Thrombin activity throughout the acute phase of acute ST-elevation myocardial infarction and the relation to outcome

Abstract

Background: Thrombin and plasmin play a central role in ongoing thrombosis and platelet activation in patients with acute ST-elevation myocardial infarction (STEMI). Data of thrombin and plasmin activity in the early course of STEMI and the relation to outcome are scarce.Methods: We included 68 consecutive patients (53 male, 59 ± 11.4 years) with STEMI who underwent acute catheter-based reperfusion therapy within the first 12 h after onset of symptoms. Blood samples were taken at admission and after 4, 8, 12 and 24 h. Thrombin activity and generation was measured by changes in the thrombin/antithrombin-III complex (TAT) and prothrombin fragment (F1.2); plasmin was measured by changes in the plasmin-α2/antiplasmin complex (PAP). A follow-up with respect to the combined primary endpoint consisting of death, acute myocardial infarction or urgent need for revascularization up to 6 weeks post-discharge was carried out.Results: TAT values showed no significant change over time in patients with and without the primary endpoint but there was a borderline difference between these groups at 4 h after admission (event group 9.0 vs no event group 4.7 μg l−1, p = 0.057). F1.2 values were different between groups only after 24 h (event group 1.5 vs no event group 0.9 nmol l−1, p = 0.028) and did not differ in serial sampling of 24 h. PAP values were higher in patients with events after 4 and 8 h and declined over time in the group without events (p <0.001). Odds ratios (OR) with respect to the primary endpoint were highest for TAT >4.8 μg l−1 at 0 h and TAT >8.4 μg l−1 at 4 h (OR 7.1, 95% confidence interval (CI) 1.5–34, p = 0.015 and OR 5.5, 95% CI 1.5–20.0, p = 0.01, respectively). The predictive value of plasmin concentrations were equally high after 4 h (PAP >962 μg l−1; OR 6.8, 95% CI 1.8–26.2, p = 0.005) and 8 h (PAP >495 μg l−1, OR 6.7, 95% CI 1.4–32.9, p = 0.024). Values for F1.2 were only predictive after 24 h (F1.2 >0.85 nmol l−1, OR 13, 95% CI 1.4–117.8, p = 0.023).Conclusions: Markers of thrombin and plasmin activity in acute STEMI are related to outcome. The marker for thrombin generation F1.2 becomes a significant predictor of outcome at 24 h after admission, reflecting the potentially adverse effects of ongoing thrombin generation. This underlines the potential for direct thrombin inhibition and individualization of treatment by thrombin markers in STEMI.