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Circumferential vascular deformation after stent implantation alters wall shear stress evaluated with time-dependent 3D computational fluid dynamics models. J Appl Physiol (1985) 2005 Mar;98(3):947-57

Date

11/09/2004

Pubmed ID

15531564

DOI

10.1152/japplphysiol.00872.2004

Abstract

The success of vascular stents in the restoration of blood flow is limited by restenosis. Recent data generated from computational fluid dynamics (CFD) models suggest that stent geometry may cause local alterations in wall shear stress (WSS) that have been associated with neointimal hyperplasia and subsequent restenosis. However, previous CFD studies have ignored histological evidence of vascular straightening between circumferential stent struts. We tested the hypothesis that consideration of stent-induced vascular deformation may more accurately predict alterations in indexes of WSS that may subsequently account for histological findings after stenting. We further tested the hypothesis that the severity of these alterations in WSS varies with the degree of vascular deformation after implantation. Steady-state and time-dependent simulations of three-dimensional CFD arteries based on canine coronary artery measurements of diameter and blood flow were conducted, and WSS and WSS gradients were calculated. Circumferential straightening introduced areas of high WSS between stent struts that were absent in stented vessels of circular cross section. The area of vessel exposed to low WSS was dependent on the degree of circumferential vascular deformation and axial location within the stent. Stents with four vs. eight struts increased the intrastrut area of low WSS in vessels, regardless of cross-sectional geometry. Elevated WSS gradients were also observed between struts in vessels with polygonal cross sections. The results obtained using three-dimensional CFD models suggest that changes in vascular geometry after stent implantation are important determinants of WSS distributions that may be associated with subsequent neointimal hyperplasia.

Author List

LaDisa JF Jr, Olson LE, Guler I, Hettrick DA, Kersten JR, Warltier DC, Pagel PS

Authors

John LaDisa PhD Assistant Professor in the Biomedical Engineering department at Marquette University
Paul S. Pagel MD, PhD Professor in the Anesthesiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Arteries
Blood Flow Velocity
Blood Pressure
Blood Vessel Prosthesis
Computer Simulation
Elasticity
Equipment Failure Analysis
Graft Occlusion, Vascular
Humans
Hyperplasia
Models, Cardiovascular
Prosthesis Failure
Severity of Illness Index
Shear Strength
Stents
Stress, Mechanical
Time Factors
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