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

tool to evaluate the drug distribution into different regions of the arterial domain, thus
providing fundamental indications on the effectiveness of each procedure in the
treatment of the SB lesions. The aim of the present work is to analyze drug distribution
in the arterial wall after different stenting procedures (namely provisional side branch
(PSB) and culotte technique (C)) by means of computational method developed in
[3,4,7].
3. MATERIALS AND METHODS
In order to provide realistic configurations of the device implanted in the coronary
bifurcation an explicit dynamic finite element model was developed. A model of
coronary bifurcation is created with an angle of 45°, a thickness of the arterial wall of
0.9 mm and internal diameters of the main branch (MB) and SB equal to 2.78 and 2.44
mm, respectively. The stent geometry resembles a commercial device Multilink Vision
(Abbott Laboratories, Abbott Park, IL; USA). Two different stenting procedures were
investigated (Fig. 1): (i) the PSB approach which is a single-stent procedure consisting
in the implantation of a stent in the MB across the bifurcation followed by a final
kissing balloon (FKB) inflation to free the SB access from stent struts; (ii) the culotte
(C) procedure, a two-stent technique in which, after a PSB stenting, another stent is
inserted in the SB with a wide stent overlap in the proximal part of the MB. This
procedure is ended with the FKB inflation.
Figure 1: Coronary bifurcations after stents implantation using the provisional side branch
(PSB) and the culotte (C) techniques.
The stented configurations are achieved running structural analysis by means of
ABAQUS/Explicit with the method developed in Gastaldi et al. [8]. These final
configurations are then used to perform the analysis of fluid dynamics and drug release
using an in-house code [3,9]. Specifically, a finite element method is used to couple the
blood flow and the intramural plasma filtration in rigid arteries. Under the assumption
of Newtonian rheology, the former is achieved by using the incompressible Navier-
Stokes equations while the latter is described by means of Darcy's law.
In order to reproduce the physiological coronary flow rate within a cardiac beat, a
steady parabolic velocity profile is applied at the inlet of the artery bifurcation reaching
a peak of 240 mm/s while 70/30 flow division is applied at the outflow of the MB and
SB, respectively.
The velocity fields in the arterial wall and in the lumen are then used to perform the
drug release according to the model developed in [4]. This model relies on a multiscale
strategy involving a lumped parameter model (0D) that accounts for drug release in the
stent coating, a 1D model to describe the complex stent geometry and a 3D model for
the drug transfer in the lumen and in the arterial wall. The model reproduces the drug