title: Assessment of the hemodynamic characteristics of Absorb BVS in a porcine coronary artery model.
abstract: OBJECTIVE
  Local hemodynamic changes are one of the main factors that determine the vessel wall biological response after stent/scaffold implantation. Computational fluid dynamic studies provide an opportunity to investigate the rheological effects of implanted stent/scaffold. The aim of this study was to assess the local hemodynamic microenvironment in scaffolded segments in porcine coronary models.
  
  
  METHODS
  In six epicardial coronary arteries of healthy mini-pigs, six Absorb bioresorbable vascular scaffolds (Absorb BVS) were implanted. Optical coherence tomography(OCT) was performed after scaffold implantation and the images were fused with the angiographic data to reconstruct the three-dimensional coronary artery anatomy. Blood flow simulations were performed, and endothelial shear stress(ESS) distribution was estimated for each scaffolded segment. In a linear mixed-effect model, the contributing factors for low (<1.0Pa) ESS levels were assessed. At 30-day post-implantation, histopathological assessment was performed at 2 scaffolds.
  
  
  RESULTS
  In scaffolded segments, the median ESS was 0.57 (IQR: 0.29-0.99) Pa. In linear mixed-effect analysis, cross-section area was associated with low shear stress levels. In scaffolded segments, the percentage of the recirculation zone per scaffolded luminal surface was 3.26±2.07%. At 30-day histopathological assessment of implanted vessel segments revealed minimal injury score, minimal neointimal inflammation and minimal adventitial inflammation scores with moderate endothelial coverage. Fibrin accumulation was seen at 95.69±2.47% of the struts.
  
  
  CONCLUSIONS
  The thick rectangular strut design of the Absorb BVS incited flow disruptions with low shear stress inducing fibrin accumulation. CFD assessment can be used to guide improvements in the scaffold design for a more "hemo-compatible" geometry.
authors.affiliation: Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands.
authors.forename: Erhan
authors.initials: E
authors.lastname: Tenekecioglu
authors.affiliation: Department of Mechanical Engineering, University College London, London, United Kingdom.
authors.forename: Ryo
authors.initials: R
authors.lastname: Torii
authors.affiliation: Department of Cardiology, University College of London Hospitals, London, United Kingdom.
authors.forename: Christos
authors.initials: C
authors.lastname: Bourantas
authors.affiliation: Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abdelghani
authors.affiliation: Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands.
authors.forename: Rafael
authors.initials: R
authors.lastname: Cavalcante
authors.affiliation: Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Sotomi
authors.affiliation: Department of Cardiology, University College of London Hospitals, London, United Kingdom.
authors.forename: Tom
authors.initials: T
authors.lastname: Crake
authors.affiliation: Manli Cardiology, Singapore, Singapore.
authors.forename: Solomon
authors.initials: S
authors.lastname: Su
authors.affiliation: Department of Internal Medicine, Faculty of Medicine, Dr. Cipto Mangunkusumo and Medistra Hospitals, University of Indonesia, Jakarta, Indonesia.
authors.forename: Teguh
authors.initials: T
authors.lastname: Santoso
authors.affiliation: Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Onuma
authors.affiliation: Department of Interventional Cardiology, Erasmus University Medical Center, Thoraxcenter, Rotterdam, The Netherlands; Imperial College, London, United Kingdom. Electronic address: patrick.w.j.c.serruys@pwserruys.com.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D019917:Blood Vessel Prosthesis Implantation / Q000379:methods; D016009:Chi-Square Distribution; D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000601:surgery; D004195:Disease Models, Animal; D006439:Hemodynamics / Q000502:physiology*; D058426:Neointima / Q000473:pathology; D062645:Percutaneous Coronary Intervention / Q000379:methods*; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013552:Swine; D013556:Swine, Miniature; D054457:Tissue Scaffolds; D041623:Tomography, Optical Coherence
keywords: Bioresorbable scaffold; Computational fluid dynamic; Endothelial shear stress