Does monitoring changes (>30% delta) in sensitive cardiac troponin I assay results improve early diagnosis of myocardial infarction and risk prediction in patients with symptoms of ACS?
Monitoring changes in sensitive cardiac troponin I (>30% delta) over 6 hours improves the specificity for diagnosing AMI and enhances 60-day risk stratification in patients with suspected ACS.
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 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 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.
Apple et al. (2009) studied this question.