The use of very low concentrations of high sensitivity troponin T to rule out acute myocardial infarction using a single blood test.
Acad Emerg Med. 2016 May 14;
Authors: Body R, Mueller C, Giannitsis E, Christ M, Ordonez-Llanos J, de Filippi CR, Nowak R, Panteghini M, Jernberg T, Plebani M, Verschuren F, French JK, Christenson R, Weiser S, Bendig G, Dilba P, Lindahl B, TRAPID-AMI Investigators
BACKGROUND: Recent single center and retrospective studies suggest that acute myocardial infarction (AMI) could be immediately excluded without serial sampling in patients with initial high sensitivity troponin T (hs-cTnT) levels below the limit of detection (LoD) of the assay and no ECG ischemia.
OBJECTIVE: We aimed to determine the external validity of those findings in a multi-center study at 12 sites in 9 countries.
METHODS: TRAPID-AMI was a prospective diagnostic cohort study including patients with suspected cardiac chest pain within 6h of peak symptoms. Blood drawn on arrival was centrally tested for hs-cTnT (Roche, 99(th) percentile 14ng/L, LoD 5ng/L). All patients underwent serial troponin sampling over 4-14h. The primary outcome, prevalent AMI, was adjudicated based on sensitive troponin I (Siemens Ultra) levels. Major adverse cardiac events (MACE) including AMI, death or rehospitalisation for acute coronary syndrome with coronary revascularization were determined after 30 days.
RESULTS: We included 1,282 patients, of whom 213 (16.6%) had AMI and 231 (18.0%) developed MACE. Of 560 (43.7%) patients with initial hs-cTnT levels below the LoD, 4 (0.7%) had AMI. In total, 471 (36.7%) patients had both initial hs-cTnT levels below the LoD and no ECG ischemia. These patients had a 0.4% (n=2) probability of AMI, giving 99.1% (95% CI 96.7-99.9%) sensitivity and 99.6% (95% CI 98.5-100.0%) negative predictive value. The incidence of MACE in this group was 1.3% (95% CI 0.5-2.8%).
CONCLUSIONS: In the absence of ECG ischemia, the detection of very low concentrations of hs-cTnT at admission seems to allow rapid, safe exclusion of AMI in one-third of patients without serial sampling. This could be used alongside careful clinical assessment to help reduce unnecessary hospital admissions. This article is protected by copyright. All rights reserved.
PMID: 27178492 [PubMed - as supplied by publisher]