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Background: Understanding clot composition may allow for better technical planning and improved outcomes in mechanical thrombectomy (MT). We sought to correlate clot composition with reperfusion outcomes in MT. Methods: Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin and eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of First-Pass Effect (mTICI2c/3, FPE) and the number of device passes. Results: A total of 1430 patients (mean age, 68.4±13.5years; median [IQR] baseline NIHSS,17.2 [10.5-23]; IV-tPA use, 36%; Stent-Retrievers [SR], 27%; Contact Aspiration [CA], 27%; Combined SR + CA, 43%) were included. The median [IQR] number of passes was 1 [1-2]. FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for RBC-rich (P Conclusion: Despite the lack of correlation between clot histology and FPE in the overall population, our study adds to the growing body of evidence supporting the notion that clot composition influences reperfusion treatment strategy outcomes. Additional studies are needed.

BackgroundSeveral animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.ObjectiveTo investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.MethodsAs part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).ResultsMT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.ConclusionsHistological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Endovascular treatment for dural sinus thrombosis is typically reserved for a small subset of patients who fail medical management. Conventional neurovascular aspiration catheters are suboptimal for use in dural sinus thrombosis given their relatively small caliber with respect to the large dural sinuses and risk of significant blood loss if continuous suction is applied through the catheter as it traverses patent portions of the large veins. We present a case where the Penumbra Lightning aspiration system, currently approved for thrombectomy in the peripheral and pulmonary vasculature, was successfully used for dural sinus thrombectomy with rapid clinical improvement of the patient.

Background and aim Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT. Methods Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software. Results 154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values 0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05). Conclusion Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.

BackgroundWe retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiologyMethodsConsecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ2test for categorical variables.Results1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%).ConclusionsOur study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology.

Hemorrhagic intracranial artery dissections are unstable lesions, with a high propensity for rebleeding (up to 40%) in the acute period. Imaging plays an important role in the diagnosis and management of intracranial artery dissections. In this paper, we describe 2 cases in which the dissected intracranial artery underwent rapid morphological change within 3 days or less, highlighting the importance of short-term follow-up imaging in patients with these hemorrhagic lesions.

Background and Purpose— Mechanical thrombectomy has been shown to improve clinical outcomes in patients with acute ischemic stroke. However, the impact of balloon guide catheter (BGC) use is not well established. Methods— STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever as first-line therapy. In this study, an independent core laboratory, blinded to the clinical outcomes, reviewed all procedures and angiographic data to classify procedural technique, target clot location, recanalization after each pass, and determine the number of stent retriever passes. The primary clinical end point was functional independence (modified Rankin Scale, 0–2) at 3 months as determined on-site, and the angiographic end point was first-pass effect (FPE) success rate from a single device attempt (modified Thrombolysis in Cerebral Infarction, ≥2c) as determined by a core laboratory. Achieving modified FPE (modified Thrombolysis in Cerebral Infarction, ≥2b) was also assessed. Comparisons of clinical outcomes were made between groups and adjusted for baseline and procedural characteristics. All participating centers received institutional review board approval from their respective institutions. Results— Adjunctive technique groups included BGC (n=445), distal access catheter (n=238), and conventional guide catheter (n=62). The BGC group had a higher rate of FPE following first pass (212/443 [48%]) versus conventional guide catheter (16/62 [26%]; P =0.001) and distal access catheter (83/235 [35%]; P =0.002). Similarly, the BGC group had a higher rate of modified FPE (294/443 [66%]) versus conventional guide catheter (26/62 [42%]; P P =0.003). The BGC group achieved the highest rate of functional independence (253/415 [61%]) versus conventional guide catheter (23/55 [42%]; P =0.007) and distal access catheter (113/218 [52%]; P =0.027). Final revascularization and mortality rates did not differ across the groups. Conclusions— BGC use was an independent predictor of FPE, modified FPE, and functional independence, suggesting that its routine use may improve the rates of early revascularization success and good clinical outcomes. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Since the initial reports surfaced of a novel Coronavirus causing illness and loss of life in Wuhan, China, COVID-19 has rapidly spread across the globe infecting millions and leaving hundreds of thousands dead. As hospitals cope with the influx of COVID-19 patients, new challenges have arisen as healthcare systems care for COVID-19 patients while still providing essential emergency care for patients with acute strokes and acute myocardial infarction. Adding to this complex scenario are new reports that COVID-19 patients are at increased risk of thromboembolic complications including strokes. In this paper, we detail our experience caring for acute stroke patients, and provide some insight into neurointerventional workflow modifications that have helped us adapt to the COVID-19 era., Highlights: • COVID-19 continues its relentless march through the United States and the globe, presenting unique challenges for healthcare providers as they treat other emergent conditions while minimizing the risk of COVID-19 exposure and infection. • Acute stroke is especially challenging during the COVID-19 due to time constraints required for effective mechanical thrombectomy to improve neurologic outcomes and survival in patients whose COVID infection status is unknown. • The institutional protocol for mechanical thrombectomy described in this article may help inform models at other centers as they prepare for their respective COVID peaks

Supplemental Digital Content is available in the text., Background: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation. Methods: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0–2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass. Results: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients (P

Background and Purpose— Mechanical thrombectomy with stent retrievers has become standard of care for treatment of acute ischemic stroke patients because of large vessel occlusion. The STRATIS registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) aimed to assess whether similar process timelines, technical, and functional outcomes could be achieved in a large real world cohort as in the randomized trials. Methods— STRATIS was designed to prospectively enroll patients treated in the United States with a Solitaire Revascularization Device and Mindframe Capture Low Profile Revascularization Device within 8 hours from symptom onset. The STRATIS cohort was compared with the interventional cohort of a previously published SEER patient-level meta-analysis. Results— A total of 984 patients treated at 55 sites were analyzed. The mean National Institutes of Health Stroke Scale score was 17.3. Intravenous tissue-type plasminogen activator was administered in 64.0%. The median time from onset to arrival in the enrolling hospital, door to puncture, and puncture to reperfusion were 138, 72, and 36 minutes, respectively. The Core lab–adjudicated modified Thrombolysis in Cerebral Infarction ≥2b was achieved in 87.9% of patients. At 90 days, 56.5% achieved a modified Rankin Scale score of 0 to 2, all-cause mortality was 14.4%, and 1.4% suffered a symptomatic intracranial hemorrhage. The median time from emergency medical services scene arrival to puncture was 152 minutes, and each hour delay in this interval was associated with a 5.5% absolute decline in the likelihood of achieving modified Rankin Scale score 0 to 2. Conclusions— This largest-to-date Solitaire registry documents that the results of the randomized trials can be reproduced in the community. The decrease of clinical benefit over time warrants optimization of the system of care. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Background and Purpose— Nearly 30% of large vessel occlusion acute ischemic stroke clots are from an unknown source. We assessed histological clot composition in a series of patients with large vessel occlusion and investigated correlations between clot composition and stroke pathogenesis. Methods— As part of the multi-institutional STRIP registry (Stroke Thromboembolism Registry of Imaging and Pathology), consecutive emboli retrieved during mechanical thrombectomy were stained using Martius Scarlett Blue and analyzed using machine learning software. We assessed proportions of red blood cells, fibrin, platelets, and white blood cells. Correlations between clot components and stroke pathogenesis (large artery atherosclerosis, cardioembolism, and stroke of undetermined pathogenesis) were assessed using SPSS22. Results— One hundred five patients were included. The proportion of platelet-rich clots (55.0% versus 21.2%; P =0.005) and percentage of platelet content (22.1±4.2% versus 13.9±14.2%; P =0.03) was significantly higher in the large artery atherosclerosis group compared with the cardioembolic group. The proportion of platelet-rich clots (50.0% versus 21.2%; P =0.024) was also significantly higher in the cryptogenic group compared with cardioembolic cases. Large artery atherosclerosis and cryptogenic cases had a similar proportion of platelet-rich clots (55.0% versus 50.0%; P =0.636). There was no significant difference between stroke pathogenesis and the other major clot components. Conclusions— High platelet content of emboli is associated with a large artery atherosclerosis etiology of large vessel occlusion.

BackgroundCurrent studies on clot characterization in acute ischemic stroke focus on fibrin and red blood cell composition. Few studies have examined platelet composition in acute ischemic stroke clots. We characterize clot composition using the Martius Scarlet Blue stain and assess associations between platelet density and CT density.Materials and methodHistopathological analysis of the clots collected as part of the multi-institutional STRIP registry was performed using Martius Scarlet Blue stain and the composition of the clots was quantified using Orbit Image Analysis (www.orbit.bio) machine learning software. Prior to endovascular treatment, each patient underwent non-contrast CT (NCCT) and the CT density of each clot was measured. Correlations between clot components and clinical information were assessed using the χ2 test.ResultsEighty-five patients were included in the study. The mean platelet density of the clots was 15.7% (2.5–72.5%). There was a significant correlation between platelet-rich clots and the absence of hyperdensity on NCCT, (ρ=0.321, p=0.003*, n=85). Similarly, there was a significant inverse correlation between the percentage of platelets and the mean Hounsfield Units on NCCT (ρ=−0.243, p=0.025*, n=85).ConclusionMartius Scarlet Blue stain can identify patients who have platelet-rich clots. Platelet-rich clots are isodense on NCCT.

Dementia is a chronic loss of neurocognitive function that is progressive and irreversible. Although rare, dural arteriovenous fistulas (DAVFs) could present with a rapid decline in neurocognitive function with or without Parkinson-like symptoms. DAVFs represent a potentially treatable and reversible cause of dementia. Here, we report the case of an elderly woman diagnosed with a DAVF after presenting with new-onset seizures, deteriorating neurocognitive function, and Parkinson-like symptoms.

We report the first utilization of intraoperative central venous pressure (CVP) monitoring in the resection of an orbital arteriovenous malformation. A 24-year-old woman with a history of a left orbital mass who had previously undergone resection of a cranio-orbital arteriovenous malformation presented with gradual recurrence in the left orbit. She visited the emergency department with sudden vision loss, which resolved over several hours. This transient vision loss was thought to be due to a steal phenomenon from the ophthalmic artery due to the residual vascular malformation. Further surgical resection was undertaken. A preoperative angiogram identified residual feeding vessels, and the larger vessels were embolized. At the start of the procedure, her CVP was elevated (29 mm Hg), as measured by a central venous line. The remaining feeding vessels were surgically ligated, and an intraoperative arteriogram confirmed their successful ablation. At the conclusion of the procedure, the CVP had decreased to 9 mm Hg.

Multiple recent randomized controlled trials have proven the benefit of mechanical thrombectomy using stent retrievers for emergent large vessel occlusion (ELVO). 1–5 Techniques currently used for endovascular treatment of stroke employ either direct aspiration, stent retriever thrombectomy or a combination of both. When stent retrievers are used, temporary flow arrest with an extracranial balloon guide catheter or assisted local aspiration with a large bore intracranial suction catheter is recommended. This allows for more complete recanalization and prevents embolization to previously uninvolved territories. Recent advancements in large bore intracranial suction catheter technology have made it easier to utilize coaxial stent retriever thrombectomy assisted by local aspiration. At our high-volume comprehensive stroke center, we have found the second generation large bore intracranial Arc support catheter (ev3 Neurovascular, Irvine, CA) to be extremely effective when used in combination with the Solitaire stent retriever (ev3 Neurovascular, Irvine, CA). We have found the Arc support catheter to be much more navigable, less prone to kinking and easier to deliver into the M1 segment (without causing spasm) than the first generation local aspiration catheters. Additionally, the Arc support catheter is less costly than the currently available suction catheters. The Sol-Arc technique begins with placement of a stent retriever device across the embolic occlusion by deployment though a 021 or 027 microcatheter. This microcatheter is placed coaxially through the Arc support catheter which is positioned just proximal to the embolus. After waiting 5 minutes, the stent retriever is pulled inside the Arc support catheter which is simultaneously aspirated. Subsequently, the Arc support catheter is removed while aspirating the guiding sheath in the neck. This technique should allow for faster, safer and more successful stent retriever thrombectomy when used in conjunction with local aspiration. Disclosures A. Onofrio: None. A. Miller: None. J. Hise: None. I. Thacker: None. J. Haithcock: None. D. Graybeal: None. K. Layton: None.

We studied 100 patients in whom symptomatic pseudarthrosis had been established at more than 9 months after lumbar spine fusion. All patients were treated with a pulsed electromagnetic field device worn consistently 2 hours a day for at least 90 days. Solid fusion was achieved in 67% of patients. Effectiveness was not statistically significantly different for patients with risk factors such as smoking, use of allograft, absence of fixation, or multilevel fusions. Treatment was equally effective for posterolateral fusions (66%) as with interbody fusions (69%). For patients with symptomatic pseudarthrosis after lumbar spine fusion, pulsed electromagnetic field stimulation is an effective nonoperative salvage approach to achieving fusion.