Diagnostic Performance of a Combination Biomarker Algorithm for Rule-Out of Acute Myocardial Infarction at Time of Presentation to theEmergency Department, Using Heart-Type Fatty Acid-Binding Protein andHigh-Sensitivity Troponin T tests

Background: Chest pain of suspected cardiac origin is a common complaint for presentation at the emergency department; however only 10% to 13% of patients will have acute myocardial infarction (AMI). This study examined a decision support ‘rule-out’ algorithm to stratify risk of AMI in these patients. Methods: Five hundred and forty-eight patients with chest-pain of suspected cardiac origin were recruited. Blood samples were collected at presentation (t=0) and after 1, 2, 3, 6, 12 and 24 h. Serum troponin I, heart-type fatty acid bindingprotein (H-FABP), myoglobin, carbonic anhydrase III (CAIII), creatine phosphokinase MB isoenzyme (CKMB)and glycogen phosphorylase isoenzyme BB (GPBB) were measured using the Randox Cardiac Plus Array; Troponin T (cTnT), high sensitivity troponin T (hs-cTnT), high sensitivity CRP (hs-CRP), NT-pro-BNP, total cholesterol, and HDL were measured using a Modular P Analyser. Clinical and demographic information was recorded for each patient. Results: For biomarker analysis, STEMIs were excluded, leaving 360 patients at presentation (72 NSTEMI and 288 non-AMI) and 320 patients at 1 h (66 NSTEMI and 254 non-AMI). A rule-out algorithm was developed based onH-FABP and hs-cTnT. When the H-FABP hs-cTnT combination algorithm was applied to the data, 106 additional patients at presentation were identified as non-AMI compared to the standard ESC algorithm, 189/288 (65.6%) vs.83/288 (28.8%) (p<0.0005), respectively. Furthermore, the H-FABP hs-cTnT combination algorithm, identified 71% of non-AMI patients at 1 hour with no false negatives. Conclusion: Deployment of the H-FABP hs-cTnT combination algorithm at the emergency department could assist in the identification of non-AMI patients at presentation with the potential to reduce the number of hospital admissions by 106/288 (36.8%). Using the H-FABP hs-cTnT combination algorithm would have a significant impact on patient health ensuring that the appropriate care and efficient use of resources are directed to patients identified as high risk.