Aortic valve-mediated wall shear stress is heterogeneous and predicts regional aortic elastic fiber thinning in bicuspid aortic valve-associated aortopathy

The Journal of Thoracic and Cardiovascular Surgery

Pim van Ooij¹  David G. Guzzardi²  Katherine E. Olsen³  S. Chris Malaisrie⁴  Emilie Bollache⁵  Elena S. Di Martino⁶  Samaneh Sattari⁷ 

[1] Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, Ill;Department of Cardiac Sciences, Cumming School of Medicine, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada;Department of Civil Engineering, Schulich School of Engineering, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada;Department of Radiology, Academic Medical Center, Amsterdam, The Netherlands;Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Ill;Division of Surgery-Cardiac Surgery, Northwestern University, Bluhm Cardiovascular Institute, Chicago, Ill;Graduate Program in Biomedical Engineering, University of Calgary, Calgary, Alberta, Canada

关键词: bicuspid aortic valve;    aortopathy;    wall shear stress;    4D flow MRI;   

DOI  :  10.1016/j.jtcvs.2018.05.095

学科分类：心脏病和心血管学

来源: Mosby, Inc.

【 摘 要 】

ObjectivesThe objectives of this study were to investigate an association between the magnitude of flow-mediated aortic wall shear stress (WSS) and medial wall histopathology in patients with bicuspid aortic valve (BAV) with aortopathy.MethodsPatients with BAV (n = 27; 52 ± 15 years; 3 women; proximal thoracic aorta diameter = 4.4 ± 0.7 and 4.6 ± 0.5 cm) who underwent prophylactic aortic resection received preoperative 3-dimensional time-resolved phase-contrast magnetic resonance imaging with 3-dimensional velocity encoding to quantify WSS relative to a population of healthy age- and sex-matched tricuspid aortic valve control participants (n = 20). Quantitative histopathology was conducted on BAV aorta tissue samples resected at surgery (n = 93), and correlation was performed between elastic fiber thickness and in vivo aortic WSS as continuous variables. Validation of elastic fiber thickness was achieved by correlation relative to tissue stiffness determined using biaxial biomechanical testing (n = 22 samples).ResultsElastic fibers were thinner and WSS was higher along the greater curvature compared with other circumferential regions (vs anterior wall: P = .003 and P = .0001, respectively; lesser curvature: both P = .001). Increased regional WSS was associated with decreased elastic fiber thickness (r = −0.25; P = .02). Patient stratification with subanalysis showed an increase in the correlation between WSS and histopathology with aortic valve stenosis (r = −0.36; P = .002) and smaller aortic diameters (r = −0.39; P = .03). Elastic fiber thinning was associated with circumferential stiffness (r = −0.41; P = .06).ConclusionsFor patients with BAV, increased aortic valve-mediated WSS is significantly associated with elastic fiber thinning, particularly with aortic valve stenosis and in earlier stages of aortopathy. Elastic fiber thinning correlates with impaired tissue biomechanics. These novel findings further implicate valve-mediated hemodynamics in the progression of BAV aortopathy.

【 授权许可】

Unknown