Carotid revascularisation did not improve cognition in asymptomatic stenosis

Design

Substudy of a multicentre phase 3 randomised trial

Population

291 adults with asymptomatic ≥70% carotid stenosis; 51 with reduced baseline cognition

Primary outcome

Change in composite cognitive z score over 1 year

Effect

Adjusted difference −0.15 SD (95% CI −0.54 to 0.24); interaction P = .40

CREST-H was a substudy of the CREST-2 randomised trial, which compared carotid revascularisation (endarterectomy or stenting) plus intensive medical management against intensive medical management alone in asymptomatic carotid stenosis of 70% or more. It tested whether people with reduced cerebral perfusion on the side of the stenosis gained cognitively from revascularisation.

Of 392 enrolled, 291 had complete data and 51 had reduced cognition at baseline. Over one year, revascularisation made no difference to the composite cognitive score (adjusted difference −0.15 SD, 95% CI −0.54 to 0.24), and the degree of perfusion delay did not change that (interaction P = 0.40).

The key analysis rests on 51 people, so modest effects cannot be ruled out. But it does not support offering carotid surgery or stenting to older adults with asymptomatic stenosis in the hope of improving memory or thinking.

• Do not recommend carotid revascularisation to improve cognition in asymptomatic stenosis.
• Continue intensive medical management of vascular risk factors in carotid stenosis.
• Investigate cognitive impairment in someone with carotid stenosis as you would in anyone else.
• Note the small subgroup; this rules out large but not modest effects.

Why it matters

Restoring flow to an under-perfused hemisphere was a plausible route to better cognition, and it did not hold up.

Don't overread it

A small subgroup of a larger trial — modest cognitive effects remain possible.

The statistics, in plain English

A difference of −0.15 SD with an interval from −0.54 to 0.24 crosses zero, so no benefit was shown. With only 51 people in the key group, the interval is wide.

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