Abstract 18427: 1-Hour Algorithm Based on High-Sensitivity Troponin I to Diagnose Type 1 Acute Myocardial Infarction
Background: There is a clinical need for early and accurate diagnosis of acute myocardial infarction (AMI). According to current ESC guidelines, the diagnosis of non-ST-elevation AMI is based on serial troponin measurements. We aimed to challenge these algorithms diagnosing Type 1 AMI with a high-sensitivity troponin I (hs-TnI) and tested (1) different absolute hs-TnI changes after 1 hour and (2) additional use of ECG and echocardiography.
Methods: 1,216 patients presenting at the chest pain unit with suspected AMI were included. ST-elevation AMI patients were excluded. We distinguished Type 1 and Type 2 AMI according to the universal definition. Hs-TnI was measured directly at admission and after 1 hour. We investigated different absolute changes of hs-TnI after 1 hour and additional application of a pathological ECG or echocardiography to diagnose Type 1 AMI.
Results: The mean age of the study population was 64 years. 137 of all patients had the final diagnosis of Type 1 AMI.
(1) A 1-hour hs-TnI change of 6 ng/L, as recommended in current guidelines, resulted in a PPV of 56.0% with 103 true and 81 false positive patients for the diagnosis of Type 1 AMI. With rising hs-TnI changes, the PPV increased and less patients were classified being false positive. A cutoff of 12 ng/L translated to a PPV of 78.9% and a sensitivity of 68.3 (86 true and only 23 false positive patients).
(2) After additional application of a pathological ECG or echocardiography, the PPV increased, while the sensitivity was reduced. At a cutoff concentration of 12 ng/L the PPV was 89.9% and the sensitivity was 54.4%. This translated into 62 true and 7 false positive patients.
Conclusion: The diagnosis of AMI based on hs-TnI is challenging. A hs-TnI change of 12 ng/L after 1 hour may facilitate rapid rule-in of patients, while ECG and echocardiography are important additional diagnostic tools.
Author Disclosures: J.T. Neumann: None. N.A. Sörensen: None. F. Ojeda: None. T. Schwemer: None. T. Zeller: None. R. Schnabel: None. M. Karakas: None. T. Renne: None. S. Blankenberg: Honoraria; Modest; Abbott Diagnostics, Siemens, Thermo Fisher, Roche Diagnostics. Consultant/Advisory Board; Modest; Thermo Fisher. D. Westermann: None.
- © 2016 by American Heart Association, Inc.