Efficacy and safety of mechanical thrombectomy for M2 segment of middle cerebral artery: a systematic review and meta-analysis.

Abstract

The efficacy and safety of mechanical thrombectomy (MT) for M2 segment occlusion of middle cerebral artery in patients with acute ischemic stroke (AIS) was investigated. We searched PubMed and EMBASE from inception to 16 April 2019 for relevant studies, calculated the pool relative risks (RRs) of 3-month functional independence (modified Rankin scale score 0-2), death and symptomatic intracerebral hemorrhage (sICH) in MT for M2 segment occlusion in patients with AIS versus those of M1 segment or best medical care. Nine studies enrolling 2152 patients compared MT for patients with AIS of M2 segment occlusion and those of M1 segment occlusion. MT for M2 occlusion had a higher rate of 3-month functional independence compared to the patients with M1 occlusion. (RR 1.27, 95% CI 1.11-1.44, P < 0.001) and decreased death (RR 0.74; 95% CI 0.58-0.96, P = 0.022) with similar risk of sICH (RR 1.11; 95% CI 0.65-1.87, P = 0.707). Four studies enrolling 1016 patients compared MT and best medical care for patients with AIS of M2 occlusion. MT for M2 occlusion benefit more than best medical care on 3-month functional independence (RR 1.43, 95% CI 1.08-1.90, P = 0.011) and death (RR 0.46; 95% CI 0.22-0.96, P = 0.022) with similar risk of sICH (RR 1.65; 95% CI 0.66-4.13; P = 0.286). MT for M2 segment benefit patients with AIS on 3-month functional independence compared with that of M1 segment or medical care, without increasing the risk of sICH.