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Endovascular treatment of peripheral arterial injury with covered stents: an experimental study in pigs
Belczak, Sergio;Silva, Erasmo Simi?o da;Aun, Ricardo;Sincos, Igor Rafael;Belon, Alessandro Rodrigo;Casella, Ivan Benaduce;Gornati, Vitor;Poli de Figueiredo, Luiz Francisco;
Clinics , 2011, DOI: 10.1590/S1807-59322011000800020
Abstract: objective: to evaluate the feasibility of using endovascular repair to treat penetrating arterial injuries with covered stents. feasibility was examined according to the circumferential extent of the injury. introduction: surgical trauma often increases the risk of major morbidity and mortality associated with vascular injury, and endovascular repair has many advantages in such situations. methods: twenty white male domestic pigs weighing 28-38 kg with controlled vascular injuries were divided into four equal groups according to the circumferential extent of their vascular lesion (i.e., no lesion, lesion <50%, lesion >50%, and complete lesion). the left common carotid artery was dissected with proximal and distal control, and this procedure was followed by controlled sectioning of the arterial wall. local manual compression was applied for 10 min and was followed by endovascular repair with the placement of a 5x50 mm viabhantm covered stent using the femoral approach. we also monitored additional variables, such as the duration of the procedures (the mean was 56.3 ± 19.1 min), ultrasound parameters (e.g., maximum arterial diameter, peak systolic and diastolic velocity, and resistance index), arteriography findings, and fluctuations in vital signs (e.g., cardiac output, arterial pressure, and central venous pressure). results: the experimental procedure was found to be feasible and reproducible. repairs were successful in all animals in the control (no lesion) and <50% lesion groups. success was also achieved in four out of five pigs in the >50% group and in one pig in the complete lesion group. discussion: the endovascular repair of an arterial injury is possible, but success depends on the circumferential extent of the arterial lesion. the present experimental model, which involved endovascular techniques, highlighted important factors that must be considered in future studies involving similar animals and materials.
Covered nitinol stents for the treatment of esophageal strictures and leaks  [cached]
Davide Bona, Letizia Laface, Luigi Bonavina, Emmanuele Abate, Moshe Schaffer, Ippazio Ugenti, Stefano Siboni, Rosaria Carrinola
World Journal of Gastroenterology , 2010,
Abstract: AIM: To compare 2 different types of covered esophageal nitinol stents (Ultraflex and Choostent) in terms of efficacy, complications, and long-term outcome.METHODS: A retrospective review of a consecutive series of 65 patients who underwent endoscopic placement of an Ultraflex stent (n = 33) or a Choostent (n = 32) from June 2001 to October 2009 was conducted.RESULTS: Stent placement was successful in all patients without hospital mortality. No significant differences in patient discomfort and complications were observed between the Ultraflex stent and Choostent groups. The median follow-up time was 6 mo (inter-quartile range 3-16 mo). Endoscopic reintervention was required in 9 patients (14%) because of stent migration or food obstruction. No significant difference in the rate of reintervention between the 2 groups was observed (P = 0.8). The mean dysphagia score 1 mo after stent placement was 1.9 ± 0.3 for the Ultraflex stent and 2.1 ± 0.4 for the Choostent (P = 0.6). At 1-mo follow-up endoscopy, the cover membrane of the stent appeared to be damaged more frequently in the Choostent group (P = 0.34). Removal of the Choostent was possible up to 8 wk without difficulty.CONCLUSION: Ultraflex and Choostent proved to be equally reliable for palliation of dysphagia and leaks. Removal of the Choostent was easy and safe under mild sedation.
Sealing of Airway Fistulas for Metallic Covered Z-type Stents  [cached]
Hongwu WANG,Dongmei LI,Nan ZHANG,Hang ZOU
Chinese Journal of Lung Cancer , 2011, DOI: 10.3779/j.issn.1009-3419.2011.08.08
Abstract: Background and objective Treating airway fistulas, including esophagorespiratory fistulas (ERFs), bronchopleural fistulas (BPFs), and tracheomediastinal fistulas (TMFs), is difficult. The aim of this study is to evaluate the safety and clinical efficacy of metallic covered Z-type stents (CZTS) for the treatment of airway fistulas through bronchoscopy or fluroscopy. Methods Thirty-eight patients with fistulas between the esophagus, mediastina, and airways (32 ERFs, 5 BPFs, and 1 TMF) were retrospectively reviewed after treatment with covered metallic esophageal and airway stents. The fistulas were caused by esophageal (n=26), bronchogenic (n=11), and thyroid (n=1) carcinomas. Results Forty-six fistulas were found in 38 patients. The fistula size ranged from 0.5 cm to 7.0 cm. Forty airway covered metal stents (24 Y-type, 8 L-type, and 8 I-type) and 24 esophageal metal stents were placed. Complete responses to the sealing effects of fistulas were noted in 4.3% of all the fistulas, 60.9% showed complete clinical responses, 23.9% showed partial responses, and 10.9% showed no response. An effectivity rate of 89.1% was observed, and the median survival duration of all patients was 5 months. Conclusion The use of CZTS appears to be safe and feasible for the palliative treatment of ERFs, BPFs, and TMFs. Airway stent placement is recommended for patients with ERF. In the event that airway stents fail, esophageal stents should be given. Airway bifurcation stents were observed to be especially suitable for the sealing of fistulas near the trachea carina.
Efeitos a curto prazo de "stents" n?o recobertos e recobertos com politetrafluoroetileno em aorta de suínos: um modelo experimental
Grüdtner, Marco Aurélio;Pereira, Adamastor Humberto;Costa, Luiz Francisco Machado da;Souza, Gilberto Gon?alves de;Argenta, Rodrigo;Longhi, Joel Alex;
Acta Cirurgica Brasileira , 2004, DOI: 10.1590/S0102-86502004000200008
Abstract: purpose: to report an experimental study evaluating, through digital morphometry, the intimal thickening of the arterial wall after the implant of auto-expandable stainless steel stents covered or not with polytetrafluoroethylene (ptfe) in the pig aorta. methods: in three groups of pigs a 12 f sheath was inserted in distal abdominal aorta. group i animals (n=5) served as control. group ii animals (n=10) received an auto-expandable uncovered metallic stent. on group iii animals (n=10) an auto-expandable stent covered with ptfe was inserted. after four weeks the animals were killed, the specimens were harvested and the intimal thickening was quantified by morphometric analysis. results: in the comparison among groups i, ii and iii referring to intimal, medial area and intimal index, it was not observed statistically significant variation. differences were identified among groups referring to luminal proximal (p=0,036) and distal areas (p=0,044). through multiple comparison tests for kruskal-wallis it was identified a difference between groups i and ii. however, when these variables were controlled by weigh factor (luminal area/weigh relation), this difference was not observed anymore. conclusion: in this short term study, the ptfe covering is not associated to further intimal thickening besides that promoted by the metallic mesh in large arteries and in high flow conditions.
Fully covered self-expandable metal stents for treatment of malignant and benign biliary strictures  [cached]
Ahmed Abdel Samie,Stephan Dette,Ulrich V?hringer,Michael Stumpf
World Journal of Gastrointestinal Endoscopy , 2012, DOI: 10.4253/wjge.v4.i9.405
Abstract: AIM: To present a series of covered self-expandable metal stents (CSEMS) placed for different indications and to evaluate the effectiveness, complications and extractability of these devices. METHODS: We therefore retrospectively reviewed the courses of patients who received CSEMS due to malignant as well as benign biliary strictures and post-sphincterotomy bleeding in our endoscopic unit between January 2010 and October 2011. RESULTS: Twenty-six patients received 28 stents due to different indications (20 stents due to malignant biliary strictures, six stents due to benign biliary strictures and two stents due to post-sphincterotomy bleeding). Biliary obstruction was relieved in all cases, regardless of the underlying cause. Hemostasis could be achieved in the two patients who received the stents for this purpose. Complications occurred in five patients (18%). Two patients (7%) developed cholecystitis, stents dislocated/migrated in other two patients (7%), and in one patient (3.6%) stent occlusion was documented during the study period. Seven stents were extracted endoscopically. Removal of stents was easily possible in all cases in which it was desired using standard forceps. Twelve patients underwent surgery with pylorus preserving duodenopancreatectomy. In all patients stents could be removed during the operation without difficulties. CONCLUSION: Despite the higher costs of these devices, fully covered self-expanding metal stents may be suitable to relief biliary obstruction due to bile duct stenosis, regardless of the underlying cause. CSEMS may also represent an effective treatment strategy of severe post-sphincterotomy bleeding, not controlled by other measures.
Fully Covered Self-Expandable Metal Stents for Treatment of Both Benign and Malignant Biliary Disorders  [PDF]
Ahmed Abdel Samie,Lorenz Theilmann
Diagnostic and Therapeutic Endoscopy , 2012, DOI: 10.1155/2012/498617
Abstract: Transpapillary stents are increasingly being used for biliary strictures, whether benign or malignant. However, there are different stent types and available data is controversial. Recently, completely covered self-expandable metal stents (CSEMSs) have been proposed as an alternative therapeutic option in different biliary indications, including strictures of the distal bile duct, anastomotic stenosis after orthotopic liver transplantation, bile duct leaks, periampullary perforation following endoscopic sphincterotomy (ES), and postsphincterotomy bleeding. Despite the higher costs of these devices, fully covered self-expanding metal stents seem to be a suitable therapeutic option to relief biliary obstruction due to bile duct stenosis, regardless of the underlying cause. 1. Introduction A multicenter trial comparing preoperative biliary drainage to early surgery for cancer of the pancreatic head showed that routine preoperative biliary drainage increased the rate of complications significantly [1]. The authors concluded that it should not be used routinely. Although drainage was primarily successful in 94%, there was a significant rate of cholangitis and a rate of 30% for the need of stent exchange leading to more readmissions. In addition, surgeons often report that they feel that anastomosis of the remaining biliary tract to the jejunal loop is more difficult and hampered because of the local inflammation caused by the stent. Nevertheless, in the trial above, plastic stents have been used. These stents have a narrow diameter which results in a high rate of stent occlusion over time with consequent cholangitis. This problem can partially be overcome using wide-bore stents such as self-expanding metal stents [2]. The disadvantage of these devices, however, is that once positioned they cannot be removed effortlessly without major damage to the biliary duct. Recently, completely covered self-expanding metal stents (CSEMSs) have become available making removal either endoscopically or during surgery easily possible. Accordingly, fully covered self-expandable metal stents have been lately used for the management of various malignant as well as benign biliary disorders, including strictures of the distal bile duct, anastomotic stenosis after orthotopic liver transplantation, and postsphincterotomy bleeding. Recent data demonstrated that biliary drainage can be achieved using fully covered self-expanding metal stents regardless of the underlying disease, be it benign or malignant. These stents were not associated with a higher rate of complication compared to
Use of fully covered self-expanding metal stents for the management of benign biliary conditions
García-Cano,J.; Taberna Arana,L.; Jimeno Ayllón,C.; Martínez Fernández,R.; Serrano Sánchez,L.; Reyes Guevara,A. K.; Vi?uelas Chicano,M.; Gómez Ruiz,C. J.; Morillas Ari?o,M. J.; Pérez García,J. I.; Pérez Vigara,G.; Pérez Sola,A.;
Revista Espa?ola de Enfermedades Digestivas , 2010, DOI: 10.4321/S1130-01082010000900003
Abstract: background and aim: biliary self-expanding metal stents (sems) have the advantage of being inserted undeployed with very small sizes and provide, when fully opened, large diameters for biliary drainage. however, their use in benign conditions has been very limited, mainly because of difficulty in their extraction. we present our initial experience with a fully covered sems (wallflex) for the management of benign problems of the bile duct. patients and methods: in a prospective study, stents of 8 mm in diameter and 4, 6 or 8 cm long were inserted by means of ercp. these sems were chosen when according to medical judgement it was thought that diameters greater than 10 french (3.3 mm) were needed for proper biliary drainage. stents were extracted also endoscopically, several months later when deemed clinically appropriate. results: twenty biliary sems were inserted. reasons for insertion were: large intrahepatic biliary fistula after hydatid cyst surgery (1), perforation of the papillary area following endoscopic sphincterotomy (2), coaxial insertion to achieve patency in obstructed uncovered stents inserted in benign conditions (3), benign strictures (7), multiple and large common bile duct stones that could not be extracted because of tapering and stricturing of the distal common bile duct (7). in all cases, successful biliary drainage was achieved and there were no complications from insertion. stents were easily extracted after a mean time of 132 days (36-270) in place. complete resolution of biliary problems was obtained in 14 patients (70%). conclusions: in our initial experience, the fully covered wallflex biliary stent was removed without any complication after being in place in the common bile duct for a mean time of over four months. therefore, it could be used in the management of benign biliary conditions.
Use of fully covered self-expanding metal stents in benign biliary diseases  [cached]
Jesús García-Cano
World Journal of Gastrointestinal Endoscopy , 2012, DOI: 10.4253/wjge.v4.i4.142
Abstract: Biliary fully covered self-expanding metal stents (FCSEMS) are now being used to treat several benign biliary conditions. Advantages include small predeployment and large postexpansion diameters in addition to an easy insertion technique. Lack of imbedding of the metal into the bile duct wall enables removability. In benign biliary strictures that usually require multiple procedures, despite the substantially higher cost of FCSEMS compared with plastic stents, the use of FCSEMS is offset by the reduced number of endoscopic retrograde cholangiopancreatography interventions required to achieve stricture resolution. In the same way, FCSEMS have also been employed to treat complex bile leaks, perforation and bleeding after endoscopic biliary sphincterotomy and as an aid to maintain permanent drainage tracts obtained by means of Endoscopic Ultrasound-guided biliary drainage. Good success rates have been achieved in all these conditions with an acceptable number of complications. FCSEMS were successfully removed in all patients. Comparative studies of FCSEMS and plastic stents are needed to demonstrate efficacy and cost-effectiveness
Fully covered self-expandable metal stents (SEMS), partially covered SEMS and self-expandable plastic stents for the treatment of benign esophageal ruptures and anastomotic leaks
Petra GA van Boeckel, Kulwinder S Dua, Bas LAM Weusten, Ruben JH Schmits, Naveen Surapaneni, Robin Timmer, Frank P Vleggaar, Peter D Siersema
BMC Gastroenterology , 2012, DOI: 10.1186/1471-230x-12-19
Abstract: Consecutive patients who underwent placement of a fully covered self-expandable metal stent (FSEMS), a partially covered SEMS (PSEMS) or a self-expanding plastic stent (SEPS) for a benign esophageal rupture or anastomotic leak after upper gastrointestinal surgery in the period 2007-2010 were included. Data on patient demographics, type of lesion, stent placement and removal, clinical success and complications were collectedA total of 52 patients received 83 esophageal stents (61 PSEMS, 15 FSEMS, 7 SEPS) for an anastomotic leak (n = 32), iatrogenic rupture (n = 13), Boerhaave's syndrome (n = 4) or other cause (n = 3). Endoscopic stent removal was successful in all but eight patients treated with a PSEMS due to tissue ingrowth. Clinical success was achieved in 34 (76%, intention-to-treat: 65%) patients (PSEMS: 73%, FSEMS: 83%, SEPS: 83%) after a median of 1 (range 1-5) stent and a median stenting time of 39 (range 7-120) days. In total, 33 complications in 24 (46%) patients occurred (tissue in- or overgrowth (n = 8), stent migration (n = 10), ruptured stent cover (all Ultraflex; n = 6), food obstruction (n = 3), severe pain (n = 2), esophageal rupture (n = 2), hemorrhage (n = 2)). One (2%) patient died of a stent-related cause.Covered stents placed for a period of 5-6 weeks may well be an alternative to surgery for treating benign esophageal ruptures or anastomotic leaks. As efficacy between PSEMS, FSEMS and SEPS is not different, stent choice should depend on expected risks of stent migration (SEPS and FSEMS) and tissue in- or overgrowth (PSEMS).Esophageal ruptures and anastomotic leaks are life-threatening injuries with a high mortality rate [1-7]. Most ruptures occur after (endoscopic) instrumentation or surgery, i.e. leaking anastomosis, but may also occur spontaneously after vomiting (Boerhaave's syndrome) [8]. Surgical repair including surgical closure or cervical exclusion or esophagectomy has long been considered to be 'gold standard' [4,8-12]. Although surger
Modulating the Release Kinetics of Paclitaxel from Membrane-Covered Stents Using Different Loading Strategies  [PDF]
Georg Sydow-Plum,Ziyad S. Haidar,Yahye Merhi,Maryam Tabrizian
Materials , 2008, DOI: 10.3390/ma1010025
Abstract: Membrane-covered Express2TM Monorail? stents composed of chitosan (CH) blended with polyethylene oxide (PEO) in 70:30% wt (CH-PEO) were coated with a monolayer of hyaluronic acid (HA). This significantly improved the resistance to platelet adhesion and demonstrated excellent mechanical properties, resisting the harsh conditions during stent crimping and subsequent inflation. CH-PEO/HA membrane was then combined with a paclitaxel (Pac) delivery system via three different approaches for comparison of release profiles of Pac. The activity of Pac in these systems was confirmed since its presence in the membrane significantly decreased cell viability of U937 macrophages. Presented results are promising for applications requiring different release patterns of hydrophobic drugs.
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