Antithrombin III Administration for Portal Vein Thrombosis in Patients with Liver Disease: A Randomized Double-Blind Controlled Trial

Aim Portal vein thrombosis (PVT) is one of the most critical disorders in liver disease patients. These patients have the imbalance of coagulation and coagulation inhibition resulting from decreased levels of coagulation inhibitory factors, such as protein C, protein S, and antithrombin III (AT-III). We designed this randomized, double-blind, placebo-controlled trial comparing the safety and efficacy of AT-III administration for PVT in patients with those who received no treatment. Methods Eligible patients were diagnosed with the association of thrombus, without tumor thrombus, thrombus in more than 50% of the cross-sectional lumen of the portal vein. Patients with 70% or less serum level of AT-III were included. The study drug was administered up to 3 times in a 5-day consecutive infusion interval if the thrombus decreased in size. Efficacy was evaluated by contrast enhanced computed tomography using a five-grade scale (complete response, partial response, slight response, no response, and progression). From October 2014 through March 2016, 36 patients were randomly assigned to the AT-III group and 37 patients to the placebo group. Results The proportion of patients with complete response or partial response of PVT was significantly higher than that in the AT-III (55.6%; 20/36 patients, 95% confidence interval [CI] [38.1, 72.1]) than in the placebo (19.4%; 7/36, 95% CI [8.2, 36.0]) (P = .003). Overall incidences of adverse events and adverse drug reactions did not differ significantly between the two groups. Conclusion AT-III administration is one of the essential therapies for patients with PVT in cases with lower concentration levels of AT-III.