Persistent activation of coagulation mechanism in unstable angina and myocardial infarction

Background: The blood coagulation system is activated in the acute phase of unstable angina and acute myocardial infarction. However, it remains unclear whether augmented function of the hemostatic mechanism serves only as a marker of the acute thrombotic episode or whether a hypercoagulable state persists for a prolonged period after clinical stabilization. Methods and Results: We prospectively measured the plasma concentrations of prothrombin fragment 1+2 (F(1+2)) and fibrinopeptide A (FPA) in consecutive patients presenting with unstable angina (n=80) or acute myocardial infarction (n=32), respectively. At 6 months, plasma determinations were repeated in patients experiencing an uneventful clinical course (unstable angina, n=57; myocardial infarction, n=23). We quantitated the plasma levels of F(1+2) and FPA in control patients with stable angina (n=37) or healthy individuals (n=32) who were matched for age and sex. The median plasma concentrations of F(1+2) and FPA are significantly higher in patients presenting with unstable angina (F(1+2), 1.08 nmol/L; FPA, 2.4 nmol/L) or acute myocardial infarction (F(1+2), 1.27 nmol/L; FPA, 3.55 nmol/L) compared with patients with stable angina (F(1+2), 0.74 nmol/L; FPA, 1.3 nmol/L; P