More than half of a group of cirrhosis patients with portal vein thrombosis achieved recanalization with anticoagulation treatment maintained for at least 12 months.
"Moreover, when complete recanalization is achieved, therapy with anticoagulants should be maintained throughout life in order to prevent recurrent thrombosis," wrote Dr. María Gabriela Delgado and Dr. Susana Seijo along with their colleagues in the July issue of Clinical Gastroenterology and Hepatology (doi: 10.1016/j.cgh.2012.01.012).
In the largest study to date to evaluate the safety and efficacy of anticoagulation for portal vein thrombosis in cirrhosis (for which there are no guidelines, according to the authors), the investigators looked at 55 patients with portal vein thrombosis and cirrhosis from four centers in Spain between June 2003 and September 2010.
All patients received anticoagulation according to the protocol of each hospital after the initiation of prophylaxis of variceal bleeding. For 31 patients, anticoagulation was indicated because of acute or subacute thrombosis, and in the remaining 24 patients, anticoagulation was started because of thrombosis progression.
Anticoagulant agents included low-molecular-weight heparin and vitamin K antagonists, wrote Dr. Delgado and Dr. Seijo, both of the University of Barcelona.
Over a mean 19 months of follow-up, half (n = 28) of the patients remained on anticoagulation until either the end of the study or liver transplant. The remaining 27 patients stopped treatment after a median of 6.3 months (range, 1-24 months).
A total of 33 patients achieved either complete or partial recanalization of the portal vein during the study period; 22 patients did not have a response.
There were three complete recanalizations that occurred within 1 month of anticoagulation initiation, and two patients achieved complete recanalization at month 12.
"Early initiation of anticoagulation therapy after the identification of thrombosis in an imaging study, especially in the first 2 weeks, was the only factor significantly associated with recanalization," wrote the authors.
A total of 17 patients had 30 clinical events during anticoagulation treatment. In 13 patients, these events were "liver related," according to the authors: six variceal bleeding episodes, eight new or worsening ascites cases, five hepatic encephalopathy cases, two spontaneous bacterial peritonitis cases, and two hepatocellular carcinoma cases (several patients had multiple events).
"Liver events were more frequent in patients not achieving recanalization (8/22) than in those achieving partial/complete recanalization (5/33)," added the investigators, though the difference between these groups did not reach significance (P = 0.1).
Non-liver-related events included five bleeding episodes, which the authors attributed to anticoagulation; one acute cholecystitis case; and one duodenal ulcer.
Overall, among the 11 total bleeding events (6 of which were liver related), the authors reported that all took place during the first year after starting anticoagulation, and five events occurred in the first 3 months of treatment.
Furthermore, the only significant predictor of bleeding was a platelet count below 50 × 109/L (P = .018).
Six patients died, none of whom were receiving anticoagulation at the time of death.
Despite its retrospective design and the fact that no comparison group was available, this study shows that "recanalization can be achieved very early after starting anticoagulation treatment; however, those patients who do not present early recanalization may finally achieve it when long-term anticoagulation therapy is maintained," wrote the authors.
More importantly, anticoagulation is "relatively safe" in this population, they added, except in cases of severely depressed platelet counts.
The authors disclosed no conflicts of interest related to this study, and indicated that the research was supported by public grants.