Strongly Coupled Morphological Features of Aortic Aneurysms Drive Intraluminal Thrombus

Bhagavan, Druv; Achille, Paolo Di; Humphrey, Jay D.

doi:10.1038/s41598-018-31637-6

Cited by 20 publications

(21 citation statements)

References 60 publications

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“…Bhagavan et al 47 computationally examined the roles of five key morphologic features of AAAs on ILT formation: AAA diameter, AAA length, axial position, tortuosity, and renal artery position. They concluded that the maximum diameter is a key determinant, with vortex flow structures having the potential to induce thrombogenicity and, therefore, ILT deposition.…”

Section: Mechanical Properties and Hemodynamics Of Iltmentioning

confidence: 99%

Intraluminal thrombus: Innocent bystander or factor in abdominal aortic aneurysm pathogenesis?

Boyd

2021

JVS-Vascular Science

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Background Abdominal aortic aneurysms (AAAs) represent a complex multifactorial hemodynamic, thrombotic, and inflammatory process that can ultimately result in aortic rupture and death. Despite improved screening and surgical management of AAAs, the mortality rates have remained high after rupture, and little progress has occurred in the development of nonoperative treatments. Intraluminal thrombus (ILT) is present in most AAAs and might be involved in AAA pathogenesis. The present review examined the latest clinical and experimental evidence for possible involvement of the ILT in AAA growth and rupture. Methods A literature review was performed after a search of the PubMed database from 2012 to June 2020 using the terms “abdominal aortic aneurysm” and “intraluminal thrombus.” Results The structure, composition, and hemodynamics of ILT formation and propagation were reviewed in relation to the hemostatic and proteolytic factors favoring ILT deposition. The potential effects of the ILT on AAA wall degeneration and rupture, including a review of the current controversies regarding the position, thickness, and composition of ILT, are presented. Although initially potentially protective against increased wall stress, increasing evidence has shown that an increased volume and greater age of the ILT have direct detrimental effects on aortic wall integrity, which might predispose to an increased rupture risk. Conclusions ILT does not appear to be an innocent bystander in AAA pathophysiology. However, its exact role remains elusive and controversial. Despite computational evidence of a possible protective role of the ILT in reducing wall stress, increasing evidence has shown that the ILT promotes AAA wall degeneration in humans and in animal models. Further research, with large animal models and with more chronic ILT is crucial for a better understanding of the role of the ILT in AAAs and for the potential development of targeted therapies to slow or halt AAA progression.

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Section: Mechanical Properties and Hemodynamics Of Iltmentioning

confidence: 99%

Intraluminal thrombus: Innocent bystander or factor in abdominal aortic aneurysm pathogenesis?

Boyd

2021

JVS-Vascular Science

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“…Generally, there are two approaches to investigate the correlation between morphology and flow: (a) use patient‐specific models and correlate morphological features with flow response, or (b) use idealized models where morphological features are parameterized, often combined with one or two patient‐specific geometries to confirm the results . On the one hand, patient‐specific models are realistic but would require an extensive database of segmented surfaces to isolate the effect of a single morphological feature in a multifactorial disease.…”

Section: Introductionmentioning

confidence: 99%

A framework for automated and objective modification of tubular structures: Application to the internal carotid artery

Bergersen

Kjeldsberg

Valen‐Sendstad

2020

Numer Methods Biomed Eng

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Patient-specific medical image-based computational fluid dynamics has been widely used to reveal fundamental insight into mechanisms of cardiovascular disease, for instance, correlating morphology to adverse vascular remodeling.However, segmentation of medical images is laborious, error-prone, and a bottleneck in the development of large databases that are needed to capture the natural variability in morphology. Instead, idealized models, where morphological features are parameterized, have been used to investigate the correlation with flow features, but at the cost of limited understanding of the complexity of cardiovascular flows. To combine the advantages of both approaches, we developed a tool that preserves the patient-specificness inherent in medical images while allowing for parametric alteration of the morphology. In our opensource framework morphMan we convert the segmented surface to a Voronoi diagram, modify the diagram to change the morphological features of interest, and then convert back to a new surface. In this paper, we present algorithms for modifying bifurcation angles, location of branches, cross-sectional area, vessel curvature, shape of bends, and surface roughness. We show qualitative and quantitative validation of the algorithms, performing with an accuracy exceeding 97% in general, and proof-of-concept on combining the tool with computational fluid dynamics. By combining morphMan with appropriate clinical measurements, one could explore the morphological parameter space and resulting hemodynamic response using only a handful of segmented surfaces, effectively minimizing the main bottleneck in image-based computational fluid dynamics. K E Y W O R D S

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“…In the field of abdominal aortic aneurysms, although a different disease, aneurysm morphology and hemodynamics have been linked to intraluminal thrombus formation which has been identified as one of the drivers of aortic aneurysm progression. 20,21 Furthermore, hemodynamic and morphological factors, in combination with clinical data and shape of the intra-luminal thrombus, have been proposed as predictors of aortic aneurysm growth using data from longitudinally followed abdominal aortic aneurysms. 22 In contrast, intra-aneurysmal thrombus is rare in cerebral aneurysms and it mostly observed in large or giant aneurysms (>25 mm), and the mechanisms for their evolution remains unclear.…”

Section: Introductionmentioning

confidence: 99%

Analysis of hemodynamic changes from aneurysm inception to large sizes

Ashkezari

Mut

Chung

et al. 2020

Numer Methods Biomed Eng

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While previous studies have identified many risk factors for the progression and rupture of cerebral aneurysms, the changes in aneurysm flow characteristics during its evolution are not fully understood. This work analyzes the changes in the aneurysm hemodynamic environment from its initial development to later stages when the aneurysm has substantially enlarged. A total of 88 aneurysms at four locations were studied with image based computational fluid dynamics (CFD). Two synthetic sequences representing the aneurysm geometry at three earlier stages were generated by shrinking the aneurysm sac while keeping the neck fixed or shrinking the neck simultaneously. The flow conditions were then quantitatively compared between these two modes of evolution. As aneurysms enlarged, the inflow rate increased in growing neck sequences, but decreased in fixed neck sequences. The inflow jet became more concentrated in both sequences. The mean aneurysm flow velocity and wall shear stress decreased in both sequences, but they decreased faster in enlarging aneurysms if the neck was fixed. Additionally, the intra‐aneurysmal flows became more complex and more unstable, wall shear stress distribution became more oscillatory, and the area under low wall shear stress increased for both sequences. The evolution of flow characteristics of aneurysms with fixed and growing necks are different. The observed trends suggest that fixed neck aneurysms may evolve towards a flow environment characteristic of stable aneurysms faster than aneurysms with growing necks, which could also evolve towards a more disfavorable environment.

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Strongly Coupled Morphological Features of Aortic Aneurysms Drive Intraluminal Thrombus

Cited by 20 publications

References 60 publications

Intraluminal thrombus: Innocent bystander or factor in abdominal aortic aneurysm pathogenesis?

Intraluminal thrombus: Innocent bystander or factor in abdominal aortic aneurysm pathogenesis?

A framework for automated and objective modification of tubular structures: Application to the internal carotid artery

Analysis of hemodynamic changes from aneurysm inception to large sizes

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