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NCT05491980
The purpose of this study is to create a state-wide biorepository and resource center for cerebrovascular diseases in Florida, which will include collecting medical history information and blood from subjects affected by cerebrovascular disease. The information and blood samples collected may be used in future research for the study of cerebrovascular disease and to learn about, prevent or treat other health problems.
NCT05997732
The main purpose of this interventional study is to examine differences in resting blood pressure control between healthy males and females. The main questions it aims to answer are: 1. Are there sex differences in the communication between the sympathetic nervous system (also known as the "fight or flight" response) and peripheral blood vessels (which influence systemic blood pressure)? 2. What is the role of specific vascular receptors that respond to sympathetic signals, and is it different between males and females? Participants will complete one study visit of approximately 3 hours where they will: * Have a blood sample taken to measure circulating sex hormone and sympathetic transmitters. * Receive very small doses of medications commonly used to adjust blood pressure through an artery in their arm. The effects of these medications will be short-acting and localized to the forearm. * Have their sympathetic nervous activity directly measured through two very small needles (similar to acupuncture needles) in the side of their leg. * Have their blood pressure and heart rate recorded, and forearm blood flow measured using ultrasound.
NCT04436731
Patients with sleep apnea are at increased risk of developing cardiovascular disease - with women at potentially greater risk than men. Contributing mechanisms are not well understood, but may be related to how women respond to low oxygen and, given over 70% of patients with sleep apnea are obese, the impact of obesity. This project seeks to increase our understanding of mechanisms that may contribute to sex differences in the cardiovascular response to low oxygen with the hope that this knowledge will improve the efficacy of current therapies and support the discovery of novel therapeutics.
NCT04580238
Post stroke headache occurs in approximately 10-23% of all stroke patients. Its onset is shortly after experiencing a stroke, or stroke like event, and persists for at least three months. These headaches have features which resemble migraine or occur in people who have a previous history of migraine that was once infrequent. Botox is a treatment that is currently approved for the treatment of chronic migraine, that is migraine headaches occurring for at least 15 days a month for at least 3 months. Given the clinical similarity in character and frequency of post stroke headache and migraine, and the fact that stroke affects structures like the blood vessels in the brain that are also affected in migraine, this study is to investigate the possible role that Botox would have in the treatment of Post-Stroke Headache.
NCT05525416
This study aims to investigate sex differences in blood pressure control associated with exposure to acute hypoxia (low oxygen), and short term acclimatization to hypoxia at high altitude.
NCT03255187
This study aims to evaluate whether dietary supplementation with fish oil can protect against the cardiopulmonary alterations linked to air pollution
NCT04463212
Reversible Cerebral Vasoconstriction Syndrome (RCVS) is a syndrome described at the end of the 20th century. Generally, it has a benign course. It is revealed by acute headaches, in different circumstances such as sexual activity, physical exertion or emotional disturbances. But, in few cases, it might be complicated by seizure, stroke and subarachnoid haemorrhage. The diagnosis is confirmed on radiological examination, which shows diffuse cerebral vasoconstriction of brain vessel. It calls reversible because at three month, vasoconstriction disappears. Most cases occur during post partum or after serotoninergic/adrenergic drug use. The pathophysiology is unknown but a transient disturbance in the control of cerebrovascular tone by sympathic hyperactivity and/or endothelial dysfunction are suspected. The assessment of endothelial dysfunction in brain is possible with transcranial doppler. Chen et al. showed an impairment of vasodilatation post apnea induced called BHI on RCVS subjects compared with healthy control. BHI is a reflect of endothelial function in brain. Currently, investigators do not know if endothelial dysfunction occurred only in brain or if it may occur in systemic vessel. Some case reports talk about systemic complication such as kidney infarct or hepatic arterial vasospasm so a systemic vascular dysfunction may be suspected. In this study, researchers will study systemic endothelial function by measure of the pulse wave velocity during RCVS and after its recovering at 3 months, and compare it at healthy controls.
NCT05244694
The purpose of this project is to determine if hyperinsulinemia attenuates sympathetic nervous system-mediated vasoconstriction in the human leg.
NCT05001048
This study aims to investigate sex differences in blood pressure control associated with exposure to acute hypoxia (low oxygen), and short term acclimatization to hypoxia at high altitude.
NCT05146089
The overall goal of this project is to better understand the effect of intermittent hypoxia (IH) on sympathetic neuronal discharge patterns in humans, as well as mechanisms that mediate persistent sympathoexcitation with IH.
NCT04998253
Summary Currently, the COVID-19 pandemic has overtaken health systems worldwide, exceeding the capacity of intensive care units. In addition to this, countries such as the United States have reported a decrease in the supplies of drugs such as Propofol and Midazolam (traditionally used as sedatives in patients with invasive mechanical ventilation), so in the absence until now of a specific treatment against SARS-COV-2 virus, improving the support strategies in patients in the severe spectrum of the disease Acute Respiratory Distress Syndrome (ARDS) is a priority. Given the global state of emergency due to COVID-19, the use of sevoflurane has the potential to mitigate the shortages of sedative drugs, promote the recovery of patients with ARDS, and potentially reduce mortality. A study will be conducted to evaluate the effect of sevoflurane as inhalation sedation in patients with ARDS secondary to SARS-COV2 compared to the standard. The primary objective of the study is to assess the difference in oxygenation, for which the calculation of the partial pressure of arterial oxygen to fractional inspired oxygen concentration ratio (PaO2 / FiO2) will be used at 24 and 48 hours. Also, the effect of the possible attenuation or inhibition of hypoxic pulmonary vasoconstriction will be evaluated by hemodynamic monitoring with a pulmonary artery catheter and transthoracic echocardiography and its possible effect on the right ventricle. Outcome: we expect an improvement in oxygenation and consequently a reduction in the days of invasive mechanical ventilation, stay in the intensive care unit (ICU) and hospital. In addition to evaluating its possible anti-inflammatory effect and probably establishing a safe and effective alternative and possibly with greater benefits compared to standard intravenous sedation.
NCT03972683
The overall goal of this study is to address fundamental questions regarding how the molecule acetylcholine interacts with the sympathetic nervous system to regulate blood flow and oxygen delivery to working skeletal muscle in young and older adults. With advancing age, blood vessels supplying active muscle lose their ability to override sympathetic constriction, which limits delivery of oxygen and results in fatigue. Findings from these studies will serve as the foundation for new strategies to improve regional blood flow regulation in older adults and clinical populations, which will increase quality of life and help to preserve functional independence.
NCT03847779
Microcirculatory flow is subject to cyclic changes under the influence of heart rate, respiration, myogenic activity, neurogenic factors and endothelial factors. Microcirculatory oscillations (vasomotion) contribute significantly to tissue perfusion. Vasomotion analysis allowed to discriminate normoglycemic subjects, prediabetic subjects and diabetic subjects. Furthermore, changes in vasomotion can precede the emergence of global signs of microangiopathy complications in type 2 diabetes. In fact, few studies reported impaired vasomotion in type 2 diabetes with peripheral neuropathy. Vasomotion analysis after vasodilator (6-min walking test and hyperthermia) and after vasoconstrictor (foot lowering) stimulus could be an effective diagnostic tool to sharpen the diagnostic. Objectives and Methodology: to study vasomotion at baseline and after exercise, hyperthermia and foot lowering within 3 groups of patients: diabetic without peripheral neuropathy, diabetic with subclinical peripheral neuropathy and diabetic with peripheral neuropathy and one group of sex- age- and body mass index-matched healthy control subjects. All the subjects will benefit from a clinical, anthropometric, level of physical activity and biological evaluations. Type 2 diabetes participants will benefit from neuropathy evaluation. In addition, cutaneous microcirculation (perfusion and vasomotion) by means of Laser Doppler Flowmetry and Laser Speckle Imaging will be recorded at rest and after different stimuli (exercise, hyperthermia and foot lowering).
NCT03842046
The aim of this double-blind randomized study will be to compare a fixed-rate prophylactic noradrenaline infusion to a fixed-rate prophylactic phenylephrine infusion during elective cesarean section under combined spinal-epidural anesthesia
NCT03758365
The objective of this trial is to compare the vasoconstriction potential
NCT03150524
This is a randomized clinical trial of short-acting nimodipine versus twice daily extended release verapamil to treat patients presenting with Reversible Cerebral Vasoconstriction Syndrome (RCVS).
NCT03509701
Among patients with thunderclap headache who were admitted to the four participating hospitals, who has diffuse segmental vasoconstriction on CT angiography or MR angiography will be eligible for the study. Participants who meet the definition of RCVS will be enrolled as the case-patients and others will be enrolled as control-patients. The RCVS group will be defined when two or more neurologists agree by the clinical features and angiographic findings. The result of tests for varicella zoster virus titer will not be opened to neurologists until the end of the study. For case and control patients, tests for varicella zoster virus infection are (1) Pre-existing virological markers (ex. VZV-IgG, IgM, and VZV PCR in CSF or Skin lesion if present) (2) VZV-specific cell mediated immune response (CMI) at the time of admission and one month later (3) VZV in blood measured by quantitative test of viral load with real-time PCR and digital PCR for latent viral load (4) Quantitative test of viral load with real-time PCR in saliva at time of admission and one month later. Reactivation or infection of VZV of patients with RCVS and controls will be compared.
NCT03204110
Reversible cerebral vasoconstriction syndrome (RCVS) is a clinico radiological entity characterized by severe headaches (associated or not with neurological complications) during one to 3 weeks, associated with a characteristic 'string and beads' appearance on cerebral arteries, which resolves spontaneously in 3 months. The pathway is unknown. At early stage of the disease (at the first medical consultation) cerebral arterial abnormalities which are necessary for diagnosis are identified in only 20% of patients (brain magnetic resonance imagery (MRI) ,CT scan angiography), appearing with a delay on 2th or 3rd week after the first severe headache.. Retinal artery network is considered to be a window on brain microvasculature by sharing the same embryologic origin and physiopathology. A retinal arteriolar examination at early stage of RCVS could provide non invasively early clue to confirm diagnosis by identifying anatomical change and /or functional abnormalities at the microvascular level, whereas large cerebral artery abnormalities are still normal.
NCT02238028
An intervention study to assess the short-term cardiovascular effects of reducing personal air pollution exposure by wearing particulate filtering respirators.
NCT01992939
This is the second part of a research study in order to determine if using a specialized pulse oximetry probe with external heat pack will help obtain oxygen saturation (SaO2) and heart rate (HR) during monitoring for patients with peripheral vascular disease (PVD), vasoconstriction, and hypothermic extremities. The inability to obtain accurate SaO2 and pulse readings can lead to misdiagnosis, incorrect treatment, or procedures to be canceled. SaO2 and pulse readings are important to maintain patient stability during diagnostic testing, surgical procedures and monitoring while in critical care areas. Changes in SaO2 and pulse are important to monitor in order to be able to compensate for any decrease in patient oxygen saturations during hemodynamic monitoring. The primary aim of this study is to determine if using a specialized pulse oximetry probe with external heat pack will improve oxygenation readings in order to obtain SaO2 and pulse readings in patients with PVD, vasoconstriction, and hypothermic extremities as compared to readings obtained from an arterial blood gas. The hypothesis is using a specialized pulse oximetry probe with external heat pack will help obtain more accurate pulse oximetry readings consistent with values obtained with an arterial blood gas.