bluuebunny/crossref_metadata_2025_split huggingface dataset:
P-024 Stress distribution after intracranial stent by realistic model
Authors: Fujimoto M , Shobayashi Y , Tateshima S , Vinters H , Viñuela F 
Published: July 2012

There is no effective treatment for symptomatic intracranial atherosclerotic stenosis, which has an association with a high rate of recurrent stroke. Percutaneous transluminal angioplasty and stenting (PTAS) has been applied to the intracranial lesion, and only the WingspanTM Stent System (Stryker) was approved by the Food and Drug Administration (FDA) in 2005. However the high incidence of stoke or death (7%–14% at 6 months) and restenosis (25%–32%) have been viewed with suspicion and a randomized trial for intracranial symptomatic severe stenosis (SAMMPRIS Clinical Trial) revealed the superiority of aggressive medical treatments to PTAS. This first-generation intracranial stent can have still room for both procedural and technical improvement. We aimed to explore the cause of stroke complication after stenting in animal model and evaluated the biological response in the Wingspan stent by the fine element method (FEM). Simulation analysis using idealized model showed various stress distribution depended on stent geometries. Although idealized stent analysis has a limitation in its symmetry and uniformity, realistic artery model has been recognized to be essential to prove the correlation with pathobiological response. Some realistic simulation analysis concluded that higher radial stress concentration or non-uniform distribution of wall shear stress could lead to greater neointimal hyperplasia. In this report, we deployed the Wingspan stent at swine ascending pharyngeal artery, and simulated the several stress distribution including radial, circumferential and wall shear stress. We used a realistic arterial model to simulate the clinical situation. As for the radial stress, stress concentration at stent markers and the gradational augmentation of radial stress from proximal to distal were detected. The high wall shear stress gradient at distal stent segment, especially around the stent markers, was also marked. Actually, the excessive intimal hyperplasia was recognized around the distal stent. The radial stress and wall shear stress distribution can have an essential biological implication for intimal hyperplasia. These insights about stress concentration can help us, not only perform the optimal intracranial stenting, but also develop a new endovascular device in future.Competing interestsNone.
P-026 Post-treatment ASPECT area analysis for revascularization effects in the interventional management of stroke (IMS) I/II vs solitaire studies
Authors: Shivashankar R , Tomsick T , Carrozzella J , Investigators I 
Published: July 2012

BackgroundPretreatment baseline ASPECT score is used as a useful predictor of clinical outcome in acute ischemic stroke revascularization; post-treatment ASPECT analysis has not been used to analyze revascularization effects. We hypothesize assessment of post-treatment ASPECT areas may give information on differences between revascularization effects and clinical outcome in competing revascularization studies.PurposeTo examine differences in post-treatment ASPECT regions affected in the Interventional Management of Stroke (IMS) I/II vs Solitaire Studies.Methods24-hr. CT/MR of subjects from the Solitaire Study and from IMS I/II with ICA-T, M1, or M2 occlusion treatment was reviewed. We recorded the degree of revascularization and post-treatment ASPECT areas affected. The cohort was divided into two categories based on site of arterial occlusive lesion (AOL) as Group A (ICA-T or M1 proximal to lenticulostriates) and Group B (M1 or M2 distal to lenticulostriates). The affected ASPECT regions for both groups were then compared for the two studies.Results96 subjects from Solitaire Study (67 Group A, 29 Group B) and 68 from IMSI/II (36 Group A, 32 Group B) with index AOL had complete imaging available for review. Abstract P-0026 figure 1 and 2 displays ASPECT areas for both groups in both studies. Incidence of basal ganglia involvement was similar in both studies, and was frequently found in subjects with AOL beyond the striate arteries. IMS subjects had more peripheral cortex zones affected compared to Solitaire subjects in both groups A and B (p=0.01). Patients in IMSI/II also had more frequent involvement of insular cortex compared to Solitaire subjects in both groups A and B (p<0.001).Abstract P-026 Figure 1Abstract P-026 Figure 2ConclusionIn AOL beyond the origin of lenticulostriate arteries, involvement of basal ganglia may indicate initial deep small vessel occlusion, or early recanalization prior to arteriography. Greater involvement of peripheral cortex and insula in IMS may be an effect of less complete or delayed revascularization, or increased distal emboli (poorer reperfusion). Better preservation of distal tissue following more rapid and complete revascularization with Solitaire is hypothesized.Solitaire Revascularization was not associated with increased basal ganglia ischemia, as might be anticipated due to compression during stent deployment or microembolism during clot retrieval. Other clinical and imaging factors affecting infarct volume will be discussed.Competing interestsNone.
P-027 Review of penumbra system trials: low rate of embolization of previously uninvolved territory of the brain using the penumbra system in acute ischemic stroke treatment: Abstract P-027 Table 1
Authors: Baxter B 
Published: July 2012

Introduction/PurposeEarly and safe revascularization of the primary occlusion correlates with favorable clinical outcome in acute ischemic stroke treatment. One factor in assessing safety of mechanical thrombectomy devices is embolization to a previously uninvolved or new territory (ENT). The Penumbra System is an embolectomy device specifically designed to remove thrombus in acute ischemic stroke through two mechanisms: aspiration and extraction. The purpose of this study is to examine the rate of ENT in the three published Penumbra System trials.Materials and MethodsThree papers reporting results of the Penumbra System trials were analyzed for ENT procedure-related adverse events and total number of cases.ResultsOur analysis of the Penumbra System ENT adverse event rate in the three Penumbra trials is summarized below. In the three studies, which included a total of 303 patients, only one incident of ENT was observed.ConclusionThe unintentional embolization of new territory during mechanical thrombectomy can close collateral flow that is vital to preserving the penumbra. An assessment of the results from three Penumbra trials demonstrates a low rate of ENT of <0.5% using the Penumbra System in treatment for acute ischemic stroke. Aspirating immediately proximal to the thrombus ensures capture of clot at the site of occlusion into a catheter, which may reduce the potential for ENT. Combined with a revascularization rate of 86%, the experience in the three papers shows the ability of the Penumbra System to safely and effectively revascularize the site of primary occlusion.Competing interestsB Baxter: Stryker Neurovascular, EV3, Penumbra, Rapid Medical, Reverse Medical, Codman, Silk Road.Abstract P-027 Table 1Summary of analysis of the penumbra system ENT adverse event rate in the three penumbra trials# of ENT# CasesENT Rate, %Phase 1 study0210Pivotal study11250.8POST study01570Total13030.33
P-030 Impact of point-of-care platelet function testing by VerifyNow on periprocedural antiplatelet therapy in neuroendovascular stenting
Authors: Noorian A , Gupta R , Chester K Wyatt , Faggard J , Gershon R , Nogueira R 
Published: July 2012

BackgroundProper platelet inhibition is essential for prevention of thromboembolic complications in patients undergoing stent placement.ObjectiveThe aim of this study was to analyze the impact of VerifyNow® assay (VNA) on the management of periprocedural antiplatelet therapy in cerebrovascular stenting.Design/MethodsConsecutive patients were retrospectively categorized in three groups: elective (Clopidogrel+aspirin (C+A)≥7 days), urgent (C+A for 12–72 h including clopidogrel bolus),and emergent (no previous C+A, intra-procedural abciximab and postprocedural C+A) stenting groups. Clopidogrel resistance (CR) and hypersensitivity (CH) were defined as <20% and >80% platelet inhibition measured by VNA, respectively.ResultsA total of 72 consecutive patients undergoing cerebrovascular stenting were included in the analysis. Twenty-three patients (age 64±14; 65% male) underwent elective stenting to treat symptomatic atherosclerotic lesions. The rates of CR and CH were 26% and 13%, respectively. Three of the six CR patients were treated with abciximab to achieve platelet inhibition. In one of the patients with CH (96% inhibition), stenting procedure was aborted. There were no hemorrhagic or ischemic complications. Twenty patients (age 60±12; male, 75%) underwent urgent stenting to treat symptomatic atherosclerotic lesions (n=18), medically refractory carotid dissection (n=1), and carotid pseudoaneurysm due to a gunshot wound (n=1). The rates of CR and CH were 60% (12/20) and 5% (1/20), respectively. Nine of the twelve CR patients were treated with abciximab to achieve an average 42%±14% platelet inhibition (range, 22%–52%). There were two hemorrhagic (gastrointestinal bleeding and spontaneous intracranial hemorrhage) with no ischemic events in the CR group. The patient with CH had a spontaneous fatal ICH in the unaffected cerebral hemisphere. Twenty-nine patients (age, 65±15; male, 50%) underwent emergent stenting all presenting with acute ischemic stroke. None of these patients were on chronic outpatient C+A therapy. Two received boluses of Clopidogrel before the procedure. The remaining patients received intra-procedural intravenous abciximab (3–13 mg) to achieve 29%–94% platelet inhibition. There was one intracranial and one systemic hemorrhage with no ischemic events.ConclusionsOur results suggest the applicability of VNA in assuring adequate platelet inhibition. Future studies are needed to manage CR and CH optimally to prevent thrombosis or hemorrhage.Competing interestsA Noorian: None. R Gupta: Concentric Medical, Codman Neurovascular, CoAxia, and Rapid Medical. K Wyatt Chester: None. J Faggard: None. R Gershon: None. R Nogueira: Concentric Medical, ev3 Neurovascular, CoAxia, and Rapid Medical.
P-033 Aneurysm embolization treatment efficiency: comparing the penumbra coil 400TM system to conventional coils
Authors: Patel A , Kamath A , Polykarpou M , Mascitelli J , Patel A , Moyle H 
Published: July 2012

PurposeThe Penumbra Coil 400 System (PC 400) are the newly introduced platinum coils designed specifically to enhance filling efficiency by increasing coil diameter. Reported herein are the results of a comparison study to assess the PC 400's filling advantage in the treatment of cerebral aneurysms as compared to conventional embolic coils (Controls). Particular focus was put on the extent to which the larger diameter affects acute packing density, embolization time and the aneurysm occlusion at 6 months post-treatment.MethodsThis was a single center, retrospective case-review of 111 aneurysm cases treated in 110 patients by the PC 400 (N=16) or Controls (N=95). The aneurysm and procedural characteristics listed below were evaluated. Aneurysm volume and packing density were calculated using AngioCalc (http://www.angiocalc.com), an open source aneurysm calculator endorsed by the manufacturers of the currently available coil systems. Aneurysm occlusion was graded using investigator reported Raymond Scale classification immediately post-procedure, and at 6 (±2) months when patient follow-up was available. The data was then evaluated for statistical significance.ResultsPC 400 (N=16)Controls (N=95)Mean age (yrs)5856 (N=94)Location: ICA/P Comm./A Comm. ACA/MCA/Other (%)50/31.3/12.5/6.2/036.9/21.1/26.3/9.5/6.2Aneurysm volume (mean) (cc)204.3*154.5Ruptured (%)43.857.9# Coils used (mean)3.95.5Coil length (mean) (cm)36.346.8Stent assisted coiling (%)37.528.4Procedure time (mean)(min)46.758.8Packing density (mean) (%)36.2**27.5PC 400 (N=7)Controls (N=44)Follow-up (mean/median) (mos)6.2/7.06.2/6.0Raymond scale-class I occlusion†: approx. 6 months post treatment (%)85.761.4Raymond scale-class I occlusion1Comparison to immediate post-treatment: better/same/worse (%)57.1/42.9/036.4/52.2/11.4*p<0.05, **p<0.005 (non-parametric wilcoxon ranked test).†Classifications from Royet al. Stroke2001;32:1998–2004.ConclusionAneurysm embolization with PC 400 achieved statistically significant greater packing density compared with conventional coils. This was achieved with less procedure time and less total number of coils despite statistically significant greater aneurysm volume. For patient follow-up, the seven PC 400 cases had a greater percentage of Class I Raymond Scale occlusion compared to the controls with available data at 6 months. Our data confirms that when compared to conventional coils, the PC 400 is indeed more efficient in the embolization of cerebral aneurysm, without affecting accessibility or safety.Competing interestsA Patel: Penumbra, Inc. A Kamath: None. M Polykarpou: None. J Mascitelli: None. A Patel: None. H Moyle: None.
P-039 Changes in a neuroendovascular practice after introduction of flow diverters
Authors: Cloft H , Lanzino G , Crobeddu E , Kallmes D 
Published: July 2012

IntroductionFlow diversion represents a major paradigm shift in the treatment of unruptured intracranial aneurysms. The potential impact of this technique on coil utilization and adjunctive techniques such as balloon-assisted and stent-assisted coiling is unknown. In this study, we assessed the effect of introduction of flow diversion devices on coil and adjunctive techniques utilization. We also performed a matched-pair analysis to assess the efficacy of flow diverters compared to traditional endovascular treatment of unruptured paraclinoid aneurysms.MethodsRetrospective review of consecutive patients with unruptured aneurysms treated at our Institution comparing two groups: (Group 1, patients treated in the 2-year interval preceding introduction of the Pipeline Embolization Device (PED) and Group 2 (patients treated during the 2-year interval following introduction in our practice of the PED. For the matched-pair analysis, 21 eligible patients with 22 paraclinoid aneurysms treated with the PED were matched to historical controls with an aneurysm of similar size and location.ResultsMean aneurysm diameter was 8.7±6.3 mm in Group 1 and 8.5±6.1 mm in Group 2 (p=0.79). There were no significant differences in the location of the aneurysms between the two groups suggesting that changes in referral pattern were not responsible for the observed changes in practice patterns. PED therapy was employed in 38 (21.7%) of 175 aneurysms in Group 2. The proportion of stent-assisted procedures was significantly less in Group 2 as compared to Group 1 (6.9% vs 14.7%, respectively, p=0.04), as was the proportion of patients undergoing parent artery sacrifice (0.6% vs 3.9% respectively, p=0.046). The mean and the median number of coils utilized per aneurysm were 5.4±3.6 and 5 (range 1–18) for Group 1 and 3.2±3.2 and 3 (range 0–19) for Group 2 (p≤0.0001). The pair-matched analysis demonstrated a significant difference in the rate of complete occlusion favoring PED at radiological follow-up (77.3% in the PED vs 45.4% in the control group, p=0.03). Complications rates were similar between the two groups.ConclusionFlow diversion represents a disruptive technology. More than one fifth of unruptured aneurysms at our institution were treated with PED after introduction of this technology, resulting in marked decreases in coil and stent utilization. Flow diverters achieve a much higher rate of complete angiographic obliteration when compared to other standard endovascular techniques in the treatment of internal carotid artery aneurysms. In this series, this higher angiographic obliteration rate did not occur at the expenses of an increased rate of complications.Competing interestsH Cloft: Cordis Endovascular. G Lanzino: Educational support from ev3 and Synthes. E Crobeddu: None. D Kallmes: ev3, Micrus, MicroVention, Penumbra, Sequent, NFocus.
P-040 A comparison between particulate and Onyx embolization for devascularization of Juvenile angiofibromas prior to surgical resection
Authors: Gemmete J , Gao M , Pandey A , Chaudhary N , Sullivan S , McKean E , Marentette L 
Published: July 2012

IntroductionJuvenile nasopharyngeal angiofibroma is a locally invasive tumor in adolescent males. Surgical resection is the treatment of choice, but the tumor's extensive vascular involvement necessitates preoperative embolization. In this retrospective cohort, we compare the effectiveness of a novel liquid embolic agent, Onyx (ethylene vinyl alcohol copolymer), to traditional particulate embolic agents in reducing estimated blood loss (EBL) during surgical resection of Juvenile nasopharyngeal angiofibroma.MethodsWe included 46 consecutive resections since 1995 for which preoperative embolization was either particulate (n=39) or Onyx only (n=7), and for which age at operation, date of operation, length of hospital stay, Fisch grade of tumor, resection approach, EBL during resection, and fluids during resection were available. In a subset of 26 resections, OR time was available.ResultsThe mean EBL for the Onyx group was 658.6±858.7 ml and the mean EBL for the particulate group was 1348.6±932.2 ml (one tailed Student t test p=0.043). The mean units packed red blood cells (PRBCs) used in the Onyx group 0.29±0.76 units (p=0.003) and the mean PRBCs used in the particulate cohort was 1.56±2.01. The relationship between embolization type, EBL and embolization type, PRBCs remained significant in the subset of patients with Fisch grade=III (Onyx n=4, particulate n=18, EBL p=0.001 and PRBCs p=0.045), and other Fisch categories did not have enough patients for a statistical analysis. The relationship between embolization type and EBL remained significant after correcting for age at operation (p=0.033). The proportion of resections for which an endoscopic approach was used was significantly higher in the Onyx group than the particulate group (71.4% and 20.5%; p=0.009), and this was also significant in the subset of patients with Fisch grade=III (p=0.040).ConclusionExisting reports suggest that Onyx embolization decreases intraoperative EBL. Our study supports this result and also shows a reduction in units PRBC used intraoperatively. Although further studies are needed, Onyx appears to facilitate a less challenging surgical resection relative to traditional particulate embolization.Competing interestsNone.
P-046 Correlation between recanalization rate and good clinical outcome in acute ischemic stroke, a meta-analysis
Authors: Nourollahzadeh E , Kass-Hout O , Mokin M , Aliotta R , Synder K , Siddiqui A , Levy E , Kass-Hout T 
Published: July 2012

BackgroundEarly recanalization is strongly associated with improved functional outcomes and reduced mortality in acute ischemic stroke (AIS). This is the rationale that stands behind the use of intravenous (IV) or intra-arterial (IA) thrombolytics and the growing list of mechanical thrombectomy devices. There has been multiple small sized studies that have reported this positive association, however, we are lacking a recent review compilation demonstrating this.MethodsData were collected through Medline search. We analyzed all articles published between the years 2002 and 2011 comparing various clinical outcomes including modified Rankin Scale (mRS) at 90 days, symptomatic intracranial hemorrhage, and mortality rate between non-revascularized and revascularized groups in the setting of AIS therapy. Search key words included recanalization, reperfusion, thrombolysis, thrombectomy, modified rankin scale, in combination with ischemic stroke and cerebral ischemia.Results73 studies reporting recanalization rate on 4390 patients were analyzed. Recanalization rate through various intervention approaches were extracted (IV thrombolytic 32%, IA 58%, mechanical thrombectomy 89%, and combined thrombolytic/mechanical 91%). Correlation between clinical outcomes and different revascularization therapies, location of the occlusion and the time from symptom onset to revascularization was only stratified in 68 studies. Patients with successful revascularization defined as Thrombolysis In Myocardial Infarction of 2–3 had a better functional clinical outcome compared to non-revascularized group (Pooled OR 6.01; 95% CI 4.87 to 7.18). Mortality rate was reduced in patients that were revascularized (Pooled OR 0.32; 95% CI 0.18 to 0.41). Symptomatic intracranial hemorrhage rate were reduced for the non-revascularized group, however it was not significant (p=0.31).ConclusionThis meta-analysis further supports the positive correlation between revascularization rate and good functional outcome and reduced mortality rate in AIS.Competing interestsE Nourollahzadeh: None. O Kass-Hout: None. M Mokin: None. R Aliotta: None. K Synder: Toshiba and ev3. A Siddiqui: NINDS 1R01NS064592-01A1, University at Buffalo. Shurtleff, Inc., Concentric Medical, ev3/Covidien Vascular Therapies, GuidePoint Global Consulting, Penumbra. Codman & Shurtleff, Inc., Genentech. Hotspur, Intratech Medical, StimSox, Valor Medical. Abbott Vascular, an Emergency Medicine Conference, Neocure Group LLC, Genentech, American Association of Neurological Surgeons. E Levy: Codman & Shurtleff, Inc, ev3/Covidien Vascular Therapies, Boston Scientific, TheraSyn Sensors, Inc., Medical Ltd., Mynx/Access Closure. Boston Scientific. T Kass-Hout: Genentech.