[Mechanical thrombectomy in acute ischemic stroke. What is the position after the latest study results?].

Mechanical devices for the recanalization of vessel occlusions in severe acute ischemic stroke have been developed for more than a decade. Several devices have been approved for clinical use on the basis of uncontrolled case series. Many neurologists have asked for randomized clinical trials comparing the new devices with standard treatment, e.g. thrombolytic therapy within a 4.5 h time window. The first 3 investigator initiated randomized trials published in 2013 failed to show superiority of mechanical thrombectomy over standard treatment. In the aftermath of these negative results several new trials with changes in design (e.g. shorter time window and only proximal vessel occlusions) and the use of modern devices with proven higher recanalization rates, so called stent retrievers, have been launched. In October 2014 the first of these new trials was presented and showed a clear superiority of thrombectomy. Based on this result interim analyses of five other studies were performed and most were prematurely terminated because of overwhelming efficacy. Only one trial testing another type of recanalization device failed to reach a statistically significant result. Currently five studies have already been published and two more studies have been presented at scientific conferences. This article provides an overview of the study protocols and the results of the individual studies, their common features and the characteristics of patients who benefit from this treatment. Finally, the consequences that these results may have for the treatment of patients with severe stroke caused by proximal vessel occlusion are discussed.