The role of transjugular intrahepatic portosystemic shunt in the management of portal vein thrombosis: a systematic review and meta-analysis.

BACKGROUND: The role of transjugular intrahepatic portosystemic shunt (TIPS) in the management of portal vein thrombosis (PVT) remains controversial. This study aimed to conduct a systematic review and meta-analysis to evaluate the role of TIPS for the management of PVT in adult patients with liver disease. PATIENTS AND METHODS: Multiple databases were searched through April 2017. Data were gathered to estimate the rates of technical success, portal vein recanalization, portal patency, hepatic encephalopathy, and mean change in portal pressure gradient in patients with PVT who underwent TIPS. Estimates were pooled across studies using the random effects model. RESULTS: Eighteen studies were included in the analysis. The pooled technical success rate was 86.7% [95% confidence interval (CI)=78.6-92.1%]. Rate of portal vein recanalization was 84.4% (95% CI=78.4-89.0%). The rate of complete recanalization was 73.7% (95% CI=64.3-81.3%). Portal patency was 86.9% (95% CI=79.7-91.8%). Mean change in portal pressure gradient was 14.5 mmHg (95% CI=11.3-17.7 mmHg). Hepatic encephalopathy was 25.3% (95% CI=19.2-32.6%). The number of major adverse events reported across studies was low. The majority of the analyses were not associated with substantial heterogeneity. CONCLUSION: The use of TIPS in the management of PVT is feasible and effective in achieving a significant and sustainable reduction in clot burden with a low risk of major complications. TIPS should be considered as a viable treatment option in patients with PVT. Given the limited amount of randomized comparative studies reported, additional trials are warranted to assess the safety and efficacy of TIPS as a treatment modality in PVT, in comparison to other treatment options, such as anticoagulation.

Drinking in snakes: resolving a biomechanical puzzle.

Snakes have long been thought to drink with a two-phase buccal-pump mechanism, but observations that some snakes can drink without sealing the margins of their mouths suggest that buccal pumping may not be the only drinking mechanism used by snakes. Here, we report that some snakes appear to drink using sponge-like qualities of specific regions of the oropharyngeal and esophageal mucosa and sponge-compressing functions of certain muscles and bones of the head. The resulting mechanism allows them to transport water upward against the effects of gravity using movements much slower than those of many other vertebrates. To arrive at this model, drinking was examined in three snake species using synchronized ciné and electromyographic recordings of muscle activity and in a fourth species using synchronized video and pressure recordings. Functional data were correlated with a variety of anatomical features to test specific predictions of the buccal-pump model. The anatomical data suggest explanations for the lack of conformity between a buccal-pump model of drinking and the performance of the drinking apparatus in many species. Electromyographic data show that many muscles with major functions in feeding play minor roles in drinking and, conversely, some muscles with minor roles in feeding play major roles in drinking. Mouth sealing by either the tongue or mental scale, previously considered critical to drinking in snakes, is incidental to drinking performance in some species. The sponge mechanism of drinking may represent a macrostomatan exaptation of mucosal folds, the evolution of which was driven primarily by the demands of feeding.