Late reperfusion (>6 hours after onset) for acute myocardial infarction prevented left ventricular dilatation compared to no reperfusion (EDVI 53 vs 68 mL/m2; P<0.05), without limiting infarct size.
Cohort (n=89)
Does late reperfusion prevent left ventricular dilatation and reduce infarct size in patients with initial anterior myocardial infarction?
Late reperfusion (>6 hours) for acute anterior myocardial infarction prevents left ventricular dilatation despite not reducing infarct size.
Absolute Event Rate: 53% vs 68%
p-value: p=<0.05
BACKGROUND: While previous clinical studies have shown a possible beneficial effect of the reperfusion performed at a relatively late phase of acute myocardial infarction ("late reperfusion") in preventing left ventricular enlargement, the mechanism has not been clarified. METHODS AND RESULTS: Of 89 patients with an initial anterior myocardial infarction, reperfusion was successful in 69. These 69 were divided into three groups according to the time required to achieve reperfusion after the onset of symptoms: early-reperfused ( 6 hours from the onset to reperfusion; n = 19). The 20 patients whose infarct-related artery were occluded in the acute phase as well as 1 month later was classified as nonreperfused. Infarct size, evaluated as defect volume by 201Tl single-photon emission computed tomography 1 month after the onset, was 1593 +/- 652 units (mean +/- SD) in the late-reperfused group, significantly larger (P 6 hours after onset) did not limit infarct size or preserve left ventricular function. In contrast, the end-diastolic volume index did not differ significantly among the early-reperfused (50 +/- 15 mL/m2), intermediate-reperfused (54 +/- 14 mL/m2), and late-reperfused (53 +/- 19 mL/m2) groups; those were significantly smaller than that of the nonreperfused group (68 +/- 12 mL/m2; P < .05). Left ventriculographic data obtained in both the acute and chronic phase in 39 patients showed that left ventricular volumes increased significantly during the course of myocardial infarction only in the nonreperfused group. CONCLUSIONS: Late reperfusion appeared to prevent ventricular dilatation acute myocardial infarction independent of the limitation of infarct size.
Hirayama et al. (Wed,) conducted a cohort in initial anterior myocardial infarction (n=89). Late reperfusion (> 6 hours from onset) vs. Early reperfusion, intermediate reperfusion, and nonreperfused was evaluated on End-diastolic volume index (p=<0.05). Late reperfusion (>6 hours after onset) for acute myocardial infarction prevented left ventricular dilatation compared to no reperfusion (EDVI 53 vs 68 mL/m2; P<0.05), without limiting infarct size.