Abstract 154: Limitation of Troponin T In Identifying the Cause of Out-of-hospital Cardiac Arrest

Abstract

Introduction: High Sense-Troponin T (HS-TnT) is a key determinant for presence or absence of acute MI in chest pain patients (pts). Its value for acute MI diagnosis in pts with out-of-hospital cardiac arrest (OHCA) needs assessment because myocardial ischemia may be the cause but also a consequence of cardiac arrest causing global ischemia during no and low flow periods. Methods: Data were prospectively collected. From pts included in the ARREST registry who survived OHCA to discharge with VF as initial rhythm, the cause of OHCA and peak HS-TnT were analyzed. Cause of OHCA was determined independently by researchers, from history, admission and serial ECG, coronary angiography (CAG), cardiac imaging and genetics as available and indicated, without using HS-TnT information. MI diagnosis was made according to the 4 th universal definition of MI: type 1 MI (thrombotic STEMI/NSTEMI), type 2 MI (supply/demand imbalance) and no MI (short transient ECG changes and all non-ischemic causes). Results: From 2012 till 2018 in the study region 373 OHCA pts met the inclusion criteria and had a known peak HS-TnT. Of these, Type 1 MI was present in 109 STEMI and 39 NSTEMI pts, type 2 MI in 116 pts and no MI in 109 pts. No significant coronary stenosis or normal CAG was present in 81 pts: 11/106 (10%) with type 2 MI and 70/109 (64%) without MI. HS-TnT exceeded the conventional diagnostic threshold of 4 times upper limit of normal (4x14ng/L = 56 ng/L) in 99%, 95%, 95% and 89% of pts, respectively. Median peak HS-TnT levels in STEMI, NSTEMI, Type 2 and no AMI pts was 1890 ng/L, 480 ng/L, 300 ng/L and 261 ng/L, respectively. (Figure) Area Under the ROC-Curve of HS-TnT values to differentiate between type 1 NSTEMI and type 2 AMI was 0.649, between type 1 NSTEMI and no MI 0.684 and between type 2 MI and no AMI 0.555. Conclusion: Exclusion of diagnosis of MI in OHCA pts cannot be made with HS-TnT, nor a distinction between NSTEMI, type 2 MI and no AMI. Based on HS-TnT many OHCA pts without ischemic cause would classify as NSTEMI.