Researchers continue to advance the science to determine best treatments for stroke. Based on an international study of 530 patients, researchers discovered that while the clot retrieval procedure endovascular thrombectomy (EVT) can dramatically improve patient outcomes after an acute ischemic stroke caused by a blockage in a large blood vessel, it did not improve outcomes in patients with blockages in medium-sized vessels. Lead investigators say study findings will help physicians quickly determine the best care for each individual case.