Novel and emerging technologies for endovascular thrombectomy
E ndovascular thrombectomy is now the standard of care for eligible patients with acute ischemic stroke secondary to large vessel occlusion (LVO). 40 Endovascular thrombectomy owes much of its success to the development of newer-generation devices, including stent retrievers and specialized aspiration catheters. 4,28,34 It has equally benefitted from the establishment of hospital stroke networks and transfer protocols that have reduced the time from symptom onset to reperfusion. 2,3,29,33,45
... on. 2,3,29,33,45 Improved diagnostic imaging techniques have also helped to more accurately identify eligible patients who might benefit from the procedure. 4, 7, 28, 34 Together, these efforts delivered improved functional outcomes in 5 seminal randomized trials. 5, 7, 9, 19, 24, 43, 48, 54 Despite these groundbreaking advances in endovascular stroke therapy, successful revascularization, as defined by Thrombolysis in Cerebral Infarction (TICI) Grade 2b/3, is not always feasible and procedural complications are not uncommon. 1, 6, 15, 38, 53 In addition to endovascular thrombectomy technique modifications, several device improvements and novel technologies have recently been introduced to improve revascularization success while reducing complication rates. Note that because these devices are new, supporting evidence for some of the claims that these devices advertise is the focus of ongoing research and is not yet available in the literature. Stent Retriever Devices Stent retriever thrombectomy devices work primarily by self-expanding into the surrounding vessel occlusion and integrating the thrombotic material into the stent's struts. Commonly used stent retrievers that are currently available include the Trevo ProVue (Stryker Neurovascular) and the Solitaire FR (Medtronic Neurovascular). They are deployed across an occluding thrombus by unsheathing an overlying microcatheter. As the stent retriever unfolds to engage the thrombus, it applies a radial force that compresses the thrombus against the vessel wall and immediately restores partial reperfusion of the distal vasculature. After allowing 2-5 minutes for the stent struts to adequately engage the thrombus, careful retraction of the stent and microcatheter as a single unit, under balloon guide catheter (BGC) occlusion or distal aspiration, removes the clot. The rate of TICI Grade 2b/3 achieved with the current stent retriever technology ranges from 59% to 86%, and 90-day modified Rankin Scale (mRS) scores of 0-2 ABBREVIATIONS ADAPT = A Direct Aspiration First Pass Technique; BGC = balloon guide catheter; ERIC = Embolus Retriever with Interlinked Cages; ICH = intracerebral hemorrhage; ID = inner diameter; LVO = large vessel occlusion; mRS = modified Rankin Scale; OD = outer diameter; TICI = Thrombolysis in Cerebral Infarction.