title: The Manchester Acute Coronary Syndromes (MACS) decision rule: validation with a new automated assay for heart-type fatty acid binding protein.
abstract: OBJECTIVE
  The Manchester Acute Coronary Syndromes (MACS) decision rule may enable acute coronary syndromes to be immediately 'ruled in' or 'ruled out' in the emergency department. The rule incorporates heart-type fatty acid binding protein (h-FABP) and high sensitivity troponin T levels. The rule was previously validated using a semiautomated h-FABP assay that was not practical for clinical implementation. We aimed to validate the rule with an automated h-FABP assay that could be used clinically.
  
  
  METHODS
  In this prospective diagnostic cohort study we included patients presenting to the emergency department with suspected cardiac chest pain. Serum drawn on arrival was tested for h-FABP using an automated immunoturbidimetric assay (Randox) and high sensitivity troponin T (Roche). The primary outcome, a diagnosis of acute myocardial infarction (AMI), was adjudicated based on 12 h troponin testing. A secondary outcome, major adverse cardiac events (MACE; death, AMI, revascularisation or new coronary stenosis), was determined at 30 days.
  
  
  RESULTS
  Of the 456 patients included, 78 (17.1%) had AMI and 97 (21.3%) developed MACE. Using the automated h-FABP assay, the MACS rule had the same C-statistic for MACE as the original rule (0.91; 95% CI 0.88 to 0.92). 18.9% of patients were identified as 'very low risk' and thus eligible for immediate discharge with no missed AMIs and a 2.3% incidence of MACE (n=2, both coronary stenoses). 11.1% of patients were classed as 'high-risk' and had a 92.0% incidence of MACE.
  
  
  CONCLUSIONS
  Our findings validate the performance of a refined MACS rule incorporating an automated h-FABP assay, facilitating use in clinical settings. The effectiveness of this refined rule should be verified in an interventional trial prior to implementation.
  
  
  BACKGROUND
  UK CRN 8376.
authors.affiliation: The University of Manchester, Manchester, UK Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Body
authors.affiliation: Stockport NHS Foundation Trust, Manchester, UK.
authors.forename: Gillian
authors.initials: G
authors.lastname: Burrows
authors.affiliation: Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK Manchester Metropolitan University, Manchester, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Carley
authors.affiliation: Stockport NHS Foundation Trust, Manchester, UK.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Lewis
mesh_terms: D054058:Acute Coronary Syndrome / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002637:Chest Pain / Q000175:diagnosis; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood; D020107:Troponin T / Q000097:blood
chemical_list: D015415:Biomarkers; C493408:FABP3 protein, human; D000074026:Fatty Acid Binding Protein 3; D050556:Fatty Acid-Binding Proteins; D019210:Troponin I; D020107:Troponin T
keywords: acute coronary syndrome; cardiac care, diagnosis; diagnosis