Clinical Research Directory

Biomarkers as Prognostic Factors of Silent, Cerebral Infarctions in Patients Undergoing High-thromboembolic-risk Transcatheter Interventions

Background: The transcatheter interventions with high thromboembolic risk, as transcatheter carotid angioplasty or transcatheter ablation of cardiac arrhythmias are associated with asymptomatic strokes- silent strokes. The silent strokes are cerebral infarctions with small diameter which are diagnosed with computed tomography or magnetic resonance imaging (MRI). Silent cerebral infarctions (SCIs) are associated with neurological deficits, cognitive impairment, high mortality and high risk of dementia. There are biomarkers, as neuron specific enolase (NSE) and neurofilaments (NFLs) which are indicated for the prognosis of these patients. Aim: The aim of this study is the prognostic role of biomarkers NSE and NFLs in patients undergoing high-thromboembolic-risk transcatheter interventions. This study will assess the hypothesis that the level of these biomarkers could predict the development of SCIs and the long-term cognitive impairment. Study type - materials: This study is a prospective, observational study. Patients undergoing highthromboembolic-risk transcatheter interventions will be included in this study. Protocol: All the demographic and clinical characteristics of patients will be recorded. Blood samples will be obtained, 24 hours pre-interventionally and 24 hours post-interventionally. The blood samples will be centrifugated and will be freezed at -80 οC for the measurement of biomarkers. MRI will be conducted 24 hours pre- and postinterventionally. The neurological assessment will be conducted with the use of Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) questionnaires, 24 hours pre-interventionally, 24 hours and 6 months postinterventionally. Outcomes: The primary outcome is the association between level of biomarkers and the development of SCIs in MRI post-procedurally. Secondary outcomes concern the probable association of biomarkers with the cognitive impairment. The data will be assessed with statistical analysis and will be interpreted. The results of this study will be published with the view to create algorithms and prognostic tools for appropriate management of these patients.

Stroke Prevention in Young Adults With Sickle Cell Anemia

Sickle cell disease (SCD) is the most common genetic disease, affecting about 25 million people worldwide. Approximately 150,000 Nigerian children are born each year with sickle cell disease (SCD), making it the country with the largest burden of SCD in the world. Recent advancements in care for children with SCA have translated into improved survival of children in both high and low-resource settings. However, more complications of SCD are seen in those who survive to adulthood. Silent cerebral infarcts (SCI) and strokes are among the most devastating complications of SCD, affecting 40% and 10% of children, respectively. The overall goal of this study is to extend the Investigator's successful capacity-building effort in the assessment of neurological morbidity in children with SCD living in northern Nigeria (Kano) to young adults with SCD living in the same region. About 50% of all adults with SCD live in Nigeria. Despite the high prevalence of SCD in Africa, the neurological morbidity is not well characterized, limiting opportunities for primary and secondary stroke prevention strategies. At least 50% of young adults with sickle cell anemia (SCA), the most severe form of the disease, will have SCIs and an estimated 10% will have strokes, based on studies in high-resource settings. In high-resource settings, screening for abnormal transcranial Doppler (TCD) velocities in children with SCA, coupled with regular blood transfusion has resulted in a 92% reduction of relative risk for strokes. Despite this effective strategy, regular blood transfusion therapy does not seem sustainable in sub-Saharan Africa due to shortages and the risk of transfusion transmissible infections. Additionally, there is a lack of evidence-based stroke prevention strategies in young adults with SCA, either in the high-income or in low-resource settings. Based on the foregoing, the Investigators propose to determine the prevalence of neurological injury (overt stroke, transient ischemic attacks, and silent cerebral infarcts) in young adults at the transition age from 16-25 years. The Investigators will also, for the first time, assess conventional risk factors of stroke in the general population to determine whether a different prevention strategy is required to reduce the incidence of neurological injury in this high-risk population.

Prevalence of Attributable Etiology and Modifiable Stroke Risk Factors in Patients With Covert Brain Infarctions

The CBI registry is a prospective, interdisciplinary, multimodal observational registry of patients with covert brain infarction. Methods: A standardized workup in analogy to manifest ischemic stroke including cerebral MRI, long-term rhythm monitoring (3 x 7 days ECG), echocardiography, laboratory work-up and risk factor assessment as well as noninvasive angiography of the cervical and intracranial arteries will be performed.

Incidence of Silent Atrial Fibrillation in Patients With Clinically Silent Brain Ischemic Lesions

Arterial Fibrillation (AF) is well-recognized as a cause for cryptogenic Acute Ischemic Stroke (AIS) and is associated with Silent Brain Infarction (SBI). However, the role of AF in the formation of lesions (SBIs) is less well established than its role in AIS and needs clarification. The investigators hypothesize that continuous rhythm monitoring will yield a similar incidence of AF diagnosis in patients with SBI as compared to patients with cryptogenic AIS. The primary objective is to assess the cumulative incidence of AF diagnosis at 24 months in patients with SBI.