Time course of erythrocyte antioxidant activity in patients treated by thrombolysis for acute myocardial infarction

The deleterious effects of free radicals in acute myocardial ischaemia/reperfusion are rather well known. However, the possibility that thrombolysis positively affects the recovery of blood antioxidant capacity in the later postinfarction period, and thus contributes to the better overall outcome of these patients, has not yet been investigated. We followed the time course of erythrocyte antioxidant activity in 45 patients with first acute myocardial infarction (AM1), who were treated with streptokinase. Success of thrombolysis was evaluated by noninvasive clinical signs of reperfusion using continuous vector cardiography. The patients were divided into two groups according to Successful or unsuccessful reperfusion. The control group consisted of 24 healthy subjects. Glutathione peroxidase (GPX) and superoxide dismutase (SOD) were determined immediately after admittance to the hospital (0 hours) and after subsequent thrombolytic therapy (1.5, 6, 12, and 24 hours after initiation of infusion of streptokinase), and 2, 4, and 8 days after AM1. Patients with AM1 had decreased antioxidant enzyme activity at the time of admittance to the hospital. showing that the oxidative/antioxidative balance is disturbed early during the ischemic phase of AM1. In AM1 patients without successful reperfusion, erythrocyte antioxidant enzyme activity remains low during the postinfarction period of 7 days. It call be concluded that prolonged ischemia reduces antioxidant enzyme activity. AM1 patients with successful reperfusion have a significant rise in the activity of antioxidant enzymes within the first hours after thrombolysis, followed by a decrease until the third postinfarction day. During the subsquent postinfarction period, erythrocyte antioxidant activity gradually recovered and reached control levels. These beneficial effects of reperfusion oil erythrocyte antioxidant status might contribute to the better overall prognosis of these patients.