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Sample records for angioplastia con stent

  1. [Endovascular treatment of critical basilar stenosis with a Solitaire® stent device: a first experience in our centre].

    PubMed

    Mulero, Patricia; Cortijo-García, Elisa; Ruiz-Piñero, Marina; Pérez-Fernández, Santiago; Arenillas-Lara, Juan F; Martínez-Galdámez, Mario

    2014-08-01

    Introduccion. Aunque la arterioesclerosis intracraneal es una causa importante de ictus, la actitud terapeutica no esta claramente establecida. En este sentido, el estudio SAMMPRIS comparo el tratamiento medico intensivo con la angioplastia y colocacion de stent, con resultados favorables al tratamiento farmacologico. Estos resultados podrian, en parte, deberse al dispositivo utilizado (stent Wingspan ®). Caso clinico. Varon de 71 años con una estenosis grave de la arteria basilar, en quien se repetian episodios de focalidad neurologica transitoria a pesar del tratamiento con doble antiagregacion y estatinas. En estas circunstancias se decidio realizar una arteriografia terapeutica con angioplastia y colocacion de un stent Solitaire ® para optimizar resultados y se logro una estenosis residual del 40%. La evolucion fue favorable y los controles posteriores muestran una minima progresion. Conclusion. Segun nuestro conocimiento, este es el primer caso publicado de tratamiento de una estenosis critica de la arteria basilar mediante la colocacion de un stent Solitaire ®.

  2. Trombosis primaria de la descendente anterior en un paciente con síndrome de anticuerpos antifosfolípidos.

    PubMed

    Acuña-Valerio, Jorge; Peña-Duque, Marco Antonio; Contreras-Villaseñor, Álvaro

    2017-01-01

    El síndrome de anticuerpos antifosfolípidos es una situación clínica y bioquímica heterogénea. Presentamos el caso de un varón joven con antecedente de tromboembolia venosa que se presentó en esta ocasión por dolor precordial, con elevación del ST en el electrocardiograma. Fue llevado a sala de angiografía para realizar angioplastia primaria y se observó una oclusión total ostial de la descendente anterior. Se realizó aspiración manual del trombo. No se realizó angioplastia con balón ni stent. En la angiografía de control a las 48 horas se observó ausencia de trombo y de placas aterosclerosas, lo cual se corroboró mediante ultrasonido intracoronario. Antiphospholipid antibody syndrome is a heterogeneous clinical and biochemical entity. We present the case of a young male with history of venous thromboembolism. This time he presents because of chest ischemic pain associated with ST segment elevation. He was taken to the cath lab to perform a primary percutaneous coronary intervention and a total occlusion of the left anterior descending artery was noted. Successful thrombus aspiration was performed. No stent was deployed. He was taken to the cath lab for a second look angiography and no atherosclerotic lesions were observed, which was confirmed by intravascular ultrasound.

  3. [Pyeloureteral stenting using nitinol stents].

    PubMed

    Guliev, B G; Zagazezhev, A M

    2016-11-01

    To test the effectiveness of nitinol stents in restoring patency of pyeloureteral segment (PUS). Endoureteral nitinol stents were used in 54 patients. The indications for stenting were recurrent strictures of upper urinary tract and ureteral tumor obstruction in 34 and 20 patients, respectively. In 9 (16.6%) of them, including 4 women and 5 men aged 28-65 years, stenting was performed for extensive recurrent PUS strictures. In 8 patients extensive strictures resulted from various surgical interventions on the PUS. In 2 patients, PUS narrowing was caused by open pyelolithotomy, in 6 patients by pyeloplasty, both open (4) and laparoscopic (2). A female patient with solitary right kidney and Bourneville - Pringle disease of the PUS received two metal prostheses. In all cases, nitinol stents were adequately installed in PUS. Hematuria was observed in 1 patient. During the follow-up period of 8 to 60 months, the results of stenting were considered good in 6 (66.7%) and satisfactory in 2 (22.2%) patients. At month 10, 1 (11.1%) patient developed the stent obstruction by proliferative tissue and underwent ureteroscopy with recanalization of the nitinol stent. The patient with Bourneville - Pringle disease was found to have a stone formed in the renal pelvic end of the endoprosthesis; she underwent percutaneous nephrolithotripsy. In another patient a lower calyceal stone migrated and wedged into the proximal end of the stent. The stone was extracted using percutaneous nephroscopy. Pyeloureteral stenting is an effective method to restore patency of the PUS in patients with extensive recurrent strictures. For adequate functioning of the stents, they need to be of optimal length and correctly installed.

  4. Angioplasty and Vascular Stenting

    MedlinePlus

    ... Drug-coated (also called drug-eluting) stents have recently been approved for clinical use by the U.S. ... you notify the MRI department that you have recently had a stent. Although stents used today may ...

  5. Symptomatic stent cast.

    PubMed

    Keohane, John; Moore, Michael; O'Mahony, Seamus; Crosbie, Orla

    2008-02-01

    Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

  6. New stents for SFA.

    PubMed

    MINAR, E; SCHILLINGER, M

    2009-10-01

    Endovascular stent implantation was introduced to femoropopliteal procedures almost two decades ago. Initial results with balloon-expandable stainless steel stents and self expanding Elgiloy stents, however, were disappointing. In particular, recurrence rates after long-segment femoropopliteal stenting were rather high, in the range of 60% to 80% at 1 year. After years of stagnation, recent developments in femoropopliteal stent technology have been promising. Self-expanding nitinol stents have been evaluated in several prospective studies. Initial problems with stent fractures seem to be resolved using second-generation devices. The second generation of Nitinol stents have an enhanced flexibility particularly also in axial direction due to a reduction of cell interconnections and a more spiral orientation of the interconnections. However, until now there is no proof of any impact of the stent design on restenosis rate. Otherwise, stenting has been shown to be beneficial compared to balloon angioplasty especially in longer femoropopliteal lesions. The superior fracture resistance of the latest stent generation in combination with the production of long nitinol stents of up to 20 cm in length allow that more difficult and complex lesions can be treated endovascularly. The main unresolved problem with femoropopliteal stenting is the treatment of instent restenosis. Future concepts to further improve long-term patency after femoropopliteal stenting are therefore under investigation, including drug-eluting stents (DES), biodegradable stents, and coated stent-grafts. Stent grafts appear to be a viable option for the treatment of complex superficial femoral artery lesions, with comparable outcomes to prosthetic above-knee femoropopliteal bypass surgery. Concerning DES, we have to wait for the results of the ongoing studies.

  7. Airway stents in children.

    PubMed

    Nicolai, T

    2008-04-01

    Airway obstruction in children is a rare, but difficult clinical problem, with no clear agreement on optimal therapeutic approach. Stenting of the airway has been used successfully in adults, and is an attractive alternative in children. Fundamental differences of pediatric compared to adult use include the benign nature of most stenoses, the narrow and soft airways of children, the required long-term tolerance and adaptation to growth. These differences may significantly alter the therapeutic balance, calling into question the precise role stents play in the treatment of airway obstruction in children. Stent placement can be technically demanding but is not exceedingly difficult. Experience is necessary to select the proper size and type of stent. Metal stents usually achieve airway patency and clinical improvement in the majority of cases, while this is less frequently the case with silicone stents. Some complications such as granulation and secretion retention seem to occur in most children after stent implantation. Unfortunately, severe complications including death have been reported in a significant proportion of children. Stent related mortality can be estimated at 12.9% from published data, but these include complication centered reports. The initial euphoria for airway stents in children has largely abated and most authors agree that they should only be employed in circumstances with no good alternatives. It is crucial that all surgical and medical alternatives are considered and the decision to place a stent is not made because other options are overlooked or not available locally. Stent use in a palliative setting has also been reported and is probably reasonable. Stents will only allow limited adaptation for the growth of pediatric airways by balloon dilatation. All metal stents should be considered as potentially permanent, and removal sometimes may only be possible through a surgical and sometimes risky approach.

  8. Update in urethral stents.

    PubMed

    Bahouth, Z; Meyer, G; Yildiz, G; Nativ, O; Moskovitz, B

    2016-10-01

    Urethral stents were first introduced in 1988, and since then, they have undergone significant improvements. However, they did not gain a wide popularity and their use is limited to a small number of centers around the world. Urethral stents can be used in the entire urethra and for various and diverse indications. In the anterior urethra, it can be used to treat urethral strictures. In the prostatic urethra, they can be used for the treatment of prostatic obstruction, including benign, malignant and iatrogenic prostatic obstruction. Moreover, although not widely used, it can be also applied for the treatment of posterior urethral stricture and bladder neck contracture, usually resulting in urinary incontinence and the need for subsequent procedures. Our main experience are with Allium urethral stents, and as such, we provide the latest updates in urethral stents with special emphasis on the various types of Allium urethral stents: bulbar, prostatic and bladder neck stents.

  9. An Update to Hepatobiliary Stents

    PubMed Central

    Moy, Brian T.; Birk, John W.

    2015-01-01

    Endoscopic stent placement is a common primary management therapy for benign and malignant biliary strictures. However, continuous use of stents is limited by occlusion and migration. Stent technology has evolved significantly over the past two decades to reduce these problems. The purpose of this article is to review current guidelines in managing malignant and benign biliary obstructions, current endoscopic techniques for stent placement, and emerging stent technology. What began as a simple plastic stent technology has evolved significantly to include uncovered, partially covered, and fully covered self-expanding metal stents (SEMS) as well as magnetic, bioabsorbable, drug-eluting, and antireflux stents.1 PMID:26357636

  10. Biodegradable Ureteral Stents

    NASA Astrophysics Data System (ADS)

    Chew, Ben H.; Hadaschik, Boris A.; Paterson, Ryan F.; Lange, Dirk

    2008-09-01

    Ureteral stents have been associated with painful symptoms and require a secondary procedure for removal if the suture tether is removed. Biodegradable stents have been attempted in the past, but are no longer used since they resulted in histological inflammation or unpredictable variability in degradation time. This article reviews past degradable materials used in both the prostatic urethra and ureter as well as identifies a new degradable ureteral stent that lasts between 2 to 4 weeks in a porcine model.

  11. Coronary artery stent (image)

    MedlinePlus

    ... with a balloon catheter and expands when the balloon is inflated. The stent is then left there to help keep the artery open. ... with a balloon catheter and expands when the balloon is inflated. The stent is then left there to help keep the artery open.

  12. Gastrointestinal Stent Update

    PubMed Central

    2010-01-01

    The use of self-expanding metallic stents in the upper gastrointestinal tract, placed under radiologic imaging or endoscopic guidance, is the current treatment of choice for the palliation of malignant gastrointestinal outlet obstructions. Advances in metallic stent design and delivery systems have progressed to the stage where this treatment is now considered a minimally invasive therapy. Metallic stent placement will broaden further into the field of nonsurgical therapy for the gastrointestinal tract. To date, metallic stents placed in the esophagus, gastric outlet, colorectum, and bile ducts are not intended to be curative, but rather to provide a palliative treatment for obstructions. The evolution of metallic stent technology will render such procedures not only palliative but also therapeutic, by enabling local drug delivery, and the use of biodegradable materials will reduce procedure-related complications. PMID:21103290

  13. Forgotten urological stent.

    PubMed

    Bhuiyan, Z H; Bhuiyan, N I; Khan, S A; Tawhid, M H; Islam, M F

    2011-10-01

    "Forgotten" Ureteral stent DJ stent related complication is not uncommon even in the era of modern urology in the developed world. In this context we have undertaken a retro-prospective study in relation to its various causes, complications, management and prevention of forgotten stents in a single teaching institute. The study period was from January'04 to December'09. The sample size was 60. The effect of "forgotten stent" in our study reflects mild UTI to various complications including severe renal failure. We had approached all of our cases judiciously using various modalities of minimal access endourological techniques either alone or in combinations with successful outcome. The study concluded that it is vary easy to prevent "forgotten stent" and so its complications. However if we confront such unwanted complications that could be managed successfully with the use of endourological techniques. We did not use other techniques like laparoscopy and open surgery in this study.

  14. [Stent for neurovascular diseases].

    PubMed

    Sakai, Nobuyuki; Sakai, Chiaki

    2009-09-01

    A stent is a medical device that can provide scaffolding to vessels and organ walls to keep the arteries open. Different types of stents have been used in the filed of neurovascular diseases, such as atherosclerosis and aneurysms. Carotid artery stenting (CAS) was approved in 2007 in Japan, and it has been widely used as an alternative to carotid endarterectomy (CEA) for treating severe carotid artery stenosis. According to current approval, the indications of carotid artery stenting are observed in high-surgical-risk patients, patients with more than 50% symptomatic stenosis, and those with more than 80% asymptomatic stenosis. The use of nickel-titanium (nitinol) crush-resistant self-expanding stents (Precise) and emblic-protection devices (Angioguard XP) has been approved. Intracranial atherosclerotic disease have frequently posed a risk for recurrent stroke despite the intensive medical treatment. The design of the Wingspan stent system is different from that of balloon-expandable stents. Target lesions are predilated with an undersized angioplasty balloon, followed by stent deployment. Another important indication is for intracranial aneurysms. Since the discovery Guglielmi dechatable coils (GDC) in the early 1990s, endovascular treatment has been drastically improved all over the world. However, a high recurrence rate is observed when large and wide-necked aneurysms are treated with detachble coils. The application of self-expanding stents such as Neuroform, Enterprize, or LEO, is effective for packing coils into the aneurysm, and flow modification effect can be achieved for the curative reconstruction of the parent arteries. Further reserch will confirm the application of stents for the treatment of cerebrovascular disease.

  15. Predictors of early stent occlusion among plastic biliary stents.

    PubMed

    Khashab, Mouen A; Kim, Katherine; Hutfless, Susan; Lennon, Anne Marie; Kalloo, Anthony N; Singh, Vikesh K

    2012-09-01

    A major disadvantage of plastic biliary stents is their short patency rates. The aim of this study was to identify predictors of early stent occlusion among patients receiving conventional plastic biliary stents. Early stent occlusion was defined as worsening cholestatic liver test results of a severity sufficiently significant to warrant ERCP with stent exchange prior to the planned stent exchange, or as symptoms of cholangitis. The association of cumulative stent diameter, demographics, stricture location, procedure indication, Charlson comorbidity index, history of prior early stent occlusion, presence of gallbladder, and performance of sphincteromy with the occurrence of early stent occlusion was studied using logistic regression and multivariate analysis. Our patient cohort comprised 343 patients (mean age 59.3 years) who underwent 561 ERCP procedures with the placement of one or more plastic biliary stents (mean number of stents per procedure 1.2, mean total diameter of stents per procedure 12 Fr). Early stent occlusion occurred in 73 (13 %) procedures. Female gender was protective against early stent occlusion (adjusted OR 0.54, 95 % CI 0.32-0.90, p = 0.02), while hilar stricture location was independently associated with a significantly increased risk of early stent occlusion (adjusted OR 3.41, 95 % CI 1.68-6.90, p = 0.0007). Early occlusion of conventional biliary stents occurred in 13 % of cases. While female gender decreased the risk of early stent occlusion, hilar stricture location was a significant predictor of early stent occlusion. Our results suggest that physicians should consider early elective stent exchange in patients with hilar strictures.

  16. Stent intussusception after thromboaspiration through a platinum chrome stent: a particular case of longitudinal stent deformation.

    PubMed

    Mila, Rafael; Vignolo, Gustavo; Trujillo, Pedro

    2015-04-01

    The need to improve stent deliverability has led to the development of thinner and more flexible stents. However, there is concern about decreased longitudinal strength. The number of longitudinal stent deformation reports has dramatically increased. We report a case of stent longitudinal deformation after thromboaspiration through a new generation platinum chrome bare metal stent. Images show an "intussusception effect," an extreme form of the previously described "concertina deformation," as the mechanism of shortening. Since stent technology is constantly evolving, newer devices will probably be designed to have less susceptibility to longitudinal stent deformation.

  17. Endovascular Gene Delivery from a Stent Platform: Gene- Eluting Stents

    PubMed Central

    Fishbein, Ilia; Chorny, Michael; Adamo, Richard F; Forbes, Scott P; Corrales, Ricardo A; Alferiev, Ivan S; Levy, Robert J

    2015-01-01

    A synergistic impact of research in the fields of post-angioplasty restenosis, drug-eluting stents and vascular gene therapy over the past 15 years has shaped the concept of gene-eluting stents. Gene-eluting stents hold promise of overcoming some biological and technical problems inherent to drug-eluting stent technology. As the field of gene-eluting stents matures it becomes evident that all three main design modules of a gene-eluting stent: a therapeutic transgene, a vector and a delivery system are equally important for accomplishing sustained inhibition of neointimal formation in arteries treated with gene delivery stents. This review summarizes prior work on stent-based gene delivery and discusses the main optimization strategies required to move the field of gene-eluting stents to clinical translation. PMID:26225356

  18. Endovascular Gene Delivery from a Stent Platform: Gene- Eluting Stents.

    PubMed

    Fishbein, Ilia; Chorny, Michael; Adamo, Richard F; Forbes, Scott P; Corrales, Ricardo A; Alferiev, Ivan S; Levy, Robert J

    A synergistic impact of research in the fields of post-angioplasty restenosis, drug-eluting stents and vascular gene therapy over the past 15 years has shaped the concept of gene-eluting stents. Gene-eluting stents hold promise of overcoming some biological and technical problems inherent to drug-eluting stent technology. As the field of gene-eluting stents matures it becomes evident that all three main design modules of a gene-eluting stent: a therapeutic transgene, a vector and a delivery system are equally important for accomplishing sustained inhibition of neointimal formation in arteries treated with gene delivery stents. This review summarizes prior work on stent-based gene delivery and discusses the main optimization strategies required to move the field of gene-eluting stents to clinical translation.

  19. A New Stent Graft

    PubMed Central

    Nishi, S.; Nakayama, Y.; Ueda, H.; Ishikawa, M.; Matsuda, T.

    2000-01-01

    Summary The use of stents improves the result after balloon coronary angioplasty. Restenosis due to neointimal hyperplasia and proliferation of smooth muscle cells are, however; a concern. In the present report, we studied the prevention of restenosis to allow endothelial cell migration and growth to proceed through micropores using our developed stent graft with micropored segmented polyurethane (SPU) thin film in a normal beagle model. Our developed stent graft was made from Palmaz stent and micropored SPU thin film. The SPU film was arranged into four different micropore densities around the circumference: no micropores, arrangement 4; micropores of 30µm in diameter with an orderly distance of 250µm; (arrangement 1), 500µm; (arrangement 2) and 125µm (arrangement 3) between the neighboring two pores. Micropores were made using the Excimer laser ablation technique. The Palmaz stent was wrapped with micropored film, sutured, and glued with DMF (dimethyl formamide) under aid of a microscope. These stents were placed in the common carotid arteries of beagles (n = 5). They were sacrificed at 1 month, and a histological study and scanning electron microscopy study were performed for evaluation of endoluminal endothelialization. In 10 arteries applied with stent grafts, there was no severe stenosis although it did occur to some extent. All stented arteries were patent. Endothelial cell migration and growth through micropores were observed histologically on micropored SPU thin film in this model, which did not affect the intraluminal diameter. In most non-porous regions, significant thrombi were found between the SPU film and the neointimal layer. On the other hand, in the porous region, little thrombosis was observed except in the lowest density region. In 125µm of distance between two neighboring pores, the neointimal layer was the thinnest, which was suitable for wide intraluminal space after placement of a stent graft. Endothelial cell migration and growth

  20. Process for making electroformed stents

    DOEpatents

    Hines, Richard A.

    2000-02-01

    This invention is directed to an expandable stent useful for implantation into an artery or the like. The stents are made using electroforming techniques in which an electrically-conductive mandrel is coated with a suitable resist material, after which the resist is exposed to an appropriate light pattern and frequency so as to form a stent pattern in the resist. The mandrel is then electroplated with a suitable stent material. The mandrel is etched away once a sufficient layer of stent material is deposited, leaving a completed stent.

  1. Renal Artery Stent Outcomes

    PubMed Central

    Murphy, Timothy P.; Cooper, Christopher J.; Matsumoto, Alan H.; Cutlip, Donald E.; Pencina, Karol M.; Jamerson, Kenneth; Tuttle, Katherine R.; Shapiro, Joseph I.; D’Agostino, Ralph; Massaro, Joseph; Henrich, William; Dworkin, Lance D.

    2016-01-01

    BACKGROUND Multiple randomized clinical trials comparing renal artery stent placement plus medical therapy with medical therapy alone have not shown any benefit of stent placement. However, debate continues whether patients with extreme pressure gradients, stenosis severity, or baseline blood pressure benefit from stent revascularization. OBJECTIVES The study sought to test the hypothesis that pressure gradients, stenosis severity, and/or baseline blood pressure affects outcomes after renal artery stent placement. METHODS Using data from 947 patients with a history of hypertension or chronic kidney disease from the largest randomized trial of renal artery stent placement, the CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) study, we performed exploratory analyses to determine if subsets of patients experienced better outcomes after stent placement than the overall cohort. We examined baseline stenosis severity, systolic blood pressure, and translesion pressure gradient (peak systolic and mean) and performed interaction tests and Cox proportional hazards analyses for the occurrence of the primary endpoint through all follow-up, to examine the effect of these variables on outcomes by treatment group. RESULTS There were no statistically significant differences in outcomes based on the examined variables nor were there any consistent nonsignificant trends. CONCLUSIONS Based on data from the CORAL randomized trial, there is no evidence of a significant treatment effect of the renal artery stent procedure compared with medical therapy alone based on stenosis severity, level of systolic blood pressure elevation, or according to the magnitude of the transstenotic pressure gradient. (Benefits of Medical Therapy Plus Stenting for Renal Atherosclerotic Lesions [CORAL]; NCT00081731) PMID:26653621

  2. Tracheobronchial stents in children.

    PubMed

    Antón-Pacheco, Juan L

    2016-06-01

    Tracheobronchial obstruction is infrequent in children and still remains a challenging matter of concern. Management alternatives vary from conservative treatment to complex surgical techniques or endoscopic interventional procedures. Airway stenting in children is relatively recent and follows the trail of the experience in adult patients. Nevertheless, there are basic differences between both age groups like the benign nature of most obstructions and the small size of the pediatric airway. These specific features raise the issues of the precise role of tracheobronchial stenting in children and the selection of the most adequate device. Stents fall into four main categories according to the material they are made of: metallic, plastic, hybrid, and biodegradable. Each type has its own advantages and drawbacks so the ideal stent is not yet available. Despite increasing experience with stenting, definite clinical criteria for their use in children are yet to be established. Even so, there seems to be a basic general agreement that stents may play a role in particular clinical settings in which there are no other therapeutic options. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Coronary Stent Infection Presented as Recurrent Stent Thrombosis

    PubMed Central

    Lai, Chih-Hung; Lin, Yung-Kai; Lee, Wen-Lieng

    2017-01-01

    Percutaneous transluminal coronary angioplasty with metal stent placement has become a well-developed treatment modality for coronary stenotic lesions. Although infection involving implanted stents is rare, it can, however, occur with high morbidity and mortality. We describe herein a case of an inserted coronary stent that was infected and complicated with recurrent stent thrombosis, pseudoaneurysm formation and severe sepsis. Despite repeated intervention and bypass surgery, the patient died from severe sepsis. PMID:28120580

  4. Current status and future direction of biodegradable metallic and polymeric vascular scaffolds for next-generation stents.

    PubMed

    Im, Seung Hyuk; Jung, Youngmee; Kim, Soo Hyun

    2017-09-15

    Because of the increasing incidence of coronary artery disease, the importance of cardiovascular stents has continuously increased as a treatment of this disease. Biodegradable scaffolds fabricated from polymers and metals have emerged as promising materials for vascular stents because of their biodegradability. Although such stent framework materials have shown good clinical efficacy, it is difficult to decide whether polymers or metals are better vascular scaffolds because their properties are different. Therefore, there are still obstacles in the development of biodegradable vascular scaffolds in terms of improving clinical efficacy. This review analyzes the pros and cons of current stent materials with respect to five key factors for next-generation stent and discusses methods of improvement. Furthermore, we discuss biodegradable electronic stents with electrical conductivity, which has been considered unimportant until now, and highlight electrical conductivity as a key factor in the development of next-generation stents. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Future developments in biliary stenting

    PubMed Central

    Hair, Clark D; Sejpal, Divyesh V

    2013-01-01

    Biliary stenting has evolved dramatically over the past 30 years. Advancements in stent design have led to prolonged patency and improved efficacy. However, biliary stenting is still affected by occlusion, migration, anatomical difficulties, and the need for repeat procedures. Multiple novel plastic biliary stent designs have recently been introduced with the primary goals of reduced migration and improved ease of placement. Self-expandable bioabsorbable stents are currently being investigated in animal models. Although not US Food and Drug Administration approved for benign disease, fully covered self-expandable metal stents are increasingly being used in a variety of benign biliary conditions. In malignant disease, developments are being made to improve ease of placement and stent patency for both hilar and distal biliary strictures. The purpose of this review is to describe recent developments and future directions of biliary stenting. PMID:23837001

  6. [Stents in iliac vascular changes].

    PubMed

    Gross-Fengels, W; Friedmann, G; Fischbach, R; Erasmi, H; Bulling, B

    1991-01-01

    The results of 79 iliac stent placements in 64 patients are reported. The technical success rate was 96%. The systolic pressure gradient dropped from 44 mmHg before to 2.8 mmHg after stent placement. This differed significantly as compared to a group treated by conventional PTA (gradient 5.8 mmHg). The cumulative patency after 18-20 months was 90%. Angiographic controls up to 19 months after "stenting" demonstrated only one secondary stent occlusion. Iliac stents therefore are a very valuable supplement to classic PTA.

  7. Antiplatelet therapy in patients undergoing coronary stenting

    PubMed Central

    ten Berg, J.M.; van Werkum, J.W.; Heestermans, A.A.C.M.; Jaarsma, W.; Hautvast, R.M.A.; den Heijer, P.; de Boer, M.J.

    2006-01-01

    Background Anticoagulation after coronary stenting is essential to prevent stent thrombosis. Drug-eluting stents, which are the preferred therapy, may be associated with a higher tendency for stent thrombosis. Methods Patients who underwent coronary stent placement and presented with late stent thrombosis are described. Results Eight patients with stent thrombosis are presented. Early discontinuation of the antithrombotic medication is associated with the occurrence of these complications. Conclusion Long-term antithrombotic therapy seems essential to prevent stent thrombosis, especially for patients treated with drug-eluting stents. PMID:25696663

  8. Heterogeneous Intravascular Ultrasound Findings of Stent Thrombosis

    PubMed Central

    Morofuji, Toru; Inaba, Shinji; Aisu, Hiroe; Takahashi, Kayo; Saito, Makoto; Higashi, Haruhiko; Yoshii, Toyofumi; Sumimoto, Takumi

    2017-01-01

    Objective The underlying mechanisms of stent thrombosis are not completely understood. Methods We experienced 12 definite stent thrombosis cases (1 early, 1 late, and 10 very late) at our hospital from July 2011 to April 2016 and evaluated the possible causes of stent thrombosis by intravascular ultrasound (IVUS). Results Five different potential morphological causes of stent thrombosis (neoatherosclerosis, stent malapposition, stent fracture, edge dissection, and stent underexpansion) were detected by IVUS in 10 cases (83.3%); in 1 of the remaining 2 cases, the discontinuation of antithrombotic drugs resulted in early stent thrombosis without abnormal IVUS findings. Of the 12 stent thrombosis cases, 4 occurred at a bare-metal stent (average time from stent implantation, 106 months); in all 12, significant neointimal hyperplasia was observed on IVUS, and 2 had plaque ruptures at an in-stent or proximal reference. Malapposed stent struts were observed in three very-late stent thromboses, and all of these underwent sirolimus-eluting stent implantation. Stent thrombosis due to mechanical (stent fracture) or procedure-related complications (edge dissection and stent underexpansion) was observed in three cases. Conclusion In patients with stent thrombosis, heterogeneous findings were observed in IVUS. This IVUS case series illustrates the possible mechanisms of stent thrombosis. PMID:28154268

  9. [Physical properties of Strecker stents].

    PubMed

    Okuda, Y; Sawada, S; Morioka, N; Kodani, K; Ihaya, T; Tanigawa, N; Kobayashi, M; Hashimoto, M; Oouchi, Y; Shimatani, Y

    1995-02-01

    Strecker stent is a balloon-expandable metallic stent that is made of knitted tantalum wire mesh in order to Maintain flexibility. Therefore, the prosthesis is well suited to irregular and tortuous tube organs. We performed several physical experiments using 8 mm and 6 mm diameter stents made of 0.1 mm diameter wire filament. The bearing power of the 8 mm diameter stent against the circumferential compression pressure was divided into two groups, that is, 77-100% and under 66% of expansile rate. The capacity bearing the circumferential compression pressure of the latter group was greater than that of the former. Further, the bearing power of the 6 mm diameter stent was greater than that of the 56% expansile rate of the 8 mm diameter stent. The smaller the expansile rate of the stent, the smaller the minimum radius of curvature within the limits of the stent's plastic. To evaluate the suitability of the stent in clinical use, we made two projections on the inner surface of rubber tubes, and the stents were placed into the rubber tubes at different expansile rates. We evaluated the degree of contact of the stents against the rubber wall by taking soft X-ray photographs. The stents showed good suitability under the condition of incomplete expansion. For the above reasons, we concluded that, from the view-point of bearing power, the stent should be placed in the full expansile state. From the viewpoint of contact against the vessel wall, the stent should be placed in the incomplete expansile state.

  10. Overlap stenting for in-stent restenosis after carotid artery stenting

    PubMed Central

    Nishihori, Masahiro; Ohshima, Tomotaka; Yamamoto, Taiki; Goto, Shunsaku; Nishizawa, Toshihisa; Shimato, Shinji; Izumi, Takashi; Kato, Kyozo

    2016-01-01

    ABSTRACT Our aim was to assess the clinical safety and efficacy of overlap stenting for in-stent restenosis after carotid artery stenting. The study was conducted between July 2008 and February 2015. A database of consecutive carotid artery stenting procedures was retrospectively assessed to identify the cases of in-stent restenosis that were treated with overlap stenting under proximal or distal protection. The clinical and radiological records of the patients were then reviewed. Of the 155 CAS procedures in 149 patients from the database, 6 patients met the inclusion criteria. All the 6 patients were initially treated with moderate dilatation because of the presence of an unstable plaque. The technical success rate of the overlap stenting was 100%, with no 30-day mortality or morbidity. In addition, there was no further in-stent restenosis during a follow-up period of over 12 months. These results indicated that overlap stenting for in-stent restenosis after carotid artery stenting was both safe and effective in our cohort. PMID:27303101

  11. [Rescue treatment in acute thrombosis of intracranial stents].

    PubMed

    Pumar, José M; Banguero, Alexandra; Arias-Rivas, Susana; Blanco, Miguel; Rodríguez-Yáñez, Manuel; Sucasas, Paula; Blanco, Miguel; Castiñeira-Mourenza, José A; Vázquez-Herrero, Fernando

    2014-02-01

    Introduccion. La trombosis aguda intrastent es una complicacion potencialmente grave en el stenting intracraneal. Es primordial determinar cual es la terapia mas adecuada en las trombosis intrastent. Caso clinico. Mujer de 58 años, el primer caso de trombosis aguda de un stent intracraneal, que fue tratada con exito mediante fibrinolisis tras la implantacion de un dispositivo diversificador de flujo (Silk) en un aneurisma basilar fusiforme. Conclusion. La administracion de abciximab como tratamiento de rescate parece segura en los casos de formaciones de trombos agudos intrastent.

  12. Coronary covered stents.

    PubMed

    Kilic, Ismail Dogu; Fabris, Enrico; Serdoz, Roberta; Caiazzo, Gianluca; Foin, Nicolas; Abou-Sherif, Sara; Di Mario, Carlo

    2016-11-20

    Covered stents offer an effective bail-out strategy in vessel perforations, are an alternative to surgery for the exclusion of coronary aneurysms, and have a potential role in the treatment of friable embolisation-prone plaques. The aim of this manuscript is to offer an overview of currently available platforms and to report results obtained in prior studies.

  13. Stent-Induced Esophageal Perforation: Treatment by Means of Placing a Second Stent After Removal of the Original Stent

    SciTech Connect

    Jung, Gyoo-Sik Park, Sung-Dal; Cho, Young Duk

    2008-05-15

    A case of esophageal perforation caused by a retrievable covered stent is presented. The distal end of the stent was protruding into the mediastinum, which made it impossible to negotiate a guidewire through the stent into the distal esophagus. The stent was successfully removed with use of a stent retrieval set, and esophageal perforation was treated with a second, covered stent with a good result. Fatality associated with this complication might be prevented by virtue of the retrievability of the stent we used. This result points to the effectiveness of a retrievable stent for the palliative treatment of malignant esophageal stricture.

  14. Mechanical Characteristics of Composite Knitted Stents

    SciTech Connect

    Tokuda, Takanori Shomura, Yuzo; Tanigawa, Noboru; Kariya, Shuji; Komemushi, Atsushi; Kojima, Hiroyuki; Sawada, Satoshi

    2009-09-15

    We used metal wires and fibers to fabricate a composite knitted stent and then compare the mechanical characteristics of this stent with those of a pure metallic stent of the same construction in order to develop a stent that offers a comparable degree of expandability as metallic stents but can be used for highly curved lesions that cannot be treated using metallic stents. We fabricated two types of composite knitted stent (N-Z stents), using nitinol wire with a diameter of 0.12 mm and polypara-phenylene-benzobisoxazole (PBO) multifilament fiber (Zyron AS; Toyobo, Osaka, Japan). Stents were knitted into a cylindrical shape using the same textile pattern as a Strecker stent. Two loop lengths (L) of nitinol wire were used in the N-Z stents: L = 1.84 mm (N-Z stent L = 1.84) and L = 2.08 mm (N-Z stent L = 2.08). For the sake of comparison, we fabricated a metallic stent of nitinol using the same textile pattern (N-N stent L = 1.92). We applied a radial compression force diametrically to each stent and applied a bending force diametrically at the free end of a stent with one end fixed in order to evaluate the relationship between stent elasticity and load values. In addition, we macroscopically evaluated the generation of kinks when the stent was bent 180{sup o}. The radial compressive force when the stent diameter was reduced by 53% was 6.44 N in the case of N-Z stent L = 1.84, 6.14 N in the case of N-Z stent L = 2.08, and 4.96 N in the case of N-N stent L = 1.92 mm. The composite stent had a radial compressive force higher than that of a metallic stent. The restoring force to longitudinal direction at a 90{sup o} bending angle was 0.005 N for N-Z stent L = 1.84, 0.003 N for N-Z stent L = 2.08, and 0.034 N for N-N stent L = 1.92. The restoring force of the composite stent was significantly lower. Finally, the composite stent generated no definitive kinks at a bending angle of 180{sup o}, regardless of loop length. However, the N-N stent clearly produced kinks, causing

  15. Ureteroscopic removal of forgotten ureteral stent

    PubMed Central

    Kawahara, Takashi; Ishida, Hiroaki; Kubota, Yoshinobu; Matsuzaki, Junichi

    2012-01-01

    A 69-year-old female had a right ureteral stent placed due to ureteral stricture resulting from cervical cancer in March 2008. The ureteral stent migrated to the ureter and was not exchanged. A new ureteral stent was inserted, and was exchanged every 3 months. The patient was referred to our department to remove the forgotten ureteral stent. In January 2012, her old ureteral stent was removed ureteroscopically, and no ureteral stent encrustation was found. PMID:22707678

  16. Delayed complications after flow-diverter stenting: reactive in-stent stenosis and creeping stents.

    PubMed

    Cohen, José E; Gomori, John Moshe; Moscovici, Samuel; Leker, Ronen R; Itshayek, Eyal

    2014-07-01

    We assessed the frequency and severity of changes in stent configuration and location after the treatment of intracranial aneurysms, and patterns of in-stent stenosis. We retrospectively reviewed data for consecutive aneurysm patients managed with endovascular implantation of flow-diverter stents (Silk Flow Diverter [Balt Extrusion, Montmorency, France] and Pipeline Embolization Device [ev3/Coviden, Minneapolis, MN, USA]) from October 2011 to July 2012. Routine 2, 6, 9-12, and 16-20 month follow-up angiograms were compared, with a focus on changes in stent configuration and location from immediately after deployment to angiographic follow-up, and the incidence and development of in-stent stenosis. Thirty-four patients with 42 aneurysms met inclusion criteria. The Silk device was implanted in 16 patients (47%, single device in 15), the Pipeline device in 18 (53%, single device in 16). On first follow-up angiography, in-stent stenosis was observed in 38% of Silk devices and 39% of Pipeline devices. In-stent stenosis was asymptomatic in 12 of 13 patients. One woman presented with transient ischemic attacks and required stent angioplasty due to end tapering and mild, diffuse in-stent stenosis. Configuration and location changes, including stent creeping and end tapering were seen in 2/16 patients (13%) with Silk devices, and 0/18 patients with Pipeline devices. We describe stent creeping and end tapering as unusual findings with the potential for delayed clinical complications. In-stent stenosis, with a unique behavior, is a frequent angiographic finding observed after flow-diverter stent implant. The stenosis is usually asymptomatic; however, close clinical and angiographic monitoring is mandatory for individualized management. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Wave reflection at a stent.

    PubMed

    Crespo, Antonio; García, Javier; Manuel, Fernando

    2013-01-01

    A simple analytical expression has been derived to calculate the characteristics of a wave that reflects at a stent implanted in a uniform vessel. The stent is characterized by its length and the wave velocity in the stented region. The reflected wave is proportional to the time derivative of the incident wave. The reflection coefficient is a small quantity of the order of the length of the stent divided by the wavelength of the unstented vessel. The results obtained coincide with those obtained numerically by Charonko et al. The main simplifications used are small amplitude of the waves so that equations can be linearized and that the length of the stent is small enough so that the values of the wave functions are nearly uniform along the stent. Both assumptions hold in typical situations.

  18. [Stent Grafting for Aortic Dissection].

    PubMed

    Uchida, Naomichi

    2016-07-01

    The purpose of stent graft for aortic dissection is to terminate antegrade blood flow into the false lumen through primary entry. Early intervention for primary entry makes excellent aortic remodeling and emergent stent grafting for complicated acute type B aortic dissection is supported as a class I. On the other hand stent grafting for chronic aortic dissection is controversial. Early stent grafting is considered with in 6 months after on-set if the diameter of the descending aorta is more than 40 mm. Additional interventions for residual false lumen on the downstream aorta are still required. Stent graft for re-entry, candy-plug technique, and double stenting, other effective re-interventions were reported. Best treatment on the basis of each anatomical and physical characteristics should be selected in each institution. Frozen elephant trunk is alternative procedure for aortic dissection without the need to take account of proximal anatomical limitation and effective for acute type A aortic dissection.

  19. Biliary stents in the millennium.

    PubMed

    Srinivasan, Indu; Kahaleh, Michel

    2011-11-01

    Biliary stents have now been in use for over two decades. Although a plethora of literature has been published on them, this review article is unique in its attempt to summarize important landmark trials and their implications on the management of various pancreatico-biliary disorders. This article will cover the various types of stents currently being used, established and upcoming indications, techniques of placement, and complications associated with stent use.

  20. Angioplasty and stent placement - heart

    MedlinePlus

    PCI; Percutaneous coronary intervention; Balloon angioplasty; Coronary angioplasty; Coronary artery angioplasty; Percutaneous transluminal coronary angioplasty; Heart artery dilatation; Angina - stent placement; ...

  1. Reducing In-Stent Restenosis

    PubMed Central

    McDonald, Robert A.; Halliday, Crawford A.; Miller, Ashley M.; Diver, Louise A.; Dakin, Rachel S.; Montgomery, Jennifer; McBride, Martin W.; Kennedy, Simon; McClure, John D.; Robertson, Keith E.; Douglas, Gillian; Channon, Keith M.; Oldroyd, Keith G.; Baker, Andrew H.

    2015-01-01

    Background Drug-eluting stents reduce the incidence of in-stent restenosis, but they result in delayed arterial healing and are associated with a chronic inflammatory response and hypersensitivity reactions. Identifying novel interventions to enhance wound healing and reduce the inflammatory response may improve long-term clinical outcomes. Micro–ribonucleic acids (miRNAs) are noncoding small ribonucleic acids that play a prominent role in the initiation and resolution of inflammation after vascular injury. Objectives This study sought to identify miRNA regulation and function after implantation of bare-metal and drug-eluting stents. Methods Pig, mouse, and in vitro models were used to investigate the role of miRNA in in-stent restenosis. Results We documented a subset of inflammatory miRNAs activated after stenting in pigs, including the miR-21 stem loop miRNAs. Genetic ablation of the miR-21 stem loop attenuated neointimal formation in mice post-stenting. This occurred via enhanced levels of anti-inflammatory M2 macrophages coupled with an impaired sensitivity of smooth muscle cells to respond to vascular activation. Conclusions MiR-21 plays a prominent role in promoting vascular inflammation and remodeling after stent injury. MiRNA-mediated modulation of the inflammatory response post-stenting may have therapeutic potential to accelerate wound healing and enhance the clinical efficacy of stenting. PMID:26022821

  2. Nasal packing and stenting

    PubMed Central

    Weber, Rainer K.

    2011-01-01

    Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue. PMID:22073095

  3. Stent evolution for peripheral arterial disease.

    PubMed

    Lejay, A; Thaveau, F; Girsowicz, E; Georg, Y; Heim, F; Durand, B; Chakfé, N

    2012-02-01

    Endovascular treatment and stent implantation for peripheral arterial disease have been proposed for over 20 years. However, the first experiments with stainless stents were relatively disappointing. The first improvement consisted in the introduction of nitinol self-expanding stents. This technology allowed an initial improvement of clinical performances, but the first generation of nitinol stents demonstrated a relatively high rate of fractures. Better knowledge of arterial biomechanics and advances in technology allowed to propose a second generation of nitinol stents with improved flexibility, which decreased the rates of fracture. In-stent restenosis related to neointimal hyperplasia has also led to the development of new concepts to improve patency rates after stenting: drug-eluting stents (coated-stents), biodegradable stents, and covered stents. These technologies will help to treat more complex lesions in the future, but we are still waiting for results of ongoing studies.

  4. iStent® Trabecular Microbypass Stent: An Update

    PubMed Central

    Resende, Arthur Fernandes; Patel, Neal Sanjay; Waisbourd, Michael; Katz, L. Jay

    2016-01-01

    Due to the high rates of complications and failure experienced with current glaucoma procedures, there is a continuous search for a safer and more effective glaucoma surgery. A new class of procedures termed minimally invasive glaucoma surgeries (MIGS) aim to fill this void by offering an alternative method of IOP reduction associated with markedly reduced complication rates and shorter recovery times. The iStent, a trabecular microbypass stent, is a MIGS device that has quickly gained popularity. The device allows aqueous humor to directly drain from the anterior chamber into Schlemm's canal by bypassing an obstructed trabecular meshwork. This review examines publications about the iStent, focusing on the device's efficacy, safety, and cost when a single iStent or multiple iStents are implanted in combination with cataract surgery or as a solo procedure. Current data suggest that the iStent is a safe and effective tool in the management of mild-to-moderate glaucoma, notable for its limited complications and absence of serious adverse events following implantation. As valuable experience is gained performing ab interno MIGS, increasing familiarity with angle anatomy and iStent placement, and as newer stent designs are developed, there is promise of continual improvement in the surgical management of glaucoma. PMID:27413541

  5. Carotid artery stenting: which stent for which lesion?

    PubMed

    Bosiers, Marc; Deloose, Koen; Verbist, Jürgen; Peeters, Patrick

    2005-01-01

    The different geometries and working principles of carotid stents (nitinol or cobalt chromium, open- or closed-cell configuration) provide each product with unique functional properties. The individual characteristics of each device may make it an attractive choice in one circumstance but render it less desirable in other situations. In approximately 75% of all procedures, all types of stents will achieve similar outcomes, making adequate device selection unnecessary. For the remaining quarter, careful preoperative screening is mandatory. In addition to eventual access issues, the choice of the optimal carotid stent depends mainly on arterial anatomy and lesion morphology. When treating a tortuous anatomy, stents with a flexible and comformable open-cell configuration are preferred. In arteries with a significant mismatch between common carotid artery and internal carotid artery diameter, cobalt chromium (Elgiloy) or tapered nitinol stents are selected. Lesions with suspected high emboligenicity are best covered with stents with a closed-cell configuration, whereas highly calcified lesions need treatment with nitinol stents. Thorough knowledge of the characteristics, advantages and disadvantages, and working principles of the different available stents is mandatory to optimally select the materials to be used for patients eligible for carotid revascularization.

  6. In vitro evaluation of stent patency and in-stent stenoses in 10 metallic stents using MR angiography.

    PubMed

    Hamer, O W; Borisch, I; Paetzel, C; Nitz, W R; Seitz, J; Feuerbach, S; Zorger, N

    2006-08-01

    In vitro study to investigate the suitability of contrast enhanced magnetic resonance angiography (CEMRA) for determination of stent patency and grading of in-stent stenoses in 10 metallic stents. The Acculink carotid, DynaLink, Easy Wallstent, JostentSelfX XF, Luminexx, Omnilink, sinus-SuperFlex, SMART, Symphony and ZA stent were separately placed in a vascular phantom. Dedicated stenoses inside the stents generated a concentric lumen narrowing of 50%. CEMRA was performed for each stent. Signal loss inside the stents and artificial lumen narrowing were assessed objectively using the evaluation software of the MR imager. Moreover, three blinded observers determined visibility of stent patency and in-stent stenoses subjectively on a 3-point scale and graded in-stent stenoses. Loss of signal intensity within the stent lumen ranged between 90% (Wallstent) and 5% (ZA), artificial lumen narrowing between 56% (Symphony) and 22% (ZA). For the Symphony and Wallstent, visibility of patency and in-stent stenoses was impaired and the observers' grading exaggerated the degree of stenoses (by 23% and 33%, respectively). For the remainder of stents, patency and stenoses were visible and stenoses were graded accurately (less than 10% discrepancy from reference standard). In this in vitro study, eight of 10 stents presented with MRI characteristics which enabled determination of stent patency and accurate grading of clinically relevant in-stent stenoses.

  7. Stent fabric fatigue of grafts supported by Z-stents versus ringed stents: an in vitro buckling test.

    PubMed

    Lin, Jing; Wang, Lu; Guidoin, Robert; Nutley, Mark; Song, Ge; Zhang, Ze; Du, Jia; Douville, Yvan

    2014-03-01

    Stent-grafts externally fitted with a Z-shaped stents were compared to devices fitted with ringed stents in an in vitro oscillating fatigue machine at 200 cycles per minute and a pressure of 360 mmHg for scheduled durations of up to 1 week. The devices fitted with Z-stents showed a considerably lower endurance limit to buckling compared to the controls. The contact between the apexes of adjacent Z-stents resulted in significant damage to the textile scaffolds and polyester fibers due to the sharp angle of the Z-stents. The ringed stents did not cause any fraying in the textile scaffolds.

  8. Heparin-Coated Coronary Stents.

    PubMed

    van Der Giessen WJ; van Beusekom HM; Larsson; Serruys

    1999-09-01

    The development of the heparin-coated (HC)-stent should be viewed against the backdrop of the early unfavorable results with noncoated stents in the pre-intravascular ultrasound and pre-ticlopidine era. Notwithstanding, results of pilot and randomized trials show a surprisingly low incidence of (sub)acute stent thrombosis under challenging circumstances, such as acute coronary syndromes. Considering the quite low incidence of early complications with noncoated second-generation stents, it may require large trials to prove the clinical efficacy of the heparin- coating against noncoated devices. However, even if the "added value" of the heparin-coating will never be clinically proven, it has helped to enhance the penetration of stent therapy in interventional cardiology. Unlike the situation in 1992, very few cardiologists will now disagree with the statement that stents contribute to the state-of-the-art treatment of patients with angina pectoris or acute myocardial infarction. A preliminary comparison of available trials also suggests that the heparin-coated Palmaz-Schatz stent (Cordis Corp., Waterloo, Belgium) is as effective as the noncoated stent plus abciximab treatment.

  9. A new removable airway stent

    PubMed Central

    Amundsen, Tore; Sørhaug, Sveinung; Leira, Håkon Olav; Tyvold, Stig Sverre; Langø, Thomas; Hammer, Tommy; Manstad-Hulaas, Frode; Mattsson, Erney

    2016-01-01

    Background Malignant airway obstruction is a feared complication and will most probably occur more frequently in the future because of increasing cancer incidence and increased life expectancy in cancer patients. Minimal invasive treatment using airway stents represents a meaningful and life-saving palliation. We present a new removable airway stent for improved individualised treatment. Methods To our knowledge, the new airway stent is the world's first knitted and uncovered self-expanding metal stent, which can unravel and be completely removed. In an in vivo model using two anaesthetised and spontaneously breathing pigs, we deployed and subsequently removed the stents by unravelling the device. The procedures were executed by flexible bronchoscopy in an acute and a chronic setting – a ‘proof-of-principle’ study. Results The new stent was easily and accurately deployed in the central airways, and it remained fixed in its original position. It was easy to unravel and completely remove from the airways without clinically significant complications. During the presence of the stent in the chronic study, granulation tissue was induced. This tissue disappeared spontaneously with the removal. Conclusions The new removable stent functioned according to its purpose and unravelled easily, and it was completely removed without significant technical or medical complications. Induced granulation tissue disappeared spontaneously. Further studies on animals and humans are needed to define its optimal indications and future use. PMID:27608269

  10. Are Aortic Stent Grafts Safe in Pregnancy?

    PubMed Central

    Khandanpour, Nader; Mehta, Tapan A.; Adiseshiah, M.; Meyer, Felicity J.

    2015-01-01

    Aortic stent grafts are increasingly used to treat aortic aneurysms and also other aortic pathologies. The safety of aortic stent grafts in pregnancy has never been studied or reported. We report on two cases of aortic stent grafts in pregnant women and discuss the effect of pregnancy on these aortic stent grafts. PMID:26229702

  11. Developments in metallic biodegradable stents.

    PubMed

    Hermawan, H; Dubé, D; Mantovani, D

    2010-05-01

    Interest in metallic degradable biomaterials research has been growing in the last decade. Both scientific journals and patent databases record a high increase in publications in this area. Biomedical implants with temporary function, such as coronary stents, are the targeted applications for this novel class of biomaterials. It is expected that stents made of degradable biomaterials, named biodegradable stents, will provide a temporary opening into a narrowed arterial vessel until the vessel remodels and will progressively disappear thereafter. Biodegradable stents made of metal have recently been progressed into preclinical tests in humans after their first introduction in early 2000s. By referring to patents and journal publications, this paper reviews the developments in biodegradable stents, with emphasis on those made of metals, starting from the first design ideas to validation testing.

  12. Prevalence, factors, and clinical impact of self-expanding stent fractures following iliac artery stenting.

    PubMed

    Higashiura, Wataru; Kubota, Yasushi; Sakaguchi, Shoji; Kurumatani, Norio; Nakamae, Mitsuhiro; Nishimine, Kiyoshi; Kichikawa, Kimihiko

    2009-03-01

    To evaluate the prevalence, factors, and clinical impact of self-expanding stent fracture following iliac artery stenting. A review of the endovascular registry database for our department showed 353 patients with occlusive diseases of the iliac artery who underwent stenting between 1997 and 2007. While clinical data and images were retrospectively reviewed for all patients, 165 patients who underwent self-expanding stenting and plain radiograph with >or=6-months follow-up were analyzed. Mean follow-up was 43 months for 305 stents (elgiloy, n = 83; nitinol, n = 222) implanted in 216 iliac arteries. The mean duration until the last imaging study was 38 months. Items concerning prevalence of stent fracture, factors associated with fracture, and outcomes for patients with stent fracture were analyzed. Stent fracture was detected in 11 of 216 iliac arteries (5.1%). In stent-based analysis, 11 of 305 stents (3.6%) showed stent fracture, classified as type I in 2 stents, type II in 3 stents, type III in 4 stents, type IV in 1 stent, and type V in 1 stent. Stent fracture was detected in 11 of 222 nitinol stents (5.0%), but no Elgiloy stents. Cox proportional hazards regression model indicated stenting for chronic occlusion as a risk factor associated with nitinol stent fracture (hazard ratio [HR] = 6.09, P = 0.008, 95% confidence interval [CI] 1.59-23.3). Cumulative primary patency rates in iliac arteries with and without fractured stents were 90% and 91% at 8 years (P = .80), respectively. Fracture of self-expanding stents is rare in iliac arteries, but stenting for chronic occlusion represents a risk factor for fracture. Fractures of stents placed in iliac arteries rarely affect patency.

  13. Ureteral stents: new ideas, new designs

    PubMed Central

    Al-Aown, Abdulrahman; Kyriazis, Iason; Kallidonis, Panagiotis; Kraniotis, Pantelis; Rigopoulos, Christos; Karnabatidis, Dimitrios; Petsas, Theodore; Liatsikos, Evangelos

    2010-01-01

    Ureteral stents represent a minimally invasive alternative to preserve urinary drainage whenever ureteral patency is deteriorated or is under a significant risk to be occluded due to extrinsic or intrinsic etiologies. The ideal stent that would combine perfect long-term efficacy with no stent-related morbidity is still lacking and stent usage is associated with several adverse effects that limit its value as a tool for long-term urinary drainage. Several new ideas on stent design, composition material and stent coating currently under evaluation, foreseen to eliminate the aforementioned drawbacks of ureteral stent usage. In this article we review the currently applied novel ideas and new designs of ureteral stents. Moreover, we evaluate potential future prospects of ureteral stent development adopted mostly by the pioneering cardiovascular stent industry, focusing, however, on the differences between ureteral and endothelial tissue. PMID:21789086

  14. Plastic biliary stents for malignant biliary diseases.

    PubMed

    Huibregtse, Inge; Fockens, Paul

    2011-07-01

    Plastic biliary endoprostheses have not changed much since their introduction more than 3 decades ago. Although their use has been challenged by the introduction of metal stents, plastic stents still remain commonly used. Much work has been done to improve the problem of stent obstruction but without substantial clinical success. In this review, the authors discuss the history of plastic biliary stent development and the current use of plastic stents for malignant biliary diseases.

  15. StentBoost Visualization for the Evaluation of Coronary Stent Expansion During Percutaneous Coronary Interventions.

    PubMed

    Cura, Fernando; Albertal, Mariano; Candiello, Alfonsina; Nau, Gerardo; Bonvini, Victor; Tricherri, Hernan; Padilla, Lucio T; Belardi, Jorge A

    2013-12-01

    Inadequate stent implantation is associated with stent thrombosis and restenosis. StentBoost can enhance stent visualization and evaluate stent expansion. Currently, there are limited comparison studies between StentBoost and intravascular ultrasound (IVUS). We aimed to test the correlation and agreement between IVUS and StentBoost measurements. From December 2010 to December 2011, 38 patients (54 stents) were analyzed using IVUS and StentBoost. Minimal stent diameter and proximal and distal edge stent diameter were compared between imaging techniques using Pearson correlation and Bland-Altman scatter plot. There was good correlation between StentBoost and IVUS measurements regarding minimal stent diameter (p < 0.001 in all stent portions) and an optimal agreement between IVUS and StentBoost, while lesser agreement was found between IVUS and quantitative coronary angiography. The assessment of stent implantation using StentBoost showed an adequate correlation and agreement with IVUS. This easily applicable angiographic technique can be used to guide stent implantation.

  16. Present and future of endovascular SFA treatment: stents, stent-grafts, drug coated balloons and drug coated stents.

    PubMed

    Bosiers, M; Deloose, K; Verbist, J; Peeters, P

    2008-04-01

    The current evolution towards treating more complex femoropopliteal lesions as seen in the renewed TASC II recommendations clearly reflects the continuous evolutions in femoropopliteal stent design. Recent stent design improvements focus on decreasing stent fractures rates which can negatively impact patency rates. By rearranging strut alignment towards helical connecting bridges or full helical stent designs, stent designers have successfully improved the fracture resistance of their stents. The superior fracture resistance of the latest stent generation in combination with the production of long nitinol stents of up to 20 cm in length allow that more difficult and complex lesions can be treated endovascularly. The continuous perfection of nitinol stent platforms followed by the transfer of coronary technologies (e.g. active coatings) towards peripheral devices might broaden the indications for the minimal invasive strategy towards TransAtlantic Inter-Society Consensus (TASC) II C&D lesions.

  17. Drug-Eluting Stents: Do They Increase Heart Attack Risk?

    MedlinePlus

    ... general, drug-eluting stents are preferred over bare-metal stents for most people. Drug-eluting stents are ... keep the blockage from recurring compared to bare metal stents. Plus, studies show the latest drug-eluting ...

  18. [Larynx: implants and stents].

    PubMed

    Sittel, C

    2009-05-01

    There is a wide variety of devices and materials to be implanted into the human larynx. Some are intended to remain only for a period of time, like laryngeal stents. If removal is not intended the device meets the definition for a medical implant. The majority of implants is used for the treatment of unilateral vocal fold immobility. There a 2 types of implants serving this purpose: Implants in a stricter sense are devices of solid material, which are brought into the paraglottic space through a window in the laryngeal framework (medialization thyroplasty). Several different products are presented in this review. In contrast, there are different substances available for endoscopic injection into the paralyzed vocal fold (injection laryngoplasty). Since some of these substances show a corpuscular consistency and a high viscosity they need to be deposited into the lateral paraglottic space. Therefore, the term "injectable implants" has been coined for these materials. The different substances available are discussed in detail in this review. Laryngeal stents are primarily used in the early postoperative phase after open reconstruction of the larynx. The different devices available on the market are described with their specific characteristics and intended use.

  19. Biodegradable stents in gastrointestinal endoscopy

    PubMed Central

    Lorenzo-Zúñiga, Vicente; Moreno-de-Vega, Vicente; Marín, Ingrid; Boix, Jaume

    2014-01-01

    Biodegradable stents (BDSs) are an attractive option to avoid ongoing dilation or surgery in patients with benign stenoses of the small and large intestines. The experience with the currently the only BDS for endoscopic placement, made of Poly-dioxanone, have shown promising results. However some aspects should be improved as are the fact that BDSs lose their radial force over time due to the degradable material, and that can cause stent-induced mucosal or parenchymal injury. This complication rate and modest clinical efficacy has to be carefully considered in individual patients prior to placement of BDSs. Otherwise, the price of these stents therefore it is nowadays an important limitation. PMID:24605020

  20. Optimal stent design for drug delivery.

    PubMed

    Rogers, Campbell D K

    2004-01-01

    The efficacy and safety of drug-eluting coronary stents might differ depending on the pharmacologic agents and stent delivery systems used. Recent research has focused on the various constituents of drug-delivery stents, including the stent backbone, materials used as drug-delivery vehicles, and the physicochemical properties of the pharmacotherapeutic agents themselves. Metal stents coated with an outer layer of polymer (bioabsorbable or non-bioabsorbable) can be drug-loaded, thus providing more controlled and sustained drug delivery and allowing more optimal drug-tissue interactions. Among the next generation of drug-eluting stents will be a stent that uses the non-bioabsorbable polymer phosphorylcholine to release the sirolimus analogue ABT-578; another stent will use a highly deliverable cobalt-chromium metal alloy stent platform and, for the first time, a bioabsorbable polymeric coating (thin-film polylactic acid) for drug encapsulation and release.

  1. In Stent Restenosis Predictors after Carotid Artery Stenting

    PubMed Central

    Cosottini, Mirco; Michelassi, Maria Chiara; Bencivelli, Walter; Lazzarotti, Guido; Picchietti, Silvia; Orlandi, Giovanni; Parenti, Giuliano; Puglioli, Michele

    2010-01-01

    Purpose. The long-term efficacy of carotid artery stenting is debated. Predictors of stent restenosis are not fully investigated. Our aim was to assess the incidence of long term restenosis after CAS and to identify some predictors of restenosis. Methods. We retrospectively selected 189 treated patients and we obtained the survival Kaplan-Meier curves for overall survival, for freedom from stroke or death and from restenosis. To correlate clinical, radiological, and procedural variables to stent restenosis, an univariate analysis was performed while to determine independent predictors of restenosis, a multivariate analysis was applied. Results. At 1, 3, and 5 years, the cumulative overall survival rate was 98%, 94%, and 92% with a cumulative primary patency rate of 87%, 82.5%, and 82.5%. The percentage residual stenosis after CAS and multiple stents deployment were independent predictors of restenosis, while diabetes and tumors are suggestive but not significant predictors of restenosis. Conclusions. In our CAS experience, encouraging long-term results seem to derive from both neurological event free rate and restenosis incidence. Adequate recanalization of the treated vessel is important to limit the development of stent restenosis. Multiple stents deployment, and with less evidence, diabetes, or neoplasms has to be considered to facilitate restenosis. PMID:20798894

  2. Emergency cricothyroidotomy following tracheobronchial stenting.

    PubMed

    Cavinato, Simon Robert; Denning, Mike; Madden, Brendan P

    2017-02-24

    A man aged 51 years was referred for tracheobronchial stenting after a poorly differentiated oesophageal carcinoma had progressed to cause stridor. Bronchoscopy revealed a left vocal cord palsy and tumour infiltration into the trachea. A tracheobronchial stent was placed, and after distal migration was endoscopically resited. Returning from theatre, the patient developed severe upper airway obstruction that progressed to cause CO2 narcosis and loss of consciousness. A rapid sequence induction was initiated, and a Glidescope revealed bilateral vocal cord palsy with severe oedema causing an inability to pass a tube or stylet. Tracheostomy was attempted above the suprasternal notch but was obstructed by the stent. Oxygen saturations dropped steadily, reaching as low as 38%. Emergency cricothyroidotomy was performed, compliant with DAS guidelines, that proved successful. The stent was removed, which was blocked with blood and secretions, and tracheostomy was placed 2 days later. The patient made a full neurological recovery.

  3. Advances in Ureteral Stent Design

    NASA Astrophysics Data System (ADS)

    Denstedt, John D.

    2007-04-01

    Ureteral stents are commonly used in urolithiasis patients for relief of obstruction or in association with stone treatments such as ureteroscopy and extracorporeal shock wave lithotripsy. There are currently many different bulk materials and coatings available for the manufacture of ureteral stents, however the ideal material has yet to be discovered. All potential biomaterials must undergo rigorous physical and biocompatibility testing before commercialization and use in humans. Despite significant advances in basic science research involving biocompatibility issues and biofilm formation, infection and encrustation remain associated with the use of biomaterials in the urinary tract. There have been many significant advances in the design of ureteral stents in recent years and these will be highlighted along with a discussion of future aspects of biomaterials and use of stents in association with urolithiasis.

  4. Everolimus-eluting stents in interventional cardiology

    PubMed Central

    Townsend, Jacob C; Rideout, Phillip; Steinberg, Daniel H

    2012-01-01

    Bare metal stents have a proven safety record, but limited long-term efficacy due to in-stent restenosis. First-generation drug-eluting stents successfully countered the restenosis rate, but were hampered by concerns about their long-term safety. Second generation drug-eluting stents have combined the low restenosis rate of the first generation with improved long-term safety. We review the evolution of drug-eluting stents with a focus on the safety, efficacy, and unique characteristics of everolimus-eluting stents. PMID:22910420

  5. Novel side branch ostial stent.

    PubMed

    Chen, Shao-Liang; Lv, Shu-Zheng; Kwan, Tak W

    2009-04-01

    Bifurcation lesions are technically challenging and plagued by a high incidence of restenosis, especially at the side branch orifice, which results in a more frequent need for revascularization during the follow-up period. This report discusses two clinical experiences with a novel side branch ostial stent, the BIGUARD stent, designed for the treatment of bifurcation lesions; procedural success with no in-hospital complications was observed in types IVb and Ia lesions.

  6. Colorectal Stents: Current Status

    PubMed Central

    Lee, Jeong-Mi

    2015-01-01

    A self-expandable metal stent (SEMS) is an effective and safe method for the decompression of colon obstruction. Based on recent evidence, colorectal SEMS is now recommended for the palliation of patients with colonic obstruction from incurable colorectal cancer or extracolonic malignancy and also as a bridge to surgery in those who are a high surgical risk. Prophylactic SEMS insertion in patients with no obstruction symptoms is not recommended. Most colorectal SEMS are inserted endoscopically under fluoroscopic guidance. The technical and clinical success rates of colorectal SEMS are high, and the complication rate is acceptable. Advances in this technology will make the insertion of colorectal SEMS better and may expand the indications of colorectal SEMS in the future. PMID:26064818

  7. Percutaneous cholangioscopy in obstructed biliary metal stents

    SciTech Connect

    Hausegger, Klaus A.; Mischinger, Hans J.; Karaic, Radenko; Klein, Guenther E.; Kugler, Cristian; Kern, Robert; Uggowitzer, Martin; Szolar, Dieter

    1997-05-15

    Purpose. To reevaluate the reasons for the occlusion of self-expanding biliary metal stents, on the basis of cholangioscopic findings. Methods. Percutaneous transhepatic cholangioscopy (PTCS) was performed in 15 patients with obstructed biliary Wallstents. The reason for stent insertion was a malignant obstruction in 14 patients; 1 had a benign biliary stricture. Conventional noncovered stents had been inserted in 12 patients; in 3 cases a polyurethane-covered prototype Wallstent had been used. Stent occlusions occurred after 1-55 months. PTCS was performed with a 2.3-mm endoscope through an 11 Fr sheath. Biopsies were taken via the working channel of the endoscope. Results. In all patients with noncovered stents the inner surface of the stent was highly irregular with seaweed-like protrusions (biopsy-proven granulation tissue). Stent incorporation varied from absent (n=1) to subtotal (n=8), but was always incomplete, no matter how long the stent had been in place. Tumor ingrowth was histologically proven in 2 patients. One patient had a large occluding concrement at the proximal end of the stent. In patients with covered stents, the inner surface appeared more regular; however, viable granulation tissue was found inside two stents and tumor ingrowth in one of them. Conclusion. PTCS showed that incorporation of the stent is virtually always incomplete. The factors contributing most to stent occlusion are the buildup of granulation tissue, bile sludge, and tumor overgrowth. Stone formation and tumor ingrowth can also be important, although less common causes of occlusion. A polyurethane stent covering could not prevent tumor ingrowth in one patient and the buildup of viable granulation tissue inside the stent in two further patients; mean stent patency in the three patients with such a stent was 3 months.

  8. Forgotten Ureteral Stents: An Avoidable Morbidity.

    PubMed

    Murtaza, Badar; Alvi, Sarwar

    2016-03-01

    To assess the clinical presentation of forgotten ureteral stents and highlight the etiological factors resulting in the retention of these stents. Observational study. Department of Urology, Armed Forces Institute of Urology, Rawalpindi, from January 2010 to June 2011. Thirty-eight patients, with forgotten ureteral stents, retained for more than 6 months duration, were enrolled. A detailed evaluation was performed, along with the questions regarding the patients' opinion about the ureteral stents. They were specially asked whether they knew about the stents or were they formally informed regarding the stents. Subsequently, the patients were managed according to their clinical condition. The male to female ratio was 2.1:1 aged 23 - 69 years, mean being 40.24 ±12.59 years. The time of presentation after the ureteral stenting was 7 - 180 months (mean = 28.89 ±33.435 years). Seven patients (18.4%) reported with chronic kidney disease, including ESRD in two cases. Recurrent UTI was seen in 28 cases (73.6%), calculus formed over the stents in 20 cases (52.6%), and stent fragmented in 5 patients (13.1%). Majority of patients, (n = 23, 60.5%), were not even aware of the placement of these stents while 8 (21.0%) knew but were reluctant about its removal. In 3 cases (7.8%), the relatives knew about the stent but never informed the patients. The stent had been removed in 2 cases (5.2%), but the other broken fragment was missed. One case (2.6%) each had a misconception about the permanent placement of the stents like cardiac stents and regarding degradation of the stents in situ. Forgotten ureteral stents produce clinical features ranging from recurrent UTI to ESRD. This preventable urological complication is primarily due to the unawareness or ignorance of the patients and their relatives regarding the stent.

  9. Biliary Stent Migration with Duodenal Perforation

    PubMed Central

    Yaprak, Muhittin; Mesci, Ayhan; Colak, Taner; Yildirim, Bulent

    2008-01-01

    Intestinal perforation from a migrated biliary stent is a known complication of endoscopic biliary stent placement. We present a case of stent migration and resultant duodenal perforation after stent placement for a malignant biliary stricture in a 52-year-old woman. We review the current literature on the diagnosis and management of stent migration and intestinal perforation after endoscopic stent placement for biliary strictures. A plain abdominal radiograph is necessary for early diagnosis of biliary stent migration. If a stent becomes lodged in the gastrointestinal tract, endoscopic or operative extraction of the stent is necessary to prevent subsequent intestinal perforation and peritonitis. Intestinal perforation secondary to biliary stent dislocation should be considered in all patients presenting with fever and abdominal pain after biliary stent insertion. Any abnormality that prevents stent migration through the intestinal tract such as gastroenterostomy, abdominal wall hernia, extensive adhesions or colonic divertucula may be a contraindication for insertion of a plastic biliary stent because of increased perforation risk. PMID:25610053

  10. Assessment of coronary stents by 64-slice computed tomography: in-stent lumen visibility and patency.

    PubMed

    Kong, Ling-Yan; Jin, Zheng-Yu; Zhang, Shu-Yang; Zhang, Zhu-Hua; Wang, Yi-Ning; Song, Lan; Zhang, Xiao-Na; Zhang, Yun-Qing

    2009-09-01

    To assess lumen visibility of coronary stents by 64-slice computed tomography (CT) coronary angiography, and determine the value of 64-slice CT in non-invasive detecting of in-stent restenosis after coronary artery stent implantation. Totally, 60 patients (54 males, aged 57.0+/-12.7 years) and 105 stents were investigated by 64-slice CT at a mean interval of 20.0+/-16.6 months after coronary stents implantation. Axial multi-planar reconstruction images of the stents and curved-planar reconstruction images through the median of the stents were reconstructed for evaluating stent image quality on a 5-point scale (1=excellent, 5=non-assessable), and stent lumen diameter was detected. Conventional coronary angiography was performed in 18 patients, and 32 stents were evaluated. Image quality was good to excellent on average (score 1.71+/-0.76). Stent image quality score was correlated to heart rate (r=0.281, P<0.01) and stent diameter (r=-0.480, P<0.001). All the stents were assessable in lumen visibility with an average visible lumen diameter percentage of 60.7%+/-13.6%. Visible lumen diameter percentage was correlated to heart rate (r=-0.193, P<0.05), stent diameter (r=0.403, P<0.001), and stent image quality score (r=-0.500, P<0.001). Visible lumen diameter percentage also varied depending on the stent type. In comparison with the conventional coronary angiography, 4 of 6 in-stent stenoses were correctly detected. The sensitivity and specificity for the detection of in-stent stenosis were 66.7% and 84.6%, respectively. Using a 64-slice CT, the stent lumen is partly visible in most of the stents. And 64-slice CT may be useful in the assessment of stent patency.

  11. Clinical outcomes of compromised side branch (stent jail) after coronary stenting with the NIR stent.

    PubMed

    Bhargava, B; Waksman, R; Lansky, A J; Kornowski, R; Mehran, R; Leon, M B

    2001-11-01

    Acute side-branch (SB) compromise or occlusion stent jail after native coronary stenting is a matter of concern. Attempts at maintaining SB patency can be a technical challenge. The purpose of this study was to determine the clinical impact of SB compromise or occlusion in patients undergoing stenting of parent vessel lesions. We evaluated in-hospital and long-term clinical outcomes (death, Q-wave myocardial infarction, and repeat revascularization rates at 6 months) in 318 consecutive patients undergoing NIR stent implantation across an SB. Based on independent angiographic analysis, 218 (68.6%) patients had no poststent SB compromise, 85 (26.7%) patients had narrowed SB (> 70% narrowing, without total occlusion), and 15 (4.7%) patients had an occluded SB after stent implantation. The baseline patient and lesion characteristics were similar between the groups. Procedural success was 100%. Patients with SB occlusion had a higher stents/lesion ratio (P < 0.006). Side-branch occlusion was associated with higher in-hospital ischemic complications (Q-wave myocardial infarction, 7%; non-Q-wave myocardial infarction, 20%; P < 0.05) compared to patients with SB compromise or normal SB. At 6-month follow-up, there was a trend for more myocardial infarctions in the group with SB occlusion during the index procedure (Q-wave myocardial infarction, 7% vs. 1% in the narrowed and 0% in normal SB; P = 0.09). However, late target lesion revascularization and mortality were similar in the three groups (P = 0.91). SB occlusion after parent vessel stenting is associated with more frequent in-hospital Q-wave and non-Q-wave myocardial infarctions. However, with the NIR stent, side-branch compromise or occlusion does not influence late (6 month) major adverse events, including death, myocardial infarction, or need for repeat revascularization.

  12. Two Cases of Immediate Stent Fracture after Zotarolimus-Eluting Stent Implantation

    PubMed Central

    Lee, Pil Hyung; Lee, Seung-Whan; Lee, Jong-Young; Kim, Young-Hak; Lee, Cheol Whan; Park, Duk-Woo; Park, Seong-Wook

    2015-01-01

    Drug-eluting stent (DES) implantation is currently the standard treatment for various types of coronary artery disease. However, previous reports indicate that stent fractures, which usually occur after a period of time from the initial DES implantation, have increased during the DES era; stent fractures can contribute to unfavorable events such as in-stent restenosis and stent thrombosis. In our present report, we describe two cases of zotarolimus-eluting stent fracture: one that was detected six hours after implementation, and the other case that was detected immediately after deployment. Both anatomical and technical risk factors contributed to these unusual cases of immediate stent fracture. PMID:25653706

  13. Stent-in-stent through a side hole to prevent biliary metallicstent migration.

    PubMed

    Ridtitid, Wiriyaporn; Rerknimitr, Rungsun; Amornsawadwattana, Surachai; Ponauthai, Yuwadee; Kullavanijaya, Pinit

    2011-03-16

    The covered self-expandable metallic stent (SEMS) has been developed to overcome the problem of tissue in-growth, However, stent migration is a well-known com--plication of covered SEMS placement. Use of a double pigtail stent to lock the movement of the SEMS and prevent migration has been advised by many ex-perts. Unfortunately, in our case this technique led to an in-cidental upward migration of the SEMS. We used APC to create a side hole in the SEMS for plastic stent insertion as stent-in-stent. This led to a successful pre-ven-tion of stent migration.

  14. Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention

    PubMed Central

    Kwon, Chang-Il; Lehman, Glen A.

    2016-01-01

    Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs]) have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations. PMID:27000422

  15. Ureteral Stents. New Materials and Designs

    NASA Astrophysics Data System (ADS)

    Monga, Manoj

    2008-09-01

    Issues of stent migration and challenges of stent placement can be addressed adequately with current stent designs and materials, and an emphasis on precision in technique. Future changes in ureteral stents will need to maintain the current standard that has been set with existing devices in these regards. In contrast, new advances are sorely needed in encrustation and infection associated with ureteral stents. The main target for future development in ureteral stent materials lies in a biodegradable stent that degrades either on demand or degrades reliably within one-month with predictable degradation patterns that do not predispose to urinary obstruction, discomfort or need for secondary procedures. The main target for future development in ureteral stent design is improved patient comfort.

  16. The Development of Carotid Stent Material

    PubMed Central

    He, Dongsheng; Liu, Wenhua; Zhang, Tao

    2015-01-01

    Endovascular angioplasty with stenting is a promising option for treating carotid artery stenosis. There exist a rapidly increasing number of different stent types with different materials. The bare-metal stent is the most commonly used stent with acceptable results, but it leaves us with the problems of thrombosis and restenosis. The drug-eluting stent is a breakthrough as it has the ability to reduce the restenosis rate, but the problem of late thrombosis still has to be addressed. The biodegradable stent disappears after having served its function. However, restenosis and degradation rates remain to be studied. In this article, we review every stent material with its characteristics, clinical results and complications and point out the standards of an ideal carotid stent. PMID:26019710

  17. Cocaine-induced very late stent thrombosis.

    PubMed

    Shah, Priyank; Vasudev, Rahul; Abuarqoub, Ahmad Hisham; Shamoon, Fayez

    2016-10-12

    Cocaine misuse is a known cause of acute coronary syndrome (ACS). Management of these patients has always been a challenge due to medication compliance and eventual risk of stent thrombosis. However, even cocaine misusers who are compliant with dual antiplatelet therapy have been reported to have stent thrombosis. All cases of cocaine-induced stent thrombosis reported in the literature have occurred within first year of stent placement (acute, subacute or late). We report a first case of very late stent thrombosis in a 54-year-old active cocaine misuser who presented with ST segment elevation myocardial infarction, which was successfully managed with percutaneous transluminal coronary angioplasty. A review of all the reported cases of cocaine-induced stent thrombosis is also discussed. Given the high mortality associated with stent thrombosis, treatment option for cocaine misusers presenting with ACS should be conservative when possible. If percutaneous coronary intervention is needed, bare metal stent should be preferred.

  18. Ureteric stents: investigating flow and encrustation.

    PubMed

    Waters, S L; Heaton, K; Siggers, J H; Bayston, R; Bishop, M; Cummings, L J; Grant, D M; Oliver, J M; Wattis, J A D

    2008-05-01

    Blockages of the ureter, e.g. due to calculi (kidney stones), can result in an increase in renal pelvic pressure. This may be relieved by inserting a stent (essentially a permeable hollow tube). However, a number of complications are associated with stent use. Stents can result in reflux (backflow of urine along the ureter), which will promote recurrent urinary infection and possible renal parenchymal damage. Furthermore, long-term stent use is associated with infection and precipitation of salts from the urine, which can lead to a build-up of crystalline deposits on the stent surface, making stent removal difficult and painful. This paper examines factors governing urine flow in a stented ureter, the implications for reflux, and the processes by which the stent surface encrusts, in particular focusing on the influence of bacterial infection. An interdisciplinary approach is adopted, involving a combination of theoretical investigations and novel experiments.

  19. Carotid Artery Stenting versus Endarterectomy

    PubMed Central

    Gahremanpour, Amir; Perin, Emerson C.; Silva, Guilherme

    2012-01-01

    For about 2 decades, investigators have been comparing carotid endarterectomy with carotid artery stenting in regard to their effectiveness and safety in treating carotid artery stenosis. We conducted a systematic review to summarize and appraise the available evidence provided by randomized trials, meta-analyses, and registries comparing the clinical outcomes of the 2 procedures. We searched the MEDLINE, SciVerse Scopus, and Cochrane databases and the bibliographies of pertinent textbooks and articles to identify these studies. The results of clinical trials and, consequently, the meta-analyses of those trials produced conflicting results regarding the comparative effectiveness and safety of carotid endarterectomy and carotid stenting. These conflicting results arose because of differences in patient population, trial design, outcome measures, and variability among centers in the endovascular devices used and in operator skills. Careful appraisal of the trials and meta-analyses, particularly the most recent and largest National Institutes of Healthsponsored trial (the Carotid Revascularization Endarterectomy vs Stenting Trial [CREST]), showed that carotid stenting and endarterectomy were associated with similar rates of death and disabling stroke. Within the 30-day periprocedural period, carotid stenting was associated with higher risks of stroke, especially for patients aged >70 years, whereas carotid endarterectomy was associated with a higher risk of myocardial infarction. The slightly higher cost of stenting compared with endarterectomy was within an acceptable range by cost-effectiveness standards. We conclude that carotid artery stenting is an equivalent alternative to carotid endarterectomy when patient age and anatomy, surgical risk, and operator experience are considered in the choice of treatment approach. PMID:22949763

  20. Late stent thrombosis after implantation of a sirolimus-eluting stent.

    PubMed

    Kerner, Arthur; Gruberg, Luis; Kapeliovich, Michael; Grenadier, Ehud

    2003-12-01

    Late stent thrombosis in the era of routine high-pressure stent deployment and combined antiplatelet therapy with thienopyridines and aspirin has become a rare but feared complication. We describe a patient with acute myocardial infarction due to late stent thrombosis 6 weeks after deployment of a sirolimus-eluting stent and 2 weeks after the discontinuation of clopidogrel. This is the first report of late thrombosis of a sirolimus-eluting stent.

  1. Impact of Stent Design on In-Stent Stenosis in a Rabbit Iliac Artery Model

    SciTech Connect

    Sommer, C. M. Grenacher, L.; Stampfl, U.; Arnegger, F. U.; Rehnitz, C.; Thierjung, H.; Stampfl, S.; Berger, I.; Richter, G. M.; Kauczor, H. U.; Radeleff, B. A.

    2010-06-15

    The purpose of this study was to evaluate the impact of stent design on in-stent stenosis in rabbit iliac arteries. Four different types of stent were implanted in rabbit iliac arteries, being different in stent design (crown or wave) and strut thickness (50 or 100 {mu}m). Ten stents of each type were implanted. Each animal received one crown and one wave stent with the same strut thickness. Follow-up was either 12 weeks (n = 10 rabbits) or 24 weeks (n = 10 rabbits). Primary study end points were angiographic and microscopic in-stent stenosis. Secondary study end points were vessel injury, vascular inflammation, and stent endothelialization. Average stent diameter, relative stent overdilation, average and minimal luminal diameter, and relative average and maximum luminal loss were not significantly different. However, a trend to higher relative stent overdilation was recognized in crown stents compared to wave stents. A trend toward higher average and minimal luminal diameter and lower relative average and maximum luminal loss was recognized in crown stents compared to wave stents with a strut thickness of 100 {mu}m. Neointimal height, relative luminal area stenosis, injury score, inflammation score, and endothelialization score were not significantly different. However, a trend toward higher neointimal height was recognized in crown stents compared to wave stents with a strut thickness of 50 {mu}m and a follow-up of 24 weeks. In conclusion, in this study, crown stents seem to trigger neointima. However, the optimized radial force might equalize the theoretically higher tendency for restenosis in crown stents. In this context, also more favorable positive remodeling in crown stents could be important.

  2. Fluid mechanics in stented arterial model

    NASA Astrophysics Data System (ADS)

    Bernad, S. I.; Totorean, A.; Bosioc, A.; Crainic, N.; Hudrea, C.; Bernad, E. S.

    2015-12-01

    Local hemodynamic factors are known affect the natural history of the restenosis critically after coronary stenting of atherosclerosis. Stent-induced flows disturbance magnitude dependent directly on the strut design. Strut shape, strut thickness and the distance between consecutive struts have been associated clinically with the with post-intervention clinical outcomes. Hemodynamically favorable designs according to computational modeling can reduced in-stent restenosis after coronary stenting intervention.

  3. Repositioning of Covered Stents: The Grip Technique

    SciTech Connect

    Kirby, John Martin; Guo Xiaofeng; Midia, Mehran

    2011-06-15

    Introduction: Retrieval and repositioning of a stent deployed beyond its intended target region may be a difficult technical challenge. Materials and Methods: A balloon-mounted snare technique, a variant of the coaxial loop snare technique, is described. Results: The technique is described for the repositioning of a covered transjugular intrahepatic portosystemic shunt stent and a covered biliary stent. Conclusion: The balloon-mounted snare technique is a useful technique for retrieval of migrated stents.

  4. Primary nitinol stenting for femoropopliteal disease.

    PubMed

    Mewissen, Mark W

    2009-04-01

    The 1- to 2-year primary patency rates associated with self-expanding nitinol stents for the treatment of symptomatic femoropopliteal disease are superior to those for percutaneous transluminal angioplasty (PTA) and the first-generation stainless steel balloon-expandable stents. The advantages of nitinol stents include improved radial strength and flexibility, the ability to recover from being crushed, reduced foreshortening, and (importantly) deployability without balloon dilation of the stent edge (which may decrease the incidence of the edge stenosis, or "candy-wrap" effect, often observed with balloon-expandable stents). The technical success rate associated with primary deployment of nitinol stents is very high, and acute to 6-month patency results are predictably excellent. Prior to the introduction of nitinol stents, the original guidelines (2000) of the multidisciplinary TransAtlantic Inter-Society Consensus (TASC I) recommended only an adjunctive role for femoropopliteal stents following suboptimal PTA. The abbreviated 2007 TASC II report essentially extended this recommendation to nitinol stents. Here, current trials of nitinol stenting in the femoropopliteal segment are discussed, with emphasis on the advantages of primary (and often direct) deployment in selected circumstances dependent on factors including lesion length, lesion location, indication for treatment (critical limb ischemia or claudication, in-stent restenosis, stent-graft restenosis), and the relative appropriateness of other modalities (e.g., covered stents). Technical considerations in primary nitinol stenting are briefly reviewed. Open questions regarding the factors involved in nitinol stent fracture and the possible association of fracture and restenosis are examined in the context of current clinical trials. A new generation of femoropopliteal nitinol stents combining superior durability and flexibility is expected soon. Development and implementation of uniform reporting and

  5. The need for stent-lesion matching to optimize outcomes of intracoronary stent implantation.

    PubMed

    Lanzer, Peter; Strupp, Gerhard; Schmidt, Wolfram; Topoleski, L D Timmie

    2013-11-01

    Intracoronary stents have markedly improved the outcomes of catheter-based coronary interventions. Intracoronary stent implantation rates of over 90% during coronary angioplasty are common. Stent implantations are associated with a small but statistically significant number of adverse outcomes including restenosis, thrombosis, strut malapposition, incomplete strut endothelialization, and various types of stenting failure. Better matching of biomechanical properties of stents and lesions could further improve the clinical outcome of intracoronary stenting. Thus, in this article, we assess the need for advanced intracoronary stent-lesion matching. We reviewed the data on biomechanics of coronary stents and lesions to develop knowledge-based rationale for optimum intracoronary stent selection. The available technical information on marketed intracoronary stents and the current understanding of the biomechanical properties of coronary lesions at rest and under stress are limited, preventing the development of knowledge-based rationale for optimum intracoronary stent selection at present. Development of knowledge-based selection of intracoronary stents requires standardization of mechanical stent testing, communication of the nonproprietary technical data on stents by the industry and dedicated research into procedural stent-lesion interactions.

  6. Refining stent technologies for femoral interventions.

    PubMed

    Bosiers, M; Deloose, K; Callaert, J; Maene, L; Keirse, K; Verbist, J; Peeters, P

    2012-08-01

    Stents were created as a mechanical scaffold to prevent vessel recoil and luminal renarrowing after percutaneous transluminal angioplasty (PTA). In femoropopliteal arteries, indication for stent implantation remains a topic much debated on, especially in long lesion configurations. Ever since the first stents were introduced on the market, in-stent restenosis (ISR) has been an important issue. The evolution in stent design has known a major progression in the last decades from the first generation of stents, plagued with high fracture rates and low primary patency rates, to the design of newer stents to tackle these outcomes. More flexible and longer stents decreased the high fracture rates and drug-eluting stents offered a solution to the restenosis rates by local drug application. The difficult recrossibility of the lesion because of the presence of a permanent vascular scaffold is an obstacle that the drug-coated balloon (DCB) overcomes. Future perspectives in the treatment of femoropopliteal lesions are found in the bioresorbable stent implantation. The bioresorbable stent combines the advantages of a drug-eluting scaffolding stent without the remainder of a foreign object in the long-term. Further investigations in this area will eventually evolve in the creation of a superior endovascular treatment modality with high long-term patency rates and minimal detriments.

  7. What to Expect After a Stent Procedure

    MedlinePlus

    ... time after the stent procedure. Your doctor will let you know when you can go back to your normal activities. Metal detectors used in airports and other screening areas don't affect stents. Your stent shouldn't cause metal ...

  8. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Prosthetic Devices § 884.3900 Vaginal stent. (a) Identification. A vaginal stent is a device used to enlarge the vagina by stretching, or...

  9. Migration of forgotten stent into renal pelvis

    PubMed Central

    Giridhar, Venkatesh; Natarajan, Kumaresan; Hegde, Padmaraj

    2011-01-01

    Stent migration is a well recognized complication of forgotten stents, but migration into the renal pelvis is rarely documented. We present a case of migration and coiling of a forgotten stent in the renal pelvis, and discuss briefly, the etiological factors for the phenomenon and associated problems in management. PMID:21814326

  10. Migration of forgotten stent into renal pelvis.

    PubMed

    Giridhar, Venkatesh; Natarajan, Kumaresan; Hegde, Padmaraj

    2011-04-01

    Stent migration is a well recognized complication of forgotten stents, but migration into the renal pelvis is rarely documented. We present a case of migration and coiling of a forgotten stent in the renal pelvis, and discuss briefly, the etiological factors for the phenomenon and associated problems in management.

  11. 21 CFR 876.4620 - Ureteral stent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ureteral stent. 876.4620 Section 876.4620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4620 Ureteral stent. (a) Identification. A ureteral stent...

  12. 21 CFR 876.4620 - Ureteral stent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ureteral stent. 876.4620 Section 876.4620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Surgical Devices § 876.4620 Ureteral stent. (a) Identification. A ureteral stent...

  13. Biodegradable stents: they do their job and disappear.

    PubMed

    Waksman, Ron

    2006-02-01

    Despite the development and progression of metallic stents, many concerns still remain because of their permanent nature. Although metallic stents are effective in preventing recoil and late restenosis after coronary angioplasty, they continue to have limitations such as stent thrombosis and mismatch of the stent to the vessel size. Thus, the concept of bioabsorbable stents has emerged as an alternative to permanent metal stents. This review will outline concepts, material designs, preclinical, and initial clinical experimental studies with bioabsorbable stents.

  14. Enhancing Stent Effectiveness with Nanofeatures

    PubMed Central

    Bassous, Nicole; Cooke, John P.; Webster, Thomas J.

    2016-01-01

    Drug-eluting stents are an effective therapy for symptomatic arterial obstructions, substantially reducing the incidence of restenosis by suppressing the migration and proliferation of vascular smooth muscle cells into the intima. However, current drug-eluting stents also inhibit the growth of endothelial cells, which are required to cover the vascular stent to reduce an excessive inflammatory response. As a result, the endothelial lining of the lumen is not regenerated. Since the loss of this homeostatic monolayer increases the risk of thrombosis, patients with drug-eluting stents require long-term antithrombotic therapy. Thus, there is a need for improved devices with enhanced effectiveness and physiological compatibility towards endothelial cells. Current developments in nanomaterials may enhance the function of commercially available vascular devices. In particular, modified design schemes might incorporate nanopatterns or nanoparticle-eluting features that reduce restenosis and enhance re-endothelialization. The intent of this review is to discuss emerging nanotechnologies that will improve the performance of vascular stents. PMID:27826371

  15. Foam-rubber stents for skin grafts.

    PubMed

    Larson, P O

    1990-09-01

    A variety of stents are used to immobilize skin grafts and to hold them firmly to the recipient site. Tie-down stents, the most common type, are constructed from bulky, sterile dressing and are overtied with suture material. These stents are often cumbersome to apply. As an alternative, stents made from foam-rubber pads (Reston, 3M Company, St. Paul, MN) were stapled over skin grafts. These stents could be applied quickly, and they maintain continuous, uniform pressure on the immobilized grafts.

  16. Low symptomatic premature stent occlusion of multiple plastic stents for benign biliary strictures: comparing standard and prolonged stent change intervals.

    PubMed

    Lawrence, Christopher; Romagnuolo, Joseph; Payne, K Mark; Hawes, Robert H; Cotton, Peter B

    2010-09-01

    Benign biliary strictures are typically managed endoscopically whereby an increasing size or number of plastic stents is placed at ERCP. Stents are often changed every 3 to 4 months based on the known median patency of a single biliary stent, but patency data for multiple biliary stents are lacking. To assess the incidence of occlusion-free survival of multiple plastic biliary stents and the rate of premature occlusion if left in longer than 6 months. Retrospective. Tertiary-care medical center (Charleston, SC). Consecutive patients who received multiple plastic stents for benign nonhilar biliary strictures from 1994 to 2008 were identified. Exchange of multiple plastic biliary stents within 6 months (group 1) or 6 months or longer (group 2) after placement. Symptomatic stent occlusion. Seventy-nine patients with nonhilar extrahepatic benign biliary stricture underwent 125 ERCPs with multiple plastic biliary stents. Stents were scheduled for removal/exchange within 6 months in 52 patients (86 ERCPs) compared with after 6 months in 22 patients (26 ERCPs). The median interval between multiple stent placement and removal/exchange was 90 days for group 1 and 242 days for group 2. Premature stent occlusion occurred in 4 of 52 (7.7%) patients in group 1 versus 1 of 22 (4.5%) in group 2, with significantly longer occlusion-free survival in group 2 (log-rank P < .0001). Retrospective study at a single tertiary referral center. Multiple plastic biliary stents for benign nonhilar strictures were associated with a low rate of premature symptomatic stent occlusion at more than 6 months and a longer occlusion-free survival. Copyright 2010 American Society for Gastrointestinal Endoscopy. Published by Mosby, Inc. All rights reserved.

  17. Advances in stent drug delivery: the future is in bioabsorbable stents.

    PubMed

    Wykrzykowska, Joanna J; Onuma, Yoshinobu; Serruys, Patrick W

    2009-02-01

    This expert opinion review offers a perspective on the future developments in drug-eluting stent design. Initial efforts were focused on reduction of in-stent restenosis, which the drug-eluting stents addressed effectively. Current concerns are predominantly with regard to risk of stent thrombosis and delayed endothelialization. All three components of the stent have been modified to achieve the goal of endothelialization and vessel healing: drug, polymer and the platform. We review different approaches to reduce this risk from design of different drug combinations, through less traumatic metallic stent platforms, via biodegradable polymers and, finally, fully biodegradable stents. It seems at this time that fully biodegradable solutions to stenting hold the greatest promise, but larger long-term studies are needed to evaluate fully their safety and efficacy in 'all-comer' patient populations. At the time of this review, design of a safe drug-eluting stent still remains a challenge.

  18. Primary and revision efficacy of cross-wired metallic stents for endoscopic bilateral stent-in-stent placement in malignant hilar biliary strictures.

    PubMed

    Lee, T H; Moon, J H; Kim, J H; Park, D H; Lee, S S; Choi, H J; Cho, Y D; Park, S H; Kim, S J

    2013-01-01

    Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision. A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy. The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2% (80/84) and 92.9% (78/84), respectively. Median patency (range) and survival were 238 days (10-429) and 256 days (10-1130), respectively. Obstruction of primary bilateral stents occurred in 30.8% (24/78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3% (20/24) and 79.2% (19/24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0%); the remaining patients received plastic stents. Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded. © Georg Thieme Verlag KG Stuttgart · New York.

  19. [Absorbable coronary stents. New promising technology].

    PubMed

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

    2007-06-01

    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  20. Risks of noncardiac surgery after coronary stenting.

    PubMed

    Reddy, Proddutur R; Vaitkus, Paul T

    2005-03-15

    An increased risk of major complications for noncardiac surgery after coronary stenting has been suggested. We retrospectively reviewed all cases of coronary stents from 1999 to 2003 with subsequent surgery to assess major adverse cardiovascular events (MACEs), including myocardial infarction, stent thrombosis, major bleeding, and death. Among the 56 patients identified, 8 developed MACEs; 38% underwent surgery < or =14 days after stenting, and 62% underwent surgery 15 to 42 days after stenting. No patient developed MACEs if surgery occurred >42 days after stenting. Among patients who developed MACEs, 77% of surgeries were elective, 19% were urgent, and only 4% were emergency. Noncardiac surgery 6 weeks after coronary stenting is associated with a high risk of MACEs.

  1. Current Status of Biliary Metal Stents

    PubMed Central

    Nam, Hyeong Seok; Kang, Dae Hwan

    2016-01-01

    Many advances have been achieved in biliary stenting over the past 30 years. Endoscopic stent placement has become the primary management therapy to relieve obstruction in patients with benign or malignant biliary tract diseases. Compared with plastic stents, a self-expandable metallic stent (SEMS) has been used for management in patients with malignant strictures because of a larger lumen and longer stent patency. Recently, SEMS has been used for various benign biliary strictures and leaks. In this article, we briefly review the characteristics of SEMS as well as complications of stent placement. We review the current guidelines for managing malignant and benign biliary obstructions. Recent developments in biliary stenting are also discussed. PMID:26911896

  2. Treatment of central venous in-stent restenosis with repeat stent deployment in hemodialysis patients.

    PubMed

    Ronald, James; Davis, Bradley; Guevara, Carlos J; Pabon-Ramos, Waleska M; Smith, Tony P; Kim, Charles Y

    2017-05-15

    To report patency rates for stent deployment for treatment of in-stent stenosis of the central veins of the chest in hemodialysis patients. A retrospective analysis was performed on 29 patients who underwent 35 secondary percutaneous transluminal stent (PTS) deployments for in-stent stenosis within the central veins that were refractory to angioplasty and ipsilateral to a functioning hemodialysis access (in-stent PTS group). For comparison, patency data were acquired for 47 patients who underwent 78 successful percutaneous transluminal angioplasty (PTA) procedures for in-stent stenosis (in-stent PTA group) and 55 patients who underwent 55 stent deployments within native central vein stenosis refractory to angioplasty (native vein PTS group). The 3-, 6-, and 12-month primary lesion patency for the in-stent PTS group was 73%, 57%, and 32%, respectively. The 3-, 6-, and 12-month primary patency for the in-stent PTA group was 70%, 38%, and 17% and for the native vein PTS group was 78%, 57%, and 26%, which were similar to the in-stent PTS group (p = 0.20 and 0.41, respectively). The 3-, 6-, and 12-month secondary access patency was 91%, 73%, and 65% for the in-stent PTS group. Sub-analysis of the in-stent PTS group revealed no difference in primary (p = 0.93) or secondary patency rates (p = 0.27) of bare metal stents (n = 23) compared with stent grafts (n = 12). Stent deployment for central vein in-stent stenosis refractory to angioplasty was associated with reasonable patency rates, which were similar to in-stent PTA and native vein PTS.

  3. A comparative evaluation of early stent occlusion among biliary conventional versus wing stents.

    PubMed

    Khashab, Mouen A; Hutfless, Susan; Kim, Katherine; Lennon, Anne Marie; Canto, Marcia I; Jagannath, Sanjay B; Okolo, Patrick I; Shin, Eun Ji; Singh, Vikesh K

    2012-06-01

    Conventional plastic stents with a lumen typically have limited patency. The lumenless wing stent was engineered to overcome this problem. The objective of this study was to compare the incidence of early stent occlusion (symptomatic occlusion/cholangitis necessitating re-insertion within 90 days) for wing stents and conventional plastic stents. Patients with biliary pathology treated with plastic biliary stenting during the period 2003-2009 comprised the study cohort. Patients who had at least one biliary wing stent placed comprised the wing stent group, whereas patients who underwent only conventional stent plastic placement comprised the conventional stent group. Patients were stratified by indication: benign biliary strictures (group 1), malignant biliary strictures (group 2), or benign biliary non-stricture pathology (group 3). The association of stent type with the occurrence of primary outcome by indication was analyzed by use of multivariable logistic regression. Three-hundred and forty-six patients underwent 612 ERCP procedures with placement of plastic biliary stent(s). On multivariate analysis, early stent occlusion did not differ between the wing and conventional groups in groups 1, 2, and 3. Among patients who achieved primary outcome in group 2, significantly fewer patients in the wing group had cholangitis (6.7% vs. 39.1%, P = 0.03). Among patients who achieved primary outcome in group 3, significantly fewer patients in the wing group had cholangitis (10% vs. 50%, P = 0.03). Early stent occlusion was similar for wing stents and conventional plastic stents. Wing stents, however, were associated with a lower incidence of cholangitis in patients with malignant biliary obstruction and benign non-stricturing biliary pathology.

  4. Ureteral Stent Coatings: What's Here and What's Coming

    NASA Astrophysics Data System (ADS)

    Razvi, Hassan

    2008-09-01

    Ureteral stents have become an indispensable tool to the urologist in the management of various disorders afflicting the urinary tract. While the ideal stent remains elusive, novel technical advances in stent coating technology offer the potential of enhancing stent biocompatibility and clinical application. Currently available stent coatings as well as new and emerging devices will be reviewed.

  5. Management of iatrogenic porto-biliary fistula following biliary stent.

    PubMed

    Chaitowitz, I M; Heng, R; Bell, K W

    2007-12-01

    We describe a case of cystic pancreatic disease causing biliary obstruction requiring percutaneous biliary stenting. The patient subsequently re-presented with severe melaena shown to be due to a rare complication of biliary stenting with development of a porto-biliary fistula from stent erosion, successfully managed with a 'stent-within-stent'.

  6. Stenting for restenotic lesions with the BARD XT stent.

    PubMed

    Rahel, Braim M; Suttorp, Maarten J; Te Riele, Hans A; Bal, Egbert T; Ernst, Sjef M; Mast, E Gijs; Ten Berg, Jurriën M; Kelder, Johannes C; Plokker, H W Thijs

    2003-06-01

    Conventional PTCA for the treatment of restenotic lesions is associated with a high rate of recurrence (30-50%). Primary stenting decreases the restenosis rate at long-term follow-up. One-hundred consecutive patients with restenosis received a Bard XT stent. Follow-up angiography was performed after 6 months. Angiograms were compared by means of computed quantitative analysis. The mean pretreatment reference diameter was 2.88 +/- 0.51 mm. The mean minimal luminal diameter (MLD) increased from 1.09 +/- 0.57 mm to 2.70 +/- 0.44 mm. The percent diameter stenosis decreased from 66 +/- 13% to 15 +/- 10%. The procedural success rate was 99%. At 6 month follow-up repeat angiography was performed in 86 patients. The mean MLD was 1.74 +/- 0.67 mm with a mean diameter stenosis of 41 +/- 20%. Residual anginal complaints were reported in 29% of patients. In-stent restenosis (defined as diameter stenosis of more than 50%) occurred in 18% of the patients. Placement of the Bard XT stent in restenotic lesions is feasible, has an excellent short term outcome and yields a favorable result at 6 month follow-up angiography.

  7. Forgotten ureteral stents: who's at risk?

    PubMed

    Divakaruni, Naveen; Palmer, Cristina J; Tek, Peter; Bjurlin, Marc A; Gage, Mistry K; Robinson, Jed; Lombardo, Lindsay; Wille, Mark A; Hollowell, Courtney M P

    2013-08-01

    The sequelae from forgotten stents carry significant morbidity and costs. In this study, we attempt to identify potential risk factors that may make patients less likely to follow up for stent removal so that more effective prevention efforts may be directed at these persons. A single-institution retrospective analysis of 187 consecutive patients who had stents placed between January 2010 and December 2010 was performed. Chart review was conducted to see if patients had undergone stent removal beyond the intended maximal stent life (MSL). Patients who were lost to follow-up were contacted to determine if stents were overdue. Logistic regression was performed to determine risk factors. Of the 187 patients who had stents placed, 147 had the stent removed before MSL and 28 had stents removed after the MSL. Twelve patients could not be contacted and were excluded from the analysis. Within our cohort of 175 patients, 48% were males, 73% were minorities (33% Latino, 30% Black, 8% Asian, and 2% Native American), 39% did not speak English, 79% were unemployed, 73% were uninsured, and 35% were married. Among the patients with forgotten stents, 68% were male, 64% were minorities (32% Latino, 29% Black, 4% Native American, and 0% Asian), 82% were unemployed, 39% did not speak English, 93% were uninsured, and 43% were married. Multivariate regression analysis demonstrated that uninsured patients (odds ratio [OR], 6.3; 95% confidence interval [CI], 1.4-28.2; P value 0.01) and males (OR, 2.8; CI, 1.2-6.8; P=0.02) had statistically significant associations with forgotten stents. Men were 2.8 times more likely to have forgotten stents than females. Patients without health insurance were six times more likely to have forgotten stents than patients with insurance. As efforts are made to prevent forgotten stents, increased attention should be given to these higher-risk patient populations.

  8. Drug eluting biliary stents to decrease stent failure rates: A review of the literature

    PubMed Central

    Shatzel, Joseph; Kim, Jisoo; Sampath, Kartik; Syed, Sharjeel; Saad, Jennifer; Hussain, Zilla H; Mody, Kabir; Pipas, J Marc; Gordon, Stuart; Gardner, Timothy; Rothstein, Richard I

    2016-01-01

    Biliary stenting is clinically effective in relieving both malignant and non-malignant obstructions. However, there are high failure rates associated with tumor ingrowth and epithelial overgrowth as well as internally from biofilm development and subsequent clogging. Within the last decade, the use of prophylactic drug eluting stents as a means to reduce stent failure has been investigated. In this review we provide an overview of the current research on drug eluting biliary stents. While there is limited human trial data regarding the clinical benefit of drug eluting biliary stents in preventing stent obstruction, recent research suggests promise regarding their safety and potential efficacy. PMID:26839648

  9. An in Vitro Twist Fatigue Test of Fabric Stent-Grafts Supported by Z-Stents vs. Ringed Stents

    PubMed Central

    Lin, Jing; Guidoin, Robert; Du, Jia; Wang, Lu; Douglas, Graeham; Zhu, Danjie; Nutley, Mark; Perron, Lygia; Zhang, Ze; Douville, Yvan

    2016-01-01

    Whereas buckling can cause type III endoleaks, long-term twisting of a stent-graft was investigated here as a mechanism leading to type V endoleak or endotension. Two experimental device designs supported with Z-stents having strut angles of 35° or 45° were compared to a ringed control under accelerated twisting. Damage to each device was assessed and compared after different durations of twisting, with focus on damage that may allow leakage. Stent-grafts with 35° Z-stents had the most severe distortion and damage to the graft fabric. The 45° Z-stents caused less fabric damage. However, consistent stretching was still seen around the holes for sutures, which attach the stents to the graft fabric. Larger holes may become channels for fluid percolation through the wall. The ringed stent-graft had the least damage observed. Stent apexes with sharp angles appear to be responsible for major damage to the fabrics. Device manufacturers should consider stent apex angle when designing stent-grafts, and ensure their devices are resistant to twisting. PMID:28787913

  10. An in Vitro Twist Fatigue Test of Fabric Stent-Grafts Supported by Z-Stents vs. Ringed Stents.

    PubMed

    Lin, Jing; Guidoin, Robert; Du, Jia; Wang, Lu; Douglas, Graeham; Zhu, Danjie; Nutley, Mark; Perron, Lygia; Zhang, Ze; Douville, Yvan

    2016-02-16

    Whereas buckling can cause type III endoleaks, long-term twisting of a stent-graft was investigated here as a mechanism leading to type V endoleak or endotension. Two experimental device designs supported with Z-stents having strut angles of 35° or 45° were compared to a ringed control under accelerated twisting. Damage to each device was assessed and compared after different durations of twisting, with focus on damage that may allow leakage. Stent-grafts with 35° Z-stents had the most severe distortion and damage to the graft fabric. The 45° Z-stents caused less fabric damage. However, consistent stretching was still seen around the holes for sutures, which attach the stents to the graft fabric. Larger holes may become channels for fluid percolation through the wall. The ringed stent-graft had the least damage observed. Stent apexes with sharp angles appear to be responsible for major damage to the fabrics. Device manufacturers should consider stent apex angle when designing stent-grafts, and ensure their devices are resistant to twisting.

  11. Comparison of a New Polytetrafluoroethylene-Covered Metallic Stent to a Noncovered Stent in Canine Ureters

    SciTech Connect

    Chung, Hwan-Hoon Lee, Seung Hwa; Cho, Sung Bum; Park, Hong Suk; Kim, Young Sik; Kang, Byung Chul; Frisoli, Joan K.; Razavi, Mahmood K.

    2008-05-15

    The aim of this study was to determine the feasibility of using a newly designed polytetrafluoroethylene (PTFE)-covered metallic stent in the ureter by comparing its effectiveness with that of the noncovered stent in a canine model. We placed 14 stents in the ureters of seven mongrel dogs that weighed 30-40 kg each. The covered and noncovered stents were deployed in the right and left ureters, respectively, of six dogs. In the seventh dog, a covered stent and a double-J catheter were inserted in the right ureter, and a covered stent only was inserted in the left ureter. The first six dogs were sacrificed at 5, 10, and 15 weeks after deployment of the stents (two for each follow-up period), and the seventh dog was sacrificed at 30 weeks. There was no migration or poor expansion of any of the stents observed on plain radiography. On intravenous pyelogram and retrograde pyelogram, all of the covered stents at each follow-up period had patent lumens at the stented segments without hydronephrosis, and the passage of contrast material through it was well preserved. The noncovered stents in the dogs sacrificed at 5 and 10 weeks and one of the two dogs sacrificed at 15 weeks showed near-complete occlusion of the stent lumen due to ingrowth of the soft tissue, and severe hydronephrosis was also noted. The noncovered stent in the other dog sacrificed at 15 weeks showed the passage of contrast material without hydronephrosis, but the lumen of the stent was still nearly occluded by the soft tissue. There was no evidence of hydronephrosis or passage disturbance of the contrast material in both ureters of the dog sacrificed at 30 weeks. We conclude that the newly designed PTFE-covered stent effectively prevented the luminal occlusion caused by urothelial hyperplasia compared to the near-total occlusion of the noncovered stents, and no migration of the covered stents was noted.

  12. MR Angiography of Peripheral Arterial Stents: In Vitro Evaluation of 22 Different Stent Types

    PubMed Central

    Burg, Matthias C.; Bunck, Alexander C.; Seifarth, Harald; Buerke, Boris; Kugel, Harald; Hesselmann, Volker; Köhler, Michael; Heindel, Walter; Maintz, David

    2011-01-01

    Purpose. To evaluate stent lumen visibility of a large sample of different peripheral arterial (iliac, renal, carotid) stents using magnetic resonance angiography in vitro. Materials and Methods. 21 different stents and one stentgraft (10 nitinol, 7 316L, 2 tantalum, 1 cobalt superalloy, 1 PET + cobalt superalloy, and 1 platinum alloy) were examined in a vessel phantom (vessel diameters ranging from 5 to 13 mm) filled with a solution of Gd-DTPA. Stents were imaged at 1.5 Tesla using a T1-weighted 3D spoiled gradient-echo sequence. Image analysis was performed measuring three categories: Signal intensity in the stent lumen, lumen visibility of the stented lumen, and homogeneity of the stented lumen. The results were classified using a 3-point scale (good, intermediate, and poor results). Results. 7 stents showed good MR lumen visibility (4x nitinol, 2x tantalum, and 1x cobalt superalloy). 9 stents showed intermediate results (5x nitinol, 2x 316L, 1x PET + cobalt superalloy, and 1x platinum alloy) and 6 stents showed poor results (1x nitinol, and 5x 316L). Conclusion. Stent lumen visibility varies depending on the stent material and type. Some products show good lumen visibility which may allow the detection of stenoses inside the lumen, while other products cause artifacts which prevent reliable evaluation of the stent lumen with this technique. PMID:22091380

  13. Self-expanding metal stents in malignant esophageal obstruction: a comparison between two stent types.

    PubMed

    Schmassmann, A; Meyenberger, C; Knuchel, J; Binek, J; Lammer, F; Kleiner, B; Hürlimann, S; Inauen, W; Hammer, B; Scheurer, U; Halter, F

    1997-03-01

    Self-expanding metal stents are a promising alternative in the palliation of malignant esophageal obstruction, but the relative value of different stent types is not well established. During a 3-year enrollment period in four different centers, 82 consecutive patients with malignant dysphagia without tumor recurrence after surgery or esophagorespiratory fistulas received either an uncovered Wallstent (44 patients) or a knitted nitinol stent (38 patients). Age (median: 79 yr), sex (F:M = 33:67), dysphagia score (median: 3), Karnofsky score (median: 53), body mass index (median: 19), type of pretreatment, tumor stage, stricture length (median: 5.4 cm), and stricture location were comparable in both stent groups. After stent placement, median dysphagia score improved markedly in both groups by two points. Procedure-related mortality (16 vs 0%; p < 0.01), early complication rate (32 vs 8%; p < 0.01), and severe persistent pain after stent placement (23 vs 0%; p < 0.002) were higher in the Wallstent compared with the knitted nitinol stent group. In contrast, stent dysfunction (7 vs 32%; p < 0.005), reintervention rate (9 vs 34%; p < 0.005), and costs were lower in the Wallstent compared with the nitinol stent group. In malignant esophageal obstruction, both stents markedly improved dysphagia. Uncovered Wallstents seem to cause more early severe complications than knitted nitinol stents. In contrast, stent dysfunction, reintervention rate, and costs appear to be higher in the nitinol stent group.

  14. A new SWL titanium stent (Zebra Stent): resistance to shockwave exposure.

    PubMed

    Buchholz, Noor N P; Cannaby, Clive; Fong, Ruby; Gray, Andrew; Andrews, Henry O; Birch, Malcolm J

    2005-06-01

    Recently, a new-concept lumen-less Teflon-coated double-J wire stent (Zebra stent) has been introduced to facilitate residual stone clearance, in particular after SWL. Its metal core expresses highly mismatched acoustic impedance. It was the aim of this study to exclude damage to the stent through shockwaves. Also, its Teflon coating should to some degree prevent encrustation, and stents removed from stone formers were examined for encrustation. Series of 2000 shockwaves of an average and a maximum energy were applied to defined areas of Zebra stents in a waterbath on a Siemens Multiline Lithotriptor. Stents were then examined for core and sheath damage by digital photography, scanning electron microscopy, and microradiography. In addition, two Zebra stents and one conventional double-J stent from two stone formers were assessed in the same way for damage and encrustation. There was no damage whatsoever to either of the stents. Whereas there was considerable encrustation on the conventional double-J stent, there was none on the Zebra stents after 4 and 5 weeks in situ. Zebra stents resist shockwaves to a maximum number and energy sufficiently to be applied safely under SWL. Whether they resist encrustation to a higher degree in the short term than conventional stents remains to be established.

  15. Impact of bifurcation dual stenting on endothelial shear stress

    PubMed Central

    Chen, Henry Y.; Koo, Bon-Kwon

    2015-01-01

    Despite advances in percutaneous coronary interventions and the introduction of drug eluding stents, in-stent restenosis and stent thrombosis remain a clinically significant problem for bifurcations. The aim of this study is to determine the effect of dual bifurcation stenting on hemodynamic parameters known to influence restenosis and thrombosis. We hypothesized that double stenting, especially with a longer side branch (SB) stent, likely has a negative effect on wall shear stress (WSS), WSS gradient (WSSG), and oscillatory shear index (OSI). To test this hypothesis, we developed computational models of dual stents at bifurcations and non-Newtonian blood simulations. The models were then interfaced, meshed, and solved in a validated finite-element package. Longer and shorter stents at the SB and provisional stenting were compared. It was found that stents placed in the SB at a bifurcation lowered WSS, but elevated WSSG and OSI. Dual stenting with longer SB stent had the most adverse impact on SB endothelial WSS, WSSG, and OSI, with low WSS region up to 50% more than the case with shorter SB stent. The simulations also demonstrated flow disturbances resulting from SB stent struts protruding into the main flow field near the carina, which may have implications on stent thrombosis. The simulations predict a negative hemodynamic role for SB stenting, which is exaggerated with a longer stent, consistent with clinical trial findings that dual-stenting is comparable or inferior to provisional stenting. PMID:26183473

  16. Endoscopic stenting for laparoscopic sleeve gastrectomy leaks

    PubMed Central

    Aydın, Mehmet Timuçin; Alahdab, Yeşim Özen; Aras, Orhan; Karip, Bora; Onur, Ender; İşcan, Yalın; Memişoğlu, Kemal

    2016-01-01

    Objective Laparoscopic sleeve gastrectomy is a widely accepted and effective bariatric surgery method. The rate of leakage at the staple-line has been reported to be between 1.5 and 5%. Aside from the use of percutaneous drainage, re-laparoscopy, or abdominal sepsis control by laparotomy, endoscopic esophagogastric stent placement is increasingly preferred as a treatment method. Because laparoscopic sleeve gastrectomy is a widely used modality in our hospital, we aimed to evaluate the rate of leaks and the results of stent placements in our patients. Material and Methods Between January 1st 2010 and August 31st 2014, laparoscopic sleeve gastrectomy was performed on 236 patients by three surgeons. The demographic information and postoperative discharge summaries were collected and analyzed with the permission of the hospital ethics committee. Information about leak treatment management was also collected. Results Leaks after laparoscopic sleeve gastrectomy in four patients were stented in the first postoperative month. Short (12 cm) Hanora® (M.I.Tech, Gyeonggi-do, Korea) self-expandable coated stents were placed in two patients, and long (24 cm) Hanora® self-expandable coated stents were placed in the other two. The stents were removed after one month in two patients, two and a half months later in one, and five months later in another patient. The leaks were demonstrated to be healed in all patients after stent removal. Endoscopic stent revision was performed in one patient due to migration of the stent and in another for stent breakage. Conclusion The success rate of treatment of leaks after laparoscopic sleeve gastrectomy by stent placement has been variable in the literature. The success in early stent placement has been shown to be related to physician expertise. According to the results of our patients, we suggest that endoscopic stent placement in the early stage after controlling sepsis is an effective method in the management of leaks. PMID:28149125

  17. Distal 'buddy-in-jail' technique: a complementary 'Jail with stent' method for stent delivery.

    PubMed

    Dangoisse, Vincent; Guédès, Antoine; Schroëder, Erwin

    2014-03-01

    Delivery of coronary stents can be challenging, but the use of a second or 'buddy' wire helps the progression of equipment through tortuous and rigid vessels. We successfully positioned a coronary stent in a distal lesion, intentionally jailing the buddy wire during stent delivery. The jailed wire was then used to proceed further with proximal coronary stenting. We report 10 cases using either the jailed or the non-jailed wire for this modified 'buddy-in-jail' technique.

  18. Therapeutic efficacy and stent patency of transhepatic portal vein stenting after surgery

    PubMed Central

    Jeon, Ung Bae; Kim, Chang Won; Kim, Tae Un; Choo, Ki Seok; Jang, Joo Yeon; Nam, Kyung Jin; Chu, Chong Woo; Ryu, Je Ho

    2016-01-01

    AIM To evaluate portal vein (PV) stenosis and stent patency after hepatobiliary and pancreatic surgery, using abdominal computed tomography (CT). METHODS Percutaneous portal venous stenting was attempted in 22 patients with significant PV stenosis (> 50%) - after hepatobiliary or pancreatic surgery - diagnosed by abdominal CT. Stents were placed in various stenotic lesions after percutaneous transhepatic portography. Pressure gradient across the stenotic segment was measured in 14 patients. Stents were placed when the pressure gradient across the stenotic segment was > 5 mmHg or PV stenosis was > 50%, as observed on transhepatic portography. Patients underwent follow-up abdominal CT and technical and clinical success, complications, and stent patency were evaluated. RESULTS Stent placement was successful in 21 patients (technical success rate: 95.5%). Stents were positioned through the main PV and superior mesenteric vein (n = 13), main PV (n = 2), right and main PV (n = 1), left and main PV (n = 4), or main PV and splenic vein (n = 1). Patients showed no complications after stent placement. The time between procedure and final follow-up CT was 41-761 d (mean: 374.5 d). Twenty stents remained patent during the entire follow-up. Stent obstruction - caused by invasion of the PV stent by a recurrent tumor - was observed in 1 patient in a follow-up CT performed after 155 d after the procedure. The cumulative stent patency rate was 95.7%. Small in-stent low-density areas were found in 11 (55%) patients; however, during successive follow-up CT, the extent of these areas had decreased. CONCLUSION Percutaneous transhepatic stent placement can be safe and effective in cases of PV stenosis after hepatobiliary and pancreatic surgery. Stents show excellent patency in follow-up abdominal CT, despite development of small in-stent low-density areas. PMID:27956806

  19. Safety, efficacy and costs associated with direct coronary stenting compared with stenting after predilatation

    PubMed Central

    IJsselmuiden, A.; Serruys, P.W.; Tangelder, G.J.; Slagboom, T.; van der Wieken, R.; Kiemeneij, F.; Laarman, G.J.

    2004-01-01

    Objectives Comparison of the in-hospital success rates, procedural costs and short-term clinical outcomes of direct stenting versus stenting after balloon predilatation. Methods Altogether, 400 patients with angina pectoris and/or myocardial ischaemia due to coronary stenoses in a single native vessel were randomised to either direct stenting or stenting after predilatation. Baseline characteristics were evenly distributed between the two groups. Results Procedural success rates were similar (96.0% direct stenting group vs. 94.5% predilatation) as well as final successful stent implantation (98.3 vs. 97.8%), while the primary success rate of direct stenting alone was 88.3%, p=0.01. In multivariate analysis, angiographic lesion calcification was an independent predictor of unsuccessful direct stenting (odds ratio 7.1, 95% confidence interval 2.8-18.2, p<0.0001). Rates of troponin I rises >0.15 μg/l, used as a measure of distal embolisation, were similar in both groups (17.8 vs. 17.1%). Rates of major adverse cardiac events at 30 days were 4.5% in the direct stenting group versus 5.5% in the predilated group (ns). Direct stenting was associated with savings in fluoroscopy time, and angiographic contrast agent use, and a reduction in utilisation of angioplasty balloons (0.4 vs. 1.17 balloons per patient, p<0.001). Mean per patient procedural costs associated with direct stenting versus predilatation were €2545±914 versus €2763±842 (p=0.01), despite the implantation of more stents in the directly stented group. Conclusion Compared with a strategy of stenting preceded by balloon predilatation, direct stenting was equally safe and effective, with similar in-hospital and 30-day clinical outcomes, and modest procedural cost-savings. A calcified lesion predicted unsuccessful direct stenting. PMID:25696356

  20. Review of stents for the carotid artery.

    PubMed

    Bosiers, M; Deloose, K; Verbist, J; Peeters, P

    2006-04-01

    The individual characteristics of a stent may make it an attractive choice in some circumstances, but render it a less desirable option in others. The applicability depends primarily on the arterial anatomy and the specific details of the lesion being treated. A careful assessment by the interventionalist is required to select the proper type of stent that is of appropriate size. Certainly, personal preferences and familiarity with a specific device may legitimately influence the decision to choose one stent over another. Finally, stent design can play a role in the selection procedure. Although carotid stents are often functionally equivalent in the clinical setting and have been used successfully to treat a wide variety of lesions, a basic knowledge of stent geometry can contribute to make up your mind in certain carotid cases.

  1. Prevention of stent thrombosis: challenges and solutions

    PubMed Central

    Reejhsinghani, Risheen; Lotfi, Amir S

    2015-01-01

    Stent thrombosis is an uncommon but serious complication which carries with it significant mortality and morbidity. This review analyzes the entity of stent thrombosis from a historical and clinical perspective, and chronicles the evolution of this condition through the various generations of stent development, from bare metal to first-generation, second-generation, and third-generation drug-eluting stents. It also delineates the specific risk factors associated with stent thrombosis and comprehensively examines the literature related to each of these risks. Finally, it highlights the preventative strategies that can be garnered from the existing data, and concludes that a multifactorial approach is necessary to combat the occurrence of stent thrombosis, with higher risk groups, such as patients with ST segment elevation myocardial infarction, meriting further research. PMID:25657588

  2. Bioabsorbable stenting in peripheral artery disease.

    PubMed

    Galyfos, George; Geropapas, Georgios; Stefanidis, Ioannis; Kerasidis, Stavros; Stamatatos, Ioannis; Kastrisios, Georgios; Giannakakis, Sotirios; Papacharalampous, Gerasimos; Maltezos, Chrisostomos

    2015-12-01

    Arterial stenting has been broadly utilized for the management of peripheral arterial occlusive disease. The evolution of stent materials has led to the introduction of newer bioabsorbable scaffolds that have been extensively evaluated in the treatment of coronary artery disease. However, the utilization of bioabsorbable stents in the lower extremities remains challenging and has not been evaluated in the same degree. There are not many trials focusing on major outcomes of treatment with bioabsorbable stents or comparing them with other therapeutic choices such as surgery or angioplasty only. The aim of this review is to report current status on bioabsorbable stenting in peripheral artery disease treatment as well as to present the results of all major relevant trials. Moreover, future expectations and challenges with this type of stents are discussed as well. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Rapid Virtual Stenting for Intracranial Aneurysms

    PubMed Central

    Zhao, Liang; Chen, Danyang; Chen, Zihe; Wang, Xiangyu; Paliwal, Nikhil; Xiang, Jianping; Meng, Hui; Corso, Jason J.; Xu, Jinhui

    2016-01-01

    The rupture of Intracranial Aneurysms is the most severe form of stroke with high rates of mortality and disability. One of its primary treatments is to use stent or Flow Diverter to divert the blood flow away from the IA in a minimal invasive manner. To optimize such treatments, it is desirable to provide an automatic tool for virtual stenting before its actual implantation. In this paper, we propose a novel method, called ball-sweeping, for rapid virtual stenting. Our method sweeps a maximum inscribed sphere through the aneurysmal region of the vessel and directly generates a stent surface touching the vessel wall without needing to iteratively grow a deformable stent surface. Our resulting stent mesh has guaranteed smoothness and variable pore density to achieve an enhanced occlusion performance. Comparing to existing methods, our technique is computationally much more efficient. PMID:27346910

  4. Rapid virtual stenting for intracranial aneurysms

    NASA Astrophysics Data System (ADS)

    Zhao, Liang; Chen, Danyang; Chen, Zihe; Wang, Xiangyu; Paliwal, Nikhil; Xiang, Jianping; Meng, Hui; Corso, Jason J.; Xu, Jinhui

    2016-03-01

    The rupture of Intracranial Aneurysms is the most severe form of stroke with high rates of mortality and disability. One of its primary treatments is to use stent or Flow Diverter to divert the blood flow away from the IA in a minimal invasive manner. To optimize such treatments, it is desirable to provide an automatic tool for virtual stenting before its actual implantation. In this paper, we propose a novel method, called ball-sweeping, for rapid virtual stenting. Our method sweeps a maximum inscribed sphere through the aneurysmal region of the vessel and directly generates a stent surface touching the vessel wall without needing to iteratively grow a deformable stent surface. Our resulting stent mesh has guaranteed smoothness and variable pore density to achieve an enhanced occlusion performance. Comparing to existing methods, our technique is computationally much more efficient.

  5. Acute Duodenal Obstruction After Percutaneous Placement of Metallic Biliary Stents: Peroral Treatment with Enteral Stents

    SciTech Connect

    Lopera, Jorge E. Alvarez, Oscar A.; Perdigao, Joseph; Castaneda-Zuniga, Wilfrido

    2003-09-15

    Three patients with malignant biliary obstruction were treated with placement of metallic biliary stents. Two patients had known partial duodenal stenosis but had no symptoms of gastrointestinal obstruction. The patients developed symptomatic duodenal obstruction early after biliary metallic stent placement. The symptomatic duodenal obstructions were successfully treated with peroral placement of duodenal stents, which obviated the need for surgical intervention.

  6. Mechanical behavior of peripheral stents and stent-vessel interaction: A computational study

    NASA Astrophysics Data System (ADS)

    Dottori, Serena; Flamini, Vittoria; Vairo, Giuseppe

    2016-05-01

    In this paper stents employed to treat peripheral artery disease are analyzed through a three-dimensional finite-element approach, based on a large-strain and large-displacement formulation. Aiming to evaluate the influence of some stent design parameters on stent mechanics and on the biomechanical interaction between stent and arterial wall, quasi-static and dynamic numerical analyses are carried out by referring to computational models of commercially and noncommercially available versions of both braided self-expandable stents and balloon-expandable stents. Addressing isolated device models, opening mechanisms and flexibility of both opened and closed stent configurations are numerically experienced. Moreover, stent deployment into a stenotic peripheral artery and possible postdilatation angioplasty (the latter for the self-expandable device only) are simulated by considering different idealized vessel geometries and accounting for the presence of a stenotic plaque. Proposed results highlight important differences in the mechanical response of the two types of stents, as well as a significant influence of the vessel shape on the stress distributions arising upon the artery-plaque system. Finally, computational results are used to assess both the stent mechanical performance and the effectiveness of the stenting treatment, allowing also to identify possible critical conditions affecting the risk of stent fracture, tissue damage, and/or pathological tissue response.

  7. Time Sequence Evaluation of Biliary Stent Occlusion by Dissection Analysis of Retrieved Stents.

    PubMed

    Kwon, Chang-Il; Gromski, Mark A; Sherman, Stuart; Easler, Jeffrey J; El Hajj, Ihab I; Watkins, James; Fogel, Evan L; McHenry, Lee; Lehman, Glen A

    2016-08-01

    Multiple factors can affect the occlusion of plastic stents. Previous data demonstrate that side holes may induce more biofilm formation probably via microturbulence and bile flow disturbances that could lead to occlusion. These results, however, have not been replicated in subsequent clinical studies with different methods. The objective of this study is to evaluate the physical characteristics of plastic stent occlusion over time. This is a plastic stent sequential analysis study. Biliary stents removed via ERCP from February 24, 2015, to June 2, 2015, were included. One hundred and forty-eight retrieved straight-type plastic stents were longitudinally cut by a custom-made cutting device. These dissected stents were then evaluated in detail with regard to the location of stent occlusion and the stent patency period. Location of stent occlusive debris was the primary outcome in this study. Biofilm formations and occlusions by debris were sequentially but separately tallied. Biofilm formations were initially seen around the side hole areas within 30 days and spread to the entire stent by 60 days. Then, occlusion process by debris was mainly initiated by 80 days and progressed to full occlusion by median of 90 days. Although some occlusions were also observed around the side hole areas within 30 days, affected areas were more widely observed after biofilm formation. This study is the first to attempt to describe the distribution of stent occlusions over time. These observations may help guide future stent development.

  8. Stent implantation influence wall shear stress evolution

    NASA Astrophysics Data System (ADS)

    Bernad, S. I.; Totorean, A. F.; Bosioc, A. I.; Petre, I.; Bernad, E. S.

    2016-06-01

    Local hemodynamic factors are known affect the natural history of the restenosis critically after coronary stenting of atherosclerosis. Stent-induced flows disturbance magnitude dependent directly on the strut design. The impact of flow alterations around struts vary as the strut geometrical parameters change. Our results provide data regarding the hemodynamic parameters for the blood flow in both stenosed and stented coronary artery under physiological conditions, namely wall shear stress and pressure drop.

  9. Expandable stents: unique devices and clinical uses.

    PubMed

    Ross, Andrew S; Kozarek, Richard A

    2011-07-01

    The use of stents throughout the gastrointestinal tract has evolved over the past century. The evolution of endoscopic ultrasound and significant improvements in stent design are key factors that have allowed endoscopists to drive the use of stents in gastroenterology into new directions. Endoscopic creativity remains crucial in the evolution of any new endoscopic technology. Finally, the use of multidisciplinary teams, including endoscopists, radiologists, and surgeons, allows for the exchange of ideas and procedural planning necessary for successful innovation.

  10. Peripheral Stent Placement in Hemodialysis Grafts

    SciTech Connect

    Kariya, Shuji Tanigawa, Noboru; Kojima, Hiroyuki; Komemushi, Atsushi; Shomura, Yuzo; Shiraishi, Tomokuni; Kawanaka, Toshiaki; Sawada, Satoshi

    2009-09-15

    The purpose of the present study was to evaluate the clinical outcome of peripheral stent placement after failed balloon angioplasty in patients with grafts who are on hemodialysis. We examined 30 Wallstents that were placed in 26 patients because balloon angioplasty failed or early restenosis (<3 months) occurred within 3 months. We retrospectively reviewed 267 consecutive balloon angioplasties performed in 71 patients with graft access between August 2000 and March 2007. Stent placements accounted for 30 (11.2%) of the 267 balloon angioplasties. The clinical success rate of stent placement was 93.3% (28 of 30 stent placements). The 3-, 6-, and 12-month primary patency rates were 73.3%, 39.3%, and 17.7%, respectively. The 1-, 2-, and 3-year secondary patency rates were 90.2%, 83.8%, and 83.8%, respectively. Primary patency was significantly prolonged by stent placement after early restenosis compared with previous balloon angioplasty alone (P = 0.0059). Primary patency after stent placement was significantly lower than after successful balloon angioplasty without indications for stent placement (P = 0.0279). Secondary patency rates did not significantly differ between stent placement and balloon angioplasty alone. The mean number of reinterventions required to maintain secondary patency after stent placement was significantly larger than that after balloon angioplasty alone (Mann-Whitney U test, P = 0.0419). We concluded that peripheral stent placement for graft access is effective for salvaging vascular access after failed balloon angioplasty and for prolonging patency in early restenosis after balloon angioplasty. However, reinterventions are required to maintain secondary patency after stent placement. Furthermore, peripheral stent placement for graft access cannot achieve the same primary patency as balloon angioplasty alone.

  11. Economic evaluation of sirolimus-eluting stents

    PubMed Central

    Shrive, Fiona M.; Manns, Braden J.; Galbraith, P. Diane; Knudtson, Merril L.; Ghali, William A.

    2005-01-01

    Background Sirolimus-eluting stents have recently been shown to reduce the risk of restenosis among patients who undergo percutaneous coronary intervention (PCI). Given that sirolimus-eluting stents cost about 4 times as much as conventional stents, and considering the volume of PCI procedures, the decision to use sirolimus-eluting stents has large economic implications. Methods We performed an economic evaluation comparing treatment with sirolimus-eluting and conventional stents in patients undergoing PCI and in subgroups based on age and diabetes mellitus status. The probabilities of transition between clinical states and estimates of resource use and health-related quality of life were derived from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) database. Information on effectiveness was based on a meta-analysis of randomized controlled clinical trials (RCTs) comparing sirolimus-eluting and conventional stents. Results Cost per quality-adjusted life year (QALY) gained in the baseline analysis was Can$58 721. Sirolimus-eluting stents were more cost-effective in patients with diabetes and in those over 75 years of age, the costs per QALY gained being $44 135 and $40 129, respectively. The results were sensitive to plausible variations in the cost of stents, the estimate of the effectiveness of sirolimus-eluting stents and the assumption that sirolimus-eluting stents would prevent the need for cardiac catheterizations in the subsequent year when no revascularization procedure was performed to treat restenosis. Interpretation The use of sirolimus-eluting stents is associated with a cost per QALY that is similar to or higher than that of other accepted medical forms of therapy and is associated with a significant incremental cost. Sirolimus-eluting stents are more economically attractive for patients who are at higher risk of restenosis or at a high risk of death if a second revascularization procedure were to be required

  12. Photodynamic therapy for occluded biliary metal stents

    NASA Astrophysics Data System (ADS)

    Roche, Joseph V. E.; Krasner, Neville; Sturgess, R.

    1999-02-01

    In this abstract we describe the use of photodynamic therapy (PDT) to recanalize occluded biliary metal stents. In patients with jaundice secondary to obstructed metal stents PDT was carried out 72 hours after the administration of m THPC. Red laser light at 652 nm was delivered endoscopically at an energy intensity of 50 J/cm. A week later endoscopic retrograde cholangiogram showed complete recanalization of the metal stent.

  13. Auxetic oesophageal stents: structure and mechanical properties.

    PubMed

    Ali, Murtaza Najabat; Busfield, James J C; Rehman, Ihtesham U

    2014-02-01

    Oesophageal cancer is the ninth leading cause of malignant cancer death and its prognosis remains poor, ranking as the sixth most frequent cause of death in the world. This research work aims to adopt an Auxetic (rotating-squares) geometry device, that had previously been examined theoretically and analysed by Grima and Evans (J Mater Sci Lett 19(17):1563-1565, 2000), to produce a novel Auxetic oesophageal stent and stent-grafts relevant to the palliative treatment of oesophageal cancer and also for the prevention of dysphagia. This paper discusses the manufacture of a small diameter Auxetic oesophageal stent and stent-graft. The oral deployment of such an Auxetic stent would be simplest if a commercial balloon dilatational catheter was used as this obviates the need for an expensive dedicated delivery system. A novel manufacturing route was employed in this research to develop both Auxetic films and Auxetic oesophageal stents, which ranged from conventional subtractive techniques to a new additive manufacturing method. Polyurethane was selected as a material for the fabrication of Auxetic films and Auxetic oesophageal stents because of its good biocompatibility and non-toxicological properties. The Auxetic films were later used for the fabrication of seamed Auxetic oesophageal stents. The flexible polyurethane tubular grafts were also attached to the inner luminal side of the seamless Auxetic oesophageal stents, in order to prevent tumour in-growth. Scanning electron microscopy was used to conduct surface morphology study by using different Auxetic specimens developed from different conventional and new additive manufacturing techniques. Tensile testing of the Auxetic films was performed to characterise their mechanical properties. The stent expansion tests of the Auxetic stents were done to analyse the longitudinal extension and radial expansion of the Auxetic stent at a range of radial pressures applied by the balloon catheter, and to also identify the pressure

  14. Nitinol stent design - understanding axial buckling.

    PubMed

    McGrath, D J; O'Brien, B; Bruzzi, M; McHugh, P E

    2014-12-01

    Nitinol׳s superelastic properties permit self-expanding stents to be crimped without plastic deformation, but its nonlinear properties can contribute towards stent buckling. This study investigates the axial buckling of a prototype tracheobronchial nitinol stent design during crimping, with the objective of eliminating buckling from the design. To capture the stent buckling mechanism a computational model of a radial force test is simulated, where small geometric defects are introduced to remove symmetry and allow buckling to occur. With the buckling mechanism ascertained, a sensitivity study is carried out to examine the effect that the transitional plateau region of the nitinol loading curve has on stent stability. Results of this analysis are then used to redesign the stent and remove buckling. It is found that the transitional plateau region can have a significant effect on the stability of a stent during crimping, and by reducing the amount of transitional material within the stent hinges during loading the stability of a nitinol stent can be increased.

  15. Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents.

    PubMed

    Zhu, Yue-Qi; Yang, Kai; Edmonds, Laura; Wei, Li-Ming; Zheng, Reila; Cheng, Ruo-Yu; Cui, Wen-Guo; Cheng, Ying-Sheng

    2017-01-01

    We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits. The mechanical compression-recovery characteristics and degradation behaviors of the magnesium stent were investigated in vitro. A total of 45 rabbits were randomly divided into a magnesium- (n = 15) and a plastic- (n = 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group (n = 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination. Silicone-covered magnesium stents showed similar radial force to plastic stents (p > 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks; p > 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups (p > 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group (p < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group (p > 0.05). Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents.

  16. Silicone-covered biodegradable magnesium-stent insertion in the esophagus: a comparison with plastic stents

    PubMed Central

    Zhu, Yue-Qi; Yang, Kai; Edmonds, Laura; Wei, Li-Ming; Zheng, Reila; Cheng, Ruo-Yu; Cui, Wen-Guo; Cheng, Ying-Sheng

    2016-01-01

    Background: We determined the feasibility of, and tissue response to silicone-covered biodegradable magnesium- and plastic-stent insertion into the esophagus in rabbits. Methods: The mechanical compression–recovery characteristics and degradation behaviors of the magnesium stent were investigated in vitro. A total of 45 rabbits were randomly divided into a magnesium- (n = 15) and a plastic- (n = 15) stent group, and underwent stent insertion into the lower third of the esophagus under fluoroscopic guidance; a control group (n = 15) did not undergo the intervention. Esophagography was performed at 1, 2, and 4 weeks. Five rabbits in each group were euthanized at each time point for histological examination. Results: Silicone-covered magnesium stents showed similar radial force to plastic stents (p > 0.05). The magnesium stents degraded rapidly in an acidic solution, but 90.2% ± 3.1% of the residual mass was maintained after a 2-week degradation in a solution with a pH of 4.0. All stent insertions were well tolerated. Magnesium stents migrated in six rabbits (one at 1 week, one at 2 weeks and four at 4 weeks), and plastic stents migrated in three rabbits (one at 2 weeks and two at 4 weeks; p > 0.05). Esophageal wall remodeling (thinner epithelial and smooth muscle layers) was similar in both stented groups (p > 0.05), and the esophagus wall was found to be significantly thinner in the stented groups than in the control group (p < 0.05). Esophageal injury and collagen deposition following stent insertion were similar and did not differ from the control group (p > 0.05). Conclusions: Esophageal silicone-covered magnesium stents provided reliable support for at least 2 weeks, with acceptable migration rates and without causing severe injury or tissue reaction compared with plastic stents. PMID:28286555

  17. Predictive Factors of In-Stent Restenosis in Renal Artery Stenting: A Retrospective Analysis

    SciTech Connect

    Vignali, Claudio Bargellini, Irene; Lazzereschi, Michele; Cioni, Roberto; Petruzzi, Pasquale; Caramella, Davide; Pinto, Stefania; Napoli, Vinicio; Zampa, Virna; Bartolozzi, Carlo

    2005-04-15

    Purpose. To retrospectively evaluate the role of clinical and procedural factors in predicting in-stent restenosis in patients with renovascular disease treated by renal artery stenting. Methods. From 1995 to 2002, 147 patients underwent renal artery stenting for the treatment of significant ostial atherosclerotic stenosis. Patients underwent strict clinical and color-coded duplex ultrasound follow-up. Ninety-nine patients (111 stents), with over 6 months of continuous follow-up (mean 22{+-}12 months, range 6-60 months), were selected and classified according to the presence (group A, 30 patients, 32 lesions) or absence (group B, 69 patients, 79 lesions) of significant in-stent restenosis. A statistical analysis was performed to identify possible preprocedural and procedural predictors of restenosis considering the following data: sex, age, smoking habit, diabetes mellitus, hypertension, serum creatinine, cholesterol and triglyceride levels, renal artery stenosis grade, and stent type, length and diameter. Results. Comparing group A and B patients ({chi}{sup 2} test), a statistically significant relation was demonstrated between stent diameter and length and restenosis: the risk of in-stent restenosis decreased when the stent was {>=}6 mm in diameter and between 15 and 20 mm in length. This finding was confirmed by multiple logistic regression analysis. Stent diameter and length were proved to be significantly related to in-stent restenosis also when evaluating only patients treated by Palmaz stent (71 stents). Conclusion. Although it is based on a retrospective analysis, the present study confirms the importance of correct stent selection in increasing long-term patency, using stents of at least 6 mm in diameter and with a length of approximately 15-20 mm.

  18. Neointimal Hyperplasia in Low-Profile Nitinol Stents, Palmaz Stents, and Wallstents: A Comparative Experimental Study

    SciTech Connect

    Schuermann, Karl; Vorwerk, Dierk; Kulisch, Arthur; Stroehmer-Kulisch, Eva; Biesterfeld, Stefan; Stopinski, Tadeusz; Guenther, Rolf W.

    1996-04-15

    Purpose: To compare neointima formation following insertion of low-profile Nitinol stents, Palmaz stents, and Wallstents. Methods: Nitinol stents, Palmaz stents, and Wallstents similar in size were transfemorally inserted into the iliac arteries of 12 sheep. Four stents per sheep were deployed; the position of the stents was varied so that each type of stent was placed in each position (right or left, proximal or distal) with equal frequency. Stent patency was followed by angiography. Six sheep were euthanized after 1 month, and the remaining six after 6 months. Iliac arteries were removed en bloc and prepared for histological examination. Neointimal and medial thickness were measured by light microscopy, and measurements were analyzed statistically. Results: Mean neointimal thickness both over (NO) and between (NB) the stent struts was greater in Wallstents (NO = 0.341 mm, NB = 0.368 mm) than in the Nitinol (NO = 0.260 mm, NB = 0.220 mm) and Palmaz stents (NO = 0.199 mm, NB = 0.204 mm), but differences were not significant (p> 0.05). Medial atrophy in the area between the stent struts was greater in Wallstents compared with Nitinol and Palmaz stents (p < 0.007 and p < 0.02, respectively); in the area under the stent struts there was a significant difference only between Palmaz stents and Wallstents (p < 0.02). Conclusion: Under defined experimental conditions, none of the three types of stent appears to be preferable to the others regarding neointima formation in the short- to mid-term follow-up period.

  19. Evaluation of the compressive mechanical properties of endoluminal metal stents.

    PubMed

    Schrader, S C; Beyar, R

    1998-06-01

    The mechanical properties of metal stents are important parameters in the consideration of stent design, matched to resist arterial recoil and vascular spasm. The purpose of this study was to develop a system for a standardized quantitative evaluation of the mechanical characteristics of various coronary stents. Several types of stents were compressed by external hydrostatic pressure. The stent diameter was assessed by placing a pair of small ultrasonic sono-crystals on the stent. From pressure-strain diagrams the ultimate strength and radial stiffness for each stent were determined. For all stents, except the MICRO-II and the Wiktor stent, the diameter decreased homogeneously until an ultimate compressive strength was exceeded, causing an abrupt collapse. Expanded to 3 mm, the mechanical behavior of the beStent, the Crown and the Palmaz-Schatz stent (PS153-series) were comparable. The spiral articulated Palmaz-Schatz stent showed twice the strength (1.26 atm) of the PS-153 (0.65 atm). The NIR stent yielded a maximum strength of 1.05 atm. The MICRO-II and the Wiktor stent did not collapse abruptly but rather showed a continuous decline of diameter with increasing external pressure. The Cardiocoil stent behaved in a fully elastic manner and showed the largest radial stiffness. Difference in mechanical properties between stents were documented using a new device specifically developed for that purpose. These mechanical stent parameters may have important clinical implications.

  20. [Stent-assisted recanalization of femoropopliteal arterial occlusive disease. Influence of stent design on patency rates].

    PubMed

    Treitl, M; Reiser, M F; Treitl, K M

    2016-03-01

    Despite enormous technical progress the results of endovascular treatment of the femoropopliteal vasculature are unsatisfactory and its role is still controversially discussed. In the past decade numerous new stent designs have come onto the market but it is unclear whether they have benefits with respect to patency rates. Comparison of published data on patency rates and target lesion revascularization rates after use of different stent designs in the femoropopliteal vasculature. Analysis of 25 published studies and registries from 2006 to 2015 for classical open-cell stents, interwoven stents and partially or fully covered stents. The published data are heterogeneous and comparative studies for different stent designs are completely missing. Over the past decade the patency rates after femoropopliteal stenting could be improved. According to available data stenting of short lesions < 5 cm does not show any benefit compared to isolated balloon angioplasty. Primary stenting is now recommended for intermediate and longer lesions > 6.4 cm. Due to the heterogeneity of published data a clear benefit for a specific stent design is not obvious; however, data for interwoven stents are promising and show a tendency towards improved patency, at least for certain lesions. Randomized controlled comparative trials are needed to confirm this result.

  1. Initial experience with paclitaxel-coated stents.

    PubMed

    Grube, Eberhard; Büllesfeld, Lutz

    2002-12-01

    Local delivery of immunosuppressive or antiproliferative agents using a drug-eluting stent is a new technology that is supposed to inhibit in-stent restenosis, thus providing a biological and mechanical solution. This technique is a very promising. To date, several agents have been used, including paclitaxel, QP-2, rapamycin, actinomycin D, dexamethason, tacrolimus, and everolimus. Several studies, published recently or still ongoing, have evaluated these drugs as to their release kinetics, effective dosage, safety in clinical practice, and benefit. These studies include: SCORE (paclitaxel derivative), TAXUS I-VI, ELUTES, ASPECT, DELIVER (paclitaxel), RAVEL, SIRIUS (sirolimus), ACTION (actinomycin), EVIDENT, PRESENT (tacrolimus), EMPEROR (dexamethason), and FUTURE (everolimus). Paclitaxel was one of the first stent-based antiproliferative agents under clinical investigation that provided profound inhibition of neointimal thickening depending on delivery duration and drug dosage. The randomized, multicenter SCORE trail (Quanam stent, paclitaxel-coated) enrolled 266 patients at 17 sites. At 6-month's follow-up, a drop of 83% in stent restenosis using the drug-eluting stent could be achieved (6.4% drug-eluting stent vs 36.9% control group), which was attributable to a remarkable decrease in intimal proliferation. Unfortunately, due to frequent stent thrombosis and side-branch occlusions, the reported 30-day MACE rate was 10.2%. The randomized TAXUS-I safety trial (BSC, NIRx, paclitaxel-coated) also demonstrated beneficial reduction of restenotic lesions at 6-month's follow-up (0% vs 10%) but was associated with the absence of thrombotic events presumably due to less drug dosage. The ongoing TAXUS II-VI trials are addressing additional insight regarding the efficacy of the TAXUS paclitaxel-eluting stent. ASPECT and ELUTES evaluated paclitaxel-coated stents (i.e., Cook and Supra G), including subgroups with different drug dosages. With respect to stent restenosis and

  2. Iliocaval Confluence Stenting for Chronic Venous Obstructions

    SciTech Connect

    Graaf, Rick de; Wolf, Mark de; Sailer, Anna M.; Laanen, Jorinde van Wittens, Cees; Jalaie, Houman

    2015-10-15

    PurposeDifferent techniques have been described for stenting of venous obstructions. We report our experience with two different confluence stenting techniques to treat chronic bi-iliocaval obstructions.Materials and MethodsBetween 11/2009 and 08/2014 we treated 40 patients for chronic total bi-iliocaval obstructions. Pre-operative magnetic resonance venography showed bilateral extensive post-thrombotic scarring in common and external iliac veins as well as obstruction of the inferior vena cava (IVC). Stenting of the IVC was performed with large self-expandable stents down to the level of the iliocaval confluence. To bridge the confluence, either self-expandable stents were placed inside the IVC stent (24 patients, SECS group) or high radial force balloon-expandable stents were placed at the same level (16 patients, BECS group). In both cases, bilateral iliac extensions were performed using nitinol stents.ResultsRecanalization was achieved for all patients. In 15 (38 %) patients, a hybrid procedure with endophlebectomy and arteriovenous fistula creation needed to be performed because of significant involvement of inflow vessels below the inguinal ligament. Mean follow-up was 443 ± 438 days (range 7–1683 days). For all patients, primary, assisted-primary, and secondary patency rate at 36 months were 70, 73, and 78 %, respectively. Twelve-month patency rates in the SECS group were 85, 85, and 95 % for primary, assisted-primary, and secondary patency. In the BECS group, primary patency was 100 % during a mean follow-up period of 134 ± 118 (range 29–337) days.ConclusionStenting of chronic bi-iliocaval obstruction shows relatively high patency rates at medium follow-up. Short-term patency seems to favor confluence stenting with balloon-expandable stents.

  3. Bioresorbable ureteral stents from natural origin polymers.

    PubMed

    Barros, Alexandre A; Rita, Ana; Duarte, C; Pires, Ricardo A; Sampaio-Marques, Belém; Ludovico, Paula; Lima, Estevão; Mano, João F; Reis, Rui L

    2015-04-01

    In this work, stents were produced from natural origin polysaccharides. Alginate, gellan gum, and a blend of these with gelatin were used to produce hollow tube (stents) following a combination of templated gelation and critical point carbon dioxide drying. Morphological analysis of the surface of the stents was carried out by scanning electron microscopy. Indwelling time, encrustation, and stability of the stents in artificial urine solution was carried out up to 60 days of immersion. In vitro studies carried out with simulated urine demonstrated that the tubes present a high fluid uptake ability, about 1000%. Despite this, the materials are able to maintain their shape and do not present an extensive swelling behavior. The bioresorption profile was observed to be highly dependent on the composition of the stent and it can be tuned. Complete dissolution of the materials may occur between 14 and 60 days. Additionally, no encrustation was observed within the tested timeframe. The ability to resist bacterial adherence was evaluated with Gram-positive Staphylococcus aureus and two Gram-negatives Escherichia coli DH5 alpha and Klebsiella oxytoca. For K. oxytoca, no differences were observed in comparison with a commercial stent (Biosoft(®) duo, Porges), although, for S. aureus all tested compositions had a higher inhibition of bacterial adhesion compared to the commercial stents. In case of E. coli, the addition of gelatin to the formulations reduced the bacterial adhesion in a highly significant manner compared to the commercial stents. The stents produced by the developed technology fulfill the requirements for ureteral stents and will contribute in the development of biocompatible and bioresorbable urinary stents.

  4. Carotid artery stenting: current and emerging options

    PubMed Central

    Morr, Simon; Lin, Ning; Siddiqui, Adnan H

    2014-01-01

    Carotid artery stenting technologies are rapidly evolving. Options for endovascular surgeons and interventionists who treat occlusive carotid disease continue to expand. We here present an update and overview of carotid stenting devices. Evidence supporting carotid stenting includes randomized controlled trials that compare endovascular stenting to open surgical endarterectomy. Carotid technologies addressed include the carotid stents themselves as well as adjunct neuroprotective devices. Aspects of stent technology include bare-metal versus covered stents, stent tapering, and free-cell area. Drug-eluting and cutting balloon indications are described. Embolization protection options and new direct carotid access strategies are reviewed. Adjunct technologies, such as intravascular ultrasound imaging and risk stratification algorithms, are discussed. Bare-metal and covered stents provide unique advantages and disadvantages. Stent tapering may allow for a more fitted contour to the caliber decrement between the common carotid and internal carotid arteries but also introduces new technical challenges. Studies regarding free-cell area are conflicting with respect to benefits and associated risk; clinical relevance of associated adverse effects associated with either type is unclear. Embolization protection strategies include distal filter protection and flow reversal. Though flow reversal was initially met with some skepticism, it has gained wider acceptance and may provide the advantage of not crossing the carotid lesion before protection is established. New direct carotid access techniques address difficult anatomy and incorporate sophisticated flow-reversal embolization protection techniques. Carotid stenting is a new and exciting field with rapidly advancing technologies. Embolization protection, low-risk deployment, and lesion assessment and stratification are active areas of research. Ample room remains for further innovations and developments. PMID:25349483

  5. Forgotten biliary stents: ignorance is not bliss.

    PubMed

    Kumar, Saket; Chandra, Abhijit; Kulkarni, Rugved; Maurya, Ajeet Pratap; Gupta, Vishal

    2017-06-22

    Endoscopic biliary stenting is a common procedure in routine gastroenterology practice. Plastic stents are the most common type of stents used and are indicated mainly for short-term biliary drainage. Prolonged indwelling plastic stents can result in disastrous complications. We conducted a retrospective analysis of patients who presented with complications of forgotten biliary stents in a tertiary care hospital during January 2010 to October 2016. All patients were managed either by endoscopic or surgical means. Details of these patients were obtained from departmental patient database, endoscopy records, and surgical register. A total of 21 cases of retained biliary stents were managed in the study period and their outcome was analyzed. The median age was 47 years (range 17-70 years) and 17 (80.9%) patients were female. Primary indication of biliary stenting was stone disease in 76.2% (n = 16), while benign biliary stricture accounted for 19% of cases (n = 4). Mean duration at presentation to hospital after ERCP stenting was 3.53 years (range 1-14 years), with cholangitis being the most common presentation (66.67%). Definitive endoscopic treatment for forgotten stent and its associated complication was possible only in five patients (23.8%); in remaining 16 (76.2%) cases, surgical exploration was required. Despite life-threatening complications and major surgical interventions, no mortality was recorded. Instances of forgotten biliary stents presenting with serious complications are not uncommon in Indian setup. Patients either ignore advice for timely stent removal or are unaware of the presence of endoprosthesis or need for removal. Adequate patient counseling, information, and proper documentation are essential to avoid this condition.

  6. The conical stent in coronary artery improves hemodynamics compared with the traditional cylindrical stent.

    PubMed

    Yu, Yi; Zhou, Yujie; Ma, Qian; Jia, Shuo; Wu, Sijing; Sun, Yan; Liu, Xiaoli; Zhao, Yingxin; Liu, Yuyang; Shi, Dongmei

    2017-01-15

    This study sought to explore the efficacy of the conical stent implantation in the coronary artery by comparing the effects of cylindrical and conical stents on wall shear stress (WSS) and velocity of flow and fractional flow reserve (FFR). The traditional cylindrical stent currently used in the percutaneous coronary intervention (PCI) has a consistent diameter, which does not match the physiological change of the coronary artery. On the contrary, as a new patent, the conical stent with tapering lumen is consistent with the physiological change of vascular diameter. However, the effect of the conical stent implantation on the coronary hemodynamics remains unclear. The coronary artery, artery stenosis and two stent models were established by Solidworks software. All models were imported into the computational fluid dynamics (CFD) software ANSYS ICEM-CFD to establish the fluid model. After the boundary conditions were set, CFD analysis was proceeded to compare the effects of two stent implantation on the change of WSS, velocity of flow and FFR. Hemodynamic indexes including FFR, blood flow velocity distribution (BVD) and WSS were improved by either the cylindrical or the conical stent implantation. However, after the conical stent implantation, the change of FFR seemed to be slower and more homogenous; the blood flow velocity was more appropriate without any obvious blood stagnation and direction changes; the WSS after the conical stent implantation was uniform from the proximal to distal side of the stent. Compared with the cylindrical stent, the conical stent implantation in the coronary artery can make the changes of vascular hemodynamic more closer to the physiological condition, which can reduce the incidence of intra-stent restenosis and thrombosis, thus making it more suitable for PCI therapy. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. Initial Experience with the Resonance Metallic Stent for Antegrade Ureteric Stenting

    SciTech Connect

    Wah, Tze M. Irving, Henry C.; Cartledge, Jon

    2007-07-15

    Background and purpose. We describe our initial experience with a new metallic ureteric stent which has been designed to provide long-term urinary drainage in patients with malignant ureteric strictures. The aim is to achieve longer primary patency rates than conventional polyurethane ureteric stents, where encrustation and compression by malignant masses limit primary patency. The Resonance metallic double-pigtail ureteric stent (Cook, Ireland) is constructed from coiled wire spirals of a corrosion-resistant alloy designed to minimize tissue in-growth and resist encrustation, and the manufacturer recommends interval stent change at 12 months. Methods. Seventeen Resonance stents were inserted via an antegrade approach into 15 patients between December 2004 and March 2006. The causes of ureteric obstruction were malignancies of the bladder (n = 4), colon (n = 3), gynecologic (n = 5), and others (n = 3). Results. One patient had the stent changed after 12 months, and 3 patients had their stents changed at 6 months. These stents were draining adequately with minimal encrustation. Four patients are still alive with functioning stents in situ for 2-10 months. Seven patients died with functioning stents in place (follow-up periods of 1 week to 8 months). Three stents failed from the outset due to bulky pelvic malignancy resulting in high intravesical pressure, as occurs with conventional plastic stents. Conclusion. Our initial experience with the Resonance metallic ureteric stent indicates that it may provide adequate long-term urinary drainage (up to 12 months) in patients with malignant ureteric obstruction but without significantly bulky pelvic disease. This obviates the need for regular stent changes and would offer significant benefit for these patients with limited life expectancy.

  8. Bare metal stents, durable polymer drug eluting stents, and biodegradable polymer drug eluting stents for coronary artery disease: mixed treatment comparison meta-analysis

    PubMed Central

    Toklu, Bora; Amoroso, Nicholas; Fusaro, Mario; Kumar, Sunil; Hannan, Edward L; Faxon, David P; Feit, Frederick

    2013-01-01

    Objective To compare the efficacy and safety of biodegradable polymer drug eluting stents with those of bare metal stents and durable polymer drug eluting stents. Design Mixed treatment comparison meta-analysis of 258 544 patient years of follow-up from randomized trials. Data sources and study selection PubMed, Embase, and Central were searched for randomized trials comparing any of the Food and Drug Administration approved durable polymer drug eluting stents (sirolimus eluting, paclitaxel eluting, cobalt chromium everolimus eluting, platinum chromium everolimus eluting, zotarolimus eluting-Endeavor, and zotarolimus eluting-Resolute) or biodegradable polymer drug eluting stents, with each other or against bare metal stents. Outcomes Long term efficacy (target vessel revascularization, target lesion revascularization) and safety (death, myocardial infarction, stent thrombosis). Landmark analysis at more than one year was evaluated to assess the potential late benefit of biodegradable polymer drug eluting stents. Results From 126 randomized trials and 258 544 patient years of follow-up, for long term efficacy (target vessel revascularization), biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.66, 95% credibility interval 0.57 to 0.78) and zotarolimus eluting stent-Endeavor (0.69, 0.56 to 0.84) but not to newer generation durable polymer drug eluting stents (for example: 1.03, 0.89 to 1.21 versus cobalt chromium everolimus eluting stents). Similarly, biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.61, 0.37 to 0.89) but inferior to cobalt chromium everolimus eluting stents (2.04, 1.27 to 3.35) for long term safety (definite stent thrombosis). In the landmark analysis after one year, biodegradable polymer drug eluting stents were superior to sirolimus eluting stents for definite stent thrombosis (rate ratio 0.29, 0.10 to 0.82) but were associated with increased

  9. Bare metal stents, durable polymer drug eluting stents, and biodegradable polymer drug eluting stents for coronary artery disease: mixed treatment comparison meta-analysis.

    PubMed

    Bangalore, Sripal; Toklu, Bora; Amoroso, Nicholas; Fusaro, Mario; Kumar, Sunil; Hannan, Edward L; Faxon, David P; Feit, Frederick

    2013-11-08

    To compare the efficacy and safety of biodegradable polymer drug eluting stents with those of bare metal stents and durable polymer drug eluting stents. Mixed treatment comparison meta-analysis of 258,544 patient years of follow-up from randomized trials. PubMed, Embase, and Central were searched for randomized trials comparing any of the Food and Drug Administration approved durable polymer drug eluting stents (sirolimus eluting, paclitaxel eluting, cobalt chromium everolimus eluting, platinum chromium everolimus eluting, zotarolimus eluting-Endeavor, and zotarolimus eluting-Resolute) or biodegradable polymer drug eluting stents, with each other or against bare metal stents. Long term efficacy (target vessel revascularization, target lesion revascularization) and safety (death, myocardial infarction, stent thrombosis). Landmark analysis at more than one year was evaluated to assess the potential late benefit of biodegradable polymer drug eluting stents. From 126 randomized trials and 258,544 patient years of follow-up, for long term efficacy (target vessel revascularization), biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.66, 95% credibility interval 0.57 to 0.78) and zotarolimus eluting stent-Endeavor (0.69, 0.56 to 0.84) but not to newer generation durable polymer drug eluting stents (for example: 1.03, 0.89 to 1.21 versus cobalt chromium everolimus eluting stents). Similarly, biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.61, 0.37 to 0.89) but inferior to cobalt chromium everolimus eluting stents (2.04, 1.27 to 3.35) for long term safety (definite stent thrombosis). In the landmark analysis after one year, biodegradable polymer drug eluting stents were superior to sirolimus eluting stents for definite stent thrombosis (rate ratio 0.29, 0.10 to 0.82) but were associated with increased mortality compared with cobalt chromium everolimus eluting stents (1.52, 1

  10. Management of occluded metal stents in malignant biliary obstruction: similar outcomes with second metal stents compared to plastic stents.

    PubMed

    Shah, Tilak; Desai, Svetang; Haque, Mahfuzul; Dakik, Hassan; Fisher, Deborah

    2012-11-01

    Covered or uncovered self expandable metallic stents (SEMS) placed in patients with malignant biliary obstruction can occlude in 19-40 %, but optimal management is unclear. We sought to summarize current evidence regarding management of occluded SEMS in patients with malignant biliary obstruction. Two investigators independently searched Pubmed, Embase, and Web of Science using pre-defined search criteria, and reviewed bibliographies of included studies. Data were independently abstracted by two investigators, and analyzed using RevMan. We compared strategies of second SEMS versus plastic stents with respect to the following outcomes: rate of second stent re-occlusion, duration of second stent patency, and survival. Ten retrospective studies met inclusion criteria for the systematic review. Management options described were placement of an uncovered SEMS (n = 125), covered SEMS (n = 106), plastic stent (n = 135), percutaneous biliary drain (n = 7), mechanical cleaning (n = 18), or microwave coagulation (n = 7). Relative risk of re-occlusion was not significantly different in patients with second SEMS compared to plastic stents (RR 1.24, 95 % CI 0.92, 1.67, I(2) = 0, p 0.16). Duration of second stent patency was not significantly different between patients who received second SEMS versus plastic stents (weighted mean difference 0.46, 95 % CI -0.30, 1.23, I(2) = 83 %). Survival was not significantly different among patients who received plastic stents versus SEMS (weighted mean difference -1.13, 95 % CI -2.33, 0.07, I(2) 86 %, p = 0.07). Among patients with malignant biliary obstruction and occluded SEMS, available evidence suggests a strategy of placing a plastic stent may be as effective as second SEMS. Limitations of these findings were that all studies were retrospective and heterogeneity between studies was detected for two of the outcomes.

  11. Routine intraoperative stenting for renal transplant recipients.

    PubMed

    Wilson, Colin H; Bhatti, Aftab A; Rix, David A; Manas, Derek M

    2005-10-15

    Major urological complications (MUCs) after kidney transplantation contribute to patient morbidity and compromise graft function. Ureteric stents have been successfully used to treat such complications and a number of centers have adopted a policy of universal prophylactic stenting, at the time of graft implantation, to reduce the incidence of urine leaks and ureteric stenosis. In conjunction with the Cochrane Renal Group we searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, reference lists of articles, books and abstracts and contacted companies, authors and experts to identify randomized controlled trials examining the use of stents in renal transplantation. The primary outcome was the incidence of MUCs and data on this statistic was pooled and analyzed using a random effects model. Seven randomized controlled trials (1154 patients) of low or moderate quality were identified. The incidence of MUCs was significantly reduced (relative risk [RR] 0.24; 95% CI: 0.07 - 0.77; P=0.02; number needed to treat = 13) by prophylactic ureteric stenting. Urinary tract infections were more common in stented patients (RR 1.49), unless the patients were prescribed 480 mg cotrimoxazole once daily. With this antibiotic regime the incidence of infection was equivalent between the two groups (RR 0.97). Stents appeared generally well tolerated, although trials using longer stents (> or = 20 cm) for longer periods of time (>6 weeks) reported more problems with encrustation and migration. Universal prophylactic stenting reduces the incidence of MUCs and should be recommended on the basis of currently available randomized controlled trials.

  12. Microfabrication and Nanotechnology in Stent Design

    PubMed Central

    Martinez, Adam W.; Chaikof, Elliot L.

    2012-01-01

    Intravascular stents were first introduced in the 1980s as an adjunct to primary angioplasty for management of early complications, including arterial dissection, or treatment of an inadequate technical outcome due to early elastic recoil of the atherosclerotic lesion. Despite the beneficial effects of stenting, persistent high rates of restenosis motivated the design of drug eluting stents for delivery of agents to limit the proliferative and other inflammatory responses within the vascular wall that contribute to the development of a restenotic lesion. These strategies have yielded a significant reduction in the incidence of restenosis, but challenges remain, including incomplete repair of the endothelium at the site of vascular wall injury that may be associated with a late risk of thrombosis. A failure of vessel wall healing has been attributed to primarily to the use of polymeric stent coatings, but the effects of the eluted drug and other material properties or design features of the stent cannot be excluded. Improvements in stent microfabrication, as well as the introduction of alternative materials may help to address those limitations that inhibit stent performance. This review describes the application of novel microfabrication processes and the evolution of new nanotechnologies that hold significant promise in eliminating existing shortcomings of current stent platforms. PMID:21462356

  13. Optimised system configuration for stent manufacturing.

    PubMed

    Rekowski, Ron

    2008-01-01

    Optimising the major components of a laser stent machining platform will lead to improved part quality and machine throughput. Mechanical, control and software elements are reviewed here. Trends in stent design are also discussed together with their implications on these machine design elements.

  14. Rescue coronary stenting in acute myocardial infarction

    NASA Astrophysics Data System (ADS)

    Barbieri, Enrico; Meneghetti, Paolo; Molinari, Gionata; Zardini, Piero

    1996-01-01

    Failed rescue coronary angioplasty is a high risk situation because of high mortality. Coronary stent has given us the chance of improving and maintaining the patency of the artery. We report our preliminary experience of rescue stenting after unsuccessful coronary angioplasty.

  15. Improved image guidance of coronary stent deployment

    NASA Astrophysics Data System (ADS)

    Close, Robert A.; Abbey, Craig K.; Whiting, James S.

    2000-04-01

    Accurate placement and expansion of coronary stents is hindered by the fact that most stents are only slightly radiopaque, and hence difficult to see in a typical coronary x-rays. We propose a new technique for improved image guidance of multiple coronary stents deployment using layer decomposition of cine x-ray images of stented coronary arteries. Layer decomposition models the cone-beam x-ray projections through the chest as a set of superposed layers moving with translation, rotation, and scaling. Radiopaque markers affixed to the guidewire or delivery balloon provide a trackable feature so that the correct vessel motion can be measured for layer decomposition. In addition to the time- averaged layer image, we also derive a background-subtracted image sequence which removes moving background structures. Layer decomposition of contrast-free vessels can be used to guide placement of multiple stents and to assess uniformity of stent expansion. Layer decomposition of contrast-filled vessels can be used to measure residual stenosis to determine the adequacy of stent expansion. We demonstrate that layer decomposition of a clinical cine x-ray image sequence greatly improves the visibility of a previously deployed stent. We show that layer decomposition of contrast-filled vessels removes background structures and reduces noise.

  16. Stent Fracture: How Frequently Is It Recognized?

    PubMed Central

    Mohsen, Mohammed Khalil; Alqahtani, Awad; Al suwaidi, Jassim

    2013-01-01

    In spite of there being several case reports, coronary stent fracture is not a well-recognized entity and incidence rates are likely to be underestimated. In this article, we review different aspects of stent fracture, including incidence, classification, predictors, outcome, diagnosis, and management. PMID:23983912

  17. Primary Stenting of Intracranial Atherosclerotic Stenoses

    SciTech Connect

    Straube, T. Stingele, Robert; Jansen, Olav

    2005-04-15

    Purpose: To determine the feasibility and safety of stenting intracranial atherosclerotic stenoses.Methods: In 12 patients the results of primary intracranial stenting were evaluated retrospectively. Patient ages ranged from 49 to 79 years (mean 64 years). Six patients presented with stenoses in the anterior circulation, and six had stenosis in the posterior circulation. One patient presented with extra- and intracranial tandem stenosis of the left internal carotid artery. Three patients presented with acute basilar thrombosis, caused by high-grade basilar stenoses.Results: Intracranial stenoses were successfully stented in 11 of 12 patients. In one patient the stent could not be advanced over the carotid siphon to reach the stenosis of the ophthalmic internal carotid artery. Follow-up digital subtraction angiographic studies were obtained in two patients who had presented with new neurologic signs or symptoms. In both cases the angiogram did not show any relevant stenotic endothelial hyperplasia. In one patient, after local thrombolysis the stenosis turned out to be so narrow that balloon angioplasty had to be performed before stent deployment. All three patients treated for stenosis-related basilar thrombosis died due to brainstem infarction that had ensued before the intervention.Conclusions: Prophylactic primary stenting of intracranial stenoses of the anterior or posterior cerebral circulation can be performed with a low complication rate; technical problems such as stent flexibility must still be solved. Local thrombolysis followed by stenting in stenosis-related thrombotic occlusion is technically possible.

  18. Late Stent Thrombosis Associated with Heavy Exercise

    PubMed Central

    Simsek, Ziya; Arslan, Sakir; Gundogdu, Fuat

    2009-01-01

    Bare-metal stents are commonly used in the treatment of coronary artery disease. Stent thrombosis usually occurs within the first 48 hours after stent deployment. After a week, the incidence of thrombosis is low. Late stent thrombosis (after 30 days) is rarely seen; however, its clinical outcomes are severe 30-day mortality rates of 20% to 48% and myocardial infarction rates of 60% to 70%. Herein, we present the case and discuss the treatment of a patient who, after heavy exercise, experienced acute myocardial infarction due to late thrombosis in a bare-metal stent. A 54-year-old man presented with unstable angina pectoris. Coronary angiography revealed critical occlusion of the middle right coronary artery. A bare-metal stent was implanted, and he was discharged from the hospital on a medical regimen. Eleven months later, he presented with acute myocardial infarction, which had developed after heavy exercise. Coronary angiography revealed occlusion of the stent in the right coronary artery. After the occlusion was crossed with a guidewire, balloon angioplasty was applied, and Thrombosis-in-Myocardial-Infarction (TIMI)-3 flow was restored. The patient was asymptomatic during his 5-day hospitalization and was discharged on dual antiplatelet therapy. In addition to presenting this patient's case, we discuss mechanisms that may contribute to late stent thrombosis, implications of the condition, and preventive therapy. PMID:19436813

  19. Microfabrication and nanotechnology in stent design.

    PubMed

    Martinez, Adam W; Chaikof, Elliot L

    2011-01-01

    Intravascular stents were first introduced in the 1980s as an adjunct to primary angioplasty for management of early complications, including arterial dissection, or treatment of an inadequate technical outcome due to early elastic recoil of the atherosclerotic lesion. Despite the beneficial effects of stenting, persistent high rates of restenosis motivated the design of drug-eluting stents for delivery of agents to limit the proliferative and other inflammatory responses within the vascular wall that contribute to the development of a restenotic lesion. These strategies have yielded a significant reduction in the incidence of restenosis, but challenges remain, including incomplete repair of the endothelium at the site of vascular wall injury that may be associated with a late risk of thrombosis. A failure of vessel wall healing has been attributed primarily to the use of polymeric stent coatings, but the effects of the eluted drug and other material properties or design features of the stent cannot be excluded. Improvements in stent microfabrication, as well as the introduction of alternative materials may help to address those limitations that inhibit stent performance. This review describes the application of novel microfabrication processes and the evolution of new nanotechnologies that hold significant promise in eliminating existing shortcomings of current stent platforms.

  20. Next generation biodegradable ureteral stent in a yucatan pig model.

    PubMed

    Chew, Ben H; Lange, Dirk; Paterson, Ryan F; Hendlin, Kari; Monga, Manoj; Clinkscales, Kenneth W; Shalaby, Shalaby W; Hadaschik, Boris A

    2010-02-01

    Ureteral stents are commonly used to facilitate kidney drainage but they may produce significant stent symptoms and morbidity, and require a secondary procedure for removal. Previous biodegradable stents showed bio-incompatibility or inconsistent degradation, requiring extra procedures to remove undegraded stent fragments. We previously reported a first generation biodegradable stent composed of suture-like material that required placement through the lumen of a sheath and degraded by 10 weeks. We now report second and third generation biodegradable stents that degrade more rapidly and can be placed directly over a polytetrafluoroethylene guidewire. Two groups of 16 Yucatan pigs each were unilaterally stented endoscopically with a control nondegradable (biostable) stent or a second generation degradable Uriprene stent. Blood studies, renal ultrasound and excretory urography were done throughout the study to determine renal function, hydronephrosis and stent degradation. Genitourinary organs were harvested at necropsy for pathological analysis. A third generation stent designed to improve degradation time was bilaterally implanted endoscopically into 4 Yorkshire Farm pigs (total of 8 stents), followed by excretory urography weekly to assess degradation and kidney function. Biomaterial parameters were tested. Second generation stents began degrading at 2 weeks and were completely degraded by 10 weeks. All third generation stents were degraded by 4 weeks. Hydronephrosis was considerably less in the Uriprene group than in control biostable stented kidneys. Biostable stented ureters showed an average higher degree of inflammation, uropathy and nephropathy. Physical characteristics indicate that Uriprene stents are significantly more resistant to stent compression and have markedly higher tensile strength and coil strength comparable to that of other commercially available plastic stents. Our study confirms that Uriprene stents are biocompatible and provide good renal

  1. Mesenchymal stem cell seeding promotes reendothelialization of the endovascular stent.

    PubMed

    Wu, Xue; Wang, Guixue; Tang, Chaojun; Zhang, Dechuan; Li, Zhenggong; Du, Dingyuan; Zhang, Zhengcai

    2011-09-01

    This study is designed to make a novel cell seeding stent and to evaluate reendothelialization and anti-restenosis after the stent implantation. In comparison with cell seeding stents utilized in previous studies, Mesenchymal stem cells (MSCs) have advantages on promoting of issue repair. Thus it was employed to improve the reendothelialization effects of endovascular stent in present work. MSCs were isolated by density gradient centrifugation and determined as CD29(+) CD44(+) CD34(-) cells by immunofluorescence and immunocytochemistry; gluten and polylysine coated stents were prepared by ultrasonic atomization spray, and MSCs seeded stents were made through rotation culture according to the optimized conditions that were determined in previous studies. The results from animal experiments, in which male New Zealand white rabbits were used, show that the reendothelialization of MSCs coated stents can be completed within one month; in comparison with 316L stainless steel stents (316L SS stents) and gluten and polylysine coated stents, the intimal hyperplasia and in-stent restenosis are significantly inhibited by MSCs coated stents. Endovascular stent seeded with MSCs promotes reendothelialization and inhibits the intimal hyperplasia and in-stent restenosis compared with the 316L SS stents and the gluten and polylysine coated stents.

  2. Stent Graft in Managing Juxta-Renal Aortoiliac Occlusion

    SciTech Connect

    Prabhudesai, V. Mitra, K.; West, D. J.; Dean, M. R. E.

    2003-09-15

    Endovascular procedures are frequently used as an alternative to surgical bypass in aortic and iliac occlusion. Stents have revolutionized the scope of such endovascular procedures, but there are few reports of stents or stent grafts in occlusive juxta-renal aortic occlusion. We present a case where such occlusion was managed by use of a stent graft with successful outcome.

  3. [The bioresorbable coronary stent: a revolution].

    PubMed

    Koegler, Flora; De Benedetti, Edoardo

    2013-04-10

    Coronary angioplasty has undergone several technological revolutions: starting with balloon angioplasty, then with bare metal stent and finally with drug eluting stent (DES), this technique is now mature. However, once we thought the problem of instent restenosis solved with DES, new concerns arise with late and very late stent thrombosis. Should we therefore proscribe DES? How long should be the duration of dual antiplatelet therapy? And how should we manage the patients who need a surgery and are at high risk of bleeding? Are bioresorbable stents the final solution with their initial mechanical properties, then with their drug eluting effect against intra-stent restenosis, and finally with their complete resorption which leaves the artery free of any foreign material?

  4. Clinical experience with ureteral metal stents

    PubMed Central

    Al Aown, Abdulrahman; Iason, Kyriazis; Panagiotis, Kallidonis; Liatsikos, Evangelos N.

    2010-01-01

    Ureteral metal stents (MSs) present a minimally invasive tool to preserve the drainage of renal pelvis whenever ureteral patency is at risk to be obstructed due to extrinsic or intrinsic etiologies. Clinical experience with these stents demonstrates that they impose a promising alternative treatment option in ureteral pathologies that are difficult to be treated via common polymeric stents. Current application of MSs in the treatment of both benign and malignant ureteral obstruction reveals quite promising results. Nevertheless, the ideal MS that would provide uncomplicated long-term effectiveness is still lucking and current MS usage is facing several adverse effects between which stent obstruction, encrustation, infection, migration, and patient discomfort. Ongoing attempts to create more inert stent with sophisticated novel designs are expected to improve current MS efficiency. MSs will play a major role in the future as a routine management of a variety of ureteral pathologies. PMID:21369375

  5. Biliary stent migration presenting with leg pain

    PubMed Central

    O'Connor, Ryan; Agrawal, Satyanisth; Aoun, Elie; Kulkarni, Abhijit

    2012-01-01

    Although the therapeutic benefits of endoscopic retrograde cholangiopancreatography (ERCP) usually outweigh the risks, there can be rare complications, including stent migration leading to perforation, intestinal obstruction or penetration. An 87-year-old woman presented with symptomatic choledocholithiasis. Two previous endoscopic attempts at stone removal were unsuccessful. On repeat ERCP at our institution, multiple large stones were removed, but complete duct clearance could not be achieved. A plastic biliary stent was placed with plans to reattempt in 6 weeks. Postoperatively, she had mild back pain radiating into her right leg that gradually worsened to the point where she was unable to ambulate. An abdominal CT scan showed the distal aspect of the biliary stent extending through the wall of the duodenum with the tip positioned within the right psoas muscle. The stent was successfully removed via a rat-toothed forceps. Our case illustrates an extremely rare complication of biliary stent placement. PMID:23162034

  6. Plastic Biliary Stent Migration During Multiple Stents Placement and Successful Endoscopic Removal Using Intra-Stent Balloon Inflation Technique: A Case Report and Literature Review.

    PubMed

    Calcara, Calcedonio; Broglia, Laura; Comi, Giovanni; Balzarini, Marco

    2016-02-05

    Late migration of a plastic biliary stent after endoscopic placement is a well known complication, but there is little information regarding migration of a plastic stent during multiple stents placement. A white man was hospitalized for severe jaundice due to neoplastic hilar stenosis. Surgical eligibility appeared unclear on admission and endoscopy was carried out, but the first stent migrated proximally at the time of second stent insertion. After failed attempts with various devices, the migrated stent was removed successfully through cannulation with a dilation balloon. The migration of a plastic biliary stent during multiple stents placement is a possible complication. In this context, extraction can be very complicated. In our patient, cannulation of a stent with a dilation balloon was the only effective method.

  7. Balloon-expandable Metallic Stents for Airway Diseases.

    PubMed

    Ohki, Takashi; Sugimoto, Seiichiro; Kurosaki, Takeshi; Otani, Shinji; Miyoshi, Kentaroh; Yamane, Masaomi; Miyoshi, Shinichiro; Oto, Takahiro

    2016-10-01

    Stent placement is an essential treatment for airway diseases. Although self-expandable metallic stents and silicone stents are commonly applied for the treatment of airway diseases, these stents are unsuitable for the treatment of small airway diseases encountered in pediatric patients and lung transplant recipients with airway complications. Currently, only vascular balloon-expandable metallic stents are available for the treatment of small airway diseases; however, little research has been conducted on the use of these stents in this field. We have launched a prospective feasibility study to clarify the safety and efficacy of balloon-expandable metallic stents for the treatment of airway diseases.

  8. Upper Gastrointestinal Stent Insertion in Malignant and Benign Disorders

    PubMed Central

    Kang, Hyoun Woo

    2015-01-01

    Upper gastrointestinal (GI) stents are increasingly being used to manage upper GI obstructions. Initially developed for palliative treatment of esophageal cancer, upper GI stents now play an emerging role in benign strictures of the upper GI tract. Because recurrent obstruction and stent-related complications are common, new modifications of stents have been implemented. Self-expandable metal stents (SEMS) have replaced older plastic stents. In addition, newly designed SEMS have been developed to prevent complications. This review provides an overview of the various types, indications, methods, complications, and clinical outcomes of upper GI stents in a number of malignant and benign disorders dividing the esophagus and gastroduodenum. PMID:26064817

  9. Call for standards in technical documentation of intracoronary stents.

    PubMed

    Lanzer, Peter; Gijsen, Frank J H; Topoleski, L D Timmie; Holzapfel, Gerhard A

    2010-01-01

    At present, the product information of intracoronary stents provided by the industry contains only limited technical data restricting judgments on the in vivo performance of individual products. Available experimental and clinical evidence suggests that interventional target sites display highly heterogeneous biomechanical behavior needed to be matched by specific stent and stent delivery system characteristics. To allow individualized stent-lesion matching, both, understanding of biomechanical properties of the atherosclerotic coronary artery lesions and expert knowledge of the intracoronary stent systems, are required. Here, the authors review some of the initial data on mechanical properties of coronary artery lesions potentially relevant to stenting and suggest standards for technical documentation of intracoronary stents.

  10. Self-expandable metal stents in malignant biliary obstruction.

    PubMed

    Jaganmohan, Sathya; Lee, Jeffrey H

    2012-02-01

    Malignant biliary obstruction can be due to direct tumor infiltration, extrinsic compression, adjacent inflammation, desmoplastic reaction from tumors or, more commonly, a combination of the above factors. Pancreatic cancer is the most common cause of malignant biliary obstruction, and jaundice occurs in 70-90% of the patients during the course of the disease. Compared with the uncovered metal stents, covered metal stents have longer patency and a lower rate of tumor ingrowth, but have a higher rate of stent migration. To combat the occlusion and provide an antitumor effect, drug-eluting stents were developed. A duodenal stricture complicates biliary stent placement in 10-20% of patients with distal biliary obstruction due to pancreatic cancer. When both strictures are considered, a biliary stent can be placed either preceding or following duodenal stent placement. Complications of self-expandable metal stents include stent occlusion, stent migration, cholecystitis and pancreatitis.

  11. Biliary stenting: indications, choice of stents and results: European Society of Gastrointestinal Endoscopy (ESGE) clinical guideline.

    PubMed

    Dumonceau, J-M; Tringali, A; Blero, D; Devière, J; Laugiers, R; Heresbach, D; Costamagna, G

    2012-03-01

    This article is part of a combined publication that expresses the current view of the European Society of Gastrointestinal Endoscopy about endoscopic biliary stenting. The present Clinical Guideline describes short-term and long-term results of biliary stenting depending on indications and stent models; it makes recommendations on when, how, and with which stent to perform biliary drainage in most common clinical settings, including in patients with a potentially resectable malignant biliary obstruction and in those who require palliative drainage of common bile duct or hilar strictures. Treatment of benign conditions (strictures related to chronic pancreatitis, liver transplantation, or cholecystectomy, and leaks and failed biliary stone extraction) and management of complications (including stent revision) are also discussed. A two-page executive summary of evidence statements and recommendations is provided. A separate Technology Review describes the models of biliary stents available and the stenting techniques, including advanced techniques such as insertion of multiple plastic stents, drainage of hilar strictures, retrieval of migrated stents and combined stenting in malignant biliary and duodenal obstructions.The target readership for the Clinical Guideline mostly includes digestive endoscopists, gastroenterologists, oncologists, radiologists, internists, and surgeons while the Technology Review should be most useful to endoscopists who perform biliary drainage.

  12. Hybrid stent device of flow-diverting effect and stent-assisted coil embolization formed by fractal structure.

    PubMed

    Kojima, Masahiro; Irie, Keiko; Masunaga, Kouhei; Sakai, Yasuhiko; Nakajima, Masahiro; Takeuchi, Masaru; Fukuda, Toshio; Arai, Fumihito; Negoro, Makoto

    2016-05-01

    This paper presents a novel hybrid medical stent device. This hybrid stent device formed by fractal mesh structures provides a flow-diverting effect and stent-assisted coil embolization. Flow-diverter stents decrease blood flow into an aneurysm to prevent its rupture. In general, the mesh size of a flow-diverter stent needs to be small enough to prevent blood flow into the aneurysm. Conventional flow-diverter stents are not available for stent-assisted coil embolization, which is an effective method for aneurysm occlusion, because the mesh size is too small to insert a micro-catheter for coil embolization. The proposed hybrid stent device is capable of stent-assisted coil embolization while simultaneously providing a flow-diverting effect. The fractal stent device is composed of mesh structures with fine and rough mesh areas. The rough mesh area can be used to insert a micro-catheter for stent-assisted coil embolization. Flow-diverting effects of two fractal stent designs were composed to three commercially available stent designs. Flow-diverting effects were analyzed using computational fluid dynamics (CFD) analysis and particle image velocimetry (PIV) experiment. Based on the CFD and PIV results, the fractal stent devices reduce the flow velocity inside an aneurism just as much as the commercially available flow-diverting stents while allowing stent-assisted coil embolization.

  13. Late Stent Expansion and Neointimal Proliferation of Oversized Nitinol Stents in Peripheral Arteries

    SciTech Connect

    Zhao, Hugh Q. Nikanorov, Alexander; Virmani, Renu; Jones, Russell; Pacheco, Erica; Schwartz, Lewis B.

    2009-07-15

    For peripheral endovascular intervention, self-expanding (SE) stents are commonly oversized in relation to target arteries to assure optimal wall apposition and prevent migration. However, the consequences of oversizing have not been well studied. The purpose of this study was to examine the effects of SE stent oversizing (OS) with respect to the kinetics of late stent expansion and the long-term histological effects of OS. Pairs of overlapped 8 x 28-mm Nitinol SE stents were implanted into the iliofemoral arteries of 14 Yucatan swine. Due to variations in target artery size, the stent-to-artery ratio ranged from 1.2:1 to 1.9:1. Lumen and stent diameters were assessed by quantitative angiography at the time of implantation. Following angiographic assessment at 6 months, stented arteries were perfusion-fixed, sectioned, and stained for histological analysis. Immediately following implantation, the stents were found to be expanded to a range of 4.7-7.1 mm, largely conforming to the diameter of the recipient target artery. The stents continued to expand over time, however, and all stents had enlarged to nearly their 8-mm nominal diameter by 6 months. The histological effects of OS were profound, with marked increases in injury and luminal area stenosis, including a statistically significant linear correlation between stent-to-artery ratio and area stenosis. In this experimental model of peripheral endovascular intervention, oversized Nitinol SE stents are constrained by their target artery diameter upon implantation but expand to their nominal diameter within 6 months. Severe OS (stent-to-artery ratio >1.4:1) results in a profound long-term histological response including exuberant neointimal proliferation and luminal stenosis.

  14. In-Stent Stenosis of Stent Assisted Endovascular Treatment on Intracranial Complex Aneurysms

    PubMed Central

    Yoon, Kyeong-Wook

    2010-01-01

    Objective To introduce the frequency and segment analysis of in-stent stenosis for intracranial stent assisted endovascular treatment on complex aneurysms. Methods A retrospective study was performed in 158 patients who had intracranial complex aneurysms and were treated by endovascular stent application with or without coil embolization. Of these, 102 patients were evaluated with catheter based angiography after 6, 12, and 18 months. Aneurysm location, using stent, time to stenosis, stenosis rate and narrowing segment were analyzed. Results Among follow-up cerebral angiography done in 102 patients, 8 patients (7.8%) were shown an in-stent stenosis. Two patients have unruptured aneurysm and six patients have ruptured one. Number of Neuroform stents were 7 cases (7.5%) and Enterprise stent in 1 case (11.1%). Six patients demonstrated in-stent stenosis at 6 months after stent application and remaining two patients were shown at 12 months, 18 months, respectively. Conclusion In-stent stenosis can be confronted after intracranial stent deployment. In our study, no patient showed symptomatic stenosis and there were no patients who required to further treatment except continuing antiplatets medication. In-stent stenosis has been known to be very few when they are placed into the non-pathologic parent artery during the complex aneurysm treatment, but the authors found that it was apt to happen on follow up angiography. Although the related symptom was not seen in our cases, the luminal narrowing at the stented area may result the untoward hemodynamic event in the specific condition. PMID:21430973

  15. Self-expandable metallic stents vs. plastic stents for endoscopic biliary drainage in hepatocellular carcinoma.

    PubMed

    Chung, Kwang Hyun; Lee, Sang Hyub; Park, Jin Myung; Lee, Jae Min; Ahn, Dong-Won; Ryu, Ji Kon; Kim, Yong-Tae

    2015-06-01

    The patency of self-expandable metallic stents (SEMS) is known to be better than plastic stents in the palliation of malignant biliary obstruction. However, data are scarce for obstructive jaundice caused by hepatocellular carcinoma (HCC). This study aimed to compare SEMSs and plastic stents for the palliation of obstructive jaundice in unresectable HCC. A total of 96 patients who underwent endoscopic retrograde biliary drainage with SEMSs or plastic stents were included in this retrospective analysis. The rate of successful biliary drainage, adverse events, stent patency duration, and patient survival were compared between the SEMS (n = 36) and plastic stent (n = 60) groups. The rate of successful biliary drainage was similar between the SEMS and plastic stent groups (25/36 [69.4 %] vs. 39/60 [65.0 %]; P = 0.655). Adverse events occurred in 6 patients (16.7 %) in the SEMS group and 13 patients (21.7 %) in the plastic stent group (P = 0.552). The median patency duration was also similar between the two groups (60 vs. 68 days; P = 0.396). The median patient survival was longer in the plastic stent group than in the SEMS group (123 vs. 48 days; P = 0.005). SEMSs were not superior to plastic stents for the palliation of malignant biliary obstruction in HCC with regard to successful drainage, stent patency, and adverse events. Patient survival was better in the plastic stent group. Given the lower cost, plastic stents could be a favorable option for malignant biliary obstruction caused by HCC. © Georg Thieme Verlag KG Stuttgart · New York.

  16. Fluoroscopy Guided Transurethral Placement of Ureteral Metallic Stents

    PubMed Central

    Myung Gyu, Song; Seo, Tae Seok; Park, Cheol Min; Choi, Jae Woong; Lee, Jong Mee; Park, Yang Shin

    2015-01-01

    Ureteral stent exchange is usually performed under both fluoroscopic and cystoscopic guidance. We experienced two cases with retrograde placement of metallic ureteral stent via urethra under fluoroscopic guidance. When patients with double-J ureteral stent (DJUS)have symptom and want to change DJUS to metallic stent, fluoroscopic guided transurethral placement of ureteral metallic stent is a good option as alternative of cystoscopic procedure or percutaneous procedure through percutaneous nephrostomy tract. PMID:26557281

  17. MR safety and imaging of neuroform stents at 3T.

    PubMed

    Nehra, Arvind; Moran, Christopher J; Cross, Dewitte T; Derdeyn, Colin P

    2004-10-01

    The Neuroform stent is a self-expanding nitinol stent designed for use in wide-necked intracranial aneurysms. Heating and imaging artifacts were evaluated by using a porcine carotid artery aneurysm model in a 3T MR system. A suspended Neuroform stent was tested for deflection. No heating was measured, and no evidence of deflection of the stent was found. Imaging artifacts were minimal. MR imaging in patients with Neuroform stent-treated aneurysms is safe and feasible.

  18. Stents for colorectal obstruction: Past, present, and future

    PubMed Central

    Kim, Eui Joo; Kim, Yoon Jae

    2016-01-01

    Since the development of uncovered self-expanding metal stents (SEMS) in the 1990s, endoscopic stents have evolved dramatically. Application of new materials and new designs has expanded the indications for enteral SEMS. At present, enteral stents are considered the first-line modality for palliative care, and numerous types of enteral stents are under development for extended clinical usage, beyond a merely palliative purpose. Herein, we will discuss the current status and the future development of lower enteral stents. PMID:26811630

  19. Headache after carotid artery stenting.

    PubMed

    Suller Marti, A; Bellosta Diago, E; Velázquez Benito, A; Tejero Juste, C; Santos Lasaosa, S

    2017-04-18

    Headache after carotid artery stenting is a headache with onset during the procedure or in the first few hours after it, and where there is no evidence to suggest a complication of that procedure. The purpose of this study is to describe the main features of these headaches based on our clinical experience. Observational prospective study of a sample of patients undergoing carotid artery stenting at Hospital Clínico Universitario Lozano Blesa, in Zaragoza, Spain. We recorded sociodemographic characteristics, cardiovascular risk factors, carotid artery disease, and history of primary headache; data were gathered using structured interviews completed before and 24hours after the procedure. We included 56 patients (mean age 67±9.52 years); 84% were men. Twelve patients (21.4%) experienced headache, 83.3% of whom were men; mean age was 60.58±9.31 years. Headache appeared within the first 6hours in 7 patients (58.4%) and during the procedure in 4 (33.3%). Pain lasted less than 10minutes in 4 patients (33.3%) and between 10 and 120minutes in 5 (41.7%). Headache affected the frontotemporal area in 7 patients (58.3%); 7 patients (58.3%) described pain as unilateral. It was oppressive in 8 patients (66.7%) and of moderate intensity in 6 (50%). Nine patients (75%) required no analgesics. We found no statistically significant associations with any of the variables except for age (P=.007; t test). In our sample, headache after carotid artery stenting was mild to moderate in intensity, unilateral, oppressive, and short-lasting. Further studies are necessary to gain a deeper knowledge of its characteristics and associated risk factors. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. Stent graft implantation in an aortic pseudoaneurysm associated with a fractured Cheatham-Platinum stent in aortic coarctation.

    PubMed

    Kuhelj, Dimitrij; Berden, Pavel; Podnar, Tomaž

    2016-03-01

    We report a case of aortic pseudoaneurysm associated with a fractured bare Cheatham-Platinum stent following stenting for aortic coarctation. These complications were recognised 6 years after the implantation procedure and were successfully managed by percutaneous stent graft implantation. Staged approach for stent dilatation might prevent development of aortic pseudoaneurysms. In addition, careful follow-up is warranted after stenting for aortic coarctation, particularly in patients with recognised aortic wall injury.

  1. Degradation Model of Bioabsorbable Cardiovascular Stents

    PubMed Central

    Luo, Qiyi; Liu, Xiangkun; Li, Zhonghua; Huang, Chubo; Zhang, Wen; Meng, Juan; Chang, Zhaohua; Hua, Zezhao

    2014-01-01

    This study established a numerical model to investigate the degradation mechanism and behavior of bioabsorbable cardiovascular stents. In order to generate the constitutive degradation material model, the degradation characteristics were characterized with user-defined field variables. The radial strength bench test and analysis were used to verify the material model. In order to validate the numerical degradation model, in vitro bench test and in vivo implantation studies were conducted under physiological and normal conditions. The results showed that six months of degradation had not influenced the thermodynamic properties and mechanical integrity of the stent while the molecular weight of the stents implanted in the in vivo and in vitro models had decreased to 61.8% and 68.5% respectively after six month's implantation. It was also found that the degradation rate, critical locations and changes in diameter of the stents in the numerical model were in good consistency in both in vivo and in vitro studies. It implies that the numerical degradation model could provide useful physical insights and prediction of the stent degradation behavior and evaluate, to some extent, the in-vivo performance of the stent. This model could eventually be used for design and optimization of bioabsorbable stent. PMID:25365310

  2. Stent Placement on Fresh Venous Thrombosis

    SciTech Connect

    Vorwerk, Dierk; Guenther, Rolf W.; Schuermann, Karl

    1997-09-15

    Purpose: To report on the efficacy of fixing fresh venous thrombus to the venous wall by stent placement. Methods: Seven patients underwent stenting to treat acute venous thrombosis. In two patients, the hemodialysis fistula was thrombosed with the thrombus extending into the brachial veins. In three patients, the hemodialysis fistula was patent but massive swelling of the ipsilateral arm was caused by proximal venous thrombosis. Two patients presented with iliac venous thrombosis within stented pelvic veins. Stent placement was preceded by other mechanical thrombectomy methods in all cases. Results: Attachment of thrombus to the venous wall was successful in all cases treated. Acute rethrombosis did not occur. Follow-up patency in dialysis patients was 7.2 {+-} 2.1 months. One patient had rethrombosis of the dialysis graft 3 months after primary treatment. Three patients developed restenosis within a mean period of 7.7 months. One shunt remained patent for 10 months with no event of reobstruction during follow-up. In both patients with iliac stent placement, the vein remained patent over a follow-up period of 8 and 12 months respectively. Conclusion: Stenting fresh venous thrombus can achieve immediate venous patency. It may be used as an alternative approach when all other percutaneous methods fail. Frequent restenosis within stented veins limits its use to very selected cases.

  3. Vascular pathology of drug-eluting stents.

    PubMed

    Nakazawa, Gaku; Finn, Aloke V; Virmani, Renu

    2007-06-01

    Polymer-based sirolimus- (Cypher) and paclitaxel-eluting stents (Taxus), so-called drug-eluting stents (DES), have become the treatment of choice for patients with symptomatic coronary artery disease undergoing percutaneous coronary revascularization (PCI). While these stents have reduced rates of restenosis and late lumen loss compared to bare-metal stents (BMS), late thrombosis, a life-threatening complication of this technology, has emerged as a major concern. Our understanding of the pathophysiology of late DES thrombosis is derived from animal and human pathologic samples taken after implantation of these devices. These data indicate that the DES cause substantial impairment in arterial healing characterized by lack of complete reendothelialization and persistence of fibrin when compared to BMS. This so-called delayed healing is "identified as" the primary substrate of an underlying cause of late DES thrombosis at autopsy. Several additional risk factors for late stent thrombosis include penetration of necrotic core, malapposition, overlapping stent placement, excessive stent length, and bifurcation lesions. These represent additional barriers to healing and should be avoided if DES are to be used in order to minimize the late thrombotic risks of these devices. Since the time course of complete healing with DES is unknown, the optimal duration of antiplatelet treatment remains to be determined.

  4. Are Carotid Stent Fractures Clinically Significant?

    SciTech Connect

    Garcia-Toca, Manuel; Rodriguez, Heron E.; Naughton, Peter A.; Keeling, Aiofee; Phade, Sachin V.; Morasch, Mark D.; Kibbe, Melina R.; Eskandari, Mark K.

    2012-04-15

    Purpose: Late stent fatigue is a known complication after carotid artery stenting (CAS) for cervical carotid occlusive disease. The purpose of this study was to determine the prevalence and clinical significance of carotid stent fractures. Materials and Methods: A single-center retrospective review of 253 carotid bifurcation lesions treated with CAS and mechanical embolic protection from April 2001 to December 2009 was performed. Stent integrity was analyzed by two independent observers using multiplanar cervical plain radiographs with fractures classified into the following types: type I = single strut fracture; type II = multiple strut fractures; type III = transverse fracture; and type IV = transverse fracture with dislocation. Mean follow-up was 32 months. Results: Follow-up imaging was completed on 106 self-expanding nitinol stents (26 closed-cell and 80 open-cell stents). Eight fractures (7.5%) were detected (type I n = 1, type II n = 6, and type III n = 1). Seven fractures were found in open-cell stents (Precise n = 3, ViVEXX n = 2, and Acculink n = 2), and 1 fracture was found in a closed-cell stent (Xact n = 1) (p = 0.67). Only a previous history of external beam neck irradiation was associated with fractures (p = 0.048). No associated clinical sequelae were observed among the patients with fractures, and only 1 patient had an associated significant restenosis ({>=}80%) requiring reintervention. Conclusions: Late stent fatigue after CAS is an uncommon event and rarely clinically relevant. Although cell design does not appear to influence the occurrence of fractures, lesion characteristics may be associated risk factors.

  5. Targeting In-Stent-Stenosis with RGD- and CXCL1-Coated Mini-Stents in Mice

    PubMed Central

    Weinandy, Stefan; Schreiber, Fabian; Megens, Remco T. A.; Theelen, Wendy; Smeets, Ralf; Jockenhövel, Stefan; Gries, Thomas; Möller, Martin; Klee, Doris; Weber, Christian; Zernecke, Alma

    2016-01-01

    Atherosclerotic lesions that critically narrow the artery can necessitate an angioplasty and stent implantation. Long-term therapeutic effects, however, are limited by excessive arterial remodeling. We here employed a miniaturized nitinol-stent coated with star-shaped polyethylenglycole (star-PEG), and evaluated its bio-functionalization with RGD and CXCL1 for improving in-stent stenosis after implantation into carotid arteries of mice. Nitinol foils or stents (bare metal) were coated with star-PEG, and bio-functionalized with RGD, or RGD/CXCL1. Cell adhesion to star-PEG-coated nitinol foils was unaltered or reduced, whereas bio-functionalization with RGD but foremost RGD/CXCL1 increased adhesion of early angiogenic outgrowth cells (EOCs) and endothelial cells but not smooth muscle cells when compared with bare metal foils. Stimulation of cells with RGD/CXCL1 furthermore increased the proliferation of EOCs. In vivo, bio-functionalization with RGD/CXCL1 significantly reduced neointima formation and thrombus formation, and increased re-endothelialization in apoE-/- carotid arteries compared with bare-metal nitinol stents, star-PEG-coated stents, and stents bio-functionalized with RGD only. Bio-functionalization of star-PEG-coated nitinol-stents with RGD/CXCL1 reduced in-stent neointima formation. By supporting the adhesion and proliferation of endothelial progenitor cells, RGD/CXCL1 coating of stents may help to accelerate endothelial repair after stent implantation, and thus may harbor the potential to limit the complication of in-stent restenosis in clinical approaches. PMID:27192172

  6. Endovascular Techniques in Limb Salvage: Stents

    PubMed Central

    El-Sayed, Hosam F.

    2013-01-01

    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. PMID:23805339

  7. Trajectory surgical guide stent for implant placement.

    PubMed

    Adrian, E D; Ivanhoe, J R; Krantz, W A

    1992-05-01

    This article describes a new implant placement surgical guide that gives both implant location and trajectory to the surgeon. Radiopaque markers are placed on diagnostic dentures and a lateral cephalometric radiograph is made that shows the osseous anatomy at the symphysis and the anterior tooth location. The ideal implant location and trajectory data are transferred to a surgical stent that programs the angle and location of the fixtures at time of surgery. The stent has the additional benefit of acting as an occlusion rim, a mouth prop, and tongue retractor. Use of this stent has resulted in consistently programming the placement of implant fixtures that are prosthodontically ideal.

  8. Delivery of stents to target lesions: techniques of intraoperative stent implantation and intraoperative angiograms.

    PubMed

    Ing, F F

    2005-01-01

    Mullins et al. [6] reported the first use of stent implantation to treat stenotic branch pulmonary arteries in 1988. In the early to mid-1990s, numerous reports confirmed its safety and efficacy, but there were limited stent and balloon designs and stent implantations were performed using relatively large delivery systems (10- to 12-Fr sheaths) [7, 8]. The general accepted patient size was limited to those weighing 12 kg or greater. Intraoperative stent implantation for branch pulmonary artery stenosis was reported in the early to mid-1990s [1-3, 5, 9]. Indications in these early reports included small patient size or difficult anatomy or patients who had additional cardiac lesions and needed surgery independent of the branch stenosis. The idea was to take advantage of the open-heart exposure provided in the operating room to permit direct access to the stenotic segment. Hence, all intraoperative stent implants were performed under direct visualization on bypass. There were no discussions on advantages over the routine percutaneous approach. Currently, with advances in stent and balloon technology as well as increased operator experience, many of those reported cases probably would have undergone cardiac catheterization for a percutaneous stent implant rather than open-heart surgery. The purpose of this report is to review the current indications, advantages, and disadvantages of intraoperative stent implantation as well as to discuss the techniques that are helpful to optimize intraoperative stent positioning. The role and advantages of intraoperative angiography will also be presented.

  9. Manual Replacement of Double J Stent Without Fluoroscopy (Double j stent replacement).

    PubMed

    Kose, Osman; Gorgel, Sacit Nuri; Ozbir, Sait; Yenigurbuz, Sekan; Kara, Cengiz

    2015-02-01

    It is not always possible to replace a ureteric stent with a new one due to the fact that tumoral effect increases in ureter with time. We present our experience of manual replacement of double J stent without fluoroscopy. The data from 23 female patients who underwent double J stent replacement with a total of 110 times was retrospectively analyzed. The steps of technique are as follows: take out distal end of the double J stent through urethra to external urethral meatus cystoscopically, insert a 0.035-inch guide wire through double J stent to the renal pelvis or intra pelvicaliceal system, take out old double J stent over guide wire, slide new stent over guide wire and at external meatus level take out guide wire while gently sliding distal end of double J stent over guide wire into urethra. The mean age was 58.39 ± 9.21 years. Cervical, endometrial, and ovarian cancer were diagnosed in 16, 4, and 3 patients respectively. The mean follow-up and indwelling period were 13.8 ± 5.2, 3.8 ± 0.6 months, respectively. Increased pelvicaliceal dilatation, serum creatinine level, or renal parenchymal loss was not observed. Replacement of double J stents with this technique is easy and can be used successfully in distal ureteral obstructions.

  10. Stent overlapping and geometric curvature influence the structural integrity and surface characteristics of coronary nitinol stents.

    PubMed

    Kapnisis, Konstantinos K; Halwani, Dina O; Brott, Brigitta C; Anderson, Peter G; Lemons, Jack E; Anayiotos, Andreas S

    2013-04-01

    Preliminary studies have revealed that some stents undergo corrosion and fatigue-induced fracture in vivo, with significant release of metallic ions into surrounding tissues. A direct link between corrosion and in-stent restenosis has not been clearly established; nonetheless in vitro studies have shown that relatively high concentrations of heavy metal ions can stimulate both inflammatory and fibrotic reactions, which are the main steps in the process of restenosis. To isolate the mechanical effects from the local biochemical effects, accelerated biomechanical testing was performed on single and overlapping Nickel-Titanium (NiTi) stents subjected to various degrees of curvature. Post testing, stents were evaluated using Scanning Electron Microscopy (SEM) to identify the type of surface alterations. Fretting wear was observed in overlapping cases, in both straight and curved configurations. Stent strut fractures occurred in the presence of geometric curvature. Fretting wear and fatigue fractures observed on stents following mechanical simulation were similar to those from previously reported human stent explants. It has been shown that biomechanical factors such as arterial curvature combined with stent overlapping enhance the incidence and degree of wear and fatigue fracture when compared to single stents in a straight tube configuration.

  11. Treatment of Post-Stent Gastroesophageal Reflux by Anti-Reflux Z-Stent

    SciTech Connect

    Davies, Roger Philip; Kew, Jacqueline; Byrne, Peter D.

    2000-11-15

    Severe symptoms of heartburn and retrosternal pain consistent with gastro-esophageal reflux (GER) developed in a patient following placement of a conventional self-expanding 16-24-mm-diameter x 12-cm-long esophageal stent across the gastroesophageal junction to treat an obstructing esophageal carcinoma. A second 18-mm-diameter x 10-cm-long esophageal stent with anti-reflux valve was deployed coaxially and reduced symptomatic GER immediately. Improvement was sustained at 4-month follow-up. An anti-reflux stent can be successfully used to treat significant symptomatic GER after conventional stenting.

  12. Forgotten CBD stent (102 months) with stone-stent complex: A case report.

    PubMed

    Barai, Varsha; Hedawoo, Jagadish; Changole, Sanjay

    2017-01-01

    Choledocholithiasis is presence of stone in Common bile duct (CBD) which can be treated by endoscopy or surgery [1]. Retained foreign bodies like stents forms a nidus for stone formation resulting in pain, fever, jaundice. 60 years female patient admitted in surgery ward with features of cholangitis with computed tomography showing cholangitic abscess with dilated common bile duct and sludge around stent in situ. Stone was found at proximal end of stent during surgery. Stents may remain without complications or may migrate, and rarely form nidus for stone formation. If kept for long time they lead to bacterial proliferation, biofilm formation and precipitation of calcium bilirubinate presenting as fever, pain, jaundice. Stent-stone complex can be treated endoscopically and surgically [6,7]. As stent can cause stone formation, infection and other complications, timely removal of stent should advised. III-effects of stent in-situ should be explained, record should be maintained [8] and patient should be advised regular follow up and stent removal after 6 weeks. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. PulmoStent: In Vitro to In Vivo Evaluation of a Tissue Engineered Endobronchial Stent.

    PubMed

    Thiebes, Anja Lena; Kelly, Nicola; Sweeney, Caoimhe A; McGrath, Donnacha J; Clauser, Johanna; Kurtenbach, Kathrin; Gesche, Valentine N; Chen, Weiluan; Kok, Robbert Jan; Steinseifer, Ulrich; Bruzzi, Mark; O'Brien, Barry J; McHugh, Peter E; Jockenhoevel, Stefan; Cornelissen, Christian G

    2017-04-01

    Currently, there is no optimal treatment available for end stage tumour patients with airway stenosis. The PulmoStent concept aims on overcoming current hurdles in airway stenting by combining a nitinol stent with a nutrient-permeable membrane, which prevents tumour ingrowth. Respiratory epithelial cells can be seeded onto the cover to restore mucociliary clearance. In this study, a novel hand-braided dog bone stent was developed, covered with a polycarbonate urethane nonwoven and mechanically tested. Design and manufacturing of stent and cover were improved in an iterative process according to predefined requirements for permeability and mechanical properties and finally tested in a proof of concept animal study in sheep for up to 24 weeks. In each animal two stents were implanted, one of which was cell-seeded by endoscopic spraying in situ. We demonstrated the suitability of this membrane for our concept by glucose transport testing and in vitro culture of respiratory epithelial cells. In the animal study, no migration occurred in any of the twelve stents. There was only mild granulation tissue formation and tissue reaction; no severe mucus plugging was observed. Thus, the PulmoStent concept might be a step forward for palliative treatment of airway stenosis with a biohybrid stent device.

  14. Coronary aneurysm and stent fracture following stenting of a myocardial bridge.

    PubMed

    Lu, Hao; Ge, Lei; Ge, Junbo

    2016-01-01

    Myocardial bridge is the most common congenital coronary anomaly. We represent an extremely rare case of stent fracture combination with coronary aneurysm following stenting of a myocardial bridge. This 60-years-old male patient underwent coronary angiography in the local hospital four years ago. Coronary angiography revealed a myocardial bridge in the distal left anterior descending coronary artery (LAD). A 3.0 mm × 29 mm sirolimus eluting stent was deployed in the distal LAD. Three years later, repeat coronary angiography showed a large coronary aneurysm in the mid segment of the stent. The patient subsequently underwent coronary artery bypass grafting with left internal mammary artery (LIMA) to the distal segment of the LAD. But six months later, another coronary angiography showed a stent fracture in mid portion of the stent associated with a large coronary aneurysm, and the LIMA graft was totally occluded. A possible mechanism of stent fracture was long-standing and cyclic mechanical stress on the stent by myocardium. These forces over a period of time may lead to metal fatigue and eventually fracture. Based on the observation of fracture and aneurysm in this study, we recommend that myocardial bridge should not be treated with intracoronary stenting. © 2015 Wiley Periodicals, Inc.

  15. Paraffin processing of stented arteries using a postfixation dissolution of metallic and polymeric stents.

    PubMed

    Fishbein, Ilia; Welch, Tre; Guerrero, David T; Alferiev, Ivan S; Adamo, Richard F; Chorny, Michael; Gupte, Rohit K; Tang, Yanqing; Levy, Robert J

    Studying the morphology of the arterial response to endovascular stent implantation requires embedding the explanted stented artery in rigid materials such as poly(methyl methacrylate) to enable sectioning through both the in situ stent and the arterial wall, thus maintaining the proper anatomic relationships. This is a laborious, time-consuming process. Moreover, the technical quality of stained plastic sections is typically suboptimal and, in some cases, precludes immunohistochemical analysis. Here we describe a novel technique for dissolution of metallic and plastic stents that is compatible with subsequent embedding of "destented" arteries in paraffin, fine sectioning, major staining protocols, and immunohistochemistry.

  16. Endoscopic management of malignant biliary obstruction by means of covered metallic stents: primary stent placement vs. re-intervention.

    PubMed

    Kida, M; Miyazawa, S; Iwai, T; Ikeda, H; Takezawa, M; Kikuchi, H; Watanabe, M; Imaizumi, H; Koizumi, W

    2011-12-01

    Recent progress in chemotherapy has prolonged the survival of patients with malignant biliary strictures, leading to increased rates of stent occlusion. Occlusion of covered metallic stents now occurs in about half of all patients with malignant biliary strictures. The removal of metallic stents followed by placement of a second stent has been attempted, but outcomes remain controversial. The aim of the current study was to evaluate the effectiveness and safety of the primary placement and secondary placement (re-intervention) of covered metallic stents and to assess the feasibility and safety of stent removal. The study included 186 patients with unresectable malignant biliary strictures who underwent primary stent placement between October 2001 and March 2010.  Covered biliary self-expandable metal stents (SEMSs) were removed in 39 of these patients, and 36 underwent re-intervention. The patency times, occlusion rates of the first stent and re-intervention, success rates of stent removal, and complications were investigated. Covered SEMSs were placed in 186 patients. The median patency time of the first stent was 352 days. Stent occlusion occurred in 48.9 % of the patients and was mainly caused by debris or food residue (37 %), dislocation (19 %), and migration with hyperplasia (19 %). Stent removal was attempted in 50 patients and was successful without complication in 39 (78 %). Most of the patients in whom stent removal was unsuccessful had migration with hyperplasia. The median patency time of the second stent was 263 days. The stent patency time did not significantly differ between the first and the second stent. Covered SEMSs could be safely removed at the time of stent occlusion. Patency rates were similar for initial stent placement and re-intervention. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Degradation behavior of biodegradable Fe35Mn alloy stents.

    PubMed

    Sing, N B; Mostavan, A; Hamzah, E; Mantovani, D; Hermawan, H

    2015-04-01

    This article reports a degradation study that was done on stent prototypes made of biodegradable Fe35Mn alloy in a simulated human coronary arterial condition. The stent degradation was observed for a short-term period from 0.5 to 168 h, which simulates the early period of stenting procedure. Potentiodynamic polarization and electrochemical impedance spectroscopy were used to quantify degradation rate and surface property of the stents. Results showed that signs of degradation were visible on both crimped and expanded stents after 1 h of test, mostly located on the stent's curvatures. The degradation rate of stent was higher compared to that of the original alloy, indicating the surface altering effect of stent fabrication processing to degradation. A single oxide layer was formed and detected as a porous structure with capacitive behavior. Expanded stents exhibited lower polarization resistance compared to the nonexpanded ones, indicating the cold work effect of expansion procedure to degradation. © 2014 Wiley Periodicals, Inc.

  18. Stent-based percutaneous coronary interventions in small coronary arteries.

    PubMed

    Roguin, Ariel; Grenadier, Ehud

    2006-01-01

    A third to half of all percutaneous coronary interventions involve small diameter vessels of less than 3 mm. Small vessel size is a predictor of restenosis after balloon angioplasty, as well as after stent placement. Stents deployed in small arteries, have a higher metal-to-artery ratio; this may increase the risk of sub-acute thrombosis or restenosis. Various studies have shown that stent design, stent coating, and stent strut thickness may determine event-free survival. Dedicated stents for small vessels with less amount of metal, appropriate expansion to the vessel size with correct radial force and cells morphology, and less prothrombotic properties, may further improve the results of stenting in this setting (thinner struts, fewer cells, or loops per circumference). This review provides an update on the current status, review the major trials and define the clinical utility of small vessel stenting, particularly in the era of drug-eluting stents.

  19. Hemodynamic analysis of edge stenosis in peripheral artery stent grafts.

    PubMed

    Al-Hakim, R; Lee, E W; Kee, S T; Seals, K; Varghese, B; Chien, A; Quirk, M; McWilliams, J

    2017-10-01

    The purpose of this study was to characterize the hemodynamics of peripheral artery stent grafts to guide intelligent stent redesign. Two surgically explanted porcine arteries were mounted in an ex vivo system with subsequent deployment of an Xpert self-expanding nitinol stent or Viabahn stent graft. The arteries were casted with radiopaque resin, and the cast then scanned using micro-computed tomography at 8μm isotropic voxel resolution. The arterial lumen was segmented and a computational mesh grid surface generated. Computational fluid dynamics (CFD) analysis was subsequently performed using COMSOL Multiphysics 5.1. CFD analysis demonstrated low endothelial shear stress (ESS) involving 9.4 and 63.6% surface area of the central stent graft and bare metal stent, respectively. Recirculation zones were identified adjacent to the bare metal stent struts, while none were identified in the central stent graft. However, the stent graft demonstrated malapposition of the proximal stent graft edge with low velocity flow between the PTFE lining and arterial wall, which was associated with longitudinally and radially oriented recirculation zones and low ESS. Computational hemodynamic analysis demonstrates that peripheral artery stent grafts have a superior central hemodynamic profile compared to bare metal stents. Stents grafts, however, suffer from malapposition at the proximal stent edge which is likely a major contributor to edge stenosis. Copyright © 2017 Editions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  20. Wall shear stress distributions on stented patent ductus arteriosus

    NASA Astrophysics Data System (ADS)

    Kori, Mohamad Ikhwan; Jamalruhanordin, Fara Lyana; Taib, Ishkrizat; Mohammed, Akmal Nizam; Abdullah, Mohammad Kamil; Ariffin, Ahmad Mubarak Tajul; Osman, Kahar

    2017-04-01

    A formation of thrombosis due to hemodynamic conditions after the implantation of stent in patent ductus arteriosus (PDA) will derived the development of re-stenosis. The phenomenon of thrombosis formation is significantly related to the distribution of wall shear stress (WSS) on the arterial wall. Thus, the aims of this study is to investigate the distribution of WSS on the arterial wall after the insertion of stent. Three dimensional model of patent ductus arteriosus inserted with different types of commercial stent are modelled. Computational modelling is used to calculate the distributions of WSS on the arterial stented PDA. The hemodynamic parameters such as high WSS and WSSlow are considered in this study. The result shows that the stented PDA with Type III stent has better hemodynamic performance as compared to others stent. This model has the lowest distributions of WSSlow and also the WSS value more than 20 dyne/cm2. From the observed, the stented PDA with stent Type II showed the highest distributions area of WSS more than 20 dyne/cm2. This situation revealed that the high possibility of atherosclerosis to be developed. However, the highest distribution of WSSlow for stented PDA with stent Type II indicated that high possibility of thrombosis to be formed. In conclusion, the stented PDA model calculated with the lowest distributions of WSSlow and WSS value more than 20dyne/cm2 are considered to be performed well in stent hemodynamic performance as compared to other stents.

  1. Mechanical design of an intracranial stent for treating cerebral aneurysms.

    PubMed

    Shobayashi, Yasuhiro; Tanoue, Tetsuya; Tateshima, Satoshi; Tanishita, Kazuo

    2010-11-01

    Endovascular treatment of cerebral aneurysms using stents has advanced markedly in recent years. Mechanically, a cerebrovascular stent must be very flexible longitudinally and have low radial stiffness. However, no study has examined the stress distribution and deformation of cerebrovascular stents using the finite element method (FEM) and experiments. Stents can have open- and closed-cell structures, and open-cell stents are used clinically in the cerebrovasculature because of their high flexibility. However, the open-cell structure confers a risk of in-stent stenosis due to protrusion of stent struts into the normal parent artery. Therefore, a flexible stent with a closed-cell structure is required. To design a clinically useful, highly flexible, closed-cell stent, one must examine the mechanical properties of the closed-cell structure. In this study, we investigated the relationship between mesh patterns and the mechanical properties of closed-cell stents. Several mesh patterns were designed and their characteristics were studied using numerical simulation. The results showed that the bending stiffness of a closed-cell stent depends on the geometric configuration of the stent cell. It decreases when the stent cell is stretched in the circumferential direction. Mechanical flexibility equal to an open-cell structure was obtained in a closed-cell structure by varying the geometric configuration of the stent cell.

  2. Post-sialendoscopy ductoplasty by salivary duct stent placements.

    PubMed

    Su, Chin-Hui; Lee, Kuo-Sheng; Tseng, Te-Ming; Hung, Shih-Han

    2016-01-01

    With damage to a duct or papilla after sialendoscopy, a stent may be necessary to prevent re-stenosis and for maintaining the salivary duct open after complete sialendoscopy. However factors affecting outcomes and complications after stent placement remain unclear. This study aimed to report preliminary experiences in salivary duct stent placement after sialendoscopy. Data from 35 procedures in 33 patients who received sialendoscopy with salivary duct stent placements at Mackay Memorial Hospital between October 2013 and June 2014 were recorded and compared for clinical data, as well as procedural techniques, findings, and outcomes. In the 35 stent placement procedures, the hypospadias silastic stent tubes were used in 27 and the Fr. 5 pediatric feeding tubes were used in the remaining eight. When the hypospadias silastic stent tubes were used for stenting, the stent obstruction and irritation rates were higher compared to those who used the Fr. 5 pediatric feeding tube (100 vs. 0 % and 67 vs. 33 %, respectively). None of the stents secured by a 5-0 nylon suture were complicated by dislocation but when the stents were secured by 6-0 nylon sutures, the dislocation rate went as high as 47.4 %. The duration needed for salivary duct stent placement might be potentially shortened to only 2 weeks. If a salivary duct stent is intended to be placed for a certain period before its scheduled removal, a suture strength equivalent or stronger than the 5-0 nylon suture should be considered for stent fixation.

  3. Stent Fracture and Reocclusion After Placement of a Single Self-Expanding Stent in the Common Iliac Artery and Endovascular Treatment

    SciTech Connect

    Higashiura, Wataru Sakaguchi, Shoji; Morimoto, Kengo; Kichikawa, Kimihiko

    2008-09-15

    We present a case of fracture of a single self-expanding stent placed in the common iliac artery (CIA). An 80-year-old woman underwent placement of a self-expanding stent for CIA occlusion. Stent fracture and reocclusion were detected after 18 months. Successful revascularization was achieved using a stent-in-stent maneuver. The possibility of stent fracture with reocclusion should be considered following treatment with a single self-expanding stent for CIA occlusion.

  4. Stenting precision: "Image small, miss small".

    PubMed

    Goldstein, James A

    2016-09-01

    Stenting by angiography alone predisposes to geographic miss STEMI culprit lesions are most susceptible to Geographic Miss Direct coronary imaging assures procedural precision and perfection. © 2016 Wiley Periodicals, Inc.

  5. Coronary angioscopy before and after stent deployment

    NASA Astrophysics Data System (ADS)

    Denardo, Scott J.; Schatz, Richard A.; Rocha-Singh, Krishna J.; Wong, S. Chiu; Morris, Nancy A.; Strumpf, Robert K.; Heuser, Richard R.; Teirstein, Paul

    1993-09-01

    Coronary angioscopy was used in an attempt to visualize the internal architecture of cardiac vessels before and after deployment of Palmaz-Schatz stents in 50 patients. The vessel was successfully visualized in 48 (96%) of these patients. In 24 patients, angioscopy was performed both after preliminary balloon angioplasty and then again after stent deployment. In all 24 patients the diameter of the lumen appeared larger after stent deployment as compared to after balloon angioplasty. In 16 of these 24 patients a dissection was documented by angioscopy after balloon angioplasty. The dissection was absent after stent deployment in all 16 patients. In seven patients, thrombus that was not apparent by angiography was visualized by angioscopy. Moreover, in four patients, thrombus that was suggested by angiography could not be confirmed by angioscopy.

  6. [Numerical modeling of shape memory alloy vascular stent's self-expandable progress and "optimized grid" of stent].

    PubMed

    Xu, Qiang; Liu, Yulan; Wang, Biao; He, Jin

    2008-10-01

    Vascular stent is an important medical appliance for angiocardiopathy. Its key deformation process is the expandable progress of stent in the vessel. The important deformation behaviour corresponds to two mechanics targets: deformation and stress. This paper is devoted to the research and development of vascular stent with proprietary intellectual property rights. The design of NiTinol self-expandable stent is optimized by means of finite element software. ANSYS is used to build the finite element simulation model of vascular stent; the molding material is NiTinol shape memory alloy. To cope with the factors that affect the structure of stent, the shape of grid and so on, the self-expanding process of Nitinol stent is simulated through computer. By making a comparison between two kinds of stents with similar grid structure, we present a new concept of "Optimized Grid" of stent.

  7. Emerging Stent and Balloon Technologies in the Femoropopliteal Arteries

    PubMed Central

    Pastromas, Georgios; Katsanos, Konstantinos; Krokidis, Miltiadis; Karnabatidis, Dimitrios

    2014-01-01

    Endovascular procedures for the management of the superficial femoral (SFA) and popliteal artery disease are increasingly common. Over the past decade, several stent technologies have been established which may offer new options for improved clinical outcomes. This paper reviews the current evidence for SFA and popliteal artery angioplasty and stenting, with a focus on randomized trials and registries of nitinol self-expanding stents, drug-eluting stents, dug-coated balloons, and covered stent-grafts. We also highlight the limitations of the currently available data and the future routes in peripheral arterial disease (PAD) stent and balloon technology. PMID:24672355

  8. Functional Self-Expandable Metal Stents in Biliary Obstruction

    PubMed Central

    Kwon, Chang-Il; Ko, Kwang Hyun; Hahm, Ki Baik

    2013-01-01

    Biliary stents are widely used not only for palliative treatment of malignant biliary obstruction but also for benign biliary diseases. Each plastic stent or self-expandable metal stent (SEMS) has its own advantages, and a proper stent should be selected carefully for individual condition. To compensate and overcome several drawbacks of SEMS, functional self-expandable metal stent (FSEMS) has been developed with much progress so far. This article looks into the outcomes and defects of each stent type for benign biliary stricture and describes newly introduced FSEMSs according to their functional categories. PMID:24143314

  9. Biomimicry, vascular restenosis and coronary stents.

    PubMed

    Schwartz, R S; van der Giessen, W J; Holmes, D R

    1998-01-01

    Biomimicry is in its earliest stages and is being considered in the realm of tissue engineering. If arterial implants are to limit neointimal thickening, purely passive structures cannot succeed. Bioactivity must be present, either by pharmacologic intervention or by fabricating a 'living stent' that contains active cellular material. As tissue engineering evolves, useful solutions will emerge from applying this knowledge directly to vascular biologic problems resulting from angioplasty, stenting, and vascular prosthesis research.

  10. Residual stresses in coronary artery stents.

    PubMed

    Möller, D; Reimers, W; Pyzalla, A; Fischer, A

    2001-01-01

    In western industrial countries, coronary heart disease is the most common cause of death. The reason is a coronary sclerosis, which by the generation of plaques narrows the inner lumen of an artery and, thus, deteriorates the blood supply. This leads to symptoms like burning pain or increased pressure in the chest, and finally to an under supply and damage of the heart muscle. In order to keep those portions of arteries that are covered by a plaque open, the stent technique was developed in the 1980s and is increasingly used since about 13 years. These stents are usually made of wires or of a slotted tube and are of two kinds: self-expanding and balloon expanding. Both types are implanted after being mounted on a catheter and expanded in the desired position. Self-expanding stents make use of the elastic deformation, while the other group of stents are expanded by a balloon, which brings about a plastic deformation of certain regions of the stent structure. Thus, after implantation, parts of these stents undergo two steps of distinct plastic deformation. First during compression, which is necessary for the mounting procedure on the catheter (crimping), and second during expansion for implantation. In this article, the residual stresses generated during crimping and expansion are presented and discussed. These stresses are stored in the structure of a portion of a stent after implantation and are superimposed on those stresses generated by the more than 700 million cyclic heart beats during the patient's life. This work is a part of several interdisciplinary research projects by the authors in order to gain reliable fail-safe criteria for the static and cyclic mechanical properties of coronary stents.

  11. Stent graft for nephrologists: concerns and consensus.

    PubMed

    Salman, Loay; Asif, Arif

    2010-07-01

    The role of the stent graft is emerging in the management of arteriovenous dialysis access. Physicians are incorporating this device in the management of three distinct problems--vein-graft anastomotic stenosis, pseudoaneurysm formation, and cephalic arch stenosis--with varying degrees of success. Indeed, a recent randomized, controlled trial to evaluate the role of angioplasty plus stent graft versus angioplasty alone for the management of stenosis at the vein-graft anastomosis led to the approval of the stent graft by the Food and Drug Administration; however, several elements of the management of stenosis at the vein-graft anastomosis/cephalic arch as well as the repair of pseudoaneurysms by stent graft remain controversial. The situation is further complicated and warrants a cost-to-benefit ratio analysis when the added cost of the device is appended to the procedure. In contrast to the controversies, angioplasty-induced complete vascular rupture is one situation in which a stent graft is indicated beyond any doubt. With recent conditional Food and Drug Administration approval, it is anticipated that the use of stent grafts might increase in our patients. In this context, it is critically important that nephrologists be familiar with the current controversies and consensus that surround the use of stent grafts for dialysis access. Just as therapeutic interventions are analyzed in other disciplines within nephrology, these experts must appraise the use of this device for dialysis access. This report presents an up-to-date synopsis on the use of the stent graft that would assist renal physicians in requesting or rejecting the device for the optimal management of their patient's vascular access dysfunction.

  12. Stenting in Acute Lower Limb Arterial Occlusions

    SciTech Connect

    Raja, Jowad; Munneke, Graham; Morgan, Robert; Belli, Anna-Maria

    2008-07-15

    Management of critical limb ischemia of acute onset includes surgical embolectomy, bypass grafting, aspiration thrombectomy, thrombolysis, and mechanical thrombectomy followed by treatment of the underlying cause. We present our experience with the use of stents to treat acute embolic/thrombotic occlusions in one iliac and three femoropopliteal arteries. Although this is a small case series, excellent immediate and midterm results suggest that stenting of acute occlusions of the iliac, superficial femoral, and popliteal arteries is a safe and effective treatment option.

  13. Nasolacrimal Polyurethane Stent: Complications with CT Correlation

    SciTech Connect

    Pinto, Isabel T.; Paul, Laura; Grande, Carlos

    1998-11-15

    Purpose: To evaluate initial results in patients with epiphora secondary to obstruction of the nasolacrimal duct treated by placement of a polyurethane stent, and to discuss the technical problems and complications arising during the procedure, with visualization of the anatomy of the drainage apparatus using computed tomography (CT). Methods: We inserted 20 polyurethane Song stents under fluoroscopic guidance after dacryocystography in 19 patients with grade 3-4 epiphora caused by idiopathic obstruction of the nasolacrimal duct. CT scans were obtained following stent placement in all patients. Results: We focus on the technical problems and complications that arose during these procedures. During negotiation of the guidewire past the obstruction at the level of the junction of the duct with the lacrimal sac, the guidewire created a false passage in a posterior suborbital direction in two cases and towards the posterior midline in another. In all cases the guidewire was withdrawn and reinserted through the proper anatomic route without further difficulty or complications. In two cases the stent was improperly positioned wholly or partially outside the nasolacrimal system (one medially, one posteriorly). In one case the stent was removed and reinserted; in the other it remains in place and functional. CT was performed in all these cases to ensure proper anatomic alignment and determine what had gone wrong. The epiphora was completely resolved in 13 cases and partially relieved in four; there were three cases of stent obstruction. Epistaxis of short duration (1 hr) occurred in seven patients and headache in one. Conclusions: Treatment of epiphora with polyurethane stents is a technique that is well tolerated by patients and achieves a high success rate, yet problems in placement may be encountered. Though no major consequences for patients are involved, cognizance of such difficulties is important to avoid incorrect positioning of stents.

  14. Coronary stenting: A matter of revascularization

    PubMed Central

    Bonaventura, Aldo; Montecucco, Fabrizio; Liberale, Luca

    2017-01-01

    In the last few decades, the recommended treatment for coronary artery disease has been dramatically improved by percutaneous coronary intervention (PCI) and the use of balloon catheters, bare metal stents (BMSs), and drug-eluting stents (DESs). Catheter balloons were burdened by acute vessel occlusion or target-lesion re-stenosis. BMSs greatly reduced those problems holding up the vessel structure, but showed high rates of in-stent re-stenosis, which is characterized by neo-intimal hyperplasia and vessel remodeling leading to a re-narrowing of the vessel diameter. This challenge was overtaken by first-generation DESs, which reduced re-stenosis rates to nearly 5%, but demonstrated delayed arterial healing and risk for late in-stent thrombosis, with inflammatory cells playing a pivotal role. Finally, new-generation DESs, characterized by innovations in design, metal composition, surface polymers, and anti-proliferative drugs, finally reduced the risk for stent thrombosis and greatly improved revascularization outcomes. New advances include bioresorbable stents potentially changing the future of revascularization techniques as the concept bases upon the degradation of the stent scaffold to inert particles after its function expired, thus theoretically eliminating risks linked with both stent thrombosis and re-stenosis. Talking about DESs also dictates to consider dual antiplatelet therapy (DAPT), which is a fundamental moment in view of the good outcome duration, but also deals with bleeding complications. The better management of patients undergoing PCI should include the use of DESs and a DAPT finely tailored in consideration of the potentially developing bleeding risk in accordance with the indications from last updated guidelines. PMID:28400917

  15. Outcomes of the single-stent versus kissing-stents technique in asymmetric complex aortoiliac bifurcation lesions.

    PubMed

    Suh, Yongsung; Ko, Young-Guk; Shin, Dong-Ho; Kim, Jung-Sun; Kim, Byeong-Keuk; Choi, Donghoon; Hong, Myeong-Ki; Jang, Yangsoo

    2015-07-01

    This study investigated the outcomes of single-stent vs kissing-stents techniques in asymmetric complex aortoiliac bifurcation (ACAB) lesions. We retrospectively investigated 80 consecutive patients (69 males, 66.6 ± 8.7 years) treated with a single stent and 30 patients (26 males, 67.1 ± 7.7 years) treated with kissing stents for ACAB between January 2005 and December 2012 from a single-center cohort. A ACAB lesion was defined as a symptomatic unilateral common iliac artery stenosis (>50%) combined with intermediate stenosis (30%-50%) in the contralateral common iliac artery ostium. The primary end point was the primary patency of the ACAB. The baseline clinical characteristics did not differ significantly between the single-stent and the kissing-stents group. Technical success was achieved in all patients. The single-stent group required fewer stents (1.3 ± 0.5 vs 2.3 ± 0.8; P < .001) and less bilateral femoral access (55% vs 100%; P < .001). Two patients in the single-stent group (3%) required bailout kissing stents because of plaque shift to the contralateral side. The major complication rates were 8% in single-stent vs 13% in the kissing-stent group, which was similar (P = .399). At 3 years, the single-stent and kissing-stents group had similar rates of primary patency (89% vs 87%; P = .916) and target lesion revascularization-free survival (93% vs 87%; P = .462). The single-stent technique in ACAB was safe and showed midterm outcomes comparable with those of kissing stents. Considering the benefits, such as fewer stents, less bilateral femoral access, and the availability of contralateral access for future intervention, the single-stent technique may be an advantageous treatment option in ACAB. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  16. Research of Customized Aortic Stent Graft Manufacture

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Chen, Xin; Liu, Muhan

    2017-03-01

    Thoracic descending aorta diseases include aortic dissection and aortic aneurysm, of which the natural mortality rate is extremely high. At present, endovascular aneurysm repair (EVAR) has been widely used as an effective means for the treatment of descending aortic disease. Most of the existing coating stents are standard design, which are unable to meet the size or structure of different patients. As a result, failure of treatment would be caused by dimensional discrepancy between stent and vessels, which could lead to internal leakage or rupture of blood vessels. Therefore, based on rapid prototyping sacrificial core - coating forming (RPSC-CF), a customized aortic stent graft manufactured technique has been proposed in this study. The aortic stent graft consists of film and metallic stent, so polyether polyurethane (PU) and nickel-titanium (NiTi) shape memory alloy with good biocompatibility were chosen. To minimum film thickness without degrading performance, effect of different dip coating conditions on the thickness of film were studied. To make the NiTi alloy exhibit super-elasticity at body temperature (37°C), influence of different heat treatment conditions on austenite transformation temperature (Af) and mechanical properties were studied. The results show that the customized stent grafts could meet the demand of personalized therapy, and have good performance in blasting pressure and radial support force, laying the foundation for further animal experiment and clinical experiment.

  17. Role of Animal Models in Coronary Stenting.

    PubMed

    Iqbal, Javaid; Chamberlain, Janet; Francis, Sheila E; Gunn, Julian

    2016-02-01

    Coronary angioplasty initially employed balloon dilatation only. This technique revolutionized the treatment of coronary artery disease, although outcomes were compromised by acute vessel closure, late constrictive remodeling, and restenosis due to neointimal proliferation. These processes were studied in animal models, which contributed to understanding the biology of endovascular arterial injury. Coronary stents overcome acute recoil, with improvements in the design and metallurgy since then, leading to the development of drug-eluting stents and bioresorbable scaffolds. These devices now undergo computer modeling and benchtop and animal testing before evaluation in clinical trials. Animal models, including rabbit, sheep, dog and pig are available, all with individual benefits and limitations. In smaller mammals, such as mouse and rabbit, the target for stenting is generally the aorta; whereas in larger animals, such as the pig, it is generally the coronary artery. The pig coronary stenting model is a gold-standard for evaluating safety; but insights into biomechanical properties, the biology of stenting, and efficacy in controlling neointimal proliferation can also be gained. Intra-coronary imaging modalities such as intravascular ultrasound and optical coherence tomography allow precise serial evaluation in vivo, and recent developments in genetically modified animal models of atherosclerosis provide realistic test beds for future stents and scaffolds.

  18. Recent Advances in Drug Eluting Stents

    PubMed Central

    Puranik, Amey S.; Dawson, Eileen R.; Peppas, Nicholas A.

    2013-01-01

    One of the most common medical interventions to reopen an occluded vessel is the implantation of a coronary stent. While this method of treatment is effective initially, restenosis, or the re-narrowing of the artery frequently occurs largely due to neointimal hyperplasia of smooth muscle cells. Drug eluting stents were developed in order to provide local, site-specific, controlled release of drugs that can inhibit neointima formation. By implementing a controlled release delivery system it may be possible to control the time release of the pharmacological factors and thus be able to bypass some of the critical events associated with stent hyperplasia and prevent the need for subsequent intervention. However, since the advent of first-generation drug eluting stents, long-term adverse effects have raised concerns regarding their safety. These limitations in safety and efficacy have triggered considerable research in developing biodegradable stents and more potent drug delivery systems. In this review, we shed light on the current state-of-the-art in drug eluting stents, problems related to them and highlight some of the ongoing research in this area. PMID:23117022

  19. High single-session success rate of endoscopic bilateral stent-in-stent placement with modified large cell Niti-S stents for malignant hilar biliary obstruction.

    PubMed

    Kogure, Hirofumi; Isayama, Hiroyuki; Nakai, Yousuke; Tsujino, Takeshi; Matsubara, Saburo; Yashima, Yoko; Ito, Yukiko; Hamada, Tsuyoshi; Takahara, Naminatsu; Miyabayashi, Koji; Mizuno, Suguru; Mohri, Dai; Kawakubo, Kazumichi; Sasaki, Takashi; Yamamoto, Natsuyo; Hirano, Kenji; Sasahira, Naoki; Tada, Minoru; Koike, Kazuhiko

    2014-01-01

    Endoscopic bilateral self-expandable metallic stent (SEMS) placement in a stent-in-stent method for malignant hilar biliary obstruction is technically challenging. Technical difficulties in the initial placement and reinterventions for stent occlusion are disadvantages inherent to this stent-in-stent method. We previously reported the feasibility of Niti-S large cell D-type biliary stents (LCD). This multicenter prospective consecutive study evaluated the efficacy of bilateral SEMS placement using modified LCD with large and uniform cells, a slimmer delivery system and high radial force. From July 2010 to June 2011, 26 consecutive patients with unresectable malignant hilar biliary obstruction underwent endoscopic bilateral placement of modified LCD in a stent-in-stent method at three tertiary hospitals. Ten patients had gallbladder cancer, eight had cholangiocarcinoma, four had lymph node metastasis, two had intrahepatic cholangiocarcinoma, and two had liver metastasis. Single-session and final technical success rate was 96% and 100%, respectively. Functional success rate was 89%. Stent occlusion occurred in 11 patients (42%) because of sludge (n = 7) or tumor ingrowth (n = 4). Endoscopic bilateral reintervention was technically easy and successful: six patients had stent clearance by balloon sweeping and five had plastic stent placement. According to Kaplan-Meier analysis, median survival and stent patency were 220 days and 157 days, respectively. Modified LCD achieved a high technical success rate both in the initial stent-in-stent placement and in bilateral reinterventions in patients with malignant hilar biliary obstruction. © 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.

  20. Mechanical properties of various z-stent designs: an endovascular stent-grafting perspective.

    PubMed

    Bashar, Abul Hasan Muhammad; Kazui, Teruhisa; Washiyama, Naoki; Terada, Hitoshi; Yamashita, Katsushi; Haque, Mohammad E

    2003-08-01

    To comparatively assess the mechani-cal behavior of various clinically relevant Z-stent designs. A total of 16 Z-stents of original, biliary, spiral, and double-skirted designs (n=4 for each) were constructed using similar specifications for all. Stents were then evaluated for stiffness, snap opening force (SOF), flexibility, and displacement force using a novel tensiometer. Differences among the stents were determined using statistical methods. Stents explanted from dog aorta after a mean follow-up of 13 months were examined under a scanning electron microscope for surface defects. Forces required for about 50% reduction in diameter were 1.88 +/- 0.16 N, 3.81 +/- 0.21 N, 2.76 +/- 0.22 N, and 3.35 +/- 0.19 N for original, biliary, spiral, and skirted designs, respectively. Differences among the four designs were statistically significant at almost all points of measurement (P < 0.0001). Biliary and skirted designs showed higher SOF values in the early measurements. Stents explanted from dog aorta after a mean duration of 13 months showed no obvious corrosion or breakage in the wire struts. Significant differences exist among the various Z-stent designs in terms of their mechanical properties. Understanding them should help to select the appropriate stent for a given lesion. 316L stainless steel shows a favorable long-term tissue interaction.

  1. Disintegration of the Top Stent on Zenith Abdominal Aortic Stent-Grafts.

    PubMed

    Lindström, David; Wahlgren, Carl Magnus; Sonesson, Björn; Resch, Timothy

    2016-04-01

    To describe a heretofore unreported complication involving the Zenith Low Profile (LP) stent-graft. Two men, aged 75 and 67 years, respectively, underwent abdominal aortic aneurysm repair with a Zenith LP device. At 4 and 3 years, respectively, computed tomography angiography revealed separation of the proximal fixation stent from the stent-graft. In the first patient, there was stent-graft migration but no evidence of an endoleak; however, the aneurysm had grown. A fenestrated cuff was placed, sealing distally in the previous LP graft. The second patient had a type I endoleak. Open surgery was performed, and the main body of the graft was explanted. Postoperative examination of the device revealed that the fixation sutures on the suprarenal stent were still attached to the stent and had eroded through the graft material. Physicians should be aware of the potential for top stent separation from the Zenith LP stent-graft as a cause of endoleak and migration. © The Author(s) 2016.

  2. Nitinol Esophageal Stents: New Designs and Clinical Indications

    SciTech Connect

    Strecker, Ernst-Peter; Boos, Irene; Vetter, Sylvia; Strohm, Michael; Domschke, Sigurd

    1996-11-15

    Purpose: To evaluate the clinical use of covered and noncovered, knitted nitinol stents in patients presenting new stent indications. Methods: Self-expandable, knitted nitinol stents were implanted in four patients for treatment of dysphagia. In two patients who had malignant strictures and had esophago-respiratory fistulae and in one patient with an esophagocutaneous fistula, polytetrafluoroethylene (PTFE)-covered stents were implanted. One patient received a noncovered stent, but a retrograde approach through a percutaneous endoscopic gastrostomy (PEG) fistula had to be chosen for recanalization of an esophageal occlusion. Two patients received stents for treatment of benign strictures. Results: Recanalization of the stricture and stent implantation were performed under fluoroscopic control without any procedure-related morbidity or mortality. Dysphagia improved in all patients and the esophageal fistulae could be sealed off by covered stents. During a maximum follow-up of 18 months, there was no stent migration or esophageal perforation. Complications observed were stent stenosis due to food impaction (1/4) and benign stent stenosis (2/2). Most complications could be treated by the interventional radiologist. Conclusion: Self-expandable, covered Nitinol stents provide an option for the treatment of dysphagia combined with esophageal fistulae. In combination with interventional radiology techniques, even complex strictures are accessible. For benign strictures, the value of stent treatment has not yet been proven.

  3. Computational Study of Axial Fatigue for Peripheral Nitinol Stents

    NASA Astrophysics Data System (ADS)

    Meoli, Alessio; Dordoni, Elena; Petrini, Lorenza; Migliavacca, Francesco; Dubini, Gabriele; Pennati, Giancarlo

    2014-07-01

    Despite their success as primary treatment for vascular diseases, Nitinol peripheral stents are still affected by complications related to fatigue failure. Hip and knee movements during daily activities produce large and cyclic deformations of the superficial femoral artery, that concomitant to the effects of pulsatile blood pressure, may cause fatigue failure in the stent. Fatigue failure typically occurs in cases of very extended lesions, which often require the use of two or more overlapping stents. In this study, finite element models were used to study the fatigue behavior of Nitinol stents when subjected to cyclic axial compression in different conditions. A specific commercial Nitinol stent was chosen for the analysis and subjected to cyclic axial compression typical of the femoral vascular region. Three different configurations were investigated: stent alone, stent deployed in a tube, and two overlapping stents deployed in a tube. Results confirm that stent oversizing has an influence in determining both the mean and amplitude strains induced in the stent and plays an important role in determining the fatigue response of Nitinol stents. In case of overlapping stents, numerical results suggest higher amplitude strains concentrate in the region close to the overlapping portion where the abrupt change in stiffness causes higher cyclic compression. These findings help to explain the high incidence of stent fractures observed in various clinical trials located close to the overlapping portion.

  4. Novel biodegradable polydioxanone stents in a rabbit airway model.

    PubMed

    Novotny, Ladislav; Crha, Michal; Rauser, Petr; Hep, Ales; Misik, Jan; Necas, Alois; Vondrys, David

    2012-02-01

    This study was undertaken to evaluate safety and biocompatibility of a novel biodegradable polydioxanone stent in a rabbit tracheal model. Metallic and silicone stents represent standard therapeutic approaches for hollow organ stenosis, although complications have been reported repeatedly. Biodegradable stents could reduce the risks associated with this procedure while still achieving the purpose of maintaining lumen patency. A commercially available polydioxanone suture strand with a long safety record was used to manufacture the self-expanding stents. The polydioxanone stents were then implanted bronchoscopically and under fluoroscopic guidance into the tracheas of white rabbits (N = 25). Periodic clinical examination was performed. Histopathologic examination concluded the study for the 5 experimental groups at 3, 4, 5, 10, and 15 weeks after implantation. There were no unexpected deaths and no stent displacements during the study. The animals remained in good condition, without stent debris expectoration. Macroscopic examination revealed that the tracheal lumen stayed open. Histologic examination showed that tracheal damage score was highest 5 weeks after stenting, including in-stent necrosis of the epithelium. Stent degradation was complete with no remnants after 10 weeks, leaving the trachea completely healed at 15 weeks after implantation. This animal airway model has demonstrated acceptable safety and biocompatibility of this novel biodegradable polydioxanone stent. We suggest that polydioxanone stenting be used for further clinical studies for cases in which complete stent degradation after temporary airway treatment is desirable. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  5. Risk Factors for Migration, Fracture, and Dislocation of Pancreatic Stents

    PubMed Central

    Kawaguchi, Yoshiaki; Lin, Jung-Chun; Kawashima, Yohei; Maruno, Atsuko; Ito, Hiroyuki; Ogawa, Masami; Mine, Tetsuya

    2015-01-01

    Aim. To analyze the risk factors for pancreatic stent migration, dislocation, and fracture in chronic pancreatitis patients with pancreatic strictures. Materials and Methods. Endoscopic stent placements (total 386 times) were performed in 99 chronic pancreatitis patients with pancreatic duct stenosis at our institution between April 2006 and June 2014. We retrospectively examined the frequency of stent migration, dislocation, and fracture and analyzed the patient factors and stent factors. We also investigated the retrieval methods for migrated and fractured stents and their success rates. Results. The frequencies of stent migration, dislocation, and fracture were 1.5% (5/396), 0.8% (3/396), and 1.2% (4/396), respectively. No significant differences in the rates of migration, dislocation, or fracture were noted on the patient factors (etiology, cases undergoing endoscopic pancreatic sphincterotomy, location of pancreatic duct stenosis, existence of pancreatic stone, and approach from the main or minor papilla) and stent factors (duration of stent placement, numbers of stent placements, stent shape, diameter, and length). Stent retrieval was successful in all cases of migration. In cases of fractured stents, retrieval was successful in 2 of 4 cases. Conclusion. Stent migration, fracture, and dislocation are relatively rare, but possible complications. A good understanding of retrieval techniques is necessary. PMID:25945085

  6. Paclitaxel-eluting stents versus bare-metal stents in acute myocardial infarction.

    PubMed

    Stone, Gregg W; Lansky, Alexandra J; Pocock, Stuart J; Gersh, Bernard J; Dangas, George; Wong, S Chiu; Witzenbichler, Bernhard; Guagliumi, Giulio; Peruga, Jan Z; Brodie, Bruce R; Dudek, Dariusz; Möckel, Martin; Ochala, Andrzej; Kellock, Alison; Parise, Helen; Mehran, Roxana

    2009-05-07

    There is no consensus regarding the safety and efficacy of drug-eluting stents, as compared with bare-metal stents, in patients with ST-segment elevation myocardial infarction who are undergoing primary percutaneous coronary intervention (PCI). We randomly assigned, in a 3:1 ratio, 3006 patients presenting with ST-segment elevation myocardial infarction to receive paclitaxel-eluting stents (2257 patients) or otherwise identical bare-metal stents (749 patients). The two primary end points of the study were the 12-month rates of target-lesion revascularization for ischemia (analysis powered for superiority) and a composite safety outcome measure of death, reinfarction, stroke, or stent thrombosis (powered for noninferiority with a 3.0% margin). The major secondary end point was angiographic evidence of restenosis at 13 months. Patients who received paclitaxel-eluting stents, as compared with those who received bare-metal stents, had significantly lower 12-month rates of ischemia-driven target-lesion revascularization (4.5% vs. 7.5%; hazard ratio, 0.59; 95% confidence interval [CI], 0.43 to 0.83; P=0.002) and target-vessel revascularization (5.8% vs. 8.7%; hazard ratio, 0.65; 95% CI, 0.48 to 0.89; P=0.006), with noninferior rates of the composite safety end point (8.1% vs. 8.0%; hazard ratio, 1.02; 95% CI, 0.76 to 1.36; absolute difference, 0.1 percentage point; 95% CI, -2.1 to 2.4; P=0.01 for noninferiority; P=0.92 for superiority). Patients treated with paclitaxel-eluting stents and those treated with bare-metal stents had similar 12-month rates of death (3.5% and 3.5%, respectively; P=0.98) and stent thrombosis (3.2% and 3.4%, respectively; P=0.77). The 13-month rate of binary restenosis was significantly lower with paclitaxel-eluting stents than with bare-metal stents (10.0% vs. 22.9%; hazard ratio, 0.44; 95% CI, 0.33 to 0.57; P<0.001). In patients with ST-segment elevation myocardial infarction who were undergoing primary PCI, implantation of paclitaxel

  7. A review of the iStent® trabecular micro-bypass stent: safety and efficacy

    PubMed Central

    Wellik, Sarah R; Dale, Elizabeth A

    2015-01-01

    There is a significant demand for procedures that can effectively treat glaucoma with low risk and good visual outcomes. To fill this void, procedures termed “minimally invasive glaucoma surgery”, are gaining in popularity. This review will focus on the safety and efficacy of one such minimally invasive glaucoma surgery procedure, the trabecular micro-bypass stent. This stent is intended to lower intraocular pressure by directly cannulating Schlemm’s canal and thereby enhancing aqueous outflow. Recent randomized controlled trials and case series have demonstrated the micro-bypass stent to be a relatively safe procedure, with limited complications and no serious adverse sequelae. The most common complication across all studies was stent obstruction or malposition, which generally did not result in any adverse outcome in vision or pressure control. In addition, increased rates of hypotony, choroidal hemorrhage, or infection were not seen with the micro-bypass stent in comparison to cataract surgery alone. PMID:25931808

  8. Subacute Drug-Eluting Stent Thrombosis Caused by Stent Underexpansion: Evaluation by Optical Coherence Tomography

    PubMed Central

    Martín-Reyes, Roberto; Jiménez-Valero, Santiago; Navarro, Felipe; Moreno, Raúl

    2011-01-01

    We present the case report of a patient presenting with ST segment elevation myocardial infarction due to a subacute drug-eluting stent trombosis within the proximal segment of the left circumflex artery (LCX). Six days before a total chronic occlusion was treated at the mid segment of the LCX by overlapping two drug-eluting stents. Optical coherence tomography (OCT) was helpful to demonstrate stent underexpansion of the overlaping segment as the main mechanism of early stent thrombosis. This case is illustrative about the potential role of OCT to identify the mechanisms of ST and thus guiding the PCI procedure. Moreover, our case shows the capability of the Imagewire to cross a severe stenosis due to stent underexpansion that could not be crossed by the IVUS catheter. PMID:21423540

  9. Treatment of Secondary Stent-Graft Collapse After Endovascular Stent-Grafting for Iliac Artery Pseudoaneurysms

    SciTech Connect

    Clevert, D.-A. Stickel, M.; Steitz, H.-O.; Kopp, R.; Strautz, T.; Flach, P.; Johnson, T.; Jung, E.M.; Jauch, K.W.; Reiser, M.

    2007-02-15

    We report the case of a patient who developed an asymptomatic pseudoaneurysm in the left external iliac artery after transplant nephrectomy. The pseudoaneurysm most probably arose as a suture aneurysm from the external iliac artery after removal of the graft renal artery. Obviously we can not exclude the possibility it was a true aneurysm, although this seems much less likely. The pseudoaneurysm was detected during a routine CT scan and was treated interventionally with a stent-graft. One month later the asymptomatic patient underwent a vascular ultrasound examination including color Doppler, power Doppler, and B-flow as a routine control. An endoleak with collapse of the stent-graft was diagnosed. There was no evidence of stent infection. At a reintervention, the pseudoaneurysm was successfully treated using two uncovered Palmaz stents at the proximal and distal edge of the stent graft. Peri- and post-interventional ultrasound and CT angiography confirmed the exclusion of the aneurysm without an endoleak.

  10. Extraction of a migrated coil from the Enterprise stent strut using a Solitaire AB stent.

    PubMed

    Ge, Huijian; Jin, Hengwei; Li, Youxiang; Lv, Xianli

    2016-12-01

    A 56-year-old woman was admitted to stent-assisted coiling for a 2-mm A1 aneurysm of the left anterior cerebral artery and a left 3-mm internal carotid artery aneurysm. While coiling the A1 aneurysm, the first 2 mm × 20 mm coil migrated through the 4.5 mm × 37 mm Enterprise stent struts, lodging at the distal anterior cerebral artery. A 4 mm × 15 mm Solitaire AB stent was used successfully in this case to remove the displaced coil. The A1 aneurysm was re-treated with a 2 mm × 40 mm coil after placement of the Enterprise stent, and the ophthalmic ICA aneurysm was also coiled through the stent struts. The patient was neurologically intact after treatment. © The Author(s) 2016.

  11. Stent

    MedlinePlus

    ... of coronary artery disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: ... Atherosclerotic peripheral arterial disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: ...

  12. Fully biodegradable coronary stents : progress to date.

    PubMed

    Ramcharitar, Steve; Serruys, Patrick W

    2008-01-01

    The limitations of currently available metallic drug-eluting stents have renewed interest in biodegradable stents (BDS). Apart from removing the (offending) foreign material that may potentiate a thrombotic event, BDS have the advantage of avoiding 'full metal jackets,' and thus can preclude subsequent coronary surgery. In addition, they do not interfere with the diagnostic evaluation of non-invasive imaging such as cardiac magnetic resonance and CT. There are now several BDS in development or in clinical trials that incorporate a variety of biodegradable polymer technologies. Two broad categories of materials are generally used: those made from organic biopolymers and those made from corrodible metals. However, to date, none of the materials/stents tested have been able to establish a perfect balance between biocompatibility, the kinetics of degradation needed to maintain mechanical strength to limit recoil, and inflammation. However, studies, such as the ABSORB trial with the everolimus eluting poly-L-lactide stent, which demonstrated comparable restenotic rates with bare metallic stents and a low incidence of major adverse cardiac events (MACE) at 12 months of 3.3%, with only one patient having a non-Q-wave myocardial infarction and no target lesion revascularization, suggest that there has been significant progress with respect to the earlier prototypes. The acute recoil observed could potentially be addressed with the polytyrosine REVA stent currently being evaluated in the RESORB trial, which incorporates a novel locking mechanism within its design. Alternative BDS designs include the combination of an antiproliferative drug with endothelial progenitor cell capturing antibodies to facilitate epithelialization and/or dual eluting having, in addition to the antiproliferative drug, polymeric salicyclic acid to limit inflammation. Compared with biodegradable polymers, there are fewer metals used in the manufacture of BDS. The only metal BDS in trials is the

  13. Stent Coating Integrity of Durable and Biodegradable Coated Drug Eluting Stents.

    PubMed

    Yazdani, Saami K; Sheehy, Alexander; Pacetti, Stephen; Rittlemeyer, Brandon; Kolodgie, Frank D; Virmani, Renu

    2016-10-01

    Coatings consisting of a polymer and drug are widely used in drug-eluting stents (DES) and are essential in providing programmable drug release kinetics. Among other factors, stent coating technologies can influence blood compatibility, affect acute and sub-acute healing, and potentially trigger a chronic inflammatory response. The aim of this study was to investigate the short-term (7 and 28 days) and long-term (90 and 180 days) coating integrity of the Xience Prime Everolimus-Eluting Stent (EES), Resolute Zotarolimus-Eluting Stent (ZES), Taxus Paclitaxel-Eluting Stent (PES), and Nobori Biolimus A9-Eluting Stent (BES) in a rabbit ilio-femoral stent model. Stented arteries (n = 48) were harvested and the tissue surrounding the implanted stents digested away with an enzymatic solution. Results demonstrated that the majority of struts of EES were without any coating defects with a few struts showing minor defects. Similarly, for the ZES, most of the struts were without coating defects at all time points except at 180 days. The majority of PES demonstrated mostly webbing and uneven coating. In the BES group, the majority of strut coating showed polymer cracking. Overall, the EES and ZES had fewer coating defects than the PES and BES. Coating defects, however increase over time for the ZES, whereas the percent of coating irregularities remained constant for the EES. These results provide, for the first time, a comparison of the long-term durability of these drug-eluting stent coatings in vivo. © 2016, Wiley Periodicals, Inc.

  14. Tricuspid valved stent implantation: novel stent with a self-expandable super-absorbent polymer.

    PubMed

    Iino, Kenji; Lozonschi, Lucian; Metzner, Anja; Marczynski-Bühlow, Martin; Renner, Jochen; Cremer, Jochen; Lutter, Georg

    2011-08-01

    Trans-catheter aortic and pulmonary valve replacement procedures can result in favorable outcomes in selected patients. The aim of this study was to investigate the functioning of a novel self-expanding valved stent with super-absorbent polymer (SAP) for minimally invasive replacement of the tricuspid valve. A newly designed nitinol stent with SAP was specially designed for the tricuspid annulus. This device was composed of right atrial anchoring elements, a left ventricular tubular stent, and a trileaflet bovine pericardial valve. The stent was coated with a waterproof material, and a pouch containing SAP for minimizing paravalvular leakage was placed beneath the atrial element. Seven pigs underwent minimally invasive off-pump tricuspid valved stent implantation. This was performed through a lower ministernotomy using a transventricular approach under transesophageal echocardiographic guidance. After 1 and 6h, a complete echocardiographic evaluation and hemodynamics (Swan-Ganz catheter) were performed. Six of seven pigs exhibited normal hemodynamics immediately after tricuspid valved stent implantation and maintained stability for the entire period of monitoring. In one pig, a part of the atrial stent elements was deployed into the right ventricle, leading to significant paravalvular leakage, and died very soon. All subsequent animals survived with good results in the observation period. Accurate positioning of the valved stent was documented in six of seven pigs. SAP expanded and filled the gap between the stent and the native annulus in all animals. Mild paravalvular leakage was found in two of the six animals. Nevertheless, the observed leakage decreased to trace levels 6h after implantation. In the additional four pigs, only trace tricuspid regurgitation was revealed. No right ventricular outflow tract obstruction was detected. Trans-apical off-pump tricuspid valved stent implantation is feasible in an acute experimental setting, and SAP may help to reduce

  15. Percutaneous Endoluminal Stent and Stent-Graft Placement for the Treatment of Femoropopliteal Aneurysms: Early Experience

    SciTech Connect

    Mueller-Huelsbeck, Stefan; Link, Johann; Schwarzenberg, Helmut; Walluscheck, Knut P.; Heller, Martin

    1999-03-15

    Purpose: To determine the efficacy of percutaneous endoluminal stents and stent-grafts for the treatment of isolated femoropopliteal aneurysms. Methods: Seven men (age 51-69 years) with femoropopliteal occlusions (n= 6) related to aneurysms and a patent femoropopliteal aneurysm (n= 1) were treated percutaneously. In two patients uncovered Wallstents and in five patients polyester-covered nitinol stents were implanted. Assessment was performed with Doppler ultrasound and duplex ultrasonography 24 hr, 1, 3, 6, 12, and 24 months after the intervention. Additionally, intraarterial angiography was performed at 6 months. Results: Stent placement succeeded in all cases. No immediate adjunctive surgical treatment was necessary. Ankle-brachial index (ABI) improved from 0.29 {+-} 0.29 (SD) before to 0.78 {+-} 0.23 (SD) 24 hr after the intervention. One patient was lost to follow-up. Stent-graft occlusion occurred in four patients: after 2 days (n1), 1 month (n= 2), and 3 months (n= 1). One of the patients, whose stent occluded at 1 month, underwent successful recanalization with local fibrinolysis therapy. Three of the seven, all with three-vessel run-off, demonstrated patency of the stent, which was assessed by duplex ultrasonography at 29, 31, and 34 months. Breaking of the stent struts or significant stent migration was not observed. Conclusions: These results in a small number of patients warrant further investigation to evaluate the role of percutaneous stents in femoropopliteal aneurysms. Until further data of clinical studies are available, this method cannot be recommended, and it cannot replace surgical treatment.

  16. Extent and distribution of in-stent intimal hyperplasia and edge effect in a non-radiation stent population.

    PubMed

    Weissman, N J; Wilensky, R L; Tanguay, J F; Bartorelli, A L; Moses, J; Williams, D O; Bailey, S; Martin, J L; Canos, M R; Rudra, H; Popma, J J; Leon, M B; Kaplan, A V; Mintz, G S

    2001-08-01

    Intimal hyperplasia within the body of the stent is the primary mechanism for in-stent restenosis; however, stent edge restenosis has been described after brachytherapy. Our current understanding about the magnitude of in vivo intimal hyperplasia and edge restenosis is limited to data obtained primarily from select, symptomatic patients requiring repeat angiography. The purpose of this study was to determine the extent and distribution of intimal hyperplasia both within the stent and along the stent edge in relatively nonselect, asymptomatic patients scheduled for 6-month intravascular ultrasound (IVUS) as part of a multicenter trial: Heparin Infusion Prior to Stenting. Planar IVUS measurements 1 mm apart were obtained throughout the stent and over a length of 10 mm proximal and distal to the stent at index and follow-up. Of the 179 patients enrolled, 140 returned for repeat angiography and IVUS at 6.4 +/- 1.9 months and had IVUS images adequate for analysis. Patients had 1.2 +/- 0.6 Palmaz-Schatz stents per vessel. There was a wide individual variation of intimal hyperplasia distribution within the stent and no mean predilection for any location. At 6 months, intimal hyperplasia occupied 29.3 +/- 16.2% of the stent volume on average. Lumen loss within 2 mm of the stent edge was due primarily to intimal proliferation. Beyond 2 mm, negative remodeling contributed more to lumen loss. Gender, age, vessel location, index plaque burden, hypercholesterolemia, diabetes, and tobacco did not predict luminal narrowing at the stent edges, but diabetes, unstable angina at presentation, and lesion length were predictive of in-stent intimal hyperplasia. In a non-radiation stent population, 29% of the stent volume is filled with intimal hyperplasia at 6 months. Lumen loss at the stent edge is due primarily to intimal proliferation.

  17. [Cost-effectiveness trial of self-expandable metal stents and plastic biliary stents in malignant biliary obstruction].

    PubMed

    Daróczi, Tímea; Bor, Renáta; Fábián, Anna; Szabó, Ella; Farkas, Klaudia; Bálint, Anita; Czakó, László; Rutka, Mariann; Szűcs, Mónika; Milassin, Ágnes; Molnár, Tamás; Szepes, Zoltán

    2016-02-14

    Self-expandable metal and plastic stents can be applied in the palliative endoscopic treatment of patients with unresectable malignant biliary obstruction. The use of metal stentsis recommended if the patient's life expectancy is more than four months. To compare the therapeutic efficacy and cost-effectiveness of metal and plastic stents in the treatment of malignant biliary obstruction. The authors retrospectively enrolled patients who received metal (37 patients) or plastic stent (37 patients). The complication rate, stent patency and cumulative cost of treatment were assessed in the two groups. The complication rate of metal stents was lower (37.84% vs. 56.76%), but the stent patency was higher compared with plastic stents (19.11 vs. 8.29 weeks; p = 0.0041). In the plastic stent group the frequency of hospitalization of patients in context with stent complications (1.18 vs. 2.32; p = 0.05) and the necessity of reintervention for stent dysfunction (17 vs. 27; p = 0.033) were substantially higher. In this group multiple stent implantation raised the stent patency from 7.68 to 10.75 weeks. There was no difference in the total cost of treatment of malignant biliary obstruction between the two groups (p = 0.848). Considering the cost of treatment and the burden of patients the authors recommend self-expandable metal sten timplantation if the life expectancy of patients is more than two months. In short survival cases multiple plastic stent implantation is recommended.

  18. Difference in security of stent jail between Palmaz-Schatz, NIR, and Multi-Link stents: the effect of balloon inflation through stent struts.

    PubMed

    Kinoshita, T; Kobayashi, Y; De Gregorio, J; Nameki, M; Kuroda, N; Yamamoto, Y; Miyazaki, A; Masuda, Y

    1999-10-01

    After placing a stent in the main vessel of a bifurcation lesion, it is often necessary to perform further balloon inflation or stent placement through the stent struts in order to treat a lesion of the secondary vessel or side branch. This balloon inflation with dilatation through the cells of the stent in the main vessel results in stent strut disfigurement. This disfigurement causes various degrees of stenosis within the main vessel secondary to stent strut deformity. The degree of strut deformity, and therefore stenosis, may vary significantly depending on stent design and structure. A model of a bifurcation lesion with an angle of 45 degrees was created from acrylic resin. The diameters of the main vessel and the secondary vessel were both 3.5 mm. Deployment of the Palmaz-Schatz stent (PS, n = 5), NIR stent (n = 5), or Multi-Link stent (n = 5) was performed in the main vessel with a 3.5-mm balloon catheter inflated to 6 atm. A second 3.5-mm balloon catheter was then inflated to 6 atm through the stent struts of the main vessel and into the ostium of the secondary vessel. The minimal lumen diameter (MLD) and cross-sectional area (CSA) at the ostium of the side branch and the stenosis within the main vessel were then measured, taking into account the stent deformity that occurred. Kissing balloon dilatation with two 3.5-mm balloon catheters was then performed and the stenosis secondary to stent deformity in the main vessel was remeasured. The MLD of the Multi-Link stent at the side-branch ostium was greater compared with those of the Palmaz-Schatz stent or the NIR stent (2.4 +/- 0.1, 1.6 +/- 0.1, 1.7 +/- 0.1 mm, P < 0.01) and CSA (4.9 +/- 0.5, 2.7 +/- 0.3, 2.5 +/- 0.3 mm(2), P < 0.01). Balloon inflation through the stent struts caused stent deformity that resulted in some degree of stenosis within the stent of the main vessel in all three stent types. Kissing balloon inflation reduced, but never eliminated, this stenosis. The percent stenosis in the main vessel

  19. What Are the Risks of Having a Stent?

    MedlinePlus

    ... Having a Stent? Risks Related to Percutaneous Coronary Intervention Percutaneous coronary intervention (PCI), the procedure used to place stents, is ... as part of a procedure called percutaneous coronary intervention or PCI, sometimes called angioplasty. Shows how a ...

  20. Preprocedural planning for endovascular stent-graft placement.

    PubMed

    Kicska, Gregory; Litt, Harold

    2009-03-01

    Endovascular stent grafts have become a viable treatment for aortic thoracic and abdominal aneurysms in both elective and emergent situations. Computed tomographic (CT) angiography is the primary tool for determining eligibility for this procedure. This article discuses the preprocedural evaluation of an endovascular stent candidate. Evaluation begins with identification of the aneurysm pathology and its relationship to treatment efficacy. The radiologist must evaluate the aneurysm geometry for compatibility with stent hardware. Aneurysm features that suggest a contraindication must be recognized. Procedures that involve a combination of endovascular stenting and surgical revascularization are discussed so that the reader understands the limits of stent eligibility. Vascular access for stent placement must also be evaluated for the ability to accommodate stent delivery. The radiologist also must be familiar with CT imaging protocols and alternative methods of imaging that can evaluate stent feasibility. The utility of three-dimensional processing is discussed.

  1. Stent thrombosis in 2008: definition, predictors, prognosis and treatment.

    PubMed

    Lemesle, Gilles; Delhaye, Cédric; Bonello, Laurent; de Labriolle, Axel; Waksman, Ron; Pichard, Augusto

    2008-01-01

    Stent thrombosis remains a major pitfall of stent implantation in contemporary percutaneous coronary intervention, leading to high rates of death and nonfatal myocardial infarction (MI). Recently, the emergence of drug-eluting stents (DES) has raised concerns regarding the occurrence of late and very late stent thrombosis. Last year, a standardized definition of stent thrombosis was established to provide consistency in the reporting of this complication and to enable accurate and reliable data to be described for both types of stents: bare metal and drug eluting. Subsequent to the publication of this new definition, many updated data have been reported in the literature. On the other hand, antiplatelet therapy response variability is a recent concept and its real place in the pathogenesis of stent thrombosis is yet to be determined. In this article, we review the definition of and predictors for stent thrombosis focusing on DES use and variability in response to antiplatelet therapy, prognosis and treatment.

  2. Fracture of Memotherm Metallic Stents in the Biliary Tract

    SciTech Connect

    Peck, Robert; Wattam, John

    2000-01-15

    In a series of 66 patients who had palliation of malignant obstructive jaundice by percutaneous placement of Memotherm expanding metal stents, we report four cases of stent fracture. This has not been reported previously.

  3. Trimming a Metallic Biliary Stent Using an Argon Plasma Coagulator

    SciTech Connect

    Rerknimitr, Rungsun Naprasert, Pisit; Kongkam, Pradermchai; Kullavanijaya, Pinit

    2007-06-15

    Background. Distal migration is one of the common complications after insertion of a covered metallic stent. Stent repositioning or removal is not always possible in every patient. Therefore, trimming using an argon plasma coagulator (APC) may be a good alternative method to solve this problem. Methods. Metallic stent trimming by APC was performed in 2 patients with biliary Wallstent migration and in another patient with esophageal Ultraflex stent migration. The power setting was 60-100 watts with an argon flow of 0.8 l/min. Observations. The procedure was successfully performed and all distal parts of the stents were removed. No significant collateral damage to the nearby mucosa was observed. Conclusions. In a patient with a distally migrated metallic stent, trimming of the stent is possible by means of an APC. This new method may be applicable to other sites of metallic stent migration.

  4. Two Fatal Complications after Parallel Tracheal-Esophageal Stenting

    SciTech Connect

    Binkert, Christoph A.; Petersen, Bryan D.

    2002-03-15

    Two patients with malignant obstructions of both the trachea and esophagus underwent parallel stent placement with Gianturco-Roesch Z (GRZ) stents for palliation of symptoms. Fatal hemorrhage occurred in both patients 2 and 3 weeks after stent placement respectively. An autopsy performed on one of these patients demonstrated esophageal tissue necrosis and erosion with perforation of both the tracheal and esophageal walls at sites where the stent struts were in direct opposition, leading to bleeding from the esophageal venous plexus. GRZ stents have been successful in the treatment of both solitary tracheal and esophageal stenoses. However, parallel tracheal-esophageal stenting with GRZ stents places patients at high risk for complications due to the high radial force exerted by this particular stent and the minimal amount of intervening tissue between the two structures.

  5. A review on fracture prevention of stent in femoropopliteal artery

    NASA Astrophysics Data System (ADS)

    Atan, Bainun Akmal Mohd; Ismail, Al Emran; Taib, Ishkrizat; Lazim, Zulfaqih

    2017-01-01

    Heavily calcific lesions, total occlusions, tortuous blood vessels, variable lengths of arteries, various dynamic loads and deformations in the femoropopliteal (FP) arterial segment make stenosis treatments are complicated. The dynamic forces in FP artery including bending, torsion and radial compression may lead to stent fracture (SF) and eventually to in-stent restenosis (ISR). Stent design specifically geometrical configurations are a major factor need to be improved to optimize stent expansion and flexibility both bending and torsion during stent deployment into the diseased FP artery. Previous studies discovered the influence of various stent geometrical designs resulted different structural behaviour. Optimizing stent design can improve stent performances: flexibility and radial strength to prevent SF in FP arterial segment

  6. Metallic Stents for Tracheobronchial Pathology Treatment

    SciTech Connect

    Serrano, Carolina; Laborda, Alicia; Lozano, Juan M.; Caballero, Hugo; Sebastian, Antonio; Lopera, Jorge; Gregorio, Miguel Angel de

    2013-12-15

    Purpose: To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. Patients and Methods: One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. Results: The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 {+-} 1.2 months in patients with malignant lesions and 76.2 {+-} 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. Conclusion: Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results.

  7. Broken Esophageal Stent Successfully Treated by Interventional Radiology Technique

    SciTech Connect

    Zelenak, Kamil; Mistuna, Dusan; Lucan, Jaroslav; Polacek, Hubert

    2010-06-15

    Esophageal stent fractures occur quite rarely. A 61-year-old male patient was previously treated for rupture of benign stenosis, occurring after dilatation, by implanting an esophageal stent. However, a year after implantation, the patient suffered from dysphagia caused by the broken esophageal stent. He was treated with the interventional radiology technique, whereby a second implantation of the esophageal stent was carried out quite successfully.

  8. Treatment of Vertebro-Basilar Dissecting Aneurysms Using Intravascular Stents

    PubMed Central

    Yamasaki, S.; Hashimoto, K.; Kawano, Y.; Yoshimura, M.; Yamamoto, T.; Hara, M.

    2006-01-01

    Summary Endovascular surgery is an established primary therapeutic modality for dissecting aneurysms at vertebro-basilar arteries. Intravascular stents can be used to treat the dissecting aneurysms for which simple obliteration procedures cannot be used. In such cases, stent implantation alone or a combination of stents and coils need to be selected properly by taking into consideration the site and shape of dissections. In this report, three patterns of stent application are described and their method of selection is discussed. PMID:20569619

  9. Gastroesophageal stenting for the management of post sleeve gastrectomy leak

    PubMed Central

    Guzaiz, Noha; Arabi, Mohammad; Khankan, Azzam; Salman, Refaat; Al-Toki, Mohammed; Qazi, Shahbaz; Alzakari, Abdulmohsin; Al-Moaiqel, Mohammad

    2016-01-01

    Objectives To retrospectively evaluate the effectiveness of gastroesophageal stenting for post sleeve gastrectomy staple line leaks using removable self-expandable stents. Methods Between April 2012 and June 2015, 12 consecutive patients (6 males) with mean age of 34 years: (21-38 years) presented with staple line leak 1-8 weeks after the operation (mean 2.8 weeks). Patients underwent gastroesophageal stenting by interventional radiology. A total of 23 stents were deployed with mean length of 17.8 cm (7-24 cm) and mean diameter 25.6 mm (18-36 mm). Stent re-insertion was needed in 7 patients (9 procedure), while 6 patients required percutaneous collection drainage and 3 patients required endoscopic glue injection with clipping. Two stent removal procedures were carried out under endoscopic visualization after failed stent capture under fluoroscopy, while the remaining stents were successfully removed by interventional radiology. Results Stent placement was technically successful in all patients. Stent migration occurred in 6 patients (50%). There is a tendency for stent migration with shorter stent length (R= -0.557, p=0.008). The mean duration of stenting was 60.5 days (14-137 days). All patients underwent stent removal and resumed oral intake with no recurrence of leak at a mean follow up time of 190 days (14-410 days). Complications included gastrointestinal bleeding (n=1), proximal esophageal stricture (n=1) and stent occlusion (n=1). Conclusion Gastroesophageal stenting as a primary measure after diagnosis of early post sleeve gastrectomy leak appears to offer a safe and effective alternative option in obviating repeat surgical interventions. Minimally invasive interventions may still be required for the management of persistent leak. PMID:27874149

  10. A Migrated Aortic Stent Graft Causing Erosive Spondylopathy

    SciTech Connect

    Gestrich, Christopher Probst, Chris; Wilhelm, Kai; Schiller, Wolfgang

    2013-12-15

    We report about a patient presenting with back pain 4 months after an uneventful endovascular implantation of an aortic stent graft. Computed tomography scan revealed a migration of the stent with consecutive endoleakage, kink formation, and movement of the stent toward the spine, which caused destruction of the aortic wall as well as vertebral necrosis. Explantation of the stent and replacement of the native aorta relieved the patient of his symptoms.

  11. Stenting for a symptomatic posterior cerebral artery stenosis.

    PubMed

    Xu, Gelin; Zheng, Ling; Zhou, Zhiming; Liu, Xinfeng

    2009-05-01

    Evolvement of endovascular devices and increase of operator expertise have made angioplasty and stenting in intracranial vessels technically possible. Stenting has been reported in treating stenosis in middle and anterior cerebral arteries with favorable outcomes. However, the feasibility of stenting for stenosis in posterior cerebral artery (PCA) has not been established. We report a patient with progressive focal cerebral ischemic symptoms, which were arrested after reconstruction of the associated PCA stenosis with stenting.

  12. Nasolacrimal Stenting: Toward Improving Outcomes with a Simple Modification of the Song Stent

    SciTech Connect

    Lanciego, Carlos Miguel, Silvia De; Padilla, Manuel; Perea, Miguel; Rodriguez-Merlo, Rufo; Garcia-Garcia, Lorenzo

    2006-08-15

    The purpose of this study was to evaluate, in a prospective, single-center study, the effectiveness of Song's polyurethane stents, modified 'in-house,' in the percutaneous management of epiphora. Patients (n = 170; age range 18-83, mean = 64; 50 male, 120 female) with severe epiphora had the modified stents inserted (183 eyes/195 stents) to treat unilateral/bilateral and complete/partial obstruction of the nasolacrimal system. The etiology of the obstruction was idiopathic in 119 cases (61%) and chronic dacryocystitis in 76 (39%). The set designed by Song was used in all patients but modified by us such that the extreme end is cone-shaped. The original technique was slightly modified by us and the procedure was conducted on an outpatient basis. The initial technical success rate of stent placement was 97%. Resolution of epiphora was complete in 180 eyes and partial in 3. On follow-up (mean = 18 months; range: 2 days to 24 months), 165 of 195 stents (85%) remained patent. Primary patency rates at follow-up were 86%, 84%, 84%, and 79% in the first 6 months, second and third 6 months, and the present (24 months), respectively. Stents became obstructed in 30 patients, but all but 2 were easily withdrawn and 20 of these patients remained asymptomatic for a mean of 14 months (secondary patency of 67%). Following stent removal, the withdrawn stent was replaced with a new stent in the same intervention on 14 occasions. In another six cases, patency was re-established without the need of a second stent. The procedure is simple and safe, both in stent insertion as well as in mechanical de-blocking and withdrawal when occluded. Success was >80 % in the short term (1-year follow-up). Stenting failure does not preclude other treatment because with the modification that we had introduced, the extreme end of the stent becomes more accessible to mechanical de-blocking, withdrawal, and relocation. The levels of primary and secondary patencies are promising and warrant more

  13. A simple technique to remove migrated esophageal stents.

    PubMed

    Noyer, C M; Forohar, F

    1998-09-01

    A 51-yr-old man with a tracheoesophageal fistula from an esophageal carcinoma had two expandable covered stents placed, which migrated distally. After several unsuccessful attempts to remove the stents, we fashioned a homemade snare to entrap and remove the stents under endoscopic and fluoroscopic guidance.

  14. Towards Individualized Tracheobronchial Stents: Technical, Practical and Legal Considerations.

    PubMed

    Freitag, Lutz; Gördes, Martin; Zarogoulidis, Paul; Darwiche, Kaid; Franzen, Daniel; Funke, Faustina; Hohenforst-Schmidt, Wolfgang; Dutau, Hervé

    2017-01-01

    Stent placement has been established as a standard procedure for treating airway obstructions. Other indications are localized malacias and fistulas. Though many different stents with various diameters and lengths are available, the shapes are hardly ever ideal because of the distorted anatomy in patients with diseased airways. There are technical and legal limitations for customizing purchased airway stents. Individually tailored stents would be preferable. New techniques of additive manufacturing such as 3D printing make it possible to produce optimized stents for a particular patient. Using CT data and bronchoscopic images, stents can be constructed that match a particular anatomical situation and apply the optimized expansion force. We give an overview of the currently available manufacturing techniques for polymeric stents and report about our own experience. Direct on-site printing of polyurethane stents in a hospital and printing individual extrusion molds for silicone stents in a certified cleanroom are both feasible. Furthermore, there are promising attempts of combining mechanically customized stents with surface modifications, drug-eluting features, biodegradability, and time-dependent adaptation (4D printing). Truly optimized airway stents with the potential of solving the well-known stent problems such as granulation tissue formation, remodeling, mucostasis, and infections are in reach. The technical hurdles are probably easier to overcome than the legal constraints. The legal situations are discussed from a physician's and a manufacturer's perspective. © 2017 S. Karger AG, Basel.

  15. Modification of tubeless percutaneous nephrolithotomy with a ureteropelvic junction stent.

    PubMed

    Zhou, Tian C; Stern, Joshua M

    2017-10-01

    To introduce the ureteropelvic junction stent as a safe and effective modification to tubeless percutaneous nephrolithotomy for select patients to maintain antegrade access to the collecting system. From April 2014 to December 2015, 31 patients underwent modified tubeless percutaneous nephrolithotomy with ureteropelvic junction (UPJ) stent left in situ and an extraction string coming out the nephrostomy tract. Primary study endpoints included complications, emergency department visits, or re-admissions. Secondary endpoints were perioperative parameters including mean operative time, blood loss, length of stay, and time to stent removal. There were three Clavien grade III complications: one patient required exchange of her UPJ stent with a double-J stent due to distal ureteral obstruction and two patients required ureteroscopic retrieval of retained stents. Minor issues included one patient with stent discomfort and another who experienced a vasovagal response during stent removal. Patients stayed an average of 2.2 +/- 1.5 days, including six discharged same day. Of 31 patients, 30 were successfully drained by ureteropelvic junction stent. UPJ stent is a safe and effective modification to percutaneous nephrolithotomy to maintain antegrade access and minimize stent discomfort. Further studies should be performed to determine optimal candidate selection and quantify stent-related symptoms.

  16. Endotracheal nitinol stents: lessons from the learning curve.

    PubMed

    Siegel, Bianca; Bent, John P; Ward, Robert F

    2013-04-01

    To reflect on lessons learned placing endotracheal nitinol stents in children. Case series with chart review. Tertiary care children's hospital. All children who underwent nitinol cervical tracheal stenting were included. Records were carefully reviewed for intraoperative and postoperative complications, management choices, outcomes, and factors that influenced results. Between 1999 and 2011, 7 children underwent 13 stent placements. Median follow-up was 5 years (range, 1-12 years). Six patients underwent stenting as a salvage procedure following open attempts at airway reconstruction. Four patients remain decannulated with their stent in place (median follow-up 7 years). The fifth patient had his stent removed endoscopically after 50 days because it became apparent that his obstruction was primarily laryngeal. The sixth child had his stent removed via a tracheal fissure after 14 months because of recalcitrant subglottic inflammation at the superior stent border. The seventh patient was decannulated for over 2 years but ultimately required tracheotomy replacement because of stenosis with the stent lumen. Complications included stent migration (23%), restenosis (29%), edema (29%), and granulation (57%). Endotracheal nitinol stents provide a realistic opportunity for decannulation in children for whom other options have failed but should be reserved only as a salvage procedure in severely complicated airways. Our experience has taught valuable lessons about stent indications, sizing, characteristics, and deployment, as well as means to avoid and manage their complications.

  17. The forgotten biliary stent: an unusual cause of diarrhea.

    PubMed

    Sran, Harkiran; Sebastian, Joseph; Doughan, Samer

    2016-09-01

    This case highlights the possible complications of biliary stents, which may include migration and impaction in the gastrointestinal tract. It also emphasizes the need for a robust follow-up system after stent placement, to minimize the risks and possible sequelae of a forgotten stent.

  18. Long-term follow-up of stent implantation versus stent-like angioplasty in unstable angina.

    PubMed

    Marzocchi, A; Ortolani, P; Piovaccari, G; Marrozzini, C; Palmerini, T; Marinucci, L; Saia, F; Bacchi-Reggiani, M L; Branzi, A; Magnani, B

    1999-03-01

    Stent-like plain old balloon angioplasty (POBA, < or = 30% residual diameter stenosis) in patients with stable angina resulted in a clinical and angiographic long-term outcome equivalent to stenting. In unstable angina POBA showed lower acute and long-term efficacy than in the stable setting. Data comparing stent-like POBA and coronary stenting in unstable angina are lacking in the literature. The aim of this retrospective single-center study was to compare the long-term effectiveness of stent-like POBA and coronary stenting in unstable angina. From January 1996 to December 1996 we retrospectively examined 187 consecutive patients with unstable angina who underwent coronary angioplasty on a native vessel: 135 had coronary stenting in addition to POBA and 50 achieved a stent-like result with POBA. Two patients, with major contraindication to coronary stenting, who did not reach a stent-like angiographic result, were also treated with only POBA but were excluded from the study. Stent implantation indications were: elective (54 stents, 30%), suboptimal angiographic result (104 stents, 58%), and bail-out situation (21 stents, 12%). Stent implantation showed high angiographic (98.5%) and clinical (95.5%) success. Stent thrombosis occurred only in 2 patients (1.5%). At quantitative coronary angiography the stent group showed a higher post-procedure minimal lumen diameter (2.74 +/- 1.25 vs 2.27 +/- 0.58 mm, p = 0.025), acute gain (1.95 +/- 1.28 vs 1.43 +/- 0.57 mm, p = 0.007) and lower residual stenosis diameter (13.89 +/- 7.43 vs 20.4 +/- 7.28%, p = 0.001) than the stent-like POBA group. At 1-year follow-up the stent group showed a higher event-free survival rate (77.9 vs 64.6%, p = 0.009) mainly due to lower recurrence of angina and repetition of percutaneous procedures. Stent-like POBA procedure and baseline lesion length > or = 10 mm proved to be the only independent predictors of long-term ischemic event occurrence. In conclusion, in unstable angina, stent

  19. Intense Inflammatory Reaction to Heparin Polymer Coated Intravascular Palmaz Stents in Porcine Arteries Compared to Uncoated Palmaz Stents

    SciTech Connect

    Goodwin, Scott C.; Yoon, Hyo-Chun; Chen, Gary; Abdel-Sayed, Peter; Costantino, Mary M.; Bonilla, Sheila M.; Nishimura, Earl

    2003-04-15

    The objective of this study was to evaluate the efficacy of heparin-polymer-coated intravascular stents in the reduction of vessel stenosis. Three types of coatings for Palmaz stents were tested: 1) heparin covalently bound to a polyethylene oxide(Hp-PEO) tether; 2) heparin copolymerized with ethylene vinyl acetate(Hp-Elvax) and 3) Elvax alone. Polymer-coated stents and uncoated controls were deployed in the external iliac arteries following endothelial injury in 18 swine. The animals were maintained on anatherogenic diet and examined by angiography at 6 and 12 weeks. The stented segments were then harvested for histopathologic analysis. Both types of heparin-coated stents resulted in increased luminal narrowing as compared to the contralateral uncoated stents. At 6 weeks, average luminal stenosis was 48% for Hp-PEO stents vs 35% for uncoated stents (p < 0.05). At 12 weeks, average luminal stenosis was 36% for Hp-PEO stents vs 26% for uncoated stents(p = NS). For Hp-Elvax stents, the average stenosis was 58% vs 33% for uncoated controls (p <0.05) at 6 weeks and 47% vs 19% for uncoated controls(p < 0.05) at 12 weeks. There was no significant difference between Hp-Elvax stents and Elvax stents(p = NS). Increased luminal narrowing in coated stents was primarily secondary to a marked inflammatory response.Heparin-polyethylene oxide and heparin-ethylene vinyl acetate-coated stents resulted in increased luminal narrowing as compared with uncoated stents, due to a marked inflammatory response.

  20. Effect of Variations in Stent Placement on Outcome of Endoluminal Stenting for Canine Tracheal Collapse.

    PubMed

    Rosenheck, Stephanie; Davis, Garrett; Sammarco, Carl D; Bastian, Richard

    2017-03-14

    The study's objective was to determine effects of relative size and placement location of endoluminal stents on incidence of complications and survival for canine tracheal collapse. Measurements were obtained on lateral radiographs before and after stenting to determine percent of the trachea occupied by the stent. These values were monitored over time and compared to complication rates and survival. Overall median survival time was 502 days. Six month survival rate was 78%, 1 yr survival was 60%, and 2 yr survival was 26%. Median percent of trachea occupied by the stent at initial placement was 79% (range, 41-93%). Percent of the trachea occupied by the stent at the time of placement did not significantly correlate to complication rate (0.397) or survival time (0.853). Incidence of serious complications was 37%, including granuloma formation, pneumonia, material failure, and stent migration. For patients experiencing serious complications, median survival was shorter, at 208 days, but was not significantly different from survival without serious complications. Within the margins of the data from this study, the proportion of the trachea occupied by the stent at the time of placement does not appear to impact incidence of complications or survival time in dogs with tracheal collapse.

  1. iStent trabecular micro-bypass stent for open-angle glaucoma

    PubMed Central

    Le, Kim; Saheb, Hady

    2014-01-01

    Trabecular micro-bypass stents, commonly known as iStents, are micro-invasive glaucoma surgery (MIGS) devices used to treat open-angle glaucoma. Like other MIGS procedures that enhance trabecular outflow, the iStent lowers intraocular pressure (IOP) by creating a direct channel between the anterior chamber and Schlemm’s canal. iStents are typically implanted at the time of phacoemulsification for patients with open-angle glaucoma and visually significant cataracts. This review summarizes the published data regarding the efficacy, safety, and cost considerations of trabecular micro-bypass stents. Most studies found statistically significant reductions in mean IOP and ocular medication use after combined phacoemulsification with single or double iStent implantation. The devices were found to be very safe, with a safety profile similar to that of cataract surgery. Complications were infrequent, with the most common complications being temporary stent obstruction or malposition, which resolved with observation or secondary procedures. Future studies are needed to evaluate long-term outcomes, patient satisfaction, cost effectiveness, and expanded indications. PMID:25284980

  2. Impact of stent strut design in metallic stents and biodegradable scaffolds.

    PubMed

    Foin, Nicolas; Lee, Renick D; Torii, Ryo; Guitierrez-Chico, Juan Luis; Mattesini, Alessio; Nijjer, Sukhjinder; Sen, Sayan; Petraco, Ricardo; Davies, Justin E; Di Mario, Carlo; Joner, Michael; Virmani, Renu; Wong, Philip

    2014-12-20

    Advances in the understanding of healing mechanisms after stent implantation have led to the recognition of stent strut thickness as an essential factor affecting re-endothelialization and overall long term vessel healing response after Percutaneous Coronary Interventions (PCI). Emergence of Drug-eluting stents (DESs) with anti-proliferative coating has contributed to reducing the incidence of restenosis and Target Lesion Revascularization (TVR), while progress and innovations in stent materials have in the meantime facilitated the design of newer platforms with more conformability and thinner struts, producing lesser injury and improving integration into the vessel wall. Recent advances in biodegradable metal and polymer materials now also allow for the design of fully biodegradable platforms, which are aimed at scaffolding the vessel only temporarily to prevent recoil and constrictive remodeling of the vessel during the initial period required, and are then progressively resorbed thereby avoiding the drawback of leaving an unnecessary implant permanently in the vessel. The aim of this article is to review recent evolution in stent material and stent strut design while understanding their impact on PCI outcomes. The article describes the different metallic alloys and biodegradable material properties and how these have impacted the evolution of stent strut thickness and ultimately outcomes in patients. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Emergency Coronary Stenting with Wiktor Stent Ñ Immediate and Late Results.

    PubMed

    Bertrand; Legrand; Bilodeau; Martinez; Kulbertus

    1997-01-01

    In case of failed angioplasty, coronary stenting has gradually emerged as a non-surgical method to restore vessel patency and optimize coronary blood flow. There is still little clinical and angiographic information on the use of radiopaque single loose interdigitating wire stents in angioplasty complicated by threatened or acute closure. Seventy-one patients received Wiktor stents after threatened vessel closure in 53 cases and acute closure in 18 cases. Stent delivery was successful in 98%. In-hospital death occurred in 1 case (1.4%). Stents occlusion were faced in 10 cases (14%), of which 6 presented early and 4 late after the procedure. Urgent bypass surgery was needed in 9 cases (12%) and 7 patients (10%) developed acute myocardial infarction. Serious bleeding complications occurred in 7 cases (10%) and vascular repair was performed in 4 patients (5%). During a follow-up of 20 +/- 10 months, 2 patients died, no myocardial infarction was observed and recurrence of angina was noted in 17 patients (24%). Angiographic analysis showed an acute gain in minimal lumen diameter of 1.71 +/- 0.22 mm and a late loss of 0.63 +/- 0.17 mm. Angiographic restenosis (diameter stenosis > 50%) presented in 20% of patients. Therefore, Wiktor stenting yields similar results than currently used stents in acute closure and strictly defined threatened vessel closure following angioplasty.

  4. Primary Stenting in Infrarenal Aortic Occlusive Disease

    SciTech Connect

    Nyman, Ulf; Uher, Petr; Lindh, Mats; Lindblad, Bengt; Ivancev, Krasnodar

    2000-03-15

    Purpose: To evaluate the results of primary stenting in aortic occlusive disease.Methods: Thirty patients underwent primary stenting of focal concentric (n = 2) and complex aortic stenoses (n = 19), and aortic or aorto-iliac occlusions (n = 9). Sixteen patients underwent endovascular outflow procedures, three of whom also had distal open surgical reconstructions. Median follow-up was 16 months (range 1-60 months).Results: Guidewire crossing of two aorto-biiliac occlusions failed, resulting in a 93% (28/30) technical success. Major complications included one access hematoma, one myocardial infarction, one death (recurrent thromboembolism) in a patient with widespread malignancy, and one fatal hemorrhage during thrombolysis of distal emboli from a recanalized occluded iliac artery. One patient did not improve his symptoms, resulting in a 1-month clinical success of 83% (25/30). Following restenting the 26 stented survivors changed their clinical limb status to +3 (n = 17) and +2 (n = 9). During follow-up one symptomatic aortic restenosis occurred and was successfully restented.Conclusions: Primary stenting of complex aortic stenoses and short occlusions is an attractive alternative to conventional surgery. Larger studies with longer follow-up and stratification of lesion morphology are warranted to define its role relative to balloon angioplasty. Stenting of aorto-biiliac occlusions is feasible but its role relative to bypass grafting remains to be defined.

  5. Stented artery biomechanics and device design optimization.

    PubMed

    Timmins, Lucas H; Moreno, Michael R; Meyer, Clark A; Criscione, John C; Rachev, Alexander; Moore, James E

    2007-05-01

    The deployment of a vascular stent aims to increase lumen diameter for the restoration of blood flow, but the accompanied alterations in the mechanical environment possibly affect the long-term patency of these devices. The primary aim of this investigation was to develop an algorithm to optimize stent design, allowing for consideration of competing solid mechanical concerns (wall stress, lumen gain, and cyclic deflection). Finite element modeling (FEM) was used to estimate artery wall stress and systolic/diastolic geometries, from which single parameter outputs were derived expressing stress, lumen gain, and cyclic artery wall deflection. An optimization scheme was developed using Lagrangian interpolation elements that sought to minimize the sum of these outputs, with weighting coefficients. Varying the weighting coefficients results in stent designs that prioritize one output over another. The accuracy of the algorithm was confirmed by evaluating the resulting outputs of the optimized geometries using FEM. The capacity of the optimization algorithm to identify optimal geometries and their resulting mechanical measures was retained over a wide range of weighting coefficients. The variety of stent designs identified provides general guidelines that have potential clinical use (i.e., lesion-specific stenting).

  6. Stent hypersensitivity and infection in sinus cavities

    PubMed Central

    Soufras, George D.; Hahalis, George

    2013-01-01

    Persistent mucosal inflammation, granulation tissue formation, hypersensitivity, and multifactorial infection are newly described complications of retained drug-eluting stents from endoscopic sinus surgery for refractory rhinosinusitis. In an important report published in Allergy and Rhinology, a 45-year-old male patient suffering from recalcitrant chronic rhinosinusitis underwent functional endoscopic sinus surgery and was found, for the first time, to have steroid-eluting catheters that were inadvertently left in the ethmoid and frontal sinuses. The retained catheters had caused persistent mucosal inflammation and formation of granulation tissue denoting hypersensitivity reaction. These consequences had induced perpetuation of symptoms of chronic rhinosinusitis. Meticulous removal of the retained stents with the nitinol wings from inflamed tissues of the frontal, ethmoidal, and sphenoethmoidal recesses in which they were completely imbedded was successfully performed without polypoid regrowth. Cultures of specimens taken from both left and right stents showed heavy growth of Stenotrophomonas maltophilia and moderate growth of Klebsiella oxytoca, coagulase negative Staphylococcus, and beta-hemolytic Streptococcus anginosus. Fungal infection was not detected. The current knowledge and experience regarding stent hypersensitivity and infection in relation with the use of stents in sinus cavities is reviewed. PMID:24498522

  7. Esophageal stenting in the setting of malignancy.

    PubMed

    Martinez, Juan Carlos; Puc, Matthew M; Quiros, Roderick M

    2011-01-01

    Esophageal cancer is often diagnosed at an advanced stage, with many patients found to have locoregional or metastatic disease at time of diagnosis. Because of this, cure may be unlikely, leading treatment efforts to focus more on symptom palliation and improving patient quality of life. The majority of patients with advanced disease suffer from some degree of dysphagia. Palliative efforts are therefore directed at relieving dysphagia, allowing patients to manage their oropharyngeal secretions, reduce aspiration risk, and maintain caloric intake orally. A variety of endoscopic treatment modalities have been utilized with these objectives in mind, with options determined by the location and size of the tumor, as well as the patient's expected prognosis. In this article, we review the use of endoscopically-placed stents for palliation in patients with advanced esophageal cancer. We discuss the history of stent use in such cases, as well as more recent developments in stent technology. We give an overview of some of the more commonly used stents in practice, discuss the technique of insertion, and survey the short- and long-term outcomes of stent placement.

  8. Esophageal Stenting in the Setting of Malignancy

    PubMed Central

    Martinez, Juan Carlos; Puc, Matthew M.; Quiros, Roderick M.

    2011-01-01

    Esophageal cancer is often diagnosed at an advanced stage, with many patients found to have locoregional or metastatic disease at time of diagnosis. Because of this, cure may be unlikely, leading treatment efforts to focus more on symptom palliation and improving patient quality of life. The majority of patients with advanced disease suffer from some degree of dysphagia. Palliative efforts are therefore directed at relieving dysphagia, allowing patients to manage their oropharyngeal secretions, reduce aspiration risk, and maintain caloric intake orally. A variety of endoscopic treatment modalities have been utilized with these objectives in mind, with options determined by the location and size of the tumor, as well as the patient's expected prognosis. In this article, we review the use of endoscopically-placed stents for palliation in patients with advanced esophageal cancer. We discuss the history of stent use in such cases, as well as more recent developments in stent technology. We give an overview of some of the more commonly used stents in practice, discuss the technique of insertion, and survey the short- and long-term outcomes of stent placement. PMID:21991527

  9. Oxygen Mass Transport in Stented Coronary Arteries.

    PubMed

    Murphy, Eoin A; Dunne, Adrian S; Martin, David M; Boyle, Fergal J

    2016-02-01

    Oxygen deficiency, known as hypoxia, in arterial walls has been linked to increased intimal hyperplasia, which is the main adverse biological process causing in-stent restenosis. Stent implantation has significant effects on the oxygen transport into the arterial wall. Elucidating these effects is critical to optimizing future stent designs. In this study the most advanced oxygen transport model developed to date was assessed in two test cases and used to compare three coronary stent designs. Additionally, the predicted results from four simplified blood oxygen transport models are compared in the two test cases. The advanced model showed good agreement with experimental measurements within the mass-transfer boundary layer and at the luminal surface; however, more work is needed in predicting the oxygen transport within the arterial wall. Simplifying the oxygen transport model within the blood flow produces significant errors in predicting the oxygen transport in arteries. This study can be used as a guide for all future numerical studies in this area and the advanced model could provide a powerful tool in aiding design of stents and other cardiovascular devices.

  10. Metallic stents in malignant biliary obstruction

    SciTech Connect

    Rieber, Andrea; Brambs, Hans-Juergen

    1997-01-15

    Purpose. Retrospective analysis of our results with metallic stent placement for malignant biliary strictures. We sought to determine parameters that influence stent patency. Methods. A total of 95 Wallstents were implanted in 65 patients (38 men, 27 women; mean age, 65.1 years) with malignant biliary obstruction. Serum bilirubin levels were assessed in 48 patients; the mean value prior to intervention was 15.0 mg/dl. Results. In 12 patients (21%) complications occurred as a result of percutaneous transhepatic drainage. Stent implantation was complicated in 13 patients, but was possible in all patients. A significant decrease in bilirubin level was seen in 83.3% of patients following stent implantation. Approximately 30% of patients developed recurrent jaundice after a mean 97.1 days. In 9 patients (15%) the recurrent jaundice was caused by stent occlusion due to tumor growth. The mean follow-up was 141.8 days, the mean survival 118.7 days. Patients with cholangiocarcinomas and gallbladder carcinomas had the best results. Worse results were seen in patients with pancreatic tumors and with lymph node metastases of colon and gastric cancers. Conclusions. The main predictive factors for occlusion rate and survival are the type of primary tumor, tumor stage, the decrease in bilirubin level, and the general condition of the patient.

  11. Air cholangiography in endoscopic bilateral stent-in-stent placement of metallic stents for malignant hilar biliary obstruction.

    PubMed

    Lee, Jae Min; Lee, Sang Hyub; Jang, Dong Kee; Chung, Kwang Hyun; Park, Jin Myung; Paik, Woo Hyun; Lee, Jun Kyu; Ryu, Ji Kon; Kim, Yong-Tae

    2016-03-01

    Although endoscopic bilateral stent-in-stent (SIS) placement of self-expandable metallic stents (SEMS) is one of the major palliative treatments for unresectable malignant hilar biliary obstruction, post-endoscopic retrograde cholangiopancreatography (ERCP) cholangitis can occur frequently due to inadequate drainage, especially after contrast injection into the biliary tree. The aim of this study is to evaluate the efficacy and safety of air cholangiography-assisted stenting. This study included 47 patients with malignant hilar biliary obstruction who underwent endoscopic bilateral SEMS placement using the SIS technique. They were divided into two groups, air (n = 23) or iodine contrast (n = 24) cholangiography. We retrospectively compared comprehensive clinical and laboratory data of both groups. There were no significant differences found between the two groups with respect to technical success (87% versus 87.5%, air versus contrast group, respectively), functional success (95% versus 95.2%), 30-day mortality (8.3% versus 8.7%) and stent patency. Post-ERCP adverse events occurred in 5 (21.7%) of the patients in the air group and 8 (33.3%) of the patients in the contrast group. Among these, the rate of cholangitis was significantly lower in the air group (4.8% versus 29.2%, p = 0.048). In multivariate analysis, air cholangiography, technical success and a shorter procedure time were significantly associated with a lower incidence of post-ERCP cholangitis. Air cholangiography-assisted stenting can be a safe and effective method for endoscopic bilateral SIS placement of SEMS in patients with malignant hilar biliary obstruction.

  12. The impact of precise robotic lesion length measurement on stent length selection: ramifications for stent savings.

    PubMed

    Campbell, Paul T; Kruse, Kevin R; Kroll, Christopher R; Patterson, Janet Y; Esposito, Michele J

    2015-09-01

    Coronary stent deployment outcomes can be negatively impacted by inaccurate lesion measurement and inappropriate stent length selection (SLS). We compared visual estimate of these parameters to those provided by the CorPath 200® Robotic PCI System. Sixty consecutive patients who underwent coronary stent placement utilizing the CorPath System were evaluated. The treating physician assessed orthogonal images and provided visual estimates of lesion length and SLS. The robotic system was then used for the same measures. SLS was considered to be accurate when visual estimate and robotic measures were in agreement. Visual estimate SLSs were considered to be "short" or "long" if they were below or above the robotic-selected stents, respectively. Only 35% (21/60) of visually estimated lesions resulted in accurate SLS, whereas 33% (20/60) and 32% (19/60) of the visually estimated SLSs were long and short, respectively. In 5 cases (8.3%), 1 less stent was placed based on the robotic lesion measurement being shorter than the visual estimate. Visual estimate assessment of lesion length and SLS is highly variable with 65% of the cases being inaccurately measured when compared to objective measures obtained from the robotic system. The 32% of the cases where lesions were visually estimated to be short represents cases that often require the use of extra stents after the full lesion is not covered by 1 stent [longitudinal geographic miss (LGM)]. Further, these data showed that the use of the robotic system prevented the use of extra stents in 8.3% of the cases. Measurement of lesions with robotic PCI may reduce measurement errors, need for extra stents, and LGM. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. The Casper carotid artery stent: a unique all metal micromesh stent designed to prevent embolic release.

    PubMed

    Diaz, Orlando; Lopez, Gloria; Roehm, John O F; De la Rosa, Ginna; Orozco, Fernando; Almeida, Rafael

    2017-04-24

    Stroke due to the release of embolic debris during the placement of a stent to correct carotid artery stenosis is a constant procedural and peri-procedural threat. The new all metal Casper stent has been created with two layers of nitinol, the inner layer of which has pores diminutive enough to prevent embolic release. To evaluate the safety, effectiveness, and utility of the double layer nitinol Casper carotid artery stent in the treatment of patients with severe carotid artery stenosis. 19 patients with severe internal carotid artery stenosis, 14 symptomatic and 5 asymptomatic, were treated with the Casper stent. After stent placement, angiographic and cone beam CT images were recorded in all patients. The unique low profile delivery system allowed for easy stent placement, re-sheathing, and repositioning of the stent. The large cell external layer produced excellent apposition to the artery wall. The inner layer prevented prolapse of atherosclerotic debris through the device. Plaque coverage was achieved; residual stenosis ranged from 0% to 20%. Long term angiographic follow-up in 5 patients showed wall apposition of the device covering the lesion and no restenosis. There were no procedure related complications. Two patients experienced a delayed ischemic stroke, likely related to inconsistent medical management. The Casper has been an excellent stent for the treatment of internal carotid artery stenosis and its internal micromesh layer has been effective in preventing plaque prolapse. It provides the flexibility of large cell stents and the inner layer provides maximum protection against plaque prolapse. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  14. Intraluminal Radioactive Stent Compared with Covered Stent Alone for the Treatment of Malignant Esophageal Stricture

    SciTech Connect

    Wang Zhongmin; Huang Xunbo; Cao Jun; Huang Gang; Chen Kemin LIu Yu; Liu Fenju

    2012-04-15

    Objective: This study was designed to compare the clinical effectiveness of intraluminal radioactive stent loaded with iodine-125 seeds implantation versus covered stent alone insertion in patients with malignant esophageal stricture. Methods: We studied two groups of patients with malignant esophageal stricture. Group A comprised 28 patients (19 men and 9 women) who underwent intraluminal radioactive stent loaded with iodine-125 seeds implantation and were followed prospectively. Group B comprised 30 patients (18 men and 12 women) who had previously received covered stent alone insertion; these patients were evaluated retrospectively. There was no crossover between the two groups during follow-up. Informed consent was obtained from each patient, and our institutional review board approved the study. The dysphagia score, overall survival rates, complication rates, and reintervention rates were compared in the two groups. Results: There were no significant differences between the two groups in terms of baseline characteristics. Stent placement was technically successful and well tolerated in all patients. The dysphagia score was improved in both groups after stent placement. The median survival was significantly longer in group A than in group B: 11 versus 4.9 months, respectively (P < 0.001). The complications of chest pain, esophageal reflux, and stent migration was more frequent in group B, but this difference did not reach statistical significance. There was no statistical difference in reintervention between two groups. Conclusions: Intraluminal radioactive stent loaded with iodine-125 seeds implantation was a feasible and practical management in treating malignant esophageal stricture and was superior to covered stent alone insertion, as measured by survival.

  15. Biliary stenting in patients with malignant biliary obstruction: comparison of double layer, plastic and metal stents.

    PubMed

    Elwir, Saleh; Sharzehi, Kaveh; Veith, Joshua; Moyer, Mathew T; Dye, Charles; McGarrity, Thomas; Mathew, Abraham

    2013-07-01

    The double layer stent (DLS) has a unique design and has been used for palliation of malignant biliary obstruction, but literature on this stent is limited. Our aim was to compare plastic (PS), DLS and metal stents (MS) in terms of complication rates, time to occlusion, and patency rate in patients with malignant biliary obstruction (MBO). A retrospective review of stents placed for MBO at our institution in the period between January 2009 and April 2011 was conducted. A total of 114 stents were identified, of which 44 were MS (39 %), 37 DLS (32 %), and 33 PS (29 %). A stent was considered occluded when an unplanned stent removal or intervention occurred due to clinical suspicion of biliary obstruction. Stents remained patent for 95 days (range 7-359 days) in the DLS group and 59 days (range 7-228 days) in the PS group (P = 0.014) and 128.7 days (range 4-602 days) in the metal stent group. Twenty-seven percent (n = 9) of PS occluded after a mean of 60 days while 16 % (n = 7) of MS occluded after a mean of 87 days and 5 % (n = 2) of DLS occluded after a mean of 85 days (DLS vs. PS P = 0.012, DLS vs. MS P = 0.13, MS vs. PS P = 0.22). DLS are superior to PS in patients with MBO and appear to be comparable to MS. MS had a longer patency rate but were comparable to DLS in early and late complications. We speculate that the less expensive DLS may be a cost effective alternative in the palliation of MBO.

  16. Initial experience with a new biodegradable airway stent in children: Is this the stent we were waiting for?

    PubMed

    Antón-Pacheco, Juan L; Luna, Carmen; García, Enrique; López, María; Morante, Rocío; Tordable, Cristina; Palacios, Alba; de Miguel, Mónica; Benavent, Isabel; Gómez, Andrés

    2016-06-01

    To report our experience with a new type of biodegradable airway stent in the setting of severe tracheobronchial obstruction in children. We conducted a retrospective and prospective (since June 2014) study of pediatric patients with severe airway obstruction treated with biodegradable stents in our institution between 2012 and 2015. The following data were collected: demographics, indication for stenting, bronchoscopic findings, insertion technique complications, clinical outcome, stent related complications, re-stenting, and time of follow-up. Thirteen custom-made polydioxanone stents were placed in four infants (mean age, 4 months) with severe tracheobronchial obstruction: tracheomalacia (two patients), bronchomalacia (1), and diffuse tracheal stenosis (1). All the stents were bronchoscopically inserted uneventfully. Immediate and maintained clinical improvement was observed in every case. No major stent related complications have occurred and only mild or moderate granulation tissue was observed during surveillance bronchoscopy. Two patients required repeated stenting as expected. All the patients are alive and in a good respiratory condition with a follow-up ranging from 5 to 40 months. Biodegradable airway stents seem to be safe, effective, and cause fewer complications than other types of stents. They can be an alternative to the classic metallic or plastic stents for severe tracheal stenosis or malacia in small children. More experience is needed in order to establish the definite clinical criteria for their use in pediatric patients. Pediatr Pulmonol. 2016;51:607-612. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  17. In vivo evaluation of the third generation biodegradable stent: a novel approach to avoiding the forgotten stent syndrome.

    PubMed

    Chew, Ben H; Paterson, Ryan F; Clinkscales, Kenneth W; Levine, Barry S; Shalaby, Shalaby W; Lange, Dirk

    2013-02-01

    Ureteral stents are prone to irritation, encrustation and infection, and they require additional procedures for removal. Furthermore, indwelling polymer stents are often forgotten with devastating consequences to the patient. We describe the degradation time, and physiological and histological responses elicited by a novel biodegradable ureteral stent in a porcine model. A total of 16 female Yorkshire pigs were used in the study. Ten biodegradable Uriprene™ stents and 6 biostable Polaris™ stents were cystoscopically inserted unilaterally in 2 groups of animals. Excretory urogram, and blood and urine tests were performed on different days until day 28. Biostable stents were removed on day 21. On day 28 all pigs underwent necropsy for microscopic and histological evaluation. Nine of the 10 biodegradable stents (90%) degraded completely by 4 weeks, while 1 pig had 3 fragments smaller than 1.5 cm in the bladder. Excretory urogram showed equivalent drainage and significantly less hydronephrosis in biodegradable stented kidneys. Blood and urine parameters were similar in the 2 groups. A transient increase in serum creatinine on day 7 in 40% of the pigs with a degradable stent resolved by day 10. There were significantly fewer abnormal histological findings in the degradable stent group. We evaluated drainage characteristics in an unobstructed ureter and results may not be representative of what develops in obstructed ureters. The third generation biodegradable stent is a safe, effective alternative to conventional polymer stents, resulting in equivalent drainage and less hydronephrosis. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  18. Migration of Internal Pancreaticojejunostomy Stents into the Bile Ducts in Patients Undergoing Pancreatoduodenectomy.

    PubMed

    Park, So Hyun; Kim, Jin Hee; Noh, Seung Yeon; Byun, Jae Ho; Lee, Seung Soo; Kim, Hyoung Jung; Park, Seong Ho; Lee, Sung Koo; Hwang, Dae Wook; Kim, Song Cheol; Han, Duck Jong; Lee, Moon-Gyu

    2015-11-01

    To investigate the incidence, complications, and risk factors of the migration of internal pancreaticojejunostomy (PJ) stents into the bile ducts in patients undergoing pancreatoduodenectomy. Postoperative computed tomography (CT) and clinical data of 802 patients with CT-detectable internal PJ stents were reviewed to assess the occurrence of stent migration into the bile ducts and stent-induced complications with their clinical significance. Risk factors for stent migration and stent-induced complications were determined. Stent migration into the bile ducts occurred in 135 patients (16.8 %); 40 of these (29.6 %) showed stent-induced complications including bile duct stricture, stone, and liver abscess. Clinically significant complications were identified in only eight patients. Neither the stent length nor diameter was associated with stent migration. A small stent diameter, peripheral location of the stent, absence of stent remigration from the bile ducts to the intestine, and longer stent retention time in the bile ducts were risk factors of stent-induced complications. The incidence of internal PJ stent migration into the bile ducts was 16.8 %. Migrated stents frequently caused complications, although they were mostly subclinical. Stent-induced complications were associated with stent diameter and location, stent remigration to the intestine, and stent retention time in the bile ducts.

  19. Mechanical response of cardiovascular stents under vascular dynamic bending.

    PubMed

    Xu, Jiang; Yang, Jie; Huang, Nan; Uhl, Christopher; Zhou, Yihua; Liu, Yaling

    2016-02-20

    Currently, the effect of vascular dynamic bending (VDB) has not been fully considered when studying cardiovascular stents' long-term mechanical properties, as the previous studies about stent's mechanical properties mostly focus on the effect of vascular pulsation (VP). More and more clinical reports suggested that the effect of VDB have a significant impact on stent. In this paper, an explicit-implicit coupling simulation method was applied to analyze the mechanical responses of cardiovascular stents considering the effect of VDB. The effect of VP on stent mechanical properties was also studied and compared to the effect of VDB. The results showed that the dynamic bending deformation occurred in stents due to the effect of VDB. The effects of VDB and VP resulted in alternating stress states of the stent, while the VDB alternate stresses effective on the stent were almost three times larger than that of the VP. The stress concentration under VDB mainly occurred in bridge struts and the maximal stress was located in the middle loops of the stent. However, the stress distributed uniformly in the stents under the effect of VP. Stent fracture occurred more frequently as a result of VDB with the predicted fracture position located in the bridging struts of the stent. These results are consistent with the reported data in clinical literatures. The stress of the vessel under VDB was higher, than that caused by VP. The results showed that the effect of VDB has a significant impact on the stent's stress distribution, fatigue performance and overall stress on the vessel, thus it is necessary to be considered when analyzing stent's long-term mechanical properties. Meanwhile, the results showed that the explicit-implicit coupling simulation can be applied to analyze stent mechanical properties.

  20. Meta-Analysis of Stenting versus Non-Stenting for the Treatment of Ureteral Stones

    PubMed Central

    Wang, Hai; Man, Libo; Li, Guizhong; Huang, Guanglin; Liu, Ning; Wang, Jianwei

    2017-01-01

    Background and aim Ureteroscopic lithotripsy (URL) and extracorporeal shock wave lithotripsy (ESWL) are two widely used methods for the treatment of ureteral stones. The need for ureteral stenting during these procedures is controversial. In this meta-analysis, we evaluated the benefits and disadvantages of ureteral stents for the treatment of ureteral stones. Methods Databases including PubMed, Embase and Cochrane library were selected for systematic review of randomized controlled trials (RCTs) comparing outcomes with or without stenting during URL and ESWL. Meta-analysis was performed using RevMan 5.3 and STATA 13.0 software. Results We identified 22 RCTs comparing stenting and non-stenting. The stented group was associated with longer operation time (WMD: 4.93; 95% CI: 2.07 to 7.84; p < 0.001), lower stone-free rate (OR: 0.55; 95% CI: 0.34 to 0.89; p = 0.01). In terms of complications, the incidence of hematuria (OR: 3.68; 95% CI: 1.86 to 7.29; p < 0.001), irritative urinary symptoms (OR: 4.40; 95% CI: 2.19 to 9.10; p < 0.001), urinary infection (OR: 2.23; 95% CI: 1.57 to 3.19; p < 0.001), and dysuria (OR: 3.90; 95% CI: 2.51 to 6.07; p < 0.001) were significantly higher in the stented group. No significant differences in visual analogue score (VAS), stricture formation, fever, or hospital stay were found between stenting and non-stenting groups. The risk of unplanned readmissions (OR: 0.63; 95% CI: 0.41 to 0.97; p = 0.04) was higher in the non-stented group. Conclusions Our analysis showed that stenting failed to improve the stone-free rate, and instead, it resulted in additional complications. However, ureteral stents are valuable in preventing unplanned re-hospitalization. Additional randomized controlled trials are still required to corroborate our findings. PMID:28068364

  1. Stent optical inspection system calibration and performance.

    PubMed

    Bermudez, Carlos; Laguarta, Ferran; Cadevall, Cristina; Matilla, Aitor; Ibañez, Sergi; Artigas, Roger

    2017-03-20

    Implantable medical devices, such as stents, have to be inspected 100% so no defective ones are implanted into a human body. In this paper, a novel optical stent inspection system is presented. By the combination of a high numerical aperture microscope, a triple illumination system, a rotational stage, and a CMOS camera, unrolled sections of the outer and inner surfaces of the stent are obtained with high resolution at high speed with a line-scan approach. In this paper, a comparison between the conventional microscope image formation and this new approach is shown. A calibration process and the investigation of the error sources that lead to inaccuracies of the critical dimension measurements are presented.

  2. Stent Thrombosis: Incidence, Predictors and New Technologies

    PubMed Central

    Buchanan, Gill Louise; Basavarajaiah, Sandeep; Chieffo, Alaide

    2012-01-01

    Some concerns have been raised regarding the risk of late and very late stent thrombosis (ST) following drug-eluting stent implantation. Despite remaining an uncommon complication of percutaneous coronary intervention, when ST occurs, it can be catastrophic to the individual, commonly presenting as acute ST elevation myocardial infarction or sudden cardiac death. The incidence and predictors of ST have been reported in the literature and the role of dual antiplatelet therapies in the avoidance of such a complication remains vital. Ongoing studies are assessing the role of these therapies including platelet reactivity testing, genetic testing and optimum duration of therapy. In addition, newer polymer-free and bioabsorbable stents are under investigation in the quest to potentially minimise the risk of ST. PMID:22577541

  3. Gastrointestinal stenting: Current status and imaging features.

    PubMed

    Malgras, B; Lo Dico, R; Pautrat, K; Dohan, A; Boudiaf, M; Pocard, M; Soyer, P

    2015-06-01

    The use of stents in the gastrointestinal tract has been subjected to major changes. Initially, the use of stents was restricted to malignant strictures in patients with metastatic disease. But thanks to reduction of the morbidity and mortality rates, they are now used with curative intention and in patients with benign diseases after careful selection. However, for patients presenting with colon obstruction due to an advanced colon carcinoma, the mortality and morbidity are still high. The purpose of this review is to provide an overview of indications, techniques and further developments of the stents in the gastrointestinal tract and to highlight the predominant role of multidetector row computed tomography (MDCT) in the detection of potential complications. Copyright © 2015 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  4. Biocompatible metallic stent for medical therapy

    NASA Astrophysics Data System (ADS)

    Kathuria, Yash P.

    2003-12-01

    In the stent theory for the medical applications, especially in coronary heart disease, the metallic stent of high quality demands the ability for precision micromaterial processing. It possesses an inherent advantage of adequate radio opacity. This paper describes the current status as well as fabrication of such metallic stent of length 20 mm and dia. 2.1 mm with an annular tube thickness of 0.2 mm, by using the short pulse Nd-YAG laser. Fine structures with slit width of 0.1 mm and pitch better than 0.2 mm are created with sharpness and low roughness in the cut surface. Some features of the reduced heat affected zone and dross removal process of the cut surfaces are also discussed.

  5. Stenting of the Upper Gastrointestinal Tract: Current Status

    SciTech Connect

    Katsanos, Konstantinos; Sabharwal, Tarun Adam, Andreas

    2010-08-15

    Minimally invasive image-guided insertion of self-expanding metal stents in the upper gastrointestinal tract is the current treatment of choice for palliation of malignant esophageal or gastroduodenal outlet obstructions. A concise review is presented of contemporary stenting practice of the upper gastrointestinal tract, and the procedures in terms of appropriate patient evaluation, indications, and contraindications for treatment are analyzed, along with available stent designs, procedural steps, clinical outcomes, inadvertent complications, and future technology. Latest developments include biodegradable polymeric stents for benign disease and radioactive or drug-eluting stents for malignant obstructions.

  6. Nitinol Self-Expanding Stents for the Superficial Femoral Artery.

    PubMed

    Nathan, Ashwin; Kobayashi, Taisei; Giri, Jay

    2017-04-01

    The superficial femoral artery is a complex artery subject to a unique set of biomechanical loading conditions in its course through the leg. Plain balloon angioplasty and balloon-expandable stents had unacceptably high rates of restenosis, necessitating target vessel revascularization. Nitinol alloy is well suited to provide the strength and flexibility needed of stents to withstand the external forces posed by the environment of the superficial femoral artery. Advances in stent technology with the addition of a slow-releasing antiproliferative agent and changes in scaffold design have shown promise in reducing the rates of stent fracture and in-stent restenosis. Published by Elsevier Inc.

  7. Biofilm formation on ureteral stents - Incidence, clinical impact, and prevention.

    PubMed

    Zumstein, Valentin; Betschart, Patrick; Albrich, Werner C; Buhmann, Matthias T; Ren, Qun; Schmid, Hans-Peter; Abt, Dominik

    2017-02-06

    Ureteral stents are a simple, minimally invasive method of maintaining ureteral drainage to assure renal function, treat pain caused by ureteral obstruction and avoid external or visible devices. Ureteral stenting is, however, associated with a clear side-effect profile, including irritation on voiding, pain and haematuria. Complications such as stent dysfunction and clinically significant urinary tract infections are also regularly observed. Although this has not yet been thoroughly researched, it appears that biofilm formation on ureteral stents plays a key role in the associated morbidity. In this review, we summarise the current evidence and identify areas that should be further studied to reduce the morbidity associated with ureteral stenting.

  8. Transradial approach for vertebral artery stenting

    PubMed Central

    Tekieli, Łukasz; Kabłak-Ziembicka, Anna; Paluszek, Piotr; Trystuła, Mariusz; Wójcik-Pędziwiatr, Magdalena; Machnik, Roman; Pieniążek, Piotr

    2015-01-01

    Introductuion Symptomatic severe vertebral artery (VA) stenosis may be treated safely with stent supported angioplasty via femoral access. There is limited clinical data on transradial approach for VA angioplasty in case of peripheral artery disease. Aim To evaluate the safety and efficacy of transradial angioplasty of symptomatic VA stenosis. Material and methods Fifteen patients (age 66 ±7.4 years, 73% men, with VA > 80% stenosis, 11 right-side, all symptomatic from posterior circulation (history of stroke, TIA, or chronic ischaemia symptoms)) with peripheral artery disease (PAD) or unsuccessful attempt via femoral approach were scheduled for VA angioplasty by radial access. Clinical and duplex ultrasound (DUS) follow-up were performed before discharge and 1, 12, and 24 months after VA angioplasty. Results The technical success rate was 100%. In all cases VA angioplasty was performed with the use of single balloon-mounted stent (9 bare metal stents, 6 drug-eluting stents). The mean NASCET VA stenosis was reduced from 85.3% to 5.3% (p < 0.001). No periprocedural death, stroke, myocardial infarction, or transient ischaemic attack occurred. During 24-months follow-up, in 12 of 15 patients chronic ischaemia symptoms release was observed, and no new acute ischaemic neurological symptoms were diagnosed in all patients. One patient died 20 months after intervention from unknown causes. There was one symptomatic borderline VA in-stent stenosis 12 months after angioplasty. Conclusions Transradial VA stenting may be a very effective and safe procedure, and it may constitute an alternative to the femoral approach in patients with symptomatic VA stenosis. PMID:25848368

  9. Biomechanical Challenges to Polymeric Biodegradable Stents.

    PubMed

    Soares, Joao S; Moore, James E

    2016-02-01

    Biodegradable implants have demonstrated clinical success in simple applications (e.g., absorbable sutures) and have shown great potential in many other areas of interventional medicine, such as localized drug delivery, engineered tissue scaffolding, and structural implants. For endovascular stenting and musculoskeletal applications, they can serve as temporary mechanical support that provides a smooth stress-transfer from the degradable implant to the healing tissue. However, for more complex device geometries, in vivo environments, and evolving load-bearing functions, such as required for vascular stents, there are considerable challenges associated with the use of biodegradable materials. A biodegradable stent must restore blood flow and provide support for a predictable appropriate period to facilitate artery healing, and subsequently, fail safely and be absorbed in a controllable manner. Biodegradable polymers are typically weaker than metals currently employed to construct stents, so it is difficult to ensure sufficient strength to keep the artery open and alleviate symptoms acutely while keeping other design parameters within clinically acceptable ranges. These design challenges are serious, given the general lack of understanding of biodegradable polymer behavior and evolution in intimal operating conditions. The modus operandi is mainly empirical and relies heavily on trial-and-error methodologies burdened by difficult, resource-expensive, and time-consuming experiments. We are striving for theoretical advancements systematizing the empirical knowledge into rational frameworks that could be cast into in silico tools for simulation and product development optimization. These challenges are evident when one considers that there are no biodegradable stents on the US market despite more than 30 years of development efforts (and currently only a couple with CE mark). This review summarizes previous efforts at implementing biodegradable stents, discusses the

  10. Elastic recoil of coronary stents: a comparative analysis.

    PubMed

    Barragan, P; Rieu, R; Garitey, V; Roquebert, P O; Sainsous, J; Silvestri, M; Bayet, G

    2000-05-01

    Minimum elastic recoil (ER) has became an essential feature of new coronary stents when deployed in artheromatous lesions of various morphologies. The ER of coronary stent might be an important component of 6-month restenosis rate by minimizing the luminal loss. We evaluated the intrinsic ER of 23 coronary stents with a mechanical test bench. The amount of ER for one size of stent (3.0 mm) was quantified using a 3D optical contactless machine (Smartscope MVP, Rochester, NY). The stents were expanded on their own balloon for the precrimped stents; the uncrimped stents were expended using identical 3.0-mm balloons. Two types of measurements were done without exterior stress and with a 0.2-bar exterior stress, directly on the stent at the end of balloon expansion, immediately after balloon deflation, and then 30 min, 60 min, and 120 min after. ER ranged from 1.54%+/-0.81% (Bestent BES 15) to 16.51%+/-2.89% (Paragon stent) without stress (P<0.01) and from 2.35%+/-1.14% (Bestent BES 15) to 18.34%+/-2.41% (Cook GR2) under 0.2-bar pressure (P<0.0001). Furthermore, there was a significant reduction between the mean result of tubular stents (TS) and coil stents (CS). The results of in vitro mechanical tests may confirm strongly the interest of a minimum ER in the prevention of the 6-month restenosis.

  11. Recent developments in drug-eluting coronary stents.

    PubMed

    Yildiz, Mustafa; Yildiz, Banu Sahin; Gursoy, Mustafa Ozan; Akin, Ibrahim

    2014-01-01

    The interventional treatment of coronary artery disease was introduced in 1970`s by Andreas Grüntzig. The initial treatment strategy with plain old balloon angioplasty (POBA) was associated with high restenosis rates. The introduction of coronary stents, especially drug-eluting stents (DES) in 2002 has improved the results by lowering the rate of in-stent restenosis from 20-40% in the era of bare-metal stent (BMS) to 6-8%. However, in 2006 with the observation of late stent thrombosis the reputations of DES have decreased. However, improvements in stent design especially antiproliferative agents, polymeric agents as well as stent platforms improved newer generation DES. In controlled trials as well as registries the use of second-generation DES as compared to bare-metal stents (BMS) was associated with better clinical and angiographic results. A further development of these stents with use of biodegradable polymers, polymer-free stents, and biodegradable stents on the basis of poly L-lactide (PLLA) or magnesium resulted in third-generation DES and has been evaluated in preclinical and first clinical trials. However, to date, there is a lack of data comparing these third-generation DES with first- and second-generatrion DES in a large scale.

  12. A new polymer-free drug-eluting stent with nanocarriers eluting sirolimus from stent-plus-balloon compared with bare-metal stent and with biolimus A9 eluting stent in porcine coronary arteries

    PubMed Central

    Galon, Micheli Z.; Gutierrez, Paulo S.; Sojitra, Prakash; Vyas, Ashwin; Doshi, Manish; Lemos, Pedro A.

    2015-01-01

    Background Permanent polymers in first generation drug-eluting stent (DES) have been imputed to be a possible cause of persistent inflammation, remodeling, malapposition and late stent thrombosis. We aim to describe the in vivo experimental result of a new polymer-free DES eluting sirolimus from stent-plus-balloon (Focus np stent, Envision Scientific) compared with a bare-metal stent (BMS) (Amazonia CroCo, Minvasys) and with a biolimus A9 eluting stent (Biomatrix, Biosensors). Methods In 10 juvenile pigs, 23 coronary stents were implanted in the coronary arteries (8 Amazonia CroCo, 8 Focus np, and 7 Biomatrix). At 28-day follow-up, optical coherence tomography (OCT) and histology were used to evaluate neointimal hyperplasia and healing response. Results According to OCT analysis, Focus np stents had a greater lumen area and less neointimal hyperplasia response than BMS and Biomatrix had. Histomorphometry results showed less neointimal hyperplasia in Focus np than in BMS. Histology showed a higher fibrin deposition in Biomatrix stent compared to Focus np and BMS. Conclusions The new polymer-free DES with sirolimus eluted from stent-plus-balloon demonstrated safety and reduced neointimal proliferation compared with the BMS and Biomatrix stents at 28-day follow-up in this porcine coronary model. This new polymer-free DES is promising and warrants further clinical studies. PMID:25984451

  13. Fast Virtual Stenting with Active Contour Models in Intracranical Aneurysm

    PubMed Central

    Zhong, Jingru; Long, Yunling; Yan, Huagang; Meng, Qianqian; Zhao, Jing; Zhang, Ying; Yang, Xinjian; Li, Haiyun

    2016-01-01

    Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms (IAs). Image simulation of the releasing stent configuration together with computational fluid dynamics (CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model (ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. In this method, an initial stent mesh was generated along the centerline of the parent artery without the need for registration between the stent contour and the vessel. Additionally, the diameter of the initial stent volumetric mesh was set to the maximum inscribed sphere diameter of the parent artery to improve the stenting accuracy and save computational cost. At last, a novel criterion for terminating virtual stent expanding that was based on the collision detection of the axis aligned bounding boxes was applied, making the stent expansion free of edge effect. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation. PMID:26876026

  14. Controlled Atrial Fibrillation after Pulmonary Vein Stenting

    PubMed Central

    Park, Young-Ah; Seo, Jiwon

    2017-01-01

    When there is no pulmonary vein reconnection after catheter ablation for atrial fibrillation, patients can experience recurrence of atrial fibrillation without clear evidence of non-pulmonary vein foci. We describe a patient with significant pulmonary vein stenosis and recurrent atrial fibrillation after four ablation procedures. After successful pulmonary vein stenting, the symptoms were resolved, and sinus rhythm was maintained for 2 years without treatment with antiarrhythmic medication. We believe pulmonary vein stenting potentially controlled atrial fibrillation by providing pulmonary vein pressure relief or by compressing the epicardial triggers occurring at the pulmonary vein ostium. PMID:28765746

  15. Role of stents and laser therapy in biliary strictures

    NASA Astrophysics Data System (ADS)

    Chennupati, Raja S.; Trowers, Eugene A.

    2001-05-01

    The most frequent primary cancers causing malignant obstructive jaundice were pancreatic cancer (57%), hilar biliary cancer (19% including metastatic disease), nonhilar biliary cancer (14%) and papillary cancer (10%). Endoscopic stenting has widely replaced palliative surgery for malignant biliary obstruction because of its lower risk and cost. Self-expandable metal stents are the preferred mode of palliation for hilar malignancies. Plastic stents have a major role in benign biliary strictures. Major complications and disadvantages associated with metallic stents include high cost, cholangitis. malposition, migration, unextractability, and breakage of the stents, pancreatitis and stent dysfunction. Dysfunction due to tumor ingrowth can be relieved by thermal methods (argon plasma coagulator therapy). We present a concise review of the efficacy of metallic stents for palliation of malignant strictures.

  16. A Case of Late Femoral Pseudoaneurysm Caused by Stent Disconnection

    SciTech Connect

    Rivolta, Nicola; Fontana, Federico; Piffaretti, Gabriele Tozzi, Matteo; Carrafiello, Gianpaolo

    2010-10-15

    We present the case of a late superficial femoral artery stent disconnection causing an asymptomatic pseudoaneurysm successfully treated with a stent-graft. A 67-year-old female was referred to our department for evaluation of claudication of the left lower limb and was diagnosed to have a total occlusion of the superficial femoral artery. Three nitinol stents were used to revascularize this artery. At 48 months, duplex-ultrasonography control revealed the presence of a 45-mm saccular femoral dilatation; X-rays and CT angiography showed fractures of the proximal stents and the presence of a pseudoaneurysm at the site of the distal stents disconnection. The pseudoaneurysm was excluded using two stent-grafts. We conclude that patients and surgeons should be aware of structural complications with all stents. Rigorous follow-up controls should be mandatory. Endovascular repair proved to be feasible and durable to manage a previous endovascular procedure.

  17. Spontaneous Solitaire™ AB Thrombectomy Stent Detachment During Stroke Treatment

    SciTech Connect

    Akpinar, Suha Yilmaz, Guliz

    2015-04-15

    Spontaneous Solitaire™ stent retriever detachment is a rarely defined entity seen during stroke treatment, which can result in a disastrous clinical outcome if it cannot be solved within a critical stroke treatment time window. Two solutions to this problem are presented in the literature. The first is to leave the stent in place and apply angioplasty to the detached stent, while the second involves surgically removing the stent from the location at which it detached. Here, we present a case of inadvertent stent detachment during stroke treatment for a middle cerebral artery M1 occlusion resulting in progressive thrombosis. The detached stent was removed endovascularly by another Solitaire stent, resulting in the recanalization of the occluded middle cerebral artery.

  18. Iliac Artery Injury Following Placement of the Memotherm Arterial Stent

    SciTech Connect

    Redman, Alan; Cope, Lance; Uberoi, Raman

    2001-03-15

    Iliac rupture and aneurysm formation at the site of stent placement has rarely been described in the literature. We report four cases, three of iliac rupture, including a delayed rupture, and an aneurysm, with the use of a single type of stent, the Memotherm stent. We believe the design of the stent significantly contributed to damage to the arterial wall and subsequently prevented closure of the arterial tear by balloon tamponade in the two cases where this was attempted. Two patients, one with rupture and one with an aneurysm, were successfully treated with a covered stent obviating surgery and two ruptures resulted in death. We recommend that all interventionists carrying out iliac angioplasty and/or stenting should have access to covered stents for such emergencies.

  19. Surface conditioning of 316LVM slotted tube cardiovascular stents.

    PubMed

    Raval, Ankur; Choubey, Animesh; Engineer, Chhaya; Kothwala, Devesh

    2005-01-01

    The surface quality of coronary stents has a significant influence on its biocompatibility. Therefore, surface polishing is of paramount importance in the production and application of stents. In the present study, electropolishing is performed on 316LVM steel slotted tube coronary stents. Additionally, acid pickling, as a pretreatment of electropolishing, is also conducted. Gravimetric analysis of the stents (weight loss and strut width change) in the process of acid pickling and electropolishing are done. Qualitative roughness measurements are made to evaluate the stent surface. Electropolished stents are passivated causing chromium enrichment on the surface of the material, thereby enhancing its corrosion resistance. Passivated and electropolished samples are examined using energy dispersive spectrometry. Balloon expanded and crimped profiles of the passivated stents are qualitatively analyzed.

  20. Everolimus-eluting stents: update on current clinical studies.

    PubMed

    Allocco, Dominic J; Joshi, Anita A; Dawkins, Keith D

    2011-01-01

    Everolimus-eluting stents (EES) have become the most commonly implanted coronary stents worldwide. This review describes and analyzes the clinical data supporting the use of EES, focusing primarily on published, randomized, controlled trials. Everolimus-eluting stents have been shown to have less restenosis, stent thrombosis, and periprocedural myocardial infarction compared with earlier generation paclitaxel-eluting stents (PES). Lower rates of adverse events for EES compared with PES were generally seen in all subgroups, with the notable exception of patients with diabetes mellitus. There have been fewer, randomized, clinical trials comparing EES with either sirolimus-eluting stents or zotarolimus-eluting stents, although very good results with EES have been observed in the trials that have been performed. Recent clinical trial data suggest that this excellent safety and efficacy profile is maintained in a next-generation EES designed to have improved mechanical properties and radiopacity.

  1. Best endoscopic stents for the biliary tree and pancreas.

    PubMed

    Baron, Todd H

    2014-09-01

    To determine trends in pancreaticobiliary stents over the past 12-18 months. Metal biliary stents continue to be used for palliation of malignant distal biliary obstruction with superior patency to plastic stents. The use of covered metal biliary stents is increasingly being used for the management of benign biliary disease. Plastic stents predominate in patients with pancreatic disease, with the exception of transmural drainage of pancreatic necrosis. In both biliary and pancreatic disorders, there is a trend towards greater utilization of endoscopic ultrasound-guided interventions. Endoscopic placement of pancreaticobiliary stents plays an important role in the treatment of complex benign and malignant disease. Further comparative trials are needed to determine the optimal role of endoscopic ultrasound-guided transmural stent placement.

  2. Palliation of Pyloric Stenosis Caused by Gastric Cancer Using an Endoscopically Placed Covered Ultraflex Stent: Covered Stent Inside an Occluded Uncovered Stent

    SciTech Connect

    Nakamura, Toshifumi; Kitagawa, Mutsuo; Takehira, Yasunori; Yamada, Masami; Nishiwaki, Yoshiro; Nakamura, Hirotoshi

    2000-07-15

    A 71-year-old man developed pyloric stenosis caused by gastric cancer. Vomiting and nausea resolved after the insertion of an uncovered Ultraflex stent (length 10 cm, inner diameter 18u23 mm) through a 7-cm-long stenosis, and the patient was able to eat a soft diet. After 6 weeks, stent occlusion occurred due to tumor ingrowth and accumulation of food residue. Endoscopic observation showed a very narrow residual lumen. A covered Ultraflex stent (length 10 cm, inner diameter 18u23 mm) was inserted through the first stent and expanded to its maximum diameter over the next 2 days. The patient's vomiting and nausea improved rapidly. He died 6 months after the second stenting procedure, from metastatic tumor spread, having remained free of nausea and vomiting. In this case, a covered metallic stent prevented tumor ingrowth and maintained gastrointestinal patency.

  3. Treatment of a malignant esophageal fistula with a Gore-Tex-covered flexible nitinol stent

    SciTech Connect

    Kishi, Kazushi; Takeuchi, Taizo; Sonomura, Tetsuo; Kimura, Masashi; Kita, Keisuke; Sato, Morio; Terada, Masaki

    1997-01-15

    In order to treat fistulated esophageal cancer using a flexible stent, a covered flexible stent was constructed by wrapping a nitinol stent with a thin sheet of Gore-Tex, preserving the stents original advantages of flexibility and a low-profile introducer system. This stent was used to perform standard radiotherapy in a case of fistulated esophageal cancer.

  4. Effects of plaque lengths on stent surface roughness.

    PubMed

    Syaifudin, Achmad; Takeda, Ryo; Sasaki, Katsuhiko

    2015-01-01

    The physical properties of the stent surface influence the effectiveness of vascular disease treatment after stent deployment. During the expanding process, the stent acquires high-level deformation that could alter either its microstructure or the magnitude of surface roughness. This paper constructed a finite element simulation to observe the changes in surface roughness during the stenting process. Structural transient dynamic analysis was performed using ANSYS, to identify the deformation after the stent is placed in a blood vessel. Two types of bare metal stents are studied: a Palmaz type and a Sinusoidal type. The relationship between plaque length and the changes in surface roughness was investigated by utilizing three different length of plaque; plaque length longer than the stent, shorter than the stent and the same length as the stent. In order to reduce computational time, 3D cyclical and translational symmetry was implemented into the FE model. The material models used was defined as a multilinear isotropic for stent and hyperelastic for the balloon, plaque and vessel wall. The correlation between the plastic deformation and the changes in surface roughness was obtained by intermittent pure tensile test using specimen whose chemical composition was similar to that of actual stent material. As the plastic strain is achieved from FE simulation, the surface roughness can be assessed thoroughly. The study found that the plaque size relative to stent length significantly influenced the critical changes in surface roughness. It was found that the length of stent which is equal to the plaque length was preferable due to the fact that it generated only moderate change in surface roughness. This effect was less influential to the Sinusoidal stent.

  5. Flow Characteristics Near to Stent Strut Configurations on Femoropopliteal Artery

    NASA Astrophysics Data System (ADS)

    Paisal, Muhammad Sufyan Amir; Fadhil Syed Adnan, Syed; Taib, Ishkrizat; Ismail, Al Emran; Kamil Abdullah, Mohammad; Nordin, Normayati; Seri, Suzairin Md; Darlis, Nofrizalidris

    2017-08-01

    Femoropopiteal artery stenting is a common procedure suggested by medical expert especially for patient who is diagnosed with severe stenosis. Many researchers reported that the growth of stenosis is significantly related to the geometry of stent strut configuration. The different shapes of stent geometry are presenting the different flow pattern and re-circulation in stented femoropopliteal artery. The blood flow characteristics near to the stent geometry are predicted for the possibility of thrombosis and atherosclerosis to be formed as well as increase the growth of stenosis. Thus, this study aims to determine the flow characteristic near to stent strut configuration based on different hemodynamic parameters. Three dimensional models of stent and simplified femoropopliteal artery are modelled using computer aided design (CAD) software. Three different models of stent shapes; hexagon, circle and rectangle are simulated using computational fluid dynamic (CFD) method. Then, parametric study is implemented to predict the performance of stent due to hemodynamic differences. The hemodynamic parameters considered are pressure, velocity, low wall shear stress (WSSlow) and wall shear stress (WSS). From the observation, flow re-circulation has been formed for all simulated stent models which the proximal region shown the severe vortices. However, rectangular shape of stent strut (Type P3) shows the lowest WSSlow and the highest WSS between the range of 4 dyne/cm2 and 70 dyne/cm2. Stent Type P3 also shows the best hemodynamic stent performance as compare to others. In conclusion, Type P3 has a favourable result in hemodynamic stent performance that predicted less probability of thrombosis and atherosclerosis to be formed as well as reduces the growth of restenosis.

  6. The burden of chronic ureteral stenting in cervical cancer survivors

    PubMed Central

    Fan, Yunhua; Jarosek, Stephanie; Elliott, Sean P.

    2017-01-01

    ABSTRACT Purpose Ureteral obstruction in cervical cancer occurs in up to 11% of patients, many of whom undergo ureteral stenting. Our aim was to describe the patient burden of chronic ureteral stenting in a population-based cohort by detailing two objectives: (1) the frequency of repeat procedures for ureteral obstruction; and, (2) the frequency of urinary adverse effects (UAEs) (e.g., lower urinary tract symptoms, flank pain). Materials and Methods From SEER-Medicare, we identified 202 women who underwent ureteral stent placement prior to or following cervical cancer treatment. The frequency of repeat procedures and rate ratios were compared between treatment modalities. The rates and rate ratios of UAEs were compared between our primary cohort (stent + cervical cancer) and the following groups: no stent + cervical cancer, stent + no cancer, and no stent + no cancer. The “no cancer” group was drawn from the 5% Medicare sample. Results 117/202 women (58%) underwent >1 stent procedure. The frequency of additional procedures was significantly higher in patients who received radiation as part of their treatment. UAEs were very common in women with stent + cancer. The rate of UTI was 190 (per 100 person-years), 67 for LUTS, 42 for stones, and 6 for flank pain. These rates were 3-10 fold higher than in the no stent + no cancer control group; rates were also higher than in the no stent + cancer and the stent + no cancer women. Conclusions The burden of disease associated with ureteral stents is higher than expected and urologists should be actively involved in stent management, screening for associated symptoms and offering definitive reconstruction when appropriate. PMID:27649113

  7. Computational simulation of platelet interactions in the initiation of stent thrombosis due to stent malapposition

    NASA Astrophysics Data System (ADS)

    Chesnutt, Jennifer K. W.; Han, Hai-Chao

    2016-02-01

    Coronary stenting is one of the most commonly used approaches to open coronary arteries blocked due to atherosclerosis. Stent malapposition can induce thrombosis but the microscopic process is poorly understood. The objective of this study was to determine the platelet-level process by which different extents of stent malapposition affect the initiation of stent thrombosis. We utilized a discrete element model to computationally simulate the transport, adhesion, and activation of thousands of individual platelets and red blood cells during thrombus initiation in stented coronary arteries. Simulated arteries contained a malapposed stent with a specified gap distance (0, 10, 25, 50, or 200 μm) between the struts and endothelium. Platelet-level details of thrombus formation near the proximal-most strut were measured during the simulations. The relationship between gap distance and amount of thrombus in the artery varied depending on different conditions (e.g., amount of dysfunctional endothelium, shear-induced activation of platelets, and thrombogenicity of the strut). Without considering shear-induced platelet activation, the largest gap distance (200 μm) produced no recirculation and less thrombus than the smallest two gap distances (0 and 10 μm) that created recirculation downstream of the strut. However, with the occurrence of shear-induced platelet activation, the largest gap distance produced more thrombus than the two smallest gap distances, but less thrombus than an intermediate gap distance (25 μm). A large gap distance was not necessarily the most thrombogenic, in contrast to implications of some computational fluid dynamics studies. The severity of stent malapposition affected initial stent thrombosis differently depending on various factors related to fluid recirculation, platelet trajectories, shear stress, and endothelial condition.

  8. Cost-utility analysis of stenting versus endarterectomy in the International Carotid Stenting Study.

    PubMed

    Morris, Stephen; Patel, Nishma V; Dobson, Joanna; Featherstone, Roland L; Richards, Toby; Luengo-Fernandez, Ramon; Rothwell, Peter M; Brown, Martin M

    2016-06-01

    The International Carotid Stenting Study was a multicenter randomized trial in which patients with symptomatic carotid artery stenosis were randomly allocated to treatment by carotid stenting or endarterectomy. Economic evidence comparing these treatments is limited and inconsistent. We compared the cost-effectiveness of stenting versus endarterectomy using International Carotid Stenting Study data. We performed a cost-utility analysis estimating mean costs and quality-adjusted life years per patient for both treatments over a five-year time horizon based on resource use data and utility values collected in the trial. Costs of managing stroke events were estimated using individual patient data from a UK population-based study (Oxford Vascular Study). Mean costs per patient (95% CI) were US$10,477 ($9669 to $11,285) in the stenting group (N = 853) and $9669 ($8835 to $10,504) in the endarterectomy group (N = 857). There were no differences in mean quality-adjusted life years per patient (3.247 (3.160 to 3.333) and 3.228 (3.150 to 3.306), respectively). There were no differences in adjusted costs between groups (mean incremental costs for stenting versus endarterectomy $736 (95% CI -$353 to $1826)) or adjusted outcomes (mean quality-adjusted life years gained -0.010 (95% CI -0.117 to 0.097)). The incremental net monetary benefit for stenting versus endarterectomy was not significantly different from zero at the maximum willingness to pay for a quality-adjusted life year commonly used in the UK. Sensitivity analyses showed little uncertainty in these findings. Economic considerations should not affect whether patients with symptomatic carotid stenosis undergo stenting or endarterectomy. © 2016 World Stroke Organization.

  9. Stenting for pulmonary artery stenosis complicated by univentricular physiology: subanalysis of JPIC stent survey.

    PubMed

    Fujii, Takanari; Tomita, Hideshi; Otsuki, Shinichi; Kobayashi, Toshiki; Ono, Yasuo; Yazaki, Satoshi; Kim, Sung-Hae; Nakanishi, Toshio

    2014-10-01

    Stent implantation is an important treatment option for pulmonary artery stenosis (PS), even if complicated by univentricular physiology (UVP). However, there is paucity of evidence concerning not only its hemodynamic and morphologic indications but also on markers for its optimal target attainment in UVP. The purpose of this study was to evaluate the acute outcome and factors associated with efficacy of stenting for PS complicating UVP. A subanalysis was performed using the data of the Japanese Society of Pediatric Interventional Cardiology (JPIC) stent survey. We analyzed the morphologic and hemodynamic data of 11 patients with UVP who underwent stenting for PS. We defined "a 50% increase in the minimum lumen diameter (MLD)" as "morphologically effective," and "an achievement of 0 mmHg pressure gradient" as "hemodynamically effective." We analyzed the success rate for each criterion and determined factors which may have contributed to hemodynamic effectiveness. Stenting was morphologically effective in all patients, while it was hemodynamically effective in 6/11 (55%). The percent diameter stenosis after stenting was significantly lower in the "hemodynamically effective" group (2.5 ± 5.5% vs 19.6 ± 13.1%, p=0.017). The cutoff value of percent diameter stenosis after stenting to "hemodynamically effective" was 14.6%; the sensitivity was 80% and the specificity was 100% (area under the curve 0.825, p=0.021). The percent diameter stenosis after stenting significantly contributed to achieving a "0 mmHg" pressure gradient, while in order to achieve a "0 mmHg" pressure gradient, the residual percent diameter stenosis should be less than around 15%. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  10. Mechanical Properties of Metallic Stents: How Do These Properties Influence the Choice of Stent for Specific Lesions?

    SciTech Connect

    Dyet, John F.; Watts, William G.; Ettles, Duncan F.; Nicholson, Anthony A.

    2000-01-15

    Purpose: To assess selected balloon-expandable and self-expanding stents for radial force, flexibility, radio-opacity, and trackability, and to relate these physical characteristics to potential indications for placement.Methods: Force-strain curves were plotted for each stent and the force required to produce 50% luminal narrowing was recorded. The ability of the stent to show elastic recoil following deformation was also noted. Flexibility was measured by bending the stents against a force transducer and recording the force required per degree of flexion. Radio-opacity was measured by comparing each stent against a standard aluminum step wedge. Trackability was measured by testing the ability of the stent on its delivery system to track over angles of 90 deg. and 60 deg. Results: The balloon-expandable stents showed greater radial strength and radio-opacity but, apart from the AVE Iliac Bridge stent, showed poorer flexibility and trackability. The self-expanding stents showed less radial force but were able to re-expand following deformity. They were generally more flexible and had better trackability but lower radio-opacity.Conclusion: There is no stent which exhibits all the ideal properties required and therefore the interventionist will need to keep a range of stents available if all lesions are to be addressed.

  11. Magnetic Resonance Angiography of Nonferromagnetic Iliac Artery Stents and Stent-Grafts: A Comparative Study in Sheep

    SciTech Connect

    Schuermann, Karl; Vorwerk, Dierk; Buecker, Arno; Neuerburg, Joerg; Grosskortenhaus, Stefanie; Haage, Patrick; Piroth, Werner; Hunter, David W.; Guenther, Rolf W.

    1999-09-15

    Purpose: To compare nonferromagnetic iliac artery prostheses in their suitability for patency monitoring with magnetic resonance angiography (MRA) using conventional angiography as a reference. Methods: In experiment 1, three Memotherm stents were inserted into the iliac arteries of each of six sheep: two 'tandem' stents on one side and a single stent on the other side. In experiment 2, four prostheses (normal and low-porosity Corvita stent-grafts, Memotherm, ZA-stent) were inserted in each of 11 sheep. Patency was monitored before and 1, 3, and 6 months after insertion with 3D phase-contrast and two 2D time-of-flight sequences (TOF-1: TR/TE = 18/6.9, TOF-2: 13/2.5) with and without contrast at 1.5 T. On 206 coronal MIP images (72 pre-, 134 post-stenting), three readers analyzed 824 iliac segments (206 x 4) for patency and artifacts. Results: There was no difference in the number of artifacts between tandem and single iliac Memotherm stents. The ZA-stent induced significantly fewer artifacts than the other prostheses (p < 0.00001). With MRA, patency of the ZA-stent was correctly diagnosed in 88% of cases, which was almost comparable to nonstented iliac segments (95%), patency of the Memotherm stent in 59%, and of the Corvita stent-grafts in 57% and 55%. The TOF-2 sequence with contrast yielded the best images. Conclusion: MRA compatibility of nonferromagnetic prostheses depends strongly on the design of the device. MRA may be used to monitor the patency of iliac ZA-stents, whereas iliac Memotherm stents and Corvita stent-grafts appear to be less suited for follow-up with MRA.

  12. Carotid Artery Stenting Using a Novel Self-Expanding Braided Nickel-Titanium Stent: Feasibility and Safety Porcine Trial

    SciTech Connect

    Ahlhelm, Frank Kaufmann, Ralf; Ahlhelm, Dirk Ong, Mai Fang; Roth, Christian Reith, Wolfgang

    2009-09-15

    We studied the deliverability and safety of a braided, self-expanding, closed-cell nickel-titanium (NiTi) stent (E-volution, Jotec GmbH, Hechingen, Germany) especially designed for the endovascular treatment of carotid artery bifurcation stenosis with special regard to in-stent stenosis and thrombosis compared with a laser-cut reference nitinol stent in a porcine model of percutaneous vascular interventions. We aimed to assess histopathologic response in minipig carotid and subclavian arteries. Eight minipigs received a total of 42 stents: 14 reference stents and 28 E-volution stents. Eleven of the E-volution stents were additionally coated with heparin. Control angiography was obtained immediately before and after vascular intervention as well as 4 weeks after the procedure. Primary endpoints were 28 days of angiographic analyses as well as histomorphometric analysis, including injury score, inflammation score, luminal diameter, vessel diameter, maximal neointimal thickness, and area of in-stent stenosis. Secondary end points were procedural success, 28-day mortality, and stent thrombosis. All stents could be delivered successfully without procedural complications, morbidity, or mortality during our observation time. As confirmed by histology, no in-stent thrombosis was observed. Compared with common carotid arteries, subclavian arteries are significantly more vulnerable to developing in-stent stenosis caused by neointima proliferation (p < 0.05). Compared with the use of 1 single stent/artery, serial application of two stents leads to a more excessive but not significantly different neointimal proliferation (p > 0.05). The E-volution stent, especially when heparin coated, is in line with the comparison to the laser-cut reference stent displaying similar results of angiographic, histologic, and histomorphometric analyses (p > 0.05). Compared with the reference laser-cut stent, the self-expanding nitinol stent (E-volution) with its advanced braiding technology is

  13. A randomized optical coherence tomography study of coronary stent strut coverage and luminal protrusion with rapamycin-eluting stents.

    PubMed

    Moore, Philip; Barlis, Peter; Spiro, Jonathan; Ghimire, Gopal; Roughton, Michael; Di Mario, Carlo; Wallis, William; Ilsley, Charles; Mitchell, Andrew; Mason, Mark; Kharbanda, Rajesh; Vincent, Peter; Sherwin, Spencer; Dalby, Miles

    2009-05-01

    We used optical coherence tomography, which has a resolution of <20 microm, to analyze thin layers of neointima in rapamycin-eluting coronary stents. Lack of neointimal coverage has been implicated in the pathogenesis of drug-eluting coronary stent thrombosis. Angiography and intracoronary ultrasound lack the resolution to examine this. We conducted a randomized trial in patients receiving polymer-coated rapamycin-eluting stents (Cypher, Cordis, Johnson & Johnson, Miami, Florida) and nonpolymer rapamycin-eluting stents (Yukon, Translumina, Hechingen, Germany) to examine neointimal thickness, stent strut coverage, and protrusion at 90 days. Twenty-four patients (n = 12 for each group) underwent stent deployment and invasive follow-up at 90 days with optical coherence tomography. The primary end point was binary stent strut coverage. Coprimary end points were neointimal thickness and stent strut luminal protrusion. No patient had angiographic restenosis. For polymer-coated and nonpolymer rapamycin-eluting stents, respectively, mean (SD), neointimal thickness was 77.2 (25.6) microm versus 191.2 (86.7) mum (p < 0.001). Binary stent strut coverage was 88.3% (11.8) versus 97.2% (6.1) (p = 0.030). Binary stent strut protrusion was 26.5% (17.5) versus 4.8% (8.6) (p = 0.001). Mean neointimal thickness for the polymer-coated rapamycin-eluting stent was significantly less than the nonpolymer rapamycin-eluting stent but as a result coverage was not homogenous, with >10% of struts being uncovered. High-resolution imaging allowed development of the concept of the protrusion index, and >25% of struts protruded into the vessel lumen with the polymer-coated rapamycin-eluting stent compared with <5% with the nonpolymer rapamycin-eluting stent. These findings may have important implications for the risk of stent thrombosis and, therefore, future stent design. (An optical coherence tomography study to determine stent coverage in polymer coated versus bare metal rapamycin eluting

  14. Functional Nanoarchitectures For Enhanced Drug Eluting Stents

    NASA Astrophysics Data System (ADS)

    Saleh, Yomna E.; Gepreel, Mohamed A.; Allam, Nageh K.

    2017-01-01

    Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile.

  15. Functional Nanoarchitectures For Enhanced Drug Eluting Stents

    PubMed Central

    Saleh, Yomna E.; Gepreel, Mohamed A.; Allam, Nageh K.

    2017-01-01

    Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile. PMID:28079127

  16. Sirolimus-eluting coronary stents: a review

    PubMed Central

    Abizaid, Alexandre

    2007-01-01

    The sirolimus-eluting coronary stent received CE Mark approval in Europe in April 2002. In the US, FDA approval followed in April 2003. Since the preliminary results from the First-in-Man feasibility study were presented, several randomized, controlled trials have documented the profound antiproliferative effects of sirolimus, a macrolide antibiotic and potent cytostatic inhibitor of smooth muscle cell proliferation. Subsequently, the body of clinical evidence was increased by the second wave of evidence from trials in more complex lesions (such as in-stent restenosis, small vessels, chronic total occlusions) and “high-risk” patients such as those with diabetes. More recently we have had the opportunity to compare the two commercially available drug-eluting stents following the presentation of data from six head-to-head trials. As a result of numerous single and multi-center, national and international studies in which the safety and efficacy of sirolimus-eluting coronary stents have been subjected to close scrutiny, the global interventional cardiology community now has a wealth of evidence in support of the use of this technology resulting in dramatically improved patient outcomes after percutaneous intervention. PMID:17580729

  17. Angioplasty and Stenting for Intracranial Stenosis

    PubMed Central

    IZUMI, Takashi; IMAMURA, Hirotoshi; SAKAI, Nobuyuki; MIYACHI, Shigeru

    2014-01-01

    Of the patients enrolled in the Japanese Registry of Neuroendovascular Therapy (JR-NET), a surveillance study in Japanese, 1133 patients who underwent intracranial percutaneous transluminal angioplasty (PTA)/stenting for intracranial stenosis during the period from 2005 to 2009 were investigated. A technical success was achieved in 98.3% of the patients, and 70.5% and 7.5% had a residual stenosis of < 30% and ≥ 50%, respectively. The incidence of ischemic complications and hemorrhagic complications was as low as 7.7% and 2.5%, respectively, but tended to increase in patients who underwent stenting. While a significant correlation with ischemic complications was observed in previously untreated patients and patients who underwent stenting followed by post-dilatation, a significant correlation with hemorrhagic complications was observed in patients who received emergency treatment and those treated between 24 hours and 14 days of the onset. Flexible intracranial stents are expected to contribute to improvement in the treatment outcome. PMID:24390191

  18. Functional Nanoarchitectures For Enhanced Drug Eluting Stents.

    PubMed

    Saleh, Yomna E; Gepreel, Mohamed A; Allam, Nageh K

    2017-01-12

    Different strategies have been investigated to allow for optimum duration and conditions for endothelium healing through the enhancement of coronary stents. In this study, a nanoarchitectured system is proposed as a surface modification for drug eluting stents. Highly oriented nanotubes were vertically grown on the surface of a new Ni-free biocompatible Ti-based alloy, as a potential material for self-expandable stents. The fabricated nanotubes were self-grown from the potential stent substrate, which are also proposed to enhance endothelial proliferation while acting as drug reservoir to hinder Vascular Smooth Muscle Cells (VSMC) proliferation. Two morphologies were synthesized to investigate the effect of structure homogeneity on the intended application. The material was characterized by field-emission scanning electron microscope (FESEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Nanoindentation technique was used to study the mechanical properties of the fabricated material. Cytotoxicity and proliferation studies were performed and compared for the two fabricated nanoarchitectures, versus smooth untextured samples, using in-vitro cultured endothelial cells. Finally, the drug loading capacity was experimentally studied and further supported by computational modeling of the release profile.

  19. Therapeutic potential of active stent coating.

    PubMed

    Wieneke, Heinrich; Schmermund, Axel; von Birgelen, Clemens; Haude, Michael; Erbel, Raimund

    2003-05-01

    Various clinical studies have shown the superiority of stent implantation as compared to conventional balloon angioplasty for the treatment of significant coronary stenosis. However, restenosis remains a major drawback of this interventional technique. Against the background of this serious problem, the concept of stent coating has been developed. In general, coatings can be classified into two types: passive coatings, which only serve as a barrier between the stainless steel, and the tissue and active coatings, which directly interfere with the process of intima proliferation. At this moment, primarily immunosuppressive and cytostatic substances are used as active coatings. Large randomised studies have shown that this novel concept can be successfully implemented into clinical practice. Beside these promising results, studies also revealed potential risks of this new approach. Not only the dosage of the drug but also an optimised kinetic of drug release seem to be essential in preventing restenosis. As with most drugs, the inhibition of neointima proliferation is not restricted to vascular smooth muscle cells but also affects the process of re-endothelialisation, thus we may face a new pitfall of late-stent thrombosis. Although this technique may harbour potential risks, the introduction of stent coating has the potential to dramatically reduce the incidence of restenosis and an exciting chapter in the field of cardiology has been opened.

  20. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... support the vagina and to hold a skin graft after reconstructive surgery. (b) Classification. Class II...

  1. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... support the vagina and to hold a skin graft after reconstructive surgery. (b) Classification. Class II...

  2. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... support the vagina and to hold a skin graft after reconstructive surgery. (b) Classification. Class II...

  3. 21 CFR 884.3900 - Vaginal stent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vaginal stent. 884.3900 Section 884.3900 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... support the vagina and to hold a skin graft after reconstructive surgery. (b) Classification. Class II...

  4. Malignant Ureteral Obstruction: Functional Duration of Metallic versus Polymeric Ureteral Stents

    PubMed Central

    Chow, Po-Ming; Chiang, I-Ni; Chen, Chia-Yen; Huang, Kuo-How; Hsu, Jui-Shan; Wang, Shuo-Meng; Lee, Yuan-Ju; Yu, Hong-Jeng; Pu, Yeong-Shiau; Huang, Chao-Yuan

    2015-01-01

    Background Ureteral obstruction caused by extrinsic compression is often associated with intra-abdominal cancers. Internal drainage with ureteral stents is typically the first-line therapy to relieve such obstructions. Novel designs of ureteral stents made of different materials have been invented to achieve better drainage. In this study, we described the functional outcomes of a Resonance metallic ureteral stent (Cook Medical, Bloomington, Indiana, USA) in patients with malignant ureteral obstruction and compare the functional duration of Resonance stents with regular polymeric stents in the same cohort. Methods Cancer patients who received polymeric stents and subsequent Resonance stents for ureteral obstruction between July 2009 and November 2012 were included in a chart review. Stent failure was detected by clinical symptoms, imaging studies, and renal function tests. The functional durations of each stent were calculated, and possible factors affecting stent patency were investigated. Results A total of 50 stents were successfully inserted into 50 ureteral units in 42 patients with malignant ureteral obstruction. There were 7 antegrade stents and 43 retrograde stents. There were no major complications. Stent-related symptoms were similar in both kinds of stents. After polymeric stents were replaced with Resonance metallic stents, hydronephrosis subsided or remained stable in 90% (45/50) of the ureteral units. Serum creatinine decreased or remained stable in 90% (38/42) of these patients. The Resonance stent exhibited a mean increase in functional duration of 4 months compared with the polymeric stents (p<0.0001), and 50% (25/50) of the Resonance stents exhibited a significant increase in functional duration (more than 3 months). Pre-operative serum creatinine < 2 was associated with a substantial increase in stent duration. Conclusions Resonance stents are effective and safe in relieving malignant ureteral obstructions after polymeric stents failure

  5. Risk factors for proximal migration of biliary tube stents

    PubMed Central

    Kawaguchi, Yoshiaki; Ogawa, Masami; Kawashima, Yohei; Mizukami, Hajime; Maruno, Atsuko; Ito, Hiroyuki; Mine, Tetsuya

    2014-01-01

    AIM: To analyze the risk factors for biliary stent migration in patients with benign and malignant strictures. METHODS: Endoscopic stent placement was performed in 396 patients with bile duct stenosis, at our institution, between June 2003 and March 2009. The indications for bile duct stent implantation included common bile duct stone in 190 patients, malignant lesions in 112, chronic pancreatitis in 62, autoimmune pancreatitis in 14, trauma in eight, surgical complications in six, and primary sclerosing cholangitis (PSC) in four. We retrospectively examined the frequency of stent migration, and analyzed the patient factors (disease, whether endoscopic sphincterotomy was performed, location of bile duct stenosis and diameter of the bile duct) and stent characteristics (duration of stent placement, stent type, diameter and length). Moreover, we investigated retrieval methods for migrated stents and their associated success rates. RESULTS: The frequency of tube stent migration in the total patient population was 3.5%. The cases in which tube stent migration occurred included those with common bile duct stones (3/190; 1.6%), malignant lesions (2/112; 1.8%), chronic pancreatitis (4/62; 6.5%), autoimmune pancreatitis (2/14; 14.3%), trauma (1/8; 12.5%), surgical complications (2/6; 33.3%), and PSC (0/4; 0%). The potential risk factors for migration included bile duct stenosis secondary to benign disease such as chronic pancreatitis and autoimmune pancreatitis (P = 0.030); stenosis of the lower bile duct (P = 0.031); bile duct diameter > 10 mm (P = 0.023); duration of stent placement > 1 mo (P = 0.007); use of straight-type stents (P < 0.001); and 10-Fr sized stents (P < 0.001). Retrieval of the migrated stents was successful in all cases. The grasping technique, using a basket or snare, was effective for pig-tailed or thin and straight stents, whereas the guidewire cannulation technique was effective for thick and straight stents. CONCLUSION: Migration of tube stents

  6. Risk factors for proximal migration of biliary tube stents.

    PubMed

    Kawaguchi, Yoshiaki; Ogawa, Masami; Kawashima, Yohei; Mizukami, Hajime; Maruno, Atsuko; Ito, Hiroyuki; Mine, Tetsuya

    2014-02-07

    To analyze the risk factors for biliary stent migration in patients with benign and malignant strictures. Endoscopic stent placement was performed in 396 patients with bile duct stenosis, at our institution, between June 2003 and March 2009. The indications for bile duct stent implantation included common bile duct stone in 190 patients, malignant lesions in 112, chronic pancreatitis in 62, autoimmune pancreatitis in 14, trauma in eight, surgical complications in six, and primary sclerosing cholangitis (PSC) in four. We retrospectively examined the frequency of stent migration, and analyzed the patient factors (disease, whether endoscopic sphincterotomy was performed, location of bile duct stenosis and diameter of the bile duct) and stent characteristics (duration of stent placement, stent type, diameter and length). Moreover, we investigated retrieval methods for migrated stents and their associated success rates. The frequency of tube stent migration in the total patient population was 3.5%. The cases in which tube stent migration occurred included those with common bile duct stones (3/190; 1.6%), malignant lesions (2/112; 1.8%), chronic pancreatitis (4/62; 6.5%), autoimmune pancreatitis (2/14; 14.3%), trauma (1/8; 12.5%), surgical complications (2/6; 33.3%), and PSC (0/4; 0%). The potential risk factors for migration included bile duct stenosis secondary to benign disease such as chronic pancreatitis and autoimmune pancreatitis (P = 0.030); stenosis of the lower bile duct (P = 0.031); bile duct diameter > 10 mm (P = 0.023); duration of stent placement > 1 mo (P = 0.007); use of straight-type stents (P < 0.001); and 10-Fr sized stents (P < 0.001). Retrieval of the migrated stents was successful in all cases. The grasping technique, using a basket or snare, was effective for pig-tailed or thin and straight stents, whereas the guidewire cannulation technique was effective for thick and straight stents. Migration of tube stents within the bile duct is rare but

  7. Economic analysis of esophageal stenting for management of malignant dysphagia.

    PubMed

    Rao, C; Haycock, A; Zacharakis, E; Krasopoulos, G; Yakoub, D; Protopapas, A; Darzi, A; Hanna, G B; Athanasiou, T

    2009-01-01

    Over half of patients diagnosed with esophageal cancer are unsuitable for curative resection. A significant proportion of these patients will subsequently require palliative stenting to alleviate dysphagia. There is growing consensus in the literature that the deployment of a Self-Expanding Metal Stent is the optimum stenting strategy; however, it remains unclear whether covered or uncovered metal stents are more cost-effective. In order to determine which type of prosthesis is more cost-effective, we compared the different stenting strategies in terms of 1-year stent-related mortality, health-related quality of life, and cost. A decision analytical model was constructed to compare the 1-year stent-related mortality, health-related quality of life, and cost between covered and uncovered stents. Probabilistic sensitivity analysis was performed to quantify the uncertainty associated with our results. Value of Information analysis was performed to assess the value of further research. In order to fully characterize the uncertainty associated with this decision, plastic stents were included in our analysis. Stent-related mortality was slightly lower following covered stent deployment compared with uncovered stent deployment (1.00% vs. 1.26%). Covered stents were more effective by 0.0013 Quality-Adjusted Life Years (Standard Deviation [SD] 0.0013 Quality-Adjusted Life Years). They were also less expensive by $729.58 (SD $390.63). Probabilistic sensitivity analysis suggested that these results were not sensitive to model parameter uncertainty. Plastic stents deployment was $2832.64 (SD $1182.72) more expensive than uncovered metal stent deployment. Value of Information analysis suggests that the maximum value of further research in the UK is $61,124.30. The results of this study represent strong evidence for the cost-effectiveness of covered compared with uncovered self-expanding metal stents for the palliation of patients with malignant dysphagia. The findings support

  8. Comparison of Self-Expanding Polyethylene Terephthalate and Metallic Stents Implanted in Porcine Iliac Arteries

    SciTech Connect

    Wilczek, Krzysztof; Scheerder, Ivan de; Wang Kai; Verbeken, Eric; Piessens, Jan

    1996-05-15

    Purpose: Comparison of the biocompatibility of self-expanding polyethylene terephthalate (PET) stents with self-expanding metallic stents (Wallstents). Methods: Diameter- and length-matched PET stents and Wallstents were symmetrically implanted in the paired iliac arteries of 13 crossbred domestic swine. Stent deployment was studied angiographically and with intravascular ultrasound immediately after stent implantation. The angiographic stented lumen diameter was measured using quantitative vessel analysis before, immediately after stenting, and at 6-week follow-up. Cross-section histopathology and area morphometry were performed. Results: Immediately poststenting, intravascular ultrasound revealed proximal dislocation of 5 of the 13 PET stents, whereas all metal stents were firmly embedded at the implantation site. At 6-week follow-up, three of the remaining PET stents were totally or subtotally occluded by organized thrombus, whereas all metal stents were patent. Compared with immediately poststenting, the angiographic lumen diameter within the five remaining PET stents was reduced by 30%, and that of the metallic stents was virtually unaltered (p < 0.02). This observation was confirmed by postmortem morphometry, wherein the PET-stented vessel segments a diameter stenosis of 40% was measured vs only 9% in the metallic stents (p < 0.0001). Conclusion: PET-stent deployment is difficult to control due to the lack of radiopacity of this stent. PET stents seem to be more thrombogenic and lead to significantly more neointimal proliferation than metallic stents.

  9. Computational design analysis for deployment of cardiovascular stents

    NASA Astrophysics Data System (ADS)

    Tammareddi, Sriram; Sun, Guangyong; Li, Qing

    2010-06-01

    Cardiovascular disease has become a major global healthcare problem. As one of the relatively new medical devices, stents offer a minimally-invasive surgical strategy to improve the quality of life for numerous cardiovascular disease patients. One of the key associative issues has been to understand the effect of stent structures on its deployment behaviour. This paper aims to develop a computational model for exploring the biomechanical responses to the change in stent geometrical parameters, namely the strut thickness and cross-link width of the Palmaz-Schatz stent. Explicit 3D dynamic finite element analysis was carried out to explore the sensitivity of these geometrical parameters on deployment performance, such as dog-boning, fore-shortening, and stent deformation over the load cycle. It has been found that an increase in stent thickness causes a sizeable rise in the load required to deform the stent to its target diameter, whilst reducing maximum dog-boning in the stent. An increase in the cross-link width showed that no change in the load is required to deform the stent to its target diameter, and there is no apparent correlation with dog-boning but an increased fore-shortening with increasing cross-link width. The computational modelling and analysis presented herein proves an effective way to refine or optimise the design of stent structures.

  10. Are bio-absorbable stents the future of SFA treatment?

    PubMed

    Peeters, P; Keirse, K; Verbist, J; Deloose, K; Bosiers, M

    2010-02-01

    Several limitations inherent to the implantation of a metallic device, such as the occurrence of in-stent re-stenosis, in an arterial lumen intuitively explain the interest for developing bio-absorbable stents. Two main types of bio-absorbable stents currently exist: polymer stents and metallic stents. To date, no studies with bio-absorbable stents have been conducted in the superficial femoral artery (SFA). Because of their strut thickness and lack of radial force, polymer stents are no good candidates for endovascular use. Absorbable metal stents (AMS) do have the potential to perform well for artery treatment, although current evidence from in-human coronary and infrapopliteal studies yield unsatisfactory results. Drastic technological improvements are mandatory before AMS can be considered for every day practice. Yet, it is our belief that further development of other metal and non-metal bio-absorbable stents, with or without drug-coating, may lead to the creation of the ultimate SFA stent.

  11. [Biodegradable coronary stents: history of application and own experience].

    PubMed

    Furkalo, S N; Khasianov, I V; Vlasenko, E A

    2014-10-01

    Experience of application of a new generation coronary stents--biodegradable stent--platforms--was summarized, in 46 patients, suffering an ischemic heart disease, 60 stents "Absorb" were implanted. Unstable course of the disease was noted in 6 (13.0%) patients, coronary angina of functional class II--III--in 40 (87%). Early stenting was accomplished in 10, aortocoronary shunting--in 4 patients, and abdominal aorta endoprosthesis--in 1. One stent "Absorb" was implanted to 33 patients, two stents--to 11, four biodegradable stents--1. In one observation the stenting of coronary arteries and a. carotis interna was conducted. In all the patients the immediate postoperative period course was uneventful, unfaithful implantation or an acute thrombosis of stent were not observed. The investigation results witnesses the possibility of application of this technology in various clinical and angiographic situations. For wide introduction of biodegradable stents into practice of interventional cardiology departments it is necessary to proceed with the immediate and late follow-up results studying.

  12. Biodegradable Airway Stents - Bench to Bedside: A Comprehensive Review.

    PubMed

    Dutau, Hervé; Musani, Ali Imran; Laroumagne, Sophie; Darwiche, Kaid; Freitag, Lutz; Astoul, Philippe

    2015-01-01

    Airway stents are indicated to treat symptomatic narrowing or to close fistulas of the central airways. They are generally divided into two types: the silicone stents and the metallic stents. Unlike in malignancies, removability is a major objective of temporary stenting in benign conditions, which poses the challenge of a new rigid bronchoscopic procedure under general anesthesia and stent removal with all its attendant risks and costs. The concept of a biodegradable (BD) stent that could maintain the patency of an airway for a predetermined duration of time is very appealing. These BD stents would gradually degrade and eventually vanish from the airway once they are no longer needed. Such stents are currently an area of intense research. Another very promising concept of drug delivery with such stents is also a very exciting area of current research. The aim of this comprehensive review is to discuss all pertinent available literature on the use of BD materials in various clinical applications and to extensively review all animal and humans trials involving BD airway stents. © 2015 S. Karger AG, Basel.

  13. Drug- and Gene-eluting Stents for Preventing Coronary Restenosis

    PubMed Central

    Lekshmi, Kamali Manickavasagam; Che, Hui-Lian; Cho, Chong-Su

    2017-01-01

    Coronary artery disease (CAD) has been reported to be a major cause of death worldwide. Current treatment methods include atherectomy, coronary angioplasty (as a percutaneous coronary intervention), and coronary artery bypass. Among them, the insertion of stents into the coronary artery is one of the commonly used methods for CAD, although the formation of in-stent restenosis (ISR) is a major drawback, demanding improvement in stent technology. Stents can be improved using the delivery of DNA, siRNA, and miRNA rather than anti-inflammatory/anti-thrombotic drugs. In particular, genes that could interfere with the development of plaque around infected regions are conjugated on the stent surface to inhibit neointimal formation. Despite their potential benefits, it is necessary to explore the various properties of gene-eluting stents. Furthermore, multifunctional electronic stents that can be used as a biosensor and deliver drug- or gene-based on physiological condition will be a very promising way to the successful treatment of ISR. In this review, we have discussed the molecular mechanism of restenosis, the use of drug- and gene-eluting stents, and the possible roles that these stents have in the prevention and treatment of coronary restenosis. Further, we have explained how multifunctional electronic stents could be used as a biosensor and deliver drugs based on physiological conditions. PMID:28184335

  14. Stabilization of Coronary Stents Using the Floating-Wire Technique.

    PubMed

    Li, Yue; Xue, Jingyi; Li, Shuang; Sheng, Li; Sun, Danghui; Li, Weimin; Gong, Yongtai

    2015-11-01

    Excessive movement of coronary stents within the artery can make accurate stent placement difficult. This study assessed the use of the floating-wire technique to reduce stent motion to improve placement accuracy. During percutaneous coronary intervention, if excessive stent movement prevented accurate stent placement, the floating-wire technique was performed to reduce stent motion within the coronary artery during both stent positioning and deployment. Postprocedural angiograms were analyzed by two independent operators to measure the motion length of the stent delivery system relative to the coronary artery before and after using the floating-wire technique. The floating-wire technique was considered necessary in 19 patients. No procedural complications occurred. The extent of motion was markedly reduced by using the floating-wire technique (4.04 ± 1.25 mm to 1.11 ± 0.81 mm; P<.001). The floating-wire technique is an effective and safe method to reduce stent movement and facilitate accurate stent deployment. This simple technique can be easily applied in any interventional cardiac catheterization laboratory without the need for additional training or equipment.

  15. Thin film nitinol covered stents: design and animal testing.

    PubMed

    Levi, Daniel S; Williams, Ryan J; Liu, Jasen; Danon, Saar; Stepan, Lenka L; Panduranga, Mohanchandra K; Fishbein, Michael C; Carman, Greg P

    2008-01-01

    Interventionalists in many specialties have the need for improved, low profile covered stents. Thin films of nitinol (<5-10 microns) could be used to improve current covered stent technology. A "hot target" sputter deposition technique was used to create thin films of nitinol for this study. Covered stents were created from commercially available balloon-inflatable and self-expanding stents. Stents were deployed in a laboratory flow loop and in four swine. Uncovered stent portions served as controls. Postmortem examinations were performed 2-6 weeks after implantation. In short-term testing, thin film nitinol covered stents deployed in the arterial circulation showed no intimal proliferation and were easily removed from the arterial wall postmortem. Scanning electron microscopy showed a thin layer of endothelial cells on the thin film, which covered the entire film by 3 weeks. By contrast, significant neointimal hyperplasia occurred on the luminal side of stents deployed in the venous circulation. Extremely low-profile covered stents can be manufactured using thin films of nitinol. Although long-term studies are needed, thin film nitinol may allow for the development of low-profile, nonthrombogenic covered stents.

  16. Stents: Biomechanics, Biomaterials, and Insights from Computational Modeling.

    PubMed

    Karanasiou, Georgia S; Papafaklis, Michail I; Conway, Claire; Michalis, Lampros K; Tzafriri, Rami; Edelman, Elazer R; Fotiadis, Dimitrios I

    2017-04-01

    Coronary stents have revolutionized the treatment of coronary artery disease. Improvement in clinical outcomes requires detailed evaluation of the performance of stent biomechanics and the effectiveness as well as safety of biomaterials aiming at optimization of endovascular devices. Stents need to harmonize the hemodynamic environment and promote beneficial vessel healing processes with decreased thrombogenicity. Stent design variables and expansion properties are critical for vessel scaffolding. Drug-elution from stents, can help inhibit in-stent restenosis, but adds further complexity as drug release kinetics and coating formulations can dominate tissue responses. Biodegradable and bioabsorbable stents go one step further providing complete absorption over time governed by corrosion and erosion mechanisms. The advances in computing power and computational methods have enabled the application of numerical simulations and the in silico evaluation of the performance of stent devices made up of complex alloys and bioerodible materials in a range of dimensions and designs and with the capacity to retain and elute bioactive agents. This review presents the current knowledge on stent biomechanics, stent fatigue as well as drug release and mechanisms governing biodegradability focusing on the insights from computational modeling approaches.

  17. Recanalization Results After Intracranial Stenting of Atherosclerotic Stenoses

    SciTech Connect

    Blasel, Stella Yuekzek, Zeynep; Kurre, Wiebke; Berkefeld, Joachim; Neumann-Haefelin, Tobias; Hattingen, Elke; Mesnil de Rochemont, Richard du

    2010-10-15

    The purpose of this investigation was to provide a detailed description of the angiographic results after stenting of high-grade intracranial stenosis using balloon-expandable stents. Forty consecutive patients with symptomatic atherosclerotic intracranial stenosis >50% received endovascular treatment by placement of balloon-expandable stents using the concept of slight underdilation and strict avoidance of overdilation. Intra-arterial digital subtraction angiography images before and after stenting in the same projection were reviewed for pre- and post-therapeutic measurement of the degree of stenosis and evaluation of morphologic criteria like plaque coverage, stent apposition, patency of side branches, and signs of dissection or vasospasm. Stenting decreased the mean percentage stenosis from 76.2 (WASID criteria) to 20.8%. Residual stenosis ranged from 0 to 55% with residual stenosis >50% in two of 40 cases. Technical success rate was 95%. There were no major vessel complications, but minor abnormalities like incomplete stent apposition (8/40) or plaque coverage (7/40), incomplete filling of side branches (13/40), and minor dissections after stenting (2/40) were seen. One case with incomplete stent apposition and two cases with side branch compromise were associated with clinical symptoms. In conclusion, intracranial stenting with slight underdilation avoided major vessel complication and created reliable luminal gain. Suboptimal recanalization results were frequently detected and may be the source of neurological complications in individual cases.

  18. Computational Analysis on Stent Geometries in Carotid Artery: A Review

    NASA Astrophysics Data System (ADS)

    Paisal, Muhammad Sufyan Amir; Taib, Ishkrizat; Ismail, Al Emran

    2017-01-01

    This paper reviews the work done by previous researchers in order to gather the information for the current study which about the computational analysis on stent geometry in carotid artery. The implantation of stent in carotid artery has become popular treatment for arterial diseases of hypertension such as stenosis, thrombosis, atherosclerosis and embolization, in reducing the rate of mortality and morbidity. For the stenting of an artery, the previous researchers did many type of mathematical models in which, the physiological variables of artery is analogized to electrical variables. Thus, the computational fluid dynamics (CFD) of artery could be done, which this method is also did by previous researchers. It lead to the current study in finding the hemodynamic characteristics due to artery stenting such as wall shear stress (WSS) and wall shear stress gradient (WSSG). Another objective of this study is to evaluate the nowadays stent configuration for full optimization in reducing the arterial side effect such as restenosis rate after a few weeks of stenting. The evaluation of stent is based on the decrease of strut-strut intersection, decrease of strut width and increase of the strut-strut spacing. The existing configuration of stents are actually good enough in widening the narrowed arterial wall but the disease such as thrombosis still occurs in early and late stage after the stent implantation. Thus, the outcome of this study is the prediction for the reduction of restenosis rate and the WSS distribution is predicted to be able in classifying which stent configuration is the best.

  19. CT Imaging of Coronary Stents: Past, Present, and Future

    PubMed Central

    Mahnken, Andreas H.

    2012-01-01

    Coronary stenting became a mainstay in coronary revascularization therapy. Despite tremendous advances in therapy, in-stent restenosis (ISR) remains a key problem after coronary stenting. Coronary CT angiography evolved as a valuable tool in the diagnostic workup of patients after coronary revascularization therapy. It has a negative predictive value in the range of 98% for ruling out significant ISR. As CT imaging of coronary stents depends on patient and stent characteristics, patient selection is crucial for success. Ideal candidates have stents with a diameter of 3 mm and more. Nevertheless, even with most recent CT scanners, about 8% of stents are not accessible mostly due to blooming or motion artifacts. While the diagnosis of ISR is currently based on the visual assessment of the stent lumen, functional information on the hemodynamic significance of in-stent stenosis became available with the most recent generation of dual source CT scanners. This paper provides a comprehensive overview on previous developments, current techniques, and clinical evidence for cardiac CT in patients with coronary artery stents. PMID:22997590

  20. Microguidewire Looping to Traverse Stented Parent Arteries of Intracranial Aneurysms

    PubMed Central

    Cho, Young Dae; Rhim, Jong Kook; Yoo, Dong Hyun; Kang, Hyun-Seung; Kim, Jeong Eun; Han, Moon Hee

    2017-01-01

    Objective Stents are widely used in coil embolization of intracranial aneurysms, but on occasion, a microcatheter must traverse a stented segment of artery (so-called trans-cell technique) to select an aneurysm, or double stenting may necessary. In such situations, microguidewire passage and microcatheter delivery through a tortuous stented parent artery may pose a technical challenge. Described herein is a microguidewire looping technique to facilitate endovascular navigation in these circumstances. Methods To apply this technique, the microguidewire tip is looped before entering the stented parent artery and then advanced distally past the stented segment, with the loop intact. Rounding of the tip prevents interference from stent struts during passage. A microcatheter is subsequently passed into the stented artery for positioning near the neck of aneurysm, with microguidewire assistance. The aneurysm is then selected, steering the microcatheter tip (via inner microguidewire) into the dome. Results This technique proved successful during coil embolization of nine saccular intracranial aneurysms (internal carotid artery [ICA], 6; middle cerebral artery, 2; basilar tip, 1), performing eight trans-cell deliveries and one additional stenting. Selective endovascular embolization was enabled in all patients, resulting in excellent clinical and radiologic outcomes, with no morbidity or mortality directly attributable to microguidewire looping. Conclusion Microguidewire looping is a reasonable alternative if passage through a stented artery is not feasible by traditional means, especially at paraclinoid ICA sites. PMID:28264249

  1. Forgotten ureteric stents in renal transplant recipients: three case reports.

    PubMed

    Bardapure, Mallikarjun; Sharma, Ajay; Hammad, Abdul

    2014-01-01

    Ureteric stents are widely used in renal transplantation to minimize the early urological complications. Ureteric stents are removed between two and 12 weeks following trans-plantation, once the vesico-ureteric anastomosis is healed. Ureteric stents are associated with considerable morbidity due to complications such as infection, hematuria, encrustations and migration. Despite the patient having a regular follow-up in the renal transplant clinic, ureteric stents may be overlooked and forgotten. The retained or forgotten ureteric stents may adversely affect renal allograft function and could be potentially life-threatening in immunocompromised transplant recipients with a single transplant kidney. Retrieving these retained ureteric stents could be challenging and may necessitate multimodal urological treatments. We report three cases of forgotten stents in renal transplant recipients for more than four years. These cases emphasize the importance of patient education about the indwelling ureteric stent and possibly providing with a stent card to the patient. Maintaining a stent register, with a possible computer tracking system, is highly recommended to prevent such complications.

  2. Ferromagnetic Bare Metal Stent for Endothelial Cell Capture and Retention

    PubMed Central

    Uthamaraj, Susheil; Tefft, Brandon J.; Hlinomaz, Ota; Sandhu, Gurpreet S.; Dragomir-Daescu, Dan

    2015-01-01

    Rapid endothelialization of cardiovascular stents is needed to reduce stent thrombosis and to avoid anti-platelet therapy which can reduce bleeding risk. The feasibility of using magnetic forces to capture and retain endothelial outgrowth cells (EOC) labeled with super paramagnetic iron oxide nanoparticles (SPION) has been shown previously. But this technique requires the development of a mechanically functional stent from a magnetic and biocompatible material followed by in-vitro and in-vivo testing to prove rapid endothelialization. We developed a weakly ferromagnetic stent from 2205 duplex stainless steel using computer aided design (CAD) and its design was further refined using finite element analysis (FEA). The final design of the stent exhibited a principal strain below the fracture limit of the material during mechanical crimping and expansion. One hundred stents were manufactured and a subset of them was used for mechanical testing, retained magnetic field measurements, in-vitro cell capture studies, and in-vivo implantation studies. Ten stents were tested for deployment to verify if they sustained crimping and expansion cycle without failure. Another 10 stents were magnetized using a strong neodymium magnet and their retained magnetic field was measured. The stents showed that the retained magnetism was sufficient to capture SPION-labeled EOC in our in-vitro studies. SPION-labeled EOC capture and retention was verified in large animal models by implanting 1 magnetized stent and 1 non-magnetized control stent in each of 4 pigs. The stented arteries were explanted after 7 days and analyzed histologically. The weakly magnetic stents developed in this study were capable of attracting and retaining SPION-labeled endothelial cells which can promote rapid healing. PMID:26436434

  3. Acquired aortic atresia: Catheter therapy using covered stents.

    PubMed

    Momenah, Tarek S; Khan, Muhammad A; Qureshi, Shakeel; Hijazi, Ziyad M

    2015-11-15

    To maintain aortic continuity, aortic arch interruption is usually treated surgically. We present our experience of aortic arch reconstruction using percutaneous implantation of covered stents and mid-term follow-up. To describe the feasibility, safety, and effectiveness using percutaneous placement of covered stents for functional aortic atresia and mid-term follow-up. Nine patients (7 males), mean age of 30.8 ±16.2 years (range 13-58 years) and mean body weight of 65.7± 14.9 kg (range 52-95 kg), were investigated for systemic hypertension and found to have functional aortic interruption. All were treated with percutaneous perforation, combined with balloon dilation and implantation of covered stents. After stent implantation, control angiograms were performed. All the patients had functional aortic interruption and continuity was established by perforating the atretic segment with trans-septal Brockenbrough needle or the stiff end of a guide wire. A covered Cheatham-Platinum CP stent was used to establish the luminal continuity of the aortic arch. Angiograms after stent deployment showed good forward flow through the stent and hemodynamic assessment revealed minimal gradients across the stent. The mean invasive descending aortic systolic blood pressure before stenting was 86.6 ± 14.3 mm Hg, which increased to 116.5 ± 16.3 mm Hg, after stenting (P = 0.004). The mean invasive descending aortic diastolic blood pressure before stenting was 63.6 ± 8.1 mm Hg, which increased to 79.7 ± 13.3 mm Hg after stenting (P = 0.002). Percutaneous treatment of functional aortic atresia with covered stents is feasible, safe, and effective alternative to surgery with excellent short- and mid-term results. © 2015 Wiley Periodicals, Inc.

  4. Stent-Protected Carotid Angioplasty Using a Membrane Stent: A Comparative Cadaver Study

    SciTech Connect

    Mueller-Huelsbeck, Stefan Guehne, Albrecht; Tsokos, Michael; Huesler, Erhard J.; Schaffner, Silvio R.; Paulsen, Friedrich; Hedderich, Juergen; Heller, Martin; Jahnke, Thomas

    2006-08-15

    Purpose. To evaluate the performance of a prototype membrane stent, MembraX, in the prevention of acute and late embolization and to quantify particle embolization during carotid stent placement in human carotid explants in a proof of concept study. Methods. Thirty human carotid cadaveric explants (mild stenoses 0-29%, n = 23; moderate stenoses 30-69%, n = 3; severe stenoses 70-99%, n = 2) that included the common, internal and external carotid arteries were integrated into a pulsatile-flow model. Three groups were formed according to the age of the donors (mean 58.8 years; sample SD 15.99 years) and randomized to three test groups: (I) MembraX, n 9; (II) Xpert bare stent, n = 10; (III) Xpert bare stent with Emboshield protection device, n = 9. Emboli liberated during stent deployment (step A), post-dilatation (step B), and late embolization (step C) were measured in 100 {mu}m effluent filters. When the Emboshield was used, embolus penetration was measured during placement (step D) and retrieval (step E). Late embolization was simulated by compressing the area of the stented vessel five times. Results. Absolute numbers of particles (median; >100 {mu}m) caught in the effluent filter were: (I) MembraX: A = 7, B = 9, C = 3; (II) bare stent: A 6.5, B = 6, C = 4.5; (III) bare stent and Emboshield: A = 7, B = 7, C.=.5, D = 8, E = 10. The data showed no statistical differences according to whether embolic load was analyzed by weight or mean particle size. When summing all procedural steps, the Emboshield caused the greatest load by weight (p 0.011) and the largest number (p = 0.054) of particles. Conclusions. On the basis of these limited data neither a membrane stent nor a protection device showed significant advantages during ex vivo carotid angioplasty. However, the membrane stent seems to have the potential for reducing the emboli responsible for supposed late embolization, whereas more emboli were observed when using a protection device. Further studies are necessary

  5. Carotid Artery Stenting 2013: Thumbs up

    PubMed Central

    Wagdi, Philipp

    2013-01-01

    It has been customary for interventional cardiologists involved in carotid artery stenting, to underline non-inferiority of the percutaneous technique versus surgical carotid endarterectomy. To that end, all cause morbidity and mortality figures of both methods are compared. Surgery has, in most large randomized studies, had an edge over stenting in terms of cerebrovascular adverse events. This may have partly been due to occasional indiscriminate indication for stenting in lesions and/or vessels with unfavourable characteristics (severe target vessel tortuosity and calcification, Type III aortic arch, and so on). On one hand, the author pleads for improvement of the excellent results of endarterectomy, by subjecting all patients planned for surgery to a thorough preoperative cardiological work up, including generous invasive investigation, thus reducing the incidence of perioperative myocardial infarction, heart failure and cardiac death. On the other hand, we are convinced that the results of carotid stenting should then be compared to best practice surgery. The rate of neurological adverse event rate after carotid endarterectomy at our institution lies under 0.7% at 30 days postoperatively. Specifically, the goal should be that carotid stenting underbids surgical endarterectomy, also and mainly, in terms of cerebral and cerebrovascular adverse events. Cardiac morbidity and mortality as well as laryngeal nerve palsy should no more be the main arguments for the percutaneous approach. This should easily be possible if patient selection for carotid revascularisation would be approached according to morphological criteria, in analogy with the “Syntax”-score used to optimise revascularisation strategies in coronary artery disease.

  6. Drug-eluting stents versus bare-metal stents for acute coronary syndrome.

    PubMed

    Feinberg, Joshua; Nielsen, Emil Eik; Greenhalgh, Janette; Hounsome, Juliet; Sethi, Naqash J; Safi, Sanam; Gluud, Christian; Jakobsen, Janus C

    2017-08-23

    Approximately 3.7 million people died from acute coronary syndrome worldwide in 2012. Acute coronary syndrome, also known as myocardial infarction or unstable angina pectoris, is caused by a sudden blockage of the blood supplied to the heart muscle. Percutaneous coronary intervention is often used for acute coronary syndrome, but previous systematic reviews on the effects of drug-eluting stents compared with bare-metal stents have shown conflicting results with regard to myocardial infarction; have not fully taken account of the risk of random and systematic errors; and have not included all relevant randomised clinical trials. To assess the benefits and harms of drug-eluting stents versus bare-metal stents in people with acute coronary syndrome. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS, SCI-EXPANDED, and BIOSIS from their inception to January 2017. We also searched two clinical trials registers, the European Medicines Agency and the US Food and Drug Administration databases, and pharmaceutical company websites. In addition, we searched the reference lists of review articles and relevant trials. Randomised clinical trials assessing the effects of drug-eluting stents versus bare-metal stents for acute coronary syndrome. We included trials irrespective of publication type, status, date, or language. We followed our published protocol and the methodological recommendations of Cochrane. Two review authors independently extracted data. We assessed the risks of systematic error by bias domains. We conducted Trial Sequential Analyses to control the risks of random errors. Our primary outcomes were all-cause mortality, major cardiovascular events, serious adverse events, and quality of life. Our secondary outcomes were angina, cardiovascular mortality, and myocardial infarction. Our primary assessment time point was at maximum follow-up. We assessed the quality of the evidence by the GRADE approach. We included 25

  7. Direct coronary stent implantation: safety, feasibility, and predictors of success of the strategy of direct coronary stent implantation.

    PubMed

    Laarman, G; Muthusamy, T S; Swart, H; Westendorp, I; Kiemeneij, F; Slagboom, T; van der Wieken, R

    2001-04-01

    This prospective study was designed to evaluate the feasibility, safety, predictive factors of success, and 6-month follow-up of stent implantation without balloon predilatation (direct stenting) in 250 patients undergoing elective stent implantation. Balloon dilatation prior to stent implantation was a prerequisite to facilitate passage and deployment of the stent. Stent technology has changed tremendously, resulting in stents with improved properties, which may allow stent placement without prior balloon dilatation. Patients with coronary lesions suitable for elective stent implantation were included in this trial. Coronary interventions were undertaken predominantly via the transradial route using 6 Fr guiding catheters. Direct stent implantation was attempted using AVE GFX II coronary stent delivery systems. Upon failure, predilatation was undertaken before reattempting stent implantation. Patient data and ECGs were obtained from case records and from personal or telephone interviews 6 months after the procedure. Values were presented as mean +/- standard deviation. Student's t-test, two-tailed at 5% level of significance, was used to compare the difference of two means. Multivariate logistic regression analysis was performed to establish predictive factors for failure of direct stenting. Two hundred and sixty-six direct stent implantations were attempted in 250 patients. Direct stenting was successful in 226 (85%) cases. Out of 40(15%) cases where direct stenting failed, balloon predilatation facilitated stent implantation in 39. In one lesion, stent implantation was not possible despite adequate predilatation. Predictive factors for failure of direct stenting on multivariate analysis were LCx lesions (P < 0.01), complex lesions (P < 0.01), and longer stents (P < 0.001). Minimal luminal diameter and percentage diameter stenosis of lesions in the successful and the failure group were not significantly different (0.94 +/- 0.39 mm vs. 0.84 +/- 0.41 mm, P = NS

  8. Interval Biliary Stent Placement Via Percutaneous Ultrasound Guided Cholecystostomy: Another Approach to Palliative Treatment in Malignant Biliary Tract Obstruction

    SciTech Connect

    Harding, James Mortimer, Alex; Kelly, Michael; Loveday, Eric

    2010-12-15

    Percutaneous cholecystostomy is a minimally invasive procedure for providing gallbladder decompression, often in critically ill patients. It can be used in malignant biliary obstruction following failed endoscopic retrograde cholangiopancreatography when the intrahepatic ducts are not dilated or when stent insertion is not possible via the bile ducts. In properly selected patients, percutaneous cholecystostomy in obstructive jaundice is a simple, safe, and rapid option for biliary decompression, thus avoiding the morbidity and mortality involved with percutaneous transhepatic biliary stenting. Subsequent use of a percutaneous cholecystostomy for definitive biliary stent placement is an attractive concept and leaves patients with no external drain. To the best of our knowledge, it has only been described on three previous occasions in the published literature, on each occasion forced by surgical or technical considerations. Traditionally, anatomic/technical considerations and the risk of bile leak have precluded such an approach, but improvements in catheter design and manufacture may now make it more feasible. We report a case of successful interval metal stent placement via percutaneous cholecystostomy which was preplanned and achieved excellent palliation for the patient. The pros and cons of the procedure and approach are discussed.

  9. Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model

    PubMed Central

    Kim, J H; Shin, J H; Shin, D H; Moon, M-W; Park, K; Kim, T-H; Shin, K M; Won, Y H; Han, D K; Lee, K-R

    2011-01-01

    Objective Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility. Methods A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8). Results The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01). Conclusion Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent. PMID:21325363

  10. Comparison of diamond-like carbon-coated nitinol stents with or without polyethylene glycol grafting and uncoated nitinol stents in a canine iliac artery model.

    PubMed

    Kim, J H; Shin, J H; Shin, D H; Moon, M-W; Park, K; Kim, T-H; Shin, K M; Won, Y H; Han, D K; Lee, K-R

    2011-03-01

    Neointimal hyperplasia is a major complication of endovascular stent placement with consequent in-stent restenosis or occlusion. Improvements in the biocompatibility of stent designs could reduce stent-associated thrombosis and in-stent restenosis. We hypothesised that the use of a diamond-like carbon (DLC)-coated nitinol stent or a polyethylene glycol (PEG)-DLC-coated nitinol stent could reduce the formation of neointimal hyperplasia, thereby improving stent patency with improved biocompatibility. A total of 24 stents were implanted, under general anaesthesia, into the iliac arteries of six dogs (four stents in each dog) using the carotid artery approach. The experimental study dogs were divided into three groups: the uncoated nitinol stent group (n = 8), the DLC-nitinol stent group (n = 8) and the PEG-DLC-nitinol stent group (n = 8). The mean percentage of neointimal hyperplasia was significantly less in the DLC-nitinol stent group (26.7±7.6%) than in the nitinol stent group (40.0±20.3%) (p = 0.021). However, the mean percentage of neointimal hyperplasia was significantly greater in the PEG-DLC-nitinol stent group (58.7±24.7%) than in the nitinol stent group (40.0±20.3%) (p = 0.01). Our findings indicate that DLC-coated nitinol stents might induce less neointimal hyperplasia than conventional nitinol stents following implantation in a canine iliac artery model; however, the DLC-coated nitinol stent surface when reformed with PEG induces more neointimal hyperplasia than either a conventional or DLC-coated nitinol stent.

  11. Cost-utility analysis of stenting versus endarterectomy in the International Carotid Stenting Study

    PubMed Central

    Morris, Stephen; Patel, Nishma V; Dobson, Joanna; Featherstone, Roland L; Richards, Toby; Luengo-Fernandez, Ramon; Rothwell, Peter M; Brown, Martin M

    2017-01-01

    Background The International Carotid Stenting Study (ICSS) was a multicentre randomised trial in which patients with symptomatic carotid artery stenosis were randomly allocated to treatment by carotid stenting or endarterectomy. Economic evidence comparing these treatments is limited and inconsistent. Aims We compared the cost-effectiveness of stenting versus endarterectomy using ICSS data. Methods We performed a cost-utility analysis estimating mean costs and quality-adjusted life years (QALYs) per patient for both treatments over a five-year time horizon based on resource use data and utility values collected in the trial. Costs of managing stroke events were estimated using individual patient data from a UK population-based study (Oxford Vascular Study). Results Mean costs per patient (95% CI) were US$10 477 ($9669 to $11 285) in the stenting group (N=853) and $9669 ($8835 to $10 504) in the endarterectomy group (N=857).There were no differences in mean QALYs per patient (3.247 (3.160 to 3.333) and 3.228 (3.150 to 3.306), respectively). There were no differences in adjusted costs between groups (mean incremental costs for stenting versus endarterectomy $736 (95% CI -$353 to $1826)) or adjusted outcomes (mean QALYs gained -0.010 (95% CI -0.117 to 0.097)). The incremental net monetary benefit for stenting versus endarterectomy was not significantly different from zero at the maximum willingness to pay for a QALY commonly used in the UK. Sensitivity analyses showed little uncertainty in these findings. Conclusions Economic considerations should not affect whether patients with symptomatic carotid stenosis undergo stenting or endarterectomy. PMID:26880056

  12. Biliary metal stents are superior to plastic stents for preoperative biliary decompression in pancreatic cancer.

    PubMed

    Decker, Christopher; Christein, John D; Phadnis, Milind A; Wilcox, C Mel; Varadarajulu, Shyam

    2011-07-01

    It is unclear whether plastic or metal stents are more suitable for preoperative biliary decompression in pancreatic cancer. The objective of this study was to compare the rate of endoscopic reinterventions in patients with pancreatic cancer undergoing plastic or self-expandable metal stent (SEMS) placements for preoperative biliary decompression. This was a retrospective study of all patients with obstructive jaundice secondary to pancreatic head cancer who underwent their index endoscopic retrograde cholangiopancreatography (ERCP) and all follow-up biliary stent placements at our center before undergoing pancreaticoduodenectomy. Plastic or SEMS were placed at ERCP for biliary decompression. The main outcome measure was to compare the rate of endoscopic reinterventions between the plastic and SEMS cohorts. 29 patients who underwent pancreaticoduodenectomy had preoperative biliary stent placement (18 plastic, 11 SEMS) at our center. Whereas none of the 11 patients who underwent SEMS placement had stent dysfunction, 7 of 18 (39%) patients with plastic stents required endoscopic reintervention before surgery (P=0.02). Reinterventions were due to cholangitis (n=1) or persistent elevation in serum bilirubin levels (n=6). Two patients with SEMS underwent EUS-guided fine-needle aspiration after ERCP, which yielded a positive diagnosis of cancer in all cases; SEMS did not impair visualization of the tumor mass at EUS. Pancreaticoduodenectomy was undertaken successfully in all 29 patients and the presence of a SEMS did not interfere with biliary anastomosis. On univariate logistic regression, only SEMS placement was associated with less need for endoscopic reintervention (P=0.02). SEMS are superior to plastic stents for preoperative biliary decompression in pancreatic cancer.

  13. Stent sizing by coronary computed tomographic angiography: comparison with conventional coronary angiography in an experienced setting.

    PubMed

    de Silva, Ramesh; Mussap, Christian J; Hecht, Harvey S; van Mieghem, Nicolas M; Matarazzo, Thomas J; Roubin, Gary S; Panagopoulos, Georgia

    2011-11-01

    The goal was to compare stent sizing by coronary computed tomographic angiography (CCTA) with that deployed in an experienced setting based upon conventional coronary angiography (CA). Stent sizing is currently performed by visual estimation, with infrequent guidance by intravascular ultrasound. CCTA permits quantitative determination of stent length (Stent L) and diameter (Stent D). Projected L (CTA-Stent L) and D (CTA-Stent D) were determined from CCTA obtained in 248 patients with 352 lesions undergoing percutaneous coronary intervention within 4 months of the CCTA, and were compared to the Stent-L and Stent-D of the actually deployed stents. The effects of lesion modification and calcified plaque were also evaluated. There were significant correlations between CTA-Stent L and Stent L (r = 0.656, P < 0.0001) and between CTA-Stent D and Stent D (r = 0.40, P < 0.001). Median predicted CTA-Stent L was slightly longer (20 mm vs. 18 mm, P < 0.0001) and predicted CTA-Stent D was slightly smaller (3.0 mm vs. 3.2 mm, P < 0.0001) than Stent-L and Stent-D, respectively. The differences were unchanged in stents with lesion modification by pre-dilation or intracoronary nitroglycerin. CTA Stent-L and CTA Stent-D increased significantly with increasing calcium (P < 0.0001 and P = 0.019, respectively). (1) There are significant correlations between CCTA and CA based stent sizing in an experienced setting. (2) CCTA projects slightly longer and slightly smaller diameter stents than those deployed during PCI irrespective of lesion modification; the small differences are unlikely to have clinical significance. (3) CCTA may offer a noninvasive alternative to intravascular ultrasound for stent planning. Copyright © 2011 Wiley-Liss, Inc.

  14. Flow diverter effect of LVIS stent on cerebral aneurysm hemodynamics: a comparison with Enterprise stents and the Pipeline device.

    PubMed

    Wang, Chao; Tian, Zhongbin; Liu, Jian; Jing, Linkai; Paliwal, Nikhil; Wang, Shengzhang; Zhang, Ying; Xiang, Jianping; Siddiqui, Adnan H; Meng, Hui; Yang, Xinjian

    2016-07-02

    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). 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. 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. 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.

  15. Mode of deployment of coronary Palmaz-Schatz stents after implantation with the stent delivery system: an intravascular ultrasound study.

    PubMed

    Kiemeneij, F; Laarman, G; Slagboom, T

    1995-04-01

    The stent delivery system (SDS) is a sheath-covered Palmaz-Schatz stent mounted on a 3.0, 3.5, or 4.0 mm compliant polyethylene balloon catheter; the balloon resists maximal inflation pressures of 5.7, 6.2, or 6.0 atm, respectively. It is postulated that these pressures are too low to obtain optimal stent deployment. Because optimal stent deployment is a prerequisite for optimal short- and long-term outcome, we performed an intravascular ultrasound study to the mode of stent deployment after delivery with the SDS and after high-pressure dilatations with low-compliant, oversized balloon catheters. In 23 patients an intravascular ultrasound study (30 MHz, 4.3F transducer) was performed to the geometry of 29 stents immediately after delivery with the SDS and after successive high-pressure inflations with low-compliant balloons. After delivery with the SDS (3.3 +/- 0.4 mm), stent diameter was 3.0 +/- 0.4 mm. After high-pressure dilatations (12.4 +/- 1.4 atm) with low-compliant balloons (3.9 +/- 0.5 mm), stent diameter increased to 3.4 +/- 0.4 mm (p < 0.001). Only 8 (28%) stents were completely and symmetrically expanded to the corresponding reference diameter with good apposition after delivery with the SDS. Diameter of incomplete deployed stents (n = 16) was 2.8 +/- 0.3 mm. After high-pressure dilatations with low-compliant balloons (3.9 +/- 0.5 mm), diameter increased to 3.4 +/- 0.4 mm (p < 0.001). Now 20 (69%) stents (p = 0.004) became completely and symmetrically expanded to a diameter corresponding to the reference diameter. In conclusion, most stents are suboptimally deployed after delivery with the stent delivery system.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Complications and management of forgotten long-term biliary stents

    PubMed Central

    Sohn, Se Hoon; Park, Jae Hyun; Kim, Kook Hyun; Kim, Tae Nyeun

    2017-01-01

    AIM To evaluate complications and management outcomes of retained long-term plastic biliary stents. METHODS Endoscopic plastic biliary stent placement was performed in 802 patients at Yeungnam University Hospital between January 2000 and December 2014. Follow-up loss with a subsequently forgotten stent for more than 12 mo occurred in 38 patients. We retrospectively examined the cause of biliary stent insertion, status of stents, complications associated with biliary stents and management outcomes of long-term plastic biliary stents. Continuous variables were analyzed using the t test. Observed frequencies in subsets of the study population were compared using Fisher’s exact test and χ2 tests. Statistical significance was defined as P < 0.05 (two-tailed). RESULTS Mean age of patients was 73.7 ± 12 years and male-to-female ratio was 2.2:1. Indications of plastic biliary stent insertion were bile duct stones (63.2%, 24/38) and benign bile duct stricture (52.6%, 20/38). Mean duration of retained plastic stent was 22.6 ± 12.2 mo, and in 10 cases (26.3%), stents were retained for more than 24 mo. Common bile duct (CBD) stones or sludge were found in most cases (92.1%, 35/38). The most common complication was acute cholangitis (94.7%, 36/38). Stent removal by endoscopic approach was successfully performed in 92.1% (35/38) of the cases. In 3 cases, an additional plastic stent was inserted alongside the previous stent due to failure of the stent removal. Endoscopic removal of bile duct stones was successful in 73.7% (28/38) of the cases. When patients were divided into two groups by duration of stent placement (12 to 24 mo vs over 24 mo), there were no differences in the development of cholangitis, presence of biliary stones, and success rate of endoscopic removal of stones and biliary stents. CONCLUSION The most common complication of retained long-term plastic biliary stents was acute cholangitis associated with CBD stones. Endoscopic management was successfully

  17. Complications and management of forgotten long-term biliary stents.

    PubMed

    Sohn, Se Hoon; Park, Jae Hyun; Kim, Kook Hyun; Kim, Tae Nyeun

    2017-01-28

    To evaluate complications and management outcomes of retained long-term plastic biliary stents. Endoscopic plastic biliary stent placement was performed in 802 patients at Yeungnam University Hospital between January 2000 and December 2014. Follow-up loss with a subsequently forgotten stent for more than 12 mo occurred in 38 patients. We retrospectively examined the cause of biliary stent insertion, status of stents, complications associated with biliary stents and management outcomes of long-term plastic biliary stents. Continuous variables were analyzed using the t test. Observed frequencies in subsets of the study population were compared using Fisher's exact test and χ(2) tests. Statistical significance was defined as P < 0.05 (two-tailed). Mean age of patients was 73.7 ± 12 years and male-to-female ratio was 2.2:1. Indications of plastic biliary stent insertion were bile duct stones (63.2%, 24/38) and benign bile duct stricture (52.6%, 20/38). Mean duration of retained plastic stent was 22.6 ± 12.2 mo, and in 10 cases (26.3%), stents were retained for more than 24 mo. Common bile duct (CBD) stones or sludge were found in most cases (92.1%, 35/38). The most common complication was acute cholangitis (94.7%, 36/38). Stent removal by endoscopic approach was successfully performed in 92.1% (35/38) of the cases. In 3 cases, an additional plastic stent was inserted alongside the previous stent due to failure of the stent removal. Endoscopic removal of bile duct stones was successful in 73.7% (28/38) of the cases. When patients were divided into two groups by duration of stent placement (12 to 24 mo vs over 24 mo), there were no differences in the development of cholangitis, presence of biliary stones, and success rate of endoscopic removal of stones and biliary stents. The most common complication of retained long-term plastic biliary stents was acute cholangitis associated with CBD stones. Endoscopic management was successfully performed in most cases.

  18. Late-acquired stent malapposition after sirolimus-eluting stent implantation following acute coronary syndrome: angiographic, IVUS, OCT and coronary angioscopic observation.

    PubMed

    Rathore, Sudhir; Terashima, Mitsuyasu; Suzuki, Takahiko

    2009-12-01

    Drug-eluting stents (DES) have been shown to significantly reduce the incidence of restenosis and target lesion revascularization in a wide variety of clinical situations. DES have also been shown to significantly reduce neointimal hyperplasia as compared to bare-metal stents. However, the antiproliferative properties of DES also delay vascular healing and have been associated with stent malapposition, hypersensitivity reactions and late stent thrombosis. Stent thrombosis could result in myocardial infarction or death. We describe here a case report of late stent malapposition following sirolimus-eluting stent implantation observed by angiography, intravascular ultrasound, optical coherence tomography and angioscopy.

  19. The Road to Bioabsorbable Stents: Reaching Clinical Reality?

    SciTech Connect

    Erne, Paul Schier, Matthias; Resink, Therese J.

    2006-02-15

    This article provides an overview of the evolution of revascularization devices since Gruentzig's initial introduction of balloon angioplasty in 1977. In-stent restenosis (ISR) is the major shortcoming of conventional (permanent-implant) stent therapy; even with the innovation and promising benefits of drug-eluting stents, management of ISR is very difficult. ISR is mainly caused by the interaction between the blood and the stent surface and a permanent mechanical irritation of the vascular tissue. Thus stenting technology has moved toward the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely biodegrade in the long term. Preclinical and first clinical experiences with bioabsorbable magnesium stents are discussed.

  20. Mathematical model of carotid artery for stent placement

    NASA Astrophysics Data System (ADS)

    Rahman, Tengku Husna Tengku Abdul; Din, Ummul Khair Salma; Ahmad, Rokiah @ Rozita

    2016-11-01

    The carotid artery stenting is one of the methods used to reduce the effect of artherosclerosis which caused by the thickening of the artery wall. In most of the studies, the measure of wall elasticity, shear stress and the blood pressure through the blood flow were considered. The aim of this study is to determine the position to place the stent inside the carotid artery. A mathematical model is reconstructed to determine the suitable location of the stent in the carotid artery. Throughout the study, differences in fluid flow between a normal carotid artery wall and stenosed carotid artery wall are investigated. Since the existence of the stenosis provides a resistance in the flow, it is important to identify the right position to place the stent. The stent will be placed in the position where stenosis exists to ease the blood to flow normally. Later after the stent placement, the blood flow normally through the blood vessel.

  1. The road to bioabsorbable stents: reaching clinical reality?

    PubMed

    Erne, Paul; Schier, Matthias; Resink, Therese J

    2006-01-01

    This article provides an overview of the evolution of revascularization devices since Grüntzig's initial introduction of balloon angioplasty in 1977. In-stent restenosis (ISR) is the major shortcoming of conventional (permanent-implant) stent therapy; even with the innovation and promising benefits of drug-eluting stents, management of ISR is very difficult. ISR is mainly caused by the interaction between the blood and the stent surface and a permanent mechanical irritation of the vascular tissue. Thus stenting technology has moved toward the development of temporary implants composed of biocompatible materials which mechanically support the vessel during the period of high risk for recoil and then completely biodegrade in the long term. Preclinical and first clinical experiences with bioabsorbable magnesium stents are discussed.

  2. Post-biliary sphincterotomy bleeding despite covered metallic stent deployment

    PubMed Central

    Donatelli, Gianfranco; Cereatti, Fabrizio; Dumont, Jean-Loup; Dhumane, Parag; Tuszynski, Thierry; Vergeau, Bertrand Marie; Meduri, Bruno

    2016-01-01

    Objectives: Several endoscopic techniques have been proposed for the management of post-sphincterotomy bleeding. Lately, self-expandable metal stents deployment has gained popularity especially as a rescue therapy when other endoscopic techniques fail. Methods-results: We report the case report of a massive post-sphincterotomy bleeding in a patient with a self-expandable metal stent in the biliary tree. Despite the presence of a correctly positioned self-expandable metal stent, a new endoscopic session was required to control the bleeding. Conclusions: Self-expandable metal stent may be useful to manage post-endoscopic sphincterotomy bleeding. However, up to now there is no specifically designed self-expandable metal stent for such complication. Large new designed self-expandable metal stent may be a useful tool for biliary endoscopist. PMID:27489716

  3. On high-cycle fatigue of 316L stents.

    PubMed

    Barrera, Olga; Makradi, Ahmed; Abbadi, Mohammed; Azaouzi, Mohamed; Belouettar, Salim

    2014-01-01

    This paper deals with fatigue life prediction of 316L stainless steel cardiac stents. Stents are biomedical devices used to reopen narrowed vessels. Fatigue life is dominated by the cyclic loading due to the systolic and diastolic pressure and the design against premature mechanical failure is of extreme importance. Here, a life assessment approach based on the Dang Van high cycle fatigue criterion and on finite element analysis is applied to explore the fatigue reliability of 316L stents subjected to multiaxial fatigue loading. A finite element analysis of the stent vessel subjected to cyclic pressure is performed to carry out fluctuating stresses and strain at some critical elements of the stent where cracks or complete fracture may occur. The obtained results show that the loading path of the analysed stent subjected to a pulsatile load pressure is located in the safe region concerning infinite lifetime.

  4. Subintimal Double-Barrel Restenting of an Occluded Primary Stented Superficial Femoral Artery

    SciTech Connect

    Duterloo, Dirk Lohle, Paul N.M.; Lampmann, Leo E.H.

    2007-06-15

    In-stent re-stenosis is a frequent complication of endovascular stents, especially in the superficial femoral artery (SFA). Endovascular re-intervention of in- or peri-stent occlusive disease consists of recanilization through the occluded stent. In our case report, we describe the endovascular treatment of a previously placed stent in the SFA. We unintentionally passed the affected stent subintimally, in a double barrel fashion next to the first stent. The procedure was without any complications and with a successful angiographic result. At one year follow-up the patient still has no complaints and the stent is still patent.

  5. Drug-eluting versus bare-metal coronary stents: where are we now?

    PubMed

    Amoroso, Nicholas S; Bangalore, Sripal

    2012-11-01

    Drug-eluting stents have dramatically reduced the risk of restenosis, but concerns of an increased risk of stent thrombosis have provided uncertainty about their use. Recent studies have continued to show improved procedural and clinical outcomes with drug-eluting stents both in the setting of acute coronary syndromes and stable coronary artery disease. Newer generation drug-eluting stents (especially everolimus-eluting stents) have been shown to be not only efficacious but also safe with reduced risk of stent thrombosis when compared with bare-metal stents, potentially changing the benchmark for stent safety from bare-metal stents to everolimus-eluting stents. While much progress is being made in the development of bioabsorbable polymer stents, nonpolymer stents and bioabsorbable stent technology, it remains to be seen whether these stents will have superior safety and efficacy outcomes compared with the already much improved rates of revascularization and stent thrombosis seen with newer generation stents (everolimus-eluting stents and resolute zotarolimus-eluting stents).

  6. Fractures of self-expanding metallic stents in periampullary malignant biliary obstruction.

    PubMed

    Rasmussen, I C; Dahlstrand, U; Sandblom, G; Eriksson, L G; Nyman, R

    2009-09-01

    Self-expanding metallic stents are widely used for relieving biliary duct obstruction in patients with unresectable periampullary malignancies. However, only a few studies have assessed the occurrence of fractures in these stents. To determine the prevalence and significance of stent fracture after placement of self-expanding metallic stents for periampullary malignant biliary obstruction. Over a 5-year period, 48 patients underwent placement of self-expanding metallic stents for periampullary malignant biliary obstructions. Stents were introduced 2-6 weeks after a percutaneous transhepatic biliary decompression. The medical records and relevant images were reviewed for stent patency, stent fracture, type of stent, and stent-related complications. Stent fracture was detected in four of the 48 patients (8%): in one patient at 1 month and in three patients between 10 and 21 months after stenting. All four fractures involved one type of nitinol stent used in 38 patients. In one of the patients, fracture was complicated by life-threatening gastrointestinal bleeding. The mean survival time for all patients was 251 days (standard deviation [SD]+/-275 days) and the mean overall patency time for all stents was 187 days (SD+/-205 days). Stent fracture occurs after placement of self-expanding nitinol stents for periampullary malignant biliary obstruction. The low reported incidence of this complication may be due to a lack of awareness of and difficulty in detecting stent fracture. Fracture should be considered as a possible contributing factor in recurrent biliary obstruction after self-expanding metallic stent insertion.

  7. Subintimal Double-Barrel Restenting of an Occluded Primary Stented Superficial Femoral Artery

    PubMed Central

    Lohle, Paul N.M.; Lampmann, Leo E.H.

    2007-01-01

    In-stent re-stenosis is a frequent complication of endovascular stents, especially in the superficial femoral artery (SFA). Endovascular re-intervention of in- or peri-stent occlusive disease consists of recanilization through the occluded stent. In our case report, we describe the endovascular treatment of a previously placed stent in the SFA. We unintentionally passed the affected stent subintimally, in a double barrel fashion next to the first stent. The procedure was without any complications and with a successfull angiographic result. At one year follow-up the patient still has no complaints and the stent is still patent. PMID:17410397

  8. Angiographic and clinical outcomes after implantation of drug eluting stents in bifurcation lesions with crush or kissing stent technique.

    PubMed

    Cheema, Asim N; Jolly, Sanjit S; Burstein, Jason M; Sharieff, Waseem; Mohammad, Atif; Yeoh, Eunice; Mancini, G B John; Cantor, Warren J; Kutryk, Michael J B; Strauss, Bradley H; Chisholm, Robert J

    2013-04-01

    Long-term outcome after bifurcation stenting with drug-eluting stents (DES) for obstructive coronary artery disease is poorly understood. In this study, we report 6-9-month angiographic follow-up and long-term clinical outcomes after implantation of drug-eluting stents by crush and kissing stent technique for coronary bifurcation lesions. Consecutive patients undergoing bifurcation stenting with DES by crush or kissing stent technique were enrolled in a prospective registry. Angiographic follow-up was obtained at 6-9 months and clinical follow-up completed for a median of 38 months. A total of 86 patients participated in the study. Bifurcation stenting by crush technique was performed in 73 (85%) and by kissing stent in 13 (15%) patients. Stenting of left main bifurcation was applied in 24 (28%) patients. Angiographic follow-up was completed in 75 (87%) patients and showed restenosis in the main for 8 (11%) and side branch for 20 (27%) patients. Clinical follow-up was available for a median duration of 38 months. During follow-up, 2 (2%) patients died, 4 (5%) experienced myocardial infarction (MI), and 11 (13%) underwent target vessel revascularization (TVR) with an overall major adverse cardiac event (MACE) rate of 16%. In left main cohort, angiographic restenosis occurred in 9 (37%) patients, and 3 (12%) patients required TVR. There were no deaths or stent thrombosis. A comparison of crush and kissing stent technique showed significantly higher angiographic restenosis with crush (26% vs 13% in kissing stent patients, P = 0.046) and 95% of restenosis in crush group involved ostium of the side branch. There was no difference in clinical outcomes between the crush and kissing stent groups. Final kissing balloon dilatation (FKB) was successful in 65 (89%) patients in the crush group and associated with a significant reduction in MACE (8% in FKB successful vs 37% in FKB unsuccessful, P = 0.04) during follow-up. Bifurcation stenting with crush or kissing stent

  9. Successful Coronary Stent Retrieval From a Pedal Artery

    SciTech Connect

    Mariano, Enrica Versaci, Francesco; Gandini, Roberto; Simonetti, Giovanni; Di Vito, Livio; Romeo, Francesco

    2008-05-15

    The purpose of this article is to report complications from a coronary drug-eluting stent lost in the peripheral circulation. We report the case of successful retrieval of a sirolimus coronary stent from a pedal artery in a young patient who underwent coronary angiography for previous anterior myocardial infarction. Recognition of stent embolization requires adequate removal of the device to avoid unwelcome clinical sequelae.

  10. Modified technique of stent fenestration of the atrial septum

    PubMed Central

    Stümper, O; Gewillig, M; Vettukattil, J; Budts, W; Chessa, M; Chaudhari, M; Wright, J G C

    2003-01-01

    Objectives: To develop a modified technique for stenting the atrial septum in the treatment of patients with a failing Fontan operation or pulmonary hypertension. Setting: Two tertiary referral centres. Study design: Prospective collaborative clinical study. Patients and methods: A stent was mounted on a standard valvoplasty balloon catheter which was constricted to a predefined diameter by a loop created from a temporary pacing wire. Full balloon inflation created a diabolo shaped stent configuration. The technique was employed in 12 consecutive patients to relieve symptoms of a failing Fontan circulation (n = 6) or severe pulmonary hypertension (n = 6). Results: Ex vivo studies confirmed that a diabolo shaped stent configuration could be achieved using the above technique. Transcatheter stent implantation was successful in all 12 patients. All six Fontan patients showed significant clinical improvement. Right atrial pressure decreased from (mean (SD)) 16.8 (2.5) to 13.7 (1.9) mm Hg (p < 0.05), and arterial oxygen saturation from 92.8 (1.8)% to 82.7 (3.8)% (p < 0.01). Six patients underwent successful stent fenestration for treatment of pulmonary hypertension. All stents were patent and stable at the most recent follow up (mean 1.75 (1.05) years). No early or late stent related complications were encountered. Conclusions: This new technique allows placement of a diabolo shaped stent with a predefined diameter across the atrial septum. The diabolo shape increases stent stability, facilitates recrossing of the stent during future catheter interventions, and ensures medium term stent patency. PMID:12975427

  11. The nature and pattern of coronary stent recalls.

    PubMed

    Kumar, Sanjay; Innasimuthu, Antony L; Marmur, Jonathan D

    2014-09-01

    Each year, over 1 million percutaneous coronary interventions (PCIs) are performed in the United States. Coronary stents have been shown to reduce restenosis or abrupt vessel closure and therefore have improved the success of PCI. Rarely, manufacturers recall stents due to unanticipated problems. We sought to study the extent and pattern of stent recall. To determine the number and rate of stent recall and safety alerts, to identify trends in the rates, and to identify the nature of stent recalls. The Food and Drug Administration (FDA; http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfRES/res.cfm) and Healthcare Recall Management websites (RASMAS; https://alerts.rasmas.noblis.org/rasmas/c/selectViewAlertList.do) were searched. The search terms for recall were, "coronary stent" or "stent." Dates were searched between November 2002 and June 2013. There were 17 coronary stent recalls involving almost 500,000 units; 12 recalls (71%) were before 2006 and 5 recalls (29%) were after. Thirteen recalls (76%) consisted of class II recalls (moderate hazard); the remaining 4 were equally split between class I (severe hazard) and class III (mild hazard; 12% each). The common reasons for recall were concerns with sterility (29%) followed by wrong labeling/packaging (23%) and impaired delivery of stent (18%). In terms of units involved with recalls, 98% (472,189/481,131) were related to wrong labeling/ packaging or misbranding, while 0.1% (542/481,131) were related to potential for broken struts or crack in inflation port hub or sterility. However, approximately 2% of units were related to the potentially lethal problem of impaired balloon inflation. Recalls involved multiple manufacturers with various stent types. The overall incidence of coronary stent recall is low and has declined over the years. The majority of stent recalls are of moderate hazard. However, due to the possibility of serious injury, clinicians should be aware of recalls.

  12. Tips and tricks for stenting of bifurcation coronary lesions.

    PubMed

    Kwan, Tak W; Vales, Lori; Liou, Michael; Kanei, Yumiko; Chen, Shao-Liang

    2010-09-01

    Although the provisional stenting technique to treat coronary bifurcation lesions is the preferred method, many bifurcation lesions still require a two-stent technique to optimize the result and clinical outcome. This manuscript summarizes the tips and tricks of bifurcation stenting with cases illustrations. As interventionists are encountering more complex and difficult cases, one may find the tips and tricks in this manuscript helpful in daily practice.

  13. Experimental Study of Blood Laminar Flow Through a Stented Artery

    DTIC Science & Technology

    2001-10-25

    stenosis in coronary arteries. Since the 80’s, there is an alternative to the usual balloon angioplasty . Indeed, the use of tiny metallic scaffolds (named...following one: the coronary stent is placed over the angioplasty balloon and moved to the site of lesion. The stent expands with the balloon and remains...values. The coronary angioplasty is responsible of wall shear stress modification, mainly between the stent struts, at the inlet and the outlet of

  14. Percutaneous transradial artery approach for coronary stent implantation.

    PubMed

    Kiemeneij, F; Laarman, G J

    1993-10-01

    A new approach for implantation of Palmaz Schatz coronary stents is reported. We describe the technique and rationale of coronary stenting with miniaturized angioplasty equipment via the radial artery. This technique is illustrated in three patients. One patient underwent Palmaz Schatz stent implantation for a saphenous vene coronary bypass graft stenosis, the second patient for a restenosis in the anterior descending coronary artery after atherectomy, and the third patient for a second restenosis after balloon angioplasty in the circumflex coronary artery.

  15. Direct coronary stenting by transradial approach: rationale and technical issues.

    PubMed

    Burzotta, Francesco; Hamon, Martial; Trani, Carlo; Kiemeneij, Ferdinand

    2004-10-01

    Direct stent implantation using radial approach represents to date the less invasive, less traumatic strategy to perform a percutaneous coronary intervention, rendering its adoption an attraction for many interventional cardiologists. A growing series of reports suggests the feasibility of transradial direct stenting in a variety of clinical situations. Here we discuss the main advantages of the adoption of this technique. Moreover, a detailed analysis of the technical issues specifically related with each phase of transradial direct stenting procedures is reported.

  16. Primary Stent Placement for Recanalization of Iliac Artery Occlusions: Using a Self-Expanding Spiral Stent

    SciTech Connect

    Kim, Jae-Kyu; Kim, Yun-Hyeon; Chung, Sang-Yeung; Kang, Heoung-Keun

    1999-07-15

    Purpose: To report the clinical results for recanalizations of an occluded iliac artery by a self-expanding spiral stent. Methods: We attempted to recanalize 36 iliac artery occlusions in 34 patients [33 men, 1 woman, aged 51-75 years (average 61.6 years)]. The average lesion length was 6.92 cm (range 1-14 cm). The patients' chief complaints were intermittent claudication and resting pain. Fontaine classification was assigned before and after the procedure. Technical and clinical success were also analyzed. Results: Forty-five stents were successfully deployed in 34 patients. All 36 lesions (13 in the external iliac artery, 12 in the common iliac artery, and 11 in both) were patently recanalized on angiography. The follow-up period ranged from 6 months to 36 months (mean 11.9 months). Fourteen stents (39%) with incomplete expansion were dilated with a balloon catheter. Good technical (100%) and clinical (94%) results were obtained. The only complication was one hematoma at the puncture site. Reocclusions were noted in two lesions (5%) at 1 week and 15 months, respectively. Conclusion: A self-expanding spiral stent is a safe and effective device for recanalization of an iliac artery occlusion as the primary stent without any previous intervention.

  17. Evaluation of Polyurethane Nasolacrimal Duct Stents: In Vivo Studies in New Zealand Rabbits

    SciTech Connect

    Wilhelm, K.E. Grabolle, B.; Urbach, H.; Tolba, R.; Schild, H.; Paulsen, F.

    2006-10-15

    The purpose of this study was to evaluate the radiographic and biological effects of different polyurethane nasolacrimal duct stents in an animal model. Fifteen polyurethane nasolacrimal duct stents (n = 5 mushroom-type stents, n = 5 newly designed S-shaped TearLeader stents without hydrophilic coating, and n = 5 S-shaped TearLeader stents with hydrophilic coating) were implanted in the nasolacrimal ducts of eight unaffected New Zealand rabbits. One nasolacrimal system served as control. Clinical and radiographic follow-up was performed at 1-, 2-, and 4-week intervals, then after a 3-month interval, after which the animals were euthanized. All stents were implanted without major periprocedural complications. The stents proved to be patent by the end of the procedure. During follow-up, all mushroom-type stents were occluded at 4 weeks. None of these stents opened to forced irrigation. Clinically, all rabbits demonstrated severe dacryocystitis. Three out of five TearLeader stents without hydrophilic coating were blocked at 4 weeks; one out of five was open to irrigation. Best results were observed in the stent group with hydrophilic coating. Follow-up dacryocystography demonstrated patent stents in nasolacrimal ducts of all animals after 4 weeks. In only one of five cases, the coated stent became partially occluded after 2 months. These animals were free of clinical symptoms. After 3 months, at least three out of five stents still opened to forced irrigation and only one stent was completely blocked. Dislocation of the stents was not observed. Refinement of the stent surface and stent design improves the results of nasolacrimal duct stenting in this animal model. Implantation of hydrophilic-coated S-shaped stents is highly superior to conventional mushroom-type stents and noncoated stent types. Hydrophilic coating seems to prevent foreign-body reactions, resulting in maximized stent patency.

  18. [Endarterectomy more favourable than stenting in symptomatic significant carotid stenosis: higher risk of ischaemic stroke or death following stenting].

    PubMed

    Meerwaldt, Robbert; Beuk, Roland J; Huisman, Ad B; Manschot, Sanne M; Zeebregts, Clark J; Geelkerken, Robert H

    2011-01-01

    Carotid endarterectomy (CEA) has proven its value in the treatment of patients with recent significant carotid artery stenosis. Percutaneous transluminal angioplasty with carotid artery stenting ('stenting' in short) is an alternative to CEA. The results of stenting and CEA in patients with symptomatic significant carotid artery stenosis were evaluated in 9 prospective randomized controlled trials and 11 meta-analyses. Almost all of these trials failed to show superiority of stenting to CEA. According to the 4 largest and most recent studies in this field the risk of a stroke or death within 30 days after the intervention is considerably higher following stenting than following CEA. In the long run the results of stenting and CEA seem to be comparable. CEA remains the gold standard in treatment of significant carotid artery stenosis, in particular in patients older than 70.

  19. Lasers in the management of calcified urinary tract stents

    NASA Astrophysics Data System (ADS)

    Nseyo, Unyime O.; Tunuguntla, Hari S. G. R.; Crone, Michael

    2003-06-01

    Indwelling double J ureteral stents are used for internal urinary diversion for ureteral obstruction and post-surgical drainage of the upper urinary tract. Stent calcification is a serious complication especially in those with forgotten stents. In a retrospective review of 16 patients (10 male and 6 female) we found holmium laser to be highly effective in the management of calcified stents. Encrustations/calcifications were noted on the distal end of the sent in 6 patiens (37.5%), middle and distal portions in 2 patients (12.5%), along the entire length of the stent in 3 patients (18.75%), lower portion of the stent in 4 patients (25%) and at the upper and lower ends of the stent in one patient (6.25%). Cystolitholapaxy, retrograde ureteroscopy (URS) with holmium: YAG (yttrium-aluminum-garnet) laser intracorporeal lithotripsy, percutaneous nephrostolithotomy (PNL) and antegrade URS with holmium: YAG laser intracorporeal lithotripsy were effectively performed without intraoperative complications. Lithotripsy became necessary before stent removal in 11 patients (68.75%). Holmium laser lithotripsy was useful in managing 7 patients (43.75%), and shockwave lithotripsy (SWL) in 6 patients (37.5%). In two patients (12.5%) both holmium and SWL were used before the stent can be removed.

  20. Hemodynamics and transient flow reversal in real deployed stents

    NASA Astrophysics Data System (ADS)

    Metcalfe, Ralph; Ionescu, Mircea

    2011-11-01

    Restenosis rates caused by neointimal hyperplasia are relatively high (~ 30 %) after stent implantation in stenosed arteries. The flow around stent struts under steady and unsteady conditions using computational hemodynamics (CHD) was studied to identify contributing factors to the formation of low and oscillating wall shear stress regions that have been shown to promote endothelial dysfunction and atherosclerotic plaque formation in arteries. Datasets of the Neuroform, BxVelocity, and Taxus stents deployed in straight polymer tubes were obtained from high resolution micro computed tomography. Finite volume CHD simulations of steady and unsteady flow with and without flow reversal were performed. Stagnation zones were noticed adjacent to the strut junctions as the flow enters and exits the stent cells. The stagnation zones were larger in the case of the stents with larger strut diameter (BxVelocity, Taxus), wider strut junctions and larger angles between the struts. Unsteady flow simulations showed enhanced flow reversal with thicker struts and large regions of recirculation flow developing inside the stent at Reynolds numbers higher than 200. It was shown that alterations in blood flow due to real stent deployment (strut prolapse, junction misalignment) cannot be captured with computer generated stent models, that stent specific geometry, and time dependent flow effects can locally alter the wall shear stress and stagnation zones.

  1. The MGuard coronary stent: safety, efficacy, and clinical utility

    PubMed Central

    Gracida, Montserrat; Romaguera, Rafael; Jacobi, Francisco; Gómez-Hospital, Joan A; Cequier, Angel

    2015-01-01

    Atheromatous and thrombotic embolization during percutaneous coronary revascularization is a feared complication that may cause impaired myocardial reperfusion even with a patent epicardial vessel. The MGuard stent is a cobalt chromium bare metal stent with a porous net attached to its outer surface that has been designed to prevent thrombus fragmentation and distal embolization during stent implantation. This review summarizes the available evidence supporting the use of the MGuard stent in different scenarios such as lesions with high thrombus burden, saphenous vein graft interventions, coronary perforations, or carotid lesions. PMID:26425097

  2. A review on biodegradable materials for cardiovascular stent application

    NASA Astrophysics Data System (ADS)

    Hou, Li-Da; Li, Zhen; Pan, Yu; Sabir, MuhammadIqbal; Zheng, Yu-Feng; Li, Li

    2016-09-01

    A stent is a medical device designed to serve as a temporary or permanent internal scaffold to maintain or increase the lumen of a body conduit. The researchers and engineers diverted to investigate biodegradable materials due to the limitation of metallic materials in stent application such as stent restenosis which requires prolonged anti platelet therapy, often result in smaller lumen after implantation and obstruct re-stenting treatments. Biomedical implants with temporary function for the vascular intervention are extensively studied in recent years. The rationale for biodegradable stent is to provide the support for the vessel in predicted period of time and then degrading into biocompatible constituent. The degradation of stent makes the re-stenting possible after several months and also ameliorates the vessel wall quality. The present article focuses on the biodegradable materials for the cardiovascular stent. The objective of this review is to describe the possible biodegradable materials for stent and their properties such as design criteria, degradation behavior, drawbacks and advantages with their recent clinical and preclinical trials.

  3. Pulmonary Arterial Stent Implantation in an Adult with Williams Syndrome

    SciTech Connect

    Reesink, Herre J.; Henneman, Onno D. F.; Delden, Otto M. van; Biervliet, Jules D.; Kloek, Jaap J.; Reekers, Jim A.; Bresser, Paul

    2007-07-15

    We report a 38-year-old patient who presented with pulmonary hypertension and right ventricular dysfunction due to pulmonary artery stenoses as a manifestation of Williams syndrome, mimicking chronic thromboembolic pulmonary hypertension. The patient was treated with balloon angioplasty and stent implantation. Short-term follow-up showed a good clinical result with excellent patency of the stents but early restenosis of the segments in which only balloon angioplasty was performed. These stenoses were subsequently also treated successfully by stent implantation. Stent patency was observed 3 years after the first procedure.

  4. Radiological Management of Superior Vena Caval Stent Migration and Infection

    SciTech Connect

    Srinathan, Sadeesh McCafferty, Ian; Wilson, Ian

    2005-01-15

    We report a case of venous obstruction secondary to Hodgkin's lymphoma. Multiple Wallstents were inserted into the superior vena cava to relieve obstructive symptoms secondary to tumor. This procedure was complicated by stent migration into the right ventricle and a presumed stent infection. We describe the percutaneous management of these complications and discuss the issues surrounding the use of stents in this setting. We conclude that these complications can be managed percutaneously. However, the technical details of stent placement are essential in minimizing complications of this type.

  5. Stent edge dissection: depth of injury and adverse outcome.

    PubMed

    Goldstein, James A

    2015-08-01

    Deep stent edge dissection by OCT predicts adverse outcome. STEMI culprit lesions are most susceptible to edge dissection. Procedural performance influences edge dissection. © 2015 Wiley Periodicals, Inc.

  6. Patient-specific modeling of intracranial aneurysmal stenting

    NASA Astrophysics Data System (ADS)

    Appanaboyina, Sunil; Mut, Fernando; Löhner, Rainald; Putman, Christopher M.; Cebral, Juan R.

    2007-03-01

    Simulating blood flow around stents in intracranial aneurysms is important for designing better stents and to personalize and optimize endovascular stenting procedures in the treatment of these aneurysms. However, the main difficulty lies in the generation of acceptable computational grids inside the blood vessels and around the stents. In this paper, a hybrid method that combines body-fitted grid for the vessel walls and adaptive embedded grids for the stent is presented. Also an algorithm to map a particular stent to the parent vessel is described. These approaches tremendously simplify the simulation of blood flow past these devices. The methodology is evaluated with an idealized stented aneurysm under steady flow conditions and demonstrated in various patient-specific cases under physiologic pulsatile flow conditions. These examples show that the methodology can be used with ease in modeling any patient-specific anatomy and using different stent designs. This paves the way for using these techniques during the planning phase of endovascular stenting interventions, particularly for aneurysms that are difficult to treat with coils or by surgical clipping.

  7. Pulmonary arterial stent implantation in an adult with Williams syndrome.

    PubMed

    Reesink, Herre J; Henneman, Onno D F; van Delden, Otto M; Biervliet, Jules D; Kloek, Jaap J; Reekers, Jim A; Bresser, Paul

    2007-01-01

    We report a 38-year-old patient who presented with pulmonary hypertension and right ventricular dysfunction due to pulmonary artery stenoses as a manifestation of Williams syndrome, mimicking chronic thromboembolic pulmonary hypertension. The patient was treated with balloon angioplasty and stent implantation. Short-term follow-up showed a good clinical result with excellent patency of the stents but early restenosis of the segments in which only balloon angioplasty was performed. These stenoses were subsequently also treated successfully by stent implantation. Stent patency was observed 3 years after the first procedure.

  8. Complications during renal artery stent placement for atherosclerotic ostial stenosis

    SciTech Connect

    Beek, Frederik J. A.; Kaatee, Robert; Beutler, Jaap J.; Ven, Peter J. van der; Mali, Willem P. T. M.

    1997-05-15

    Purpose. To describe short-term complications during stent placement for atherosclerotic renal artery ostial stenosis. Methods. Sixty-one arteries in 50 patients were treated with Palmaz stents. Nineteen patients had a single functioning kidney, 23 had a bilateral stenosis, which was stented bilaterally in 11, and 8 had a unilateral stenosis. The complications were grouped as those related to the catheterization procedure, those related to stent placement, and those possibly related to either category. The complications were divided into those with severe clinical significance (SCS), those with minor clinical significance (MCS), and radiological-technical complications (RTC). The stent placement procedures were ordered chronologically according to examination date and the complications were tabulated per group of 10 patients. Results. Five (10%) SCS, 5 (10%) MCS, and 8 (16%) RTC occurred in 50 patients. The catheterization procedure led to 2 SCS, 3 MCS, and 1 RTC. Stent placement gave rise to 7 RTC. Three SCS and 2 MCS could have been related to either catheterization or stent placement. More SCS occurred in the first group of 10 patients than in the following groups. Conclusion. Renal artery stent placement for atherosclerotic ostial stenosis has a considerable complication rate and a learning curve is present. The complications related to the actual stent placement were without clinical consequences.

  9. Prophylactic stenting for esophageal stricture prevention after endoscopic submucosal dissection

    PubMed Central

    Shi, Ke-Da; Ji, Feng

    2017-01-01

    Endoscopic submucosal dissection (ESD) of superficial esophageal cancer has been increasingly used as an alternative to surgery because it is minimally invasive and has a high rate of en bloc resection. However, a high rate of esophageal stricture is observed after ESD for large lesions, which can dramatically decrease the patient’s quality of life. Stricture prevention is necessary to allow for endoscopic therapy to expand. We, herein, review the most recent evidence and discuss the role of the metallic self-expandable stent and the biodegradable stent in esophageal stricture prevention. Limited studies suggested that prophylactic stenting could reduce the stricture rate without increasing the number of complications. In addition, the number of bougie dilation procedures was significantly lower with stent placement. Esophageal stenting is a promising option for post-ESD stricture prevention. However, current evidence is too preliminary to formulate practice standards. Future studies are needed to further validate the efficacy and safety of prophylactic stenting and determine the best strategy for stricture prevention. Stent migration is the most common complication. A new stent that has advantages of a low migration rate and minimal tissue reaction will need to be developed. Therefore, randomized controlled trials with long-term follow-up periods are required before prophylactic stenting could be considered a valid option to prevent post-ESD stricture. PMID:28246466

  10. Angioscopic Evaluation of Neointimal Coverage of Coronary Stents.

    PubMed

    Uchida, Yasumi; Uchida, Yasuto

    2010-10-01

    Drug-eluting stents (DES) reduce coronary restenosis significantly; however, late stent thrombosis (LST) occurs, which requires long-term antiplatelet therapy. Angioscopic grading of neointimal coverage of coronary stent struts was established, and it was revealed that neointimal formation is incomplete and prevalence of LST is higher in DES when compared to bare-metal stents. It was also observed that the neointima is thicker and LST is less frequent in paclitaxel-eluting and zotarolimus-eluting stents than in sirolimus-eluting stents. Many new stents were devised and they are now under experimental or clinical investigations to overcome the shortcomings of the stents that have been employed clinically. Endothelial cells are highly anti-thrombotic. Neo-endothelial cell damage is considered to be caused by friction between the cells and stent struts due to the thin neointima between them which might act as a cushion. Therefore, development of a DES that causes an appropriate thickness (around 100 μm) of the neointima is a potential option with which to prevent neo-endothelial cell damage and consequent LST while preventing restenosis.

  11. Role of stenting in gastrointestinal benign and malignant diseases

    PubMed Central

    Mangiavillano, Benedetto; Pagano, Nico; Arena, Monica; Miraglia, Stefania; Consolo, Pierluigi; Iabichino, Giuseppe; Virgilio, Clara; Luigiano, Carmelo

    2015-01-01

    Advances in stents design have led to a substantial increase in the use of stents for a variety of digestive diseases. Initially developed as a non-surgical treatment for palliation of esophageal cancer, the stents now have an emerging role in the management of malignant and benign conditions as well as in all segments of the gastrointestinal tract. In this review, relevant literature search and expert opinions have been used to evaluate the key-role of stenting in gastrointestinal benign and malignant diseases. PMID:25992186

  12. [Magnetic resonance compatibility research for coronary mental stents].

    PubMed

    Wang, Ying; Liu, Li; Wang, Shuo; Shang, Ruyao; Wang, Chunren

    2015-01-01

    The objective of this article is to research magnetic resonance compatibility for coronary mental stents, and to evaluate the magnetic resonance compatibility based on laboratory testing results. Coronary stents magnetic resonance compatibility test includes magnetically induced displacement force test, magnetically induced torque test, radio frequency induced heating and evaluation of MR image. By magnetic displacement force and torque values, temperature, and image distortion values to determine metal coronary stent demagnetization effect. The methods can be applied to test magnetic resonance compatibility for coronary mental stents and evaluate its demagnetization effect.

  13. [Finite Element Analysis of Intravascular Stent Based on ANSYS Software].

    PubMed

    Shi, Gengqiang; Song, Xiaobing

    2015-10-01

    This paper adopted UG8.0 to bulid the stent and blood vessel models. The models were then imported into the finite element analysis software ANSYS. The simulation results of ANSYS software showed that after endothelial stent implantation, the velocity of the blood was slow and the fluctuation of velocity was small, which meant the flow was relatively stable. When blood flowed through the endothelial stent, the pressure gradually became smaller, and the range of the pressure was not wide. The endothelial shear stress basically unchanged. In general, it can be concluded that the endothelial stents have little impact on the flow of blood and can fully realize its function.

  14. [Jejunal perforation by a plastic biliary stent after injury].

    PubMed

    Krska, Z; Brůha, R; Sváb, J; Demes, R; Votrubová, J; Petrtýl, J; Horejs, J

    2004-02-01

    The authors present case of patient with biliary stent dislocation after chest injury and fracture of VIII. rib. Polymorbid patient with cirrhosis, chronic pancreatitis, portal hypertension (Child Plugh B) and biliary stent insertion came with acute abdominal pain and inflammatory signs. Progressive signs of acute abdomen have led to laparotomy. Perforation of duodeno-jejunal-loop due to dislocated biliary stent, small loop adhesions and thickened intestine wall were found. Postsurgical period was complicated with obstructive ileus, cholecystitis and cholangiolitis and the second biliary stent was inserted. Present-day status of the patient is satisfactory.

  15. Percutaneous Endoluminal Bypass of Iliac Aneurysms with a Covered Stent

    SciTech Connect

    Ruebben, Alexander; Tettoni, Serena; Muratore, Pierluigi; Rossato, Dennis; Savio, Daniele; Rabbia, Claudio

    1998-07-15

    To evaluate the feasibility of percutaneous treatment of iliac aneurysms, a covered stent was inserted in nine men suffering from common iliac artery aneurysms (six cases), external iliac aneurysms (one case), or pseudoaneurysms (two cases). Placement of the stent was successful in all patients. In one patient, an endoprosthesis thrombosed after 15 days, but was successfully treated by thrombolysis and additional stent placement. At the follow-up examinations (mean period 22 months) all stent-grafts had remained patent. No late leakage or stenosis was observed.

  16. Isolation of high-quality RNA from stented blood vessels.

    PubMed

    Van Dyck, Christophe J; Timmermans, Jean-Pierre; Fransen, Erik; Vrints, Christiaan J; Hoymans, Vicky Y

    2013-09-01

    Stents have become a standard of care for the treatment of coronary artery disease. A series of cellular and molecular processes contribute to the vascular response following stent placement. For the purpose of local gene expression studies, metallic stent struts are usually removed from the vessel wall with forceps under a dissection microscope prior to RNA extraction. Main drawbacks of the manual dissection are that it may cause additional tissue damage and compromise the quality of RNA through prolonged tissue handling. In this technical note, we report the recovery of high-quality RNA from atherosclerotic vessels with stent struts left in situ. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Serial Versus Direct Dilation of Small Diameter Stents Results in a More Predictable and Complete Intentional Transcatheter Stent Fracture: A PICES Bench Testing Study.

    PubMed

    Crystal, Matthew A; Morgan, Gareth J; Danon, Saar; Gray, Robert G; Gruenstein, Daniel H; Gordon, Brent M; Goldstein, Bryan H

    2017-10-04

    Balloon-expandable stents, implanted in infants and children with congenital heart disease (CHD), often require redilation to match somatic growth. Small diameter stents may eventually require longitudinal surgical transection to prevent iatrogenic vascular stenosis. Intentional transcatheter stent fracture (TSF) is an emerging alternative approach to stent transection, but little is known about the optimal stent substrate and best protocol to improve the likelihood of successful TSF. Bench testing was performed with a stent dilation protocol. After recording baseline characteristics, stents were serially or directly dilated using ultra-high-pressure balloons (UHPB) until fracture occurred or further stent dilation was not possible. Stent characteristics recorded were as follows: cell design, metallurgy, mechanism, and uniformity of fracture. Stents tested included bare-metal coronary stents, premounted small diameter stents, and ePTFE-covered small diameter premounted stents. Ninety-four stents representing 9 distinct models were maximally dilated, with 80 (85%) demonstrating evidence of fracture. Comprehensive fracture details were recorded in 64 stents: linear and complete in 34/64 stents (53.1%), linear and incomplete in 9/64 stents (14.1%), transverse/complex and complete in 6/64 stents (9.4%), and transverse/complex and incomplete in 15/64 stents (23.4%). Stent fracture was not accomplished in some stent models secondary to significant shortening, i.e., "napkin-ring" formation. Serial dilation resulted in evidence of fracture in 62/67 (92.5%) stents compared with 18/27 (66.7%) stents in the direct dilation group (p = 0.003). Intentional TSF is feasible in an ex vivo model. Serial dilation more reliably expanded the stent and allowed for ultimate stent fracture, whereas direct large diameter dilation of stents was more likely to generate a "napkin-ring" configuration, which may be more resistant to fracture. In vivo animal and human testing is necessary to

  18. Exclusion of Atherosclerotic Plaque from the Circulation Using Stent-Grafts: Alternative to Carotid Stenting with a Protection Device?

    SciTech Connect

    Peynircioglu, Bora Geyik, Serdar; Yavuz, Kivilcim; Cil, Barbaros E.; Saatci, Isil; Cekirge, Saruhan

    2007-09-15

    Purpose. To retrospectively assess the feasibility, safety, and clinical mid-term outcome of patients undergoing carotid artery stenting with stent-grafts. Methods. Over a 4 year period stent-grafts were used in the endovascular treatment of symptomatic internal carotid artery stenosis in 12 patients (2 women, 10 men, aged 47-83 (mean 64) years). Protection devices were not used. Possible microembolic complications were evaluated by magnetic resonance imaging (MRI) examinations of the brain before and the day after the procedure in all patients. Mean follow-up was 22 months (range 1-42 months), by Doppler ultrasonography and conventional angiography as well as clinical examination .Results. The technical success rate was 100%. A total of 13 coronary stent-grafts were used. The mean stenosis rate (in terms of diameter) was 85% and the mean length of stent-grafts used was 20.9 mm. The mean diameter to which the stent-grafts were dilated was 4.66 mm. In-hospital complications occurred in 1 patient who suffered a minor femoral access hematoma that did not require transfusion or surgical decompression. Post-stenting diffusion-weighted MRI revealed several ipsilateral silent microemboli in only 1 case, which was completely asymptomatic. Two patients had a major stroke after 2 years of follow-up. Restenosis was found in 2 patients who underwent successful balloon dilatation followed by placement of a self-expandable bare stent within the stent-grafts. Conclusions. Stent-grafts may prevent microembolic complications during stenting of atherosclerotic carotid lesions in selected cases, offering immediate exclusion of the atherosclerotic lesion from the circulation by pressing the plaque against the vessel wall. Comparative, randomized studies in larger series of patients are needed with carotid-dedicated stent-graft designs.

  19. Evaluation of the biocompatibility of two new diamond-like stent coatings (Dylyn) in a porcine coronary stent model.

    PubMed

    De Scheerder, I; Szilard, M; Yanming, H; Ping, X B; Verbeken, E; Neerinck, D; Demeyere, E; Coppens, W; Van de Werf, F

    2000-08-01

    Hydrogenated diamond-like carbon films (DLC, a-C:H), deposited using plasma-assisted or ion beam-assisted techniques, offer great potential as self-lubricating coatings in many tribological applications. Additionally, studies on biocompatibility have shown that DLC is an inert, impervious hydrocarbon with properties suitable for use in the biomedical field. One particular class of modified DLC coatings are diamond-like nanocomposite coatings (DLN or Dylyn , Bekaert, Kortrijk, Belgium), which offer promising solutions for many industrial applications. In this study, the biocompatibility of two diamond-like stent coatings are evaluated in a porcine coronary stent model. Either coated or non-coated stents were randomly implanted in two coronary arteries of 20 pigs so that each group contained 13 stented arteries. Pigs underwent a control angiogram at 6 weeks and were then sacrificed. Quantitative coronary analysis before, immediately after stent implantation, and at 6 weeks was performed using the semi-automated Polytron 1000 system (Siemens, Erlangen, Germany). Morphometry was performed using a computerized morphometric program. Angiographic analysis showed similar baseline selected arteries and post-stenting diameters. At 6-week follow-up, there was no significant difference in minimal stent diameter. Histopathology revealed a similar injury score in the 3 groups. Inflammation was significantly increased in the DLN-DLC coating group. Thrombus formation was significantly decreased in both coated stent groups. Neointimal hyperplasia was decreased in both coated stent groups; however, the difference with the non-coated stents was not statistically significant. Area stenosis was lower in the DLN-coated stent group than in the control group (41 +/- 17% vs. 54 +/- 15%; p = 0.06). The results indicate that the diamond-like nanocomposite stent coatings are compatible, resulting in decreased thrombogenicity and decreased neointimal hyperplasia. Covering this coating with

  20. Emergency coronary stenting with the Palmaz-Schatz stent for failed transluminal coronary angioplasty: results of a learning phase.

    PubMed

    Kiemeneij, F; Laarman, G J; van der Wieken, R; Suwarganda, J

    1993-07-01

    This study describes initial results of Palmaz-Schatz stent implantation in our department to restore and maintain vessel patency in 52 patients with obstructive dissection, defined as an intraluminal filling defect with coronary flow impairment after percutaneous transluminal coronary angioplasty (PTCA). The majority of patients (62%) underwent PTCA for unstable angina (n = 28), defined as angina at rest with documented ST segment changes resistant to nitrates, or acute myocardial infarction (n = 4). In six patients (11%) the stent could not be delivered. Seven of the remaining 46 patients (15%) had coronary artery bypass surgery performed because of increased risk for subacute stent occlusion, residual thrombosis, residual obstruction near the stent, coronary artery diameter less than 3.0 mm, or multiple and overlapping stents. One patient (3%) died in hospital from intracranial bleeding. Nine patients (23%) had subacute stent occlusion, retrospectively unpredictable in four patients. Nine of 29 patients (29%) with an uncomplicated clinical course after stenting had angiographic restenosis at a mean follow-up of 6.0 +/- 1.4 months (range 12 days to 8.3 months). Two patients (7%) died 3 months after successful stenting: one patient because of stent thrombosis after stopping warfarin before an abdominal operation and one patient after acute vascular surgery for late traumatic groin bleeding. Of the 39 medically treated patients with a stent, three (8%) had major bleeding complications. It is concluded that stent implantation is feasible in most patients with obstructive dissection after PTCA. After successful stent delivery, coronary flow is temporarily restored.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Design Optimisation of Coronary Artery Stent Systems.

    PubMed

    Bressloff, Neil W; Ragkousis, Giorgos; Curzen, Nick

    2016-02-01

    In recent years, advances in computing power and computational methods have made it possible to perform detailed simulations of the coronary artery stenting procedure and of related virtual tests of performance (including fatigue resistance, corrosion and haemodynamic disturbance). Simultaneously, there has been a growth in systematic computational optimisation studies, largely exploiting the suitability of surrogate modelling methods to time-consuming simulations. To date, systematic optimisation has focussed on stent shape optimisation and has re-affirmed the complexity of the multi-disciplinary, multi-objective problem at hand. Also, surrogate modelling has predominantly involved the method of Kriging. Interestingly, though, optimisation tools, particularly those associated with Kriging, haven't been used as efficiently as they could have been. This has especially been the case with the way that Kriging predictor functions have been updated during the search for optimal designs. Nonetheless, the potential for future, carefully posed, optimisation strategies has been suitably demonstrated, as described in this review.

  2. Drug-eluting stents below the knee.

    PubMed

    Bosiers, M; Deloose, K; Callaert, J; Keirse, K; Verbist, J; Peeters, P

    2011-04-01

    The fear that early thrombosis and late luminal loss due to intimal hyperplasia formation potentially leads to insufficient long-term patency rates can explain the reluctance on implanting stents in small diameter below-the-knee (BTK) arteries. Drug-eluting stent (DES) technology was developed to prevent early thrombosis and late luminal loss to potentially improve long-term patency rates. Currently, the first level 1 evidence from prospective, randomized, controlled DESTINY and ACHILLES studies indicate that the implantation of DES in short lesion lenghts in the infrapopliteal vasculature leads to favorable outcomes with high primary patency rates. This makes that primary DES placement can be recommended as treatment strategy in short BTK-lesions.

  3. A finite element strategy to investigate the free expansion behaviour of a biodegradable polymeric stent.

    PubMed

    Debusschere, Nic; Segers, Patrick; Dubruel, Peter; Verhegghe, Benedict; De Beule, Matthieu

    2015-07-16

    Bioresorbable stents represent a promising technological development within the field of cardiovascular angioplasty because of their ability to avoid long-term side effects of conventional stents such as in-stent restenosis, late stent thrombosis and fatigue induced strut fracture. Finite element simulations have proven to present a useful research tool for the design and mechanical analysis of stents. However, biodegradable stents pose new challenges because of their transitional mechanical behaviour. For polymeric biodegradable stents, viscoplastic effects have to be accounted for. This paper presents a method to analyse the mechanical behaviour of polymeric bioresorbable stents using an implicit finite-element solver. As an example, we investigate the mechanical behaviour of a commercially available bioresorbable stent. We examine how, due to the visco-elastic properties of the stent material, the balloon deployment rate influences the mechanical integrity of the stent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Mechanical characteristics of novel polyester/NiTi wires braided composite stent for the medical application

    NASA Astrophysics Data System (ADS)

    Zou, Qiuhua; Xue, Wen; Lin, Jing; Fu, Yijun; Guan, Guoping; Wang, Fujun; Wang, Lu

    Stents have been widely used in percutaneous surgery to treat stenosis diseases. The braided NiTi stent, as a promising prototype, still has limitations of low radial force and loose structure. In the present study, a newly integrated composite stent was designed and braided with NiTi wires and polyester multifilament yarns by textile technology. The mechanical properties of four composite stents and the control bare NiTi stent were evaluated by in vitro compression, bending and anti-torsion tests. The results showed that integrated polyester/NiTi composite stents were superior in radial support. The stents could keep patency even when highly curved and had lower stent straightening force. Composite stents with certain structure stayed stable under twisting. The configuration of NiTi wires in composite stents could significantly impact stent deformation under twisting.

  5. [Results of the upper digestive tract stenting with self-expanding stents].

    PubMed

    Fedorov, A G; Davydova, S V; Klimov, A E; Lebedev, N V

    2013-01-01

    The work is based on the analysis of the palliative treatment of 66 patients with malignant upper digestive tract obstruction who underwent implantation of 75 self-expanding metallic stents in the period of 2003-2012 yy. Early postoperative complications developed in 10 (15.2%) cases. Procedure-related complications were observed in 8 (12.1%) patients, non-specific complications occurred in 2 (3.0%) patients. In-hospital lethality was 4.5% (3 patients). 51 patients were followed until death. Symptomatic relapse of obstruction was observed in 4 cases. Median survival was 97 days. Stenting with self-expanding metal stents was concluded to be an effective and safe method of palliation of malignant upper digestive tract stenosis.

  6. Double-ended pigtail ureteral stent: useful modification to single end ureteral stent.

    PubMed

    Camacho, M F; Pereiras, R; Carrion, H; Bondhus, M; Politano, V A

    1979-05-01

    A newly created ureteral stenting catheter of double-ended pigtail design is introduced. The pigtail design at both ends maintains the catheter in place by serving as a solid anchoring device, both intravesically and within the renal pelvis; upward or downward migration of the stent is thus prevented. It is designed also to minimize trigonal irritation. The catheter can be introduced easily either cystoendoscopically or through a percutaneous antegrade route, or by a combination of both methods. It offers the additional advantage of being readily available from an inexpensive stock source; it may be quickly and easily custom made and shaped for any ureter by the physician immediately prior to its insertion. It thus avoids having to have premanufactured, more expensive ureteral stents of different lengths. Open surgery for upper urinary tract decompression can thus be avoided.

  7. Effect of Covered Metallic Stents Compared With Plastic Stents on Benign Biliary Stricture Resolution

    PubMed Central

    Coté, Gregory A.; Slivka, Adam; Tarnasky, Paul; Mullady, Daniel K.; Elmunzer, B. Joseph; Elta, Grace; Fogel, Evan; Lehman, Glen; McHenry, Lee; Romagnuolo, Joseph; Menon, Shyam; Siddiqui, Uzma D.; Watkins, James; Lynch, Sheryl; Denski, Cheryl; Xu, Huiping; Sherman, Stuart

    2017-01-01

    IMPORTANCE Endoscopic placement of multiple plastic stents in parallel is the first-line treatment for most benign biliary strictures; it is possible that fully covered, self-expandable metallic stents (cSEMS) may require fewer endoscopic retrograde cholangiopancreatography procedures (ERCPs) to achieve resolution. OBJECTIVE To assess whether use of cSEMS is noninferior to plastic stents with respect to stricture resolution. DESIGN, SETTING, AND PARTICIPANTS Multicenter (8 endoscopic referral centers), open-label, parallel, randomized clinical trial involving patients with treatment-naive, benign biliary strictures (N = 112) due to orthotopic liver transplant (n = 73), chronic pancreatitis (n = 35), or postoperative injury (n = 4), who were enrolled between April 2011 and September 2014 (with follow-up ending October 2015). Patients with a bile duct diameter less than 6 mm and those with an intact gallbladder in whom the cystic duct would be overlapped by a cSEMS were excluded. INTERVENTIONS Patients (N = 112) were randomized to receive multiple plastic stents or a single cSEMS, stratified by stricture etiology and with endoscopic reassessment for resolution every 3 months (plastic stents) or every 6 months (cSEMS). Patients were followed up for 12 months after stricture resolution to assess for recurrence. MAIN OUTCOMES AND MEASURES Primary outcome was stricture resolution after no more than 12 months of endoscopic therapy. The sample size was estimated based on the noninferiority of cSEMS to plastic stents, with a noninferiority margin of −15%. RESULTS There were 55 patients in the plastic stent group (mean [SD] age, 57 [11] years; 17 women [31%]) and 57 patients in the cSEMS group (mean [SD] age, 55 [10] years; 19 women [33%]). Compared with plastic stents (41/48, 85.4%), the cSEMS resolution rate was 50 of 54 patients (92.6%), with a rate difference of 7.2% (1-sided 95% CI, −3.0% to ∞; P < .001). Given the prespecified noninferiority margin of −15%, the

  8. Carotid artery stenting versus carotid endarterectomy.

    PubMed

    Nanna, Michael G; Gomes, Paulina; Njoh, Roland F; Ward, Charisse; Attaran, Robert R; Mena, Carlos

    2016-09-01

    Stroke remains a significant contributor to morbidity and mortality in developed countries. Carotid artery stenosis is a major cause of stroke. Advances in medical therapy, surgical technique and endovascular maturation has resulted in options for the treatment of carotid stenosis. Here, we present a review of carotid artery stenting and carotid endarterectomy as it applies to trials comparing and contrasting the two treatment options. We also explore the intricacies surrounding reimbursement of these treatment strategies in the USA.

  9. Simultaneous vertebral and subclavian artery stenting

    PubMed Central

    Tekieli, Łukasz; Machnik, Roman; Kabłak-Ziembicka, Anna; Przewłocki, Tadeusz; Paluszek, Piotr; Trystuła, Mariusz; Musiał, Robert; Dzierwa, Karolina; Pieniążek, Piotr

    2017-01-01

    Introduction Vertebrobasilar territory ischemia leads to disabling neurological symptoms and may be caused both by vertebral artery (VA) and subclavian artery (SA) stenosis. The coexisting symptomatic ipsilateral VA and proximal SA stenosis should be considered as a true bifurcation lesion for percutaneous treatment. Aim To evaluate the safety and efficacy of simultaneous angioplasty of vertebral and subclavian stenosis. Material and methods Fifteen patients (age 69.5 years, 46.7% men, all symptomatic from posterior circulation (history of stroke, transient ischemic attack, chronic ischemia symptoms)) were scheduled for simultaneous SA/VA angioplasty. Clinical and duplex ultrasound follow-up was conducted 1, 6 and 12 months after the procedure. Results The technical success rate was 100%. Single balloon-mounted stent angioplasty was performed for all VAs and for 13 (86.7%) SAs. In 4 cases a simultaneous radial and femoral approach was required. The mean North American Symptomatic Carotid Endarterectomy Trial (NASCET) VA stenosis was reduced from 88.7 ±9.7% to 5.7 ±6.8% and SA stenosis from 80 ±12.2% to 11 ±12.3% (p < 0.01). No periprocedural death, stroke, myocardial infarction or transient ischemic attack occurred. During follow-up (range: 6–107 months) in 10 of 15 (66.7%) patients relief of chronic ischemic symptoms was observed. No stroke/TIA occurred. One cardiovascular and 2 non-cardiovascular deaths were recorded. There was 1 symptomatic vertebral and 1 subclavian in-stent restenosis, and 2 cases of asymptomatic VA in-stent occlusion occurred. Conclusions Simultaneous vertebral and subclavian artery stenting is safe and effective. The restenosis rate remains at an acceptable level and it may be treated successfully with drug-eluting balloon angioplasty. In selected patients a dual radial and femoral approach may facilitate the procedure. PMID:28798785

  10. Reperfusion Hemorrhage Following Superior Mesenteric Artery Stenting

    SciTech Connect

    Moore, Michael; McSweeney, Sean; Fulton, Gregory; Buckley, John; Maher, Michael Guiney, Michael

    2008-07-15

    Percutaneous transluminal angioplasty and stent placement is now an established treatment option for chronic mesenteric ischemia and is associated with low mortality and morbidity rates. We present a case of reperfusion hemorrhage complicating endovascular repair of superior mesenteric artery stenosis. Although a recognized complication following repair of carotid stenosis, hemorrhage has not previously been reported following mesenteric endovascular reperfusion. We describe both spontaneous cessation of bleeding and treatment with coil embolization.

  11. Aspiration thrombectomy in concert with stent thrombectomy.

    PubMed

    Dumont, Travis M; Mokin, Maxim; Sorkin, Grant C; Levy, Elad I; Siddiqui, Adnan H

    2013-07-12

    In the SWIFT and TREVO 2 trials, aspiration thrombectomy was not able to be performed. Outside these studies, in post-market application, the interventionist can use aspiration thrombectomy in addition to stent device thrombectomy. This technique is described in detail in the present report. Combined aspiration/stentriever thrombectomy may improve recanalization efforts, simplify a second thrombectomy attempt if necessary and may limit distal embolization.

  12. Carotid Disease Management: Surgery, Stenting, or Medication.

    PubMed

    Khandelwal, Priyank; Chaturvedi, Seemant

    2015-09-01

    Internal carotid artery stenosis accounts for about 7-10 % of ischemic strokes. Conventional risk factors such as aging, hypertension, diabetes mellitus, and smoking increase the risk for carotid atherosclerosis. All patients with carotid stenosis should receive aggressive medical therapy. Carotid revascularization with either endarterectomy or stenting can benefit select patients with severe stenosis. New clinical trials will examine the contemporary role of carotid revascularization relative to optimal medical therapy.

  13. Particle Imaging Velocimetry Evaluation of Intracranial Stents in Sidewall Aneurysm: Hemodynamic Transition Related to the Stent Design

    PubMed Central

    Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Lovblad, Karl-Olof; Farhat, Mohamed; Pereira, Vitor Mendes

    2014-01-01

    We investigated the flow modifications induced by a large panel of commercial-off-the-shelf (COTS) intracranial stents in an idealized sidewall intracranial aneurysm (IA). Flow velocities in IA silicone model were assessed with and without stent implantation using particle imaging velocimetry (PIV). The use of the recently developed multi-time-lag method has allowed for uniform and precise measurements of both high and low velocities at IA neck and dome, respectively. Flow modification analysis of both regular (RSs) and flow diverter stents (FDSs) was subsequently correlated with relevant geometrical stent parameters. Flow reduction was found to be highly sensitive to stent porosity variations for regular stents RSs and moderately sensitive for FDSs. Consequently, two distinct IA flow change trends, with velocity reductions up to 50% and 90%, were identified for high-porosity RS and low-porosity FDS, respectively. The intermediate porosity (88%) regular braided stent provided the limit at which the transition in flow change trend occurred with a flow reduction of 84%. This transition occurred with decreasing stent porosity, as the driving force in IA neck changed from shear stress to differential pressure. Therefore, these results suggest that stents with intermediate porosities could possibly provide similar flow change patterns to FDS, favourable to curative thrombogenesis in IAs. PMID:25470724

  14. The use of a self-expandable stent with a self-expandable stent graft in a Fontan baffle.

    PubMed

    Choi, Eun Young; Lee, Kyung Suk; Song, Jin-young

    2013-02-01

    Intravascular or intracardiac stenosis occurs in various congenital heart diseases or after surgical repair. Although balloon angioplasty is the first option for relieving stenosis, frequently restenosis occurs because of elastic recoil or kingking component. The use of a self-expandable stent and covered stent in congenital heart disease has been reported for selected cases. In general, they have been performed for coarctation of the aorta or aortic aneurysm. We now report successful implantation of a self-expandable stent with a self-expandable covered stent graft in a case of lateral tunnel dehiscence with stenosis after a Fontan operation.

  15. Black hole restenosis after drug-eluting stent implantation for in-stent restenosis: potential mechanism and optimal strategy.

    PubMed

    Otsuka, Yoritaka; Murata, Takashi; Kono, Michiaki; Imoto, Hiroki; Koyama, Taku; Nakamura, Keita; Kadama, Sunao; Noguchi, Hiroo; Saito, Taro

    2015-09-01

    In-stent restenosis (ISR) has long remained as the major limitation of coronary stenting. The use of drug-eluting stent (DES) reduces the risk of repeat revascularization without an increase of death and myocardial infarction, compared to the standard bare metal stents. DES has also demonstrated markedly to reduce ISR for complex lesions. However, ISR after DES implantation still occurs and optimal treatment for ISR after DES has not been established. Herein, we report 3 cases with black hole restenosis confirmed by intravascular ultrasound at the site of overlapped DES and discuss potential mechanism and optimal strategy for this phenomenon.

  16. Investigation of Stent Implant Mechanics Using Linear Analytical and Computational Approach.

    PubMed

    Yang, Hua; Fortier, Aleksandra; Horne, Kyle; Mohammad, Atif; Banerjee, Subhash; Han, Hai-Chao

    2017-03-01

    Stent implants are essential in restoring normal blood flow in atherosclerotic arteries. Recent studies have shown high failure rates of stent implants in superficial femoral artery (SFA) as a result of dynamic loading environment imposed on the stent implants by the diseased arterial wall and turbulent blood flow. There are variety of stent designs and materials currently on the market however, there is no clear understanding if specific stent design is suitable with the material that is manufactured from and if this combination can sustain the life-cycle that the stent implants need to undergo once inside the artery. Lack of studies have been presented that relate stent mechanical properties with stent geometry and material used. This study presents linear theoretical and computational modeling approach that determines stent mechanical properties with effective stiffness of the deployed stent. Effective stiffness of the stent has been accurately derived based on stent structure design and loading in axial and radial directions. A rhombus stent structure was selected for this study due to its more common use and produced by main stream manufacturers. The derived theoretical model was validated using numerical finite element modeling approach. Results from this study can lead to preliminary insight towards understanding of stent deformation based on stent geometry, material properties and artery wall pressure; and how to carefully match stent's geometry with suitable material for long life cycle, increased strength, and reliable performance of stent implants.

  17. Braided thin-walled biodegradable ureteral stent: preliminary evaluation in a canine model.

    PubMed

    Zhang, Ming Qing; Zou, Ting; Huang, Yi Chen; Shang, Ya Feng; Yang, Gang Gang; Wang, Wen Zu; Zhou, Jun Mei; Wang, Lu; Chen, Fang; Xie, Hua

    2014-04-01

    To evaluate a novel designed degradable ureteral stent. A total of 24 male Beagles, each with bilateral stents implanted (a biodegradable ureteral 4.5-Fr stent and a standard 4-Fr biostable stent) were divided into four groups. Intravenous pyelography, B-mode ultrasonography, and blood and urine tests were carried out before the procedure (0 weeks), and at 1-, 2-, 3- and 4-week intervals. Meanwhile, the mechanical characteristics of stents were tested, and scanning electron microscopy images of the biodegradable braided stents were obtained at different time-points postoperatively. In addition, histopathological changes were compared between the two different stents. All biodegradable braided stents began degrading at 1 week, and had completely degraded by 4 weeks. Hydronephrosis was equivalent during the first 2 weeks, but less with the biodegradable stents than with the control biostable stents at 3 and 4 weeks. Preoperative and postoperative blood and urine results were similar. The mechanical properties of the biodegradable stents were better than conventional biostable stents. Scanning electron microscopy images obtained at different weekly intervals showed that stents degraded in a predictable fashion. Histological testing of the urinary tract showed that the stent-related tissue reactivity of the two different stents were similar. Our novel braided thin-walled biodegradable stents provide temporary renal drainage as good as commercially available biostable stents. They also have good biocompatibility and physical characteristics. Therefore, they might have clinical application. © 2013 The Japanese Urological Association.

  18. Impact of Coronary Plaque Characteristics on Late Stent Malapposition after Drug-Eluting Stent Implantation

    PubMed Central

    Hong, Sung-Jin; Kim, Byeong-Keuk; Shin, Dong-Ho; Kim, Jung-Sun; Ko, Young-Guk; Choi, Donghoon; Jang, Yangsoo

    2015-01-01

    Purpose To evaluate the impact of pre-procedural coronary plaque composition assessed by virtual histology intravascular ultrasound (VH-IVUS) on late stent malapposition assessed by optical coherence tomography (OCT) following drug-eluting stent (DES) implantation. Materials and Methods The study population consisted of 121 patients (121 lesions) who underwent both pre-procedural VH-IVUS and follow-up OCT after DES implantation. The association between pre-procedural plaque composition [necrotic core (NC), dense calcium (DC), fibrotic (FT), and fibro-fatty (FF) volumes] assessed by VH-IVUS and late stent malapposition (percent malapposed struts) or strut coverage (percent uncovered struts) assessed by follow-up OCT was evaluated. Results Pre-procedural absolute total NC, DC, FT, and FF plaque volumes were 22.9±19.0, 7.9±9.6, 63.8±33.8, and 16.5±12.4 mm3, respectively. At 6.3±3.1 months post-intervention, percent malapposed and uncovered struts were 0.8±2.5% and 15.3±16.7%, respectively. Pre-procedural absolute total NC and DC plaque volumes were positively correlated with percent malapposed struts (r=0.44, p<0.001 and r=0.45, p<0.001, respectively), while pre-procedural absolute total FT plaque volume was weakly associated with percent malapposed struts (r=0.220, p=0.015). Pre-procedural absolute total DC plaque volume was the only independent predictor of late stent malapposition on multivariate analysis (β=1.12, p=0.002). There were no significant correlations between pre-intervention plaque composition and percent uncovered struts. Conclusion Pre-procedural plaque composition was associated with late stent malapposition but not strut coverage after DES implantation. Larger pre-procedural absolute total DC plaque volumes were associated with greater late stent malapposition. PMID:26446634

  19. Stent-assisted coiling of wide-necked intracranial aneurysms using the Solitaire AB stent.

    PubMed

    Huded, Vikram; Nair, Rithesh R; Vyas, Devashish D; Chauhan, Bhumir N

    2014-07-01

    Stent-assisted coiling of wide-necked and complex intracranial aneurysms is an effective and feasible treatment option. The self-expanding, fully retrievable Solitaire AB (eV3, Irvine, CA, USA) stent is the latest neurovascular remodeling device available. To the best of our knowledge, there are no studies of Solitaire AB-assisted coiling of wide-necked intracranial aneurysms from India. Solitaire AB-assisted coiling of wide-necked intracranial aneurysms. The study was conducted in a tertiary care center with a dedicated Interventional Neurology division from 2009 to 2013. Consecutive patients with wide-necked aneurysms who underwent coiling assisted by the Solitaire AB stent were enrolled in the study. Axium 3D and Helix (eV3, Irvine, CA, USA) platinum coils were used to densely pack the aneurysm sac after deploying the stent across the neck. All patients were pretreated with antiplatelets according to protocol. Subsequently, dual antiplatelets were given for 6 months followed by continued aspirin. Outcome was assessed at 3 months using the modified Rankin Scale. Statistical analysis was done using the SPSS 17.0 software. A total of 16 patients underwent stent-assisted coiling. The most common site was the internal carotid artery (nine patients), median aneurysm size was 7 mm and median neck diameter was 5 mm. Thirteen patients presented with ruptured aneurysms. We achieved complete occlusion in all patients with no major complications. Thirteen patients were followed up, all have an mRS score of zero or one. We conclude that for wide-necked aneurysms, stent-assisted coiling using the Solitaire AB is a safe and effective treatment option.

  20. Stent selection in patients with myocardial infarction: drug eluting, biodegradable polymers or bare metal stents?

    PubMed

    Mieres, Juan; Rodríguez, Alfredo E

    2012-08-01

    Percutaneous coronary intervention (PCI) has been increasingly used in the last years during interventional procedures in patients with acute coronary syndromes (ACS) including ST elevation myocardial infarction (STEMI) and non-ST elevation myocardial infarction (NSTEMI). In patients with either STEMI, NSTEMI, high risk ACS with EKG changes or cardiac enzymes rises; PCI with bare metal stent (BMS) implantation has been associated with a significant improvement in clinical outcome. Therefore, BMS implantation during primary PCI in STEMI has become a standard of practice. With the introduction of drug eluting stents (DESs) in this decade, the use of these new devices instead of BMSs in patients with STEMI has emerged as a rational PCI alternative in this particular subgroup of patients. In spite of the unquestionable benefits of DESs in terms of reduction of restenosis and TVR, specific concerns have arisen with regard to their long-term safety. High incidence of very late stent thrombosis has been described with these devices, and special attention should be paid in patients with unstable coronary lesions, in which plaque composition and remodeling may play a main role in their safety and long-term outcome. Intraluminal thrombus caused by plaque rupture is the most frequent mechanism of STEMI, in which the necrotic core and thin fibrous cap play a major role. In this context, the use of first DESs designs may be futile or even unsafe because delayed healing may further contribute to plaque instability. Adjunctive invasive imaging tools can improve stent deployment and safety outcome in these lesions with intravascular findings of plaque instability. Recently, other players such as new dedicated antithrombotic BMS designs, including selfexpanding stents or drug-eluting coated balloons, are exploring their potential indications in patients with ACS and myocardial infarction. This paper reports and discusses new stent devices and adjunctive pharmacologic agents. It

  1. Safety and Efficacy of New Sirolimus-eluting Stent Models in a Preclinical Study.

    PubMed

    Estévez-Loureiro, Rodrigo; Pérez de Prado, Armando; Pérez-Martínez, Claudia; Cuellas-Ramón, Carlos; Regueiro-Purriños, Marta; Gonzalo-Orden, José M; López-Benito, María; Molina-Crisol, María; Duocastella-Codina, Luis; Fernández-Vázquez, Felipe

    2015-12-01

    Initial preclinical studies are required during the process of improving polymers, platforms, and drug-eluting systems for new coronary stent designs. Our objective was to analyze the efficacy and safety of new drug-eluting stent models compared with a conventional stent and commercialized drug-eluting stents in an experimental model with healthy porcine coronary arteries. Sixty stents (conventional stent, new sirolimus-eluting stents: drug-eluting stents 1, 2 and 3; Cypher(®) and Xience(®)) were randomly placed in the coronary arteries of 20 Large White domestic pigs. Angiographic and histomorphometric studies were done 28 days later. The stents were implanted at a stent/artery ratio of 1.34±0.15, with no significant differences between groups. The new stents showed less late loss and angiographic restenosis than conventional stents (P=.006 and P<.001, respectively). Histologically, restenosis and neointimal area were lower with all the new platforms than with the conventional stents (P<.001 for each variable), and no differences were found vs the drug-eluting stents on the market. Safety data showed that endothelialization was lower with drug-eluting stents than with conventional stents, except for drug-eluting stent 3 (P=.084). Likewise, inflammation was lower with drug-eluting stent 3 than with other stents. The new drug-eluting stent platforms studied are associated with less restenosis than conventional stents and showed no significant differences in safety or efficacy vs commercialized drug-eluting stents. Copyright © 2015 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  2. Application of a mechanobiological simulation technique to stents used clinically.

    PubMed

    Boyle, Colin J; Lennon, Alex B; Prendergast, Patrick J

    2013-03-15

    Many cardiovascular diseases are characterised by the restriction of blood flow through arteries. Stents can be expanded within arteries to remove such restrictions; however, tissue in-growth into the stent can lead to restenosis. In order to predict the long-term efficacy of stenting, a mechanobiological model of the arterial tissue reaction to stress is required. In this study, a computational model of arterial tissue response to stenting is applied to three clinically relevant stent designs. We ask the question whether such a mechanobiological model can differentiate between stents used clinically, and we compare these predictions to a purely mechanical analysis. In doing so, we are testing the hypothesis that a mechanobiological model of arterial tissue response to injury could predict the long-term outcomes of stent design. Finite element analysis of the expansion of three different stent types was performed in an idealised, 3D artery. Injury was calculated in the arterial tissue using a remaining-life damage mechanics approach. The inflammatory response to this initial injury was modelled using equations governing variables which represented tissue-degrading species and growth factors. Three levels of inflammation response were modelled to account for inter-patient variability. A lattice-based model of smooth muscle cell behaviour was implemented, treating cells as discrete agents governed by local rules. The simulations predicted differences between stent designs similar to those found in vivo. It showed that the volume of neointima produced could be quantified, providing a quantitative comparison of stents. In contrast, the differences between stents based on stress alone were highly dependent on the choice of comparison criteria. These results show that the choice of stress criteria for stent comparisons is critical. This study shows that mechanobiological modelling may provide a valuable tool in stent design, allowing predictions of their long

  3. A case of active peri-stent inflammation after sirolimus-eluting stent implantation.

    PubMed

    Kurosawa, Takafumi; Kotani, Jun-Ichi; Matsuyama, Taka-aki; Ishibashi-Ueda, Hatsue

    2015-03-01

    We report an autopsy case of a coronary aneurysm with massive adventitial inflammation post-percutaneous coronary intervention with sirolimus-eluting stent (SES) insertion in the left circumflex (LCX) coronary artery for ischemic heart disease 3 years prior to death. The internal elastic membrane was disrupted opposite the site of the eccentric LCX plaque due to injury during stenting, and the adventitia showed massive inflammatory cell infiltration, mainly consisting of eosinophils. The LCX showed aneurysmal dilatation with inflammatory cell infiltration. Inappropriate SES implantation attracted chronic inflammation. Chronic inflammation can lead to the development of coronary artery aneurysms.

  4. Role of metallic stents in benign esophageal stricture

    NASA Astrophysics Data System (ADS)

    Shim, Chan Sup

    2012-10-01

    Simple esophageal strictures, which are focal, straight, and large in diameter, usually require 1 - 3 dilation sessions to relieve symptoms. However, complex strictures, which are long, tortuous, or associated with a severely compromised luminal diameter, are usually more difficult to treat with conventional bougie or balloon dilation techniques, and often have high recurrence rates. Although the permanent placement of self-expandable metal stents (SEMS) has been used to manage refractory benign esophageal strictures, this procedure is associated with additional problems, such as stricture from tissue hyperplasia, stent migration, and fistula formation. Thus, several new types of stents have been developed, including temporary SEMS, self-expandable plastic stents (SEPS), and biodegradable stents. The use of these new products has produced varied results. Temporary SEMS that have been used to relieve benign esophageal conditions have caused granulation tissue at both ends of the stent because of contact between the mucosa and the exposed metal components of the stent, thus hindering stent removal. We examined the tissue response to two new types of SEMS, a flange-type and a straighttype, each coated with a silicone membrane on the outside of the metal mesh. These two SEMS were evaluated individually and compared with a conventional control stent in animal experiments. Although the newly designed stents resulted in reduced tissue hyperplasia, and were thus more easily separated from the esophageal tissue, some degree of tissue hyperplasia did occur. We suggest that newly designed DES (drug-eluting stents) may provide an alternative tool to manage refractory benign esophageal stricture.

  5. Magnetizable stent-grafts enable endothelial cell capture

    NASA Astrophysics Data System (ADS)

    Tefft, Brandon J.; Uthamaraj, Susheil; Harburn, J. Jonathan; Hlinomaz, Ota; Lerman, Amir; Dragomir-Daescu, Dan; Sandhu, Gurpreet S.

    2017-04-01

    Emerging nanotechnologies have enabled the use of magnetic forces to guide the movement of magnetically-labeled cells, drugs, and other therapeutic agents. Endothelial cells labeled with superparamagnetic iron oxide nanoparticles (SPION) have previously been captured on the surface of magnetizable 2205 duplex stainless steel stents in a porcine coronary implantation model. Recently, we have coated these stents with electrospun polyurethane nanofibers to fabricate prototype stent-grafts. Facilitated endothelialization may help improve the healing of arteries treated with stent-grafts, reduce the risk of thrombosis and restenosis, and enable small-caliber applications. When placed in a SPION-labeled endothelial cell suspension in the presence of an external magnetic field, magnetized stent-grafts successfully captured cells to the surface regions adjacent to the stent struts. Implantation within the coronary circulation of pigs (n=13) followed immediately by SPION-labeled autologous endothelial cell delivery resulted in widely patent devices with a thin, uniform neointima and no signs of thrombosis or inflammation at 7 days. Furthermore, the magnetized stent-grafts successfully captured and retained SPION-labeled endothelial cells to select regions adjacent to stent struts and between stent struts, whereas the non-magnetized control stent-grafts did not. Early results with these prototype devices are encouraging and further refinements will be necessary in order to achieve more uniform cell capture and complete endothelialization. Once optimized, this approach may lead to more rapid and complete healing of vascular stent-grafts with a concomitant improvement in long-term device performance.

  6. Stenting for Obstructing Colon Cancer: Fewer Complications and Colostomies

    PubMed Central

    Miller, Peter; Goldstein, Rachel; Coury, Joseph; Hackford, Alan; Dao, Haisar

    2015-01-01

    Background and Objectives: Colonic stenting has been used in the setting of malignant obstruction to avoid an emergent colectomy. We sought to determine whether preoperative placement of a colonic stent decreases morbidity and the rate of colostomy formation. Methods: Cases of obstructing sigmoid, rectosigmoid, and rectal cancer from January 1, 2010, to December 31, 2011, were identified in the Nationwide Inpatient Sample (NIS) database. All patients were treated at hospitals in the United States, and the database generated national estimates. Postoperative complications, mortality, and the rate of colostomy formation were analyzed. Results: Of the estimated 7891 patients who presented with obstructing sigmoid, rectosigmoid, or rectal cancer necessitating intervention, 12.1% (n = 956) underwent placement of a colonic stent, and the remainder underwent surgery without stent placement. Of the patients who underwent stenting, 19.9% went on to have colon resection or stoma creation during the same admission. Patients who underwent preoperative colonic stent placement had a lower rate of total postoperative complications (10.5% vs 21.7%; P < .01). There was no significant difference in mortality (4.7% vs 4.2%; P = .69). The rate of colostomy formation was more than 2-fold higher in patients who did not undergo preoperative stenting (42.5% vs 19.5%; P < .01). Preoperative stenting was associated with increased use of laparoscopy (32.6% vs 9.7%; P < .01). Conclusions: Our study characterizes the national incidence of preoperative placement of a colonic stent in the setting of malignant obstruction. Preoperative stent placement is associated with lower postoperative complications and a lower rate of colostomy formation. The results support the hypothesis that stenting as a bridge to surgery may benefit patients by converting an emergent surgery into an elective one. PMID:25848200

  7. Coronary Stent Materials and Coatings: A Technology and Performance Update.

    PubMed

    O'Brien, Barry; Zafar, Haroon; Ibrahim, Ahmad; Zafar, Junaid; Sharif, Faisal

    2016-02-01

    This paper reviews the current state of the art for coronary stent materials and surface coatings, with an emphasis on new technologies that followed on from first-generation bare metal and drug-eluting stents. These developments have been driven mainly by the need to improve long term outcomes, including late stent thrombosis. Biodegradable drug-eluting coatings aim to address the long term effects of residual durable polymer after drug elution; the SYNERGY, BioMatrix, and Nobori stents are all promising devices in this category, with minimal polymer through the use of abluminal coatings. Textured stent surfaces have been used to attached drug directly, without polymer; the Yukon Choice and BioFreedom stents have some promising data in this category, while a hydroxyapatite textured surface has had less success. The use of drug-filled reservoirs looked promising initially but the NEVO device has experienced both technical and commercial set-backs. However this approach may eventually make it to market if trials with the Drug-Filled Stent prove to be successful. Non-pharmacological coatings such as silicon carbide, carbon, and titanium-nitride-oxide are also proving to have potential to provide better performance than BMS, without some of the longer term issues associated with DES. In terms of biological coatings, the Genous stent which promotes attachment of endothelial progenitor cells has made good progress while gene-eluting stents still have some practical challenges to overcome. Perhaps the most advancement has been in the field of biodegradable stents. The BVS PLLA device is now seeing increasing clinical use in many complex indications while magnesium stents continue to make steady advancements.

  8. Virtual stenting of intracranial aneurysms: application of hemodynamic modification analysis.

    PubMed

    Song, Yunsun; Choe, Jooae; Liu, Hairi; Park, Kye Jin; Yu, HyungBin; Lim, Ok Kyun; Kim, Hyoweon; Park, Darlene; Ge, Jiajia; Suh, Dae Chul

    2016-08-01

    Practical application of hemodynamic modification analysis based on computational fluid dynamics (CFD) in intracranial aneurysms is still under study. To determine the clinical applicability of virtual stenting of aneurysms by comparing the simulated results with clinical outcome of real stenting. Three-dimensional (3D) digital subtraction angiography (DSA) images were imported to a dedicated integrated prototypic CFD platform (Siemens Healthcare GmbH) which allows all necessary steps of 3D models for CFD analysis. The results of CFD simulation with virtual implantation of a stent can be visualized in the same platform for qualitative comparisons on a color-coded volume visualization window. Five small intracranial aneurysms with and without virtual stenting were analyzed and assessed on a qualitative level. Expert rating were performed for evaluating the simulated results, and comparing those to the long-term follow-up outcomes of real stenting. CFD simulation after virtual stenting was feasible in five differently located aneurysms and corresponded to the long-term changes of stented aneurysms by showing alteration in flow pattern. There was no significant difference (P = 0.5) between the simulated hemodynamic changes after virtual stenting and the angiographic changes after stenting in four aneurysms except one. There was good agreement regarding the assessment of the changes by two raters (kappa = 0.657). CFD analysis using patient-specific virtual stenting of the CFD platform may be used as a simple and less time-consuming test tool predicting the involution of aneurysms after stent placement by analyzing the vector visualization of the flow changes. © The Foundation Acta Radiologica 2015.

  9. [Biodegradable catheters and urinary stents. When?

    PubMed

    Soria, F; Morcillo, E; López de Alda, A; Pastor, T; Sánchez-Margallo, F M

    2016-10-01

    One of the main wishes in the field of urinary catheters and stents is to arm them with biodegradable characteristics because we consider a failure of these devices the need for retrieval, the forgotten catheter syndrome as well as the adverse effects permanent devices cause after fulfilling their aim. The efforts focused in new designs, coatings and biomaterials aim to increase the biocompatibility of theses internal devices. Lately, there have been correct advances to answer the main challenges regarding biodegradable ureteral devices. Thus, modulation of the rate of degradation has been achieved thanks to new biomaterials and the use of copolymers that enable to choose the time of permanence as it is programmed with conventional double J catheters. Biocompatibility has improved with the use of new polymers that adapt better to the urine. Finally, one of the main problems is elimination of degraded fragments and experimentally it has be demonstrated that new designs elicit controlled degradation, from distal to proximal; using stranding and combination of copolymers degradation may be caused by dilution, reducing fragmentation to the last stages of life of the prosthesis. Moreover, it has been demonstrated that biodegradable catheters potentially may cause less urinary tract infection, less encrustation and predictably they will diminish catheter morbidity, since their degradation process reduces adverse effects. Regarding the development of biodegradable urethral stents, it is necessary to find biomaterials that enable maintaining their biomechanical properties in the long term, keeping open the urethral lumen both in patients with BPH and urethral stenosis. Modulation of the time of degradation of the prosthesis has been achieved, but the appearance of urothelial hyperplasia is still a constant in the initial phases after implantation. The development of drug eluting stents, anti-proliferative or anti-inflammatory, as well as biodegradable stents biocoated is a

  10. Balloon-expandable covered stent therapy of complex endovascular pathology.

    PubMed

    Giles, Heath; Lesar, Christopher; Erdoes, Luke; Sprouse, Richard; Myers, Stuart

    2008-11-01

    The current study was designed to investigate our hypotheses that balloon-expandable covered stents display acceptable function over longitudinal follow-up in patients with complex vascular pathology and provide a suitable alternative for the treatment of recurrent in-stent restenosis. All stents were Atrium iCast, which is a balloon-mounted, polytetrafluoroethylene-covered stent with a 6F/7F delivery system. A retrospective review was performed of 49 patients with 66 stented lesions. Data were analyzed with life tables and t-tests. The most commonly treated vessels were the iliac (61%) and renal (24%) arteries. Indications for covered stent placement were unstable atheromatous lesions (50%), recurrent in-stent restenosis (24%), aneurysm (8%), aortic bifurcation reconstruction (7.5%), dissection (4.5%), endovascular aneurysm repair-related (4.5%), and stent fracture (1.5%). Patency was assessed by angiogram or duplex ultrasonography. The primary end point was patency and secondary end points were technical success and access-site complications. Mean follow-up was 13 months (range 1.5-25). The technical success rate was 97%. Unsuccessful outcomes were due to deployment error (n=1) and stent malpositioning (n=1). The cohort (n=64) 6- and 12-month primary patency rates were 96% and 84%, respectively. Twelve-month assisted primary patency was 98%. Iliac artery stents (n=38) had a primary patency of 97% at 6 months and 84% at 12 months with an assisted primary patency of 100% at 12 months. Renal artery stents (n=16) had a primary patency of 92% at 6 months and 72% at 12 months with an assisted primary patency of 92% at 6 and 12 months. Stents placed for recurrent in-stent restenosis (n=16) had a primary patency of 85%, assisted primary patency of 93%, and a 15% restenosis rate at 12 months. Specifically, stents placed for renal artery recurrent in-stent restenosis (n=10) had a primary patency of 73%, assisted primary patency of 82%, and a restenosis rate of 27%. The

  11. Cost comparison between two modes of Palmaz Schatz coronary stent implantation: transradial bare stent technique vs. transfemoral sheath-protected stent technique.

    PubMed

    Kiemeneij, F; Hofland, J; Laarman, G J; van der Elst, D H; van der Lubbe, H

    1995-08-01

    Coronary Palmaz Schatz stent implantation is usually performed by using the sheath protected stent delivery system (SDS) via the percutaneous transfemoral route. However, downsizing of PTCA equipment made transradial coronary stenting feasible. Bare stent implantation, 6F technique, increased patient mobility, reduced vascular complications and reduced hospital stay may increase cost effectiveness of this novel technique. Two well-documented patient groups selected for elective single vessel and single lesion Palmaz Schatz stent implantation were retrospectively compared. Group A (transradial stenting; n = 35) was compared to Group B (transfemoral stenting; n = 25) derived from the Benestent population, included in our hospital. A comparison was made for three areas of interest: (1) procedural consumption of material (the number of guiding catheters, guidewires, balloon catheters and stents), (2) postprocedural need for diagnostic and therapeutic procedures for stent-related complications, and (3) duration of hospital stay. Differences between these subjects in Group A and B were translated to hospital costs. Although more guiding catheters were used in group A (1.69 +/- 0.87 vs. 1.08 +/- 0.28; P = 0.001), the use of the SDS contributed importantly to higher material costs in group B (cost reduction in group A; 13%). Less patients in group A required diagnostic (2 vs. 7; P = 0.027) and therapeutic (0 vs. 5; P = 0.01) procedures for bleeding complications (cost reduction; 93%). Hospitalization in Group A was shorter (6.4 +/- 4.7 vs. 11.6 +/- 9.9 days; P = 0.005), caused by early and safe mobilization, less vascular complications, and preprocedural adjustment on coumadin (cost reduction; 45%).(ABSTRACT TRUNCATED AT 250 WORDS)

  12. [A case of severe motor and intellectual disability with tracheal stenosis due to granulation caused by metal stents treated successfully by silicone stents].

    PubMed

    Kotani, Haruko; Hino, Hiroyuki; Shiraishi, Taisuke; Ogura, Hideo

    2002-11-01

    A silicone stent (Dumon stent) was used in a severe motor and intellectual disability with severe tracheal stenosis due to granulation caused by an implanted the expanded metal stent (Ultraflex Nitinol Stent). To treat tracheobronchial malacia, diagnosed in infancy, expanded metalic stent was implanted at the ages of 30 and 32 years. However, a few months after the second implantation, progressive dyspnea appeared, and he had to use a respirator under intravenous anesthesia. Bronchoscopy showed re-stenosis of the trachea due to a granulation tissue within the stent. A Dumon stent was applied to control the re-stenosis. He was successfully weaned from a respirator. Since granulation tissue had recurred at the end of the Dumon stent after 3 months, a long term care of the airway and regular observation is necessary after implantation of stents.

  13. Fibrin-film stenting in a porcine coronary injury model: efficacy and safety compared with uncoated stents.

    PubMed

    McKenna, C J; Camrud, A R; Sangiorgi, G; Kwon, H M; Edwards, W D; Holmes, D R; Schwartz, R S

    1998-05-01

    This study was designed to test the efficacy and safety of a fibrin-film-covered stent compared with that of a bare metal stent in the porcine coronary injury model. Biodegradable stents are a potential method of achieving total lesion coverage and delivering local, lesion-specific drug therapy. Two coronary arteries in each pig were randomly assigned to deployment of either a fibrin-film or a bare tantalum wire-coil stent. An oversized balloon injury, 1.15 to 1.30 times the reference vessel diameter, was induced in each coronary segment before stenting to simulate angioplasty injury. Thirty pigs were studied: group 1 for 28 days (15 pigs); group 2 for 90 days (5 pigs); group 3 for 6 months (5 pigs); group 4 for 1 year (5 pigs). Two pigs died of occlusion of the bare stent and one of occlusion of the fibrin stent (p > 0.99). There were no significant differences between the fibrin-stented and bare-stented coronary segments with regard to arterial injury. In group 1 (28 days, 14 pigs), the mean neointimal thicknesses in the fibrin-stented and bare-stented groups were 0.57+/-0.31 and 0.57+/-0.27 mm, respectively (p=0.89). In groups 2 to 4 (90 days, four pigs; 6 months, four pigs; 1 year, five pigs), the mean neointimal thicknesses for fibrin- and bare-stented coronary segments at the times studied were 0.48+/-0.26 versus 0.50+/-0.22 mm at 90 days; 035+/-0.04 versus 0.35+/-0.16 mm at 6 months; and 0.33+/-0.14 versus 0.30+/-0.14 mm at 1 year (p=0.98). Fibrin-film stents appear to be an excellent candidate for local drug delivery because they can completely and safely cover the stented coronary segment while degrading slowly over 1 to 3 months. This result is important when compared with the poor results of previous studies of synthetic polymer stents.

  14. Endothelial cell repopulation after stenting determines in-stent neointima formation: effects of bare-metal vs. drug-eluting stents and genetic endothelial cell modification

    PubMed Central

    Douglas, Gillian; Van Kampen, Erik; Hale, Ashley B.; McNeill, Eileen; Patel, Jyoti; Crabtree, Mark J.; Ali, Ziad; Hoerr, Robert A.; Alp, Nicholas J.; Channon, Keith M.

    2013-01-01

    Aims Understanding endothelial cell repopulation post-stenting and how this modulates in-stent restenosis is critical to improving arterial healing post-stenting. We used a novel murine stent model to investigate endothelial cell repopulation post-stenting, comparing the response of drug-eluting stents with a primary genetic modification to improve endothelial cell function. Methods and results Endothelial cell repopulation was assessed en face in stented arteries in ApoE−/− mice with endothelial-specific LacZ expression. Stent deployment resulted in near-complete denudation of endothelium, but was followed by endothelial cell repopulation, by cells originating from both bone marrow-derived endothelial progenitor cells and from the adjacent vasculature. Paclitaxel-eluting stents reduced neointima formation (0.423 ± 0.065 vs. 0.240 ± 0.040 mm2, P = 0.038), but decreased endothelial cell repopulation (238 ± 17 vs. 154 ± 22 nuclei/mm2, P = 0.018), despite complete strut coverage. To test the effects of selectively improving endothelial cell function, we used transgenic mice with endothelial-specific overexpression of GTP-cyclohydrolase 1 (GCH-Tg) as a model of enhanced endothelial cell function and increased NO production. GCH-Tg ApoE−/− mice had less neointima formation compared with ApoE−/− littermates (0.52 ± 0.08 vs. 0.26 ± 0.09 mm2, P = 0.039). In contrast to paclitaxel-eluting stents, reduced neointima formation in GCH-Tg mice was accompanied by increased endothelial cell coverage (156 ± 17 vs. 209 ± 23 nuclei/mm2, P = 0.043). Conclusion Drug-eluting stents reduce not only neointima formation but also endothelial cell repopulation, independent of strut coverage. In contrast, selective targeting of endothelial cell function is sufficient to improve endothelial cell repopulation and reduce neointima formation. Targeting endothelial cell function is a rational therapeutic strategy to improve vascular healing and decrease neointima formation

  15. Biodegradable Metals for Cardiovascular Stent Application: Interests and New Opportunities

    PubMed Central

    Moravej, Maryam; Mantovani, Diego

    2011-01-01

    During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6–12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals. PMID:21845076

  16. Are antibiotics necessary during routine cystoscopic stent removal?

    PubMed Central

    Han, Allison; McDonald, Michelle; Lakin, Charlie

    2016-01-01

    Background The 2008 American Urological Association (AUA) Best Practice Statement on antimicrobial prophylaxis states that prophylaxis is not warranted for subjects with normal risk profile undergoing cystourethroscopy unless manipulation such as ureteral stent removal is performed. To date no studies have specifically assessed the need for antimicrobial prophylaxis during cystoscopic ureteral stent removal. We sought to determine the risk of infectious complications following cystoscopic stent removal with and without antimicrobial prophylaxis. Methods A retrospective review identified 70 subjects who underwent cystoscopic ureteral stent removal following kidney stone treatment, under the care of two separate urologists with differing practice patterns. Each cohort consisted of 35 subjects: with and without prophylactic antibiotics. Clinical variables assessed included demographics, type of stone intervention, prior urinary tract infection (UTI) history, immunocompromising comorbidities, antimicrobial class at time of stone intervention, and antimicrobial administration at cystoscopic stent removal. The primary outcome assessed was development of symptomatic UTI within 4 weeks after stent removal. Results Overall, 35 patients (50%) received antimicrobial prophylaxis at the time of stent removal and 35 (50%) did not receive antimicrobial prophylaxis, with no demographic or clinical differences between cohorts. Two patients in the antimicrobial cohort (6%) developed a UTI and none of the patients who did not receive antimicrobial prophylaxis developed a UTI (P=0.15). Conclusions In our cohort study antimicrobial prophylaxis at the time of cystoscopic stent removal did not appear to provide a significant benefit in UTI prevention. Prospective studies would assist in validating these findings. PMID:27785437

  17. Breakthrough: NETL's Research Saving Lives with Coronary Stents

    ScienceCinema

    Turner, Paul

    2016-07-12

    NETL's Albany location is world renown for its expertise in materials research. One recent offshoot of this expertise was the assistance in developing a new material for coronary stents. This research led to the development of a stent which now has a 33% global market share and has produced over four hundred sustainable jobs in the United States.

  18. Breakthrough: NETL's Research Saving Lives with Coronary Stents

    SciTech Connect

    Turner, Paul

    2012-11-26

    NETL's Albany location is world renown for its expertise in materials research. One recent offshoot of this expertise was the assistance in developing a new material for coronary stents. This research led to the development of a stent which now has a 33% global market share and has produced over four hundred sustainable jobs in the United States.

  19. Biodegradable metals for cardiovascular stent application: interests and new opportunities.

    PubMed

    Moravej, Maryam; Mantovani, Diego

    2011-01-01

    During the last decade, biodegradable metallic stents have been developed and investigated as alternatives for the currently-used permanent cardiovascular stents. Degradable metallic materials could potentially replace corrosion-resistant metals currently used for stent application as it has been shown that the role of stenting is temporary and limited to a period of 6-12 months after implantation during which arterial remodeling and healing occur. Although corrosion is generally considered as a failure in metallurgy, the corrodibility of certain metals can be an advantage for their application as degradable implants. The candidate materials for such application should have mechanical properties ideally close to those of 316L stainless steel which is the gold standard material for stent application in order to provide mechanical support to diseased arteries. Non-toxicity of the metal itself and its degradation products is another requirement as the material is absorbed by blood and cells. Based on the mentioned requirements, iron-based and magnesium-based alloys have been the investigated candidates for biodegradable stents. This article reviews the recent developments in the design and evaluation of metallic materials for biodegradable stents. It also introduces the new metallurgical processes which could be applied for the production of metallic biodegradable stents and their effect on the properties of the produced metals.

  20. Escape from true stent jail by use of the rotablator.

    PubMed

    Mushahwar, S S; Ramsdale, D R

    2000-02-01

    We describe the use of the Rotablator device to allow sidebranch access via the side-wall of a stent when it has proved impossible to pass even the lowest profile balloon catheter through the struts N a situation of "true stent jail".

  1. Duplex Ultrasonography in Assessing Restenosis of Renal Artery Stents

    SciTech Connect

    Bakker, Jeannette; Beutler, Jaap J.; Elgersma, Otto E.H.; Lange, Eduard E. de; Kort, Gerard A.P. de; Beek, Frederik J. A.

    1999-11-15

    Purpose: To determine the accuracy and optimal threshold values of duplex ultrasonography (US) in assessing restenosis of renal artery stents. Methods: Twenty-four consecutive patients with 33 renal arteries that had previously been treated with placement of a Palmaz stent underwent duplex US prior to intraarterial digital subtraction angiography (DSA), which was the reference standard. Diagnostic accuracy of in-stent peak systolic velocity (PSV) and reno-aortic ratio (RAR = PSV renal stent/PSV aorta) in detecting > 50% in-stent restenosis were evaluated by the receiver operating characteristic curve. Sensitivity and specificity were determined using the optimal threshold values, and using published threshold values: RAR > 3.5 and in-stent PSV > 180 cm/sec. Results: Six examinations were technically inadequate. Nine stents had residual or restenosis > 50% at DSA. The two duplex parameters were equally accurate since areas under the curves were similar (0.943). With optimal threshold values of 226 cm/sec for PSV and 2.7 for RAR, sensitivities and specificities were 100% and 90%, and 100% and 84%, respectively. Using the published duplex criteria resulted in sensitivities and specificities of 100% and 74% for PSV, and 50% and 89% for RAR. Conclusion: Duplex US is a sensitive modality for detecting in-stent restenosis if laboratory-specific threshold values are used.

  2. Innovation in aortoiliac stenting: an in vitro comparison

    NASA Astrophysics Data System (ADS)

    Groot Jebbink, E.; Goverde, P. C. J. M.; van Oostayen, J. A.; Reijnen, M. M. P. J.; Slump, C. H.

    2014-03-01

    Aortoiliac occlusive disease (AIOD) may cause disabling claudicatio, due to progression of atherosclerotic plaque. Bypass surgery to treat AIOD has unsurpassed patency results, with 5-year patency rates up to 86%, at the expense of high complication rates (local and systemic morbidity rate of 6% and 16%). Therefore, less invasive, endovascular treatment of AOID with stents in both iliac limbs is the first choice in many cases, however, with limited results (average 5-year patency: 71%, range: 63-82%). Changes in blood flow due to an altered geometry of the bifurcation is likely to be one of the contributing factors. The aim of this study is to compare the geometry and hemodynamics of various aortoiliac stent configurations in vitro. Transparent vessel phantoms mimicking the anatomy of the aortoiliac bifurcation are used to accommodate stent configurations. Bare Metal Kissing stents (BMK), Kissing Covered (KC) stents and the Covered Endovascular Reconstruction of the Aortic Bifurcation (CERAB) configuration are investigated. The models are placed inside a flow rig capable of simulating physiologic relevant flow in the infrarenal area. Dye injection reveals flow disturbances near the neobifurcation of BMK and KC stents as well. At the radial mismatch areas of the KC stents recirculation zones are observed. With the CERAB configuration no flow reversal or large disturbances are observed. In conclusion, dye injection reveals no significant flow disturbances with the new CERAB configuration as seen with the KC and BMK stents.

  3. Stents for the prevention of pancreatic fistula following pancreaticoduodenectomy.

    PubMed

    Dong, Zhiyong; Xu, Jing; Wang, Zhen; Petrov, Maxim S

    2016-05-06

    Several studies have demonstrated that the use of pancreatic duct stents following pancreaticoduodenectomy is associated with a lower risk of pancreatic fistula. However, to date there is a lack of accord in the literature on whether the use of stents is beneficial and, if so, whether internal or external stenting, with or without replacement, is preferable. This is an update of a systematic review. To determine the efficacy of pancreatic stents in preventing pancreatic fistula after pancreaticoduodenectomy. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science, and four major Chinese biomedical databases up to November 2015. We also searched several major trials registers. Randomized controlled trials (RCTs) comparing the use of stents (either internal or external) versus no stents, and comparing internal stents versus external stents, replacement versus no replacement following pancreaticoduodenectomy. Two review authors independently extracted the data. The outcomes studied were incidence of pancreatic fistula, need for reoperation, length of hospital stay, overall complications, and in-hospital mortality. We showed the results as risk ratio (RR) or mean difference (MD), with 95% confidence interval (CI). We assessed the quality of evidence using GRADE (http://www.gradeworkinggroup.org/). We included eight studies (1018 participants). The average age of the participants ranged from 56 to 68 years. Most of the studies were conducted in single centers in Japan (four studies), China (two studies), France (one study), and the USA (one study). The risk of bias was low or unclear for most domains across the studies. Stents versus no stentsThe effect of stents on reducing pancreatic fistula in people undergoing pancreaticoduodenectomy was uncertain due to the low quality of the evidence (RR 0.67, 95% CI 0.39 to 1.14; 605 participants; 4 studies). The risk of in-hospital mortality was 3% in people who did receive

  4. Stent deformation at the edge of a high pressure balloon.

    PubMed

    Kilic, Ismail Dogu; Foin, Nicolas; Konstantinidis, Nikolaos; Serdoz, Roberta; Caiazzo, Gianluca; Di Mario, Carlo

    2015-12-01

    Focal ultrashort balloons are essential tools for lesion preparation and final stent expansion. However, they may cause a major distortion of the adjacent segments. Here we report a case with a stent deformation emphasizing the importance of utilizing intravascular imaging techniques for optimal interventions.

  5. Stent coating: a new approach in interventional cardiology.

    PubMed

    Wieneke, Heinrich; Sawitowski, Thomas; Wnendt, Stephan; Fischer, Alfons; Dirsch, Olaf; Karoussos, Ira Ariadne; Erbel, Raimund

    2002-09-01

    Since its introduction in clinical cardiology, several studies have shown the superiority of coronary stent implantation as compared to conventional angioplasty. However, restenosis still remains a major drawback of this new technique. Basic research in animal models could identify stent-related factors like stent-material and stent-design as major determinants of intima proliferation. Since materials with good biocompatibility often have unsuitable mechanical properties and vice versa, the concept of stent coating has been developed to allow the combination of favorable characteristics from different materials. In general, passive coatings, which only serve as a barrier between the stainless steel and the tissue, and active coatings, which directly interfere with the process of intima proliferation have been identified. Currently there are several passive coatings commercially available with good results in animal models and preliminary reports from clinical studies. As any surface induces some kind of tissue reaction promoting restenosis, an active stent coating with antiproliferative drugs has been proposed. However, while animal studies revealed convincing results, preliminary clinical studies not only showed active stent coating effective in preventing restenosis, but also demonstrated the potential risks of this new approach. Although this technique may harbor some specific risks, with the introduction of stent coating a new chapter of interventional cardiology has been flipped open.

  6. Optical stent inspection of surface texture and coating thickness

    NASA Astrophysics Data System (ADS)

    Bermudez, Carlos; Laguarta, Ferran; Cadevall, Cristina; Matilla, Aitor; Ibañez, Sergi; Artigas, Roger

    2017-02-01

    Stent quality control is a critical process. Coronary stents have to be inspected 100% so no defective stent is implanted into a human body. We have developed a high numerical aperture optical stent inspection system able to acquire both 2D and 3D images. Combining a rotational stage, an area camera with line-scan capability and a triple illumination arrangement, unrolled sections of the outer, inner, and sidewalls surfaces are obtained with high resolution. During stent inspection, surface roughness and coating thickness uniformity is of high interest. Due to the non-planar shape of the surface of the stents, the thickness values of the coating need to be corrected with the 3D surface local slopes. A theoretical model and a simulation are proposed, and a measurement with white light interferometry is shown. Confocal and spectroscopic reflectometry showed to be limited in this application due to stent surface roughness. Due to the high numerical aperture of the optical system, only certain parts of the stent are in focus, which is a problem for defect detection, specifically on the sidewalls. In order to obtain fully focused 2D images, an extended depth of field algorithm has been implemented. A comparison between pixel variance and Laplacian filtering is shown. To recover the stack image, two different methods are proposed: maximum projection and weighted intensity. Finally, we also discuss the implementation of the processing algorithms in both the CPU and GPU, targeting real-time 2-Million pixel image acquisition at 50 frames per second.

  7. Endovascular retrieval of a prematurely deployed covered stent.

    PubMed

    Miley, Jefferson T; Rodriguez, Gustavo J; Tummala, Ramachandra P

    2015-06-28

    Several techniques have been reported to address different endovascular device failures. We report the case of a premature deployment of a covered balloon mounted stent during endovascular repair of a post-traumatic carotid-cavernous fistula (CCF). A 50-year-old male suffered a fall resulting in loss of consciousness and multiple facial fractures. Five weeks later, he developed decreased left visual acuity, proptosis, chemosis, limited eye movements and cranial/orbit bruit. Cerebral angiography demonstrated a direct left CCF and endovascular repair with a 5.0 mm × 19 mm covered stent was planned. Once in the lacerum segment, increased resistance was encountered and the stent was withdrawn resulting in premature deployment. A 3 mm × 9 mm balloon was advanced over an exchange length microwire and through the stent lumen. Once distal to the stent, the balloon was inflated and slowly pulled back in contact with the stent. All devices were successfully withdrawn as a unit. The use of a balloon to retrieve a prematurely deployed balloon mounted stent is a potential rescue option if leaving the stent in situ carries risks.

  8. Vessel healings after stenting with different polymers in STEMI patients

    PubMed Central

    Jin, Qin-Hua; Chen, Yun-Dai; Tian, Feng; Guo, Jun; Jing, Jing; Sun, Zhi-Jun

    2016-01-01

    Background Different stents implantation in ST-segment elevation myocardial infarction (STEMI) patients may influence the long term prognosis by affecting vessel healings after stenting. The aim of this study was to evaluate the vessel healings after implantation of drug eluting stents (DES) with biodegradable or durable polymer or of bare-metal stents (BMS) in patients with acute STEMI. Methods This study included 50 patients, who underwent follow up angiogram and optical coherence tomography (OCT) assessment about one year after percutaneous coronary intervention (PCI) for STEMI. According to the initial stents types, these patients were classified to durable (n = 19) or biodegradable polymer sirolimus-eluting stents (n = 15), or BMS (n = 16) groups. The conditions of stent struts coverage and malapposition were analyzed with OCT technique. Results A total of 9003 struts were analyzed: 3299, 3202 and 2502 from durable or biodegradable polymer DES, or BMS, respectively. Strut coverage rate (89.0%, 94.9% and 99.3%, respectively), malapposition presence (1.7%, 0.03% and 0 of struts, respectively) and average intimal thickness over struts (76 ± 12 µm, 161 ± 30 µm and 292 ± 29 µm, respectively) were significantly different among different stent groups (all P < 0.001). Conclusions Vessel healing status in STEMI patients is superior after implantation of biodegradable polymer DES than durable polymer DES, while both are inferior to BMS. PMID:27403139

  9. Stenting in the Treatment of Acute Ischemic Stroke: Literature Review

    PubMed Central

    Samaniego, Edgar A.; Dabus, Guilherme; Linfante, Italo

    2011-01-01

    Recanalization of acute large artery occlusions is a strong predictor of good outcome. The development of thrombectomy devices resulted in a significant improvement in recanalization rates compared to thrombolytics alone. However, clinical trials and registries with these thrombectomy devices in acute ischemic stroke (AIS) have shown recanalization rates in the range of 40–81%. The last decade has seen the development of nickel titanium self-expandable stents (SES). These stents, in contrast to balloon-mounted stents, allow better navigability and deployment in tortuous vessels and therefore are optimal for the cerebral circulation. SES were initially used for stent-assisted coil embolization of intracranial aneurysms and for treatment of intracranial stenosis. However, a few authors have recently reported feasibility of deployment of SES in AIS. The use of these devices yielded higher recanalization rates compared to traditional thrombectomy devices. Encouraged by these results, retrievable SES systems have been recently used in AIS. These devices offer the advantage of resheathing and retrieving of the stent even after full deployment. Some of these stents can also be detached in case permanent stent placement is needed. Retrievable SES are being used in Europe and currently tested in clinical trials in the United States. We review the recent literature in the use of stents for the treatment of AIS secondary to large vessel occlusion. PMID:22163225

  10. Adult Patent Ductus Arteriosus: Treatment with a Stent-Graft

    SciTech Connect

    Munoz, J.J. Urbaneja, A.; Gonzalez, N.; Martinez, J.L.

    2008-03-15

    We present the case of a 63-year-old woman with a short patent ductus arteriosus and aneurysmal pulmonary arteries who was treated by placement of a stent-graft. The technique proved simple and safe. Further research is required to improve the design of stent-grafts and their release system for use of this technique in adult patients with this disorder.

  11. Partially Polyurethane-Covered Stent for Cerebral Aneurysm Treatment

    PubMed Central

    Rangwala, Hussain S.; Ionita, Ciprian N.; Rudin, Stephen; Baier, Robert E.

    2009-01-01

    Partially polyurethane-covered stent (PPCS) is proposed for the treatment of cerebral aneurysms. The PPCSs were observed to substantially modify the flow entering the aneurysm in a patient-specific aneurysm phantom (PSAP). These stents can act as flow modulators and the polyurethane (PU) membrane can provide a smooth scaffold for restoring the structural integrity of the diseased vessel. Partial coating of the stent aids in sealing only the entrance to the aneurysm while keeping the perforators around the aneurysm open and patent. Biocompatibility of the PU membrane was monitored using contact angle measurements to show that critical surface tension (CST) values remained in the thromboresistant range of 20–30 mN/m. Stent flexibility, stiffness, and pressure–diameter relationship showed no significant change after asymmetric PU film application. No delamination of the PU membrane from the stent was observed within the working strains of the stent. The flow modulating capability of the PPCS was monitored by intentionally orienting the stent to cover either the proximal or the distal regions along the neck of the PSAP. Time density curves (TDCs) compared the relative metrics of input rate, washout rate, residence time, and influx in the aneurysm before and after the stent placement. PMID:18837459

  12. Polymeric photosensitizer-embedded self-expanding metal stent for repeatable endoscopic photodynamic therapy of cholangiocarcinoma.

    PubMed

    Bae, Byoung-chan; Yang, Su-Geun; Jeong, Seok; Lee, Don Haeng; Na, Kun; Kim, Joon Mee; Costamagna, Guido; Kozarek, Richard A; Isayama, Hiroyuki; Deviere, Jacques; Seo, Dong Wan; Nageshwar Reddy, D

    2014-10-01

    Photodynamic therapy (PDT) is a new therapeutic approach for the palliative treatment of malignant bile duct obstruction. In this study, we designed photosensitizer-embedded self-expanding nonvascular metal stent (PDT-stent) which allows repeatable photodynamic treatment of cholangiocarcinoma without systemic injection of photosensitizer. Polymeric photosensitizer (pullulan acetate-conjugated pheophorbide A; PPA) was incorporated in self-expanding nonvascular metal stent. Residence of PPA in the stent was estimated in buffer solution and subcutaneous implantation on mouse. Photodynamic activity of PDT-stent was evaluated through laserexposure on stent-layered tumor cell lines, HCT-116 tumor-xenograft mouse models and endoscopic intervention of PDT-stent on bile duct of mini pigs. Photo-fluorescence imaging of the PDT-stent demonstrated homogeneous embedding of polymeric Pheo-A (PPA) on stent membrane. PDT-stent sustained its photodynamic activities at least for 2 month. And which implies repeatable endoscopic PDT is possible after stent emplacement. The PDT-stent after light exposure successfully generated cytotoxic singlet oxygen in the surrounding tissues, inducing apoptotic degradation of tumor cells and regression of xenograft tumors on mouse models. Endoscopic biliary in-stent photodynamic treatments on minipigs also suggested the potential efficacy of PDT-stent on cholangiocarcinoma. In vivo and in vitro studies revealed our PDT-stent, allows repeatable endoscopic biliary PDT, has the potential for the combination therapy (stent plus PDT) of cholangiocarcinoma. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. A novel biodegradable esophageal stent: results from mechanical and animal experiments

    PubMed Central

    Liu, Jin; Shang, Liang; Liu, Jiyong; Qin, Chengyong

    2016-01-01

    Biodegradable esophageal stents eliminate stent retrieval, but usually induce hyperplasia. This study investigated the properties of a novel biodegradable stent in vitro and in vivo. The degradation of the novel stent was observed in phosphate buffered saline (PBS) for 8 weeks. The radial forces, pH values, morphology, and retention rate of the intrinsic viscosity (R[η]) of the new biodegradable stent were all evaluated. In vitro, the pH values remained constant for 4 weeks and declined from weeks 4 to 8. The biodegradable threads degraded and ruptured at 6 weeks. Consequently, the radial force of the stent decreased to zero at that time. The curve of R[η] decreased with time linearly in PBS. To study the stents in vivo, we used a stricture model in which the middle esophagus of rabbits was damaged by alkali burn. Stents were inserted 2 weeks after injury and observed for 8 weeks. We assessed complications related to stent insertion, degradation of the stent, and survival of the rabbits. Two stents migrated, and one rabbit died. In the other rabbits, two stents degraded and moved into the stomach during the sixth week, five during the seventh week and one during the eighth week, respectively. One stent remained in position until the end of the study. In conclusion, our newly designed stent retained the strong radial force of self-expandable metal stents (SEMSs) and maintained the biodegradable properties of biodegradable (BD) stents. PMID:27158397

  14. A novel biodegradable esophageal stent: results from mechanical and animal experiments.

    PubMed

    Liu, Jin; Shang, Liang; Liu, Jiyong; Qin, Chengyong

    2016-01-01

    Biodegradable esophageal stents eliminate stent retrieval, but usually induce hyperplasia. This study investigated the properties of a novel biodegradable stent in vitro and in vivo. The degradation of the novel stent was observed in phosphate buffered saline (PBS) for 8 weeks. The radial forces, pH values, morphology, and retention rate of the intrinsic viscosity (R[η]) of the new biodegradable stent were all evaluated. In vitro, the pH values remained constant for 4 weeks and declined from weeks 4 to 8. The biodegradable threads degraded and ruptured at 6 weeks. Consequently, the radial force of the stent decreased to zero at that time. The curve of R[η] decreased with time linearly in PBS. To study the stents in vivo, we used a stricture model in which the middle esophagus of rabbits was damaged by alkali burn. Stents were inserted 2 weeks after injury and observed for 8 weeks. We assessed complications related to stent insertion, degradation of the stent, and survival of the rabbits. Two stents migrated, and one rabbit died. In the other rabbits, two stents degraded and moved into the stomach during the sixth week, five during the seventh week and one during the eighth week, respectively. One stent remained in position until the end of the study. In conclusion, our newly designed stent retained the strong radial force of self-expandable metal stents (SEMSs) and maintained the biodegradable properties of biodegradable (BD) stents.

  15. Successful Coronary Stent Retrieval from the Saphenous Vein Graft to Right Coronary Artery

    PubMed Central

    Aydin, Mustafa; Sayin, Muhammet Rasit

    2009-01-01

    Stent dislodgement and migration is a rare but serious complication of stent usage. For extraction of unexpanded stents different techniques have been described previously. We describe a case which used small baloon catheter for retrieval of a stent from the SVG-RCA. PMID:19902010

  16. Routine intraoperative ureteric stenting for kidney transplant recipients.

    PubMed

    Wilson, C H; Bhatti, A A; Rix, D A; Manas, D M

    2005-10-19

    Major urological complications (MUCs) after kidney transplantation contribute to patient morbidity and compromise graft function. The majority arise from the vesico-ureteric anastomosis and present early after transplantation. Ureteric stents have been successfully used to treat such complications. A number of centres have adopted a policy of universal prophylactic stenting, at the time of graft implantation, to reduce the incidence of urine leaks and ureteric stenosis. Stents are associated with specific complications and some centres advocate a policy of only stenting selected anastomoses. To examine the benefits and harms of routine ureteric stenting to prevent urological complications in kidney transplant recipients. We searched the Cochrane Central Register of Controlled Trials (CENTRAL in The Cochrane Library), MEDLINE, EMBASE, reference lists of articles, books and abstracts and contacted companies, authors and experts to identify relevant randomised controlled trials (RCTs). All RCTs and quasi-RCTs were included in our meta-analysis. Four reviewers assessed the trials for quality against four criteria (allocation concealment, blinding, intention-to-treat and completeness of follow-up). The primary outcome was the incidence of MUCs. Further outcomes of interest were graft and patient survival and the incidence of adverse events (urinary tract infection (UTI), haematuria, irritative symptoms, pain and stent migration). Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) with 95% confidence intervals (CI). Seven RCTs (1154 patients) of low or moderate quality were identified. The incidence of MUCs was significantly reduced (RR 0.24, 95% CI 0.07 to 0.77, P = 0.02, NNT 13) by universal prophylactic stenting. This was dependent on whether the same surgeon performed, or was in attendance, during the operations. Two patients lost their grafts to infective urinary tract complications in the stented group

  17. Endoscopic stenting of gastric staple line leak following sleeve gastrectomy.

    PubMed

    Slim, Rita; Smayra, Tarek; Chakhtoura, Ghassan; Noun, Roger

    2013-11-01

    Laparoscopic sleeve gastrectomy is known to be associated with a risk of gastric staple line leak. We report on our experience with endoscopic stenting of the anomalous leaking tract. Three cases of post sleeve gastric leak confirmed by computed tomography scan were treated by endoscopic stenting of their leak with a plastic endoprosthesis under fluoroscopic and endoscopic guidance. Endoscopic stenting by means of biliary or pancreatic endoprosthesis was successful in the three patients. The median number of endoscopy procedures per patient was 1.3. Stents were extracted 6 to 10 weeks after their placement. Neither morbidity nor recurrence was noticed on follow-up. Endoscopic stenting of gastric staple line leak following sleeve gastrectomy proved to be an efficacious technique for leak healing.

  18. Atrial septal stenting — How I do it?

    PubMed Central

    Sivakumar, Kothandam

    2015-01-01

    A wide atrial communication is important to maintain hemodynamics in certain forms of congenital and acquired heart defects. In comparison to balloon septostomy or blade septostomy, atrial septal stenting provides a controlled, predictable, and long-lasting atrial communication. It often needs a prior Brockenbrough needle septal puncture to obtain a stable stent position. A stent deployed across a previously dilated and stretched oval foramen or tunnel form of oval foramen carries higher risk of embolization. This review provides technical tips to achieve a safe atrial septal stenting. Even though this is a “How to do it article,” an initial discussion about the indications for atrial septal stenting is vital as the resultant size of the atrial septal communication should be tailored for each indication. PMID:25684885

  19. Late acute thrombosis after paclitaxel eluting stent implantation

    PubMed Central

    Liistro, F; Colombo, A

    2001-01-01

    Late (more than six months) total occlusion after coronary stenting is a progressive phenomenon occurring in approximately 4% of patients, leading to acute myocardial infarction in less than 0.5%. The process must be related to severe and progressive intimal hyperplasia. In patients receiving coronary stenting with simultaneous brachytherapy, late total occlusion has been reported at a higher rate and to be related to stent thrombosis rather than intimal hyperplasia. Late total occlusion presenting with an acute clinical event seven months after the implantation of a paclitaxel drug eluting stent is reported. The occlusion developed soon after the interruption of ticlopidine treatment, suggesting that the event had a thrombotic genesis and that the risk is not confined to the first six month period.


Keywords: paclitaxel eluting stent; late thrombosis PMID:11514475

  20. Undilatable Stent Neoatherosclerosis Treated with Ad Hoc Rotational Atherectomy

    PubMed Central

    Koutouzis, Michael; Maniotis, Christos; Tsiafoutis, Ioannis; Argyriou, Mihalis

    2017-01-01

    A middle age woman with known ischemic heart disease and old stents in proximal left anterior descending coronary artery (LAD) was admitted to Coronary Care Unit with acute coronary syndrome. The coronary angiography showed one vessel disease with significant restenosis within the previously implanted stents. The lesion was tough and remained undilatable despite high pressure balloon inflation. Eventually, the balloon ruptured creating a massive dissection of the LAD beginning immediately after the distal part of the undilatable lesion. We proceeded with a challenging ad hoc rotational atherectomy of the lesion and finally stenting of the lesion. In-stent restenosis many years after stent implantation is considered to be mainly due to neoatheromatosis compared to intimal hyperplasia, making lesion treatment more difficult and unpredictable. PMID:28168062

  1. Treatment of Carotid Siphon Aneurysms with a Microcell Stent

    PubMed Central

    Leonardi, M.; Dall’Olio, M.; Princiotta, C.; Simonetti, L.

    2008-01-01

    Summary The treatment of giant, large, multiple or wide-necked carotid siphon aneurysms has always represented a challenge for neurosurgeons and neuroradiologists. Very recently the use of stents with tiny holes has been proposed by two companies: Balt Silk Stent in Europe and Pi-peline in America. We have used the Silk stent on a few patients and describe our first case who now has an eleven month follow-up. The carotid siphon presented three converging aneurysms sharing a very large common neck. The Silk stent (Balt Extrusion, Montmorency, France) was deployed through a 4F Balt introducer. The procedure was uneventful and very quick. As soon as the stent was positioned contrast medium stagnation was displayed within the aneur-ysm. The patient’s post-operative course was normal and she was discharged three days later in good health. PMID:20557742

  2. Stenting of the Lower Gastrointestinal Tract: Current Status

    SciTech Connect

    Katsanos, Konstantinos; Sabharwal, Tarun Adam, Andreas

    2011-06-15

    Colon obstruction due to colorectal cancer is a major surgical emergency. Patients with acute bowel obstruction are usually poor surgical candidates with 10-20% operative mortality and 40-50% operative morbidity rates. Colorectal stenting is an image-guided, minimally invasive procedure, and typical indications include either palliation of inoperable malignant disease or temporary bowel decompression as a bridge to surgery. Colorectal stenting allows the patient to recover before definite elective surgical resection, reducing perioperative morbidity and mortality, overall hospital stay, and associated health care costs. Palliative stenting improves quality of life compared to surgery. A concise review is provided of contemporary stenting practice of the lower gastrointestinal tract, the colon in particular, and both palliative and preoperative adjuvant procedures are evaluated in terms of relevant patient oncology, insertion technique, available stent designs, technical and clinical outcomes, associated complications, and cost-benefit analysis.

  3. Magnesium Alloys for Bioabsorbable Stents: A Feasibility Assessment

    NASA Astrophysics Data System (ADS)

    Deng, Charles Z.; Radhakrishnan, Rajesh; Larsen, Steve R.; Boismer, Dennis A.; Stinson, Jon S.; Hotchkiss, Adrienne K.; Petersen, Eric M.; Weber, Jan; Scheuermann, Torsten

    Today, stent designs consist of permanent metal alloy scaffolds which hold arteries open after percutaneous coronary intervention (PCI) to maintain arterial blood flow. Bioabsorbable stents are being investigated as an alternate for permanent stents, that disintegrate and dissolve in the body. In this article, we profile magnesium (Mg) alloy as a candidate for bioabsorbable stent material, and discuss aspects of its properties and challenges. Experimental data are generated in effort to draw correlations between in vivo vessel absorption and in vitro degradation, and to provide an overview of alloy mechanical properties, stent designs, and electrochemical behaviors. Preclinical porcine coronary model test results exhibit early on-set and rapid corrosion presenting a challenge to researchers to establish material design concepts that balance degradation time, duration for need of scaffolding, and healing.

  4. Drug-eluting stents: some first-generation problems.

    PubMed

    Murphy, Bruce E

    2004-01-01

    The recent fervor surrounding the introduction of drug-eluting stents into the practice of cardiology has proven to be problematic. The experience with the Cypher Sirolimus-Eluting Coronary Stent (Cordis Corp., Miami Lakes, FL) at Arkansas Heart Hospital progressed from anxious anticipation to complete removal of the stent from inventory in a 6-month period. Several cases involving edge dissection and subacute thrombosis were the catalyst for the decision to cease use of the device. While new products may entice, each new modality must be approached with measured enthusiasm. Drug-eluting stents are first-generation devices that may have unexposed flaws when used as first-line treatment in routine practice. The first-generation Cypher stent, as with many new devices, offers treatment-not a cure-for coronary atherosclerosis and enhances the desire for an evolved product.

  5. Robot-Assisted Antegrade In-Situ Fenestrated Stent Grafting

    SciTech Connect

    Riga, Celia V. Bicknell, Colin D.; Wallace, Daniel; Hamady, Mohamad; Cheshire, Nicholas

    2009-05-15

    To determine the technical feasibility of a novel approach of in-situ fenestration of aortic stent grafts by using a remotely controlled robotic steerable catheter system in the porcine model. A 65-kg pig underwent robot-assisted bilateral antegrade in-situ renal fenestration of an abdominal aortic stent graft with subsequent successful deployment of a bare metal stent into the right renal artery. A 16-mm iliac extension covered stent served as the porcine aortic endograft. Under fluoroscopic guidance, the graft was punctured with a 20-G customized diathermy needle that was introduced and kept in place by the robotic arm. The needle was exchanged for a 4 x 20 mm cutting balloon before successful deployment of the renal stent. Robot-assisted antegrade in-situ fenestration is technically feasible in a large mammalian model. The robotic system enables precise manipulation, stable positioning, and minimum instrumentation of the aorta and its branches while minimizing radiation exposure.

  6. Stent Placement for Portal Vein Stenosis After Pancreaticoduodenectomy.

    PubMed

    Hiyoshi, Masahide; Fujii, Yoshiro; Kondo, Kazuhiro; Imamura, Naoya; Nagano, Motoaki; Ohuchida, Jiro

    2015-09-01

    Portal vein (PV) stenosis is a worrisome late complication following pancreaticoduodenectomy (PD) that causes intestinal bleeding from varices, which must be diagnosed correctly and treated promptly. Recent reports advocate the usefulness of stent placement to improve PV stenosis. We evaluated the cause, diagnosis, and treatment method of PV stenosis after PD and the duration of stent patency in our institution. Intestinal bleeding caused by PV stenosis occurred in 5 (2.4%) of 205 patients. A computed tomography scan was useful to diagnose this complication. Four of 5 patients with PV stenosis underwent percutaneous transhepatic PV stent placement. The duration of stent patency was 21-41 months, and no rebleeding occurred. Percutaneous stent placement is viable, less invasive option than laparotomy for the management of PV stenosis after PD.

  7. An Indwelling Ureteral Stent Forgotten for Over 12 Years

    PubMed Central

    Bidnur, Samir; Huynh, Melissa; Hoag, Nathan

    2016-01-01

    Abstract Ureteral stents are one of the most commonly used urologic devices with the purpose of establishing and maintaining ureteral patency. They are also associated with a number of complications including infection, migration, stent-related symptoms, and encrustation, leading to lithiasis. Prolonged stent dwell time is associated with a greater degree of these complications. We present the case of a 36-year-old man who presented with a severely encrusted ureteral stent that had been placed 12.5 years prior for an obstructive left-sided ureteral stone and was lost to follow-up. The patient underwent a combination of percutaneous nephrolithomy, cystolitholapaxy, and ureteroscopy to remove the stent and associated 1.7 cm renal pelvic stone and 4.1 cm bladder stone, necessitating two operative sittings to render him stone free. PMID:27579442

  8. Intravascular brachytherapy with radioactive stents produced by ion implantation

    NASA Astrophysics Data System (ADS)

    Golombeck, M.-A.; Heise, S.; Schloesser, K.; Schuessler, B.; Schweickert, H.

    2003-05-01

    About 1 million patients are treated for stenosis of coronary arteries by percutaneous balloon angioplasty annually worldwide. In many cases a so called stent is inserted into the vessel to keep it mechanically open. Restenosis is observed in about 20-30% of these cases, which can be treated by irradiating the stented vessel segment. In our approach, we utilized the stent itself as radiation source by ion implanting 32P. Investigations of the surface properties were performed with special emphasis on activity retention. Clinical data of about 400 patients showed radioactive stents can suppress instent restenosis, but a so called edge effect appeared, which can be avoided by the new "drug eluting stents".

  9. Arteriovenous fistula stent infection diagnosed with radiolabelled leucocyte scintigraphy.

    PubMed

    Yoo, Jeong Rae; Heo, Sang Taek; Kim, Miyeon; Kim, Hyun Woo; Chang, Jee Won; Song, Heesung

    2015-07-01

    Infectious complications of haemodialysis in patients with arteriovenous fistula stent are rare. In addition, patients with low-grade infection are more difficult to diagnose. Here, we report the first case of low-grade infection of an arteriovenous fistula stent diagnosed using (99m)Tc-hexamethylpropylene amine oxime (HMPAO)-labelled leucocyte scintigraphy. A 62-year-old man with end-stage renal disease was referred for prolonged fever. We performed (99m)Tc-HMPAO-labelled leucocyte scintigraphy following a work-up according to fever of unknown origin. A focal uptake on the left forearm compatible with the arteriovenous fistula stent insertion site was shown, and the stent was removed. (99m)Tc-HMPAO-labelled leucocyte scintigraphy could be a suitable method for assessing vascular stent infection in low-grade fever.

  10. Design and modeling balloon-expandable coronary stent for manufacturability

    NASA Astrophysics Data System (ADS)

    Suryawan, D.; Suyitno

    2017-02-01

    Coronary artery disease (CAD) is a disease that caused by narrowing of the coronary artery. The narrowing coronary artery is usually caused by cholesterol-containing deposit (plaque) which can cause a heart attack. CAD is the most common cause mortality in Indonesia. The commonly CAD treatment use the stent to opens or alleviate the narrowing coronary artery. In this study, the stent design is optimized for the manufacturability. Modeling is used to determine the free stent expansion due to applied pressure in the inner surface of the stent. The stress distribution, outer diameter change, and dogboning phenomena are investigated in the simulation. The result of modeling and simulating was analyzed and used to optimize the stent design before it is manufactured using EDM (Electric Discharge Machine) in the next research.

  11. Neoatherosclerosis after Drug-Eluting Stent Implantation: Roles and Mechanisms

    PubMed Central

    Cui, Yuanyuan; Shi, Dazhuo; Chen, Keji

    2016-01-01

    In-stent neoatherosclerosis (NA), characterized by a relatively thin fibrous cap and large volume of yellow-lipid accumulation after drug-eluting stents (DES) implantation, has attracted much attention owing to its close relationship with late complications, such as revascularization and late stent thrombosis (ST). Accumulating evidence has demonstrated that more than one-third of patients with first-generation DES present with NA. Even in the advent of second-generation DES, NA still occurs. It is indicated that endothelial dysfunction induced by DES plays a critical role in neoatherosclerotic development. Upregulation of reactive oxygen species (ROS) induced by DES implantation significantly affects endothelial cells healing and functioning, therefore rendering NA formation. In light of the role of ROS in suppression of endothelial healing, combining antioxidant therapies with stenting technology may facilitate reestablishing a functioning endothelium to improve clinical outcome for patients with stenting. PMID:27446509

  12. Drug-eluting stent in malignant biliary obstruction

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Ki; Jang, Sung Ill

    2012-10-01

    Endoscopic stent insertion is the treatment of choice for patients with malignant biliary obstruction. However, conventional stents enable only mechanical palliation of the obstruction, without any anti-tumor effects. Drugeluting stent (DES), which was first introduced in coronary artery disease, are currently under investigation for sustaining stent patency and prolonging patient survival by inhibiting tumor ingrowth in malignant biliary obstruction. Many factors affecting efficient drug delivery have been studied to determine how drugs with antitumor effects suppress tumor ingrowth, including the specific drugs incorporated, means of incorporating the drugs, mode of drug release, and stent structure. Advances have resulted in the construction of more effective non-vascular DES and ongoing clinical research. Non-vascular DES is expected to play a vital role in prolonging the survival of patients with malignant biliary obstruction.

  13. Endoscopic Stent Placement in the Palliation of Malignant Biliary Obstruction

    PubMed Central

    2011-01-01

    Biliary drainage with biliary stent placement is the treatment of choice for palliation in patients with malignant biliary obstruction caused by unresectable neoplasms. In such patients, the endoscopic approach can be initially used with percutaneous radiological intervention. In patients with unresectable malignant distal bile duct obstructions, endoscopic biliary drainage with biliary stent placement has now become the main and least invasive palliative modality, which has been proven to be more effective in >80% of cases with lower morbidity than surgery, and perhaps may provide a survival benefit. In patients with unresectable malignant hilar obstruction, the endoscopic approach for biliary drainage with biliary stent placement has also been considered as the treatment of choice. There is still a lack of clear consensus on the use of covered versus uncovered metal stents in malignant distal bile duct obstructions and plastic versus metal stents and unilateral versus bilateral drainage in malignant hilar obstructions. PMID:22741117

  14. Self-expanding nitinol stents: material and design considerations.

    PubMed

    Stoeckel, Dieter; Pelton, Alan; Duerig, Tom

    2004-02-01

    Nitinol (nickel-titanium) alloys exhibit a combination of properties which make these alloys particularly suited for self-expanding stents. Some of these properties cannot be found in engineering materials used for stents presently. This article explains the fundamental mechanism of shape memory and superelasticity, and how they relate to the characteristic performance of self-expanding stents. Nitinol stents are manufactured to a size slightly larger than the target vessel size and delivered constrained in a delivery system. After deployment, they position themselves against the vessel wall with a low, "chronic" outward force. They resist outside forces with a significantly higher radial resistive force. Despite the high nickel content of Nitinol, its corrosion resistance and biocompatibility is equal to that of other implant materials. The most common Nitinol stents are listed and described.

  15. [Problems with Ureteral Stents – a Never-Ending Story].

    PubMed

    Betschart, Patrick; Schmid, Hans-Peter; Abt, Dominik

    2016-03-16

    Temporary drainage of the upper urinary tract by internal ureteral stents is a common procedure to assure renal function and to treat pain caused by ureteral obstruction. Ureteral stents are frequently associated with side effects like urinary symptoms, pain or hematuria resulting in frequent medical consultations. In addition to good patient education, symptomatic drug therapy of stent-associated symptoms is often indicated and sufficient. However, complications like stent dysfunction or significant urinary tract infections have to be kept in mind, as they require further diagnostics and treatment. Therefore, especially general practitioners as a primary point of contact for the patients should be familiar with common ureteral stent-associated problems, their treatment and indications for patient referrals.

  16. Late coronary thrombosis in paclitaxel-eluting stents. Case reports.

    PubMed

    Cassin, Matteo; De Biasio, Marzia; Macor, Franco; Burelli, Claudio; Vendrametto, Fauzia; Driussi, Mauro; Nicolosi, Gian Luigi

    2007-04-01

    Drug-eluting stent (DES) implantation has reduced angiographic and clinical restenosis that actually develops in less than 10% of treated patients. DESs also tend to delay the endothelialisation process increasing the risk of stent thrombosis. Subacute stent thrombosis may complicate long-term success of coronary angioplasty; it is a sudden event and usually causes acute myocardial infarction or sudden cardiac death. Patients undergoing DES implantation should be treated with dual antiplatelet therapy for at least 3-6 months. We describe two cases presenting with ST-elevation acute myocardial infarction due to stent thrombosis that occurred late after deployment of a paclitaxel-eluting stent, after discontinuation of antiplatelet therapy. It is important, for clinical cardiologists and general practitioners, to know the potential risk of late thrombosis of DES patients and, consequently, the implications regarding management of antiplatelet therapy.

  17. Nanoporous CREG-Eluting Stent Attenuates In-Stent Neointimal Formation in Porcine Coronary Arteries

    PubMed Central

    Sun, Mingyu; Tao, Jie; Yan, Chenghui; Kang, Jian; Li, Shaohua

    2013-01-01

    Background The goal of this study was to evaluate the efficacy of a nanoporous CREG-eluting stent (CREGES) in inhibiting neointimal formation in a porcine coronary model. Methods In vitro proliferation assays were performed using isolated human endothelial and smooth muscle cells to investigate the cell-specific pharmacokinetic effects of CREG and sirolimus. We implanted CREGES, control sirolimus-eluting stents (SES) or bare metal stents (BMS) into pig coronary arteries. Histology and immunohistochemistry were performed to assess the efficacy of CREGES in inhibiting neointimal formation. Results CREG and sirolimus inhibited in vitro vascular smooth muscle cell proliferation to a similar degree. Interestingly, human endothelial cell proliferation was only significantly inhibited by sirolimus and was increased by CREG. CREGES attenuated neointimal formation after 4 weeks in porcine coronary model compared with BMS. No differences were found in the injury and inflammation scores among the groups. Scanning electron microscopy and CD31 staining by immunohistochemistry demonstrated an accelerated reendothelialization in the CREGES group com