A cross-sectional feasibility study of neurovascular ultrasound in Malawian adults with acute stroke-like syndrome

Abstract

Background In sub-Saharan Africa, there is a dearth of epidemiologic data on the burden of cerebral atherosclerosis. This is explained by the limited availability and the high cost of standard vascular imaging techniques. Neurovascular ultrasound is portable, cheaper and non-invasive and could, therefore, represent a reasonable alternative to fill this knowledge gap. We explored the feasibility of neurovascular ultrasound in Malawian adults with acute stroke-like syndrome to inform the design of future large stroke studies comparing its diagnostic performance to that of gold standard vascular imaging techniques in sub-Saharan Africa. Methods We enrolled consecutive patients diagnosed with acute stroke-like syndrome based on the World Health Organization definition. Clinical and demographic data were recorded, and a comprehensive neurovascular ultrasound was performed. Fisher's exact and Kruskal-Wallis tests were used to study the relationship between atherosclerosis and potential risk factors. Results Sixty-six patients were enrolled (mean age: 58.7 years). The frequency of extracranial atherosclerosis was 39.4% (n = 26, 95% CI: 28.6-52.2). There were 12 patients with abnormal carotid intima media thickness (18.2%, 95% CI: 9.8-29.6) and 14 patients with a carotid plaque (21.2%, 95% CI: 12.1-33.0). The frequency of intracranial atherosclerosis was 19.2% (95%CI: 6.6-39.4) in 26 patients with successful transcranial insonation. Hypertension

Carotid Doppler findings among patients admitted with stroke in two tertiary care facilities in Uganda: A Hospital-based Cross-sectional Study

“…We recommend future researchers to use a constant cutoff for comparability of study ndings or present the various percentages of CIMT abnormalities based on the various cutoffs. A Malawian study revealed the prevalence of thickened carotid intima thickness to be 18% which is slightly lower than in the present study [39]. The difference could be due to our study having a higher mean age of participants (62 years), a higher prevalence of hypertension (88%) compared to the Malawian study.…”

“…Studies in sub-Saharan Africa involving high risk cerebrovascular patients document a carotid plaque prevalence of between 15-30 [20,21]. In a meta-analysis involving 64 studies, high risk echolucent plaques were present in high risk patients with carotid stenosis [39].…”

Stroke in Africa: profile, progress, prospects and priorities

“…However, a study in participants with hypertension and stroke in Nigeria found that carotid intima media thickness was a sensitive indicator of cardiovascular phenotype and had a stronger association with stroke than popular cardiovascular risk calculators that are used to estimate the time-related risk of cardiovascular disease 149 , 150 . A more recent study of individuals diagnosed with acute stroke-like syndrome in Malawi reported that 39.4% had extracranial atherosclerosis and 19.2% had intracranial atherosclerosis 151 . Post-mortem studies undertaken ~40 years apart also identified a temporal increase in the frequency and severity of cerebral atherosclerosis among Nigerian Africans in tandem with the overall rise in the burden of cardiovascular disease and stroke occurrence 152 – 154 .…”