The effects of the angiotensin-converting enzyme inhibitor imidapril on plasma plasminogen activator inhibitor activity in patients with acute myocardial infarction

This study sought to determine whether early treatment with angiotensin-converting enzyme (ACE) inhibitors in patients with acute myocardial infarction (AMI) is useful for the improvement of fibrinolytic function, as well as left ventricular function. This study was designed to examine the levels of plasma plasminogen activator inhibitor (PAI) activity and serum ACE activity during the course of 2 weeks in 40 patiens with AMI within 12 hours after the onset of the symptom and who randomly received early treatment with either the ACE inhibitor imidapril or a placebo (20 patients in the imidapril group and 20 in the placebo group). The levels of serum ACE activity in the imidapril group decreased significantly (p<0.01) 8 hours after the administration of imidapril, and the levels 24 hours after administration were significantly lower than those in the placebo group (3.6±0.6 IU/L vs 7.4±0.8 IU/L; p<0.001). The plasma PAI activity increased gradually to peak levels 16 hours after the administration of imidapril and placebo. The levels in the placebo group decreased gradually but remained high during the study period. On the other hand, the levels of PAI activity in the imidapril group decreased rapidly and those 48 hours after administration were significantly lower than those in the placebo group (7.9±1.9 IU/ml vs 18.4±3.5 IU/ml; p<0.01). The levels of left ventricular ejection fraction about 2 weeks after admission were significantly higher in the imidapril group than in the placebo group (65.9%±2.5% vs 49.1%±4.4%; p<0.01). This study showed that imidapril, an ACE inhibitor, might be useful for the improvement of fibrinolytic function and left ventricular function in the acute phase of myocardial infarction.