Anticoagulation Therapy After Splenectomy in Cirrhosis Patient

1\. Inclusion and Exclusion Criteria Inclusion criteria: Inpatients who received laparotomy or laparoscopic splenectomy according to clinical, B-ultrasound scan, CT or MRI diagnosis of cirrhosis and portal hypertension. Exclusion criteria: 1. ) Portal vein system thrombosis (PVST) found by preoperative color Doppler ultrasound or MRI examination; 2. ) Liver cirrhosis complicated with liver tumor; 3. ) Liver cirrhosis complicated with blood system diseases; 4. ) Patients who have not signed the informed consent form. 2\. Research subgroup According to the order of the patients, the following groups are entered in turn, and the cycle is repeated. 1. ) Heparin group 2. ) Rivaroxaban group 3. ) Control group.