[Clinical presentation of unstable angina may influence the formation of thrombin during spontaneous episodes of ischemia].

In order to evaluate whether different clinical presentations of unstable angina are associated with a different degree or pattern of activation of the hemostatic, fibrinolytic and inflammatory systems, we measured plasma levels of thrombin-antithrombin III, plasmin-alpha2- antiplasmin complexes and C-reactive protein, as markers of activation of coagulation, fibrinolysis and inflammation respectively, in two groups of patients: 7 patients with de novo unstable angina (Group 1) and 7 patients with destabilizing unstable angina (Group 2). Blood samples were taken on admission for measuring levels of C-reactive protein and during ischemic episodes at the onset of ECG changes and pain (0 min) and after 5, 15 and 60 min in order to assess the peak values of thrombin-antithrombin III and plasmin-alpha2-antiplasmin during the episode. Thrombin-antithrombin III levels in Group 1 were 1.8 microgram/l (0.3-4.15) at 0 min and increased to 17 micrograms/l (2.8-60) after 5 to 15 min (p = 0.013); conversely thrombin-antithrombin III levels in Group 2 were 2.15 microgram/l (1.4-3.8) at 0 min and raised to 4 micrograms/l (2-43) after 5 to 15 min (NS). No significant differences in both groups were observed in plasmin-alpha2-antiplasmin levels (Group 1:650 micrograms/l, ranged 492-956, at 0 min vs 670 microgram/l, range 415-977, at peak; Group 2: 480 micrograms/l, range 274-955, at 0 min vs 502 micrograms/l, range 304-1027, at peak; NS). Inversely, C-reactive protein levels on admission were 4 mg/dl (range 2-27) in Group 1, and 1 mg/dl (range 0.6-4) in Group 2 (p = 0.006). In conclusion, patients with de novo unstable angina have significantly enhanced thrombin (but not plasmin) production during spontaneous ischemic episodes than patients with destabilizing unstable angina. Furthermore, patients with de novo unstable angina have enhanced acute phase responses than patients with destabilizing unstable angina. Our data suggest that different pathogenetic mechanisms may be responsible for acute ischemic episodes in unstable angina and may explain different response to antithrombotic therapy in unstable angina patients.