title: Unanswered questions for management of acute coronary syndrome: risk stratification of patients with minimal disease or normal findings on coronary angiography.
abstract: BACKGROUND
  The prognostic implication of chest pain associated with normal or near-normal findings on angiography is still unknown. We explored outcomes and methods of risk stratification in patients with nonobstructive coronary artery disease in the setting of non-ST-segment elevation acute coronary syndromes.
  
  
  METHODS
  Data were pooled from 3 Thrombolysis in Myocardial Infarction (TIMI) trials (TIMI 11B, TIMI 16, and TIMI 22). Angiographic data were available on 7656 patients with non-ST-segment elevation acute coronary syndromes. The primary end point of this analysis was the composite of the rates of death, myocardial infarction, unstable angina requiring rehospitalization, revascularization, and stroke at 1-year follow-up. Outcomes were evaluated by mean of the TIMI risk score for developing at least 1 component of the primary end point.
  
  
  RESULTS
  Angiographic findings showed that 710 (9.1%) of 7656 patients had nonobstructive coronary artery disease; 48.7% of these had normal coronary arteries (0% stenosis), and 51.3% had mild coronary artery disease (>0% to <50% stenosis). A primary end-point event occurred in 101 patients (12.1%). It is noteworthy that a 2% event rate of deaths and myocardial infarctions had occurred in these patients at the 1-year follow-up. Event rates of death and myocardial infarction increased significantly as the TIMI risk score increased from 0.6% for a score of 1 to 4.0% for a score greater than 4.
  
  
  CONCLUSIONS
  Patients with non-ST-segment elevation acute coronary syndromes with nonobstructive coronary artery disease detected by angiography have a substantial risk of subsequent coronary events within 1 year. The risk is not univariately high, and the TIMI risk score helps to reveal patients at high risk.
authors.affiliation: Department of Internal Medicine, Cardioangiology and Hepatology, University of Bologna, Italy. raffaele.bugiardini@unibo.it
authors.forename: Raffaele
authors.initials: R
authors.lastname: Bugiardini
authors.forename: Olivia
authors.initials: O
authors.lastname: Manfrini
authors.forename: Gaetano M
authors.initials: GM
authors.lastname: De Ferrari
mesh_terms: D000789:Angina, Unstable / Q000453:epidemiology*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000453:epidemiology; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology*; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D020521:Stroke / Q000453:epidemiology