Endovascular Mechanical Thrombectomy for Acute Ischemic Stroke: A New Standard of Care

Ding, Dale

Abstract

The treatment of acute ischemic stroke (AIS) in the setting of intracranial large artery occlusion (LAO) with intravenous tissue plasminogen activator (IV-tPA) is associated with low rates of recanalization and high rates of neurological morbidity and functional dependence. Endovascular intervention, particularly mechanical thrombectomy, is a promising therapeutic adjunct to IV-tPA for the treatment of acute LAO. However, until recently, its efficacy has been controversial. In this brief review, we analyze the criticisms of three negative randomized controlled trials (RCT) of endovascular stroke treatment and evaluate the results from seven positive endovascular stroke RCTs that have recently been presented or published. IMS III, MR RESCUE, and SYTHESIS Expansion were three RCTs that failed to show a benefit from endovascular stroke therapy. Major criticisms of these studies included a lack of routine screening for LAO, resulting in the selection of AIS patients without LAO for endovascular intervention, and a low utilization rate of modern endovascular thrombectomy devices, leading to substandard rates of successful recanalization. MR CLEAN was the first phase III RCT to show a significant clinical benefit from endovascular stroke therapy. The dissemination of its findings elicited a cascade of positive results from, to date, six additional endovascular stroke RCTs, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, THERAPY, and THRACE, which were halted prematurely for efficacy. The cumulative evidence from these studies shows an overwhelming benefit from the endovascular treatment of acute LAO, therefore effectively establishing a new standard of care for the management of AIS.