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.

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.

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.

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.

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.

Lower pretreatment cerebral blood volume affects hemorrhagic risks after intra-arterial revascularization in acute stroke.

OBJECTIVE: Intra-arterial therapies are being used more frequently in patients presenting with acute cerebral occlusions, but they have been limited by the potential for hemorrhage. We sought to determine whether pretreatment computed tomography perfusion parameters might help to identify patients at a higher risk of developing intracranial hemorrhage after intra-arterial stroke revascularization treatment. METHODS: We retrospectively reviewed all patients at the University of Pittsburgh Medical Center and Michigan State University who underwent computed tomography perfusion imaging of the brain before intra-arterial thrombolysis between January 2006 and June 2007. Demographic information, angiographic variables, and types of endovascular interventions were recorded. The mean transit time and cerebral blood volumes were recorded for the ipsilateral and contralateral middle cerebral artery territories. A binary logistic regression model was constructed to determine the independent predictors of developing intracranial hemorrhage. RESULTS: A total of 57 patients (33 from the University of Pittsburgh and 24 from Michigan State University) with a mean age of 66 +/- 13 years and mean National Institutes of Health Stroke Scale scores of 16 +/- 5 were studied. The overall recanalization (Thrombolysis in Myocardial Infarction Trial scale 2 or 3 flow) was 72% for the cohort, and the overall rate of parenchymal hemorrhage was 5 of 57 (9%) patients. The overall hemorrhage rate was 19 of 57 (33%) patients. The only variable found to be predictive of the development of hemorrhage after intervention was reduced pretreatment cerebral blood volume (odds ratio, 0.49; 95% confidence interval, 0.35-0.91; P < 0.022). CONCLUSION: A reduced pretreatment ipsilateral cerebral blood volume value before endovascular revascularization of an acute middle cerebral artery or internal carotid artery occlusion significantly increases the risk of an intracranial hemorrhage.

Neuroimaging in ischemia and infarction.

The authors provide an overview of current clinical neuroimaging techniques for acute ischemic stroke. The pathophysiology of ischemic stroke is briefly reviewed, especially as it pertains to cerebral blood flow. There are three important goals that must be met in the imaging of an acute ischemic stroke: (1) to quantitate the extent of infarction already present; (2) to quantitate the amount of salvageable brain remaining; and (3) to identify the presence of arterial stenosis or occlusion that is both responsible for the stroke and potentially amenable to treatment. Methods of quantifying the degree of infarction, by magnetic resonance imaging or computed tomography, are compared. Techniques for measuring cerebral blood flow, to quantify tissue at risk, are detailed and compared. The quantification of cerebral blood flow is discussed in detail. Methods of visualizing the cerebral circulation are illustrated.

Brain death and withdrawal of support.

The definition of death has evolved to include the concept of brain death. The brainstem is an indispensable central integrative unit for all vital functions. The clinical criteria for brain death consist of the demonstration of the absence of function of the brainstem. Confirmatory testing, which mostly evaluates higher clinical function, is usually not required for the diagnosis of brain death.

Safety, feasibility, and short-term follow-up of drug-eluting stent placement in the intracranial and extracranial circulation.

BACKGROUND AND PURPOSE: The use of bare metal stents to treat symptomatic intracranial stenosis may be associated with significant restenosis rates. The advent of drug-eluting stents (DESs) in the coronary circulation has resulted in a reduction of restenosis rates. We report our technical success rate and short-term restenosis rates after stenting with DESs in the intracranial and extracranial circulation. METHODS: This study was a retrospective review of the period between April 1, 2004, and April 15, 2006, of 59 patients with 62 symptomatic intracranial or extracranial atherosclerotic lesions at 2 medical centers (University of Pittsburgh and Borgess Medical Center). RESULTS: The mean age of our cohort was 61+/-12 years. The location of the 62 lesions was as follows: extracranial vertebral artery 31 (50%), intracranial vertebral artery or basilar artery 18 (29%), extracranial internal carotid artery (ICA) near the petrous bone 5 (8%), and intracranial ICA 8 (13%). There were 2 (3%) periprocedural complications: 1 non-flow-limiting dissection and 1 disabling stroke. Fifty vessels were available for follow-up angiography or computed tomography angiography at a median time of 4.0+/-2 months. A total of 2 of 36 extracranial stents (7%) and 1 of 26 intracranial stents (5%) were found to have restenosis > or = 50% at follow-up. CONCLUSIONS: This report demonstrates that DES delivery in the intracranial and extracranial circulation is technically feasible. A small percentage of patients developed short-term in-stent restenosis. Longer-term follow-up is required in the setting of a prospective study to determine the late restenosis rates for DESs in comparison with bare metal stents.

Reduced pretreatment ipsilateral middle cerebral artery cerebral blood flow is predictive of symptomatic hemorrhage post-intra-arterial thrombolysis in patients with middle cerebral artery occlusion.

BACKGROUND AND PURPOSE: Intracerebral hemorrhage (ICH) can be a devastating complication associated with thrombolytic therapy for acute ischemic stroke. We hypothesized that patients with lower prethrombolysis cerebral blood flow (CBF) were at a higher risk of symptomatic ICH (sICH). METHODS: Twenty-three patients who underwent quantitative CBF assessment with Xenon CT studies for acute stroke before intra-arterial (IA) thrombolysis for a middle cerebral artery (MCA) or internal carotid artery terminus occlusion within 6 hours of symptom onset were studied. Univariate and multivariate analysis were carried out to determine predictors of sICH post-IA thrombolysis. Receiver operating characteristic curves were generated to determine the association between mean ipsilateral CBF and the occurrence of sICH. RESULTS: The mean age of our cohort was 68+/-12 years and a mean National Institutes of Health Stroke Scale (NIHSS) score of 18+/-3. In univariate analysis, patients with higher percent of core infarct, hyperglycemia, and reduced mean ipsilateral CBF were at risk of sICH. In multivariate analysis only mean ipsilateral CBF was associated with higher rates of sICH (odds ratio 1.58; 95% CI, 1.01 to 2.51; P<0.04). The area under the receiver operating characteristic curve was 0.87 (95% CI, 0.76 to 0.97; P<0.005). CONCLUSIONS: Patients with lower pre-IA thrombolysis mean ipsilateral MCA CBF are at significantly higher risk for sICH in the setting of a MCA or carotid terminus occlusion. The threshold identified in this study may be useful for selection of patients with acute MCA occlusions for acute stroke thrombolysis.

A case of conversion disorder presenting as a severe acute stroke.

Conversion disorders often present with dramatic physical presentations suggestive of severe organic disease. We present the case of a young woman who presented to the Emergency Department with a dense left hemiparesis suggestive of a severe acute stroke. Emergent referral to a regional stroke center facilitated rapid medical evaluation, exclusion of organic disease, and confirmation of conversion disorder as the etiology for the symptoms. This report highlights the dramatic clinical presentations that may result from conversion disorders as well as the benefits of rapid medical evaluation by specialty stroke centers.

Multimodal reperfusion therapy for acute ischemic stroke: factors predicting vessel recanalization.

BACKGROUND AND PURPOSE: Endovascular therapies using mechanical and pharmacological modalities for large vessel occlusions in acute stroke are rapidly evolving. Our aim was to determine whether one modality is associated with higher recanalization rates. METHODS: We retrospectively reviewed 168 consecutive patients treated with intra-arterial (IA) therapy for acute ischemic stroke between May 1999 and November 15, 2005. Demographic, clinical, radiographic, angiographic, and procedural notes were reviewed. Recanalization was defined as achieving thrombolysis in myocardial infarction 2 or 3 flow after intervention. A logistic regression model was constructed to determine independent predictors of successful recanalization. RESULTS: A total of 168 patients were reviewed with a mean age of 64+/-13 years and mean National Institutes of Health Stroke Scale score of 17+/-4. Recanalization was achieved in 106 (63%) patients. Independent predictors of recanalization include: the combination of IA thrombolytics and glycoprotein IIb/IIIa inhibitors (odds ratio [OR], 2.9 [95% CI, 1.04 to 6.7]; P<0.048), intracranial stent placement with angioplasty (OR, 4.8 [95% CI, 1.8 to 10.0]; P<0.001), or extracranial stent placement with angioplasty (OR, 4.2 [95% CI, 1.4 to 9.8]; P<0.014). Lesions at the terminus of the internal carotid artery were recalcitrant to revascularization (OR, 0.34 [95% CI, 0.16 to 0.73]; P value 0.006). CONCLUSIONS: Intracranial or extracranial stenting or combination therapy with IA thrombolytics and glycoprotein IIb/IIIa inhibitors in the setting of multimodal therapy is associated with successful recanalization in patients treated with multimodal endovascular reperfusion therapy for acute ischemic stroke.

Emergent stenting of extracranial internal carotid artery occlusion in acute stroke has a high revascularization rate.

BACKGROUND AND PURPOSE: Acute ischemic stroke attributable to extracranial internal carotid artery (ICA) occlusion is frequently associated with severe disability or death. In selected cases, revascularization with carotid artery stenting has been reported, but the safety, recanalization rate, and clinical outcomes in consecutive case series are not known. METHODS: We retrospectively reviewed all of the cases of ICA occlusions that underwent cerebral angiography with the intent to revascularize over a 38-month period. Two groups were identified: (1) patients who presented with an acute clinical presentation within 6 hours of symptom onset (n=15); and (2) patients who presented subacutely with neurologic fluctuations because of the ICA occlusion (n=10). RESULTS: Twenty-five patients with a mean age of 62+/-11 years and median National Institutes of Health Stroke Scale (NIHSS) of 14 were identified. Twenty-three of the 25 patients (92%) were successfully revascularized with carotid artery stenting. Patients in group 1 were younger and more likely to have a tandem occlusion and higher baseline NIHSS when compared with group 2. Patients in group 2 were more likely to show early clinical improvement defined as a reduction of their NIHSS by > or =4 points and a modified Rankin Score of < or =2 at 30-day follow-up. Two clinically insignificant adverse events were noted: 1 asymptomatic hemorrhage and 1 nonflow-limiting dissection. CONCLUSIONS: Endovascular treatment of acute ICA occlusion appears to have a high-recanalization rate and be relatively safe in our cohort of patients with acute ICA occlusion. Future prospective studies are necessary to determine which patients are most likely to benefit from this form of therapy.

Differentiating hemodynamic compromise by the OEF response to acetazolamide in occlusive vascular disease.

Identification of increased stroke risk in a population of symptomatic patients with occlusive vascular disease (OVD) is presently accomplished by measurement of oxygen extraction fraction (OEF) or cerebrovascular reserve (CVR). However, many regions identified by compromised CVR are not identified by OEF. Our aim was to determine whether the response of OEF to acetazolamide, namely, oxygen extraction fraction response (OEFR) would identify those hemispheres in hemodynamic compromise with normal OEF. Nine patients symptomatic with transient ischemic attacks and strokes, and with occlusive vascular disease were studied. Anatomical MRI scans and T2-weighted images were used to identify and grade subcortical white matter infarcts. PET cerebral blood flow (CBF) and OEF were measured after acetazolamide. The relationship between CVR and oxygen extraction fraction response (OEFR) showed that positive OEFR occurred after acetazolamide despite normal baseline OEF values. The two hemispheres with positive OEFR were also associated with severe (> 3 cm) subcortical white matter infarcts. We found that the OEFR was highly correlated with CVR and identified hemispheres that were hemodynamically compromised despite normal baseline OEF.