Increased thrombin generation in inflammatory bowel diseases.

Background: Inflammatory bowel diseases (IBD) are characterized by an increased thrombotic risk of uncertain etiology. Endogenous thrombin potential (ETP), a parameter of the thrombin generation curve, represents a new tool in the evaluation of thrombotic and bleeding disorders.

Aims: To study ETP in IBD patients and to correlate the results with clinical and biochemical features.

Methods: Seventy-four IBD patients (37 ulcerative colitis and 37 Crohn's disease) and 74 sex- and age-matched healthy individuals. ETP was measured upon activation of coagulation with small amounts of tissue factor and phospholipids in the presence or absence of thrombomodulin; results were expressed as nM thrombin.minutes.

Results: Mean+/-SD ETP values were significantly higher in patients (1,499+/-454) than controls (1,261+/-385) (p<0.001) only when the test was performed in the presence of thrombomodulin. ETP evaluated as ratio (with/without thrombomodulin), taken as an index of hypercoagulability, was significantly higher in patients (0.69+/-0.14) than controls (0.62+/-0.18) (p<0.006). Patients with increased C-reactive protein (CRP) had significantly higher mean ETP (1,721+/-458) than those with normal CRP (1,357+/-394) or controls (1,261+/-385) (p<0.001). Patients who at the time of blood sampling were classified as having a clinically active disease had ETP higher than those who were quiescent (1,655+/-451 versus 1,388+/-427, p<0.001) or controls (1,261+/-385, p<0.001).

Conclusions: ETP measured in the presence of thrombomodulin or as ratio (with/without thrombomodulin) is increased in IBD patients, mainly in those with increased CRP or active disease. It may be considered as a candidate test for prospective studies aimed at assessing the risk of thrombosis in IBD patients.