title: Immediate Versus Delayed Invasive Intervention for Non-STEMI Patients: The RIDDLE-NSTEMI Study.
abstract: OBJECTIVE
  This study aimed to assess the clinical impact of immediate versus delayed invasive intervention in patients with non-ST-segment myocardial infarction (NSTEMI).
  
  
  BACKGROUND
  Previous studies found conflicting results on the effects of earlier invasive intervention in a heterogeneous population of acute coronary syndromes without ST-segment elevation.
  
  
  METHODS
  We randomized 323 NSTEMI patients to an immediate-intervention group (<2 h after randomization, n = 162) and a delayed-intervention group (2 to 72 h, n = 161).The primary endpoint was the occurrence of death or new myocardial infarction (MI) at 30-day follow-up.
  
  
  RESULTS
  Median time from randomization to angiography was 1.4 h and 61.0 h in the immediate-intervention group and the delayed-intervention group, respectively (p < 0.001). At 30 days, the primary endpoint was achieved less frequently in patients undergoing immediate intervention (4.3% vs. 13%, hazard ratio: 0.32, 95% confidence interval: 0.13 to 0.74; p = 0.008). At 1 year, this difference persisted (6.8% in the immediate-intervention group vs. 18.8% in delayed-intervention group; hazard ratio: 0.34, 95% confidence interval: 0.17 to 0.67; p = 0.002). The observed results were mainly attributable to the occurrence of new MI in the pre-catheterization period (0 deaths + 0 MIs in the immediate-intervention group vs. 1 death + 10 MIs in the delayed-intervention group). The rate of deaths, new MI, or recurrent ischemia was lower in the immediate-intervention group at both 30 days (6.8% vs. 26.7%; p < 0.001) and 1 year (15.4% vs. 33.1%; p < 0.001).
  
  
  CONCLUSIONS
  Immediate invasive strategy in NSTEMI patients is associated with lower rates of death or new MI compared with the delayed invasive strategy at early and midterm follow-up, mainly due to a decrease in the risk of new MI in the pre-catheterization period. (Immediate Versus Delayed Invasive Intervention for Non-STEMI Patients [RIDDLE-NSTEMI]; NCT02419833).
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Emergency Department, Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Milosevic
authors.affiliation: Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Zorana
authors.initials: Z
authors.lastname: Vasiljevic-Pokrajcic
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia.
authors.forename: Dejan
authors.initials: D
authors.lastname: Milasinovic
authors.affiliation: Emergency Department, Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Institute for Medical Statistics and Informatics, Belgrade, Serbia.
authors.forename: Jelena
authors.initials: J
authors.lastname: Marinkovic
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Vladan
authors.initials: V
authors.lastname: Vukcevic
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Emergency Department, Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Branislav
authors.initials: B
authors.lastname: Stefanovic
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Emergency Department, Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Milika
authors.initials: M
authors.lastname: Asanin
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia.
authors.forename: Miodrag
authors.initials: M
authors.lastname: Dikic
authors.affiliation: Center for Medical Biochemistry, Clinical Center of Serbia, Belgrade, Serbia.
authors.forename: Sanja
authors.initials: S
authors.lastname: Stankovic
authors.affiliation: Department of Cardiology, Clinical Center of Serbia, Belgrade, Serbia; Faculty of Medicine, University of Belgrade, Belgrade, Serbia. Electronic address: gorastan@sbb.rs.
authors.forename: Goran
authors.initials: G
authors.lastname: Stankovic
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality; D018572:Disease-Free Survival; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D000072658:Non-ST Elevated Myocardial Infarction / Q000000981:diagnostic imaging / Q000401:mortality / Q000628:therapy*; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000401:mortality; D016016:Proportional Hazards Models; D012008:Recurrence; D018570:Risk Assessment; D012307:Risk Factors; D055771:Serbia; D013997:Time Factors; D061665:Time-to-Treatment; D016896:Treatment Outcome
keywords: NSTEMI; delayed intervention; immediate intervention; randomized controlled trial