Predissection-derived geometric and distensibility indices reveal increased peak longitudinal stress and stiffness in patients sustaining acute type A aortic dissection: Implications for predicting dissection

Leonid Emerel; James Thunes; Trevor Kickliter; Marie Billaud; Julie A Phillippi; David A Vorp; Spandan Maiti; Thomas G Gleason

doi:10.1016/j.jtcvs.2018.10.116

Predissection-derived geometric and distensibility indices reveal increased peak longitudinal stress and stiffness in patients sustaining acute type A aortic dissection: Implications for predicting dissection

J Thorac Cardiovasc Surg. 2019 Aug;158(2):355-363. doi: 10.1016/j.jtcvs.2018.10.116. Epub 2018 Nov 3.

Authors

Leonid Emerel¹, James Thunes², Trevor Kickliter², Marie Billaud³, Julie A Phillippi⁴, David A Vorp⁵, Spandan Maiti², Thomas G Gleason⁶

Affiliations

¹ Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa.
² Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa.
³ Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa.
⁴ Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, Pa.
⁵ Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, Pa; Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pa.
⁶ Department of Cardiothoracic Surgery, University of Pittsburgh, Pittsburgh, Pa; Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pa; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pa; Center for Vascular Remodeling and Regeneration, University of Pittsburgh, Pittsburgh, Pa; Center for Thoracic Aortic Disease, University of Pittsburgh, Pittsburgh, Pa. Electronic address: gleasontg@upmc.edu.

Abstract

Objective: To assess ascending aortic distensibility and build geometry and distensibility-based patient-specific stress distribution maps in patients sustaining type A aortic dissection (TAAD) using predissection noninvasive imaging.

Methods: Review of charts from patients undergoing surgical repair of TAAD (n = 351) led to the selection of a subset population (n = 7) with 2 or more predissection computed tomography angiography scans and echocardiograms at least 1 year before dissection. Ascending aortic wall biomechanical properties (aortic strain, distensibility, and stiffness) were compared with age- and size-matched nondissected nonaneurysmal controls. Patient-specific aortic strain served as an input in aortic geometry-based simulated 3-dimensional reconstructions to generate longitudinal and circumferential wall stress maps. Inspection of perioperative dissection scans and intraoperative visual examination confirmed primary tear locations.

Results: Predissection echocardiography revealed ascending aortas of patients sustaining TAAD to exhibit decreased aortic wall strain (14.50 ± 1.13% vs 8.49 ± 1.08%; P < .01), decreased distensibility (4.26 ± 0.44 vs 2.39 ± 0.33 10^-6 cm²·dyne^-1; P < .01), increased stiffness (3.84 ± 0.24 vs 7.48 ± 1.05; P < .001), and increased longitudinal wall stress (246 ± 22 vs 172 ± 37 kPa; P < .01). There was no significant difference in circumferential wall stress. Predissection computed tomography angiography models revealed overlap between regions of increased longitudinal wall stress and primary tear sites.

Conclusions: Using predissection imaging, we identified increased stiffness and longitudinal wall stress in ascending aortas of patients with dissection. Patient-specific imaging-derived biomechanical property maps like these may be instrumental toward designing better prediction models of aortic dissection potential.

Keywords: aortic aneurysm; aortic biomechanical properties; aortic dissection; aortic wall stress.

MeSH terms

Aorta / pathology*
Aorta / physiopathology
Aortic Dissection / etiology*
Computed Tomography Angiography
Echocardiography
Female
Humans
Male
Middle Aged
Retrospective Studies
Risk Factors
Stress, Physiological
Vascular Stiffness*

Grants and funding

R01 HL109132/HL/NHLBI NIH HHS/United States