scholarly journals A review of production technologies and materials for manufacturing of cardiovascular stents

2020 ◽  
Vol 15 (4) ◽  
pp. 390-402
Author(s):  
B. Polanec ◽  
J. Kramberger ◽  
S. Glodez
Keyword(s):  
Materials Science ◽  
Computational Modelling ◽  
Bare Metal Stents ◽  
Metal Stents ◽  
Element Analysis ◽  
Manufacturing Method ◽  
Treatment Techniques ◽  
Production Technologies ◽  
Manufacturing Technologies ◽  
Atherosclerosis Treatment

The purpose of this article is to give a general overview of the production technologies of stents with consideration of their design and materials. Since the beginning of the use of stents in medicine for atherosclerosis treatment, their development has changed rapidly. Various stents have also been developed with the development of materials science, treatment techniques and new manufacturing processes. In this way the development has shifted from the initial bare-metal stents (BMS), to drug-eluting stents (DES) and bio-resorbable stents (BRS), which are made of biodegradable polymers or metals. Various studies agree that it will be necessary to further review the experimentally obtained material properties with analytical and numerical studies. Here, the computational modelling (Finite element analysis - FEA and Computational fluid dynamics - CFD) was found as a valuable tool when evaluating stent mechanics and optimizing stent design. The development of the stent manufacturing technologies has also changed and been supplemented over the years. Nowadays, 3D printing could be an exciting manufacturing method to produce polymeric bio-materials, suitable for the latest generation of bio-degradable stents applications.

scholarly journals Computational Analysis of Mechanical Performance for Composite Polymer Biodegradable Stents

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6016
Author(s):  
Žiga Donik ◽  
Branko Nečemer ◽  
Matej Vesenjak ◽  
Srečko Glodež ◽  
Janez Kramberger
Keyword(s):  
Composite Structures ◽  
Mechanical Performance ◽  
Bare Metal Stents ◽  
Metal Stents ◽  
Elastic Recoil ◽  
Element Analysis ◽  
Biodegradable Stents ◽  
Vascular Scaffolds ◽  
Drug Eluting ◽  
Promising Solution

Bioresorbable stents (BRS) represent the latest generation of vascular scaffolds used for minimally invasive interventions. They aim to overcome the shortcomings of established bare-metal stents (BMS) and drug-eluting stents (DES). Recent advances in the field of bioprinting offer the possibility of combining biodegradable polymers to produce a composite BRS. Evaluation of the mechanical performance of the novel composite BRS is the focus of this study, based on the idea that they are a promising solution to improve the strength and flexibility performance of single material BRS. Finite element analysis of stent crimping and expansion was performed. Polylactic acid (PLA) and polycaprolactone (PCL) formed a composite stent divided into four layers, resulting in sixteen unique combinations. A comparison of the mechanical performance of the different composite configurations was performed. The resulting stresses, strains, elastic recoil, and foreshortening were evaluated and compared to existing experimental results. Similar behaviour was observed for material configurations that included at least one PLA layer. A pure PCL stent showed significant elastic recoil and less shortening compared to PLA and composite structures. The volumetric ratio of the materials was found to have a more significant effect on recoil and foreshortening than the arrangement of the material layers. Composite BRS offer the possibility of customising the mechanical behaviour of scaffolds. They also have the potential to support the fabrication of personalised or plaque-specific stents.

The Influence of Specimen Thickness in Quantitative Electron Energy Loss Spectroscopy

1980 ◽  
Vol 38 ◽  
pp. 112-113
Author(s):  
Nestor J. Zaluzec
Keyword(s):  
Quantitative Analysis ◽  
Adverse Effects ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Materials Science ◽  
Light Element ◽  
Specimen Thickness ◽  
Element Analysis ◽  
Electron Energy Loss

The application of electron energy loss spectroscopy (EELS) to light element analysis is rapidly becoming an important aspect of the microcharacterization of solids in materials science, however relatively stringent requirements exist on the specimen thickness under which one can obtain EELS data due to the adverse effects of multiple inelastic scattering.1,2 This study was initiated to determine the limitations on quantitative analysis of EELS data due to specimen thickness.

Drug-eluting stents for treatment of focal infrapopliteal lesions

VASA ◽  
2012 ◽  
Vol 41 (2) ◽  
pp. 90-95 ◽  
Author(s):  
Rastan ◽  
Noory ◽  
Zeller
Keyword(s):  
Limb Salvage ◽  
Bare Metal Stents ◽  
Target Lesion ◽  
Drug Eluting Stents ◽  
Metal Stents ◽  
Target Lesion Revascularisation ◽  
Randomized Studies ◽  
Drug Eluting ◽  
The Mean

We have investigated the role of drug-eluting stents on patency rates after treatment of focal infrapopliteal lesions in patients with intermittent claudication and critical limb ischemia. Reports indicate that drug-eluting stents reduce the risk of restenosis after percutaneous infrapopliteal artery revascularization. A Pub Med, EMBASE, Cochrane database review search of non-randomized studies investigating patency rates, target lesion revascularisation rates, limb salvage rates and mortality rates in an up to 3-year follow-up period after drug-eluting stent placement was conducted. In addition, preliminary results of randomized studies comparing drug-eluting stents with bare-metal stents and plain balloon angioplasty in treatment of focal infrapopliteal lesions were included in this review. A total of 1039 patients from 10 non-randomized and randomized studies were included. Most commonly used drug-eluting stents were sirolimus-eluting. The mean follow-up period was 12.6 (range 8 - 24). The mean 1-year primary patency rate was 86 ± 5 %. The mean target lesion revascularization rate and limb salvage rate was 9.9 ± 5 % and 96.6 %±4 %, respectively. Results from non-randomized and preliminary results from prospective, randomized trials show a significant advantage for drug-eluting stents in comparison to plain balloon angioplasty and bare-metal stents concerning target lesion patency and in parts target lesion revascularisation. No trial reveals an advantage for drug-eluting stents with regard to limb salvage and mortality.

Percutaneous Coronary Intervention in Patients with Diabetes and Multivessel or Left Main Disease – a Review

2012 ◽  
Vol 7 (1) ◽  
pp. 37
Author(s):  
Donald E Cutlip ◽  
Keyword(s):  
Percutaneous Coronary Intervention ◽  
Coronary Artery ◽  
Statistical Significance ◽  
Bare Metal Stents ◽  
Coronary Intervention ◽  
Metal Stents ◽  
Increased Risk ◽  
Percutaneous Coronary ◽  
Patients With Diabetes ◽  
The Impact

Coronary artery disease in patients with diabetes is frequently a diffuse process with multivessel involvement and is associated with increased risk for myocardial infarction and death. The role of percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG) in patients with diabetes and multivessel disease who require revascularisation has been debated and remains uncertain. The debate has been continued mainly because of the question to what degree an increased risk for in-stent restenosis among patients with diabetes contributes to other late adverse outcomes. This article reviews outcomes from early trials of balloon angioplasty versus CABG through later trials of bare-metal stents versus CABG and more recent data with drug-eluting stents as the comparator. Although not all studies have been powered to show statistical significance, the results have been generally consistent with a mortality benefit for CABG versus PCI, despite differential risks for restenosis with the various PCI approaches. The review also considers the impact of mammary artery grafting of the left anterior descending artery and individual case selection on these results, and proposes an algorithm for selection of patients in whom PCI remains a reasonable strategy.

Transbrachial and transfemoral approaches combined with visceral protection for the treatment of juxtarenal aortoiliac occlusive disease: Technical issues and clinical outcomes

Vascular ◽  
2021 ◽  
pp. 170853812110232
Author(s):  
Peixian Gao ◽  
Changliang Li ◽  
Xuejun Wu ◽  
Gang Li ◽  
Dianning Dong ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Bare Metal Stents ◽  
Covered Stent ◽  
Occlusive Disease ◽  
Metal Stents ◽  
Infrarenal Aorta ◽  
Bare Metal ◽  
Stent Grafts ◽  
Aortoiliac Occlusive Disease

Purpose To evaluate the safety and efficacy of transbrachial and transfemoral approaches combined with visceral protection for the endovascular treatment of juxtarenal aortoiliac occlusive disease (AIOD) over an average 19-month follow-up period. Methods In this retrospective analysis, all patients with juxtarenal AIOD at a single institution were reviewed from June 2015 to January 2020. Patient characteristics, angiographic results, and follow-up outcomes were retrospectively recorded. The indications for treatment were critical limb threatening ischemia in 12 patients and bilateral claudication in five patients. Percutaneous access via the left brachial artery was first obtained to recanalize the infrarenal occluded lesions. After that, femoral accesses were achieved. A 4-Fr catheter, a 4 mm balloon, or a 6-Fr 90-cm-long sheath was used to complete visceral artery protection. Results A total of 17 juxtarenal AIOD patients (14 males; mean age, 63.4 ± 8.1 years) underwent endovascular treatment. The technical success rate was 100%. Complete reconstruction was achieved in 15 (88.2%) patients. The infrarenal aorta was reconstructed with kissing covered stent grafts ( n = 7), kissing bare-metal stents ( n = 2), covered stent grafts ( n = 2), bare-metal stents ( n = 1), or the off-label use of iliac limb stent grafts ( n = 5). Renal embolization was found in 3 (17.6%) patients during intraoperative angiography. There was 1 (5.9%) case of distal runoff embolization after CDT and 1 (5.9%) case of left iliac artery rupture. One (5.9%) death occurred due to acute myocardial infarction 20 days after the operation. The average follow-up period was 19.3 ± 16.7 months (range, 1–54 months) in the remaining 16 cases. The renal artery patency rate was 100%. The estimated cumulative primary patency rates were 92.3% at 12 months and 59.3% at 36 months according to the Kaplan–Meier method. Conclusions Transbrachial and transfemoral approaches combined with visceral protection offer a safe and effective alternative to open revascularization for the endovascular treatment of juxtarenal AIOD.

scholarly journals The Use of Bioactive Polymers for Intervention and Tissue Engineering: The New Frontier for Cardiovascular Therapy

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 446 ◽  
Author(s):  
Francesco Nappi ◽  
Antonio Nenna ◽  
Domenico Larobina ◽  
Giorgia Martuscelli ◽  
Sanjeet Singh Avtaar Singh ◽  
...  
Keyword(s):  
Bare Metal Stents ◽  
Coronary Intervention ◽  
Myocardial Infarctions ◽  
Metal Stents ◽  
Long Term Effects ◽  
St Segment Elevation ◽  
Advantages And Disadvantages ◽  
Cardiovascular Therapy ◽  
St Segment ◽  
Drug Eluting

Coronary heart disease remains one of the leading causes of death in most countries. Healthcare improvements have seen a shift in the presentation of disease with a reducing number of ST-segment elevation myocardial infarctions (STEMIs), largely due to earlier reperfusion strategies such as percutaneous coronary intervention (PCI). Stents have revolutionized the care of these patients, but the long-term effects of these devices have been brought to the fore. The conceptual and technologic evolution of these devices from bare-metal stents led to the creation and wide application of drug-eluting stents; further research introduced the idea of polymer-based resorbable stents. We look at the evolution of stents and the multiple advantages and disadvantages offered by each of the different polymers used to make stents in order to identify what the stent of the future may consist of whilst highlighting properties that are beneficial to the patient alongside the role of the surgeon, the cardiologist, engineers, chemists, and biophysicists in creating the ideal stent.

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