bluuebunny/crossref_metadata_2025_split huggingface dataset:
O-011 Multimodality management of spetzler-martin grade III arteriovenous malformations
Authors: Pandey P , Steinberg G , Harraher C , Dodd R , Do H , Marks M 
Published: July 2011

IntroductionGrade 3 AVMs are diverse due to variations in size (S), location in eloquent cortex (E) and presence of central venous drainage (V). These variations may have implications for management and outcome which were evaluated in this study.Methods100 patients with grade 3 AVMs were treated from 1984 to 2010. The AVMs were categorized by Spetzler-Martin characteristics as follows: Type 1, S1E1V1, Type 2 S2E1V0, Type 3 S2E0V1 and Type 4 S3E0V0. The occurrence of new neurological deficit, functional status (mRS) at discharge and follow-up, and radiological obliteration were correlated with demographic and morphologic characteristics.Results100 patients (49f, 51 m, age 5–68 years, mean 35.8 years) were evaluated. Size of AVMs were <3 cm (28), 3–6 cm (71) and >6 cm (1); 86 AVMs were in eloquent cortex, and 38 had central drainage. The AVMS were type 1 (28), type 2 (60), type 3 (11) and type 4 (1). Embolization was performed in 77 patients (175 procedures), surgery in 64 patients (74 surgeries), and radiosurgery in 49 patients (44 primary, 5 postoperative). Mortality following the management of these AVMs was 1%. 14 patients (14%) had new neurological deficits, with 5 (5%) disabling (mRS >2), and 9 (9%) non-disabling (mRS <2) events. Patients with type 1 AVM (small AVMs) had the best outcome, with 1/28 (3.6%) having a new neurological deficit as compared to larger AVMs (13/72, 16.7%, p<0.002). Older age (>40 years), size >3 cm, and non-hemorrhagic presentation predicted occurrence of new deficits (p<0.002). Gender, eloquence and venous drainage did not confer any benefit. 89 patients had adequate follow-up to be included in the obliteration analysis. AVM was obliterated in 78 patients (87.6%), 69 of them (78.6%) on angiogram and 9 on MRI/MRA. There was no difference between obliteration rates between different types of AVMs, Size, eloquence and drainage. Age, gender and clinical presentation also did not predict obliteration.ConclusionsMulti-modality management of Grade III AVMs results in a high rate of obliteration which does not appear to be influenced by size, venous drainage or eloquent location. However, the development of new neurologic deficits did correlate with size, while eloquence and venous drainage did not influence this. We propose sub-classifying the grade III AVMs according to their size (<3 cm and >3 cm) to account for treatment risk.
P-010 A Study of the novel 054 Penumbra aspiration device in the ICA and MCA
Authors: Frei D , Bellon R , Huddle D , Dooley G , Gerber J , Turk A , Heck D , Hui F , Joseph G , Jahan R , Miskolczi L , Carpenter J , Grobelny T , Goddard J , Leader B , Bose A , Sit S P 
Published: July 2011

PurposeThe 054 reperfusion catheter is a newly introduced component of the Penumbra System specifically designed to enhance aspiration efficiency by increasing the catheter diameter. The goal of this study was to compare its safety and effectiveness in reducing clot burden in the internal carotid artery (ICA) and the middle cerebral artery (MCA).Methods and MaterialsThis study was a retrospective case review of 74 consecutive patients at 11 international centers with ICA or MCA occlusion who were treated with the Penumbra System. All patients reviewed presented to the hospital within 8 h of symptom onset with a treatable large vessel occlusion (TIMI 0 or 1). The primary endpoint was the rate of successful recanalization as defined by TIMI scores of 2–3.ResultsMean baseline values at enrollment were age 65 years, median NIHSS score 18 (range 2–38), 61% were females, and the median time from symptom onset to arterial puncture was 5 h. After use of the Penumbra System, 91.8% of the treated vessels were revascularized to TIMI 2 or 3. Median time of aspiration was 18 min. Four procedural/device related SAEs were reported in three patients (5.4%). There were a total of 8 (10.8%) symptomatic ICHs reported at 24 h. At 90 days, all cause mortality was 23.0%. Of the 54 patients who either died or reached the 90 days follow-up, 20 (37.0%) had mRS scores of <2. Below are comparisons of the results in the ICA and MCA:ConclusionsThese results suggest that in acute stroke patients with large vessel occlusion, the 054 reperfusion catheter is equi-effective in the reduction of clot burden in the ICA and MCA.Abstract P-010 Table 1All patients (N=74)ICA (N=18)MCA (N=52)TIMI 2–391.8%100%88.5%Procedure/device-related SAEs5.4%5.6%5.7%Death at 90 days23.0%22.2%23.1%
P-014 Venous sinus pulsatility in manometry evaluation of dural sinus narrowing in idiopathic intracranial hypertension
Authors: Lazzaro M , Zaidat O , Darkhabani Z , Fitzsimmons B 
Published: July 2011

IntroductionIdiopathic intracranial hypertension (IIH) remains a poorly understood and therapeutically challenging disease. Enthusiasm has emerged for endovascular therapy with stent reconstruction of dural sinus narrowing, however a complete understanding of the hydrodynamic dysequilibrium is lacking. Few reports have characterized catheter manometry findings and none have addressed the pulsatility of the venous sinuses in IIH.MethodsWe reviewed all cases of patients referred for endovascular evaluation of medically refractory IIH. Patients with venous sinus pulsatility attenuation after stent implantation were identified. Chart and imaging review was performed.ResultsTwo patients were identified with transverse sinus narrowing who underwent stent implantation with demonstrable attenuation of high venous pulsatility. Both cases demonstrated high pressure gradient across the focal narrowing (>30 mm Hg) and >70% stenosis. Mid-term follow-up revealed persistent clinical improvement.ConclusionsWe report the finding of high venous sinus pulsatility attenuation after stent implantation for dural sinus narrowing and propose the hypothesis that this finding is a marker of advanced dural sinus incompetence. This characteristic may be useful in identifying patients who would benefit from endovascular stent remodeling.
P-015 Initial experience with a coaxial dual-lumen balloon catheter for wide-neck aneurysm coil embolization
Authors: Lazzaro M , Zaidat O , Badruddin A , Fitzsimmons B 
Published: July 2011

IntroductionTechniques for coil-embolization of wide-neck cerebral aneurysms include the use of stents and temporary occlusion with compliant non-detachable balloons to achieve safe and densely packed coil positioning. We describe the use of a new balloon device for wide-neck aneurysm treatment.MethodsA single institution neuroendovascular device inventory was accessed to identify cases in which the Ascent balloon (Micrus Endovascular, San Jose, California, USA) was used for aneurysm coil embolization. Clinical, demographic, and angiographic data were obtained through chart review.ResultsSix cerebral aneurysm cases were treated using the Ascent balloon during the first 8-month period that the new device was available at our institution. Two of the patients presented with ruptured aneurysms. All aneurysms were large (maximum diameter 7 mm or greater) with an average neck length of 6.1 mm. Complete occlusion with coil embolization (Raymond class I) was achieved in all cases. The Ascent balloon was successfully positioned across the neck of the aneurysm in five patients, while delivery to the aneurysm neck was unsuccessful due to vessel tortuosity in one patient.ConclusionsThis initial experience demonstrates the feasibility, initial outcomes, and short-term follow-up results of a coaxial dual-lumen design balloon catheter used as an assistive device in coil embolization of wide-neck cerebral aneurysms. This new device contributes to the growing number of options for treatment of complex cerebral aneurysms.
P-032 Vascular reconstruction devices shrink small cerebral aneurysms
Authors: Nyberg E , Larson T 
Published: July 2011

Endovascular treatment of intracranial aneurysms (IAs) often includes the deployment of a vascular reconstruction device (VRD), particularly if the aneurysm has a wide neck or unfavorable dome to neck ratio, to prevent coil herniation and to facilitate increased packing density. However other benefits may be hemodynamic and physiologic, that is, through flow diversion, reduced wall shear stress (WSS), and the provision of a scaffolding to support endotheliazation over the aneurysm neck. Hemodynamic simulations using computational flow dynamics suggest that the effect of flow diversion exerted by the Enterprise VRD decreases flow velocity in the aneurysm, increases stasis and decreases WSS, however to our knowledge clinical examples have not been published. We present four cases of staged, elective treatment of small saccular intracranial aneurysms in which placement of a single Enterprise VRD or Wingspan stent alone prompted beneficial aneurysm remodeling such that by the time of the planned coiling several weeks later these aneurysms had substantially decreased in size and it was felt that coil embolization was no longer feasible. We surmise that the VRDs in our series improved hemodynamic conditions enabling aneurysm shrinkage. This may have been accomplished in part by flow diversion by the device struts as simulations have predicted. However, another mechanism of remodeling may involve changing the geometry of the aneurysm and parent vessel. Increased WSS and WSS gradients are often found at vascular branch points or curvatures, therefore straightening of the parent vessel may be beneficial in these cases. All patients in our series demonstrated some degree of vessel straightening. Protrusion of device struts into the dome may also play a beneficial role. In summary, benefits of VRDs not directly related to coil packing may include flow diversion allowing for thrombotic retraction of the dome as well as decreased WSS and WSS gradients due to vessel straightening. Thus staging treatment in this manner may allow the aneurysm to shrink in some patients, thereby avoiding the risk of coil embolization. The long term prognosis of these tiny aneurysm remnants is unknown and these patients clearly need to be followed. Furthermore, whatever hemodynamic effects single VRDs may exert are unlikely to be effective in larger aneurysms, perhaps >3 mm.Abstract P-032 Figure 1Likely atherosclerotic aneurysm of the distal left vertebral artery (figure 1A and B) was initially treated with an Enterprise VRD. Short term follow up (figure 1C and D) demonstrates marked decrease in aneurysm size and partial vessel straightening.
E-003 Localization of spinal dural arteriovenous fistula: diagnosis and implications
Authors: Yen P , Maloney W , Schmidt M , Vandorpe R , Shankar J 
Published: July 2011

PurposeSpinal Dural Arteriovenous Fistula (SDAVF) is a rare acquired lesion that can impair spinal cord function. Early diagnosis is very important since the symptoms can be reversed if treated prior to irreversible cord ischemia or infarction. Characteristic features of the spinal MRI includes multi-leveled T2 hyperintensity in the spinal cord signifying cord edema and prominent flow voids in the extramedullary and intradural space from venous congestion. These prominent flow voids are commonly mistaken for primary vascular malformation. It is important to note that the flow voids are the consequence of venous congestion and not the site of fistulous shunting. The understanding of this disease process is pertinent in safe treatment planning. We aim to show that neither the distribution of flow voids nor the intramedullary findings are related to the location of the fistula.Materials and MethodsWe retrospectively analyzed cases of SDAVFs in the last 2 years. All patients underwent clinical examination, MRI of the whole spine and spinal digital subtraction angiogram (DSA). We compared the level of the fistula based on the clinical presentation and MR images with that of the DSA findings.ResultsThere were a total of 7 cases of SDAVFs. All patients presented with progressive myelopathy. Initial MRI showed extensive T2 hyperintensity in the spinal cord and flow voids in the extramedullary, intradural space. Subsequent DSA identified the location of the fistula ranging from the cranio-cervical junction to the sacral level. Clinical presentation and MRI findings were not predictive of location of fistula found on spinal DSA. In one case, the patient's time resolved MR angiography was able to localize the fistula which was later confirmed on spinal DSA.DiscussionSDAVFs represent an abnormal connection between the segmental dural arterial supply and the vein, which eventually drain into the perimedullary vein. This results in retrograde venous congestion in the spinal cord. This usually manifest as dilated perimedullary veins on MRI and T2 hyperintensity in spinal cord secondary to congestion and edema and clinically as progressive myelopathy. Since the spinal perimedullary venous system is an integrated system, congestion secondary to SDAVF at any spinal level can result in venous congestion of the spinal cord. Hence, the venous congestion is the consequence and not the cause and result in the characteristic clinical and MRI presentations. Only spinal DSA accurately demonstrate the fistula location. Standard contrast-enhanced MR angiography in combination with MRI has been shown recently to increase accuracy of fistula localization.SummaryClinical presentation and MRI findings are very useful in pointing toward the diagnosis of SDAVF but do not give any indication about of the location of fistula. Location of fistula can be shown only on spinal DSA or in some cases time resolved MR angiography. This understanding is very important in the planning of safe treatment.
O-007 Decreases in temperature and relative humidity leading to an increased incidence of ischemic stroke
Authors: Petrov D , Hidalgo A , Gandhi C , Prestigiacomo C 
Published: July 2011

IntroductionThe influence of meteorological variables on the incidence of ischemic stroke has been described in neurological literature. The link between weather conditions and overall morbidity and mortality has been established, with an increase during the winter months and during periods of extreme heat. Conversely, certain studies have established a link between lower temperatures and ischemic events. The equivocal data demands further inquiry into the connection between weather variable and ischemic events. Since certain studies on the association of stroke and meteorological variable are based in areas of very specific, extreme weather patterns the results may not be generalizable to more temperate climates. We aim to investigate the role of meteorological variables on the rate of ischemic events in a representative east coast inner city population.MethodsA database of stroke patients treated at University Hospital in Newark, NJ, from 7.2009 to 7.2010 was used. Standardized data collection were utilized, including demographic, relevant medical history, medications, laboratory data on admission, vitals on admission, and disease course. Consecutive days with stroke admissions as well as singleton days with multiple stroke admissions were classified as clusters. Data from the national weather database data from the event dates recorded at the Newark airport weather station located 5.4 miles from University Hospital as well as the weather underground database (wunderground.com), collected 1.1 miles away from University Hospital was compared on ischemic event vs no ischemic event days as well as cluster vs non-cluster days. Data were analyzed using ANOVA to compare weather parameter as follows: (1) dates with ischemic events to days without ischemic event; (2) cluster vs non-cluster days.ResultsDuring the study period, 297 ischemic events were treated at University Hospital, 267 with ischemic stroke and 30 with TIA. The variation of monthly admission rates was insignificant. Analysis of the data revealed a statistically significant correlation between a decrease in max temperature, min temperature, average temp, dew point, and wet bulb temperature and an increased incidence of stroke. Likewise, a statistically significant decrease in those variables was also associated with increased clustering of ischemic events (p<0.01).ConclusionLower temperatures as well decrease in relative humidity (measured by wet bulb temperature and dew point) are associated with an increased hospital admission rate for ischemic stroke and TIA.
E-014 The “sandwich” technique for interventional management of AIS
Authors: Crudup J , Hartley B , Baxter B 
Published: July 2011

IntroductionDevices currently used in the endovascular treatment of acute ischemic stroke employ either aspiration or mechanical thrombectomy separately but not in combination. Recent advancements in catheter design have made the delivery of coaxial catheters to the intracranial occlusive lesion standard practice. At our institution, we have found the use of Concentrics Distal Access Catheter (DAC) adjunctively with a thrombectomy device to be effective in increasing catheter stability and enhancing clot retrieval. Further, we have found a novel use of the DAC during mechanical thrombectomy. With the DAC tip being placed at or within the proximal end of the clot and the retriever embedded distally in the clot, we employ aspiration through the DAC during the retrieval process. The clot is “sandwiched” between the combined forces of aspiration and mechanical extraction. DAC carries an approval for aspiration in Europe and Canada, but in the USA this is an off label use of the catheter. The aim of this “sandwich” technique is to enhance the thrombectomy procedure by decreasing the number of passes required and shortening the time to revascularization.MethodsA retrospective review of mechanical thrombectomy cases performed at our institution after introduction of the DAC was conducted. Cases were reviewed from November 24, 2008 to April 1, 2011. From these cases, 25 were found in which the “sandwich” technique was utilized. The imaging and procedural reports were reviewed to insure that an appropriate and consistent “sandwich” technique was performed. Outcome measures analyzed were the rate of successful revascularization (using the TICI scoring system), 90-day Modified Rankin Scale (mRS) score, and the 90-day mortality rate.Results25 patients were identified (mean age, 65 years; gender, males 48%, females 52%; mean baseline NIHSS, 18). Successful revascularization (defined as achieving a TICI score of 2a, 2b or 3) was achieved in 20/25 (80%) patients. The rate of good outcomes (defined as a 90-day mRS 0–2) was achieved in 11/25 (44%). The 90-day mortality rate was 32% (8/25).ConclusionsThe “sandwich” technique yields favorable successful revascularization rates and good clinical outcomes as compared to current endovascular therapies reported in the literature for acute ischemic stroke treatment. Although not initially intended for this purpose, we feel that using the DAC to adjunctively aspirate during the mechanical thrombectomy procedure to be helpful. Further study in a larger patient population to explore whether this technique offers benefit over “traditional” thrombectomy is required.
Impacts of the Lowest Model Level Height on the Performance of Planetary Boundary Layer Parameterizations
Authors: Shin Hyeyum Hailey , Hong Song-You , Dudhia Jimy 
Published: July 2011

The lowest model level height z1 is important in atmospheric numerical models, since surface layer similarity is applied to the height in most of the models. This indicates an implicit assumption that z1 is within the surface layer. In this study, impacts of z1 on the performance of planetary boundary layer (PBL) parameterizations are investigated. Three conceptually different schemes in the Weather Research and Forecasting (WRF) model are tested for one complete diurnal cycle: the nonlocal, first-order Yonsei University (YSU) and Asymmetric Convective Model version 2 (ACM2) schemes and the local, 1.5-order Mellor–Yamada–Janjić (MYJ) scheme. Surface variables are sensitive to z1 in daytime when z1 is below 12 m, even though the height is within the surface layer. Meanwhile during nighttime, the variables are systematically altered as z1 becomes shallower from 40 m. PBL structures show the sensitivity in the similar manner, but weaker. The order of sensitivity among the three schemes is YSU, ACM2, and MYJ. The significant sensitivity of the YSU parameterization comes from the PBL height calculation. This is considerably alleviated by excluding the thermal excess term in determining the PBL height when z1 is within the surface layer. The factor that specifies the ratio of nonlocal transport to total mixing is critical to the sensitivity of the ACM2 scheme. The MYJ scheme has no systematic sensitivity, since it is a local scheme. It is also noted that a numerical instability appears accompanying the unrealistic PBL structures when the grid spacing in the surface layer suddenly jumps.
Animal escapology II: escape trajectory case studies
Authors: Domenici Paolo , Blagburn Jonathan M. , Bacon Jonathan P. 
Published: July 2011

SummaryEscape trajectories (ETs; measured as the angle relative to the direction of the threat) have been studied in many taxa using a variety of methodologies and definitions. Here, we provide a review of methodological issues followed by a survey of ET studies across animal taxa, including insects, crustaceans, molluscs, lizards, fish, amphibians, birds and mammals. Variability in ETs is examined in terms of ecological significance and morpho-physiological constraints. The survey shows that certain escape strategies (single ETs and highly variable ETs within a limited angular sector) are found in most taxa reviewed here, suggesting that at least some of these ET distributions are the result of convergent evolution. High variability in ETs is found to be associated with multiple preferred trajectories in species from all taxa, and is suggested to provide unpredictability in the escape response. Random ETs are relatively rare and may be related to constraints in the manoeuvrability of the prey. Similarly, reports of the effect of refuges in the immediate environment are relatively uncommon, and mainly confined to lizards and mammals. This may be related to the fact that work on ETs carried out in laboratory settings has rarely provided shelters. Although there are a relatively large number of examples in the literature that suggest trends in the distribution of ETs, our understanding of animal escape strategies would benefit from a standardization of the analytical approach in the study of ETs, using circular statistics and related tests, in addition to the generation of large data sets.