Streptokinase-induced transient aggravation of myocardial injury

We examined the relationship between streptokinase infusion, intensity of myocardial injury and systemic hypotension in patients receiving streptokinase for treatment of evolving acute myocardial infarction. Twenty consecutive patients treated with streptokinase for evolving acute myocardial infarction received continuous blood pressure and S-T segment monitoring of the 12 lead electrocardiogram (ECG) for at least 5 h, commencing prior to commencement of the streptokinase infusion. Aggravation of injury, manifested both by episodic increases in S-T segment elevation on the electrocardiogram (ECG) (P < 0.001), and in mean S-T segment elevation (P < 0.05) occurred within the first 20 min after initiation of streptokinase infusion. Hypotension also occurred transiently in most patients, with a mean minimum systolic blood pressure of 92 +/- 22 (S.D.) mmHg occurring 16 +/- 5 min after commencement of streptokinase. There was no correlation between the extent of aggravation of injury and that of hypotension. All patients showed ECG evidence of reperfusion, with a reduction of S-T elevation in the reference lead to 50% of maximal value, after a median of 62 min (range 9-174 min). It is concluded that streptokinase aggravates injury prior to reperfusion, although probably not via the induction of hypotension: It is possible that this effect contributes to the 'early hazard' of thrombolytic therapy.