Is prophylactic anticoagulation indicated in patients with frequent ulcerative colitis flares?

Background: We know that inflammatory bowel disease (IBD) is a risk for incident and recurrent venous thromboembolism (VTE). What is not clearly established is whether the IBD needs to be 'active' in order for it to be a risk factor, e.g. would patients who have had proctocolectomy (and perhaps no e...