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Annals of Biomedical Engineering

, Volume 38, Issue 5, pp 1893–1907 | Cite as

The Influence of Strut-Connectors in Stented Vessels: A Comparison of Pulsatile Flow Through Five Coronary Stents

  • Sanjay Pant
  • Neil W. Bressloff
  • Alexander I. J. Forrester
  • Nick Curzen
Article

Abstract

The design of coronary stents has evolved significantly over the past two decades. However, they still face the problem of in-stent restenosis, formation of neointima within 12 months of the implant. The biological response after stent implantation depends on various factors including the stent geometry which alters the hemodynamics. This study takes five different coronary stent designs, used in clinical practice, and explores the hemodynamic differences arising due to the difference in their design. Of particular interest is the design of the segments (connectors) that connect two struts. Pulsatile blood flow analysis is performed for each stent, using 3-D computational fluid dynamics (CFD), and various flow features viz. recirculation zones, velocity profiles, wall shear stress (WSS) patterns, and oscillatory shear indices are extracted for comparison. Vessel wall regions with abnormal flow features, particularly low, reverse, and oscillating WSS, are usually more susceptible to restenosis. Unlike previous studies, which have tried to study the effect of design parameters such as strut thickness and strut spacing on hemodynamics, this work investigates the differences in the flow arising purely due to differences in stent-shape, other parameters being similar. Two factors, the length of the connectors in the cross-flow direction and their alignment with the main flow, are found to affect the hemodynamic performance. This study also formulates a design index (varying from 18.81% to 24.91% for stents used in this study) that quantifies the flow features that could affect restenosis rates and which, in future, could be used for optimization studies.

Keywords

Stents Restenosis Computational fluid dynamics Coronary artery Pulsatile blood flow 

Abbreviations

CFD

Computational fluid dynamics

WSS

Wall shear stress

CAD

Coronary artery disease

BMS

Bare metal stents

DES

Drug eluting stents

ST

Stent thrombosis

LDV

Laser doppler velocimeter

LAD

Left anterior descending

EC

Endothelial cell

FEA

Finite element analysis

NURBS

Non-uniform rational B-splines

MOSI

Modified oscillatory shear index

HLRFI

Hemodynamic low and reverse flow index

Notes

Conflict of Interest

Pant, Bressloff, and Forrester have no financial relationships with any organizations that could influence this work. Curzen is involved in unrestricted research grants with Medtronic and Medicell. He also advises Medtronic, Boston Scientific, Cordis, Abbott, and Lilly.

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Copyright information

© Biomedical Engineering Society 2010

Authors and Affiliations

  • Sanjay Pant
    • 1
  • Neil W. Bressloff
    • 1
  • Alexander I. J. Forrester
    • 1
  • Nick Curzen
    • 2
    • 3
  1. 1.School of Engineering SciencesUniversity of SouthamptonSouthamptonUK
  2. 2.Southampton University Hospitals NHS TrustSouthamptonUK
  3. 3.School of MedicineUniversity of SouthamptonSouthamptonUK

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