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Variability in response to clopidogrel therapy is increasingly being recognized as an important factor in thromboembolic and hemorrhagic complications encountered after neurointerventional procedures. This study aims to determine the variability in response to clopidogrel therapy and associated complications in patients undergoing endovascular treatment of unruptured cerebral aneurysms.We recorded baseline patient characteristics, co-administered medications, P2Y12 reaction units (PRU) values with VerifyNow, clopidogrel dosing, and thromboembolic and hemorrhagic complications in patients undergoing endovascular treatment of unruptured cerebral aneurysms at our institution during a 19 month period.100 patients were included in the study, 76 women and 24 men, mean age 57.3 years. 15 patients exhibited an initial clopidogrel hypo-response (PRU240) and 21 patients an initial clopidogrel hyper-response (PRU60). 36 patients had a follow-up VerifyNow test performed without changes to the standard 75 mg daily clopidogrel dose, which demonstrated that 59% of patients who had initially been within the target 60-240 PRU range exhibited a delayed conversion to clopidogrel hyper-response. In our cohort, a clopidogrel hypo-response was associated with a significantly increased risk of thromboembolic complications in patients undergoing cerebral aneurysm treatment with stent assistance or the pipeline embolization device (60%, p=0.003), while a clopidogrel hyper-response was associated with a significantly increased risk of major hemorrhagic complications in all patients undergoing endovascular treatment of cerebral aneurysms (11%, p=0.016).We found wide and dynamic variability in response to clopidogrel therapy in patients undergoing endovascular treatment of unruptured cerebral aneurysms, which was significantly associated with thromboembolic and major hemorrhagic complications in our cohort.

Background and purpose The use of Onyx has become the mainstream for the treatment of cranial dural arteriovenous fistulas (AVFs) and arteriovenous malformations, but the reported success for type I spinal dural arteriovenous fistulas (sDAVFs) remains limited. We review our experience with Onyx and report its limitations in the treatment of spinal AVFs. Materials and methods We retrospectively reviewed the Interventional Neuroradiology Procedure database at Washington University for cases of sDAVF embolization. Radiology reports were reviewed for fistula classification, treatment technique, and initial and follow-up results. Angiographic images were reviewed to confirm diagnosis, treatment, and penetration of embolisate into the draining vein. Results With the use of Onyx, sDAVFs were obliterated in six of seven patients at the time of treatment. Follow-up angiography confirmed sDAVF obliteration in two patients, and recurrence in two cases. Two patients had no follow-up. One patient not cured at the time of treatment was treated surgically. Of the nine total treatments, Onyx successfully crossed the nidus into the draining vein in only four cases. Successful venous embolization was facilitated with positioning of the microcatheter to less than 5 mm from the nidus in three of the four cases. The use of n-butyl cyanoacrylate (NBCA) resulted in venous penetration in eight of 10 cases, and short term follow-up cure in seven of 10 patients. Conclusions Our experience with Onyx for type I sDAVF embolization has been tempered by difficulty in achieving venous penetration and, consequently, a high rate of recurrence. For management of these fistulas, we favor NBCA or surgical treatment.

BACKGROUND AND PURPOSE: A recent study identified a preprocedural P2Y12 reaction units value of 240 as a strong independent predictor of perioperative thromboembolic and hemorrhagic complications after treatment of cerebral aneurysms with the Pipeline Embolization Device. This study aimed to determine whether a last-recorded P2Y12 reaction units value of 240 predicts thromboembolic and hemorrhagic complications up to 6 months after treatment of cerebral aneurysms with the Pipeline Embolization Device in the same patient cohort. MATERIALS AND METHODS: We recorded patient and aneurysm characteristics, P2Y12 receptor antagonist administered, P2Y12 reaction units value with VerifyNow, procedural variables, and thromboembolic and hemorrhagic complications up to 6 months after Pipeline Embolization Device procedures at our institution during an 8-month period. Complications causing a permanent disabling neurologic deficit or death were considered major. Multivariate regression analysis was performed to identify independent predictors of thromboembolic and hemorrhagic complications. RESULTS: Forty-four patients underwent 48 Pipeline Embolization Device procedures at our institution during the study period. There were 11 thromboembolic and hemorrhagic complications up to 6 months after treatment in our cohort (22.9%), 5 of which were major (10.4%). A last-recorded P2Y12 reaction units value of 240 was the only independent predictor of all (P = .002) and major (P = .03) thromboembolic and hemorrhagic complications in our cohort. Most patients (71%) required, on average, 2 adjustments to the dose or type of P2Y12 receptor antagonist to remain within the 60–240 target P2Y12 reaction units range. CONCLUSIONS: In our cohort, a last-recorded P2Y12 reaction units value of 240 was the only independent predictor of all and major thromboembolic and hemorrhagic complications up to 6 months after Pipeline Embolization Device procedures.

Background and purpose The difference in the relationship between the size of intracranial aneurysms (IAs) and their risk of rupture in patients with singe IAs versus those with multiple IAs is unclear. We sought to retrospectively analyze the size of ruptured IAs (RIAs) in patients with single and multiple IAs in order to study this relationship further. Methods We retrospectively measured the size and location of RIAs in all patients who presented to our institute with an acute subarachnoid hemorrhage between 1 January 2005 and 31 December 2010. The IAs were classified by size into very small IAs or VSAs (≤3 mm), small IAs or SAs (>3 mm but ≤7 mm) and others (>7 mm). Results 379 patients (281 with a single IA, Group 1 and 98 with multiple IAs, Group 2) with 419 treated RIAs were included in the study. VSAs and SAs constituted the majority of RIAs in both groups (33.5% and 45.2% in Group 1 and 24.6% and 50.7% in Group 2) and the mean size of the RIAs was not different between the two groups. VSAs constituted almost two-thirds of all RIAs in certain locations whereas IAs > 7 mm in size did not constitute more than a third of the RIAs at any of the arterial locations. Conclusions The high incidence of VSAs, particularly in certain locations in both patient subgroups, suggests that current diagnostic, prognostic and therapeutic options in the management of IAs should be more tailored towards the management of these difficult-to-treat lesions.

To determine the safety and efficacy of internal maxillary artery (IMA) and facial artery polyvinyl alcohol (PVA) embolization for treatment of refractory idiopathic epistaxis.From 1998-2011, 84 patients were referred for endovascular treatment of intractable idiopathic epistaxis. PVA (range, 180-300 μM) particles were used in all cases. One case required microcoils to prevent nontarget embolization. Medical records were reviewed for early recurrences and complications, which were correlated with the number of vessels receiving embolization using the Mantel-Haenszel χ(2)test for linear association; P.05 was accepted for significance.Vessels chosen for embolization were unilateral IMA in 8 patients, bilateral IMAs in 35 patients, bilateral IMAs with one facial artery in 32 patients, and bilateral IMAs and bilateral facial arteries in 9 patients. Early (30 d) rebleeding requiring therapy occurred in nine patients (11%). Minor complications occurred in 22 patients (26%) and included mild facial or jaw pain, facial edema, headache, and transient ischemic attack. There was one major complication that consisted of facial skin sloughing and mild lip ulceration in a patient who had embolization of both IMAs and both facial arteries. A linear association was found when the number of vessels receiving embolization was correlated with both the rates of early recurrence (inversely, P = .04) and minor complications (P = .004).An initial treatment strategy involving embolization of bilateral IMAs with or without embolization of facial arteries for refractory idiopathic epistaxis is safe and effective. Additional facial artery embolization reduces the risk of early recurrence but increases the risk of minor complications.

Object The aim of this study was to define the optimal treatment for patients with symptomatic intraluminal carotid artery thrombus (ICAT). Methods The authors performed a retrospective chart review of patients who had presented with symptomatic ICAT at their institution between 2001 and 2011. Results Twenty-four patients (16 males and 8 females) with ICAT presented with ischemic stroke (18 patients) or transient ischemic attack ([TIA], 6 patients). All were initially treated using anticoagulation with or without antiplatelet drugs. Eight of these patients had no or only mild carotid artery stenosis on initial angiography and were treated with medical management alone. The remaining 16 patients had moderate or severe carotid stenosis on initial angiography; of these, 10 underwent delayed revascularization (8 patients, carotid endarterectomy [CEA]; 2 patients, angioplasty and stenting), 2 refused revascularization, and 4 were treated with medical therapy alone. One patient had multiple TIAs despite medical therapy and eventually underwent CEA; the remaining 23 patients had no TIAs after treatment. No patient suffered ischemic or hemorrhagic stroke while on anticoagulation therapy, either during the perioperative period or in the long-term follow-up; 1 patient died of an unrelated condition. The mean follow-up was 16.4 months. Conclusions Results of this study suggest that initial anticoagulation for symptomatic ICAT leads to a low rate of recurrent ischemic events and that carotid revascularization, if indicated, can be safely performed in a delayed manner.

BACKGROUND AND PURPOSE: The yield of DSA in patients with SAH and negative initial noninvasive neurovascular examinations (CTA or MRA) is not well-understood. This study aimed to determine the yield of DSA for the detection of causative vascular lesions in this clinical scenario. MATERIALS AND METHODS: We examined the yield of DSA for the detection of causative vascular lesions in a cohort of patients presenting to our institution with SAH and negative initial noninvasive neurovascular examinations during a 5-year period. Two experienced neuroradiologists independently evaluated the NCCT to determine the SAH pattern (diffuse, perimesencephalic, or peripheral sulcal) and the catheter angiograms to assess the presence of a causative vascular lesion. RESULTS: Fifty-five patients were included in the study, with a mean age of 58.2 years (median, 58 years; range, 25–88 years). Twenty-eight patients were men (50.9%), and 27 were women (49.1%). The initial noninvasive examination was a CTA in 47 patients (85.5%) and an MRA in 8 patients (14.5%). Thirty-three patients had diffuse SAH (60%); 11, perimesencephalic SAH (20%); and 11, peripheral sulcal SAH (20%). DSA demonstrated a causative vascular lesion in 6 patients (10.9%), 5 of whom had diffuse SAH (yield of 15.2%) and 1 of whom had peripheral sulcal SAH (yield of 9.1%). No causative vascular lesions were found in patients with perimesencephalic SAH. CONCLUSIONS: DSA is a valuable tool in the evaluation of patients with diffuse and peripheral sulcal SAH who have negative initial noninvasive neurovascular examinations, demonstrating a causative vascular lesion in 15.2% and 9.1% of patients, respectively.

Introduction Dual antiplatelet therapy (DAPT) with aspirin and a thienopyridine (eg, clopidogrel) prevents stent related thromboembolic events in cardiac patients and is frequently utilized during neurointerventional surgery. However, recent data suggest that many patients exhibit clopidogrel resistance. Prasugrel—a newer thienopyridine—lowers the rate of cardiac stent thromboses in clopidogrel non-responders but a paucity of data exist regarding its safety and efficacy in neurointerventional surgery. Methods All patients undergoing neurointerventional surgery by a single interventionalist (CJM) over a 20 month period were retrospectively identified. Charts were reviewed for pre- and post-procedural DAPT regimens, pre-procedural coagulation parameters and procedural complications. Results 76 patients received pre- and post-procedural DAPT for endovascular treatment of an intracerebral aneurysm, dural arteriovenous fistula or intra/extracranial arterial stenosis. 51 patients underwent 55 total procedures and were treated with aspirin/clopidogrel; 25 patients underwent 31 total procedures and were treated with aspirin/prasugrel. Those patients who received aspirin/prasugrel DAPT were identified pre-procedurally to be clopidogrel non-responders. Both treatment groups had a similar percentage of patients undergoing aneurysm coiling, stent assisted aneurysm coiling, aneurysm Onyx embolization, aneurysm pipeline embolization device treatment, extra/intracranial carotid artery angioplasty and stenting, and dural arteriovenous fistula coil embolization. A total of eight (9.3%) hemorrhagic complications were observed, two (3.6%) in the aspirin/clopidogrel group and six (19.4%) in the aspirin/prasugrel group (p=0.02). No differences were noted in hemorrhage rates for each procedure between treatment groups, nor were there any differences in thrombotic complications between groups. Conclusion Our results suggest that DAPT with aspirin/prasugrel may predispose to a higher risk of hemorrhage during neurointerventional surgery compared with DAPT with aspirin/clopidogrel.

Backgroun and objective Coiling of wide-necked basilar tip aneurysms is technically challenging and is often assisted by the placement of a stent. Stent placement in an anterograde fashion either with a single or Y-stent is typical. However, in some cases the posterior cerebral artery (PCA) angle of origin at the base of the aneurysm precludes anterograde catheterization. A series of patients with wide-necked basilar tip aneurysms treated with a single stent placed via the posterior communicating artery from PCA to PCA is presented. Methods A retrospective database review was performed to identify all stent-coiled basilar tip aneurysms. Patients with attempted horizontal P1eP1 stenting via the posterior communicating artery were identified. Procedural imaging, follow-up angiography and clinical notes were reviewed. Results P1eP1 stenting was attempted in 10 patients and was successful in eight. Angiographic follow-up was available in six patients, all of whom had >90% obliteration at last follow-up. There was one procedurerelated subarachnoid hemorrhage that resulted in patient death. There were no cases of significant PCA stenosis on angiographic follow-up. Conclusions This stenting technique is an effective way to treat wide-necked basilar tip aneurysms but is limited by the anatomy of the posterior communicating arteries and P1 segments.

Background and purpose Since 2002 the Neuroform stent has expanded endovascular treatment of widenecked intracranial aneurysms. A study was undertaken to assess the technical success rates and angiographic and clinical outcomes in stent-assisted coiling with Neuroform 1, 2, 2 Treo and 3. Methods Patients undergoing Neuroform stent-assisted coiling were enrolled in a prospective registry that included 156 stent deployment attempts in 113 consecutive patients (mean age 53, range 25e78). Deployment success and difficulty, stent movement, procedural complications, immediate/delayed aneurysm occlusion and in-stent stenosis on angiographic follow-up were compared among Neuroform 1, 2, 2 Treo and 3 stents using a log likelihood ratio c 2 test. Results Of 156 stent attempts, 123 (79%) were deployed (Neuroform 1: 8/9 (89%), Neuroform 2: 50/66 (76%), Neuroform 2 Treo: 9/11 (82%), Neuroform 3: 56/ 70 (80%)) with a symptomatic complication rate of 1.9% (3/156; 2 transient ischemic attacks, 1 stroke, no deaths). Non-target stent placement (1/8 (13%), 6/50 (12%), 2/9 (22%), 3/56 (5%)), difficult placement (2/8 (25%), 10/50 (20%), 5/9 (56%), 6/56 (11%)), stent movement (1/8 (13%), 4/50 (8%), 0/9 (0%), 4/56 (7%)), procedural complications (1/9 (11%), 7/66 (11%), 2/11 (18%), 2/70 (3%)) and immediate near complete aneurysm occlusion (6/6 (100%), 24/37 (65%), 5/7 (71%), 40/45 (89%)) trended towards improvement with each generation. Improvements in difficult stent placement and immediate aneurysm occlusion were significant (p¼0.01 and 0.03, respectively). Conclusion Neuroform stent-assisted coiling has evolved through four generations as a safe and effective means of treating wide-necked intracranial aneurysms.

To investigate the technical success rate as well as the procedural and mid-term complication rates of carotid angioplasty and stenting in elderly patients, a group excluded from large randomized endarterectomy trials given their perceived high surgical risk.Of 200 consecutive carotid angioplasty and/or stenting procedures performed between March 1996 and March 2005, 21 procedures were performed without cerebral protection devices in 20 patients over the age of 79 years (mean age: 83 years, 12 men, eight women). These patients' medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and mid-term complication rates were calculated and compared to a previously published cohort of 133 consecutive patientsor = 79 years of age who also underwent endovascular treatment at our institution.Carotid stenosis was reduced from a mean of 82% to no significant stenosis in all procedures. The procedural stroke rate was zero of 21 procedures. The procedural transient ischemic attack rate (TIA) was one of 21 procedures (4.8%). Mean follow-up was 24.6 months (range: 1.0-79.5 months) with at least a 30-day follow-up for 20 of the 21 procedures (95.2%). There were no new strokes. There was one recurrent ipsilateral TIA at 1.9 months. In five cases with follow-up carotid ultrasonography, no hemodynamically significant restenosis had occurred. There were three myocardial infarctions (MI) occurring at 0.5, 2.1, and 15.2 months, of which the last MI was fatal. The composite 30-day stroke and death rate was zero of 21 procedures (95% confidence interval: 0-14%). No significant difference was found in the 30-day rate of stroke, TIA, MI, or death between the elderly and younger patients.Carotid angioplasty and stenting in elderly patients can be performed successfully with acceptable procedural and mid-term complication rates comparable to younger patients.

Postpartum reversible cerebral vasoconstriction syndrome (PPRCVS) is a rare but serious cause of headache that occurs in the early postpartum period. The rarity of this disorder has limited the current literature to single case reports and small, observational case series. The lack of familiarity with PPRCVS may contribute to mismanagement of these unique patients and lead to poor outcomes. To address current gaps in the understanding of PPRCVS, this review and data analysis characterizes the demographics, presentation, clinical course, management and prognosis of PPRCVS and provides a general review of the epidemiology, pathophysiology and diagnosis to assist clinicians who may care for patients with this rare disorder.

Object The goal in this retrospective study was to examine the procedural complication rate for carotid angioplasty and stent placement performed without cerebral protection devices. Methods Between March 1996 and December 2003, 167 carotid angioplasty and/or stent placement procedures were performed without cerebral protection devices in 152 patients (57 women and 95 men whose mean age was 64 years, range 19–92 years). Seven of these patients underwent angioplasty alone. Eighty-nine patients presented with focal neurological symptoms. Indications for surgery included atherosclerosis, radiation-associated stenosis, dissection, pseudoaneurysm, and stretched endovascular coils from aneurysm treatment. In this study, the patients' medical records were reviewed for clinical characteristics, techniques used, and resulting intraprocedural and 30-day complication rates. The intraprocedural stroke rate was four (2.4%) of 167; this included three hemispheric strokes and one retinal embolus. All events occurred in patients who had symptomatic stenosis. The procedural transient ischemic complication rate was six (3.6%) of 167, as was the procedural nonneurological complication rate. During the 30 days post-procedure, one patient had died and three had suffered permanent ischemic events (two cerebral and one ocular). The composite 30-day postprocedural stroke and death rate was eight (5%) of 160. The rate of asymptomatic angiographically confirmed abnormalities was 0.6% (one treated vessel that was occluded but asymptomatic). The 30-day rate of nonneurological complications was 2.5%. A strong association between intraprocedural thromboembolic events (eight cases) and prior ischemic symptoms was found (p = 0.01). Conclusions Carotid angioplasty and stent placement without cerebral protection devices is safe, particularly in patients without symptomatic stenosis.

To retrospectively determine the sensitivity and specificity of cerebral angiography for the diagnosis of primary angiitis of the central nervous system (CNS).Institutional review board approval was obtained, and informed consent was not required. Thirty-eight patients (13 men, 25 women; mean age, 55 years) had undergone cerebral angiography followed by cortical and leptomeningeal biopsy for possible primary angiitis of the CNS during an 8-year period. Angiography reports were reviewed by investigators blinded to the results of biopsy. Angiographic findings were categorized as typical for vasculitis, normal, or other. Sensitivity and specificity of cerebral angiography for the diagnosis of primary angiitis of the CNS were calculated.Fourteen patients had typical angiographic findings of vasculitis. None had primary angiitis of the CNS at brain biopsy (60% specificity). Specific pathologic diagnoses other than primary angiitis of the CNS were made in six patients. Findings of brain biopsy in the remaining eight patients were nondiagnostic. Repeat angiograms were obtained in three of the eight patients. One patient demonstrated interval improvement in multiple focal intracranial arterial stenoses and two demonstrated worsening. Primary angiitis of the CNS was found at biopsy in two of the remaining 24 patients (0% sensitivity). One of the two patients had slow filling of a single distal cortical artery, and the other patient had multiple regions of abnormally prolonged capillary blush.In this series, patients suspected of having primary angiitis of the CNS on the basis of clinical and angiographic findings did not have primary angiitis of the CNS at biopsy. Typical angiographic findings of primary angiitis of the CNS are often associated with other specific pathologic diagnoses, which emphasizes the importance of brain biopsy.

BACKGROUND The endovascular treatment of middle cerebral artery (MCA) aneurysms has been controversial because of the frequency of complex anatomy and the relative ease of surgical clipping in this location. OBJECTIVE To present a large single-center experience with the endovascular treatment of MCA aneurysms. METHODS The neurointerventional database at our institution was reviewed for all endovascular treatments of MCA aneurysms. Demographics, aneurysm characteristics, treatment modality, intraprocedural hemorrhagic and thromboembolic events, 30-day neurological events, and follow-up angiographic studies were recorded. RESULTS From December 1996 to April 2013, 292 patients underwent endovascular treatment of 346 MCA aneurysms. Of these, 341 (98.6%) were successfully completed. Balloon neck remodeling was used in 230 procedures (66.5%). Ninety-five procedures (27.4%) were for ruptured aneurysms. The rate of intraprocedural hemorrhage was 2.6% (9 of 346). The overall rate of intraprocedural thromboembolic events was 13.6% (47 of 346), significantly more common in patients with acute subarachnoid hemorrhage (27.4%; P 2) neurological event rate was 2.9% (10 of 346), significantly more common in patients with subarachnoid hemorrhage (8.4%) compared with those without (0.8%; P < .001). The rate of complete or near-complete aneurysm occlusion at was 90.6% ≥ 6 months and 91.8% at ≥ 2 years, with an average of 24 months of follow-up available for 247 procedures. CONCLUSION Endovascular treatment of MCA aneurysms can be safe and effective. However, it is associated with a high asymptomatic thromboembolic event rate that is more frequent in the setting of acute subarachnoid hemorrhage.

Introduction. The best treatment for unruptured middle cerebral artery (MCA) aneurysms is unclear. We perform a meta-analysis of recent publications to evaluate the results of unruptured MCA aneurysms treated with surgical clipping and endovascular coiling.Methods. A PubMed search for articles published between January 2004 and November 2013 was performed. The R statistical software package was used to create a random effects model for each desired incidence rate. Cochran’sQtest was used to evaluate possible heterogeneity among the rates observed in each study.Results. A total of 1891 unruptured MCA aneurysms, 1052 clipped and 839 coiled, were included for analysis. The complete occlusion rate at 6–9 months mean follow-up was 95.5% in the clipped group and 67.8% in the coiled group (P<0.05). The periprocedural thromboembolism rate in the clipping group was 1.8% compared with 10.7% in the aneurysms treated by coiling (P<0.05). The recanalization rate was 0% for clipping and 14.3% for coiling (P=0.05). Modified Rankin scores of 0–2 were obtained in 98.9% of clipped patients compared to 95.5% of coiled (NS).Conclusions. This review weakly supports clipping as the preferred treatment of unruptured MCA aneurysms. Clinical outcomes did not differ significantly between the two groups.

Background and purpose Patients who require sacrifice of the internal carotid artery (ICA) have a substantial risk of stroke, despite preoperative testing with temporary balloon occlusion (TBO). The purpose of this study is to examine the incidence and mechanisms of stroke after permanent carotid artery occlusion in this population. Methods Consecutive patients undergoing TBO testing from March 2002 to December 2011 were identified. The protocol included 30 min of balloon occlusion, continuous intraprocedural neurological assessment, angiographic imaging of collateral flow during the occlusion, and perfusion imaging. Clinical records were reviewed for procedure results, procedural complications, and the incidence and causes of stroke, transient ischemic attack (TIA) and death over 6 months. Strokes were categorized as thromboembolic or hypoperfusion based on available clinical and imaging data. Results One hundred and fifty carotid occlusion tests were performed during the study period, including 84 women and 66 men. No procedural strokes were recorded. Thirty-seven patients (25%) had permanent occlusion of the tested ICA. Six of the 37 patients had ipsilateral stroke (16.2%) and three experienced TIA (8.1%). Two strokes occurred in the immediate postoperative period (thromboembolic), two strokes occurred within days of ICA occlusion (hypoperfusion), and two strokes occurred at least 30 days from the time of ICA occlusion (thromboembolic). Conclusions The rate of ischemic stroke following carotid sacrifice remains high and most strokes are thromboembolic in nature. Our testing protocol did not eliminate the risk of hypoperfusion-related stroke. Delayed venous phase by angiography may be a better indicator of hemodynamic tolerance than perfusion imaging.

Purpose The yield of delayed neurovascular imaging in patients with subarachnoid hemorrhage (SAH), negative initial CT and catheter angiograms (CT angiography (CTA), DSA), and negative 7 day repeat DSA is not well understood. Our aim was to determine the yield of delayed neurovascular imaging for the detection of causative vascular lesions in this clinical scenario. Methods We retrospectively examined the yield of delayed CTA and DSA for the detection of causative vascular lesions in patients presenting to our institution with SAH, negative initial CTA and DSA examinations, and a negative 7 day repeat DSA during a 6.5 year period. Two neuroradiologists evaluated the non-contrast CTs to determine the SAH pattern, and the delayed CTAs and DSAs to assess for the presence of a causative vascular lesion. Results 39 patients were included: 23 men (59%) and 16 women (41%), mean age 55.5 years (range 33–75). 25 patients had diffuse SAH (64.1%), 12 had perimesencephalic SAH (30.8%), and two had peripheral sulcal SAH (5.1%). The delayed neurovascular examination was CTA in 30 patients (76.9%) and DSA in nine patients (23.1%). Mean time to delayed CTA or DSA was 34.9 days (median 34, range 14–69 days). Delayed CTA demonstrated a causative vascular lesion in two patients (5.1%, one small internal carotid artery aneurysm and one small pontine arteriovenous malformation), both with diffuse SAH (yield 8%). Conclusions Delayed neurovascular imaging is valuable in the evaluation of patients with diffuse SAH who have negative initial CTA and DSA examinations and a negative 7 day repeat DSA, demonstrating a causative vascular lesion in 8% of patients.

BACKGROUND The angle of the basilar artery bifurcation of (BAB angle) is thought to influence the risk of the development and rupture of aneurysms at this site. It is, however, unknown whether the BAB angle also influences the incidence of angiographically negative perimesencephalic subarachnoid hemorrhage (PMSAH). OBJECTIVE We performed a retrospective cross-sectional study comparing the BAB angle in a series of patients who presented with subarachnoid hemorrhage from a ruptured aneurysm at the top of the basilar artery (BSAH) with the BAB angle in a series of patients who presented with PMSAH. METHODS Consecutive patients who presented to our institution with PMSAH or BSAH between January 1, 2005 and December 31, 2010 were studied. Patients with PMSAH were further subdivided into patients with classic PMSAH (CPMSAH) and those with nonclassic PMSAH (NCPMSAH) based on initial head computed tomography examinations. In each patient, the BAB angle was measured on the standard cranial anteroposterior projections after vertebral artery injections. RESULTS A total of 21 patients with CPMSAH, 30 patients with NCPMSAH, and 31 patients with BSAH were studied. The BAB angle was significantly smaller in patients with CPMSAH (87.7 ± 17.1 degrees) and NCPMSAH (98.4 ± 21.1 degrees) compared with patients with BSAH (135.0 ± 30.8 degrees) (P < .001). CONCLUSION The significantly lower BAB angle in PMSAH patients compared with BSAH patients suggests that bleeding in PMSAH is either nonarterial in nature or is secondary to variations in hemodynamic arterial stress at the top of the basilar artery that need to be studied further with computational models.

The Enterprise stent is the first closed-cell stent designed to treat wide-necked intracranial aneurysms. Advantages of the design can include improvement in keeping coils within an aneurysm and the ability of the stent to be recaptured. We compared the technical and clinical complications of the Enterprise stent with the open-cell Neuroform stent, its primary alternative.Patients undergoing Enterprise and Neuroform stent-assisted aneurysm coiling were enrolled in prospective registries starting in March 2007 and February 2003, respectively. All consecutive patients through December 2011 were included. Deployment success and difficulty, stent movement and misplacement, and procedural complications were compared.Enterprise deployment success was high (108 of 115 attempts, 93.9%) with 102 aneurysms receiving a stent compared with Neuroform (173 of 214 attempts, 80.8%, p = 0.001) with 163 aneurysms. Enterprise was easier to deploy (1.7% vs 15.9% difficult deployment, p0.0001). There were no significant differences in the rates of stent movement, misplacement, or symptomatic hemorrhage. Symptomatic thromboembolic events, however, were more frequent with the Enterprise stent (8.7% vs 1.4%, p = 0.0021). The Enterprise stent enabled treatment of 10 additional aneurysms that could not be treated with Neuroform and had a higher rate of immediate aneurysm occlusion (87.3% vs 73.0%, p = 0.0058).Enterprise was easier to deploy and enabled treatment of additional aneurysms; however, there were more thromboembolic complications. On the basis of these findings, we prefer to use the Neuroform stent first and rely on the Enterprise stent as an easy-to-deliver backup for stent-assisted coiling.

Background: Delayed ipsilateral intraparenchymal hemorrhage (IPH) has been reported following technically successful treatment of intracranial aneurysms using flow-diverting stents (Pipeline embolization device) in 8.5% of patients and does not appear to be related entirely to dual antiplatelet therapy. We report a similar phenomenon in Neuroform-assisted coiling. Methods: Neuroform-assisted coiling patients were entered into a prospective registry at our institution. Procedural and 30 day complications were recorded. Delayed ipsilateral IPH cases within 30 days were reviewed. Results: Between 11/2002 and 7/2012, 98 patients had Neuroform-assisted coiling of 100 cerebral aneurysms, 8 acutely ruptured. Intra-procedurally, there were 3 thromboembolic events and 4 hemorrhages due to vessel or aneurysm perforation (not necessarily symptomatic). After the procedure but within 30 days follow-up (available for 92 patients), there were 6 TIA’s, 2 minor strokes and 1 SAH. There were 2 cases of ipsilateral IPH (2%). One was a 60-year-old man who had stent-assisted coiling of an ACOM aneurysm (Neuroform from right A1 into left A2). He was on aspirin 81 mg and clopidogrel 75 mg daily with a PRU (P2Y12 reaction units) of 72 on day of procedure. Despite decreasing clopidogrel dosing to every other day, he had a frontal lobe IPH 7 days later (Figure 1) with a PRU of 59. The other IPH (Figure 2) occurred in a 70-year-old man 14 days after Y-stent assisted coiling of an MCA aneurysm. He was on clopidogrel 75 mg and warfarin (INR 2.0) for prior pulmonary embolism and dural venous sinus thrombosis. Both patients recovered without neurological deficit. Conclusion: Recently described in flow diversion, delayed ipsilateral IPH is not limited to flow-diverting stents. Though less frequent, a potential for this may exist following any intracranial stenting procedure, possibly related to hemorrhagic conversion of microembolic phenomenon while on dual antiplatelets or anticoagulation.

Purpose: To determine the number of clopidogrel or prasugrel dose adjustments needed and final DAT regimen used to maintain patients undergoing Pipeline Embolization Device (PED) procedures within a target P2Y12 inhibition range. Methods: We recorded the number of clopidogrel or prasugrel dose adjustments, final DAT regimen and thromboembolic and hemorrhagic complications in patients undergoing PED procedures at our institution over an 8-month period. P2Y12 inhibition was measured with VerifyNow 10 and 30 days after dose adjustments (target range 80-200 P2Y12 reaction units). Patients received 325mg aspirin daily. Results: Forty-four patients underwent PED procedures at our institution during the study period, 36 female and 8 male, mean age 59 years (median 63 years, range 31-81 years). Thirteen patients did not require dose adjustments to remain within the target P2Y12 inhibition range (30%). Thirty-one patients required dose adjustments to remain within the target P2Y12 inhibition range (70%), with a mean of 2.1 dose adjustments per patient (median 2, range 1-5), and a mean time from initiation of DAT to last dose adjustment of 47.5 days (median 42 days, range 8-149 days). Four patients exceeded the target P2Y12 inhibition range after a dose adjustment (13%, 3 prasugrel, 1 clopidogrel), without complications. The table summarizes the final DAT regimen and associated major thromboembolic and hemorrhagic complications leading to death or a permanent neurological deficit in our cohort. Most major complications (80%) occurred in patients who were outside the target P2Y12 inhibition range shortly before or at the time of the complication. Conclusion: The majority of patients undergoing PED procedures in our cohort (70%) required an average of 2 clopidogrel or prasugrel dose adjustments to remain within a target P2Y12 inhibition range. Future research is needed to determine if active management of DAT may decrease the risk of major complications after PED procedures.

Purpose: To determine the medium-term angiographic outcome and packing density threshold for complete aneurysm occlusion at follow-up in a series of cerebral aneurysms treated with a single coil. Methods: We retrospectively identified all cerebral aneurysms treated with a single coil at our institution from July 1997 until September 2011. We recorded aneurysm dimensions, neck size, packing density, and follow-up catheter or MR angiograms to determine the angiographic outcome at last follow-up according to the Raymond scale. We then performed receiver operating characteristic (ROC) analysis of the likelihood of complete aneurysm occlusion at follow-up to determine the packing density maximum operating point (MOP). Results: Eighty-one aneurysms in 79 patients were treated with a single coil at our institution during the study period. Sixty-four patients were female (81%) and mean age was 53 years (range 23-87 years). Mean maximum aneurysm dimension was 2.8mm (range 1.6-4.8mm), and mean dome-to-neck ratio was 1.3 (median 1.3, range 0.8-1.9). Mean aneurysm packing density was 35.3% (median 32.8%, range 10.2-94.3%). Three patients with ruptured aneurysms died during the hospitalization (7.7%), and follow-up angiographic examinations were performed in 65 patients with 67 aneurysms (85.9%). Mean time to last angiographic follow-up was 26.4 months (range 4-102 months). Complete aneurysm occlusion at last follow-up was present in 46 aneurysms (68.7%), a neck remnant in 16 aneurysms (23.9%) and sac recanalization in 5 aneurysms (7.4%). ROC analysis of the likelihood of complete aneurysm occlusion at last follow-up yielded a packing density MOP of >36.3%, with a specificity of 85.7%, sensitivity of 47.8%, and an area under the curve of 0.61 (95%CI 0.49-0.73). There was a statistically-significant difference in the likelihood of complete aneurysm occlusion at last follow-up between the 25 aneurysms with a packing density >36.3% (88%), and the 42 aneurysms with a packing density ≤36.3% (57.1%, OR 5.5 [95%CI 1.4-21.3], p-value 0.009). Conclusion: Achieving a packing density >36.3% predicts a significantly higher likelihood (88%) of complete aneurysm occlusion at medium-term angiographic follow-up in cerebral aneurysms treated with a single coil.

The aim of this study was to define the optimal treatment for patients with symptomatic intraluminal carotid artery thrombus (ICAT).The authors performed a retrospective chart review of patients who had presented with symptomatic ICAT at their institution between 2001 and 2011.Twenty-four patients (16 males and 8 females) with ICAT presented with ischemic stroke (18 patients) or transient ischemic attack ([TIA], 6 patients). All were initially treated using anticoagulation with or without antiplatelet drugs. Eight of these patients had no or only mild carotid artery stenosis on initial angiography and were treated with medical management alone. The remaining 16 patients had moderate or severe carotid stenosis on initial angiography; of these, 10 underwent delayed revascularization (8 patients, carotid endarterectomy [CEA]; 2 patients, angioplasty and stenting), 2 refused revascularization, and 4 were treated with medical therapy alone. One patient had multiple TIAs despite medical therapy and eventually underwent CEA; the remaining 23 patients had no TIAs after treatment. No patient suffered ischemic or hemorrhagic stroke while on anticoagulation therapy, either during the perioperative period or in the long-term follow-up; 1 patient died of an unrelated condition. The mean follow-up was 16.4 months.Results of this study suggest that initial anticoagulation for symptomatic ICAT leads to a low rate of recurrent ischemic events and that carotid revascularization, if indicated, can be safely performed in a delayed manner.

INTRODUCTION: The Enterprise (Codman, Raynham, MA) is the first closed-cell stent designed to treat wide-necked intracranial aneurysms. Advantages of the design can include improvement in keeping coils within the aneurysm and the ability of the stent to be partially deployed and recaptured. We compared the technical and clinical complications of the Enterprise with the Neuroform (Stryker, Kalamazoo, MI). METHODS: Between March 2007 and June 2011, Enterprise stent-assisted coil embolization was attempted for 106 aneurysms in 96 patients (mean age 58, 81 female) who were enrolled in a prospective registry. Deployment success and difficulty, stent movement and misplacement, and 30 day symptomatic neurological events were compared with a prospective cohort of patients treated with all generations of the Neuroform using a two-tailed Fisher exact test with p < 0.05 accepted for significance. RESULTS: Enterprise stent deployment success was high (107 of 113 attempts, 94.7%) with 101 of the 106 aneurysms receiving a stent. The delivery microcatheter could not be positioned in 5 cases. Two stents were deployed with difficulty (1 guide catheter change and 1 recapture prior to deployment). Six cases required a second stent for misplaced stents (n = 4), stent movement on coiling attempt (n = 1) and down-sizing because a longer stent could not be unsheathed (n = 1). There were 12 periprocedural thromboembolic or hemorrhagic events consisting of 7 transient ischemic attacks (TIA), 3 ischemic strokes and 2 intracranial hemorrhages. One TIA was attributed to non-compliance with antiplatelet therapy. One hemorrhage presented 2 days later, thought to be related to antiplatelet therapy. Results are compared with the Neuroform in the table below. CONCLUSION: The Enterprise is significantly easier to deploy than the Neuroform; however, there are more thromboembolic complications in the form of periprocedural TIA and stroke. Hemorrhagic complication rates were similar.

The role of imaging for the detection of vascular lesions in patients with intracerebral hemorrhage (ICH) is poorly defined. A study was undertaken to compare the yield of digital subtraction angiography (DSA) in patients with ICH with intraventricular hemorrhage (IVH) and those without IVH.The DSA database at our institution was reviewed for patients who underwent DSA for acute spontaneous ICH over a period of 68 months. Patients with known vascular malformation or brain neoplasm, prior surgery, ischemic infarction, subarachnoid hemorrhage or isolated IVH were excluded. Patients were grouped into those with associated IVH (group A) and those without (group B). Baseline demographic and clinical data, non-contrast head CT (NCCT) probability for a vascular lesion and angiographic results were compared.293 patients met the inclusion and exclusion criteria (141 women, 152 men, mean age 57, range 18-88), 139 in group A and 154 in group B. Age and sex distributions were similar (p0.05). Group A patients were more likely to be hypertensive or coagulopathic (p=0.001). Group B had more patients with high probability NCCT scans (p0.001). Underlying vascular lesions were found in 21 patients (15.1%) in group A and 34 (22.1%) in group B (p0.05).The presence of IVH in patients with acute spontaneous ICH is not associated with an increased risk of an underlying vascular lesion and should not be used to select patients for neurovascular evaluation.

Background and purpose Variability in response to the P2Y12 receptor antagonists administered to patients with cerebral aneurysms treated with the Pipeline Embolization device (PED) or stents may play an important role in post-operative thromboembolic and haemorrhagic complications. We present our initial institutional experience using a target P2Y12 reaction units (PRU) range to tailor the clopidogrel dose administered. Methods We retrospectively reviewed all patients who underwent endovascular treatment of cerebral aneurysms with the PED or stent-assistance at our institution from November 15th, 2011 until December 31st, 2013. Patient characteristics, P2Y12 receptor antagonist administered, thromboembolic and haemorrhagic complications, and clinical outcomes using the modified Rankin Scale (mRS) were recorded. The target PRU range was 60–240. Results Sixty-six patients were included, 49 females (74%) and 17 males (26%), mean age 57.5 years (25–82 years). Forty-six patients were treated with the PED (70%), 19 with a stent (29%) and 1 with a PED and a stent (1%). Eight patients were switched to prasugrel due to an initial clopidogrel hypo-response (12.1%). Forty patients underwent at least 1 adjustment to the clopidogrel dose due to either a hypo-response (PRU > 240) or hyper-response (PRU Conclusion Overall, 73% of patients with cerebral aneurysms treated with the PED or stents required at least 1 adjustment to the clopidogrel dose or a switch to an alternate P2Y12 receptor antagonist to remain within the target 60–240 PRU range. Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3, Microvention/Terumo, Penumbra Inc. Y. Kadkhodayan: 2; C; Covidien/ev3. J. Scholz: None. J. Fease: None. A. Blem: None. K. Tran: None. B. Crandall: 2; C; Covidien/ev3.

Background Conventional treatment of stenosis at the common carotid artery origin has involved extra-anatomic bypass using an open cervical approach or median sternotomy. The goal of this study is to determine the procedural feasibility and safety of angioplasty and stenting at the common carotid origin as a less invasive alternative. Methods Between March 1996 and November 2005, a total of 248 carotid angioplasty and/or stenting procedures were performed at our institution. Of these, 8 procedures were performed in 7 patients for treatment of a stenosis or dissection located at the common carotid origin. There were 4 males and 3 females with a mean age of 58 (range, 22-77). Five patients presented with neurologic symptoms. The patients' medical records were retrospectively reviewed for imaging reports (cerebral angiography, computed tomography, or ultrasound) and available clinical follow-up. Brief telephone interviews with patients, immediate family, or care personnel were also used. Procedural and midterm complication rates were calculated. Results Of 8 procedures, 7 (87.5%) resulted in no residual stenosis. The procedural stroke rate was 0 (0%) of 8 procedures. The procedural TIA rate was 2 (25%) of 8 procedures. The mean follow-up was 31.7 months (range, 11.3-75.9 months). In 2 cases, follow-up was clinical only. In the remaining cases, there were clinical and imaging follow-up in the form of cerebral angiography (n = 3), CT angiography (n = 2), and ultrasound (n = 1). There was one recurrent TIA at 30 days and again at 3.1 months (1/8, 12.5%). There were no strokes (0/8, 0%) and there were no TIAs in patients who were initially asymptomatic on presentation. There was one death from an unrelated cause. Conclusion In this series, angioplasty and stenting were effective in relieving stenosis at the common carotid origin and have low rates of ischemic complications.

We read with great interest the letter from Dr Bruno Law-Ye Jr et al 1 commenting on our recent article on the use of flow diversion for treatment of three de novo fusiform aneurysms due to dilating HIV vasculopathy in an adult patient.2 As clearly stated in our manuscript, although this entity is most commonly seen in children, the natural history …

Recurrent carotid stenosis following endarterectomy is a common complication, and reoperation may be associated with increased morbidity. The goal of this study was to determine the procedural safety and long-term complication rates of carotid angioplasty and stenting for recurrent stenosis.Of 248 consecutive carotid angioplasty and/or stenting procedures performed at our institution between March 1996 and November 2005, 83 procedures for recurrent stenosis following endarterectomy were performed in 75 patients (mean age 68 years; 43 men, 32 women) without cerebral protection devices. The patients' medical records were retrospectively reviewed for vascular imaging reports and available clinical follow-up. Procedural and long-term complication rates were calculated.Recurrent stenosis was reduced from a mean of 80.6% to no significant stenosis in 82 of 83 procedures. The procedural stroke rate was 3 out of 83 procedures (3.6%). The procedural transient ischemic attack (TIA) rate was 2 out of 83 procedures (2.4%). Mean follow-up was 22.4 months (range 0.1 to 86.7 months) with at least 6 months follow-up for 54 of 83 procedures (65%). There were five TIAs and no strokes on follow-up (new TIAs at 25.5 and 43.4 months; recurrent TIAs at 1, 11.1, and 12 months, all with normal angiograms). The composite 30-day stroke, myocardial infarction, or death rate was 5 of 83 procedures (6.0%).In this series, angioplasty and stenting were effective in relieving stenosis secondary to recurrent carotid disease after endarterectomy, and have low rates of ischemic complications.

BACKGROUND AND PURPOSE: Carotid angioplasty and stent placement may be the preferred treatment in patients with carotid dissection who have failed medical management. The goal of this study was to determine the procedural feasibility and safety as well as long-term complication rates of carotid angioplasty and stent placement in a consecutive cohort of relatively young, high-surgical-risk patients. PATIENTS AND TECHNIQUES: A series of 26 consecutive patients (mean age, 49 years; 15 men and 11 women) who underwent angioplasty and stent placement for carotid dissection with or without pseudoaneurysm from April 1997 to April 2005 at our institution (9 traumatic, 8 spontaneous, and 9 iatrogenic) was retrospectively reviewed. Twenty-eight stents were used in 29 procedures performed on 27 vessels (20 internal carotid arteries and 7 common carotid arteries). Patients were followed with cerebral angiography, CT, sonography, or clinically for a mean of 14.6 months (range, 5 days to 48.2 months) with 17 of 26 patients having at least 6 months of follow-up. Procedural and long-term complication rates were calculated. RESULTS: Dissection-induced stenosis was reduced from 71 ± 18% to no significant stenosis in 20 of the 21 patients with measurable stenosis. The procedural transient ischemic attack (TIA) rate was 3 of 29 procedures (10.3%). There were no procedural strokes. One patient required angioplasty of a common femoral artery. One procedure was terminated when an asymptomatic new intimal flap was created before intervention. Two patients had occlusions of the treated vessel noted at 22 days (presented with contralateral stroke) and 3.4 months (asymptomatic). There were 2 unrelated deaths from myocardial infarction at 8 days and 15.2 months. Two patients had recurrent ipsilateral TIA at 2.7 months and 12 months. The 30-day occlusion and death rate was 2 of 29 procedures (6.9%). CONCLUSION: In this series, angioplasty and stent placement were effective in relieving stenosis secondary to carotid dissection with or without pseudoaneurysm and have low rates of ischemic complications.

Purpose To determine the medium-term clinical outcome in a cohort of patients presenting with aneurysmal subarachnoid haemorrhage (SAH) treated endovascularly within the framework of a multi-disciplinary neurovascular team at a tertiary referral medical centre over a 45-month period. Methods We conducted a retrospective review of all patients who presented to our institution with aneurysmal SAH and underwent endovascular treatment of the ruptured aneurysm within the framework of a multi-disciplinary neurovascular team from January 1st, 2009, until September 30th, 2012. Baseline clinical characteristics, surgical and endovascular interventions performed and discharge disposition were recorded. Clinical outcome at the time of last follow-up was assessed with the modified Rankin Scale (mRS). A good clinical outcome was defined as an mRS 0–2. Results One-hundred and twenty-four patients presented with aneurysmal SAH and underwent endovascular treatment of the ruptured aneurysm at our institution during the study period. Eighty-seven patients were female (70.2%) and 37 male (29.8%), with a mean age of 56.2 years (median 57 years, range 22–91 years). Sixty-eight patients required placement of an external ventricular drain (54.8%), 28 placement of a ventriculoperitoneal shunt (22.6%), and 6 a decompressive craniectomy (4.8%). Twenty-six patients required endovascular treatment of symptomatic cerebral vasospasm (21%), 85% of which were treated with balloon-angioplasty of the affected vessel (s) with or without an intra-arterial nicardipine infusion, and 15% were treated with an intra-arterial nicardipine infusion only. Mean Neuro-ICU length of stay was 14.3 days (median 14.5 days, range 1–39 days). Mean hospital length of stay was 19 days (median 18 days, range 1–39 days). Discharge disposition was home in 62 patients (50%), a rehabilitation facility in 39 patients (31.5%), a skilled nursing facility in 12 patients (9.7%), and 11 patients did not survive the hospitalisation (8.9%). Eight patients were lost to follow-up (6.5%). Mean time to last clinical follow-up for the 105 survivors with follow-up was 14.6 months (median 9.6 months, range 3.7–48 months). Overall, a good clinical outcome at the time of last clinical follow-up was observed in 83 patients (71.6%). The table summarises the clinical outcome at the time of last clinical follow-up according to admission Hunt-Hess scale in our patient cohort. Conclusion The majority (72%) of patients presenting with aneurysmal SAH who underwent endovascular treatment of the ruptured aneurysm within the framework of a multi-disciplinary neurovascular team at our institution demonstrated a good clinical outcome at the time of last clinical follow-up, including 41% of patients with an admission Hunt-Hess scale 4–5. Clinical Outcome at the Time of Last Clinical Follow-up in Patients with Aneurysmal SAH Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. Y. Kadkhodayan: None. B. Crandall: 2; C; Covidien/ev3. J. Scholz: None. R. Anderson: None. K. Lockhart: None. T. Mowbray-Donahue: None. K. Uittenbogaard: None. G. Dyste: None. J. Fease: None. D. Tubman: 2; C; Covidien/ev3, MicroVention.

Purpose To determine the variability in clopidogrel response and examine its relationship to perioperative thromboembolic and hemorrhagic complications in the initial cohort of patients treated with the Pipeline device at a tertiary medical center. Methods The Abstract O-035 table 1 summarizes the dual antiplatelet therapy regimens implemented in the first 6 and subsequent 15 patients in our cohort. All patients underwent P2Y12 inhibition testing with the VerifyNow test. P2Y12 inhibition target therapeutic range was 40–199 platelet reaction units (PRUs) or 40-89% inhibition. Variability in patient response to clopidogrel therapy was defined as follows: (1) Non-responder if PRUs >240 or Results 21 patients were included in our study, 17 females (81%) and four males (19%). Mean patient age was 59.7 years (median 63 years, range 31–81 years). In the initial pre-treatment P2Y12 inhibition test, three patients were non-responders to clopidogrel therapy (14.3%), two patients were poor responders to clopidogrel therapy (9.5%), and two patients were hyper-responders to clopidogrel therapy (9.5%). In the post-treatment P2Y12 inhibition test, two patients who had initially been within the target therapeutic range became hyper-responders to clopidogrel therapy (9.5%, both symptomatic). Three patients experienced perioperative thromboembolic complications (14.3%, two cerebral infarctions and one transient ischemic attack), which resolved without a new permanent neurological deficit in two patients and caused a new permanent neurological deficit leading to moderate disability in one patient (4.8%). One patient experienced a perioperative hemorrhagic complication consisting of a frontal intracerebral hemorrhage ipsilateral to the Pipeline device (4.8%), which resolved without a new permanent neurological deficit. Two of the three patients (66.7%) who experienced thromboembolic complications had been poor responders to clopidogrel therapy in the initial P2Y12 inhibition test. The patient who experienced the hemorrhagic complication had become a hyper-responder to clopidogrel therapy after the initial P2Y12 inhibition test. There was a strong trend toward fewer perioperative complications in the second group of patients (6.7%) compared to the first (50%, p value 0.053). Conclusion We found significant and dynamic variability in patient response to clopidogrel therapy in our initial cohort of patients treated with the Pipeline device, with 43% of patients falling outside the P2Y12 inhibition target therapeutic range in the perioperative period. This variability in patient response to clopidogrel therapy appears to be directly related to the perioperative thromboembolic and hemorrhagic complications in our cohort. Adopting a protocol with early initiation of dual antiplatelet therapy, rigorous pre and post-procedure P2Y12 inhibition testing, and active management of patients who fall outside the target therapeutic range may minimize the risk of perioperative thromboembolic and hemorrhagic complications in patients treated with the Pipeline device. Competing interests J Delgado Almandoz: None. B Crandall: Covidien/ev3. J Scholz: None. J Fease: None. Y Kadkhodayan: None. R Anderson: None. D Tubman: Covidien/ev3.

Introduction A variable response to clopidogrel among patients undergoing neurointerventional procedures has been observed. To minimise thromboembolic and haemorrhagic complications, patients premedicated with clopidogrel in anticipation of elective endovascular intracranial aneurysm treatment at our institution are asked to start clopidogrel 75 mg daily, 17 days prior to their procedure date, with pre-procedure P2Y12 inhibition testing using the VerifyNow assay performed at 10 and 17 days, as well as post-procedure testing for patients treated with stents or flow-diverters. The protocol allows for a single dose adjustment after the first test in order to achieve pre-procedure P2Y12 reaction units (PRU) in a target range without rescheduling. The goal of the present study is to determine the efficacy of this protocol in reaching an in-range pre-procedure PRU and to determine the rate of delayed clopidogrel hyper-response post-procedure. Methods All patients who were started on clopidogrel using the above 17 day, 2 test protocol in anticipation of elective endovascular treatment of an intracranial aneurysm at our institution from April 30, 2013 to March 6, 2014 were included. Patient age, sex, procedural variables and PRU values were recorded. Hyper-response to clopidogrel was defined as PRU less than 60; hypo-response was defined as PRU greater than 240. Results Forty patients met the inclusion criteria, mean age 55 (range 35 to 79), 33 women, 7 men. Of these patients, 29 (72.5%) had a PRU value between 60 and 240 at 10 days, and 27 of the 29 (93.1%) stayed within range at 17 days. Of the 11 patients (27.5%) who were initially out of range and had a dose adjustment per the tables below, 10 (90.9%) reached an in-range PRU at day 17, for a total of 37 patients (92.5%) with an in-range pre-procedure PRU. A post-procedure PRU was performed in 28 of the 37 patients (75.7%, mean 14 days post-procedure). Among these, 14 (50%) showed a delayed hyper-response to clopidogrel, and there was 1 delayed hypo-responder (3.6%), leaving 13 patients (46.4%) who remained in-range post-procedure. There were no major peri-procedural thromboembolic or haemorrhagic neurological complications in patients following this protocol. Conclusion The protocol described to reach a pre-procedure PRU within a target range limited the rate of rescheduled procedures to 7.5%. Nevertheless, half of the patients who were in-range pre-procedure exhibited a hyper-response to clopidogrel in post-procedure VerifyNow testing. This apparently induced hyper-response to clopidogrel may be related to a post-procedural change in hepatic clopidogrel metabolism. Disclosures Y. Kadkhodayan: 2; C; Covidien. J. Delgado Almandoz: 2; C; Covidien, MicroVention, Penumbra. J. Scholz: None. J. Fease: None. A. Blem: None. K. Tran: None. B. Crandall: 2; C; Covidien.

Purpose To determine the frequency and predictors of post-procedural diffusion-weighted-imaging (DWI) abnormalities in patients with cerebral aneurysms treated with the Pipeline Embolization Device (PED). Methods Two interventional neuroradiologists reviewed post-procedural MRI examinations performed in patients with cerebral aneurysms treated with the PED at our institution to determine the number of DWI abnormalities present in the vascular territory of the treated aneurysm. Baseline patient and aneurysm characteristics and procedural variables were recorded. Results Twenty-two patients were included, 15 female (68%) and 7 male (32%), mean age 53.2 years (25–79 years). Mean aneurysm size 11.2 mm (2.5–22 mm), mean neck size 6.5 mm (1.6–17 mm), 5 aneurysms were fusiform (22.7%). Mean pre-procedure P2Y12 reaction units (PRU) value was 164.9 (81–275). PEDs were deployed in the internal carotid artery (ICA) in 16 patients (72.8%), middle cerebral artery in 3 patients (13.6%) and vertebral artery in 3 patients (13.6%). Mean procedure time was 86 min (median 75 min, range 39–189 min). Mean number of PEDs deployed was 1.2. At the time of post-procedural MRI, 4 patients exhibited focal neurological deficits (18%, mean 3.5 days post-procedure) and 18 were asymptomatic (82%, all on post-operative day [POD] 1). At least 1 DWI abnormality was observed in 17 patients (77%), including all 4 symptomatic (100%) and 13 asymptomatic patients (72%). Mean number of DWI abnormalities was 12.5 (median 4, range 0–70), with a trend towards a higher number in symptomatic patients (mean 26.8, range 5–70) than in asymptomatic patients (mean 9.3, range 0–48, p-value 0.1). Eleven patients had a high DWI burden, defined as ≥5 DWI abnormalities (50%). Predictors of a high DWI burden were fusiform aneurysm morphology (100%, p-value 0.035), female sex (67%, p-value 0.06), and procedure time >90 min (70%, p-value 0.09). Conclusion We observed a high rate of asymptomatic ipsilateral DWI abnormalities after PED procedures (72%). The combination of a high DWI burden and P2Y12-receptor over-inhibition post-procedure may play an important role in the aetiology of delayed ipsilateral ICHs encountered after PED procedures. Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. Y. Kadkhodayan: 2; C; Covidien/ev3. J. Fease: None. J. Scholz: None. A. Blem: None. K. Tran: None. B. Crandall: 2; C; Covidien/ev3.

Background and purpose Recent studies have examined the variability in response to clopidogrel therapy in patients undergoing endovascular treatment of unruptured cerebral aneurysms; however, no study has systematically assessed patient response to aspirin therapy in this patient population. This study aims to determine the initial response to aspirin therapy in patients undergoing endovascular treatment of unruptured cerebral aneurysms. Methods We retrospectively reviewed the results of platelet function testing in a cohort of patients who were started on aspirin therapy for the endovascular treatment of unruptured cerebral aneurysms at our institution from November 17th, 2011 until March 13th, 2014. Baseline patient characteristics, aspirin dosing and thromboembolic complications were recorded. Patient response to aspirin therapy was assessed with the PFA-100 assay before the procedure, with ≥50% inhibition defined as an appropriate platelet response. Results One-hundred and seventeen patients were included in the study, 23 male (20%) and 94 female (80%), mean age 56 years (25–84 years). The patients included in this cohort comprised 52.5% of patients who underwent treatment of an unruptured cerebral aneurysm at our institution during the study period. Forty-eight patients were active smokers (41%), 72 had a history of hypertension (62%) and 6 diabetes mellitus (5%). Sixty-two patients were treated with simple or balloon-assisted coiling (53%), 43 with the Pipeline Embolization Device (37%) and 12 with a stent (10%). Fifty-three patients were started on 325 mg aspirin (45%), 50 on 81mg enteric-coated aspirin (43%), and 14 on 81 mg non-enteric-coated aspirin (12%). Mean number of aspirin doses before the initial PFA-100 test was 11.5 (median 9, range 3–29). Overall, mean initial platelet inhibition was 68.2% (median 70.5%, range 20.5–94.6%), with a significantly-lower mean inhibition in patients taking 81mg enteric-coated aspirin (62.5%) compared to those taking 81 mg non-enteric-coated aspirin (72.1%, p-value 0.049) and 325 mg aspirin (72.5%, p-value 0.001). Overall, 13 patients were considered to be non-responders to aspirin therapy in the initial PFA-100 test (11.1%), most of whom were taking 81mg enteric-coated aspirin (9, 69%). There was a significantly-increased likelihood of an initial non-response to aspirin therapy among patients taking 81 mg enteric-coated aspirin (18%) compared to those taking 81 mg non-enteric-coated aspirin (7.1%) and 325 mg aspirin (5.7%, p-value 0.04). In multivariate logistic regression analysis, an 81 mg enteric-coated aspirin dose was the only independent predictor of an initial non-response to aspirin therapy in our cohort (odds ratio 0.52, 95% confidence interval 0.28–0.98, p-value 0.043). There were 7 thromboembolic complications in our cohort (6%), none of which caused a permanent disabling neurological deficit or death. All of the patients who experienced a thromboembolic complication had demonstrated an appropriate platelet response to aspirin therapy in pre-procedure testing. Conclusion Performing pre-procedure platelet function testing in patients taking 81 mg enteric-coated aspirin to ensure an adequate platelet response to aspirin therapy may be prudent prior to undertaking endovascular treatment of an unruptured cerebral aneurysm. Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3, Microvention/Terumo. Y. Kadkhodayan: 2; C; Covidien/ev3. J. Scholz: None. J. Fease: None. A. Blem: None. K. Tran: None. B. Crandall: 2; C; Covidien/ev3.

Background and purpose The Sceptre XC balloon is a novel extra-compliant dual-lumen balloon microcatheter designed for the endovascular treatment of cerebral aneurysms and arteriovenous malformations. This study aims to describe our initial institutional experience with the Sceptre XC balloon for the treatment of cerebral aneurysms. Methods We performed a retrospective review of endovascular treatments of cerebral aneurysms with the Sceptre XC balloon at our institution from April 11th, 2012 until February 28th, 2014. Baseline patient and aneurysm characteristics, procedural variables, packing density, intra- operative and post-operative complications, and clinical outcomes using the modified Rankin Scale (mRS) were recorded. Results Forty-five patients underwent endovascular treatment of 54 cerebral aneurysms with assistance of the Sceptre XC balloon at our institution during the study period, 33 females (73%) and 12 males (27%), mean age 58.5 years (28–87 years). Fifty-three aneurysms were treated successfully (98.1%). Forty-two aneurysms were unruptured (78%) and 12 ruptured (22%); 5 aneurysms were recurrent (9%). Mean aneurysm size was 7 mm (median 6.3 mm, range 2–17 mm), mean neck size was 3.2 mm (median 2.8 mm, range 1–8.2 mm), mean dome-to-neck ratio was 1.8 (median 1.5, range 0.8–6.5). Aneurysm locations were 17 middle cerebral artery (32%), 13 anterior communicating artery (24%), 13 internal carotid artery (24%), 5 posterior communicating artery (9%), 2 pericallosal artery (4%) and 4 posterior circulation (7%). Balloon neck remodeling was performed in 49 aneurysms (91%), and stent-assistance was ultimately used in 3 aneurysms (5.6%). Three aneurysms were coiled directly through the Sceptre XC balloon (5.6%). Mean packing density was 39.4% (median 40%, range 12–72.2%). Immediate complete/near complete occlusion was achieved in 34 aneurysms (64%), residual neck in 7 aneurysms (13%) and residual sac in 12 aneurysms (23%). The table summarises the intra-operative and post-operative complications in our cohort. There were 3 intra-operative aneurysm ruptures (5.6%), 2 of previously-ruptured aneurysms (16.7%) and 1 of an unruptured aneurysm (2.4%), hemostasis was achieved by immediate balloon inflation in all cases and no patient developed a new neurological deficit. There was 1 distal branch vessel rupture during balloon inflation performed to reduce an intra-aneurysmal catheter loop for a wire exchange prior to stenting, resulting in the patient’s death (2.2%). There was 1 ipsilateral intracerebral haemorrhage on post-operative day 2 in a hypertensive patient with a clopidogrel hyper-response leading to permanent contralateral hemiparesis (2.2%). Overall, 2 complications led to either a new permanent disabling neurological deficit or the patient’s death (mRS ≥ 3, 4.4%). Conclusion The Sceptre XC balloon is a valuable adjunctive device for the endovascular treatment of cerebral aneurysms, allowing high treatment success rates and packing densities, achievement of immediate hemostasis in the event of an intra-operative aneurysm rupture, and reduction in the overall need of stent-assistance for cerebral aneurysm treatment. Disclosures J. Delgado Almandoz: 2; C; Microvention/Terumo, Covidien/ev3, Penumbra Inc. Y. Kadkhodayan: 2; C; Covidien/ev3. J. Fease: None. J. Scholz: None. A. Blem: None. K. Tran: None. B. Crandall: 2; C; Covidien/ev3.

A 58-year-old woman presented with a palpable mass at the base of the left neck which she had first noticed 12 years previously, shortly after abdominal surgery. The mass had progressively enlarged, resulting in dysphagia, dyspnea and occasional pain. Imaging showed a septated but otherwise simple cystic mass extending into the mediastinum and containing lymphocytic fluid on aspiration. A diagnosis of the rare entity of a thoracic duct cyst with supraclavicular extension was made. The patient opted for percutaneous sclerotherapy of the lesion, which was performed using glacial acetic acid. This resulted in complete resolution of the mass with one treatment. After exclusion of other causes of cystic left supraclavicular masses including cystic neoplasms and pseudoaneurysms of the carotid or subclavian arteries, direct puncture sclerotherapy can be safe and effective.

Purpose To determine if the Alberta Stroke Program Early CT Score (ASPECTS) applied to non-contrast CT (NCCT) and CT angiography source images (CTA-SI) predicts clinical outcome in a cohort of patients with an acute middle cerebral artery (MCA) occlusion undergoing mechanical thrombectomy with stent-retrievers. Methods We conducted a retrospective review of patients who presented to our institution with an acute MCA occlusion and underwent mechanical thrombectomy with a stent-retriever from March 31st, 2012 until February 21st, 2013. Baseline clinical and procedural characteristics were recorded. Two experienced neurointerventionalists applied the ASPECTS to the pre-treatment NCCT and CTA-SI (if performed), with differences resolved by consensus. A “good scan” was defined as one with an ASPECTS ≥5. Clinical outcome at the time of hospital discharge or last clinical follow-up was determined utilising the modified Rankin Scale (mRS), with a good clinical outcome defined as an mRS of 0–2. Results Thirty patients presented to our institution with an acute MCA occlusion and underwent mechanical thrombectomy with a stent-retriever during the study period. Fifteen patients were female (50%) and 15 male (50%), with a mean age of 67.2 years (median 69 years, range 33–86 years). Mean admission NIHSS was 15.8 (median 16, range 5–27). Sixteen patients (53.3%) had received iv-tPA prior to endovascular treatment. Twenty-five patients (83.3%) had an MCA M1 segment occlusion and in 5 patients (16.7%) the occlusion extended to the internal carotid artery terminus. Mean time from NCCT to arterial puncture was 117 minutes (median 109 minutes, range 39–307 minutes). Mean time from CTA to arterial puncture was 104 minutes (median 92 minutes, range 16–272 minutes). Successful recanalisation (TICI 2b/3) was achieved in 26 patients (86.7%). Mean time from arterial puncture to successful recanalisation was 47 minutes (median 37 minutes, range 18–115 minutes). Mean time from symptom onset to successful recanalisation was 333 minutes (median 285 minutes, range 125–893 minutes). All pre-treatment NCCTs were categorised as “good scans”, with perfect inter-observer agreement. Twenty patients had a pre-treatment CTA performed (66.7%), 11 of which were categorised as “good scans” (55%), with substantial inter-observer agreement (kappa 0.8). Overall, a good clinical outcome was observed in 11 patients (36.7%), with a statistically-significant difference between the 12 patients age ≤65 years (66.7%) and the 18 patients age >65 years (16.7%, p-value 0.009). The table summarises the frequency of a good clinical outcome according to age group and pre-treatment CTA-SI ASPECTS. Conclusion In our cohort of patients with acute MCA occlusion undergoing mechanical thrombectomy with stent-retrievers, a “good scan” NCCT (ASPECTS ≥5) predicted a 67% likelihood of a good clinical outcome in patients age ≤65 years, while a “good scan” CTA (ASPECTS ≥5) predicted a 43% likelihood of a good clinical outcome in patients age >65 years. Clinical Outcome after Mechanical Thrombectomy with Stent-Retrievers by Age and CTA-SI ASPECTS. Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. Y. Kadkhodayan: None. M. Young: None. B. Crandall: 2; C; Covidien/ev3. R. Tarrel: None. J. Fease: None. J. Scholz: None. R. Anderson: None. T. Hehr: None. K. Gozel: None. R. Shronts: None. D. Tubman: 2; C; Covidien/ev3.

Background and Purpose Recent studies have suggested that variability in response to clopidogrel therapy may explain some of the thromboembolic and hemorrhagic complications encountered after endovascular treatment of cerebral aneurysms with flow-diversion or stent-assistance. This study aims to determine the variability in response to a 75mg daily clopidogrel dose measured with VerifyNow in a cohort of patients undergoing endovascular treatment of unruptured cerebral aneurysms. Methods We performed a retrospective review of all patients who were started on a daily 75mg clopidogrel dose 7 to 10 days prior to endovascular treatment of a cerebral aneurysm and had the response to clopidogrel therapy measured with VerifyNow prior to the procedure over a 15-month period. Baseline clinical characteristics, concurrent medications and routine pre-operative laboratory values were collected. Changes in response to the daily 75mg clopidogrel dose in patients who underwent follow-up VerifyNow testing were also recorded. The target P2Y12 receptor inhibition range was 60–240 P2Y12 reaction units (PRU), with a PRU>240 considered a hypo-response to clopidogrel therapy (P2Y12 receptor under-inhibition), and a PRU Results Ninety patients were included in the study, 66 female (73.3%) and 24 male (26.7%). Mean age was 57.4 years (median 59.9 years, range 25–82 years). Mean pre-procedure PRU value after 6–9 75mg clopidogrel doses was 140.1 (median 143 PRU, range 3–399 PRU). Eighteen patients exhibited a hyper-response to clopidogrel therapy (20%, PRU 240, figure). There was a trend toward an increased likelihood of a hyper-response to clopidogrel therapy among female patients (24.2%) compared to male patients (8.3%, p-value 0.14). Overall, 39.4% of female patients and 25% of male patients were outside the target P2Y12 receptor inhibition range in pre-procedure VerifyNow testing. Follow-up VerifyNow testing was performed in 32 patients (35.6%), which revealed that 33.3% of patients who had initially been within the target PRU range exhibited a “conversion” to a hyper-response to a daily 75mg clopidogrel dose (mean 15.2 PRU, median 8 PRU, range 1–59 PRU). We found no increased likelihood of P2Y12 receptor over-inhibition in patients on a selective serotonin reuptake inhibitor (18.8%), or P2Y12 receptor under-inhibition in patients on a proton pump inhibitor (9.1%). Conclusion We found wide variability in patient response after 6–9 daily 75mg clopidogrel doses, with 20% of patients exhibiting P2Y12 receptor over-inhibition (PRU>60) and 16% of patients exhibiting P2Y12 receptor under-inhibition (PRU>240). Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. Y. Kadkhodayan: None. J. Scholz: None. B. Crandall: 2; C; Covidien/ev3. J. Fease: None. R. Anderson: None. D. Tubman: 2; C; Covidien/ev3, MicroVention.

Background and Purpose A recent study identified a pre-procedure P2Y12 reaction units (PRU) value 240 as a strong independent predictor of perioperative thromboembolic and haemorrhagic complications occurring up to 30 days after treatment of cerebral aneurysms with the Pipeline Embolisation Device (PED). This study aims to determine if a last-recorded PRU value 240 predicts thromboembolic and haemorrhagic complications occurring up to 6 months after treatment of cerebral aneurysms with the PED in the same patient cohort. Methods We recorded patient and aneurysm characteristics, P2Y12 receptor antagonist administered, PRU value with VerifyNow, procedural variables, number of P2Y12 receptor antagonist dose adjustments, and thromboembolic and haemorrhagic complications occurring up to 6 months after PED procedures at our institution during an 8-month period. Complications causing a permanent disabling neurological deficit or death were considered major. Multivariate regression analysis was performed to identify independent predictors of thromboembolic and haemorrhagic complications. Target P2Y12 receptor inhibition range was initially 80–200 PRU and was subsequently expanded to 60–240 PRU. Results Forty-four patients underwent 48 PED procedures at our institution during the study period. There were 11 thromboembolic and haemorrhagic complications occurring up to 6 months after treatment in our cohort (22.9%), 5 of which were major (10.4%). Among the 5 major complications, 4 occurred in the perioperative period and 1 occurred on post-operative day 50 (ICH with subdural extension contralateral to the PED in a patient with autopsy-proven amyloid angiopathy). Four of the 5 major complications occurred in patients who exhibited markedly elevated (292) or decreased (0, 10, 58) PRU values shortly before or at the time of the complication. A last-recorded PRU value 240 was the only independent predictor of all (p-value 0.002) and major (p-value 0.03) thromboembolic and haemorrhagic complications in our cohort (Table). Most patients (71%) required, on average, 2 adjustments to the dose or type of P2Y12 receptor antagonist administered to remain within the 60–240 target PRU range. Conclusion In our cohort, a last-recorded PRU value was the only independent predictor of all and major thromboembolic and haemorrhagic complications up to 6 months after PED procedures. Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. B. Crandall: 2; C; Covidien/ev3. J. Fease: None. J. Scholz: None. R. Anderson: None. Y. Kadkhodayan: None. D. Tubman: 2; C; Covidien/ev3, MicroVention.

Introduction The endovascular treatment of middle cerebral artery (MCA) aneurysms has been controversial due to the frequency of complex anatomy and relative ease of surgical clipping in this location. We present the largest reported single-centre experience in the endovascular treatment of MCA aneurysms. Methods The neurointerventional database at our institution was reviewed for all endovascular treatments of MCA aneurysms through August 2012. Patient demographics, aneurysm characteristics, treatment modality, intraprocedural haemorrhagic and thromboembolic events (any occurrence of intraprocedural thrombus or embolus), 30-day periprocedural neurological events and follow-up angiographic studies were recorded. Results From December 1996 to August 2012, 281 patients underwent 331 attempted endovascular procedures for treatment of an MCA aneurysm. Of these, 326 procedures were completed (5 attempted and failed). 217 procedures used balloon assistance. 85 were primary coilings. 4 were with the Pipeline device. 25 were with stent assistance. 17 were retreatments. 92 were for ruptured aneurysms. Mean aneurysm size was 6.6 mm. The rate of intraprocedural aneurysm rupture or vessel perforation was 2.7% (9 of 331). 2 resulted in disabling strokes (mRS>2 at discharge) in patients with unruptured aneurysms, comprising the only patients with new disabling strokes with unruptured aneurysms in the entire cohort (0.6%, 2 of 331). The rate of intraprocedural thromboembolic events was 13.9% (46 of 331), mostly in patients with acute subarachnoid haemorrhage (SAH, p 2 at discharge. In patients without intraprocedural thromboembolic events, there were no disabling strokes in patients with unruptured aneurysms. There were an additional 3 TIA’s (1 with SAH) and 6 non-disabling strokes (1 with SAH) within 30 days. There was one non-disabling delayed parenchymal haemorrhage (IPH) in a patient who underwent stent-assisted coiling of an unruptured aneurysm. There were 3 strokes in the setting of SAH with confounding severe vasospasm; 2 of these were disabling. The rate of angiographic occlusion or near occlusion at 6 months or greater follow-up was 76.2% (214 out of 281). Conclusion Endovascular treatment of MCA aneurysms is associated with a high intraprocedural thromboembolic event rate, though mostly asymptomatic and in the setting of acute SAH. Almost all periprocedural strokes were confounded by severe vasospasm or a large Sylvian clot with surrounding oedema. In the absence of these factors, endovascular treatment of MCA aneurysms is safe and effective with current technology, and indications for endovascular treatment of this subgroup will likely continue to expand as newer devices become available. Disclosures Y. Kadkhodayan: None. J. Delgado Almandoz: 2; C; Covidien. J. Fease: None. J. Scholz: None. R. Anderson: None. B. Crandall: 2; C; Covidien. D. Tubman: 2; C; Covidien, Microvention.

Dilating HIV vasculopathy can be a cause of ischemic and hemorrhagic stroke in patients with HIV. Although first identified in children, this condition is increasingly being recognized in adults and has a dismal natural history under medical or expectant management. Vessel wall invasion by varicella zoster virus, HIV or Mycobacterium avium intracellulare complex (MAI) has been postulated as a possible etiology. We present a case of an adult patient with HIV and chronic disseminated MAI infection who presented with ischemic stroke and three fusiform cerebral aneurysms that were successfully treated with the pipeline embolization device (PED). Flow diversion may be a viable treatment option for patients presenting with this serious neurovascular condition when aneurysm location precludes parent vessel sacrifice or surgical bypass. In addition, platelet function testing with VerifyNow may be valuable in selecting the appropriate P2Y12 receptor antagonist to be used in order to prevent PED thrombosis, since some of the antiretroviral drugs may inhibit clopidogrel or prasugrel metabolism.

An attempt at parent vessel reconstruction with Pipeline embolization devices to treat a mycotic pseudoaneurysm of the internal carotid artery at the skull base is presented. A 50-year-old woman with malignant otitis externa and bilateral temporal bone osteomyelitis presented with brisk bleeding from her left ear. She had bony dehiscence of the left carotid canal at CT and extravasation from a pseudoaneurysm of the carotid petrous segment at angiography. Carotid tortuosity proximally precluded placing a covered stent. After the lesion stopped bleeding spontaneously and given the presence of bilateral osteomyelitis putting the contralateral carotid at risk, the decision was made to attempt preservation of the parent vessel with flow diversion. However, bleeding recurred after 12 days, necessitating carotid sacrifice. This first reported experience in treating a carotid pseudoaneurysm at the skull base with the Pipeline device shows that transient cessation of bleeding is insufficient for flow diversion to be effective.

Purpose Intracranial arterial stenosis is one cause of ischemic stroke. A two-step procedure using one specific angioplasty balloon (Gateway®) and one specific self-expanding stent (Wingspan®) was inferior to best medical management in a recent trial (SAMMPRIS), partly due to a greater than expected complication rate in its interventional arm. There are other devices that can be used to dilate stenotic cerebral arteries in a one-step approach. If complications are fewer and long-term results are favorable, treatment by dilation with such devices may achieve superiority over best medical management in patients who are medically refractory. Drug-eluting balloon-mounted stents (DES) can be deployed in a one-stage procedure in stenotic intracranial arteries and are less prone to re-stenosis than bare-metal stents, though there is some concern about late in-stent thrombosis. Long-term outcomes of intracranial DES treatment have not been previously studied. We report the long-term follow-up of 10 patients treated with DES for symptomatic intracranial arterial stenosis refractory to medical management. Methods From 2003 to 2007, 10 patients (mean age, 58.9 years) with intracranial arterial stenosis that remained symptomatic (recurrent TIA or stroke) despite medical therapy were treated with DES. Twelve Cipher balloon-expandable stents were deployed, with 2 of the 10 patients receiving two stents each due to the presence of multiple high-grade lesions. Four lesions required pre-dilation with balloon angioplasty using the Maverick® system. Medical records were reviewed for demographic information, procedural details, complications, and follow-up imaging results. Telephone interviews were performed in August, 2011, to assess for new stroke or TIA, disability according to the modified Rankin Scale (mRS), and compliance with anti-platelet medications. Results Stenotic lesions were located in the internal carotid artery in six patients, the middle cerebral artery in one patient, the vertebral artery in two patients, and both a vertebral artery and the basilar artery in one patient. All 12 stents were successfully deployed. A mean stenosis of 81.5±13.3% was reduced to 7.1±16.3%. In 1 patient with 99% stenosis of the left ICA, the lesion could not be reduced to Conclusion The safety and long-term efficacy of DES in preventing recurrent stroke in symptomatic patients with high-grade intracranial arterial stenosis who are refractory to medical management is promising and should encourage further study of that intervention for that patient subgroup. Competing interests R Gottumukkala: None. Y Kadkhodayan: None. A Mazumdar: None. C Moran: EV3, Stryker, Codman. C Derdeyn: W.L Gore and Associates. nFocus, Pulse therapeutics. D Cross: None.

Purpose To assess the size and location of ruptured intracranial aneurysms in patients presenting with first-time acute subarachnoid hemorrhage (SAH) treated endovascularly at a tertiary referral medical center over a 16-year period. Methods We retrospectively reviewed the size and location of ruptured intracranial aneurysms in all patients presenting to our institution with first-time acute SAH who underwent endovascular treatment from June 1, 1995 until January 31, 2012. The aneurysm location and maximum sac dimension were recorded utilizing catheter angiography. In patients with multiple aneurysms, we recorded data for the aneurysm thought most likely to be responsible for the SAH based on SAH distribution, maximum aneurysm sac dimension and sac morphology. Results A total of 1681 intracranial aneurysms underwent endovascular treatment at our institution during the study9s 16-year time period. Of these, 613 (36.5%) ruptured aneurysms were treated emergently in 588 patients with first-time acute SAH (393 females and 195 males, mean age 54.9 years, range 7–97 years). In 22 patients (3.7%), two or more intracranial aneurysms were treated emergently due to the inability to definitely identify the causative aneurysm. The most common ruptured aneurysm locations were anterior communicating (36.5%), posterior communicating (19.6%), middle cerebral (13.5%), internal carotid (11.4%) and basilar (7.8%) arteries (Abstract O-008 table 1). Overall mean ruptured aneurysm maximum sac dimension was 6.5 mm (range 1.3–30 mm, median 5.7 mm), 6.5 mm for anterior circulation aneurysms (range 1.7–30 mm, median 5.3 mm) and 6.4 mm for posterior circulation aneurysms including the posterior communicating artery (range 1.3–27 mm, median 6 mm). In our series, 373 (60.8%) of the ruptured intracranial aneurysms had a maximum sac dimension Conclusion The majority (61%) of ruptured intracranial aneurysms treated endovascularly for first-time acute SAH at our institution had a maximum sac dimension Competing interests None.