Transplant Trial Watch

Viscoelastic versus conventional coagulation tests to reduce blood product transfusion in patients undergoing liver transplantation: A systematic review and meta-analysis.

Aceto, P., et al.

European Journal of Anaesthesiology 2023; 40(1): 39-53.

This study aimed to compare the effectiveness of coagulation management guided by viscoelastic tests (VETs) versus conventional coagulation tests (CCTs) for reducing blood product transfusion in patients undergoing liver transplantation.

Databases including the Cochrane Central Library, Embase, PubMed/MEDLINE, and the Transfusion Evidence Library were searched. Study eligibility was determined by two independent reviewers. Data were extracted in duplicate. Risk of bias was assessed using the Newcastle–Ottawa scale for cohort studies and the Cochrane risk-of-bias tool for randomised controlled trials.

17 studies were included in the review.

The primary outcome of this study was the mean number of transfused units for each blood product, which included red blood cells (RBCs), platelets (PLTs), fresh frozen plasma, (FFP) and cryoprecipitate. The secondary outcomes included mortality rate, intensive care unit (ICU) and hospital length of stay (LOS).


CET Conclusions
Viscoelastic tests (VETs) have been shown to have superior diagnostic ability than conventional coagulation tests (CCT) such as INR and platelet count and have become widely adopted in the intra- and perioperative management of critically ill surgical patients. Whether that diagnostic superiority translates to more efficient administration of blood products in patients undergoing liver transplantation is less clear. This systematic review analysed data from observational and randomised controlled studies to answer this question. The authors suggest that there is overall a reduced rate of transfusion of red blood cells and fresh frozen plasma, and increased use of cryoprecipitate in the VET-guided group. Rates of platelet transfusion and secondary endpoints of mortality and length of hospital stay were not different between the VET and CCT groups. Only two of the 17 studies included in the meta-analysis were RCTs. Both of these failed to demonstrate a significant difference in outcomes but were of relatively small sample sizes. The observational data, although heterogenous and generally of low to moderate quality, did consistently report a benefit to VET-guided strategies. The authors also quoted good quality studies in other surgical groups (e.g. cardiac surgery). Taken together, these findings support the growing utilisation of VETs in patients undergoing liver transplantation, but the authors recommend larger RCTs to strengthen the evidence base and further clarify the effect on clinical outcomes.

Trial registration
PROSPERO - CRD42021230213

Funding source
Non-industry funded