title: Heart Fatty Acid Binding Protein and cardiac troponin: development of an optimal rule-out strategy for acute myocardial infarction.
abstract: Improved ability to rapidly rule-out Acute Myocardial Infarction (AMI) in patients presenting with chest pain will promote decongestion of the Emergency Department (ED) and reduce unnecessary hospital admissions. We assessed a new commercial Heart Fatty Acid Binding Protein (H-FABP) assay for additional diagnostic value when combined with cardiac troponin (using a high sensitivity assay).
  
  
  
  H-FABP and high-sensitivity troponins I (hs-cTnI) and T (hs-cTnT) were measured in samples taken on-presentation from patients, attending the ED, with symptoms triggering investigation for possible acute coronary syndrome. The optimal combination of H-FABP with each hs-cTn was defined as that which maximized the proportion of patients with a negative test (low-risk) whilst maintaining at least 99 % sensitivity for AMI. A negative test comprised both H-FABP and hs-cTn below the chosen threshold in the absence of ischemic changes on the ECG.
  
  
  
  One thousand seventy-nine patients were recruited including 248 with AMI. H-FABP < 4.3 ng/mL plus hs-cTnI < 10.0 ng/L together with a negative ECG maintained >99 % sensitivity for AMI whilst classifying 40.9 % of patients as low-risk. The combination of H-FABP < 3.9 ng/mL and hs-cTnT < 7.6 ng/L with a negative ECG maintained the same sensitivity whilst classifying 32.1 % of patients as low risk.
  
  
  
  In patients requiring rule-out of AMI, the addition of H-FABP to hs-cTn at presentation (in the absence of new ischaemic ECG findings) may accelerate clinical diagnostic decision making by identifying up to 40 % of such patients as low-risk for AMI on the basis of blood tests performed on presentation. If implemented this has the potential to significantly accelerate triaging of patients for early discharge from the ED.
authors: University of Otago, Christchurch, New Zealand.|Lipid and Diabetes Research Group, Christchurch, New Zealand.
authors: Joanna M
authors: JM
authors: Young
authors: University of Otago, Christchurch, New Zealand.|Emergency Department, Christchurch Hospital, Christchurch, New Zealand.
authors: John W
authors: JW
authors: Pickering
authors: University of Otago, Christchurch, New Zealand.|Canterbury Health Laboratories, Christchurch, New Zealand.
authors: Peter M
authors: PM
authors: George
authors: Cardiology Department, Christchurch Hospital, Christchurch, New Zealand.
authors: Sally J
authors: SJ
authors: Aldous
authors: Canterbury Health Laboratories, Christchurch, New Zealand.
authors: John
authors: J
authors: Wallace
authors: University of Otago, Christchurch, New Zealand.
authors: Chris M
authors: CM
authors: Frampton
authors: University of Otago, Christchurch, New Zealand.|Cardiology Department, Christchurch Hospital, Christchurch, New Zealand.
authors: Richard W
authors: RW
authors: Troughton
authors: University of Otago, Christchurch, New Zealand.
authors: Mark A
authors: MA
authors: Richards
authors: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.|School of Public Health, Queensland University of Technology, Brisbane, Queensland, Australia.
authors: Jaimi H
authors: JH
authors: Greenslade
authors: Department of Emergency Medicine, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia.|School of Medicine, The University of Queensland, Brisbane, Queensland, Australia.|School of Public Health, Queensland University of Technology, Brisbane, Queensland, Australia.
authors: Louise
authors: L
authors: Cullen
authors: Emergency Department, Christchurch Hospital, Christchurch, New Zealand. martin.than@xtra.co.nz.
authors: Martin P
authors: MP
authors: Than
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D002637:Chest Pain / Q000209:etiology; D004562:Electrocardiography; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D050556:Fatty Acid-Binding Proteins / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000150:complications / Q000175:diagnosis*; D011446:Prospective Studies; D012372:ROC Curve; D019210:Troponin I / Q000097:blood*; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D050556:Fatty Acid-Binding Proteins; D019210:Troponin I; D020107:Troponin T
keywords: Accelerated diagnostic pathway; Acute myocardial infarction; Heart Fatty Acid Binding Protein; High-sensitivity troponin; Multi-marker strategy; Rule-out strategy