Plasma lipoprotein(a) levels and fibrinolytic activity in patients with unstable angina.

The relationship between plasma Lipoprotein(a) (Lp(a)) levels and plasminogen activator inhibitor (PAI) activity and tissue plasminogen activator (t-PA) antigen levels were studied in 15 patients with unstable angina. Plasma levels of Lp(a) (mg/dl) were significantly higher in patients with unstable angina after treatment 2 weeks than on admission (19.7 +/- 2.8 vs 14.6 +/- 2.3, p < 0.01). On the other hand, the plasma levels of PAI activity (IU/ml) and t-PA antigen (ng/ml) in patients with unstable angina were significantly higher on admission than after treatment (PAI activity: 11.4 +/- 1.4 vs 7.7 +/- 1.5, t-PA antigen: 8.7 +/- 0.9 vs 7.0 +/- 0.9, p < 0.01). We conclude that patients with unstable antigen have reduced fibrinolytic capacity, as indicated by increased PAI activity, and that the plasma Lp(a) level may be decreased due to binding with fibrin during the acute stage of unstable angina.