Nitric Oxide Distribution Correlates with Intraluminal Thrombus in Abdominal Aortic Aneurysm: A Computational Study.

Intraluminal thrombus (ILT) in the abdominal aortic aneurysm (AAA) is associated with disease progression and complications. This study investigates the relationship between nitric oxide (NO) concentration and ILT in AAA patients using patient-specific computational fluid dynamics (CFD) models. Four AAA patients with ILT were enrolled. Patient-specific models of the aorta and branch arteries were constructed followed by CFD simulations. NO concentration was modeled based on endothelial shear stress response and its transport within the arterial lumen and wall. Hemodynamic parameters, including wall shear stress (WSS) and its derivatives, were analyzed alongside NO distribution. ILT accumulation was primarily located in the infrarenal abdominal aorta. Regions of decreased NO concentration correlated with ILT accumulated areas, whereas regions with decreased TAWSS and increased OSI were less consistent with ILT accumulation. A negative correlation was observed between the thrombus area and NO concentration, with p values of less than 0.001 for four patients. The time-average area NO concentration values of lumen area with ILT were lower than those of non-ILT sections. Spatially, NO was unevenly distributed, with thicker thrombus in regions of lower NO concentration. NO distribution could serve as a better potential personalized marker for thrombosis prediction in AAA compared to WSS-derived parameters.