Background and purpose: 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.
Methods: 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.
Results: 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).
Conclusion: 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.
Keywords: Middle cerebral artery; Relative risk; Stroke; Thrombectomy; Tissue-type plasminogen activator.