Comparative outcomes of self-expanding stenting in symptomatic MCA-M2 versus MCA-M1 segment stenosis.

Background: The outcomes of self-expanding stenting for symptomatic middle cerebral artery (MCA) M2 segment stenosis remain unclear. We aimed to analyze whether the safety and efficacy of M2 and M1 segment stenting procedures differ.

Methods: This multicenter retrospective cohort study analyzed data from three stroke centers involving patients who underwent self-expanding stent placement for symptomatic M1 or M2 stenosis between January 2017 and August 2024. Patients were stratified into two groups: M1 stenting (M1S) and M2 stenting (M2S). Safety outcomes included 30-day peri-procedural complications, while efficacy outcomes comprised ipsilateral stroke beyond 30 days through 6 months and in-stent restenosis (ISR) at 6 months. Propensity score matching (PSM) was used to balance baseline characteristics between groups.

Results: A total of 318 patients were enrolled. Compared with the M1S group, the M2S group had a similar incidence of 30-day periprocedural complications (5.0% vs 5.4%; odds ratio (OR) 1.08, 95% confidence interval (CI) 0.24 to 4.93; P=0.917), incidence of ipsilateral stroke between 30 days and 6 months postprocedure (3.1% vs 3.9%; OR 1.27, 95% CI 0.16 to 10.40; P=0.821) and ISR rate (25.0% vs 15.8%; OR 0.56, 95% CI 0.23 to 1.35; P=0.193). After a 2:1 PSM (78 vs 39 patients), the two groups remained comparable in terms of 30-day complications, the incidence of ipsilateral stroke beyond 30 days through 6 months, and the ISR rate.

Conclusion: Self-expanding stenting for symptomatic M2 stenosis is technically feasible, with a safety and efficacy profile comparable to those of M1 interventions. These preliminary findings warrant validation in randomized trials.