title: Biaxial rupture properties of ascending thoracic aortic aneurysms.
abstract: Although hundreds of samples obtained from ascending thoracic aortic aneurysms (ATAA) of patients undergoing elective surgical repair have already been characterized biomechanically, their rupture properties were always derived from uniaxial tensile tests. Due to their bulge shape, ATAAs are stretched biaxially in vivo. In order to understand the biaxial rupture of ATAAs, our group developed a novel methodology based on bulge inflation and full-field optical measurements. The objective of the current paper is threefold. Firstly, we will review the failure properties (maximum stress, maximum stretch) obtained by bulge inflation testing on a cohort of 31 patients and compare them with failure properties obtained by uniaxial tension in a previously published study. Secondly, we will investigate the relationship between the failure properties and the age of patients, showing that patients below 55years of age display significantly higher strength. Thirdly, we will define a rupture risk based on the extensibility of the tissue and we will show that this rupture risk is strongly correlated with the physiological elastic modulus of the tissue independently of the age, ATAA diameter or the aortic valve phenotype of the patient.
  
  
  
  Despite their medical importance, rupture properties of ascending thoracic aortic aneurysms (ATAA) subjected to biaxial tension were inexistent in the literature. In order to address this lack, our group developed a novel methodology based on bulge inflation and full-field optical measurements. Here we report rupture properties obtained with this methodology on 31 patients. It is shown for the first time that rupture occurs when the stretch applied to ATAAs reaches the maximum extensibility of the tissue and that this maximum extensibility correlates strongly with the elastic properties. The outcome is a better detection of at-risk individuals for elective surgical repair.
authors.affiliation: Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, SAINBIOSE, F-42023 Saint Etienne, France; INSERM, U1059, F-42000 Saint Etienne, France; Université de Lyon, SAINBIOSE, F-42000 Saint Etienne, France; University Hospital of Saint-Etienne, Department of Cardiovascular Surgery, F-42055 Saint-Etienne cedex 2, France. Electronic address: ambroise.duprey@gmail.com.
authors.forename: Ambroise
authors.initials: A
authors.lastname: Duprey
authors.affiliation: Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, SAINBIOSE, F-42023 Saint Etienne, France; INSERM, U1059, F-42000 Saint Etienne, France; Université de Lyon, SAINBIOSE, F-42000 Saint Etienne, France. Electronic address: olfa.trabelsi1979@gmail.com.
authors.forename: Olfa
authors.initials: O
authors.lastname: Trabelsi
authors.affiliation: University Hospital of Saint-Etienne, Department of Cardiovascular Surgery, F-42055 Saint-Etienne cedex 2, France. Electronic address: marco.vola@-etienne.fr.
authors.forename: Marco
authors.initials: M
authors.lastname: Vola
authors.affiliation: INSERM, U1059, F-42000 Saint Etienne, France; Université de Lyon, SAINBIOSE, F-42000 Saint Etienne, France; University Hospital of Saint-Etienne, Department of Cardiovascular Surgery, F-42055 Saint-Etienne cedex 2, France. Electronic address: j.pierre.favre@chu-st-etienne.fr.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Favre
authors.affiliation: Ecole Nationale Supérieure des Mines de Saint-Etienne, CIS-EMSE, SAINBIOSE, F-42023 Saint Etienne, France; INSERM, U1059, F-42000 Saint Etienne, France; Université de Lyon, SAINBIOSE, F-42000 Saint Etienne, France. Electronic address: avril@emse.fr.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Avril
mesh_terms: D000328:Adult; D000368:Aged; D017545:Aortic Aneurysm, Thoracic / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D001019:Aortic Rupture / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D001696:Biomechanical Phenomena; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D013314:Stress, Mechanical; D013718:Tensile Strength; D055815:Young Adult
keywords: Aneurysm; Bulge inflation test; Extensibility; Human thoracic aorta; Rupture properties