View clinical trials related to Cerebrovascular Circulation.
Filter by:Ischaemic heart disease (IHD) and degenerative brain disease are two major sources of death and disability affecting all countries. While the consequences of obstructive disease in major vessels supplying blood to both organs have been widely documented, less attention has been paid to disease processes affecting the microcirculation that may affect cardiac and cerebral function. Yet, over the last decade significant progress has been made in understanding the substrate of microvascular disease in both organs. In the heart, arteriolar thickening and capillary rarefaction that reduce the conductance of the microvasculature and its ability to vasodilate in response to increased myocardial oxygen demands constitute the leading cause of coronary microvascular dysfunction (CMD). In the brain, concentric hyaline thickening of deep penetrating small arteries (arteriolosclerosis) with associated fibrosis of the vessel wall constitutes the most frequent substrate for cerebral small vessel disease (CSVD). Of note, both CMD and CSVD share common risk factors, such as age, hypertension, and diabetes.3 These factors might have a common effect on the microvascular domain of cardiac and cerebral vascular beds. Although a potential link between both conditions has been hypothesized based on the similarities between pathological changes and risk factors, advance in knowledge exploring this has been hampered by lacking objective evidence of CMD and pathological brain changes indicative of CSVD in prior research studies. Thus, the relationship between CMD and CSVD is unknown. The main objective of this study was to analyse the relationship between cerebrovascular disease and CMD in patients with atherosclerotic coronary artery disease (CAD).
The goal of this clinical trial is to compare the impact of restricted sleep on brain blood health in healthy men and women. The main question[s] it aims to answer are: - Whether morning cerebral blood flow velocity is greater following a night of normal sleep compared to restricted sleep - Whether the effect of sleep restriction on cerebral blood flow will be greater in males compared to females Participants will complete one 1-hour screening visit and two 2.5-hour study visits. Study visits will be conducted on two separate days.
The objective of the study is to assess brain tissue perfusion by contrast-enhanced ultrasound perfusion imaging (PerCEUS) in acute brain injuries. More precisely, it aims : - to evaluate the heterogeneity of brain perfusion and thus diagnose brain tissue hypoperfusion with contrast-enhanced ultrasound. - to correlate contrast-enhanced ultrasound with perfusion measurements by usual multimodal monitoring.
Brain blood flow will be measured during exercise using magnetic resonance imaging.
This study will investigate the impact of high- and moderate-intensity exercise on the cardiometabolic and brain health of women with Polycystic Ovary syndrome (PCOS). The aim is to measure and compare normal, healthy women without PCOS, to those with the condition. All participants will undergo a blood test. The investigators will then assess the participants cardiovascular fitness by means of a maximal exercise test and measure body composition through height, weight, and hip-to-waist ratio. Participants will undergo an MRI, where the investigators will assess the participants brain structure and how the brain responds to a number of tests. The investigators will also conduct some tests that will assess the participants cognition, such as IQ, memory etc. The investigators will measure the blood vessels leading to the brain and the blood flow through them to measure how much blood the brain receives when rested, using ultrasound. The investigators will use a number of tests to look at brain function, measure the responses to these tests, and compare them between the normal, healthy women and those with PCOS. This will show if women with PCOS have a similar brain function when rested and when their brains are tested to those without the condition. The investigators will use exercise as an intervention, where the aim will be to investigate whether women with PCOS respond similarly to those without the condition to both high-intensity and moderate-intensity exercise. The tests of brain function will be repeated following the exercise, and see if both normal, healthy women and those with PCOS have a similar response to the brain function tests. All tests and measures will be compared between the PCOS group, and the healthy control group to establish any potential differences or similarities as a result of the condition.
Acute ischemic stroke due to large vessel occlusion is responsible of cerebral blood flow impairment with a progressive and extensive ischemic process. Cerebral collateral circulation may preserve an ischemic penumbra that could recover providing timely reperfusion of the occluded vessel. Mechanical thrombectomy is the standard of care for anterior circulation large vessel reperfusion. Strategy to promote cerebral blood flow in collateral circulation before reperfusion is scarce and rely mainly on blood pressure maintenance. Carbon dioxide is a potent cerebral vasodilator that could enhance collateral circulation blood flow and cerebral protection before reperfusion. General anesthesia with endotracheal mechanical ventilation could be used for thrombectomy and give the opportunity to modulate and control carbon dioxide tension in the blood. This study will test the effect of moderate hypercapnia on penumbral collateral circulation before reperfusion during mechanical thrombectomy for anterior circulation acute ischemic stroke under general anesthesia.
The investigators will seek to determine the relationship between heart rate and middle cerebral artery (MCA) cerebral blood flow (CBF), as well as better understand the hemodynamic determinants of MCA CBF velocity. In order to manipulate heart rate, the investigators will recruit patients already scheduled for clinically indicated elective electrophysiological studies, where temporary pacing catheters placed in the right atrium can be used to artificially pace the heart at controlled rates. MCA CBF will be measured by transcranial Doppler ultrasound.
The aim of the study is to assess the correlation of blood flow measurement in cervical and intracranial arteries between quantitative magnetic resonance angiography (qMRA) and duplex sonography (DS) and inter-/intra-investigators reliability of both methods in common clinical practice. A total of 21 subjects indicated to qMRA or DS for suspicion of cervical or intracranial vascular pathology will be included. All patients will undergo qMRA and DS of the cervical and intracranial arteries with measurement of blood flow in bilateral common carotid artery (CCA), internal carotid artery in proximal part distally to carotid bulb (ICA) and in distal carotid siphon (ICA-siphon), external carotid artery (ECA), vertebral artery in V2 (V2-VA) and V4 (V4-VA) segments, middle cerebral artery (MCA), anterior cerebral artery in pre-communicant (ACA1) and post-communicant (ACA2) part, posterior cerebral artery in pre-communicant (PCA1) and post-communicant (PCA2) part and basilar artery (BA) the cerebral artery. Correlations between measurements will be evaluated using Spearman's correlation coefficient or kappa coefficient and inter-class correlation coefficient (ICC).
Congenital heart defects have an incidence of 9/1000 live births. Infants with congenital heart defects such as Transposition of Great Arteries / Hypoplastic Left Heart are at risk for brain injury because of concomitant brain malformations. Previous studies of cerebral MRI in infants with congenital heart defects showed that in 20-40% of cases there was preoperative brain injury and post operative with the same incidence. These findings are strongly associated with early and long-term neurodevelopmental injury. There is a necessity for a non invasive device who will monitor the cerebral blood flow during the hospitalization prior and post the cardiac defect repair surgery. The previous modal of the study device has been cleared for marketing by the FDA (k150268). The main goal of this study is to demonstrate that the new design of Ornim's c-FLOW 3310-P is easy to operate and effective in monitoring changes in cerebral blood flow in neonates as demonstrated in adults.
Background: fluctuation of cerebral blood flow and oxygenation in neonates who undergo intensive care is an important risk factor for risk of neurodevelopmental impairment. Near infrared spectroscopy (NIRS) allow direct measurements of cerebral tissue oxygenation. Automated Fraction of Inspired Oxygen (FiO2) adjustment can maintain arterial oxygen saturation (SpO2) within a target range and may reduce risk of fluctuation of cerebral oxygenation. Aim of this study: to evaluate the efficacy of automated FiO2 adjustment in maintaining SpO2 within a target range and in reducing the risk of cerebral tissue hypo-oxygenation due to SpO2 fluctuations in preterm infants on invasive or non invasive respiratory support with supplemental oxygen.