boeder ◽  
Monique Tröbs ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Multivariable Analysis ◽  
Drug Eluting Stents ◽  
Clinical Implications ◽  
Device Failure ◽  
Stent Strut ◽  
Drug Eluting ◽  
Bifurcation Lesions ◽  
Clinical Associations ◽  
Device Complications

Introduction. The frequency, characteristics and clinical implications of Strut fractures (SFs) remain incompletely understood. Methods and results. A total of 185 (160 patients) newer-generation drug-eluting stents (DES) were imaged. SFs were found in 21 DES (11.4%) and were classified in four patterns: one single stacked strut (41%); two or more stacked struts (23%); deformation without gap (27%); transection (9%). In multivariable analysis, calcific and bifurcation lesions were associated with SF in DES (OR: 3.5 [1.1–11] and 4.0 [2.2–7.2], p < 0.05). Device eccentricity and asymmetry as well as optical coherence tomography (OCT) features of impaired strut healing were also associated with SF. The prevalence of fractures was similar in a set of 289 bioresorbable scaffolds (BRS). In a separate series of 20 device thromboses and 36 device restenoses, the prevalence of SF was higher (61.2% of DES and 66.7% of BRS, p < 0.001 for both), with a higher frequency of complex SF patterns (p < 0.0001). In logistic regression analysis, fractures were a correlate of device complications (p < 0.0001, OR = 24.9 [5.6–111] for DES and OR = 6.0 [1.8–20] for BRS). Discussion. The prevalence of OCT-diagnosed SF was unexpectedly high in the setting of elective controls and it increased by about three-fold in the setting of device failure. Fractures were associated with increased lesion complexity and device asymmetry/eccentricity and were more frequent in the setting of device failure such as restenosis and thrombosis.

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