RESUMO
In 72 patients who received streptokinase within 6 hours of the onset of an acute myocardial infarction (AMI), the relationship between the presence of a previous coronary event and the severity of the residual coronary artery stenosis was studied. Fifty-five patients were either asymptomatic or had recent onset angina (less than 5 days) before AMI (group A) and 17 patients had chronic angina (greater than 1 year) before AMI (group B). Coronary angiograms were performed at 20 days (range 15 to 25 days). Patency of the infarct-related artery was greater in group A: 43 of 55 patients (78%) versus 8 of 17 patients (47%) in group B (p less than 0.05). Residual stenosis was less than 70% in 21 patients of group A (49% of patent arteries), whereas it manifested in none of eight patients with patent arteries in group B (p less than 0.01). This suggests that thrombosis was a major component of the coronary artery narrowing in group A patients, while it is more likely that thrombus only completes a previously severe (greater than 70%) coronary artery stenosis in patients with long-standing angina before AMI.
