Stenting and surgery have similar effects on stroke in patients with severe carotid artery stenosis

Carotid artery surgery and stenting have comparable long-term effects on fatal or disabling strokes in asymptomatic patients with severe carotid artery stenosis. This is the conclusion of a last minute research presented in a Hot Line session today at the ESC 2021 Congress and published simultaneously in The Lancet.

Patients with severe carotid artery stenosis are at high risk for stroke and carotid artery stenting (CAR) and carotid artery surgery, also called carotid endarterectomy (EA), can restore patency and reduce the long-term risk of stroke. Data from the German National Registry have shown that in asymptomatic patients, CAS and CEA are both associated with an approximately 1% risk of disabling stroke or death. Comparative data is lacking on the long-term protective effects of the two procedures.

ACST-2 was the largest trial comparing the long-term effect of CS versus ACE on stroke in asymptomatic patients with severely narrowed carotid artery that had not yet caused a stroke. The trial included patients with severe carotid artery narrowing (60% or more reduction in diameter on ultrasound) found by chance, but without recent stroke or other neurological symptoms. According to their doctor, the participants needed a SAC or an ACE, but the doctor and the patient had no idea which procedure was better.

A total of 3,625 patients were recruited from 130 centers in 33 countries. Participants were randomized 1: 1 in the CAS or CEA and followed for an average of five years. The main outcome measures were: 1) the risks associated with the intervention (morbidity and mortality in the month following the intervention); and, most importantly, 2) non-procedural stroke, subdivided by severity.

Regarding procedural risks, 1% of patients in both groups had an invalidating stroke or died within 30 days (15 attributed to CAS and 18 to CEA) and 2% had a non-invalidating procedural stroke (48 attributed to CAS and 29 at CEA).

The primary endpoint was a five-year non-procedural stroke; fatal or disabling stroke occurred in 2.5% of patients in each group, for a rate ratio (RR) of CAS to CEA of 0.98 (95% confidence interval [CI] 0.64-1.48; p = 0.91), and any non-procedural stroke occurred in 5.3% of the CAS group versus 4.5% of the CEA group (RR 1.16; 95% CI 0.86 to 1.57; p = 0.33). A meta-analysis of this trial and all other major CAS versus CEA trials yielded a similar non-significant result for any stroke (RR 1.11; 95% CI 0.91 to 1.32; p = 0, 21).

We have shown that for patients with severely narrowed carotid artery, stenting and surgery have similar effects on the odds of having a crippling or fatal stroke. The risk of each procedure is approximately 1%. After that, however, the annual risk over the next five or more years is halved, from 1% to 0.5% per year. “

Principal Investigator, Professor Alison Halliday, University of Oxford, UK