Effects of aortic root motion on wall stress in the Marfan aorta before and after personalised aortic root support (PEARS) surgery

Singh, Swati; Xu, Xiao Yun; Pepper, John; İzgi, Cemil; Treasure, Tom; Mohiaddin, Raad H.

doi:10.1016/j.jbiomech.2016.05.011

Cited by 24 publications

(27 citation statements)

References 18 publications

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“…Both effects of AR axial and in-plane motion on aortic responses were evaluated by imposing downward and in-plane displacement on proximal AA end. Similar with other researches [2, 9], the peak aortic von Mises and circumferential stress were always located at the superior artery branches. The AR traction was previously postulated to increase proximal AA transection risk by elevating its longitudinal stress [2, 9].…”

Section: Discussionsupporting

confidence: 88%

“…Similar with other researches [2, 9], the peak aortic von Mises and circumferential stress were always located at the superior artery branches. The AR traction was previously postulated to increase proximal AA transection risk by elevating its longitudinal stress [2, 9]. Therefore, the stress levels were also evaluated by respectively averaging the von Mises, circumferential and longitudinal stresses of the AA section 2 cm above the AR under different loading conditions (Table 2).…”

Section: Discussionsupporting

confidence: 88%

“…LS-Prepost (LSTC, Livermore, CA, USA) was used to discretize the aortic inner wall with 4-node shell elements, which were subsequently offset outward with a uniform thickness of 1.6 mm to generate the hexahedral elements for the aortic wall. The assumed uniform aortic thickness was compatible with the reported ranges in literature [14] and was also commonly performed as in previous works [2, 9]. The shell elements of the aortic inner wall were only used to generate the aortic wall brick elements only and not for the following simulations.…”

Section: Methodsmentioning

confidence: 99%

“…Aortic finite element (FE) models were previously used to evaluate the AR downward [2, 3, 9] and twisted [2, 3] motion effects on proximal AA stress levels. Studying the influences of AR in-plane movement is however limited.…”

Section: Introductionmentioning

confidence: 99%

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Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root

et al. 2019

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Background The axial motion of aortic root (AR) due to ventricular traction was previously suggested to contribute to ascending aorta (AA) dissection by increasing its longitudinal stress, but AR in-plane motion effects on stresses have never been studied. The objective is to investigate the contribution of AR in-plane motion to AA stress levels. Methods The AR in-plane motion was assessed on magnetic resonance imagining data from 25 healthy volunteers as the movement of the AA section centroid. The measured movement was prescribed to the proximal AA end of an aortic finite element model to investigate its influences on aortic stresses. The finite element model was developed from a patient-specific geometry using LS-DYNA solver and validated against the aortic distensibility. Fluid–structure interaction (FSI) approach was also used to simulate blood hydrodynamic effects on aortic dilation and stresses. Results The AR in-plane motion was 5.5 ± 1.7 mm with the components of 3.1 ± 1.5 mm along the direction of proximal descending aorta (PDA) to AA centroid and 3.0 ± 1.3 mm perpendicularly under the PDA reference system. The AR axial motion elevated the longitudinal stress of proximal AA by 40% while the corresponding increase due to in-plane motion was always below 5%. The stresses at proximal AA resulted approximately 7% less in FSI simulation with blood flow. Conclusions The AR in-plane motion was comparable with the magnitude of axial motion. Neither axial nor in-plane motion could directly lead to AA dissection. It is necessary to consider the heterogeneous pressures related to blood hydrodynamics when studying aortic wall stress levels. Electronic supplementary material The online version of this article (10.1186/s12938-019-0632-7) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root

et al. 2019

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“…The inclusion of the aortic root longitudinal strain in risk stratification has also been evoked in the past. A recent study by Guala et al (2019) reported the predictive value of aortic root longitudinal strain for aortic dilation and aortic events in Marfan syndrome patients, while several other studies have demonstrated the potential for aortic longitudinal deformation in the assessment of risk of dissection (Beller et al 2004;Singh et al 2016).…”

Section: Discussionmentioning

confidence: 99%

The effect of the elongation of the proximal aorta on the estimation of the aortic wall distensibility

Pagoulatou

Ferraro

Trachet

et al. 2020

Biomech Model Mechanobiol

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The compliance of the proximal aortic wall is a major determinant of cardiac afterload. Aortic compliance is often estimated based on cross-sectional area changes over the pulse pressure, under the assumption of a negligible longitudinal stretch during the pulse. However, the proximal aorta is subjected to significant axial stretch during cardiac contraction. In the present study, we sought to evaluate the importance of axial stretch on compliance estimation by undertaking both an in silico and an in vivo approach. In the computational analysis, we developed a 3-D finite element model of the proximal aorta and investigated the discrepancy between the actual wall compliance to the value estimated after neglecting the longitudinal stretch of the aorta. A parameter sensitivity analysis was further conducted to show how increased material stiffness and increased aortic root motion might amplify the estimation errors (discrepancies between actual and estimated distensibility ranging from − 20 to − 62%). Axial and circumferential aortic deformation during ventricular contraction was also evaluated in vivo based on MR images of the aorta of 3 healthy young volunteers. The in vivo results were in good qualitative agreement with the computational analysis (underestimation errors ranging from − 26 to − 44%, with increased errors reflecting higher aortic root displacement). Both the in silico and in vivo findings suggest that neglecting the longitudinal strain during contraction might lead to severe underestimation of local aortic compliance, particularly in the case of women who tend to have higher aortic root motion or in subjects with stiff aortas.

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Reproducibility of 3D thoracic aortic displacement from 3D cine balanced SSFP at 3 T without contrast enhancement

Merton,

Bosshardt,

Strijkers

et al. 2023

Magnetic Resonance in Med

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PurposeAortic motion has direct impact on the mechanical stresses acting on the aorta. In aortic disease, increased stiffness of the aorta may lead to decreased aortic motion over time, which could be a predictor for aortic dissection or rupture. This study investigates the reproducibility of obtaining 3D displacement and diameter maps quantified using accelerated 3D cine MRI at 3 T.MethodsA noncontrast‐enhanced, free‐breathing 3D cine sequence based on balanced SSFP and pseudo‐spiral undersampling with high spatial isotropic resolution was developed (spatial/temporal resolution [1.6 mm]3/67 ms). The thoracic aorta of 14 healthy volunteers was prospectively scanned three times at 3 T: twice on the same day and a third time 2 weeks later. Aortic displacement was calculated using iterative closest point nonrigid registration of manual segmentations of the 3D aorta at end‐systole and mid‐diastole. Interexamination and interobserver regional analysis of mean displacement for five regions of interest was performed using Bland–Altman analysis. Additionally, a complementary voxel‐by‐voxel analysis was done, allowing a more local inspection of the method.ResultsNo significant differences were found in mean and maximum displacement for any of the regions of interest for the interexamination and interobserver analysis. The maximum displacement measured in the lower half of the ascending aorta was 11.0 ± 3.4 mm (range: 3.0–17.5 mm) for the first scan. The smallest detectable change in mean displacement in the lower half of the ascending aorta was 3 mm.ConclusionDetailed 3D cine balanced SSFP at 3 T allows for reproducible quantification of systolic–diastolic mean aortic displacement within acceptable limits.

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Effects of aortic root motion on wall stress in the Marfan aorta before and after personalised aortic root support (PEARS) surgery

Cited by 24 publications

References 18 publications

Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root

Investigating heartbeat-related in-plane motion and stress levels induced at the aortic root

The effect of the elongation of the proximal aorta on the estimation of the aortic wall distensibility

Reproducibility of 3D thoracic aortic displacement from 3D cine balanced SSFP at 3 T without contrast enhancement

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