title: Early versus delayed invasive intervention in acute coronary syndromes.
abstract: BACKGROUND
  Earlier trials have shown that a routine invasive strategy improves outcomes in patients with acute coronary syndromes without ST-segment elevation. However, the optimal timing of such intervention remains uncertain.
  
  
  METHODS
  We randomly assigned 3031 patients with acute coronary syndromes to undergo either routine early intervention (coronary angiography < or = 24 hours after randomization) or delayed intervention (coronary angiography > or = 36 hours after randomization). The primary outcome was a composite of death, myocardial infarction, or stroke at 6 months. A prespecified secondary outcome was death, myocardial infarction, or refractory ischemia at 6 months.
  
  
  RESULTS
  Coronary angiography was performed in 97.6% of patients in the early-intervention group (median time, 14 hours) and in 95.7% of patients in the delayed-intervention group (median time, 50 hours). At 6 months, the primary outcome occurred in 9.6% of patients in the early-intervention group, as compared with 11.3% in the delayed-intervention group (hazard ratio in the early-intervention group, 0.85; 95% confidence interval [CI], 0.68 to 1.06; P=0.15). There was a relative reduction of 28% in the secondary outcome of death, myocardial infarction, or refractory ischemia in the early-intervention group (9.5%), as compared with the delayed-intervention group (12.9%) (hazard ratio, 0.72; 95% CI, 0.58 to 0.89; P=0.003). Prespecified analyses showed that early intervention improved the primary outcome in the third of patients who were at highest risk (hazard ratio, 0.65; 95% CI, 0.48 to 0.89) but not in the two thirds at low-to-intermediate risk (hazard ratio, 1.12; 95% CI, 0.81 to 1.56; P=0.01 for heterogeneity).
  
  
  CONCLUSIONS
  Early intervention did not differ greatly from delayed intervention in preventing the primary outcome, but it did reduce the rate of the composite secondary outcome of death, myocardial infarction, or refractory ischemia and was superior to delayed intervention in high-risk patients. (ClinicalTrials.gov number, NCT00552513.)
authors.affiliation: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada. smehta@mcmaster.ca
authors.forename: Shamir R
authors.initials: SR
authors.lastname: Mehta
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Granger
authors.forename: William E
authors.initials: WE
authors.lastname: Boden
authors.forename: Philippe Gabriel
authors.initials: PG
authors.lastname: Steg
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bassand
authors.forename: David P
authors.initials: DP
authors.lastname: Faxon
authors.forename: Rizwan
authors.initials: R
authors.lastname: Afzal
authors.forename: Susan
authors.initials: S
authors.lastname: Chrolavicius
authors.forename: Sanjit S
authors.initials: SS
authors.lastname: Jolly
authors.forename: Petr
authors.initials: P
authors.lastname: Widimsky
authors.forename: Alvaro
authors.initials: A
authors.lastname: Avezum
authors.forename: Hans-Jurgen
authors.initials: HJ
authors.lastname: Rupprecht
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
authors.forename: Jacques
authors.initials: J
authors.lastname: Col
authors.forename: Madhu K
authors.initials: MK
authors.lastname: Natarajan
authors.forename: Craig
authors.initials: C
authors.lastname: Horsman
authors.forename: Keith A A
authors.initials: KA
authors.lastname: Fox
authors.forename: Salim
authors.initials: S
authors.lastname: Yusuf
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D000368:Aged; D000787:Angina Pectoris / Q000628:therapy; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology / Q000517:prevention & control / Q000628:therapy; D017063:Outcome Assessment, Health Care; D012306:Risk; D020521:Stroke / Q000453:epidemiology / Q000517:prevention & control; D013997:Time Factors