Researchers leading an international study identify a two-year window in which specific characteristics of coronary artery plaques can most accurately predict the risk of acute coronary syndrome (ACS). The Exploring the Mechanism of Plaque Rupture in Acute Coronary Syndrome Using Coronary CT Angiography and Computational Fluid Dynamics II (EMERALD II) study found that plaques with more severe narrowing, greater volume and impaired blood flow were far more likely to lead to heart attacks sooner. Two-year time frame "Higher luminal stenosis, plaque burden and local hemodynamics were associated with shorter test-to-event time," said the team, led by Seokhun Yang, MD, from Seoul National University of College of Medicine in South Korea. “The predictability for ACS culprit lesions based on the combined degree of stenosis, number of APC, plaque burden, significantly decreased beyond 2 years, suggesting a prognostic time frame of 2 years.” One notable finding was that lesions with all 4 characteristics presented the highest ACS risk, indicating a nearly 50% chance (proportion of lesions becoming ACS culprit: 49.3%; P < 0.001) that such plaques would cause a heart attack within two years. Preventing ACS “Lesions with all 4 characteristics…highlights the importance of comprehensive assessment of lumen, plaque, and hemodynamics for precise targeted PCI in preventing near-term ACS," the team said. The team emphasized that these insights could refine clinical decision-making, especially regarding when to choose aggressive treatments like stenting versus continuing medical therapy. Future studies are planned to validate these results in broader populations and explore the use of more advanced imaging tools. Methodology The EMERALD II study enrolled 351 patients who had coronary CT angiography (CTA) and later developed acute coronary syndrome (ACS) within 1 month to 3 years. Researchers matched coronary lesions identified on CTA to culprit or nonculprit lesions confirmed by invasive coronary angiography at the time of ACS. The study also assessed four lesion characteristics: degree of stenosis, plaque burden, number of adverse plaque characteristics (APCs) and change in CTA-derived fractional flow reserve (ΔFFRCT). Patients were categorized by test-to-event time (<1 year, 1–2 years, 2–3 years) to examine how lesion features predicted ACS risk over time. Source: Yang S, Jung JW, Park SH, et al. Prognostic Time Frame of Plaque and Hemodynamic Characteristics and Integrative Risk Prediction for Acute Coronary Syndrome. JACC Cardiovasc Imaging 2025. (Article in Press). Image Credit: LIGHTFIELD STUDIOS – stock.adobe.com