Asymptomatic Carotid Stenosis Is Associated With Circadian and Other Variability in Embolus Detection

Conclusions: Embolism associated with asymptomatic carotid stenosis shows circadian variation with highest rates 4–6 h before midday. This corresponds with peak circadian incidence of stroke and other vascular complications. These and ASED Study results show that monitoring frequency, duration, and time of day are important in ES detection. Introduction Transcranial Doppler (TCD) detected microembolism in the ipsilateral middle cerebral artery (MCA) may help stratify the risk of stroke and other arterial disease complications in persons with advanced (≥60%) asymptomatic carotid stenosis. If so, this technique could lead to improved prevention. However, TCD embolic signal (ES) detection is particularly labour intensive in asymptomatic individuals due to relatively low ES detection rates. Approximately 10% of individuals have at least 1–2 ES detected within 1–2 h of TCD monitoring, with median hourly ES rates among ES-positive arteries of 1–2 (1–3). In the Asymptomatic Stenosis Embolus Detection (ASED) Study, on average one ES was detected for every 6.25 h of TCD monitoring (1). The efficiency of TCD monitoring to identify microembolism could be improved if factors influencing shedding rates, including time of day, were better identified. It is unknown if time of day has a significant influence on detecting microembolism associated with asymptomatic carotid stenosis. However, preliminary data from a cohort of seven symptoma...
Source: Frontiers in Neurology - Category: Neurology Source Type: research