Association of patency of the infarct-related coronary artery with plasma levels of plasminogen activator inhibitor activity in acute myocardial infarction

Abstract

To examine the fibrinolytic capacity in patients with acute myocardial infarction (AMI), baseline levels of plasma plasminogen activator inhibitor (PAI) activity and tissue-type plasminogen activator (t-PA) antigen were measured in 47 patients with Q-wave AMI who underwent emergent coronary angiography 3.0 ± 0.2 hours after the symptom onset. They received intracoronary injection of urokinase if their infarct-related arteries were occluded. They were classified into 3 groups according to the patency of the infarct-related artery before and after thrombolytic therapy: the patent group (13 patients), the recanalized group (23 patients) and the occluded group (11 patients). The mean level of plasma PAI activity (IU/ml) was higher in patients with AMI as a whole than in the control group (12.8 ± 1.6 vs 5.4 ± 0.5, p < 0.01). The level was lower in the patent group (3.0 ± 1.1) and higher in the recanalized (18.6 ± 2.2) and occluded (10.8 ± 2.5) groups than in the control group (each p < 0.01). The level was lower in the occluded than in the recanalized group (p < 0.01) and 62% of the patients in the occluded group had levels within range of the control group. The mean level of plasma t-PA antigen (ng/ml) was higher in patients with AMI as a whole than in the control group (10.3 ± 0.8 vs 5.8 ± 0.3, p < 0.01). There was no difference in the level among the 3 groups with AMI. Thus, this study indicates that there is a significant relation between the baseline plasma fibrinolytic capacity and the patency of the infarct-related artery before and after thrombolytic therapy.