In Vivo flow simulation after implantation

of BRS in coronary bifurcations

Yingguang Li1, Zehang Li2, Zhenyu Fei2, Jouke Dijkstra1,

Pieter Kitslaar1, Emil N. Holck3, Evald Høj Christiansen3, Johan H. C. Reiber1, Niels R. Holm3, Shengxian Tu2

1 Leiden University Medical Center, Leiden, The Netherlands

2 Shanghai Jiao Tong University, Shanghai, China

3 Aarhus University Hospital, Skejby, Aarhus, Denmark

Background

BRS on OCT

The role of shear stress distribution after BRS implantation in coronary bifurcations has not been completely understood, particular in the following regions:

- Bifurcation area

- Stented subsegment

Accurate modeling is crucial in the assessment of shear stress

Chatzizisis et al. JACC 2007

Computational fluid dynamics

CFD allows evaluation of local flow pattern and shear stress. The accuracy of CFD depends on the accuracy of boundary conditions:

- Geometric boundary(geometric model)

• ICA

• CTA

• IVUS

• OCT

Fusion

- Hemodynamic boundary

• Flow

• Pressure

• Resistance

Coronary tree and BRS reconstruction

Tree Model = OCT (main vessel) + 3D QCA (side branches)

Li et al. JACC 2015, 66:125-35

Bended oct

3D QCA

Segmented by QCU-CMS

fusion

Compare 2 tree models: one with BRS and one without

tree model with BRS (TMBRS)

tree model(TM)

Mesh

Computation shear stress

Velocity distribution WSS distribution

Carpet view comparison of WSS

Portion

Longitudinal: 0.15mm

Circumferential: 0.15mm

Difference

detailed analysis

Results for 10 patients from the BIFSORB studyCourtesy Niels Holm, Aarhus, Denmark

Results: whole segments which contain BRS

Average difference:0.35 (p < 0.0001)

Range: (-21.1 ; 142.4)

Results: stented subsegments

Average difference: 0.83 (p < 0.0001)

Range: (-21.1 ; 142.4)

Results: BRS area at side branch ostia

Average difference: 12.2 (p < 0.0001)

Range: (0.03; 142.4)

Conclusions and Discussion

• BRS implantation– Results in almost equal portions of evident positive difference

(34.3%) and evident negative difference (35.2%) at stented subsegments of the main vessel.

– Significantly increases the Shear Stress at BRS area in side branch ostia. 93% portions have SS values larger than 0.5 pa and average values is 12.2 pa, which means the impact of BRS implantation on the flow of side branches (especially at the ostia) at the covered segment is significant.

• Feasibility of QCA-OCT fusion– Accurate 3D anatomical reconstruction of both coronary artery and

BRS.

– Accurate hydrodynamic / biomechanical calculation

• Subsequent research– Focus on relation between SS and endothelialization of stent

– Dynamic CFD analysis

Pulsatile flow simulation

Acknowledgements:

Leiden University Medical CenterJohan H.C. ReiberJouke DijkstraPieter Kitslaar

Aarhus University HospitalNiels R. HolmEmil N. HolckEvald H.Christiansen

Shanghai Jiao Tong UniversityShengxian TuZehang LiZhenyu Fei

Acknowledgements:

• National Natural Science Foundation of China (grant number 31500797 and 81570456)

• National Key Research and Development Program of China (grant number 2016YFC0100500)

Contacted information:

Yingguang Li: yingguangli133@gmail.com

Shengxian Tu: sxtu@sjtu.edu.cn