Techniques for endovascular treatment of acute ischemic stroke: from intra-arterial fibrinolytics to stent-retrievers.

Abstract

Early recanalization of occluded vessels in acute ischemic stroke (AIS) either by intravenous thrombolysis or endovascular revascularization has been shown to be associated with improved clinical outcome and reduced mortality.1 Initial works on endovascular treatment (EVT) of AIS was published in the 1980s.2,3 Since then, the endovascular techniques for AIS treatment have tremendously improved, advancing from intra-arterial administration of thrombolytic drugs to first-generation mechanical thrombectomy devices (Merci clot retriever and Penumbra clot aspiration) and more recently to second-generation mechanical thrombectomy devices (stent-retrievers; Figure 1). Introduction of various tools and techniques in EVT for AIS will, for obvious reasons, affect the efficacy and safety. Figure 1. Evolution of endovascular techniques for acute ischemic stroke and clinical trials. IMS indicates Interventional Management of Stroke; MERCI, Mechanical Embolus Removal in Cerebral Ischemia; MR CLEAN, Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; PROACT, Prolyse in Acute Cerebral Thromboembolism; SWIFT, Solitaire With the Intention for Thrombectomy; and TREVO, Thrombectomy Revascularization of Large Vessel Occlusions in Acute Ischemic Stroke. On the other hand, intravenous thrombolysis was evaluated in several large randomized trials and was shown to improve clinical outcome at 90 days if treatment was initiated within 3 hours of stroke onset.4 Subsequently, the European Cooperative Acute Stroke Study (ECASS) III showed the benefit of intravenous thrombolysis between 3 and 4.5 hours.5 After establishing the efficacy of intravenous recombinant tissue-type plasminogen activator (r-tPA) in the treatment of AIS, EVT had to be evaluated against intravenous treatment. A long time elapsed before the results of the first randomized controlled trials were published in 2013 demonstrating no major difference between intravenous r-tPA treatment and EVT for AIS.6–8 Noteworthy, these trials had several limitations including the fact that all EVT were approved for use.9 …