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-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.
Postoperative neurocognitive disorders (NCD) are of high priority in perioperative management. The risk of suffering from NCD after surgery may be increased due to perioperative impairment of cerebrovascular autoregulation and thereby inadequate cerebral perfusion. Cerebrovascular autoregulation refers to the ability of cerebral arterioles to ensure constant cerebral blood flow independently of fluctuations in systemic blood pressure. Cerebrovascular autoregulation can be measured based on mean arterial pressure (MAP) and a surrogate for cerebral blood flow using the correlation method. Until today, measurement of cerebral blood flow velocity assessed with transcranial Doppler sonography (TCD) is most commonly used as a non-invasive surrogate for cerebral blood flow. Alternatively, cerebral oxygenation measured with near-infrared spectroscopy (NIRS) can be used as another surrogate. The study includes three substudies: 1. To compare NIRS and TCD for the assessment of perioperative cerebrovascular autoregulation in patients undergoing major non-cardiac surgery with an increased risk of bleeding. 2. To compare MAP for optimal cerebrovascular autoregulation before induction of general anesthesia with MAP for optimal cerebrovascular autoregulation during or after general anesthesia. 3. To analyze the association between the time-weighted average MAP below the MAP for optimal cerebrovascular autoregulation and postoperative NCD.
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.
Cognitive performance is negatively related to an impaired glucose metabolism, possibly due to impairments in brain vascular function. Supported by the statement from the American Heart and Stroke Association that a healthy lifestyle is one of the most effective strategies to protect against cognitive decline, the investigators now hypothesise that healthy lifestyle intervention-induced changes in glucose metabolism cause beneficial effects on brain vascular function thereby improving cognitive performance. The primary objective of this intervention study is thus to evaluate in sedentary older men and women the effect of a 16-week aerobic-based exercise program on cerebral blood flow, as quantified by the non-invasive gold standard magnetic resonance imaging (MRI) perfusion method Arterial Spin Labeling (ASL). Cerebral blood flow is a robust and sensitive physiological marker of brain vascular function. Secondary objectives are to examine effects on glucose metabolism using the homeostatic model assessment for insulin resistance (HOMA-ir) and cognitive performance as assessed with a neurophysiological test battery.
Sedentary behaviour of healthy subjects may have a detrimental impact on cerebral blood flow as well as cognitive measures related to mood and alertness. In this study we focus on the impact of leaving the desk to consume a cup of tea at regular intervals during a sedentary working day.