Endovascular Implants
Wilmer W Nichols, Michael F O'Rourke, Elazer R Edelman, Charalambos Vlachopoulos in McDonald's Blood Flow in Arteries, 2022
Pharmacological solutions including systemic dual antiplatelet therapy (DAPT) reduced stent thrombosis but with no discernible effects on restenosis (Mehta and Yusuf, 2000; Woods and Marks, 2004) and, with each increment in systemic dosing, side effects emerged. The idea of local drug delivery tied to endovascular implants emerged to provide ample dosing at the site of injury and widen the therapeutic window (Edelman et al., 1990, 1993). Thus drug-eluting stents (DES) were developed where an antiproliferative drug carrier was coated on the metallic backbone of the device to minimize neointimal growth, prevent restenosis and reduce reintervention (Drachman et al., 2000). The new challenge, though, was to achieve safe and effective DES with appropriate device, suitable release kinetics and sufficient drug embedment (Edelman and Rogers, 1998; Welt et al., 2000). In search of drugs with avid tissue binding and high tissue retention, paclitaxel and sirolimus were first introduced to the market with outstanding vascular retention and prolonged biological effects (Woods and Marks, 2004; Creel et al., 2000; Hwang et al., 2003; Hwang and Edelman, 2002; Lovich et al., 2001). In 2003, the Cypher sirolimus-eluting stent and a year later the Taxus paclitaxeleluting device further transformed interventional medicine.
Stents, covered stents, stent–grafts
Peter A. Schneider in 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.
Surgical treatments and approaches
ILEANA PIÑA, SIDNEY GOLDSTEIN, MARK E DUNLAP in The Year in Heart Failure, 2005
CABG should be considered in all patients with left ventricular dysfunction and targets for revascularization. There is currently sufficient data to mandate viability studies in all patients and those without viability should be treated medically. CABG should be performed on these patients in centres of excellence, with high surgical volumes and, ideally, with left ventricular assist device backup available. The recent blossoming of the drug-eluting stent field further complicates management decisions. Percutaneous revascularization, with minimal restenosis, has become a reality 1291. How this will potentially impact on revascularization of patients with ischaemic cardiomyopathy remains to be elucidated. Extensive experience in the use of left ventricular reconstruction has confirmed that it carries a low peri-operative mortality and excellent intermediate and longterm survival 125,30-351. Left ventricular reconstruction should be considered in centres proficient in this technique, when there are discrete akinetic or dyskinetic regions. Surgery should generally be combined with a multifaceted approach and peri-operative evaluation should include viability studies.
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).
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.
Percutaneous coronary intervention in patients with essential thrombocythemia: case reports and literature review
Published in Platelets, 2020
Yaguo Zheng, Tian Xu, Liang Chen, Song Lin, Shaoliang Chen
Optimal treatment modalities for these patients are not clear. Primary angioplasty, thrombolytic therapy, and coronary artery bypass graft surgery are of choice [12]. Although the short-term effectiveness of drug-eluting stent has been demonstrated in several studies, the long-term effect is not clear. We could find 21 case reports in patients with ET who had been treated with PCI from 1984 to 2019 in the literature (Table II) [2,3,5,8,9,13–28]. The major concern is stent thrombus and restenosis. It is commonly believed that PCI and stent implantation may be associated with a higher rate of complications and adverse events in this subset of patients. In this study, although most patients received dual antiplatelet and cytoreduction therapy, 3 of 8 patients developed stent thrombus and restenosis in the follow-up. The proportion is relatively high. It was consistent with previous reports. Shoji et al. [28] reported a patient with acute myocardial infarction complicated with ET which developed in-stent massive thrombi after stent deployment. Campo et al. [20] summarized 15 patients with ET undergoing PCI, and found that four events including two re-infarctions and two target vessel revascularization were reported during 22 ± 13 months follow-up. We think it can be explained by the high platelet count and reactivity in these patients, despite treatment with cytoreduction and dual antiplatelet.
Related Knowledge Centers
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