Use of conventional cardiac troponin assay for diagnosis of non-ST-elevation myocardial infarction: 'The Ottawa Troponin Pathway'

Venkatesh Thiruganasambandamoorthy; Ian G Stiell; Hina Chaudry; Muhammad Mukarram; Ronald A Booth; Cristian Toarta; Guy Hebert; Robert S Beanlands; George A Wells; Marie-Joe Nemnom; Monica Taljaard

doi:10.1371/journal.pone.0226892

Use of conventional cardiac troponin assay for diagnosis of non-ST-elevation myocardial infarction: 'The Ottawa Troponin Pathway'

PLoS One. 2020 Jan 10;15(1):e0226892. doi: 10.1371/journal.pone.0226892. eCollection 2020.

Authors

Venkatesh Thiruganasambandamoorthy^{1

2

3}, Ian G Stiell^{1

2

3}, Hina Chaudry², Muhammad Mukarram², Ronald A Booth⁴, Cristian Toarta^{3

5}, Guy Hebert¹, Robert S Beanlands⁶, George A Wells³, Marie-Joe Nemnom², Monica Taljaard^{2

3}

Affiliations

¹ Department of Emergency Medicine, University of Ottawa, Ottawa, ON, Canada.
² Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, ON, Canada.
³ School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada.
⁴ Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, ON, Canada.
⁵ Division of Emergency Medicine, University of Toronto, Toronto, ON, Canada.
⁶ Division of Cardiology, University of Ottawa, Ottawa, ON, Canada.

Abstract

Background: Serial conventional cardiac troponin (cTn) measurements 6-9 hours apart are recommended for non-ST-elevation MI (NSTEMI) diagnosis. We sought to develop a pathway with 3-hour changes for major adverse cardiac event (MACE) identification and assess the added value of the HEART [History, Electrocardiogram (ECG), Age, Risk factors, Troponin] score to the pathway.

Methods: We prospectively enrolled adults with NSTEMI symptoms at two-large emergency departments (EDs) over 32-months. Patients with STEMI, unstable angina and one cTn were excluded. We collected baseline characteristics, Siemens Vista conventional cTnI at 0, 3 or 6-hours after ED presentation; HEART score predictors; disposition and ED length of stay (LOS). Adjudicated primary outcome was 15-day MACE (acute MI, revascularization, or death due to cardiac ischemia/unknown cause). We analyzed multiples of 99th percentile cut-off cTnI values (45, 100 and 250ng/L).

Results: 1,683 patients (mean age 64.7 years; 55.3% female; median LOS 7-hours; 88 patients with 15-day MACE) were included. 1,346 (80.0%) patients with both cTnI≤45 ng/L; and 155 (9.2%) of the 213 patients with one value≥100ng/L but both<250ng/L or ≤20% change did not suffer MACE. Among 124 patients (7.4%) with one of the two values>45ng/L but<100ng/L based on 3 or 6-hour cTnI, one patient with absolute change<10ng/L and 6 of the 19 patients with≥20ng/L were diagnosed with NSTEMI (patients with Δ10-19ng/L between first and second cTnI had third one at 6-hours). Based on the results, we developed the Ottawa Troponin Pathway (OTP) with a 98.9% sensitivity (95% CI 93.8-100%) and 94.6% specificity (95% CI 93.3-95.6%). Addition of the HEART score improved the sensitivity to 100% (95% CI 95.9-100%) and decreased the specificity to 26.5% (95% CI 24.3-28.7%).

Conclusion: The OTP with conventional cTnI 3-hours apart, should lead to better NSTEMI identification particularly those with values >99th percentile, standardize management and reduce the ED LOS.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aged
Cohort Studies
Female
Humans
Male
Middle Aged
Myocardium / metabolism*
Non-ST Elevated Myocardial Infarction / diagnosis*
Non-ST Elevated Myocardial Infarction / metabolism*
Prognosis
Troponin I / metabolism*

Substances

Troponin I

Grants and funding

The study was funded by the Innovation Fund for Academic Health Sciences Centres of Ontario through The Ottawa Hospital Academic Medical Organization (TOHAMO). Initials of the authors who received the award: VT, IGS, RAB, GH, RSB, GAW, MT. Grant Number: Not applicable. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.