title: Extensibility and Distensibility of the Thoracic Aorta in Patients with Aneurysm.
abstract: OBJECTIVE
  Reference values of aortic deformation during the cardiac cycle can be valuable for the pre-operative planning of thoracic endovascular aortic repair (TEVAR) and for facilitating computational fluid dynamics. This study aimed to quantify normal aortic extensibility (longitudinal extension) and distensibility (radial expansion), as well as pulsatile strain, in a group of 10 (>60 years) individuals with abdominal or thoracic aortic aneurysms.
  
  
  METHODS
  ECG gated CT images of the thoracic aorta were reconstructed into virtual 3D models of aortic geometry. The centre lumen line length of the thoracic aorta and three longitudinal segments, and the aortic diameter and luminal areas of four radial intersections were extracted with a dedicated software script to calculate extensibility, longitudinal strain, distensibility, and circumferential area strain.
  
  
  RESULTS
  Mean extensibility and longitudinal strain of the entire thoracic aorta were 3.5 [1.3-6.8] × 10-3N-1, and 2.7 [1.0-4.5]%, respectively. Extensibility and longitudinal strain were most pronounced in the ascending aorta (20.6 [5.7-36.2] × 10-3N-1and 15.9 [6.6-31.9]%) and smallest in the descending aorta (4.4 [1.6-12.3] × 10-3N-1and 2.2 [0.7-4.7]%). Mean distensibility and circumferential area strain were most pronounced at the sinotubular junction (1.7 [0.5-2.9] × 10-3mmHg-1and 11.3 [3.3-18.5]%, respectively). Distensibility varied between 0.9 [0.3-2.5] × 10-3mmHg-1and 1.2 [0.3-3.3] × 10-3mmHg-1at the intersections in the aortic arch and descending aorta.
  
  
  CONCLUSIONS
  Pulsatile deformations in both longitudinal and circumferential directions are considerable throughout the thoracic aorta. These findings may have implications for pre-operative TEVAR planning and highlight the need for devices that can mimic the significant aortic longitudinal and circumferential strains.
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: H W L
authors.initials: HW
authors.lastname: de Beaufort
authors.affiliation: Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, Italy; Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands; Departments of Biomedical Engineering and Surgery, University of Michigan, Ann Arbor, USA.
authors.forename: F J H
authors.initials: FJ
authors.lastname: Nauta
authors.affiliation: Department of Civil Engineering and Architecture, University of Pavia, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Conti
authors.affiliation: CESNA Center for Advanced Numerical Simulations, Istituto Universitario di Studi Superiori di Pavia (IUSS), Pavia, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Cellitti
authors.affiliation: CESNA Center for Advanced Numerical Simulations, Istituto Universitario di Studi Superiori di Pavia (IUSS), Pavia, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Trentin
authors.affiliation: Department of Civil Engineering and Architecture, University of Pavia, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Faggiano
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: G H W
authors.initials: GH
authors.lastname: van Bogerijen
authors.affiliation: Departments of Biomedical Engineering and Surgery, University of Michigan, Ann Arbor, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Figueroa
authors.affiliation: Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: F L
authors.initials: FL
authors.lastname: Moll
authors.affiliation: Department of Vascular Surgery, University Medical Center Utrecht, The Netherlands.
authors.forename: J A
authors.initials: JA
authors.lastname: van Herwaarden
authors.affiliation: Department of Civil Engineering and Architecture, University of Pavia, Italy; CESNA Center for Advanced Numerical Simulations, Istituto Universitario di Studi Superiori di Pavia (IUSS), Pavia, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Auricchio
authors.affiliation: Thoracic Aortic Research Center, Policlinico San Donato IRCCS, University of Milan, Italy. Electronic address: santi.trimarchi@grupposandonato.it.
authors.forename: S
authors.initials: S
authors.lastname: Trimarchi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017544:Aortic Aneurysm, Abdominal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017545:Aortic Aneurysm, Thoracic / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001027:Aortography / Q000379:methods; D001696:Biomechanical Phenomena; D055424:Cardiac-Gated Imaging Techniques; D000072226:Computed Tomography Angiography; D003198:Computer Simulation; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D061330:Multidetector Computed Tomography; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D012189:Retrospective Studies; D013314:Stress, Mechanical
keywords: Abdominal aneurysm; Distensibility; Extensibility; Pulsatile flow; Thoracic aneurysm; Thoracic aorta