50 Shades of 'Groundhog Day'

The 2017 European Society for Vascular Surgery (ESVS) guidelines on carotid and vertebral artery disease concluded that the evidence did not support a role for carotid endarterectomy (CEA) or carotid artery stenting (CAS) in patients with asymptomatic carotid stenosis (ACS) in preventing cognitive impairment or dementia. What new data have emerged since 2017, and have they influenced the 2023 ESVS guidelines?

In a systematic review, 33/35 studies (94%) reported a "significant association" between ACS and cognitive impairment; 20 studies had 1-3 tests with significant cognitive impairment; 10 reported 4-6 tests with cognitive impairment; and three studies reported ≥7 tests with significant cognitive impairment. Baseline data from 1 000 patients with ACS in the second Carotid Revascularisation Endarterectomy versus Stenting Trial (CREST-2) reported that the overall Z score for cognition in patients with ACS was significantly lower than expected, especially for word list recall and word list learning. Another systematic review reported that (in the long term) 69% of patients with ACS undergoing CEA/CAS had no change in cognitive function. However, in another 25%, cognitive scores/domains were mostly unchanged, but 1-2 individual tests were significantly improved. In addition, 1 601 UK and Swedish patients with ACS were randomised in the first Asymptomatic Carotid Surgery Trial (ACST-1) to CEA or best medical therapy (BMT). There was no difference in 10 year rates of dementia (CEA 6.7% vs. 6.6% with BMT) or at 20 years (14.3% [CEA] vs. 15.5% [BMT]), suggesting that CEA did not prevent dementia vs. BMT (hazard ratio 0.98, 95% confidence interval 0.75-1.28; p = .89).

ACS is associated with significant cognitive impairment, but whether this supports a direct aetiological role, or a marker for something else, remains unknown. There is no evidence that CEA/CAS prevents late dementia. The 2023 ESVS guidelines have not changed its recommendation compared with the 2017 version.