Characteristics of non-culprit coronary artery lesions assessed by intravascular ultrasound in patients with ST-segment elevation myocardical infarction.

Background: Non-culprit coronary lesions are increasingly recognized as an important source of recurrent cardiovascular events in patients with ST-segment elevation myocardial infarction (STEMI). Intravascular ultrasound (IVUS) provides detailed assessment of plaque morphology; however, data in real-world STEMI populations, particularly in Vietnam, remain limited. Objective: To characterize morphological features and associated factors of non-culprit coronary lesions using IVUS in STEMI patients. Methods: This prospective observational study included 103 STEMI patients with multivessel disease undergoing primary percutaneous coronary intervention. A total of 118 non-culprit lesions were assessed by IVUS. High-risk plaque features were defined as the presence of at least two of the following: minimal lumen area (MLA) <4.0 mm², plaque burden ≥70%, spotty calcification, or lipid core. Clinical, lipid, and lesion-related factors associated with high-risk features were analyzed. Results: High-risk plaque characteristics were common, with 66% of lesions exhibiting ≥2 high-risk features. Calcified plaques predominated (75.4%), with spotty calcification observed in 52.5% of lesions, while lipid core was less frequent (14.4%). MLA <4 mm² and plaque burden ≥70% were present in 68% and 53% of lesions, respectively. Diabetes mellitus (44.4% vs. 19.4%, p=0.015), dyslipidemia (79.4% vs. 54.2%, p=0.017), and higher non-HDL cholesterol levels (p=0.005) were significantly associated with ≥2 high-risk features. Lesions located in the left anterior descending artery were more likely to exhibit high-risk characteristics (48.1% vs. 25.6%, p=0.019). In multivariable analysis, diabetes (OR 4.40, p=0.011), non-HDL cholesterol (OR 3.40, p=0.002), and LAD location (OR 3.35, p=0.027) were independent predictors. Conclusions: Non-culprit lesions in STEMI patients frequently demonstrate multiple high-risk features on IVUS. Diabetes, non-HDL cholesterol, and LAD location are independently associated with high-risk plaque phenotypes. These findings support the role of IVUS in comprehensive risk stratification of non-culprit lesions in multivessel STEMI.