PubMed · 15520909
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A M Kassem. 2004. Gastrointestinal bleeding.. https://doi.org/10.1055/s-2004-825966
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Perhaps the greatest threat to the validity of a meta-analysis is the possibility of publication bias, where studies that are interesting or statistically significant are more likely to be published than those with less encouraging results. In particular, there is the concern that this bias might be 'one-sided', where studies indicating that the treatment is beneficial have a greater probability of publication. The impact that this type of bias has on the estimate of treatment effect has received a great deal of attention but this also has implications for estimates of between-study variance. Using step functions to model the bias it can be demonstrated that it is impossible to make generalizations concerning how we should revise estimates of between-study variance when presented with the possibility of publication bias. To determine this, assumptions must be made concerning the form that the bias takes, which is unknown in practice.
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BACKGROUND: Among the factors influencing variceal relapse after endoscopic treatment, portal hemodynamic changes, especially in portal systemic shunts, could be the most important factor because hemodynamics are directly related to the development of esophageal varices. We aimed to clarify the influence of endoscopic treatment for esophageal varices on portal systemic shunts as well as its predictive value for variceal relapse. METHODS: Fifty patients who underwent combined endoscopic variceal ligation and injection sclerotherapy were examined with sonography and portography. RESULTS: Decrease of diameter, hepatopetal flow direction in the left gastric vein, or the presence of non-varices portal systemic shunt were sonographic findings related to a low incidence of variceal relapse. The presence of blood flow in and around the esophagus on venograms was highly predictive for variceal relapse. In patients with such venograms, non-varices portal systemic shunts did not develop. CONCLUSIONS: Sonographic assessment of hemodynamic changes in portal systemic shunt could be useful for estimating the results of endoscopic treatment for esophageal varices.