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BackgroundThere is a discrepancy in clinical outcomes and the achieved recanalization rates with stent retrievers in the endovascular treatment of ischemic stroke. It is our hypothesis that procedural release of embolic particulate may be one contributor to poor outcomes and is a modifiable risk. The goal of this study is to assess various treatment strategies that reduce the risk of distal emboli.MethodsMechanical thrombectomy was simulated in a vascular phantom with collateral circulation. Hard fragment-prone clots (HFC) and soft elastic clots (SECs) were used to generate middle cerebral artery (MCA) occlusions that were retrieved by the Solitaire FR devices through (1) an 8 Fr balloon guide catheter (BGC), (2) a 5 Fr distal access catheter at the proximal aspect of the clot in the MCA (Solumbra), or (3) a 6 Fr guide catheter with the tip at the cervical internal carotid artery (guide catheter, GC). Results from mechanical thrombectomy were compared with those from direct aspiration using the Penumbra 5MAX catheter. The primary endpoint was the size distribution of emboli to the distribution of the middle and anterior cerebral arteries.ResultsSolumbra was the most efficient method for reducing HFC fragments (p<0.05) while BGC was the best method for preventing SEC fragmentation (p<0.05). The risk of forming HFC distal emboli (>1000 µm) was significantly increased using GC. A non-statistically significant benefit of direct aspiration was observed in several subgroups of emboli with size 50–1000 µm. However, compared with the stent-retriever mechanical thrombectomy techniques, direct aspiration significantly increased the risk of SEC fragmentation (<50 µm) by at least twofold.ConclusionsThe risk of distal embolization is affected by the catheterization technique and clot mechanics.

BACKGROUND AND PURPOSE:Incomplete occlusion and recanalization of large and wide-neck brain aneurysms treated by endovascular therapy remains a challenge. We present preliminary clinical and angiographic results of an experimentally optimized Surpass flow diverter for treatment of intracranial aneurysms in a prospective, multicenter, nonrandomized, single-arm study.

Background and Purpose-The purpose of this study was to investigate the periprocedural morbidity, mortality, and long-term clinical and angiographic follow-up using stent-assisted coiling and stenting alone for treatment of cranial fusiform dissecting and atherosclerotic aneurysms. Methods-The Institutional Review Board approved the study. A retrospective analysis was performed of 30 fusiform dissecting and atherosclerotic aneurysms treated in 28 patients (20 females; mean age, 52.6 years). Eleven aneurysms (37%) were located in the posterior circulation. Twenty-one (70%) originated from arterial dissection and 4 aneurysms (13%) presented with subarachnoid bleeding. Twenty-four (80%) aneurysms were treated with stents and coils, whereas 6 (20%) were treated with stents alone. Results-Immediate postprocedural angiograms in 24 aneurysms treated with stent-assisted coiling showed complete occlusion in 12 and subtotal occlusion in 11 aneurysms, whereas no occlusion was seen in one aneurysm and in all 6 aneurysms treated with stents alone. A clinical improvement or stable outcome was achieved in 25 patients (89%). The 2 cases of permanent morbidity included a patient with a finger dysesthesia associated with a perforator stroke and another patient with hemiparesis and aphasia due to a delayed in-stent thrombosis. One patient died after treatment of a giant vertebrobasilar junction aneurysm. Angiographic follow-up was available in 23 of the 27 surviving patients (85%) at a mean of 16.2 months (range, 1 to 108 months). Recanalization in 4 patients (17%) at 3, 5, 24, and 36 months required retreatment in 3. In-stent stenosis of Յ50% was found in 3 patients. Conclusion-Stent-assisted coil embolization is an attractive option for ruptured and nonruptured fusiform aneurysms with stable long-term outcome. However, recanalization observed up to 3 years after the initial obliteration emphasizes the need for long-term follow-up angiography. (Stroke. 2008;39:3288-3296.)

Limited data exist on clot composition and detailed characteristics of arterial thrombi associated with large vessel occlusion in acute ischemic stroke. Advances in endovascular thrombectomy and related imaging modalities have created a unique opportunity to analyze thrombi removed from cerebral arteries. Insights into thrombus composition, etiology, physical properties and neurovascular interactions may lead to future advancements in acute ischemic stroke treatment and improved clinical outcomes. Advances in imaging techniques may enhance clot characterization and inform therapeutic decision-making prior to treatment and reveal stroke etiology to guide secondary prevention. Current imaging techniques can provide some information about thrombi, but there remains much to evaluate about relationships that may exist among thrombus composition, occlusion characteristics and treatment outcomes. Improved pathophysiological characterization of clot types, their properties and how these properties change over time, together with clinical correlates from ongoing studies, may facilitate revascularization with thrombolysis and thrombectomy. Interdisciplinary approaches covering clinical, engineering and scientific aspects of thrombus research will be key to advancing the understanding of thrombi and improving acute ischemic stroke therapy. This consensus statement integrates recent research on clots and thrombi retrieved from cerebral arteries and provides a rationale for further analyses, including current opportunities and limitations.