Although there are some data on prevalence of portosplenomesenteric venous thrombosis (PSMVT) in patients with acute pancreatitis (AP), the progression of PSMVT in patients who have and have not received anticoagulants has not been studied systematically. We evaluated the prevalence and natural history of PSMVT in a well-defined cohort of individuals with AP.

In a retrospective study, we analyzed data from the University of Pittsburgh Medical Center on 162 patients with a sentinel attack of AP from 2003–2010. Data were collected on patient demographics, clinical presentation, etiology, clinical course, and outcomes. One hundred twenty-two patients underwent contrast-enhanced computed tomography; the scans were reviewed to identify thromboses and/or narrowing of splanchnic veins (splenic, superior mesenteric, and portal).

PSMVT was detected in 22 patients overall (14%; 18% among patients who underwent contrast-enhanced computed tomography). Median time to detection of PSMVT was 17 days (interquartile range, 11–40 days). PSMVT formed most frequently in the splenic vein (19 of 22, 86%), followed by portal (8 of 22, 36%) and superior mesenteric (6/22, 27%) veins. Development of PSMVT was associated with presence (21 of 22, 95%), location, and extent of pancreatic necrosis. Fifty-three percent of patients (21 of 40) with necrosis developed PSMVT. Anticoagulants were administered infrequently (6 of 22, 27%) and always for indications unrelated to PSMVT. Most patients with PSMVT developed collateral veins (19 of 22, 86%), and 27% (6 of 22) were found to have varices during endoscopic evaluation, but clot resolution was infrequent (2 of 22, 9%). No patient developed complications directly related to PSMVT.

PSMVT develops in about half of patients with necrotizing AP and is rare in the absence of necrosis. Despite infrequent administration of anticoagulants, complications directly related to PSMVT are rare.