Background: Cardiac troponin-T (CTNT) has high specificity for heart and high sensitivity for cardiac damage. Recently, high sensitive troponin-T (HTNT) was developed with enhanced detecting power for cardiac damage at low serum level of CTNT. However, the comparison between HTNT and conventional cardiac enzymes for detecting cardiac damage and clinical outcomes is little known. Methods: Conventional cardiac enzymes including creatinine kinase (CK), CK-MB, troponin-I (Tn-I), CTNT with HTNT were checked in 97 patients who visited Chonnam National University Hospital Emergency Room complaining of chest pain. HTNT was analyzed with Roche Elecsys® TnT-hs. Follow-up cardiac enzymes were checked at 3 and 6 hours. Cuff-off value of CTNT was 0.1 ng/ml and that of HTNT was 0.014 ng/ml. In-hospital complication was the composite of cardiogenic shock, new-onset heart failure, fatal arrhythmia, and major bleeding. Acute myocardial infarction was confirmed by coronary angiography. Results: 70 (72.2%) patients had final diagnosis of acute coronary syndrome (ACS). HTNT showed better diagnostic accuracy than CTNT and Tn-I in the diagnosis of STEMI (100% vs. 66.7% vs. 83.3%, p=0.003) and total AMI (100% vs. 88.2% vs. 94.1%, p=0.029). The area under the curve (AUC) for the diagnosis of STEMI was 0.887 (95% confidence interval [CI] 0.78-0.99) with HTNT vs. 0.774 (95% CI 0.53-1.02) with CTNT. AUC for the diagnosis of total AMI was 0.930 (95% CI 0.88-0.98) with HTNT vs. 0.882 (95% CI 0.78-0.98) with CTNT. 34 (35.1%) patients had significant stenosis in coronary angiogram. HTNT showed better diagnostic accuracy for significant stenosis than CTNT and Tn-I (60.6% vs. 41.2% vs. 47.1%, p=0.001; AUC 0.705 [95% CI 0.60-0.82] vs. 0.618 [95% CI 0.50-0.74] vs. 0.675 [95% CI 0.55-0.80]). HTNT showed better predictability for in-hospital complication than CTNT and Tn-I (65.2% vs. 52.2% vs. 47.8%, p=0.016). HTNT showed better correlation with troponin-I than CTNT (Pearson r; baseline = 0.626 vs. 0.616; 3 hours = 0.998 vs. 0.998; 6 hours = 0.714 vs. 0.635) as well as CK, CK-MB. Conclusions: Initial serum level of HTNT had higher diagnostic accuracy for the diagnosis of AMI and significant stenosis than that of CTNT and Tn-I. Also it had better predictability for in-hospital complication than CTNT and Tn-I.
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