Clinical research study
Implementation of High Sensitivity Cardiac Troponin T Measurement in the Emergency Department

https://doi.org/10.1016/j.amjmed.2010.07.015Get rights and content

Abstract

Background

We examined the diagnostic performance of high sensitivity cardiac troponin T (cTnThs) measurement and its ability to predict risk in unselected patients presenting to the emergency department with acute chest pain.

Methods

We conducted a retrospective analysis of 137 consecutive patients with chest pain (age range, 66 ± 16 years; 64% male). A final diagnosis of acute myocardial infarction was made using the “old” (cTnT fourth-generation assay, ≥0.04 μg/L) or the “new” cutpoint (cTnThs ≥0.014 μg/L).

Results

The adjudicated final diagnosis of acute myocardial infarction significantly increased from 20 to 35 patients (a 75% increase) and troponin-positive nonvascular cardiac chest pain from 10 to 30 (a 200% increase) using cTnThs. The number of patients with unstable angina or troponin-negative nonvascular cardiac chest pain significantly decreased (P <.05). Diagnostic performance of cTnThs levels at admission was significantly higher compared to cTnT levels (area under the curve [AUC] 0.85 vs AUC 0.70; P <.05). cTnThs levels below the detection limit (<0.003 μg/L) had a negative predictive value of 100% to exclude acute myocardial infarction. The event rate during 6 months of follow-up was low in patients with cTnThs levels <0.014 μg/L, while patients with cTnT levels ≥0.04 μg/L were at increased, and patients with cTnThs ≥0.014 μg/L and cTnT <0.04 μg/L at intermediate risk of death or recurrent myocardial infarction (P = .002). Risk was highest in chest pain patients with dynamic changes of cTnThs levels >30%.

Conclusion

The introduction of cTnThs assay displays an excellent diagnostic performance for the workup of patients with chest pain at the time of their initial presentation. Even small increases of cTnThs indicate increased risk for death or myocardial infarction during follow-up.

Section snippets

Methods

During the implementation of cTnThs measurement in routine practice (September 7 to 21, 2009), 137 consecutive patients with acute chest pain of possible coronary origin presented to the emergency department of the Nuremberg city hospital (50,000 attendances per year; the department caters to an urban population of approximately 1 million). The clinical presentation alone as judged by the emergency physician on duty qualified the patients to be diagnosed and treated according to the local chest

Results

During the 2-week period, 137 of 2340 patients presented to the emergency department with a chief complaint of chest pain. Seventy-one of the patients (53%) were admitted by a physician-based emergency medical service, 28 patients (20%) by the emergency medical service, and 38 patients (28%) presented by themselves. Thirty-six percent of patients presented within 2 hours after the beginning of chest pain, while 22%, 33%, and 20% of patients presented within 2 to 6 hours, 6 to 24 hours, and >24

Discussion

This study examined the diagnostic performance of a new, highly precise laboratory method to measure troponin T5 levels in unselected chest pain patients presenting to the emergency department. The main findings are as follows: first, the proportion of patients presenting with chest pain and abnormal cTnThs levels significantly increased by ∼170% compared to the conventional cTnT assay. The proportion of patients with a final diagnosis of unstable angina or cardiac chest pain without biomarker

Conclusion

The introduction of this cTnThs assay in routine clinical practice displays a rapid and excellent diagnostic performance for the work-up of chest pain patients at the time of initial presentation. Even small elevations of cTnThs levels are associated with a worse outcome during follow-up. Because minor increases of troponin levels that have not been detected by conventional assays in the past are seen in conditions such as heart failure, tachycardia, or strenuous exercise, disposition decisions

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    Funding: Supported by Roche Diagnostics, Mannheim, Germany, which provided free kits for high sensitivity cardiac troponin T measurement. The sponsor had no role in study design, data analysis, or interpretation.

    Conflict of Interest: Drs. Christ and Bertsch have received research support and speaker's honoraria from Roche Diagnostics. The other authors have no conflicts of interest to declare.

    Authorship: All authors meet criteria for authorship, had full access to the data, participated in the preparation of the manuscript, and accept responsibility for the scientific content of the manuscript.

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