Anticoagulation for Nontumoral Portal Vein Thrombosis

The development of portal vein thrombosis (PVT) is explained by Virchows triad which includes genetic and acquired prothrombotic factors, a decrease in the velocity of blood flow and alteration in the endothelium of the portal vein. Acquired or genetic systemic thrombophilic factors are identified in nearly 60-70% of patients with noncirrhotic PVT and local factors in 30-40%. It is now clear that patients with cirrhosis, specially those with decompensated cirrhosis (Child-Pugh class B and C), have a prothrombotic tendency. Acute PVT usually presents with abdominal or lumbar pain of sudden onset but may be paucisymptomatic or an incidental finding in partial thrombosis, which is often the case in patients with cirrhosis. There is a trend for earlier recognition of PVT at an acute stage rather than the stage of cavernoma. In patients with chronic PVT, bleeding due to ruptured varices may be the presenting feature. The aim of anticoagulant therapy in acute PVT is to recanalize obstructed veins and prevent intestinal ischemia. Anticoagulation should be started as soon as possible in both patients with and without cirrhosis who develop nontumoral PVT. In patients with chronic PVT and those with underlying cirrhosis, upper gastrointestinal endoscopy prior to starting anticoagulation should always be performed to screen for large esophageal and/or gastric varices with high risk stigmata for bleeding and adequate prophylaxis of variceal bleeding started if indicated. Vitamin K antagonists and direct oral anticoagulants are both effective in noncirrhotic patients and those with compensated cirrhosis who develop nontumoral PVT. In patients with decompensated cirrhosis, low molecular weight heparin may be maintained with doses adjusted for thrombocytopenia and concomitant renal failure. Anticoagulation should not be stopped in patients with genetic or aquired thrombophilic conditions and those with concomitant superior mesenteric vein thrombosis. In patients with cirrhosis and notumoral PVT, anticoagulation should be preferably maintained in those on liver transplant list and should be considered also in those who tolerate anticoagulation without adverse events to avoid rethrombosis.