title: Obtaining the biomechanical behavior of ascending aortic aneurysm via the use of novel speckle tracking echocardiography.
abstract: Ex vivo measurement of ascending aortic biomechanical properties may help understand the risk for rupture or dissection of dilated ascending aortas. A validated in vivo method that can predict aortic biomechanics does not exist. Speckle tracking transesophageal echocardiography (TEE) has been used to measure ventricular stiffness; we sought to determine whether speckle TEE could be adapted to estimate aortic stiffness in vivo and compare these findings with those obtained by ex vivo tissue measurements.
  
  
  
  A total of 17 patients undergoing ascending aortic resection were recruited to with a mean aortic diameter was 56.16 ± 15 mm. Intraoperative speckle TEE tracking analysis was used to calculate aortic stiffness index using the following equation: β2=ln(SBP/DBP)/AoS, where β2 is the stiffness index; SBP is systolic blood pressure; DBP is diastolic blood pressure; and AoS is the circumferential strain. Ex vivo stiffness was obtained by mechanical tissue testing according to previously described methods. The aortic ring at the pulmonary trunk was divided into 4 equal quadrants.
  
  
  
  The in vivo stiffness index for the inner curvature, anterior wall, outer curvature, and posterior wall were 0.0544 ± 0.0490, 0.0295 ± 0.0199, 0.0411 ± 0.0328, and 0.0502 ± 0.0320, respectively. The mean ex vivo 25% apparent stiffness for inner curvature, anterior wall, outer curvature, and posterior wall were 0.0616 ± 0.0758 MPa, 0.0352 ± 0.00992 MPa, 0.0405 ± 0.0199 MPa, and 0.0327 ± 0.0106 MPa, respectively. The patient-matched ex vivo 25% apparent stiffness and in vivo stiffness index were not significantly different (P = .8617, 2-way analysis of variance with repeated measures).
  
  
  
  The use of speckle TEE appears to be a promising technique to estimate ex vivo mechanical properties of the ascending aortic tissue.
authors.affiliation: Department of Cardiac Surgery, McGill University, Montreal, Quebec, Canada; King Salman Heart Center, King Fahad Medical City, Riyadh, Saudi Arabia.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Alreshidan
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada.
authors.forename: Nastaran
authors.initials: N
authors.lastname: Shahmansouri
authors.affiliation: Department of Cardiac Surgery, McGill University, Montreal, Quebec, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Chung
authors.affiliation: Department of Anesthesia, McGill University, Montreal, Quebec, Canada.
authors.forename: Vynka
authors.initials: V
authors.lastname: Lash
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada.
authors.forename: Alexander
authors.initials: A
authors.lastname: Emmott
authors.affiliation: Department of Chemical Engineering, McGill University, Montreal, Quebec, Canada.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Leask
authors.affiliation: Department of Cardiac Surgery, McGill University, Montreal, Quebec, Canada. Electronic address: kevin.lachapelle@mcgill.ca.
authors.forename: Kevin
authors.initials: K
authors.lastname: Lachapelle
mesh_terms: D000368:Aged; D001011:Aorta / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D001014:Aortic Aneurysm / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D001696:Biomechanical Phenomena; D004452:Echocardiography / Q000379:methods*; D017548:Echocardiography, Transesophageal; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D059289:Vascular Stiffness
keywords: aneurysm; aorta; biomechanics; echo speckle tracing; risk of rupture