Esophageal Stent for Refractory Variceal Bleeding: A Systemic Review and Meta-Analysis

Background. Preliminary studies suggest that covered self-expandable metal stents may be helpful in controlling esophageal variceal bleeding. Aims. To evaluate the effectiveness and safety of esophageal stent in refractory variceal bleeding in a systematic review and meta-analysis. Methods. A comprehensive literature search was conducted on PubMed, EMBASE, and Cochrane Library covering the period from January 1970 to December 2015. Data were selected and abstracted from eligible studies and were pooled using a random-effects model. Heterogeneity was assessed using 2 test. Results. Five studies involving 80 patients were included in the analysis. The age of patients ranged from 18 to 91 years. The mean duration of follow-up was 46.8 d (range, 30-60 d). The success rate of stent deployment was 96.7% (95% CI: 91.6%-99.5%) and complete response to esophageal stenting was in 93.9% (95% CI: 82.2%-99.6%). The incidence of rebleeding was 13.2% (95% CI: 1.8%-32.8%) and the overall mortality was 34.5% (95% CI: 24.8%-44.8%). Most of patients (87.4%) died from hepatic or multiple organ failure, and only 12.6% of patients died from uncontrolled bleeding. There was no stent-related complication reported and the incidence of stent migration was 21.6% (95% CI: 4.7%-46.1%). Conclusion. Esophageal stent may be considered in patients with variceal bleeding refractory to conventional therapy

Cyclic threshold shear strain for pore water pressure generation and stiffness degradation in marine clays at Yangtze estuary

Cyclic threshold shear strain is a fundamental property of saturated soils under cyclic loading. To investigate the cyclic threshold shear strain for pore water pressure generation (γtp) and stiffness degradation (γtd), a series of strain-controlled multistage undrained cyclic triaxial tests were carried out on in-situ saturated marine clay in the Yangtze estuary with different plasticity index Ip. The test results show that both γtp and γtd increase with increasing Ip, and γtp is larger than γtd for the same marine clay tested under the same conditions, with γtp = 0.017 ~ 0.019%, γtd = 0.008 ~ 0.012% for Ip of 17, γtp = 0.033 ~ 0.039%, γtd = 0.020 ~ 0.025% for Ip of 32, and γtp = 0.040 ~ 0.048%, γtd = 0.031 ~ 0.036% for Ip of 40. Moreover, the development of stiffness degradation may not necessarily require the generation of pore water pressure but can be aggravated by it. Furthermore, the γtp and γtd of marine clay are compared with terrestrial soils and marine clays cited from the published literature, the results indicate that the special marine sedimentary environment and the combined action of flow and tidal wave system cause the γtp and γtd of marine clay in the Yangtze estuary to be smaller than that of the terrestrial clays and marine clays in other sea areas