Effect of vessel tortuosity on stress concentration at the distal stent-vessel interface:Possible link with new entry formation through biomechanical simulation
Document Type
Article
Publication Date
8-1-2021
Abstract
A computational approach is used to investigate potential risk factors for distal stent graft-induced new entry (dSINE) in aortic dissection (AD) patients. Patient-specific simulations were performed based on computed tomography images acquired from six AD patients (three dSINE and three non-dSINE) to analyze the correlation between anatomical characteristics and stress/strain distributions. Sensitivity analysis was carried out using idealized models to independently assess the effect of stent graft length, stent tortuosity and wedge apposition angle at the landing zone on key biomechanical variables. Mismatch of biomechanical properties between the stented and nonstented regions led to high stress at the distal stent graft-vessel interface in all patients, as well as shear strain in the neighboring region, which coincides with the location of tear formation. Stress was observed to increase with the increase of stent tortuosity (from 263 kPa at a tortuosity angle of 50 deg to 313 kPa at 30 deg). It was further amplified by stent graft landing at the inflection point of a curve. Malapposition of the stent graft led to an asymmetrical segment within the aorta, therefore changing the location and magnitude of the maximum von Mises stress substantially (up to +25.9% with a +25 deg change in the distal wedge apposition angle). In conclusion, stent tortuosity and wedge apposition angle serve as important risk predictors for dSINE formation in AD patients.
Keywords
Distal stent graft-induced new entry, Aortic dissection, Thoracic endovascular aortic repair, Wedge apposition angle, Tortuosity angle, Stent tortuosity index
Divisions
fac_med
Funders
Royal Society Newton Advanced Fellowship[NA170094],Universiti Malaysia Pahang[RDU1803120]
Publication Title
Journal of Biomechanical Engineering-Transactions of the ASME
Volume
143
Issue
8
Publisher
ASME
Publisher Location
TWO PARK AVE, NEW YORK, NY 10016-5990 USA