Author + information
- Received June 23, 2016
- Accepted August 11, 2016
- Published online October 24, 2016.
- Erhan Tenekecioglu, MDa,
- Eric K.W. Poon, PhDb,
- Carlos Collet, MDc,
- Vikas Thondapu, MDb,d,
- Ryo Torii, PhDe,
- Christos V. Bourantas, MD, PhDf,g,
- Yaping Zeng, MD, PhDa,
- Yoshinobu Onuma, PhD, MDa,
- Andrew S.H. Ooi, PhDb,
- Patrick W. Serruys, PhD, MDa,h,∗ ( and )
- Peter Barlis, PhD, MDb,d
- aDepartment of Interventional Cardiology, Erasmus University Medical Center, Rotterdam, the Netherlands
- bDepartment of Mechanical Engineering, Melbourne School of Engineering, University of Melbourne, Melbourne, Australia
- cDepartment of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- dMelbourne Medical School, Faculty of Medicine, Dentistry & Health Sciences, University of Melbourne, Melbourne, Australia
- eDepartment of Mechanical Engineering, University College London, London, United Kingdom
- fDepartment of Cardiovascular Sciences, University College London, London, United Kingdom
- gDepartment of Cardiology, Barts Health NHS Trust, London, United Kingdom
- hImperial College, London, United Kingdom
- ↵∗Reprint requests and correspondence:
Dr. Patrick W. Serruys, Department of Cardiology, Erasmus MC, Thoraxcenter, Westblaak 98, 3012KM, Rotterdam, the Netherlands.
A 3.0 × 18 mm Absorb bioresorbable vascular scaffold (Abbott Vascular, Santa Clara, California) was implanted in the midsegment of the left anterior descending coronary artery of a patient with stable angina pectoris. Optical coherence tomography was performed following scaffold implantation (pullback speed 18 mm/s, acquisition rate 180 frames/s). Optical coherence tomographic images demonstrated a well-expanded and apposed scaffold. Patient-specific 3-dimensional geometry of the scaffolded lumen was generated using optical coherence tomography and coronary angiography. Computational fluid dynamics techniques were used to simulate pulsatile blood flow through 3-dimensional patient-specific finite volume mesh by solving Navier-Stokes equations. Blood was considered a non-Newtonian fluid, and a pulsatile flow profile was imposed in the inflow of the model. Shear-thinning blood rheology was simulated using the Quemada constitutive equation, which takes hematocrit and shear rate into account (1). Endothelial shear stress (ESS) at the lumen and scaffold surfaces was calculated as the product of local blood viscosity and near wall velocity gradient (2).
Increased ESS was noted at the strut surface and outer curve of the bend; low ESS (<0.5 Pa) was noted between successive stent hoops and the inner curve of the bend (Figures 1A to 1C). An internal view of the scaffold segment, across the gray line in Figure 1A, reveals microrecirculations (red arrows in Figure 1D) between stent hoops. Arterial curvature created a spiral velocity component (streamlines flowing from top to bottom of the vessel in Figure 1D), also called secondary flow (3).
As a result of skewed velocity profile along the bend (Figure 1C), microrecirculations were less pronounced at the outer curve but relatively larger at the inner curve of the bend (Figure 1E, Online Video 1). It has been hypothesized that such microrecirculations in the vicinity of struts are associated with lower shear rate zones that may become the nidus for thrombus formation (4). In vivo 3-dimensional optical coherence tomographic computational fluid dynamics modeling can be used to evaluate the implications of scaffold implantation on the local hemodynamic parameters, which may shed light on possible pathophysiological responses, such as thrombus formation and neointimal hyperplasia.
The authors would like to acknowledge the support of the Australian Research Councilhttp://dx.doi.org/10.13039/501100000923 for this research through ARC Linkage Project LP150100233.
For a supplemental video and legend, please see the online version of this article.
This research was supported by a Victorian Sciences Computational Initiative (VLSCI) grant number [VR0210] on its Peak Computing Facility at the University of Melbourne, an initiative of the Victoria Government, Australia. Dr. Serruys is a member of the international advisory board of Abbott Vascular. Dr. Onuma is a member of the international advisory board of Abbott Vascular. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Drs. Tenekecioglu and Poon contributed equally to this work.
- Received June 23, 2016.
- Accepted August 11, 2016.
- 2016 American College of Cardiology Foundation