Abstract
ABSTRACTRecent angiographic studies have demonstrated that intracoronary thrombus is present in the majority of patients with acute transmural myocardial infarction. In an attempt to overcome coronary artery obstruction and restore antegrade flow, streptokinase has been infused directly into the obstructed coronary artery supplying the infarct zone. We have recently analyzed the angiographic features of 27 patients with acute transmural myocardial infarction presenting within 3 hours of the onset of persistent pain. All underwent coronary angiography and infusion of streptokinase into the occluded coronary artery. Complete occlusion of the left anterior descending coronary artery was seen in all 14 patients with anterior myocardial infarction. Ten of 13 patients with inferior myocardial infarction showed complete right coronary artery occlusion. The remaining 3 patients had subtotal coronary occlusion. At the time of angiography the majority of patients showed an occlusive intraluminal convex filling defect consistent with intracoronary thrombus. Intracoronary nitroglycerin partially restored antegrade flow in only 1 patient with left anterior descending occlusion and in 1 patient with right coronary artery occlusion. Streptokinase was infused at a rate of 2,000–6,000 IU/ minute. In 20 of 27 patients (74 %) antegrade coronary flow was reestablished within 1 hour of streptokinase infusion. Chest pain was relieved and ST segments were reduced in most, but not all, of these patients. After intracoronary streptokinase infusion, the residual coronary artery stenosis was greater than 60 % in all patients. Two patients demonstrated acute reocclusion at the completion of streptokinase infusion. Five of 20 patients (25 %) developed late reocclusion 4 days to 3 months after successful clot lysis. Coronary patterns associated with reocclusion include ulcerated plaques, multiple distal vessel stenoses, irregular residual stenosis of greater than 90 %.In conclusion, angiographic studies support the hypothesis that an occlusive intracoronary thrombus is the cause of persistent myocardial injury in many patients with acute myocardial infarction. In the majority of cases, intraluminal thrombus can be identified as a convex filling defect. Selective coronary angiography can be performed safely during the acute phase of myocardial infarction and provides important information regarding the nature of the obstructive lesion in the vessel supplying the infarct zone. The benefits of early angiography and administration of intracoronary thrombolytic therapy requires further study.
Published Version
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