EFFECT OF METOPROLOL ON FIBRINOLYTIC-ACTIVITY IN HYPERTENSIVE PATIENTS WITH HIGH PLASMINOGEN-ACTIVATOR INHIBITOR ACTIVITY

Aim of the study: to investigate the effect of metoprolol on plasminog en activator inhibitor-1 (PAI-1) activity, PAI-1 antigen, tissue plasm inogen activator (t-PA) activity and t-PA antigen before and after ven ous occlusion for 10 min. Study design: 14 hypertensive patients with high PAI-1 activity level (PAI-1 greater than or equal to 10 U/ml) wer e treated in two 3-week periods with metoprolol succinate (95 mg/d) or placebo in a double blind cross-over study. All fibrinolytic variable s were also examined after 3 months treatment with metoprolol. Results : venous occlusion gave a reduction in PAI-1 activity and increases in PAI-1 antigen, t-PA capacity and t-PA release, irrespective of drug t reatment. No statistical significant differences between metoprolol an d placebo were found for any of the fibrinolytic variables. Conclusion : in this study the selective beta(1)-blocker metoprolol did not inhib it t-PA release after venous occlusion and had no influence on the mea sured fibrinolytic variables in hypertensive patients with high PAI-1 levels. This suggests that other mechanisms than fibrinolytic are resp onsible for the preventive action of metoprolol on cardiovascular morb idity and mortality.