Дисертації з теми "Abdomina Aortic Aneurysm"
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1
Rossaak, Jeremy Ian, and n/a. "The genetics of abdominal aortic aneurysms." University of Otago. Dunedin School of Medicine, 2004. http://adt.otago.ac.nz./public/adt-NZDU20070502.143818.
Повний текст джерелаАнотація:
Abdominal Aortic Aneurysms (AAA) are amongst the top ten most common cause of death in those over 55 years of age. The disease is usually asymptomatic, often being diagnosed incidentally. Once diagnosed, elective repair of an AAA results in excellent long-term survival with a 3-5% operative mortality. However, up to one half of patients present with ruptured aneurysms, a complication that carries an 80% mortality in the community, and of those reaching hospital, a 50% mortality. Clearly early diagnosis and treatment results in improved survival.
Screening for AAA, with ultrasound, would detect aneurysms early, prior to rupture. However, debate continues over the cost effectiveness of population based screening programmes. The identification of a sub-population at a higher risk of developing AAA would increase the yield of a screening prograrmne. A number of populations have been examined, none of which have received international acceptance.
About 20% of patients with an AAA have a family history of an aneurysm. The disease is also considered to be a disease of Caucasians, both facts suggesting a strong genetic component to the disease. Perhaps a genetically identified sub-population at a high risk of developing an AAA would prove to be an ideal population for screening.
This thesis examines the incidence of aneurysms and the family histories of patients with AAA in the Otago region of New Zealand. Almost twenty percent of the population has a family history of AAA. DNA was collected from each of these patients for genetic analysis. The population was divided into familial AAA and non-familial AAA for the purpose of genetic analysis and compared to a control population.
AAA is believed to be a disease of Caucasians; a non-Caucasian population with a low incidence of AAA may prove to be a good control population for genetic studies. A literature review demonstrated a higher incidence of AAA in Caucasians than other ethnic groups and within Caucasians a higher incidence in patients of Northern European origin. The incidence was low in Asian communities, even in studies involving of migrant Asian populations. The New Zealand Maori are believed to have originated from South East Asia, therefore could be expected to have a low incidence of AAA and would make an ideal control population for genetic studies. A pilot study was undertaken to examine the incidence of AAA in the New Zealand Maori. The age standardised incidence of AAA proved to be at least equal in Maori to non-Maori, with a more aggressive form of the disease in Maori, manifesting with a younger age at presentation and a higher incidence of ruptured aneurysms at diagnosis.
It is well known that at the time of surgery, an AAA is at the end stage in its life. At this time, inflammation and matrix metalloproteinases (MMP) enzymes are prevalent within the aneurysm wall and have destroyed the wall of the aorta. One of the most important genetic pathways regulating these enzymes is the plasminogen activator inhibiter 1-Tissue plasminogen activator-plasmin pathway.
Genetic analysis of this pathway demonstrated an association of the 4G5G polymorphism in the promoter of the PAl-1 gene with familial AAA. In this insertion:deletion polymorphism, the 5G variant binds an activator and repressor, resulting in reduced PAI-1 expression and ultimately increased MMP activation. This allele was associated with familial aneurysms, 47% versus 62% non-familial AAA and 61% controls (p=0.024).
A polymorphism within the tissue plasminogen activator gene was also examined and no association was found with AAA.
Another way the MMPs expression could be increased is from mutations or polymorphisms in their own genetic structure. Stromelysin 3 is itself a MMP capable of destroying the aortic wall and it has a role in activating other MMPs. A 5A6A insertion:deletion polymorphism exists in the promoter of this gene. The 5A allele variant results in increased stromelysin expression and is associated with AAA 46% versus 33% in controls p=0. 0006.
The actions of the MMPs are themselves inhibited by the tissue inhibitors of matrix metalloproteinases. The TIMP genes have been sequenced; two polymorphisms have been identified in the non-coding promoter area of the TIMP 1 gene. Further studies are necessary to examine the effect of these polymorphisms.
Inflammation has been implicated in aneurysm progression. One of the roles of the inflammatory cells found in an aneurysm is to deliver the MMP�s to the AAA. The HLA system is integral in controlling this inflammation and was therefore examined.
From this series of studies it is concluded that there is a genetic component to AAA. This thesis presents the first genetic polymorphism associated with familial AAA and explores the role of a genetic pathway in the formation of AAA.
2
Mello, Flávia Moerbeck Casadei de [UNESP]. "Aneurisma da aorta abdominal infra-renal: avaliação ultra-sonográfica em homens acima de 50 anos." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/87358.
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mello_fmc_me_botfm.pdf: 590394 bytes, checksum: 6bd49179dbdb5496cc2a8f6a9ebad2ed (MD5)Com o objetivo de avaliar a ocorrência de aneurisma da aorta abdominal infra-renal (AAAIR), estudou-se uma amostra da população masculina do Município de Marília, com idade igual ou acima de 50 anos, no período de 2000 a 2002. Foram avaliados 240 homens por meio da ultrasonografia abdominal (USAb), com média de idade de 65,1 anos (±9,8 anos). A aorta abdominal foi medida no sentido ânteroposterior (AP) e látero-lateral (LL) aproximadamente a 2cm abaixo da artéria mesentérica superior (AMS) e 2cm acima de sua bifurcação. O critério utilizado para considerar aneurisma foi o maior diâmetro encontrado igual ou maior que 3,1cm. Também por questionário, foram avaliados os fatores de risco (tabagismo, sedentarismo, alimentação) e as doenças associadas (HAS, DPOC, IM, DM, AOP ou hiperlipidemia). Nos 240 homens, foram encontrados 11 aneurismas, sendo, portanto, a freqüência de 4,6%. Desses 11 aneurismas, 8 mediam entre 3,1 e 4cm (72,7%) e 3, entre 4,1 e 5cm (27,3%). O maior diâmetro da aorta aneurismática foi de 5 cm (sentido AP a 2cm abaixo da AMS). Foi encontrada uma associação significativa entre aneurisma e AOP e DM, não ocorrendo o mesmo com os demais fatores de risco ou outras doenças associadas. A freqüência de aneurisma encontrada em nossa amostra não foi diferente da referida nos estudos populacionais publicados na literatura, o que mostra a importância da doença em nosso meio, e os indivíduos com AOP e DM têm risco maior de desenvolver a doença.
In order to evaluate the occurrence of Infra-Renal Abdominal Aortic Aneurysm (AAAIR), a sample of the male population in the city of Marília aged 50 years or older was studied from 2000 to 2002. A group of 240 men with mean age of 65,1 years (±9,8 years) was evaluated through abdominal ultra-sonography examination. The abdominal aorta was measured in the anteroposterior (AP) and in the latero-lateral directions (LL) approximately 2cm below the superior mesenteric artery and 2cm above its bifurcation. The largest diameter equal or larger than 3.1cm found was the criterion used for aneurysm. Risk factors such as smoking, eating, and exercise habits and associated diseases (systemic arterial hypertension, chronic obstructive pulmonary disease, myocardial infarction, diabetes mellitus, occlusive peripheral arterial disease, or hyperlipidemia) were also evaluated through questionnaires. Eleven aneurysms were found in the 240 men, which meant a frequency of 4,6%. Out of these 11 aneurysms, 8 measured from 3.1 to 4cm (72,7%) and 3 measured from 4.1 to 5cm (27,3%). The largest diameter of the aneurysmatic aorta was 5cm (AP direction approximately 2cm of the superior mesenteric artery). A significant association between aneurysm and peripheral vascular disease and diabetes mellitus was found. The same did not occur with the other risk factors or other associated diseases. The frequency of aneurysm found in our sample was not different from the frequency mentioned in population studies published in the literature, which shows the importance of the disease in our environment and that patients with peripheral vascular disease and diabetes mellitus have a higher risk to develop the disease.
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Mello, Flávia Moerbeck Casadei de. "Aneurisma da aorta abdominal infra-renal : avaliação ultra-sonográfica em homens acima de 50 anos /." Botucatu : [s.n.], 2003. http://hdl.handle.net/11449/87358.
Повний текст джерелаАнотація:
Orientador: Hamilton Almeida RolloResumo: Com o objetivo de avaliar a ocorrência de aneurisma da aorta abdominal infra-renal (AAAIR), estudou-se uma amostra da população masculina do Município de Marília, com idade igual ou acima de 50 anos, no período de 2000 a 2002. Foram avaliados 240 homens por meio da ultrasonografia abdominal (USAb), com média de idade de 65,1 anos (±9,8 anos). A aorta abdominal foi medida no sentido ânteroposterior (AP) e látero-lateral (LL) aproximadamente a 2cm abaixo da artéria mesentérica superior (AMS) e 2cm acima de sua bifurcação. O critério utilizado para considerar aneurisma foi o maior diâmetro encontrado igual ou maior que 3,1cm. Também por questionário, foram avaliados os fatores de risco (tabagismo, sedentarismo, alimentação) e as doenças associadas (HAS, DPOC, IM, DM, AOP ou hiperlipidemia). Nos 240 homens, foram encontrados 11 aneurismas, sendo, portanto, a freqüência de 4,6%. Desses 11 aneurismas, 8 mediam entre 3,1 e 4cm (72,7%) e 3, entre 4,1 e 5cm (27,3%). O maior diâmetro da aorta aneurismática foi de 5 cm (sentido AP a 2cm abaixo da AMS). Foi encontrada uma associação significativa entre aneurisma e AOP e DM, não ocorrendo o mesmo com os demais fatores de risco ou outras doenças associadas. A freqüência de aneurisma encontrada em nossa amostra não foi diferente da referida nos estudos populacionais publicados na literatura, o que mostra a importância da doença em nosso meio, e os indivíduos com AOP e DM têm risco maior de desenvolver a doença.
Abstract: In order to evaluate the occurrence of Infra-Renal Abdominal Aortic Aneurysm (AAAIR), a sample of the male population in the city of Marília aged 50 years or older was studied from 2000 to 2002. A group of 240 men with mean age of 65,1 years (±9,8 years) was evaluated through abdominal ultra-sonography examination. The abdominal aorta was measured in the anteroposterior (AP) and in the latero-lateral directions (LL) approximately 2cm below the superior mesenteric artery and 2cm above its bifurcation. The largest diameter equal or larger than 3.1cm found was the criterion used for aneurysm. Risk factors such as smoking, eating, and exercise habits and associated diseases (systemic arterial hypertension, chronic obstructive pulmonary disease, myocardial infarction, diabetes mellitus, occlusive peripheral arterial disease, or hyperlipidemia) were also evaluated through questionnaires. Eleven aneurysms were found in the 240 men, which meant a frequency of 4,6%. Out of these 11 aneurysms, 8 measured from 3.1 to 4cm (72,7%) and 3 measured from 4.1 to 5cm (27,3%). The largest diameter of the aneurysmatic aorta was 5cm (AP direction approximately 2cm of the superior mesenteric artery). A significant association between aneurysm and peripheral vascular disease and diabetes mellitus was found. The same did not occur with the other risk factors or other associated diseases. The frequency of aneurysm found in our sample was not different from the frequency mentioned in population studies published in the literature, which shows the importance of the disease in our environment and that patients with peripheral vascular disease and diabetes mellitus have a higher risk to develop the disease.
Mestre
4
Malina, Martin. "Endovascular repair of abdominal aortic aneurysms aspects on a novel technique /." Lund : Dept. of Vascular and Renal Diseases, Lund University, Malmö University Hospital, 1998. http://books.google.com/books?id=hWBsAAAAMAAJ.
Повний текст джерела
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Tenório, Emanuel Júnio Ramos. "Expressão dos níveis plasmáticos dos miRNA-191 e miRNA-455-3P em pacientes com aneurisma de aorta abdominal e suas relações com a evolução clínica após tratamento endovascular." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/17/17137/tde-10042018-142246/.
Повний текст джерелаАнотація:
Introdução: O aneurisma de aorta abdominal (AAA) é uma importante causa de morbimortalidade na população idosa. O tratamento endovascular está associado a menor morbimortalidade que o tratamento convencional, no entanto, necessita de um seguimento rigoroso com exames de imagem contrastados para confirmação da exclusão do saco aneurismático. Considerando que a formação de um aneurisma é um processo multifatorial complexo, envolvendo a remodelação destrutiva do tecido conjuntivo em todo o segmento afetado da parede da aorta e que este processo envolve uma inflamação crônica local, uma diminuição no número de células do músculo liso da túnica média, e fragmentação da matriz extracelular da aorta e ainda que um perfil de expressão aberrante de miRNAs tem sido associada a doenças humanas, incluindo disfunção cardiovascular propôs-se então a realização deste estudo envolvendo todo este processo. O objetivo principal foi quantificar e avaliar a resposta da expressão dos miRNAs à correção endovascular de aneurisma de aorta abdominal com base em dosagens séricas no seguimento de seis meses. População e Método: Foram recrutados 30 pacientes consecutivos com AAA sem outras doenças inflamatórias associadas, do Ambulatório de Cirurgia Vascular e Endovascular do HCFMRPUSP com indicação de tratamento endovascular. Foram escolhidos para estudo e dosagens séricas os miRNA-191 e miRNA-455-3p. A expressão diferencial dos miRNAs foi realizada pelo método de PCR em tempo real, após extração do RNA das amostras de sangue total em dois momentos, pré- operatório e após 6 meses de pós-operatório. Além disso, ferramentas de bioinformática foram utilizadas para determinar vias fisiopatológicas relacionadas ao AAA. Foram Colhidos dados de perfil demográfico, de seguimento clinico e exames de imagem com angiotomografia no pré-operatórios e após 6 meses. Resultados: Foi observado uma hiperexpressão dos miR-191 e miR-455-3p no sangue total dos pacientes com AAA. O tratamento endovascular dos pacientes com AAA resultou em diminuição significativa das expressões dos miRNAs estudados, indicando que a exclusão do saco aneurismático altera as expressões dos mesmos. Adicionalmente, as expressões dos miR-191 e miR-455-3p não apresentaram correlação com o diâmetro do aneurisma e a análise da influência dos diversos tipos de dispositivos utilizados para o tratamento endovascular dos AAA, não mostrou diferenças significativas nas expressões dos miR-191 e miR-455-3p. Conclusões: A hiperexpressão dos miR-191 e miR-455-3p com sua significativa redução apos o tratamento endovascular, pode sugerir a utilização dessas moléculas como potenciais biomarcadores no seguimento desses pacientes. Novos estudos com maior número de casos devem ser realizados com o objetivo de validar os dados obtidos incluindo pacientes com eventuais vazamentos.Background: Abdominal aortic aneurysm (AAA) is an important cause of morbidity and mortality in the elderly population. Endovascular treatment is associated with lower morbidity and mortality than conventional treatment, however, it requires a rigorous follow-up with contrast imaging tests to confirm the aneurysmal sac exclusion. Considering that the formation of an aneurysm is a complex multifactorial process, involving the destructive remodeling of the connective tissue throughout the affected segment of the aortic wall and that this process involves a chronic local inflammation, a decrease in the number of smooth muscle cells of the media tunic, and fragmentation of the extracellular matrix of the aorta and although an aberrant expression profile of miRNAs has been associated with human diseases, including cardiovascular dysfunction, it was proposed to carry out this study involving this whole process. The main objective was to quantify and evaluate miRNA expression response to endovascular correction of abdominal aortic aneurysm based on serum dosages at the six-month follow-up. Population and Method: We recruited 30 consecutive patients with AAA without other associated inflammatory diseases from the Ambulatory of Vascular and Endovascular Surgery of the HCFMRPUSP with indication of endovascular treatment. The miRNA-191 and miRNA-455-3p were selected for study and serum dosages. The differential expression of the miRNAs was performed by the real-time PCR method, after extraction of RNA from the whole blood samples at two moments, preoperatively and after 6 months of follow-up. In addition, bioinformatics tools were used to determine pathophysiological pathways related to AAA. Demographic profile, clinical follow-up and imaging examinations with angiotomography performed in the preoperative period and after 6 months were collected. Results: Hyperexpression of miR-191 and miR-455-3p in whole blood of AAA patients was observed. The endovascular treatment of patients with AAA resulted in a significant decrease in the expression of the miRNAS studied, indicating that the exclusion of the aneurysmal sac altered their expression. In addition, the expression of miR-191 and miR-455-3p showed no correlation with the diameter of the aneurysm and analysis of the influence of the various types of devices used for the endovascular treatment of AAA did not show significant differences in the expression of miR-191 And miR-455-3p. Conclusions: The hyperexpression of miR- 191 and miR-455-3p with its significant reduction after endovascular treatment may suggest the use of these molecules as potential biomarkers in the follow-up of these patients. New studies with a greater number of cases should be performed with the objective of validating the data obtained including patients with possible endoleaks.
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Svensjö, Sverker. "Screening for Abdominal Aortic Aneurysm." Doctoral thesis, Uppsala universitet, Kärlkirurgi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198677.
Повний текст джерелаАнотація:
Randomised controlled trials have demonstrated that mortality from Abdominal Aortic Aneurysm (AAA) can be cost-effectively reduced by ultrasound-screening of men. Evidence for screening women is insufficient. Reports of falling AAA incidence are emerging. In an effort to study screening for AAA in a contemporary setting, two cross-sectional multi-centre population-based studies of one-time screening of 65-year-old men, and 70-year-old women in Middle Sweden were undertaken. Cost-efficiency of one-time screening of 65-year-old men was evaluated in a decision-analysis model. Five-year outcomes in men invited to screening at age 65 and age 70, were studied in a longitudinal cohort study. A lower than expected (1.7%) prevalence of AAA in 65-year-old men was found, as well as a very low (0.4%) prevalence in 70-year-old women. Smoking was the dominating risk factor associated with AAA, but the association was stronger in women. The main cause of reduced contemporary prevalence was falling smoking rates in the population since 30 years. One-time screening of 65-year-old men was found to be cost-effective and deliver significant clinical impact. The cost per quality adjusted life-year gained, at 13-years follow-up, was €14706, which was below the recommended UK NICE threshold of €25000. 15 lives were saved by inviting 10000 to screening. Prevalence of AAA and the rate of incidental detection of AAAs in the population were important factors affecting cost-efficiency. New AAAs developed after 5 years in men screened normal at age 65, predominantly in men with sub-aneurysmal aortas (25-29mm) at 65, and smokers. The 5-year rate of AAA repair was high among men with screening detected AAAs, as was non-AAA related mortality. Ruptures were only documented among non-attenders. Conclusions: A lower than expected prevalence of AAA among 65-year-old men, an unchanged repair rate, and improved longevity of the elderly population was found. Although one-time screening for AAA was still cost-effective within a contemporary context, several issues need to be addressed; the threshold diameter for follow-up, the current rate of opportunistic detection of AAA in the population, re-screening of the entire population at a higher age, and targeted screening of smokers. Screening 70-year-old women who do not smoke is likely to be futile, thus ruling out population screening of women for AAA.
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Lowe, Christopher. "Three-dimensional ultrasound in the management of abdominal aortic aneurysm." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/threedimensional-ultrasound-in-themanagement-of-abdominal-aorticaneurysm(b8950db7-847b-4d11-a6a5-2a06b3bb66d0).html.
Повний текст джерелаАнотація:
Objectives: Clinical implementation of 3D ultrasound (3D-US) in vascular surgery is in its infancy. The aim of this thesis was to develop novel clinical applications for 3D-US in the diagnosis and management of abdominal aortic aneurysm (AAA). Methods: Four principle clinical applications were investigated. 1) Intraoperative imaging – The ability of 3D-US to detect and classify endoleaks was compared with digital subtraction angiography in patients undergoing EVAR. 2) Detection and classification of endoleaks following endovascular aneurysm repair (EVAR) – The abilityof 3D-US to accurately detect and classify endoleaks following EVAR was compared to CTA and the final multi-disciplinary team decision. 3) AAA volume measurement – measurements using magnetic and optically-tracked 3D-US were compared to CTA. 4) Biomechanical analysis – the challenges of using 3D-US to generate surface models for biomechanical simulation was explored by development of an interactive segmentation technique and comparison of paired CT and 3D-US datasets. Optimal results were used in finite element analysis (FEA) and computational fluid dynamic(CFD) simulations. Results: 3D-US out-performed uniplanar angiography for the detection of endoleaks during EVAR. This approach allowed contrast-free EVAR to be performed in patients with poor renal function. 3D contrast-enhanced ultrasound was superior to CTA for endoleak detection and classification when compared with the final decision of the multi-disciplinary team. Optimal results for AAA volume measurements were gained using an optically tracked 3D-US system in EVAR surveillance. However, there remained a significant mean difference of 13.6ml between CT and 3D-US. Complete technical success of generating geometries for use in biomechanical analysis using 3D-US was only 5%. When the optimal results were used, a comparable CFD analysis under the conditions of steady, laminar and Newtonian flow was achieved. Using basic modelling assumptions in FEA, peak von Mises and principle wall stress was found to be at the same anatomical location on both the CT and 3D-US models but the 3D-US model overestimated the wall stress values by 41% and 51% respectively. Conclusions: 3D-US could be clinically implemented for intra-operative imaging and EVAR surveillance in specific cases. 3D-US volume measurement is feasible but future work should aim to improve accuracy and inter-observer reliability. Although the results of biomechanical analysis using the optimal results was encouraging and provided a proof-of-principal, there are a number of technical developments required to make this approach feasible in a larger number of patients.
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Chinien, Ganessen. "Molecular genetics of abdominal aortic aneurysm." Thesis, King's College London (University of London), 2012. https://kclpure.kcl.ac.uk/portal/en/theses/molecular-genetics-of-abdominal-aortic-aneurysm(e269485a-e71a-41a7-9a8e-ae40eb968dd4).html.
Повний текст джерелаАнотація:
Abdominal aortic aneurysm (AAA) is a common disorder and a major cause of death. Pathological processes involved in AAA formation include inflammation, proteolysis, angiogenesis and apoptosis. It has also a strong familial predisposition with linkage studies identifying chromosomes 19q13 and 4q31 as susceptible loci. AAA is likely to be a polygenic disorder. Aims The aims of this study were to carry out a whole transcriptome analysis in order to identify novel genes and pathways that are differentially expressed between aneurysmal (AAA), atheromatous (AOD) and normal (NA) aortic tissue and to confirm a set of these differentially expressed genes using quantitative real time polymerase chain reaction (qRT-PCR). Methods RNA samples were prepared from full thickness aortic walls obtained during open repair of AAA, aortic bypass for AOD and transplant patients for NA. The quality of the RNA was assessed using the Bioanalyzer 2100 (Agilent) and Nanodrop. RNA was then reverse transcribed to cDNA which was then hybridised to the Human Genome (HG) -U133 plus 2.0 microarray (Affymetrix) that interrogates the whole human genome. The robustness of the genearray was assessed using data output quality control as defined by Affymetrix. Statistical analysis was then carried out using the GeneSpring software. Genes were considered to be significantly differentiated if they had at least a two-fold change and a P-value < 0.05 following Benjamini-Hochberg multiple correction testing. Genes were then classified according to their molecular functions. A set of consistently differentially expressed genes were confirmed using qRT-PCR with Taqman probes on a larger sample size compared with the microarray experiment. All pathway and network analysis on the differentially expressed genes were conducted using MetaCore software Version 6.3 (GeneGo, Inc). Results A total of 3320 genes and 233 genes were differentially expressed when comparing AAA with NA and AAA with AOD respectively.
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Djavani, Gidlund Khatereh. "Intra-abdominal Hypertension and Colonic Hypoperfusion after Abdominal Aortic Aneurysm Repair." Doctoral thesis, Uppsala universitet, Institutionen för kirurgiska vetenskaper, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-149241.
Повний текст джерелаАнотація:
Colonic ischaemia (CI), Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are devastating complications after abdominal aortic aneurysm (AAA) surgery. The aims of this thesis were to study the incidence and clinical consequences of IAH/ACS and the association between CI and intra-abdominal pressure (IAP) among patients undergoing OR for ruptured AAA (rAAA), to compare extraluminal pHi monitoring, with standard intra-luminal monitoring among patients operated on for AAA, and to study the frequency and clinical consequences of IAH/ACS after endovascular repair (EVAR) for rAAA. The incidence of ACS was 26% in a retrospective study of 27 patients undergoing OR for rAAA. Consensus definitions on IAH/ACS were appropriate for patients after OR for rAAA: 78% (7/9) of patients with IAH grade III or IV developed organ failure and all patients who developed CI had some degree of IAH. Active fluid resuscitation treating hypovolaemia to avoid CI may partly cause IAH. The association between CI and IAP was investigated in a prospective study on 29 patients operated on for rAAA, 86% (25/29) were treated for hypovolaemia and ten (34%) had both IAH and CI. Since monitoring colonic perfusion is very important and there is no ideal method, a new technique, extraluminal colonic tonometry to detect colonic perfusion was compared with standard intraluminal tonometry. Although, this new method was not able to determine the severity of ischaemia it may serve as a screening test. EVAR of rAAA is feasible and patients may benefit from this less invasive procedure. Of 29 patients treated with this technique, 10% developed ACS, and all patients except one with preoperative shock developed some degree of IAH. In conclusion, IAP/ACS is common after both OR and EVAR for rAAA, and is associated with adverse outcome. Monitoring IAP and colonic perfusion with timely intervention may improve outcome.
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Alves, Lais Missae Murakami Domingues Estraiotto. "Estudo da expressão sérica do microRNA-1281, proteína C reativa e avaliação da função renal em indivíduos com aneurisma de aorta abdominal antes e após tratamento endovascular." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/17/17137/tde-28052018-160605/.
Повний текст джерелаАнотація:
Introdução: O aneurisma de aorta abdominal (AAA) é uma doença prevalente e silenciosa também relacionada com a atividade inflamatória. Atualmente, a abordagem endovascular tem sido utilizada como principal técnica devido à inúmeras vantagens. Porém tem uma maior taxa de reintervenções e necessita de seguimento periódico com angiotomografias, o que aumenta custos e tem implicações como alteração da função renal além do acúmulo progressivo de radiação. Tais condições justificam a busca por possíveis biomarcadores que possam contribuir para um melhor seguimento. Objetivos: Neste estudo, buscou-se correlacionar o microRNA-1281, proteína C reativa (PCR) e a avaliação da função renal de indivíduos com AAA com a evolução dos mesmos após o tratamento endovascular. Pacientes e métodos: Foram selecionados 30 pacientes consecutivos do Ambulatório de Cirurgia Vascular e Endovascular do HCFMRP-USP, no período de janeiro de 2104 a novembro de 2015, com aneurisma de aorta abdominal e com indicação para tratamento endovascular. As dosagens séricas e avaliações angiotomográficas foram feitas no pré-operatório e 6 meses após a intervenção. Resultados: Houve uma hiperexpressão do microRNA-1281 nos pacientes com aneurisma e uma significativa redução dos seus níveis séricos após a correção endovascular. A expressão do miRNA-1281 apresentou correlação positiva com o clearence de creatinina. Houve também correlação positiva da PCR com a presença do aneurisma, e com seu diâmetro e não houve alteração significativa da função renal mensurada através das dosagens séricas de uréia, creatinina e cálculo indireto de clearence. Conclusão: O estudo mostrou que o miRNA 1281 tem boa correlação com a evolução favorável pós-tratamento endovascular do AAA, não se observando o mesmo com a proteína C reativa. Novos estudos são necessários para validar e complementar tais achados.Introduction: Abdominal aortic aneurysm (AAA) is a prevalent and silent disease. Currently, the endovascular approach has been widely used and is the main technique due to the innumerable advantages. However, it has a higher rate of reintervention and requires periodic follow-up with tomography over the years, which increases its costs and has implications such as altered renal function besides the accumulation of radiation. Such conditions justify the search for possible biomarkers that may perhaps replace CT. Objectives: In this study, we sought to correlate the microRNA-1281, Creactive protein (CRP) and the renal function evaluation of individuals with AAA with their evolution after endovascular treatment. Patients and methods: We selected 30 consecutive patients from the Ambulatory of Vascular and Endovascular Surgery of the HCFMRP-USP, in the period from January of 2104 until November of 2015, with abdominal aortic aneurysm and with indication for endovascular treatment. Serum dosages were made preoperatively and 6 months after the intervention Results: There was a hyperexpression of the micro-RNA -1281 in patients with aneurysm and a significant reduction of their serum levels after endovascular correction. Expression of miRNA-1281 showed a positive correlation with creatinine clearence. There was also a positive correlation of CRP with the presence of the aneurysm, and with its diameter, and there was no significant alteration of renal function measured through serum urea, creatinine and indirect clearance calculations. Conclusion: The study showed that 1281 miRNAs may prove to be a potential biomarker for eventual follow-up of patients undergoing AAA endovascular repair. New studies are needed to validate and complement these findings.
11
Chamberlain, Ciara M. "Granzyme B in abdominal aortic aneurysm and aortic dissection." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/5584.
Повний текст джерелаАнотація:
An aneurysm is a permanent focal dilatation of an artery, often associated with
atherosclerosis and with a weakening of the vessel wall. An arterial dissection is when a tear
in the inner layer of the blood vessel causes blood to flow between the layers and force the
blood vessel apart. Aneurysms or dissections can result in rupturing of the vessel, leading to
excessive hemorrhaging and death if not immediately repaired. Granzyme B (GrB) is a
protein that is expressed and secreted by cytotoxic immune cells. GrB has been identified as
a key player in atherosclerosis both in the induction of apoptosis in target cells and the
degradation of extracellular matrix proteins. We generated GrB/apolipoprotein E (apoE)
double knockout (GrB/apoE-DKO) mice, and have shown that advanced atherosclerosis is
significantly reduced in GrB/apoE-DKO mice as compared to apoE-KO mice. Evaluation of
elastin staining indicated a loss of elastic tissue and medial thinning in the aortas of apoE-KO
mice that was restored when GrB was absent in the GrB/apoE-DKO mice.
Since medial thinning renders the aorta wall more susceptible to aneurysms or dissections,
we hypothesize that the absence of GrB will reduce the incidence of aneurysm formation and
dissection in GrB/apoE-DKO mice as compared to apoE-KO mice during angiotensin II
(angli) infusion.
To induce aortic dissections, 3-month-old C57 (wildtype), apoE-KO, and GrB/apoE-DKO
mice were implanted with an osmotic mini pump which released a dose of 1000ng/kg/min of
angli (or saline as a control) for 28 days. The mice were euthanized at 28 days, and the
aortas were removed and evaluated for gross morphology and, after cross sectional staining,
for histopathological lesions.
A significant reduction in aortic dissections and aneurysms was observed in GrB/apoE-DKO
mice as compared to apoE-KO mice treated with angII. Further, GrB deficiency
corresponds to a significant increase in survival at the 28 day time-point. Aneurysms and
dissections were not observed in the saline-treated groups or the angli-treated wild-type
controls. In conclusion, our studies suggest that GrB contributes to the loss of vessel wall
integrity and to the occurrence of aortic aneurysm and dissection.
12
Gopalakrishnan, Shyam Sunder. "Dynamics and Stability of Flow through Abdominal Aortic Aneurysms." Doctoral thesis, Université de Lyon 1, Ecole Centrale de Lyon, Lyon, 2014. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/245358.
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Carvalho, Adriana Camargo. "Niveis plasmaticos de vasopressina em cirugia de correção de aneurisma de aorta abdominal." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312004.
Повний текст джерелаАнотація:
Orientadores: Sebastião Araujo, Ana Terezinha GuillaumonDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-13T22:15:18Z (GMT). No. of bitstreams: 1 Carvalho_AdrianaCamargo_M.pdf: 1640507 bytes, checksum: d217bd19f4b6097e48dac1bb2f824e35 (MD5) Previous issue date: 2009
Resumo: Objetivos: Avaliar os níveis plasmáticos de vasopressina (AVP) em pacientes submetidos à correção cirúrgica não-complicada de aneurisma de aorta abdominal (AAA). Desenho: Estudo prospectivo, descritivo, observacional. Intervenções: Nenhuma. Local: Hospital de Clínicas da Unicamp. Métodos: A AVP plasmática foi mensurada por radio-imuno-ensaio em 22 pacientes não-consecutivos submetidos à correção cirúrgica convencional de AAA infra-renal, sob anestesia combinada (geral e epidural) nos seguintes tempos: pré-operatório (T0); 2h (T1) e 6h (T2) após o término da cirurgia; e nas manhãs do 1º (T3), 2º (T4) e 3º (T5) dia pós-operatório (PO). Algumas variáveis clínicas e laboratoriais de interesse foram registradas concomitantemente. Resultados: A idade média dos pacientes foi de 68,2±10,2 anos (variando de 49-82 anos), sendo 17 homens e 5 mulheres. Os níveis plasmáticos de AVP (média±DP pg/mL) estavam baixos e dentro da faixa de normalidade em T0 (1,4±0,7; controle), aumentando significativamente em T1 (62,6±62,9; p<0,001) e T2 (31,5±49,7; p<0,001), com uma queda exponencial a seguir, retornando aos níveis basais em T5 (2,1±3,8; p = NS). Correlações positivas e estatisticamente significativas foram encontradas entre a AVP e a glicemia, lactatemia e leucócitos sangüíneos, mas não com a pressão arterial sistêmica ou osmolaridade plasmática no PO. Conclusões: O padrão de aumento da AVP plasmática, com picos nas primeiras horas de PO nestes pacientes, sugere que esta resposta está diretamente relacionada ao trauma cirúrgico, mas não às alterações hemodinâmicas e da osmolaridade plasmática. A fisiopatologia deste padrão de resposta ao estresse é ainda obscuro, e merece investigações adicionais em procedimentos cirúrgicos gerais
Abstract: Objectives: To evaluate plasma vasopressin (AVP) levels in patients undergoing uncomplicated conventional abdominal aortic aneurysm (AAA) repair. Design: Prospective, descriptive, observational study. Interventions: None. Setting: A tertiary academic hospital at Campinas, Sao Paulo, Brazil. Methods: Plasma AVP concentrations were measured by radioimmunoassay in 22 nonconsecutive adult patients undergoing infra-renal AAA repair under combined general and epidural anesthesia at the following moments: pre-operative (T0); 2h (T1) and 6h (T2) after surgical procedure; and by the morning at the 1st (T3), 2nd (T4) and 3rd (T5) postoperative days. Some clinical and laboratory variables were concomitantly recorded. Results: Patients mean age was 68.2±10.2 years (ranging 49-82 years), with 17 males and 05 females. AVP plasma levels (mean±SD pg/mL) were low and within the normal range at T0 (1.4±0.7; control), showing a significant increase at T1 (62.6±62.9; p<0.001) and at T2 (31.5±49.7; p<0.001), with a marked progressive fall in the subsequent days, returning to basal levels at T5 (2.1±3.8; p = NS). Positive and statistically significant correlations were found between AVP levels and glycemia, lactatemia and white blood cells counts, but not with systemic arterial pressure or plasma osmolarity during postoperative period. Conclusions: The pattern of plasma AVP increasing, peaking during the 1st postoperative hours, suggests that this response is directly related to the surgical trauma, but not to hemodynamic and/or plasmatic osmolarity derangements. The pathophysiology of this pattern of stress response is still unclear, and deserves further investigation in general surgical procedures
Mestrado
Pesquisa Experimental
Mestre em Cirurgia
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Boyle, Jonathan Robert. "New perspectives in abdominal aortic aneurysm management." Thesis, University of Leicester, 2000. http://hdl.handle.net/2381/29606.
Повний текст джерелаАнотація:
A better understanding of the pathophysiology of abdominal aortic aneurysms has recently been established paving the way for potential targeted pharmacotherapy aimed at inhibiting the growth of small aneurysms. In particular the matrix metallopropteinase enzymes have been implicated in the destruction of the aortic wall. To this end the first part of this thesis investigates the potential therapeutic role of doxycycline, a non-specific metalloproteinase inhibitor, in an established model of aneurysmal disease. Subsequently the role of Amlodipine a calcium antagonist and metalloproteinase potentiator is investigated in the same model. Endovascular AAA repair is a new minimally invasive technique that allows treatment of aortic aneurysms without major abdominal surgery. The feasibility of this technique has been established, however a number of important questions remain unanswered. The second half of this thesis investigates the invasiveness of endovascular repair in comparison to conventional surgery. In particular the impact both procedures have on respiratory, cardiac, renal and metabolic responses is studied in comparative cohorts undergoing both conventional and endovascular AAA repair. Finally the implications of offering a tertiary referral service for AAA treatment is investigated. The results presented in this thesis demonstrate that doxycycline inhibits MMP activity and thus elastin destruction in a porcine model of aneurysmal disease. In the same model however, Amlodipine potentiates MMP activity and accelerates elastin degradation. There may be a therapeutic role for doxycycline in reducing the growth rate of small aneurysms. The clinical investigations of this thesis show that endovascular AAA repair attenuates the respiratory, cardiovascular, renal and metabolic responses associated with conventional aneurysm surgery. There were however still considerable insults from endoluminal surgery. Endovascular AAA repair may reduce morbidity and mortality rates after elective AAA surgery. The last experimental chapter illustrates that offering endovascular AAA repair as a tertiary centre has considerable clinical and financial implications. Finally a number of problems remain with endovascular AAA surgery which require evaluation by randomised controlled trial before its widespread use.
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Choke, Tieng Chek. "Molecular mechanisms of abdominal aortic aneurysm rupture." Thesis, St George's, University of London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511897.
Повний текст джерела
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Watton, Paul N. "Mathematical modelling of the abdominal aortic aneurysm." Thesis, University of Leeds, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411948.
Повний текст джерела
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Holmström, Ami. "Abdominal Aortic Aneurysm Screening : an Ethical Discussion." Thesis, Örebro universitet, Institutionen för medicinska vetenskaper, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-72994.
Повний текст джерелаАнотація:
Introduction: Abdominal aortic aneurysms (AAA) have a prevalence of approximately 2%, and are more common in men. AAAs are generally asymptomatic, but if ruptured and untreated, the mortality rate is close to 100%. Screening programs for AAAs are implemented in Sweden, the UK, and the US. This study describes the different views of AAA screening with a special emphasis on underlying ethical issues. Aim: To analyze the scientific background of AAA screening in order to be able to discuss its ethical basis. Methods: This was a qualitative literature study with an analysis of arguments using a hermeneutic method. Articles were obtained through a literature search and consisted of official articles, scientific articles, and debate articles. Results: A recent dissertation has questioned the value of AAA screening because of decreased AAA mortality and risk for overdiagnosis. However, most studies and official recommendations are in favor of AAA screening because disease specific mortality decreases and the screening program is considered cost-effective. Conclusion: This study shows that intellectual passion has created an unusually polarized discussion. It seems that benefit outweighs harm. Since AAA screening is the first screening program which could lead to the death of a previously asymptomatic individual, well founded informed consent is extremely important. Finally, both decisions to act and not to act have moral consequences.
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Abbas, Abeera. "Multimodality imaging of the abdominal aortic aneurysm." Thesis, King's College London (University of London), 2015. http://kclpure.kcl.ac.uk/portal/en/theses/multimodality-imaging-of-the-nabdominal-aortic-aneurysm(fcdd75c2-eb72-4623-9529-515004d32d8d).html.
Повний текст джерелаАнотація:
Age and hypertension lead to aortic remodeling and stiffness and are also major risk factors for abdominal aortic aneurysms (AAA). This study aimed to investigate: (i) the use of multimodal imaging to test the hypothesis that aneurysmal disease of the abdominal aorta is a remodeling response to aortic stiffness and systolic hypertension; (ii) the utility of a novel ultrasound-based device (AortaScan) for detection of AAA in the community setting. We used multimodality imaging tonometry and cardiovascular magnetic resonance imaging (CMR) to quantify pulse wave velocity (PWV, a measure of stiffness), in the aortic arch (Arch), thoracic aorta (TA) and the abdominal aorta (AA). Stiffness was also correlated with measures of calcification and metabolic activity measured on CT and PET/CT respectively. The thoracic aortae of patients with AAA were stiffer than those of sex matched controls. Although systolic hypertension was more common in AAA patients, multivariate analysis revealed that aortic stiffness and mean arterial pressure were associated with AAA disease. The likelihood of developing AAA disease increases >3-fold for 1m/sec increase in PWV. This data suggests that segmental stiffness is modified in the presence of AAA and provides further evidence that aneurysm formation may be an adaptive remodeling response to hypertension. The AortaScan can detect AAA without the need for a trained operator and has potential in a community-based screening programme. It would, however, need further technical improvement to increase sensitivity before it could be considered a replacement for trained screening personnel.
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Norrgård, Örjan. "Familial occurrence of abdominal aortic aneurysms." Doctoral thesis, Umeå universitet, Kirurgi, 1985. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-100555.
Повний текст джерелаАнотація:
The occurrence of clinically diagnosed and/or ruptured abdominal aortic aneurysms (AAAs) in the families of 220 patients with AAAs, treated at the Surgical Clinic, University Hospital of Umeå in the northern part of Sweden during the years 1965-82, was studied. A questionnaire concerning the blood relatives was answered by 87/89 patients. 16/87 patients (18%) had blood relatives with AAAs. In 14 families one blood relative was affected, and in 2 families two blood relatives were affected. First degree relatives were affected in 9/87 cases (10%), and second degree relatives in 7/87 cases (8%). 9/468 (1.9%) of the patients' brothers and sisters but only five of all their cousins had AAAs, and 7/204 (3.4%) of the dead brothers and sisters had died of ruptured AAAs. Concerning the patients who were not included in the letter survey at least 14/133had blood relatives with AAAs. However, the great majority of these patients were dead when the study was performed and could not be asked aboutthe occurrence of AAAs in their families. The patients with AAAs had significantly higher serum concentrations of triglyceride and (YLDL + LDL)-cholesterol and a significantly lower serum concentration of HDL-cholesterol than randomly selected healthy controls of the same sex and age as the patients. We also compared the distributions of genetic markers (HLA antigens, the blood group systems ABO, Rh, MNSs, P, Kell, Lewis and Duffy and the serum protein group systems haptoglobin, transferrin, group-specific component, complement C3, properdin factor and alpha-1-antitrypsin) in patients with AAAs with the distributions in controls and in some cases with the expected distributions according to the Hardy-Weinberg law. A significantly decreased frequency of Rh-negative individuals, and significantly increased frequencies of Kell-positi ve individuals, of MN heterozygotes and of heterozygotes concerning haptoglobin type was found. Furthermore, the aneurysm walls of patients with and without AAAs in the family were compared concerning the morphology, but no differences were found. We also studied the occurrence of collagen types I and III in the aneurysm walls, and the occurrence of vimentin and desmin in the smooth muscle cells of the aneurysm walls, but all these components were present in the aneurysm walls of both the patients with and those without AAAs in the family. To summarize the results, there seems to be an increased frequency of AAAs, and especially of ruptured AAAs, among the brothers and sisters of patients with AAAs. Elevated serum concentrations of triglyceride and (VLDL + LDL)- cholesterol and a lowered serum concentration of HDL-cholesterol seems to be common in patients with AAAs. There seems to be a hereditary predisposition to the development of AAAs, because we found associations with four different genetic markers (Rh, MN, Kell, haptoglobin group). However, there is probably no specific "familial" type of AAAs, because we found no differences between the patients with and those without AAAs in the family.Key words:S. 1-42: sammanfattning, s. 43-103: 5 uppsatser
digitalisering@umu
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Maroney, Roy Thomas. "Missed opportunities for the detection of abdominal aortic aneurysms : a retrospective study of eighteen patients presenting with a ruptured or acute symptomatic abdominal aortic aneurysm." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/25566.
Повний текст джерелаАнотація:
A ruptured abdominal aortic aneurysm (AAA) has a mortality of 80 percent. The majority of these cases present as medical emergencies, with 50 percent dying before they reach hospital. Twenty percent are not operated on because of an incorrect diagnosis and of the surviving 30 percent, there will be a peri-operative mortality of 40 percent. Thus only 20 percent of patients survive this condition. It is important to state that the long-term survival reported for patients undergoing AAA surgery approximates that of age-matched populations. This is in contrast to patients undergoing a coronary bypass procedure, where the long-term survival is affected by factors such as hypertension, angina and peripheral vascular disease. If the condition is diagnosed electively, the mortality rate is reduced to less than 5 percent. The researcher obtained the records of 18 patients who had presented to the vascular service at the New Kingsbury Hospital with a diagnosis of a ruptured or acute symptomatic AAA. He interviewed the referring family doctor and also obtained information from the case records to determine whether there were missed opportunities for the detection of such aneurysms. The results of the research showed that 12 general practitioners (GP's) out of a group of 13, were unaware that abdominal ultrasound is a highly specific and sensitive method for detecting AAA's. Only one of the group of 13 GP's regularly screens for AAA. The diagnosis of AAA was missed in 12 of the 18 patients. In this series the mean diameter of the aorta was 7,67 cm which is considered to be easily palpable. Five of the patients were referred to specialists for incidental reasons and they all failed to detect the AAA. The majority of patients with AAA's have at least 2 associated risk factors. The patients consulted their GP at least 5 times over the 24 month period. The GP's are not aware of the different modes of presentation, associated risk factors nor the value of screening for AAA's. Ten of the group of 13 GP's profess to engage in some form of Continuing Medical Education (CME). I have suggested a few guidelines to encourage family physicians to screen for AAA in all males over the age of 60, especially if they have risk factors, such as hypertension, a current or former cigarette smoker, coronary artery disease, peripheral vascular disease and a family history of AAA. The examination should include a thorough abdominal palpation and referral for an abdominal ultrasound examination to obtain the precise diameter of the AAA as treatment depends on the size of the AAA.
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Hua, Fang. "Role of angiotensin II and inflammatory cells in the development of human abdominal aortic aneurysm /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18409.pdf.
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Krenzien, Felix, Ivan Matia, Georg Wiltberger, Hans-Michael Hau, Moritz Schmelzle, Sven Jonas, Udo X. Kaisers, and Peter T. Fellmer. "Early prediction of survival after open surgical repair of ruptured abdominal aortic aneurysms." Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-156960.
Повний текст джерелаАнотація:
Background: Scoring models are widely established in the intensive care unit (ICU). However, the importance in patients with ruptured abdominal aortic aneurysm (RAAA) remains unclear. Our aim was to analyze scoring systems as predictors of survival in patients undergoing open surgical repair (OSR) for RAAA. Methods: This is a retrospective study in critically ill patients in a surgical ICU at a university hospital. Sixty-eight patients with RAAA were treated between February 2005 and June 2013. Serial measurements of Sequential Organ Failure Assessment score (SOFA), Simplified Acute Physiology Score II (SAPS II) and Simplified Therapeutic Intervention
Scoring System-28 (TISS-28) were evaluated with respect to in-hospital mortality. Eleven patients had to be excluded from this study because 6 underwent endovascular repair and 5 died before they could be admitted to the ICU. Results: All patients underwent OSR. The initial, highest, and mean of SOFA and SAPS II scores correlated significant
with in-hospital mortality. In contrast, TISS-28 was inferior and showed a smaller area under the receiver operating curve. The cut-off point for SOFA showed the best performance in terms of sensitivity and specificity. An initial SOFA score below 9 predicted an in-hospital mortality of 16.2% (95% CI, 4.3–28.1) and a score above 9 predicted an
in-hospital mortality of 73.7% (95% CI, 53.8–93.5, p < 0.01). Trend analysis showed the largest effect on SAPS II. When the score increased or was unchanged within the first 48 h (score >45), the in-hospital mortality rate was 85.7% (95% CI, 67.4–100, p < 0.01) versus 31.6% (95% CI, 10.7–52.5, p = 0.01) when it decreased. On multiple regression analysis, only the mean of the SOFA score showed a significant predictive capacity with regards to mortality (odds ratio
1.77; 95% CI, 1.19–2.64; p < 0.01). Conclusion: SOFA and SAPS II scores were able to predict in-hospital mortality in RAAA within 48 h after OSR. According to cut-off points, an increase or decrease in SOFA and SAPS II scores improved sensitivity and specificity.
23
Bailey, Marc Aaron. "Store operated calcium entry in abdominal aortic aneurysm." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/13678/.
Повний текст джерелаАнотація:
Background: Abdominal Aortic Aneurysm (AAA) is a focal dilatation of the abdominal aorta that progresses over time and eventually ruptures. Surgery is risky but a medical therapy is lacking. Vascular smooth muscle cells (VSMC) are apoptotic in end-stage AAA. There is evidence that they undergo pathological remodelling in early disease. My novel hypothesis is that reduction of this pathological vascular remodelling will be beneficial. Platelet derived growth factor (PDGF) drives VSMC remodelling through IP3 generation, ER Ca2+ store release and store operated Ca2+ entry (SOCE) via the plasma membrane Orai1 channel. In this thesis I will explore the possibilities of small-molecule Orai1 inhibition to attenuate VSMC remodelling and AAA growth. Methods & Results: A novel Orai1 blocker, JPIII is used throughout the thesis. Orai1 was functionally expressed in AAA VSMC and could be inhibited by JPIII which had nanomolar potency against SOCE and reduced downstream proliferation, migration and apoptosis. JPIII was also effective in rodent VSMC against SOCE and the downstream NFAT activation and was selective for Orai1 in a Cerep selectivity screen. In vivo, three murine models of AAA were used (AngII, CaCl2 and PPE); VSMC remodelling and Orai1 upregulation assessed histologically were apparent in all three models. JPIII treatment reduced AAA VSMC remodelling (by histology) and AAA lumen dimensions (by histology and in vivo ultrasound). JPIII was also effective against AAA progression in mice with established AAA. No major toxic flags were demonstrated but JPIII was a pan CYP450 inhibitor. It was possible to improve the PK of the molecule without loss of the AAA effect. Conclusion: These data suggest it is possible to modify the VSMC remodelling response in AAA through Orai1 inhibition with a small molecule blocker with no major off target effects in mice. This is a promising starting point for translational development of a therapy for human patients.
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Tambyraja, Andrew Laksman. "Prediction of outcome after abdominal aortic aneurysm rupture." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/29391.
Повний текст джерелаАнотація:
Existing risk models and predictive variables for outcome were validated on a retrospective cohort of consecutive patients with ruptured AAA. These data were also used to design novel prognostic index for outcome prediction. A prospective cohort of consecutive patients was used to further validate these scoring systems, examine novel prognostic variables and determine functional outcome. Existing risk scoring instruments for patients with ruptured AAA lack validity. Analysis of preoperative variables in patients with ruptured AAA shows that absolute surgical futility cannot be predicted. However, in-hospital hypotension (<90mmHg), reduced Glasgow Coma Scale (<15) and anaemia (<9g/dL) are associated with preoperative death. When these risk factors are equally weighted and combined to create a novel risk scoring instrument (Edinburgh Ruptured Aneurysm Score-ERAS), three discriminatory tiers of risk are demonstrable. The validity of this risk instrument is confirmed on prospective data. Examination of novel perioperative prognostic variables shows that elevated cardiac troponin I, with or without clinically apparent cardiac dysfunction, is predictive of death after ruptured AAA repair. However, although ruptured AAA are associated with an early elevation in inflammatory biomarkers, these do not appear to confer additional prognostic value. Furthermore, for the first-time, prospective study shows that patients who survive ruptured AAA repair achieve a good recovery in terms of functional outcome within six months of operation. Surgical futility cannot be predicted prior to operation in patients with AAA. However, the ERAS shows potential as a preoperative prognostic index in patients with ruptured AAA.
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Tegler, Gustaf. "Abdominal Aortic Aneurysm : Molecular Imaging Studies of Pathophysiology." Doctoral thesis, Uppsala universitet, Kärlkirurgi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-194663.
Повний текст джерелаАнотація:
The pathological process behind abdominal aortic aneurysm (AAA) formation is poorly understood and difficult to study. The aim of the thesis was to study the pathophysiology of AAA formation with positron emission tomography (PET) technology, a molecular imaging technique, allowing in vivo studies of pathophysiological changes. In study I 18F-FDG, a glucose analogue, was tested. It had previously been reported as a useful tracer studying inflammation in AAAs. These studies included, however, foremost large, symptomatic, and inflammatory AAAs. In the present study on five small and seven large asymptomatic AAAs, no increase in 18F-FDG uptake could be revealed in vivo. In study II 11C-PK11195, a macrophage tracer, and 11C-D-deprenyl, an unspecific inflammatory tracer, previously never tested on asymptomatic AAAs, were tested in vivo on five and 10 AAA-patients respectively, without signs of increased levels of inflammatory activity in the aorta. In study III several tracers were screened in vitro through autoradiography on AAA tissue. [18F]fluciclatide, targeting the integrin αVβ3 receptor upregulated in angiogenesis, was the only tracer with an increased uptake. In study IV [18F]fluciclatide-autoradiography was performed on AAA tissue from five patients and non-aneurysmal aortic tissue obtained from five age and sex matched organ donors. The study showed a 56% increased specific uptake in AAA, although not significant (P=0.136). Immunohistochemical revealed inflammatory cell foci in close relation to the vessels. In conclusion, PET has potential to elucidate the pathophysiology of AAA formation. For the large group of small asymptomatic AAAs, 18F-FDG is not suitable, as the chronic inflammation in asymptomatic AAA is not sufficiently metabolically active. Furthermore, 11C-PK11195 and 11C-D-deprenyl were unable to show the chronic inflammation seen in asymptomatic AAA. The interesting finding with uptake of [18F]fluciclatide showed that angiogenesis may be imaged in large asymptomatic AAAs in vitro, through the integrin αVβ3 receptor. Thus, it is likely that future studies of the role of angiogenesis in AAA formation in vivo, in small AAAs, could use this target site. The development of an integrin αVβ3 receptor tracer, preferably with higher affinity, is in progress for further in vitro and in vivo studies.
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Olofsson, Anna. "Capturing circulating microRNAs in abdominal aortic aneurysm disease." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-296450.
Повний текст джерелаАнотація:
The current study focuses on finding differential expression between circulating microRNAs in plasma from patients with abdominal aortic aneurysms compared to un-diseased individuals by using a qPCR-based array. In addition, we evaluated the expression of deregulated microRNAs in human tissue samples as well as microarray data from two independent mouse models of aneurysm development. Fifteen miRNAs were found to be significantly differentially expressed, with four of them surviving multiple testing. Interestingly all four of them were substantially different in murine aneurysm development.
27
Potseluev, V., and M. Kora. "Anesthesia in endovascular abdominal aortic aneurysm (AAA) repair." Thesis, Sumy State University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/58598.
Повний текст джерелаАнотація:
Introduction: endovascular AAA repair can be done using different anesthetic techniques,
such as general anesthesia, regional block, and local anesthesia associated with sedation. For successful anesthetic management, it is important to select the best approach with an understanding of the patient's health status.
28
Mani, Kevin. "Abdominal aortic aneurysm epidemiological and health economic aspects /." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-110810.
Повний текст джерела
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Mascoli, Chiara <1983>. "Abdominal aortic aneurysm treatment in Emilia Romagna region." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9291/1/mascoli-chiara-tesi.pdf.
Повний текст джерелаАнотація:
Introduction. Elective endovascular repair (EVAR) of abdominal aortic aneurysm (AAA) has been performed with increasing frequency due to lower 30-day morbidity and mortality compared with open surgical repair(OSR). Similar advantages are reported for ruptured AAAs.
Aim of the study was to report the frequencies of EVAR/OSR in elective and acute setting and 30-day outcomes, in two Italian Vascular Surgery of Emilia-Romagna-Region(VS-ERR).
Methods. All patients undergoing AAA repair in two VS-ERR (2015-2019), were prospectively collected. Pre-operative, procedural and post-operative data were retrospectively analyzed.
Percentage of EVAR/OSR were evaluated for overall, elective and acute patients. Technical-success (TS), intra-operative mortality and procedure-related adverse events (PAE) were assessed. Reinterventions, mortality&morbidity were assessed at 30-day. Results of EVAR and OSR were compared. Reasons of EVAR ineligibility were also investigated and compared.
Results. Overall 878 patients underwent AAA repair, 736 in elective (EVAR/OSR:80.4%/19.6%) and 142 in acute setting (EVAR/OSR:71.1%/28.9%).
Overall TS was 95.8%, PAE were reported in 9.1% of patients. Overall intraoperative mortality was 0.5%. Post-operative medical complications were reported in 21.2% patients. The mean hospitalization was 6.711.08 days. Overall 30-day-reinterventions and mortality were 3.9% and 4.2%, respectively.
In elective-setting, TS was similar between groups(P=.18). OSR had more PAE(P<.001) vs EVAR. There was no difference of intraoperative mortality(P=.62). EVAR had shorter hospitalization(P<.001), less 30-day reintervention(P<.001) and mortality(P<.001) vs OSR.
In acute-setting, no significant differences of TS(P=.56) and PAE(P=.18) between groups were observed. OSR had more perioperative medical complications(P<.001) and higher rate of 30-day mortality(P<.001) vs EVAR.
The main reason of EVAR exclusion was anatomical unsuitability(94.4%) in elective-setting while logistic cause(61%) in acute-setting.
Conclusion. EVAR has progressively increased for elective more than for acute setting. The misalignment of the VS-ERR from literature evidence in acute setting is principally due to logistic reason. According our data, the management of this subgroup of patients, should be improved.
30
Nordon, Ian Michael. "Mining the proteome of abdominal aortic aneurysms." Thesis, St George's, University of London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.546777.
Повний текст джерела
31
Forester, Nerys Dawn. "Mechanisms of inflammation in abdominal aortic aneurysms." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417894.
Повний текст джерела
32
Norwood, Michael Geoffrey Austin. "Inflammatory responses in abdominal aortic aneurism repair." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/29473.
Повний текст джерелаАнотація:
Introduction: Abdominal aortic aneurysm (AAA) repair is associated with a systemic inflammatory response. Ischaemia-reperfusion injury (IRI) to the gastrointestinal tract and lower limbs plays an important role in the initiation and mediation of this inflammatory response. I investigate which of these regions plays the most significant role in the initiation of the inflammatory response. The null hypothesis for this thesis is that there is no difference in the contributions made by the gastrointestinal tract and lower limbs to the systemic inflammatory response.;Method: Patients undergoing elective AAA repair were recruited and had blood sampled from the radical artery, femoral vein, portal vein, inferior mesenteric vein and inferior vena cava at induction of anaesthesia (systemic samples only), immediately prior to aortic clamping, immediately prior to aortic clamp removal (ischaemia) and after 30 minutes of reperfusion. Control patients undergoing major abdominal surgery were included to investigate the inflammatory response in patients undergoing major operations but without IRI.;Results: 46 patients with AAA, and 10 controls were studied. The majority of patients (61%, n=28) demonstrated a positive inflammatory response, as represented by the development of the Systemic Inflammatory Responses Syndrome (SIRS), and increases in the inflammatory markers described. Patients exhibited high levels of Interleukin-6 in the venous effluent of the gastrointestinal tact (P=0.001), and high numbers of activated neutrophils in the venous effluent from the lower-limbs (P=0.013) during reperfusion.;Conclusions: The work of this thesis confirms that patients undergoing AAA repair exhibit an inflammatory response. Significant differences in regional inflammatory responses were also demonstrated, and therefore the null hypothesis was rejected. This suggests that during AAA repair, the gastrointestinal tract is responsible for Interleukin-6 production, and that neutrophil activation occurs in the lower-limbs.
33
Monsur, Kazi. "Cellular and molecular mechanisms in abdominal aortic aneurysm growth and rupture /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-558-5/.
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34
Brekken, Reidar. "Ultrasound-based Estimation of Strain in Abdominal Aortic Aneurysm." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for sirkulasjon og bildediagnostikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19999.
Повний текст джерелаАнотація:
Abdominal aortic aneurysm (AAA) is a vascular disease resulting in a permanent local dilatation of the abdominal aorta. Different studies estimate the prevalence of AAA to 1.3-8.9% of men and 1.0-2.2% of women over 60 years of age. Risk factors include smoking, hypertension, high serum cholesterol, diabetes, and family history. The weakening of the wall and altered wall stress associated with aneurysm formation and progression may eventually lead to aneurysm rupture, which causes haemorrhage and severe blood loss and is associated with very high mortality. AAA is responsible for 1.3% of deaths among men aged 65-85 in developed countries. Elective repair of asymptomatic AAA is recommended when the risk of rupture is estimated to exceed the risk associated with repair. Currently, best clinical practice is to recommend repair when the maximum diameter of the aneurysm exceeds 50-55 mm or increases rapidly. This is a population-based criterion, meaning that in average, an aneurysm with diameter exceeding this criterion is more likely to rupture than to experience complications with repair. Individually, however, some aneurysms rupture before 50 mm, while several aneurysms larger than 55 mm are still intact. More patient-specific information about the state of the individual aneurysm is therefore warranted. In this PhD thesis I have developed and investigated concepts and methods for ultrasound based strain estimation in AAA. The physiological motivation is that progression of aneurysm is associated with altered wall tissue composition, which leads to altered elastic properties, and altered wall stress (geometry and flow conditions). The underlying hypothesis is that it may be possible to detect and quantify this alteration from dynamic ultrasound images, and through that predict further progression. We have developed a method for estimation of cyclic circumferential strain from 2D ultrasound. The method relies on the user to define the wall in an ultrasound image, and then automatically tracks a number of points in the wall over the cardiac cycle based on correlation between frames. The relative change in distance between neighboring points are used as a measure for strain estimation. Inhomogeneous strain values were found along the circumference of the aneurysms, suggesting that additional information could be obtained compared to using diameter alone. The method was further used for investigating strain in aneurysms before and after endovascular aortic repair (EVAR) in ten patients. Since insertion of a stentgraft reduces the load imposed on the wall, a successful EVAR should result in reduced strain. The results showed a clear reduction, which means that the expected reduction was indeed detectable using our method. The study included a limited patient material, and it remains to investigate if the strain values can be used for predicting clinical outcome after EVAR. Because only a limited part of the aneurysm can be imaged in each cross-sectional view, we demonstrated a method for visualizing the circumferential strain from several image planes together in a 3D model using navigation technology. The 3D model may enhance interpretation of results by relating circumferential strain from several parts of the aneurysm to a 3D geometry. This is also an important step towards integration with wall stress simulations for adding more patient specific information. Abdominal images may have relatively low signal to noise ratios, which will negatively influence the performance of the correlation based tracking method. Before larger clinical trials are initiated, it is therefore important to investigate the quality of the strain estimates obtained by the method. We developed a simulation model, for simulation of wall motion due to a time-varying blood pressure, and for simulation of ultrasound images including speckle, direction dependent reflection and absorption. The simulation model is an important part of future evaluation and tuning of the strain method. Further refinement includes implementation of the processing method on an ultrasound scanner for real-time data analysis, which would benefit workflow and make it easier to find the most relevant image planes during investigation. Also, strain estimation from real-time 3D ultrasound is interesting for evaluating several strain components. Finally, clinical trials must be implemented for further investigating potential correlation between strain and clinically relevant parameters, including formation, growth and rupture of AAA.
35
Grytsan, Andrii. "Abdominal aortic aneurysm inception and evolution - A computational model." Doctoral thesis, KTH, Biomekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-197289.
Повний текст джерелаАнотація:
Abdominal aortic aneurysm (AAA) is characterized by a bulge in the abdominal aorta. AAA development is mostly asymptomatic, but such a bulge may suddenly rupture, which is associated with a high mortality rate. Unfortunately, there is no medication that can prevent AAA from expanding or rupturing. Therefore, patients with detected AAA are monitored until treatment indication, such as maximum AAA diameter of 55 mm or expansion rate of 1 cm/year. Models of AAA development may help to understand the disease progression and to inform decision-making on a patient-specific basis. AAA growth and remodeling (G&R) models are rather complex, and before the challenge is undertaken, sound clinical validation is required. In Paper A, an existing thick-walled model of growth and remodeling of one layer of an AAA slice has been extended to a two-layered model, which better reflects the layered structure of the vessel wall. A parameter study was performed to investigate the influence of mechanical properties and G&R parameters of such a model on the aneurysm growth. In Paper B, the model from Paper A was extended to an organ level model of AAA growth. Furthermore, the model was incorporated into a Fluid-Solid-Growth (FSG) framework. A patient-specific geometry of the abdominal aorta is used to illustrate the model capabilities. In Paper C, the evolution of the patient-specific biomechanical characteristics of the AAA was investigated. Four patients with five to eight Computed Tomography-Angiography (CT-A) scans at different time points were analyzed. Several non-trivial statistical correlations were found between the analyzed parameters. In Paper D, the effect of different growth kinematics on AAA growth was investigated. The transverse isotropic in-thickness growth was the most suitable AAA growth assumption, while fully isotropic growth and transverse isotropic in-plane growth produced unrealistic results. In addition, modeling of the tissue volume change improved the wall thickness prediction, but still overestimated thinning of the wall during aneurysm expansion.Bukaortaaneurysm (AAA) kännetecknas av en utbuktning hos aortaväggen i buken. Tillväxt av en AAA är oftast asymtomatisk, men en sådan utbuktning kan plö̈tsligt brista, vilket har hög dödlighet. Tyvärr finns det inga mediciner som kan förhindra AAA från att expandera eller brista. Patienter med upptä̈ckt AAA hålls därför under uppsikt tills operationskrav är uppnådda, såsom maximal AAA-diameter på 55 mm eller expansionstakt på 1 cm/år. Modeller för AAA-tillväxt kan bidra till att öka förståelsen för sjukdomsförloppet och till att förbättra beslutsunderlaget på en patientspecifik basis. AAA modeller för tillväxt och strukturförändring (G&R) är ganska komplicerade och innan man tar sig an denna utmaning krävs de god klinisk validering. I Artikel A har en befintlig tjockväggig modell för tillväxt av ett skikt av en AAA-skiva utö̈kats till en två-skiktsmodell. Denna modell återspeglar bättre den skiktade strukturen hos kärlväggen. Genom en parameterstudie undersö̈ktes påverkan av mekaniska egenskaper och G&R-parametrar hos en sådan modell för AAA-tillväxt. I Artikel B utvidgades modellen från Artikel A till en organnivå-modell för AAA-tillväxt. Vidare inkorporerades modellen i ett “Fluid–Solid–Growth” (FSG) ramverk. En patientspecifik geometri hos bukaortan användes för att illustrera möjligheterna med modellen. I Artikel C undersöktes utvecklingen av patientspecifika biomekaniska egenskaper hos AAA. Fyra patienter som skannats fem till åtta gånger med “Computed Tomography-Angiography” (CT-A) vid olika tillfällen analyserades. Flera icke triviala statistiska samband konstaterades mellan de analyserade parametrarna. I Artikel D undersöktes effekten av olika tillväxt-kinematik för AAA tillväxt. En modell med transversellt-isotrop-i-tjockleken-tillväxt var den bäst lämpade för AAA tillväxt, medans antagandet om fullt-isotrop-tillväxt och transversellt-isotrop-i-planet-tillväxt producerade orimliga resultat. Dessutom gav modellering av vävnadsvolymsförändring ett förbättrat väggtjockleks resultat men en fortsatt överskattning av väggförtunningen under AAA-expansionen.
QC 20161201
36
Milne, Alan Anderson. "Coagulopathy and haemostasis in surgery for abdominal aortic aneurysm." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/21422.
Повний текст джерелаАнотація:
Coagulation studies were performed in a series of 24 patients with asymptomatic abdominal aortic aneurysm. Levels of fibrinogen were high but within the normal range, and there was no evidence of systemic activation of the soluble coagulation or fibrinolytic systems. Coagulation studies were performed in a series of six patients undergoing elective aortic aneurysm repair. It was found that thrombin, fibrinolytic and platelet activation increases during the period of initial dissection in a time dependent manner. After the administration of heparin and the application of the aortic cross clamp, thrombin, fibrinolytic and platelet activation reduced. After reperfusion there was an increase in platelet activation which correlated with the duration of cross-clamping. Coagulation studies were performed in a series of 22 patients presenting with ruptured aortic aneurysm. At time of admission there was marked activation of platelets and thrombin in all patients which increased greatly by the end of operation. Platelet count at the end of operation was significantly lower in patients who died than in survivors. Samples of subcutaneous fat and skeletal muscle were taken at the start of operation in six patients with ruptured aneurysm. Transmission electron microscopy was used to examine the endothelial cells in small vessels in these samples. When compared with samples from six control patients undergoing elective aortic surgery it was found that there were significant ultrastructural differences in the endothelial cells from patients with rupture. A randomised controlled study of fibrin sealant as a topical haemostatic agent at vascular anastomoses was carried out in 57 patients undergoing aortic aneurysm repair, carotid endarterectomy or arterial bypass graft using polytetrafluoroethylene bypass graft. The time taken to achieve haemostasis at the anastomoses was significantly reduced in patients treated with fibrin sealant. The reduction was most marked in patients undergoing carotid endarterectomy.
37
Grytsan, Andrii. "Computational model of abdominal aortic aneurysm inception and evolution." Licentiate thesis, KTH, Biomekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-142649.
Повний текст джерелаАнотація:
Incidence of abdominal aortic aneurysm (AAA) is increasing in the aging society of the western world. Development of AAA is mostly asymptomatic and is characterized by a bulge in the abdominal aorta. However, AAA may suddenly rupture, which results in an internal bleeding associated with a high mortality rate. Patients with AAA undergo regular screening until treatment indication. To date, statistical criteria are used to decide whether the risk of rupture exceeds the risk of intervention. Models of AAA development help to understand the disease progression and to yield patient-specific criterion for AAA rupture. Up to date, sophisticated models of AAA development exist. These models assume the abdominal aorta as a thin-walled structure, which saves the computational effort. This thesis aims at investigating the importance of employing a thick-walled model of the aorta. The effects on AAA development that cannot be captured with a thin-walled model are of interest. In Paper A, the thick-walled model of growth and remodeling of one layer of a AAA slice has been extended to a two-layered model. The parameter study has been performed to investigate the influence of mechanical properties and growth and remodeling (G&R) parameters of two individual layers on the gross mechanical response and G&R of the artery. It was concluded that the adventitia acts to protect the arterial wall against rupture even in pathological state. In Paper B, the model was extended to an organ level model of AAA development. Furthermore, the model was incorporated into a so-called Fluid-Solid-Growth (FSG) framework, where the AAA development is loosely coupled to the blood flow conditions such as wall shear stress. One patient-specific geometry of the abdominal aorta is used to illustrate the model capabilities. A transmurally non-uniform distribution of the strains of individual arterial constituents was observed. In addition, an increased aneurysm tortuosity was observed in comparison to a thin-walled approach. These findings signify the importance of a thick-walled approach to model the aneurysm development. Finally, the proposed methodology provides a realistic basis to further explore the growth and remodeling of AAA on a patient-specific basis.QC 20140311
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Ashton, John Hardy. "Polymeric Endo-Aortic Paving (PEAP): Initial Development of a Novel Treatment for Abdominal Aortic Aneurysms." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/204293.
Повний текст джерелаАнотація:
Abdominal aortic aneurysm (AAA) is a prevalent disease in developed countries. While endovascular aneurysm repair is fairly successful, it has shortcomings. Polymeric endoluminal paving and sealing is a method that has previously been developed to treat a range of diseases. Our goal is to further develop this technique to treat AAA, a process we have named polymeric endo-aortic paving (PEAP). We hypothesize that PEAP will overcome many of the limitations associated with EVAR by providing a minimally invasive treatment which can be used on patients with complicated AAA geometries and reducing incidence of migration and endoleak. Additionally, we plan to incorporate drug delivery into PEAP to improve efficacy. The purpose of this work was to evaluate a potential graft material for PEAP and to develop a thrombus mimic which will aid in further PEAP development. Blends of polycaprolactone/polyurethane (PCL/PU) were assessed by characterizing their mechanical, thermoforming, and degradation properties. PCL/PU grafts have a similar stiffness to aortic tissue and can be thermoformed at temperatures approaching 37 degrees C. Blending PCL with PU significantly reduces PCL's degradation. An anisotropic hyperelastic strain energy function was developed for the PCL/PU blends and finite element modeling (FEM) was used to show that stress reduction on the AAA wall that can be achieved by PEAP is similar to current EVAR. Stiffness varies throughout the AAA thrombus, and thrombus mimics were developed that have similar stiffness, components, and structure to native AAA thrombus.
39
Solanich, Valldaura Teresa. "Síndrome compartimental abdominal en aneurismas de aorta abdominal rotos." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/665385.
Повний текст джерелаАнотація:
Introducción:
Los aneurismas de aorta abdominal rotos (AAAR) presentan una alta tasa de mortalidad, incluso aquellos pacientes que sobreviven a la cirugía (32 al 80%1-4). El fallo de varios órganos en el postoperatorio inmediato supone una causa frecuente de muerte. El síndrome compartimental abdominal (SCA) se presenta en un 30-53%, independientemente de la técnica terapéutica realizada (cirugía abierta o endovascular), pudiendo comportar un fallo multiorgánico, con una mortalidad de más del 70%(3). El SCA es un factor predictor de mortalidad en los AAAR, su prevención, detección y tratamiento mediante laparotomía descompresiva puede aumentar la supervivencia.
El objetivo del presente estudio ha sido determinar la supervivencia a 30 días de los pacientes intervenidos de aneurisma de aorta abdominal rotos, los factores de riesgo del síndrome compartimental abdominal y analizar los resultados del cierre abdominal diferido.
Material y métodos:
Estudio observacional retrospectivo de pacientes intervenidos de AAAR en el servicio de Angiología y Cirugía Vascular del Hospital Universitari Parc Taulí entre 2002 y 2016.
Se consideró AAAR aquellos pacientes con extravasación de sangre o hematoma fuera del AAA en la tomografía computerizada realizada preoperatoriamente, y/o el hallazgo de hematoma fuera del AAA durante la cirugía abierta.
Se diagnosticó de SCA aquellos pacientes que cumplían los parámetros establecidos por la WSACS o aquellos pacientes en que no pudo ser posible el cierre abdominal primario a criterio del cirujano vascular.
Se registraron variables demográficas, tipo de intervención, cierre abdominal diferido, factores de riesgo de SCA pre-intra-postoperatorios y supervivencia a 30 días.
Resultados:
Se incluyeron 61 pacientes de 87 elegibles, 39 cirugía abierta y 22 endovascular.Se excluyeron los pacientes con AAAR no tributarios de intervención. La mortalidad global intra-postoperatoria fue del 54%, siendo del 66,7% para la cirugía abierta y del 31,8% en la cirugía endovascular (p=0,009)
Se pudieron analizar los resultados postoperatorios de 43 pacientes que sobrevivieron a la cirugía, 21 cirugía abierta (48,8%) y 22 endovascular (51,2%). La supervivencia postoperatoría global a 30 días fue del 67,4% ( 61,9% cirugía abierta y 72,7 % endovascular).
Los factores de riesgo del SCA más frecuentes fueron: perfusión de >5 litros, coagulopatía, transfusión > 6 concentrados de hematies y la acidosis metabólica.
En el grupo de cirugía abierta: 12 presentaron SCA y 4 fueron éxitus. 9 no presentaron SCA, siendo éxitus 4. (p=0,604). En el grupo endovascular, 6 casos presentaron SCA, siendo éxitus 4, mientras que de los 16 casos que no presentaron SCA, 3 fueron éxitus (p=0,032)
En el grupo de cirugía abierta: en 9 casos se dejó el abdomen abierto (42,9%) y en 12 se cerró de forma primaria. El cierre abdominal diferido comportó un incremento de la supervivencia (88,9% versus 41,7%). En el grupo endovascular: en 6 casos se procedió a laparotomia descompresiva en el mismo acto quirúrgico, esta laparotomia descompresiva no supuso un incremento de la supervivencia (42,9% versus 87,5%)
Conclusiones:
En nuestra serie en el grupo de cirugía abierta el síndrome compartimental abdominal no incrementó la mortalidad.
El síndrome compartimental abdominal incrementó la mortalidad en el grupo de cirugía endovascular.
La mortalidad intraoperatoria de los aneurismas de aorta abdominal rotos fue mayor en el grupo de cirugía abierta.
No hallamos diferencias significativas en cuanto a la mortalidad postoperatoria de los aneurismas de aorta abdominal rotos según el tipo de cirugía.
Los factores de riesgo de síndrome compartimental abdominal han sido: perfusión >5 litros, coagulopatía en el período postoperatorio inmediato, transfusión >6 concentrados de hematies y acidosis metabólica intraoperatoria o postoperatoria immediata.
La laparotomía descompresiva primaria incrementa la supervivencia en el grupo de ciru-gía abierta no así en el grupo de cirugía endovascular.Introduction: Ruptured abdominal aortic aneurysms (RAAA) carry a high mortality. Patients who survive surgery have mortality rates of 32 to 80%1-4). Multi-organ failure during the immediate postoperative period is a very common cause of death. Abdominal compartment syndrome (ACS) is present in 30-53% of cases and represents a frequent cause of multi-organ failure with both endovascular and open inter-ventions, which accounts for 70% of deaths (3). ACS is an independent predictor of mortality in RAAA and its prevention, detection and treatment with decompressive laparotomy can increase survival. The aim of the present study was to analyse 30-day survival of patients undergoing RAAA repair, the presence of risk factors for ACS and RAAA and the results obtained with delayed abdominal closure. Material and methods: A retrospective observational study was designed, with the inclusion of patients undergoing RAAA repair between 2002 and 2016 in the Angiology and Vascular Surgery service, at the Hospital Uni-versitari Parc Taulí. RAAA was defined as the extravasation of blood or haematoma outside the wall of the abdominal aortic aneurysm (AAA) in computed tomography (CT) angiography and/or evidence of haematoma outside the AAA during the surgery. The presence of ACS was established according to the parameters established by the WSACS or when primary abdominal closure could not be performed at the discretion of the vascular surgeon. Demographic variables, type of surgery, delayed abdominal closure, pre-, intra- and postoperative ACS risk factors and 30-day survival were collected. Results: A total of 61 patients were included out 85 eligible: 39 open and 22 endovascular surgeries.Patient not submitted to repair were excluded. Overall intra- and postoperative mortality was 54% (66.7% with open surgery and 31.8% with endovascular surgery (p=0.009)). The postoperative results of 43 patients who survived surgery were analysed: 21 (48.8%) with open surgery and 22 (51.2%) with endovascular surgery. Overall 30-day postoperative survival was 67.4% (61.9% with open surgery and 72.7 with endovascular surgery). The most frequent risk factors for abdominal compartment syndrome were: perfusion >5 litres, coag-ulopathy, transfusion > 6 units of packed red blood cells and metabolic acidosis. In the open surgery group: 12 presented ACS, 4 of which died, and 4 of the 9 patients who did not present ACS died (p=0.604). In the endovascular surgery group, 6 patients presented ACS, 4 of which died, and 3 of the 6 patients who did not present ACS died (p=0.032). Of the patients who underwent OS, the abdomen was left open in 9 cases (42.86%), and primary abdominal closure was performed in 12. Delayed abdominal closure increased survival (88.9% vs. 41.7%). Six patients in the endovascular group had decompressive laparotomy during the same sur-gical procedure. Decompressive laparotomy did not increase survival in the endovascular surgery group (42.9% vs. 87.5%). Conclusions: Abdominal compartment syndrome did not increase mortality in the open surgery group. Abdominal compartment syndrome increased mortality in the endovascular surgery group. Intraoperative mortality of RAAA was higher in the open surgery group. We did not detect differences in postoperative mortality of RAAA according to the type of surgery. The risk factors for abdominal compartment syndrome were: perfusion >5 litres, coagulopathy, trans-fusion >6 units of packed red blood cells and metabolic acidosis. Primary decompressive laparotomy increased survival in the open surgery group, but not in the endovascular surgery group.
40
Nasim, Akhtar. "Evaluation of endovascular repair of abdominal aortic aneurysms." Thesis, University of Leicester, 1997. http://hdl.handle.net/2381/29600.
Повний текст джерелаАнотація:
Initially a retrospective study was undertaken to assess the current abdominal aortic aneurysm practice in terms of workload, mortality, complications and risk factors, to assess whether there is a role for endovascular AAA repair in Leicester. Then an experimental animal model was developed to investigate the necessity for anchoring the distal end of the graft with a second stent, the effect of placing stents across the renal ostia, and whether inferior mesenteric or lumbar artery backbleeding persists into the excluded aneurysm sac. A study has also been performed to assess the clinical application of this technique. A prospective study was undertaken in 82 consecutive patients referred for elective aneurysm repair to determine the best imaging modality for pre-operative assessment prior to endovascular AAA repair. A comparison was made between computed tomography (CT), magnetic resonance angiography (MRA), colour duplex and intra-arterial digital substraction angiography (IA-DSA). The morphology of the aneurysm in these patients was assessed to determine the proportion of patients that may benefit from this technique. Finally, the preliminary clinical experience with 3 different endoluminal grafts, one of which was developed in this study, was assessed. The results presented in this thesis show that work load of AAAs in Leicester has slowly increased over the past decade but there has been no significant improvement in the mortality figures for elective and emergency aneurysm surgery during this period. The results of the animal work show that a distal stent is necessary for complete exclusion of the aneurysm sac, but the safety of deploying stents across the renal arteries remains uncertain. This study also shows that MRA provides the best non-invasive assessment of aneurysm morphology prior to endovascular repair when compared to CT and IA-DA (p < 0.01).
41
Maiellaro, Kathryn Adele. "The role of oxidative stress in abdominal aortic aneurysm development: molecular and mechanical effects in the origins of aneurysmal disease." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24708.
Повний текст джерелаАнотація:
Thesis (M.S.)--Biomedical Engineering, Georgia Institute of Technology, 2009.Committee Chair: W. Robert Taylor; Committee Member: John Oshinski; Committee Member: Kathy Griendling; Committee Member: Raymond P. Vito; Committee Member: Rudolph L. Gleason.
42
Sun, Zhonghua. "CT virtual intravascular endoscopy in aortic stent grafting." Thesis, University of Ulster, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248607.
Повний текст джерела
43
Queiroz, Andre Brito. "Análise biomecânica e histológica do colo do aneurisma da aorta abdominal infrarrenal: estudo em necrópsia." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-22012016-083039/.
Повний текст джерелаАнотація:
INTRODUÇÃO: O colo dos aneurismas da aorta abdominal infrarrenal é o principal local de interação entre a parede aórtica e as próteses utilizadas no seu tratamento, pela técnica aberta ou endovascular. A dilatação do colo no acompanhamento pósoperatório, levando a falhas no tratamento, demonstra a importância de um colo confiável para um reparo eficiente em longo prazo. OBJETIVOS: Determinar as propriedades biomecânicas e histológicas do colo do aneurisma da aorta abdominal infrarrenal, comparando os resultados com as propriedades da aorta suprarrenal e da parede anterior do aneurisma. MÉTODOS: Dezesseis aneurismas da aorta abdominal infrarrenal encontrados em necrópsia foram removidos e dissecados em laboratório. A anatomia original dos aneurismas foi restabelecida com o auxílio de um balão complacente inserido na luz dos espécimes, sendo que aneurismas com um colo mais curto que 10 mm foram excluídos. Fragmentos transversais similares da parede anterior do aneurisma, do colo e da aorta suprarrenal foram obtidos com o auxílio de um dispositivo de corte apropriado. Testes de tração uniaxiais destrutivos foram realizados para a obtenção das seguintes propriedades biomecânicas: tensão, estresse, energia de deformação e deformação no momento da falência, além da medida da espessura dos fragmentos. A análise histológica destes fragmentos consistiu na quantificação das fibras colágenas, elásticas e espessura da camada média. RESULTADOS: Em doze aneurismas rotos e quatro não rotos, a análise biomecânica dos fragmentos de tecido arterial não demonstrou diferenças estatisticamente significativas entre os valores médios das propriedades biomecânicas de falência (tensão, estresse, energia de deformação e deformação), assim como para a espessura nos três segmentos estudados. O percentual de colágeno para o colo foi significativamente menor que na parede dos aneurismas (p = 0,010) e não foi significativamente diferente da aorta suprarrenal (p = 0,155). A elastina apresentou percentual significativamente maior no colo (p < 0,001) e na aorta suprarrenal (p < 0,001) quando comparados aos aneurismas. Não houve diferença na quantificação da elastina entre o colo e o segmento suprarrenal (p = 0,457). A espessura da camada média não apresentou diferença estatística relevante entre as três regiões avaliadas (p = 0,660). CONCLUSÕES: Os resultados biomecânicos sugerem que o aneurisma da aorta infrarrenal, ao invés de uma processo localizado, seja resultado de um acometimento aórtico difuso. Tanto a resistência quanto a elasticidade do segmento aneurismático apresentam semelhanças quando comparados aos segmentos aórticos não dilatados. Na análise histológica, nota-se preservação da elastina nos segmentos aórticos não dilatados, enquanto há redução na parede aneurismática; além de maior deposição de colágeno nesta regiãoINTRODUCTION: The neck of the infrarenal abdominal aortic aneurysm is the principal site of interaction between the aortic wall and the devices used in the repair of these aneurysms, by open or endovascular technique. Postoperative aneurysm neck dilation leading to aneurysm exclusion failures demonstrates the importance of a reliable neck for the long-term efficient repair. OBJECTIVE: To access the biomechanical and histological properties of the infrarenal aortic aneurysm neck, comparing the results with the properties of the suprarenal aorta and the anterior wall of the aneurysm. METHODS: Sixteen infrarenal abdominal aortic aneurysms found in necropsies were removed and dissected in laboratory. The original anatomy of the aneurysms was restored with the aid of a compliant balloon inserted in the specimens lumen and aneurysms with a neck shorter than 10 mm were excluded. Similar transverse fragments from the anterior aneurysm wall, aneurysm neck, and suprarenal aorta were obtained with the aid of a cutting device. Uniaxial destructive tensile tests were performed to obtain the following biomechanical properties: tension, stress, strain energy and strain at the moment of fragment failure, and the thickness of the fragments. Histological analysis was performed with the quantification of collagen and elastin, and middle layer thickness in these three fragments. RESULTS: In twelve ruptured and four unruptured aneurysms, the biomechanical analysis of the fragments showed no statiscally signicant differences between the mean values of the biomechanical properties (tension, stress, strain energy and strain), as well as the thickness of the fragments in the three groups. The percentage of collagen in the neck was significantly lower than in the aneurysm wall (p = 0,010) and was not significantly different from the suprarenal aorta (p = 0,155). Higher percentage of elastin was present in the neck (p < 0,001) and in the suprarenal aorta (p < 0,001) when compared to aneurysms. There was no difference in the quantification of elastin between the neck and the suprarenal segment (p = 0,457). The middle layer thickness showed no significant statistical difference between the three evaluated regions (p = 0,660). CONCLUSIONS: Biomechanical results suggest that the infrarenal aortic aneurysm, rather than a localized process, is a result of diffuse aortic involvement. Both the resistance and elasticity of the aneurysmal segment have similarities when compared to non-dilated aortic segments. In the histological analysis, there is preservation of elastin in non-dilated aortic segments, while there is a reduction in the aneurysmal wall; and there is greater collagen deposition in the aneurysmatic region
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Haug, Erik Skaaheim. "Infrarenal abdominal aortic aneurysm : comorbidity and results following open surgery." Doctoral thesis, Norwegian University of Science and Technology, Department of Circulation and Medical Imaging, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1772.
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Hadjianastassiou, Vassilis Georgiou. "Risk stratification modelling in post-operative abdominal aortic aneurysm patients." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491903.
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Introduction: the aim of the project was to test the hypothesis that 'the principles of risk stratification modelling can be successfully applied in a combined group of both elective and emergency AAA patients in the immediate post-operative setting'. Methods: the applicability of two existing generic risk stratification models as predictors of in-hospital mortality was assessed in a combined group of elective and emergency post-operative abdominal aortic aneurysm patients, from 24 Intensive Care Units in the North-Thames. The better of the two models was chosen to develop a disease-specific risk stratification model (the APACHE-AAA) in this group of patients, using hierarchical logistic regression. The accuracy of this new model was compared to that of artificial neural networks and clinician predictions on the same patient population. The APACHE-AAA model was then externally validated in a patient population (from the Oxford/Lewisham Intensive Care Units) independent from the one used to develop it and the model's prognostic accuracy was also compared with existing risk stratification models (POSSUM or VBHOM based) advocated for use in abdominal aortic aneurysm patients. Results: The two generic risk stratification models did not predict outcome accurately when applied to the North-Thames population of patients. The disease-specific APACHE-AAA model subsequently developed, successfully predicted outcome in this patient population, as evidenced by all measures of internal validity such as callibration and discrimination properties and subgroup analyses. The APACHE-AAA and the corresponding artificial neural network models were found to be more accurate than Intensive Care resident doctors in quantifying prognosis. The artificial neural network model had inferior calibration properties to the logistic regression model. The APACHE-AAA model was successfully externally validated in the Oxford/Lewisham patient population. Existing POSSUM- and VBHOM-based risk stratification models did not model outcome accurately in this population. Conclusions: the principles of risk stratification modelling were successfully applied in post-operative abdominal aortic aneurysm patients. The APACHE-AAA model exemplifies the methodology required to formulate a national reference system for reliable assessments of the quality of intensive care, for evaluative research and in prognostication in this group of patients.
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Qu, Zao, and 瞿早. "Expression of sphingosine-1-phosphate receptor in abdominal aortic aneurysm." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47050834.
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Ang, Lisa Shouning. "The extracellular role of granzyme B in abdominal aortic aneurysm." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45649.
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Liu, Jing. "THE ROLE OF APOB-CONTAINING LIPOPROTEINS IN ABDOMINAL AORTIC ANEURYSM." UKnowledge, 2015. http://uknowledge.uky.edu/pharmacol_etds/12.
Повний текст джерелаАнотація:
Abdominal aortic aneurysm (AAA) is a devastating disease that exhibits permanent lumen expansion typically in the infrarenal aorta. AAA is prevalent among aged population, especially in males. Despite the incidence in women is lower, studies indicate the tortuosity is more severe and aortic rupture risk is higher in women. In most patients, AAA remains asymptomatic until it ruptures leading to sudden and fatal hemorrhage.
To date, there is no proven medical therapy that can prevent the expansion or rupture. Human observational studies implicate the presence of AAA is associated with both high plasma low-density lipoprotein-cholesterol (HDL-C) and low plasma high-density lipoprotein-cholesterol (HDL-C) concentrations. To examine the role of specific lipoproteins in development of AAA, angiotensin (Ang) II-induced AAA was firstly determined in apolipoprotein AI deficient (apoAI -/-) mice in both C57BL/6 and LDL receptor deficient (LDL receptor -/-) backgrounds. The deletion of apoAI led to a significant decrease of HDL-C concentrations. However, we were unable to define any exacerbation of AngII-induced AAA in either normo- or hyperlipidemic mice with apoAI deficiency. Next we compared AngII-induced AAA formation using multiple mouse strains with dietary manipulation to generate different severities of hypercholesterolemia. We demonstrated the apolipoprotein B (apoB)-containing lipoproteins promoted the development of AngII-induced AAA. Moreover, ezetimibe administration significantly reduced both apoB-containing lipoproteins and AAA formation. Together, our studies demonstrate that elevated apoB-containing lipoproteins, contribute to the development of AngII-induced AAA.
To investigate the role of apoB-containing lipoproteins on established AAA, male LDL receptors -/- mice fed a Western diet were infused with AngII for 4 weeks to induced AAA. Then mice with AAA were stratified into either a group maintained on western diet or switched to a normal diet. AngII infusion was continued for an additional 8 weeks. The diet switch resulted in significantly reduced plasma cholesterol concentrations, which was attributable to the decrease of apoB-containing lipoproteins. We found a profound inhibition of aneurysm progression in diet switched mice associated with attenuated macrophage accumulation and medial thickening. Collectively, our data demonstrate that apoB-containing lipoproteins promote the progression of established AAA.
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O'Connell, Mary Kathleen. "Understanding abdominal aortic aneurysm progression through three-dimensional microstructure imaging /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Troxler, M., Khalid M. Naseem, and Shervanthi Homer-Vanniasinkam. "Increased nitrotyrosine production in patients undergoing abdominal aortic aneurysm repair." Wiley, 2004. http://hdl.handle.net/10454/4094.
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noVascular inflammation is implicated in the pathogenesis of atherosclerosis and abdominal aortic aneurysm (AAA), and is thought to involve reactive species such as the nitric oxide-derived oxidant peroxynitrite. In the present study nitrotyrosine was measured as a stable marker of peroxynitrite production in vivo. Perioperative blood samples were obtained from patients undergoing elective open or endovascular repair of an AAA and from patients with intermittent claudication, smoking aged-matched controls, non-smoking aged-matched controls and non-smoking young healthy controls. Plasma nitrotyrosine was measured by an enzyme-linked immunosorbent assay. The median plasma nitrotyrosine concentration in patients with an AAA (0·46 nmol nitrated bovine serum albumin equivalents per mg protein) was significantly higher than that in patients with intermittent claudication (0·35 nmol; P = 0·002), smoking controls (0·36 nmol; P = 0·001), non-smoking controls (0·35 nmol; P = 0·002) and young healthy controls (0·27 nmol; P < 0·001). Nitrotyrosine concentrations increased during early reperfusion in open AAA repair, but not during endovascular repair. AAA exclusion from the circulation reduced levels to control values (P = 0·001). Patients with an AAA had raised levels of circulating nitrated proteins compared with patients with claudication and controls, suggesting a greater degree of ongoing inflammation that was not related to smoking. Copyright