Role of monitoring changes in sensitive cardiac troponin I assay results for early diagnosis of myocardial infarction and prediction of risk of adverse events.

Abstract

BACKGROUND:

We sought to determine the diagnostic accuracy of the cardiac troponin I (cTnI) VITROS(R) Troponin I-ES assay for early detection of acute myocardial infarction (AMI) and for risk prediction of adverse events in patients with symptoms of acute coronary syndrome (ACS).

METHODS:

cTnI was measured on admission and approximately 6 h postadmission in 381 patients. The 99th percentile cTnI concentration (0.034 microg/L) and change [delta (delta)] between admission and follow-up concentrations were evaluated in diagnostic sensitivity and specificity calculations. Risk of cardiac event or death within 60 days was evaluated by Cox proportional hazards regression.

RESULTS:

AMI occurred in 52 patients. Diagnostic sensitivities (95% CI) of admission and follow-up cTnIs for AMI were 69% (55%-81%) and 94% (84%-99%), respectively. The corresponding specificities (95% CI) were 78% (73%-82%) and 81% (77%-85%), and ROC curve areas were 0.82 vs 0.96 (P < 0.001). Deltas between admission and follow-up cTnI >30% had a sensitivity of 75% (95% CI 61%-86%) and a specificity of 91% (95% CI 87%-94%). During follow-up, 1 cardiac death, 2 noncardiac deaths, 52 AMIs, 6 coronary artery bypass grafts, and 43 percutanous coronary interventions occurred in 62 patients. A delta cTnI >30%, when added to either initial cTnI >0.034 microg/L or follow-up cTnI >0.034 microg/L, improved risk stratification for cardiac event or death (P < 0.001).

CONCLUSIONS:

Admission cTnI measured by the VITROS ES assay is a sensitive biomarker for detection of AMI. Utilizing >30% cTnI delta in addition to either the baseline or follow-up concentration improved both specificity and risk assessment in patients presenting with symptoms of ACS.

• Authors: Fred S Apple, Lesly A Pearce, Stephen W Smith, Jason M Kaczmarek, Maryann M Murakami
• Journal: Clinical chemistry (Clin Chem) Vol. 55 Issue 5 Pg. 930-7 (May 2009) ISSN: 1530-8561 [Electronic] England
• PMID: 19299542 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Biomarkers
• Troponin I

Topics

• Adult
• Aged
• Aged, 80 and over
• Biomarkers (blood)
• Humans
• Kaplan-Meier Estimate
• Middle Aged
• Myocardial Infarction (blood, diagnosis)
• Predictive Value of Tests
• Proportional Hazards Models
• Prospective Studies
• ROC Curve
• Sensitivity and Specificity
• Troponin I (blood)
• Young Adult