P2673Challenging time limits: Using a single high-sensitive troponin I to rule-out acute myocardial infarction in early presenters

Abstract

Introduction According to ESC guidelines, an acute myocardial infarction (MI) can be excluded without serial troponin measurements in patients presenting with a single high-sensitive troponin below the 99th percentile and chest pain starting >6 hours prior to admission. However, it is unclear if single-testing of high-sensitive troponin can rule-out MI in early presenters. Purpose To investigate the diagnostic performance of a single value of high-sensitive cardiac troponin I (hs-cTnI) at presentation for ruling-out MI in patients presenting with chest pain to the Emergency Department irrespective of chest pain onset. Methods We conducted a substudy of preliminary data from the RACING-MI trial. We included patients presenting with chest pain suggestive of MI to the Emergency Department of a Regional Hospital. We used the Siemens hs-cTnI (Siemens Healthcare, TNIH, Limit of detection: 2.21 ng/L) and a diagnostic cut-off value <3 ng/L to rule-out MI at presentation. Two physicians independently adjudicated the final diagnosis based on all clinical information. Patients were stratified based on time from chest pain onset to hospital admission as very early (0–3 hours), early (3–6 hours) and late presenters (>6 hours). Results We included 989 patients with available hs-cTnI results at admission. MI was confirmed in 82 (8.3%) patients. Using hs-cTnI <3 ng/L as diagnostic cut-off value at presentation, 302 (30.5%) patients without MI were classified as rule-out. Overall, the negative predictive value (NPV) for MI was 100% (95% CI 98.7–100). Based on chest pain onset, 33.8% of patients were classified as very early, 12.8% as early, and 42.7% as late presenters, with 10.7% patients with unreported/unknown onset. NPV was 100% (95% CI 96.5–100) for very early, 100% (95% CI 88.3–100) for early and 100% (95% CI 97.3–100) for late presenters. Conclusions Using a single hs-cTnI value <3ng/L as diagnostic cut-off to rule-out MI seems to be safe and to allow rapid rule-out of MI in patients presenting with chest pain to the emergency department, even in very early presenters. ClinicalTrials.gov Identifier: NCT03634384. Acknowledgement/Funding Randers Regional Hospital, A.P Møller Foundation, Boserup Foundation, Korning Foundation, Højmosegård Grant, Siemens Healthcare (TNIH assays), etc.