Effects of clinico-pathological risk factors on in-vitro mechanical properties of human dilated ascending aorta

Anna Ferrara, Pasquale Totaro, Simone Morganti, Ferdinando Auricchio

Research output: Contribution to journalArticle

Abstract

Ascending aorta aneurysms (AsAA) are associated with a degeneration of the aortic wall tissue, which leads to changes in tissue mechanical properties. Risk factors for the development of the AsAA disease are recognized in patient age and gender, valve type, hypertension, diabetes mellitus, smoking history, and a prior diagnosis of Marfan syndrome. The present study aims to assess how such clinico-pathological factors can affect the mechanical properties of human dilated ascending aorta. Specimens of AsAA are excised from 68 patients who underwent elective AsAA surgical repair and stretched until rupture during the execution of uniaxial tensile tests. Experimental stress-stretch curves are used to determine tissue mechanical properties (stress and stretch at failure point and at transition point, low and high elastic modulus). Data are divided into groups according to region (anterior vs posterior), direction (circumferential vs longitudinal), and then according to age (young vs old), gender (male vs female), valve type (tricuspid aortic valve, TAV, vs bicuspid aortic valve, BAV), and presence of hypertension, diabetes mellitus, and/or Marfan syndrome (yes/no). Moreover, data are grouped according to the critical value of body mass index (BMI), maximum AsAA diameter, and aortic stiffness index (ASI), respectively. Finally, a non-parametric statistical analysis is performed to find possible significant differences and correlations between mechanical properties and clinico-pathological data. Our results confirm the anisotropy and heterogeneity of the AsAA tissue and highlight that ageing and hypertension make the AsAA tissue weaker and less extensible, whereas the valve type affects the tissue strength with higher values in BAV than in TAV patients. No effects of gender, critical BMI, critical maximum AsAA diameter, critical ASI, smoking status, and presence of diabetes mellitus, and Marfan syndrome are evidenced.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalJournal of the Mechanical Behavior of Biomedical Materials
Volume77
DOIs
Publication statusPublished - Jan 1 2018

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Keywords

  • Aneurysms
  • Ascending aorta
  • Clinico-pathological risk factors
  • Tissue mechanical properties
  • Uniaxial tensile tests

ASJC Scopus subject areas

  • Biomaterials
  • Biomedical Engineering
  • Mechanics of Materials

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