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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.
1

Carotid artery longitudinal wall motion: Regulatory factors and implications for arterial health

Au, Jason S 11 1900 (has links)
The carotid artery wall moves longitudinally along the length of the vessel, although little is known about what causes this motion, or what health information it represents. The overarching purpose of this dissertation was to investigate the regulation of carotid artery longitudinal wall motion (CALM) in humans, as well as how CALM can be used to infer information about arterial health. Through observational and experimental designs, we tested evidence for a structural ventricular-vascular coupling effect, which postulates that systolic anterograde CALM is influenced by the forward blood shear rate while systolic retrograde CALM is influenced by left ventricular rotation, although the data suggests a moderate influence of left ventricular rotation, and minimal influence of shear rate. In cross-sectional analyses, we demonstrated that diastolic CALM variables are better related to age and health status compared to systolic CALM displacement and that this relationship was independent of traditional measures of arterial stiffness. These experimental and observational results directed the use of diastolic CALM as a potential indicator of arterial health in subsequent studies, due to the relative independence from systolic events. While there was no effect of 12-weeks of exercise training in healthy men on diastolic CALM variables, we observed increased systolic retrograde CALM and diastolic CALM acceleration in men with a history of resistance exercise training compared to sedentary men, suggesting an effect of habitual exercise training. Our novel findings suggest that CALM is regulated by a complex system, in part related to both arterial wall structure and ventricular-vascular coupling, and may have clinical value in complimenting measures of traditional arterial stiffness in humans. Future studies should examine whether local changes to arterial wall structure or indirect changes in regulatory control dictate differences in CALM with aging and with chronic exercise training, before integrating CALM into routine measurement of arterial health. / Thesis / Doctor of Philosophy (PhD) / We have known for a long time that arteries expand in order to absorb pressure; however, only recently have we identified that arteries also move longitudinally along the length of the arterial wall. The overarching purpose of this dissertation was to study what causes carotid artery longitudinal wall motion (CALM), and how we can use this information to understand arterial health. We demonstrated that CALM is partly controlled through the forward blood velocity wave and left ventricular rotation of the heart, and that diastolic CALM is uniquely related to aging and health status, but is not impacted by exercise training in healthy men. There are many aspects of CALM that need to be examined before wide-spread use, though our results indicate that CALM represents a new way of studying arterial health, which has the potential to complement traditional measures of cardiovascular disease risk in humans.
2

Efeitos da terapia com ondas de choque na mecânica ventricular avaliada pela técnica de speckle tracking em pacientes com angina refratária / Effects of shock wave therapy on left ventricular mechanics evaluated by speckle tracking echocardiography in patients with refractory angina

Duque, Anderson Silveira 24 January 2018 (has links)
A doença aterosclerótica coronariana tem um grande impacto na morbidade e mortalidade em todo mundo. A terapia cardíaca com ondas de choque consiste em uma nova opção potencial para o tratamento de pacientes com doença coronariana crônica e angina refratária. No presente estudo, avaliamos os efeitos das ondas de choque na mecânica do ventrículo esquerdo, avaliados pela ecocardiografia com speckle tracking, assim como nos sintomas clínicos e isquemia miocárdica em pacientes com angina refratária. Estudamos, prospectivamente, 19 pacientes com angina refratária submetidos à terapia com ondas de choque com 3 sessões de tratamento por semana, realizados na primeira, quinta e nona semanas, totalizando 9 semanas de tratamento. A mecânica do ventrículo esquerdo foi avaliada por meio da determinação do strain longitudinal global e segmentar. A perfusão miocárdica foi analisada por cintilografia de perfusão miocárdica com Tecnécio-99m Sestamibi, para determinação do summed stress score (SSS). Parâmetros clínicos foram mensurados pelo escore de angina da Canadian Cardiovascular Society (CCS), escore de insuficiência cardíaca da New York Heart Association (NYHA) e qualidade de vida pelo Seattle Angina Questionnaire (SAQ). Todos os dados foram mensurados antes do início do tratamento e 6 meses após a terapia com ondas de choque. Os nossos resultados demonstraram que as ondas de choque não ocasionaram efeitos colaterais importantes e os pacientes apresentaram melhora significativa dos sintomas. Antes do tratamento, 18 (94,7%) pacientes se apresentavam com angina CCS classe III ou IV, e 6 meses após houve redução para 3 (15,8%) pacientes (p = 0,0001), associada à melhora no SAQ (38,5%; p < 0,001). Treze (68,4%) pacientes estavam em classe funcional III ou IV da NYHA antes do tratamento, com redução significativa para 7 (36,8%); p = 0,014. Nenhuma alteração foi observada no SSS global basal no acompanhamento de 6 meses (15,33 ± 8,60 versus 16,60 ± 8,06, p = 0,155) determinado pela cintilografia miocárdica. No entanto, houve redução significativa no SSS médio dos segmentos isquêmicos tratados (2,1 ± 0,87 pré versus 1,6 ± 1,19 pós-terapia, p = 0,024). O strain longitudinal global do ventrículo esquerdo permaneceu inalterado (-13,03 ± 8,96 pré versus -15,88 ± 3,43 pós-tratamento; p = 0,256). Também não foi observada alteração significativa no strain longitudinal segmentar do ventrículo esquerdo pela ecocardiografia com speckle tracking. Concluímos que a terapia com ondas de choque é um procedimento seguro para tratamento de pacientes com angina refratária, que resulta em melhor qualidade de vida, melhora na perfusão miocárdica dos segmentos tratados e preservação da mecânica ventricular esquerda / Coronary atherosclerotic disease represents a major impact on morbidity and mortality worldwide. Cardiac shock wave therapy is a new potential option for the treatment of patients with chronic coronary disease and refractory angina. In the present study, we sought to determine the effects of shock wave therapy on the left ventricular mechanics, evaluated by speckle tracking echocardiography, as well as on myocardial perfusion and symptoms of patients with refractory angina. We prospectively studied 19 patients undergoing shock wave therapy with 3 sessions per week, on the 1st, 5th and 9th weeks, for a total of 9 weeks of treatment. The left ventricular mechanics was evaluated by global longitudinal strain using the speckle tracking echocardiography. Myocardial perfusion was assessed by myocardial scintigraphy with Technetium-99m Sestamibi, for determination of summed stress score (SSS). Clinical parameters were evaluated by the Canadian Cardiovascular Society (CCS) angina score, New York Heart Association (NYHA ) heart failure score and quality of life by the Seattle Angina Questionnaire (SAQ). All data were measured prior to the treatment and 6 months after shock wave therapy. Our results demonstrated that shock wave therapy did not cause significant side effects and improved symptoms. Before treatment, 18 patients (94.7%) had CCS class III or IV angina, and 6 months later there was a reduction to 3 (15.8%), p = 0.0001, associated with improvement in SAQ ( 38.5%, p < 0.001). Thirteen (68.4%) were in NYHA class III or IV before treatment, with a significant reduction to 7 (36.8%); p = 0.014. No change was observed in the global SSS at 6-months follow-up (from 15.33 ± 8.60 baseline to 16.60 ± 8.06 post-treatment, p = 0.155). However, there was a significant reduction in the mean SSS of the treated ischemic segments (2.1 ± 0.87 pre versus 1.6 ± 1.19 post therapy, p = 0.024). The global longitudinal strain remained unchanged (-13.03 ± 8.96 pre versus -15.88 ± 3.43 6 months post-treatment, p = 0.256). In the same way, no significant difference was observed in the longitudinal strain of the left ventricular segments. We concluded that shock wave therapy is a safe procedure for the treatment of patients with refractory angina, resulting in better quality of life, improved myocardial perfusion of the treated segments, and preservation of left ventricular mechanics
3

Efeitos da terapia com ondas de choque na mecânica ventricular avaliada pela técnica de speckle tracking em pacientes com angina refratária / Effects of shock wave therapy on left ventricular mechanics evaluated by speckle tracking echocardiography in patients with refractory angina

Anderson Silveira Duque 24 January 2018 (has links)
A doença aterosclerótica coronariana tem um grande impacto na morbidade e mortalidade em todo mundo. A terapia cardíaca com ondas de choque consiste em uma nova opção potencial para o tratamento de pacientes com doença coronariana crônica e angina refratária. No presente estudo, avaliamos os efeitos das ondas de choque na mecânica do ventrículo esquerdo, avaliados pela ecocardiografia com speckle tracking, assim como nos sintomas clínicos e isquemia miocárdica em pacientes com angina refratária. Estudamos, prospectivamente, 19 pacientes com angina refratária submetidos à terapia com ondas de choque com 3 sessões de tratamento por semana, realizados na primeira, quinta e nona semanas, totalizando 9 semanas de tratamento. A mecânica do ventrículo esquerdo foi avaliada por meio da determinação do strain longitudinal global e segmentar. A perfusão miocárdica foi analisada por cintilografia de perfusão miocárdica com Tecnécio-99m Sestamibi, para determinação do summed stress score (SSS). Parâmetros clínicos foram mensurados pelo escore de angina da Canadian Cardiovascular Society (CCS), escore de insuficiência cardíaca da New York Heart Association (NYHA) e qualidade de vida pelo Seattle Angina Questionnaire (SAQ). Todos os dados foram mensurados antes do início do tratamento e 6 meses após a terapia com ondas de choque. Os nossos resultados demonstraram que as ondas de choque não ocasionaram efeitos colaterais importantes e os pacientes apresentaram melhora significativa dos sintomas. Antes do tratamento, 18 (94,7%) pacientes se apresentavam com angina CCS classe III ou IV, e 6 meses após houve redução para 3 (15,8%) pacientes (p = 0,0001), associada à melhora no SAQ (38,5%; p < 0,001). Treze (68,4%) pacientes estavam em classe funcional III ou IV da NYHA antes do tratamento, com redução significativa para 7 (36,8%); p = 0,014. Nenhuma alteração foi observada no SSS global basal no acompanhamento de 6 meses (15,33 ± 8,60 versus 16,60 ± 8,06, p = 0,155) determinado pela cintilografia miocárdica. No entanto, houve redução significativa no SSS médio dos segmentos isquêmicos tratados (2,1 ± 0,87 pré versus 1,6 ± 1,19 pós-terapia, p = 0,024). O strain longitudinal global do ventrículo esquerdo permaneceu inalterado (-13,03 ± 8,96 pré versus -15,88 ± 3,43 pós-tratamento; p = 0,256). Também não foi observada alteração significativa no strain longitudinal segmentar do ventrículo esquerdo pela ecocardiografia com speckle tracking. Concluímos que a terapia com ondas de choque é um procedimento seguro para tratamento de pacientes com angina refratária, que resulta em melhor qualidade de vida, melhora na perfusão miocárdica dos segmentos tratados e preservação da mecânica ventricular esquerda / Coronary atherosclerotic disease represents a major impact on morbidity and mortality worldwide. Cardiac shock wave therapy is a new potential option for the treatment of patients with chronic coronary disease and refractory angina. In the present study, we sought to determine the effects of shock wave therapy on the left ventricular mechanics, evaluated by speckle tracking echocardiography, as well as on myocardial perfusion and symptoms of patients with refractory angina. We prospectively studied 19 patients undergoing shock wave therapy with 3 sessions per week, on the 1st, 5th and 9th weeks, for a total of 9 weeks of treatment. The left ventricular mechanics was evaluated by global longitudinal strain using the speckle tracking echocardiography. Myocardial perfusion was assessed by myocardial scintigraphy with Technetium-99m Sestamibi, for determination of summed stress score (SSS). Clinical parameters were evaluated by the Canadian Cardiovascular Society (CCS) angina score, New York Heart Association (NYHA ) heart failure score and quality of life by the Seattle Angina Questionnaire (SAQ). All data were measured prior to the treatment and 6 months after shock wave therapy. Our results demonstrated that shock wave therapy did not cause significant side effects and improved symptoms. Before treatment, 18 patients (94.7%) had CCS class III or IV angina, and 6 months later there was a reduction to 3 (15.8%), p = 0.0001, associated with improvement in SAQ ( 38.5%, p < 0.001). Thirteen (68.4%) were in NYHA class III or IV before treatment, with a significant reduction to 7 (36.8%); p = 0.014. No change was observed in the global SSS at 6-months follow-up (from 15.33 ± 8.60 baseline to 16.60 ± 8.06 post-treatment, p = 0.155). However, there was a significant reduction in the mean SSS of the treated ischemic segments (2.1 ± 0.87 pre versus 1.6 ± 1.19 post therapy, p = 0.024). The global longitudinal strain remained unchanged (-13.03 ± 8.96 pre versus -15.88 ± 3.43 6 months post-treatment, p = 0.256). In the same way, no significant difference was observed in the longitudinal strain of the left ventricular segments. We concluded that shock wave therapy is a safe procedure for the treatment of patients with refractory angina, resulting in better quality of life, improved myocardial perfusion of the treated segments, and preservation of left ventricular mechanics

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