This study assessed the relative efficacy of 3 doses of intravenous streptokinase in causing hypofibrinogenemia and coronary reperfusion in patients with acute myocardial infarction. Accordingly, 56 patients (50 men and 6 women, ages 58 ± 10 years [mean ± standard deviation]) with evolving acute myocardial infarction and chest pain ≤5 hours in duration were assigned to receive varying doses of streptokinase. Twenty were administered 500,000 units during 145 minutes, 18 were given 750,000 units during 30 minutes and 18 received 1.5 million units in 60 minutes of streptokinase. Serum creatine kinase was measured on admission and 6, 12, 18 and 24 hours after the initiation of streptokinase. The time intervals from onset of pain to peak creatine kinase and from streptokinase administration to peak creatine kinase were used to determine the occurrence of reperfusion. The plasma fibrinogen concentration was measured 30, 60, 90 and 120 minutes after the initiation of streptokinase. For the 3 groups, the time from onset of pain to peak creatine kinase was <17 hours and the time from streptokinase to peak creatine kinase was 6 or 12 hours in 15 (75%), 16 (89%) and 12 patients (67%), respectively (differences not significant). The plasma fibrinogen concentration decreased to 45 ± 34 mg/dl, 19 ± 14 mg/dl and 29 ± 43 mg/dl, respectively, during the 2 hours after streptokinase was begun (p < 0.05 for the first versus the second and third values). Thus, if sufficient streptokinase is given to produce a systemic fibrinolytic state, smaller doses (500,000 and 750,000 units) are as effective as larger ones (1.5 million units) in inducing coronary reperfusion. In addition, 750,000 and 1.5 million units produce a similar degree of hypofibrinogenemia, so that the administration of >750,000 units of intravenous streptokinase to patients with acute myocardial infarction appears to offer no demonstrable advantage.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine