Clinical research study
Patients with Acute Coronary Syndrome and Normal High-sensitivity Troponin

https://doi.org/10.1016/j.amjmed.2011.07.032Get rights and content

Abstract

Background

Failure to identify patients with acute coronary syndrome (ACS) is a serious clinical problem. The incidence, characteristics, and outcome of ACS patients with normal high-sensitivity cardiac troponin T (hs-cTnT) levels at presentation are unknown.

Methods

In a prospective multicenter study, hs-cTnT was determined in a blinded fashion in 1181 consecutive patients presenting with acute chest pain to the emergency department. The final diagnosis of ACS was adjudicated by 2 independent cardiologists. Patients were followed for 12 months.

Results

ACS was the adjudicated diagnosis in 351 patients (30%), including 187 patients with acute myocardial infarction (AMI) and 164 patients with unstable angina (UA). At presentation, hs-cTnT was normal (<.014 ug/L) in 112 ACS patients (32%), including 11 patients (6%) with AMI and 101 patients (62%) with UA (P <.001). Multivariable analysis revealed previous statin treatment, younger age, preserved renal function, and the absence of ST deviation on the electrocardiogram as independently associated with normal hs-cTnT levels. Mortality rates in ACS patients with normal hs-cTnT level were 0.0% at 30 days, 0.0% at 90 days, and 2.0% (95% confidence interval, 0.5-7.9) at 360 days, which was significantly lower than in ACS patients with elevated hs-cTnT level at presentation (17.5% at 360 days, P <.001). Conversely, AMI rates at 360 days was higher in ACS patients with normal versus elevated hs-cTnT levels (P = .004).

Conclusion

Almost one third of ACS patients have normal hs-cTnT levels at presentation, mostly patients with UA. ACS patients with normal hs-cTnT have a very low mortality, but an increased rate of AMI during the subsequent 360 days.

Section snippets

Study Design and Population

The Advantageous Predictors of Acute Coronary Syndrome Evaluation (APACE) is an ongoing prospective international multicenter study designed and coordinated by the University Hospital Basel, Switzerland.13 Consecutive patients presenting to the ED with symptoms suggestive of AMI of <12 hours duration have been included, after informed consent, and were followed-up at regular intervals. Patients with terminal kidney failure requiring dialysis were excluded. The objective of the present study is

Results

The cohort analyzed in this study consisted of 1181 patients who had levels of hs-cTnT determined in a blinded fashion at presentation. The adjudicated final diagnosis was ACS in 351 patients (30%), including 112 patients with hs-cTnT within the normal range, and 239 patients with elevated hs-cTnT levels. An additional group of 484 patients who were adjudicated to have a noncardiac cause of acute chest pain and hs-cTnT levels within the normal range are reported (Figure).

Discussion

This prospective multicenter study evaluated the characteristics and outcome of patients with ACS as the cause of chest pain who had hs-cTnT, determined at presentation, below the 99th percentile. First, only a minority of patients with AMI had normal hs-cTnT concentration at presentation, whereas a large proportion of patients with UA had normal hs-cTnT concentration. Second, younger age, previous statin treatment, normal renal function, and the absence of ST deviation on ECG were

Acknowledgements

We are indebted to the patients who participated in the study and to the ED staff as well as the laboratory technicians, particularly Esther Garrido, Kirsten Hochholzer, and Fausta Chiaverio for their most valuable efforts, and we thank Kris Denhaerynck and PD Dr. Christian Schindler for expert statistical advice.

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    Funding: This study was supported by grants from the Swiss National Science Foundation (PP00B-102853), the Swiss Heart Foundation, Abbott, Roche, Siemens, and the Department of Internal Medicine, University Hospital Basel.

    Conflict of Interest: Dr Mueller reports receiving research grant support from Abbott, Brahms, Nanosphere Inc., Roche, and Siemens, consulting fees from Abbott, and lecture fees from Abbott, Biosite, Brahms, Roche, and Siemens. Dr Reichlin has received research grants from the University of Basel and the Department of Internal Medicine, University Hospital Basel as well as speaker honoraria from Brahms and Roche. Dr Meune was supported by a grant from the Freie Akademische Gesellschaft Basel (FAG).

    Authorship: The authors designed the study, gathered and analyzed the data, vouch for the data and analysis, wrote the paper, and decided to publish. The sponsors had no role in designing or conducting the study and no role in gathering or analyzing the data or writing the manuscript. All authors had access to the data and a role in writing the manuscript.

    These authors worked equally on the manuscript and should be both considered as first author.

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