 - Inclusion criteria. Patients with liver cirrhosis of any etiology, diagnosed using imaging andor histological criteria and observed in the Liver Unit of the A. Gemelli University will be included in this study. All patients will sign an informed consent. The severity of liver function failure will be assessed using the Child-Pugh score 11. Upper gastrointestinal endoscopy will be performed in all patients; the size of esophageal varices will be recorded as well as the presence of previous episodes of gastrointestinal bleeding. All the subjects will be outpatients and the time interval between the follow up visits will be approximately 120 days. The ultrasound criteria for the diagnosis of PVT will be the detection of echogenic material within one or more of the following vessels: portal trunk, right portal branch, left portal branch, splenic vein and superior mesenteric vein. Color and pulsed Doppler analysis will allow to confirm the diagnosis and to distinguish partial from complete obstructive thrombosis and in all cases the Doppler ultrasound diagnosis of PVT will be confirmed by contrast enhanced abdomen computed tomography. The presence andor extension of the thrombosis to the other major vessels of the portal venous system mesenteric or splenic vein will registered in all patients. PVT will be classified according to the extension of thrombosis, as previously reported: grade I is referred to as portal thrombosis confined to the portal vein beyond the confluence of the splenic vein; grade II was a PVT extended to the superior mesenteric vein, but with patent mesenteric vessels; grade III is a PVT extended to the whole splanchnic venous system, but with large collaterals; grade IV is a thrombosis extended to the whole splanchnic venous system with only fine collaterals 12. All the biochemical and coagulation parameters described below, including ADAMTS-13 and VWF levels, will be measured at each follow up visit. 