Diagnostic sensitivity of high-sensitivity troponin T for acute myocardial infarction in patients with chest pain

Abstract

IntroductionThe diagnosis of acute myocardial infarction (AMI) is based on an increase in plasma troponin levels above the 99th percentile of a healthy reference population values. On admission, over 30% of patients with AMI do not have specific symptoms and up to 70% of them may have normal or non-diagnostic ECG recordings. In these patient subgroups cardiac troponin assays may play a critical role in diagnosing AMI. Several diagnostic kits with enhanced analytic sensitivity (high-sensitivity kits) have been developed recently. Aim of studyTo compare diagnostic sensitivity of troponin I (cTnI) and high-sensitivity troponin T (hs-cTnT) in the diagnosis of acute myocardial infarction in patients with chest pain. Type of studyProspective, observational. Patients and methodsWe evaluated prospectively 107 consecutive patients [median (inter-quartile range) age: 64 (55–75) years; 29 women] admitted to intensive cardiac care unit for chest pain, with admission cTnI levels <0.1μg/l. In all patients, the parameters determined on admission included their levels of cTnI (chemiluminiscence immunoassay with microparticles, Abbott, Architect i2000 analyzer), hs-cTnT (electrochemiluminiscence immunoassay; Roche Cobas e411 analyzer), and myoglobin (immunoturbidimetry). The diagnosis of AMI was established by the attending cardiologist (using the “universal” definition of acute myocardial infarction). The cTnI and hs-cTnT cut-off values for AMI were 0.033μg/l and 14ng/l, respectively. Troponin I levels were again determined at 6 and 12h after admission. ResultsA total of 50 patients (46.7%) were diagnosed to have AMI with ST-segment elevation (STEMI), 35 patients (32.7%) developed AMI without STE (non-STEMI), 10 patients (9.3%) experienced a Type 2 AMI, four patients (3.7%) had unstable angina, and eight patients (7.5%) chest pain of non-coronary etiology (most often vertebrogenic pain). The diagnostic sensitivity of admission cTnI and hs-cTnT levels for AMI was 72% and 78%, respectively (p=0.1814). The correlation between cTnI and hs-cTnT was 0.67 (p<0.001; Spearman rank correlation coefficient). The diagnostic sensitivity of admission hs-cTnT and cTnI in STEMI patients was 82% vs. 70%, respectively (p=0.0771). In non-STEMI patients, similar baseline cTnI and hs-cTnT diagnostic sensitivity was found, 74.3% and 71.4%, respectively (p=0.91). ConclusionPatients with STEMI showed a trend toward a baseline diagnostic sensitivity of hs-cTnT superior to that of cTnI. In non-STEMI patients, the sensitivity of admission cTnI and hs-cTnT was similar.