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Effect of resveratrol combined with atorvastatin on re-endothelialization after drug-eluting stents implantation and the underlying mechanism. Life Sci 2020; 245:117349. [PMID: 31981632 DOI: 10.1016/j.lfs.2020.117349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 11/20/2022]
Abstract
AIMS To explore whether the combination of atorvastatins and resveratrol is superior to each individual drug alone regarding re-endothelialization after drug-eluting stents (DESs) implantation. MATERIALS AND METHODS Ninety-four rabbits were randomized into control, atorvastatin, resveratrol, and combined medication groups. Abdominal aorta injury was induced via ballooning, followed by DES implantation. Neointimal formation and re-endothelialization after stent implantation were assessed via optical coherence tomography and scanning electron microscopy. The effects of resveratrol and atorvastatin on bone marrow-derived mesenchymal derived stem cells (BMSCs) were assessed. KEY FINDINGS Compared with the findings in the resveratrol and atorvastatin groups, the neointimal area and mean neointimal thickness were greater in the combined medication group, which also exhibited improved re-endothelialization. Compared with the effects of monotherapy, combined treatment further protected BMSCs against rapamycin-induced apoptosis and improved cell migration. Combined medication significantly upregulated Akt, p-Akt, eNOS, p-eNOS, and CXCR4 expression in BMSCs compared with the effects of monotherapy, and these effects were abolished by the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002. SIGNIFICANCE The combination of atorvastatin and resveratrol has the potential of accelerating re-endothelialization after stent implantation, reducing the risk of thrombosis and improving the safety of DESs.
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Tan LP, Venkatraman SS, Joso JFD, Boey FYC. Collapse pressures of bilayered biodegradable stents. J Biomed Mater Res B Appl Biomater 2006; 79:102-7. [PMID: 16544311 DOI: 10.1002/jbm.b.30518] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Biodegradable helicoidal stent prototypes made up of layers of poly-L-lactic acid (PLLA) and poly(L-lactic-co-glycolic acid) (PLGA) polymers were fabricated by temperature conditioning the stents at different stages of fabrication. The process incorporated elastic memory, or self-expandability in the stent, which is desirable to minimize stent recoil. The collapse pressures of such stents were studied, with and without in vitro degradation. The effects of thickness and the composition of each layer on the collapse pressure were modeled using the simple series model. Results of the in vitro studies for over 3 months showed that collapse pressure of the stents depended mainly on the degradation and other side-effects brought about by the degradation of different polymer compositions. Generally, the trend is dominated by the thicker of the two layers that were used to form the stents.
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Affiliation(s)
- L P Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798.
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3
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Abstract
Biodegradable stent prototypes were produced from poly L-lactic acid polymers with different molecular weights. The effects of molecular weight, drug incorporation and stent design on the collapse pressure of the stents were evaluated. While molecular weights did not show a significant effect on the collapse pressure of the stents, drug incorporation at high percentage decreased the collapse pressure of the stents substantially. Cryogenic fracture surfaces showed significant drug agglomeration as the concentration increased. The design of the stent was also found to a have significant effect on the collapse pressure. The stent produced from the same material has a higher collapse pressure when the load bearing surface area is increased.
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Affiliation(s)
- Subbu Venkatraman
- School of Materials Engineering, Nanyang Technological University, N4.1-1-30 Nanyang Avenue, 639798, Singapore, Singapore.
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Sirlin CB, Lee YZ, Girard MS, Peterson TM, Steinbach GC, Baker KG, Mattrey RF. Contrast-enhanced B-mode US angiography in the assessment of experimental in vivo and in vitro atherosclerotic disease. Acad Radiol 2001; 8:162-72. [PMID: 11227645 DOI: 10.1016/s1076-6332(01)90133-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
RATIONALE AND OBJECTIVES This study was performed to (a) test the hypothesis that filling the arterial lumen with echoes at B-mode ultrasound (US) enables the assessment of wall and luminal abnormalities and (b) compare contrast material-enhanced B-mode US with color and power Doppler US angiography. MATERIALS AND METHODS Atherosclerotic lesions were created in 14 rabbit aortas and imaged with color Doppler and B-mode US before and after the intravenous administration of 0.3 mL of AF0150, a US contrast agent. In addition, four replicas of diseased human carotid arteries were immersed in a tissue-mimicking phantom and imaged with B-mode and color and power Doppler US before and after the administration of 1 mL of AF0150 per liter of porcine blood. Radiopaque plastic casts of the rabbit aortas and contact radiographs of the plastic replicas served as standards. RESULTS Although color and power Doppler US allowed immediate localization of the lumen, precise estimation of stenoses and reliable visualization of surface irregularities were not possible. After AF0150 administration, angiogram-like images of the lumen were created with B-mode US, allowing rapid assessment of the entire vessel lumen and wall. Consequently, luminal stenoses were more accurately measured than with unenhanced B-mode US (r2 = 0.94, P < .0001 vs r2 = 0.21, P = .25) or Doppler (r2 = 0.42, P < .03). In addition, plaques and ulcerations were visible only with contrast-enhanced B-mode US. CONCLUSION Microbubbles fill the arterial lumen with echoes at B-mode US, creating an angiogram-like image. The ability to visualize the inner and outer surfaces of the vascular wall improved the evaluation of luminal and wall abnormalities.
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Affiliation(s)
- C B Sirlin
- Department of Radiology, University of California, San Diego Medical Center, USA
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Vernhet H, Juan JM, Demaria R, Oliva-Lauraire MC, Senac JP, Dauzat M. Acute changes in aortic wall mechanical properties after stent placement in rabbits. J Vasc Interv Radiol 2000; 11:634-8. [PMID: 10834497 DOI: 10.1016/s1051-0443(07)61618-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
PURPOSE To evaluate mechanical property changes after endovascular stent placement in small-diameter arteries. MATERIALS AND METHODS Self-expanding stents (Wallstent) were placed in the infrarenal aorta of five New Zealand White rabbits via a surgical right femoral approach. Blood pressure changes (deltaP) were monitored in the aorta. Blood flow velocity was measured with a 20-MHz, pulsed Doppler probe (n = 4) to calculate the pulsatility index. Aortic diameter (dA) and diameter changes (delta(d)) were measured with a 20-MHz probe in echo-tracking mode. Diameter compliance (Cd) and distensibility coefficient (DC) were calculated as Cd = 2(delta)d/(delta)P and DC = 2delta(d)/delta(P)/dA. RESULTS Aortic diameter increased from 3.360 +/- 0.4033 mm to 4.020 +/- 0.3033 mm after stent placement at the stent level only. Compliance decreased from 77.644 +/- 24.306 mm kPa(-1) to 31.150 +/-8.245 x 10(-3) mm kPa(-1) at the stent level, and was then significantly lower than upstream (98.500 +/- 53.196 mm kPa(-1)) and down-stream (59.047 +/- 13.833 mm kPa(-1)). There was no significant change in pulsatility index. CONCLUSIONS Endovascular stent placement produces a significant decrease in arterial wall compliance of the rabbit abdominal aorta.
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Affiliation(s)
- H Vernhet
- Laboratory of Cardiovascular Physiology, Montpellier I University, Faculty of Medicine, Nimes, France
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6
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Froelich JJ, Alfke H, Wilke A, Ramaswamy A, Barth KH, Hoppe M, Wagner HJ, Klose KJ. Effects of nitinol Strecker stent placement on vascular response in normal and stenotic porcine iliac arteries. J Vasc Interv Radiol 1999; 10:329-38. [PMID: 10102199 DOI: 10.1016/s1051-0443(99)70039-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
PURPOSE This experimental study was conducted to evaluate neointimal thickness, lumen diameters, and histologic changes in normal and stenotic porcine iliac arteries following placement of self-expanding nitinol Strecker stents. MATERIALS AND METHODS Neointimal trauma causing slight vascular stenosis was induced unilaterally within external iliac arteries of 12 swines by means of endothelial abrasion and high cholesterol diet. Nitinol Strecker stents were placed within the stenotic and the normal contralateral vascular segments. For histopathologic evaluation, the pigs were killed 12 or 24 weeks after stent placement and luminal diamters were evaluated angiographically. RESULTS Excluding one occlusion, 15% narrowing of the lumen diameter was induced unilaterally (P = .002). Initial luminal gain after stent placement was greater for stenotic than for normal arteries. The amount of neointima thickness was not different between stenotic and normal vessels (P > .05). Comparing vascular diameters before stent placement and at follow-up, luminal loss due to neointima proliferation was 22% within normal arteries (P = .0002), while a luminal gain by 15% was found within the stenotic arteries (P = .008). Maturation of neointima and endothelial coverage were complete after 24 weeks. CONCLUSIONS Even though nitinol Strecker stents induce excessive neointimal proliferation, stenotic arteries seem to profit from great early luminal gain resulting in 15% of vascular expansion at follow-up while slight stenosis is induced within normal iliac arteries.
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Affiliation(s)
- J J Froelich
- Department of Radiology, Philipps-University Hospital, Marburg, Germany
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Liermann D, Kirchner J, Bauernsachs R, Schopohl B, Böttcher HD. Brachytherapy with iridium-192 HDR to prevent from restenosis in peripheral arteries. An update. Herz 1998; 23:394-400. [PMID: 9816526 DOI: 10.1007/bf03043605] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The use of stents does not appreciably improve restenosis (usually resulting from intimal hyperplasia) as compared to percutaneous transluminal angioplasty (PTA) alone. The development of small-caliber probes for afterloading therapy in the biliary tract allowed us to use these for therapy in the vascular system. Using a special 9 F catheter, exact measurement of the length of the stented vascular segment and of the insertion length of the afterloading probe could be reproducibly performed. We used a Nucletron (Micro) Selectron HDR planning system version 10.10 for exact calculation, monitoring, and control of the afterloading procedure. Our source was iridium 192 (10 Ci) with a diameter of 1.1 mm. The program controls and monitors the insertion and removal of the iridium probe from the source into the special catheter through to the tip, and monitors the irradiation duration. The exposure time was around 200 seconds for a surface dose of 12 Gy. To date, a total of 40 patients have been treated with endovascular afterloading. All patients suffered from clinically relevant reocclusions or restenoses in stented vascular segments of the superficial femoral artery following successful PTA or laser treatment, within 6 to 8 months after the last therapy. In all patients it was possible to perform re-PTA treatment without remaining residual stenoses in the stented region. The additional time required as compared to PTA alone was approximately 45 minutes with most of this time spending for transportation between the cath lab and afterloading room. The follow-up period of the 40 patients ranged from 4 months to 71/2 years. In 33 patients, there was no deterioration of the clinical stage and no restenosis. One patient suffered from an acute thrombosis approximately 3 months after stent implantation, another patient had a stenosis 3 cm above the stented vascular segment 12 months after irradiation treatment. Follow-up examinations have revealed no evidence of nerve lesions following irradiation therapy. The tissue surrounding the artery showed no change following irradiation therapy, either in the CT, color-coded Doppler, endovascular ultrasonic scan or MRI. No complaints of discomfort were reported during or after irradiation. With the exceptions mentioned above, there was no evidence of any complications.
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Affiliation(s)
- D Liermann
- Clinic of Radiology and Nuclear Medicine, Hospital of the Ruhr University Bochum, Germany.
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Vorwerk D, Redha F, Neuerburg J, Clerc C, G�nther RW. Neointima formation following arterial placement of self-expanding stents of different radial force: Experimental results. Cardiovasc Intervent Radiol 1994. [DOI: 10.1007/bf01102068] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Vorwerk D, Redha F, Neuerburg J, Clerc C, Günther RW. Neointima formation following arterial placement of self-expanding stents of different radial force: experimental results. Cardiovasc Intervent Radiol 1994; 17:27-32. [PMID: 8187129 DOI: 10.1007/bf00197911] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
PURPOSE Radial force delivered by self-expanding stents has been discussed as a factor affecting thickness of neointima formation. METHODS Two types of Wallstents were studied experimentally in vitro and in vivo. Due to an altered braiding angle of the stent filaments, one stent type (LS type) delivers half the radial force to the vascular wall than the conventional type. The radial force was evaluated in a compression-expansion test which related changes in stent length to the compressing force. Fourteen LS and 16 conventional stents were implanted into 15 femoropopliteal arteries of 10 dogs. Autopsy was performed after 4 weeks (14 stents) or 6 months (16 stents). RESULTS All stents remained patent over the follow-up period with no evidence of stenosis. Neointimal overgrowth was complete and smooth in all. Medial atrophy was a constant finding after placement of both types. Neointimal thickness did not exceed 100 microns after 4 weeks and 6 months and did not significantly differ between LS stents and conventional stents. CONCLUSION It is concluded that in normal dogs self-expanding stents of the Wallstent type do not induce neointimal buildup that exceeds 100 microns in the femoropopliteal artery. A reduced radial force was not found to result in reduced neointima formation.
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Affiliation(s)
- D Vorwerk
- Department of Diagnostic Radiology, University of Technology of Aachen, Germany
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Liermann D, Bottcher HD, Kollath J, Schopohl B, Strassmann G, Strecker EP, Breddin KH. Prophylactic endovascular radiotherapy to prevent intimal hyperplasia after stent implantation in femoropopliteal arteries. Cardiovasc Intervent Radiol 1994. [DOI: 10.1007/bf01102065] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Liermann D, Strecker EP, Peters J. The Strecker stent: indications and results in iliac and femoropopliteal arteries. Cardiovasc Intervent Radiol 1992; 15:298-305. [PMID: 1423390 DOI: 10.1007/bf02733954] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have implanted more than 100 Strecker stents in the iliac and femoral arteries. In iliac arteries, follow-up is available from 8 to 48 months (mean 20 months) and in peripheral arteries, from 8 to 32 months (mean 19 months). In iliac and proximal femoral arteries there was a patency rate of 98% (mean 20 months after stent implantation) whereas in peripheral arteries the patency rate was 70.8% (mean 19 months after stent implantation). Besides careful selection of patients, anticoagulation is very important for successful stenting. Because of the excellent results of stents in iliac vessels there is a wide range of good indications, including primary stenting after recanalization of occlusions. In contrast, stent implantation in peripheral vessels should be restricted to special cases such as acute dissection or reocclusion after successful recanalization.
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Affiliation(s)
- D Liermann
- Department of Radiology, Klinikum der J.W. Goethe Universität Frankfurt, Germany
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Abstract
Endovascular surgery is a new multidisciplinary field that applies the recently innovated techniques of angioscopy, intraluminal ultrasound, balloon angioplasty, laser, mechanical atherectomy, and stents. This field can be defined as a diagnostic and therapeutic discipline that uses catheter-based systems to treat vascular disease. As such, it integrates the subspecialties of vascular surgery, interventional radiology, interventional cardiology, and biomedical engineering for the common purpose of improving arterial hemodynamics. Endovascular surgery offers many potential benefits: long incisions are replaced with a puncture wound, the need for postoperative intensive care is significantly reduced, major cardiac and pulmonary complications from general anesthesia are side stepped, and the dollar savings could be dramatic as the need for intensive care unit and in-hospital stay diminishes. Despite these technological advancements, endovascular surgery is still in its infancy and currently has limited applications. This review provides an updated summary of endovascular surgery today and addresses some of the obstacles still preventing its widespread use.
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Affiliation(s)
- S S Ahn
- Section of Vascular Surgery, UCLA Center for the Health Sciences 90024
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Chuapetcharasopon C, Wright KC, Wallace S, Dobben RL, Gianturco C. Treatment of experimentally induced atherosclerosis in swine iliac arteries: a comparison of self-expanding and balloon-expanded stents. Cardiovasc Intervent Radiol 1992; 15:143-50. [PMID: 1628279 DOI: 10.1007/bf02735576] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Atherosclerosis was induced in 20 Hanford miniature swine. Subsequently, one iliac artery lesion in each of 16 pigs was stented with either a self-expanding (8 pigs) or a balloon-expanded (8 pigs) stent. Immediately after stent placement, 4 animals in each group were taken off the atherogenic diet and continued on normal chow for the remainder of the study. Four months after stents were placed, atherosclerosis and the mural changes associated with the stent were more clearly evident in the arteries of the pigs continued on the atherogenic diet. These pigs also exhibited significantly more neointimal proliferation. In addition, the arteries containing the balloon-expanded stents showed more extensive and complex intimal changes when compared with arteries with self-expanding stents. Although both stent designs were equally effective in maintaining vascular patency, the balloon-expanded stent was more traumatic to the vessel wall which resulted in a significantly greater neointimal thickness.
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Affiliation(s)
- C Chuapetcharasopon
- University of Texas M. D. Anderson Cancer Center, Department of Diagnostic Radiology, Houston
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Krupski WC, Bass A, Kelly AB, Hanson SR, Harker LA. Reduction in thrombus formation by placement of endovascular stents at endarterectomy sites in baboon carotid arteries. Circulation 1991; 84:1749-57. [PMID: 1914112 DOI: 10.1161/01.cir.84.4.1749] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Although antithrombotic therapies with aspirin, dipyridamole, and heparin have decreased thrombo-occlusive events, they have not abolished these complications. Endovascular mechanical support, first reported by Dotter in 1969, has been proposed as a means to reduce both acute and chronic vessel closure by providing a supporting framework for the disrupted and sometimes dissected arterial wall. METHODS AND RESULTS To determine the effects of placing self-expanding stainless steel wire endoprostheses on the accumulation of thrombus at sites of carotid artery endarterectomy we measured platelet deposition continuously for 90 minutes and at 24 and 48 hours by gamma camera imaging of autologous 111In-labeled platelets in six stented and nonstented endarterectomized baboons that received heparin but no antiplatelet agents. At nonstented endarterectomy sites 5.36 +/- 1.25 x 10(8), 4.78 +/- 0.98 x 10(8), and 4.55 +/- 0.81 x 10(8) platelets per cm were deposited at 30, 60, and 90 minutes, respectively. In contrast, stented endarterectomy sites accumulated 0.99 +/- 0.31 x 10(8), 0.66 +/- 0.33 x 10(8), and 0.80 +/- 0.36 x 10(8) platelets per cm at 30 minutes (p = 0.02), 60 minutes (p = 0.004), and 90 minutes (p = 0.002), respectively. Platelet deposition remained reduced at 24 and 48 hours in stented endarterectomized carotid arteries (ECAs) when assessed as a ratio between net radioactivity in the endarterectomized region versus whole blood radioactivity (p = 0.006 and p = 0.009, respectively). Both stented and nonstented ECAs remained patent acutely, although two of six nonstented ECAs occluded by 30 days. By comparison 11 of 14 nonstented ECAs remained patent in another group of control animals. Scanning electron microscopy of control and stented arteries at 30 days demonstrated equivalently confluent endothelium. CONCLUSIONS We postulate that endovascular stents reduce the thrombogenic effects of flap formation, tearing, dissection, and vasospasm in ECAs.
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Affiliation(s)
- W C Krupski
- Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322
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Serruys PW, Strauss BH, van Beusekom HM, van der Giessen WJ. Stenting of coronary arteries: has a modern Pandora's box been opened? J Am Coll Cardiol 1991; 17:143B-154B. [PMID: 2016472 DOI: 10.1016/0735-1097(91)90951-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Interventional cardiology has recently witnessed the growth of several alternatives to percutaneous transluminal angioplasty, including coronary stenting. Although stenting appears to be useful in treating abrupt closure after coronary angioplasty, its effectiveness in limiting the complex processes responsible for late restenosis is much less certain. Pathologic examination of stented human saphenous bypass grafts shows extensive deposits of platelets, fibrin and leukocytes along the stent wires within the 1st week and formation of a neointima of variable thickness after 3 months without evidence of foreign body reaction. The long-term effects of continuous barotrauma induced by the expanded stent remain unknown. It is difficult to assess the relative merits of the new devices, but stenting has several theoretic advantages. It seems less disruptive to the underlying architecture of the vessel wall and enjoys favorable theoretic and effective expansion ratios. Wide-spread clinical acceptance for stenting will depend on demonstrating that its safety, efficacy and cost efficiency are superior to those of balloon angioplasty.
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Affiliation(s)
- P W Serruys
- Thoraxcenter, Erasmus University, Rotterdam, The Netherlands
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Metallic Stents. Radiol Clin North Am 1990. [DOI: 10.1016/s0033-8389(22)02661-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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van der Giessen WJ, Serruys PW, van Woerkens LJ, Beatt KJ, Visser WJ, Jongkind JF, van Bremen RH, Ridderhof E, van Loon H, Soei LK. Arterial stenting with self-expandable and balloon-expandable endoprostheses. INTERNATIONAL JOURNAL OF CARDIAC IMAGING 1990; 5:163-71. [PMID: 2230294 DOI: 10.1007/bf01833985] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Coronary angioplasty is complicated by acute occlusion (within 24 hours) and late restenosis (within 6 months) in 2-5% and 20-40% of the cases, respectively. Vascular endoprostheses (stents) may provide the cardiologist with a solution to some of these complications. Several stent-devices are now available for experimental and clinical evaluation. In this study we describe our experience with two metallic stents in normal arteries of swine. Self-expandable, stainless steel stents (3.5 mm diameter) were implanted in 17 peripheral arteries, eight of which were deendothelialized by prior balloon angioplasty. Following implantation, the animals received antithrombotic therapy with acenocoumarol and aspirin (8 stents), or aspirin alone (9 stents). After 1 week repeat angiography was performed, which showed patency of all stented arteries. Microscopy showed complete covering by neointima, 80 microns in thickness. This self-expandable stent (SES) and a balloon-expandable stent (BES), constructed of tantalum, were implanted in normal coronary arteries. SES (3.0 and 3.5 mm) receiving animals were treated with coumadines (10 stents) or received no antithrombotic treatment (16 stents) after implantation. BES receiving animals were also not treated (10 stents). Three untreated animals with SES died suddenly within 48 hours. Postmortem examination showed partial or complete thrombosis of all six stents in these animals, resulting in a patency rate of 62% after 1 week. All animals with SES, which were treated with coumadines, and all animals with BES (untreated) had patent stents after one week. It is concluded that SES implanted in normal coronary arteries of pigs, which do not receive additional antithrombotic treatment, show a 38% occlusion rate within 48 hours, but show 100% patency after 1 week, when the animals are treated with coumadines. BES implanted in normal coronary arteries of pigs, which do not receive antithrombotic drugs, are 100% patent after 1 week.
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Sutton CS, Tominaga R, Harasaki H, Emoto H, Oku T, Kambic HE, Skibinski C, Beck G, Hollman J. Vascular stenting in normal and atherosclerotic rabbits. Studies of the intravascular endoprosthesis of titanium-nickel-alloy. Circulation 1990; 81:667-83. [PMID: 2137049 DOI: 10.1161/01.cir.81.2.667] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Percutaneous transluminal balloon angioplasty would be more effective if the rate of recurrent stenosis were reduced. To evaluate the prevention of restenosis after percutaneous transluminal angioplasty, intravascular endoprosthetic stents of titanium-nickel-alloy were implanted transluminally in seven normal and 21 atherosclerotic rabbits. In normal rabbits, a 3.5-mm diameter stent was implanted in the aorta and a 2.5-mm diameter stent in the right iliac artery, which were followed with serial angiograms from 6 weeks (n = 7) to 8 months (n = 4). There was a mean stenosis of 13.1% in the 2.5-mm and 13.6% in the 3.5-mm stent. There was no significant narrowing compared with the adjacent control segments of artery; histopathology showed a thin, fibrous neointima with smooth muscle cells. Each atherosclerotic rabbit was balloon dilated at two separate stenotic sites; each site was 2.0 cm in length. The aortic site (with 28.8 +/- 13.8% mean stenosis [+/- SD]) was dilated with a 3.5-mm balloon, and the iliac site (with 36.5 +/- 14.2% stenosis) was dilated with a 2.5-mm balloon. In each site, an intravascular stent of corresponding diameter and 7-mm length was implanted in one half of the dilated segment, assigned randomly, and the other half served as the angioplasty control. Angiographically observed restenosis rates and the corresponding histopathology were similar in the atherosclerotic segments that had angioplasty alone versus the atherosclerotic segments that had angioplasty plus stenting. The mean neointimal thickness in the aortas and iliac arteries, respectively, measured 247 +/- 181 microns (+/- SD) and 218 +/- 77 microns after 6 weeks (n = 8) versus 321 +/- 168 and 308 +/- 189 microns after 20 weeks (n = 5, p = NS). At 20 weeks follow-up, there was 29.1 +/- 29.8% (median, 16.4%) stenosis in the aortic stent versus 38.9 +/- 24.1% (median, 34.0%) stenosis in the percutaneous transluminal angioplasty control segment of aorta (n = 5, p = NS) and 81.4 +/- 25.5% stenosis in the iliac artery stent versus 89.3 +/- 15.3% stenosis in the PTA control segment of the right iliac artery (n = 5, p = NS). Comparing stenotic arterial segments treated with angioplasty alone with angioplasty plus intravascular stenting in the atherosclerotic rabbits showed that there was no significant difference in either the histopathologic changes or the restenosis rates.
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Affiliation(s)
- C S Sutton
- Department of Artificial Organs, Biostatistics and Epidemiology, Cleveland Clinic Foundation, Ohio
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Abstract
Coronary angioplasty as it is now performed has several limitations, including abrupt early arterial closure and delayed restenosis. To obviate these problems and to enhance the safety of the technique, several intracoronary stenting devices have been developed and are under investigation. This report reviews the scientific rationale behind stenting, the results of stenting in animal models and the early results in humans. In early clinical investigation, restenosis appears uncommon but abrupt, presumably thrombotic, occlusion has been reported despite aggressive anticoagulation. As long as the potential for this problem remains and the long-term consequences of placing these devices into arteries of great functional importance remain unknown, stent placement must be undertaken with great caution and should be performed under carefully monitored circumstances with meticulous patient follow-up.
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Affiliation(s)
- S G Ellis
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor
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VAN DER GIESSEN W, SERRUYS P, VISSER W, VERDOUW P, VAN SCHALKWIJK W, JONGKIND J. Endothelialization of Intravascular Stents. J Interv Cardiol 1988. [DOI: 10.1111/j.1540-8183.1988.tb00395.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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