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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.
61

Duration of Anticoagulant Therapy for Unprovoked Venous Thromboembolism

Khan, Faizan 17 October 2022 (has links)
Venous thromboembolism (VTE) is a chronic illness that affects nearly 10 million people every year worldwide. Anticoagulant therapy with direct oral anticoagulants is the mainstay of treatment for patients with VTE, and should be continued for at least 3-6 months. Thereafter, a decision should be made to discontinue anticoagulation or continue it indefinitely. This decision is most challenging for patients with a first unprovoked VTE because of uncertainty in estimates for the long-term benefits (e.g., reduction in recurrent VTE) and harms (e.g., increase in major bleeding) of extended anticoagulation, and the trade-offs between them. The overarching aim of this doctoral thesis was to address these key evidence gaps that are pertinent to making decisions regarding the duration of anticoagulation for patients with a first unprovoked VTE. The first three studies of this thesis synthesized contemporary and reliable estimates for the long-term risks and consequences of recurrent VTE and major bleeding, with and without extended anticoagulation (parameters that can influence the clinical and cost-effectiveness of discontinuing versus continuing anticoagulation indefinitely). Broadly, these systematic reviews and meta-analyses found that: 1) the long-term risks and consequences of major bleeding during extended anticoagulation are considerable, particularly with vitamin K antagonists as well as in older patients, patients using antiplatelet therapy, and in patients with kidney disease, a history of bleeding, or anemia; and 2) the long-term risks of recurrent VTE during extended anticoagulation and major bleeding after discontinuing anticoagulation are reassuringly low but not negligible. The fourth study incorporated the synthesized evidence to compare the lifetime clinical benefits, harms, and costs of discontinuing versus continuing anticoagulation indefinitely. This decision analytic modelling study showed that indefinite anticoagulation is unlikely to either result in a net clinical benefit or be cost-effective in all (i.e., unselected) patients with a first unprovoked VTE. Findings from this thesis can serve to impact clinical practice and health policy by informing patient prognosis to guide shared decision-making regarding the duration of treatment for unprovoked VTE, and informing future research to ultimately identify which patients should receive anticoagulation indefinitely in order to maximize health benefits for the available healthcare resources.
62

Petrology and Geochemistry of Quartz-Tourmaline Vein Alteration of a Granodiorite, Heyson Township, Red Lake, Ontario

Gignac, Wayne 04 1900 (has links)
<p> The Buffalo Mine, located in Heyson Township, Red Lake, consists of quartz-tourmaline veins in a grandiorite. An alteration halo, consisting of andesine feldspar, quartz, calcite, with minor tourmaline, zircon, and opaques, is seen surrounding the veins. Opaque minerals consists of pyrite and hematite. Possible Na - overgrowths of the Plagioclase are seen , as well as complete destruction of the mafic minerals. </p> <p> Geochemistry shows that the wall-rock alteration involves the breakdown of Si, Al, Fe, Mg, Na, and K . Si and Al remain fairly constant, while Na and Ca increase and Fe, Mg, and K decrease in abundance. There has been a sufficient input of CO2 to precipitate calcite, as well as Enough sulfur to form pyrite. </p> <p> The initial hydrothermal solutions were high temperature NaCl solutions, enriched in boron and containing some CO2 . The fluids were likely oxidizing and had a neutral pH. </p> / Thesis / Bachelor of Science (BSc)
63

MECHANISMS OF VENOUS THROMBUS STABILITY

Shaya, Shana January 2022 (has links)
Whether a patient presents with deep vein thrombosis (DVT) or pulmonary embolism (PE) varies based on clinical factors. Patients with factor V Leiden (FVL) typically present with DVT while cancer patients present with PE. The biological mechanisms that determine DVT stability in the progression of DVT to PE are not known. Thus, little is known about the mechanism of thrombus stability, the factors involved, or the effect of anticoagulants on embolization and PE burden. In order to answer these questions, we first need to (i) develop a mouse model to evaluate DVT stability and its relationship with PE burden when treated with anticoagulants, (ii) determine if anticoagulants, by inhibiting thrombin, require FXIII to decrease thrombus stability, (iii) determine the effects of attenuating fibrinolysis, using epsilon aminocaproic acid (ε-ACA or EACA), supplemental FXIII and α2-AP, on clot stability and (iv) utilize our model to explain the FVL paradox. For our thrombus stability model, the femoral vein of C57BL/6, FXIII deficient (FXIII-/-), FVL heterozygous, or FVL homozygous female mice was subjected to ferric chloride (FeCl3) injury to initiate a non-occlusive thrombus. Treatment with saline, dalteparin, dabigatran, EACA or FXIII was administered 12 minutes after thrombus formation. Intravital videomicroscopy recorded the thrombus sizes and embolic events leaving the thrombus for 2 hours. Lungs were harvested, sectioned and stained for the presence of PE. Total and large embolic events were highest after dabigatran treatment compared to saline or dalteparin in wild-type (WT) mice. Variations in amounts of embolic events were not attributed to variations in thrombus size since thrombus size was similar between the groups. The number of emboli per lung slice was higher in dabigatran-treated mice. Large embolic events correlated positively with the number of emboli per lung slice independent of treatment. Dabigatran treatment in FXIII-/- mice did not alter embolization patterns suggesting that FXIII is required for dabigatran to decrease thrombus stability. EACA increases thrombus size significantly and therefore would not be a feasible alternative to IVC filters, as it will increase DVT size. FXIII marginally increased thrombus size. Treatment with FXIII decreases total and large embolic events in saline-, dalteparin- or dabigatran-treated mice, similar to EACA-treated mice. The number of emboli per lung slice was reduced after treatment with FXIII and EACA compared to non-treated mice. PE burden was not significantly different between FXIII anticoagulated mice or EACA-treated mice. The large embolic events correlate positively with PE burden. FVL heterozygous and homozygous mice had significantly reduced embolization and thrombus size grew significantly over time, this contrasted with WT mice, where thrombus size remained similar to the initial injury. PE burden was significantly reduced in the FVL mice compared to WT. Collectively, these data shows that we have successfully developed a mouse model of acute venous thrombus stability that can quantify emboli and PE burden. Consistent with clinical data, dabigatran, a DTI, was shown to acutely decrease thrombus stability and increase PE burden compared to LMWH or saline; an effect that was FXIII-dependent. Also, attenuating fibrinolysis with EACA, but not FXIII, increases thrombus size; but both increase DVT stability and decrease PE burden. Supplementing α2-AP did not alter thrombus stability. This suggests that administration of FXIII may be a better treatment option for DVT patients who are bleeding than EACA, since EACA may increase DVT size. Lastly, our model can explain the FVL paradox. Those with FVL have stable thrombus formation leading to an increased incidence of symptomatic DVT and a decreased risk of PE. / Thesis / Doctor of Philosophy (PhD)
64

Modelagem da poluição atmosférica em São Paulo utilizando inventários de emissões veiculares bottom-up / Air pollution modeling in São Paulo using bottom-up vehicular emissions inventories

Espinosa, Sergio Alejandro Ibarra 27 October 2017 (has links)
Neste trabalho, investiga-se o impacto de diferentes cenários de inventários de emissões veiculares na qualidade do ar nas regiões metropolitanas de São Paulo, Baixada Santista, Vale do Paraíba, Sorocaba e Campinas. A construção de inventários de emissões veiculares bottom-up é complexa, tendo que agregar informações diversas, como a composição da frota veicular (com a distribuição de idade, tipos de veículos, tipos de combustível) e os processos emissores (fatores de emissão para partidas a frio, emissões de escapamento e evaporativas). Além disso, para modelos de qualidade do ar, estas emissões ainda devem ser distribuídas no tempo e no espaço. Os cenários foram construidos utilizando diferentes fontes de dados, destacando-se as simulações de tráfego e contagem de veículos da CET e SPTRANS, e registros de deslocamentos de veículos através de GPS para a distribuição espaço-temporal do fluxo veicular. Para o cálculo de emissões foi desenvolvido um software open source chamado VEIN (Vehicular Emissions Inventories, disponível em https://github.com/ibarraespinosa/vein). As emissões simuladas para as regiões metropolitanas de São Paulo são maiores do que as emissões estimadas pela CETESB para todos os poluentes. A partir destes cenários, foram realizadas simulações de qualidade do ar com o modelo WRF-Chem. Os resultados variam para os diferentes poluentes. De uma forma geral, a variação diurna dos poluentes é bem simulada, mostrando que as emissões estão consistentes. Apesar dos maiores valores de emissão encontrados neste trabalho, as concentrações simuladas dos poluentes primários foi, em média, menor do que as concentrações observadas. Isto provavelmente é decorrente do fato dos ventos simulados serem mais fortes do que os ventos observados. Este trabalho mostra novos métodos para desenvolver inventários de emissões com diferentes dados fornecendo um novo enfoque para compreender os problemas de qualidade do ar. / In this work, the impact of different vehicle emission inventory scenarios on air quality in the metropolitan areas of São Paulo, Baixada Santista, Vale do Paraíba, Sorocaba and Campinas is investigated. The construction of bottom-up vehicular emissions inventories is complex, being necessary to aggregate diverse information, such as the composition of the vehicle fleet (with the distribution of age, types of vehicles, types of fuel) and the emitting processes (emission factors for cold starts, exhaust and evaporative emissions). In addition, for air quality models, these emissions must still be distributed in time and space. The scenarios were constructed using different data sources, highlighting traffic simulations and vehicle counting of CET and SPTRANS, and records of vehicular displacements through GPS for the spatial-temporal distribution of vehicular flow. For the calculation of emissions, an open source software called VEIN (Vehicular Emissions Inventories, available at https://github.com/ibarraespinosa/vein) was developed. The simulated emissions for the metropolitan regions of São Paulo are larger than the emissions estimated by CETESB for all pollutants. From these scenarios, air quality simulations were performed with the WRF-Chem model. The results vary for different pollutants. In general, the daily variation of the pollutants is well simulated, showing that emissions are consistent. Despite the higher emission values found in this work, the simulated concentrations of the primary pollutants were, on average, lower than the observed concentrations. This is probably due to the fact that the simulated winds are stronger than the observed winds. This work shows new methods to develop emission inventories with different data providing a new approach to understanding air quality problems.
65

Modelagem da poluição atmosférica em São Paulo utilizando inventários de emissões veiculares bottom-up / Air pollution modeling in São Paulo using bottom-up vehicular emissions inventories

Sergio Alejandro Ibarra Espinosa 27 October 2017 (has links)
Neste trabalho, investiga-se o impacto de diferentes cenários de inventários de emissões veiculares na qualidade do ar nas regiões metropolitanas de São Paulo, Baixada Santista, Vale do Paraíba, Sorocaba e Campinas. A construção de inventários de emissões veiculares bottom-up é complexa, tendo que agregar informações diversas, como a composição da frota veicular (com a distribuição de idade, tipos de veículos, tipos de combustível) e os processos emissores (fatores de emissão para partidas a frio, emissões de escapamento e evaporativas). Além disso, para modelos de qualidade do ar, estas emissões ainda devem ser distribuídas no tempo e no espaço. Os cenários foram construidos utilizando diferentes fontes de dados, destacando-se as simulações de tráfego e contagem de veículos da CET e SPTRANS, e registros de deslocamentos de veículos através de GPS para a distribuição espaço-temporal do fluxo veicular. Para o cálculo de emissões foi desenvolvido um software open source chamado VEIN (Vehicular Emissions Inventories, disponível em https://github.com/ibarraespinosa/vein). As emissões simuladas para as regiões metropolitanas de São Paulo são maiores do que as emissões estimadas pela CETESB para todos os poluentes. A partir destes cenários, foram realizadas simulações de qualidade do ar com o modelo WRF-Chem. Os resultados variam para os diferentes poluentes. De uma forma geral, a variação diurna dos poluentes é bem simulada, mostrando que as emissões estão consistentes. Apesar dos maiores valores de emissão encontrados neste trabalho, as concentrações simuladas dos poluentes primários foi, em média, menor do que as concentrações observadas. Isto provavelmente é decorrente do fato dos ventos simulados serem mais fortes do que os ventos observados. Este trabalho mostra novos métodos para desenvolver inventários de emissões com diferentes dados fornecendo um novo enfoque para compreender os problemas de qualidade do ar. / In this work, the impact of different vehicle emission inventory scenarios on air quality in the metropolitan areas of São Paulo, Baixada Santista, Vale do Paraíba, Sorocaba and Campinas is investigated. The construction of bottom-up vehicular emissions inventories is complex, being necessary to aggregate diverse information, such as the composition of the vehicle fleet (with the distribution of age, types of vehicles, types of fuel) and the emitting processes (emission factors for cold starts, exhaust and evaporative emissions). In addition, for air quality models, these emissions must still be distributed in time and space. The scenarios were constructed using different data sources, highlighting traffic simulations and vehicle counting of CET and SPTRANS, and records of vehicular displacements through GPS for the spatial-temporal distribution of vehicular flow. For the calculation of emissions, an open source software called VEIN (Vehicular Emissions Inventories, available at https://github.com/ibarraespinosa/vein) was developed. The simulated emissions for the metropolitan regions of São Paulo are larger than the emissions estimated by CETESB for all pollutants. From these scenarios, air quality simulations were performed with the WRF-Chem model. The results vary for different pollutants. In general, the daily variation of the pollutants is well simulated, showing that emissions are consistent. Despite the higher emission values found in this work, the simulated concentrations of the primary pollutants were, on average, lower than the observed concentrations. This is probably due to the fact that the simulated winds are stronger than the observed winds. This work shows new methods to develop emission inventories with different data providing a new approach to understanding air quality problems.
66

IMPACTO DA INFUSÃO MESENTÉRICA DE COMPOSTOS NITROGENADOS SOBRE O FLUXO VISCERAL DE METABÓLITOS EM OVINOS / IMPACT OF NITROGENOUS COMPOUNDS MESENTERIC INFUSION ON METABOLITES VISCERAL FLOW IN SHEEP

Stefanello, Simone 16 February 2016 (has links)
Fundação de Amparo a Pesquisa no Estado do Rio Grande do Sul / The aim of the study is measure the impact of the mesenteric infusion of different N compounds: alanine, arginine and ammonium bicarbonate on oxygen uptake by splanchnic tissues relative the ureagenesis and gluconeogenesis. In an attempt to quantify the digestibility diet initially and after visceral metabolism, a trial with four multicatheterized wethers (45±2 kg body weight) was conducted as a 4 × 4 Latin Square feeding Tifton hay (2,5 %) and protein concentrate (0,7%) with 210 minutes daily periods during 4 days. The data obtained in the digestibility trial were complementary to those obtained in metabolism trial. The blood flow through portal- drained viscera (PDV) and total splanchnic tissues (ST) were determined by downstream dilution of 15 g/L p-aminohippurate (PAH) infused continuously (1.5mL/min) into the mesenteric vein. In parallel, wethers were continually infused into the mesenteric vein with aphysiological saline (0.15 MNaCl) solution during 90 minutes followed by the infusion, during more 120 minutes, of either solution: physiological saline (control), 0.25 MNH4HCO3, 0.25 M L-alanine or 0.125 M L-arginine, all of them infused at a rate of 1.5 mL/min to provide 375 μmol N/min. The infusion of nitrogenous compounds and their greater hepatic uptake increased hepatic O2 spent as a result of an increase in ureagenesis, which was not observed for gluconeogenesis. The higher ammonia portal circulation increases urea synthesis and thus the energy cost. O2 expense associated with the urea synthesis is higher than O2 expense related to gluconeogenesis. Increased alanine or arginine uptake by liver did not change the cost of O2. Moreover, it was not possible to compare the amino acids in study, since the infusion of arginine did not change any of the variables examined. / O objetivo do estudo foi avaliar o impacto da ureagênese e da neoglicogênese sobre o gasto visceral de oxigênio e se a infusão mesentérica de arginina, alanina e bicarbonato de amônio aumentam o consumo de energia pelo sistema visceral. Também foi avaliado se há diferença no gasto de energia pelos tecidos viscerais em função do tipo de composto nitrogenado infundido. Foram conduzidos dois ensaios com ovinos, sendo um para avaliar a digestibilidade da dieta e outro para avaliar parâmetros relacionados ao metabolismo visceral. Foram utilizados quatro ovinos machos (45±2 kg de peso corporal) com catéteres permanentes implantados cirurgicamente, em um delineamento experimental Quadrado Latino 4x4 alimentados com feno de tifton + concentrado em quantidades restritas a 2,5% PV para a oferta de volumoso e 0,7% PV para a oferta de concentrado. Os dados obtidos no ensaio de digestibilidade foram complementares aos obtidos no ensaio de metabolismo. Os animais passaram por quatro períodos com duração de um dia, onde em cada período foi infundido um dos tratamentos, sendo eles: solução fisiológica (controle), alanina, arginina e bicarbonato de amônio, totalizando quatro dias consecutivos de avaliação por animal. As infusões foram efetuadas na veia mesentérica com o auxílio de uma bomba de infusão contínua com capacidade de infundir concomitantemente o tratamento e o marcador de fluxo sanguíneo (PAH). Foram obtidas amostras de sangue em três diferentes pontos, sendo eles: artéria carótida, veia hepática e veia porta, em diferentes horários. Foram realizadas análises de gasometria, hematócrito e concentração sanguínea dos nutrientes: glicose, ureia, amônia, hemoglobina e de ácido paramino-hipúrico. A infusão de compostos nitrogenados e maior captação hepática dos mesmos, aumentou o gasto hepático de O2 como consequência de um aumento na ureagênese, o que não foi observado para a neoglicogênese. O incremento da circulação portal de amônia aumenta a síntese de ureia e consequentemente o custo energético. O gasto de O2 associado à síntese de ureia é maior do que o gasto de O2 relacionado à neoglicogênese. O aumento da carga hepática de alanina ou de arginina não alterou o gasto de O2 por este órgão. Ainda, não foi possível comparar os aminoácidos em estudo, visto que a infusão de arginina não alterou nenhuma das variáveis observadas.
67

Sicherheit und Effizienz der Pulmonalvenenablation nach Start eines neuen Ablationsprogramms zur Behandlung von Patienten mit symptomatischem Vorhofflimmern / Safety and efficiency of pulmonary vein ablation after starting a new ablation program for treatment in patients with atrial fibrillation

Könemann, Michel 27 April 2016 (has links)
Einleitung: Die zirkumferentielle Pulmonalvenenablation (CPVA) hat sich in den letzten Jahren als effektive Therapie bei Vorhofflimmern etabliert. Die Initiierung eines CPVA-Programms bleibt jedoch aufgrund der Komplexität der Prozedur und des Risikos lebensgefährlicher Komplikationen eine Herausforderung. Das Ziel dieser prospektiven Studie war es, die Effizienz und Sicherheit eines neuetablierten CPVA-Programms an einem medizinischen Zentrum mit zuvor wenig erfahrenen Untersuchern zu evaluieren.  Methoden und Ergebnisse: Zwischen 2006 und 2011 wurden 331 Patienten mit paroxysmalem und persistierendem Vorhofflimmern konsekutiv der zirkumferentiellen Pulmonalvenenablation zugeführt und unterzogen sich insgesamt 500 Prozeduren. Das mittlere Follow-Up betrug 648 ± 315 Tage. Die zunehmende Ablationspraxis führte neben der Prozessoptimierung zu einer deutlichen Reduzierung schwerwiegender Komplikationen. Prozedurdauer und Komplikationsrate erreichten nach 100 Ablationen ein stabiles und im Lichte der internationalen Literatur adäquates Niveau. Die Inzidenz schwerwiegender Komplikationen verringerte sich auf 1,3 - 1,9%. Insgesamt betrug der Anteil schwerwiegender Komplikationen 4%. Der Tod trat nicht auf. Keine der aufgetretenen Komplikationen führte zu einer permanenten Gesundheitsbeeinträchtigung der Patienten. Die Erfolgsraten waren seit Beginn des Programms auf einem konstanten Niveau und vergleichbar mit in der Literatur beschriebenen Werten.  Schlussfolgerung: Die vorliegende Studie zeigt, dass es gelingt, ein CPVA-Programm mit zuvor wenig erfahrenen Untersuchern effizient zu etablieren. Die Daten zeigen jedoch auch, dass mit einer erhöhten Komplikationsrate in der frühen Etablierungsphase zu rechnen ist. Nach 1,6 ± 0,7 Ablationen und einer Nachbeobachtung von einem Jahr waren 81,3% (266 / 327) der Patienten frei von symptomatischem Vorhofflimmern. Die Reablation ist eine wichtige Maßnahme, um die Erfolgsrate nachhaltig zu verbessern. Die Studie identifizierte Frührezidive innerhalb der Blanking-Periode und einen vergrößerten linken Vorhof als unabhängige Prädiktoren für die Rekurrenz von symptomatischem Vorhofflimmern.  Vor dem Hintergrund des steigenden Bedarfs an effektiven Therapien zur Behandlung von Vorhofflimmern sind die Ergebnisse dieser Studie hilfreich, um weitere CPVA-Programme zu planen und zu etablieren.
68

Leads to improve atrial fibrillation ablation, catheters, imaging and mapping guidance / Des pistes pour améliorer l’ablation de la fibrillation auriculaire, du catheter a l’imagerie en passant par la cartographie

Al Jefairi, Nora 04 December 2017 (has links)
La fibrillation auriculaire (FA) est la forme la plus fréquente d'arythmie cardiaque chez l’Homme. L'isolement des veines pulmonaires (VP) par radiofréquence (RF) est le traitement de référence pour les patients atteints de fibrillation auriculaire paroxystique (FAP) réfractaire symptomatique malgré le traitement médicamenteux. L’isolation des VP fonctionne très bien pour traiter les FA paroxystiques mais elle a un rôle limité dans le traitement des patients atteints de FA persistante (FAPs). La FA persistante est en effet plus complexe, en raison du développement dans l'oreillette gauche (OG) d’un substrat arythmogène résultant d’un remodelage électrique et anatomique. Ce substrat maintient la FA et nécessite donc des ablations supplémentaires dans l’OG (en dehors des veines pulmonaires). Les récidives de fibrillation auriculaire sont principalement dues à la reconnexion électrique des veines pulmonaires. C’est un phénomène fréquent, qui limite le succès de la procédure à long terme. Certaines séries rapportent de 20 à 50% de récidive, avec un impact important pour le patient, et pour le système de santé puisque générant des hospitalisations et des procédures répétées. L'ablation point par point utilisant un cathéter d’ablation à électrode unique peut être techniquement complexe. De ce fait, les lésions transmurales, contiguës et pérennes sont parfois difficiles et longues à réaliser, expliquant pour une part les taux élevés de reconnexion. Par conséquent, de nouveaux types de cathéters d’ablation ont été développés. On citera par exemple : les cathéters ballons de cryoablation, les cathéters d’ablation circulaire à électrodes multiples (PVAC et nMARQ), sont maintenant disponibles et ont pour but la création de lésions complètes et continues. Cependant, le ballon de cryoablation a des limites, notamment dans sa capacité à s'adapter à la variabilité anatomique des VP et pour l'ablation des sites extra-veineux. La conséquence est qu’un cathéter d’ablation supplémentaire doit être utilisé pour l’ablation des sites extra-veineux ce qui rend la procédure plus complexe et coûteuse. L’absence d'irrigation du cathéter PVAC augmente sans doute le risque de complications thromboemboliques. Le cathéter nMARQ en revanche est un cathéter circulaire irrigué qui, en plus de son rôle dans l’isolation des VP, permet l'ablation de substrat en dehors des veines pulmonaires. Par ailleurs, les outils de cartographie et d'imagerie cardiaques sont de plus en plus couramment utilisés pour planifier et guider l'ablation de FA. On citera la cartographie électroanatomique invasive (Carto®3) et non invasive (ECVUETM), la tomodensitométrie (TDM) et l'imagerie par résonance magnétique (IRM). Nous avons émis l'hypothèse que différentes stratégies et technologies pourraient améliorer la procédure et les résultats de l’isolation des VP en produisant de meilleures lésions et en permettant une visualisation directe des lésions. Nous avons donc évalué le rôle du cathéter circulaire irriguée pour la cartographie et l’ablation (nMARQ) dans la FAP et la FAPs avec ou sans guidage non invasif par ECGi. Nous nous sommes également intéressés à l’analyse en IRM des lésions produites par ce cathéter lors de l’isolation des veines pulmonaires. À cette fin, les données de l’isolation des VP ont été obtenues et traitées de manière aiguë et à 3 mois. Le suivi clinique a été évalué à 1 an. La thèse se compose de 3 parties : Partie 1 : Comment améliorer l'isolation des veines pulmonaires chez les patients atteints de fibrillation auriculaire paroxystique ? Partie 2 : Cathéter circulaire multiélectrodes et ablation de fibrillation auriculaire persistante. Partie 3 : Rôle de l'imagerie par résonance magnétique dans l'évaluation de la reconnexion des veines pulmonaires après l'isolement des veines pulmonaires ? / Atrial fibrillation (AF) is the most common form of cardiac arrhythmia in Humans. Pulmonary vein isolation (PVI) by radiofrequency (RF) ablation is the mainstay treatment for patients with symptomatic and drug refractory paroxysmal atrial fibrillation (PAF) as ectopic beats (triggers) from pulmonary veins (PVs) initiate AF, however PVI alone had limited role in treating patients with persistent atrial fibrillation (PsAF), due to additional involvement in left atrium (LA) by electrical and anatomical remodeling, creating more complex substrate (fibrosis) that maintain AF and therefore necessitate non-PV sites ablation to modify the arhythmogenic substrate. Atrial fibrillation recurrence mainly due to pulmonary vein (PV) electrical reconnection is common and remains the current issue that limits long term procedural success and generates extra costs due to repeated hospital admissions and repeated procedures. Point by point ablation using single tip catheter can be challenging, complex and time consuming, enhancing electrical reconnection as stable lesions are difficult to achieve. To overcome these limitations, new type of catheters such as balloon (cryoablation) and multi-electrode circular ablation catheters like PVAC and nMARQ, are now available. However, cryoablation balloon is limited by inability to adapt to anatomic PV variability and to ablate non-PV sites. This means that an additional ablation catheter has to be used for non-PV targets, and it certainly adds to the costs. The PVAC catheter lacks of irrigation increases the risk of thromboembolic complications. On contrary, nMARQ is an irrigated circular ablation catheter which in addition to its role in PVI, allows for non-PV/LA substrate ablation. Cardiac mapping and imaging tools are now commonly used to plan and guide AF ablation, such as invasive (Carto 3) and noninvasive (ECVUE) electroanatomic mapping (EAM), computed tomography (CT) and magnetic resonance imaging (MRI), respectively. We hypothesized that different strategies and technologies could improve PVI procedure and outcome by producing better lesions and by allowing for direct visualization of lesions. We therefore, assessed the role of circular, irrigated mapping and ablation catheter (nMARQ) in PAF and PsAF with or without noninvasive ECGi guidance, and advanced imaging technologies (MRI) after PVI. For that purpose, PVI data were obtained and processed acutely and at 3 months. Clinical follow up was evaluated at 1 year. The thesis consists of 3 parts: Part 1: How to improve pulmonary vein isolation lesion formation in patients with paroxysmal atrial fibrillation? Part 2: Circular catheter and persistant atrial fibrillation ablation. Part 3: The role for magnetic resonance imaging in assessing pulmonary vein reconnection after pulmonary vein isolation?
69

A trajetória de construção e validação dos diagnósticos de enfermagem: trauma vascular e risco para trauma vascular / The process of construction and validation of the nursing diagnoses: vascular trauma and risk of vascular trauma

Arreguy-Sena, Cristina 14 March 2002 (has links)
Ao percorremos a trajetória de construção dos diagnósticos de enfermagem \"Trauma vascular\" e \"risco para trauma vascular\", buscamos, no capítulo 1, apresentar a classificação dos tipos de veias superficiais periféricas de adolescentes, adultos e idosos, segundo as características de uma veia passível de ser puncionada para fins terapêuticos e de diagnóstico, com base na aplicação da técnica Delphi, envolvendo juízes de quatro categorias profissionais distintas (angiologistas, anestesistas, enfermeiros e bioquímicos). Obtivemos índice de concordância para totalmente adequado/pertinente de mais de 90% e menos de 10% para moderadamente adequado/pertinente nos 13 critérios, a saber: mobilidade; trajeto; inserção/derivação; calibre; visibilidade; palpação e localização, tendo, como referencia: a articulação; localização da veia, tendo como referência, sua anatomia; regularidade do diâmetro do trajeto venoso; consistência do trajeto venoso; solução de continuidade das paredes do vaso; facilidade de punção e outros critérios a serem incluídos. No segundo capítulo, apresentamos a construção dos elementos (titulo, características definidoras, fatores relacionados) do diagnóstico de enfermagem \"trauma vascular\" e dos elementos (título e fatores de risco) para o diagnóstico de enfermagem \"Risco para trauma vascular\", baseando-nos na revisão literária e em nossa experiência profissional, e a validação de seus respectivos componentes, segundo o modelo de Fhering (1986) e adaptação do mesmo aos fatores relacionados e aos fatores de risco. Participaram 60 peritos. Reafirmamos: das 18 características definidoras analisadas, 15 são maiores (ponto de corte >=0,8) e 1 menor (ponto de corte >=0,50 ou <0,80); dos 14 fatores relacionados analisados, todos tiveram aceitação, sendo que 11 deles obtiveram escores de media ponderada >=0,8 e, dos 51 fatores de riscos analisados, 8 foram aprovados com escores >=0,50 para as situações ligadas a medicação e a forma/periodicidade de infusão; 4 foram aprovados para situações ligadas ao dispositivo endovenoso e seu tempo de permanência num mesmo sítio de inserção; 5 foram aprovados para situações ligadas a fixação do dispositivo endovenoso; 10 foram aprovados para situações ligadas ao indivíduo, seus hábitos, padrão de comunicação, estilo de vida e capacidade sensório-motora e 20 aprovados para as situações ligadas as decisões profissionais, a política institucional e ao procedimento propriamente. Finalmente, no capítulo 3, apresentamos validação clínica de alguns componentes do diagnóstico \"trauma vascular\" e \"Risco para trauma vascular\", utilizando um estudo de coorte, quando foram avaliadas 323 pessoas e 427 sítios de inserção de dispositivos endovenosos. Obtivemos significância no teste de ajuste do modelo para um conjunto de nove variáveis passíveis de serem transpostas para populações similares, merecendo destaque o tempo de permanência do dispositivo num mesmo sítio de inserção e a qualidade da fixação dos dispositivos (se fixos ou frouxos). Outros fatores mostraram-se relevantes somente para a população do estudo. / As we investigate the process of the construction of nursing diagnoses (vascular trauma and/or Risk of vascular trauma), we intend to classify, in the first chapter, the types of peripheral surface veins of teenage, adult, and elderly patients, according to the characteristics of a vein that can be punctured for therapeutic and diagnostics purposes, based on the application of the Delphi technique, judged by people from our different professional categories (angiologists, anesthetists, nurses and biochemists). We obtained a C.I. of over 90% for totally adequate/pertinent and less than 10% for moderately adequate/pertinent for the 13 criteria applied: mobility, course, insertion/derivation, caliber, visibility, palpation and localization with reference to the joint, location of the vein with reference to its anatomical structure, regulation of the diameter of the venous course, consistency of the venous course, continuity of the vessel tissue, how easy it is to puncture the vein, and other criteria to be included. In chapter 2, we present the construction of the elements (name, defining features, related factors) of the nursing diagnosis \"vascular trauma\" and of the elements (name, risk factor) of the nursing diagnosis \"risk of vascular trauma\", based on our reading of the existing literature and on our work experience, and the validation of their respective components as in Fhering´s (1986) model, and the adaptation of these to the related factors and risk factors. 60 experts took part. To summarize: of the 18 defining features analyzed, 15 were found to be greater (cut-off point >=0,8) and one smaller (cut-off point >=0,5 and <=0,8); of the 14 related factors analyzed, all met with approval, 11 of them with weighted average scores greater than or equal to 0,8 and of the 51 risk factors analyzed, 8 were approved with scores over 0,5 for situations connected with medication and the manner or intervals of infusion; 4 were approved for situations connected with the intravenous device and the time it remained in the same place of insertion, 5 were approved for situations connected with the individual, his/her habits, standard of communication, lifestyle and sensory-motor ability, and 20 were approved for situations connected with professional decisions, institutional policies and the procedure itself. Finally, in chapter 3, we present the clinical validation of some components of the diagnoses \"vascular trauma\" and \"risk of vascular trauma\", using a group study; our observations were based on 323 people and 427 point of insertion of the intravenous device. The results of the model adjustment test were significant tor a set of nine variables which may be transposed to similar populations. The most prominent of these variables were the time the device remained in one place of insertion and the quality of fixing of the devices (whether they were fixed or loose). Other factors were shown to be relevant only for the population under study.
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A trajetória de construção e validação dos diagnósticos de enfermagem: trauma vascular e risco para trauma vascular / The process of construction and validation of the nursing diagnoses: vascular trauma and risk of vascular trauma

Cristina Arreguy-Sena 14 March 2002 (has links)
Ao percorremos a trajetória de construção dos diagnósticos de enfermagem \"Trauma vascular\" e \"risco para trauma vascular\", buscamos, no capítulo 1, apresentar a classificação dos tipos de veias superficiais periféricas de adolescentes, adultos e idosos, segundo as características de uma veia passível de ser puncionada para fins terapêuticos e de diagnóstico, com base na aplicação da técnica Delphi, envolvendo juízes de quatro categorias profissionais distintas (angiologistas, anestesistas, enfermeiros e bioquímicos). Obtivemos índice de concordância para totalmente adequado/pertinente de mais de 90% e menos de 10% para moderadamente adequado/pertinente nos 13 critérios, a saber: mobilidade; trajeto; inserção/derivação; calibre; visibilidade; palpação e localização, tendo, como referencia: a articulação; localização da veia, tendo como referência, sua anatomia; regularidade do diâmetro do trajeto venoso; consistência do trajeto venoso; solução de continuidade das paredes do vaso; facilidade de punção e outros critérios a serem incluídos. No segundo capítulo, apresentamos a construção dos elementos (titulo, características definidoras, fatores relacionados) do diagnóstico de enfermagem \"trauma vascular\" e dos elementos (título e fatores de risco) para o diagnóstico de enfermagem \"Risco para trauma vascular\", baseando-nos na revisão literária e em nossa experiência profissional, e a validação de seus respectivos componentes, segundo o modelo de Fhering (1986) e adaptação do mesmo aos fatores relacionados e aos fatores de risco. Participaram 60 peritos. Reafirmamos: das 18 características definidoras analisadas, 15 são maiores (ponto de corte >=0,8) e 1 menor (ponto de corte >=0,50 ou <0,80); dos 14 fatores relacionados analisados, todos tiveram aceitação, sendo que 11 deles obtiveram escores de media ponderada >=0,8 e, dos 51 fatores de riscos analisados, 8 foram aprovados com escores >=0,50 para as situações ligadas a medicação e a forma/periodicidade de infusão; 4 foram aprovados para situações ligadas ao dispositivo endovenoso e seu tempo de permanência num mesmo sítio de inserção; 5 foram aprovados para situações ligadas a fixação do dispositivo endovenoso; 10 foram aprovados para situações ligadas ao indivíduo, seus hábitos, padrão de comunicação, estilo de vida e capacidade sensório-motora e 20 aprovados para as situações ligadas as decisões profissionais, a política institucional e ao procedimento propriamente. Finalmente, no capítulo 3, apresentamos validação clínica de alguns componentes do diagnóstico \"trauma vascular\" e \"Risco para trauma vascular\", utilizando um estudo de coorte, quando foram avaliadas 323 pessoas e 427 sítios de inserção de dispositivos endovenosos. Obtivemos significância no teste de ajuste do modelo para um conjunto de nove variáveis passíveis de serem transpostas para populações similares, merecendo destaque o tempo de permanência do dispositivo num mesmo sítio de inserção e a qualidade da fixação dos dispositivos (se fixos ou frouxos). Outros fatores mostraram-se relevantes somente para a população do estudo. / As we investigate the process of the construction of nursing diagnoses (vascular trauma and/or Risk of vascular trauma), we intend to classify, in the first chapter, the types of peripheral surface veins of teenage, adult, and elderly patients, according to the characteristics of a vein that can be punctured for therapeutic and diagnostics purposes, based on the application of the Delphi technique, judged by people from our different professional categories (angiologists, anesthetists, nurses and biochemists). We obtained a C.I. of over 90% for totally adequate/pertinent and less than 10% for moderately adequate/pertinent for the 13 criteria applied: mobility, course, insertion/derivation, caliber, visibility, palpation and localization with reference to the joint, location of the vein with reference to its anatomical structure, regulation of the diameter of the venous course, consistency of the venous course, continuity of the vessel tissue, how easy it is to puncture the vein, and other criteria to be included. In chapter 2, we present the construction of the elements (name, defining features, related factors) of the nursing diagnosis \"vascular trauma\" and of the elements (name, risk factor) of the nursing diagnosis \"risk of vascular trauma\", based on our reading of the existing literature and on our work experience, and the validation of their respective components as in Fhering´s (1986) model, and the adaptation of these to the related factors and risk factors. 60 experts took part. To summarize: of the 18 defining features analyzed, 15 were found to be greater (cut-off point >=0,8) and one smaller (cut-off point >=0,5 and <=0,8); of the 14 related factors analyzed, all met with approval, 11 of them with weighted average scores greater than or equal to 0,8 and of the 51 risk factors analyzed, 8 were approved with scores over 0,5 for situations connected with medication and the manner or intervals of infusion; 4 were approved for situations connected with the intravenous device and the time it remained in the same place of insertion, 5 were approved for situations connected with the individual, his/her habits, standard of communication, lifestyle and sensory-motor ability, and 20 were approved for situations connected with professional decisions, institutional policies and the procedure itself. Finally, in chapter 3, we present the clinical validation of some components of the diagnoses \"vascular trauma\" and \"risk of vascular trauma\", using a group study; our observations were based on 323 people and 427 point of insertion of the intravenous device. The results of the model adjustment test were significant tor a set of nine variables which may be transposed to similar populations. The most prominent of these variables were the time the device remained in one place of insertion and the quality of fixing of the devices (whether they were fixed or loose). Other factors were shown to be relevant only for the population under study.

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