Clinical Research Directory

Impact of COVID-19 Vaccines on Cerebrovascular Health

Safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may reduce the transmission of and achieve population immunity against the COVID-19 pandemic, which accounted for more than 3.75million deaths worldwide. With World Health Organization's (WHO) effort on ensuring equitable access to COVID-19 vaccines, vaccination rate may increase in the near future. On the other hand, vaccination hesitancy has emerged as a major hindrance on the global vaccination campaigns in certain areas due to safety concerns, social factors, and public health policies. For instance, a recent survey conducted in Hong Kong showed a low vaccine acceptance rate of 37%. Long-term safety concerns and post-vaccination events relayed by the social media maybe reasons for vaccination hesitancy. Among which, cerebrovascular accidents (CVA) after vaccination were one of the most frequently reported post-vaccination events. These reports ranged from ischemic strokes in elderly patients with multiple cardiovascular co-morbidities, to hemorrhage strokes in otherwise "young-and-fit" adults. While many of these events were investigated by the COVID-19 immunization expert committee, an important premise to address the apprehension of CVA after vaccination is the provision of evidence-based information of the impact of COVID-19 vaccines on brain health. In this prospective, longitudinal, observational study, we aim to elucidate the relationship between COVID-19 vaccines and cerebrovascular health in healthy citizens in a population-based cohort.

CUHK Brain Health Longitudinal Study

The goal of this study is to develop a large longitudinal cohort of individuals diagnosed with or at high risk for brain diseases (both neurological and psychiatric in nature), in order to identify risk factors that contribute to neurological and psychiatric diseases over time. The investigators seek to capture relevant information from medical records, electronically administered questionnaires and follow up phone-based interviews. The investigators expect to eventually have sufficient power from our dataset to examine risk factors for a variety of brain disorders, both individually and in aggregate. Our ultimate goal is to offer scientifically validated ways to preserve and promote brain health by working with our patients' needs and tracking their progress over time.

Cardiac Assessment for Recurrent Stroke Risk Evaluation in Atrial Fibrillation

Background Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting up to 10% of the elderly. Ischemic stroke is the main complication of AF and cardioembolism is one of the leading causes of ischemic stroke, accounting for approximately one third of cases. Oral anticoagulant therapy (OAC) is a cornerstone in stroke prevention in patients with AF. According to randomized controlled trials of direct oral anticoagulants, a residual risk of ischemic stroke of 1-2% per year for so-called "breakthrough stroke" remains, despite adequate intake of OAC. The majority (\>70%) of these breakthrough strokes are cardioembolic in nature and only a minority are related to medication issues (e.g. non-compliance) or other, non-AF related etiologies. Stroke recurrence risk after such a breakthrough stroke markedly increases to 8-9% per year indicating a particularly high-risk situation. Why OAC fails in certain patients, but not in others remains as poorly understood, as does the reason why the subsequent risk of stroke is so high. Current risk stratification tools, such as the widely used CHA2DS2-VA(Sc)-score, fail to predict stroke risk in such a high-risk cohort, as they were intended to guide the initiation of OAC in low to moderate risk patients. In light of new therapeutic strategies currently being investigated, such as percutaneous left atrial appendage occlusion in patients with breakthrough strokes (ELAPSE - NCT05976685) or in AF-patients deemed high-risk (LAAOS IV - NCT05963698), improved risk stratification and characterization of high-risk AF patients is highly warranted. Several clinical factors, such as those reflected in the CHA2DS2-VA(Sc)-score, and especially a high AF-burden are associated with increased risk of cardioembolic stroke. Several cardiac serum biomarkers are thought to be surrogates not only of cardiac function, but also of cardioembolic risk. Reflecting ventricular and atrial wall tension, myocardial injury, oxidative stress and thrombogenicity, elevated NT-proBNP, MR-proANP, high-sensitive Troponin T and D-Dimers have all been associated with cardioembolic stroke in different AF and non-AF populations. As the main location of thrombus formation, the left atrium (LA) and more specifically its appendage (LAA) are of particular interest in the pathogenesis of cardioembolism. Pronounced LA-enlargement, compared to a normal-sized LA, correlates with an increased risk of cardioembolism in AF-patients. As over 80% of thrombi form within the LAA, several LAA-characteristics, such as slower LAA-flow velocity and larger LAA-orifice area have also been demonstrated to be associated with higher stroke risk. Although there is data on each one of these factors, they have only been investigated in low to moderate risk populations, such as AF-patients without prior stroke, OAC-naïve patients, or even within the general population as a whole. Their role in high-risk AF-patients and in breakthrough stroke is unknown. Hypothesis The investigators hypothesize that specific clinical factors, serum cardiac biomarkers and markers of LA- and LAA-morphology and function are associated with breakthrough stroke / OAC-failure and may improve risk stratification. Methods CARE-AF is a single-center, prospective cohort study conducted at the Stroke Center of the Inselspital, University Hospital Bern, Switzerland. Patients with an index ischemic stroke and AF (breakthrough and non-breakthrough cases) will be enrolled. The investigators will collect clinical data, serum cardiac biomarkers and echocardiographic indices of the LA and LAA. All patients will receive standardized annual follow-ups until the end of the study, defined as 12 months after the inclusion of the last participant. The primary endpoint is ischemic stroke or systemic embolism during follow-up. First, in a cross-sectional design, the study will assess the association between serum cardiac biomarkers and echocardiographic indices among patients with breakthrough vs. non-breakthrough stroke as index event, applying multivariate regression models. Second, the investigators will perform a longitudinal analysis assessing the association between the variables mentioned above and breakthrough stroke as index event with the primary endpoint, using multivariate Cox regression models. The study aims to enroll a minimum of 500 patients, which provides sufficient power to detect a clinically meaningful adjusted hazard ratio for recurrent stroke of 1.5 with 80% power at an alpha level of 5%. Conclusion The results of this project will enhance understanding of the role of specific clinical factors, cardiac serum biomarkers and echocardiographic indices in the residual risk of stroke in patients with AF on anticoagulation therapy. They may improve current risk stratification and have the potential to help guide therapeutic decisions in high-risk situations considering evolving therapeutic possibilities.

Anesthesia Techniques, Neuroprotection and Surgical Field in FESS Under Controlled Hypotension

This prospective, randomized controlled trial investigates the effect of four different anesthetic maintenance techniques on surgical field conditions, hemodynamic stability, and neuroprotection during functional endoscopic sinus surgery (FESS) performed under controlled hypotension. Patients are randomly assigned to receive either total intravenous anesthesia with propofol-remifentanil, propofol-remifentanil with adjunct ketamine and magnesium, sevoflurane-remifentanil, or sevoflurane-remifentanil with adjunct ketamine and magnesium. Primary outcomes include serum biomarkers of neuronal injury (S100B and neuron-specific enolase, NSE) measured perioperatively, as well as surgical field visibility and intraoperative bleeding scores. Secondary outcomes include recovery profile and postoperative pain.

PRecisiOn Medicine In StrokE: Evolution of Plasma Brain-Derived Tau in Acute Stroke

The investigators recently identified Brain-derived tau (BD-tau) as a sensitive blood-based biomarker for brain injury in acute ischemic stroke: in patients with acute ischemic stroke, plasma BD-tau was associated with imaging-based metrics of brain injury upon admission, increased within the first 24 hours in correlation with infarct progression, and at 24 hours was superior to final infarct volume in predicting 90-day functional outcome. While informing on the relation of BD-tau with imaging-based metrics of brain injury, this cross-sectional study was restricted to BD-tau assessments upon admission and at day 2 and could not inform on key characteristics of the evolution of plasma BD-tau, including when exactly it starts to rise, how long it continues to rise, and how it is determined by infarct characteristics as well as comorbidities. Here, the investigators aim to assess plasma BD-tau every hour from admission to 48 hours after onset to evaluate the hypothesis that BD-tau rises immediately after onset and plateaus between three and 48 hours after onset.

Prognostic Value of Isolated and Combined Score Aspects in Acute Ischemic Stroke

This study, called TARGET-ASPECT, looks at patients who had a type of stroke called acute ischemic stroke and were treated with clot-busting medicine and a procedure to remove the clot. Even with these treatments, about half of patients don't fully recover. The study aims to see if certain brain imaging scores, especially when combined, can better predict how well patients will recover 90 days after their stroke and if their blood vessels reopen successfully. The study will include 152 patients and last about 9 months. The goal is to find easy and reliable tools that doctors can use to make better treatment decisions.

MIDNOR-STROKE- a Long Term Follow-up Study of Patients With First Ever Ischemic Stroke in Central Norway

Annually 13000 Norwegians experience an ischemic stroke. The number of stroke is anticipated to increase with 50% within 2030 due to a growing number of elderly. Many of them will have severe function deficits and reduced quality of life. The investigators have established a cohort consisting of 800 patients with first time ischemic stroke treated at hospitals in Central Norway. The investigators want to study the incidence and prognostic markers for death, recurrent stroke and severe functional deficits during a period of 10 years after the initial ischemic stroke. The investigators want to focus on the impact of physical functioning, the level of physical activity and use of medication for secondary prevention on the incidence of death, recurrent stroke and severe functional deficits. The investigators are especially interested in the importance of fulfilling the treatment targets for blood pressure and cholesterol and the importance of smoking cessation in stroke survivors. Our objective is to improve todays stroke treatment and achieve a more efficient use of the health resources in order to increase survival after stroke maintaining a good physical and psychological function and quality of life.

Evaluation of Patients Affected by Traumatic and Hypoxic-ischemic Brain Injury

According to the World Health Organization, perinatal asphyxia is the leading cause of severe neurological disabilities and the second leading cause of neonatal death among term infants, with an incidence of 3.94-5.12 per 1,000 live births. Perinatal asphyxia leads to neonatal hypoxic-ischemic encephalopathy, which remains a common cause of neonatal death and long-term disabilities, affecting 1.5-3 per 1,000 live births in developed countries and up to 26 per 1,000 live births in developing countries. This condition is characterized by altered levels of consciousness or manifests with seizures, often associated with difficulties in initiating and maintaining breathing, as well as depression of tone and reflexes. Currently, therapeutic hypothermia is the standard treatment for neonates with moderate to severe hypoxic-ischemic encephalopathy; however, it does not provide complete neuroprotection and is only partially effective. Therefore, new treatments with good therapeutic windows are urgently needed to ensure the best possible preservation of neurological tissue for patients exposed to hypoxic-ischemic insult. Traumatic brain injury is a common cause of morbidity and mortality among children and young adults in developed countries. The incidence of traumatic brain injury has increased in recent years, yet the prognosis for these patients has not substantially changed. In recent studies the key intermediary role of the immune system and neuroinflammation has been proposed to explain the pathophysiology of traumatic brain injury, both in the acute phase and in the long term. Indeed, neuroinflammatory processes can persist for several months, contributing to chronic alterations and accelerating brain aging in patients with post-traumatic brain injury. Currently, therapies that have shown promising results in patients with post-traumatic brain injuries are unfortunately still limited, especially in the context of severe traumatic brain injury. Thus, there is an urgent need for new treatments with a broader therapeutic window that can counteract early and chronic pathophysiological events.

Informative of Surface Electromyography and Prognostic Factors in Assessing the Recovery of Balance and Gait After Stroke

The aim of the biomedical research is to determine the informativeness and prognostic factors of surface electromyography by assessing the probability of recovery of balance and gait parameters in the second stage of rehabilitation of persons with cerebral infarction.

Electrocorticographic Monitoring of Brain Retraction Injury (EMBRI)

A single centre IDEAL Stage 1 feasibility study using novel electrophysiological recording techniques in adult participants undergoing neurosurgery. This is a first in human study, building upon previous preclinical mice experiments. Participants will undergo their planned neurosurgical procedure as normal. In addition to their standard treatment neurophysiological monitoring including an electrocorticography electrode placed on the brain deep to the retractor will be used to monitor for signs of brain retraction injury.

A Feasibility Study for Randomization of Code Stroke Imaging Strategies

The purpose of this study is to test feasibility of a comparative effectiveness framework for acute stroke imaging using prospective electronic health data. This is a prospective, cohort feasibility study of patients presenting to the Emergency Department with suspected acute ischemic stroke. The clinical stroke team will not be blinded to the imaging modality given the nature and purpose of the interventions/imaging. Knowledge of the imaging modality used and the knowledge gained from the resulting data will need to be considered for treatment decisions. Blinding will be maintained for data abstraction and analyses. Analysis will be on an "intent-to-scan" basis and all qualifying patients will be included in their assigned cohort.

Multimodal Investigation of Intracranial Clot Environment

Analysis of peri clot blood collected at the acute phase of stroke in order to understand physiopathological mechanisms involved in the cerebrovascular damage

Study on the Performance of a Machine Learning Algorithm Recognizing and Triaging Large Vessel Occlusions Using Non-contrast CT Scans

The goal of this prospective observational study is to assess the effectiveness and performance of Methinks AI stroke imaging software platform in acute Code Stroke patients, and as a comparator to study sites utilizing existing AI imaging stroke platforms. The main question\[s\] it aims to answer is: • Performance of and outcomes associated with the use of the Methinks AI stroke imaging medical device in real-world clinical practice.

For Patients With Ischemic Stroke, Clinically Study the Effectiveness and Safety of Butylphthalide.

This is a prospective, open, single-arm, the real world of clinical trials. The researchers plan to recruit 300 eligible patients. The main purpose of this study is to evaluate the effectiveness and safety of butylphthalide in the treatment of ischemic stroke, and to establish a population pharmacokinetic model of butylphthalide in elderly patients to explore its blood drug concentration. Correlation with its efficacy and adverse reactions.

Population-based Brest Stroke Registry

The registry is the main objective exhaustive list of cases validated stroke brain on a geographical area defined to calculate an incidence.