Do you consider a severe ICA stenosis (70-99% narrowing per NASCET criteria) symptomatic if a lacunar stroke attributable to small vessel disease occurs in the perforating arteries (e.g. lenticulostriate) downstream from the stenosis?

This is a great question and I do not think there’s a definite answer for it. Indeed a small portion of subcortical lacunar infarcts is due to proximal embolism. On the other hand, lacunar infarcts and ECAD share multiple risk factors. Evidence of prior embolic-looking lesions, carotid plaque morphology with soft components, HITS on TCD, and concerns for future hypotensive episodes would argue in favor of the intervention (preferably CEA). Even after the intervention, would apply maximal cerebrovascular risk control.