Intravenous short-term infusion of streptokinase in acute myocardial infarction

Fibrinolytic Agents in Thromboembolic Diseases: Historical Perspectives and Approved Indications

Fibrinolytic agents catalyze the conversion of the inactive proenzyme plasminogen into the active protease plasmin, degrading fibrin within the thrombus and recanalizing occluded vessels. The history of these medications dates to the discovery of the first fibrinolytic compound, streptokinase, from bacterial cultures in 1933. Over time, researchers identified two other plasminogen activators in human samples, namely urokinase and tissue plasminogen activator (tPA). Subsequently, tPA was cloned using recombinant DNA methods to produce alteplase. Several additional derivatives of tPA, such as tenecteplase and reteplase, were developed to extend the plasma half-life of tPA. Over the past decades, fibrinolytic medications have been widely used to manage patients with venous and arterial thromboembolic events. Currently, alteplase is approved by the U.S. Food and Drug Administration (FDA) for use in patients with pulmonary embolism with hemodynamic compromise, ST-segment elevation myocardial infarction (STEMI), acute ischemic stroke, and central venous access device occlusion. Reteplase and tenecteplase have also received FDA approval for treating patients with STEMI. This review provides an overview of the historical background related to fibrinolytic agents and briefly summarizes their approved indications across various thromboembolic diseases.

High dose intravenous streptokinase in acute myocardial infarction--short and long term prognosis

Streptokinase (1 million international units) was given intravenously over 30 or 60 minutes to 50 patients four hours or less after the onset of acute myocardial infarction. All were aged less than or equal to 70 years and had 4 mm or greater ST segment elevation in anterior or inferior leads. Rapid (mean 95 min) ST segment resolution, which was taken to indicate reperfusion of the myocardium, occurred in 36 (72%) patients. In these 36 the average time from onset of symptoms to peak creatine kinase, creatine kinase MB, and myoglobin was 9.45 hours, whereas it was 17 hours in the 14 patients in whom indirect criteria did not indicate reperfusion. Reperfusion arrhythmias were invariably present and ventricular tachycardia developed in five patients and ventricular fibrillation in two. The infarct related artery was seen to be open in 28 (70%) of the 40 patients who had delayed coronary arteriography. The frequency of patency in the infarct related artery was no different in patients given streptokinase less than 2 hours or between 2-4 hours from onset of symptoms nor did it differ when streptokinase was infused over 30 or 60 minutes. Mean left ventricular ejection fraction was 57% in those with a patient infarct related artery and 48% in those with an occluded vessel. Eight patients subsequently underwent elective percutaneous transluminal coronary angioplasty after successful thrombolysis and six had coronary artery bypass grafting. There were nine in-hospital reocclusions of the infarct related coronary arteries. Two bleeding episodes occurred; one required transfusion. Five of the 50 patients died in hospital. All of them had had an anterior myocardial infarction; four had bifascicular block and one had right bundle branch block. During follow up, four patients died, two suddenly and two from reinfarction. During follow up (mean 15 months) the frequency of reinfarction, dyspnoea, and angina was low and there was no difference in the proportions of patients returning to work between those with an open infarct related artery and those with a closed infarct related artery. Intravenous administration of high dose streptokinase to selected patients during the acute phase of myocardial infarction is a safe, effective, and practical method of thrombolysis. It must, however, be followed by coronary arteriography to select those patients in whom percutaneous transluminal coronary angioplasty or coronary artery bypass grafting will be helpful.

Combined medical and mechanical recanalization in acute myocardial infarction

A technique of combined medical and mechanical recanalization was employed in 96 patients with acute transmural myocardial infarction. The mean time between onset of symptoms and admission to hospital was 170 +/- 65 min (X +/- SD). After 10 +/- 16 min, 250,000 U streptokinase was administered intravenously for 20 min. Intracoronary thrombolysis was commenced within 38 +/- 14 min. First coronary angiograms demonstrated reperfusion, an open vessel in 25/96 patients (26%). In 15/71 patients (21%) reperfusion occurred during thrombolysis therapy, before mechanical recanalization could be performed. Recanalization was achieved mechanically in 37/71 patients (52%) with occluded coronary vessels. In 8/71 patients (11%) mechanical recanalization failed but the vessel opened during thrombolysis. In 12/96 patients (12%), the coronary vessel remained occluded. Thus, reperfusion could be achieved in 88% of the patients. Reperfusion rate was 76% in the first 38 patients and 95% subsequently. After reperfusion, coronary thrombi were found in 25/96 patients (26%) but dissolved during thrombolysis in 16/25 patients (64%). Peripheral coronary embolism was observed in 3/25 patients (12%). For the whole group, reocclusion occurred in 8/84 patients (10%). By combined medical and mechanical recanalization, the recanalization rate could be increased with low reocclusion rate. Trends showed an improvement in regional and global left ventricular function in patients with anterior myocardial infarction.