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Influence of biomechanical force and mass transfer on the progression of atherosclerosis in human carotid arteriesKim, Sungho 06 July 2011 (has links)
Atherosclerosis is a vascular degenerative disease leading to progressive thickening in the intima of large and medium sized arteries through the formation of plaque that is very rich with cholesterol. The cholesterol is carried by LDL (low density lipoprotein) particles which pass through the endothelium and accumulate in the intima. The passage of LDL is influenced by wall shear stress which activates physiological responses of the endothelium. However, the causal relationship between the physiological responses and their effect on LDL mass transport is not fully understood. To obtain blood flow patterns in human carotid arteries, a fluid structure interaction (FSI) computational approach is employed, based on the in-vivo arterial geometry constructed from black blood magnetic resonance images (BBMRI) and flow rate boundary conditions obtained from phase contrast images (PC). Wall shear stress (WSS) on the luminal surface is computed, and this variable is related to the formation of leaky junctions, which is a major transendothelial pathway for LDL. A model for the fraction of leaky junction at a surface is incorporated into the overall computational scheme for mass transport, along with pore theory.
The theoretical model is applied to images from three human carotid arteries in which the degree of disease ranges from mild to moderate. Maximum mass flux is predicted to be in the downstream region of stenoses where WSS is low, and this result is consistent with the clinical observation of plaque progression downstream of the stenosis. The hypothesis that the majority of LDL enters into the intima through leaky junctions is supported by observation of similar distributions between the pattern of volume flux via leaky junctions and mass flux. These studies suggest that mass flux of LDL can be a predictor to indicate areas with potential for plaque formation and progression in human carotid artery disease.
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Placa aterosclerótica à angiotomografia de coronárias em pacientes com escore de cálcio zero / Atherosclerotic plaque to coronary angiotomography in patients with a zero calcium scoreGabriel, Fabíola Santos 02 June 2017 (has links)
Background: In view of the high mortality due to Cardiovascular Diseases in the world,
a stratification of the main risk factors and correct choice of the diagnostic modality is
necessary. Several studies have shown that the calcium score (CS) has a low risk of
cardiovascular events. However, the frequency of individuals with coronary
atherosclerotic plaques and zero CS is conflicting in the specialized medical literature.
Objective: To evaluate the frequency of coronary atherosclerotic plaques and
associated factors in patients with CS.
Methods: This was a prospective, cross-sectional study with 367 volunteers with zero
CS through the realization CS test and coronary computed tomography angiography
(CCTA), from 2011 to 2016, in four imaging centers. The sample was obtained for
convenience and consecutively.
Results: The frequency of atherosclerotic plaque in the coronary arteries of the 367
patients with zero CS was 9.3% (34 individuals); in this subgroup the mean age was 52
± 10 years, 18 (52.9%) were women and 16 (47%) had significant coronary obstructions
(> 50%), some in more than one segment. The frequency of non-obese individuals
(90.6% vs 9.4%, p = 0.037) and those of alcoholics (55.9% vs 44.1%, p = 0.015) was
significantly higher in patients with atherosclerotic plaques, Variable, odds ratio of 3.4 for
the development of these plaques.
Conclusions: The frequency of atherosclerotic plaque with zero CS was considerable,
evidencing that the absence of calcification, through the CCTA, does not exclude plaque
and nor obstructive lesion, mainly in the non-obese and the alcoholic. / Fundamento: Diante da alta mortalidade por Doenças Cardiovasculares no mundo fazse
necessário a estratificação dos principais fatores de riscos e escolha correta da
modalidade diagnóstica. Diversos estudos demonstraram que escore de cálcio (EC)
zero caracteriza baixo risco de eventos cardiovasculares. No entanto, a frequência de
indivíduos portadores de placa aterosclerótica coronária com EC zero é conflitante na
literatura médica especializada.
Objetivo: Avaliar a frequência de placa aterosclerótica coronária e fatores associados
em portadores de EC zero, assim como determinar o grau de obstrução das mesmas.
Métodos: Trata-se de estudo transversal, prospectivo e com 367 voluntários portadores
de EC zero mediante a realização de EC e angiotomografia computadorizada de
coronárias (ATCC), no período de 2011 a 2016, em quatro centro de imagens. A
amostra foi obtida por conveniência e de forma consecutiva.
Resultados: A frequência de placa aterosclerótica nas artérias coronárias dos 367
pacientes com EC zero foi de 9,3% (34 indivíduos); neste subgrupo a média de idade
foi de 52±10 anos, 18 (52,9%) eram mulheres e 16 (47%) exibiam obstruções
coronarianas significativas (> 50%), alguns em mais de um segmento. A frequência de
não obesos (90,6% vs 9,4%; p=0,037) e de etilistas (55,9% vs 44,1%; p=0,015) foi
significativamente maior nos portadores de placa aterosclerótica, apresentando, cada
variável, odds ratio de 3,4 para o desenvolvimento das referidas placas.
Conclusões: A frequência de placa aterosclerótica com EC zero foi considerável,
evidenciando que a ausência de calcificação, mediante a ATCC, não exclui placa e nem
lesão obstrutiva principalmente nos não obesos e etilistas.
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Investigação das modificações na geometria vascular nas bordas de stents farmacológicos e não-farmacológicos e a correlação com a composição dos ateromas: estudo seriado com ultrassom intracoronário e Histologia Virtual® / Investigation of the modifications in vascular geometry at the edges of bare-metal and drug-eluting stents and the correlation of modifications in plaque composition: a serial with grey-scale intravascular ultrasound and Virtual Histology(TM)José de Ribamar Costa Junior 07 July 2011 (has links)
Até o momento, pouco se sabe sobre a influência da modificação na composição do ateroma nas bordas dos stents e a ocorrência de alterações na geometria vascular. Este estudo objetiva correlacionar, utilizando de maneira seriada (pós-implante do stent e reestudo aos nove meses) o ultrassom monocromático e a Histologia Virtual®, as modificações na composição dos ateromas nas bordas proximais e distais de stents nãofarmacológicos e farmacológicos e as alterações ocorridas nas dimensões do vaso, luz e placa que possam explicar a ocorrência da reestenose nestes segmentos. Estudo prospectivo, de centro único, que randomizou (1:1) pacientes com síndrome coronária aguda para receberem stents nãofarmacológicos (Driver®, n=20 pacientes) ou farmacológicos (Cypher®, n=20 pacientes). Após a realização do procedimento, todos os pacientes submeteram-se a avaliação com ultrassom e Histologia Virtual®, que foi repetido ao final de nove meses de seguimento. O objetivo primário foi avaliar as modificações na área do vaso, luz e placa ao ultrassom e na composição do ateroma pela Histologia Virtual® no período entre o implante e o reestudo, buscando correlacionar as alterações no ateroma com as modificações na geometria vascular. Observou-se que na borda proximal, stents farmacológicos e não-farmacológicos tem um comportamento semelhante na avaliação ultrassonográfica, com tendência a remodelamento expansivo da área do vaso para compensar o crescimento na área da placa. Por outro lado, na borda distal, há menor crescimento da área da placa entre os pacientes tratados com stents farmacológicos, resultando em maior área da luz no reestudo de nove meses. Do ponto de vista da análise com Histologia virtual, nos dois grupos e em ambas as bordas houve redução do componente fibroso e núcleo necrótico com aumento no conteúdo fibrolipidico. Observou-se ainda importante correlação entre a variação do componente fibrótico e o aumento na área da placa (r=0.78, p=0.01). O uso de stents farmacológicos não se correlaciona com \"efeito de borda\". Ao contrário, parece haver menor crescimento da placa na borda distal destas endopróteses quando comparadas às sem fármaco. A modificação na composição do ateroma, com aumento do conteúdo fibro-lipídico pode explicar em parte estes achados. / To the present, little is known about the correlation between modifications in plaque composition at stent edges and the changes in vessel geometry. This study sought to evaluate, by serial grey-scale intravascular ultrasound (IVUS) and Virtual Histology(TM), the modifications in plaque composition at the edges of drug-eluting and bare-metal stents and the correlation of these findings with changes in the measuremntes of vessel, lumen and plaque area at those segments. Single-center, prospective and randomized (1:1) evaluation of 40 patients with acute coronary syndrome treated with bare-metal (Driver(TM), n=20 patients) or drug-eluting stents (Cypher(TM), n=20 patients). Following stent deployment, all individuals underwent gray scale IVUS and Virtual Histology(TM) evaluation, which were repeated at nine months. Primary endpoint included the modification in vessel, lumen and plaque area and in the composition of the plaque in the mean time between the baseline and follow-up procedure. Additionally, we tried to determine a correlation between plaque composition variation and changes in vessel geometry. At the proximal edge of both drug-eluting and bare-metal stents there was a trend to positive vessel remodeling which compensated the modest increase in plaque area. At the distal edge, patients treated with drug-eluting stents had less plaque growth resulting in a larger lumen area at follow-up. By Virtual Histology, there was a marked reduction in the % of fibrotic tissue and necrotic core in both edges of the two stents and a positive, strong correlation was seen between increase in % of fibrofatty component and augmentation in plaque area(r=0.78, p=0.01). The use of drug-eluting stents was not associated with \"edge effect\". On the contrary, patients treated with these devices experienced less plaque growth, especially at the distal edge of the stents. Modifications in plaque composition, with increase in fibrofatty content, might partially explain these findings.
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A Fluid Structure Interaction Model Of Intracoronary Atherosclerotic Plaque RuptureTeuma-Melago, Eric 01 January 2006 (has links)
Plaque rupture with superimposed thrombosis is the primary cause of acute coronary syndromes of unstable angina, myocardial infarction and sudden death. Although intensive studies in the past decade have shed light on the mechanism that causes unstable atheroma, none has directly addressed the clinical observation that most myocardial infarction (MI) patients have moderate stenoses (less than 50%). Considering the important role the arterial wall compliance and pulsitile blood flow play in atheroma rupture, fluid-structure interaction (FSI) phenomenon has been of interest in recent studies. In this thesis, the impact is investigated numerically of coupled blood flow and structural dynamics on coronary plaque rupture. The objective is to determine a unique index that can be used to characterize plaque rupture potential. The FSI index, developed in this study for the first time derives from the theory of buckling of thin-walled cylinder subjected to radial pressure. Several FSI indices are first defined by normalizing the predicted hemodynamic endothelial shear stress by the structural stresses, specifically, by the maximum principal stress (giving the ratio ), and the Von Mises stress (giving the ratio ). The predicted at the location of maximum (i.e { }) denoted , is then chosen to characterize plaque rupture through systematic investigation of a variety of plaque characteristics and simulated patient conditions. The conditions investigated include varying stenosis levels ranging from 20% to 70%, blood pressure drop ranging from 3125 Pa/m to 9375 Pa/m, fibrous cap thickness ranging from to , lipid pool location ranging from the leading to the trailing edge of plaque, lipid pool volume relative to stenosis volume ranging from 24% to 80%, Calcium volume relative to stenosis volume ranging from 24% to 80% and arterial remodeling. The predicted varies with the stenosis severity and indicates that the plaques investigated are prone to rupture at approximately 40-45% stenosis levels. It predicts that high pressure significantly lowers the threshold stenosis rate for plaque rupture. In addition, the plaque potential to rupture increases for relatively thin fibrous cap, lipid core located near the leading plaque shoulder, and dramatically for relative lipid pool volume above 60%. However, calcium deposit has marginal effect on plaque rupture. Overall, the predicted results are consistent with clinical observations, indicating that the has the potential to characterize plaque rupture when properly established. In the appendix, the unsteady flow in a collapsible tube model of a diseased artery is solved analytically. The novelty of our approach is that the set of governing equations is reduced to a single integro-differential equation in the transient state. The equation was solved using the finite difference method to obtain the pressure and compliant wall behavior. The analytical approach is less computer-intensive than solving the full set of governing equations. The predicted membrane deflection is quite large at low inlet velocity, suggesting possible approach to breakdown in equilibrium. As the transmural pressure increases with wall deflection, bulges appear at the ends of the membrane indicating critical stage of stability, consistent with previous studies. An increase in wall thickness reduces the wall deflection and ultimately results in its collapse. The collapse is due to breakdown in the balance of wall governing equation. An increase in internal pressure is required to maintain membrane stability.
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Segmentos coronarianos sem obstrução angiográfica em indivíduos com doença aterosclerótica coronária: caracterização através do ultrassom intravascular com histologia virtual / Coronary segments without luminal stenosis by angiography in patients with atherosclerotic coronary disease: a comprehensive evaluation with intravascular ultrasound and virtual histologyMorais, Gustavo Rique 25 September 2015 (has links)
Introdução: Segmentos coronários com doença aterosclerótica manifesta podem coexistir no mesmo paciente com artérias normais à angiografia. Porém as características desses vasos angiograficamente normais permanecem pouco estudadas. O presente estudo visa a descrição in vivo, através do ultrassom intravascular com histologia virtual, da presença, grau de acometimento e composição da doença coronária aterosclerótica em artérias normais ou quase normais (irregularidades parietais) do ponto de vista angiográfico, em pacientes com doença coronária obstrutiva em outros territórios. Métodos: Pacientes com doença coronária obstrutiva foram selecionados de forma prospectiva e foram submetidos a estudo ultrassonográfico com histologia virtual de múltiplos vasos. Artérias epicárdicas principais foram classificadas em quatro grupos baseado na sua aparência angiográfica: 1) vasos completamente normais, 2) vasos com irregularidades parietais, 3) vasos com pelo menos uma estenose discreta, 4) vasos com pelo menos uma estenose moderada ou importante. Para os vasos com estenoses luminais (grupos 3 e 4 acima), apenas segmentos que não possuíam lesão maior ou igual a 30% (não obstrutivos) foram incluídos na análise. Resultados: Um total de 60 pacientes (154 vasos) foram incluídos no estudo. Vasos angiograficamente normais apresentaram menor carga de placa, menos componente necrótico, menor densidade de lesões e quase nenhuma placa com características de alto risco. Entretanto, em vasos com irregularidades parietais encontramos uma maior carga de placa com elevada densidade de lesões pelo ultrassom intravascular similar a segmentos \"não obstrutivos\" de vasos com estenoses luminais evidentes pela angiografia em outro ponto. Conclusão: Artérias coronárias completamente normais pela angiografia parecem apresentar pouca doença aterosclerótica. Entretanto, vasos com irregularidades parietais estão associados com um maior acometimento aterosclerótico e elevada densidade placas de alto risco, achado este que não pode ser rapidamente obtido com o uso apenas da angiografia coronária / Background: Extensively diseased arteries may co-exist, in the same patient, with coronary vessels with a normal appearance by angiography. Thus far, however, the characteristics of the latter remain poorly described. The present study aims to evaluate in vivo, using intravascular ultrasound (IVUS) with radiofrequency backscatter analysis (RF), the presence, degree, and composition of atherosclerosis in arteries with angiographically normal or near-normal appearance, in patients with diagnosed coronary disease in other territories. Methods: Patients with diagnosed obstructive coronary disease were prospectively selected and underwent protocol-mandated multi-vessel IVUS-RF. Major epicardial branches were classified into four groups based on their angiographic appearance: 1) completely normal-looking; 2) near-normal; 3) at least one mild stenosis; 4) at least one severe or moderate stenosis. For vessels with lumen stenosis (groups 3 and 4 above), only \"non-stenotic\" portions were included in the IVUS analysis. Results: A total of 60 patients (154 vessels) comprised the study population. Completely normal-looking vessels had lower plaque burden, lower necrotic component, lower density of lesions, and almost null high-risk plaques. Conversely, a nearnormal aspect, with only subtle lumen irregularities by angiography, was associated with increased disease burden, with an elevated density of plaques with high-risk features, similar to \"non-stenotic\" portions of vessels with obvious atherosclerosis elsewhere. Conclusions: Coronary vessels with a completely normal-looking appearance by angiography appear to have little atherosclerosis. Conversely, yet mild luminal irregularities by angiography are associated with increased disease burden and elevated density of high-risk plaques by IVUS, which cannot be readily assessable by angiography alone. Descriptors: angiography; atherosclerosis; coronary artery disease; plaque, atherosclerotic; ultrasonography, interventional; coronary vessels.Background: Extensively diseased arteries may co-exist, in the same patient, with coronary vessels with a normal appearance by angiography. Thus far, however, the characteristics of the latter remain poorly described. The present study aims to evaluate in vivo, using intravascular ultrasound (IVUS) with radiofrequency backscatter analysis (RF), the presence, degree, and composition of atherosclerosis in arteries with angiographically normal or near-normal appearance, in patients with diagnosed coronary disease in other territories. Methods: Patients with diagnosed obstructive coronary disease were prospectively selected and underwent protocol-mandated multi-vessel IVUS-RF. Major epicardial branches were classified into four groups based on their angiographic appearance: 1) completely normal-looking; 2) near-normal; 3) at least one mild stenosis; 4) at least one severe or moderate stenosis. For vessels with lumen stenosis (groups 3 and 4 above), only \"non-stenotic\" portions were included in the IVUS analysis. Results: A total of 60 patients (154 vessels) comprised the study population. Completely normal-looking vessels had lower plaque burden, lower necrotic component, lower density of lesions, and almost null high-risk plaques. Conversely, a nearnormal aspect, with only subtle lumen irregularities by angiography, was associated with increased disease burden, with an elevated density of plaques with high-risk features, similar to \"non-stenotic\" portions of vessels with obvious atherosclerosis elsewhere. Conclusions: Coronary vessels with a completely normal-looking appearance by angiography appear to have little atherosclerosis. Conversely, yet mild luminal irregularities by angiography are associated with increased disease burden and elevated density of high-risk plaques by IVUS, which cannot be readily assessable by angiography alone
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Perfil nutricional, metabólico e risco cardiovascular em pacientes pós-transplante hepáticoAlves, Bruna Cherubini January 2016 (has links)
No pós-transplante hepático (pós-TxHep), complicações da doença cardiovascular (CV) têm sido cada vez mais prevalentes e aparecem entre as principais causas de morte nessa população. Sabe-se que alterações metabólicas e nutricionais podem estar associadas ao aumento de risco CV. Assim, o objetivo deste trabalho foi avaliar o risco CV e suas associações com o estado nutricional, ingestão alimentar e o perfil metabólico em pacientes pós-TxHep. Este estudo transversal incluiu pacientes adultos pós-TxHep. Pacientes transplantados há menos de 1 ano e com histórico de insuficiência hepática fulminante, perda de enxerto hepático ou insuficiência renal crônica pós-TxHep não foram incluídos. Os pacientes passaram por avaliação clínica, nutricional e laboratorial. A avaliação nutricional compreendeu a ingestão alimentar, através de Registro Alimentar de três dias, antropometria e dinamometria. A medida da espessura da camada íntima-média carotídea (EIMC) foi avaliada por ultrassonografia Doppler e considerada alterada quando maior que 1 milímetro. Foram avaliados 69 pacientes transplantados há 2,8 (1,4 - 6,3) anos, sendo a maioria do sexo masculino (61%). Encontrou-se alta prevalência de desnutrição e sarcopenia, apresentada por 45% dos pacientes com área muscular do braço abaixo do percentil 15, e 71% com força do aperto de mão abaixo do percentil 30. Em contraste, 72% dos pacientes estavam com excesso de peso e 35% apresentaram Índice de Massa Corporal (IMC) maior que 30 kg/m2. Pacientes com EIMC alterada (54%) apresentaram maior LDL colesterol (P = 0,01), maior proporção de proteína-C reativa ultrassensível (PCR-us) maior que 1mg/L (P = 0.02) e maior ingestão de ácidos graxos saturados e trans (P = 0.01). Em conclusão, este estudo mostrou alta prevalência de EIMC alterada em uma amostra de pacientes pós-TxHep com sobrepeso e sarcopenia, associada a níveis mais elevados de LDL colesterol, PCR-us maior que 1mg/L e maior ingestão de ácidos graxos saturados e trans. Este estudo reforça que é necessário fornecer medidas preventivas, incluindo a melhoria da qualidade dietética, para todos os pacientes pós-transplante hepático, a fim de minimizar o risco CV. / In post-liver transplantation (post-LT), complications of cardiovascular (CV) disease have been increasingly prevalent and have become one of the main causes of death in this population. It is known that metabolic and nutritional imbalance may be associated with increased CV risk. Thus, the aim of this study was to evaluate CV risk and its associations with nutritional status, food intake and metabolic profile in post-LT patients. This cross-sectional study included adult post-LT patients, who underwent clinical, nutritional and laboratory evaluation. Patients who have undergone LT for less than 1 year, and with history of fulminant hepatic failure, loss of liver graft or chronic renal failure after LT were not included. The nutritional evaluation included food intake, through a three-day Food Record, anthropometry and dynamometry. The carotid intima-media thickness (CIMT) was assessed by Doppler ultrasonography and considered abnormal when greater than 1 millimeter. A total of 69 patients transplanted 2.8 (1.4 - 6.3) years ago were evaluated, being the majority male (61%). There was a high prevalence of malnutrition and sarcopenia, presented by 45% of patients with arm muscle area below the 15th percentile, and 71% with handgrip strength below the 30th percentile. In contrast, 72% of the patients were overweight and 35% had Body Mass Index greater than 30 kg/m2. Patients with altered CIMT (54%) had higher LDL cholesterol (P = 0.01), higher proportion of high-sensitive C-reactive protein (hs-CRP) greater than 1mg/L (P = 0.02) and higher intake of saturated and trans fatty acids (P = 0.01). In conclusion, this study showed a high prevalence of abnormal CIMT in a sample of post-LT patients with overweight and sarcopenia, associated with higher levels of LDL cholesterol, hs-CRP greater than 1mg/L, and higher intake of saturated and trans fatty acids. This study reinforces that it is necessary to provide preventive measures, including improvement of dietary quality, for all patients after liver transplantation, in order to minimize CV risk.
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Relationships between Mechanical Stress and Markers of Inflammation in Diseased Human Coronary ArteriesHallow, Karen Melissa 05 July 2007 (has links)
Rupture of atherosclerotic plaque is one of the primary causes of death due to cardiovascular disease. The factors directing plaque progression to instability are poorly understood. It is well-known that arteries respond to changes in mechanical stress by remodeling, and that remodeling is mediated by the inflammatory response. Studies have shown that both mechanical stress and markers of inflammation are increased in the fibrous cap and shoulder regions of plaque, where rupture most often occurs. In this study we hypothesized that there are spatial relationships between the local mechanical environment and expression of markers of inflammation in atherosclerosis, and that these relationships are plaque-progression dependent. To test these hypotheses, we analyzed cross-sections at intervals along the length of human coronary atherosclerotic arteries. For each cross-section, a heterogeneous finite element model was developed to determine the spatial distribution of stress. In addition, novel techniques for quantifying inflammatory markers at high spatial resolution were used to determine the distributions of inflammatory markers. The distributions of stress and five markers of inflammation activated NF-kB, macrophages, MMP-1, nitrotyrosine, and microvessels - were then compared to determine whether spatial relationships exists.
We demonstrated that the probability of activated NF-kB expression increases monotonically with increasing stress in all stages of plaque progression. This indicates that the relationship between mechanical stress and NF-kB activation is a player throughout the disease process. We found that the relationship between mechanical stress and macrophages is highly dependent on the state of plaque progression. In intermediate stages of progression macrophages increase with moderate stress but drop off again at very high stresses, while in the advanced stage macrophages continue to increase monotonically with stress. We found that MMP1 increases with stress in stages of progression where active remodeling is occurring, but decreases with stress in mature stable plaque. We found no relationship between mechanical stress and nitrotyrosine expression or microvessels. Taken together, these results support the role of mechanical stress in instigating and maintaining the inflammatory response, and help explain how mechanical input is able to direct the complex biological changes involved in remodeling.
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Automatic soft plaque detection from CTAArumuganainar, Ponnappan 25 August 2008 (has links)
This thesis explores two possible ways of detecting soft plaque present in the coronary arteries, using CTA imagery. The coronary arteries are vessels that supply oxidized blood to the cardiac muscle and are thus important for the proper functioning of heart. Cholesterol or reactive oxygen species from cigarette smoke and other toxins may get adhered to the walls of coronary arteries and trigger chronic inflammation that leads to formation of the soft plaque. When the soft plaque grows bigger in volume, it occludes the blood flow to the cardiac muscle and finally results in ischemic heart attack. Moreover, smaller plaque can easily rupture due to the blood flow in arteries and can result in complications such as stroke. Hence there is a need to detect the soft plaque using non-invasive or minimally invasive techniques.
In CTA imagery, the cardiac muscle appears as a dark gray color, while the blood appears as dull white color and the the calcified plaque appears as bright white. The soft plaque has an intensity which falls between the intensity level of the blood and cardiac muscle, making it difficult to directly segment the soft plaque using standard segmentation methods. Soft plaque in its advanced stages forms a concavity in the blood lumen. A watershed based segmentation method was used to detect the presence of this concavity which in turn identifies the location of the soft plaque. For segmenting the soft plaque at its earlier stages, a novel segmentation technique was used. In this technique the surface is evolved based on a region-based energy calculated in the local neighborhood around each point on the evolving surface. This method seems to be superior to the watershed based segmentation method in detecting
smaller plaque deposits.
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Perfil nutricional, metabólico e risco cardiovascular em pacientes pós-transplante hepáticoAlves, Bruna Cherubini January 2016 (has links)
No pós-transplante hepático (pós-TxHep), complicações da doença cardiovascular (CV) têm sido cada vez mais prevalentes e aparecem entre as principais causas de morte nessa população. Sabe-se que alterações metabólicas e nutricionais podem estar associadas ao aumento de risco CV. Assim, o objetivo deste trabalho foi avaliar o risco CV e suas associações com o estado nutricional, ingestão alimentar e o perfil metabólico em pacientes pós-TxHep. Este estudo transversal incluiu pacientes adultos pós-TxHep. Pacientes transplantados há menos de 1 ano e com histórico de insuficiência hepática fulminante, perda de enxerto hepático ou insuficiência renal crônica pós-TxHep não foram incluídos. Os pacientes passaram por avaliação clínica, nutricional e laboratorial. A avaliação nutricional compreendeu a ingestão alimentar, através de Registro Alimentar de três dias, antropometria e dinamometria. A medida da espessura da camada íntima-média carotídea (EIMC) foi avaliada por ultrassonografia Doppler e considerada alterada quando maior que 1 milímetro. Foram avaliados 69 pacientes transplantados há 2,8 (1,4 - 6,3) anos, sendo a maioria do sexo masculino (61%). Encontrou-se alta prevalência de desnutrição e sarcopenia, apresentada por 45% dos pacientes com área muscular do braço abaixo do percentil 15, e 71% com força do aperto de mão abaixo do percentil 30. Em contraste, 72% dos pacientes estavam com excesso de peso e 35% apresentaram Índice de Massa Corporal (IMC) maior que 30 kg/m2. Pacientes com EIMC alterada (54%) apresentaram maior LDL colesterol (P = 0,01), maior proporção de proteína-C reativa ultrassensível (PCR-us) maior que 1mg/L (P = 0.02) e maior ingestão de ácidos graxos saturados e trans (P = 0.01). Em conclusão, este estudo mostrou alta prevalência de EIMC alterada em uma amostra de pacientes pós-TxHep com sobrepeso e sarcopenia, associada a níveis mais elevados de LDL colesterol, PCR-us maior que 1mg/L e maior ingestão de ácidos graxos saturados e trans. Este estudo reforça que é necessário fornecer medidas preventivas, incluindo a melhoria da qualidade dietética, para todos os pacientes pós-transplante hepático, a fim de minimizar o risco CV. / In post-liver transplantation (post-LT), complications of cardiovascular (CV) disease have been increasingly prevalent and have become one of the main causes of death in this population. It is known that metabolic and nutritional imbalance may be associated with increased CV risk. Thus, the aim of this study was to evaluate CV risk and its associations with nutritional status, food intake and metabolic profile in post-LT patients. This cross-sectional study included adult post-LT patients, who underwent clinical, nutritional and laboratory evaluation. Patients who have undergone LT for less than 1 year, and with history of fulminant hepatic failure, loss of liver graft or chronic renal failure after LT were not included. The nutritional evaluation included food intake, through a three-day Food Record, anthropometry and dynamometry. The carotid intima-media thickness (CIMT) was assessed by Doppler ultrasonography and considered abnormal when greater than 1 millimeter. A total of 69 patients transplanted 2.8 (1.4 - 6.3) years ago were evaluated, being the majority male (61%). There was a high prevalence of malnutrition and sarcopenia, presented by 45% of patients with arm muscle area below the 15th percentile, and 71% with handgrip strength below the 30th percentile. In contrast, 72% of the patients were overweight and 35% had Body Mass Index greater than 30 kg/m2. Patients with altered CIMT (54%) had higher LDL cholesterol (P = 0.01), higher proportion of high-sensitive C-reactive protein (hs-CRP) greater than 1mg/L (P = 0.02) and higher intake of saturated and trans fatty acids (P = 0.01). In conclusion, this study showed a high prevalence of abnormal CIMT in a sample of post-LT patients with overweight and sarcopenia, associated with higher levels of LDL cholesterol, hs-CRP greater than 1mg/L, and higher intake of saturated and trans fatty acids. This study reinforces that it is necessary to provide preventive measures, including improvement of dietary quality, for all patients after liver transplantation, in order to minimize CV risk.
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Perfil nutricional, metabólico e risco cardiovascular em pacientes pós-transplante hepáticoAlves, Bruna Cherubini January 2016 (has links)
No pós-transplante hepático (pós-TxHep), complicações da doença cardiovascular (CV) têm sido cada vez mais prevalentes e aparecem entre as principais causas de morte nessa população. Sabe-se que alterações metabólicas e nutricionais podem estar associadas ao aumento de risco CV. Assim, o objetivo deste trabalho foi avaliar o risco CV e suas associações com o estado nutricional, ingestão alimentar e o perfil metabólico em pacientes pós-TxHep. Este estudo transversal incluiu pacientes adultos pós-TxHep. Pacientes transplantados há menos de 1 ano e com histórico de insuficiência hepática fulminante, perda de enxerto hepático ou insuficiência renal crônica pós-TxHep não foram incluídos. Os pacientes passaram por avaliação clínica, nutricional e laboratorial. A avaliação nutricional compreendeu a ingestão alimentar, através de Registro Alimentar de três dias, antropometria e dinamometria. A medida da espessura da camada íntima-média carotídea (EIMC) foi avaliada por ultrassonografia Doppler e considerada alterada quando maior que 1 milímetro. Foram avaliados 69 pacientes transplantados há 2,8 (1,4 - 6,3) anos, sendo a maioria do sexo masculino (61%). Encontrou-se alta prevalência de desnutrição e sarcopenia, apresentada por 45% dos pacientes com área muscular do braço abaixo do percentil 15, e 71% com força do aperto de mão abaixo do percentil 30. Em contraste, 72% dos pacientes estavam com excesso de peso e 35% apresentaram Índice de Massa Corporal (IMC) maior que 30 kg/m2. Pacientes com EIMC alterada (54%) apresentaram maior LDL colesterol (P = 0,01), maior proporção de proteína-C reativa ultrassensível (PCR-us) maior que 1mg/L (P = 0.02) e maior ingestão de ácidos graxos saturados e trans (P = 0.01). Em conclusão, este estudo mostrou alta prevalência de EIMC alterada em uma amostra de pacientes pós-TxHep com sobrepeso e sarcopenia, associada a níveis mais elevados de LDL colesterol, PCR-us maior que 1mg/L e maior ingestão de ácidos graxos saturados e trans. Este estudo reforça que é necessário fornecer medidas preventivas, incluindo a melhoria da qualidade dietética, para todos os pacientes pós-transplante hepático, a fim de minimizar o risco CV. / In post-liver transplantation (post-LT), complications of cardiovascular (CV) disease have been increasingly prevalent and have become one of the main causes of death in this population. It is known that metabolic and nutritional imbalance may be associated with increased CV risk. Thus, the aim of this study was to evaluate CV risk and its associations with nutritional status, food intake and metabolic profile in post-LT patients. This cross-sectional study included adult post-LT patients, who underwent clinical, nutritional and laboratory evaluation. Patients who have undergone LT for less than 1 year, and with history of fulminant hepatic failure, loss of liver graft or chronic renal failure after LT were not included. The nutritional evaluation included food intake, through a three-day Food Record, anthropometry and dynamometry. The carotid intima-media thickness (CIMT) was assessed by Doppler ultrasonography and considered abnormal when greater than 1 millimeter. A total of 69 patients transplanted 2.8 (1.4 - 6.3) years ago were evaluated, being the majority male (61%). There was a high prevalence of malnutrition and sarcopenia, presented by 45% of patients with arm muscle area below the 15th percentile, and 71% with handgrip strength below the 30th percentile. In contrast, 72% of the patients were overweight and 35% had Body Mass Index greater than 30 kg/m2. Patients with altered CIMT (54%) had higher LDL cholesterol (P = 0.01), higher proportion of high-sensitive C-reactive protein (hs-CRP) greater than 1mg/L (P = 0.02) and higher intake of saturated and trans fatty acids (P = 0.01). In conclusion, this study showed a high prevalence of abnormal CIMT in a sample of post-LT patients with overweight and sarcopenia, associated with higher levels of LDL cholesterol, hs-CRP greater than 1mg/L, and higher intake of saturated and trans fatty acids. This study reinforces that it is necessary to provide preventive measures, including improvement of dietary quality, for all patients after liver transplantation, in order to minimize CV risk.
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