Evaluation of Dual Marker Approach Using Heart-Type Fatty Acid Binding Protein and High Sensitivity Troponin-I as an Alternative to Serial Sampling for Diagnosis of Acute Myocardial Infarction.

Objective: An early rule in (high specificity and high PPV) and early rule out (high sensitivity and high NPV) is essential for diagnosing acute myocardial infarction (AMI) to provide better utilization of resources, cost-effectiveness, and to reduce mortality.

Methods: Consecutive chest pain patients (n=80) with symptoms indicative of coronary artery disease reported to the emergency room within 6 hours after onset of symptoms. An alternate Dual Marker Approach (DMA; both Heart-type Fatty Acid Binding Protein (H-FABP) and High sensitive Troponin-I (hsTnI) at 0 h) was compared to the Double Sampling approach (DSA; hsTnI at 0 h and 3 h (ESC guidelines)).

Results: If both biomarkers were increased (n=17; 77.5%: 11 STEMI and 6 NSTEMI) above their respective cut-off value (HFABP 6.3 ng/mL and hsTnI 20.24 ng/L) at presentation, AMI ensued (100% PPV). Also, if both the markers were below their respective cut-offs at presentation, AMI was safely ruled out (n=41; with only 1 false negative). However, among the patients with either of these markers above their respective cut-off at presentation (n=22), DSA was required to find remaining AMI cases (n=4). Overall, DMA stands best for rule out (sensitivity 95.5%, NPV 97.6%) while DSA is superior for rule in (98.2% specificity, 95.2% PPV).

Conclusion: With the use of the proposed DMA, 58/80 (72.5%) patients with acute chest pain were reliably ruled in/ruled out for AMI at the presentation itself, while the remaining patients still required serial monitoring (DSA) for confirmation.