This study aimed to assess the association between serum sST2 level and plaque vulnerability in ACS patients. It is hypothesized that serum sST2 level may be related to plaque components and closely associated with plaque vulnerability.

Serum soluble suppression of tumorigenicity-2 (sST2) has emerged as a novel biomarker of atherosclerotic disease. This study aimed to investigate whether elevated serum sST2 level is related to coronary plaque components detected on coronary computed tomography angiography (CCTA) and plaque vulnerability in non-ST elevation acute coronary syndromes (ACS) patients. 167 lesions in 120 non-ST elevation ACS patients were prospectively enrolled and evaluated by CCTA in this study. Blood were taken from antecubital vein during patient's hospitalization for angiography. Serum sST2 level was measured by commerical ELISA kits (Presage ST2 Assay Kit, Critical Diagnostics). CCTA were performed using a 320-slice CT scanner (Aquilion ONE, Toshiba Medical Systems, Otawara, Japan). Coronary plaque components were analyzed cross each of the lesions using commercialized software package (QAngio CT, Medis, The Netherlands).

Inclusion Criteria:

1. Clinical diagnosis of non-ST-elevation ACS

   1. Non-ST-elevation myocardial infarction
   2. Unstable angina

2. Age from 18 to 75 years

3. Underwent CCTA

Exclusion Criteria:

1. Patients needed an immediate (< 2 h) or early invasive strategy (< 24 h) according to guidelines:

   1. Haemodynamic instability
   2. Cardiogenic shock
   3. Life-threatening arrhythmias or cardiac arrest
   4. Mechanical complication
   5. Acute heart failure
   6. Dynamic ST or T wave changes
   7. GRACE score > 140

2. Patients with previous history of:

   1. Coronary artery bypass graft surgery or percutaneous coronary intervention (PCI)
   2. Immune system disorder
   3. Tumor
   4. Acute/chronic infection
   5. Statin use within 3 months
   6. Atrial fibrillation
   7. End-stage renal failure
   8. Iodine-containing contrast allergy

3. Patients with no significant (≥ 50%) stenosis on major epicardial vessels after CCTA performance

4. Patients refused subsequent angiography after CCTA performance

5. Patients with total obstruction on major epicardial vessel

6. Patients with insufficient image quality for QAngioCT analysis

Between January 2019 and December 2019, a total of 120 patients with 167 lesions were included in our study for final analysis.