Titre de l'écran-titre (visionné le 25 mars 2024) / Dans la région de Trois-Rivières au Québec, environ 4 000 édifices résidentiels et commerciaux ont développé d'importants indices d'endommagement associés à la présence de sulfures de fer (notamment de la pyrrhotite et de la pyrite) dans les particules du gros granulat utilisé dans la fabrication du béton. Cette détérioration est due à l'oxydation des sulfures de fer en particulier la pyrrhotite qui génèrent des nouveaux produits plus volumineux. Ces derniers entraînent le gonflement, la fissuration et même la désagrégation progressive du béton. Ce projet consiste à étudier une série d'échantillons de granulats à des teneurs en soufre total (S$_\textup{T}$) contrôlées pour apprécier l'impact de la proportion des sulfures de fer et tenter d'établir, par l'entremise de l'essai de consommation d'oxygène et de l'essai d'expansion sur barres de mortier, un seuil critique au-delà duquel la durabilité des infrastructures pourra potentiellement être affectée pour le granulat étudié. Des analyses chimiques ont été réalisées pour quantifier les quantités de S$_\textup{T}$ des échantillons provenant de la carrière Maskimo (MSK 0,2 et MSK 0,8) et sur le granulat de référence PKA (granulat non réactif). Ces granulats ont été mélangés par la suite jusqu'à produire des échantillons à différentes concentrations de ST (0,10 %, 0,15 %, 0,25 %, 0,50 % et 0,75 %). Le comportement nuisible potentiel de ces mélanges a ensuite été évalué par l'entremise de l'essai d'expansion sur barres de mortier et l'essai de consommation d'oxygène. L'essai de consommation d'oxygène permet d'évaluer quantitativement le potentiel d'oxydation des sulfures de fer incorporés dans les granulats à béton. Cette technique mesure le taux de consommation d'oxygène dans la partie supérieure d'un cylindre fermé contenant une couche de matériau fin compacté afin de déterminer son potentiel d'oxydation. Des paramètres optimisés pour évaluer le potentiel d'oxydation des granulats dans cet essai comprennent une taille de particules inférieure à 150 μm (50 % 0-75 μm et 50 % 75-150 μm), une saturation de 40 %, une couche de 10 cm d'épaisseur de granulats compactés et un dégagement de 10 cm dans la partie supérieure du cylindre. La durée est de trois heures après un temps de stabilisation de 30 minutes, le tout à 22 °C. L'essai d'expansion sur barres de mortier permet de suivre l'expansion des barres fabriquées avec les granulats à différentes concentrations en S$_\textup{T}$. L'essai consiste en un conditionnement de 90 jours à 80 °C/80 % humidité relative, avec deux cycles de mouillage/séchage par semaine ; un cycle de mouillage de trois heures dans une solution d'eau de javel à 6 %, et un cycle de séchage de trois jours (Phase I), suivi d'une période pouvant atteindre 90 jours et plus de conditionnement à 4 °C/100 % humidité relative (HR) (Phase II). Les deux périodes (3 heures) hebdomadaires de trempages en solution d'eau de javel à 6 % sont maintenues durant la deuxième phase de l'essai. Une analyse pétrographique (méthode de la calculette) et une analyse chimique semi-quantitative (microfluorescence-X) ont été effectuées sur des plaques polies fabriquées à partir des granulats provenant de la carrière Maskimo et de la carrière PKA pour distinguer et quantifier les sulfures de fer présents dans les particules du gros granulat. Les résultats des travaux effectués ont montré que la teneur en S$_\textup{T}$ contribue à l'augmentation du potentiel d'oxydation des mélanges testés mais elle n'explique pas à elle seule le phénomène de détérioration. La teneur en pyrrhotite est largement responsable du comportement problématique des granulats MSK étudiés. L'essai de consommation d'oxygène et l'essai d'expansion sur barres de mortier ont la capacité de refléter l'impact de la proportion des sulfures de fer, notamment la pyrrhotite, sur la détérioration du béton. Cependant, selon les travaux réalisés dans le cadre de cette étude, ces essais ne permettent pas pour le moment de déterminer précisément les teneurs seuils en pyrrhotite qu'il ne faut pas dépasser dans les granulats à béton. Une étude plus approfondie devra être effectuée sur une plus grande variété d'échantillons. Finalement, la méthode de μXRF permet de déterminer les quantités de sulfures de fer présents dans les granulats testés, même ceux qui ont une faible teneur. Par contre, la méthode pétrographique de la calculette n'a pas permis une quantification fiable des proportions des différents sulfures de fer présents dans les granulats étudiés et reste toujours subjective car elle dépend de l'expérience du pétrographe qui fait les identifications et estime visuellement les teneurs en sulfures.

Résumé : Cette étude examine l'impact de la taille et de la gradation de particules sur les corrélations théoriques et empiriques existantes les plus connues entre la résistance au cisaillement et le comportement dilatatant des matériaux granulaires en condition de déformation plane et en compression triaxiale drainée. À cette fin, 276 tests de cisaillements symétriques directs et 35 tests de compressions triaxiales drainées ont été menés sur des échantillons composés de billes de basalte (particules rondes), et de sables constitués de particules angulaires (sable de Péribonka et sable d'Eastmain) sur une échelle de 63 µm à 2000 µm afin d'évaluer leur résistance au cisaillement et leur comportement de dilatance sur une vaste échelle de pressions normales et de densités relatives initiales. Premièrement, la fiabilité et l'applicabilité des limites de mesure à l’aide de tests physiques de cisaillements symétriques directs dans l'interprétation de la résistance au cisaillement frictionnel en déformation plane des matériaux granulaires ont été discutées et confirmées par l'usage du code informatique DEM, SiGran. L'accent a été particulièrement mis sur la validation du modèle DEM au moyen de comparaison des résultats des simulations DEM avec leurs équivalents physiques à une échelle macro. Les résultats virtuels DSA sont abordés du point de vue de la coaxialité entre les principales tensions et les principales directions des paliers de pression ainsi que de la déviation de la direction d'extension nulle à partir de la direction horizontale. Les résultats numériques fournissent également des données quantitatives sur les différentes formes d'énergie consommées durant le cisaillement confirmées par d'autres résultats physiques et numériques publiés. Sur la base des postulats précédents, un examen minutieux des résultats des essais de cisaillements directs et de données issues de la littérature a été accompli afin d'évaluer la fiabilité des formules empiriques bien connues de Bolton et Collins et al. avec leurs constantes couramment employées en condition de déformation plane. L'étude montre qu'une application des relations empiriques de force-dilatation de cisaillement avec les constantes proposées par Bolton (1986) et Collins et al. (1992) aux sables ayant une distribution de taille de particules différente peut conduire à surestimer leurs valeurs en terme de force de cisaillement. Dans cette étude, les coefficients des équations de Bolton et Collins et al. ont donc été ajustée afin de prendre en compte les caractéristiques des particules, en particulier le diamètre médian, D50. De manière analogue, les effets microstructuraux imposés par la géométrie interne des particules (par exemple la taille, la forme et la gradation des particules) sur la relation tension-dilatation très connue, celle de Rowe (1962), et son ajustement empirique en condition triaxiale drainée ont été examinés dans cette étude. Une comparaison des prédictions des formules proposées avec les données de force de cisaillement issues de la littérature fournit de nombreuses preuves en faveur des contraintes mises en place au sein des relations existantes de force-dilatation de cisaillement en condition de déformation plane et triaxiale. Ces comparaisons prouvent également que la prise en compte de la taille des grains conduit à des résultats plus tangibles que lorsque la taille de la particule n'est pas considérée. Les formules de force-dilatation ajustées peuvent se révéler avantageuses pour évaluer indépendamment la cohérence des forces de cisaillement déterminées expérimentalement et pour introduire des lois d’écoulement plus précises dans les analyses géotechniques analytiques et numériques. / Abstract : The present study examines more closely the potential impact of particle size and gradation on the most famous existing theoretical and empirical correlations between the shear strength and the dilation behavior of granular materials in plane strain and drained triaxial compression conditions. For this purpose, 276 symmetrical direct shear and 35 drained triaxial compression tests have been carried out on samples made up of basalt beads (rounded particles), and sands consisting of angular particles (Péribonka sand and Eastmain sand) in the range of 63 µm to 2000 µm to evaluate their shear resistance and dilation behavior over a wide range of normal pressures and initial relative densities. First, the reliability and applicability of boundary measurements in physical symmetrical direct shear tests to interpret the plane strain frictional shearing resistance of granular material have been discussed and confirmed using DEM computer code SiGran. Particular emphasis is placed on the validation of the DEM model by comparing the results of DEM simulations with their physical counterparts at the macro-scale. The virtual DSA results are discussed in terms of the coaxiality between the principal stresses and the principal strains increments directions as well as the deviation of the zero extension direction from the horizontal direction. The numerical results also provide quantitative data on different forms of energy consumed during shearing confirming other published physical and numerical results found in the literature. Following the assumptions above, a close scrutiny of symmetrical direct shear test results and strength and dilation data from the literature have been done to evaluate the reliability of well-known empirical Bolton’s and Collins et al.’s formulations with their commonly used constants in plane strain condition. The study shows that an application of empirical shear strength-dilation relationships with the constants proposed by Bolton (1986) and Collins et al. (1992) to sands with different particle-size distribution may strongly over-predict their shear strength values. In this study, the coefficients of Bolton’s and Collins et al.’s equations have been, therefore, adjusted to account for particle characteristics, in particular for D50. Similarly, the microstructural effects imposed by internal particle geometry (e.g. particle-size, particle shape, and particle gradation) on most popular stress-dilatancy relationship of Rowe (1962), and its empirical adjustment in drained triaxial condition have been investigated in this study. A comparison of the predictions by the proposed formulas with shear strength data from the literature provides evidences in support of the implemented constraints into existing shear strength-dilation relations in plane strain and drained triaxial conditions. These comparisons also proves that accounting for the grain size yields more authentic results than when particle size is not considered. The adjusted strength-dilation formulas may be beneficial for independently assessing the consistency of the experimentally-determined shear strengths, and introducing more refined flow rules into analytical and numerical geotechnical analyses.

Preeclampsia is one of the leading causes of maternal and fetal mortality and morbidity. Furthermore, women who have had preeclampsia have an increased risk of cardiovascular events over the next 10-15 years. Indeed, preeclampsia is associated with a four-fold increase in the risk of hypertension and double the risk of fatal and non fatal ischaemic heart disease and stroke. In addition, offspring born to preeclampsia are more likely to have higher blood pressure from childhood and stroke in later life. The risk to mother and offspring is greatest when preeclampsia is diagnosed at an earlier gestation, suggesting a more severe form of preeclampsia. As the long term cardiovascular risk to both mother and child is known from delivery, the main interest of my research was to identify key phenotypic variations in mothers and children during the years between the episode of preeclampsia and emergence of established cardiovascular disease, which might explain the link between the two conditions. This information could then be used to devise ways to identify subjects at greatest risk of later cardiovascular disease and to establish intermediate endpoints for future preventative interventions. Therefore, in a case control study, women diagnosed with preeclampsia between 1998 and 2003 and their offspring were recruited and underwent comprehensive cardiovascular and metabolic phenotyping. Furthermore, young adults born preterm to hypertensive pregnancy were also investigated in their twenties. The research demonstrates that early-onset preeclampsia, diagnosed before 34 weeks gestation, is associated with blood pressure patterns in mothers 6-13 years after pregnancy that are distinct from those seen following later-onset disease. Furthermore, there is evidence of distinct differences in cardiac, vascular and metabolic profiles in these individuals with women having evidence of increased arterial stiffness, changes in cardiac function and reduced capillary density. Preterm offspring of hypertensive pregnancies similarly have higher blood pressure than seen in those born following late-onset disease and, in young adult life, have reduced endothelial function and changes in cardiac size proportional to this dysfunction. This research demonstrates adverse cardiac and vascular remodelling after preeclampsia in mothers and offspring that are evident before the development of clinical cardiovascular disease. The identified differences in cardiac and vascular function may be useful as surrogate endpoints in future preventive trials.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Une grande partie du patrimoine bâti provençal a été érigé à l’aide d’un matériau connu sous le nom de « Pierre du Midi ». L’exposition de ces pierres aux intempéries conduit à des dégradations particulières. Parmi celles-ci, la desquamation en plaques a la particularité de se développer en dehors des zones de remontées capillaires ainsi qu’en l’absence des facteurs communs de dégradation. Elle est donc induite par les propriétés intrinsèques du matériau. Ce travail a eu pour objectif d’en comprendre les mécanismes et d’établir le rôle joué par les minéraux argileux. La variabilité du degré de desquamation en plaques a tout d’abord été mise en évidence sur des monuments de périodes de construction équivalentes. Puis, un échantillonnage représentatif de cette variabilité a été mené en carrières. Le cortège argileux de chaque échantillon a été caractérisé en combinant la microscopie électronique en transmission, à la simulation des diffractogrammes de rayons X. La nature et la quantité de chacune des phases argileuses ont ainsi été déterminées et la quantité des feuillets expansifs peut être corrélée au degré de desquamation en plaques. Par ailleurs, les propriétés de stockage et de transfert des fluides de ces matériaux ont été évaluées. Elles ont permis d’appréhender les modalités de transport de l’eau et son impact sur les propriétés mécaniques. La combinaison de la perte de résistance mécanique et d’une forte dilatation au cours de la variation de la teneur en eau semble être à l’origine du processus de desquamation en plaques. Ce travail permet en outre de définir des critères de sélection de pierres de remplacement pertinents du point de vue de leur durabilité. / Most of the Provence built heritage was erected using a material named « Pierre du Midi ». The natural weathering of these limestones leads to specific deterioration patterns. Among these, spalling tends to develop in areas apart from capillary rise and free from the commun decay factors. This phenomenon seems induced by the intrinsic properties of the material. The present study aims to understand the mechanisms at play and to establish the role of the clay minerals. A wide variability of spalling degree has been observed on historical buildings of equivalent construction periods. A representative sampling of the different limestones types has thus been realized in the respective quarries. The clay minerals assemblage of each sample has been defined thanks to an adapted methodological approach combining TEM-EDX characterization to XRD profile modeling. It allowed determining both the nature and the quantity of each clay mineral phase. The link between the expansive layers quantity and the spalling degree has been evidenced. The storage and transport properties of the different types of limestones were also defined. Moreover, the macroscopic behavior upon water content variation was assessed through dilation and compressive strength experiences. The results suggest that the mechanism leading to spalling decay is triggered by the interaction between the expansive clay mineral layers and the water molecules. The hydromechanic behavior of the stone constitutes the macroscopic symptom of this interaction. This behavior is highly controlled by the fluid storage and transport properties that condition the macroscopic transmission of the deformation.

This work is a numerical and analytical study of wave motion through dynamic materials (DM). This work focuses on showing several results that greatly extend the applicability of the checkerboard focusing effect. First, it is shown that it is possible to simultaneously focus dilatation and shear waves propagating through a linear elastic checkerboard structure. Next, it is shown that the focusing effect found for the original €œperfect€� checkerboard extends to the case of the checkerboard with smooth transitions between materials, this is termed a functionally graded (FG) checkerboard. With the additional assumption of a linear transition region, it is shown that there is a region of existence for limit cycles that takes the shape of a parallelogram in (m,n)-space. Similar to the perfect case, this is termed a €œplateau€� region. This shows that the robustness of the characteristic focusing effect is preserved even when the interfaces between materials are relaxed. Lastly, by using finite volume methods with limiting and adaptive mesh refinement, it is shown that energy accumulation is present for the functionally graded checkerboard as well as for the checkerboard with non-matching wave impedances. The main contribution of this work was to show that the characteristic focusing effect is highly robust and exists even under much more general assumptions than originally made. Furthermore, it provides a tool to assist future material engineers in constructing such structures. To this effect, exact bounds are given regarding how much the original perfect checkerboard structure can be spoiled before losing the expected characteristic focusing behavior.

Das Standardmodell der Teilchenphysik hat sich bis heute, mit Ausnahme der allgemeinen Relativitätstheorie, als erfolgreichste Theorie zur Beschreibung der Natur erwiesen. Störungstheoretische Rechnungen für bestimmte Mengen in Quantenchromodynamik (QCD) haben bisher unerreicht präzise Vorraussagen ermöglicht, die experimentell nachgewiesen wurden. Trotz dieser Erfolge gibt es Teile des Standardmodells und Energieskalen bei denen die Störungstheorie versagt und man nach Alternativen suchen muss. Vieles können wir hierbei verstehen, indem wir eine ähnliche Theorie untersuchen, die sogenannte planare N=4 Super Yang-Millstheorie in vier Dimensionen (N=4 SYM). Es existieren viele Indizien dafür, dass die Theorie exakte Lösungen zulässt. Dies lässt sich zurückführen auf die Integrabilität der Theorie, eine unendlich dimensionale Symmetriealgebra, die die Theorie stark einschränkt. Neben besagter Integrabilität besitzt diese Theorie auch andere spezielle Eigenschaften. So ist sie des am besten verstandenen Beispiels der Eich-/Gravitations Dualität durch die AdS/CFT Korrespondenz. Ausserdem sind die Streuamplituden von Gluonen auf Baumgraphenniveau in N=4 SYM die selben wie in Quantenchromodynamik. Diese Streuamplituden besitzen eine elegante Struktur und stellen sich als deutlich simpler heraus, als die dazugehörigen Feynmangraphen vermuten lassen. Tatsächlich umgehen viele der zur Berechnung von Streuamplituden entwickelten Masseschalenmethoden die Feynmangraphen, indem sie vorrübergehend manifeste Unitarität und Lokalität aufgeben und dadurch die Rechnungen stark vereinfachen. Alle diese Entwicklungen suggerieren, dass der konventionelle Formalismus der Theorie mit Hilfe der Wirkung im Minkowskiraum nicht der aufschlussreichste oder effizienteste Weg ist, die Theorie zu untersuchen. Diese Arbeit untersucht der Hypothese, ob dass stattdessen Twistorvariablen besser geeignet sind, die Theorie zu beschreiben. Der Twistorformalismus wurde zuerst von Roger Penrose eingeführt. Auf dem klassischen Level ist die holomorphe Chern-Simonstheorie im Twistorraum äquivalent zur klassischen selbst-dualen Yang-Mills Lösung in der Raumzeit. Die volle Twistorwirkung, welche eine Störung um diesen klassisch integrablen Sektor ist und durch eine Eichbedingung auf die N=4 SYM Wirkung reduziert werden kann, produziert unter einer anderen Eichbedingung alle sogenannten maximalhelizitätsverletzenden (MHV) Amplituden auf Baumgraphenniveau. Durch die Einführung eines Twistorpropagators konnten auch NkMHV Amplituden effizient beschrieben werden. In dieser Arbeit erweitern wir den Twistorformalismus um auch Größen, die sich nicht auf den Masseschalen befinden, beschreiben zu können. Wir untersuchen alle lokalen eichinvarianten zusammengesetzten Operatoren im Twistorraum und zeigen, dass sie alle Baumgraphenniveau-Formfaktoren des sogenannten MHV-Typs erzeugen. Wir erweitern diese Methode zu NMHV und öher NkMHW Level in Anlehnung an die Amplituden. Schliess lich knüpfen wir an die Integrabilität an, indem wir den ein-Schleifen Dilatationsoperator in dem skalaren Sektor der Theorie im Twistorraum berechnen. / The Standard Model of particle physics has proven to be, with the exception of general relativity, the most accurate description of nature to this day. Perturbative calculations for certain quantities in Quantum Chromo Dynamics (QCD) have led to the highest precision predictions that have been experimentally verified. However, for certain sectors and energy regimes, perturbation theory breaks down and one must look for alternative methods. Much can be learned from studying a close cousin of the standard model, called planar N = 4 super Yang-Mills theory in four dimensions (N = 4 SYM), for which a lot of evidence exists that it admits exact solutions. This exact solvability is due to its quantum integrability, a hidden infinite symmetry algebra that greatly constrains the theory, which has led to a lot of progress in solving the spectral problem. Integrability aside, this non-Abelian quantum field theory is special in yet other ways. For example, it is the most well understood example of a gauge/gravity duality via the AdS/CFT correspondence. Furthermore, at tree level the scattering amplitudes in its gluon sector coincide with those of Quantum Chromo Dynamics. These scattering amplitudes exhibit a very elegant structure and are much simpler than the corresponding Feynman diagram calculation would suggest. Indeed, many on-shell methods that have been developed for computing these scattering amplitudes circumvent the tedious Feynman calculation, by giving up manifest unitarity and locality at intermediate stages of the calculation, greatly simplifying the work. All these developments suggest that the conventional way in which the theory is presented, i.e. in terms of the well- known action on Minkowski space, might not be the most revealing or in any case not the most efficient way. This thesis investigates whether instead twistor variables provide a more suitable description. The twistor formalism was first introduced by Roger Penrose. At the classical level, a holomorphic Chern-Simons theory on twistor space is equivalent to classically integrable self-dual Yang-Mills solutions in space-time. A quantum perturbation around this classically integrable sector reduces to the conventional N = 4 SYM action by imposing a partial gauge condition. This action generates all so-called maximally helicity violating (MHV) amplitudes at tree level directly, when a different gauge was chosen. By including a twistor propagator into the formalism, also higher degree NkMHV amplitudes can be described efficiently. In this thesis we extend this twistor formalism to encompass (partially) off-shell quantities. We describe all gauge-invariant local composite operators in twistor space and show that they immediately generate all tree-level form factors of the MHV type. We use the formalism to compute form factors at NMHV and higher NkMHV level in parallel to how this was done for amplitudes. Finally, we move on to integrability by computing the one-loop dilatation operator in the scalar sector of the theory in twistor space.

O presente estudo avaliou comparativamente o padrão hemodinâmico e a presença de vasodilatação intrapulmonar antes e após tratamento cirúrgico tardio (> 2 anos) da hipertensão portal através da desconexão ázigo portal com esplenectomia (DAPE) e anastomose esplenorenal distal (AERD) na esquistossomose mansônica forma hepatoesplênica. Foram estudados prospectivamente 37 pacientes portadores de hipertensão portal secundária a esquistossomose mansônica confirmada por biópsia hepática , sendo 21 pacientes do sexo masculino e 16 do sexo feminino, com idade média de 46,6 + 12 anos, no período de janeiro de 2007 a dezembro de 2008. A avaliação do padrão hemodinâmico sistêmico foi realizada através do Doppler transesofágico (Cardio QÒ) e da ecocardiografia bidimensional com Doppler nos pacientes dos grupos AERD (n=13) e DAPE (n=15) . Os resultados obtidos foram comparados com grupo controle constituído por 10 pacientes sem hipertensão portal submetidos à endoscopia digestiva alta para avaliação de dispepsia. A avaliação da presença de síndrome hepatopulmonar foi realizada em todos os pacientes através da ecocardiografia contrastada com infusão salina 0,9% nos grupos DAPE (n=15), AERD (n=13) e pré-operatório (n=9). Os pacientes que apresentavam vasodilatação intrapulmonar no período pré-operatório repetiram o exame após 30 dias do procedimento cirúrgico. Em relação ao padrão hemodinâmico sistêmico observou-se aumento significativo (p =0,001) do débito cardíaco no grupo AERD (5,08 ± 0,91 L/min) em relação ao controle (4,17 ± 0,52 L/min). Ao contrário, os pacientes submetidos à DAPE (4,36 ± 0,59 L/min) não apresentaram diferença estatística significante (p = 0,47) em relação ao controle (4,17 ± 0,52 L/min). Os pacientes do grupo AERD apresentaram aumento estatisticamente significante (p = 0,001) do volume sistólico (60,1 + 5,6 ml) em relação ao controle (53,2 + 5,6 ml), enquanto que não houve diferença significativa (p = 0,41) nos pacientes submetidos à DAPE (56 ± 9,4 ml) . Não houve diferença estatisticamente significante entre os valores médios da freqüência cardíaca e da pressão arterial sistêmica em relação ao controle (AERD, p= 0,22 , DAPE, p = 0,91), (AERD, p = 0,40, DAPE , p = 0,06), respectivamente. Em relação a ecocardiografia bidimensional com doppler observou-se aumento estatisticamente significante (p = 0,0001) do diâmetro diastólico do ventrículo esquerdo (DDVE) nos pacientes submetidos à AERD (55,4 ± xviii 4,25 mm) em relação ao período pré-operatório (48,4 ± 4,4 mm), fato este não observado nos pacientes submetidos à DAPE (50 ± 3,26 mm, p = 0,25). O volume diastólico final do ventrículo esquerdo (VDF) apresentou diferença estatisticamente significante (p = 0,00001) nos pacientes submetidos à AERD (172,7 ± 40,7 ml) em relação ao período pré-operatório (116,3 ± 31,3 ml). Não foi observada diferença estatisticamente significante do VDF dos pacientes submetidos à DAPE (126,9 ± 25,2 ml) em relação ao período pré-operatório (p = 0,31). Em relação ao diâmetro sistólico do ventrículo esquerdo (DSVE) observou-se aumento estatisticamente significante (p = 0,0004) nos pacientes submetidos à AERD (36 ± 3,8 mm) em relação ao período pré-operatório (30,6 ± 2,4 mm). Os pacientes do grupo DAPE (32,5 ± 3 mm) não apresentaram diferença estatisticamente significante em relação ao período pré-operatório (p = 0,06 ). O volume sistólico final do ventrículo esquerdo (VSF) apresentou diferença estatisticamente significante ( p = 0,001) e dentro do valores da normalidade nos pacientes submetidos à AERD (48,4 ± 16,1 ml) em relação ao período pré-operatório (29,1 ± 6,5 ml). Os pacientes do grupo DAPE (35 ±10,6 ml) não apresentaram diferença estatisticamente significante da média do VSF em relação ao período pré-operatório (p = 0,06). Observou-se diminuição estatisticamente significante (p = 0,006) e dentro dos valores da normalidade na média da fração de ejeção (FE) nos pacientes submetidos à AERD (70,9 ± 2,6%) em relação ao período pré-operatório (74,4± 3,6%). Os pacientes submetidos à DAPE (72 ± 3,5%) não apresentaram diferença estatisticamente significante (p = 0,06) em relação ao período pré-operatório. Em relação à fração de encurtamento da fibra miocárdica (Delta D%), observou-se diminuição estatisticamente significante (p = 0,03) e dentro dos valores da normalidade nos pacientes submetidos à AERD (34,5 ± 2,2%) em relação ao período pré-operatório (36,7± 3%). Os pacientes submetidos à DAPE (34,9 ± 2,7%) não apresentaram diferença estatisticamente significante na média do Delta D% em relação ao controle (p = 0,10). Em relação ao átrio esquerdo (AE), observou-se aumento estatisticamente significante (p = 0,002) nos pacientes submetidos à AERD (40,7 ± 4,6mm) em comparação ao pré-operatório (35,2 ± 4,3 mm). Não foi observada diferença estatisticamente significante no tamanho do AE nos pacientes submetidos à DAPE (37,4 ± 4,1 mm) em relação ao período pré-operatório (p = 0,16). A espessura do septo intraventricular nos grupos DAPE (8,64 ± 1,71 mm,) e AERD (8,84 ± 1,16 mm) não apresentou diferença estatisticamente significante quando comparados ao período pré-operatório (p = 0,81 , p = 0,78) respectivamente. A análise da parede posterior do ventrículo esquerdo (PP) dos grupos DAPE (8,50 ± 1,67mm) e AERD (8,38 ± 1mm) não apresentou diferença estatisticamente significativa quando comparado ao período pré-operatório (p = 0,83, p = 0,54) respectivamente. Em relação ao ecocardiograma contrastado observou-se a presença de vasodilatação intrapulmonar em 9 pacientes (60%) submetidos à DAPE, 9 pacientes (69%) submetidos à AERD e 5 pacientes (55%) no período préoperatório. Neste último grupo a repetição do exame 30 dias após tratamento cirúrgico com técnica de desconexão demonstrou desaparecimento da vasodilatação intrapulmonar em 3 de 4 pacientes, visto que um dos pacientes que apresentou VIP foi excluído após identificação de adenocarcinoma pela biópsia hepática realizada no intra-operatório. Observou-se em apenas um dos 23 pacientes portadores de vasodilatação intrapulmonar alargamento do gradiente alvéolo arterial de oxigênio > 15 mmHg, caracterizando a presença de síndrome hepatopulmonar. Em conclusão, os pacientes no pós-operatório tardio de AERD apresentam padrão hemodinâmico caracterizado por aumento do débito cardíaco e sobrecarga volumétrica com dilatação das cavidades ventriculares esquerdas ao contrário dos pacientes submetidos à DAPE, que mantém debito cardíaco similar à população normal e sem sobrecarga das cavidades esquerdas ou comprometimento funcional do miocárdio. Estas alterações são secundárias ao aumento do retorno venoso determinado pela manutenção do baço e da anastomose esplenorenal distal. Embora a vasodilatação intrapulmonar seja observada em 62 % (23 de 37 pacientes) dos pacientes com hipertensão portal secundária a forma hepatoesplênica da esquistossomose mansônica, independente da técnica cirúrgica utilizada para seu tratamento, a síndrome hepatopulmonar foi observada em apenas 2,7 % dos pacientes / This study is a comparative analysis of the hemodynamic pattern and presence of intrapulmonary vasodilatation in hepatoesplenic mansoni schistosomiasis before and after surgical treatment (> 2 years) of portal hypertension by esophagogastric devascularization with splenectomy (EGDS) and distal splenorenal shunt (DSRS). 37 patients with portal hypertension secondary to hepatosplenic mansoni schistosomiasis confirmed by liver biopsy were prospectively studied between January 2007 to December 2008. 21 patients were male and 16 were female, with an mean age of 46.6 +12 years. The hemodynamic evaluation was performed by transesophageal doppler (Cardio QÒ) and Doppler echocardiography in DSRS (n=13) and EGDS (n=15) patients. The results were compared with a control group of 10 patients without portal hypertension submitted to upper digestive endoscopy for dyspepsia evaluation The presence of pulmonary vasodilatation was evaluated in all patients by contrastenhanced echocardiography with saline solution 0,9% in DSRS (n=15), EGDS (n=13) and preoperative (n=9) groups. Patients with intrapulmonary vasodilation in the preoperative period repeated the exam 30 days after surgical treatment of portal hypertension by a devascularization procedure. Systemic hemodynamic evaluation by transesophageal Doppler revealed a significant increase in cardiac output (p =0.001) in the DSRS (5,08 ± 0,91 L/min) patients in relation to control group (4,17 ± 0,52 L/min). By contrast, patients submitted to EGDS (4,36 ± 0,59 L/min) present no increase in cardiac output (p = 0.47) when compared with control group (4,17 ± 0,52 L/min). The DSRS patients presented a statistically significant increase (p = 0.001) in systolic volume (60,1 + 5,6 ml) in relation to the control (53,2 + 5,6 ml), while no significant difference (p = 0.41) was observed in EGDS group (56 ± 9,4 ml). There was no statistically significant difference between heart rate and mean arterial pressure between groups (EGDS, p= 0,22, DSRS, p = 0,91), (EGDS, p = 0,40, DSRS, p = 0,06), respectively. The bidimensional Doppler echocardiography evaluation demonstrated a statistically significant increase (p = 0,0001) in left ventricular diastolic diameter (LVDD) in DSRS patients (55,4 ± 4,25 mm) in relation to the preoperative period (48,4 ± 4,4 mm) while there was no difference in patients submitted to EGDS (50 ± 3,26 mm, p = 0,25). Patients submitted to DSRS presented a statistically significant increase (p = 0,00001) in left ventricular end-diastolic volume (LVEDV) in (172,7 ± 40,7 ml) in relation to the preoperative period (116,3 ± 31,3 ml). No statistically significant difference was found in LVEDV in the patients submitted to DSRS (126,9 ± 25,2 ml; p = 0,31). Patients submitted to DSRS presented a statistically significant increase (p = 0,0004) in left ventricular systolic diameter (36 ± 3,8 mm) in relation to the preoperative period (30,6 ± 2,4 mm) while patients in the EGDS group (32,5mm ± 3) did not present any statistically significant difference (p = 0,06). There was also a statistically significant increase (p = 0,001), nevertheless within normal values, in left ventricular end-systolic volume (LVESV) in patients submitted to DSRS (48,4 ± 16,1 ml) in relation to the preoperative period (29,1 ± 6,5 ml). In contrast, EGDS patients (35 ± 10,6 ml) presented no significant difference in LVSV in relation to the preoperative group (p = 0,06). A statistically significant decrease within normal values was observed (p = 0,006) for mean ejection fraction (FE) in patients submitted to DSRS (70,9 ± 2,6%) in relation to the preoperative period (74,4± 3,6%) while EGDS group (72 ± 3,5%) did not present any statistically difference (p = 0,06) . Patients submitted to DSRS also presented a significant decrease (p = 0,03), within the normal values in myocardial fibers shortening fraction (34,5 ± 2,2%) in relation to the preoperative period (36,7± 3%) while no significant difference (p = 0.10) was observed in patients submitted to EGDS (34,9 ± 2,7%). A statistically significant increase in left atrium (LA) was observed (p = 0,002) in the patients submitted to DSRS (40,7 ± 4,6mm) in relation to the preoperative period (35,2 ± 4,3 mm). No statistically significant difference (p = 0,16) was observed in LA diameter in the patients submitted to EGDS (37,4 ± 4,1mm) in relation to the preoperative period. There was no statistically significant difference in intraventricular septum thickness in both DSRS (8,64 ± 1,71mm,) and EGDS (8,84 ± 1,16mm) groups when compared to the preoperative period (p = 0,81; p = 0,78, respectively.) Also, there was no statistically significant difference in left ventricular posterior wall (PW) in both DSRS (8,50 ± 1,67mm) and EGDS (8,38 ± 1mm) groups when compared with the preoperative period (p = 0,83; p = 0,54, respectively). Intrapulmonary vasodilation was observed in 9 patients (69%) submitted to DSRS, 9 patients (60%) submitted to EGDS, and 5 patients (55%) in the preoperative period by contrast-enhanced echocardiography. The same exam, repeated In the latter group 30 days after surgical treatment of schistosomal portal hypertension with a disconnection procedure, showed disappearance of the intrapulmonary vasodilatation in 3 out of 4 patients. In spite of great prevalence of intrapulmonary vasodilatation in all groups, widening of the arterial oxygen gradient > 15 mmHg, characterizing the hepatopulmonary syndrome, was observed in only one patient. In conclusion, patients submitted to DSRS presented systemic hemodynamics characterized by an increase in cardiac output and left ventricular dilatation secondary to volemic overload unlike patients submitted to EGDS, which maintained cardiac output similar to control patients without overload or functional myocardial impairment of left ventricle. These hemodynamics differences may be due to the presence of the spleen and the distal splenorenal anastomosis. Intrapulmonary vasodilation was observed xxv in 62% of the patients with portal hypertension secondary to the hepatosplenic mansonic schistosomiasis, irrespective of the surgical technique. Nevertheless, hepatopulmonary syndrome was observed in just 2.7% of the patients

INTRODUÇÃO: O transplante hepático é a terapêutica de escolha para pacientes com hepatopatias avançadas. Melhorias na seleção dos pacientes, avanços cirúrgicos e imunológicos aumentaram a sobrevida. As complicações biliares ocorrem em 15 a 35% dos transplantes e estão associadas a técnicas de redução hepática. A estenose anastomótica ocorre de 5 a 34% e pode ser tratada por cirurgia, acesso endoscópico ou percutâneo. Esse último apresenta bons resultados, mas carece de padronização, critérios de sucesso ou consenso quanto aos fatores que influenciam a resposta terapêutica. Neste trabalho, avaliou-se a relação entre os fatores de risco e a terapêutica, resposta mais adequada, dados de maior relação com a estenose da anastomose bílio-entérica, período de surgimento, tempo de drenagem mais adequado, incidência de complicações, eficácia e segurança terapêutica. MÉTODOS: No período de março de 1993 a maio de 2006, foram avaliadas trinta e cinco pacientes com estenose da anastomose bílio-entérica após o transplante hepático prospectiva e retrospectivamente. Trinta e quatro (97,1%) tinham idade igual ou superior a um ano. Vinte e quatro (68%) tinham mais de 10 kg. Houve compatibilidade ABO em 100%, entre gêneros em 28,6% e na relação de peso entre receptor e doador em 71,4%. A principal indicação foi atresia de vias biliares e 45% dos transplantes foram realizados com doadores vivos. Trinta transplantes (86%) foram eletivos e 18 pacientes (51,4%) foram submetidos previamente à cirurgia de Kasai. A reconstrução biliar foi feita por meio da anastomose bílio-entérica em todos os pacientes. As estenoses foram confirmadas por colangiografia percutânea, dilatadas e drenadas. O calibre dos drenos foi aumentado nas reintervenções, sendo trocado a cada três meses e mantido por pelo menos seis meses. As complicações foram avaliadas e os pacientes foram distribuídos em grupos de resposta terapêutica de G1 a G4. RESULTADOS: Febre, icterícia, exame histopatológico demonstrando padrão obstrutivo biliar e dosagem elevada de gamaglutamiltransferase estiveram mais presentes no grupo com estenose. Os pacientes submetidos à cirurgia de Kasai apresentaram melhor resposta ao tratamento percutâneo (p = 0,05). As outras variáveis não demonstraram correlação estatisticamente significativa com a melhor ou pior resposta ao tratamento. Observou-se tempo médio de drenagem de 10 meses no grupo G1, onde houve menor ocorrência de complicações. CONCLUSÕES: Houve resposta satisfatória nos grupos com uma ou duas sessões (86%) de tratamento percutâneo. A cirurgia de Kasai se associa com melhores respostas ao tratamento; o exame histopatológico demonstrando padrão obstrutivo biliar e a elevação de gamaglutamiltransferase apresentam maior relação com a estenose, que ocorreu mais freqüentemente após o primeiro ano do transplante. Os pacientes drenados por mais de seis meses apresentaram melhores resultados. Entretanto, o prolongamento da drenagem associa-se com mais complicações. O tratamento percutâneo (dilatação e drenagem) é eficaz, seguro, com baixa taxa de complicações. / INTRODUCTION: Hepatic transplant is the chosen therapy for patients with advanced hepathopathy. Improvement on patients selection, surgical and immunologic advances increases the life expectancy. Biliary complications occur between 15 to 35% transplants and are associated to hepatic reduction techniques. The anastimotic stenosis occur between 5 to 14% and can be treated by surgery, endoscopic access or percutaneous. This last one presents fair results. However, it lacks of standard type, success criteria and consensus regarding to therapeutics response. Along this work, we evaluated the relation between risk factors and therapeutic, most adequate response, higher relation data of anastomotic bilioenteric stenosis, appearance period, most adequate time of drainage, incidence of complications, security and effectiveness therapeutic. METHODS: During the period of March 1993 to May 2006, 35 patients with anastomotic bilioenteric stenosis after having hepatic transplant prospective and retrospectively were evaluated. 34 of them (97.1%) were at the age of one year of above. 24 (68%) weighted more than 10kg. There was ABO compatibility in 100%, between genders in 28.6%, and 71.4% in relation to weight between receptor and donator. The main indication was biliary atresia ducts and 45% of transplants were made with living donators. 30 transplants (86%) were elective and 18 patients (51.4%) were previously submitted to Kasai surgery. The biliar reconstruction was made through anastomosis bilioenteric in all patients, The stenosis were confirmed by percutaneous colangiography, expanded and drained. The drain caliber was enlarged during the re-intervention, changed each 3 months and kept for at least 6 months. Complications were evaluated and the patients were allotted in groups according to G1 and G4 therapeutic response . RESULTS: fever, jaundice/icterus, hystopatologic exam with obstructed biliary pattern and high levels of gamaglutamitransferase were all presented in stenosis group. Patients submitted to Kasai surgery presented better response to the percutaneous treatment (p = 0.05). The other varieties did not demonstrate any statistically relevant association including better or worse response to the treatment. For group G1 were occurred less complications, 10 months of drainage was found as medium period. CONCLUSIONS: There was a satisfactory response in the groups with one or two sessions (86%) of percutaneous treatment. Kasai surgery is associated to the best responses to the treatment; hystopatologic exam with obstructed biliary pattern and elevation of gamaglutamitransferase presented better relation to stenosis, which have occurred more often after the first year of the transplant. Patients that have been drained for more than six months presented better results. However, the drainage extension is connected to more complications. The percutaneous treatment (expansion and drainage) is effective, with low complications rate.

Ma, Yan. / "Ca" in the title is subscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 143-166). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.