Cardiovascular diseases are the number one cause of death in the world, making the understanding of hemodynamics and development of treatment options imperative. The most common modality for treatment of occlusive coronary artery diseases is the use of stents. Stent design profoundly influences the postprocedural hemodynamic and solid mechanical environment of the stented artery. However, despite their wide acceptance, the incidence of stent late restenosis is still high (Zwart et al., 2010, “Coronary Stent Thrombosis in the Current Era: Challenges and Opportunities for Treatment,” Current Treatment Options in Cardiovascular Medicine, 12(1), pp. 46–57), and it is most prevailing at the proximal and distal ends of the stent. In this work, we focus our investigation on the localized hemodynamic effects of compliance mismatch due to the presence of a stent in an artery. The compliance mismatch in a stented artery is maximized at the proximal and distal ends of the stent. Hence, it is our objective to understand and reveal the mechanism by which changes in compliance contribute to the generation of nonphysiological wall shear stress (WSS). Such adverse hemodynamic conditions could have an effect on the onset of restenosis. Three-dimensional, spatiotemporally resolved computational fluid dynamics simulations of pulsatile flow with fluid-structure interaction were carried out for a simplified coronary artery with physiologically relevant flow parameters. A model with uniform elastic modulus is used as the baseline control case. In order to study the effect of compliance variation on local hemodynamics, this baseline model is compared with models where the elastic modulus was increased by two-, five-, and tenfold in the middle of the vessel. The simulations provided detailed information regarding the recirculation zone dynamics formed during flow reversals. The results suggest that discontinuities in compliance cause critical changes in local hemodynamics, namely, altering the local pressure and velocity gradients. The change in pressure gradient at the discontinuity was as high as 90%. The corresponding changes in WSS and oscillatory shear index calculated were 9% and 15%, respectively. We demonstrate that these changes are attributed to the physical mechanism associating the pressure gradient discontinuities to the production of vorticity (vorticity flux) due to the presence of the stent. The pressure gradient discontinuities and augmented vorticity flux are affecting the wall shear stresses. As a result, this work reveals how compliance variations act to modify the near wall hemodynamics of stented arteries.
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February 2011
Research Papers
Hydrodynamic Effects of Compliance Mismatch in Stented Arteries
N. K. C. Selvarasu,
N. K. C. Selvarasu
Department of Mechanical Engineering,
Virginia Polytechnic Institute and State University
, 114-I Randolph Hall, Mail Code 0238, Blacksburg, VA 24061
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Danesh K. Tafti,
Danesh K. Tafti
Department of Mechanical Engineering,
e-mail: dtafti@vt.edu
Virginia Polytechnic Institute and State University
, 114-I Randolph Hall, Mail Code 0238, Blacksburg, VA 24061
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Pavlos P. Vlachos
Pavlos P. Vlachos
Department of Mechanical Engineering,
Virginia Polytechnic Institute and State University
, 114-I Randolph Hall, Mail Code 0238, Blacksburg, VA 24061
Search for other works by this author on:
N. K. C. Selvarasu
Department of Mechanical Engineering,
Virginia Polytechnic Institute and State University
, 114-I Randolph Hall, Mail Code 0238, Blacksburg, VA 24061
Danesh K. Tafti
Department of Mechanical Engineering,
Virginia Polytechnic Institute and State University
, 114-I Randolph Hall, Mail Code 0238, Blacksburg, VA 24061e-mail: dtafti@vt.edu
Pavlos P. Vlachos
Department of Mechanical Engineering,
Virginia Polytechnic Institute and State University
, 114-I Randolph Hall, Mail Code 0238, Blacksburg, VA 24061J Biomech Eng. Feb 2011, 133(2): 021008 (11 pages)
Published Online: January 31, 2011
Article history
Received:
May 31, 2010
Revised:
November 24, 2010
Posted:
December 22, 2010
Published:
January 31, 2011
Online:
January 31, 2011
Citation
Selvarasu, N. K. C., Tafti, D. K., and Vlachos, P. P. (January 31, 2011). "Hydrodynamic Effects of Compliance Mismatch in Stented Arteries." ASME. J Biomech Eng. February 2011; 133(2): 021008. https://doi.org/10.1115/1.4003319
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