Activation of thrombosis and fibrinolysis following brain infarction

Abstract

To clarify the sequence of alterations in the thrombotic and fibrinolytic systems after acute brain infarction, we prospectively examined sequential changes in coagulatory markers in 38 patients suffering from cardioembolic infarcts (CEI), 41 patients with atherothrombotic infarcts (ATI), 58 patients with lacunar infarcts (LI), and 32 age-matched controls. The plasma level of thrombin–antithrombin III complex (TAT), fibrinopeptide A (FpA), D-dimer, fibrin degradation products-E (FDP-E), fibrinogen, α2-plasmin inhibitor–plasmin complex (PIC), and percent activity of antithrombin III (AT-III) were measured within 48 h, at 1 week, and at 3 weeks after the stroke onset. Significantly elevated levels of TAT and FpA, which are both markers of thrombin formation, were observed in CEI patients, and these elevated levels were associated with increasing D-dimer levels for 3 weeks ( P<0.0001). D-Dimer in CEI patients was significantly elevated compared to control, LI and ATI levels within 48 h ( P<0.001). Percent activity of AT-III was significantly decreased in CEI patients for 3 weeks compared to this activity in controls, LI and ATI ( P<0.001). TAT and FpA also increased significantly within 48 h in ATI subjects and declined thereafter. A significant elevation of FDP-E ( P<0.001) and D-dimer ( P<0.05, P<0.01) was detected in parallel with increasing fibrinogen for 3 weeks. However, there was no significant depletion of percent activity of AT-III in ATI. In LI subjects, no significant elevation of TAT, D-dimer or FDP-E were observed within 1 week. PIC increased significantly in three subtypes of brain infarcts, but did not differ significantly among the three subtypes for 3 weeks. An accurate assessment of sequential alterations in thrombotic and fibrinolytic markers in the acute stage of brain infarct should contribute to the clinical diagnosis of brain infarct subtype. Alterations in these markers in response to activation of the coagulatory system are attributable to the different pathogenesis of ischemic stroke.