Background: Endoscopic sclerotherapy (ES) and band ligation are standard treatments for esophageal varices. Unfortunately, recurrence is common and seems to be related to esophageal collateral vessels, easily identifi...Background: Endoscopic sclerotherapy (ES) and band ligation are standard treatments for esophageal varices. Unfortunately, recurrence is common and seems to be related to esophageal collateral vessels, easily identified by EUS. Eradication of these vessels might lead to a more durable therapeutic effect. Objective: To compare ES with EUS-guided sclerotherapy of collateral vessels (EUS-ES). Design: Randomized controlled trial. Setting: Endoscopy Unit, Division of Gastroenterology. Universidade Federal de S o Paulo, S o Paulo, Brazil. Patients and Interventions: Fifty cirrhotic patientswith esophageal varices were randomized into 2 groups: ES (n = 25) and EUS-ES (n = 25). EUS-ES was targeted at collateral veins. Patients were followed-up for at least 6 months after eradication. Main Outcome Measurements: Efficacy in eradication, complications, and recurrence of varices. Results: Varices were eradicated in 48 patients who adhered to the study protocol. The mean (SD) number of sessions until eradication was 4.3 (1.5) for the ES group and 4.1 (1.2) for the EUS-ES group. In ES group, 4 patients had mild bleeding. In EUS-ES group, 4 patients had pain. The mean (SD) length of the follow-up period was 22.6 (6.9) months for the ES group and 24.9 (8.1) months for the EUS-ES group. Recurrence was seen in 4 patients after ES and in 2 after EUS-ES (P = .32). The presence of collateral vessels was associated with recurrence (P = .003). Conclusion: EUS-ES is as safe and effective as ES in variceal eradication. Recurrence tends to be less frequent and occurs later. Persistence of esophageal collateral vessels after sclerotherapy is a risk factor for recurrence.展开更多
This paper aims to find the relationship between the structural parameters and the radial stiffness of the braided stent and to understand the stress distribution law of the wires. According to the equation of the spa...This paper aims to find the relationship between the structural parameters and the radial stiffness of the braided stent and to understand the stress distribution law of the wires. According to the equation of the space spiral curve, a three-dimensional parametrical geometrical model is constructed. The finite element model is built by using the beam-beam contact elements and 3D beam elements. The constituent nitinol wires are assumed to be linear elastic material. The finite element analysis figures out that the radial stiffness of the stent and the stress distribution of the wires are influenced by all the structural parameters. The helix pitch of the wires is the most important factor. Under the condition of the same load and other structural parameters remaining unchanged, when the number of wires is 24, the stress of the wire crosssection is at the minimum. A comparison between the vitro experimental results and the analytical results is conducted, and the data is consistent, which proves that the current finite element model can be used to appropriately predict the mechanical performance of the braided esophageal stents.展开更多
文摘Background: Endoscopic sclerotherapy (ES) and band ligation are standard treatments for esophageal varices. Unfortunately, recurrence is common and seems to be related to esophageal collateral vessels, easily identified by EUS. Eradication of these vessels might lead to a more durable therapeutic effect. Objective: To compare ES with EUS-guided sclerotherapy of collateral vessels (EUS-ES). Design: Randomized controlled trial. Setting: Endoscopy Unit, Division of Gastroenterology. Universidade Federal de S o Paulo, S o Paulo, Brazil. Patients and Interventions: Fifty cirrhotic patientswith esophageal varices were randomized into 2 groups: ES (n = 25) and EUS-ES (n = 25). EUS-ES was targeted at collateral veins. Patients were followed-up for at least 6 months after eradication. Main Outcome Measurements: Efficacy in eradication, complications, and recurrence of varices. Results: Varices were eradicated in 48 patients who adhered to the study protocol. The mean (SD) number of sessions until eradication was 4.3 (1.5) for the ES group and 4.1 (1.2) for the EUS-ES group. In ES group, 4 patients had mild bleeding. In EUS-ES group, 4 patients had pain. The mean (SD) length of the follow-up period was 22.6 (6.9) months for the ES group and 24.9 (8.1) months for the EUS-ES group. Recurrence was seen in 4 patients after ES and in 2 after EUS-ES (P = .32). The presence of collateral vessels was associated with recurrence (P = .003). Conclusion: EUS-ES is as safe and effective as ES in variceal eradication. Recurrence tends to be less frequent and occurs later. Persistence of esophageal collateral vessels after sclerotherapy is a risk factor for recurrence.
基金The National Natural Science Foundation of China(No.51005124)the Opening Foundation of Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments(No.JS-NB-2009-1-1)
文摘This paper aims to find the relationship between the structural parameters and the radial stiffness of the braided stent and to understand the stress distribution law of the wires. According to the equation of the space spiral curve, a three-dimensional parametrical geometrical model is constructed. The finite element model is built by using the beam-beam contact elements and 3D beam elements. The constituent nitinol wires are assumed to be linear elastic material. The finite element analysis figures out that the radial stiffness of the stent and the stress distribution of the wires are influenced by all the structural parameters. The helix pitch of the wires is the most important factor. Under the condition of the same load and other structural parameters remaining unchanged, when the number of wires is 24, the stress of the wire crosssection is at the minimum. A comparison between the vitro experimental results and the analytical results is conducted, and the data is consistent, which proves that the current finite element model can be used to appropriately predict the mechanical performance of the braided esophageal stents.
