Assessment of Abdominal Aortic Aneurysm Wall Distensibility With Electrocardiography-Gated Computed Tomography

Moláček, Jiří; Baxa, Jan; Houdek, Karel; Třeška, Vladislav; Ferda, Jiří

doi:10.1016/j.avsg.2011.05.034

Cited by 17 publications

(15 citation statements)

References 11 publications

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“…Specifically, we found that in most of the small AAAs, the wall appears to be stiffer than the upper aortic segment, which agrees with previous studies [13,23,30]. However, some large AAAs in our study appeared to be more distensible compared to the upper aortic segment.…”

Section: Discussionsupporting

confidence: 93%

“…However, some large AAAs in our study appeared to be more distensible compared to the upper aortic segment. Molacek et al [23], who although did not account for the effect of ILT on wall loading in their analysis, also found AAA distensibility values that either reached or even exceeded the values of the upper healthy aorta. Wilson's et al observed that AAAs that did not become stiffer, or became more distensible during their evolution were at a particularly high risk of rupture [40].…”

Section: Discussionmentioning

confidence: 91%

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The influence of intraluminal thrombus on noninvasive abdominal aortic aneurysm wall distensibility measurement

Metaxa

Kontopodis

Vavourakis

et al. 2014

Med Biol Eng Comput

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Abdominal aortic aneurysm wall distensibility can be estimated by measuring pulse pressure and the corresponding sac volume change, which can be obtained by measuring wall displacement. This approach, however, may introduce error if the role of thrombus in assisting the wall in bearing the pulse pressure loading is neglected. Our aim was to introduce a methodology for evaluating and potentially correcting this error in estimating distensibility. Electrocardiogram-gated computed tomography images of eleven patients were obtained, and the volume change between diastole and systole was measured. Using finite element procedures, we determined the equivalent pulse pressure loading that should be applied to the wall of a model where thrombus was digitally removed, to yield the same sac volumetric increase caused by applying the luminal pulse pressure to the model with thrombus. The equivalent instead of the measured pulse pressure was used in the distensibility expression. For a relative volumetric thrombus deposition (V ILT) of 50 %, a 62 % distensibility underestimation resulted when thrombus role was neglected. A strong linear correlation was observed between distensibility underestimation and V ILT. To assess the potential value of noninvasive wall distensibility measurement in rupture risk stratification, the role of thrombus on wall loading should be further investigated.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 91%

The influence of intraluminal thrombus on noninvasive abdominal aortic aneurysm wall distensibility measurement

Metaxa

Kontopodis

Vavourakis

et al. 2014

Med Biol Eng Comput

View full text Add to dashboard Cite

show abstract

“…Typically, the change in diameter of a normal aorta near the renal-aortic bifurcation throughout the cardiac cycle is about 2 mm [40]. Although AAA tissue has been reported to have less distensibility than a normal aorta due to a loss of tissue elasticity, an increase in collagen deposition, and a possible mechanical cushioning effect from the thrombus [41] [42], AAA deformations may be significant. The linear model, however, may be used together with gated imaging modalities, e.g., electrocardiography gated CT scans or MRI scans, which allow image reconstruction at specific phases of the cardiac cycle.…”

Section: Discussionmentioning

confidence: 99%

Improving the Efficiency of Abdominal Aortic Aneurysm Wall Stress Computations

et al. 2014

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An abdominal aortic aneurysm is a pathological dilation of the abdominal aorta, which carries a high mortality rate if ruptured. The most commonly used surrogate marker of rupture risk is the maximal transverse diameter of the aneurysm. More recent studies suggest that wall stress from models of patient-specific aneurysm geometries extracted, for instance, from computed tomography images may be a more accurate predictor of rupture risk and an important factor in AAA size progression. However, quantification of wall stress is typically computationally intensive and time-consuming, mainly due to the nonlinear mechanical behavior of the abdominal aortic aneurysm walls. These difficulties have limited the potential of computational models in clinical practice. To facilitate computation of wall stresses, we propose to use a linear approach that ensures equilibrium of wall stresses in the aneurysms. This proposed linear model approach is easy to implement and eliminates the burden of nonlinear computations. To assess the accuracy of our proposed approach to compute wall stresses, results from idealized and patient-specific model simulations were compared to those obtained using conventional approaches and to those of a hypothetical, reference abdominal aortic aneurysm model. For the reference model, wall mechanical properties and the initial unloaded and unstressed configuration were assumed to be known, and the resulting wall stresses were used as reference for comparison. Our proposed linear approach accurately approximates wall stresses for varying model geometries and wall material properties. Our findings suggest that the proposed linear approach could be used as an effective, efficient, easy-to-use clinical tool to estimate patient-specific wall stresses.

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“…It is obvious that the aneurysm size is not the only factor determining the risk of rupture. Other factors have also been discussed, such as the presence of infection, progression of the inflammatory reaction in the wall, distensibility [15], etc. Precise knowledge of the structure of the wall can be helpful in identifying such factors.…”

Section: Discussionmentioning

confidence: 99%

Proteomic analysis of the abdominal aortic aneurysm wall

Moláček

Mareš²,

Třeška

et al. 2013

Surg Today

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PurposesA ruptured AAA (rAAA) is a common cause of death in males over 60 years of age, and the global mortality from rAAA exceeds 80 %. The pathological processes occurring in the wall of the developing AAA are still unclear. The potential pathophysiological mechanisms underlying aortic aneurysms have been examined by many studies using immunohistochemistry and were, therefore, targeted at specific, preselected protein antigens.MethodsWe collected samples of tissue from anterior wall of an aneurysm sac from 15 patients indicated for AAA resection (group A) during the period from 2010 to 2011. These samples were subjected to a proteomic analysis. In addition, we collected control samples of identical aortic tissue from 10 heart-beating deceased organ donors (group B).ResultsA total of 417 differentially expressed protein fractions were identified, 18 of which were only detected in the healthy controls, while 85 were specific for aneurysm tissue and 314 were detectable in both groups. In 175 protein fractions, the gel-derived spot volumes differed significantly between aneurismal and healthy aortic tissue.ConclusionsWe found a significant difference in the proteome of the AAA tissue and non-dilated aortic tissue. We demonstrated that the AAA proteome is considerably richer and more varied than the healthy and atherosclerotic aorta. We believe that our results clearly demonstrate a completely different etiopathogenesis of atherosclerosis and aneurismal disease.

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Assessment of Abdominal Aortic Aneurysm Wall Distensibility With Electrocardiography-Gated Computed Tomography

Cited by 17 publications

References 11 publications

The influence of intraluminal thrombus on noninvasive abdominal aortic aneurysm wall distensibility measurement

The influence of intraluminal thrombus on noninvasive abdominal aortic aneurysm wall distensibility measurement

Improving the Efficiency of Abdominal Aortic Aneurysm Wall Stress Computations

Proteomic analysis of the abdominal aortic aneurysm wall

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