Absolute and relative changes (delta) in troponin I for early diagnosis of myocardial infarction: Results of a prospective multicenter trial

Alan B Storrow; Richard M Nowak; Deborah B Diercks; Adam J Singer; Alan H B Wu; Erik Kulstad; Frank LoVecchio; Christian Fromm; Gary Headden; Tracie Potis; Christopher J Hogan; Jon W Schrock; Daniel P Zelinski; Marna R Greenberg; Robert H Christenson; James C Ritchie; Janna S Chamberlin; Kurtis R Bray; Daniel W Rhodes; Deirdre Trainor; Paula C Southwick

doi:10.1016/j.clinbiochem.2014.09.012

Absolute and relative changes (delta) in troponin I for early diagnosis of myocardial infarction: Results of a prospective multicenter trial

Clin Biochem. 2015 Mar;48(4-5):260-7. doi: 10.1016/j.clinbiochem.2014.09.012. Epub 2014 Sep 28.

Authors

Alan B Storrow¹, Richard M Nowak², Deborah B Diercks³, Adam J Singer⁴, Alan H B Wu⁵, Erik Kulstad⁶, Frank LoVecchio⁷, Christian Fromm⁸, Gary Headden⁹, Tracie Potis¹⁰, Christopher J Hogan¹¹, Jon W Schrock¹², Daniel P Zelinski¹³, Marna R Greenberg¹⁴, Robert H Christenson¹⁵, James C Ritchie¹⁶, Janna S Chamberlin¹⁷, Kurtis R Bray¹⁷, Daniel W Rhodes¹⁷, Deirdre Trainor¹⁷, Paula C Southwick¹⁷

Affiliations

¹ Dept. of Emergency Medicine, Vanderbilt University Medical Center, Nashville, TN, USA. Electronic address: [email protected].
² Dept. of Emergency Medicine, Henry Ford Health System, Detroit, MI, USA.
³ Dept. of Emergency Medicine, University of California Davis, Sacramento, CA, USA.
⁴ Dept. of Emergency Medicine, State University of New York at Stony Brook, Stony Brook, NY, USA.
⁵ Clinical Chemistry Laboratory, San Francisco General Hospital, University of California, San Francisco, CA, USA.
⁶ Dept. of Emergency Medicine, Advocate Christ Medical Center, Oak Lawn, IL, USA.
⁷ Dept. of Emergency Medicine, Maricopa Medical Center, Phoenix, AZ, USA.
⁸ Dept. of Emergency Medicine, Maimonides Medical Center, Brooklyn, NY, USA.
⁹ Chest Pain Center, Medical University of South Carolina, Charleston, SC, USA.
¹⁰ Dept. of Emergency Medicine, Covenant Medical Center, Saginaw, MI, USA.
¹¹ Dept. of Emergency Medicine, Virginia Commonwealth University Medical Center, Richmond, VA, USA.
¹² Dept. of Emergency Medicine, Case Western Reserve University School of Medicine, MetroHealth Medical Center, Cleveland, OH, USA.
¹³ Dept. of Emergency Medicine, The Ohio State University Medical Center, Columbus, OH, USA.
¹⁴ Dept. of Emergency Medicine, Lehigh Valley Health Network, Allentown, PA, USA.
¹⁵ Dept. of Pathology, University of Maryland Medical Center, Baltimore, MD, USA.
¹⁶ Dept. of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA.
¹⁷ Dept. of Clinical Research, Beckman Coulter, Inc., Carlsbad, CA, USA.

PMID: 25261587
DOI: 10.1016/j.clinbiochem.2014.09.012

Abstract

Objectives: We investigated absolute and relative cardiac troponin I (TnI) delta changes, optimal sampling protocols, and decision thresholds for early diagnosis of myocardial infarction (MI). Serial cardiac biomarker values demonstrating a rise and/or fall define MI diagnosis; however the magnitude of change, timing, and diagnostic accuracy of absolute versus relative (percentage) deltas remains unsettled.

Methods: We prospectively measured TnI (AccuTnI+3™, Beckman Coulter) at serial time intervals in 1929 subjects with chest pain or equivalent symptoms of acute coronary syndrome at 14 medical centers. Diagnosis was adjudicated by an independent central committee.

Results: Elevated TnI above a threshold of 0.03ng/mL demonstrated significant diagnostic efficacy (AUC 0.96). For patients with TnI<0.03ng/mL and symptom onset≥8h, 99.1% (NPV) were diagnosed with conditions other than MI. Absolute delta performed significantly better than relative delta at 1-3h (AUC 0.84 vs 0.69), 3-6h (0.85 vs 0.73), and 6-9h (0.91 vs 0.79). Current recommendations propose ≥20% delta within 3-6h; however, results were optimized using an absolute delta of 0.01 or 0.02ng/mL. Sensitivity results for absolute delta at 1-3h and 3-6h (75.8%, 78.3%) were superior to relative delta (48.0%, 61.3%). NPV (rule out) was 99.6% when baseline TnI<0.03ng/mL and absolute delta TnI<0.01ng/mL.

Conclusions: Absolute delta performed significantly better than relative delta at all time intervals. Baseline TnI and absolute delta may be used in conjunction to estimate probability of MI. Consensus recommendations are supported for sampling on admission and 3h later, repeated at 6h in patients when clinical suspicion remains high.

Keywords: Acute coronary syndrome; Biomarker; Chest pain diagnosis; Myocardial infarction; Troponin.

Publication types

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

MeSH terms

Biomarkers / blood
Early Diagnosis
Female
Humans
Male
Myocardial Infarction / blood*
Myocardial Infarction / diagnosis*
Prospective Studies
Time Factors
Troponin I / blood*

Substances

Biomarkers
Troponin I