title: Vasomotor Function Comparative Assessment at 1 and 2 Years Following Implantation of the Absorb Everolimus-Eluting Bioresorbable Vascular Scaffold and the Xience V Everolimus-Eluting Metallic Stent in Porcine Coronary Arteries: Insights From In Vivo Angiography, Ex Vivo Assessment, and Gene Analysis at the Stented/Scaffolded Segments and the Proximal and Distal Edges.
abstract: OBJECTIVE
  The purpose of this study was to assess and compare in vivo the restoration of vasomotor function following Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) and metallic Xience V (XV) (Abbott Vascular, Santa Clara, California) stent implantations in porcine coronary arteries at 1 and 2 years.
  
  
  BACKGROUND
  Drug-eluting metallic coronary stents induce sustained vasomotor dysfunction, and preliminary observations from arteries with bioresorbable scaffolds have indicated partially restored vasoreactivity.
  
  
  METHODS
  A total of 15 Absorb BVS (3.0 × 18.0 mm) and 14 XV (3.0 × 18.0 mm or 3.0 × 12.0 mm) stents were randomly implanted in the main coronaries of 12 nonatherosclerotic swine. The effect of implant on vasomotor performance (constrictive and expansive) was measured in the stented/scaffolded segments and the 5-mm proximal and distal adjacent segments in vivo by angiography assessing mean luminal diameter changes following infusion of vasoactive agents at 1 year (n = 6) and 2 years (n = 6) as well as ex vivo at 2 years using a tissue chamber apparatus. Endothelial cell function and smooth muscle cell phenotype gene marker levels were evaluated with quantitative real-time polymerase chain reaction.
  
  
  RESULTS
  The scaffolded Absorb BVS segments showed fully restored constrictive response compared with XV implanted vessels at 1 year: -24.30 ± 14.31% versus -1.79 ± 6.57% (p < 0.004) and at 2 years: -28.13 ± 14.60% versus -3.90 ± 6.44% (p < 0.004). The early restoration of vasomotor function within the scaffolded segments reached a peak at 1 year and did not significantly change up to 2 years. The vasoactive responses of Absorb BVS-implanted vessels within the scaffolded segments were similar to those observed within the proximal and distal edge segments at both time points. Conversely, the stented XV segments demonstrated significantly impaired constrictive response compared with the distal XV edges at 1 year: -1.79 ± 6.57% versus -21.89 ± 7.17% (p < 0.0002) and at 2 years: -3.90 ± 6.44% versus -21.93 ± 15.60% (p < 0.03). Ex vivo assessment of contraction induced by PGF2α and relaxation induced by substance P of isolated BVS segments compared with XV-treated segments generated greater contraction force of 3.94 ± 0.97 g versus 1.83 ± 1.03 g (p < 0.05), and endothelial-dependent relaxation reached 35.91 ± 24.74% versus 1.20 ± 3.79% (p < 0.01). Quantitative real-time polymerase chain reaction gene analysis at 2 years demonstrated increased Connexin 43 messenger ribonucleic acid levels of Absorb BVS-treated vessels compared with XV-treated vessels: 1.92 ± 0.23 versus 0.77 ± 12 (p < 0.05).
  
  
  CONCLUSIONS
  Absorb BVS-implanted coronary arteries demonstrate early functional restoration of the scaffolded and adjacent segments at 1 year, which is preserved up to 2 years.
authors.affiliation: Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Bill D
authors.initials: BD
authors.lastname: Gogas
authors.affiliation: Abbott Vascular, Santa Clara, California.
authors.forename: James J
authors.initials: JJ
authors.lastname: Benham
authors.affiliation: Abbott Vascular, Santa Clara, California.
authors.forename: Steve
authors.initials: S
authors.lastname: Hsu
authors.affiliation: Abbott Vascular, Santa Clara, California.
authors.forename: Alexander
authors.initials: A
authors.lastname: Sheehy
authors.affiliation: Louisiana State University Health Sciences Center, New Orleans, Louisiana.
authors.forename: David J
authors.initials: DJ
authors.lastname: Lefer
authors.affiliation: Louisiana State University Health Sciences Center, New Orleans, Louisiana.
authors.forename: Traci T
authors.initials: TT
authors.lastname: Goodchild
authors.affiliation: Louisiana State University Health Sciences Center, New Orleans, Louisiana.
authors.forename: David J
authors.initials: DJ
authors.lastname: Polhemus
authors.affiliation: Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Yasir H
authors.initials: YH
authors.lastname: Bouchi
authors.affiliation: Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Olivia Y
authors.initials: OY
authors.lastname: Hung
authors.affiliation: Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia; Gangneung Asan Hospital, Ulsan University College of Medicine, Ulsan, South Korea.
authors.forename: Sang-Yong
authors.initials: SY
authors.lastname: Yoo
authors.affiliation: Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Udit
authors.initials: U
authors.lastname: Joshi
authors.affiliation: Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
authors.forename: Don P
authors.initials: DP
authors.lastname: Giddens
authors.affiliation: Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia; Department of Mathematics and Computer Science, Emory University, Atlanta, Georgia.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Veneziani
authors.affiliation: Emory Clinical Cardiovascular Research Institute, Department of Medicine, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Arshed
authors.initials: A
authors.lastname: Quyyumi
authors.affiliation: Abbott Vascular, Santa Clara, California.
authors.forename: Richard
authors.initials: R
authors.lastname: Rapoza
authors.affiliation: Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia; Saint Joseph's Heart and Vascular Institute, Atlanta, Georgia.
authors.forename: Spencer B
authors.initials: SB
authors.lastname: King
authors.affiliation: Andreas Gruentzig Cardiovascular Center, Division of Cardiology, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Emory Cardiovascular Imaging & Biomechanics Core Laboratory, Emory University School of Medicine, Atlanta, Georgia. Electronic address: hsamady@emory.edu.
authors.forename: Habib
authors.initials: H
authors.lastname: Samady
mesh_terms: D000818:Animals; D062906:Cardiac Catheters; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D020099:Coated Materials, Biocompatible; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D054855:Drug-Eluting Stents; D000068338:Everolimus / Q000008:administration & dosage*; D005786:Gene Expression Regulation; D066298:In Vitro Techniques; D008670:Metals; D023421:Models, Animal; D062645:Percutaneous Coronary Intervention / Q000009:adverse effects / Q000295:instrumentation*; D010641:Phenotype; D060888:Real-Time Polymerase Chain Reaction; D020127:Recovery of Function; D013552:Swine; D013556:Swine, Miniature; D013997:Time Factors; D014661:Vasoconstriction / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D002317:Cardiovascular Agents; D020099:Coated Materials, Biocompatible; D008670:Metals; D000068338:Everolimus
keywords: bioresorbable scaffolds; metal stents; porcine model; vasomotor function