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.

Relation of Drug-Eluting Stent Strut Distribution to Stent Thrombosis in Coronary Arteries

2009 ◽  
Vol 104 (3) ◽  
pp. 343-348 ◽  
Author(s):  
Maksymilian P. Opolski ◽  
Radoslaw Pracon ◽  
Gary S. Mintz ◽  
Teruo Okabe ◽  
Jerzy Pregowski ◽  
...  
Keyword(s):  
Stent Thrombosis ◽  
Coronary Arteries ◽  
Drug Eluting Stent ◽  
Stent Strut ◽  
Drug Eluting

scholarly journals Right coronary artery thrombosis within drug eluting stents more than 10 years after deployment

2017 ◽  
Vol 0 (Ahead of Print) ◽  
Author(s):  
Sam Lovibond ◽  
Michael Leung
Keyword(s):  
Coronary Artery ◽  
Stent Thrombosis ◽  
Drug Eluting Stents ◽  
Drug Eluting Stent ◽  
Late Stent Thrombosis ◽  
Very Late Stent Thrombosis ◽  
Artery Thrombosis ◽  
Coronary Artery Thrombosis ◽  
Drug Eluting ◽  
Initial Drug

We present two rare cases of very late stent thrombosis (VLST) occurring beyond ten years post initial drug eluting stent (DES) deployment

scholarly journals Safety and Efficacy of Second-Generation Drug-Eluting Stents in Real-World Practice: Insights from the Multicenter Grand-DES Registry

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
You-Jeong Ki ◽  
Kyung Woo Park ◽  
Jeehoon Kang ◽  
Chee-Hoon Kim ◽  
Jung-Kyu Han ◽  
...  
Keyword(s):  
Propensity Score ◽  
Stent Thrombosis ◽  
Real World ◽  
Coronary Intervention ◽  
Drug Eluting Stents ◽  
Drug Eluting Stent ◽  
Safety And Efficacy ◽  
Drug Eluting ◽  
Composite Outcomes

Objective. In this study, we sought to compare the efficacy and safety of the Xience Prime/Xience V/Promus EES and Biomatrix/Biomatrix Flex/Nobori BES with resolute integrity/resolute ZES using the grand drug-eluting stent (Grand-DES) registry. Background. Currently, new-generation drug-eluting stents (DESs) are used as the standard of care in patients undergoing percutaneous coronary intervention. No study has simultaneously compared everolimus-eluting stent (EES), biolimus-eluting stent (BES), and zotarolimus-eluting stent (ZES). Methods. Stent-related composite outcomes (target lesion failure) and patient-related composite outcomes were compared in crude and propensity score-matched analysis. Results. Of the 17,286 patients in the Grand-DES group, 5,137, 2,970, and 4,990 patients in the EES, BES, and ZES groups completed a three-year follow-up. In the propensity score-matched cohort, the stent-related outcome (EES vs. BES vs. ZES; 5.9% vs. 6.7% vs. 7.1%, P=0.226) and patient-related outcomes (12.7% vs. 13.5% vs. 14.3%, P=0.232) were similar among the three groups, at 3 years. The rate of definite or probable stent thrombosis (0.6% vs. 0.8% vs. 0.5%, P=0.549) was similar. In the multivariate analysis, chronic kidney disease was the strongest predictor of stent thrombosis (adjusted hazard ratio 3.178; 95% confidence interval 1.621–6.229; P<0.001). Conclusions. In this robust real-world registry with unrestricted use of EES, BES, and ZES, the three stent groups showed comparable safety and efficacy at the 3-year follow-up.

scholarly journals Very Late Stent Thrombosis 11 Years after Implantation of a Drug-Eluting Stent

2015 ◽  
Vol 42 (5) ◽  
pp. 487-490 ◽  
Author(s):  
Kevin Liou ◽  
Nigel Jepson
Keyword(s):  
Antiplatelet Therapy ◽  
Stent Thrombosis ◽  
Drug Eluting Stents ◽  
Drug Eluting Stent ◽  
Stent Insertion ◽  
Late Stent Thrombosis ◽  
Neointimal Formation ◽  
Very Late Stent Thrombosis ◽  
St Segment Elevation ◽  
Drug Eluting

Very late stent thrombosis is an infrequent yet potentially fatal complication associated with drug-eluting stents. We report the case of an 88-year-old man who sustained an ST-segment-elevation myocardial infarction 11 years after initial sirolimus-eluting stent implantation. Optical coherence tomograms of the lesion showed that the focal incomplete endothelialization of the stent struts was the likely cause; neointimal formation, neoatherosclerosis, and late stent malapposition might also have contributed. To our knowledge, this is the longest reported intervening period between stent insertion and the development of an acute coronary event secondary to very late stent thrombosis. The associated prognostic and therapeutic implications are considerable, because they illuminate the uncertainties surrounding the optimal duration of antiplatelet therapy in patients who have drug-eluting stents. Clinicians face challenges in treating these patients, particularly when competing medical demands necessitate the discontinuation of antiplatelet therapy. In addition to the patient's case, we discuss factors that can contribute to very late stent thrombosis.

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