A narrative review of the pathophysiology of ischemic stroke in carotid plaques: a distinction versus a compromise between hemodynamic and embolic mechanism

Abstract

Atherosclerotic carotid artery stenosis causes about 10-20% of all ischemic strokes through two main mechanisms: hemodynamic impairment in case of significant stenosis and thromboembolism from an atherosclerotic plaque regardless of the degree of stenosis. The latter is the most frequent mechanism and appear to result from embolization from a vulnerable atherosclerotic plaque or acute occlusion of the carotid artery and propagation of thrombus distally. Downstream infarcts may occur in a territory of major cerebral artery or at the most distal areas between two territories of major cerebral arteries, the so-called watershed (WS), or border zone area. Although WS infarcts, especially deep WS infarct, were historically thought to be due to hemodynamic compromise, the role of microembolism has also been documented, both mechanisms may act synergistically to promote WS infarcts. Routine and more advanced imaging techniques may provide information on the underlying mechanism involved in ipsilateral ischemic stroke. A better understanding of ischemic stroke pathogenesis in carotid stenosis may limit the use of routine non-selective shunt, whose benefit-risk balance is debated, to patients with hemodynamic impairment.After reviewing existing evidence underpinning the contribution of the two mechanisms in downstream ischemic stroke and the various imaging techniques available to investigate them, we will focus on the pathogenesis of WS infarcts that remains debated.

Intracranial Flow Volume Estimation in Patients with Internal Carotid Artery Occlusion

“…Two main pathogenetic mechanisms of ischaemic stroke have been identified: haemodynamic impairment due to malperfusion secondary to the significant stenosis. and thromboembolism from a vulnerable atherosclerotic plaque [7].…”

“…Historically, they were thought to be caused mainly by hypoperfusion; however, nowadays it is believed that haemodynamic impairment and microembolisation may act synergistically [7].…”

Identification of Biomarkers of Autophagy-Related Genes Between Early and Advanced Carotid Atherosclerosis

“… 22 Thromboembolism of carotid atherosclerotic plaque is the most common mechanism leading to ischemic stroke. 23 In addition, old age, male, hypertension, diabetes, frequent smoking, long-term smoking and lack of exercise are all risk factors of carotid atherosclerosis. Hypertension (69.1%), dyslipidemia (26.0%) and diabetes (16.1%) are highly prevalent among carotid atherosclerosis participants.…”

Asymptomatic carotid artery stenosis: a summary of current state of evidence for revascularization and emerging high-risk features

“…Hypoperfusion results from increasing stenosis and a failure of collaterals. 32 Thromboembolism results from exposure of highly thrombogenic necrotic plaque core material following plaque rupture. 33 34 Imaging features that can identify steps in the progression towards plaque rupture or rupture itself are of especial interest.…”

“…These features are means to uncover the risk for development of the two main pathophysiological causes of stroke in carotid stenosis, hypoperfusion and thromboembolism. Hypoperfusion results from increasing stenosis and a failure of collaterals 32. Thromboembolism results from exposure of highly thrombogenic necrotic plaque core material following plaque rupture 33 34.…”