Clinical Research Directory

Correlation Between Carotid Stump Pressure and Interhemispheric rSO₂ Asymmetry During Awake Carotid Endarterectomy

This study aims to better understand how well the brain is perfused (supplied with blood and oxygen) during a specific type of surgery called carotid endarterectomy (CEA), which is performed to prevent strokes in people with stenosis of carotid arteries. During this surgery, the surgeon temporarily clamps the carotid artery to remove a blockage, which can reduce blood flow to the brain. Monitoring brain oxygen levels during this time is important to prevent brain injury. Two common monitoring methods are: Stump pressure (SP) - a pressure measurement taken from the carotid artery during surgery. Near-infrared spectroscopy (NIRS) - a non-invasive technique that tracks brain oxygen levels in real time. This study focuses on the relationship between carotid stump pressure and differences in brain oxygenation between the two sides of the brain (interhemispheric asymmetry), as measured by NIRS. The study will include patients undergoing awake CEA (under regional anesthesia) at a single center university hospital. Oxygen levels in both hemispheres of the brain will be monitored before and after the carotid artery is clamped after 3 minutes. Stump pressure will also be measured. The researchers will examine whether low stump pressure is linked to greater differences in brain oxygen levels between the two sides. The primary goal is to determine whether a large difference in brain oxygenation between the two hemispheres (greater than 10%) is associated with low carotid stump pressure. Secondary goals include identifying a stump pressure threshold that predicts significant asymmetry and analyzing the influence of patient and surgical factors. The findings may help improve how surgeons and anesthesiologists monitor and protect the brain during CEA, particularly in patients who are awake and can be observed for neurological changes.

CEReBral AutorEgulation in Non-cardiac SuRgery and Relationship to Postoperative DeliriUm State

The goal of this observational study is to learn the how to determine the mean arterial pressure(MAP) or blood pressure level to be maintained during non-cardiac surgery for optimal brain health in patients above the age of 60 undergoing major non-cardiac surgery. The main question\[s\] it aims to answer are: * Is there a way to tailor the blood pressure to be maintained in such patients during surgery for optimal brain health using non-invasive monitors that check the brains electrical activity, the electroencephalogram(EEG) monitor, and the brain's blood oxygen levels, the cerebral oximetry(CO) monitor? * How much does this optimal blood pressure level vary between patients? Participants will be asked to: * Complete a questionnaire at the time they enroll into the study, as well as a daily questionnaire to help determine their level of thinking and brain health. This questionnaire will be administered by a member of the study team. * They will also have an EEG and CO monitoring sticker placed on their foreheads. This will be connected to a monitor that will collect this data just before, during, and after their surgery. The data collected through these monitors will help us with our study goals.

The Effect of Controlled Hypotension

Controlled hypotension is currently used in spinal surgery to reduce bleeding at the surgical site, improve the surgeon's visibility, and decrease intraoperative blood loss. Although controlled hypotension is considered a beneficial method from a surgical perspective, it is important to be cautious about its side effects. One such side effect is cerebral perfusion insufficiency, which can be managed by monitoring cerebral circulation through regional cerebral oxygen saturation (rSO2). The aim of this study is to compare the effects of controlled hypotension at specific MAP ranges on cerebral oxygen saturation.

Test of Reproducibility of [15O]H20-PET Assessment of Brain Perfusion

In the aging population, ischemic heart disease, stroke and dementia are increasingly prevalent. Diagnosis and treatment of the former two i.e., large-vessel coronary heart disease and endovascular thrombectomy of the brain in relation to stroke have improved significantly. Yet, the majority of elderly patients with ischemic heart disease do not have large-vessel heart disease and it seems that small vessel disease (SVD) may explain a large fraction of these cases as well as the cardiovascular morbidity in the elderly. Hence, the current development in diagnostics and treatments of ischemic heart disease does not address the most common subtype of ischemic disease seen in elderly patients. It has been suggested that SVD is part of a multisystem disorder and several systematic reviews have addressed the hypothesis of a potential link between small vessel disease of the heart, brain, and kidneys. Cerebral SVD is prevalent in the aging population causing cognitive impairment, dementia, and an increased risk of stroke, and cerebral hypoperfusion is an acknowledged cause of vascular dementia and a possible cause of Alzheimer's disease. Further, cognitive impairment within multiple cognitive domains is highly prevalent in heart failure and is associated to an increased risk of dementia. The link between heart failure and dementia may be due to multisystem SVD, although a direct link between the two is possible. Among other known risk factors such as age, hypertension, and female sex, diabetes is a major cause of SVD and is linked to coronary heart disease as well as cognitive impairment. The diagnosis of cerebral SVD relies on MRI detecting infarctions, haemorrhages, microbleeds and ischemic white matter changes, i.e. Fazekas score. In contrast, perfusion PET is used to image myocardial perfusion in patients with coronary SVD; and coronary SVD is recognized as a part of the pathophysiology in angina, coronary artery disease, and heart failure. Perfusion PET before and after adenosine-induced vasodilation allows for measuring, the myocardial flow reserve (MFR), i.e. perfusion capacity, which in the absence of regional perfusion defects, is a measure of coronary SVD. Prof. Eva Prescott have recently shown that reduced MFR obtained by 82Rb PET is a strong predictor of future microvascular events and all-cause mortality. Exercise is well known to improve cognitive health but professor Carl-Johan Boraxbekk has shown that the effect on cognitive performance may be dependent on the initial cerebrovascular status, as patients with moderate to severe white matter changes did not improve after a 6 months physical activation intervention in contrast to patients with mild changes. Yet, it is possible to improve brain function in diabetic patients through either dietary or exercise interventions. Systemic SVD is measured as cerebral SVD (reduced brain perfusion during acetazolamide-induced vasodilation) and coronary SVD (reduced heart perfusion during adenosine-induced vasodilation). The researchers anticipate that patients with type 2 dabetes have reduced perfusion capacity of the brain and heart correlating to reduced cognition and cardiorespiratory fitness (VO2-max).

Comparison of Differencens in VO2-max, Perfusion of the Heart and Brain and Cognitive Performance Between Patients with Type 2 Diabetes and Healthy Age Matched Controls.

In the aging population, ischemic heart disease, stroke and dementia are increasingly prevalent. Diagnosis and treatment of the former two i.e., large-vessel coronary heart disease and endovascular thrombectomy of the brain in relation to stroke have improved significantly. Yet, the majority of elderly patients with ischemic heart disease do not have large-vessel heart disease and it seems that small vessel disease (SVD) may explain a large fraction of these cases as well as the cardiovascular morbidity in the elderly. Hence, the current development in diagnostics and treatments of ischemic heart disease does not address the most common subtype of ischemic disease seen in elderly patients. It has been suggested that SVD is part of a multisystem disorder and several systematic reviews have addressed the hypothesis of a potential link between small vessel disease of the heart, brain, and kidneys. Cerebral SVD is prevalent in the aging population causing cognitive impairment, dementia, and an increased risk of stroke, and cerebral hypoperfusion is an acknowledged cause of vascular dementia and a possible cause of Alzheimer's disease. Further, cognitive impairment within multiple cognitive domains is highly prevalent in heart failure and is associated to an increased risk of dementia. The link between heart failure and dementia may be due to multisystem SVD, although a direct link between the two is possible. Among other known risk factors such as age, hypertension, and female sex, diabetes is a major cause of SVD and is linked to coronary heart disease as well as cognitive impairment. The diagnosis of cerebral SVD relies on MRI detecting infarctions, haemorrhages, microbleeds and ischemic white matter changes, i.e. Fazekas score. In contrast, perfusion PET is used to image myocardial perfusion in patients with coronary SVD; and coronary SVD is recognized as a part of the pathophysiology in angina, coronary artery disease, and heart failure. Perfusion PET before and after adenosine-induced vasodilation allows for measuring, the myocardial flow reserve (MFR), i.e. perfusion capacity, which in the absence of regional perfusion defects, is a measure of coronary SVD. Prof. Eva Prescott have recently shown that reduced MFR obtained by 82Rb PET is a strong predictor of future microvascular events and all-cause mortality. Exercise is well known to improve cognitive health but professor Carl-Johan Boraxbekk has shown that the effect on cognitive performance may be dependent on the initial cerebrovascular status, as patients with moderate to severe white matter changes did not improve after a 6 months physical activation intervention in contrast to patients with mild changes. Yet, it is possible to improve brain function in diabetic patients through either dietary or exercise interventions. Systemic SVD is measured as cerebral SVD (reduced brain perfusion during acetazolamide-induced vasodilation) and coronary SVD (reduced heart perfusion during adenosine-induced vasodilation). The researchers anticipate that patients with type 2 dabetes have reduced perfusion capacity of the brain and heart correlating to reduced cognition and cardiorespiratory fitness (VO2-max).