| 1. |
- Gasser, T. Christian, et al.
(författare)
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A novel strategy to translate the biomechanical rupture risk of abdominal aortic aneurysms to their equivalent diameter risk : Method and retrospective validation
- 2014
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 47:3, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To translate the individual abdominal aortic aneurysm (AAA) patient's biomechanical rupture risk profile to risk-equivalent diameters, and to retrospectively test their predictability in ruptured and non-ruptured aneurysms. Methods: Biomechanical parameters of ruptured and non-ruptured AAAs were retrospectively evaluated in a multicenter study. General patient data and high resolution computer tomography angiography (CTA) images from 203 non-ruptured and 40 ruptured aneurysmal infrarenal aortas. Three-dimensional AAA geometries were semi-automatically derived from CTA images. Finite element (FE) models were used to predict peak wall stress (PWS) and peak wall rupture index (PWRI) according to the individual anatomy, gender, blood pressure, intraluminal thrombus (ILT) morphology, and relative aneurysm expansion. Average PWS diameter and PWRI diameter responses were evaluated, which allowed for the PWS equivalent and PWRI equivalent diameters for any individual aneurysm to be defined. Results: PWS increased linearly and PWRI exponentially with respect to maximum AAA diameter. A size-adjusted analysis showed that PWS equivalent and PWRI equivalent diameters were increased by 7.5 mm (p = .013) and 14.0 mm (p < .001) in ruptured cases when compared to non-ruptured controls, respectively. In non-ruptured cases the PWRI equivalent diameters were increased by 13.2 mm (p < .001) in females when compared with males. Conclusions: Biomechanical parameters like PWS and PWRI allow for a highly individualized analysis by integrating factors that influence the risk of AAA rupture like geometry (degree of asymmetry, ILT morphology, etc.) and patient characteristics (gender, family history, blood pressure, etc.). PWRI and the reported annual risk of rupture increase similarly with the diameter. PWRI equivalent diameter expresses the PWRI through the diameter of the average AAA that has the same PWRI, i.e. is at the same biomechanical risk of rupture. Consequently, PWRI equivalent diameter facilitates a straightforward interpretation of biomechanical analysis and connects to diameter-based guidelines for AAA repair indication. PWRI equivalent diameter reflects an additional diagnostic parameter that may provide more accurate clinical data for AAA repair indication.
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| 2. |
- Nchimi, A., et al.
(författare)
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Emerging tools to assess the risk of rupture in AAA : Wall stress and FDG PET
- 2019
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Ingår i: Surgical Management of Aortic Pathology: Current Fundamentals for the Clinical Management of Aortic Disease. - Vienna : Springer International Publishing. - 9783709148747 - 9783709148723 ; , s. 465-485
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Abdominal aortic aneurysm (AAA) rupture is a significant cause of mortality in developed countries. The growth rate and the rupture of AAA may be unpredictable. This chapter places a special emphasis on evaluating patient-specific approaches to the risk of rupture of AAA, using imaging. Specifically, we describe two pathways of assessing this risk: one being the use of morphologic imaging data to compute wall stress (and wall stress-related parameters) via finite element simulation (FES) and the other, the use of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) to assess biological processes in the aortic wall components. Both methods are described, along with the limits preventing their widespread use. Nevertheless, the current diameter-based clinical scenarios could be yet impacted by the reported value of FES and FDG PET to predict the risk of AAA rupture. Lastly, the relationship between wall stress and the biological activities as described by FDG PET points at least partially to genetic or acquired alterations of the arterial wall response to wall stress, which can be found in familial aneurysms or in smokers, for example. An integrated patient-specific risk assessment strategy that would include imaging parameters along with personal and heritable risk factors is becoming increasingly suitable.
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