Showing papers by "David Fiorella published in 2013"

Pipeline for uncoilable or failed aneurysms: results from a multicenter clinical trial.

Abstract: The Pipeline for Uncoilable or Failed Aneurysms study demonstrated a high rate (78 of 108, 73.6%) of complete occlusion of large and giant wide-necked aneurysms of the internal carotid artery and a reasonably low rate of major safety events (6 of 107, 5.6% rate of major stroke or neurologic death).

Initial clinical experience with the ADAPT technique: a direct aspiration first pass technique for stroke thrombectomy

Abstract: Background The development of new revascularization devices has improved recanalization rates and time but not clinical outcomes. We report our initial results with a new technique utilizing a direct aspiration first pass technique with a large bore aspiration catheter as the primary method for vessel recanalization. Methods A retrospective evaluation of a prospectively captured database of 37 patients at six institutions was performed on patients where the ADAPT technique was utilized. The data represent the initial experience with this technique. Results The ADAPT technique alone was successful in 28 of 37 (75%) cases although six cases had large downstream emboli that required additional aspiration. Nine cases required the additional use of a stent retriever and one case required the addition of a Penumbra aspiration separator to achieve recanalization. The average time from groin puncture to at least Thrombolysis in Cerebral Ischemia (TICI) 2b recanalization was 28.1 min, and all cases were successfully revascularized. TICI 3 recanalization was achieved 65% of the time. On average, patients presented with an admitting National Institutes of Health Stroke Scale (NIHSS) score of 16.3 and improved to an NIHSS score of 4.2 by the time of hospital discharge. There was one procedural complication. Discussion This initial experience highlights the fact that the importance of the technique with which new stroke thrombectomy devices are used may be as crucial as the device itself. The ADAPT technique is a simple and effective approach to acute ischemic stroke thrombectomy. Utilizing the latest generation of large bore aspiration catheters in this fashion has allowed us to achieve excellent clinical and angiographic outcomes.

Mechanisms of stroke after intracranial angioplasty and stenting in the SAMMPRIS trial.

Abstract: Background Enrollment in the Stenting and Aggressive Medical Management for the Prevention of stroke in Intracranial Stenosis (SAMMPRIS) trial was halted owing to higher than expected 30-day stroke rates in the stenting arm. Improvement in peri-procedural stroke rates from angioplasty and stenting for intracranial atherosclerotic disease (ICAD) requires an understanding of the mechanisms of these events.

A multicenter study of stent-assisted coiling of cerebral aneurysms with a Y configuration.

Abstract: BACKGROUND: Stent-assisted coiling with 2 stents in a Y configuration is a technique for coiling complex wide-neck bifurcation aneurysms. OBJECTIVE: We sought to provide long-term clinical and angiographic outcomes with Y-stent coiling, which are not currently established. METHODS: Seven centers provided deidentified, retrospective data on all consecutive patients who underwent stent-assisted coiling for an intracranial aneurysm with a Y-stent configuration. RESULTS: Forty-five patients underwent treatment by Y-stent coiling. Their mean age was 57.9 years. Most aneurysms were basilar apex (87%), and 89% of aneurysms were unruptured. Mean size was 9.9 mm. Most aneurysms were treated with 1 open-cell and 1 closed-cell stent (51%), with 29% treated with open-open stents and 16% treated with 2 closed-cell stents. Initial aneurysm occlusion was excellent (84% in Raymond grade I or II). Procedural complications occurred in 11% of patients. Mean clinical follow-up was 7.8 months, and 93% of patients had a modified Rankin Scale score of 0 to 2 at last follow-up. Mean angiographic follow-up was 9.8 months, and 92% of patients had Raymond grade I or II occlusion on follow-up imaging. Of those patients with initial Raymond grade III occlusion and follow-up imaging, all but 1 patient progressed to a better occlusion grade (83%; P < .05). Three aneurysms required retreatment because of recanalization (10%). There was no difference in initial or follow-up angiographic occlusion, clinical outcomes, incidence of aneurysm retreatment, or in-stent stenosis among open-open, open-closed, or closed-closed stent groups. CONCLUSION: In a large multicenter series of Y-stent coiling for bifurcation aneurysms, there were low complication rates and excellent clinical and angiographic outcomes.

Physical Factors Effecting Cerebral Aneurysm Pathophysiology

Abstract: Many factors that are either blood-, wall-, or hemodynamics-borne have been associated with the initiation, growth, and rupture of intracranial aneurysms. The distribution of cerebral aneurysms around the bifurcations of the circle of Willis has provided the impetus for numerous studies trying to link hemodynamic factors (flow impingement, pressure, and/or wall shear stress) to aneurysm pathophysiology. The focus of this review is to provide a broad overview of such hemodynamic associations as well as the subsumed aspects of vascular anatomy and wall structure. Hemodynamic factors seem to be correlated to the distribution of aneurysms on the intracranial arterial tree and complex, slow flow patterns seem to be associated with aneurysm growth and rupture. However, both the prevalence of aneurysms in the general population and the incidence of ruptures in the aneurysm population are extremely low. This suggests that hemodynamic factors and purely mechanical explanations by themselves may serve as necessary, but never as necessary and sufficient conditions of this disease’s causation. The ultimate cause is not yet known, but it is likely an additive or multiplicative effect of a handful of biochemical and biomechanical factors.

The FDA approval process for medical devices: an inherently flawed system or a valuable pathway for innovation?

Abstract: Medical devices, developed through physician and industry partnerships, have helped to revolutionize the treatment of disease spanning most medical disciplines. This includes such entities as deep brain stimulation implants for Parkinson's disease, knee replacements for osteoarthritis, coil embolization technologies for intracranial aneurysms and implantable cardiac defibrillators for life-threatening arrhythmias. These remarkable products have undeniably led to increased patient longevity and improved quality of life. Such marvels of modern medicine, however, do not come without cost, to either the consumer or the manufacturer. Recent estimates suggest that the annual expenditures on medical devices in the USA approximates $95–150 billion, which represents almost one-half to three-quarters of the $200 billion spent on such devices across the world and about 6% of our total national health expenditures.1 ,2 Development of new technologies requires considerable investment from companies in terms of research and development costs, manufacturing and marketing, as well as a rigorous approval process through the Food and Drug Administration (FDA). All-in-all, the price of innovation is monumental for those invested in advancing medicine through cutting edge technologies. Recently, there has been a push among lobbyists representing device manufacturers to streamline the lengthy FDA approval process,3 arguing that the USA will lose its ability to compete globally due to the excessive costs and delays in obtaining FDA approval. However, in direct contrast to any effort to ‘streamline’ the approval process, the oversight of device innovation and the approval process has been criticized recently due to several notable device ‘failures’ that have been linked to patient harm. These devices were approved for use through FDA humanitarian device exemption (HDE) or 510(k) processes, which do not require randomized controlled trial evidence demonstrating safety and effectiveness prior to …

Impact of operator and site experience on outcomes after angioplasty and stenting in the SAMMPRIS trial

Abstract: Background and purpose To investigate the relationship between physician and site experience and the risk of 30 day hemorrhagic and ischemic strokes in the stenting arm of the Stenting and Aggressive Medical Management for the Prevention of Recurrent Ischemic Stroke (SAMMPRIS) trial. Methods Study records and an investigator survey were examined for physician and site related factors, including: number of Wingspan and aneurysm stents submitted for credentialing, number of study procedures performed in SAMMPRIS, years in practice after training, primary specialty, and site enrollment. Bivariate and multivariate analyses were performed to determine if these factors were associated with the 30 day rate of cerebrovascular events after angioplasty and stenting. Results 213 patients underwent angioplasty alone (n=5) or angioplasty and stenting (n=208) with study devices by 63 interventionists at 48 sites. For credentialing, the median number of Wingspan and similar aneurysm stent cases submitted by study interventionists were 10 and 6, respectively. Interventionists with higher numbers (>10) of Wingspan cases submitted for credentialing tended to have higher rates of 30 day events (19.0% vs 9.9%) than those with 12 patients). Conclusions Interventionists credentialed with less Wingspan experience were not responsible for the high rate of periprocedural stroke in SAMMPRIS. Hemorrhagic stroke may be related to low enrollment in the trial but not previous Wingspan experience.

Endovascular Treatment of Complex Aneurysms at the Vertebrobasilar Junction With Flow-Diverting Stents: Initial Experience

Abstract: Background Large or giant complex vertebrobasilar junction aneurysms have a dismal natural history and are often challenging to treat with standard endovascular or neurosurgical techniques. Objective To report initial experience with endovascular treatment of these aneurysms using flow-diverting stents (FDS). Methods Ten patients with FDS treatment of complex vertebrobasilar junction aneurysms were collected from 4 large cerebrovascular centers. Clinical/angiographic presentation and outcome were retrospectively analyzed. Results Of 10 aneurysms, 7 presented with brainstem compression, 2 with ischemia, and 1 with subarachnoid hemorrhage, and 3 were recurrent after stent-assisted treatments. Eight were giant. Morphology was fusiform in 5, fusiform dissecting in 1, and multilobulated saccular in 4. Six were partially thrombosed. In addition to FDS (mean number of devices, 3.9; range, 1-9), contralateral vertebral artery sacrifice and adjunctive coiling were performed in 9 and 5 of the 10 patients, respectively. At follow-up, 5 of 10 were completely occluded, 4 showed minimal residual filling, and 1 was retreated with an additional FDS. Postinterventionally, worsening mass effect and ischemic complications were seen in 2 and 4 of 10, respectively. Clinical outcome was good in 6 (modified Rankin Scale score, 0-2). Four fatalities were related to sequelae of subarachnoid hemorrhage, late FDS thrombosis, progressive mass effect, and delayed intracranial hemorrhage. Conclusion FDS may be used to treat complex vertebrobasilar junction aneurysms with overall good angiographic outcome. A combined reconstructive/deconstructive approach appears useful to avoid endoleaks. FDS strategies, like other endovascular and neurosurgical approaches to these lesions, are associated with significant risk and therefore should be reserved for those cases in which alternative approaches either are deemed unsafe or are likely to be ineffective. Abbreviations FDS, flow-diverting stentPED, Pipeline Embolization DeviceSAH, subarachnoid hemorrhageVA, vertebral arteryVBJ, vertebrobasilar junction.

Mechanical thrombectomy as first-line treatment for venous sinus thrombosis: technical considerations and preliminary results using the AngioJet device

Abstract: Background Cerebral venous sinus thrombosis (CVT) is an uncommon cause of stroke that is usually treated medically with intravenous heparin therapy followed by long-term anticoagulation therapy. A series of patients with CVT who underwent rheolytic thrombectomy with the AngioJet as a first-line adjunctive treatment in addition to standard anticoagulation therapy is presented. Methods Prospectively maintained endovascular databases at two institutions were retrospectively reviewed. The available clinical and imaging data were compiled at each institution and combined for analysis. Results Over 18 months, 13 patients (seven women and six men; age range 17–73 years, median age 45 years) with CVT were treated with rheolytic thrombectomy. Immediate (partial or complete) recanalization of the thrombosed intracranial sinuses was achieved in all patients. At a median radiographic follow-up of 7 months there was continued patency of all recanalized sinuses. Clinical follow-up was available on nine patients: modified Rankin score of 0 in four patients, 1 in three patients and 6 in two patients. Conclusion This series demonstrates the feasibility of performing mechanical thrombectomy as a first-line treatment for acute CVT. This technique facilitates the prompt restoration of intracranial venous outflow, which may result in rapid neurological and symptomatic improvement.

Estimating the proportion of intracranial aneurysms likely to be amenable to treatment with the pipeline embolization device

Abstract: Objective A study was undertaken to estimate the fraction of intracranial aneurysms that might be amenable to treatment with the pipeline embolization device (PED), a current flow diverter device, and to determine the types of aneurysms that are probably not amenable to treatment with this device. Methods A retrospective analysis of 200 consecutive intracranial aneurysms as seen on three-dimensional rotational angiography images was conducted. Based on aneurysm and parent artery morphology, four independent observers experienced in the use of the PED judged the likelihood that a given aneurysm could theoretically be treated with one or more PED using a 5-point scale: grades 1 and 2 indicated amenability to treatment with multiple devices; grade 3 indicated amenability to treatment with one device; and grades 4 and 5 indicated the aneurysm would not be amenable to treatment with the PED. Aneurysms were analyzed on the basis of anatomical factors only. Rupture status was not considered. Interobserver agreement was determined. Results 94 of 200 aneurysms (47%) were judged to be likely to be amenable to treatment with the PED; 50 cases (25%) were judged to be amenable to the use of multiple overlapping devices while, in 44 cases (22%), coverage with a single device was preferred. There was a significant relationship between the location of the aneurysm and the grade of the aneurysm (p Conclusion On the basis of anatomical configuration, nearly half of the aneurysms in this study were likely to be amenable to treatment with the PED.

Balloon-assisted guide catheter positioning to overcome extreme cervical carotid tortuosity: technique and case experience

Abstract: Background and significance We describe a method by which to efficiently and atraumatically achieve distal positioning of a flexible guiding catheter beyond extreme cervical tortuosity using a hypercompliant temporary occlusion balloon. Methods A retrospective review of a prospective neuroendovascular database was used to identify cases in which a hypercompliant balloon catheter (Hyperform or Hyperglide, ev3/Covidien, Irvine, California, USA; Scepter or Scepter XC, Alisa Viejo, California, USA) was used to achieve distal positioning of a flexible guiding catheter (Navion, ev3/Covidien, Irvine, California, USA; Neuron, Penumbra Inc, Alameda, California, USA). After achieving a stable guiding sheath position within the proximal cervical carotid artery, a hypercompliant balloon catheter was manipulated beyond the tortuous cervical internal carotid segment into the distal carotid artery. The balloon was then inflated to anchor it distally within an intracranial (cavernous or petrous) segment of the internal carotid artery. The guiding catheter was then advanced beyond the tortuous cervical segment, over the balloon catheter, as gentle counter traction was applied to the balloon. Results Balloon-assisted guiding catheter placement was used to perform endovascular treatments of 12 anterior circulation aneurysms. One patient underwent coiling alone. Five patients underwent balloon-assisted coiling. One patient underwent balloon and stent assisted coil embolization. Four patients with five carotid aneurysms (one with bilateral carotid aneurysms) underwent vascular reconstruction with the pipeline embolization device. All patients had severe tortuosity of the extracranial carotid system. Three patients had findings consistent with cervical carotid fibromuscular dysplasia. The technique was successful each time it was attempted. No parent artery dissections or catheter induced vasospam were noted in any case. Discussion Hypercompliant balloon catheters can be reliably used to facilitate safe and rapid distal positioning of flexible guiding catheters beyond severe cervical tortuosity.

Cardiac simulation device

Abstract: The present invention describes a device and system for simulating normal and disease state cardiac functioning, including an anatomically accurate left cardiac simulator for training and medical device testing. The system and device uses pneumatically pressurized chambers to generate ventricle and atrium contractions. In conjunction with the interaction of synthetic mitral and aortic valves, the system is designed to generate pumping action that produces accurate volume fractions and pressure gradients of pulsatile flow, 'duplicating that of a human heart. Through the use of a remote handheld electronic controller and manual adjustments from a main control panel, the air pressure level, fluidic pressure, and heart rate is controlled to induce contractions that simulate a wide variety of heart conditions ranging from normal heart function to severely diseased or injured heart conditions.

Report of two cases of a rare cause of subarachnoid hemorrhage including unusual presentation and an emerging and effective treatment option

Abstract: Purpose To report two cases of a rare cause of subarachnoid hemorrhage (SAH), including unusual presentation and an emerging and effective treatment option. Case reports Ruptured basilar perforator artery aneurysm is a rare cause of SAH. Catheter angiography in the immediate post hemorrhage period may be unrevealing. We report two cases of ruptured basilar pontine perforator aneurysms. In one of these cases the perforator aneurysm was not apparent on the initial or the 1 week follow-up angiograms. Both patients returned for follow-up angiography 2 months later by which time aneurysmal filling and conspicuity had increased. Both patients were treated solely with two overlapping Neuroform stents. Follow-up angiograms demonstrated complete resolution of the aneurysms in both patients. Conclusions Rupture of aneurysms arising from basilar artery perforators is a rare cause of SAH and attention to this area should be part of an interventionist's search pattern. Aneurysms in this area may not be apparent in the immediate post rupture setting and delayed post hemorrhage angiography has a role in detecting this entity. Stent monotherapy may be effective in treating these lesions.

The tribulations of stroke trials.

Abstract: In February the New England Journal of Medicine published the long-awaited results of three prospective stroke trials. The Interventional Management of Stroke III (IMS III) trial, the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) trial and the SYNTHESIS Expansion trial all concluded that endovascular therapy (EVT) was not superior to medical management in the treatment of acute stroke.1–3 A critical appraisal of these trials, however, raises serious questions as to their applicability to the contemporary treatment of acute ischemic stroke. In evaluating the results, it is of paramount importance to keep two seemingly obvious fundamental concepts in mind. First, endovascular techniques are not designed to treat all acute ischemic stroke; they are specifically designed to address stroke secondary to large vessel occlusion (LVO). Any clinical trial testing the efficacy of a procedure must be meticulously designed to exclude patients who do not have the index disease process—in this case LVO. Any trial of EVT which includes a significant percentage of patients without the index disease will have little or no capacity to demonstrate a treatment effect. The IMS III and SYNTHESIS Expansion trials both fail in this regard. Second, in order to evaluate a treatment paradigm within in a clinical trial—in this case EVT—it is a prerequisite that the allocated treatments are actually performed in those subjects randomized to the treatment arm and that the technical success rates achieved by the devices and operators are acceptable within the context of current practice. The IMS III and MR RESCUE trials both fail in this regard. Unfortunately, these basic criteria for clinical trials are sometimes lost in the overriding momentum to report a final definitive conclusion. IMS III sought to compare the efficacy of combined intravenous tissue plasminogen activator (tPA) administration plus ‘protocol-approved’ EVT with that of …

Randomized clinical trials: the double edged sword

Abstract: > “Evidence based medicine has contributed to the development of a rigid hierarchy of research design that underestimates the limitations of randomized controlled trials”1 > J Concato In May 2013, the Data Safety Monitoring Board of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) halted enrollment due to excess morbidity in the interventional group. This result was not surprising to the medical community, as prior editorials attest.2 Until complete trial data are available, it is impossible to determine why interventional treatment was deemed inferior to medical management. However, the trial had major inherent limitations that portended failure from the outset. Brain arteriovenous malformations (AVMs) are congenital lesions, which frequently present in young patients. The goal of treatment is a complete and durable cure, with limited neurological morbidity and mortality, and a better quality of life, for the rest of that patient's life. Unfortunately, the logistics of any trial, particularly a National Institutes of Health funded trial, initially will only accommodate follow-up for a finite period of time—5 years in the case of ARUBA. With this study design, patients allocated to intervention were exposed to the entire upfront risk of the interventional procedure(s) to achieve curative treatment of the lesion. While most patients allocated to intervention presumably underwent definitive treatment and were cured of the AVM during the trial, the benefit of this curative treatment was only realized for the relatively brief period of follow-up. At the same time, patients allocated to the medical management arm, who remain at a lifelong risk for neurological morbidity, were only tracked for a small fraction of their ‘at risk’ period. For this reason, the study design heavily favored medical management. In other words, patients undergoing treatment face the full risk posed by that treatment during the study while those allocated to medical management are …

Observer variability of an angiographic grading scale used for the assessment of intracranial aneurysms treated with flow-diverting stents.

Abstract: BACKGROUND AND PURPOSE: Novel angiographic grading scales for the assessment of intracranial aneurysms treated with flow-diverting stents have been recently developed because previous angiographic grading scales cannot be applied to these aneurysms. The purpose of this study was to evaluate the inter- and intraobserver variability of the novel O9Kelly Marotta grading scale, which was developed specifically for the angiographic assessment of aneurysms treated with flow-diverting stents. MATERIALS AND METHODS: Multiple raters (n = 31) from the disciplines of neuroradiology and neurosurgery were presented with pre- and posttreatment angiographic images of 14 aneurysms treated with intraluminal flow diverters. Raters were asked to classify pre- and posttreatment angiograms by using the OKM grading scale. Statistical analyses were subsequently performed with calculation of a generalized multirater κ statistic for assessment of inter- and intraobserver variability and by performing a Wilcoxon signed rank sum test for assessment of group differences. RESULTS: Variability analysis of the OKM grading scale yielded substantial (κ = 0.74) and almost perfect (κ = 0.99) inter- and intraobserver agreement, respectively, with no statistically significant differences between raters with a background of neuroradiology versus neurosurgery or attending physician versus trainee. CONCLUSIONS: The OKM grading scale for the assessment of intracranial aneurysms treated with flow-diverting stents is a reliable grading scale that can be used equally well by users of varying backgrounds and levels of training. Comparison with interobserver variability of pre-existing angiographic grading scales shows equal or better performance.

Novel aneurysm neck reconstruction device: initial experience in an experimental preclinical bifurcation aneurysm model

Abstract: Introduction Treatment of wide-necked bifurcation aneurysms often poses procedural and long-term outcome challenges. The initial preclinical experience with the Pulsar Vascular Aneurysm Neck Reconstruction Device (PVANRD) in a canine bifurcation model is described. Methods Experimental bifurcation vein pouch aneurysms were surgically created in the carotid arteries of eight dogs. Endovascular coiling of the aneurysms with assistance of the PVANRD was performed in all cases with acute performance compared with Y-stenting. Results Twelve devices were deployed in the eight cases. Deployment of the devices was straightforward and successfully protected the parent artery and maintained patency of the bifurcation in all cases, despite the use of oversized coils. Conclusion The PVANRD is a novel bifurcation stent that facilitates treatment of wide-necked bifurcation aneurysms compared with currently available adjunctive devices.

Abstract 156: SAMMPRIS Angiography Discloses Hemodynamic Effects of Intracranial Stenosis: Computational Fluid Dynamics of Fractional Flow

Abstract: Background: Pressure gradients across an intracranial stenosis, or fractional flow (FF), may identify the hemodynamic significance of symptomatic lesions. Computational fluid dynamic (CFD) simulations on 3D morphology of such lesions can calculate these pressure gradients and model effects of systemic physiology interacting with these lesions, such as hypotension and induced hypertension. We studied SAMMPRIS angiography to calculate FF across symptomatic intracranial stenoses and modeled the downstream effect of systemic blood pressure (BP) fluctuations. Methods: Conventional angiography of symptomatic intracranial stenoses in the SAMMPRIS trial was converted from biplanar images to a 3D geometric mesh. CFD simulations were conducted with Ansys CFX on a Cray supercomputer to calculate FF derived from distal/proximal pressure gradients for each of 3 inflow conditions: normal BP (120/80 mm Hg), hypotension (90/60 mm Hg) and hypertension (180/120 mm Hg). Abnormal FF was defined as ≤ 0.8 during diastole to define hemodynamic significance of a stenosis. Results: 407 patients with 70-99% symptomatic stenosis had conventional angiography with biplanar views available for 3D reconstruction in 249, and CFD simulations in 188 (25 VA, 45 BA, 32 ICA, 86 MCA). Under simulated normal inflow conditions (120/80 mm Hg), only 76/188 (40%) cases had low FF. During simulated hypertension, FF improved to normal in 10/188 (5%) cases. Simulated hypotension caused FF to worsen from normal in 12/188 (6%) cases. Other hemodynamic parameters including shear stress could also be calculated and visually depicted in all cases. Conclusions: CFD and hemodynamic modeling of FF can be retrospectively performed after 3D conversion of biplanar angiogram views. FF estimates predict that only 40% of severe (70-99%) symptomatic intracranial stenoses are hemodynamically significant. Systemic BP fluctuations can be modeled during phases of the cardiac cycle to show downstream flow changes.

Demand–supply of neurointerventionalists for endovascular ischemic stroke therapyAuthor Response

Abstract: Editors' Note: Drs. Fiorella and Cloft and authors Zaidat et al. discuss the impending oversupply of neurointerventionalists and echo debates ongoing in many medical subspecialties, namely, how to construct barriers to decrease the number of people entering a field. Between 2005 and 2007, the United Council of Neurologic Subspecialties created 7 new board examinations, complete with rigid application requirements. It is hard not to view these barriers as potentially self-serving. Many of the people initiating additional fellowships and new board examinations have managed well in their fields without those hurdles. While it is difficult to argue against more education, these requirements have a time and financial cost for trainees (and their departments) and could contribute to fragmentation within the field. Megan Alcauskas, MD, and Robert C. Griggs, MD …

Intracranial Stenting SAMMPRIS

Abstract: The Stenting and Aggressive Medical management for the Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial established aggressive medical management as superior to angioplasty and stenting for symptomatic intracranial atherosclerotic disease. This presentation addressessome criticisms of the trial, emphasizes key knowledge gained from the study and proposes potential new directions for research in this area.

In Vitro Quantification of the Size Distribution of Intrasaccular Voids Left After Endovascular Coiling of Cerebral Aneurysms

Abstract: Endovascular coiling of cerebral aneurysms remains limited by coil compaction and associated recanalization. Recent coil designs which effect higher packing densities may be far from optimal because hemodynamic forces causing compaction are not well understood since detailed data regarding the location and distribution of coil masses are unavailable. We present an in vitro methodology to characterize coil masses deployed within aneurysms by quantifying intra-aneurysmal void spaces. Eight identical aneurysms were packed with coils by both balloon- and stent-assist techniques. The samples were embedded, sequentially sectioned, and imaged. Empty spaces between the coils were numerically filled with circles (2D) in the planar images and with spheres (3D) in the three-dimensional composite images. The 2D and 3D void size histograms were analyzed for local variations and by fitting theoretical probability distribution functions. Balloon-assist packing densities (31 ± 2%) were lower (p = 0.04) than the stent-assist group (40 ± 7%). The maximum and average 2D and 3D void sizes were higher (p = 0.03–0.05) in the balloon-assist group as compared to the stent-assist group. None of the void size histograms were normally distributed; theoretical probability distribution fits suggest that the histograms are most probably exponentially distributed with decay constants of 6–10 mm. Significant (p ≤ 0.001 to p = 0.03) spatial trends were noted with the void sizes but correlation coefficients were generally low (absolute r ≤ 0.35). In conclusion, the methodology we present can provide valuable input data for numerical calculations of hemodynamic forces impinging on intra-aneurysmal coil masses and be used to compare and optimize coil configurations as well as coiling techniques.

O-009 Safety of flow diversion: Results from a multicentre registry

Abstract: Purpose To determine the rates of neurologic adverse events following Pipeline Embolic Device (PED) placement for intracranial aneurysm treatment. Methods A retrospective review of medical records was performed at 19 centres to identify consecutive intracranial aneurysms treated with the PED following regulatory approval for marketing the device in the given country. All patients in whom at least one PED was placed and in whom follow-up was available prior to IRB or ethics panel approval were enrolled. Three anatomic/size subgroups were defined, including 1) pre-PComm, internal carotid artery aneurysms 10mm or greater (“large ICA”), 2) ICA aneurysms >10mm and/or at/distal to the PComm region (“other anterior circulation”), and 3) posterior circulation aneurysms. “Primary safety events” included stroke, haemorrhage, parent artery stenosis, permanent cranial neuropathy, and spontaneous rupture of the target aneurysm. Severe safety events were defined as any event causing significant impairment of functioning causing the inability of the subject to carry out usual activities. Statistical analysis was performed using standard summary statistics; p-values comparing subgroups were computed using Pearson9s chi-square test for discrete variables and analysis of variance for continuous variables. Results To date, 580 aneurysms, including 183 large ICA, 344 other anterior circulation, and 53 posterior circulation aneurysms have been treated and followed for a mean duration of 7.8 months (SD 7.3, range 0.1 - 40.8). 437 (76%) of 580 aneurysms were saccular and 80 (14%) were fusiform; 32 (5.5%) were classified as giant ( Conclusions Preliminary data indicates that in approximately 7% of aneurysms treated with PED, substantial neurologic complications occurred, with rates of both severe neurologic events and mortality occurring significantly higher in the posterior as compared to the anterior circulation. Both ipsilateral haemorrhage and spontaneous aneurysm rupture were rare, with the latter event limited to giant aneurysms. Disclosures D. Kallmes: 1; C; MicroVention, Sequent, Benvenue, eV3. 2; C; General Electric, Codman, eV3. E. Boccardi: None. A. Bonafe: None. S. Cekirge: None. D. Fiorella: 2; C; Pipeline proctor, consultant, (

Abstract WP164: Role of Risk Factors in the Paradoxical Effect of Smoking on Peri-procedural Stroke in SAMMPRIS

Abstract: Background: A previous SAMMPRIS analysis of patients randomized to stenting showed that peri-procedural ischemic infarcts were significantly associated with diabetes, basilar stenosis, age, and smoking status with never smokers having a higher risk (odds ratio = 8.8, p Method: Baseline features in 213 patients undergoing stenting in SAMMPRIS were compared between never smokers vs. former and current smokers in univariate and multivariate analyses. Logistic regression was used to determine the effect of smoking on peri-procedural ischemic infarcts after adjusting for factors related to smoking. Data: Univariate results are shown in Table 1. Never smokers were significantly (P Conclusion: While never smokers had significantly higher rates of some risk factors compared to active or previous smokers, these risk factors do not explain all the increased risk of early stroke in never smokers after stenting in SAMMPRIS. Another contributory factor may be that smoking accelerates the conversion of clopidogrel to its active form.

Abstract TP407: Participant Satisfaction With a Lifestyle Management Program in the SAMMPRIS Clinical Trial

Abstract: Background: SAMMPRIS was the first secondary prevention stroke trial to provide a lifestyle modification program to all clinical trial participants. We sought to determine if SAMMPRIS participants ...

Interventional treatment of acute ischemic stroke: introduction.

Abstract: The only treatment shown to improve outcome in acute ischemic stroke is tissue-type plasminogen activator administered within 3 hours (and perhaps longer) after stroke onset.1–3 Definitive data to support a role for acute endovascular stroke therapy, however, are lacking. Despite this lack of data, endovascular therapy is being used much more widely and has become the standard of care …

O-001 Pre-Treatment Imaging is Critical in Identifying Stroke Patients with Small and Medium Infarcts Who are Likely to Benefit from IA Therapy

Abstract: Introduction/Purpose The Penumbra START Trial is a multicentre, prospective, single-arm trial with a primary aim of determining whether core infarct size on pre-treatment neuroimaging predicts clinical response to intra-arterial acute stroke therapy. Materials and Methods For this study, major inclusion criteria include presence of proximal artery occlusion in the anterior circulation, baseline NIHSS score of 10 or greater, evaluable pre-treatment neuroimaging [noncontrast CT (NCCT), CTA source imaging, CT perfusion or MRI DWI], and treatment with the Penumbra System within 8 hours. Core infarct size was evaluated by a blinded imaging Core Laboratory. As pre-specified, infarcts were trichotomised into small [ASPECTS 8–10 (NCCT, CTA-SI) or lesion volume 100 cc). In total, 146 patients were enrolled at 27 centres, including 104 patients with Core Lab review and evaluation at 90 days. Good clinical outcome is defined as mRS 0–2 at 90 days. Case review is still ongoing, and statistical analysis is from the 104 patients with complete information. We will update results at the time of the meeting. Results Mean age is 66 ± 14, including 56% females. Median baseline NIHSS score is 19 (IQR14–22), and 58% of patients had occlusions located on their left side. Overall, TIMI 2–3 revascularisation was achieved in 85%. Forty-eight patients had a good outcome at 90 days (46%); 28 patients died (27%). The number of evaluable scans for each imaging method was: 31 CTP, 82 CTA-SI, 79 NCCT, and 6 DWI. After pooling all modalities in an aggregate analysis, a statistically significant relationship was found between core infarct size and good outcome, such that worse outcomes were found only in the large infarct group. The rate of 90-day good outcome was 54% in small, 56% in medium, and 19% in large infarcts (p=0.0010), despite similar rates of recanalisation (79% small, 93% medium, 84% large). Independent predictors of good outcome were age, baseline NIHSS score, time from onset to recanalisation, and infarct volume. Thirteen patients experienced symptomatic ICH (13%). Conclusion Pre-treatment neuroimaging is important in identifying patients with large infarcts who are unlikely to respond to mechanical thrombectomy. These data support the use of rigorous imaging criteria in patient selection. Disclosures D. Frei: 3; C; Penumbra, Inc. A. Yoo: 1; C; Penumbra, Inc. D. Heck: None. F. Hellinger II: None. V. McCollom: None. D. Fiorella: None. A. Turk III: 3; C; Penumbra, Inc. T. Malisch: None. O. Zaidat: 1; C; Penumbra, Inc. 3; C; Penumbra, Inc. M. Alexander: None. Z. Chaudhry: None. R. Gonzalez: None. L. Barraza: 5; C; Penumbra, Inc. A. Bose: 4; C; Penumbra, Inc. 5; C; Penumbra, Inc. S. Sit: 5; C; Penumbra, Inc. 6; C; Penumbra, Inc.