Biochemomechanics of Intraluminal Thrombus in Abdominal Aortic Aneurysms

Wilson, John S.; Virag, Lana; Achille, Paolo Di; Karšaj, Igor; Humphrey, Jay D.

doi:10.1115/1.4023437

Cited by 88 publications

(106 citation statements)

References 132 publications

(256 reference statements)

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“…It is possible that in our study, we did not have sufficient statistical power to detect a difference in PWV or aneurysm diameter between the stable AAA and unstable AAA groups. In previous EXPERIMENTAL STUDIES: Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging Nandlall and Konofagou studies (19,31), investigators showed that aneurysm formation in the murine angiotensin II model is preceded by the formation of fissures in the wall of the aorta. Incomplete remodeling of the wall after the appearance of a fissure could result in structural weaknesses that remain in the saccular wall, thereby rendering rupture more likely.…”

Section: Experimental Studies: Assessing the Stability Of Aortic Aneumentioning

confidence: 99%

Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging

Nandlall¹,

Konofagou²

2016

Radiology

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Purpose:To assess whether the stability of murine aortic aneurysms is associated with the homogeneity of pulse wave propagation within the saccular wall. Materials and Methods:All animal procedures were approved by the institutional Animal Care and Use Committee. Apolipoprotein E and tissue inhibitor of metalloproteinases-1 knockout mice (n = 26) were infused with angiotensin II by using subcutaneously implanted osmotic pumps, with an additional control mouse used for histologic examination (n = 1). Pulse wave imaging (PWI) was performed just before infusion and 15 days after infusion by using 40-MHz ultrasonography at 8000 frames per second (with electrocardiographic gating). Aneurysm appearance on B-mode images was monitored every 2-3 days for 30 days. On the basis of B-mode images obtained after 30 days, aneurysms were deemed to have been unstable if they had ruptured; otherwise, they were deemed stable. Statistical significance was assessed by using two-tailed t tests. Results:In normal aortas, the pulse waves propagated at relatively constant velocities (mean 6 standard deviation, 2.8 m/sec 6 0.9). Fifteen days after infusion, all mice had developed aneurysms, with significant (P , .001/12) changes in maximum anterior-posterior diameter (increase of 54.9% 6 2.5) and pulse wave velocity (PWV) (decrease of 1.3 m/ sec 6 0.8). While there was no significant difference in these parameters (P = .45 for diameter and P = .55 for PWV) between stable aneurysms (n = 12) and unstable aneurysms (n = 14), the standard deviation of the highresolution PWV was significantly higher (P , .001/12) in unstable aneurysms (5.7 m/sec 6 1.6) than in stable ones (3.2 m/sec 6 0.9). Conclusion:High-resolution PWI was used to measure the local homogeneity of pulse wave propagation within the saccular wall, which is lower in unstable aneurysms than in stable ones. Hence, if proven to add additional information beyond size and appearance in human studies, PWI could potentially be used to assess the stability of aneurysms by providing information that is complementary to the anatomic data obtained with conventional B-mode imaging.q RSNA, 2016

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Section: Experimental Studies: Assessing the Stability Of Aortic Aneumentioning

confidence: 99%

Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging

Nandlall¹,

Konofagou²

2016

Radiology

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“…Over 75% of these lesions contain an intraluminal thrombus (ILT), which, in many cases, fills the lesion and yields a lumen of nearly normal size despite the extreme dilatation of the aortic wall. There remains a significant controversy over the precise roles an ILT may play in the enlargement and potential rupture of these aneurysms, but it appears that thrombus is important both biomechanically and biochemically [1][2][3]. There is, therefore, a pressing need to understand better the conditions that lead to the formation of an ILT within these potentially life-threatening lesions.…”

Section: Introductionmentioning

confidence: 99%

A haemodynamic predictor of intraluminal thrombus formation in abdominal aortic aneurysms

et al. 2014

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Intraluminal thrombus (ILT) is present in over 75% of all abdominal aortic aneurysms (AAAs) and probably contributes to the complex biomechanics and pathobiology of these lesions. A reliable predictor of thrombus formation in enlarging lesions could thereby aid clinicians in treatment planning. The primary goal of this work was to identify a new phenomenological metric having clinical utility that is motivated by the hypothesis that two basic haemodynamic features must coincide spatially and temporally to promote the formation of a thrombus on an intact endothelium-platelets must be activated within a shear flow and then be presented to a susceptible endothelium. Towards this end, we propose a new thrombus formation potential (TFP) that combines information on the flow-induced shear history experienced by blood-borne particles that come in close proximity to the endothelium with information on both the time-averaged wall shear stress (WSS) and the oscillatory shear index (OSI) that locally affect the endothelial mechanobiology. To illustrate the possible utility of this new metric, we show computational results for 10 carotid

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“…Complex hemodynamics and flow stagnation are often associated with prothrombotic conditions. For example, intraluminal thrombus in abdominal aortic aneurysm (AAA) [57,54] complicates disease progression, and is thought to be strongly coupled to flow stagnation and recirculation. The chaotic flow field in AAAs [3] leads to complex WSS distributions [4] and interesting near-wall flow structures [1].…”

Section: Introductionmentioning

confidence: 99%

Wall shear stress exposure time: a Lagrangian measure of near-wall stagnation and concentration in cardiovascular flows

Arzani

Gambaruto

Chen

et al. 2016

Biomech Model Mechanobiol

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms suitable in regions of complex hemodynamics that are traditionally difficult to quantify, yet encountered in many disease scenarios. Keywords: advection-diffusion; blood flow; hemodynamics; near-wall transport; residence time; shear stress; p. 2 IntroductionBiomechanical interactions between blood flow and the vessel wall are central to the initiation and progression of most cardiovascular diseases. Indeed, the majority of computational and experimental investigations into blood flow seek to understand how local flow mechanics relates to disease progression in or on the vessel wall. Blood flow conditions in diseased vessels are usually spatially and temporally complex and are challenging to characterize [51,50], even without reference to the coupled biochemical or biophysical processes driving disease progression. Nonetheless, the role of blood flow mechanics in the "near-wall" region is of utmost importance since this is where such couplings are most profound. In the near-wall region, blood flow serves to impart mechanical stresses on the vessel wall, as well as regulate the local transport of reactive material between the tissue and fluid domains. It is this latter mechanism that motivates the work presented herein.A compelling scenario involving the interaction between blood flow and the vessel wall is atherosclerosis, which is a leading cause of death worldwide. Atherosclerosis occurs mainly in locations of disturbed blood flow patterns [9,47]. The local transport of several substances near and at the vessel wall are known to influence atherosclerosis progression [56]. For example, previous studies have looked into transport of low density lipoproteins (LDL) [17,20,30,14], high density lipoproteins (HDL) [40,24], oxygen [16,27], nitric oxide (NO) [45,35], monocytes [12,14], and adenine triphosphate ATP and adenine diphosphate ADP [13,15,8] as important mass transport processes involved in atherosclerosis.Intravascular thrombosis is another compelling pathology associated with most cardiovascular diseases where near-wall transport becomes important [7,25]. The trajectories of individual platelets and the accumulation and residence time of chemical solutes including ADP, thrombin, and various blood factors control clot formation. These solutes, and especially in activated form, are generated at the vessel wall or from bound platelets. Complex hemodynamics and flow stagnation are often associated with prothrombotic conditions. For example, intraluminal thrombus in abdominal aortic aneurysm (AAA) [57,54] complicates disease progression, and is thought to be strongly coupled to flow stagnation and recirculation. The chaotic flow field in AAAs [3] Near-wall transport can either be (i) explicitly modeled for a specific transport problem, or (ii) inferred from appropriate hemodynamics meas...

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Biochemomechanics of Intraluminal Thrombus in Abdominal Aortic Aneurysms

Cited by 88 publications

References 132 publications

Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging

Assessing the Stability of Aortic Aneurysms with Pulse Wave Imaging

A haemodynamic predictor of intraluminal thrombus formation in abdominal aortic aneurysms

Wall shear stress exposure time: a Lagrangian measure of near-wall stagnation and concentration in cardiovascular flows

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