A 3-hour diagnostic algorithm for non-ST-elevation myocardial infarction using high-sensitivity cardiac troponin T in unselected older patients presenting to the emergency department.

Abstract

OBJECTIVES:

To determine if an algorithm implementing a serial high-sensitive cardiac troponin T (hs-cTnT) measurement at presentation (0 h) and at 3 hours after presentation (3h) is helpful for early diagnosis of non-ST-elevation myocardial infarction (NSTEMI) in older patients.

DESIGN:

Prospective observational cohort study.

SETTING:

An emergency department (ED) of a city hospital covering a population of approximately 1 million in Germany.

PARTICIPANTS:

A total of 332 consecutive unselected patients were recruited, of whom 25 had one or more of the prespecified exclusion criteria and 1 had a missing hs-cTnT at 3h, resulting in a final population of 306 patients.

MEASUREMENTS:

In addition to clinical examination, hs-cTnT was measured at 0 h and 3 h. The final diagnosis of NSTEMI was adjudicated by two independent consultants and an algorithm for rule-in and rule-out of NSTEMI was developed using classification and regression tree analysis. All patients were followed-up for cardiovascular outcome within 12 months.

RESULTS:

Among 306 patients (mean age 81 ± 6 years), 38 (12%) patients had NSTEMI. Accuracy to diagnose NSTEMI was significantly higher for hs-cTnT measurements at 3 h versus 0 h (area under the receiver operating characteristic curve [AUC] 0.88 vs. 0.82, P = .0038) and for absolute versus relative hs-cTnT delta changes (AUC 0.89 versus 0.69, P < .001). A diagnostic algorithm using hs-cTnT values at presentation and absolute delta changes values ruled-in NSTEMI in 23% and ruled-out NSTEMI in 35% of patients. For patients neither fulfilling the rule-in nor the rule-out criteria, an observational zone was established. Cumulative 1-year survival was 79.4%, 88.5%, and 99.1% in patients classified as rule-in, observational zone, and rule-out, respectively.

CONCLUSION:

In older patients, serial hs-cTnT measurements and absolute delta-changes at 3h were valuable for early diagnosis of NSTEMI. An algorithm ruled-in NSTEMI in one quarter of patients with high risk and ruled-out NSTEMI in one-third with low risk.

• Authors: Philipp Bahrmann, Michael Christ, Anke Bahrmann, Harald Rittger, Hans Jürgen Heppner, Stephan Achenbach, Thomas Bertsch, Cornel C Sieber
• Journal: Journal of the American Medical Directors Association (J Am Med Dir Assoc) Vol. 14 Issue 6 Pg. 409-16 (Jun 2013) ISSN: 1538-9375 [Electronic] United States
• PMID: 23375478 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 American Medical Directors Association, Inc. Published by Elsevier Inc. All rights reserved.

Chemical References

• Troponin T

Topics

• Aged, 80 and over
• Algorithms
• Decision Support Techniques
• Early Diagnosis
• Emergency Service, Hospital
• Female
• Humans
• Male
• Myocardial Infarction (blood, diagnosis)
• Predictive Value of Tests
• Prospective Studies
• Sensitivity and Specificity
• Time Factors
• Troponin T (blood)