Early Diagnosis of Acute Myocardial Infarction in the Elderly Using More Sensitive Cardiac Troponin Assays
What is the diagnostic accuracy of high-sensitivity troponin (cTn) assays in elderly patients with chest pain?
The authors evaluated three investigational sensitive cTn assays (Roche high-sensitive cTnT [hs-cTnT], Siemens cTnI-Ultra, and Abbott-Architect cTnI) and the standard assay (Roche cTnT) in 1,098 patients in a multicenter study. The investigators reported the diagnostic accuracy of the assay in 406 patients who were older than 70 years of age. Final diagnosis was adjudicated by two independent cardiologists.
Acute myocardial infarction (AMI) was the adjudicated final diagnosis in 24% of elderly patients. Among elderly patients without AMI, an elevation in cTn level above the 99th percentile was detected in 51% with Roche hs-cTnT, in 17% with Siemens TnI-Ultra, and in 13% with Abbott-Architect cTnI assay. All of the three sensitive assays had high diagnostic accuracy compared with the traditional assay (area under the receiver operating characteristic [ROC] curve [AUC] for Roche hs-cTnT, 0.94; Siemens cTnI-Ultra, 0.95; and Abbott-Architect cTnI, 0.95 versus AUC for the standard assay, 0.90; p < 0.05 for comparisons). The optimal cut-offs for the sensitive cTn assays determined by the ROC curve in elderly patients differed from younger patients, and all the assays had higher sensitivity and lower specificity in older patients compared with the younger patients.
The authors concluded that sensitive assays for cTn have high diagnostic accuracy in the elderly.
This study provides additional support for use of sensitive troponin assays for triage of patients with chest pain (Keller et al., N Engl J Med 2009;361:868-77, and Reichlin et al., N Engl J Med 2009;361:858-67). This study not only confirms the utility of these assays in elderly patients, but also highlights the need to consider the appropriate pretest probability of acute coronary syndrome in interpreting the results of these tests.
Keywords: Myocardial Infarction, Acute Coronary Syndrome, Biological Markers, Early Diagnosis, Troponin
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