Veno-venous bypass versus none for liver transplantation.

Background: Veno-venous bypass is used to overcome the effects of clamping of the inferior vena cava and portal vein during liver transplanation. The routine use of veno-venous bypass is, however, controversial.

Objectives: To compare the benefits and harms of veno-venous bypass (irrespective of open or percutaneous technique; heparin-coated or no heparin-coating) versus no veno-venous bypass during liver transplantation. To compare the benefits and harms of the different techniques of veno-venous bypass during liver transplantation.

Search Strategy: We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until December 2010.

Selection Criteria: We included randomised clinical trials comparing veno-venous bypass during liver transplantation (irrespective of language or publication status).

Data Collection And Analysis: Two authors independently assessed trials for inclusion and independently extracted data. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For continuous outcomes, we calculated the mean difference (MD) with 95% confidence intervals (CI) based on intention-to-treat or available case analysis. For binary outcomes, we used the Fisher's exact test since none of the comparisons of binary outcomes included more than one trial.

Main Results: We identified three trials with high risk of bias which compared veno-venous bypass (n = 65) versus no veno-venous bypass (n = 66). None of the trials reported patient or graft survival. There were no significant differences regarding renal failure or blood transfusion requirements between the two groups. None of the trials reported on the morbidity related to veno-venous bypass or the requirement of veno-venous bypass in the control group.We identified one trial with high risk of bias which compared percutaneous (n = 20) versus open technique (n =19) of veno-venous bypass. The patient or graft survival was not reported. There was no difference in veno-venous bypass related morbidity between the two groups. The operating time was significantly shorter in the percutaneous technique group (MD -59 minutes; 95% CI -102 to -16).

Authors' Conclusions: There is no evidence to support or refute the use of veno-venous bypass in liver transplantation. There is no evidence to prefer any particular technique of veno-venous bypass in liver transplantation.