Welcome to the 8th

European Bifurcation Club

12-13 October 2012 - Barcelona

Simulation of drug release

(what for)?

Gabriele Dubini

Professor of Biomechanics

at Politecnico di Milano

Aim of the study

Assessment of the effectiveness of different DES

stenting techniques in supplying drug to the arterial wall.

Computational analysis combining virtual stent implantation (a),

fluid dynamics (c) and drug release (b).

Computational model are able to provide fundamental indices which are

hardly detectable by means of in vitro or in vivo experiments.

Aim of the study

Mechanics: analysis of balloon/stent expansion

Fluid dynamics Mass transfer

blood flow

intramural plasma

filtration

drug release to the artery

drug release from the polymer

(Heparin)

• Realistic geometries of the deformed configurations

• Realistic drug distribution

within the arterial wall

• Effect of the stent struts

overlapping and/or

incomplete stent apposition

• Hemodynamic field

Zunino et al., CMAME (2009)

Stenting procedures

Tryton-based Culotte

Stenting procedures

Provisional

Side Branch Culotte

Tryton-based

Culotte

Fluid dynamics model

70/30 flow division MB/SB

x plasma

filtration

plasma

filtration

Deeper drug penetration

into the arterial wall in the

case where the plasma

filtration is accounted for

Drug release: multiscale strategy

Multiscale strategy:

0D model for the release rate in the stent coating;

3D model for the drug release within the arterial wall;

1D model to handle complex geometry of the DESs.

0D

1D

3D

Cutrì et al. Drug delivery patterns for different

stenting techniques in coronary bifurcations: a

comparative computational study.

Biomechanics Model Mechanobiol. 2012.

Quantities of interest

dw(x) = T-1 c

w(t,x)dt

0

T

ò

dw,m

(V ) = V -1 dw(x)dV

V

ò

Dose

Mean value of the dose

4 control volumes:

• red: whole arterial domain (V-TOT)

• blue box: proximal region of the main branch (V-MBP)

• green box: distal region of the main branch (V-MBP)

• yellow box: side branch (V-MBP)

Results R

ele

as

e o

n

Re

lea

se o

ff

PSB Culotte Tryton-based Culotte

Results

Results

Drug loss due to overlapping

Results

Results

Drug supply

to the SB

Results

BMS Tryton disturbs drug elution

Conclusions

Implementation of a drug-eluting stent model

based on realistic structural simulations.

Importance of a DES deployment in the side

branch to adequately supply drug.

Reduction of drug uptake due to stent

overlapping and incomplete stent apposition.

Acknowledgments

University of Pittsburgh

Prof. Paolo Zunino

Politecnico di Milano

Dr. Elena Cutrì

Prof. Francesco Migliavacca

Ing. Stefano Morlacchi

Ing. Claudio Chiastra