Intracranial strokes: Mechanical thrombectomy using the merci and penumbra devices

The use of catheter-directed, endovascular mechanical thrombolysis has revolutionized the treatment of acute ischemic strokes in the last few years. Acute ischemic stroke remains the third most common cause of death and the first most common cause of permanent adult disability in industrialized nations. Each year, approximately 795,000 people experience a new or recurrent stroke in the USA, with its direct and indirect annual cost estimated as more than $40 billion. The only Food and Drug Administration (FDA)-approved medical therapy for acute ischemic stroke is the intravenous (IV) administration of recombinant tissue-type plasminogen activator (rtPA) within 3 h of symptom onset. The European Cooperative Acute Stroke Study (ECASS) III trial expanded the utilization of IV rtPA up to 4.5 h from symptom onset, albeit with more contraindications. Given this restricted therapeutic window, less than 1 % of acute ischemic stroke patients receive IV rtPA. Moreover, the recanalization rates of IV rtPA for proximal, large vessel occlusions range from only 10 % for internal carotid artery (ICA) occlusions to 30 % for middle cerebral artery (MCA) occlusions.