Cervical Dissection in Patients With Tandem Lesions Is Associated With Distal Embolism and Lower Recanalization Success.

BACKGROUND: Tandem lesions consist of cervical internal carotid artery (ICA) stenosis or occlusion, most commonly of atherosclerosis or dissection etiology, plus a large vessel occlusion. In this study, we compare outcomes in patients with atherosclerosis versus dissection of the cervical ICA. METHODS: This multicenter retrospective cohort study includes data from tandem lesion patients who underwent endovascular treatment from 2015 to 2020. Atherosclerosis was defined as ICA stenosis/occlusion associated with a calcified lesion and dissection by the presence of a tapered or flame-shaped lesion and intramural hematoma. Primary outcome: 90-day functional independence (modified Rankin Scale score, 0-2); secondary outcomes: 90-day favorable shift in the modified Rankin Scale score, modified Thrombolysis in Cerebral Infarction score 2b-3, modified Thrombolysis in Cerebral Infarction score 2c-3, symptomatic intracranial hemorrhage, parenchymal hematoma type 2, petechial hemorrhage, distal embolization, early neurological improvement, and mortality. Analysis was performed with matching by inverse probability of treatment weighting. RESULTS: We included 526 patients (68 [59-76] years; 31% females); 11.2% presented dissection and 88.8%, atherosclerosis. Patients with dissection were younger, had lower rates of hypertension, hyperlipidemia, diabetes, and smoking history. They also exhibited higher rates of ICA occlusion, multiple stents (>1), and lower rates of carotid self-expanding stents. After matching and adjusting for covariates, there were no differences in 90-day functional independence. The rate of successful recanalization was significantly lower in the dissection group (adjusted odds ratio, 0.38 [95% CI, 0.16-0.91]; P=0.031), which also had significantly higher rates of distal emboli (adjusted odds ratio, 2.53 [95% CI, 1.15-5.55]; P=0.021). There were no differences in other outcomes. Acute ICA stenting seemed to increase the effect of atherosclerosis in successful recanalization. CONCLUSIONS: This study reveals that among patients with acute stroke with tandem lesions, cervical ICA dissection is associated with higher rates of distal embolism and lower rates of successful recanalization than atherosclerotic lesions. Using techniques to minimize the risk of distal embolism may mitigate this contrast. Further prospective randomized trials are warranted to fully understand these associations.

Nationally Certified Stroke Centers Outperform Self-Attested Stroke Centers in the Florida Stroke Registry.

BACKGROUND: The Florida Stroke Act, signed into law in 2004, set criteria for Comprehensive Stroke Centers (CSC). For a set time period, Florida hospitals were permitted to either receive national certification (NC) or could self-attest (SA) as fulfilling CSC criteria. The aim of this project was to evaluate the quality of ischemic stroke care in NC versus SA stroke centers in Florida, using well-known, guideline-driven ischemic stroke outcome metrics. METHODS: A total of 37 CSCs (74% of Florida CSCs) in the Florida Stroke Registry from January 2013 through December 2018 were analyzed, including 19 SA CSCs and 18 NC (13 CSCs and 5 Thrombectomy-Capable Stroke Center). Hospital- and patient-level characteristics and stroke metrics were evaluated, adjusting for demographics, medical comorbidities, and stroke severity. RESULTS: A total of 78 424 acute ischemic stroke cases, 36 089 from SA CSCs and 42 335 from NC CSC/Thrombectomy-Capable Stroke Centers were analyzed. NC centers had older patients (73 [61-83] versus 71 [60-81]; P<0.001) with more severe strokes (median National Institutes of Health Stroke Scale score of 5 versus 4; P<0.001). NC had higher intravenous tissue-type plasminogen activator utilization (15% versus 13%; P<0.001), endovascular treatment (10% versus 7%; P<0.001) and faster median door-to-computed tomography (23 minutes [11-73] versus 31 [12-78]; P<0.001), door-to-needle (37 minutes [26-50] versus 45 [34-58]; P<0.001) and door-to-puncture times (77 minutes [50-113] versus 93 [62-140]; P<0.001). In adjusted analysis, patients arriving to NC hospitals by 3 hours were more likely to get intravenous tissue-type plasminogen activator in the 3- to 4.5-hour window (adjusted odds ratio, 1.87 [95% CI, 1.30-2.68]; P=0.001) and more likely to be treated with intravenous tissue-type plasminogen activator within 45 minutes (adjusted odds ratio, 1.61 [95% CI, 1.04-2.50]; P=0.04) compared with SA CSCs. CONCLUSIONS: Among Florida-Stroke Registry CSCs, acute ischemic stroke performance and treatment measures at NC centers are superior to SA CSCs. These findings have implications for stroke systems of care in Florida and support legislation updates requiring NC and removal of SA claims.

Safety Outcomes of Mechanical Thrombectomy Versus Combined Thrombectomy and Intravenous Thrombolysis in Tandem Lesions.

BACKGROUND: We aimed to describe the safety and efficacy of mechanical thrombectomy (MT) with or without intravenous thrombolysis (IVT) for patients with tandem lesions and whether using intraprocedural antiplatelet therapy influences MT's safety with IVT treatment. METHODS: This is a subanalysis of a pooled, multicenter cohort of patients with acute anterior circulation tandem lesions treated with MT from 16 stroke centers between January 2015 and December 2020. Primary outcomes included symptomatic intracranial hemorrhage (sICH) and parenchymal hematoma type 2. Additional outcomes included hemorrhagic transformation, successful reperfusion (modified Thrombolysis in Cerebral Infarction score 2b-3), complete reperfusion (modified Thrombolysis in Cerebral Infarction score 3), favorable functional outcome (90-day modified Rankin Scale score 0-2), excellent functional outcome (90-day modified Rankin Scale score 0-1), in-hospital mortality, and 90-day mortality. RESULTS: Of 691 patients, 512 were included (218 underwent IVT+MT and 294 MT alone). There was no difference in the risk of sICH (adjusted odds ratio [aOR], 1.22 [95% CI, 0.60-2.51]; P=0.583), parenchymal hematoma type 2 (aOR, 0.99 [95% CI, 0.47-2.08]; P=0.985), and hemorrhagic transformation (aOR, 0.95 [95% CI, 0.62-1.46]; P=0.817) between the IVT+MT and MT alone groups after adjusting for confounders. Administration of IVT was associated with an increased risk of sICH in patients who received intravenous antiplatelet therapy (aOR, 3.04 [95% CI, 0.99-9.37]; P=0.05). The IVT+MT group had higher odds of a 90-day modified Rankin Scale score 0 to 2 (aOR, 1.72 [95% CI, 1.01-2.91]; P=0.04). The odds of successful reperfusion, complete reperfusion, 90-day modified Rankin Scale score 0 to 1, in-hospital mortality, or 90-day mortality did not differ between the IVT+MT versus MT alone groups. CONCLUSIONS: Our study showed that the combination of IVT with MT for tandem lesions did not increase the overall risk of sICH, parenchymal hematoma type 2, or overall hemorrhagic transformation independently of the cervical revascularization technique used. However, intraprocedural intravenous antiplatelet therapy during acute stent implantation might be associated with an increased risk of sICH in patients who received IVT before MT. Importantly, IVT+MT treatment was associated with a higher rate of favorable functional outcomes at 90 days.

Portable stroke detection devices: a systematic scoping review of prehospital applications.

BACKGROUND: The worldwide burden of stroke remains high, with increasing time-to-treatment correlated with worse outcomes. Yet stroke subtype determination, most importantly between stroke/non-stroke and ischemic/hemorrhagic stroke, is not confirmed until hospital CT diagnosis, resulting in suboptimal prehospital triage and delayed treatment. In this study, we survey portable, non-invasive diagnostic technologies that could streamline triage by making this initial determination of stroke type, thereby reducing time-to-treatment. METHODS: Following PRISMA guidelines, we performed a scoping review of portable stroke diagnostic devices. The search was executed in PubMed and Scopus, and all studies testing technology for the detection of stroke or intracranial hemorrhage were eligible for inclusion. Extracted data included type of technology, location, feasibility, time to results, and diagnostic accuracy. RESULTS: After a screening of 296 studies, 16 papers were selected for inclusion. Studied devices utilized various types of diagnostic technology, including near-infrared spectroscopy (6), ultrasound (4), electroencephalography (4), microwave technology (1), and volumetric impedance spectroscopy (1). Three devices were tested prior to hospital arrival, 6 were tested in the emergency department, and 7 were tested in unspecified hospital settings. Median measurement time was 3 minutes (IQR: 3 minutes to 5.6 minutes). Several technologies showed high diagnostic accuracy in severe stroke and intracranial hematoma detection. CONCLUSION: Numerous emerging portable technologies have been reported to detect and stratify stroke to potentially improve prehospital triage. However, the majority of these current technologies are still in development and utilize a variety of accuracy metrics, making inter-technology comparisons difficult. Standardizing evaluation of diagnostic accuracy may be helpful in further optimizing portable stroke detection technology for clinical use.

Exposure to Neurointervention During Neurology Training.

There is an urgent need to include a dedicated neurointerventional rotation in the curriculum of neurology residency and vascular neurology fellowship based on the paradigm shift in recent years of stroke workflow. The recent changes coupled with growing body of evidence about lack of neurointerventional exposure in current curriculum makes it imperative for us to restructure the training for future neurologists. The exposure will prepare the neurology house-staff for the contemporary management of cerebrovascular diseases and will lead to high quality, patient-centric care.

Factors Associated With Decreased Accuracy of Modified Thrombolysis in Cerebral Infarct Scoring Among Neurointerventionalists During Thrombectomy.

Background and Purpose: The modified Thrombolysis in Cerebral Infarct (mTICI) score is used to grade angiographic outcome after endovascular thrombectomy. We sought to identify factors that decrease the accuracy of intraprocedural mTICI. Methods: We performed a 2-center retrospective cohort study comparing operator (n=6) mTICI scores to consensus scores from blinded adjudicators. Groups were also assessed by dichotomizing mTICI scores to 0­2a versus 2b­3. Results: One hundred thirty endovascular thrombectomy procedures were included. Operators and adjudicators had a pairwise agreement in 96 cases (73.8%). Krippendorff α was 0.712. Multivariate analysis showed endovascular thrombectomy overnight (odds ratio [OR]=3.84 [95% CI, 1.22­12.1]), lacking frontal (OR, 5.66 [95 CI, 1.36­23.6]), or occipital (OR, 7.18 [95 CI, 2.12­24.3]) region reperfusion, and higher operator mTICI scores (OR, 2.16 [95 CI, 1.16­4.01]) were predictive of incorrectly scoring mTICI intraprocedurally. With dichotomized mTICI scores, increasing number of passes was associated with increased risk of operator error (OR, 1.93 [95 CI, 1.22­3.05]). Conclusions: In our study, mTICI disagreement between operator and adjudicators was observed in 26.2% of cases. Interventions that took place between 22:30 and 4:00, featured frontal or occipital region nonperfusion, higher operator mTICI scores, and increased number of passes had higher odds of intraprocedural mTICI inaccuracy.

Effect of Hispanic Status in Mechanical Thrombectomy Outcomes After Ischemic Stroke: Insights From STAR.

Background and Purpose: Epidemiological studies have shown racial and ethnic minorities to have higher stroke risk and worse outcomes than non-Hispanic Whites. In this cohort study, we analyzed the STAR (Stroke Thrombectomy and Aneurysm Registry) database, a multi-institutional database of patients who underwent mechanical thrombectomy for acute large vessel occlusion stroke to determine the relationship between mechanical thrombectomy outcomes and race. Methods: Patients who underwent mechanical thrombectomy between January 2017 and May 2020 were analyzed. Data included baseline characteristics, vascular risk factors, complications, and long-term outcomes. Functional outcomes were assessed with respect to Hispanic status delineated as non-Hispanic White (NHW), non-Hispanic Black (NHB), or Hispanic patients. Multivariate analysis was performed to identify variables associated with unfavorable outcome or modified Rankin Scale ≥3 at 90 days. Results: Records of 2115 patients from the registry were analyzed. Median age of Hispanic patients undergoing mechanical thrombectomy was 60 years (72­84), compared with 63 years (54­74) for NHB, and 71 years (60­80) for NHW patients (P<0.001). Hispanic patients had a higher incidence of diabetes (41%; P<0.001) and hypertension (82%; P<0.001) compared with NHW and NHB patients. Median procedure time was shorter in Hispanics (36 minutes) compared to NHB (39 minutes) and NHW (44 minutes) patients (P<0.001). In multivariate analysis, Hispanic patients were less likely to have favorable outcome (odds ratio, 0.502 [95% CI, 0.263­0.959]), controlling for other significant predictors (age, admission National Institutes Health Stroke Scale, onset to groin time, number of attempts, procedure time). Conclusions: Hispanic patients are less likely to have favorable outcome at 90 days following mechanical thrombectomy compared to NHW or NHB patients. Further prospective studies are required to validate our findings.

Current Status of Endovascular Treatment for Acute Large Vessel Occlusion in China: A Real-World Nationwide Registry.

BACKGROUND AND PURPOSE: The benefit of endovascular treatment (EVT) for large vessel occlusion in clinical practice in developing countries like China needs to be confirmed. The aim of the study was to determine whether the benefit of EVT for acute ischemic stroke in randomized trials could be generalized to clinical practice in Chinese population. METHODS: We conducted a prospective registry of EVT at 111 centers in China. Patients with acute ischemic stroke caused by imaging-confirmed intracranial large vessel occlusion and receiving EVT were included. The primary outcome was functional independence at 90 days defined as a modified Rankin Scale score of 0 to 2. Outcomes of specific subgroups in the anterior circulation were reported and logistic regression was performed to predict the primary outcome. RESULTS: Among the 1793 enrolled patients, 1396 (77.9%) had anterior circulation large vessel occlusion (median age, 66 [56-73] years) and 397 (22.1%) had posterior circulation large vessel occlusion (median age, 64 [55-72] years). Functional independence at 90 days was reached in 45% and 44% in anterior and posterior circulation groups, respectively. For anterior circulation population, underlying intracranial atherosclerotic disease was identified in 29% of patients, with higher functional independence at 90 days (52% versus 44%; P=0.0122) than patients without intracranial atherosclerotic disease. In the anterior circulation population, after adjusting for baseline characteristics, procedure details, and early outcomes, the independent predictors for functional independence at 90 days were age <66 years (odds ratio [OR], 1.733 [95% CI, 1.213-2.476]), time from onset to puncture >6 hours (OR, 1.536 [95% CI, 1.065-2.216]), local anesthesia (OR, 2.194 [95% CI, 1.325-3.633]), final modified Thrombolysis in Cerebral Infarction 2b/3 (OR, 2.052 [95% CI, 1.085-3.878]), puncture-to-reperfusion time ≤1.5 hours (OR, 1.628 [95% CI, 1.098-2.413]), and National Institutes of Health Stroke Scale score 24 hours after the procedure <11 (OR, 9.126 [95% CI, 6.222-13.385]). CONCLUSIONS: Despite distinct characteristics in the Chinese population, favorable outcome of EVT can be achieved in clinical practice in China. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03370939.

Use of quantitative angiographic methods with a data-driven model to evaluate reperfusion status (mTICI) during thrombectomy.

PURPOSE: Intra-procedural assessment of reperfusion during mechanical thrombectomy (MT) for emergent large vessel occlusion (LVO) stroke is traditionally based on subjective evaluation of digital subtraction angiography (DSA). However, semi-quantitative diagnostic tools which encode hemodynamic properties in DSAs, such as angiographic parametric imaging (API), exist and may be used for evaluation of reperfusion during MT. The objective of this study was to use data-driven approaches, such as convolutional neural networks (CNNs) with API maps, to automatically assess reperfusion in the neuro-vasculature during MT procedures based on the modified thrombolysis in cerebral infarction (mTICI) scale. METHODS: DSAs from patients undergoing MTs of anterior circulation LVOs were collected, temporally cropped to isolate late arterial and capillary phases, and quantified using API peak height (PH) maps. PH maps were normalized to reduce injection variability. A CNN was developed, trained, and tested to classify PH maps into 2 outcomes (mTICI 0,1,2a/mTICI 2b,2c,3) or 3 outcomes (mTICI 0,1,2a/mTICI 2b/mTICI 2c,3), respectively. Ensembled networks were used to combine information from multiple views (anteroposterior and lateral). RESULTS: The study included 383 DSAs. For the 2-outcome classification, average accuracy was 81.0% (95% CI, 79.0-82.9%), and the area under the receiver operating characteristic curve (AUROC) was 0.86 (0.84-0.88). For the 3-outcome classification, average accuracy was 64.0% (62.0-66.0), and AUROC values were 0.85 (0.83-0.87), 0.74 (0.71-0.77), and 0.78 (0.76-0.81) for the mTICI 0,1,2a, mTICI 2b, and mTICI 2c,3 classes, respectively. CONCLUSION: This study demonstrated the feasibility of using hemodynamic information in API maps with data-driven models to autonomously assess intra-procedural reperfusion during MT.

Semi-automated measurement of vascular tortuosity and its implications for mechanical thrombectomy performance.

PURPOSE: Few studies have examined the geometry of endovascular mechanical thrombectomy pathways. Here we examine the tortuosity and angulations of catheter pathways from the aortic arch to the termination of the internal carotid artery (ICA) and its association with thrombectomy performance. METHODS: We included 100 consecutive anterior circulation large vessel occlusion thrombectomy patients over 12 months. Computed tomography angiograms (CTA) were used for 3D segmentation of catheter pathway from the aortic arch to ICA termination. Tortuosity index (TI) and angulations of the catheter pathway were measured in a semi-automated fashion. TI and angulation degree were compared between sides and correlated with age and procedural measures. RESULTS: We analyzed 188 catheter pathways in 100 patients. Severe angulation (≤ 30°) was present in 5.8% and 39.4% of common carotid artery (CCA) and extracranial ICA segments, respectively. Five pathways (2.6%) had 360° loop. CCA and extracranial ICA tortuosity had a weak but significant correlation with age (r = 0.17, 0.21, p value = 0.05, 0.02 respectively), time from groin puncture to the site of occlusion (r = 0.29, 0.25, p values = 0.008, 0.026 respectively), and fluoroscopy time (r = 0.022, 0.31, p values = 0.016, 0.001 respectively). There was a significant difference in the pattern of angulation (p value = 0.04) and tortuosity between right and left side in CCA segment (TI = 0.20 ± 0.086 vs. 0.15 ± 0.82, p value < 0.001). CONCLUSIONS: There was a significant difference in CCA angulation between right and left sides. TI of extracranial CCA and ICA correlated with age and influenced time from groin puncture to the occlusion site and total fluoroscopy time.

Cell-Based Therapy for Stroke: Musing With Muse Cells.

Stem cell-based regenerative therapies may rescue the central nervous system following ischemic stroke. Mesenchymal stem cells exhibit promising regenerative capacity in in vitro studies but display little to no incorporation in host tissue after transplantation in in vivo models of stroke. Despite these limitations, clinical trials using mesenchymal stem cells have produced some functional benefits ascribed to their ability to modulate the host's inflammatory response coupled with their robust safety profile. Regeneration of ischemic brain tissue using stem cells, however, remains elusive in humans. Multilineage-differentiating stress-enduring (Muse) cells are a distinct subset of mesenchymal stem cells found sporadically in connective tissue of nearly every organ. Since their discovery in 2010, these endogenous reparative stem cells have been investigated for their therapeutic potential against a variety of diseases, including acute myocardial infarction, stroke, chronic kidney disease, and liver disease. Preclinical studies have exemplified Muse cells' unique ability mobilize, differentiate, and engraft into damaged host tissue. Intravenously transplanted Muse cells in mouse lacunar stroke models afforded functional recovery and long-term engraftment into the host neural network. This mini-review article highlights these biological properties that make Muse cells an exceptional candidate donor source for cell therapy in ischemic stroke. Elucidating the mechanism behind the therapeutic potential of Muse cells will undoubtedly help optimize stem cell therapy for stroke and advance the field of regenerative medicine.

Size of ruptured intracranial aneurysms: a systematic review and meta-analysis.

BACKGROUND: There is wide variation in the reported size of ruptured intracranial aneurysms and methods of size estimation. There is widespread belief that small aneurysms < 7 mm do not rupture. Therefore, we performed a systematic review and meta-analysis of the literature to determine the size of ruptured aneurysms according to aneurysm locations and methods of size estimation. METHODS: We searched PubMed, Cochrane, CINAHL, and EMBASE databases using a combination of Medical Subject Headings (MeSH) terms. We included articles that reported mean aneurysm size in consecutive series of ruptured intracranial. We excluded studies limited to a specific aneurysm location or type. The random-effects model was used to calculate overall mean size and location-specific mean size. We performed meta-regression to explain observed heterogeneity and variation in reported size. RESULTS: The systematic review included 36 studies and 12,609 ruptured intracranial aneurysms. Overall mean aneurysm size was 7.0 mm (95% confidence interval [CI 6.2-7.4]). Pooled mean size varied with location. Overall mean size of 2145 ruptured anterior circulation aneurysms was 6.0 mm (95% CI 5.6-6.4, residual I2 = 86%). Overall mean size of 743 ruptured posterior circulation aneurysms was 6.2 mm (95% CI 5.3-7.0, residual I2 = 93%). Meta-regression identified aneurysm location and definition of size (i.e., maximum dimension vs. aneurysm height) as significant determinants of aneurysm size reported in the studies. CONCLUSIONS: The mean size of ruptured aneurysms in most studies was approximately 7 mm. The general wisdom that aneurysms of this size do not rupture is incorrect. Location and size definition were significant determinants of aneurysm size.

Large Vessel Occlusion in Acute Ischemic Stroke Patients: A Dual-Center Estimate Based on a Broad Definition of Occlusion Site.

BACKGROUND: Accurate assessment of the frequency of large vessel occlusion (LVO) is important to determine needs for neurointerventionists and thrombectomy-capable stroke facilities. Current estimates vary from 13% to 52%, depending on acute ischemic stroke (AIS) definition and methods for AIS and LVO determination. We sought to estimate LVO prevalence among confirmed and suspected AIS patients at 2 comprehensive US stroke centers using a broad occlusion site definition: internal carotid artery (ICA), first and second segments of the middle cerebral artery (MCA M1,M2), the anterior cerebral artery, vertebral artery, basilar artery, or the proximal posterior cerebral artery. METHODS: We analyzed prospectively maintained stroke databases of patients presenting to the centers between January and December 2017. ICD-10 coding was used to determine the number of patients discharged with an AIS diagnosis. Computed tomography angiography (CTA) or magnetic resonance angiography (MRA) was reviewed to determine LVO presence and site. Percentages of patients with LVO among the confirmed AIS population were reported. RESULTS: Among 2245 patients with an AIS discharge diagnosis, 418 (18.6%:95% confidence interval [CI] 17.3%-20.0%) had LVO documented on CTA or MRA. Most common occlusion site was M1 (n=139 [33.3%]), followed by M2 (n=114 [27.3%]), ICA (n=69[16.5%]), and tandem ICA-MCA lesions (n=44 [10.5%]). Presentation National Institutes of Health Stroke Scale scores were significantly different for different occlusion sites (P=.02). CONCLUSIONS: The LVO prevalence in our large series of consecutive AIS patients was 18.6% (95% CI 17.3%-20.0%). Despite the use of a broad definition, this estimate is less than that reported in most previous studies.

Impact of Stent Retriever Size on Clinical and Angiographic Outcomes in the STRATIS Stroke Thrombectomy Registry.

Background and Purpose- The safety and efficacy of mechanical thrombectomy in patients with acute ischemic stroke has been demonstrated. However, the impact of stent retriever size on clinical and angiographic outcomes is not well established. Methods- This was a retrospective ad hoc analysis of data from the STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) registry-a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever. An independent core laboratory, blinded to clinical outcomes, reviewed all procedures and angiographic data to classify stent retriever size, targeted clot location, recanalization after each pass, and the number of stent retriever passes. The primary angiographic end point was first-pass effect (FPE) as determined by a core laboratory and defined as achieving near-complete revascularization (modified Thrombolysis in Cerebral Infarction ≥2c) after the first pass without the use of rescue therapy. Rates of modified FPE were also assessed, defined as meeting all criteria for FPE but achieving modified Thrombolysis in Cerebral Infarction ≥2b after first pass. The primary clinical end point was functional independence (modified Rankin Scale, 0-2) at 3 months as determined on-site. Outcome comparisons were made across the stent retriever size groups and adjusted for baseline characteristics. Results- Of 715 patients, a 4×20 stent retriever was used in 201 (28%) patients, 4×40 was used in 270 (38%) patients, and 6×30 was used in 244 (34%) patients. The 4×40 group had the highest rate of FPE ( P=0.003 versus 6×30) and modified FPE ( P=0.038 versus 4×20; P=0.0001 versus 6×30). Final revascularization was not significantly different across the groups, and there were no significant differences in functional dependence or mortality at 90 days post-procedure. Use of the longer stent retriever (4×40) was an independent predictor of achieving modified FPE ( P=0.037 versus 6×30; P=0.037 versus 4×20). Conclusions- The longer stent retriever (4×40) demonstrated the highest rate FPE and modified FPE compared with larger diameter or shorter stent retrievers, suggesting that their routine use may improve early revascularization success. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Site Experience and Outcomes in the Trevo Acute Ischemic Stroke (TRACK) Multicenter Registry.

Background and Purpose- It remains unclear how experience influences outcomes after the advent of stent retriever technology. We studied the relationship between site experience and outcomes in the Trevo Acute Ischemic Stroke multicenter registry. Methods- The 24 sites that enrolled patients in the Trevo Acute Ischemic Stroke registry were trichotomized into low-volume (<2 cases/month), medium-volume (2-4 cases/month), and high-volume centers (>4 cases/month). Baseline features, imaging, and clinical outcomes were compared across the 3 volume strata. A multivariable analysis was performed to assess whether outcomes were influenced by site volumes. Results- A total of 624 patients were included and distributed as low- (n=188 patients, 30.1%), medium- (n=175, 28.1%), and high-volume (n=261, 41.8%) centers. There were no significant differences in terms of age (mean, 66±16 versus 67±14 versus 65±15; P=0.2), baseline National Institutes of Health Stroke Scale (mean, 17.6±6.5 versus 16.8±6.5 versus 17.6±6.9; P=0.43), or occlusion site across the 3 groups. Median (interquartile range) times from stroke onset to groin puncture were 266 (181.8-442.5), 239 (175-389), and 336.5 (221.3-466.5) minutes in low-, medium-, and high-volume centers, respectively (P=0.004). Higher efficiency and better outcomes were seen in higher volume sites as demonstrated by shorter procedural times (median, 97 versus 67 versus 69 minutes; P<0.001), higher balloon guide catheter use (40% versus 36% versus 59%; P≤0.0001), and higher rates of good outcome (90-day modified Rankin Scale [mRS], ≤2; 39% versus 50% versus 53.4%; P=0.02). There were no appreciable differences in symptomatic intracranial hemorrhage or 90-day mortality. After adjustments in the multivariable analysis, there were significantly higher chances of achieving a good outcome in high- versus low-volume (odds ratio, 1.67; 95% CI, 1.03-2.7; P=0.04) and medium- versus low-volume (odds ratio, 1.75; 95% CI, 1.1-2.9; P=0.03) centers, but there were no significant differences between high- and medium-volume centers (P=0.86). Conclusions- Stroke center volumes significantly influence efficiency and outcomes in mechanical thrombectomy.

Direct Aspiration versus Stent Retriever Thrombectomy for Acute Stroke: A Systematic Review and Meta-Analysis in 9127 Patients.

BACKGROUND: The two most common approaches to thrombectomy of emergent large vessel occlusion (direct aspiration and primary stent retriever thrombectomy) have been extensively studied; however, the detailed benefit and risk comparison is largely unknown. OBJECTIVE: To conduct a systematic review and meta-analysis to compare radiographic and clinical outcomes between the use of primary stent retrievers and direct aspiration in management of acute ischemic stroke. METHODS: PubMed database was searched for studies between September 1, 2012 and December 31, 2017 with acute ischemic stroke patients. RESULTS: We identified 64 studies with 6875 patients in the primary stent retriever group and 25 studies with 2252 patients in the aspiration group. Primary aspiration alone, without the need of rescue stent retriever devices within the aspiration cohort, was performed in 65% of 2252 patients. There was no difference in the distribution of emergent large vessel occlusion based on occlusion site, age, baseline National Institutes of Health Stroke Scale, or the use of intravenous tPA (P = .19, .051, .23, and .093, respectively). Successful recanalization rates, defined as thrombolysis in cerebral Infarction 2b/3, were significantly higher in the aspiration group than the primary stent retriever group (89% versus 80%, P < .0001). No significant difference in good clinical outcome, defined as modified Rankin scale 0-2 (aspiration 52% versus stent 48%, P = .13), symptomatic intracerebral hemorrhage (aspiration 5.6% versus stent 7.2%, P = .07), and mortality at 3 months (aspiration 15% versus stent 19%, P = .10). CONCLUSIONS: Both aspiration-first (including the subsequent use of stent retriever) and primary stent retriever thrombectomy approaches are equally effective in achieving good clinical outcomes. Our study suggests that direct aspiration with or without subsequent use of stent retriever is a safe and effective alternative to primary stent retriever in acute ischemic stroke.

ASPECTS (Alberta Stroke Program Early CT Score) Measurement Using Hounsfield Unit Values When Selecting Patients for Stroke Thrombectomy.

BACKGROUND AND PURPOSE: The ASPECTS (Alberta Stroke Program Early CT Score) is a quantitate score that measures the extent of early ischemic changes. Our aim was to investigate how measurement of ASPECTS using Hounsfield unit (HU) values on initial noncontrast head computerized tomography (CT) correlates with the extent of final infarct on follow-up imaging. METHODS: Cases of acute stroke from the middle cerebral artery M1 occlusion in which complete recanalization (TICI [Thrombolysis in Cerebral Infarction] 3) was achieved were included for analysis. Using HU ratio (HU affected/HU control hemisphere) and HU difference (HU control-HU affected hemisphere) values, ASPECTS was measured on initial CT imaging and correlated with final ASPECTS at 24 hours. The study cohort consisted of 41 patients with acute stroke from the M1 occlusion. The mean time from stroke symptoms onset to baseline head CT imaging was 264 minutes and from CT to TICI 3 recanalization was 142 minutes. RESULTS: HU ratio within the 0.94 to 0.96 ranges showed the highest correlation coefficient and lowest mean and median errors with the final ASPECTS. The difference of 2.0 HU between the 2 hemispheres demonstrated the higher correlation coefficient (r=0.71; P<0.0001) and the lowest mean and median absolute errors (1.4 and 1, respectively). CONCLUSIONS: We established a simple algorithm for rapid and accurate assessment of ASPECTS on baseline CT imaging to predict the extent of final stroke in patients with emergent large vessel occlusion who undergo endovascular revascularization.

Predictive Value of RAPID Assessed Perfusion Thresholds on Final Infarct Volume in SWIFT PRIME (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment).

BACKGROUND AND PURPOSE: Computed tomography perfusion imaging can estimate the size of the ischemic core, which can be used for the selection of patients for endovascular therapy. The relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) thresholds chosen to identify ischemic core influence the accuracy of prediction. We aimed to analyze the accuracy of various rCBV and rCBF thresholds for predicting the 27-hour infarct volume using RAPID automated analysis software from the SWIFT PRIME trial (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment) data. METHODS: Patients from the SWIFT PRIME study who achieved complete reperfusion based on time until the residue function reached its peak >6 s perfusion maps obtained at 27 hours were included. Patients from both the intravenous tissue-type plasminogen activator only and endovascular groups were included in analysis. Final infarct volume was determined on magnetic resonance imaging (fluid-attenuated inversion recovery images) or computed tomography scans obtained 27 hours after symptom onset. The predicted ischemic core volumes on rCBV and rCBF maps using thresholds ranging between 0.2 and 0.8 were compared with the actual infarct volume to determine the most accurate thresholds. RESULTS: Among the 47 subjects, the following baseline computed tomography perfusion thresholds most accurately predicted the actual 27-hour infarct volume: rCBV=0.32, median absolute error (MAE)=9 mL; rCBV=0.34, MAE=9 mL; rCBF=0.30, MAE=8.8 mL; rCBF=0.32, MAE=7 mL; and rCBF=0.34, MAE=7.3. CONCLUSIONS: Brain regions with rCBF 0.30 to 0.34 or rCBV 0.32 to 0.34 thresholds provided the most accurate prediction of infarct volume in patients who achieved complete reperfusion with MAEs of ≤9 mL. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01657461.

Neuroimaging of Cavernous Malformations.

PURPOSE OF REVIEW: Cerebral cavernous malformations (CCMs) are common vascular abnormalities often discovered on imaging as an incidental finding. The most common clinical presentations of CCMs include seizure, headache, focal neurological deficits, and intracranial hemorrhage. This article discusses the most recent guidelines including imaging diagnostic criteria and radiographic standards of CCMs and reviews the utility of currently available imaging techniques. RECENT FINDINGS: Gradient echo T2*-weighted imaging and susceptibility-weighted imaging are the recommended imaging protocols for evaluation of suspected CCMs. Diffusion tensor imaging-based tractography provides visualization of the eloquent white matter tracks in the brain. This imaging is increasingly used in clinical practice to assist in selecting the optimal surgical approach, especially for brainstem lesions. Quantitative susceptibility mapping and dynamic contrast-enhanced quantitative perfusion are presently considered experimental. Its proposed value might prove helpful in the future to monitor disease activity and response to treatments. The choice of imaging modality of CCMs depends on the goals the clinician expects to achieve, such as establishing the initial diagnosis, follow-up and monitoring disease activity, preoperative, intraoperative, and postoperative evaluation, or research and experimental work on patients with CCM.

Prolapse of the Pipeline embolization device in aneurysms: incidence, management, and outcomes.

OBJECTIVE The Pipeline embolization device (PED) is frequently used in the treatment of anterior circulation aneurysms, especially around the carotid siphon, with generally excellent results. However, the PED has its own unique technical challenges, including the occurrence of device foreshortening or migration leading to prolapse into the aneurysm. The authors sought to determine the incidence of this phenomenon, the rescue strategies, and outcomes. METHODS Four institutional databases of neuroendovascular procedures were reviewed for cases of intracranial aneurysms treated with PEDs. Patient and aneurysm data as well as angiographic imaging were reviewed for all cases involving device prolapse into the aneurysm. RESULTS A total of 413 intracranial aneurysms were treated with PEDs during the study period, by 5 neurointerventionalists. Large and giant aneurysms (≥ 2 cm) accounted for 32 of these aneurysms. Among these 32 PEDs, prolapse into the aneurysm occurred in 3 patients, with 1 of these PEDs successfully rescued and the other 2 left in situ. No patients suffered any severe complications. The 2 patients in whom the PEDs were left in situ remained on antiplatelet therapy. CONCLUSIONS The PED may foreshorten or migrate during or after deployment, leading to prolapse into the aneurysm. This phenomenon appears to be associated with large and giant aneurysms, vessel tortuosity, short landing zones, and use of balloon angioplasty. Future study and follow-up is needed to further evaluate this phenomenon, but some of the observations and techniques described in this paper may help to prevent or salvage prolapsed devices.