Abstract 507: Effects of Arteriole Tortuosity on Platelet Activation and Collision in Thrombosis
Introduction: Thrombosis and artery tortuosity are major contributors to cardiovascular disease. A fundamental gap exists in understanding how tortuosity regulates thrombosis through modification of blood flow. Accordingly, the objective of this research was to elucidate the physical mechanisms of artery tortuosity in thrombus formation.
Hypothesis: An increase in arteriole tortuosity promotes platelet adhesion to the convex surface of the endothelium by increasing platelet collisions and shear-induced platelet activation.
Methods: Platelet-mediated thrombosis was computationally simulated in 100-μm diameter vessels with sinusoidal shapes. The model used a discrete element algorithm for transport, collision, shear-induced activation, and receptor-ligand adhesion and aggregation of individual platelets. For a given simulation, platelets were set to be either (1) unactivated, (2) pre-activated, or (3) activated by shear stress. Tortuosity values (ratio of amplitude to wavelength) were set from 0 to 0.23, average velocity was 0.1 cm s-1, and Reynolds number was 0.1.
Results: For cases with platelets subject to shear-induced activation, increased tortuosity increased platelet activation, and platelets adhered to the convex endothelial wall, where shear stress was highest, while negligible numbers of platelets contacted the concave wall. For cases in which all platelets were previously activated, however, considerable platelet adhesion occurred on the concave wall. For cases with unactivated platelets in tortuous arterioles, as tortuosity increased, platelet contacts with the concave wall decreased until reaching the same value as the convex wall. Additionally, for cases with unactivated platelets, collisions between platelets was highest for the straight vessel, and collisions with walls throughout the entire arteriole were relatively negligible for straight and highly tortuous arterioles, but much larger for arterioles with intermediate tortuosity.
Conclusions: Shear-induced activation due to tortuosity generates platelet adhesion to the convex wall of arterioles. Increased tortuosity increases platelet activation, though the relationship between tortuosity and platelet collisions is less evident.
- © 2012 by American Heart Association, Inc.