Orientador: Hamilton Almeida Rollo / Resumo: 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

Made available in DSpace on 2014-06-11T19:27:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-25Bitstream added on 2014-06-13T20:36:03Z : No. of bitstreams: 1 shiraishi_fg_me_botfm.pdf: 1396975 bytes, checksum: ae8938a765c04aaf60bdc962bdb062da (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Pacientes com doença renal crônica usualmente apresentam intolerância ao exercício e aumento de rigidez arterial. O objetivo desse estudo foi avaliar a associação entre o condicionamento físico e a pressão arterial central, espessura da camada íntima-média de carótida e rigidez arterial em pacientes com doença renal crônica, além de analisar a interação desses fatores com as variáveis clínicas e laboratoriais. Foi avaliada a pressão arterial central, velocidade de onda de pulso e índice de amplificação de 22 pacientes utilizando o aparelho Sphygmocor. Também foi determinada a espessura da camada íntima-média de carótida por meio da ultrasonografia. O condicionamento físico foi avaliado pela medida do VO2 máximo, estimado por ergometria utilizando o protocolo de Bruce. De acordo com o VO2 máximo, 2 grupos de pacientes foram obtidos. Grupo I (GI) com valores abaixo da mediana e Grupo II (GII) com valores acima. O GI apresentou diferenças estatísticas com relação à velocidade da onde de pulso e do índice de amplificação, configurando maior rigidez arterial. Os valores de massa gorda, proteína C-reativa, hemoglobina e albumina foram estatisticamente diferentes entre os grupos. A massa gorda e proteína C-reativa foram maiores no GI do que no GII. A hemoglobina e albumina, ao contrário, foram maiores no GII do que no GI. A espessura da camada íntima-média de carótida e a pressão arterial central foram similares entre os grupos. Melhor condicionamento físico foi associado com menor rigidez arterial em pacientes com doença renal crônica / Chronic kidney disease patients usually presents exercise intolerance and increased arterial stiffness. The aim of this study was to evaluate the association between physical fitness and the degree of arterial stiffness in chronic kidney disease patients, as well to analyze its relation with clinical variables. Twenty-two patients were evaluated by central blood pressure, pulse wave velocity and augmentation index using Sphygmocor device. Carotid intima-media wall thickness was assessed by ultrasonography and fitness performance estimated by VO2 max using Bruce protocol treadmill test. Patients were distributed in two groups according to the median value obtained for VO2 max: Group 1 (GI) with VO2 max below the median and Group 2 (GII) with values above the median. The GI presented significant increase of pulse wave velocity and augmentation index configuring higher arterial stiffness for this group. Other clinical variables as fat mass, C-reactive protein, were higher in GI and hemoglobin and albumin, on the contrary, were higher in GII Carotid intima-media wall thickness and central blood pressure were similar in both groups. Better fitness was associated with lower arterial stiffness in CKD patients

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We report our experience with asymptomatic valvar aortic stenosis diagnosed during infancy. During the period between November 1, 1986 and October 31, 1992 a total of 13 infants were diagnosed with asymptomatic aortic stenosis, 5 of whom showed rapid progression over the first 2 years of life. Two of these asymptomatic infants had severe aortic stenosis by 2 months of age, requiring intervention. We agree that aortic stenosis is a progressive lesion even in mild cases, but we emphasize the need for close clinical and echocardiographic follow-up of these asymptomatic children during infancy to prevent congestive heart failure and sudden death.

<p> A stress analysis of porcine aortic valve leaflets in diastole at 80 mm. Hg. in-vitro is presented. Incorporations of local surface geometry, leaflet material inhomogeneity, anisotropy and non-linearity are applied. The stress theory used is a modified form of the thin membrane stress theory for a homogeneous, linearly elastic and orthotropic lamina. Modifications are made so that the linear Hooke's Law equations of stress may be applied to the inhomogeneous, non-linearly elastic and orthotropic thin membrane aortic valve leaflets. </p> <p> Stress calculations are made on the premise that the diastolic valve leaflets at 80 mm. Hg. are in pre-transition (that is, characterized by a small elastic modulus) for the circumferential direction, and in post-transition (that is, characterized by a large elastic modulus) for the radial direction. Circumferential stresses are calculated to be relatively negligible; they are estimated to be less than 1 gm/mm². Radial stresses for the non coronary leaflet lie primarily in the 0 to 20 gm/mm² range. The regions of the largest stress concentrations are in the areas of mutual leaflet coaptation, especially near the Nodes of Aranti. A progressive increase of the radial stresses from the sinus annulus edges toward the coaptation edges of the leaflets is also observed. Based on the one valve reported , it appears that the left coronary leaflet is the highest stressed and the right coronary leaflet is the least stressed. Central leaflet radial stresses for the right coronary leaflet are in the 0 to 10 gm/mm² range, as compared to 0 to 20 gm/mm² for the non coronary and left coronary leaflets. </p> <p> The question as to whether the diastolic strains of the valve leaflets are in pre-transition, transition or post-transition is raised. The resolution of the question is seen to be critical to the validity of the stress analysis. It is also realized that further improvements in the analysis are possible through improvements and refinements to the experimental methods used in obtaining the necessary inputs for the analysis. </p> / Thesis / Master of Engineering (ME)

Aortic valve replacement (AVR) is the only life-saving treatment for patients with severe symptomatic aortic stenosis. Bioprosthetic valves are used in 90% of AVRs because they do not require lifelong anticoagulation. The major limitation of bioprosthetic valves is their limited durability compared to mechanical valves. In addition, bioprosthetic valves still carry a 2-3% risk of symptomatic valve thrombosis, stroke, and thromboembolism in the first 30 days after implantation, and a 1% annual risk thereafter. The risk of subclinical valve thrombosis is around 10% at 30 days and 25% at 1 year, and prevention of subclinical valve thrombosis is hypothesized to reduce the risk of clinical thrombotic events and perhaps even improve valve durability, although high-quality evidence is lacking. This doctoral thesis comprises 7 chapters of varied methodology that summarize the evidence behind current recommendations for antithrombotic therapy after bioprosthetic AVR, identify evidence gaps, and present the design a randomized trial that aims to address some of these evidence gaps. Chapter 1 introduces each included study with a brief summary. Chapter 2 is a narrative review summarizing guideline recommendation for antithrombotic therapy after bioprosthetic AVR and the evidence upon which they are based. Chapter 3 is an observational study describing antithrombotic prescribing practices in the VISION Cardiac Surgery cohort study. Chapter 4 is a systematic review and network meta-analysis of randomized studies of antithrombotic therapy after transcatheter aortic valve replacement. Chapter 5 is a systematic review and meta-analysis of randomized and observational studies of subclinical valve thrombosis. Chapter 6 presents the design and rationale of a feasibility trial of direct oral anticoagulants versus vitamin K antagonists in patients with a new surgical bioprosthetic AVR and atrial fibrillation. Chapter 7 discusses the implications, limitations, and future avenues of the research presented in this doctoral thesis. / Thesis / Doctor of Philosophy (PhD) / More than 10,000 Canadians require aortic valve replacement each year. Bioprosthetic valves (made out of cow or pig tissue) are often preferred over mechanical valves (made out of metal) because the risk of blood clots forming on the valve or causing a stroke is lower. The disadvantage of bioprosthetic valves is that they can wear out and require re-replacement. The reason why bioprosthetic valves wear out is uncertain, but it may be related to small blood clots on the valve that are only detectable on a CT scan. This doctoral thesis explores the use of blood thinners for patients with bioprosthetic aortic valve replacement. Ideally, blood thinners would be able to prevent blood clots and stroke, and to improve the durability of bioprosthetic valves, without causing too much bleeding. The thesis reviews the available evidence, identifies unanswered questions, and ends with a proposal for a study to generate new data.

No description available.

No description available.

Aortic Stenosis (AS) is the most common valvular heart disease. Aortic valve replacement (AVR) is the only acceptable treatment for AS. Several replacement methods are available to treat AS including conventional surgical aortic valve replacement (SAVR), transcatheter aortic valve replacement (TAVR), and Sutureless aortic valve replacement (SuAVR). SAVR showed excellent long-term results. However, it is an invasive procedure and is denied in substantial number of patients. TAVR showed excellent results and outcomes when compared to SAVR. However, it is associated with increased rate of paravalvular leaks that may impact long term outcomes. SuAVR has developed to overcome the drawbacks of SAVR and TAVR. SuAVR is associated with favorable short and midterm outcomes when compared to SAVR and TAVR. In this thesis, we summarize the safety, the evidence and the perceptions of using SuAVR in Canada. In Chapter1, we evaluated the use of SuAVR Perceval bioprosthesis in retrospective single center study of 415 patients with AS. SuAVR showed excellent immediate post-operative and hemodynamics outcomes. In chapter 2, we sought to establish perceptions and patterns to SuAVR use among Canadian cardiac surgeons. Sixty-Six Canadian cardiac Surgeons responded to the survey. Surgeons reported influential factors, barriers to use SuAVR, and their interest in a trial comparing SuAVR versus TAVR. Surgeons were likely to use SuAVR in high risk patients with hostile aortic root, small aortic annulus and in patients undergoing concomitant procedures whereas cost was the main limiting factor to use SuAVR in Canada. Majority of surgeons reported their interest in participating in a trial comparing SuAVR with TAVR. In chapter 3, we systematically reviewed and meta-analyzed the international evidence of using SuAVR versus SAVR and TAVR. SuAVR showed favorable or comparable results to SAVR and TAVR. However, long term and randomized data are needed to confirm these results. / Thesis / Master of Science (MSc) / Aortic valve stenosis (AS) is considered the most common valvular heart disease, which caused by narrowing of the aortic valve. Aortic valve replacement (AVR) is the only acceptable treatment to relieve the stenosis. Several strategies are available including conventional surgical aortic valve replacement (SAVR), transcatheter aortic valve replacement (TAVR), and sutureless aortic valve replacement (SuAVR). SAVR is an invasive procedure and denied in a considerable number of patients with aortic stenosis due to aging and presence of multiple diseases leading to higher risk of complications. TAVR is less invasive option and showed excellent results when compared to SAVR. However, it was associated with complications. SuAVR has developed to overcome some of the drawbacks of SAVR and TAVR. SuAVR is associated with short operation time and less complications compared to SAVR and TAVR. This thesis summarizes the safety, perceptions and evidence surrounding the use of SuAVR.

No / Vascular 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