How cross-sectional eccentricity modulates thrombus deposition: A hemodynamic study of coronary artery aneurysms

Coronary artery aneurysms (CAA) pose significant clinical risks of thrombosis and ischemia, yet the geometric determinants beyond aneurysm size remain poorly defined, making their understanding essential for improving early diagnosis and tailored interventions. We analyzed serial coronary computed tomography angiography data from 80 CAA patients with two serial scans, classifying them into the non-thrombus group and the thrombus group based on the final scan. All CAA morphological characteristics were quantified and compared between groups. Computational fluid dynamics simulations were performed to extract hemodynamic parameters, including wall shear stress (WSS) and vortex flow (Q-criterion), for a comparative inter-group analysis. An integrated analysis of morphological and hemodynamic data was conducted to identify determinants of thrombosis. Among all geometric variables, cross-sectional eccentricity (CE) was the only parameter showing significant baseline differences (P < 0.001). Lower CE values (higher eccentricity) were associated with adverse shear conditions and pronounced near-wall vortex coverage, characterized by prominent “neckerchief”-shaped vortices on the CAA. Regression analyses showed CE alone explained 33%–40% of the variance in these disturbed flow regions. Near-wall vortex correlated with low-WSS regions. Spatial and temporal relationships indicated that CE and vortex consistently predicted sites of subsequent thrombus deposition. This study identifies CE as a critical noninvasive predictor of thrombus. CE promotes thrombus formation in CAA by creating a pro-thrombotic environment characterized by “neckerchief”-shaped vortices at the aneurysm neck. These findings clarify the geometry–hemodynamics–thrombosis relationship and provide key evidence for early clinical assessment of thrombotic risk in CAA.