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Zeng C, Wu Z, Lei J, Pu H, Qiu P, Peng Z, Liu Y, Ye K, Lu X. Covered Stents vs Bare Metal Stents for Aortoiliac Arterial Diseases: A Systematic Review and Meta-Analysis. J Endovasc Ther 2023:15266028231212761. [PMID: 38031669 DOI: 10.1177/15266028231212761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
PURPOSE Covered stents and bare metal stents (BMS) have been regarded as viable treatment options for aortoiliac arterial diseases. We performed this systematic review and meta-analysis to compare the efficacy of covered stents with BMS for aortoiliac arterial diseases. MATERIALS AND METHODS The Cochrane Library, Embase, and Medline databases were searched by 2 authors (C.Z. and Z.W.) to retrieve all studies comparing the outcomes of covered stents vs BMS for aortoiliac arterial diseases. The Cochrane tool and the Newcastle-Ottawa scale were used to assess the risk of bias in randomized controlled trials and observational studies, respectively. The outcomes at the same stage reported in at least 2 studies were pooled together. The fixed effects model combined the data when I2<50%, otherwise the random effects model was applied. The results for dichotomous variables were presented as odds ratio (OR) or risk difference and 95% confidence interval (CI); continuous variables were reported as mean difference and 95% CI. RESULTS Herein, 10 studies with a total of 1695 limbs were included. The covered stents significantly increased the freedom from target lesion revascularization (OR 2.85, 95% CI: 1.28-6.33, p=0.010) compared to the BMS during a 24-month follow-up. However, no statistically significant difference was found in the technical success, primary patency, secondary patency, major adverse events (MAEs), ankle-brachial index (ABI) improvement, limb salvage, and survival between the two groups. CONCLUSION Compared to BMS, covered stents appear to have similar technical success, primary patency, secondary patency, MAEs, ABI improvement, limb salvage, and survival but may have advantages in reducing target lesion revascularization. More well-designed, prospective studies are warranted to determine such findings. CLINICAL IMPACT Covered stents may increase freedom from target lesion revascularization (TLR) compared to bare metal stents (BMS) in the treatment of aortoiliac arterial diseases. However, technical success, primary patency, secondary patency, major adverse events (MAEs), ABI improvement, limb salvage, and survival were similar. The aforementioned results are still not sufficient to draw a solid conclusion about the selection of stents for aortoiliac arterial diseases. More well-designed, prospective studies are warranted to determine such findings.
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Affiliation(s)
- Chenlin Zeng
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Zhaoyu Wu
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jiahao Lei
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Hongji Pu
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Peng Qiu
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Zhaoxi Peng
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yijun Liu
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Kaichuang Ye
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
- Vascular Center of Shanghai Jiao Tong University, Shanghai, China
| | - Xinwu Lu
- Department of Vascular Surgery, School of Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China
- Vascular Center of Shanghai Jiao Tong University, Shanghai, China
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Lim CS, Black SA. Mechanical characteristics of venous stents to overcome challenges of venous outflow obstruction. INT ANGIOL 2022; 41:240-248. [PMID: 35138073 DOI: 10.23736/s0392-9590.22.04773-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Many challenges posed by the venous outflow obstruction (VOO) are unique to the venous system which require specific mechanical characteristics of stents to overcome them. Therefore, this article aims to review and discuss these challenges and the stent mechanical characteristics required to overcome them. METHODS A literature search was performed with Pubmed with the terms "mechanical characteristics of venous stents" and "mechanical properties of venous stents". RESULTS The venous system poses unique anatomical, physiological and pathological challenges when compared to the arterial counterpart. Several mechanical characteristics specific to venous stents which include the size, inherent forces, and flexibility are important to overcome these unique challenges when treating VOO. The most important stent inherent forces for venous stents include the chronic outward force, radial resistive force, and crush resistance. Various stent materials and designs, particularly laser-cut versus braided-structure stents, and open-cell versus closed-cell stents, determine the mechanical characteristics including the inherent forces of the venous stents. The desired mechanical characteristics of stents needed to overcome the venous system challenges often in conflict or with opposing effects. Therefore, it is important to fine adjust and optimise these characteristics. CONCLUSIONS There are many anatomical, physiological, and pathological challenges unique to the venous system which need to be overcome by the stent system mechanically when treating VOO. Therefore, dedicated venous stents with optimal mechanical characteristics are being developed with different designs and properties to treat VOO. Further research and innovations are needed to improve the stent technology that targets the venous system specifically.
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Affiliation(s)
- Chung S Lim
- Department of Vascular Surgery, Royal Free London NHS Foundation Trust, London, UK - .,Division of Surgery and Interventional Science, Department of Surgical Biotechnology, Faculty of Medical Sciences, University College London, UK -
| | - Stephen A Black
- Academic Department of Vascular Surgery, School of Cardiovascular Medicine and Sciences, King's College London, BHF Centre of Excellence, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
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Serefli D, Saydam O, Engin AY, Atay M. Midterm results of kissing stent reconstruction of the aortoiliac bifurcation. Ann Surg Treat Res 2021; 101:247-255. [PMID: 34692597 PMCID: PMC8506018 DOI: 10.4174/astr.2021.101.4.247] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/19/2021] [Accepted: 08/27/2021] [Indexed: 11/30/2022] Open
Abstract
Purpose One subset of peripheral arterial disease is aortoiliac occlusive diseases (AIOD). AIOD is the term for all arterial lesions between the infrarenal distal aorta and common femoral artery. Implantation of kissing stents (KS) with covered stents (CS), bare-metal stents (BMS) is one of the endovascular treatment (ET) modalities for AIOD involving aortic bifurcation. In this study, we report the outcomes of the KS technique in infrarenal AIOD. Methods Between January 2014 and September 2017, 31 patients who underwent ET were treated with KS technique either with balloon-expandable BMS or balloon-expandable CS. Technical details, clinical success, complications, and patency at follow-up were documented. Results The majority of patients were male (77.4%), and the median age was 62 years (range, 45-78 years). All patients were classified according to the TASC II criteria. Eight patients (25.8%) were classified as TASC B. Fifteen patients (48.4%) were classified as TASC C, and 8 patients (25.8%) were classified as TASC D. These 23 patients were classified as complex AIOD group. BMS was used in 17 patients (54.8%), and CS was used in 14 patients (45.2%). Technical and clinical success was achieved in 100% of treated cases. The median follow-up was 24 months (range, 24-34 months). Primary patency rates at 12, 18, and 24 months after ET were 100%, 96.8%, and 90.3%, respectively. Conclusion We found that the KS technique has satisfying 24-month results, even in complex AIOD lesions, with high technical success and acceptable midterm patency. Key Words: Aorta, Arterial occlusive diseases, Endovascular procedures, Iliac artery, Stents.
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Affiliation(s)
- Deniz Serefli
- Department of Cardiovascular Surgery, Tepecik Training and Research Hospital, Izmir, Turkey
| | - Onur Saydam
- Department of Cardiovascular Surgery, Tepecik Training and Research Hospital, Izmir, Turkey
| | - A Yaprak Engin
- Department of Cardiovascular Surgery, Tepecik Training and Research Hospital, Izmir, Turkey
| | - Mehmet Atay
- Department of Cardiovascular Surgery, Bakirkoy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey
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Lim J, Cho YD, Hong N, Lee J, Yoo DH, Kang HS. Follow-up outcomes of intracranial aneurysms treated using braided or laser-cut stents with closed-cell design: a propensity score-matched case-controlled comparison. J Neurointerv Surg 2020; 13:434-437. [PMID: 32817345 DOI: 10.1136/neurintsurg-2020-016165] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/10/2020] [Accepted: 07/13/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND The impact of various stents on patients with intracranial aneurysms who undergo stent-assisted coiling has been debated. We conducted this study to compare follow-up outcomes of coiling procedures involving braided or laser-cut stents with closed-cell design. A propensity score-matched case-controlled analysis was applied. METHODS A total of 413 intracranial aneurysms consecutively coiled using laser-cut (n=245) or braided stents (n=168) in procedures performed between September 2012 and June 2017 were eligible for study. Time-of-flight magnetic resonance angiography, catheter angiography, or both were used to gauge occlusive status after coiling. Recanalization was determined by Raymond classification (complete occlusion vs recanalization). A propensity score-matched analysis was conducted, based on probability of stent type in use. RESULTS Ultimately, 93 coiled aneurysms (22.5%) showed some recanalization (minor, 51; major, 42) during the follow-up period (mean 21.7±14.5 months). Patient gender (P=0.042), hyperlipidemia (P=0.015), size of aneurysm (P=0.004), neck size (P<0.001), type of aneurysm (P<0.001), and packing density (P=0.024) differed significantly by group. Midterm and cumulative recanalization incidence rates in the braided-stent group were initially lower than those of the laser-cut stent group (P=0.009 and P=0.037, respectively) but they did not differ significantly after 1:1 propensity score matching (midterm OR=0.88, P=0.724; cumulative HR=0.91, P=0.758). CONCLUSION In stent-assisted coiling of intracranial aneurysms, laser-cut and braided stent groups produced similar outcomes in follow-up. Consequently, product selection may hinge on suitability for deployment rather than anticipated results.
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Affiliation(s)
- JeongWook Lim
- Department of Neurosurgery, Chungnam National University Hospital, Chungnam National University College of Medicine, Daejeon, South Korea
| | - Young Dae Cho
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-gu, Seoul, South Korea
| | - Noah Hong
- Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Jeongjun Lee
- Department of Neurosurgery, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, South Korea
| | - Dong Hyun Yoo
- Department of Radiology, Seoul National University Hospital, Seoul National University College of Medicine, Jongno-gu, Seoul, South Korea
| | - Hyun-Seung Kang
- Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea
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Moran CJ. The Collar Sign in Pipeline Embolization Device-Treated Aneurysms. AJNR Am J Neuroradiol 2020; 41:486-487. [PMID: 32139426 DOI: 10.3174/ajnr.a6465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Peivandi AD, Seiler M, Mueller KM, Martens S, Malec E, Asfour B, Lueck S. Elastica degeneration and intimal hyperplasia lead to Contegra® conduit failure. Eur J Cardiothorac Surg 2019; 56:1154-1161. [DOI: 10.1093/ejcts/ezz199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 06/04/2019] [Accepted: 06/09/2019] [Indexed: 02/04/2023] Open
Abstract
Abstract
OBJECTIVES
Currently, Contegra® grafts (processed bovine jugular vein conduits) are widely used for reconstructive surgery of the right ventricular outflow tract in patients with congenital heart disease (CHD). We analysed explanted Contegra conduits from 2 institutions histologically to get a possible hint at the underlying pathomechanisms of degenerative alterations and to find histological correlations of graft failure. Additionally, we compared the explants with a non-implanted processed graft and a native jugular vein obtained from a young bull.
METHODS
The explanted Contegra grafts were gathered during reoperations of 13 patients (male: n = 9, 69.2%; female: n = 4, 30.8%). After standardized histological preparation, samples were stained with dyes haematoxylin and eosin and Elastica van Gieson. Additionally, X-ray pictures revealed the extent of calcification and chelaplex (III)-descaling agent was used to decalcify selected explants.
RESULTS
Processing of the native jugular vein leads to tissue loosening and a loss of elastic fibres. For graft failure after implantation, 2 pathomechanisms were identified: original graft alteration as well as intimal hyperplasia. Elastica degeneration and rearrangement with interfibrillary matrix structures were the main developments observed within the graft itself. Intimal hyperplasia was characterized by fibrous tissue apposition, calcification and heterotopic ossification.
CONCLUSIONS
Regression of the elastic fibre network leads to rigidification of the conduit. In Contegra grafts, atherosclerosis-like changes can be considered the leading cause of graft stenosis and insufficiency. We conclude that both observed mechanisms lead to early reoperation in CHD patients.
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Affiliation(s)
- Armin Darius Peivandi
- Department of Cardiothoracic Surgery, University Hospital Muenster, Muenster, Germany
| | - Martina Seiler
- Department of Cardiothoracic Surgery, University Hospital Muenster, Muenster, Germany
| | - Klaus-Michael Mueller
- Department of Cardiothoracic Surgery, University Hospital Muenster, Muenster, Germany
| | - Sven Martens
- Department of Cardiothoracic Surgery, University Hospital Muenster, Muenster, Germany
| | - Edward Malec
- Department of Cardiothoracic Surgery, University Hospital Muenster, Muenster, Germany
| | - Boulos Asfour
- Department of Pediatric Cardiac and Thoracic Surgery, German Pediatric Heart Center, Sankt Augustin, Sankt Augustin, Germany
| | - Sabrina Lueck
- Department of Cardiothoracic Surgery, University Hospital Muenster, Muenster, Germany
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Stent angioplasty of narrowed right ventricular outflow conduits and pulmonary arteries consistently reduces right ventricular systolic pressures and delays subsequent surgeries. Indian Heart J 2018; 70:879-886. [PMID: 30580860 PMCID: PMC6306346 DOI: 10.1016/j.ihj.2018.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 04/08/2018] [Accepted: 04/23/2018] [Indexed: 11/21/2022] Open
Abstract
Objectives Narrowed right ventricular (RV) outflow conduits and pulmonary arteries (PA) increase RV pressures and warrant interventions. Stent angioplasty is an alternative to more morbid redo-surgery in developing countries. We evaluate the efficacy and safety of stenting and assess need for redo-surgical reinterventions on midterm follow-up after stent angioplasty. Methods Patients who underwent conduit, main PA and bilateral branch PA stenting for elevated RV pressures were analyzed retrospectively. Success was defined as 20% reduction in RV pressures or RV-aortic pressure ratio; 50% reduction in gradients or 50% increase of luminal diameter. Procedural results, complications and need for redo surgeries on follow-up were assessed. Results Among 60 patients aged 1–46 years, 57 were post-operative patients, who needed stenting at a median period of 48 months after surgery. Stenting succeeded in 98% and reduced RV pressures from 105.42 ± 28.39 mmHg to 54.46 ± 16.89 mmHg. Direct major procedural complications in five (8%) patients included procedural failure in one, stent migration in three and lung hemorrhage in one. None of the stented conduits needed a surgical change on a follow-up ranging 3–120 months. Following bilateral PA stenting in twenty-four patients, only two needed a repeat open-heart surgery during follow-up ranging 3–108 months. Catheter reinterventions on follow-up included elective percutaneous pulmonary valve implantation in nine patients and stent redilation in seven patients. Conclusions Stent angioplasty was safe and effective. Surgery was postponed in all stenosed conduits. Elective redilation of stents after bilateral PA stenting may be needed for somatic growth; but open-heart repeat surgeries can be avoided in a majority.
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Borhani S, Hassanajili S, Ahmadi Tafti SH, Rabbani S. Cardiovascular stents: overview, evolution, and next generation. Prog Biomater 2018; 7:175-205. [PMID: 30203125 PMCID: PMC6173682 DOI: 10.1007/s40204-018-0097-y] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/25/2018] [Indexed: 12/01/2022] Open
Abstract
Compared to bare-metal stents (BMSs), drug-eluting stents (DESs) have been regarded as a revolutionary change in coronary artery diseases (CADs). Releasing pharmaceutical agents from the stent surface was a promising progress in the realm of cardiovascular stents. Despite supreme advantages over BMSs, in-stent restenosis (ISR) and long-term safety of DESs are still deemed ongoing concerns over clinically application of DESs. The failure of DESs for long-term clinical use is associated with following factors including permanent polymeric coating materials, metallic stent platforms, non-optimal drug releasing condition, and factors that have recently been supposed as contributory factors such as degradation products of polymers, metal ions due to erosion and degradation of metals and their alloys utilizing in some stents as metal frameworks. Discovering the direct relation between stent materials and associating adverse effects is a complicated process, and yet it has not been resolved. For clinical success it is of significant importance to optimize DES design and explore novel strategies to overcome all problems including inflammatory response, delay endothelialization, and sub-acute stent thrombosis (ST) simultaneously. In this work, scientific reports are reviewed particularly focusing on recent advancements in DES design which covers both potential improvements of existing and recently novel prototype stent fabrications. Covering a wide range of information from the BMSs to recent advancement, this study mostly sheds light on DES's concepts, namely stent composition, drug release mechanism, and coating techniques. This review further reports different forms of DES including fully biodegradable DESs, shape-memory ones, and polymer-free DESs.
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Affiliation(s)
- Setareh Borhani
- Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran
| | - Shadi Hassanajili
- Department of Nanochemical Engineering, School of New Science and Technology, Shiraz University, Shiraz, Iran.
| | - Seyed Hossein Ahmadi Tafti
- Research Center for Advanced Technologies in Cardiovascular Medicine, Tehran Heart Center, Tehran University of Medical Sciences, North Kargar, Tehran, Iran
| | - Shahram Rabbani
- Research Center for Advanced Technologies in Cardiovascular Medicine, Tehran Heart Center, Tehran University of Medical Sciences, North Kargar, Tehran, Iran
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Lee J, Cho YD, Yoo DH, Kang HS, Cho WS, Kim JE, Moon J, Han MH. Does stent type impact coil embolization outcomes in extended follow-up of small-sized aneurysms (< 10 mm)? Neuroradiology 2018; 60:747-756. [DOI: 10.1007/s00234-018-2022-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Accepted: 04/10/2018] [Indexed: 01/20/2023]
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10
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Physical Properties of Venous Stents: An Experimental Comparison. Cardiovasc Intervent Radiol 2018; 41:942-950. [DOI: 10.1007/s00270-018-1916-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 02/21/2018] [Indexed: 10/17/2022]
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Grigioni M, Daniele C, Abbate M, D'Avenio G, Morbiducci U, Del Gaudio C, Barbaro V. Endovascular Stents: Market Vigilance and Risk Factors. Int J Artif Organs 2018; 27:45-54. [PMID: 14984183 DOI: 10.1177/039139880402700110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
With the aim of enhancing the safety and reliability level of coronary stents, we analyzed data collected from accident reports drawn from the MAUDE database (Manufacturer and User Facility Device Experience Database) of the FDA from 1996 to 2000. This analysis allowed us to highlight problems related to the use of coronary stents by means of the analysis of these reports at different levels, beginning from the causes that can lead to a certain type of accident up to the possible complication related to that event. Moreover we analyzed the procedure outcomes in terms of stent position inside the patient's body and the possible therapies adopted to solve the problems. The results showed that the most probable event that can lead to an accident is the stent separation from the balloon which, alone, turns up in a number of cases equal to the sum of all the others. This result highlights the importance of the technical skill of the operators accomplished by special training and of the importance of clarity and completeness in the instructions for the use of the device. Another critical point is the reliability of the device which must guarantee an adequate safety level when it is used according to the instructions.
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Affiliation(s)
- M Grigioni
- Laboratory of Biomedical Engineering, Istituto Superiore di Sanità, Roma, Italy.
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Affiliation(s)
- Julio C. Palmaz
- The University of Texas Health Science Center, San Antonio, TX, USA
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13
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An intraluminal stent facilitates light-activated vascular anastomosis. J Trauma Acute Care Surg 2017; 83:S43-S49. [DOI: 10.1097/ta.0000000000001487] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Abstract
According to the 2007 TransAtlantic Inter-Society Consensus (TASC II) guidelines, surgery is the preferred treatment for extensive (TASC II type C and D) aortoiliac occlusive disease (AIOD). Recent studies, however, have shown that endovascular management can be an effective first-line treatment option for TASC II type C and D categories. While endovascular therapy is now commonly performed in patients with TASC II type D lesions, very few studies have investigated the feasibility and effectiveness of extending endovascular therapy to the most severe subcategory of TASC II D lesions, chronic infrarenal aortoiliac occlusion (CIAO). Herein, we present our technique for endovascular treatment of CIAO which relies on bidirectional subintimal aortoiliac dissection, wire snare for true lumen reentry, and combined balloon-expandable and self-expanding covered stent reconstruction of the aortic bifurcation and bilateral iliac arteries. This technique safely extends the reach of endovascular therapy to the most severe subcategory of TASC II D AIOD, CIAO. It is a viable minimally invasive alternative to aortobifemoral bypass surgery. Long-term follow-up of larger cohorts is needed to verify clinical efficacy and durability of therapy.
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Greaves NS, Katsogridakis E, Faris B, Murray D. Prophylactic antibiotics for percutaneous endovascular procedures. Eur J Clin Microbiol Infect Dis 2016; 36:597-601. [DOI: 10.1007/s10096-016-2848-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/15/2016] [Indexed: 10/20/2022]
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16
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Wang C, Tian Z, Liu J, Jing L, Paliwal N, Wang S, Zhang Y, Xiang J, Siddiqui AH, Meng H, Yang X. Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device. J Transl Med 2016; 14:199. [PMID: 27370946 PMCID: PMC4930570 DOI: 10.1186/s12967-016-0959-9] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 06/23/2016] [Indexed: 11/14/2022] Open
Abstract
Background The aim of this study was to quantify the effect of the new Low-profile Visualized Intraluminal Support (LVIS®D) device and the difference of fluid diverting effect compared with the Pipeline device and the Enterprise stent using computational fluid dynamics (CFD). Methods In this research, we simulated three aneurysms constructed from 3D digital subtraction angiography (DSA). The Enterprise, LVIS and the Pipeline device were virtually conformed to fit into the vessel lumen and placed across the aneurysm orifice. Computational fluid dynamics analysis was performed to compare the hemodynamic differences such as WSS, Velocity and Pressure among these stents. Results Control referred to the unstented model, the percentage of hemodynamic changes were all compared to Control. A single LVIS stent caused more wall shear stress reduction than double Enterprise stents (39.96 vs. 30.51 %) and velocity (23.13 vs. 18.64 %). Significant reduction in wall shear stress (63.88 %) and velocity (46.05 %) was observed in the double-LVIS stents. A single Pipeline showed less reduction in WSS (51.08 %) and velocity (37.87 %) compared with double-LVIS stent. The double-Pipeline stents resulted in the most reduction in WSS (72.37 %) and velocity (54.26 %). Moreover, the pressure increased with minuscule extent after stenting, compared with the unstented model. Conclusions This is the first study analyzing flow modifications associated with LVIS stents. We found that the LVIS stent has certain hemodynamic effects on cerebral aneurysms: a single LVIS stent caused more flow reductions than the double-Enterprise stent but less than a Pipeline device. Nevertheless, the double-LVIS stent resulted in a better flow diverting effect than a Pipeline device.
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Affiliation(s)
- Chao Wang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China.,Department of Neurosurgery, The Affiliated Hospital, Binzhou Medical University, Binzhou, Shandong, China
| | - Zhongbin Tian
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Jian Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Linkai Jing
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Nikhil Paliwal
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Shengzhang Wang
- Department of Mechanics and Engineering Science, Fudan University, Shanghai, China
| | - Ying Zhang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China
| | - Jianping Xiang
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Adnan H Siddiqui
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Neurosurgery, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Hui Meng
- Toshiba Stroke and Vascular Research Center, University at Buffalo, The State University of New York, Buffalo, NY, USA.,Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Xinjian Yang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tian Tan Hospital, Capital Medical University, TiantanXili 6, Dongcheng District, Beijing, China.
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Fontaine AB, Koelling K, Passos SD, Cearlock J, Hoffman R, Spigos DG. Polymeric Surface Modifications of Tantalum Stents. J Endovasc Ther 2016; 3:276-83. [PMID: 8800230 DOI: 10.1177/152660289600300306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Purpose: To compare two kinds of polymer-coated tantalum stents with bare tantalum stents (control) to determine if the coatings can improve thromboresistance. Methods: Twenty-seven Fontaine-Dake stents were balloon expanded in three 8-mm × 80-cm.polytetrafluoroethylene (PTFE) grafts; 9 stents were bare tantalum (T); 9 were coated with polyetherurethane (PL); and 9 were coated with parylene (PA). There were 9 stents placed in each graft as follows: 3 tantalum, 3 polyetherurethane, and 3 parylene. In swine whose platelets had been radiolabeled with indium 111, the ends of each stented graft were connected to 14F femoral and venous sheaths to create an ex vivo fistula. Each graft was exposed to blood for 30, 60, and 120 minutes. At the end of each test period, the stented grafts were disconnected from the sheaths, flushed with saline until clear, and then flushed with formalin. The stents were removed from the grafts, and a radionuclide well counter recorded radionuclide counts from each stent type at each period of blood contact. These values were converted to platelet density per 1000 mUm2. Stents were then photographed and scanned with electron microscopy (EM) for qualitative analysis. Possible significant differences in platelet adhesion with the three types of stents (both between stent groups and within stent groups) were examined using a two-tailed Student's f-test. Results: There were significantly fewer platelets adsorbed on PA versus T at all time periods (p < 0.005); on PL versus T at 60 and 120 minutes (p < 0.005); and on PA versus PL at 30 and 120 minutes (p < 0.0005). There was no significant difference in platelet density within each stent group (p = 0.1). Mean platelet density (number of platelets per 1000 mUm2 ± SD) was as follows: at 30 minutes: T = 1891 ± 965; PL = 373 ± 193; and PA = 27 ± 3; at 60 minutes: T = 6226 ± 1621; PL = 1573 ± 793; and PA = 1185 ± 710; at 120 minutes: T = 5307 ± 591; PL = 3164 ± 318; and PA = 180 ± 100. Gross inspection of the 120-minute groups demonstrated focal areas of thrombus on T, less on PL, and none on PA. Scanning EM demonstrated extensive platelet accumulation covering T at all time periods, less on PL, and even less on PA. Conclusions: Polymeric surface modification of tantalum stents with parylene and/or polyetherurethane can improve the acute thromboresistance of these devices; parylene appears to be the more thromboresistant of the two coatings.
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Affiliation(s)
- A B Fontaine
- Division of Vascular and Interventional Radiology, Ohio State University Hospitals, Columbus, USA
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Dosluoglu HH, Curl GR, Doerr RJ, Painton F, Shenoy S. Stent-Related Iliac Artery and Iliac Vein Infections: Two Unreported Presentations and Review of the Literature. J Endovasc Ther 2016; 8:202-9. [PMID: 11357983 DOI: 10.1177/152660280100800217] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose: To discuss the presentation, diagnosis, and treatment of stent-related infections on the basis of 2 new cases and historical review. Case Reports: Two previously unreported cases of vascular stent infection are presented with a summary of cases from the literature. One case involved an iliac artery stent infection secondary to a remote bacteremia 6 months after stent placement. The other case was an early iliac vein stent infection, a previously unreported site of this complication. Both cases were diagnosed by use of computed tomography and were treated surgically after medical management failed. Both patients survived. Conclusions: A high index of suspicion is necessary for the diagnosis of stent infections, and an aggressive treatment is usually necessary for survival. Prophylactic antibiotics should definitely be considered in cases involving repeat interventions and prolonged catheterization, as well as before bacteremia-inducing therapies.
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Affiliation(s)
- H H Dosluoglu
- Division of Vascular Surgery, State University of New York at Buffalo, USA
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Ma J, Thompson M, Zhao N, Zhu D. Similarities and differences in coatings for magnesium-based stents and orthopaedic implants. J Orthop Translat 2014; 2:118-130. [PMID: 27695671 PMCID: PMC5044877 DOI: 10.1016/j.jot.2014.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Magnesium (Mg)-based biodegradable materials are promising candidates for the new generation of implantable medical devices, particularly cardiovascular stents and orthopaedic implants. Mg-based cardiovascular stents represent the most innovative stent technology to date. However, these products still do not fully meet clinical requirements with regards to fast degradation rates, late restenosis, and thrombosis. Thus various surface coatings have been introduced to protect Mg-based stents from rapid corrosion and to improve biocompatibility. Similarly, different coatings have been used for orthopaedic implants, e.g., plates and pins for bone fracture fixation or as an interference screw for tendon-bone or ligament-bone insertion, to improve biocompatibility and corrosion resistance. Metal coatings, nanoporous inorganic coatings and permanent polymers have been proved to enhance corrosion resistance; however, inflammation and foreign body reactions have also been reported. By contrast, biodegradable polymers are more biocompatible in general and are favoured over permanent materials. Drugs are also loaded with biodegradable polymers to improve their performance. The key similarities and differences in coatings for Mg-based stents and orthopaedic implants are summarized.
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Affiliation(s)
- Jun Ma
- Department of Chemical, Biological and Bio-Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC, USA; National Science Foundation (NSF) Engineering Research Center-Revolutionizing Metallic Biomaterials, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
| | - Marc Thompson
- Department of Chemical, Biological and Bio-Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC, USA; National Science Foundation (NSF) Engineering Research Center-Revolutionizing Metallic Biomaterials, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
| | - Nan Zhao
- Department of Chemical, Biological and Bio-Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC, USA; National Science Foundation (NSF) Engineering Research Center-Revolutionizing Metallic Biomaterials, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
| | - Donghui Zhu
- Department of Chemical, Biological and Bio-Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC, USA; National Science Foundation (NSF) Engineering Research Center-Revolutionizing Metallic Biomaterials, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
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20
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Teplitzky BA, Connolly AT, Bajwa JA, Johnson MD. Computational modeling of an endovascular approach to deep brain stimulation. J Neural Eng 2014; 11:026011. [PMID: 24608363 DOI: 10.1088/1741-2560/11/2/026011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
OBJECTIVE Deep brain stimulation (DBS) therapy currently relies on a transcranial neurosurgical technique to implant one or more electrode leads into the brain parenchyma. In this study, we used computational modeling to investigate the feasibility of using an endovascular approach to target DBS therapy. APPROACH Image-based anatomical reconstructions of the human brain and vasculature were used to identify 17 established and hypothesized anatomical targets of DBS, of which five were found adjacent to a vein or artery with intraluminal diameter ≥1 mm. Two of these targets, the fornix and subgenual cingulate white matter (SgCwm) tracts, were further investigated using a computational modeling framework that combined segmented volumes of the vascularized brain, finite element models of the tissue voltage during DBS, and multi-compartment axon models to predict the direct electrophysiological effects of endovascular DBS. MAIN RESULTS The models showed that: (1) a ring-electrode conforming to the vessel wall was more efficient at neural activation than a guidewire design, (2) increasing the length of a ring-electrode had minimal effect on neural activation thresholds, (3) large variability in neural activation occurred with suboptimal placement of a ring-electrode along the targeted vessel, and (4) activation thresholds for the fornix and SgCwm tracts were comparable for endovascular and stereotactic DBS, though endovascular DBS was able to produce significantly larger contralateral activation for a unilateral implantation. SIGNIFICANCE Together, these results suggest that endovascular DBS can serve as a complementary approach to stereotactic DBS in select cases.
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Affiliation(s)
- Benjamin A Teplitzky
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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21
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Lee CJ, Srinivas K, Qian Y. Three-dimensional hemodynamic design optimization of stents for cerebral aneurysms. Proc Inst Mech Eng H 2014; 228:213-24. [DOI: 10.1177/0954411914523405] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flow-diverting stents occlude aneurysms by diverting the blood flow from entering the aneurysm sac. Their effectiveness is determined by the thrombus formation rate, which depends greatly on stent design. The aim of this study was to provide a general framework for efficient stent design using design optimization methods, with a focus on stent hemodynamics as the starting point. Kriging method was used for completing design optimization. Three different cases of idealized stents were considered, and 40–60 samples from each case were evaluated using computational fluid dynamics. Using maximum velocity and vorticity reduction as objective functions, the optimized designs were identified from the samples. A number of optimized stent designs have been found from optimization, which revealed that a combination of high pore density and thin struts is desired. Additionally, distributing struts near the proximal end of aneurysm neck was found to be effective. The success of the methods and framework devised in this study offers a future possibility of incorporating other disciplines to carry out multidisciplinary design optimization.
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Affiliation(s)
- Chang-Joon Lee
- The Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
| | - Karkenahalli Srinivas
- The Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
| | - Yi Qian
- The Australian School of Advanced Medicine, Macquarie University, Sydney, NSW, Australia
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22
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Kohn J, Zeltinger J. Degradable, drug-eluting stents: a new frontier for the treatment of coronary artery disease. Expert Rev Med Devices 2014; 2:667-71. [PMID: 16293093 DOI: 10.1586/17434440.2.6.667] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This article reviews the clinical use of stents in the treatment of coronary artery disease and the rationale for the use of degradable, drug-eluting polymer stents. The authors note the challenges of using off-the-shelf polymers for the development of degradable stents, as well as the interplay between polymer properties and a functional stent design. Drug-eluting metal stents are the most significant advancement in the treatment of coronary artery disease, and have significantly reduced the occurrence of in-stent restenosis after placement. Some regard drug-eluting metal stents as the final technologic advancement in the treatment of coronary artery disease, others consider the future development of degradable, drug-eluting stents as the next logical step.
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Affiliation(s)
- Joachim Kohn
- New Jersey Center for Biomaterials, Rutgers University, 145 Bevier Road, Piscataway, NJ 08854, USA.
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23
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Lim JI, Kim SI, Jung Y, Kim SH. Fabrication and Medical Applications of Lotus-leaf-like Structured Superhydrophobic Surfaces. POLYMER-KOREA 2013. [DOI: 10.7317/pk.2013.37.4.411] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
In patients with critical limb ischemia, the first-line approach for limb salvage has shifted over the past decade from bypass surgery to endovascular intervention. Stenting for the treatment of lower-extremity arterial occlusive disease is an important tool and continues to evolve, with new stent designs and technologies that have been developed to provide superior patency rates and limb salvage. In this article, we discuss the role of peripheral stenting in the treatment of patients with critical limb ischemia, including a review of the relevant current literature and the future directions of such interventions.
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Affiliation(s)
- Hosam F El-Sayed
- Methodist DeBakey Heart & Vascular Center, The Methodist Hospital, Houston, Texas, USA
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25
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Lim JI, Kim SI, Kim SH. Lotus-leaf-like structured heparin-conjugated poly(L-lactide-co-epsilon-caprolactone) as a blood compatible material. Colloids Surf B Biointerfaces 2012; 103:463-7. [PMID: 23261567 DOI: 10.1016/j.colsurfb.2012.11.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 11/07/2012] [Accepted: 11/13/2012] [Indexed: 11/24/2022]
Abstract
A heparin-conjugated biodegradable polymer was synthesized by direct coupling of heparin to poly(L-lactide-co-ɛ-caprolactone) (PLCL) and was manufactured into lotus-leaf-like structured films. We evaluated whether lotus-leaf-like structured heparin-conjugated PLCL (LH-PLCL) could be applied to blood vessel tissue engineering. Differences in the surface structures of the films with respect to hydrophobicity and the lotus effect as well as the antithrombotic efficiency in human whole blood were examined using scanning electron microscopy (SEM) and a contact angle meter. Recovery testing was conducted using a tensile strength testing machine, and quantitative analysis of conjugated heparin was performed using the toluidine blue colorimetric method. The concentration of conjugated heparin was 0.14 μg/mg H-PLCL, and the contact angle with the lotus-leaf-like surface was approximately 120°. Furthermore, the LH-PLCL film yielded a lower platelet adhesion rate (around less than 1.4%) in whole blood than that yielded by an untreated PLCL film. These results indicate a unique property of bound heparin and the lotus-leaf-like structure. This novel LH-PLCL polymer could be applied as a blood/tissue compatible biodegradable material for implantable medical devices and tissue engineering.
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Affiliation(s)
- Jin Ik Lim
- Division of Life and Health Sciences, Biomaterials Research Center, Korea Institute of Science and Technology, Seoul, Republic of Korea
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26
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Waterhouse A, Wise SG, Yin Y, Wu B, James B, Zreiqat H, McKenzie DR, Bao S, Weiss AS, Ng MK, Bilek MM. In vivo biocompatibility of a plasma-activated, coronary stent coating. Biomaterials 2012; 33:7984-92. [DOI: 10.1016/j.biomaterials.2012.07.059] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 07/28/2012] [Indexed: 01/02/2023]
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27
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Aktas C, Dörrschuck E, Schuh C, Miró MM, Lee J, Pütz N, Wennemuth G, Metzger W, Oberringer M, Veith M, Abdul-Khaliq H. Micro- and nanostructured Al2O3 surfaces for controlled vascular endothelial and smooth muscle cell adhesion and proliferation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2012. [DOI: 10.1016/j.msec.2012.02.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Seshadhri S, Janiga G, Beuing O, Skalej M, Thévenin D. Impact of stents and flow diverters on hemodynamics in idealized aneurysm models. J Biomech Eng 2011; 133:071005. [PMID: 21823744 DOI: 10.1115/1.4004410] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cerebral aneurysms constitute a major medical challenge as treatment options are limited and often associated with high risks. Statistically, up to 3% of patients with a brain aneurysm may suffer from bleeding for each year of life. Eight percent of all strokes are caused by ruptured aneurysms. In order to prevent this rupture, endovascular stenting using so called flow diverters is increasingly being regarded as an alternative to the established coil occlusion method in minimally invasive treatment. Covering the neck of an aneurysm with a flow diverter has the potential to alter the hemodynamics in such a way as to induce thrombosis within the aneurysm sac, stopping its further growth, preventing its rupture and possibly leading to complete resorption. In the present study the influence of different flow diverters is quantified considering idealized patient configurations, with a spherical sidewall aneurysm placed on either a straight or a curved parent vessel. All important hemodynamic parameters (exchange flow rate, velocity, and wall shear stress) are determined in a quantitative and accurate manner using computational fluid dynamics when varying the key geometrical properties of the aneurysm. All simulations are carried out using an incompressible, Newtonian fluid with steady conditions. As a whole, 72 different cases have been considered in this systematic study. In this manner, it becomes possible to compare the efficiency of different stents and flow diverters as a function of wire density and thickness. The results show that the intra-aneurysmal flow velocity, wall shear stress, mean velocity, and vortex topology can be considerably modified thanks to insertion of a suitable implant. Intra-aneurysmal residence time is found to increase rapidly with decreasing stent porosity. Of the three different implants considered in this study, the one with the highest wire density shows the highest increase of intra-aneurysmal residence time for both the straight and the curved parent vessels. The best hemodynamic modifications are always obtained for a small aneurysm diameter.
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Affiliation(s)
- Santhosh Seshadhri
- Laboratory of Fluid Dynamics and Technical Flows, University of Magdeburg Otto von Guericke, Universitätsplatz 2, D-39106 Magdeburg, Germany.
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Zhao T, Li Y, Gao Y, Xiang Y, Chen H, Zhang T. Hemocompatibility investigation of the NiTi alloy implanted with tantalum. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2011; 22:2311-2318. [PMID: 21833606 DOI: 10.1007/s10856-011-4406-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 07/28/2011] [Indexed: 05/31/2023]
Abstract
A composite TiO(2)/Ta(2)O(5) nano-film has been formed on the NiTi shape memory alloy by Ta implantation. The wettability, protein adsorption, platelets adhesion and hemolysis tests are conducted to evaluate the hemocompatibility. The contact angle measurements showed that the surface of the NiTi alloy kept hydrophilic before and after Ta implantation, although the water contact angle increased with the increasing of implantation current. Both of the surface energy and the interfacial tension decreased after Ta implantation. The protein adsorption behavior was investigated by (125)I isotope labeling. The fibrinogen adsorption was enhanced by a high surface roughness or a large interfacial tension, while the albumin adsorption was insensitive to the surface modification. Platelet adhesion and activation were weakened and the hemolysis rate was reduced at least 46% after Ta implantation due to the decreased surface energy and improved corrosion resistance ability, respectively.
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Affiliation(s)
- Tingting Zhao
- School of Materials Science and Engineering, Beihang University, #37, Xueyuan Road, Beijing, 100191, People's Republic of China
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30
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Mwipatayi BP, Thomas S, Wong J, Temple SEL, Vijayan V, Jackson M, Burrows SA. A comparison of covered vs bare expandable stents for the treatment of aortoiliac occlusive disease. J Vasc Surg 2011; 54:1561-70. [PMID: 21906903 DOI: 10.1016/j.jvs.2011.06.097] [Citation(s) in RCA: 169] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 06/28/2011] [Accepted: 06/28/2011] [Indexed: 10/17/2022]
Abstract
OBJECTIVE This trial was conducted to determine if covered stents offer a patency advantage over bare-metal stents in the treatment of aortoiliac arterial occlusive disease. METHODS The Covered Versus Balloon Expandable Stent Trial (COBEST), a prospective, multicenter, randomized controlled trial, was performed involving 168 iliac arteries in 125 patients with severe aortoiliac occlusive disease who were randomly assigned to receive a covered balloon-expandable stent or bare-metal stent. Patient demographic data, clinical signs and symptoms, TransAtlantic Inter-Society Consensus (TASC) classification, and preprocedure and postprocedure ankle-brachial index measurements were recorded. The primary end points included freedom from binary restenosis and stent occlusion of the treated area, as determined by ultrasound imaging or quantitative visual angiography, or both. Postprocedural follow-up was at 1, 6, 12, and 18 months. RESULTS Aortoiliac lesions treated with a covered stent were significantly more likely to remain free from binary restenosis than those that were treated with a bare-metal stent (hazard ratio [HR], 0.35; 95% confidence interval (CI), 0.15-0.82; P = .02). Freedom from occlusion was also higher in lesions treated with covered stents than in those treated with a bare-metal stent (HR, 0.28; 95% CI, 0.07-1.09); however, this did not reach statistical significance (P = .07). Subgroup analyses demonstrated a significant difference in freedom from binary restenosis for covered stents in TASC C and D lesions compared with a bare stent (HR, 0.136; 95% CI, 0.042-0.442). This difference was not demonstrated for TASC B lesions (HR, 0.748; 95% CI, 0.235-2.386). CONCLUSIONS COBEST demonstrates covered and bare-metal stents produce similar and acceptable results for TASC B lesions. However, covered stents perform better for TASC C and D lesions than bare stents in longer-term patency and clinical outcome.
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Affiliation(s)
- Bibombe P Mwipatayi
- Department of Vascular Surgery, Royal Perth Hospital, Perth, Western Australia, Australia.
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Placement of endovascular stent across the branching arteries: long-term serial evaluation of stent-tissue responses overlying the arterial orifices in an experimental study. Cardiovasc Intervent Radiol 2011; 35:1154-62. [PMID: 21826575 DOI: 10.1007/s00270-011-0243-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 07/22/2011] [Indexed: 10/17/2022]
Abstract
PURPOSE This study was designed to investigate the effects of stenting across the branching arteries on the patency and stent-tissue responses over the branching arterial orifices. METHODS Thirteen dogs were observed after placing aortic stents across the celiac arteries (CA), superior mesenteric arteries (SMA), and renal arteries (RA). The animals were grouped according to stent types: large-cell group (n = 6) and small-cell group (n = 7). Angiography was performed to evaluate the branching artery patency at 2, 6, and 12 months after stent insertion, and the stent-tissue responses covering the orifices were evaluated on histopathologic examination. RESULTS All branching arteries were patent on follow-up angiography; however, three patterns of stent-tissue responses over the orifices were observed: neointimal layering, bridging septa, and papillary hyperplasia. Although neointimal layering and bridging septa were evenly observed, severe papillary hyperplasia was more frequent at SMA and CA than RA. Four RA showed less than 50% ostial patency, and localized infarct was observed in six kidneys (24%). The ostial patency tended to decrease with small-cell stent during the follow-up period. CONCLUSIONS Various stent-tissue responses over the branching artery orifices are induced by the aortic stent covering the branching arteries and may not be easily detected by conventional angiography. Subclinical renal infarct also may occur despite patent renal angiography.
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Abstract
Abstract . Topography plays a major role on surface-cell interaction beside the surface chemistry. We investigated the effect of the nanotopography on vascular cell adhesion and proliferation in order to improve endothelialisation for restenosis treatment. In this context, Al2O3 nanowires (NWs) composed of a stable Al2O3 shell and an Al core were synthesized by chemical vapour deposition (CVD) of the molecular precursor (tBuOAlH2)2. After the detailed material characterization, human umbilical vein endothelial cells (HUVEC) and human umbilical vein smooth muscle cells (HUVSMC) were seeded and cultivated on these surfaces. Our preliminary results showed that there is a preference of HUVEC adhesion on NWs in comparison to that of HUVSMC. The control of the cell–surface interaction by the topography may represent a key issue for the future stent material design.
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Waterhouse A, Wise SG, Ng MKC, Weiss AS. Elastin as a nonthrombogenic biomaterial. TISSUE ENGINEERING PART B-REVIEWS 2011; 17:93-9. [PMID: 21166482 DOI: 10.1089/ten.teb.2010.0432] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Surface-induced thrombosis is a significant issue for artificial blood-contacting materials used in the treatment of cardiovascular diseases. The development of biomaterials and tissue-engineered constructs that mimic the vasculature represents a way to overcome this problem. Elastin is an extracellular matrix macromolecule that imparts arterial elasticity where it comprises up to 50% of the nonhydrated mass of the vessel. In addition to its critical role in maintaining vessel integrity and elastic properties under pulsatile flow, elastin plays an important role in signaling and regulating luminal endothelial cells and smooth muscle cells in the arterial wall. Despite its well-established significance in the vasculature and its growing use as a biomaterial in tissue engineering, the hemocompatibility of elastin is often overlooked. Past studies pointing to the potential of arterial elastin and decellularized elastin as nonthrombogenic materials have begun to be realized, with elastin scaffolds and coatings displaying increased hemocomptibility. This review explores the mechanisms of elastin's nonthrombogenicity and highlights the current problems limiting its wider application as a biomaterial. We discuss the benefits of constructing biomaterials encompassing the relevant mechanical and biological features of elastin to provide enhanced hemocompatibility to biomaterials.
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Affiliation(s)
- Anna Waterhouse
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
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34
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Gu L, Zhao S, Muttyam AK, Hammel JM. The Relation Between the Arterial Stress and Restenosis Rate After Coronary Stenting. J Med Device 2010. [DOI: 10.1115/1.4002238] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Two commercially available stents (the Palmaz–Schatz (PS) and S670 stents) with reported high and low restenosis rates, respectively, have been investigated in this paper. Finite element models simulating the stent, plaque, and artery interactions in 3 mm stenosed right coronary arteries were developed. These models were used to determine the stress field in artery walls after stent implantation. The material properties of porcine arteries were measured and implemented in the numerical models. The stress concentration induced in the artery by the PS stent was found to be more than double that of the S670 stent. It demonstrated a good correlation with the reported restenosis rate. The effects of stent structures, compliance mismatch, plaque geometry, and level of stenosis were studied. Results suggested that stent designs and tissue properties cause alterations in vascular anatomy that adversely affect arterial stress distributions within the wall, which impact vessel responses such as restenosis. Appropriate modeling of stent, plaque, and artery interactions provided insights for evaluating alterations to the arterial mechanical environment, as well as biomechanical factors leading to restenosis.
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Affiliation(s)
- Linxia Gu
- Department of Mechanical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656
| | - Shijia Zhao
- Department of Mechanical Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656
| | | | - James M. Hammel
- Department of Surgery, University of Nebraska Medical Center, Omaha, NE 68114
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Waterhouse A, Yin Y, Wise SG, Bax DV, McKenzie DR, Bilek MMM, Weiss AS, Ng MKC. The immobilization of recombinant human tropoelastin on metals using a plasma-activated coating to improve the biocompatibility of coronary stents. Biomaterials 2010; 31:8332-40. [PMID: 20708259 DOI: 10.1016/j.biomaterials.2010.07.062] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Accepted: 07/15/2010] [Indexed: 10/19/2022]
Abstract
Current endovascular stents have sub-optimal biocompatibility reducing their clinical efficacy. We previously demonstrated a plasma-activated coating (PAC) that covalently bound recombinant human tropoelastin (TE), a major regulator of vascular cells in vivo, to enhance endothelial cell interactions. We sought to develop this coating to enhance its mechanical properties and hemocompatibility for application onto coronary stents. The plasma vapor composition was altered by incorporating argon, nitrogen, hydrogen or oxygen to modulate coating properties. Coatings were characterized for 1) surface properties, 2) mechanical durability, 3) covalent protein binding, 4) endothelial cell interactions and 5) thrombogenicity. The N(2)/Ar PAC had optimal mechanical properties and did not delaminate after stent expansion. The N(2)/Ar PAC was mildly hydrophilic and covalently bound the highest proportion of TE, which enhanced endothelial cell proliferation. Acute thrombogenicity was assessed in a modified Chandler loop using human blood. Strikingly, the N(2)/Ar PAC alone reduced thrombus weight by ten-fold compared to 316L SS, a finding unaltered with immobilized TE. Serum soluble P-selectin was reduced on N(2)/Ar PAC and N(2)/Ar PAC + TE (p < 0.05), consistent with reduced platelet activation. We have demonstrated a coating for metal alloys with multifaceted biocompatibility that resists delamination and is non-thrombogenic, with implications for improving coronary stent efficacy.
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Affiliation(s)
- Anna Waterhouse
- School of Molecular Bioscience, University of Sydney, NSW 2006, Australia
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36
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Li J, Lan ZG, Xie XD, You C, He M. Traumatic Carotid-Cavernous Fistulas Treated with Covered Stents: Experience of 12 Cases. World Neurosurg 2010; 73:514-9. [PMID: 20920935 DOI: 10.1016/j.wneu.2010.02.062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Accepted: 02/20/2010] [Indexed: 10/19/2022]
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Choi MY, Oh HJ, Kwon KJ, Song EM, Kim SH, Jun YH, Choi HJ, Kim YK. A Case Report on Successful Nonsurgical Treatment Using Antibiotics Alone in Aortic Stent Infection Diagnosed by Positron Emission Tomography. Infect Chemother 2010. [DOI: 10.3947/ic.2010.42.6.407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Min Young Choi
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Hyun Jung Oh
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Kyoung Joo Kwon
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Eun Mi Song
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Soo Hyun Kim
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Yun Hee Jun
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Hee Jung Choi
- Department of Internal Medicine, Ewha Womans University, College of Medicine, Seoul, Korea
| | - Yoo Kyoung Kim
- Department of Radiology, Ewha Womans University, College of Medicine, Seoul, Korea
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Choubey A, Marton D, Sprague EA. Human aortic endothelial cell response to 316L stainless steel material microstructure. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2009; 20:2105-2116. [PMID: 19466532 DOI: 10.1007/s10856-009-3780-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Accepted: 05/07/2009] [Indexed: 05/27/2023]
Abstract
The role of metal microstructure (e.g. grain sizes) in modulating cell adherence behavior is not well understood. This study investigates the effect of varying grain sizes of 316L stainless steel (SS) on the attachment and spreading of human aortic endothelial cells (HAECs). Four different grain size samples; from 16 to 66 microm (ASTM 9.0-4.9) were sectioned from sheets. Grain structure was revealed by polishing and etching with glycergia. Contact angle measurement was done to assess the hydrophilicity of the specimens. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the roughness and surface chemistry of the specimens. Cells were seeded on mechanically polished and chemically etched specimens followed by identification of activated focal adhesion sites using fluorescently tagged anti-pFAK (phosphorylated focal adhesion kinase). The 16 microm grain size etched specimens had significantly (P < 0.01) higher number of cells attached per cm(2) than other specimens, which may be attributed to the greater grain boundary area and associated higher surface free energy. This study shows that the underlying material microstructure may influence the HAEC behavior and may have important implications in endothelialization.
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Affiliation(s)
- Animesh Choubey
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249-1644, USA.
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Moreira SM, Kambara AM, Ajzen S, Costa Junior JDR. Quantificação volumétrica da hiperplasia neointimal em artérias ilíacas após implante de suporte intravascular metálico. Radiol Bras 2009. [DOI: 10.1590/s0100-39842009000400008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Quantificar a hiperplasia neointimal em artérias ilíacas após stent, correlacionando fatores clínicos, arteriais e materiais dos stents. MATERIAIS E MÉTODOS: De junho de 2003 a agosto de 2005, 60 pacientes realizaram angioplastia transluminal percutânea e stent. Desses, 30 foram reestudados com ultrassonografia intravascular. Os dados foram analisados no laboratório de análise quantitativa. RESULTA-DOS: Dezesseis pacientes eram do sexo masculino (53,3%) e 14 (46,7%), do sexo feminino. A média de idade foi de 60,3 anos. Apresentaram hipertensão arterial 22 pacientes (73,3%), tabagismo, 18 (62,1%), hiperlipidemia, 20 (66,7%), e diabetes, 9 (30%). Foram implantados 20 stents de nitinol (66,7%) e 10 de aço inoxidável (33,3%). Quatro pacientes eram TASC A (13,3%), 15 eram TASC B (50%) e 11, TASC C (36,7%). O volume da hiperplasia variou de 49,02 mm³ a 112,87 mm³ (média de 80,33 mm³). O percentual de obstrução intra-stent variou de 18% a 47% (média de 27,4%). Os resultados clínicos obtidos com stent se mantiveram até o reestudo. CONCLUSÃO: A hiperplasia neointimal sempre ocorre após a angioplastia transluminal percutânea e stent, porém os percentuais de obstrução não foram superiores a 50% em nenhum caso. Não houve diferença estatisticamente significante dos percentuais de obstrução intra-stent quanto aos materiais dos stents, aos fatores clínicos e aos fatores arteriais.
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Affiliation(s)
| | | | - Sergio Ajzen
- Universidade Federal de São Paulo/Escola Paulista de Medicina, Brasil
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Seiji K, Tsuda M, Matsuhashi T, Takase K, Miyachi H, Yamada T, Ishibashi T, Higano S, Takahashi S. Treatment of in-stent restenosis with beraprost sodium: an experimental study of short- and intermediate-term effects in dogs. Clin Exp Pharmacol Physiol 2009; 36:1164-9. [PMID: 19473194 DOI: 10.1111/j.1440-1681.2009.05209.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1. The aim of the present study was to evaluate the inhibitory effects of the short-term administration of beraprost sodium, a stable prostaglandin I(2) analogue, on neointimal thickening after stenting. 2. To examine the immediate and short-term effects, Z-stents were placed in the iliac veins of 12 dogs, which were randomly assigned to either a beraprost-treated or control (saline) group. Beraprost (0.35 microg/kg per min) or saline (1.5 mL/min) was administered 30 min before stenting and was continued for 5 h thereafter. Platelet aggregation was measured before and after drug administration. At 3, 7 and 14 days after stenting, dogs were killed and immunohistochemical staining for proliferating cell nuclear antigen was used to quantify the proliferation of vascular smooth muscle cells (SMC). To evaluate intermediate-term effects, a Z-stent was placed in the right iliac vein in 10 dogs, followed by beraprost treatment. Three days later, a second Z-stent was placed contralaterally with saline infusion as a control. After 4 weeks, dogs were killed and neointimal thickness was measured under a light microscope to calculate the intima : media area ratio. 3. Platelet aggregation was more significantly suppressed in the beraprost-treated than in the control group (P = 0.01). In addition, SMC proliferation was significantly lower in the beraprost-treated group 7 and 14 days after stenting (P < 0.05). Over the intermediate term, the intima : media area ratio was significantly lower in the beraprost-treated vein compared with control (P < 0.05). 4. In conclusion, short-term beraprost treatment during stenting suppresses in situ platelet aggregation and SMC proliferation, thus reducing neointimal thickening.
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Affiliation(s)
- Kazumasa Seiji
- Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan.
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Pareta RA, Reising AB, Miller T, Storey D, Webster TJ. Increased endothelial cell adhesion on plasma modified nanostructured polymeric and metallic surfaces for vascular stent applications. Biotechnol Bioeng 2009; 103:459-71. [PMID: 19241389 DOI: 10.1002/bit.22276] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Techniques to regenerate the vasculature have risen considerably over the last few decades due to the increased clinical diagnosis of artery narrowing and blood vessel blockage. Although initially re-establishing blood flow, current small diameter vascular regenerative materials often eventually cause thrombosis and restenosis due to a lack of initial endothelial cell coverage on such materials. The objective of this in vitro study was to evaluate commonly used vascular materials (specifically, polyethylene terephthalate, polytetrafluoroethylene, polyvinyl chloride, polyurethane, nylon, commercially pure titanium, and a titanium alloy (Ti6Al4V)) modified using an ionic plasma deposition (IPD) process and a nitrogen ion implantation plasma deposition (NIIPD) process. Such surface modifications have been previously shown to create nanostructured surface features which mimic the natural nanostructured surface features of blood vessels. The modified and unmodified surfaces were characterized by scanning electron microscopy, atomic force microscopy and surface energy measurements. Furthermore, in vitro endothelial cell adhesion tests (a key first step for vascular material endothelialization) demonstrated increased endothelial cell adhesion on many modified (with IPD and NIIPD + IPD) compared to unmodified samples. In general, endothelial cell adhesion increased with nanoroughness and surface energy but demonstrated a decreased endothelial cell adhesion trend after an optimal coating surface energy value was reached. Thus, results from this study provided materials and a versatile surface modification process that can potentially increase endothelialization faster than current unmodified (conventional) polymer and metallic vascular materials.
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Affiliation(s)
- Rajesh A Pareta
- Department of Orthopedics, Brown University, Providence, Rhode Island 02912, USA
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França LHG, Pereira AH. Atualização sobre endopróteses vasculares (stents): dos estudos experimentais à prática clínica. J Vasc Bras 2008. [DOI: 10.1590/s1677-54492008000400010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Atualmente, o tratamento das doenças vasculares periféricas é uma das áreas da medicina de maior expansão. O número de intervenções vasculares aumenta e os resultados das novas técnicas endovasculares estão muito próximos aos das tradicionais cirurgias vasculares. Embora a angioplastia ofereça bons resultados em curto prazo, o implante de stents procura melhorar o sucesso do procedimento e estender o seu uso a um número maior de pacientes com doença vascular periférica. Entretanto, a sua utilização ainda é controversa. O implante de stents no sistema aorto-ilíaco tem bons resultados; porém, a sua indicação para as lesões femoro-poplíteas ainda é discutida. Além disso, o rápido desenvolvimento de stents e sua escolha para uso no sistema vascular periférico têm sido uma difícil tarefa para o cirurgião endovascular. Muitos fatores influenciam a escolha do stent, e um amplo conhecimento desse material é essencial. Tal escolha depende da avaliação pré-operatória, da localização e das características da lesão e também do uso do stent primário ou seletivo. Nesse trabalho, são realizadas revisão do histórico do desenvolvimento dos stents, desde os estudos experimentais até os ensaios clínicos e também discussão sobre a sua aplicação no tratamento das doenças vasculares periféricas.
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43
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Go DH, Joung YK, Park SY, Park YD, Park KD. Heparin‐conjugated star‐shaped PLA for improved biocompatibility. J Biomed Mater Res A 2008; 86:842-8. [DOI: 10.1002/jbm.a.31690] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Palmaz JC. Bring that pioneering spirit back! A 25-year perspective on the vascular stent. Cardiovasc Intervent Radiol 2007; 30:1095-8. [PMID: 17805924 PMCID: PMC2062489 DOI: 10.1007/s00270-007-9164-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 08/02/2007] [Indexed: 11/29/2022]
Affiliation(s)
- Julio C. Palmaz
- Department of Radiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MS 7800, San Antonio, TX 78229 USA
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45
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Liu M, Yue X, Dai Z, Xing L, Ma F, Ren N. Stabilized hemocompatible coating of nitinol devices based on photo-cross-linked alginate/heparin multilayer. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:9378-85. [PMID: 17663569 DOI: 10.1021/la7002996] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
A novel stabilized hemocompatible multicomponent coating was engineered by consecutive alternating adsorption of two polysaccharides, alginate (Alg) and heparin (Hep), onto a Nitinol surface via electrostatic interaction in combination with photoreaction in situ. For this purpose, a photosensitive cross-linker, p-diazonium diphenyl amine polymer (PA), was used as an interlayer between alginate and heparin. The optical intensity of UV/vis spectra increased linearly with the number of layers, indicating the buildup of a multilayer structure and uniform coating. Photo-cross-linking resulted in higher stability without compromising its catalytic capacity to promote antithrombin III (ATIII)-mediated thrombin inactivation. Chromogenic assays for heparin activity proved definitively that anticoagulation activity really comes from surface-bound heparin in multilayer film, not from solution-phase free heparin that has leaked from multilayer film. The activated partial thromboplastin time (aPTT) assay showed that both (PA/Hep)8- and (PA/Alg/PA/Hep)4-coated Nitinol were less thrombogenic than the uncoated one. Yet, the latter was found to be more stable under a continuous shaken wash. In addition, (PA/Alg/PA/Hep)4 film exhibited lower surface roughness and higher hydrophilicity than (PA/Hep)8. As a result, hemolysis of (PA/Alg/PA/Hep)4 (0.34 +/- 0.064%) was lower than (PA/Hep)8 (0.52 +/- 0.241%). The naked Nitinol and (PA/Hep)8-coated Nitinol showed relatively strong platelet adhesion. On the contrary, no sign of any cellular matter was seen on the (PA/Alg/PA/Hep)4 surface. It is believed that the phenomenon of interlayer diffusion resulted in blended structures, hence, the enhanced wettability and antifouling properties after the incorporation of alginate layers. It is likely that the cooperative effect of alginate and heparin led to the excellent blood compatibility of the (PA/Alg/PA/Hep)4 coating. To simplify, there is greater advantage in utilizing cross-linked alginate/heparin surfaces rather than merely the heparin surface for improving blood- and tissue-compatible devices.
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Affiliation(s)
- Meng Liu
- Nanobiotechnology and Biosensor Lab, Bio-X Center, Harbin Institute of Technology, Harbin, China
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46
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Wilczek K, Petelenz B, Strzała A, Marczewska B, Traczyk M, Poloński L. Dose perturbation caused by stents: experiments with a model 90Sr/90Y source. Cardiovasc Intervent Radiol 2007; 30:981-91. [PMID: 17710473 DOI: 10.1007/s00270-007-9148-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 06/12/2007] [Accepted: 06/21/2007] [Indexed: 10/22/2022]
Abstract
PURPOSE Biological effects of intravascular brachytherapy are very sensitive to discrepancies between the prescription and the applied dose. If brachytherapy is aimed at in-stent restenosis, shielding and shadowing effects of metallic stents may change the dose distribution relative to that produced by the bare source. The development of new generations of stents inspired us to a new experimental study in this field. The effect was studied for 14 stents which we have recently encountered in clinical practice. METHODS The model source was a continuous 20-mm column of (90)Sr/(90)Y solution sealed in a 1-mm-I.D. Plexiglas capillary. The dose distribution in the Plexiglas phantom was mapped using GafChromic MD-55-2 film. The stent masses varied from 2.5 to 25 mg; the strut thicknesses, from 0.075 to 0.15 mm; and the atomic numbers of stent materials, from 24 (Cr) to 79 (Au). RESULTS Dose perturbations depend on a variety of stent features. Local reduction of the mean dose rates near the reference distance (r(0) = 2 mm) varied from 11% to 47%. No simple correlation was found between these data and stent characteristics, but it seems that the atomic number of the stent material is less important than the strut thickness and mesh density. CONCLUSION The results provide a warning that clinical indications for in-stent radiation therapy must always be confronted with another aspect of the patient's history: the kind of implanted stent. Intravascular brachytherapy using pure beta sources may be recommended only for patients "wearing" light, thin-strut stents. The presence of thick-strut stents is a contraindication for this modality, due to excessive dose perturbation.
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Affiliation(s)
- Krzysztof Wilczek
- The Silesian Center for Heart Diseases, 3rd Chair and Clinical Hospital for Heart Diseases, Medical University of Silesia, 41-800 Zabrze, Szpitalna 2, Poland
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Affiliation(s)
- Jörg Lahann
- a Departments of Chemical Engineering, Materials Science and Engineering, and Macromolecular Science and Engineering , University of Michigan , Ann Arbor , Michigan
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Shin YH. Stent implantation to relieve secondary pulmonary venous stenosis in total anomalous pulmonary venous connection: case report. KOREAN JOURNAL OF PEDIATRICS 2007. [DOI: 10.3345/kjp.2007.50.9.919] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Youn Ho Shin
- Department of Pediatrics, Pochon CHA University College of Medicine, Korea
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Hughes M, Forauer AR, Lindh M, Cwikiel W. Conformation of Adjacent Self-expanding Stents: A Cross-Sectional In Vitro Study. Cardiovasc Intervent Radiol 2006; 29:255-9. [PMID: 16391952 DOI: 10.1007/s00270-005-0033-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We examined the proximal conformation of three commonly used self-expanding stents when the stents were deployed adjacent to one another in a tubular model, simulating a "kissing" stent technique. The stent pairs were evaluated by computed tomogrphy to determine the cross-sectional area excluded by the stents within the model. The mean areas associated with each stent pair were compared and significance evaluated by a t-test. A statistically significant difference was found when the area excluded by adjacent Wallstents was compared with both the Luminexx and SMART stents (p < 0.001 and p < 0.002, respectively). The difference in the area excluded and differences in conformation might play a role in the lower patencies that have been observed in "kissing" stent series.
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Affiliation(s)
- Marion Hughes
- Section of Vascular & Interventional Radiology, University of Michigan Medical Center, Ann Arbor, Michigan, USA
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Duncan IC, Fourie PA. Initial experience with intracranial stent-graft use. Technical notes. Interv Neuroradiol 2005; 11:131-9. [PMID: 20584492 DOI: 10.1177/159101990501100203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2005] [Accepted: 04/30/2005] [Indexed: 11/15/2022] Open
Abstract
SUMMARY We describe our initial experience with the placement of two premounted balloon expandable intracranial Jostent stent-grafts within the intracavernous internal carotid artery for the treatment of a symptomatic large intracavernous aneurysm in one case and a post-traumatic caroticocavernous fistula in the second. Among the initial technical complications we encountered were stent-graft migration and rapidly progressive intragraft thrombosis, with delayed sealing of the stent-graft coverings and exclusion of the pathologies relating to the use of abciximab in both cases. Despite these initial problems both cases had excellent short-term clinical outcomes with angiographic exclusion of both lesions by day three and good clinical and angiographic outcomes at one and two months respectively.
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Affiliation(s)
- I C Duncan
- Unitas Interventional Unit; Lyttelton, South Africa -
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