ABSTRACT
Objective To investigate the diagnostic accuracy and the clinical usefulness of the combination of troponin I (cTnI) and copeptin detected in patients with suspected non-ST elevation myocardial infarction. Methods 176 patients presenting to the emergency departments with chest chocking or chest pain within 6 hours and without ST elevation on a 12-lead electrocardiogram (ECG) were enrolled in this study. The level of copeptin and cTnI was measured. The diagnosis was adjudicated by 2 independent experts.The diagnostic performance of them was assessed using ROC analysis , and the sensitivity and specificity of them were inferred based on the positive rate of two cardiac markers. Results (1)The levels of copeptin and cTnI in NSTEMI patients were markedly higher than other groups (P<0.05).(2)The AUCs of copeptin and cTnI were 0.846 and 0.683, and the 95%CI of two markers were 0.786 ~ 0.906 and 0.577 ~ 0.789, respectively. (3)Using 10.85 pmol/L as cut off value,the sensitivity and specificity of copeptin were 90% and 64%,and the positive predictive value and the negative predictive valueof NSTEMI diagnose were 42.4% and 95.6%,respectively.Using 0.05 ng/mL as cut off value,the sensitivity and specificity of cTnI were 42.5% and 94.1%,the positive predictive value and the negative predictive value were 68%and 84.8% for diagnosis of NSTEMI. (4)The copeptin level over 10.85 pmol/L in combination with cTnI could be used to detect NSTEMI with higher sensitivity than that of copeptin or cTnI alone (95% vs 90% vs 42.5%). The negative predictive value of the combination of copeptin and cTnI was increased , compared to that of copeptin or cTnI alone (97.7% vs 95.6% vs 85.7%). Conclusions Determination of copeptin in addition to cTnI can improves diagnostic performance , especially early after chest pain onset. It seems to allow a rapid and reliable rule out of NSTEMI.