title: Simulation of the microscopic process during initiation of stent thrombosis.
abstract: OBJECTIVE
  Coronary stenting is one of the most commonly used approaches to open coronary arteries blocked due to atherosclerosis. However, stent struts can induce stent thrombosis due to altered hemodynamics and endothelial dysfunction, and the microscopic process is poorly understood. The objective of this study was to determine the microscale processes during the initiation of stent thrombosis.
  
  
  METHODS
  We utilized a discrete element computational model to simulate the transport, collision, adhesion, and activation of thousands of individual platelets and red blood cells in thrombus formation around struts and dysfunctional endothelium.
  
  
  RESULTS
  As strut height increased, the area of endothelium activated by low shear stress increased, which increased the number of platelets in mural thrombi. These thrombi were generally outside regions of recirculation for shorter struts. For the tallest strut, wall shear stress was sufficiently low to activate the entire endothelium. With the entire endothelium activated by injury or denudation, the number of platelets in mural thrombi was largest for the shortest strut. The type of platelet activation (by high shear stress or contact with activated endothelium) did not greatly affect results.
  
  
  CONCLUSIONS
  During the initiation of stent thrombosis, platelets do not necessarily enter recirculation regions or deposit on endothelium near struts, as suggested by previous computational fluid dynamics simulations. Rather, platelets are more likely to deposit on activated endothelium outside recirculation regions and deposit directly on struts. Our study elucidated the effects of different mechanical factors on the roles of platelets and endothelium in stent thrombosis.
authors.affiliation: Cardiovascular Biomechanics Laboratory, Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA.
authors.forename: Jennifer K W
authors.initials: JK
authors.lastname: Chesnutt
authors.affiliation: Cardiovascular Biomechanics Laboratory, Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA; Biomedical Engineering Program, UTSA-UTHSCSA, San Antonio, TX, USA. Electronic address: hchan@utsa.edu.
authors.forename: Hai-Chao
authors.initials: HC
authors.lastname: Han
mesh_terms: D001792:Blood Platelets / Q000378:metabolism* / Q000473:pathology; D003328:Coronary Thrombosis / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003331:Coronary Vessels / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008955:Models, Cardiovascular; D015607:Stents
keywords: Computational simulation; Coronary arteries; Discrete element model; Endothelium activation; Shear-induced platelet activation; Stent thrombosis