scholarly journals Diagnostic and Prognostic Information Provided by a High Sensitivity Assay for Cardiac Troponin T

2010 ◽  
Vol 29 (4) ◽  
pp. 274-281 ◽  
Author(s):  
Jochen Jarausch

Diagnostic and Prognostic Information Provided by a High Sensitivity Assay for Cardiac Troponin TCardiac troponins (cTns) are the preferred biomarkers for the diagnosis of acute myocardial infarction, assessment of risk and prognosis, and for determination of antithrombotic and revascularization strategy in patients with acute coronary syndromes. The implementation of high sensitivity cTn assays into the clinical routine has increased the number of patients diagnosed with myocardial infarction. In addition, the number of patients with elevated cTn levels that cannot be explained by acute ischemic injury was increased, which is observed in patients with chronic heart disease and other nonischemic cardiac injury or in patients with impaired renal function. The new definition of myocardial infarction provides support for the interpretation of elevated cTn measured with high sensitivity cTn assays in patients with suspected acute coronary syndrome. This review will summarize clinical studies with the recently introduced high sensitivity cTnT assay (TnT hs) with reference to recent experience with high sensitivity cTn assays in general.

2010 ◽  
Vol 56 (4) ◽  
pp. 642-650 ◽  
Author(s):  
Evangelos Giannitsis ◽  
Meike Becker ◽  
Kerstin Kurz ◽  
Georg Hess ◽  
Dietmar Zdunek ◽  
...  

Abstract Background: We sought to determine the diagnostic performance of the new high-sensitivity cardiac troponin T (hs-cTnT) assay for early detection of non–ST-segment myocardial infarction (NSTEMI) in patients with acute coronary syndrome. Methods: We enrolled patients with retrospectively confirmed unstable angina or NSTEMI and an initially negative cTnT concentration and compared the performance of baseline concentrations and serial changes in concentration within 3 and 6 h. Percentage change criteria included ≥20% δ change and ROC-optimized value. Results: Based on the standard fourth-generation cTnT result of ≥0.03 μg/L, an evolving NSTEMI was diagnosed in 26 patients, and 31 patients were classified as having unstable angina. With the use of the hs-cTnT assay at the 99th-percentile cutoff, the percentage of NSTEMI cases detected increased gradually from 61.5% on presentation to 100% within 6 h, and the overall number of MI diagnoses increased by 34.6% (35 vs 26 cases). A δ change ≥20% or ≥ROC-optimized value of >117% within 3 h or ≥243% within 6 h yielded a specificity of 100% at sensitivities between 69% and 76%. The standard cTnT at the 99th percentile was less sensitive than hs-cTnT for early diagnosis of MI on presentation, and follow-up samples obtained within the initial 3 h demonstrated very low specificity of cTnT compared with hs-cTnT. Conclusions: The high-sensitivity cTnT assay increases the number of NSTEMI diagnoses and enables earlier detection of evolving NSTEMI. A doubling of the hs-cTnT concentration within 3 h in the presence of a second concentration ≥99th percentile is associated with a positive predictive value of 100% and a negative predictive value of 88%.


2011 ◽  
Vol 57 (9) ◽  
pp. 1318-1326 ◽  
Author(s):  
Willibald Hochholzer ◽  
Tobias Reichlin ◽  
Raphael Twerenbold ◽  
Claudia Stelzig ◽  
Kirsten Hochholzer ◽  
...  

BACKGROUND High-sensitivity cardiac troponin assays have better analytical precision and sensitivity than earlier-generation assays when measuring cardiac troponin at low concentrations. We evaluated whether use of a high-sensitivity assay could further improve risk stratification compared with a standard cardiac troponin assay. METHODS We enrolled consecutive patients presenting with acute chest pain, 30% of whom were diagnosed with acute coronary syndrome. Blood samples were drawn at the time of presentation. We measured cardiac troponin T with a standard fourth-generation assay (cTnT) and a high-sensitivity assay (hs-cTnT) (both Roche Diagnostics) and followed the patients for 24 months. RESULTS Of the 1159 patients, 76 died and 42 developed an acute myocardial infarction (AMI). Prognostic accuracy of hs-cTnT for death was significantly higher [area under ROC curve (AUC) 0.79, 95% CI 0.74–0.84] than that of cTnT (AUC 0.69, 95% CI 0.62–0.76; P < 0.001). After adjustment for Thrombolysis in Myocardial Infarction (TIMI) risk score (that included the cTnT assay result), hs-cTnT above the 99th percentile (0.014 μg/L) was associated with a hazard ratio for death of 2.60 (95% CI 1.42–4.74). Addition of hs-cTnT to the risk score improved the reclassification of patients (net reclassification improvement 0.91; 95% CI 0.67–1.14; P < 0.001). Subgroup analyses showed that this effect resulted from the better classification of patients without AMI at time of testing. hs-cTnT outperformed cTnT in the prediction of AMI during follow-up (P=0.02), but was not independently predictive for this endpoint. CONCLUSIONS Concentrations of hs-cTnT >0.014 μg/L improve the prediction of death but not subsequent AMI in unselected patients presenting with acute chest pain.


Author(s):  
Paul Simpson ◽  
Rosy Tirimacco ◽  
Penelope Cowley ◽  
May Siew ◽  
Narelle Berry ◽  
...  

Background The management of patients presenting with symptoms suggestive of acute coronary syndrome is a significant challenge for clinicians. Guidelines for the diagnosis of acute myocardial infarction require a rise and/or fall of cardiac troponin, along with other criteria. Knowing what constitutes a significant delta change from baseline is still unclear and the literature is varied. Methods We compared three methods for determining cardiac troponin delta changes (relative, absolute and z-scores) for detecting acute myocardial infarction in 806 patients presenting to an emergency department with symptoms suggestive of acute coronary syndrome. Blood specimens were collected at admission and 2, 3, 4 and 6 h postadmission and tested on the Roche Elecsys high-sensitivity troponin T assay. Results A positive diagnosis for acute myocardial infarction was found in 39 (4.8%) patients. ROC AUC showed better performance for the absolute and z-score delta change (0.959–0.988 and 0.956–0.988, respectively) compared with relative delta change (0.921–0.960) at all time points in the diagnosis of acute myocardial infarction. Optimal timing for the second sample was at 4–6 h postadmission. Conclusions Although not statistically significant, the results show a trend of absolute and z-score delta change performing better than relative delta change for the diagnosis of acute myocardial infarction. The z-score approach allows for a single cut-off value across multiple high-sensitivity assays which could be useful in the clinical setting. Our study also highlighted the importance of interpreting cardiac troponin changes in the clinical context with a combination of the patient’s clinical history and electrocardiogram.


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