Neurothrombectomy for Acute Ischemic Stroke Across Clinical Trial Design and Technique: A Single Center Pooled Analysis.

Introduction: The practice of endovascular therapy has evolved dramatically over the last 10 years with randomized clinical trials investigating the benefit of thrombectomy in select patient populations based on time of presentation, imaging criteria, and procedural technique. We sought to understand the benefit of thrombectomy in patients treated within the context of a clinical trial at a single academic center. Methods: Patient-level data recorded in case forms and core-lab adjudicated data were analyzed from patients enrolled in RCTs investigating the benefit of endovascular thrombectomy over medical management (IMSIII, MR RESCUE, ESCAPE, SWIFT PRIME, and DAWN) between 2007 and 2017 at a single academic referral center. Results: A total of 134 patients (intervention group, n = 81; medical group, n = 53) were identified across five clinical trials (IMSIII, n = 46; MR RESCUE, n = 4; ESCAPE, n = 24; SWIFT PRIME, n = 14; DAWN, n = 46). There were no significant differences between the treatment arm and control arm in terms of age, gender, baseline NIHSS, ASPECTS, and site of occlusion. Rates of good outcome were superior in the intervention group with early neurological recovery (NIHSS of 0-1 or increase NIHSS of 8 points at 24 h) at a higher rate of 49% vs. 17% (p = <0.001) and higher rates of functional independence (90 day mRS 0-2 of 53% vs. 26%, p = 0.002). In multivariate logistic regression analysis, lower NIHSS and younger age were predictors of good outcome. There were comparable rates of good outcome irrespective of clinical trial, imaging selection criteria (CTP vs. MRI), early vs. late time window (0-6 h vs. 6-24 h) and procedural technique (Merci vs. Solitaire/Trevo device). There were no differences in rates of sICH, PH-2 or mortality in the intervention group vs. medical group. Conclusions: At a large academic center, the benefit of endovascular therapy over medical therapy is observed irrespective of clinical trial design, patient selection or procedural technique.

Comparison of Quantitative and Qualitative Oxygen Extraction Fraction (OEF) in Acute Stroke Patients with Large Vessel Occlusion.

The superficial temporal artery-middle cerebral artery bypass (STA-MCA) bypass surgery developed by Donaghy and Yarsagil in 1967 provided relief for patients with acute stroke and large vessel occlusive vascular disease. Early reports showed low morbidity and good outcomes. However, a large clinical trial in 1985 reported a failure of extracranial-intracranial (EC/IC) bypass to show benefit in reducing the risk of stroke compared to best medical treatment. Problems with the study included cross overs to surgery from best medical treatment, patients unwilling to be randomized and chose EC/IC surgery, and loss of patients to follow-up. Most egregious is the fact that the study did not attempt to identify and select the patients at high risk for a second stroke. Based on these shortcomings of the EC/IC bypass study, a carotid occlusion surgery study (COSS) was proposed by Dr. William Powers and colleagues using qualitative hemispheric oxygen extraction fraction (OEF) by positron emission tomography (PET) between the contralateral and ipsilateral hemispheres with a ratio of 1.16 indicative of hemodynamic compromise. To increase patient enrollment, several compromises were made mid study. First. The ratio threshold was lowered to 1.12 and the level of occlusion in the carotid reduced from 70% to 60%. Despite these compromises the study was closed for futility, apparently because the stroke rate in the medically treated group was too low. Thus, the question as to the benefit of EC/IC bypass surgery remains unresolved. In our NIH funded study Quantitative Occlusive Vascular Disease Study (QUOVADIS), we used quantitative OEF to evaluate stroke risk and compared it to the qualitative count-rate ratio method used in the COSS study and found that these two methods did not identify the same patients at increased risk for stroke, which may explain the reason for the failure of the COSS study as our results show that qualitative OEF ratios do not identify the same patients as quantitative OEF.

Interfacility Transfer Directly to the Neuroangiography Suite in Acute Ischemic Stroke Patients Undergoing Thrombectomy.

BACKGROUND AND PURPOSE: In patients identified at referring facilities with acute ischemic stroke caused by a large vessel occlusion, bypassing the emergency department (ED) with direct transport to the neuroangiography suite may safely shorten reperfusion times. METHODS: We conducted a single-center retrospective review of consecutive patients transferred to our facility for consideration of endovascular therapy. Patients were identified as admitted directly to the neuroangiography suite (DAN), transferred to the ED before intra-arterial therapy (ED-IA), and transferred to the ED but did not receive IA therapy (ED-IV). RESULTS: A retrospective review of a prospectively maintained database of transfer patients between January 2013 and October 2016 with large vessel occlusions identified 108 ED-IV patients and 261 patients who underwent mechanical thrombectomy (DAN=111 patients and ED-IA=150 patients). There were no differences in baseline characteristics among the 3 groups. The median computed tomography ASPECTS (Alberta Stroke Program Early CT Score) was lower in the ED-IV group versus the ED-IA and DAN groups (8 versus 9; P=0.001). In the DAN versus ED-IA cohort, there were comparable rates of TICI2b/3 recanalization and access to recanalization time. There was significantly faster hospital arrival to groin access time in the DAN cohort (81 minutes versus 22 minutes; P=0.001). Functional independence at 90 days was comparable in the DAN versus ED-IA cohorts but worse in the ED-IV group (43% versus 44% versus 22%; P=0.001). CONCLUSIONS: DAN is safe, feasible, and associated with faster times of hospital arrival to recanalization. The clinical benefit of this approach should be assessed in a prospective randomized trial.

Three-Dimensional Representations of Objects in Dorsal Cortex are Dissociable from Those in Ventral Cortex.

An established conceptualization of visual cortical function is one in which ventral regions mediate object perception while dorsal regions support spatial information processing and visually guided action. This division has been contested by evidence showing that dorsal regions are also engaged in the representation of object shape, even when actions are not required. The critical question is whether these dorsal, object-based representations are dissociable from ventral representations, and whether they play a functional role in object recognition. We examined the neural and behavioral profile of patients with impairments in object recognition following ventral cortex damage. In a functional magnetic resonanace imaging experiment, the blood oxygen level-dependent response in the ventral, but not dorsal, cortex of the patients evinced less sensitivity to object 3D structure compared with that of healthy controls. Consistently, in psychophysics experiments, the patients exhibited significant impairments in object perception, but still revealed residual sensitivity to object-based structural information. Together, these findings suggest that, although in the intact system there is considerable crosstalk between dorsal and ventral cortices, object representations in dorsal cortex can be computed independently from those in ventral cortex. While dorsal representations alone are unable to support normal object perception, they can, nevertheless, support a coarse description of object structural information.

Telestroke Imaging: A Review.

The use of telecommunications technology to provide the healthcare services, telemedicine, has been in use since the 1860s. The use of technology has ranged from providing medical care to far-off places during wartimes to monitoring physiological measurements of astronauts in space. Since the 1990s, reports have been published on diagnoses of neurological diseases with the use of video links. Studies confirm that the neurological examinations, including the National Institutes of Health Stroke Scale, performed during teleneurology are dependable. The transfer of stroke patients in rural hospitals to bigger medical centers delays treatment while there exists current and projected shortage of neurologists. Telestroke provides the solution. Patients suspected of acute stroke need a noncontrast computerized tomography (CT) scan for tissue plasminogen activator administration. Vascular imaging such as CT angiography, magnetic resonance angiography, and digital subtraction angiography can help show large-vessel occlusion or critical stenosis responsive to endovascular therapy. A standard protocol can be followed to decide a vascular modality of choice, considering advantages and disadvantages of each imaging modality. Telestroke solves the problems of distance and of shortage of neurologists. Neuroimaging plays a vital role in the delivery of telestroke, and the telestroke doctor should be comfortable with making a decision on selecting an appropriate vascular imaging modality.

The prognostic significance of troponin I elevation in acute ischemic stroke.

BACKGROUND: The significance of cardiac troponin I (TnI) levels in patients with acute ischemic stroke remains unclear. METHODS: Data were prospectively collected on 1718 patients with acute ischemic stroke (2009-2010). Patients with positive TnI (peak TnI ≥0.1 µg/L) were assigned to the myocardial infarction (MI) group if they met diagnostic criteria. The remaining patients with positive TnI were assigned to the no-MI group. Patients were followed up for 1.4 ± 1.1 years. Primary outcome was inhospital and long-term all-cause mortality. RESULTS: Positive TnI was present in 309 patients (18%), 119 of whom (39%) were classified as having MI. Positive TnI was independently associated with older age, hypertension, smoking, peripheral arterial disease, heart failure, higher systolic blood pressure, higher serum creatinine, and lower heart rate (P < .01). Patients with MI had the highest inpatient mortality (P < .001) and the lowest survival rate by Kaplan-Meier analysis (P < .0001). Peak TnI greater than or equal to 0.5 µg/L, particularly if satisfying criteria for MI, was independently associated with long-term mortality (P < .0001); peak TnI less than 0.5 µg/L alone was not when adjusted for covariates. CONCLUSION: Positive TnI greater than or equal to 0.5 µg/L in patients with acute ischemic stroke was independently associated with worse outcomes. Patients with diagnosis of MI represent a particularly high-risk subgroup.

Aspirin Response Test role in platelet transfusion following intracerebral hemorrhage.

OBJECTIVES: Spontaneous intracerebral hemorrhage (ICH) results in high morbidity and mortality. A target for therapy might be hematoma expansion, which occurs in a significant proportion of patients, and can be exacerbated by antiplatelet medications, such as aspirin. It is not clear whether platelet transfusion neutralizes aspirin. The Aspirin Response Test (ART) is commonly ordered in this patient population, but it is not clear whether the results of this test can help select patients for transfusion of platelets. The aim of our study is to investigate whether a selected group of ICH patients, those with reduced platelet activity ("aspirin responders"), will benefit from platelet transfusion. MATERIALS AND METHODS: This retrospective study included 63 patients who were taking aspirin but no other antithrombotic medication prior to the ICH. For each patient, we measured hematoma size by head CT on admission and compared with follow-up head CT 1 day later. RESULTS: In the general cohort, 41% of transfused patients and 29% of non-transfused patients had a hematoma expansion. In the "aspirin responders" group, 46% of transfused patients and 22% of non-transfused patients had an expansion. CONCLUSIONS: Our data suggest that platelet transfusion following an ICH in "aspirin responders" does not reduce hematoma expansion rates in those patients. A larger prospective study is needed.

Predictors of Outcome in Patients Presenting with Acute Ischemic Stroke and Mild Stroke Scale Scores.

BACKGROUND: Although National Institutes of Health Stroke Scale (NIHSS) is a known predictor of outcome in acute ischemic stroke, there are other factors like age, ambulatory status, and ability to swallow that may be predictors of outcome but are not assessed by the traditional NIHSS. The aim of this retrospective review was to identify predictors of outcome in mild ischemic stroke. METHODS: Discharge outcomes from patients who presented to our large academic stroke center with acute ischemic stroke from 2005 to 2013 were retrospectively reviewed. Of 7189 patients reviewed, 2597 had initial NIHSS less than 5. Outcome measures were modified Rankin Scale (MRS) score 0-1 and discharge to home. RESULTS: In all, 65% of patients with NIHSS 0-4 were discharged directly home independent of treatment. Of those patients discharged to home, 74% were able to ambulate independently and 98% passed their dysphagia screen. Of patients not discharged directly home, 66% were unable to ambulate independently and 21% did not pass their dysphagia screen. Multivariate logistic regression analysis revealed a significant effect of dysphagia screen (P = .001), ability to ambulate independently (P = .002), age (P = .016), and NIHSS (P = .005) on discharge to home but not MRS of 0-1 (P = .564). CONCLUSIONS: In patients with mild stroke scale scores defined as NIHSS 0-4, several factors including age, NIHSS, ambulatory status, and ability to swallow may be independent predictors of functional outcome and discharge home. These data support the development of a modified grading system for assessing functional outcome in mild stroke that considers these factors.

Outcomes after endovascular treatment for anterior circulation stroke presenting as wake-up strokes are not different than those with witnessed onset beyond 8†hours.

OBJECTIVE: Previous studies have suggested that patients with wake-up stroke (WUS) may have superior outcomes compared with patients with a witnessed late time of onset after revascularization. We sought to test this hypothesis in patients with anterior circulation large vessel occlusion stroke (ACLVOS) treated with endovascular therapy beyond 8 h from time last seen well (TLSW). METHODS: A single center retrospective review of a prospectively acquired database of consecutive patients was performed to identify patients presenting beyond 8 h of TLSW with radiographic evidence of ACLVOS, small core, and large penumbra who subsequently underwent endovascular treatment. RESULTS: We identified 206 patients. Patients were divided into two groups: (1) patients with WUS (38%, n=78) and (2) patients with witnessed onset beyond 8 h (62%, n=128). The groups were similar in age, baseline National Institutes of Health Stroke Scale score, TLSW to reperfusion, baseline infarct volume, and rate of successful recanalization. Rates of good outcome (modified Rankin Scale score of 0-2 at 90 days, 43% vs. 50%, p=0.3), parenchymal hematoma (9% vs. 5.5%, p=0.3), and final infarct volume (75.2 vs. 61.4 mL, p=0.6) were comparable. Multivariate analysis identified age (OR=0.95, 95% CI 0.91 to 0.99, p<0.042), successful recanalization (OR 6.0, 95% CI 1.5 to 23.5, p=0.009), and final infarct volume (OR 0.98, 95% CI 0.97 to 0.99, p<0.001) but not mode of presentation as predictors of favorable outcomes. CONCLUSIONS: Rates of good outcomes, parenchymal hematoma, and final infarct volumes following endovascular treatment may not be different in patients with WUS compared with patients with witnessed onset of symptoms beyond 8 h.

Impact of telemedicine implementation in thrombolytic use for acute ischemic stroke: the University of Pittsburgh Medical Center telestroke network experience.

BACKGROUND: Intravenous thrombolysis is the only therapy for acute ischemic stroke that is approved by the US Food and Drug Association. The use of telemedicine in stroke makes it possible to bring the expertise of academic stroke centers to underserved areas, potentially increasing the quality of stroke care. METHODS: All consecutive admissions for stroke were reviewed for 1 year before telemedicine implementation and for variable periods thereafter. A retrospective review identified 2588 admissions for acute stroke between March 2005 and December 2008 at 12 hospitals participating in a telestroke network, including 919 patients before telemedicine was available and 1669 patients after telemedicine was available. The primary outcome measure was the rate of intravenous tissue plasminogen activator (IV tPA) use before and after telemedicine implementation. RESULTS: One hundred thirty-nine patients received IV tPA in both study phases, with 26 (2.8%) patients treated before starting telemedicine and 113 (6.8%) after starting telemedicine (P < .001). Incorrect treatment decisions occurred 7 times (0.39%), with 2 (0.2%) pretelemedicine and 5 (0.3%) posttelemedicine (P = .70). Arrivals within 3 hours from symptom onset were more frequent in the posttelemedicine compared to the pretelemedicine phases (55 [6%] vs 159 [9.5%]; P = .002). Among the patients treated with IV tPA, symptomatic intracranial hemorrhage occurred in 2 patients (1 [10.7%] pretelemedicine vs 1 [1.8%] posttelemedicine; P = .34). CONCLUSIONS: Telestroke implementation was associated with an increased rate of thrombolytic use in remote hospitals within the telemedicine network.

Final infarct volume is a stronger predictor of outcome than recanalization in patients with proximal middle cerebral artery occlusion treated with endovascular therapy.

BACKGROUND AND PURPOSE: The rationale for recanalization therapy in acute ischemic stroke is to preserve brain through penumbral salvage and thus improve clinical outcomes. We sought to determine the relationship between recanalization, clinical outcomes, and final infarct volumes in acute ischemic stroke patients presenting with middle cerebral artery occlusion who underwent endovascular therapy and post-procedure magnetic resonance imaging. METHODS: We identified 201 patients with middle cerebral artery occlusion. Patients with other occlusive lesions were excluded. Baseline clinical/radiological characteristics, procedural outcomes (including thrombolysis in cerebral infarction scores), clinical outcome scores (modified Rankin scores), and final infarct volumes on diffusion weighted imaging were retrospectively analyzed from a prospectively collected database. Favorable outcome is defined as 90-day modified Rankin score≤2. RESULTS: Successful recanalization (thrombolysis in cerebral infarction grade 2b or 3) was achieved in 63.2% and favorable outcomes in 46% of cases. Mean infarct volume was 50.1 mL in recanalized versus 133.9 mL in non-recanalized patients (P<0.01) and 40.4 mL in patients with favorable outcomes versus 111.8 in patients with unfavorable outcomes (P<0.01). In multivariate analysis, thrombolysis in cerebral infarction≥2b, baseline National Institute of Health Stroke Scale, Alberta Stroke Program Early Computed Tomography scores, and age were identified as independent predictors of outcome. However, when infarct volumes were included in the analysis only final infarct volume and age remained significantly associated. CONCLUSIONS: Successful recanalization leads to improved functional outcomes through a reduction in final infarct volumes. In our series, age and final infarct volume but not recanalization were found to be independent predictors of outcome, supporting the use of final infarct volume as surrogate marker of outcome in acute stroke trials.

Telestroke-guided intravenous tissue-type plasminogen activator treatment achieves a similar clinical outcome as thrombolysis at a comprehensive stroke center.

BACKGROUND AND PURPOSE: Telestroke networks offer an opportunity to increase tissue-type plasminogen activator use in community hospitals. METHODS: We compared 83 patients treated with intravenous tissue-type plasminogen activator by telestroke to 59 patients treated after in-person evaluation by the same neurologists at a tertiary care stroke center. Onset and door-to-treatment times and functional outcome at 90 days were obtained prospectively. Favorable outcome was defined as modified Rankin Scale score ≤2. RESULTS: Favorable outcome rates were comparable between the groups (42.1% versus 37.5%, P=0.7). There was no significant difference in the rate of symptomatic hemorrhage. CONCLUSIONS: Telestroke is a viable alternative to in-person evaluation when stroke expertise is not readily available.

Partial aortic occlusion for cerebral perfusion augmentation: safety and efficacy of NeuroFlo in Acute Ischemic Stroke trial.

BACKGROUND AND PURPOSE: Fewer than 5% of patients with acute ischemic stroke are currently treated, and there is need for additional treatment options. A novel catheter treatment (NeuroFlo) that increases cerebral blood flow was tested to 14 hours. METHODS: The Safety and Efficacy of NeuroFlo in Acute Ischemic Stroke trial is a randomized trial of the safety and efficacy of NeuroFlo treatment in improving neurological outcome versus standard medical management. The primary safety end point was the incidence of serious adverse events through 90 days. The primary efficacy end point on a modified intent-to-treat population was a global disability end point at 90 days. Secondary end points included mortality, intracranial hemorrhage, modified Rankin scale score outcome of 0 to 2, and modified Rankin scale shift analysis. RESULTS: Between October 2005 and January 2010, 515 patients were enrolled at 68 centers in 9 countries. The primary efficacy end point did not reach statistical significance (OR, 1.17; CI, 0.81-1.67; P=0.407). The primary safety end point did not show a difference in serious adverse events (P=0.923). Ninety-day mortality was 11.3% (26/230) in treatment and 16.3% (42/257) in control (P=0.087). Post hoc analyses showed that patients presenting within 5 hours (OR, 3.33; CI, 1.31-8.48), with NIHSS score 8 to 14 (OR, 1.80; CI, 0.99-3.30), or older than age 70 years (OR, 2.02; CI, 1.02-4.03) had better modified Rankin scale score outcomes of 0 to 2; additionally, there were fewer stroke-related deaths in treatment compared to control groups (7.4% = 17/230; 14.4% = 37/257). CONCLUSIONS: The trial met its primary safety end point but not its primary efficacy end point. Signals of treatment effect were suggested on all-cause mortality, in patients presenting early, older than age 70 years, or with moderate strokes, but these require confirmation. CLINICAL TRIAL REGISTRATION INFORMATION: URL: http://clinicaltrials.gov. Unique identifier: NCT00119717.

Endovascular treatment of tandem extracranial/intracranial anterior circulation occlusions: preliminary single-center experience.

BACKGROUND AND PURPOSE: Acute ischemic stroke due to tandem occlusions of the extracranial internal carotid artery and intracranial arteries has a poor natural history. We aimed to evaluate our single-center experience with endovascular treatment of this unique stroke population. METHODS: Consecutive patients with tandem occlusions of the internal carotid artery origin and an intracranial artery (ie, internal carotid artery terminus, M1 middle cerebral artery, or M2 middle cerebral artery) were studied retrospectively. Treatment consisted of proximal revascularization with angioplasty and stenting followed by intracranial intervention. Endpoints were recanalization of both extracranial and intracranial vessels (Thrombolysis In Myocardial Ischemia ≥2), parenchymal hematoma, and good clinical outcome (modified Rankin Scale ≤2) at 3 months. RESULTS: We identified 77 patients with tandem occlusions. Recanalization occurred in 58 cases (75.3%) and parenchymal hematoma occurred in 8 cases (10.4%). Distal embolization occurred in 3 cases (3.9%). In 18 of 77 patients (23.4%), distal (ie, intracranial) recanalization was observed after proximal recanalization, obviating the need for distal intervention. Good clinical outcomes were achieved in 32 patients (41.6%). In multivariate analysis, Thrombolysis In Myocardial Ischemia ≥2 recanalization, baseline National Institutes of Health Stroke Scale score, baseline Alberta Stroke Programme Early CT score, and age were significantly associated with good outcome. CONCLUSIONS: Endovascular therapy of tandem occlusions using extracranial internal carotid artery revascularization as the first step is technically feasible, has a high recanalization rate, and results in an acceptable rate of good clinical outcome. Future randomized, prospective studies should clarify the role of this approach.

Protocol adherence and safety of intravenous thrombolysis after telephone consultation with a stroke center.

Intravenous tissue plasminogen activator (tPA) for acute ischemic stroke must be provided in an appropriate setting. The best way to provide thrombolysis in small community hospitals remains uncertain. Medical records were reviewed of tPA treatments at a stroke center between January 2002 and October 2005. The stroke center provides phone consultation for acute stroke to smaller hospitals in the region. Subjects were classified into 3 groups: tPA started at referring hospitals before transfer (treat and transfer group), tPA started at the stroke center after transfer (transfer and treat group), and the control group of patients who presented directly to the stroke center and received tPA (stroke center group). We recorded the patient and treatment characteristics, protocol deviations, symptomatic intracranial hemorrhage (ICH), and in-hospital deaths. There were 133 patients in the treat and transfer group, 35 patients in the transfer and treat group, and 86 patients in the stroke center group. Time from onset to treatment was similar in the treat and transfer and the stroke center groups, but the door-to-needle time was shorter by 12 minutes in the latter (P=.02). Fifty-five protocol deviations occurred in 38% patients in the treat and transfer group, compared with 6% in the stroke center group (P<.001). The most common deviations were related to time window violations and incorrect tPA dosing. Symptomatic ICH occurred in 8.2%, with no significant difference between the groups. Neither community hospital treatment nor protocol deviation was a predictor of symptomatic ICH or in-hospital mortality. Our findings indicate the need for improved protocol adherence for stroke thrombolysis in patients presenting to small community hospitals.

Comparison of safety and clinical and radiographic outcomes in endovascular acute stroke therapy for proximal middle cerebral artery occlusion with intubation and general anesthesia versus the nonintubated state.

BACKGROUND AND PURPOSE: There is considerable heterogeneity in practice patterns between sedation in the intubated state vs nonintubated state during endovascular acute stroke therapy. We sought to compare clinical and radiographic outcomes between these 2 sedation modalities. METHODS: Consecutive patients with acute stroke due to middle cerebral artery-M1 segment occlusion treated with endovascular therapy between January 2006 and July 2009 were identified in our interventional acute stroke database. Level of sedation was determined as intubated (IS) vs nonintubated (NIS) state. Final infarct volumes on follow-up imaging and clinical outcomes at 3 to 6 months were obtained. RESULTS: A total of 126 patients were included (73 [58%] NIS vs 53 [42%] IS). In IS patients, intensive care unit length of stay was longer (6.5 vs 3.2 days, P=0.0008). Intraprocedural complications were lower in NIS patients compared with IS patients (5/73 [6%] vs 8/53 [15%], respectively), but the difference was not significant (P=0.13). In univariate and multivariate analyses, NIS was significantly associated with in-hospital mortality (odds ratio=0.32, P=0.011), good clinical outcome (odds ratio=3.06, P=0.042), and final infarct volume (odds ratio=0.25, P=0.004). CONCLUSIONS: In endovascular acute stroke therapy, treatment of patients in NIS appears to be as safe as treatment in IS and may result in more favorable clinical and radiographic outcomes. Our preliminary observations derived from this retrospective study await confirmation from prospective trials.

Perceptual grouping operates independently of attentional selection: evidence from hemispatial neglect.

To what extent can human observers process visual information that is not currently the focus of attention? We evaluated the extent to which unattended visual information (i.e., that which appears on the neglected side of space in individuals with hemispatial neglect) is perceptually organized and influences the perceptual processing of information on the attended side. To examine this, patients (and matched controls) judged whether successive, complex checkerboard stimuli (targets), presented entirely to their intact side of space, were the same or different. Concurrent with this demanding task, irrelevant distractor elements appeared on the unattended side and either changed or retained their perceptual grouping on successive displays, independently of changes in the ipsilesional task-relevant target. Changes in the grouping of the unattended task-irrelevant distractor elements produced congruency effects on the attended target-change judgment to the same extent in the neglect patients as in the control participants, and this was true even in those patients with severe attentional deficits. These results suggest that some perceptual processes, such as grouping, can operate in the absence of attention.

Endovascular treatment of basilar artery occlusion by manual aspiration thrombectomy.

BACKGROUND AND PURPOSE: Basilar artery occlusion remains one of the most devastating subtypes of stroke. Intravenous and intra-arterial therapy have altered the natural history of this disease; however, clinical results remain poor. Therefore, exploring more aggressive and innovative management is warranted. METHODS: Six consecutive patients presenting with a basilar artery occlusion were treated with the same general algorithm of intra-arterial tissue plasminogen activator and mechanical thrombectomy with the Merci retrieval system. If complete recanalization was not achieved after two passes, manual syringe aspiration through a 4.3F catheter was employed. RESULTS: All interventions utilizing aspiration thrombectomy resulted in recanalization, with five out of six cases displaying TIMI3/TICI3 flow and one patient resulting in complete recanalization of the basilar artery with persistent thrombus in one P2 segment (TIMI2/TICI2B). All patients survived, with five out of six independent in activities of daily living at 3 months (mRS 0-2). CONCLUSIONS: Our small case series indicates that aspiration thrombectomy performed manually through a 4.3F catheter can facilitate recanalization of basilar artery occlusion with acceptable clinical outcomes.

Transient ischemic attack after tissue plasminogen activator: aborted stroke or unnecessary stroke therapy?

BACKGROUND: The frequency with which intravenous thrombolysis for acute ischemic stroke results in normal clinical and radiographic status is currently unknown. METHODS: Patients who received intravenous thrombolysis at community hospitals and a stroke center were retrospectively analyzed for occurrence of normal imaging after tissue plasminogen activator (tPA) treatment. The cases were classified as nonischemic process (stroke mimic), transient ischemic attack (TIA) or ischemic stroke. The occurrence rate and predictors of each condition were sought. RESULTS: Of 254 patients who received tPA, 9 (3.5%) had a nonischemic process, 23 (9.1%) had TIA, and 222 (87%) were diagnosed with ischemic stroke. Nonischemic process patients were younger and were more likely to have received tPA at a community hospital than those with TIA or stroke. TIA was associated with lower pretreatment serum glucose, prevalence of coronary artery disease and stroke severity but not to time to treatment. CONCLUSION: Over 10% of patients who receive tPA for cerebral ischemia do not develop ischemic injury. tPA use for a nonischemic process is infrequent but is associated with community hospital use.

Increased cerebral oxygen metabolism and ischemic stress in subjects with metabolic syndrome-associated risk factors: preliminary observations.

Hypertension, diabetes, obesity, and dyslipidemia are risk factors that characterize metabolic syndrome (MetS), which increases the risk for stroke by 40%. In a preliminary study, our aim was to evaluate cerebrovascular reactivity and oxygen metabolism in subjects free of vascular disease but with one or more of these risk factors. Volunteers (n=15) 59±15 (mean±SD)years of age clear of cerebrovascular disease by magnetic resonance angiography but with one or more risk factors were studied by quantitative positron emission tomography for measure ment of cerebral blood flow, oxygen consumption, oxygen extraction fraction (OEF), and acetazolamide cerebrovascular reactivity. Eight of ten subjects with MetS risk factors had OEF >50%. None of the five without risk factors had OEF >50%. The presence of MetS risk factors was highly correlated with OEF >50% by Fisher's exact test (p<0.007). The increase in OEF was significantly (P<0.001) correlated with cerebral metabolic rate for oxygen. Increased OEF was not associated with compromised acetazolamide cerebrovascular reactivity. Subjects with one or more MetS risk factors are characterized by increased cerebral oxygen consumption and ischemic stress, which may be related to increased risk of cerebrovascular disease and stroke.