Aneurysmen und Dissektionen der thorakalen und abdominellen Aorta

Heider, P.; Wolf, Oliver T.; Reeps, Christian; Hanke, Martin; Zimmermann, Alexander; Berger, Hermann; Eckstein, H.‐H.

doi:10.1007/s00104-007-1370-0

Cited by 8 publications

(9 citation statements)

References 43 publications

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“…30-day-mortality of elective AAA repair ranges between 0.6 and 5.8% for open repair and at 1.7% for endovascular aortic repair. 12,13 Considering that only 25% of all AAAs rupture during patients' lifetime 3,42 it becomes obvious that surgeons have to balance rupture risk with the risk of elective repair. In order to assess the relative AAA rupture risk, the simple but well-evaluated maximum diameter criterion is most commonly used in clinical practice.…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Diameter, Wall Stress, and Rupture Potential Index for Abdominal Aortic Aneurysm Rupture Risk Prediction

et al. 2010

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An abdominal aortic aneurysm (AAA) is a balloon-like dilation of the aorta, which is potentially fatal in case of rupture. Computational finite element (FE) analysis is a promising approach to a more accurate and patient-specific rupture risk prediction. AAA wall strength and rupture potential index (RPI) calculation are implemented in our FE software. Static structural FE simulations are performed on n = 30 non-ruptured asymptomatic, n = 9 non-ruptured symptomatic, and n = 14 ruptured AAAs. We calculate maximum values for diameter, wall displacement, strain, stress, and RPI as well as minimum wall strength for every AAA. All investigated quantities, except minimum strength, show statistically significant differences between non-ruptured asymptomatic and symptomatic/ruptured AAAs. Maximum wall stress and especially the RPI are notably increased for symptomatic and ruptured AAAs. The biggest difference is found to be the RPI (Δ = 44.9%, p = 8.0e-5). Lowest RPI obtained for symptomatic or ruptured AAAs is 0.3. The RPI of more than 55% of the investigated asymptomatic AAAs falls below this value. Maximum wall stress and maximum RPI criteria enable a reliable rupture risk evaluation for AAAs. Especially in the diameter range where surgical indication is not obvious, the RPI holds great potential for improvement of clinical decisions.

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Section: Introductionmentioning

confidence: 99%

A Comparison of Diameter, Wall Stress, and Rupture Potential Index for Abdominal Aortic Aneurysm Rupture Risk Prediction

et al. 2010

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“…In case of rupture, nine out of ten patients die before reaching the hospital and mortality rates of patients with ruptured AAA treated operatively vary from 35 to 70% (Ockert et al 2007). Prophylactic surgery also is not without potential risk as perioperative mortality rates in conventional open surgery lie between 0.6 and 5.8% (Heider et al 2007). Considering that only 25% of all AAAs rupture while a patient's lifetime (Vorp 2007), it is obvious that surgeons have to oppose rupture risk to risk of surgery.…”

Section: Introductionmentioning

confidence: 97%

Impact of calcifications on patient-specific wall stress analysis of abdominal aortic aneurysms

Maier

Gee

Reeps

et al. 2010

Biomech Model Mechanobiol

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As a degenerative and inflammatory desease of elderly patients, about 80% of abdominal aortic aneurysms (AAA) show considerable wall calcification. Effect of calcifications on computational wall stress analyses of AAAs has been rarely treated in literature so far. Calcifications are heterogeneously distributed, non-fibrous, stiff plaques which are most commonly found near the luminal surface in between the intima and the media layer of the vessel wall. In this study, we therefore investigate the influence of calcifications as separate AAA constituents on finite element simulation results. Thus, three AAAs are reconstructed with regard to intraluminal thrombus (ILT), calcifications and vessel wall. Each patient-specific AAA is simulated twice, once including all three AAA constituents and once neglecting calcifications as it is still common in literature. Parameters for constitutive modeling of calcifications are thereby taken from experiments performed by the authors, showing that calcifications exhibit an almost linear stress-strain behavior with a Young's modulus E ≥ 40 MPa. Simulation results show that calcifications exhibit significant load-bearing effects and reduce stress in adjacent vessel wall. Average stress within the vessel wall is reduced by 9.7 to 59.2%. For two out of three AAAs, peak wall stress decreases when taking calcifications into consideration (8.9 and 28.9%). For one AAA, simulated peak wall stress increases by 5.5% due to stress peaks near calcification borders. However, such stress singularities due to sudden stiffness jumps are physiologically doubtful. It can further be observed that large calcifications are mostly situated in concavely shaped regions of the AAA wall. We deduce that AAA shape is influenced by existent calcifications, thus crucial errors occur if they are neglected in computational wall stress analyses. A general increase in rupture risk for calcified AAAs is doubted.

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“…1 Therefore, it often goes undetected until a rupture unexpectedly occurs, resulting in a mortality rate of >90%. 2, 3, 4 Thus far and despite all advances in the management of AAA, the only established predictor for the relative, but not individual, risk stratification of asymptomatic AAA is the maximum diameter. 5, 6, 7 Therefore, a better understanding of the pathophysiological processes leading from AAA wall destabilization to rupture may lead to the discovery of new, patient-specific and more accurate predictors of AAA rupture risk.…”

Section: Introductionmentioning

confidence: 99%

Quantitative expression and localization of cysteine and aspartic proteases in human abdominal aortic aneurysms

et al. 2014

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Cysteine and aspartic proteases possess high elastolytic activity and might contribute to the degradation of the abdominal aortic aneurysm (AAA) wall. The aim of this study was to analyze, in detail, the proteases (cathepsins B, D, K, L and S, and inhibitor cystatin C) found in human AAA and healthy aortic tissue samples. The vessel walls from AAA patients (n=36) and nonaneurysmal aortae (n=10) were retrieved using conventional surgical repair and autopsy methods. Serum samples from the same AAA patients and 10 healthy volunteers were also collected. Quantitative expression analyses were performed at the mRNA level using real-time reverse transcriptase-PCR (RT–PCR). Furthermore, analyses at the protein level included western blot and immunoprecipitation analyses. Cellular sources of cysteine/aspartic proteases and cystatin C were identified by immunohistochemistry (IHC). All cysteine/aspartic proteases and cystatin C were detected in the AAA and control samples. Using quantitative RT–PCR, a significant increase in expression was observed for cathepsins B (P=0.021) and L (P=0.018), compared with the controls. Cathepsin B and cystatin C were also detected in the serum of AAA patients. Using IHC, smooth muscle cells (SMCs) and macrophages were positive for all of the tested cathepsins, as well as cystatin C; in addition, the lymphocytes were mainly positive for cathepsin B, followed by cathepsins D and S. All cysteine/aspartic proteases analyzed in our study were detected in the AAA and healthy aorta. The highest expression was found in macrophages and SMCs. Consequently, cysteine/aspartic proteases might play a substantial role in AAA.

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Aneurysmen und Dissektionen der thorakalen und abdominellen Aorta

Cited by 8 publications

References 43 publications

A Comparison of Diameter, Wall Stress, and Rupture Potential Index for Abdominal Aortic Aneurysm Rupture Risk Prediction

A Comparison of Diameter, Wall Stress, and Rupture Potential Index for Abdominal Aortic Aneurysm Rupture Risk Prediction

Impact of calcifications on patient-specific wall stress analysis of abdominal aortic aneurysms

Quantitative expression and localization of cysteine and aspartic proteases in human abdominal aortic aneurysms

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