PATENCY AND REINFARCTION IN LATE-ENTRY MYOCARDIAL INFARCT PATIENTS TREATED WITH REPERFUSION THERAPY

Patency of the infarct-related vessel is associated with a more favora ble long-term prognosis after acute myocardial infarction (AMI). High infarct vessel patency is reported for early reperfusion therapy, but data on patency and its possible effect on clinical outcome are less a bundant for patients Presenting late after the acute event. The aim of this study was to investigate whether time to reperfusion is related to infarct-vessel patency and clinical outcome. This study compares 26 8 patients who presented with symptoms of AMI within six hours after t he onset of symptoms (Early) with 33 patients who had reperfusion ther apy for signs of ongoing ischemia more than six hours after the start of chest pain (Late). At follow-up coronary angiography, flow through the infarct-related vessel was assessed according to the thrombolysis in myocardial infarction (TIMI) classification. Vessels were considere d occluded if TIMI flow grade 0 or 1 was present. Follow-up angiograph y was performed in 95% of patients after a mean of forty-eight days. T he infarct-related vessel was occluded in 41% of the late-entry patien ts (13 of 32), and in 17% of those presenting early (44 of 252), (P=0. 01; relative risk [RR]: 2.50; 95% confidence interval [CI]: 1.26 to 6. 83). This was associated with a higher rate of recurrent myocardial in farction in late-entry patients: 27% (9 of 33), compared with 9% (25 o f 268) in the early group (P=0.005; RR: 2.94; 95% CI: 1.50 to 5.81). T hus, in the present study, late reperfusion therapy; (after six hours) was associated with a higher recurrent myocardial infarction rate and a lower infarct vessel patency rate, compared with early treatment of patients.