title: Validating the Manchester Acute Coronary Syndromes (MACS) and Troponin-only Manchester Acute Coronary Syndromes (T-MACS) rules for the prediction of acute myocardial infarction in patients presenting to the emergency department with chest pain.
abstract: BACKGROUND
  The Manchester Acute Coronary Syndromes (MACS) rule and the Troponin-only MACS (T-MACS) rule risk stratify patients with suspected acute coronary syndrome (ACS). This observational study sought to validate and compare the MACS and T-MACS rules for assessment of acute myocardial infarction (AMI).
  
  
  METHODS
  Prospectively collected data from twoEDs in Australia and New Zealand were analysed. Patients were assigned a probability of ACS based on the MACS and T-MACS rules, incorporating high-sensitivity troponin T, heart-type fatty acid-binding protein, ECG results and clinical symptoms. Patients were then deemed very low risk, low risk, intermediate or high risk if their MACS probability was less than 2%, between 2% and 5%, between 5% and 95% and greater than 95%, respectively. The primary endpoint was 30-day diagnosis of AMI. The secondary endpoint was 30-day major adverse cardiac event (MACE) including AMI, revascularisation or coronary stenosis (>70%). Sensitivity, specificity and predictive values were calculated to assess the accuracy of the MACS and T-MACS rules.
  
  
  RESULTS
  Of the 1244 patients, 114 (9.2%) were diagnosed with AMI and 163 (13.1%) with MACE. The MACS and T-MACS rules categorised 133 (10.7%) and 246 (19.8%) patients, respectively, as very low risk and potentially suitable for early discharge from the ED. There was one false negative case for both rules making sensitivity 99.1% (95.2%-100%).
  
  
  CONCLUSIONS
  MACS and T-MACS accurately risk stratify very low risk patients. The T-MACS rule would allow for more patients to be discharged early. The potential for missed MACE events means that further outpatient testing for coronary artery disease may be required for patients identified as very low risk.
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.|School of Medicine, University of Queensland, St Lucia, Queensland, Australia.|School of Public Health and Social Work, University of Technology, Brisbane, Australia.
authors.forename: Jaimi H
authors.initials: JH
authors.lastname: Greenslade
authors.affiliation: School of Medicine, University of Queensland, St Lucia, Queensland, Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Nayer
authors.affiliation: School of Medicine, University of Queensland, St Lucia, Queensland, Australia.|School of Public Health and Social Work, University of Technology, Brisbane, Australia.|Department of Cardiology, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
authors.forename: William
authors.initials: W
authors.lastname: Parsonage
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
authors.forename: Shaela
authors.initials: S
authors.lastname: Doig
authors.affiliation: Department of Medicine, University of Otago, Christchurch, New Zealand.
authors.forename: Joanna
authors.initials: J
authors.lastname: Young
authors.affiliation: Department of Medicine, University of Otago, Christchurch, New Zealand.
authors.forename: John W
authors.initials: JW
authors.lastname: Pickering
authors.affiliation: Department of Medicine, University of Otago, Christchurch, New Zealand.|Department of Emergency Medicine, Christchurch Hospital, Christchurch, New Zealand.
authors.forename: Martin
authors.initials: M
authors.lastname: Than
authors.affiliation: School of Medicine, University of Queensland, St Lucia, Queensland, Australia.|Department of Cardiology, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Hammett
authors.affiliation: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia.|School of Public Health and Social Work, University of Technology, Brisbane, Australia.|School of Medicine, University of Queensland, St Lucia, Queensland, Australia.
authors.forename: Louise
authors.initials: L
authors.lastname: Cullen
mesh_terms: D054058:Acute Coronary Syndrome / Q000145:classification* / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D001315:Australia; D002637:Chest Pain / Q000150:complications* / Q000175:diagnosis; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital / Q000458:organization & administration / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D011446:Prospective Studies; D014336:Troponin / Q000032:analysis* / Q000097:blood; D019210:Troponin I / Q000032:analysis / Q000097:blood; D020107:Troponin T / Q000032:analysis / Q000097:blood
chemical_list: D014336:Troponin; D019210:Troponin I; D020107:Troponin T
keywords: acute coronary syndrome; cardiac care; diagnosis