Treatment outcomes and risk factors for bowel infarction in patients with acute superior mesenteric venous thrombosis

Objective: The prognosis of acute superior mesenteric venous thrombosis (SMVT) remains obscure. We aimed to investigate the treatment outcomes and possible risk factors for bowel infarction in these patients. Methods: We retrospectively included 66 patients with acute SMVT between January 2002 and June 2016. Each patient underwent contrast-enhanced computed tomography as part of the initial diagnosis. The standard protocol for management included a nonsurgical approach with early anticoagulation and selective exploration. For the analysis of the risk factors for bowel infarction, patients were divided into bowel resection (BR) and non-BR groups. Outcomes of interest were causes of SMVT, percentage of BR after nonsurgical treatment, and risk factors for BR. Results: Of 66 patients, 15 (23%) underwent BR; of these, 9 underwent urgent BR because of peritoneal signs and definite findings of bowel infarction on computed tomography scan, 4 underwent BR after failed anticoagulation, and 2 underwent BR because of delayed stricture. Clinically, vomiting (P = .003), abdominal distention (P = .003), rebound tenderness (P = .005), and leukocytosis (P = .001) were associated with BR. On radiologic examination, bowel wall thickening (P < .001), enhancement defects of the bowel wall (P < .001), and ascites (P = .007) were associated with BR. Twenty-seven (41%) patients presented with isolated SMVT, and the remaining patients demonstrated a coexisting portal vein (PV) thrombosis in addition to SMVT. All 15 BRs occurred in patients with combined PV thrombosis and SMVT (P < .001). Complete thrombosis of the superior mesenteric vein and PV was also associated with BR (P = .028 for superior mesenteric vein; P = .025 for PV). BR was performed in 1 (4%) of 24 patients with transient risk factors compared with 14 (33%) of 42 patients without transient risk factors (P = .006). Three patients (4.5%) died in the hospital. Conclusions: In patients with acute SMVT, the extent of thrombus and etiology were associated with the severity of acute SMVT. Patients with transient risk factors and isolated SMVT tended to have a benign disease course. With early anticoagulation, acute SMVT does not seem to have the grave prognosis that is associated with arterial thrombosis.