Fibrinolytic System And Acute Myocardial Infarction

The development and progress of acute myocardial infarction (AMI) is closely related to inhibition of fibrinolytic system. It is very important to monitor the fibrinolytic activity of the patients with AMI. The changes of plasma t-PA and PAI activity were observed in 22 cases of AMI for 3 weeks after onset. The role of thrombolytic effect of SVATE in the treatment of the patients with AMI was studied.The results showed; 1.The t-PA activity was markedly decreased at the first day after onset, especially in those complicated with cardiogenic shock, heart failure, high degree of A-V block or severe ventricular arrhythmias, which we divided into subgroup AMI-A. The t-PA activities were below normal value in the whole period of observation. 2.The PAI activities were obviously increased in first three days, particularly in AMI-A subgroup. 3.The activities of t-PA and PAI were correlated well with the severity and prognosis of AMI. The PAI activity in those patients who died was twice as high as those in healthy control subjects. The infarct size was calculated using Selvester's QRS scoring system, the scoring of AMI-A subgroup and AMI-B subgroup without complications were 13.4± 3.41 and 7.57±2.44, respectively (P<0.01), each score represents 3 percent of the left ventricle. The more extensive the infarct size was, the more prominent the change of t-PA and PAI activities was. The baseline of PAI activity was still related to the patency of infarct coronary artery after thrombolytic therapy. Conceivably, higher levels of PAI may interfere with the natural thrombolytic process and make pharmacologic thrombolytic intervention less effective. 4.SVATE could enhance the activity of fibrinolytic system, slightly inhibit platelet functions and decrease the level of plasma fibrinogen. The degree of enhancement of fibrinolytic system was not so great as that of UK at early stage of AMI, so SVATE is not an effective thrombolytic agent.