Measurement of troponin I 48h after admission as a tool to rule out impaired left ventricular function in patients with a first myocardial infarction

Abstract

AbstractFew studies have evaluated cardiac troponin I (cTnI) as a marker for infarct size and left ventricular (LV) dysfunction. Here we investigated the ability of a single-point cTnI, measured with a second-generation assay (Access AccuTnI), to estimate infarct size and assess LV function in patients with a first myocardial infarction (AMI). cTnI measurements were performed 12 and 48h after admission in 63 consecutive AMI patients. LV function was evaluated by gated single-photon emission computed tomography (SPECT) and infarct size was estimated by CK-MB peak and SPECT myocardial perfusion. LV function and infarct size were evaluated by SPECT before hospital discharge. SPECT was also repeated 3months later. Significant correlations (p<0.001) were found between cTnI at 12 and 48h and both the peak CK-MB (r=0.61 and r=0.82, respectively) and the perfusion defect size at SPECT (r=0.55 and r=0.61, respectively). cTnI at 12 and 48h were inversely related (p<0.001) to LV ejection fraction (LVEF) assessed both early (r=–0.45 and r=–0.57, respectively) and 3months after AMI (r=–0.51 and r=–0.69, respectively). cTnI >14.8 μg/L at 48h predicted an LVEF <40% at 3months with a sensitivity of 100% [95% confidence interval (CI) 73.5–100%], specificity of 65% (CI 49–79%), and a negative predictive value of 100%. Our findings demonstrate that a single cTnI measurement 48h after admission is useful for ruling out impaired LV function in a routine clinical setting.