Chronic Mesenteric Venous Thrombosis

The presentation of chronic mesenteric venous thrombosis is very different from that of the acute and subacute forms. The diagnosis is suggested by the presence of luminal thrombus and extensive venous collaterals or the inability to visualize the superior mesenteric vein on duplex ultrasonography or CT. Angiography can confirm the diagnosis but is rarely required. Though many patients present with nonspecific symptoms of several months’ duration, an increasing number of patients are identified through imaging studies obtained for unrelated reasons. These patients may have had no symptoms at the time of the thrombotic event; hence, the date of the event is usually unclear.

Patients with thrombosis involving the portal or splenic veins may have portal hypertension with esophagogastric varices, splenomegaly, and hypersplenism. Chronic mesenteric venous thrombosis should be differentiated from isolated splenic-vein thrombosis that is due to pancreatic neoplasm or pancreatitis; thrombosis in these conditions is related to a local effect on the splenic vein and not to any disorder of the thrombotic pathway. Patients with chronic mesenteric venous thrombosis often remain asymptomatic because there is extensive collateral venous drainage, but they may have gastrointestinal bleeding from gastroesophageal varices or varices at ectopic sites.

The treatment of chronic mesenteric venous thrombosis is symptomatic, with the aim of controlling variceal bleeding or preventing recurrent bleeding with the use of pharmacologic agents such as propranolol. Long-term anticoagulation is recommended in patients with underlying prothrombotic states. Endoscopic therapy is used both to control active bleeding and to prevent recurrent bleeding.24 The use of surgical portosystemic shunts is restricted to patients whose bleeding cannot be controlled by conservative measures and who have a suitable vein for anastomosis. When thrombosis is extensive and no suitable large vein is available, gastroesophageal devascularization or nonconventional shunts involving the anastomosis of a large venous collateral vein with a systemic vein may be considered.25