Rufus Akinyemi

Stroke injury, cognitive impairment and vascular dementia ☆

The global burden of ischaemic strokes is almost 4-fold greater than haemorrhagic strokes. Current evidence suggests that 25–30% of ischaemic stroke survivors develop immediate or delayed vascular cognitive impairment (VCI) or vascular dementia (VaD). Dementia after stroke injury may encompass all types of cognitive disorders. States of cognitive dysfunction before the index stroke are described under the umbrella of pre-stroke dementia, which may entail vascular changes as well as insidious neurodegenerative processes. Risk factors for cognitive impairment and dementia after stroke are multifactorial including older age, family history, genetic variants, low educational status, vascular comorbidities, prior transient ischaemic attack or recurrent stroke and depressive illness. Neuroimaging determinants of dementia after stroke comprise silent brain infarcts, white matter changes, lacunar infarcts and medial temporal lobe atrophy. Until recently, the neuropathology of dementia after stroke was poorly defined. Most of post-stroke dementia is consistent with VaD involving multiple substrates. Microinfarction, microvascular changes related to blood–brain barrier damage, focal neuronal atrophy and low burden of co-existing neurodegenerative pathology appear key substrates of dementia after stroke injury. The elucidation of mechanisms of dementia after stroke injury will enable establishment of effective strategy for symptomatic relief and prevention. Controlling vascular disease risk factors is essential to reduce the burden of cognitive dysfunction after stroke. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

Frontal white matter hyperintensities, clasmatodendrosis and gliovascular abnormalities in ageing and post-stroke dementia

White matter hyperintensities are associated with post-stroke cognitive dysfunction, but the underlying mechanisms are unclear. Chen et al. provide evidence from human and experimental studies that clasmatodendrosis – a marker of irreversible astrocyte damage – and gliovascular abnormalities are increased in the frontal white matter of subjects who succumb to vascular dementia.

Spectrum of heart diseases in a new cardiac service in Nigeria: An echocardiographic study of 1441 subjects in Abeokuta

BackgroundEchocardiography is a non-invasive, relatively cheap and useful imaging technique for the evaluation of cardiac diseases. The procedure has reliable levels of accuracy.Echocardiography commenced at the Federal medical centre Abeokuta on September 9, 2005.The aim of this study is to report our experience with the procedure, and to define the clinical cases seen in our setting.MethodsThis is a retrospective analysis of a prospectively collected data. Echocardiography was performed using Aloka SSD 1,100 echocardiograph equipped with 2.5–5.0 MHz transducerResultsDuring the period of 18 months under review (September 2005–February 2007), 1629 procedures were performed. The reports of 188 echocardiograms were excluded due to poor echo-window, repeated procedure or incomplete report. 1441 reports were reviewed for demographic parameter, indications for the procedure and the main echocardiographic diagnoses.The mean age of the 1441 individuals studied was 54 +/- 14.3 years (15–90). There were 744 men and 697 women. Eight hundred and seventeen subjects (56.7%) had hypertensive heart disease, 53 subjects (3.7%) had rheumatic heart disease while 44(3.0%) had dilated cardiomyopathy. Pericardial diseases, cor-pulmonale, ischaemic heart disease, congenital heart diseases, diabetic heart disease, thyroid heart disease, sickle cell cardiopathy were present in 26(1.8%), 23(1.6%), 9(0.6%), 6(0.4%), 6(0.4%), 6(0.4%), 1(0.1%), and 1(0.1%) respectively. Four hundred and forty nine (31.2%) subjects had normal study.ConclusionHypertensive heart disease was found to be the most prevalent cardiac condition in this study. The relatively frequent diagnoses of rheumatic heart disease, cardiomyopathies and pericardial diseases reflect the impact of infections and infestations on the cardiovascular health of adult Nigerians.We suggest that prevention and treatment of cardiac diseases in our setting should among other things focus on blood pressure control and early treatment of infections causing heart diseases.

Profile and determinants of vascular cognitive impairment in African stroke survivors: The CogFAST Nigeria Study

OBJECTIVE Sub-Saharan Africa faces a potential epidemic of non-communicable diseases including stroke and dementia but little is known about the burden of stroke-related cognitive dysfunction. We assessed the baseline profile and factors associated with vascular cognitive impairment (VCI) in stroke survivors participating in the Cognitive Function After STroke (CogFAST) Nigeria Study. METHODS We recruited 217 subjects (>45 years old) comprising 143 stroke survivors and 74 demographically matched stroke-free healthy controls. We obtained demographic, clinical and lifestyle information and assessed the cognitive status of the subjects at baseline three months after stroke. Standard neuropsychological tests included the Vascular Neuropsychological Battery, which assessed executive function/mental speed, memory, language, and visuospatial/visuoconstructive functioning. Cognitive impairment and dementia were defined based on the AHA/ASA VCI guidelines and the DSM IV criteria. RESULTS Among the stroke survivors (mean ag e= 60.4+9.5 years, 43.4% female, mean number of years of education = 9.4+5.6 years, median modified Rankin score = 2), 57 (39.9%) had cognitive impairment no dementia while 12 (8.4%) were demented at baseline. Multivariate analysis revealed that older age [OR = 1.05 (1.00-1.09)], low education [OR = 5.09 (2.17-11.95)], pre-stroke cognitive decline [OR = 4.51 (1.20-16.88)] and medial temporal lobe atrophy [OR = 2.25 (1.16-4.35)] were independently associated with cognitive dysfunction whereas pre-stroke daily intake of fish [p = 0.022, OR = 0.39 (0.15-0.89)] was inversely associated. CONCLUSIONS These results suggest a high frequency of early VCI in older Nigerian stroke survivors. Apart from aging, associated neurodegeneration and cognitive decline, educational level and pre-stroke diet particularly fish consumption were identified as modifiable factors. This emphasizes the vital role of education and healthy nutrition in building reserves to ameliorate cognitive dysfunction after stroke.

Multilingual Validation of the Questionnaire for Verifying Stroke-Free Status in West Africa

Background and Purpose— The Questionnaire for Verifying Stroke-Free Status (QVSFS), a method for verifying stroke-free status in participants of clinical, epidemiological, and genetic studies, has not been validated in low-income settings where populations have limited knowledge of stroke symptoms. We aimed to validate QVSFS in 3 languages, Yoruba, Hausa and Akan, for ascertainment of stroke-free status of control subjects enrolled in an on-going stroke epidemiological study in West Africa. Methods— Data were collected using a cross-sectional study design where 384 participants were consecutively recruited from neurology and general medicine clinics of 5 tertiary referral hospitals in Nigeria and Ghana. Ascertainment of stroke status was by neurologists using structured neurological examination, review of case records, and neuroimaging (gold standard). Relative performance of QVSFS without and with pictures of stroke symptoms (pictograms) was assessed using sensitivity, specificity, positive predictive value, and negative predictive value. Results— The overall median age of the study participants was 54 years and 48.4% were males. Of 165 stroke cases identified by gold standard, 98% were determined to have had stroke, whereas of 219 without stroke 87% were determined to be stroke-free by QVSFS. Negative predictive value of the QVSFS across the 3 languages was 0.97 (range, 0.93–1.00), sensitivity, specificity, and positive predictive value were 0.98, 0.82, and 0.80, respectively. Agreement between the questionnaire with and without the pictogram was excellent/strong with Cohen k=0.92. Conclusions— QVSFS is a valid tool for verifying stroke-free status across culturally diverse populations in West Africa.

Neurogenomics in Africa: Perspectives, progress, possibilities and priorities.

The understanding of the genetic basis of neurological disorders has grown rapidly in the last two decades. Despite the genomic heterogeneity within African populations, large-scale candidate gene or linkage and exome studies are lacking. However, current knowledge on neurogenetics in African populations is limited and geographically very uneven. Isolated reports indicate the existence of autosomal dominant or recessive conditions incorporating cerebrovascular, movement, neuromuscular, seizure and motor neuron disorders in Africans. In addition, few African families with neurodegenerative disorders associated with dementia have been characterized in North, West and South Africa. The current insurgency in genomic research triggered by among others the Human Health and Heredity (H3) Africa Initiative indicates that there are unique opportunities to advance our knowledge and understanding of the influence of genomic variation on the pattern, presentations and prognosis of neurological disorders in Africa. These have enormous potential to unmask novel genes and molecular pathways germane to the neurobiology of brain disorders. It would facilitate the development of novel diagnostics, preventative and targeted treatments in the new paradigm of precision medicine. Nevertheless, it is crucial to strike a balance between effective traditional public health strategies and personalized genome based care. The translational barriers can be overcome through robust stakeholder engagement and sustainable multilevel, multigenerational and multidisciplinary capacity building and infrastructural development for genomic medicine in Africa.

Stroke in Indigenous Africans, African Americans, and European Americans

Background and Purpose— The relative contributions of racial and geographic factors to higher risk of stroke in people of African ancestry have not been unraveled. We compared stroke type and contributions of vascular risk factors among indigenous Africans (IA), African Americans (AA), and European Americans (EA). Methods— SIREN (Stroke Investigative Research and Educational Network) is a large multinational case–control study in West Africa—the ancestral home of 71% AA—whereas REGARDS (Reasons for Geographic and Racial Differences in Stroke) is a cohort study including AA and EA in the United States. Using harmonized assessments and standard definitions, we compared data on stroke type and established risk factors for stroke in acute stroke cases aged ≥55 years in both studies. Results— There were 811 IA, 452 AA, and 665 EA stroke subjects, with mean age of 68.0±9.3, 73.0±8.3, and 76.0±8.3 years, respectively (P<0.0001). Hemorrhagic stroke was more frequent among IA (27%) compared with AA (8%) and EA (5.4%; P<0.001). Lacunar strokes were more prevalent in IA (47.1%), followed by AA (35.1%) and then EA (21.0%; P<0.0001). The frequency of hypertension in decreasing order was IA (92.8%), followed by AA (82.5%) and then EA (64.2%; P<0.0001) and similarly for diabetes mellitus IA (38.3%), AA (36.8%), and EA (21.0%; P<0.0001). Premorbid sedentary lifestyle was similar in AA (37.7%) and EA (34.0%) but lower frequency in IA (8.0%). Conclusions— Environmental risk factors such as sedentary lifestyle may contribute to the higher proportion of ischemic stroke in AA compared with IA, whereas racial factors may contribute to the higher proportion of hypertension and diabetes mellitus among stroke subjects of African ancestry.

Stroke Investigative Research and Education Network Community Engagement and Outreach Within Phenomics Core

Stroke is the leading cause of neurological hospital admissions in sub-Saharan Africa (SSA) and the second leading cause of death globally. The Stroke Investigative Research and Education Network seeks to comprehensively characterize the genomic, sociocultural, economic, and behavioral risk factors for stroke and to build effective teams for research to address and decrease the burden of stroke and other noncommunicable diseases in SSA. One of the first steps to address this goal is to effectively engage the communities that suffer the high burden of disease. The purpose of this article is to describe plans to elucidate information about knowledge, attitudes, beliefs, and practices about stroke and genomics from patients, caregivers, and local leaders, to recruit participation in research activities and dissemination of ongoing results, as well as to facilitate research uptake and impact within the broader communities of scientists, health professionals, policy makers, and others. We describe the (a) study sites and their communities; (b) plans for community advisory boards, focus groups, and surveys; (c) methods for data management in REDCap database; (d) analyses of qualitative data; (e) evaluation of community and public engagement across multiple sites and research teams in SSA and the United States; (f) use of RE-AIM for presentation of evaluation data; and (g) community indicators of success. This is the first of its kind public outreach engagement initiative to evaluate stroke and genomics in SSA, and has implications as a model for assessment in other high–stroke risk populations.

Exploring Overlaps Between the Genomic and Environmental Determinants of LVH and Stroke

Background—Whether left ventricular hypertrophy (LVH) is determined by similar genomic and environmental risk factors with stroke, or is simply an intermediate stroke marker, is unknown. We present a research plan and preliminary findings to explore the overlap in the genomic and environmental determinants of LVH and stroke among Africans participating in the Stroke Investigative Research and Education Network (SIREN) study. Methods—SIREN is a transnational, multi-centre study involving acute stroke patients and age, ethnicity and sex-matched controls recruited from 9 sites in Ghana and Nigeria. Genomic and environmental risk factors and other relevant phenotypes for stroke and LVH are being collected and compared using standard techniques. Results—This preliminary analysis included only 725 stroke patients (mean age 59.1±13.2 years; 54.3% males). Fiftyfive percent of the stroke subjects had LVH with greater proportion among women (51.6% vs 48.4%, p<0.001). Those with LVH were younger (57.9±12.8 vs 60.6±13.4; p=0.006) and had higher mean systolic and diastolic BP (167.1/99.5 mmHg vs 151.7/90.6 mmHg, p <0.001). Uncontrolled blood pressure (BP) at presentation was prevalent in subjects with LVH (76.2% vs 57.7%; p <0.001). Significant independent predictors of LVH were age, < 45 years (AOR =1.91, 95% CI: 1.14 to 3.19), female gender (AOR = 2.01; 95% CI:1.44 to 2.81), and diastolic BP > 90mmHg (AOR = 2.10; 95% CI:1.39 to 3.19, p <0.001). Conclusion—The prevalence of LVH was high among stroke patients especially the younger ones suggesting a genetic component to LVH. Hypertension was a major modifiable risk factor for stroke as well as LVH. It is envisaged that the SIREN project will elucidate polygenic overlap (if present) between left ventricular hypertrophy and stroke among Africans, thereby defining the role of LVH as a putative intermediate cardiovascular phenotype and therapeutic target to inform interventions to reduce stroke risk in populations of African ancestry. Corresponding Author: Mayowa O. Owolabi, MBBS, MSc, DM, FMCP, Department of Medicine, University College Hospital, Ibadan, Nigeria, West Africa., Phone: +234 802 077 5595, mayowaowolabi@yahoo.com. Publishers Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. HHS Public Access Author manuscript Glob Heart. Author manuscript; available in PMC 2018 June 01. Published in final edited form as: Glob Heart. 2017 June ; 12(2): 107–113.e5. doi:10.1016/j.gheart.2017.01.001. A uhor M anscript

Cardiac emergencies in a Nigerian hospital: Data from the Abeokuta heart disease registry

Background: The emergency room is most often the gateway to many hospitals and health facilities. The spectrum of medical disease (including cardiac disease) in this department is often a reflection of the pattern of diseases in the immediate environment. Objective: The aim of this study therefore is to describe the spectrum of cardiac diseases presenting at the emergency room of Federal Medical Centre, Abeokuta, Ogun State, Nigeria. Methods: This was a retrospective analysis of a prospectively acquired data over a period of 24 months (January 2006 to December 2007) and was conducted at the Emergency Department of the Federal Medical Centre, Abeokuta, Nigeria. All cardiac cases presenting to the centre during the period of the study were consecutively captured using structured and uniform case report form. Data collected include the patient′s bio data, data of admission as well as clinical diagnosis. Disease classifications were based on International Classification of Disease-10. Results: A total of 414 patients classified as cardiac presented to the medical emergency room between January 2006 and December 2007. This constituted 17.4% of all medical cases seen at this department during this period. There were 208 men (50.2%) and 206 women (49.8%). The mean age of all the subjects was 54.7±14.6 (range 15-90 years). Majority of the patients (48.5%) were between the ages of 40 years and 59 years. The most common reasons for cardiac related admissions include severe hypertension, acute heart failure or acute left ventricular heart failure. Conclusions: Cardiac related admissions in the emergency room in Abeokuta are related to hypertension and its complication-heart failure. Prevention as well as management of cardiac diseases should be tailored to hypertension and its associated risk factors. Facilities for management of hypertension and heart failure should be provided in our emergency room.