No evidence for a prethrombotic state in stable chronic inflammatory bowel disease.

Ulcerative colitis and Crohn's disease are associated with a high risk of thromboembolic complications. The questions whether reported risk factors such as low antithrombin III concentrations, thrombocytosis and spontaneous platelet aggregation are merely related to the activity of the inflammatory process remains to be answered. Therefore we investigated 40 patients with an established colitis or Crohn's disease, without signs of active inflammation (normal history, normal ESR and leucocyte count). Of these patients only one patient revealed thrombocytosis, six patients spontaneous platelet aggregation. All patients had normal beta-thromboglobulin and platelet factor 4 plasma levels. No other prethrombotic abnormalities were encountered. There was normal factor VIII C (increased in three patients), normal VIII C/VIII R Ag ratio (1.2), antithrombin III, normal plasminogen and normal alpha 2-antiplasmin. Normal fibrinopeptide A and B beta (15-42) plasma levels (n = 15) in these patients excluded in vivo thrombin or plasmin generation. We conclude that stable chronic inflammatory bowel disease is in general not associated with prethrombotic coagulation abnormalities.