Embolectomy in Acute SYlvian Thrombosis in Refractory or Ineligible Patients to ALteplase

This trial aims at comparing two strategies currently used to address acute ischemic stroke of the middle cerebral artery : medical treatment without endovascular treatment on the one hand, and medical treatment plus endovascular treatment on the other hand. The efficiency of the strategies will be assessed in terms of early neurological clinical recovery. The study will focus on three particular situations : (1) tandem internal carotid and middle cerebral artery occlusion, (2) situations where patient cannot benefit from fibrinolysis because of high risk of haemorrhage, (3) situations where fibrinolysis is not recommended because of a delay superior to 4.5 hours. The hypothesis to be tested is that medical approach plus endovascular treatment is superior to medical treatment alone