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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.
161

Validação do instrumento para mensuração do impacto da doença no cotidiano de pacientes valvopatas

Padilha, Kátia Melissa, 1978- 24 February 2005 (has links)
Orientador: Maria Cecilia Bueno Jayme Gallani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-04T09:44:49Z (GMT). No. of bitstreams: 1 Padilha_KatiaMelissa_M.pdf: 6172357 bytes, checksum: b3712bccfb1c3bfe26b9df7e8aee7cf6 (MD5) Previous issue date: 2005 / Resumo: Este trabalho teve como objetivo verificar as propriedades psicométricas do IDCV- Instrumento para mensuração do Impacto da Doença no Cotidiano do Valvopata no que se refere a: - validade de conteúdo; validade de constructo, por meio da análise fatorial e da validade divergente correlacionando-o com o IQV - Índice de Qualidade de Vida de Ferrans e Powers; -validade de critério correlacionando-o com a Medida Geral de Impacto da Doença e com o IEQ - Questionário para Avaliação do Impacto de Doenças Crônicas; e - consistência interna. A população deste estudo foi constituída por 120 pacientes valvopatas, atendidos no Ambulatório de Cardiologia do HCIUNICAMP. Os resultados obtidos foram submetidos às análises: descritiva; análise fatorial, correlação de Pearson e alfa de Cronbach. A análise fatorial gerou quatro fatores que explicaram em 58% a variância nas respostas: 1. Impacto físico da doença (sintomas); 2.Impacto da doença nas atividades cotidianas; 3.Impacto social e emocional da doença e 4. Adaptação à doença. Houve correlação que variou de fraca a moderada magnitude entre o escore total do IDCV e de seus fatores (3 e 4) e o IQV, comprovando sua validade divergente. Verificou-se correlação de forte magnitude entre o escore total do IDCV e o IEQ, de fraca a moderada magnitude entre os fatores 1, 2 e 3 do IDCV e o IEQ e entre o escore total do IDCV e de seus fatores 2 e 3 e a Medida Geral de Impacto da Doença, comprovando sua validade de critério. Foi constatado coeficiente alfa de Cronbach = 0,74, o que evidência a consistência interna do instrumento. Os resultados do presente estudo confirmam a validade de constructo e de critério, e apontam para consistência interna do IDCV. Estudos futuros são necessários para confirmar sua confiabilidade e fornecer maiores subsídios para a melhor compreensão do significado das dimensões do impacto mensuradas pelo IDCV, bem como para avaliar a responsividade do instrumento a intervenções de saúde. Apesar das características do estudo que impedem a generalização dos resultados e ampla recomendação do uso do IDCV, pode-se afirmar que este instrumento representa um passo inicial importante nos esforços para a maior compreensão sobre a vivência com a valvopatia e a eficácia das intervenções de saúde implementadas neste contexto / Abstract: The aim of this work was to verify the psychometric properties of the IDCV -Instrument for Measuring the Impact of Illness in the Daily Life of the valve heart in terms of: -content validity construct validity, by means ofthe factorial analysis and analysis of the divergent validity correlating it with the Life Quality Index (IQV) and - criterion validity, correlating it with the General Measure of Impact of Illness and with the Illness Effects Questionnaire (IEQ) - reliability.The subjectsthis studywere 120 patients with valve heart disease, who were attended at in the Cardiology Clinic at HC/UNICAMP. Data were submitted to the following analyses: descriptive, factorial analysis, Pearson's correlation coefficient and Cronbach' s Alpha coefficient. The factorial analysis generated four factors that explained in 58% the answers variance: 1. Physical impact of the illness (symptoms); 2.Impact of illness in the daily activities; 3.Social and emotional impact of illness and 4. Adaptation to illness. Correlation ranged from weak to moderate magnitude between the IDCV total score, and its factors (3 and 4), and between IDCV and the IQV, pointing to divergent validity. Strong magnitude correlation was verified between the IDCV total score and the IEQ; weak to moderate magnitude was verified between factors 1, 2 and 3 of the IDCV and the IEQ, and among the IDCV total score (its factors 2 and 3) and General Measure of Impact of Illness to, pointing to criterion validity. It was observed a Cronbach's Alpha of 0,74, which points to the internal consistency of instrument. The results of the current study confirm the construct and criterion validity, and points to internal consistency of the IDCV. Future studies are necessary to confirm its reliability and to provide more informations for a better understanding of the meaning of the dimensions in the impact measured by the IDCV, as well as to evaluate the response ofthe instrument to health interventions. Although this study presents characteristics that do not allow the generalization of the results and a strong recommendation for using the IDCV, it can be affirmed that this instrument represents an important first step in the efforts for an understanding of the experience with the vale heart disease and the effectiveness of the health interventions implemented in this context / Mestrado / Enfermagem e Trabalho / Mestre em Enfermagem
162

Barlow’s Mitral Valve Disease: A Comparison of Neochordal (Loop) and Edge-To-Edge (Alfieri) Minimally Invasive Repair Techniques

da Rocha e Silva, Jaqueline Grace 08 December 2015 (has links)
Background. Barlow’s mitral valve (MV) disease re- mains a surgical challenge. We compared short- and medium-term outcomes of neochordal (“loop”) versus edge-to-edge (“Alfieri”) minimally invasive MV repair in patients with Barlow’s disease. Methods. From January 2009 to April 2014, 123 consecutive patients with Barlow’s disease (defined as bileaflet billowing or prolapse [or both], excessive leaflet tissue, and annular dilatation with or without calcifica- tion) underwent minimally invasive MV operations for severe mitral regurgitation (MR) at our institution. Three patients (2.4%) underwent MV replacement during the study period and were excluded from subsequent anal- ysis. The loop MV repair technique was used in 68 pa- tients (55.3%) and an edge-to-edge repair was performed in 44 patients (35.8%). Patients who underwent a combi- nation of these 2 techniques (n [ 8 [6.5%]) were excluded. The median age was 48 years, and 62.5% of patients were men. Concomitant procedures included closure of a patent foramen ovale or atrial septal defect (n [ 19), tricuspid valve repair (n [ 5), and atrial fibril- lation ablation (n [ 15). Follow-up was performed 24.7 ± 17 months postoperatively and was 98% complete. Results. No deaths occurred perioperatively or during follow-up. Aortic cross-clamp time (64.1 ± 17.6 minutes versus 95.9 ± 29.5 minutes) and cardiopulmonary bypass (CPB) time (110.0 ± 24.2 minutes versus 146.4 ± 39.1 mi- nutes) were significantly shorter (p < 0.001) in patients who received edge-to-edge repair. Although patients who underwent edge-to-edge repair received a larger annulo- plasty ring (38.6 ± 1.5 mm versus 35.8 ± 2.7 mm; p < 0.001), the early postoperative resting mean gradients were higher(3.3±1.2mmHgversus2.6±1.2mmHg;p[ 0.007) and the mitral orifice area tended to be smaller in this group (2.8 ± 0.7 cm2 versus 3.0 ± 0.7 cm2; p [ 0.06). The amount of residual MR was similar between groups (0.3 ± 0.6 versus 0.6 ± 1.0 for edge-to-edge versus loop procedures, respectively; p [ 0.08). More than mild MR requiring early MV reoperation was present in 3 patients who underwent loop procedures (4.4%) and in no patients who had edge-to-edge procedures (p [ 0.51). During follow-up, 2 patients (1 in each group) required MV replacement for severe MR. The 4-year freedom from MV reoperation was 92.8% ± 5.0% in the Alfieri group compared with 90.9% ± 4.6% in the loop group (p [ 0.94). Conclusions. Minimally invasive MV repair can be accomplished with excellent early and medium-term outcomes in patients with Barlow’s disease. The edge- to-edge (Alfieri) repair can be performed with reduced operative times when compared with the loop technique, but it results in mildly increased transvalvular gradients and mildly decreased valve opening areas without any difference in residual MR.
163

Prädiktion der linksventrikulären Funktion nach Mitralklappenrekonstruktion unter Verwendung des präoperativen Tei Index

Gröger, Steffen 19 April 2016 (has links)
Die chirurgische Mitralklappenrekonstruktion (MKR) ist der konservativen Therapie bei signifikanter Mitralklappeninsuffizienz (MI) überlegen. Bisher fehlen sensitive präoperative Parameter zur Detektion latenter linksventrikulärer Funktionsstörungen. Aufgrund der pathophysiologisch bedingten Nachlastreduktion und Vorlaststeigerung bei MI bergen die konventionell verwendeten Ejektionsindices, Ejektionsfraktion (EF) und Fractional Area Change (FAC), die Gefahr der Überschätzung der effektiven Pumpfunktion des linken Ventrikels (LV). Der dopplersonographisch erhobene Tei Index gilt als ein Marker globaler myokardialer Funktion. Ziel der vorliegenden Studie war es, mit dem Tei Index (bzw. dem Myokardialen Performance Index, MPI) einen sensitiveren präoperativen Parameter zur Prädiktion der postoperativen linksventrikulären Funktion zu finden. Hierzu wurden im Rahmen einer prospektiven klinischen Studie 130 Patienten mit signifikanter MI am Herzzentrum Leipzig entsprechend den ASE/SCA Leitlinien vor und nach kardiopulmonaler Bypass-Operation mittels transösophagealer echokardiographischer (TEE) Bildgebung untersucht. Die Quantifizierung der MI erfolgte durch Messung der Vena contracta (VC). Die FAC wurde in der transgastrischen midpapillären kurzen Achse und die EF im midösophagealen Zwei- sowie Vier-Kammer-Blick erfasst. Die Zeitintervalle zur Berechnung des Tei Index wurden im tiefen transgastrischen und midösophagealen Vier-Kammer-Blick erfasst. Eine statistische Korrelation zwischen präoperativen Tei Index und postoperativer EF und FAC konnte zur Validierung unserer Hypothese nicht detektiert werden. Folgend kann der Tei Index nicht als Prädiktor der effektiven linksventrikulären Funktion vor MKR gewertet werden.
164

"Avaliação dos resultados a médio prazo da ablação cirúrgica por radiofreqüência da fibrilação atrial permanente em pacientes portadores de valvopatia mitral reumática" / Mid-term results of the maze procedure using radiofrequency ablation in patients with permanent atrial fibrillation and rheumatic mitral valve disease

Abreu Filho, Carlos Alberto Cordeiro de 21 June 2005 (has links)
A ablação cirúrgica por radiofreqüência (RF) é uma nova técnica para tratar a fibrilação atrial (FA) permanente. O objetivo deste estudo é avaliar a eficácia da ablação cirúrgica por RF da FA permanente em pacientes com valvopatia mitral reumática (VMR). Entre Fevereiro de 2002 e Abril de 2003, 70 pacientes com FA permanente e VMR foram submetidos à operação da valva mitral associada à ablação por RF da FA (Grupo A); ou à operação da valva mitral isolada (Grupo B). No seguimento pós-operatório foram avaliados: a reversão para o ritmo sinusal (RS) e a contratilidade atrial. Após 12 meses de seguimento, os índices de reversão para o RS e de restabelecimento da contratilidade atrial foram significativamente superiores no Grupo A. A ablação cirúrgica por RF é eficaz para o tratamento da FA permanente em pacientes com VMR / Radiofrequency ablation is a new surgical technique to treat permanent atrial fibrillation. The aim of this study was to evaluate the effectiveness of the (RF) ablation for the treatment of permanent AF in patients with rheumatic mitral valve (MV) disease. Between February 2002 and April 2003, 70 patients with permanent AF and rheumatic MV disease were assigned to undergo a MV surgery associated with RF ablation (Group A), or MV surgery alone (Group B). After 12 months of follow-up, the cumulative rates of sinus rhythm conversion and atrial transport function restoration were higher in Group A.The RF ablation is effective for treating permanent AF associated with rheumatic MV disease
165

"Avaliação dos resultados a médio prazo da ablação cirúrgica por radiofreqüência da fibrilação atrial permanente em pacientes portadores de valvopatia mitral reumática" / Mid-term results of the maze procedure using radiofrequency ablation in patients with permanent atrial fibrillation and rheumatic mitral valve disease

Carlos Alberto Cordeiro de Abreu Filho 21 June 2005 (has links)
A ablação cirúrgica por radiofreqüência (RF) é uma nova técnica para tratar a fibrilação atrial (FA) permanente. O objetivo deste estudo é avaliar a eficácia da ablação cirúrgica por RF da FA permanente em pacientes com valvopatia mitral reumática (VMR). Entre Fevereiro de 2002 e Abril de 2003, 70 pacientes com FA permanente e VMR foram submetidos à operação da valva mitral associada à ablação por RF da FA (Grupo A); ou à operação da valva mitral isolada (Grupo B). No seguimento pós-operatório foram avaliados: a reversão para o ritmo sinusal (RS) e a contratilidade atrial. Após 12 meses de seguimento, os índices de reversão para o RS e de restabelecimento da contratilidade atrial foram significativamente superiores no Grupo A. A ablação cirúrgica por RF é eficaz para o tratamento da FA permanente em pacientes com VMR / Radiofrequency ablation is a new surgical technique to treat permanent atrial fibrillation. The aim of this study was to evaluate the effectiveness of the (RF) ablation for the treatment of permanent AF in patients with rheumatic mitral valve (MV) disease. Between February 2002 and April 2003, 70 patients with permanent AF and rheumatic MV disease were assigned to undergo a MV surgery associated with RF ablation (Group A), or MV surgery alone (Group B). After 12 months of follow-up, the cumulative rates of sinus rhythm conversion and atrial transport function restoration were higher in Group A.The RF ablation is effective for treating permanent AF associated with rheumatic MV disease
166

Cost-effectiveness of Transcatheter Mitral Valve Leaflet Repair for the Treatment of Mitral Regurgitation in Heart Failure

Asgar, Anita W. 04 1900 (has links)
Contexte: La régurgitation mitrale (RM) est une maladie valvulaire nécessitant une intervention dans les cas les plus grave. Une réparation percutanée de la valve mitrale avec le dispositif MitraClip est un traitement sécuritaire et efficace pour les patients à haut risque chirurgical. Nous voulons évaluer les résultats cliniques et l'impact économique de cette thérapie par rapport à la gestion médicale des patients en insuffisance cardiaque avec insuffisance mitrale symptomatique. Méthodes: L'étude a été composée de deux phases; une étude d'observation de patients souffrant d'insuffisance cardiaque et de régurgitation mitrale traitée avec une thérapie médicale ou le MitraClip, et un modèle économique. Les résultats de l'étude observationnelle ont été utilisés pour estimer les paramètres du modèle de décision, qui a estimé les coûts et les avantages d'une cohorte hypothétique de patients atteints d'insuffisance cardiaque et insuffisance mitrale sévère traitée avec soit un traitement médical standard ou MitraClip. Résultats: La cohorte de patients traités avec le système MitraClip était appariée par score de propension à une population de patients atteints d'insuffisance cardiaque, et leurs résultats ont été comparés. Avec un suivi moyen de 22 mois, la mortalité était de 21% dans la cohorte MitraClip et de 42% dans la cohorte de gestion médicale (p = 0,007). Le modèle de décision a démontré que MitraClip augmente l'espérance de vie de 1,87 à 3,60 années et des années de vie pondérées par la qualité (QALY) de 1,13 à 2,76 ans. Le coût marginal était 52.500 $ dollars canadiens, correspondant à un rapport coût-efficacité différentiel (RCED) de 32,300.00 $ par QALY gagné. Les résultats étaient sensibles à l'avantage de survie. Conclusion: Dans cette cohorte de patients atteints d'insuffisance cardiaque symptomatique et d insuffisance mitrale significative, la thérapie avec le MitraClip est associée à une survie supérieure et est rentable par rapport au traitement médical. / Background: Mitral regurgitation (MR) is a common valvular heart disorder requiring intervention once it becomes severe. Transcatheter mitral valve leaflet repair with the MitraClip device is a safe and effective therapy for selected patients denied surgery. We sought to evaluate the clinical outcomes and economic impact of this therapy compared to medical management in heart failure patients with symptomatic MR. Methods: The study was comprised of two phases; an observational study of patients with heart failure and MR treated with either medical therapy or the MitraClip, and an economic model. Results of the observational study were used to estimate parameters for the decision model, which estimated costs, and benefits in a hypothetical cohort of patients with heart failure and moderate to severe MR treated with either standard medical therapy or MitraClip. Results: The cohort of patients treated with the MitraClip was propensity matched to a population of heart failure patients, and their outcomes compared. At a mean follow up of 22 months, all-cause mortality was 21% in the MitraClip cohort and 42% in the medical management cohort (p=0.007). The decision model demonstrated that MitraClip increased life expectancy from 1.87 to 3.60 years and quality-adjusted life years (QALY) from 1.13 to 2.76 years. The incremental cost was $52,500 Canadian dollars, corresponding to an incremental cost-effectiveness ratio (ICER) of $32,300.00 per QALY gained. Results were sensitive to the survival benefit. Conclusion: In this cohort of heart failure patients with symptomatic moderate-severe MR, therapy with the MitraClip was associated with superior survival and is cost-effective compared to medical therapy.
167

Efeito do tratamento com benazepril e carvedilol administrado de forma isolada e em associação com treinamento físico supervisionado sobre a evolução clínica de cães com insuficiência mitral crônica naturalmente adquirida / Effect of benazepril and carvedilol treatment alone and in association with a supervised physical training in the development of naturally acquired chronic mitral valve regurgitation in dogs

Santos, Mario Marcondes dos 21 November 2007 (has links)
INTRODUÇÃO: Pacientes com insuficiência mitral crônica apresentam aumento da atividade simpática mesmo quando assintomáticos. Contudo, pouco se sabe sobre o efeito de drogas beta bloqueadoras ou de um programa de treinamento físico supervisionado como moduladores desta atividade simpática durante a evolução da doença. O objetivo deste estudo foi avaliar o efeito do carvedilol e de um programa de treinamento físico aeróbico regular sobre a evolução da insuficiência mitral crônica num modelo da doença em cães. Além disso, objetivou-se analisar as principais variáveis que atuam como preditoras de óbito. MÉTODOS: Foram selecionados 10 cães hígidos para padronização dos parâmetros normais. Outros 36 cães com diagnóstico de insuficiência mitral crônica foram divididos em 3 subgrupos (I, II e III). Do início do estudo (T0) até os 6 meses (T2), todos receberam tratamento clínico convencional (benazepril e digoxina, codeína, diurético quando necessário), sendo que no II (n=10) e III (n=13) associou-se o carvedilol durante todo o período, e no I (n=13) e II, após os 3 meses iniciais (T1), associou-se o treinamento físico supervisionado. As principais variáveis clínicas (número de intercorrências, peso, qualidade de vida avaliada pelo questionário FETCH, freqüência e ritmo cardíacos, classe funcional de insuficiência cardíaca e pressão arterial sistólica e diastólica); laboratoriais (norepinefrina, troponina I, sódio, uréia e creatinina) e ecodopplercardiográficas foram avaliadas. RESULTADOS: Não houve diferença de sobrevida entre os 3 subgrupos. Em relação às variáveis clínicas, observou-se melhora da qualidade de vida (FETCH) nos três subgrupos: I (T0= 5,56±4,67 vs T2=2,67±3,12; p<0,05), II (T0= 11,29±5,12 vs T2= 3± 3,32; p,0,05); III (T0= 15,50±9,94 vs T1=5 ±3,21 e T0 vs T2=4,25± 2,82; p<0,05). Quanto à freqüência cardíaca (em bpm) observaram-se diferenças (p=0,023) nos subgrupos: I (T0=139,44±22,97 vs T2=126,67±12,25), II (T0=128,57±31,32 vs T2=117,14± 25,63) e III (T0=142,50±53,39 vs T2=117,75±28,92). As demais variáveis clínicas, laboratoriais e ecodopplercardiográficas não apresentaram alterações. O grupo de animais que vieram a óbito apresentaram valores maiores para algumas variáveis em relação ao grupo não óbito, a saber: FETCH (23,67±9,66 vs 10,54±7,93; p<0,001), norepinefrina (684±378,12 vs 456,54±439,16 pg/ml; p=0,018) , troponina I (0,37 ±0,39 vs 0,09±0,14 ng/ml; p=0,007), freqüência cardíaca (158,33 ±22,5 vs 137,29 ±36,62 bpm; p=0,041), diâmetro diastólico (4,06±1,26 vs 3,06±0,78 cm; p=0,024) e sistólico (2,19± 0,84 vs 1,60±0,51 cm; p= 0,041) ventricular esquerdo e relação do diâmetro atrial esquerdo pela raiz da aorta (2,04± 0,39 vs 1,52±0,25; p<0,001) , além de ser composto majoritariamente por machos, em classe funcional III-IV e com ritmo cardíaco simpático. Foram selecionadas como preditores de óbito as variáveis: relação do diâmetro atrial esquerdo pela raiz da aorta, FETCH e ritmo cardíaco simpático. CONCLUSÕES: A associação do carvedilol e do programa de treinamento físico supervisionado ao tratamento convencional promoveu melhora da qualidade de vida e diminuição da FC mas não melhorou a sobrevida dos cães avaliados. As variáveis selecionadas como preditores de óbito foram: relação do diâmetro atrial esquerdo pela raiz da aorta, FETCH e ritmo cardíaco simpático. / INTRODUCTION: Sympathetic activation is present in patients having chronic mitral valve regurgitation even in asymptomatic ones. However, the effect of beta- blockers and a physical training program to modulate this sympathetic activation during this valve disease is unknown. The objective of this study has been to evaluate the effect of carvedilol and a physical aerobic training in the development of chronic mitral valve regurgitation in an experimental model of the disease in dogs. Moreover, the objective sought for some death predict variables in these dogs. METHODS: 10 healthy dogs were selected to evaluate the normal parameters. The other 36 chronic valve mitral regurgitation dogs were divided into 3 sub-groups (I, II e III). From the beginning of the study (T0) to 6 months (T2) all of them received the conventional treatment (Benazepril and Digoxine, codeine, diuretic when necessary). In the sub-group II (n=10) and III (n=13) the carvedilol was added to the treatment during all the study. In the sub-group I (n=13) and II, after the first 3 months (T1) the physical supervised training was added. The main clinical variables (number of interoccurrences, body weight, quality of life estimated by FETCH questionnaire, heart rate, cardiac rhythm, functional classification of heart failure, systolic and diastolic blood pressure), laboratory variables (norepinephrine, troponin I, sodium, urea, creatinine) and echodopplercardiographic variables were evaluated. RESULTS: The analyzes of the clinic variables showed an improvement in the quality of life (FETCH) in all the sub-groups: (T0= 5,56±4,67 vs T2=2,67±3,12; p<0,05), II (T0= 11,29±5,12 vs T2= 3± 3,32; p,0,05); III (T0= 15,50±9,94 vs T1=5 ±3,21 e T0 vs T2=4,25± 2,82; p<0,05). The heart rate (beats/min) results showed differences (p=0,023) in the sub-groups I (T0=139,44±22,97 vs T2=126,67±12,25), II (T0=128,57±31,32 vs T2=117,14± 25,63) and III (T0=142,50±53,39 vs T2=117,75±28,92). However, the other clinic, laboratory and echodopplercardiographic variables did not show any differences. The group of animals that died in comparison with the survivor group showed high values in some variables, as follows: FETCH (23,67±9,66 vs 10,54±7,93; p<0,001), norepinephrine (684±378,12 vs 456,54±439,16 pg/ml; p=0,018) , troponin I (0,37 ±0,39 vs 0,09±0,14 ng/ml; p=0,007), heart rate (158,33 ±22,5 vs 137,29 ±36,62 beats/min; p=0,041), diastolic left ventricular dimension (4,06±1,26 vs 3,06±0,78 cm; p=0,024), systolic left ventricular dimension (2,19± 0,84 vs 1,60±0,51 cm; p= 0,041) and left atrium to aortic root ratio (2,04± 0,39 vs 1,52±0,25; p<0,001). The death group in its majority comprehended male dogs in functional classification III-IV having sympathetic cardiac rhythm. The selected death predict variables were: left atrium to aortic root ratio, FETCH and sympathetic cardiac rhythm. CONCLUSION: The association of carvedilol as well as supervised physical training with the conventional treatment in dogs having chronic mitral valve regurgitation provided the improvement in quality of life but not in survival time and a decrease in the heart rate. The selected death predict variables were: left atrium to aortic root ratio, FETCH and sympathetic cardiac rhythm.
168

The fluid shear stress environment of the normal and congenital bicuspid aortic valve and the implications on valve calcification

Yap, Choon Hwai 18 August 2011 (has links)
Calcific aortic valve disease is highly prevalent, especially in the elderly. Currently, the exact mechanism of the calcification process is not completely understood, limiting our ability to prevent or cure the disease. Ex vivo investigations, however, have provided evidence that the aortic valve's biological response is sensitive to mechanical forces, including fluid shear stresses, leading to the hypothesis that adverse fluid shear stress environment play a role in leading to valve calcification. This thesis seeks to investigate this hypothesis. A method for performing experimental measurement of time-varying shear stress on aortic valve leaflets under physiologic flow conditions was first developed, based on the Laser Doppler Velocimetry technique, and was systematically validated. This method was then applied to both the aortic surface and the ventricular surface of a normal tricuspid the aortic valve, and then on a congenital bicuspid aortic valve, using suitable in vitro valve models and an in vitro pulsatile flow loop. It was found that in the tricuspid valve, the peak shear stress on the aortic surface under adult resting condition was approximately 15-19 dyn/cm². Aortic surface shear stresses were elevated during mid- to late-systole, with the development of the sinus vortex, and were low during all other instances. Aortic surface shear stresses were observed to increase with increasing stroke volume and with decreasing heart rate. On the ventricular surface, shear stresses had a systolic peak of approximately 64-71 dyn/cm² under adult resting conditions. During late systole, due to the Womersley effect, shear stresses were observed to reverse in direction to a substantial magnitude for a substantial period of time. Further, it was found that a moderately stenotic bicuspid aortic valve can experience excessive unsteadiness in shear stress experienced by its leaflets, most likely due to the turbulent forward flow resulting from the stenosis, and due to the skewed forward flow. To demonstrate that the measured shear stresses can have an effect on the aortic valve biology, ex vivo experiments were performed in specific to determine the effects of these various shear stress characteristics on the biological response of porcine aortic valve leaflets, using the cone and plate bioreactor. It was found that unsteady shear stress measured in the bicuspid valve resulted in increased calcium accumulation. Further, it was found that low shear stresses and high frequency shear stresses resulted in increased calcium accumulation. Thus, shear stress was found to affect aortic valve pathology, and low and unsteady fluid shear stresses can enhance pathology.
169

Efeito do tratamento com benazepril e carvedilol administrado de forma isolada e em associação com treinamento físico supervisionado sobre a evolução clínica de cães com insuficiência mitral crônica naturalmente adquirida / Effect of benazepril and carvedilol treatment alone and in association with a supervised physical training in the development of naturally acquired chronic mitral valve regurgitation in dogs

Mario Marcondes dos Santos 21 November 2007 (has links)
INTRODUÇÃO: Pacientes com insuficiência mitral crônica apresentam aumento da atividade simpática mesmo quando assintomáticos. Contudo, pouco se sabe sobre o efeito de drogas beta bloqueadoras ou de um programa de treinamento físico supervisionado como moduladores desta atividade simpática durante a evolução da doença. O objetivo deste estudo foi avaliar o efeito do carvedilol e de um programa de treinamento físico aeróbico regular sobre a evolução da insuficiência mitral crônica num modelo da doença em cães. Além disso, objetivou-se analisar as principais variáveis que atuam como preditoras de óbito. MÉTODOS: Foram selecionados 10 cães hígidos para padronização dos parâmetros normais. Outros 36 cães com diagnóstico de insuficiência mitral crônica foram divididos em 3 subgrupos (I, II e III). Do início do estudo (T0) até os 6 meses (T2), todos receberam tratamento clínico convencional (benazepril e digoxina, codeína, diurético quando necessário), sendo que no II (n=10) e III (n=13) associou-se o carvedilol durante todo o período, e no I (n=13) e II, após os 3 meses iniciais (T1), associou-se o treinamento físico supervisionado. As principais variáveis clínicas (número de intercorrências, peso, qualidade de vida avaliada pelo questionário FETCH, freqüência e ritmo cardíacos, classe funcional de insuficiência cardíaca e pressão arterial sistólica e diastólica); laboratoriais (norepinefrina, troponina I, sódio, uréia e creatinina) e ecodopplercardiográficas foram avaliadas. RESULTADOS: Não houve diferença de sobrevida entre os 3 subgrupos. Em relação às variáveis clínicas, observou-se melhora da qualidade de vida (FETCH) nos três subgrupos: I (T0= 5,56±4,67 vs T2=2,67±3,12; p<0,05), II (T0= 11,29±5,12 vs T2= 3± 3,32; p,0,05); III (T0= 15,50±9,94 vs T1=5 ±3,21 e T0 vs T2=4,25± 2,82; p<0,05). Quanto à freqüência cardíaca (em bpm) observaram-se diferenças (p=0,023) nos subgrupos: I (T0=139,44±22,97 vs T2=126,67±12,25), II (T0=128,57±31,32 vs T2=117,14± 25,63) e III (T0=142,50±53,39 vs T2=117,75±28,92). As demais variáveis clínicas, laboratoriais e ecodopplercardiográficas não apresentaram alterações. O grupo de animais que vieram a óbito apresentaram valores maiores para algumas variáveis em relação ao grupo não óbito, a saber: FETCH (23,67±9,66 vs 10,54±7,93; p<0,001), norepinefrina (684±378,12 vs 456,54±439,16 pg/ml; p=0,018) , troponina I (0,37 ±0,39 vs 0,09±0,14 ng/ml; p=0,007), freqüência cardíaca (158,33 ±22,5 vs 137,29 ±36,62 bpm; p=0,041), diâmetro diastólico (4,06±1,26 vs 3,06±0,78 cm; p=0,024) e sistólico (2,19± 0,84 vs 1,60±0,51 cm; p= 0,041) ventricular esquerdo e relação do diâmetro atrial esquerdo pela raiz da aorta (2,04± 0,39 vs 1,52±0,25; p<0,001) , além de ser composto majoritariamente por machos, em classe funcional III-IV e com ritmo cardíaco simpático. Foram selecionadas como preditores de óbito as variáveis: relação do diâmetro atrial esquerdo pela raiz da aorta, FETCH e ritmo cardíaco simpático. CONCLUSÕES: A associação do carvedilol e do programa de treinamento físico supervisionado ao tratamento convencional promoveu melhora da qualidade de vida e diminuição da FC mas não melhorou a sobrevida dos cães avaliados. As variáveis selecionadas como preditores de óbito foram: relação do diâmetro atrial esquerdo pela raiz da aorta, FETCH e ritmo cardíaco simpático. / INTRODUCTION: Sympathetic activation is present in patients having chronic mitral valve regurgitation even in asymptomatic ones. However, the effect of beta- blockers and a physical training program to modulate this sympathetic activation during this valve disease is unknown. The objective of this study has been to evaluate the effect of carvedilol and a physical aerobic training in the development of chronic mitral valve regurgitation in an experimental model of the disease in dogs. Moreover, the objective sought for some death predict variables in these dogs. METHODS: 10 healthy dogs were selected to evaluate the normal parameters. The other 36 chronic valve mitral regurgitation dogs were divided into 3 sub-groups (I, II e III). From the beginning of the study (T0) to 6 months (T2) all of them received the conventional treatment (Benazepril and Digoxine, codeine, diuretic when necessary). In the sub-group II (n=10) and III (n=13) the carvedilol was added to the treatment during all the study. In the sub-group I (n=13) and II, after the first 3 months (T1) the physical supervised training was added. The main clinical variables (number of interoccurrences, body weight, quality of life estimated by FETCH questionnaire, heart rate, cardiac rhythm, functional classification of heart failure, systolic and diastolic blood pressure), laboratory variables (norepinephrine, troponin I, sodium, urea, creatinine) and echodopplercardiographic variables were evaluated. RESULTS: The analyzes of the clinic variables showed an improvement in the quality of life (FETCH) in all the sub-groups: (T0= 5,56±4,67 vs T2=2,67±3,12; p<0,05), II (T0= 11,29±5,12 vs T2= 3± 3,32; p,0,05); III (T0= 15,50±9,94 vs T1=5 ±3,21 e T0 vs T2=4,25± 2,82; p<0,05). The heart rate (beats/min) results showed differences (p=0,023) in the sub-groups I (T0=139,44±22,97 vs T2=126,67±12,25), II (T0=128,57±31,32 vs T2=117,14± 25,63) and III (T0=142,50±53,39 vs T2=117,75±28,92). However, the other clinic, laboratory and echodopplercardiographic variables did not show any differences. The group of animals that died in comparison with the survivor group showed high values in some variables, as follows: FETCH (23,67±9,66 vs 10,54±7,93; p<0,001), norepinephrine (684±378,12 vs 456,54±439,16 pg/ml; p=0,018) , troponin I (0,37 ±0,39 vs 0,09±0,14 ng/ml; p=0,007), heart rate (158,33 ±22,5 vs 137,29 ±36,62 beats/min; p=0,041), diastolic left ventricular dimension (4,06±1,26 vs 3,06±0,78 cm; p=0,024), systolic left ventricular dimension (2,19± 0,84 vs 1,60±0,51 cm; p= 0,041) and left atrium to aortic root ratio (2,04± 0,39 vs 1,52±0,25; p<0,001). The death group in its majority comprehended male dogs in functional classification III-IV having sympathetic cardiac rhythm. The selected death predict variables were: left atrium to aortic root ratio, FETCH and sympathetic cardiac rhythm. CONCLUSION: The association of carvedilol as well as supervised physical training with the conventional treatment in dogs having chronic mitral valve regurgitation provided the improvement in quality of life but not in survival time and a decrease in the heart rate. The selected death predict variables were: left atrium to aortic root ratio, FETCH and sympathetic cardiac rhythm.
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Cardiopatia reumática com lesão valvar em crianças e adolescentes: fatores associados ao tempo até a terapêutica cirúrgica

Müller, Regina Elizabeth January 2011 (has links)
Made available in DSpace on 2014-07-22T13:16:48Z (GMT). No. of bitstreams: 2 Regina Elizabeth Müller.pdf: 4161979 bytes, checksum: 5df884fdb04b617145c35c1741e9b502 (MD5) license.txt: 1914 bytes, checksum: 7d48279ffeed55da8dfe2f8e81f3b81f (MD5) Previous issue date: 2011 / Fundação Oswaldo Cruz. Instituto Nacional de Saúde da Mulher, da Criança e do Adolescente Fernandes Figueira. Rio de Janeiro, RJ, Brasil. / Introdução: A cardiopatia reumática persiste como a principal doença cardiovascular adquirida em crianças e adultos jovens em todo o mundo, sendo responsável por altas taxas de morbimortalidade e evoluindo com frequência para a necessidade de cirurgia cardíaca valvar em pacientes na fase aguda ou crônica da doença. Objetivo: Estimar os fatores associados e o tempo desde o diagnóstico até a cirurgia cardíaca valvar em crianças e adolescentes portadores de cardiopatia reumática, em um centro cardiológico de referência terciária no Rio de Janeiro. Material e Métodos: estudo observacional longitudinal de base hospitalar, utilizando metodologia de análise de sobrevivência, para estimativa do tempo até a cirurgia, e modelo de regressão de Cox, para avaliar as razões de risco associadas segundo as covariáveis. A coorte foi composta por pacientes com 3 a 20 anos, cadastrados no Instituto Nacional de Cardiologia no Rio de Janeiro entre julho de 1986 e junho de 2006 e acompanhados até setembro de 2011. O diagnóstico da lesão valvar foi confirmado pelo exame Doppler-ecocardiográfico. As covariáveis, avaliadas no início do acompanhamento, foram reunidas em três dimensões: sociodemográfica (sexo, grupo etário, cor da pele, região de moradia e década do diagnóstico); clínica (apresentação clínica, classe funcional, número de surtos anteriores, profilaxia secundária, endocardite infecciosa e fibrilação atrial); e ecocardiográfica (lesão valvar por tipo e gravidade; diâmetro do átrio esquerdo, diâmetro sistólico do ventrículo esquerdo, função ventricular esquerda, hipertensão arterial pulmonar, e ruptura de cordoalha mitral). O banco de dados foi elaborado com o programa ACCESS 2000 e a análise estatística foi realizada pelo programa R versão 2.13.1. Foi considerado significativo o valor de - 0,05. Resultados: a coorte foi composta por 348 pacientes, 58% do sexo feminino, com idade mediana ao cadastro de 12,5 anos, e de 21,5 anos ao final do acompanhamento. O tempo médio de seguimento foi de 9,0 anos (2-21 anos). O evento cirurgia cardíaca ocorreu em 39% da amostra, com tempo mediano até a cirurgia de 22,3 anos. Na análise univariada todas as covariáveis das três dimensões (socioedemográfica, clínica e ecocardiográfica) apresentaram significância estatística e risco para realização de cirurgia cardíaca (hazard ratio>1), com exceção apenas da covariável região de moradia (p>0,5). Na análise multivariada, o modelo final incluiu as variáveis: década do diagnóstico, classe funcional, número de surtos anteriores, endocardite infecciosa, lesão valvar por tipo e gravidade, diâmetro do átrio esquerdo, diâmetro sistólico do ventrículo esquerdo e ruptura de cordoalha mitral. Conclusões: A realização da cirurgia cardíaca em pacientes com cardiopatia reumática está associada a fatores sociodemográficos, clínicos e ecocardiográficos. / Introduction: Rheumatic heart disease remains as the most common acquired heart disease in children and young adults all over the world, being responsible for high mortality and morbidity rates and often demanding valve surgery in the acute or chronic phase of the disease. Objective: To estimate the time from diagnosis until valve operation and the associated factors in children and young adults with rheumatic heart disease followed up in a tertiary center for cardiovascular care in Rio de Janeiro. Methods – It is a longitudinal observational study of a hospital based population, using survival analysis methodology for time estimation and Cox regression model for hazard risk evaluation of associated variables. Cohort was composed by 3 to 20 years old patients, registered in the National Institute of Cardiology (Instituto Nacional de Cardiologia), in Rio de Janeiro, between July 1986 and June 2006, and followed up until September 2011. Valve disease diagnosis was confirmed through Doppler echocardiography examination. Variables were evaluated at the patient´s first visit and separated in three dimensions: socio demographic (gender, age group, skin color, residence region, decade of diagnosis); clinic (disease status at presentation, functional class, number of previous rheumatic episodes, secondary prophylaxis, infectious endocarditis, atrial fibrillation); echocardiographic (valve lesion and severity, left atrium diameter, systolic left ventricle diameter, left ventricle function, pulmonary hypertension, rupture of mitral chordae). The database wasbased on the program ACCESS 2000 and statistical analysis was performed using the R Program version 2.13.1. For statistical analysis was considered as significant values for  value 0.05. Results – 348 patients were included in the cohort, 58% female. Median age at the register was 12.5 years, and 21.5 years at the end of follow up. Median follow-up time was 9.0 years (2 to 21 years). 39% underwent valve operation and the median time until surgery was 22.3 years. In the univariate analysis all the variables from the three dimensions (socio demographic, clinic and echocardiographic) presented statistical significance as hazard risk in predicting valve operation (hazard ratio>1), with only one exception, that was residence region (p>0.5). In the multivariate analysis the final model included the following variables: decade of diagnosis, functional class, number of anterior rheumatic episodes, infectious endocarditis, valve lesion and severity, left atrium diameter, systolic left ventricle diameter and rupture of mitral chordate. Conclusions: Valve surgery in patients with rheumatic heart disease is associated with socio demographic, clinic and echocardiographic factors.

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