Study started April 2023, Ongoing ClinicalTrials.gov Identifier: NCT05899582 ClinicalTrials.gov: https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S000D9N3&selectaction=Edit&uid=U00053OC&ts=5&cx=-8ug04h The CMOSS-2 trial is a government-funded, prospective, multicenter, randomized controlled trial. It will recruit symptomatic chronic occlusion of the middle cerebral artery in patients with severe hemodynamic insufficiency. Only high-volume center with a proven track record will be included. Patients will be randomized (1:1) to best medical treatment alone or medical treatment plus bypass surgery. Primary outcome is ischemic stroke in the territory of the target artery within 24 months after randomization. The CMOSS-2 trial will be conducted in 13 sites in China. Keywords: Middle cerebral artery occlusion, stroke，TIA Relevant article: ●Ma Y, Wang T, et al. CMOSS Investigators. Extracranial-Intracranial Bypass and Risk of Stroke and Death in Patients With Symptomatic Artery Occlusion: The CMOSS Randomized Clinical Trial. JAMA. 2023 Aug 22;330(8):704-714. doi: 10.1001/jama.2023.13390. PMID: 37606672; PMCID: PMC10445185.

●Gao P, Wang T, et aal. CASSISS Trial Investigators. Effect of Stenting Plus Medical Therapy vs Medical Therapy Alone on Risk of Stroke and Death in Patients With Symptomatic Intracranial Stenosis: The CASSISS Randomized Clinical Trial. JAMA. 2022 Aug 9;328(6):534-542. doi: 10.1001/jama.2022.12000IF: 120.7 Q1 . PMID: 35943472; PMCID: PMC9364128.

●Powers WJ, Clarke WR, et al. COSS Investigators. Extracranial-intracranial bypass surgery for stroke prevention in hemodynamic cerebral ischemia: the Carotid Occlusion Surgery Study randomized trial. JAMA. 2011 Nov 9;306(18):1983-92. doi: 10.1001/jama.2011.1610. Erratum in: JAMA. 2011 Dec 28;306(24):2672. Obviagele, Bruce [corrected to Ovbiagele, Bruce]. PMID: 22068990; PMCID: PMC3601825.