Role of polymers in improving the results of stenting in coronary arteries

Peng, Tao; Gibula, Paul; Yao, Kangde; Goosen, Mattheus F. A.

doi:10.1016/0142-9612(96)86738-x

Cited by 104 publications

(51 citation statements)

References 45 publications

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“…The biocompatibility of PHBV has been studied (9) and the material has also been investigated for the improvement of blood vessel restoration (10).…”

Section: Introductionmentioning

confidence: 99%

Use of blends of bioabsorbable poly(L-lactic acid)/poly(hydroxybutyrate- co-hydroxyvalerate) as surfaces for Vero cell culture

Santos

Ferreira

Duek

et al. 2005

Braz J Med Biol Res

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Vero cells, a cell line established from the kidney of the African green monkey (Cercopithecus aethiops), were cultured in F-10 Ham medium supplemented with 10% fetal calf serum at 37°C on membranes of poly(L-lactic acid) (PLLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and their blends in different proportions (100/0, 60/40, 50/50, 40/60, and 0/100). The present study evaluated morphology of cells grown on different polymeric substrates after 24 h of culture by scanning electron microscopy. Cell adhesion was also analyzed after 2 h of inoculation. For cell growth evaluation, the cells were maintained in culture for 48, 120, 240, and 360 h. For cytochemical study, the cells were cultured for 120 or 240 h, fixed, processed for histological analysis, and stained with Toluidine blue, pH 4.0, and Xylidine ponceau, pH 2.5. Our results showed that cell adhesion was better when 60/40 and 50/50 blends were used although cells were able to grow and proliferate on all blends tested. When using PLLA/PHBV (50/50) slightly flattened cells were observed on porous and smooth areas. PLLA/PHBV (40/60) blends presented flattened cells on smooth areas. PLLA/PHBV (0/100), which presented no pores, also supported spreading cells interconnected by thin filaments. Histological sections showed that cells grew as a confluent monolayer on different substrates. Cytochemical analysis showed basophilic cells, indicating a large amount of RNA and proteins. Hence, we detected changes in cell morphology induced by alterations in blend proportions. This suggests that the cells changed their differentiation pattern when on various PLLA/PHBV blend surfaces. Correspondence

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“…The biocompatibility of PHBV has been studied (9) and the material has also been investigated for the improvement of blood vessel restoration (10).…”

Section: Introductionmentioning

confidence: 99%

Use of blends of bioabsorbable poly(L-lactic acid)/poly(hydroxybutyrate- co-hydroxyvalerate) as surfaces for Vero cell culture

Santos

Ferreira

Duek

et al. 2005

Braz J Med Biol Res

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“…Unlike BMSs, polymer stents can achieve increased hemocompatibility with the proper selection of polymer components, polymerization and processing techniques [9]. With regard to DESs, these stents have been shown to cause a delay in re-endothelialization, therefore promoting a thrombotic environment compared to BMSs, as re-endothelialization is an important component in vessel healing.…”

Section: Current Stents and Associated Issuesmentioning

confidence: 99%

“…Thrombotic events often occur due to net electrical charge differences between blood components and the stent surface, as well as surface potential incompatibility between the metal and the contacting blood [9,10]. Restenosis, or re-narrowing of the vessel, usually results from excessive neointimal proliferation following balloon angioplasty or stent implantation due to vessel injury from the expansion [11][12][13].…”

Section: Current Stents and Associated Issuesmentioning

confidence: 99%

A Survey of Surface Modification Techniques for Next-Generation Shape Memory Polymer Stent Devices

Govindarajan

Shandas

2014

Polymers

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Abstract:The search for a single material with ideal surface properties and necessary mechanical properties is on-going, especially with regard to cardiovascular stent materials. Since the majority of stent problems arise from surface issues rather than bulk material deficiencies, surface optimization of a material that already contains the necessary bulk properties is an active area of research. Polymers can be surface-modified using a variety of methods to increase hemocompatibilty by reducing either late-stage restenosis or acute thrombogenicity, or both. These modification methods can be extended to shape memory polymers (SMPs), in an effort to make these materials more surface compatible, based on the application. This review focuses on the role of surface modification of materials, mainly polymers, to improve the hemocompatibility of stent materials; additional discussion of other materials commonly used in stents is also provided. Although shape memory polymers are not yet extensively used for stents, they offer numerous benefits that may make them good candidates for next-generation stents. Surface modification techniques discussed here include roughening, patterning, chemical modification, and surface modification for biomolecule and drug delivery.

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“…[42][43][44] The biocompatibility of specific polymer-coated stents has been reviewed elsewhere. 45,46 Drug-eluting stents offer theoretical advantages over systemic pharmacotherapy, such as higher drug concentrations at the site of stent deployment and minimal systemic side effects. …”

mentioning

confidence: 99%

Coated Stents for the Prevention of Restenosis: Part I

2002

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O ver the past decade, the use of endoluminal metallic stents has become common practice during percutaneous coronary intervention (PCI), especially after clinical trials showed evidence of decreased restenosis rates when compared with balloon angioplasty alone. [1][2][3] Although stents significantly reduce restenosis when compared with balloon angioplasty, restenosis rates in patients who receive stents are still 20% to 40% at 6 months. [1][2][3][4][5][6] Recently, the concept of using stents coated with agents that could potentially inhibit neointimal hyperplasia has emerged. These agents include biocompatible materials, anticoagulants, corticosteroids, and antimitotic agents. This 2-part article reviews animal studies, human observational studies, and results from randomized clinical trials investigating coated stents. Part I discusses the pathophysiology of in-stent restenosis, as well as animal studies investigating coated stents. Part II discusses human studies investigating coated stents. Pathophysiology of In-Stent RestenosisIn-stent restenosis is primarily due to neointimal hyperplasia. [7][8][9][10][11][12][13] Vessel injury by an angioplasty balloon or stent struts leads to the activation of platelets and mural thrombus formation. [13][14][15][16] The presence of vascular injury, mural thrombus, and a metallic foreign body activates circulating neutrophils and tissue macrophages. 12,13,17,18 These cellular elements release cytokines and growth factors that activate smooth muscle cells. 19 -23 Upregulation and expression of genes such as c-myc that regulate cell division ensues, leading to cell proliferation. 24,25 Production of matrix metalloproteinases is also upregulated, leading to remodeling of the extracellular matrix, and initiating smooth muscle cell migration. 26 -28 The end result of this cascade of events is the uncontrolled proliferation of smooth muscle cells around the vessel intima and the deposition of extracellular matrix material, which often lead to significant luminal narrowing 3 to 6 months after PCI (Figure 1). Coated StentsThe systemic administration of a variety of agents has not had a significant impact on post-PCI restenosis rates. 29 -34 Although there is some evidence that controlling mural thrombus formation may decrease neointimal hyperplasia, [35][36][37] antiplatelet agents have not reliably resulted in reductions in restenosis rates in clinical trials. 29,30 Similarly, the systemic administration of corticosteroids aimed at controlling the inflammatory process has not shown decreased restenosis rates. 31 The lack of effect of systemically administered agents may be due to inadequate drug concentrations at the site of stent insertion. The limited success of these agents in decreasing rates of in-stent restenosis, coupled with side effects, prompted the development of coated stents.Stent coatings can be divided into 2 categories, biocompatible materials and drug-eluting coatings (Table 1). Biocompatible materials currently under investigation are thought to be less th...

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Role of polymers in improving the results of stenting in coronary arteries

Cited by 104 publications

References 45 publications

Use of blends of bioabsorbable poly(L-lactic acid)/poly(hydroxybutyrate- co-hydroxyvalerate) as surfaces for Vero cell culture

Use of blends of bioabsorbable poly(L-lactic acid)/poly(hydroxybutyrate- co-hydroxyvalerate) as surfaces for Vero cell culture

A Survey of Surface Modification Techniques for Next-Generation Shape Memory Polymer Stent Devices

Coated Stents for the Prevention of Restenosis: Part I

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