Soluble Lectin-Like Oxidized LDL Receptor-1 and High-Sensitivity Troponin T as Diagnostic Biomarkers for Acute Coronary Syndrome

– Improved Values With Combination Usage in Emergency Rooms –

Abstract

Background: Although highly sensitive assays for troponin T (hs-TnT) have been developed, the sensitivity and specificity of hs-TnT for diagnosing acute coronary syndrome (ACS) remains imperfect. We evaluated the diagnostic value of a new biomarker of plaque vulnerability (soluble lectin-like oxidized low-density lipoprotein receptor-1, sLOX-1) as compared with hs-TnT in the emergency room (ER). Methods and Results: Plasma sLOX-1 and serum hs-TnT levels were measured in 200 consecutive patients presenting with chest symptoms and ECG abnormalities in the ER (116 ST elevation ACS [STEACS], 44 non-ST elevation ACS [NSTEACS], 40 non-ACS). The non-ACS group consisted of patients with cardiovascular diseases such as coronary spastic angina pectoris, pulmonary thromboembolism, perimyocarditis and takotsubo cardiomyopathy. Levels of sLOX-1 and hs-TnT were significantly higher in STEACS and NSTEACS than in non-ACS patients. The receiver-operating characteristic (ROC) curves of sLOX-1 and hs-TnT for detecting ACS, using the non-ACS patients as negative references, showed that the area under the curve (AUC) values of sLOX-1 and hs-TnT were 0.769 and 0.739, respectively. In the lower hs-TnT (<0.0205ng/ml) subgroup, the AUC value of the ROC curve of sLOX-1 for detecting ACS was 0.869. Conclusions: The diagnostic value for ACS was comparable between sLOX-1 and hs-TnT, and the accuracy of ACS diagnosis appeared to improve when sLOX-1 and hs-TnT were measured in combination. (Circ J 2011; 75: 2862-2871)