Stroke incidence in Indigenous, minority populations: a review of methods for studying stroke in Aboriginal and Torres Strait Islander Australians

Declining worldwide or national stroke incidence rates are not always mirrored in disadvantaged, minority populations. Logistical barriers exist for effective measurement of incidence in minority populations; such data are required to identify targets for culturally appropriate interventions. In this comparative review, we aimed to examine whether “gold-standard” methodologies of stroke incidence studies are most effective for minority populations. We compared three studies of stroke incidence in Aboriginal Australians, each using different methodologies of case ascertainment. In Study 1, “gold-standard” population-based methods were used, while in Study 2, a retrospective hospital-based cohort design was utilized, and in Study 3, whole-of-population linked hospital and mortality data was employed. Study 1 captured both in-hospital and out-of-hospital stroke events but had a small sample size for Aboriginal patients. Study 2 provided a larger sample size while still allowing for clinical and radiological subtyping of stroke but was subject to selection bias and was limited to hospitalized cases. Study 3 had a large sample size and allowed for subgroup analysis, though lacked clinical adjudication and had large proportions of ‘undetermined stroke'. Despite diagnostic imprecision, we recommend a paradigm shift in measuring stroke incidence in Indigenous, minority populations, favoring the use of whole-of-population data linkage including non-hospitalized stroke deaths, over resource-intensive prospective methods, where more suitable for the target population

The Burden of Stroke in Aboriginal and Torres Strait Islander Australians

Cardiovascular disease, including heart, stroke, and vascular disease, is a significant health problem for many Aboriginal and Torres Strait Islander Australians. However, there is limited information published about stroke in this population. In this thesis, I examined the burden of stroke in the Aboriginal and Torres Strait Islander Australian population, using diverse methods. This research program was developed in response to unmet needs identified by Aboriginal and Torres Strait Islander stakeholders

Double heterozygosity of novel variants found in patients with severe clinical phenotype of cardiovascular disorders

Cardiovascular diseases (CVD) comprise a broad range of disorders of the heart and blood vessels. In this study, we used next-generation sequencing with a panel that includes 174 genes connected to CVD in order to investigate the possible genetic causes that underline some clinical phenotypes and their severity. Two patients were found with double heterozygosity, each carrying one new variant. One patient with supravalvular aortic stenosis has novel ELN: c.890-1G>A and a known variant SCN5A: p.Gly9Val in a heterozygous state, whereas another patient with hypertrophic cardiomyopathy has a heterozygous novel CACNA1C: p.Arg514Gly and a known SCN5A: p.Arg800His variant. This method proved to be useful in determining the mutation status in correlation with the severity of the clinical phenotype and can further clarify cases where the clinical status could not be explained only by single gene mutation detected by standard methods

A narrative review of stroke incidence, risk factors and treatment in Indigenous Peoples of the world

Stroke is the second leading cause of death and the third greatest cause of disability worldwide. In some countries, stroke disproportionally affects Indigenous Peoples, with greater incidence and mortality at younger ages, higher rates of conventional cardiovascular risk factors and lower treatment rates. Worldwide there are 470 million Indigenous Peoples, residing in 90 countries. Analogous to the general health of all populations, the cause of stroke and its outcomes are the result of complex interactions between factors that act at societal, service, and individual levels. Colonisation, including the cultural and material losses associated with it, is a major indirect driver of disparities in lifestyle, biological and other risk factors for stroke in Indigenous Peoples. In addition, structural racism and the inability to access culturally safe education, employment and health care, further contribute to stroke health inequities for Indigenous Peoples globally. In this narrative review we provide an outline of stroke incidence rates, common risk factors for stroke, treatment rates with intravenous thrombolysis and endovascular clot retrieval in adult Indigenous populations in comparison to the non-Indigenous population of the same region. Our objective is to describe the differences that exist between the Indigenous and non-Indigenous populations with stroke in a particular region and discuss potential solutions that support a “strengths-based” approach driven by Indigenous People

Abstract 129: Electromagnetic Portable Brain Imaging For Stroke

Background: Electromagnetic imaging (EMI) is an emerging technology that transmits low energy electromagnetic waves from a ring of transceivers around the head, modified as they pass through abnormal tissue, providing unique signatures for brain pathology. It promises to provide portable, non-ionizing, rapid neuroimaging for prehospital and bedside evaluation of stroke, based on the dielectric properties of the tissue. We aimed to assess the clinical utility of EMI in stroke diagnosis in a pilot study. Methods: In a prospective, observational, open, non-interventional pilot study, patients with imaging-proven ischemic (IS) or haemorrhagic stroke (ICH) within the preceding 48 hours were recruited. Using the EMVision scanner, EMI was performed within 1-24 hours of diagnostic CT or MRI. Images were obtained by processing signals from encircling transceiver antennae contained in an instrumented 18 kg helmet which emit and detect low energy non-ionising signals in the microwave frequency spectrum (0.5-2.0 GHz). Localisation was assessed by determining whether fusion images resulted in target detection in the same quadrant as comparable CT or MRI. Electromagnetic (EM) images were reconstructed by creating maps of the EM wave scattering arising from contrast in electrical parameters between IS or ICH lesions and normal brain. A blinded clinician assessed agreement between regional abnormalities on EMI and CT or MRI scans. Algorithms for distinction between IS and ICH were based on differences in EM transmission, reflection and scattering through brain tissue. Results: Thirty patients were studied, 21 IS and 9 ICH. Mean age was 66.7 years (range 37-87), 57% were female. Mean NIHSS at presentation was 5. Mean time to routine imaging was 5.5 hrs (range 1-48) and to EMI 24 hrs (range 6-60). Nineteen patients (63%) had only CT performed; 11 (37%) had both CT and MRI. EMI differentiated ICH from IS with 93% accuracy and localised the stroke to the correct brain quadrant with 87% accuracy. Conclusion: In this early validation pilot study we show the ability to distinguish between IS and ICH and stroke location within a given brain quadrant. Further developments may produce a valuable imaging tool to assist in prehospital and bedside stroke diagnosis and management. </jats:p