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Intravascular Ultrasound for Molecular Imaging
Published in Robert J. Gropler, David K. Glover, Albert J. Sinusas, Heinrich Taegtmeyer, Cardiovascular Molecular Imaging, 2007
To enhance interventional outcomes, stents were developed to maintain lumen diameter after the balloon intervention. Stents are meshed scaffold tubes implanted in a vessel and delivered over an angioplasty balloon. Since gaining FDA approval in 1994, they have become the primary interventional procedure accounting for a majority of angioplasty procedures in catheterization labs (11). Stents effectively prop open the occluded vessel by pushing on the plaque and arterial wall to expand lumen diameter. Clinical complications related to stent deployment are underdeployment and overdeployment. Underdeployment can lead to stent collapse if it is not in complete contact with the vessel lumen. Furthermore, blood can collect in the gap between the arterial tissues, leading to thrombosis.
Mechanical Effects of Cardiovascular Drugs and Devices
Published in Michel R. Labrosse, Cardiovascular Mechanics, 2018
An intravascular stent is a synthetic tubular structure intended for permanent implant in native or graft vasculature. The stent is designed to provide radial mechanical support after deployment, which is meant to enhance vessel patency over the life of the device. The stent is delivered with a catheter inserted into an arterial vessel, in the same type of procedure used for vascular dilatation. Once the stent reaches the target location under image guidance, it is expanded by a balloon or self-expanding mechanism. Stents were developed to address the growing problem with restenosis following balloon angioplasty treatment. As mentioned previously, restenosis rates of 25%–50% within 6 months are common, which diminishes the cost-effectiveness of PCI.
The Problem of Technology
Published in Cameron La Follette , Chris Maser, Sustainability and the Rights of Nature, 2017
Cameron La Follette , Chris Maser
Then there is the creation and implantation of such technological constructs as medical stents, which do not simulate a body part but are nonetheless essential for body function in the case of partial breakdown. A stent is a thin, flexible tube (catheter), usually of metal mesh, that is used to treat narrow or weak arteries, which are blood vessels that carry blood away from the heart to other parts of the body. The stent is inserted through the skin in the upper thigh or arm into the artery to improve the flow of blood and help prevent the artery from bursting.
Comparison of blood flow analysis in stenosed and stented carotid artery bifurcation models
Published in Cogent Engineering, 2023
M. Saqib Hameed, Awais Ahmad Shah, Muhammad Irfan Khan, Awais Ali, Imtiaz Hussain, Muhammad Dawood Bukhari
The normal blood flow in the carotid artery means that the artery is free of any significant blockage or narrowing. A stroke occurs when the supply of blood to brain is interrupted or reduced. This prevents the supply of oxygen and nutrients to the brain and as a result brain cells start dying within minutes of a stroke. The estimated risk of stroke in a lifetime for an individual 25 years or above was 22.8% in 1990; the risk has increased to 24.9% in 2016 (Gorelick, 2019). Atherosclerosis is a cause of carotid stenosis, which results in the narrowing of the carotid artery because of plaque buildup. A patient with a completely blocked carotid artery is at an increased risk of stroke. A computed tomography angiography (CTA; Kigka et al., 2019) or Doppler ultrasound of the neck (Brook, 2020), magnetic resonance angiography (Cavallo et al., 2019), or a cerebral angiogram (Allison et al., 2021) are used to diagnose carotid stenosis. The condition is often treated with a minimally invasive procedure called carotid artery stenting (Ahn et al., 2013; White et al., 2022), which compresses the plaque and increases the lumen of an artery. A stent is a self-expanding mesh-like structure of tubular form, which is placed inside the artery to remove blockage of blood flow. Patients with moderate to high-grade carotid stenosis (more than 70%) are typically suggested a stenting procedure. The post-procedure angiograms demonstrate a high precision in which a stent restores the vessel to its normal dimension (Wholey & Finol, 2007).
Computational analysis of designing an improved coronary stents of biodegradable Poly-lactic Acid (PLA)
Published in Australian Journal of Mechanical Engineering, 2022
Salim Lounansa, Hacene Ameddah, Hammoudi Mazouz, Ebrahim Ahmed Ali Alkebsi
Known as ‘the blood vessels’, coronary arteries are essential to the alimentation of oxygen-rich blood to keep it healthy of the heart. They are revived and treated because it is one of the most important organs responsible for maintaining the pumping of blood in the human body (Bora et al. 2019; Torki, Hassanajili, and Jalisi 2020). In coronary arteries, atherosclerotic takes large problems due to the accumulation of lipids, which leads to ischaemia in the heart (Chen et al. 2021; Lee et al. 2020). Stents are effectively used in the treatment of the atherosclerotic because they help to retrieve blood flow in diseased blood vessels to its distinctive mechanical characteristics (radial strength, expanding deformability, bending flexibility, radial recoil and long fatigue life) (Wang et al. 2018; Wei et al. 2019; Yadav et al. 2022; Belaghit et al. 2018). The motivation for this study is that most problems of stents are caused by the complication after transplantation, which prevents the restoration of the normal biological functions of blood vessels (Zhao and Feng 2020; Wang et al. 2018). These problems are caused by the effect of material properties and geometry on the performance of stents after transplantation. The risks appear as a result of the biological incompatibility between arteries and permanent stents, especially in the case of in-stent stenosis, late thrombosis, and hypersensitivity reactions (Borhani et al. 2018; Peng et al. 2019).
The role of nanomaterials and nanostructured surfaces for improvement of biomaterial peculiarities in vascular surgery: a review
Published in Particulate Science and Technology, 2021
Marius Fodor, Lucian Fodor, Olimpiu Bota
The existence of the stent in the vessel is only necessary for a limited amount of time. Beyond this point, the stent may cause thrombogenicity and inflammation and may cause mechanical mismatch (O'Brien et al. 2016). The trend in the development of vascular stents in order to prevent late stent thrombosis is to eliminate the cause completely by using biodegradable stents with no polymer carrier. The first resorbable stents were fabricated from poly-L-lactic acid, which may take 18–24 months to resorb (Serruys et al. 2011; Diletti et al. 2012). Tyrosine polycarbonate incorporating iodine molecules is another substance used for biodegradable stents (Onuma and Serruys 2011). Desaminotyrosine polycarbonate polymer is a compound that is supposed to reduce the thickness of the stent struts while maintaining the radial strength (Koltowski et al. 2020). A meta-analysis comparing bioabsorbable polymer drug-eluting stents with durable polymer drug-eluting stents and bare-metal stents has shown improved results for the bioabsorbable stents compared to bare metal stents and first-generation drug-eluting stents (Palmerini et al. 2014).