title: Comparison of a 6-hour and 9-hour protocol for evaluation of moderate-to-low risk chest pain patients in an emergency department diagnostic unit.
abstract: OBJECTIVE
  To compare the 30-day outcomes of patients enrolled in a 6-hour and 9-hour emergency department (ED)-based chest pain centre (CPC) protocol.
  
  
  METHODS
  All patients with the chief complaint of chest pain, who were older than 25 years, or with cocaine usage within 96 hours of initial presentation, were eligible for enrolment. Exclusion criteria included acute ST-segment elevation or depression >1 mm in 2 contiguous leads, history of coronary artery disease (CAD), haemodynamic instability or clinical syndromes consistent with unstable angina. Outcomes included ED disposition and cardiac events at 30 days (defined as acute myocardial infarction (AMI), percutaneous trans-luminal coronary angiography (PTCA), coronary artery bypass graft surgery (CABG),ventricular tachycardia or fibrillation (VT/VF) arrest, congestive heart failure (CHF) admission or cardiac-related death). The 9-hour protocol consisted of ST-segment monitoring,serial CK-MB draws at 0, 3,6 and 9 hours as well as a graded exercise test (GXT) prior to ED disposition. The 6-hour protocol eliminated the 9-hour serum marker determination, included cardiac Troponin-I (cTn-I) and allowed a GXT, 3 hours earlier. Follow-up was obtained by medical record review, phone contact, letter and also review of national and state death registries.
  
  
  RESULTS
  The 9-hour protocol (October 1991-December 1997) included 2,133 patients and the 6-hour protocol (January 1998- August 1998) had 184 patients enrolled. The 6-hour protocol was not different from the 9-hour one in terms of percentage admissions (9-hour: 310, 14.5%; 6-hour: 33, 17.9%; p=0.213), Coronary Care Unit admission (9-hour: 59, 2.8%; 6-hour: 5, 2.7%; p=0.303) or 30-day cardiac events (9-hour: 38, 1.9%; 6-hour: 2, 1.3%; p=0.605).
  
  
  CONCLUSIONS
  The 6-hour CPC strategy is an effective and safe evaluation method for patients at low to moderate risk for acute coronary syndromes.
authors.affiliation: Department of Emergency Medicine, Singapore General Hospital. f_lateef@hotmail.com
authors.forename: F
authors.initials: F
authors.lastname: Lateef
authors.forename: A B
authors.initials: AB
authors.lastname: Storrow
authors.forename: K
authors.initials: K
authors.lastname: Malone
authors.forename: T
authors.initials: T
authors.lastname: Liu
authors.forename: B W
authors.initials: BW
authors.lastname: Gibler
mesh_terms: D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D002637:Chest Pain / Q000209:etiology*; D002985:Clinical Protocols / Q000592:standards*; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000097:blood / Q000150:complications* / Q000175:diagnosis*; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D004638:Emergency Treatment / Q000379:methods* / Q000592:standards; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000209:etiology; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods* / Q000592:standards; D010343:Patient Admission; D012307:Risk Factors; D017180:Tachycardia, Ventricular / Q000209:etiology; D013997:Time Factors; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood; D014693:Ventricular Fibrillation / Q000209:etiology
chemical_list: D007527:Isoenzymes; D019210:Troponin I; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form