WITHDRAWN: The Impact of Using Inner-to-Inner Wall Diameter                     Measurement of Abdominal Aortic Aneurysm

A new experimental setup has been implemented to precisely measure the deformations of an entire model abdominal aortic aneurysm (AAA). This setup addresses a gap between the computational and experimental models of AAA that have aimed at improving the limited understanding of aneurysm development and rupture. The experimental validation of the deformations from computational approaches has been limited by a lack of consideration of the large and varied deformations that AAAs undergo in response to physiologic flow and pressure. To address the issue of experimentally validating these calculated deformations, a stereoscopic imaging system utilizing two cameras was constructed to measure model aneurysm displacement in response to pressurization. The three model shapes, consisting of a healthy aorta, an AAA with bifurcation, and an AAA without bifurcation, were also evaluated with computational solid mechanical modeling using finite elements to assess the impact of differences between material properties and for comparison against the experimental inflations. The device demonstrated adequate accuracy (surface points were located to within 0.07 mm) for capturing local variation while allowing the full length of the aneurysm sac to be observed at once. The experimental model AAA demonstrated realistic aneurysm behavior by having cyclic strains consistent with reported clinical observations between pressures 80 and 120 mm Hg. These strains are 1–2%, and the local spatial variations in experimental strain were less than predicted by the computational models. The three different models demonstrated that the asymmetric bifurcation creates displacement differences but not cyclic strain differences within the aneurysm sac. The technique and device captured regional variations of strain that are unobservable with diameter measures alone. It also allowed the calculation of local strain and removed rigid body motion effects on the strain calculation. The results of the computations show that an asymmetric aortic bifurcation created displacement differences but not cyclic strain differences within the aneurysm sac.

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Maximum Diameter of Native Abdominal Aortic Aneurysm Measured by Angio-Computed Tomography

Aorta ◽

10.12945/j.aorta.2015.14-059 ◽

2015 ◽

Vol 03 (02) ◽

pp. 47-55 ◽

Cited By ~ 6

Author(s):

Caroline Mora ◽

Claude Marcus ◽

Coralie Barbe ◽

Fiona Ecarnot ◽

Anne Long

Keyword(s):

Computed Tomography ◽

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Weighted Kappa ◽

Maximum Diameter ◽

Clinical Decisions ◽

Diameter Measurement ◽

Double Blind ◽

Automated Method ◽

Abdominal Aortic

Background: Computed tomography angiography (CTA) is the reference technique for the measurement of native maximum abdominal aortic aneurysm (AAA) diameter when surgery is being considered. However, there is a wide choice available for the methodology of maximum AAA diameter measurement on CTA, and to date, no consensus has been reached on which method is best. We analyzed clinical decisions based on these various measures of native maximum AAA diameter with CTA, then analyzed their reproducibility and identified the method of measurement yielding the highest agreement in terms of patient management. Materials and Methods: Three sets of measures in 46 native AAA were obtained, double-blind by three radiologists (J, S, V) on orthogonal planes, curved multiplanar reconstructions, and semi-automated-software, based on the AAA-lumen centerline. From each set, the clinical decision was recorded as follows: "Follow-up" (if all diameters <50 mm), "ambiguous" (if at least one diameter <50 mm AND at least one ≥50 mm) or "Surgery " (if all diameters ≥50 mm). Intra- and interobserver agreements in clinical decisions were compared using the weighted Kappa coefficient. Results: Clinical decisions varied according to the measurement sets used by each observer, and according to intra and interobserver (lecture#1) reproducibility. Based on the first reading of each observer, the number of AAA proposed for surgery ranged from 11 to 24 for J, 5 to 20 for S, and 15 to 23 for V. The rate of AAAs classified as "ambiguous" varied from 11% (5/46) to 37% (17/46).The semi-automated method yielded very good intraand interobserver agreements in clinical decisions in all comparisons (Kappa range 0.83–1.00). Conclusion: The semi-automated method seems to be appropriate for native AAA maximum diameter measurement on CTA. In the absence of AAA outer-wallbased software more robust for complex AAA, clinical decisions might best be made with diameter values obtained using this technique.

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The Impact of Vascular Quality Initiative Surgeon Volume on Mortality After Open Abdominal Aortic Aneurysm Repair in the Modern Era

Journal of Vascular Surgery ◽

10.1016/j.jvs.2019.06.073 ◽

2019 ◽

Vol 70 (3) ◽

pp. e47-e48

Author(s):

Gaurav Sharma ◽

Arin Madenci ◽

Kerollos Wanis ◽

Christine Lotto ◽

Samir Shah ◽

...

Keyword(s):

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Abdominal Aortic Aneurysm Repair ◽

Surgeon Volume ◽

Abdominal Aortic ◽

Aneurysm Repair ◽

The Impact ◽

Aortic Aneurysm Repair ◽

Modern Era

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The Impact of an Abdominal Aortic Aneurysm on Aortic Wave Reflection

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-175514 ◽

2007 ◽

Author(s):

Abigail Swillens ◽

Lieve Lanoye ◽

Julie De Backer ◽

Nikos Stergiopulos ◽

Frank Vermassen ◽

...

Keyword(s):

Abdominal Aortic Aneurysm ◽

Aortic Aneurysm ◽

Wave Reflection ◽

Numerical Models ◽

Aortic Aneurysms ◽

Western World ◽

Parameter Study ◽

Linear Wave ◽

Abdominal Aortic ◽

The Impact

The economical growth and increased welfare in the Western world have a reverse side, with an increased death toll due to cardiovascular diseases. Among these, aortic aneurysms (a local dilation) are particularly lethal as they may grow unnoticed until rupture occurs. In this study, we assessed the impact of the presence of an abdominal aortic aneurysm on arterial hemodynamics and wave reflection in particular. Experimental and numerical methods were applied. Linear wave separation was used to quantify the reflections; wave intensity analysis was applied to assess the nature of the reflected waves. In both the experimental and numerical models, negative reflections were found in the upper aorta corresponding to a backward expansion wave caused by the sudden expansion of the aorta. A numerical parameter study demonstrated that larger diameters and more compliant aneurysms generate stronger negative reflections.

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