PURPOSE:Thromboembolism is a significant cause of morbidity and mortality in inflammatory bowel disease. Several prothrombotic conditions have been investigated in inflammatory bowel disease. The aim of this study was to evaluate the incidence of symptomatic postoperative superior mesenteric vein thrombosis in inflammatory bowel disease patients undergoing colonic resections and to identify and characterize their clinical presentation.METHODS:Between January 1999 and December 2001, 83 consecutive patients undergoing total colectomy for inflammatory bowel disease were studied retrospectively. Patients who developed new‐onset postoperative acute abdominal pain were evaluated by CT scan of the abdomen. A complete coagulation profile, including thrombin time, platelet count, protein C, protein S, antithrombin III, homocysteine level, factor V Leiden mutation, plasminogen, and prothrombin G20210A mutation, was obtained in patients diagnosed with superior mesenteric vein thrombosis.RESULTS:Four patients (4.8 percent; 3 females; 3 patients with ulcerative colitis and 1 with Crohn's colitis) developed symptomatic postoperative superior mesenteric vein thrombosis. Two of these patients had extension of the clot into the portal vein. Their presenting symptom was abdominal pain, with a median interval of ten days from the index surgery. The hematologic workup was negative in three patients, with one heterozygous for prothrombin G20210A mutation. All patients were treated with systemic anticoagulation for at least six months. One ulcerative colitis patient was diagnosed after abdominal colectomy and underwent an uneventful ileal pouch‐anal anastomosis after systemic anticoagulation.CONCLUSION:Postoperative superior mesenteric vein thrombosis is a more frequent occurrence than previously reported in patients with inflammatory bowel disease. Direct surgical trauma to the middle colic veins, with resulting thrombosis, is likely to be the precipitating factor in a borderline intrinsically hypercoagulable environment. All patients became asymptomatic after systemic anticoagulation and recovered uneventfully.