The purpose of this study is to determine the effect and safety of anticoagulation after endoscopic therapy in cirrhotic patients with portal vein thrombosis and to explore its effect on long-term rebleeding rate and mortality.

The treatment of cirrhotic patients with PVT (portal vein thrombosis) is clearly recommended in guideline now. Several published studies has confirm the effect and safety of anticoagulation therapy in cirrhotic patients with PVT.The present studies are most observation studies with small sample size and low quality. The investigators need more high-quality research such as randomized controlled trials. This is a Zelen-designed multicenter randomized controlled trial. Patients will randomly enter into two groups:the anticoagulation group or the control group and then the investigator will make sure wether their are fond of the group and make decision by themselves. The recanalization rate and complications will be analyzed

Inclusion Criteria:

• Age between 18-70 years old;
• A clinical, radiological or histologic diagnosis of Liver cirrhosis and portal hypertension;
• Diagnosed of Portal vein thrombosis;
• Capable of understanding the purpose and risks of the study and informed consent to participate in the study;
• Have undergone endoscopy to prevent variceal rebleeding.

Exclusion Criteria:

• Age <18 or >70 years;
• Portal vein thrombosis diagnosed before 6 months;
• Patients with signs of acute PVT such as fever，abdominal pain or intestinal obstruction，who should be treated immediately;
• Pregnant or nursing;
• Hepatocellular carcinoma or other cancer;
• Severe cardiopulmonary diseases or concomitant renal insufficiency;
• cavernous transformation of the portal vein;
• Contradictions to endoscopy;
• Contradictions to anticoagulation,such as:allergy to LMWH or warfarin, severe uncontrolled hypertension, history of hemorrhagic cerebral vascular accident, recent peptic ulcer disease, bacterial endocarditis, ulcerative colitis，sustained platelet count < 50 x10^9/L);
• Taking immunosuppressive agent;
• Coagulation disorders other than the liver disease related;
• Variceal bleeding failed to control.