We evaluated the effectiveness of early intravenous administration of 750,000 units of streptokinase in 53 patients with acute myocardial ischemia treated by a mobile-care unit at home (9 patients) or in the hospital (44 patients). Treatment was begun an average (+/- S.D.) of 1.7 +/- 0.8 hours from the onset of pain. Non-Q-wave infarctions developed subsequently in eight patients, whereas all the others had typical Q-wave infarct patterns. In 81 per cent of the patients the infarct-related artery was patent at angiography performed four to nine days after admission. Vessel patency was independent of the time of treatment, but residual left ventricular function was time dependent. Patients treated less than 1.5 hours after the onset of pain had a significantly higher ejection fraction (56 +/- 15 vs. 47 +/- 14 per cent; P less than 0.05) and infarct-related regional ejection fraction (51 +/- 19 vs. 34 +/- 20 per cent; P less than 0.01) and a lower QRS score (5.6 +/- 4.9 vs. 8.6 +/- 5.5; P less than 0.01) than patients receiving treatment between 1.5 and 4 hours after the onset of pain. Patients treated earlier by the mobile-care unit also had better-preserved left ventricular function than patients treated in the hospital. We conclude that thrombolytic therapy with streptokinase is most effective if given within the first 1.5 hours after the onset of symptoms of acute myocardial infarction.
Coronary restenosis after balloon angioplasty is a slow process that develops over a few months. In some patients, with an initially successful angioplasty, an artery that originally had only moderate stenosis becomes totally occluded as a result of restenosis. This report describes 16 such patients out of 415 dilated lesions with late angiographic follow-up. Ten patients presented with stable angina pectoris, 5 had unstable angina and only one was admitted with a small myocardial infarction. Visible collaterals were present in 15 patients. Except for the patient who sustained myocardial infarction, none of the late angiograms showed the typical morphological features of acute lesion. We conclude that total coronary occlusion late after successful angioplasty of an artery that was moderately narrowed is rare. The ‘restenotic’ occlusion is a slow process that stimulates collateral formation and thus the risk of myocardial infarction is small.
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