title: Impact of thoracic endovascular aortic repair on radial strain in an ex vivo porcine model.
abstract: To quantify the impact of thoracic endovascular aortic repair (TEVAR) on radial aortic strain with the aim of elucidating stent-graft-induced stiffening and complications.
  
  
  
  Twenty fresh thoracic porcine aortas were connected to a mock circulatory loop driven by a centrifugal flow pump. A high-definition camera captured diameters at five different pressure levels (100, 120, 140, 160, and 180 mmHg), before and after TEVAR. Three oversizing groups were created: 0-9% ( n  = 7), 10-19% ( n  = 6), and 20-29% ( n  = 6). Radial strain (or deformation) derived from diameter amplitude divided by baseline diameter at 100 mmHg. Uniaxial tensile testing evaluated Young's moduli of the specimens.
  
  
  
  Radial strain was reduced after TEVAR within the stented segment by 49.4 ± 24.0% ( P  < 0.001). As result, a strain mismatch was observed between the stented segment and the proximal non-stented segment (7.0 ± 2.5% vs 11.8 ± 3.9%, P  < 0.001), whereas the distal non-stented segment was unaffected ( P  = 0.99). Stent-graft oversizing did not significantly affect the amount of strain reduction ( P  = 0.30). Tensile testing showed that the thoracic aortas tended to be more elastic proximally than distally ( P  = 0.11).
  
  
  
  TEVAR stiffened the thoracic aorta by 2-fold. Such segmental stiffening may diminish the Windkessel function considerably and might be associated with TEVAR-related complications, including stent-graft-induced dissection and aneurysmal dilatation. These data may have implications for future stent-graft design, in particular for TEVAR of the highly compliant proximal thoracic aorta.
authors.affiliation: Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, Italy.|Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: Foeke J H
authors.initials: FJH
authors.lastname: Nauta
authors.affiliation: Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, Italy.|Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: Hector W L
authors.initials: HWL
authors.lastname: de Beaufort
authors.affiliation: Department of Civil Engineering and Architecture, Beta-lab, University of Pavia, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Conti
authors.affiliation: Department of Civil Engineering and Architecture, Beta-lab, University of Pavia, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Marconi
authors.affiliation: Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, Italy.|Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: Arnoud V
authors.initials: AV
authors.lastname: Kamman
authors.affiliation: Department of Civil Engineering and Architecture, Beta-lab, University of Pavia, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Ferrara
authors.affiliation: Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: Joost A
authors.initials: JA
authors.lastname: van Herwaarden
authors.affiliation: Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: Frans L
authors.initials: FL
authors.lastname: Moll
authors.affiliation: Department of Civil Engineering and Architecture, Beta-lab, University of Pavia, Italy.
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Auricchio
authors.affiliation: Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, Italy.
authors.forename: Santi
authors.initials: S
authors.lastname: Trimarchi
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000503:physiopathology / Q000601:surgery*; D001807:Blood Vessel Prosthesis; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D004195:Disease Models, Animal; D004548:Elasticity; D057510:Endovascular Procedures / Q000009:adverse effects / Q000379:methods*; D015588:Observer Variation; D015203:Reproducibility of Results; D015607:Stents; D013314:Stress, Mechanical; D034421:Sus scrofa; D013552:Swine; D013718:Tensile Strength
keywords: Aortic strain ; Stent-graft ; TEVAR ; Thoracic aorta ; Uniaxial tensile testing