Different plaque morphology may have an important effect on the prognosis of acute myocardial infarction (AMI), as recent studies show that patients with plaque rupture have a significantly higher risk of cardiac events compared with those with plaque erosion. The primary purpose of this study is to find risk factors and biomarkers for different culprit lesion morphology to perform accurate risk stratification and determine an appropriate treatment strategy for patients with AMI.

Acute myocardial infarction (AMI), which results from coronary artery occlusion due to thrombosis, remains the leading cause of death and disability worldwide. Pathological studies have demonstrated that plaque rupture accompanied by subsequent thrombus formation is the main mechanism responsible for AMI, accounting for approximately two thirds of cases; the remaining approximately one third of cases are the result of plaque erosion. Moreover, previous studies showed that the risk of cardiovascular events is significantly higher in patients with plaque rupture compared to those with plaque erosion. The EROSION study suggested that in patients with acute coronary syndrome presenting with plaque erosion, conservative treatment with anti-thrombotic therapy may be a reasonable option instead of stents implantation. Therefore, it is important to differentiate between the culprit morphologies in order to perform an accurate risk stratification and determine a personalized treatment strategy with the goal to improve the prognosis of patients with AMI.

Optical coherence tomography (OCT), a newly developed high resolution near infrared light-based intravascular imaging modality, can visualize the microstructure of atherosclerotic plaques such as the fibrotic cap, lipid pool, thrombi, and so on, and has been considered as the golden standard for differentiating plaque morphology in vivo.

In this study, we aimed to find risk factors and biomarkers for culprit lesion morphology as assessed by OCT.

Inclusion Criteria:

• Patients with ST-segment elevation myocardial infarction (defined as continuous chest pain lasted >30 min, ST-segment elevation >0.1 mV in at least two contiguous leads or new left bundle-branch block on the 18-lead electrocardiogram (ECG), and an elevated troponin I level)
• Age ≥18 years
• Provide written informed consent

Exclusion Criteria:

• Cardiac shock
• History of coronary artery bypass graft
• Left main diseases, extremely tortuous or heavily calcified vessels, or chronic total occlusion
• Inability to obtain Thrombolysis in myocardial infarction flow grade ≥ 2

Patients (age ≥18 years) who presented with STEMI and underwent emergent procedures were prospectively screened for OCT examination of the culprit lesion.