ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

A COMPARISON BETWEEN STANDARD AND DEDICATED STENTS
FOR CORONARY BIFURCATIONS: STRUCTURAL AND FLUID
DYNAMIC NUMERICAL SIMULATIONS
1. ABSTRACT
C. Chiastra 1,2 , S. Morlacchi 1,2 , G. Dubini 1 and F. Migliavacca 1
Stenting implantation in coronary bifurcations remains a challenging area in
interventional cardiology. Nowadays the concurrent use of two devices is limited and
the culotte technique is a commonly applied procedure. A new dedicated device has
been proposed on the market to overcome the main drawback of this procedure which is
the wide overlap region in the main branch. The aim of this work is to investigate the
culotte technique both from a structural and fluid dynamic point of view, comparing the
behavior of the dedicated stent with a standard one.
Structural simulations of the stenting procedure were carried out by means of a
commercial finite element code. Then, obtained realistic final geometrical
configurations were used as fluid domains to perform transient CFD analyses.
The biomechanical influence of the two-stents culotte technique was investigated in
terms of easiness of implantation, von Mises stresses in the device, velocity and wall
shear stress (WSS) patterns. Results showed that the dedicated stent facilitates the
access to the main branch in comparison with the standard stent (63.4% of area
available for an optimal re-crossing against 10.9%) and reduces the metal-to-artery ratio
and the deformation of stent struts. Moreover, the dedicated stent caused a smaller area
(28.7% against 35.5%) with WSS lower than 0.1 Pa, values considered critical for the
restenosis process.
This work indicates that new dedicated approaches could contribute to improve the
biomechanical influence of the current treatment for coronary bifurcations.
2. INTRODUCTION
Percutaneous coronary interventions (PCI) in bifurcation lesions are associated with
lower procedural success and worse long-term outcomes as compared to PCI in simple
lesions [1]. Because of the asymmetrical shape and great anatomic variability present in
bifurcations, current PCI techniques with conventional stents may be laborious and
limited by the degree of anatomic/morphologic complexity encounter [2]. Even
common complex techniques with double stenting are associated with stent
underexpansion or gap at the side branch (SB) ostium, excessive metal density at the
carina, incomplete stent apposition, and stent distortion or disruption. To overcome
some of the limitations associated with conventional stenting in bifurcations, dedicated
bifurcation devices were developed and introduced [1].
In this work, the dedicated stent Tryton (Tryton medical, Newton, MA, USA) is
1
Laboratory of Biological Structure Mechanics (LaBS), Structural Engineering Department, Politecnico
di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy
2
Bioengineering Department, Politecnico di Milano, Piazza L. da Vinci 32, 20133 Milan, Italy