Multidirectional wall shear stress is associated with thrombotic risk in isolated coronary artery ectasia.

Background: Thrombosis is a critical and lethal complication of isolated coronary artery ectasia (iCAE), potentially linked to hemodynamic changes, particularly wall shear stress (WSS) alterations. However, the association between thrombosis and multidirectionality of blood flow, and thus of WSS, is not well defined. Methods: This study retrospectively enrolled 34 patients diagnosed with iCAE. In total, 53 ectatic coronary arteries were identified for hemodynamics analysis, of which 11 had thrombosis and 42 did not. We used an automated workstation for coronary three-dimensional reconstruction and conducted computational fluid dynamics (CFD) analysis. Particularly, we analyzed the mean changes in the following multidirectional WSS metrics at the ectatic segments: time-averaged WSS (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), transverse WSS (transWSS), cross-flow index (CFI), and topological shear variation index (TSVI). Results: Local TAWSSmean, OSImean, RRTmean, transWSSmean, CFImean, and TSVImean of iCAE with thrombosis were significantly higher than those of iCAE without thrombosis (p < 0.05 for all). Logistic regression analyses indicated that RRTmean (OR = 1.010, 95% CI: 1.002-1.019, p = 0.021) and transWSSmean (OR = 1.992, 95% CI: 1.257-2.939, p = 0.003) were independently associated with the risk of thrombosis among patients with iCAE. The RRTmean + transWSSmean model [Area Under the Curve (AUC) = 0.911] exhibited a greater capacity for identifying the risk of thrombosis among patients with iCAE compared to maximum vascular diameter (MVD) (AUC = 0.789, p = 0.048). Conclusions: Multidirectional WSS metrics can help identify iCAE with a higher risk of thrombosis. It can improve thrombosis risk stratification.