OBJECTIVETo compare the effect and safety of early intervention and delayed intervention in patients with non-ST segment elevation acute coronary syndrome.

METHODSIn this multicenter randomized trial, patients diagnosed as non-ST segment elevation acute coronary syndrome were randomly assigned to undergo early intervention (coronary angiography ≤ 24 hours after randomization, n = 446) or delayed intervention (coronary angiography ≥ 36 hours after randomization, n = 369). The primary outcome was a composite of death, myocardial infarction or stroke at 180 days. The secondary outcome was death, myocardial infarction, refractory ischemia, stroke or revascularization at 180 days.

RESULTSBaseline clinical characteristics were comparable between the two groups. Incidence of both primary (9.0% vs. 14.6%, P = 0.01) and secondary which was a composite of death, myocardial infarction or refractory ischemia (14.6% vs. 22.0% P = 0.01) endpoints were significantly lower in early intervention group than in delayed intervention group. Incidence of myocardial infarction was significantly lower in early intervention group than in delayed intervention group (5.2% vs. 10.8%, P = 0.00). Another secondary outcome which was a composite of death, myocardial infarction, refractory ischemia, stroke or revascularization was similar between the two groups (26.7% vs. 30.4%, P = 0.25).

CONCLUSIONCompared to delayed intervention group, early intervention reduced incidence of myocardial infarction but did not affect the incidence of death, stroke or refractory ischemia in patients with non-ST segment elevation acute coronary syndrome.