D. COISNE M.D. Ph.D *, E. FOUCAULT PhD**, S HUBERSON PhD **

L. CHRISTAENS M.D. * ,J MERGY MD *, P. BRAUD PhD **

*Poitiers University Hospital. **CNRS-Poitiers University

Flow Dynamics in Left-Main Bifurcation

WSS and endothelium

From Chatzisisis JACC 2006

WSS is determined from velocity gradient and viscosityA negative correlation was found between intimal thickness and WSSLow WSS is strongly correlated to atherogenesisThe low WSS values distribution is in accordance with the frequent localization of atherosclerosis lesion

Atherosclerotic plaque distribution in LMCT Scan study

• LM bifurcation:

L Christiaens study :

• “Distribution of atherosclerotic plaques in the left main coronary artery bifurcation: influence of anatomic variations of the proximal left coronary artery segments. A multi-slice computed tomography study over 300 cases. ”

Atherosclerotic plaque distribution in LMCT Scan study

Atherosclerotic plaque distribution in LMCT Scan study

More than 70% of plaques are located close to low WSS zones

French TAXUS registry• Impact of bifurcation angle ??. T Shape vs Y Shape

EBC 2007Valencia

T LefebvreY Louvard

Flow dynamics in LM Bifurcation.

• Objective :

-Effect of the bifurcation angle on flow dynamic in case of provisional stenting of LM bifurcation

-Trajectography , Langragian approach

Flow dynamics in LM Bifurcation.

• Experimental setup :

Oscilloscope

Pulsatil pump

Centrifugal Pump

by-pass

BifurcationUnstead

y Flowmet

er

Laser sheet

CCD Camera

Flow dynamics in LM Bifurcation.

• Experimental setup :

Modelisation :

Synthetic flow : Arbitrary Wave Generator . + pulsatil pump

Bifurcation models in glass (90°,60°)

Ultra-fast PIV measurements (3 kHz – 1024x1024 – 50 periods )

Standard PIV (50 pts/period – 50 periods – 2Hz )

Scale 1, Reynolds analogy (Water+glycerin)

Silver Hollow glass (15micron diameter)

-1

-0.5

0

0.5

1

1.5

-0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6

Time (=>N=2Hz)

Vol

tage

(mV

)

Flow dynamics in LM Bifurcation.

• Experimental device :

For 60° and 90° bifurcation angles

Normal bifurcation Without stent

With stent before Kissing procedure

With stent lateral struts openProvisional stenting , proximal crossing

Flow dynamics in LM Bifurcation.

• Provisional stenting

Flow dynamics in LM Bifurcation.

• Natural bifurcation :• 60° Bifurcation : • 90° Bifurcation :

Low velocity gradient zones/ Low WSS

Flow dynamics in LM Bifurcation.Stent before kissing procedure

• 60° Bifurcation : • 90° Bifurcation :

RecirculationShadow area3D phenomenon

Flow dynamics in LM Bifurcation.

Stent provisional stenting • 60° Bifurcation : • 90° Bifurcation :

RecirculationShadow area3D phenomenon