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Arterial wall morphology depends strongly on the hemodynamic environment experienced in vivo. The mammalian heart pumps blood through rhythmic contractions forcing blood vessels to undergo cyclic, mechanical stimulation in the form of pulsatile blood pressure and flow. While it has been shown that stepwise, chronic increases in blood pressure and flow modify arterial wall thickness and diameter respectively, few studies on arterial remodeling have examined the influences that pulsatility (i.e., the range of cyclic stimuli) may have on biaxial wall morphology. We experimentally studied the biaxial behavior of carotid arteries from 8 control (CCA), 15 transgenic, and 21 mechanically altered mice using a custom designed mechanical testing device and correlated those results with hemodynamic measurements using pulsed Doppler. In this dissertation, we establish that increased pulsatile stimulation in the right carotid artery after banding (RCCA-B) has a strong affect on wall morphological parameters that peak at 2 weeks and include thickness (CCA=24.8±0.878, RCCA-B=99.0±8.43 μ m), inner diameter (CCA=530±7.36, RCCA-B=680±32.0μ m), and in vivo axial stretch (CCA=1.7±0.029, RCCAB= 1.19±0.067). These modifications entail stress and the change in stress across the cardiac cycle from an arterial wall macro-structural point of view (i.e., cellular and extracellular matrix) citing increases in collagen mass fraction (CCA=0.223±0.056, RCCA-B=0.314±0.011), collagen to elastin ratio (CCA=0.708±0.152, RCCA-B=1.487±0.26), and cross-sectional cellular nuclei counts (CCA=298±58.9, RCCA-B=578±28.3 cells) at 0, 7, 10, 14, and 42 post-banding surgery. Furthermore, we study the biomechanical properties of carotid arteries from a transgenic mouse of Marfan Syndrome. This arterial disease experiences increased pulse transmission and our findings indicate that alterations occur primarily in the axial direction. The above results are all applied to a predictive biaxial model of Cauchy stress vs. strain.

Introduction: Heart failure remains a major public health problem, with recent estimates indicating that end-stage heart failure with two-year mortality rates of 70-80% affects over 60,000 patients in the US each year. Medical management can be used but success declines for patients with end stage heart failure. Although cardiac transplantation is optimal, less than 2500 cardiac transplants are performed annually due to the severely limited supply of donor organs. Mechanical circulatory support (MCS) devices are now routinely used to bridge patients with end-stage heart failure who become critically ill until a donor heart is available. The use of stem cell therapy to treat heart failure has been gaining significant ground in recent years, specifically due to its regenerative properties, and both animal and human models have shown significant improvements in ventricular mass, ejection fraction, vascularization, wall thickness, and infarct size reduction. Using the patients' HeartWare HVAD device diagnostics, we were able to acquire our response variable; pulsatility. Pulsatility is a variable measure of the differential between minimum and maximum flow and is dependent on device motor speed, power, current, and fluid viscosity. This measurement is important as it relates to the contractility of the heart and could potentially be used as an end point in determining when a patient is healthy enough to have their HVAD explanted. We set out to develop a low cost and effective predictive model to determine amniotic mesenchymal stem cell's ability to repair compromised cardiac tissue of patients using the Total Artificial Heart (TAH) and Donovan Mock Circulation Tank (DMC). Methods: Predictive modelling was performed using the TAH and DMC. The system was set to a range from critical heart failure to a normal operating conditions through the variation of preload, afterload, and ventricular drive pressures with the intent of comparing the results to our patient population. Patients (n=7, 3 dilated, 4 ischemic) received intravenous and intra-myocardial injections of a heterogeneous amniotic mesenchymal stem cells mixture and liquid matrix (MSCs+LM) at HVAD implant. Groups were analyzed based on treatment; control (HVAD only, n=7) versus stem cells (HVAD + MSCs+LM). HeartWare log files were acquired from patients' devices and analyzed in SAS and Matlab. Results from the patient study were compared to the predictive model to determine levels of stem cell response. Results: Pulsatility was found to increase with left drive pressure and afterload. Lower drive pressures resulted in a drop off in pulsatility at higher afterloads while higher drive pressures were able to compensate for any afterload. Pulsatility also increased with preload but lower drive pressures were unable to fully eject at the highest preloads, resulting in a reduced pulsatility. We observed the effects of the stem cell injections on pulsatility and found that patients receiving therapy demonstrated statistically significant increases in pulsatility at 15-20 (p=.0487), 25-30 (p=.0131), 35-40 (p=.0333), and 75-80 (p=0.0476) days post implant. At minimum, when comparing the patient results to the in vitro model, the therapy resulted in a progression from end stage HF conditions to medium cardiac function conditions. At maximum, the therapy resulted in a progression from end stage HF to normal healthy operating cardiac function. Conclusions: Stem cells demonstrated a significantly increased rate of change in pulsatility within the first 40 days and at 80 days post implant when compared to control. They also demonstrated progression from end stage HF to normal healthy cardiac function at two time periods (Days 40, 90). These results justify expansion of the study to encompass a larger patient population to verify the results of the in vitro model to predict cardiac regeneration with multiple functional status indicators.

Cerebral small vessel disease (SVD) is associated with increased risks of stroke and dementia, however the mechanisms remain unclear. Low cerebral blood flow (CBF) has long been suggested and accepted, but clinical evidence is conflicting. On the other hand, growing evidence suggests that increased intracranial pulsatility due to vascular stiffening might be an alternative mechanism. Pulse-gated phase-contrast MRI is an imaging technique that allows measuring of CBF contemporaneously with pulsatility in multiple vessels and cerebrospinal fluid (CSF) spaces. The overall aim of this thesis was to provide an overview of existing clinical evidence on both hypotheses, to test the reproducibility of CBF and pulsatility measures in phase-contrast MRI, and to explore the relationship between CBF and intracranial pulsatility and SVD features in a group of patients with minor stroke and SVD changes on brain imaging. I first systematically reviewed and meta-analysed clinical studies that have assessed CBF or intracranial pulsatility in SVD patients. There were 38 studies (n=4006) on CBF and 27 (n=3356) on intracranial pulsatility. Most were cross-sectional, and longitudinal studies were scarce. There were large heterogeneities in patient characteristics and indices used particularly for measuring and calculating pulsatility. Methods to reduce bias such as blinding and the expertise of structural image readers were generally poorly reported, and many studies did not account for the impact of confounding factors (e.g. age, vascular risk factors and disease severity) on CBF or pulsatility. Evidence for falling CBF predating SVD was not supported by longitudinal studies; high pulsatility in one large artery such as internal carotid arteries (ICA) or middle cerebral arteries might be related to SVD, but studies that measured arteries, veins and CSF in the same patients were very limited and the reliability of some pulsatility measures, especially in CSF, needs to be tested. In order to test the reproducibility of the CBF and intracranial pulsatility measures, I repeated 2D phase-contrast MRI scans of vessels and CSF on healthy volunteers during two visits. I also compared the ICA pulsatility index derived from the MRI flow waveform to that from the Doppler ultrasound velocity waveform in patients with minor stroke and SVD features. In 10 heathy volunteers (age 35.2±9.78 years), the reproducibility of CBF and vascular pulsatility indices was good, with within-subject coefficients of variability (CV) less than 10%; whereas CSF flow and pulsatility measures were generally less reproducible (CV > 20%). In 56 patients (age 67.8±8.27 years), the ICA pulsatility indices in Doppler ultrasound and MRI were acceptably well-correlated (r=0.5, p < 0.001) considering the differences in the two techniques. We carried out a cross-sectional study aiming to recruit 60 patients with minor stroke and SVD features. We measured CBF and intracranial pulsatility using phase-contrast MRI, as well as aortic augmentation index (AIx) using a SphygmoCor device. I first investigated the relationship between intracranial measures, and systemic blood pressure or aortic AIx, and then focused on how the intracranial haemodynamic measures related to two main SVD features (white matter hyperintensities (WMH) and perivascular spaces (PVS)). We obtained usable data from 56/60 patients (age 67.8±8.27 years), reflecting a range of SVD burdens. After the adjustment for age, gender, and history of hypertension, higher pulsatility in the venous sinuses was associated with lower diastolic blood pressure and lower mean arterial pressure (e.g. diastolic blood pressure on straight sinus pulsatility index (PI): β=-0.005, P=0.029), but not with aortic AIx. Higher aortic AIx was associated with low ICA PI (β=-0.011, P=0.040). Increased pulsatility in the venous sinuses, not low CBF, was associated with greater WMH volume (e.g. superior sagittal sinus PI: β=1.29, P=0.005) and more basal ganglia PVS (e.g. odds ratio=1.379 per 0.1 increase in superior sagittal sinus PI) after the adjustment for age, gender and blood pressure. The thesis is the first to summarise the literature on CBF and intracranial pulsatility in SVD patients, addressed the major limitations of current clinical studies of SVD, and also assessed CBF and intracranial pulsatility contemporaneously in well-characterised patients with SVD features. The overall results of the thesis challenge the traditional hypothesis of the cause and effect between low CBF and SVD, and suggest that increased cerebrovascular pulsatility, which might be due to intrinsic cerebral small vessel pathologies rather than just aortic stiffness, is important for SVD. More importantly, this pilot study also provides a reliable methodology for measuring intracranial pulsatility using phase-contrast MRI for future longitudinal or larger multicentre studies, and shows that intracranial pulsatility could be used as a secondary outcome in clinical trials of SVD. However, future research is required to elucidate the implication of venous pulsatility and to fully explore the passage of pulse wave transmission in the brain. Overall, this thesis advances knowledge and suggest potential targets for future SVD studies in terms of mechanisms, prevention and treatment.

Informações em tempo real da direção e tipo de fluxo sanguíneo podem ser obtidas com ultrassonografia com Doppler. Não foram encontrados dados na literatura de valores obtidos por este método da artéria celíaca e mesentérica cranial de gatos. Além disso, ocasionalmente há necessidade de sedar os gatos e cães para realização deste exame em quaisquer vasos em que se deseja obter mais informações. O trabalho possui dois objetivos. Um foi avaliar os aspectos quantitativos da onda espectral formada pelo fluxo sanguíneo das artérias: aorta, celíaca, mesentérica cranial, renal, ilíaca externa e femoral de gatos e cães hígidos; e compará-los aos obtidos dos mesmos animais submetidos à sedação, com um protocolo para cada espécie. Os gatos foram sedados com midazolam, cetamina e butorfanol, e os cães, com acepromazina e butorfanol. Outro objetivo foi obter valores velocimétricos de referência para artéria celíaca e artéria mesentérica cranial em gatos, através do Doppler espectral. Para isso, foram avaliados 20 gatos e 20 cães hígidos. Como resultado dos gatos, foram obtidos os valores de pico de velocidade sistólica, velocidade diastólica final, média da velocidade média, média da velocidade máxima, índice de resistividade e índice de pulsatilidade, tanto da artéria celíaca quanto da artéria mesentérica cranial de animais hígidos não sedados, e; foram obtidos esses mesmos dados das artérias aorta, renal, ilíaca externa e femoral e todos comparados entre os gatos sedados e não sedados, onde não foram encontradas diferenças estatisticamente significativas, exceto na velocidade diastólica final e velocidade média da artéria celíaca, e índice de resistividade e de pulsatilidade da artéria ilíaca. Já nos cães, observou-se que houve diferença de pelo menos dois dos parâmetros dopplervelocimétricos avaliados das artérias selecionadas, exceto da artéria femoral. Dessa forma, nos gatos foram fornecidos parâmetros dopplervelocimétricos da artéria celíaca e mesentérica cranial de animais não sedados, e conclui-se que, enquanto o protocolo utilizado nos gatos, com midazolam, cetamina e butorfanol, não alterou os valores encontrados nos vasos selecionados, exceto da artéria celíaca e da ilíaca; nos cães, o uso de acepromazina e butorfanol levou a modificação de parte desses valores em todos os vasos, exceto na artéria femoral. Assim, na realização deste exame com esses protocolos, essas diferenças devem ser consideradas. / Real time information about direction and type of blood flow can be obtained with Doppler ultrasound. No data was found in the literature regarding values of the celiac and cranial mesenteric artery in cats obtained through this method. Moreover, occasionally, for examining cats and dogs’ vessels about which we desire to get more information, there is a need to sedate these animals. This study has two objectives. One was to evaluate the quantitative aspects of spectral wave formed by the blood flow of aorta, celiac, cranial mesenteric, renal, external iliac and femoral arteries from healthy cats and dogs and compare them to the same animal under sedation, using one protocol for each species. The cats were sedated with midazolam, ketamine and butorphanol and the dogs with acepromazine and butorphanol. The second objective was to obtain velocimetric reference values from celiac and mesenteric cranial artery in cats. Twenty healthy cats and dogs were evaluated. As a result for the cats, values of peak systolic velocity, end diastolic velocity, time averaged mean velocity, time averaged maximum velocity, resistivity index and pulsatility index of both the celiac and the cranial mesenteric artery were obtained in healthy non-sedated animals, and; these same data from aorta, renal, external iliac and femoral were obtained, and all compared, between sedated and non-sedated cats, where statistically significant differences were not found, except in end diastolic velocity and average speed of the celiac artery, and resistance and pulsatility index of the iliac artery. In dogs, a difference was observed in at least two of the Doppler velocity parameters measured of the arteries, except for the femoral artery. Thus, Doppler velocity parameters of the celiac and cranial mesenteric artery in non-sedated cats were provided and it was concluded that the protocol used in cats, with midazolam, ketamina and buthorphanol did not alter the values of Doppler ultrasound in the selected vessels in cats, except celiac and external iliac artery. In addition, in dogs, the use of acepromazine and buthorphanol led to modification of part of these values in all vessels, except in the femoral artery. Thus, when carrying out this examination with these protocols, such differences should be considered.

During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects. Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile stress were assessed in healthy elderly. The biomarkers were extracted from invasive CSF pressure measurements as well as 2D PCMRI acquisitions. The volumes of temporal cortex, frontal cortex and hippocampus were negatively related to the magnitude of cardiac-related intracranial pulsatility. Finally, a potentially improved workflow to assess the volume of arterial pulsatility using time resolved, four-dimensional phase contrast MRI measurements (4D PCMRI) was evaluated. The measurements showed good agreement with 2D PCMRI acquisitions. In conclusion, this work showed that 2D PCMRI is a feasible tool to study the pulsatile waveforms of cerebral blood and CSF flow. Conventional views regarding the magnitude and distribution of craniospinal compliance was challenged, with important implications regarding the understanding of how intracranial vascular pulsatility is absorbed. A first counterpoint to previous near-uniform observations of obstructions in the internal jugular veins in multiple sclerosis was provided. It was demonstrated that large cardiac- related intracranial pulsatility were related to smaller volumes of brain regions that are important in neurodegenerative diseases among elderly. This represents a strong rationale to further investigate the role of excessive intracranial pulsatility in cognitive impairment and dementia. For that work, 4D PCMRI will facilitate an effective analysis of cerebral blood flow and pulsatility.

Introdução- Os movimentos respiratórios têm influência na circulação fetal. Sua presença indica um sistema nervoso intacto, não deprimido, refletindo o bem-estar do concepto. Acredita-se que, em apnéia, a pressão exercida pelos órgãos intratorácicos no coração fetal, em particular os pulmões não expandidos, limita a distensibilidade ventricular. O padrão de fluxo das veias pulmonares, um parâmetro para avaliação Doppler-ecocardiográfica da função diastólica fetal, é determinado pelos eventos que ocorrem do lado esquerdo do coração, sendo influenciado pelas mudanças dinâmicas na pressão do átrio esquerdo criadas pela contração e pelo relaxamento do átrio e do ventrículo esquerdos. A impedância ao fluxo da veia pulmonar para o átrio esquerdo é representada pelo índice de pulsatilidade. Objetivo- Testar a hipótese de que o índice de pulsatilidade do fluxo venoso pulmonar fetal é menor na presença dos movimentos respiratórios fetais do que em apnéia. Métodos- Examinados 22 fetos normais de mães sem doença sistêmica, em apnéia (controles) e na presença de movimentos respiratórios fetais (casos). Os fetos foram examinados pela ecocardiografia pré-natal com Doppler e mapeamento de fluxo em cores. O índice de pulsatilidade da veia pulmonar foi obtido colocando-se a amostra volume do Doppler pulsado sobre a veia pulmonar superior direita ou inferior esquerda, e aplicando-se a fórmula velocidade máxima (sistólica ou diastólica)-velocidade pré-sistólica/velocidade média. Resultados- Os fetos apresentaram idade gestacional média de 28,9 ± 2,9 semanas. Na avaliação realizada nos fetos em apnéia as médias das velocidades sistólica, diastólica e pré-sistólica foram, respectivamente, 0,35 ± 0,08 m/s, 0,26 ± 0,07 m/s, 0,09 ± 0,03 m/s. Na avaliação realizada na presença de movimentos respiratórios fetais as médias das velocidades sistólica, diastólica e pré-sistólica foram, respectivamente, 0,33 ± 0,1 m/s, 0,28 ± 0,08 m/s, 0,11 ± 0,04 m/s. O índice de pulsatilidade da veia pulmonar médio, nos fetos em apnéia, foi de 1,25 ± 0,23 (1,69 a 0,82), e na presença de movimentos respiratórios fetais foi de 0,97 ± 0,2 (1,53 a 0,61). Conclusão- Demonstramos significante diminuição da impedância ao fluxo venoso pulmonar, representada pelo índice de pulsatilidade vascular, durante os movimentos respiratórios fetais, refletindo modificações da dinâmica atrial esquerda e da melhora complacência ventricular esquerda. / Introdution- Respiratory movements influence fetal circulation. Their presence indicates an intact, non-depressed nervous system, reflecting a good fetal clinical status. In apnea, the pressure of intrathoracic organs on the fetal heart, mainly the non-expanded lungs, limits ventricular distensibility. Flow pattern in pulmonary veins, a Doppler echocardiographic parameter in the assessment of fetal diastolic function, is determined by events occurring in the left heart and is influenced by dynamic changes in left atrial pressures created by left atrium and ventricle contraction and relaxation. Impedance to pulmonary venous flow to the left atrium is represented by the pulsatility index. Objective- To test the hypothesis that fetal pulmonary venous flow pulsatility index is lower during fetal respiratory movements than in apnea. Methods- Twenty-two normal fetuses of mothers without systemic disease were examined in apnea (controls) and in the presence of fetal respiratory movements (cases). Fetuses were examined by prenatal Doppler echocardiography with color flow mapping. The pulsatility index of the pulmonary vein was obtained placing the pulsed Doppler sample volume over the right upper or left lower pulmonary vein , and applying the formula [maximum velocity (systolic or diastolic)–pre-systolic velocity]/mean velocity. Results- Mean gestational age was 28.9 ± 2.9 weeks. During fetal apnea, mean systolic, diastolic and pre-systolic velocities were, respectively, 0.35 ± 0.08 m/s, 0.26 ± 0.07 m/s and 0.09 ± 0.03 m/s. In the presence of fetal respiratory movements, mean systolic, diastolic and pre-systolic velocities were, respectively, 0.33 ± 0.1 m/s, 0.28 ± 0.08 m/s and 0.11 ± 0.04 m/s. Pulsatility index pulmonary vein in apnea was 1.25 ± 0.23 (1.69 to 0.82), and during fetal respiratory movements it was 0.97 ± 0.2 (1.53 to 0.61). Conclusion- We showed a significant reduction in impedance of pulmonary venous flow, represented by pulmonary vein pulsatility index, during fetal respiratory movements, reflecting modifications of the left atrial dynamics and enhancement of left ventricular compliance.

Introdução- Os movimentos respiratórios têm influência na circulação fetal. Sua presença indica um sistema nervoso intacto, não deprimido, refletindo o bem-estar do concepto. Acredita-se que, em apnéia, a pressão exercida pelos órgãos intratorácicos no coração fetal, em particular os pulmões não expandidos, limita a distensibilidade ventricular. O padrão de fluxo das veias pulmonares, um parâmetro para avaliação Doppler-ecocardiográfica da função diastólica fetal, é determinado pelos eventos que ocorrem do lado esquerdo do coração, sendo influenciado pelas mudanças dinâmicas na pressão do átrio esquerdo criadas pela contração e pelo relaxamento do átrio e do ventrículo esquerdos. A impedância ao fluxo da veia pulmonar para o átrio esquerdo é representada pelo índice de pulsatilidade. Objetivo- Testar a hipótese de que o índice de pulsatilidade do fluxo venoso pulmonar fetal é menor na presença dos movimentos respiratórios fetais do que em apnéia. Métodos- Examinados 22 fetos normais de mães sem doença sistêmica, em apnéia (controles) e na presença de movimentos respiratórios fetais (casos). Os fetos foram examinados pela ecocardiografia pré-natal com Doppler e mapeamento de fluxo em cores. O índice de pulsatilidade da veia pulmonar foi obtido colocando-se a amostra volume do Doppler pulsado sobre a veia pulmonar superior direita ou inferior esquerda, e aplicando-se a fórmula velocidade máxima (sistólica ou diastólica)-velocidade pré-sistólica/velocidade média. Resultados- Os fetos apresentaram idade gestacional média de 28,9 ± 2,9 semanas. Na avaliação realizada nos fetos em apnéia as médias das velocidades sistólica, diastólica e pré-sistólica foram, respectivamente, 0,35 ± 0,08 m/s, 0,26 ± 0,07 m/s, 0,09 ± 0,03 m/s. Na avaliação realizada na presença de movimentos respiratórios fetais as médias das velocidades sistólica, diastólica e pré-sistólica foram, respectivamente, 0,33 ± 0,1 m/s, 0,28 ± 0,08 m/s, 0,11 ± 0,04 m/s. O índice de pulsatilidade da veia pulmonar médio, nos fetos em apnéia, foi de 1,25 ± 0,23 (1,69 a 0,82), e na presença de movimentos respiratórios fetais foi de 0,97 ± 0,2 (1,53 a 0,61). Conclusão- Demonstramos significante diminuição da impedância ao fluxo venoso pulmonar, representada pelo índice de pulsatilidade vascular, durante os movimentos respiratórios fetais, refletindo modificações da dinâmica atrial esquerda e da melhora complacência ventricular esquerda. / Introdution- Respiratory movements influence fetal circulation. Their presence indicates an intact, non-depressed nervous system, reflecting a good fetal clinical status. In apnea, the pressure of intrathoracic organs on the fetal heart, mainly the non-expanded lungs, limits ventricular distensibility. Flow pattern in pulmonary veins, a Doppler echocardiographic parameter in the assessment of fetal diastolic function, is determined by events occurring in the left heart and is influenced by dynamic changes in left atrial pressures created by left atrium and ventricle contraction and relaxation. Impedance to pulmonary venous flow to the left atrium is represented by the pulsatility index. Objective- To test the hypothesis that fetal pulmonary venous flow pulsatility index is lower during fetal respiratory movements than in apnea. Methods- Twenty-two normal fetuses of mothers without systemic disease were examined in apnea (controls) and in the presence of fetal respiratory movements (cases). Fetuses were examined by prenatal Doppler echocardiography with color flow mapping. The pulsatility index of the pulmonary vein was obtained placing the pulsed Doppler sample volume over the right upper or left lower pulmonary vein , and applying the formula [maximum velocity (systolic or diastolic)–pre-systolic velocity]/mean velocity. Results- Mean gestational age was 28.9 ± 2.9 weeks. During fetal apnea, mean systolic, diastolic and pre-systolic velocities were, respectively, 0.35 ± 0.08 m/s, 0.26 ± 0.07 m/s and 0.09 ± 0.03 m/s. In the presence of fetal respiratory movements, mean systolic, diastolic and pre-systolic velocities were, respectively, 0.33 ± 0.1 m/s, 0.28 ± 0.08 m/s and 0.11 ± 0.04 m/s. Pulsatility index pulmonary vein in apnea was 1.25 ± 0.23 (1.69 to 0.82), and during fetal respiratory movements it was 0.97 ± 0.2 (1.53 to 0.61). Conclusion- We showed a significant reduction in impedance of pulmonary venous flow, represented by pulmonary vein pulsatility index, during fetal respiratory movements, reflecting modifications of the left atrial dynamics and enhancement of left ventricular compliance.

Informações em tempo real da direção e tipo de fluxo sanguíneo podem ser obtidas com ultrassonografia com Doppler. Não foram encontrados dados na literatura de valores obtidos por este método da artéria celíaca e mesentérica cranial de gatos. Além disso, ocasionalmente há necessidade de sedar os gatos e cães para realização deste exame em quaisquer vasos em que se deseja obter mais informações. O trabalho possui dois objetivos. Um foi avaliar os aspectos quantitativos da onda espectral formada pelo fluxo sanguíneo das artérias: aorta, celíaca, mesentérica cranial, renal, ilíaca externa e femoral de gatos e cães hígidos; e compará-los aos obtidos dos mesmos animais submetidos à sedação, com um protocolo para cada espécie. Os gatos foram sedados com midazolam, cetamina e butorfanol, e os cães, com acepromazina e butorfanol. Outro objetivo foi obter valores velocimétricos de referência para artéria celíaca e artéria mesentérica cranial em gatos, através do Doppler espectral. Para isso, foram avaliados 20 gatos e 20 cães hígidos. Como resultado dos gatos, foram obtidos os valores de pico de velocidade sistólica, velocidade diastólica final, média da velocidade média, média da velocidade máxima, índice de resistividade e índice de pulsatilidade, tanto da artéria celíaca quanto da artéria mesentérica cranial de animais hígidos não sedados, e; foram obtidos esses mesmos dados das artérias aorta, renal, ilíaca externa e femoral e todos comparados entre os gatos sedados e não sedados, onde não foram encontradas diferenças estatisticamente significativas, exceto na velocidade diastólica final e velocidade média da artéria celíaca, e índice de resistividade e de pulsatilidade da artéria ilíaca. Já nos cães, observou-se que houve diferença de pelo menos dois dos parâmetros dopplervelocimétricos avaliados das artérias selecionadas, exceto da artéria femoral. Dessa forma, nos gatos foram fornecidos parâmetros dopplervelocimétricos da artéria celíaca e mesentérica cranial de animais não sedados, e conclui-se que, enquanto o protocolo utilizado nos gatos, com midazolam, cetamina e butorfanol, não alterou os valores encontrados nos vasos selecionados, exceto da artéria celíaca e da ilíaca; nos cães, o uso de acepromazina e butorfanol levou a modificação de parte desses valores em todos os vasos, exceto na artéria femoral. Assim, na realização deste exame com esses protocolos, essas diferenças devem ser consideradas. / Real time information about direction and type of blood flow can be obtained with Doppler ultrasound. No data was found in the literature regarding values of the celiac and cranial mesenteric artery in cats obtained through this method. Moreover, occasionally, for examining cats and dogs’ vessels about which we desire to get more information, there is a need to sedate these animals. This study has two objectives. One was to evaluate the quantitative aspects of spectral wave formed by the blood flow of aorta, celiac, cranial mesenteric, renal, external iliac and femoral arteries from healthy cats and dogs and compare them to the same animal under sedation, using one protocol for each species. The cats were sedated with midazolam, ketamine and butorphanol and the dogs with acepromazine and butorphanol. The second objective was to obtain velocimetric reference values from celiac and mesenteric cranial artery in cats. Twenty healthy cats and dogs were evaluated. As a result for the cats, values of peak systolic velocity, end diastolic velocity, time averaged mean velocity, time averaged maximum velocity, resistivity index and pulsatility index of both the celiac and the cranial mesenteric artery were obtained in healthy non-sedated animals, and; these same data from aorta, renal, external iliac and femoral were obtained, and all compared, between sedated and non-sedated cats, where statistically significant differences were not found, except in end diastolic velocity and average speed of the celiac artery, and resistance and pulsatility index of the iliac artery. In dogs, a difference was observed in at least two of the Doppler velocity parameters measured of the arteries, except for the femoral artery. Thus, Doppler velocity parameters of the celiac and cranial mesenteric artery in non-sedated cats were provided and it was concluded that the protocol used in cats, with midazolam, ketamina and buthorphanol did not alter the values of Doppler ultrasound in the selected vessels in cats, except celiac and external iliac artery. In addition, in dogs, the use of acepromazine and buthorphanol led to modification of part of these values in all vessels, except in the femoral artery. Thus, when carrying out this examination with these protocols, such differences should be considered.

Informações em tempo real da direção e tipo de fluxo sanguíneo podem ser obtidas com ultrassonografia com Doppler. Não foram encontrados dados na literatura de valores obtidos por este método da artéria celíaca e mesentérica cranial de gatos. Além disso, ocasionalmente há necessidade de sedar os gatos e cães para realização deste exame em quaisquer vasos em que se deseja obter mais informações. O trabalho possui dois objetivos. Um foi avaliar os aspectos quantitativos da onda espectral formada pelo fluxo sanguíneo das artérias: aorta, celíaca, mesentérica cranial, renal, ilíaca externa e femoral de gatos e cães hígidos; e compará-los aos obtidos dos mesmos animais submetidos à sedação, com um protocolo para cada espécie. Os gatos foram sedados com midazolam, cetamina e butorfanol, e os cães, com acepromazina e butorfanol. Outro objetivo foi obter valores velocimétricos de referência para artéria celíaca e artéria mesentérica cranial em gatos, através do Doppler espectral. Para isso, foram avaliados 20 gatos e 20 cães hígidos. Como resultado dos gatos, foram obtidos os valores de pico de velocidade sistólica, velocidade diastólica final, média da velocidade média, média da velocidade máxima, índice de resistividade e índice de pulsatilidade, tanto da artéria celíaca quanto da artéria mesentérica cranial de animais hígidos não sedados, e; foram obtidos esses mesmos dados das artérias aorta, renal, ilíaca externa e femoral e todos comparados entre os gatos sedados e não sedados, onde não foram encontradas diferenças estatisticamente significativas, exceto na velocidade diastólica final e velocidade média da artéria celíaca, e índice de resistividade e de pulsatilidade da artéria ilíaca. Já nos cães, observou-se que houve diferença de pelo menos dois dos parâmetros dopplervelocimétricos avaliados das artérias selecionadas, exceto da artéria femoral. Dessa forma, nos gatos foram fornecidos parâmetros dopplervelocimétricos da artéria celíaca e mesentérica cranial de animais não sedados, e conclui-se que, enquanto o protocolo utilizado nos gatos, com midazolam, cetamina e butorfanol, não alterou os valores encontrados nos vasos selecionados, exceto da artéria celíaca e da ilíaca; nos cães, o uso de acepromazina e butorfanol levou a modificação de parte desses valores em todos os vasos, exceto na artéria femoral. Assim, na realização deste exame com esses protocolos, essas diferenças devem ser consideradas. / Real time information about direction and type of blood flow can be obtained with Doppler ultrasound. No data was found in the literature regarding values of the celiac and cranial mesenteric artery in cats obtained through this method. Moreover, occasionally, for examining cats and dogs’ vessels about which we desire to get more information, there is a need to sedate these animals. This study has two objectives. One was to evaluate the quantitative aspects of spectral wave formed by the blood flow of aorta, celiac, cranial mesenteric, renal, external iliac and femoral arteries from healthy cats and dogs and compare them to the same animal under sedation, using one protocol for each species. The cats were sedated with midazolam, ketamine and butorphanol and the dogs with acepromazine and butorphanol. The second objective was to obtain velocimetric reference values from celiac and mesenteric cranial artery in cats. Twenty healthy cats and dogs were evaluated. As a result for the cats, values of peak systolic velocity, end diastolic velocity, time averaged mean velocity, time averaged maximum velocity, resistivity index and pulsatility index of both the celiac and the cranial mesenteric artery were obtained in healthy non-sedated animals, and; these same data from aorta, renal, external iliac and femoral were obtained, and all compared, between sedated and non-sedated cats, where statistically significant differences were not found, except in end diastolic velocity and average speed of the celiac artery, and resistance and pulsatility index of the iliac artery. In dogs, a difference was observed in at least two of the Doppler velocity parameters measured of the arteries, except for the femoral artery. Thus, Doppler velocity parameters of the celiac and cranial mesenteric artery in non-sedated cats were provided and it was concluded that the protocol used in cats, with midazolam, ketamina and buthorphanol did not alter the values of Doppler ultrasound in the selected vessels in cats, except celiac and external iliac artery. In addition, in dogs, the use of acepromazine and buthorphanol led to modification of part of these values in all vessels, except in the femoral artery. Thus, when carrying out this examination with these protocols, such differences should be considered.