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Background It has been well-established that aspirin therapy reduces the risk of vascular events in the acute phase of evolving acute myocardial infarction (AMI). However, the adequate dose of aspirin for AMI has not yet been determined. Methods To compare alternate-day aspirin 81 mg and daily aspirin 162 mg on the effects of in-hospital cardiovascular events after AMI, we performed a multicenter, open-label, controlled, randomized clinical trial. The aspirin regimen was started immediately, with 162 mg on the first and second day, and randomly allocated to alternate-day aspirin 81 mg and 162 mg aspirin daily after the third day and continued in the hospital. Three hundred sixty-five patents with AMI were allocated to alternate-day aspirin 81 mg and 386 patients with AMI to daily aspirin 162 mg. Results The observation period was 29.9 ± 0.6 days. There were no statistically significant differences between the 2 treatment groups in age, sex, hours from onset to admission. Killip classification, number of thrombolytic therapies, percutaneous transluminal coronary angioplasty, and other drugs (nitrates, calcium antagonists, β-blockers, and angiotensin-converting enzyme inhibitors). There were also no differences between the 2 groups in the incidence of refractory angina to drug therapy, reinfarction, cerebral vascular accidents, and occurrence of side effects. However, cardiac death occurred in 9 patients in the daily aspir n 162 mg group but in none of those in the alternate-day aspir n 81 mg group (P = .0037). On the other hand, fatal cereb-al infarction occurred in 2 patients in the alternate-day 81 mg aspirin group but in none of those in the daily aspirin 162 mg group. Conclusions We conclude that this study, although underpowered to show meaningful differences in outcome, did not show any difference in in-hospital cardiovascular events with alternate-doy aspirin 81 mg compared with daily aspirin 162 mg.

THE FACTORS RESPONSIBLE FOR EARLY OCCLUSION OF THE INFARCT VESSEL AFTER emergency percutaneous transluminal coronary angioplasty (PTCA) were retrospectively examined in 191 patients with acute myocardial infarction. During the 24-hour period after the initial balloon inflation, 47 patients (25%) had occlusion of the vessel (occlusion group), whereas 144 did not (nonocclusion group). The former patients immediately underwent repeat PTCA, which was successful in 37. Univariate correlates of early occlusion were a shorter time interval between the onset of symptoms and PTCA (3.5 +/- 2.2 vs 4.5 +/- 2.9 hours, p = 0.025), right coronary artery involvement (53% vs 30%, p = 0.015), prior thrombolytic therapy (49% vs 32%, p = 0.035), and undersized inflation (43% vs 17%, p < 0.001). With multivariate analysis the three independent predictors were undersized inflation (p < 0.001), right coronary artery involvement (p = 0.004), and a shorter time interval until PTCA (p = 0.011). Thus patients undergoing early PTCA and having right coronary artery involvement appear to be at greater risk of having early occlusion. Thrombolytic agents and undersized inflation may also play an important role in its development.

Early restenosis after successful percutaneous transluminal coronary angioplasty (PTCA) without antecedent thrombolytic therapy in patients with acute myocardial infarction (AMI) was assessed by performing in-hospital cardiac catheterization in 62 (83%) of 70 consecutive patients. Specific attention was focused on the effectiveness of the intracoronary administration of urokinase in cases with angiographic residual thrombus after successful direct PTCA. The following two treatment regimens were used: PTCA alone (43 patients) and PTCA followed by the intracoronary infusion of urokinase (27 patients). The rate of early restenosis was higher after successful direct PTCA alone (28%) than after direct PTCA followed by intracoronary urokinase (5%). Bleeding complications were no different between the two groups. These findings suggest that intracoronary urokinase can be effective in reducing early restenosis in patients with angiographic residual thrombus after successful direct PTCA. Therefore early restenosis may be related to residual intracoronary thrombus.