It is well known that cardiac troponin T (TnT) elevation on admission indicates a high-risk subgroup among patients with non–ST-segment elevation acute coronary syndrome (NSEACS). Although the mechanism of TnT elevation is speculated to be the microthromboembolism from unstable plaques, it has not been clarified. The aim of this study is to clarify the association between the serum TnT elevation and the angioscopically evaluated morphology of culprit lesion in the patients with NSEACS.

Among 113 patients with NSEACS who had significant coronary stenosis, 62 patients with successful angioscopic examination were prospectively and consecutively enrolled from October 2001 to August 2002. Patients were divided into 2 groups according to the serum TnT level measured before percutaneous coronary intervention: TnT-positive or TnT-negative group. Thrombus and plaque color at culprit lesion were evaluated by angioscopy and were compared between the groups. Plaque color was determined as yellow or white, and thrombus as none, small, or large. Three different definitions for TnT-positive (≥0.1, ≥0.03, and ≥0.01 ng/mL) were used and the sensitivity and specificity for detecting thrombus was compared.

Prevalence of thrombus, large thrombus, and yellow plaque were all higher in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Angiographic slow-flow occurred more frequently after percutaneous coronary intervention in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Sensitivity/specificity of detecting large thrombus were 33%/100%, 44%/91%, and 56%/83% when TnT-positive was defined as TnT ≥ 0.1, ≥0.03, and ≥0.01 ng/mL, respectively.

Serum TnT level was significantly associated with the prevalence of thrombus and yellow plaque at the culprit lesions of NSEACS. Troponin T, when positive was defined as ≥0.01 ng/mL, still have a high specificity for detecting intracoronary thrombus.