Neuroendovascular Surgery for Acute Ischemic Stroke: All Patients All the Time.

A cute stroke is one of the leading causes of death worldwide; an estimated 85% of acute strokes are caused by cerebral ischemia, and only 30% to 40% are large-vessel occlusions amenable to intervention. An analysis of the long journey of acute stroke management shows the substantial influence of technology on the safety and efficacy of intraarterial mechanical thrombectomy. Initial randomized controlled trials (RCTs) of acute stroke treatment focused on intra-arterial infusion of thrombolytic agents (Prolyse in Acute Cerebral Thromboembolism [PROACT] II and the Middle Cerebral Artery Embolism Local Fibrinolytic Intervention Trial [MELT]). In the subsequent years, those trials were followed by mechanical thrombectomy trials, Interventional Management of Stroke (IMS) III, Synthesis Expansion: A Randomized Controlled Trial on Intra-Arterial vs Intravenous Thrombolysis in Acute Ischemic Stroke (SYNTHESIS Expansion), and Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE). These trials predominantly used a first-generation thrombectomy device, the Merci retriever (Stryker, Kalamazoo, Michigan). The IMS III trial was stopped prematurely because the results did not show any significant difference in functional outcomes after thrombectomy plus intravenous recombinant tissue-type plasminogen activator (tPA) compared with intravenous tPA alone. These mechanical thrombectomy trials had limitations, primarily that documentation of largevessel occlusion was not obligatory. In IMS III, 20% of patients randomized to the endovascular group had no large-vessel occlusion. Clearly, these patients would not benefit from endovascular therapy. Technology moved forward, and newer stent retrievers, the Solitaire (Covidien, Irvine, California) and the Trevo (Stryker), received Conformité Européenne approval in 2008 and 2009, respectively. In 2012, they were approved for use by the US Food and Drug Administration. However, retrievable stents were used in only a minority of patients in the mechanical thrombectomy trials. For example, these stents were used in only 13% of cases in SYNTHESIS Expansion. The year 2015 can be unequivocally called a watershed moment in the management of acute stroke secondary to large-vessel occlusion. Five RCTs favoring mechanical thrombectomy over medical management with intravenous tPA alone for large-vessel occlusion in the setting of anterior circulation stroke were published. These RCTs (SolitaireWith the Intention for Thrombectomy as Primary Endovascular Treatment [SWIFT PRIME], Multicenter Randomized Clinical Trial of Endovascular Treatment of Acute Ischemic Stroke in the Netherlands [MR CLEAN], Extending the Time for Thrombolysis in Emergency Neurological Deficits–Intra-Arterial [EXTEND-IA], Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times [ESCAPE], and Randomized Trial of Revascularization With Solitaire FR Device vs Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset [REVASCAT]) endorsed the superiority of endovascular treatment over medical management alone. The patients underwent thrombectomy within a time frame of 6 to 12 hours after symptom onset. In view of the substantial and conclusive evidence stemming from these 5 trials, the American Heart Association/American Stroke Association guidelines were updated. According to the 2015 guidelines update, there is a Class I (strong) recommendation (Level of Evidence A) for stent-retriever thrombectomy if all the following criteria are met: prestroke modified Rankin Scale (mRS) score of 0 to 1, acute ischemic stroke receiving intravenous recombinant tPA within 4.5 hours of onset according to guidelines from professional medical societies, causative occlusion of the internal carotid artery (ICA) or proximal middle cerebral Ashish Sonig, MD, MS, MCh*‡