Outcomes associated with small changes in normal-range cardiac markers

McMullin, Nolan; Lindsell, Christopher J.; Lei, Lei; Mafi, John; Jois-Bilowich, Preeti; Anantharaman, Venkataraman; Pollack, Charles V.; Hollander, Judd E.; Gibler, W. Brian; Hoekestra, James W.; Diercks, Deborah; Peacock, W. Frank; for the EMCREG i*trACS Investigators,

doi:10.1016/j.ajem.2009.08.016

« Previous Next »American Journal of Emergency Medicine
Volume 29, Issue 2 , Pages 162-167, February 2011

Outcomes associated with small changes in normal-range cardiac markers

Nolan McMullin, MD
- The Cleveland Clinic, Cleveland, OH, USA
Christopher J. Lindsell, PhD
- The University of Cincinatti, Cincinatti, OH, USA
Lei Lei
- The Cleveland Clinic, Cleveland, OH, USA
John Mafi
- The Cleveland Clinic, Cleveland, OH, USA
Preeti Jois-Bilowich, MD
- University of Florida, Gainesvile, FL, USA
Venkataraman Anantharaman, MD
- Singapore General Hospital, Singapore
Charles V. Pollack Jr., MA, MD
- University of Pennsylvania, Philadelphia, PA, USA
Judd E. Hollander, MD
- University of Pennsylvania, Philadelphia, PA, USA
W. Brian Gibler, MD
- The University of Cincinatti, Cincinatti, OH, USA
James W. Hoekestra, MD
- Wake Forest University, Winston-Salem, NC, USA
Deborah Diercks, MD
- University of Sacramento, Davis, Davis, CA, USA
W. Frank Peacock, MD
- The Cleveland Clinic, Cleveland, OH, USA
- Corresponding author. Desk E-19, Emergency Department, The Cleveland Clinic, Cleveland, OH, 44195, USA. Tel.: +1 216 445 4546; fax: +1 216 445 4552.
for the EMCREG i*trACS Investigators

Received 10 June 2009; received in revised form 22 July 2009; accepted 18 August 2009. published online 10 March 2010.

Abstract

Introduction

Troponin concentrations rising above an institutional cutpoint are used to define acute myocardial necrosis, yet it is uncertain what outcomes are associated with fluctuations in troponin that do not exceed this level. We evaluate the association between troponin fluctuations below an institutional upper limit of normal and acute coronary syndrome (ACS).

Materials and methods

This was a post hoc analysis of the Internet tracking registry of ACS (i*trACS), which describes patients presenting to emergency departments (EDs) with suspected ACS across the spectrum of risk. Patients were included in this registry if they were at least 18 years old and had suspected ACS at the time of their ED visit. Inclusions in this analysis required that patients had at least 1 cardiac marker (creatine kinase-MB [CK-MB], troponin T, or troponin I) drawn twice within 6 hours of presentation, with both measures being below the institution's upper limit of normal. A marker change was defined as either an increase or decrease that exceeded 15% of the institutional upper limit of normal. Acute coronary syndrome was defined as a positive stress test, documented myocardial infarction, coronary revascularization, or death within 30 days of their ED admission.

Results

Of 17 713 patient visits, 2162 met inclusion and exclusion criteria. There were 1872 patient visits with 2 troponin results and 1312 with 2 CK-MB results. Patient visits with increasing troponin had increased odds of ACS compared with those with stable troponin levels (odds ratio, 3.6; 95% confidence interval, 1.4-9.2). Changing CK-MB and decreasing troponin were not associated with increased odds of ACS.