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Roopmani P, Sethuraman S, Satheesh S, Maheswari Krishnan U. The metamorphosis of vascular stents: passive structures to smart devices. RSC Adv 2016. [DOI: 10.1039/c5ra19109b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The role of nanotechnology enabled techniques in the evolution of vascular stents.
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Affiliation(s)
- Purandhi Roopmani
- Centre for Nanotechnology and Advanced Biomaterials (CeNTAB)
- School of Chemical and Biotechnology
- SASTRA University
- Thanjavur-613 401
- India
| | - Swaminathan Sethuraman
- Centre for Nanotechnology and Advanced Biomaterials (CeNTAB)
- School of Chemical and Biotechnology
- SASTRA University
- Thanjavur-613 401
- India
| | - Santhosh Satheesh
- Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER)
- Department of Cardiology
- Pondicherry-605 006
- India
| | - Uma Maheswari Krishnan
- Centre for Nanotechnology and Advanced Biomaterials (CeNTAB)
- School of Chemical and Biotechnology
- SASTRA University
- Thanjavur-613 401
- India
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2
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Synthesis and characterization of curcumin segmented polyurethane with induced antiplatelet activity. JOURNAL OF POLYMER RESEARCH 2015. [DOI: 10.1007/s10965-015-0824-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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3
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In situcoronary stent paving by Pluronic F127-alginate gel blends: Formulation and erosion tests. J Biomed Mater Res B Appl Biomater 2015; 104:1013-22. [DOI: 10.1002/jbm.b.33425] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 03/07/2015] [Accepted: 03/20/2015] [Indexed: 11/07/2022]
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4
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O'Connell BM, Cunnane EM, Denny WJ, Carroll GT, Walsh MT. Improving smooth muscle cell exposure to drugs from drug-eluting stents at early time points: a variable compression approach. Biomech Model Mechanobiol 2013; 13:771-81. [PMID: 24101254 DOI: 10.1007/s10237-013-0533-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 09/22/2013] [Indexed: 11/29/2022]
Abstract
The emergence of drug-eluting stents (DES) as a viable replacement for bare metal stenting has led to a significant decrease in the incidence of clinical restenosis. This is due to the transport of anti-restenotic drugs from within the polymer coating of a DES into the artery wall which arrests the cell cycle before restenosis can occur. The efficacy of DES is still under close scrutiny in the medical field as many issues regarding the effectiveness of DES drug transport in vivo still exist. One such issue, that has received less attention, is the limiting effect that stent strut compression has on the transport of drug species in the artery wall. Once the artery wall is compressed, the stents ability to transfer drug species into the arterial wall can be reduced. This leads to a reduction in the spatial therapeutic transfer of drug species to binding sites within the arterial wall. This paper investigates the concept of idealised variable compression as a means of demonstrating how such a stent design approach could improve the spatial delivery of drug species in the arterial wall. The study focused on assessing how the trends in concentration levels changed as a result of artery wall compression. Five idealised stent designs were created with a combination of thick struts that provide the necessary compression to restore luminal patency and thin uncompressive struts that improve the transport of drugs therein. By conducting numerical simulations of diffusive mass transport, this study found that the use of uncompressive struts results in a more uniform spatial distribution of drug species in the arterial wall.
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Affiliation(s)
- Barry M O'Connell
- Centre for Applied Biomedical Engineering (CABER), Department of Mechanical, Aeronautical and Biomedical Engineering and The Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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5
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6
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Buehler M, Molian P. Nanosecond Laser Induced Periodic Surface Structures on Drug Elution Profiles in Stents. J Med Device 2012. [DOI: 10.1115/1.4006539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Drug-eluting stents (DESs) have profoundly affected the field of interventional cardiology as a transformative technology by dramatically reducing the problem of in-stent restenosis. However, the development of adverse, late stent thrombosis (LST) raises the question of the safety profile of the DES. The aim of the study is to develop better DESs that can increase the amount of drug (sirolimus) loading while slowing down the drug release rate and potentially eliminating the polymer, all of which are expected to aid in the prevention of LST. Nanosecond pulsed laser texturing of Nitinol stent surfaces was first performed and the surface topography was analyzed using an optical profilometer. The results showed that the surface texture parameters such as surface area ratio, its roughness, volume of fluid retained per unit area, and mean valley slope suitable for drug adhesion, retention, and elution were significantly increased due to laser texturing. Subsequently, the drug elution profiles were studied for four different types of stents: laser-textured and untreated stents coated with the drug only and the drug-polymer. Laser texturing reduced the cumulative sirolimus release from 73% to 25% in drug only coated stents and from 93% to 45% in drug-polymer coated stents and showed promise for applying polymer-free drug coatings on the DES.
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Affiliation(s)
| | - Pal Molian
- Laboratory for Lasers, MEMS and Nanotechnology, Department of Mechanical Engineering, Iowa State University, Ames, IA 50011
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7
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Luo LL, Wang GX, Li YL, Yin TY, Jiang T, Ruan CG. Layer-by-layer assembly of chitosan and platelet monoclonal antibody to improve biocompatibility and release character of PLLA coated stent. J Biomed Mater Res A 2011; 97:423-32. [DOI: 10.1002/jbm.a.33066] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2010] [Revised: 11/19/2010] [Accepted: 01/04/2011] [Indexed: 11/12/2022]
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8
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Yang Y, Lai Y, Zhang Q, Wu K, Zhang L, Lin C, Tang P. A novel electrochemical strategy for improving blood compatibility of titanium-based biomaterials. Colloids Surf B Biointerfaces 2010; 79:309-13. [PMID: 20466524 DOI: 10.1016/j.colsurfb.2010.04.013] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 04/14/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
Abstract
A controllable fabrication of superhydrophobic surface on titanium biomedical implants was successfully developed to improve the blood compatibility and anti-coagulation performance of biomedical implants. The electrochemical anodization was employed to form a layer of TiO(2) nanotubes on the titanium substrate, and then a hydrophobic monolayer was self-assembled on the nanotube surface. The morphology and wettability of the nanotube arrays were investigated by scanning electron microcopy and water drop contact angle measurement, respectively. From the in vitro blood compatibility evaluation, it was observed that not only very few of platelets were attached onto the superhydrophobic surface, but also the attached platelets were not activated in this condition. Comparatively, a large number of platelets adhered and spread out on both the bare titanium substrate and the superhydrophilic surface which was obtained by exposing the TiO(2) nanotubes under a UV irradiation. The results indicated that the superhydrophobic TiO(2) nanotube layers exhibited excellent blood compatibility and remarkable performance in preventing platelets from adhering to the implant surface. Therefore, the construction of superhydrophobic surface on biomedical implants could pave a way to improve the blood compatibility of the biomedical devices and implants.
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Affiliation(s)
- Yun Yang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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Wu M, Kleiner L, Tang FW, Hossainy S, Davies MC, Roberts CJ. Surface characterization of poly(lactic acid)/everolimus and poly(ethylene vinyl alcohol)/everolimus stents. Drug Deliv 2010; 17:376-84. [DOI: 10.3109/10717541003762847] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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O'Connell BM, McGloughlin TM, Walsh MT. Factors that affect mass transport from drug eluting stents into the artery wall. Biomed Eng Online 2010; 9:15. [PMID: 20214774 PMCID: PMC2854105 DOI: 10.1186/1475-925x-9-15] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 03/09/2010] [Indexed: 01/12/2023] Open
Abstract
Coronary artery disease can be treated by implanting a stent into the blocked region of an artery, thus enabling blood perfusion to distal vessels. Minimally invasive procedures of this nature often result in damage to the arterial tissue culminating in the re-blocking of the vessel. In an effort to alleviate this phenomenon, known as restenosis, drug eluting stents were developed. They are similar in composition to a bare metal stent but encompass a coating with therapeutic agents designed to reduce the overly aggressive healing response that contributes to restenosis. There are many variables that can influence the effectiveness of these therapeutic drugs being transported from the stent coating to and within the artery wall, many of which have been analysed and documented by researchers. However, the physical deformation of the artery substructure due to stent expansion, and its influence on a drugs ability to diffuse evenly within the artery wall have been lacking in published work to date. The paper highlights previous approaches adopted by researchers and proposes the addition of porous artery wall deformation to increase model accuracy.
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Affiliation(s)
- Barry M O'Connell
- Centre for Applied Biomedical Engineering Research, Department of Mechanical and Aeronautical Engineering and the Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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11
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Sarısözen C, Arıca B, Orman MN, Hıncal AA, Çalış S. Optimization of prednisolone acetate-loaded chitosan microspheres using a 23factorial design for preventing restenosis. Drug Deliv 2010; 17:178-86. [DOI: 10.3109/10717541003667780] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Wang GX, Luo LL, Yin TY, Li Y, Jiang T, Ruan CG, Guidoin R, Chen YP, Guzman R. Ultrasonic atomization and subsequent desolvation for monoclonal antibody (mAb) to the glycoprotein (GP) IIIa receptor into drug eluting stent. J Microencapsul 2010. [DOI: 10.3109/02652040903046798] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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O’Connell BM, Walsh MT. Demonstrating the Influence of Compression on Artery Wall Mass Transport. Ann Biomed Eng 2010; 38:1354-66. [DOI: 10.1007/s10439-010-9914-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 01/05/2010] [Indexed: 10/20/2022]
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14
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In vitro andin vivo characterization of a coronary stent coated with an elastic biodegradable polymer for the sustained release of paclitaxel. Macromol Res 2009. [DOI: 10.1007/bf03218654] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Shedden L, Oldroyd K, Connolly P. Current issues in coronary stent technology. Proc Inst Mech Eng H 2009; 223:515-24. [PMID: 19623905 DOI: 10.1243/09544119jeim541] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Coronary artery stents have become the medical device of choice for the treatment of coronary artery disease. Since their introduction in 1987, significant advances in stent technology have taken place. A major objective of these developments was the reduction of in-stent restenosis, the formation of neointimal tissue inside the stent triggered by vessel injury and the inflammatory response, which results in renarrowing of the coronary artery. Improvements in strut configuration, thickness, and materials have enhanced deliverability and reduced vessel damage. Currently available drug-eluting stents release drugs that reduce neointimal formation through the arrest of cell proliferation. Drug-eluting stents have significantly reduced rates of in-stent restenosis. However, concerns have been raised with respect to their long-term safety, particularly in relation to the occurrence of late thrombosis. The post-procedural monitoring of stent-related complications is also of interest, including the relative suitability of invasive techniques such as angiography and intravascular ultrasound, and non-invasive techniques such as computed tomography and magnetic resonance imaging scanning. This paper reviews the current issues in stent technology.
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Affiliation(s)
- L Shedden
- Department of Bioengineering, University of Strathclyde, Glasgow, UK
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16
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Huang Y, Venkatraman SS, Boey FYC, Umashankar PR, Mohanty M, Arumugam S. The short-term effect on restenosis and thrombosis of a cobalt-chromium stent eluting two drugs in a porcine coronary artery model. J Interv Cardiol 2009; 22:466-78. [PMID: 19627432 DOI: 10.1111/j.1540-8183.2009.00489.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The aim of this article was to study the effect of dual drug-eluting stent (DES) on both restenosis and thrombosis in a porcine coronary artery model. This study reports on the use of two drugs coated on the stent to simultaneously minimize both restenosis and thrombosis. The DES was prepared by spray coating a bare metal stent with a biodegradable polymer loaded with sirolimus and triflusal, to treat against restenosis and thrombosis, respectively. The two-layered dual drug-coated stent was characterized in vitro for surface properties before and after expansion, as well as for possible delamination by cross-sectioning the stent in vitro. In vivo animal studies (in a pig model) were then performed for acute thrombosis, inflammation, and restenosis. The results show a significant reduction in restenosis with a stent coated with both drugs compared with the controls (a bare metal stent, a sirolimus-coated, and a pure polymer-coated stent). The reduction in restenosis with a sirolimus/triflusal-eluting stent is associated with an inhibition of inflammation and thrombus formation, suggesting that such dual DES have a role to play for the treatment of coronary artery diseases.
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Affiliation(s)
- Yingying Huang
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
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17
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Nanoscale mechanical measurement determination of the glass transition temperature of poly(lactic acid)/everolimus coated stents in air and dissolution media. Eur J Pharm Sci 2009; 36:493-501. [DOI: 10.1016/j.ejps.2008.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 11/21/2008] [Accepted: 12/01/2008] [Indexed: 11/18/2022]
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18
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Thomadsen BR, Williamson JF, Rivard MJ, Meigooni AS. Anniversary Paper: Past and current issues, and trends in brachytherapy physics. Med Phys 2008; 35:4708-23. [DOI: 10.1118/1.2981826] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Abstract
Titanium oxides films were deposited on tensile sample and vascular stents made of 316L stainless steel by unbalanced magnetron sputtering. The effects of structures, deposition temperature, Ti interlayer and thickness on the adhesion of titanium oxide films were investigated by tensile tests. The results revealed that the structure of the Ti-O films affect their adhesion dramatically. TiO film is brittle and fragile, lacking ability of deformation. Therefore its adhesion was worse than that of TiO2 film. The higher substrate temperature was helpful to improve adhesion of film, the adhesion of the TiO film deposited at 673K was better than those of the TiO films deposited at 323K and 473K. The adhesion of the TiO film with Ti interlayer was better than the one without interlayer. The introduction of Ti interlayer was beneficial to adhesion of film. The adhesion of thinner TiO2 film was better than that of thicker one. TiO2 film deposited on stents had good adhesion. After expansion, the film didn’t crack and peel off. TiO2 film has potential application on the vascular stents for improving its blood compatibility.
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McLucas E, Gallagher H, Rochev Y, Carroll WM, Gorelov A, Smith TJ. Global gene expression analysis of the effects of vinblastine on endothelial cells, when eluted from a thermo-responsive polymer. J Biomed Mater Res A 2006; 79:246-53. [PMID: 16817212 DOI: 10.1002/jbm.a.30756] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In-stent restenosis remains a significant problem associated with bare metal stents. This drawback has prompted research into improving stent design and the development of novel coatings, including drug-eluting stents. A number of drug-eluting stents are currently on the market; however, the success rate of these stents in complex situations has been found to be quite low. Thus, there remains potential for the development of more suitable drug-eluting stents. The aims of this study were to use a thermoresponsive polymer to develop a system to locally deliver vinblastine, an antimitotic agent currently used as an anticancer drug, and in addition, assess the effects of this drug at the gene expression level in vitro. An N-isopropylacrylamide/N-tert-butylacrylamide (NiPAAm/NtBAAm) copolymer solution in the ratio 65:35 was prepared and appropriate volumes of vinblastine were added to generate two final drug concentrations of 22 nanomoles/film or 0.022 nanomoles/film. Stainless steel discs (316) were coated with the copolymer solution or this solution containing drug. Human endothelial cells were cultured on collagen type 1 gels and then incubated with the coated discs for 24 h. Gene expression studies using oligonucleotide microarray analysis and quantitative RT-PCR were then performed. Microarray analysis revealed that vinblastine causes the differential expression of a range of genes involved in a variety of different functions, including cell cycle and apoptosis. The changes in expression of some of these genes culminate in cell cycle arrest and apoptotic pathways.
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Affiliation(s)
- E McLucas
- National Centre for Biomedical Engineering Science, National University of Ireland, Galway, Ireland
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Pan CJ, Tang JJ, Weng YJ, Wang J, Huang N. Preparation, characterization and anticoagulation of curcumin-eluting controlled biodegradable coating stents. J Control Release 2006; 116:42-9. [PMID: 17046093 DOI: 10.1016/j.jconrel.2006.08.023] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 08/10/2006] [Accepted: 08/29/2006] [Indexed: 11/24/2022]
Abstract
Curcumin is pharmaceutically active in many ways, having properties including anticoagulation, anti-proliferation, anti-inflammatory, and may be used to fabricate drug-eluting stents to treat in-stent restenosis after stent implantation. Here we describe our investigations of curcumin-eluting PLGA coatings formed using the biodegradable polymer PLGA (polylactic acid-co-glycolic acid) as drug carrier and uniformly fabricated on the surface of 316L stainless steel stents by an ultrasonic spray method. Three doses were explored--low dose ( approximately 140 microg per stent or 115 microg/cm(2)), moderate dose ( approximately 280 microg per stent or 230 microg/cm(2)), and high dose ( approximately 490 microg per stent or 408 microg/cm(2)). Pre- and post-expansion morphologies of the stent coating were examined by optical microscopy (OM) and scanning electron microscopy (SEM), indicating that the coating not only was very smooth and uniform but also had the ability to withstand the compressive and tensile strains imparted without cracking from the stent during the expansion process. Atomic force microscopy (AFM) images indicated the topography of the PLGA-only and moderate dose curcumin-eluting stent that showed an average roughness below 1 nm; no drug particles could be seen on the stent surface, indicating that curcumin can be mixed with PLGA at the molecular level using an ultrasonic atomization spray method. The structure of the coating films was characterized by Fourier Transform Infrared (FTIR) spectroscopy and X-ray electron spectroscopy (XPS), with results suggesting that there was no chemical reaction between curcumin and the drug. The results of in vitro measurements of drug release from curcumin-eluting stents showed that all the curcumin-eluting stents studied exhibited a nearly linear sustained-release profile with no significant burst releases within the measurement period. The in vitro anticoagulation behavior of curcumin-eluting stents was investigated by static platelet adhesion and APTT (activated partial thromboplastin time) tests, revealing that the anticoagulation properties of curcumin-eluting stents are superior to those for stainless steel stents and PLGA-only-coated stents. The anticoagulation behavior of curcumin stents improved significantly as the drug dose was increased.
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Affiliation(s)
- Ch J Pan
- Key Laboratory for Advanced Technologies of Materials, The Ministry of Education, Southwest Jiaotong University, Chengdu 610031, China
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Wu CH, Pan JS, Chang WC, Hung JS, Mao SJT. The molecular mechanism of actinomycin D in preventing neointimal formation in rat carotid arteries after balloon injury. J Biomed Sci 2005; 12:503-12. [PMID: 15959627 DOI: 10.1007/s11373-005-6900-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 05/02/2005] [Indexed: 11/24/2022] Open
Abstract
The pathological mechanism of restenosis is primarily attributed to excessive proliferation of vascular smooth muscle cells (SMC). Actinomycin D has been regarded as a potential candidate to prevent balloon injury-induced neointimal formation. To explore its molecular mechanism in regulating cell proliferation, we first showed that actinomycin D markedly reduced the SMC proliferation via the inhibition of BrdU incorporation at 80 nM. This was further supported by the G1-phase arrest using a flowcytometric analysis. Actinomycin D was extremely potent with an inhibitory concentration IC50 at 0.4 nM, whereas the lethal dose LD50 was at 260 microM. In an in vivo study, the pluronic gel containing 80 nM and 80 microM actinomycin D was applied topically to surround the rat carotid adventitia; the thickness of neointima was substantially reduced (45 and 55%, respectively). The protein expression levels of proliferating cell nuclear antigen (PCNA), focal adhesion kinase (FAK), and Raf were all suppressed by actinomycin D. Extracellular signal-regulated kinases (Erk) involved in cell-cycle arrest were found to increase by actinomycin D. These observations provide a detailed mechanism of actinomycin D in preventing cell proliferation thus as a potential intervention for restenosis.
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Affiliation(s)
- C H Wu
- Department of Pharmacology, School of Medicine, China Medical University, 91 Hsueh-Shieh Road, Taichung, 404, Taiwan.
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Angiolillo DJ, Sabaté M, Jiménez-Quevedo P, Alfonso F, Galván C, Fernández JM, Hernandez-Antolin R, Escaned J, Bañuelos C, Moreno R, Macaya C. Intracoronary brachytherapy following drug-eluting stent failure. It's still not time to hang up the spikes! ACTA ACUST UNITED AC 2004; 4:171-5. [PMID: 15321053 DOI: 10.1016/j.carrad.2004.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Accepted: 02/02/2004] [Indexed: 11/29/2022]
Abstract
Drug-eluting stents (DES) have significantly reduced the incidence of restenosis. Although the results obtained with these novel antiproliferative devices are encouraging, recent reports have shown that DES are not completely immune from restenosis. Therefore, the broad use of DES has inevitably led to a major issue: treatment of DES failure. Intracoronary brachytherapy (IBT) represents an important advancement for treatment of in-stent restenosis (ISR) and has led to important pathophysiological insight on the restenotic process. To date, IBT, when properly used, still represents the gold standard for treatment of ISR. However, experience with IBT is for treatment of ISR occurring with bare metal stents (BMS). Whether IBT may be used with the same safety and efficacy profile as an adjunctive treatment for ISR following DES implantation is still unknown. In this article, we report the outcome of a series of patients with DES failure treated with IBT. IBT for treatment of DES failure was shown to be both safe and efficient and, therefore, until ISR exists, IBT still remains an important player in this growing and even more challenging setting.
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Affiliation(s)
- Dominick J Angiolillo
- Interventional Cardiology Unit, San Carlos University Hospital-planta 2N, Plaza Cristo Rey s/n, 28040 Madrid, Spain
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Orford JL, Lerman A, Holmes DR. Routine intravascular ultrasound guidance of percutaneous coronary intervention. J Am Coll Cardiol 2004; 43:1335-42. [PMID: 15093863 DOI: 10.1016/j.jacc.2003.12.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2003] [Revised: 12/08/2003] [Accepted: 12/09/2003] [Indexed: 11/20/2022]
Abstract
Intravascular ultrasound (IVUS) has played an integral role in the evolution of interventional cardiology. However, routine IVUS guidance of coronary stent implantation is not supported by a critical reappraisal of the available evidence. Although there is a trend toward a benefit with respect to target lumen revascularization favoring IVUS-guided coronary stent implantation, it is likely that this effect is driven by improved outcomes in small vessels, long coronary stenoses, and possibly saphenous vein graft interventions. No consistent trend in the incidence of death or myocardial infarction is apparent. Furthermore, the safety, efficacy, and effectiveness of IVUS should be taken into account when considering the goals, risks, benefits, and alternatives to such a treatment strategy.
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Affiliation(s)
- James L Orford
- Department of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Kuchulakanti P, Waksman R. Therapeutic Potential of Oral Antiproliferative Agents in the Prevention of Coronary Restenosis. Drugs 2004; 64:2379-88. [PMID: 15481997 DOI: 10.2165/00003495-200464210-00001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The treatment of coronary artery disease has reached many milestones - from balloon angioplasty to drug-eluting stents. The last decade witnessed the revolution of bare metal stents with new designs, alloys and strut thicknesses. Yet restenosis, the aphorismic 'Achilles heel', remains to be conquered. The restenosis rates with balloon angioplasty alone are 30-40% and are reduced to 20-30% with stents. Although intravascular brachytherapy proved to be a durable and safely used technique to treat in-stent restenosis, clinical event rates were not reduced to single digits.Drug-eluting stents are showing positive results in this direction, but it is too early to predict their efficacy in various subsets of lesions. With the increased usage of these stents, there are reports of problems such as late stent malapposition, subacute and late thromboses, and aneurysm formations due to the vessel toxicity associated with this method of treatment. Furthermore, when multivessel stenting is considered, the cost of drug-eluting stents is a significant problem given the fact that these are no longer 'zero restenosis' devices. There is a definite need for a simple, safe and durable solution to restenosis. Oral agents are an alternative delivery strategy that can target multiple coronary lesions, which are targets for catheter-based revascularisation with any approved metal stent and with potentially lower cost. Although oral agents have been an interesting option to treat restenosis and several agents have been tested in trials since the 1980s, the results were disappointing. The development of devices such as intravascular ultrasound has led to a greater understanding of restenosis mechanisms, and the focus on pathophysiological mechanisms, which centred mainly on platelets, growth factors and lipids, has changed to inflammation, endothelium and smooth muscle cell proliferation.Accordingly, the targets of pharmaceutical agents have shifted from platelets to cell cycle inhibition, smooth muscle cell proliferation and migration, synthesis of extra cellular matrix, and inflammatory mediators. Initial encouraging results with oral drugs such as cilostazol, sirolimus (rapamycin) and thiazolidinediones indicate a definite place for this strategy to reduce restenosis. A desirable oral agent would be anti-inflammatory, inhibit smooth muscle cell migration and proliferation, promote endothelial growth, and be well tolerated and free from significant adverse effects. It may be useful to start with a high loading dose before stent implantation and then follow with a short-term lower maintenance dose. Future trials should be aimed at finding an ideal agent, effective loading dose, maintenance dose and optimum duration of therapy.
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Affiliation(s)
- Pramod Kuchulakanti
- Division of Cardiology, Washington Hospital Center, Washington, DC 20010, USA
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