Mechanical Thrombectomy for Acute Ischemic Stroke

The therapy of acute ischemic stroke aims at fast recanalization of the occluded brain vessel. In contrast to intravenous thrombolysis (IVT), endovascular approaches yield higher recanalization rates especially in large vessel occlusions. Mechanical thrombectomy with the Merci Retriever received FDA approval in 2004 as an adjunct to IVT or in the case of failed recanalization after IVT. The time window for treatment is 8 h from stroke onset. However, the recanalization rate was 55%, still leaving space for further improvement. In addition to the Merci Retriever, the Penumbra System received FDA approval in 2008. The newest endovascular approach comprising retrievable intracranial stents results in an increased recanalization rate exceeding 90% and has markedly reduced the time to recanalization. On the other hand, the complication rate has not increased yet. These promising results suggest a combined therapy for acute ischemic stroke. In a first step IVT can be started independently of the size of the treating hospital and in a next step the patient is transferred to a neuroradiological center. If vessel occlusion persists, additional endovascular recanalization is performed (bridging concept). Patients who don't qualify for IVT are candidates for mechanical thrombectomy up to 8 h after stroke onset.