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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Angioplastia transluminal percutânea: contribuição ao tratamento da hipertensão arterial renovascular e da nefropatia isquêmica / Percutaneous transluminal angioplasty: contribution to the treatment of renovascular hypertension and nephropathy ischemic

Martins, Valéria Marcia 22 March 2004 (has links)
As lesões estenóticas ou oclusivas das artérias renais podem levar à isquemia do parênquima renal com conseqüente hipertensão arterial (hipertensão arterial renovascular) e perda de função renal (nefropatia isquêmica). Estas duas entidades podem ser tratadas por medicamentos, cirurgia ou angioplastia transluminal percutânea. O objetivo deste trabalho foi avaliar o sucesso técnico e funcional da angioplastia em lesões estenóticas ou oclusivas das artérias renais em doentes portadores de hipertensão arterial renovascular e nefropatia isquêmica. Tratamos 131 doentes hipertensos com ou sem alteração da função renal (55 do sexo masculino e 76 feminino), que apresentavam 191 artérias renais comprometidas (148 estenoses e 43 oclusões) e com média de idade de 45,83 ± 17,4 anos (4 a 77 anos). A etiologia da lesão da artéria renal foi a aterosclerose em 65 doentes (49,61%), displasia fibromuscular em 41 (31,29%), arterite de Takayasu em 13 (9,92%) e outras causas em 12 (9,16%). O nível sérico de creatinina era normal em 70 (53,43%) e alterado em 61 (46,58%). O sucesso técnico foi obtido em 93 doentes (70,99%) e em 123 artérias renais (75,46%). O seguimento foi, em média, de quatro anos (2 a 8 anos), sendo que ao final deste período houve redução de 37,80 ± 33,46 mmHg e 28,66 ± 24,74 mmHg nos níveis da PA sistólica e diastólica, respectivamente. Houve cura da hipertensão arterial em nove doentes (11,25%), melhora em 59 (73,75%), permaneceu inalterada em oito (10%) e piorou em quatro (5%). A função renal ficou normal em 36 doentes (45%), melhorou em 11 (13,75%), manteve-se em 26 (32,5%) e piorou em sete (8,75%). Houve recidiva em 14 casos (17,5%), sendo 11 casos (78,57%) tratados com sucesso com nova angioplastia. Conclusão: consideramos que a angioplastia transluminal percutânea pode ser indicada como opção para o tratamento das lesões estenóticas e/ou oclusivas das artérias renais nos doentes com hipertensão renovascular e nefropatia isquêmica / The occlusive and stenotic lesions of the renal arteries can lead to a renal parenchyma ischemia with vascular hypertension resultant (reno vascular hypertension) and loss of renal function (nephropathy ischemic). These two conditions can be treated by medications, surgery or Percutaneous Transluminal Angioplasty (PTA). The objective of this work was assessing the technical and functional success of PTA in stenotic or occlusive lesions of renal arteries in patients having renovascular hypertension and nephropathy ischemic. We treated 131 hypertensive ill people with or without alteration in the renal function (55 males and 76 females) who presented 191 damaged renal arteries (148 stenosis and 43 occlusions) and age range of 45.83+ 17.4 years old (4 to 77 years old). The etiology of the lesion in the renal artery was atherosclerosis in 65 ill people (49.61%), fibro muscular dysplasia in 41 (31.29%), Takayasu\'s disease in 13 (9.92%), and other causes in 12 (9.16%). The plasma creatinine level was normal in 70 (53.43%) and altered in 61 (46.58%). The technical success was obtained in 93 ill people (70.99%) and in 123 renal arteries (75.46%). The follow-up lasted in average for 4 years (2 to 8 years), in which the end of the period there was a decrease of 37.80+33.46 mmHg and 28.66+24.74 mmHg in the systolic and diastolic blood pressure levels respectively. There was a cure of artery hypertension in 9 ill people (11.25%), better results in 59 (73.75%), no alteration in 8 (10%) and worsening in 4 (5%). The plasma creatinine level increased in 10% (SD), although the renal function remained normal in 36 ill people (45%), better in 11 (13.75%), remained the same in 26 (32.5%) and got worse in 7 (8.75%). There was a reoccurrence in 14 cases (17.5%), in which 11 cases (78.57%) were treated successfully with new PTA. Conclusion: it was considered that PTA can be indicated as an option for the treatment of stenotic and occlusive lesions of the renal arteries in ill people with renovascular hypertension and nephropathy ischemic
32

Development of catheter techniques to treat native and acquired stenoses in congenital heart disease

Magee, Alan Gordon January 2016 (has links)
Aim: To describe innovative uses of catheter based treatment in a variety of native and post surgical stenoses in children and young adults with congenital heart disease. Background: Cardiac catheterization in man was first described 1929 and since then there has been a drive to develop endovascular techniques to investigate and treat both congenital and acquired heart disease. Many of the advances are being made in congenital heart disease. Methods: A number of congenital cardiac stenotic lesions were studied including baffle obstruction after atrial switch for transposition of the great arteries, aortic stenosis in infants, coarctation of the aorta, peripheral pulmonary artery stenosis and superior vena caval obstruction. The use of angioplasty balloons, cutting balloons, stents and alternative catheter approaches were investigated for these lesions. Results: Following atrial redirection surgery for transposition of the great arteries balloon angioplasty improved baffle haemodynamics. The technique of anterograde balloon dilation of the aortic valve was developed and had superior outcomes in terms of aortic insufficiency compared to a retrograde approach in neonates with severe aortic valve stenosis. In an animal model of peripheral pulmonary arterial stenosis, the application of cutting balloon angioplasty produced effective relief in a controlled fashion. Balloon mounted stents were used in patients with native and post surgical coarctation of the aorta with significant relief of stenosis and relief of hypertension. Finally, a group of patients with superior vena obstruction syndrome after surgical repair of partial anomalous pulmonary venous drainage had successful treatment using balloon mounted stents. Conclusions: Catheter based treatment of congenital and post surgical vascular stenoses of the heart and great arteries using angioplasty balloons, cutting balloons and balloon mounted stents is safe and appears to be effective in the short and medium term. It may represent a useful alternative to surgery and will reduce the number of surgical procedures required over a lifetime. Future directions will include bio-absorbable stents and hybrid techniques involving surgery.
33

Caracterização do perfil dos componentes do sistema das cininas, óxido nítrico e metaloproteinases como marcadores na reestenose precoce de stents revestidos pós angioplastia transluminal percutânea periférica / Characterization of the profile of kinins system, nitric oxide and metalloproteinases as markers in coated stent early restenosis post peripheral percutaneous transluminal angioplasty

Rocha, Laura de Andrade da 04 December 2015 (has links)
Introdução: A reestenose pós tratamento endovascular de lesões ateroscleróticas em artérias periféricas é a principal desvantagem desta técnica minimamente invasiva. A inflamação vascular após angioplastia com balão e/ou implante de stent desempenha um papel importante na proliferação de células do músculo liso vascular e posterior crescimento de uma neoíntima, e vários marcadores inflamatórios têm sido referidos como potenciais preditores dessa complicação, porém os fatores que contribuem para a estenose intra-stent no segmento vascular periférico não foram completamente elucidados. Recentemente, tem-se sugerido que a superfície revestida de stents recobertos possa impedir a reestenose de forma mais eficaz do que os stents convencionais. Objetivo: Avaliar o papel do sistema calicreína-cinina (SCC), do óxido nítrico (NO) e das metaloproteinases (MMP), mediadores inflamatórios importantes e que contribuem ativamente para a reparação de tecidos, no processo de reestenose arterial devido a hiperplasia intimal, pós angioplastia com stent recoberto no segmento fêmoro-poplíteo, com a intenção de contribuir com novas medidas terapêuticas. Método: Foi realizado um estudo prospectivo envolvendo 27 pacientes submetidos à angioplastia com stent revestido no segmento fêmoro-poplíteo, selecionados no Ambulatório de Cirurgia Vascular e Endovascular do HCFMRP/USP. Foram estudados os seguintes marcadores: sistema calicreína-cininas - com quantificação dos substratos (cininogênio de alto e baixo peso molecular - CAPM / CBPM) e da atividade das enzimas (calicreína plasmática e tecidual e cininase II); a determinação dos níveis de nitrito e nitratos para a avaliação de óxido nítrico; dosagem das MMPs 2 e 9 e dos níveis circulantes de seus inibidores (inibidores teciduais das metaloproteinases - TIMPs [1 e 2]). Amostras de sangue foram coletadas antes do implante do stent, 24 horas e seis meses após o procedimento. Foi realizado ultrasson Doppler após seis meses, e, na presença de alterações, realizada angiografia para comprovação da presença de reestenose. Resultados: Quatro (14,8%) dos vinte sete pacientes estudados desenvolveram reestenose (>= 50%) em seis meses. Esses pacientes tiveram níveis significativamente mais baixos de CAPM (24h, P <0,05) e de CBPM (antes - P <0,05; 24 horas P <0,01; 6 meses P <0,05); níveis mais baixos de TIMP 2 ( seis meses P<0,05) comparados ao grupo sem reestenose. As atividades da calicreína plasmática e tecidual, da cininase II, NO e MMPs tiveram comportamento semelhante entre os pacientes com e sem reestenose. Conclusão: As taxas de reestenose foram baixas com o uso de stents revestidos no segmento fêmoro-poplíteo comparativamente aos índices publicados de stents não revestidos. Os pacientes que desenvolveram reestenose mostraram níveis reduzidos de cininogênios e de TIMP-2 (seis meses após a angioplastia). Por outro lado, não foi possível demonstrar a participação do óxido nítrico e das metaloproteinases no processo de reestenose / Background: Restenosis after endovascular treatment of atherosclerotic lesions in the peripheral circulation is the major drawback of this minimally invasive technique. Vascular inflammation after balloon angioplasty or stent implantation plays an important role in smooth muscle cells proliferation and subsequent neointima growth, and various inflammatory markers have been reported as potential predictors of this complication, but the factors that contribute to the in-stent stenosis in peripheral vascular segment have not been fully elucidated. Recently, it has been suggested that the coated surface of stents grafts can prevent restenosis more effectively than conventional stents. Objective: The aim of this study was to evaluate the role of the kallikrein-kinin system (KKS), nitric oxide (NO) and metalloproteinases (MMPs), wich are important inflammatory mediators and actively contribute to tissue repair, in the process of arterial restenosis due to intimal hyperplasia, with the aim of developing new interventions. Method: Single-center prospective study with 27 patients with peripheral artery disease (PAD) requiring percutaneous transluminal angioplasty (PTA) and stenting, in the femoropopliteal segment, using coated stents grafts, was performed. The following markers were studied: kallikreinkinin system using the quantification of proteins (high and low weight Molecular kininogen HMWK / LMWK), verification of enzyme activity (tissue kallikrein, plasma kallikrein and kininase II), determination of nitrite and nitrates levels for evaluation of nitric oxide, MMPs 2 and 9 circulating levels and their inhibitors (tissue inhibitors of metalloproteinases [TIMPs 1 and 2]). Serum samples were collected before stent implantation, 24 h and six months after the procedure. Doppler ultrasound was performed after six months, and in the presence of any changes, an angiography was performed to prove the presence of restenosis. Results: Four (14,8%) of the treated patients developed restenosis (>50%) within 6 months. These patients had significantly lower levels of HMWK (24 hours, P < .05), LMWK (before - P < .05; 24 hours - P < .01; 6 months - P < .05) and lower levels of TIMP 2 (6 months < .05) compered to no restenosis group. The activities of plasma and tissue kallikrein, kininase II, NO and MMP had similar behavior among patients with and without restenosis. Conclusion: Restenosis rates were low with the use of coated stents in the femoropopliteal segment compared to published bare metal stents results. Patients with restenosis showed reduced levels of kininogens and TIMP-2 (six months after angioplasty) in patients who developed restenosis. Moreover, it was not possible to demonstrate the involvement of nitric oxide and metalloproteinases in the restenosis process
34

Interventional cardiology: a portfolio of research pertaining to femoral sheath removal practices and patient education

Jones, Tina. January 2003 (has links) (PDF)
"March 2003" Includes bibliographical references (leaves 61-68). Appendices: Publications arising from the research portfolio. 1. Conducting a systematic review -- 2. The effectiveness of mechanical compression devices in attaining hemostasis after removal of a femoral sheath following femoral artery cannulation for cardiac interventional procedures : a systematic review -- 3. Effectiveness of mechanical compression devices in attaining hemostasis after femoral sheath removal Contains three separate research projects, presented as separate reports, but all related to one area of interest - interventional cardiology. Seeks to identify effective femoral sheath removal practices after interventional cardiac procedures and determine patient's perceptions of the education prior to and after interventional procedures.
35

Interventional cardiology: a portfolio of research pertaining to femoral sheath removal practices and patient education / Tina Jones.

Jones, Tina January 2003 (has links)
"March 2003" / Includes bibliographical references (leaves 61-68). / 1 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Contains three separate research projects, presented as separate reports, but all related to one area of interest - interventional cardiology. Seeks to identify effective femoral sheath removal practices after interventional cardiac procedures and determine patient's perceptions of the education prior to and after interventional procedures. / Thesis (D.Nurs.Sc.)--University of Adelaide, Dept. of Clinical Nursing, 2003
36

Percutaneous Renal Artery Revascularization in Patients with Atherosclerotic Renal Artery Stenosis and Chronic Kidney Disease

Dichtel, Laura Elisabeth 11 September 2009 (has links)
The impact of percutaneous renal artery angioplasty and stenting (PTRAS) for treatment of atherosclerotic renal artery stenosis (ARAS) is not fully understood, especially in patients with chronic kidney disease (CKD). We performed a retrospective cohort study of patients with significant ARAS and moderate to severe chronic kidney disease (estimated GFR 15-60 ml/min/1.73m2) who were treated medically or with PTRAS. The primary endpoint of this study was change in renal function over the first year after treatment. Secondary endpoints included hemodynamic outcomes, antihypertensive medication doses, end stage renal disease (ESRD), and death. We reviewed all patients with a diagnosis of significant ARAS and impaired GFR treated between 1997-2007 in the Veterans Affairs Connecticut Healthcare System (VACHS). A total of 118 patients met inclusion criteria (71 medical treatment, 47 PTRAS), with an average follow-up of 34 months. The students t-test was used to compare baseline characteristics, as well as renal and hemodynamic endpoints between the two treatment groups. The cohort had a mean age of 73 ± 9 years and average baseline GFR of 37.2 ± 14.9 ml/min/1.73m2. Demographic, clinical and laboratory characteristics at baseline were similar between the two groups, with the exception of higher diastolic blood pressure in the stent group at baseline (75 versus 70 mmHg, p=0.028). No statistically significant difference was found between the two treatment groups for any renal endpoints. After a steady decline in GFR in both the medical treatment and stent groups during the 12 months preceding diagnosis (-4.2 versus -4.0 ml/min/1.73m2, p=0.911), GFR stabilized in both groups over the year following diagnosis (decline in GFR of -1.6 versus -1.4 ml/min/1.73m2, p=0.938). Multivariate models did not reveal an association between treatment modality and percent change in GFR during follow-up. No difference was found in blood pressure outcomes at 12 months between the medical and stent groups. Antihypertensive therapy, measured in defined daily doses (DDDs), was significantly higher in the medical treatment group at 12 months (4.5 versus 3.5 DDDs, p=0.048), but lost significance thereafter. In addition, the number of deaths was significantly higher in the stented group on univariate analysis, although this did not remain significant on multivariable Cox analysis. No difference was found between treatment groups in the development of ESRD. These data suggest that, among patients with ARAS and CKD, medical therapy and renal artery stenting are comparable in stabilizing renal function.
37

Modeling and cycle-to-cycle control of the angioplasty balloon forming process

Chen, Yan, 1982- January 2008 (has links)
The development of a new angioplasty balloon is a time consuming process. This thesis aims at reducing the amount of time and materials spent on the experimental stage of the development of new angioplasty balloons. This can be achieved by building a nonlinear neural network model of the balloon forming process and implementing an off-line cycle-to-cycle controller. The controller can learn from the previous experiments and provide better input parameters for improving the quality of the next balloons formed in the process. It is shown in the experimental test results that the neural network model can provide accurate estimates of the process outputs. The neural network model combined with a cycle-to-cycle control strategy has the potential to replace the trial-and-error approach to balloon development that is commonly applied today.
38

Perkutane transluminale Angioplastie komplexer infrapoplitealer Gefässläsionen bei kritischer chronischer Extremitätenischämie: Restenoserate und klinische Ergebnisse

Winkler, Bert 04 August 2014 (has links) (PDF)
Perkutane transluminale Angioplastie komplexer infrapoplitealer Gefässläsionen bei kritischer chronischer Extremitätenischämie: Restenoserate und klinische Ergebnisse
39

Interventional cardiology: a portfolio of research pertaining to femoral sheath removal practices and patient education /

Jones, Tina. January 2003 (has links) (PDF)
Thesis (D.Nurs.Sc.)--University of Adelaide, Dept. of Clinical Nursing, 2003. / "March 2003" Includes bibliographical references (leaves 61-68).
40

Surgical treatment of left main coronary artery stenosis /

Jönsson, Anders, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 5 uppsatser.

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