Endogenous thrombin potential in the assessment of hypercoagulability in systemic lupus erythematosus

Endogenous thrombin potential (ETP) is a measurement of thrombin formation capacity of plasma and may be increased in congenital and acquired hypercoagulable states. We assessed whether ETP was associated with antiphospholipid antibodies (aPL) and with thrombosis history in SLE. ETP was performed in 130 SLE patients using a Siemens ETP Assay on BCS Coagulation System analyzer, that is equipped with software to analyze different components of the coagulation wave form, including lag-time (time to initiate thrombin generation), T-max (estimate of enzymatic rate), C-max (measurement of peak height), and area under the curve (total thrombin formation). Higher T-lag values were found with deep venous thrombosis (DVT) (33.6 +/- 15.9 vs. 22.9 +/- 14.8, P = 0.0018), myocardial infarction (MI) (43.6 +/- 36.4 vs. 24.6 +/- 15.1, P = 0.0855) and stroke (27.5 +/- 13.5 vs. 24.5 +/- 15.8, P = 0.4883) than without. T-max was also higher in patients with DVT (68.4 +/- 21.9 vs. 56.5 +/- 24.4, P = 0.0300), and MI (123.8 +/- 77.0 vs. 57.7 +/- 22.1, P > 0.0001) compared to those without. ETP T-lag and T-max were higher for patients with aPL. ETP T-lag and T-max were associated with both venous (DVT) and arterial (stroke, MI) thrombosis in SLE and with aPL. This suggests that ETP measures should now be explored prospectively to determine their predictive value for future thrombosis in SLE.