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The cardiovascular system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Mary N Sheppard, C. Simon Herrington
Unfortunately, the early use of balloon angioplasty led to thrombosis and rapid restenosis of the coronary artery due to intimal healing with smooth muscle cell hyperplasia. The application of a metallic stent to keep the coronary artery open improved the long-term patency of the vessels. The complication of stent thrombosis was overcome with the introduction of effective anti-platelet therapy. The introduction of drug-eluting stents, which slow smooth muscle growth, helped to reduce restenosis. Primary angioplasty with stent insertion is now the treatment of choice for patients with acute myocardial infarction. Late stent thrombosis can occur and histopathological data implicate a contributory allergic or hypersensitivity component.
Stents, covered stents, stent–grafts
Published in Peter A. Schneider, Endovascular Skills: Guidewire and Catheter Skills for Endovascular Surgery, 2019
Each stent application has its own cost and complication risks. The sheath must usually be upsized, a foreign body is implanted, and stents have their own unique complications. Stents in some locations, such as the lower extremity or the renal artery, seem to be particularly susceptible to recurrent stenosis. The cost of each stent increases the overall cost of an endovascular intervention. The placing of stents may be motivated by the wish to extend the short- or long-term success of balloon angioplasty, to avoid surgery, or to avoid repeat balloon angioplasty, but this should be considered in each case. Stents have improved to the point where they can be easily and smoothly incorporated into a procedure, even if a stent was not necessarily intended from the start of the case. Drug-eluting stents have the potential, once fully developed, to decrease or prevent intimal hyperplasia.
Angina
Published in Clive Handler, Gerry Coghlan, Nick Brown, Management of Cardiac Problems in Primary Care, 2018
Clive Handler, Gerry Coghlan, Nick Brown
This is due to fibromuscular hypertrophy following inevitable trauma to the vessel wall at the site of balloon dilatation. Drug-eluting stents were developed in order to try to reduce this problem. The risks of restenosis, and therefore the need for further revascularisation, are significantly lower with a drug-eluting stent compared with a bare metal stent. However, there is no evidence that restenosis is of prognostic importance. Unexpected atheromatous plaque rupture, rather than restenosis, is the cause of infarction and death.
The challenges of drug delivery to the esophagus and how to overcome them
Published in Expert Opinion on Drug Delivery, 2022
Julius Krause, Friederike Brokmann, Christoph Rosenbaum, Werner Weitschies
The new, innovative delivery systems for esophageal application represent interesting approaches, however, some of them also raise questions about their applicability in humans. In the case of magnetic drug targeting, it seems at least questionable whether this therapy option can also be transferred to humans. Among others, open questions are the positioning of the patient, the need for a sufficiently strong magnet to create an effective gradient field, and the question of suitable magnetic excipients. The esophageal flower-like system is doubtlessly highly innovative. However, a crucial question will be how to ensure that the system unfolds at the desired location in the esophagus. If this system unfolds too early or too late, it might be dangerous for the patient. In contrast to these systems, drug-free stents have already found their way into practice. It is probably to be expected that, as in cardiology, drug-eluting stents will also enter clinical practice to prevent or at least reduce complications such as tissue overgrowth.
An overview of PLGA in-situ forming implants based on solvent exchange technique: effect of formulation components and characterization
Published in Pharmaceutical Development and Technology, 2021
Tarek Metwally Ibrahim, Nagia Ahmed El-Megrab, Hanan Mohammed El-Nahas
On the other hand, polymeric implant systems are specific-shaped masses that are composed of a biocompatible biodegradable or non-biodegradable polymer. They are generally implanted by using an injector device and must be finally removed in case of utilizing a non-biodegradable polymer such as Nexplanon® and Iluvien® (Stewart et al. 2018). Ozurdex® is rod-shaped biodegradable PLGA-based implants that depend on Allergan’s Novadur® technology and are utilized for the treatment of diabetic macular edema via intravitreal dexamethasone administration (Jervis 2017). Drug-eluting stents are specific double-action systems generally consisted of a stent as the device component and a drug-containing coating as the drug component. As an example, Coroflex® ISAR NEO can provide a prolonged release of sirolimus, embedded in the drug-eluting coating, used for prevention of myointimal proliferation and reduction of restenosis with the assistance of the mechanical support of the stent that can maintain the open vasculature and arterial patency (Al-Jawadi et al. 2018).
Therapeutic advances in cardiac targeted drug delivery: from theory to practice
Published in Journal of Drug Targeting, 2021
Cuican Li, Muhammad Naveed, Kashif Dar, Ziwei Liu, Mirza Muhammad Faran Ashraf Baig, Rundong Lv, Muhammad Saeed, Chen Dingding, Yu Feng, Zhou Xiaohui
Percutaneous coronary intervention (PCI) is a traditional mainstay in treating coronary artery disease (CAD). No reflow and vasospasm after PCI will result in more complications and even death. After PCI, IC injection via a catheter or perforated balloon in the treatment of no-reflow and vasospasm symptoms proved safe and effective in several clinical studies [54–56]. Drug-eluting stents can also be used to reduce restenosis after surgery (Table 2). Sun and associates also proposed that IC injection tirofiban during PCI could prevent microcirculatory dysfunction [57]. Clinical trials by Giuseppe and colleagues [58], Mohamed, and associates [59] had all demonstrated better myocardial perfusion and restoration of cardiac function and safety compared to IV infusion, but their audiences are more favourable to critically ill patients.