Obtaining the biomechanical behavior of ascending aortic aneurysm via the use of novel speckle tracking echocardiography

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 153; no. 4; pp. 781 - 788
• Main Authors: Alreshidan, Mohammed, MD, MSc(C), Shahmansouri, Nastaran, MSc, Chung, Jennifer, MD, MSc, Lash, Vynka, FRCPC, Emmott, Alexander, MEng, Leask, Richard L., PhD, Lachapelle, Kevin, MD, FACS, FRCSC
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.2017
• Subjects: Aged; aneurysm; aorta; Aorta - diagnostic imaging; Aorta - physiopathology; Aorta - surgery; Aortic Aneurysm - diagnostic imaging; Aortic Aneurysm - physiopathology; Aortic Aneurysm - surgery; Biomechanical Phenomena; biomechanics; Cardiothoracic Surgery; echo speckle tracing; Echocardiography - methods; Echocardiography, Transesophageal; Female; Hemodynamics; Humans; Male; Middle Aged; Predictive Value of Tests; risk of rupture; Vascular Stiffness; β2; aneurysm; AoS; circumferential strain; left ventricle; risk of rupture; in vivo stiffness index; echo speckle tracing; LV; biomechanics; 2-dimensional; 2D; analysis of variance; ANOVA; TEE; aorta; transesophageal echocardiography
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/j.jtcvs.2016.11.056

Abstract Introduction 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. Methods 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: β 2 = ln ( S B P / D B P ) / A o S , 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. Results 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). Conclusions The use of speckle TEE appears to be a promising technique to estimate ex vivo mechanical properties of the ascending aortic tissue.