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Background The Scepter XC is a dual-lumen balloon catheter that accommodates a 0.014-inch microwire and can be used for balloon-assisted coiling of cerebral aneurysms. We describe our experience with the use of this device. Methods Two high-volume institution neurointerventional databases were retrospectively reviewed for cerebral aneurysms treated with balloon-assisted coiling using the Scepter XC balloon catheter. Patient demographics, aneurysm characteristics, and procedural details were recorded. Major procedure-related neurologic complications were defined as events that caused an increase in modified Rankin Scale that persisted for more than 1 week after the procedure. Follow-up aneurysm occlusion was assessed using the Raymond-Roy classification. Results During the study period, 231 aneurysms were treated in 219 patients (152 women, 67 men) with a mean age of 58.4 ± 12.2 years. Mean aneurysm size was 6.1 ± 3.1 mm, with a mean neck diameter of 3.1 ± 1.3 mm. In total, 77.5% of aneurysms were wide necked, and 39.8% were treated in the setting of subarachnoid hemorrhage. The major complication rate was 0.9% (2/231) per treated aneurysm, including one stroke and one death related to intraoperative aneurysm rupture. Excluding patients who died, angiographic follow up was available for 85.3% (191/224) of aneurysms. During a mean follow up of 17.4 ± 13.0 months (range, 1.7–66.5 months), Raymond-Roy 1 and 2 occlusion rates were 56.5% (108/191) and 35.6% (68/191), respectively. The retreatment rate was 12.6% (24/191). Conclusion Our experience using the coaxial dual-lumen Scepter XC for balloon-assisted coiling demonstrates acceptable aneurysm occlusion and complication rates.

Background The Pipeline embolization device (PED) has expanded the range of aneurysms amenable to endovascular treatment, including some that were previously untreatable. The PED contains several metals, including nickel, cobalt, chromium, platinum, and tungsten. The safety of PED implantation in patients with cutaneous metal allergy is unknown. The aim of this study was to assess clinical and angiographic outcomes of PED treatment in patients with cutaneous metal allergy. Methods A single-institution neurointerventional database was retrospectively reviewed for patients with documented cutaneous metal allergy who were treated with the PED. Patient, aneurysm, and procedural data were collected, including perioperative and delayed complications. Posttreatment angiograms were reviewed for in-Pipeline stenosis and aneurysm occlusion. Results Twenty patients with metal allergy underwent 23 PED treatments for 26 aneurysms. The cohort was 95% (19/20) female; mean age was 55.7 years. Aneurysms were primarily anterior circulation (92%, 24/26) and saccular (92%; 24/26); mean size was 8.8 mm (range, 2–32 mm). One PED was implanted in 70% (14/20) of patients, 25% (5/20) had 2 devices placed, and 1 patient had 3 devices. One major procedural complication occurred (4.3%, 1/23) in which a stroke was caused by perioperative PED thrombosis. Angiographic follow-up was available for all patients (mean duration 15.7 months; range, 6–64 months), which demonstrated a complete aneurysm occlusion rate of 88% (23/26). Asymptomatic in-Pipeline stenosis occurred in 2 cases, resulting in 65% and 50% parent artery stenosis, respectively. Conclusions Preliminary results suggest that PED implantation in patients with cutaneous metal allergy is safe and effective.

The Scepter XC balloon catheter can be used for balloon-assisted coiling (BAC) of cerebral aneurysms but also accommodates delivery of a low-profile visible intraluminal stent (LVIS Jr.). We assessed the safety and effectiveness of BAC using the Scepter XC, with LVIS Jr. stent-assisted coiling (SAC) as a bailout option.A single-institution prospectively maintained neurointerventional database was reviewed for wide-necked (neck width ≥4 mm or dome/neck ratio2) saccular aneurysms treated using the Scepter XC. Complication and angiographic occlusion rates of BAC and SAC procedures were compared. Multivariate logistic regression was used to identify variables predictive of complete aneurysm occlusion.The cohort included 141 wide-necked saccular intracranial aneurysms treated in 135 procedures. SAC was used to treat 30% of aneurysms by deploying the LVIS Jr. through the Scepter XC. The overall procedural complication rate was 8.9%, including a 1.5% rate of symptomatic thromboembolic events and 3.0% rate of hemorrhagic complications, with no significant differences in complications between BAC and SAC procedures (P = 0.27). The overall complete or near-complete aneurysm occlusion rate was 96%, with trends toward higher complete aneurysm occlusion and lower retreatment rates with SAC (78 vs. 57%; P = 0.13; 0 vs. 8.4%, P = 0.13). Multivariate logistic regression identified aneurysm size, procedure technique (BAC or SAC), and duration of follow-up as independent predictors of complete aneurysm occlusion.Use of the Scepter XC for BAC, with LVIS Jr. SAC as a bailout option, shows acceptable angiographic and clinical results.

PurposeTo report the efficacy of A Direct Aspiration first-Pass Thrombectomy (ADAPT) technique with larger-bore ACE aspiration catheters as first-line treatment for anterior circulation emergent large vessel occlusions (ELVOs), and assess for the presence of a first-pass effect with ADAPT.MethodsWe retrospectively reviewed 152 consecutive patients with anterior circulation ELVOs treated with the ADAPT technique as first-line treatment using ACE60, 64, or 68 at our institution. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded.ResultsFifty-seven patients were treated with ACE60 (37.5%), 35 with ACE64 (23%), and 60 with ACE68 (39.5%). Median groin puncture to reperfusion time was 30 min with ACE60, 26 min with ACE64, and 19.5 min with ACE68. Successful reperfusion after the first ADAPT pass was 33% with ACE60 and 53% with ACE68 (P=0.04). The stent-retriever rescue rate was 26% with ACE60, 3% with ACE64, and 10% with ACE68 (P=0.004). In multivariate logistic regression analysis, use of the ACE68 aspiration catheter was an independent predictor of successful reperfusion after the first ADAPT pass (P=0.016, OR1.67, 95% CI 1.1 to 2.54), and successful reperfusion after the first ADAPT pass was an independent predictor of good clinical outcome at 90 days (P=0.0004, OR6.2, 95% CI 2.27 to 16.8).ConclusionUse of the larger-bore ACE 68 aspiration catheter was associated with shorter groin puncture to reperfusion time, higher rate of successful reperfusion after the first ADAPT pass, and lower rate of stent-retriever rescue. Further, a first-pass effect was demonstrated in our ADAPT patient cohort.

IntroductionVariable response to clopidogrel can impact perioperative risk in elective endovascular intracranial aneurysm treatment. The present study aims to determine the efficacy of a two-test protocol in reaching in-range preoperative P2Y12 reaction units (PRU) of 60–240 and the rate of postoperative conversion to hyper-response.MethodsA 17-day two-test protocol (with tests on days 10 and 17) for patients starting clopidogrel in anticipation of elective endovascular intracranial aneurysm treatment was introduced in February 2013 at our institution. Records for patients started on this protocol through December 2014 were reviewed for preoperative and postoperative PRUs, patient and procedural data, and thromboembolic and hemorrhagic events within 30 days. Logistic regression analyses were performed to identify predictors of postoperative hyper-response (pResults103 patients (80 women) of mean age 57 years were included. 74 patients (71.8%) were in range at the first test and 92 patients (89.3%) were in range at the second test. A postoperative test was performed in 82 patients (79.6%) at a median of 9 days. 51 patients (62.2%) converted into hyper-responders. There were five non-disabling strokes and one intracranial hemorrhage within 30 days. There were no major strokes (modified Rankin Scale score >2) or deaths. There was no association between out-of-range PRU and thromboembolic or hemorrhagic neurological complications.ConclusionsThe protocol achieves in-range preoperative PRU by the second test in almost nine of 10 patients. Nearly two-thirds of patients exhibited postoperative hyper-response to clopidogrel. Out-of-range PRU was not associated with thromboembolic or hemorrhagic neurological complications in this cohort of patients with actively managed P2Y12 inhibition.

Delayed ipsilateral intraparenchymal hemorrhage (IPH) has been reported following technically successful treatment of intracranial aneurysms using flow-diverting stents in up to 8.5 % of patients. We report a similar, though less frequent phenomenon in the setting of stent-assisted coil embolization. Institutional review board approval was obtained. A retrospective analysis of a prospective neurointerventional procedure registry was performed to review all IPHs that occurred in aneurysm patients within 90 days of endovascular treatment performed between November 2002 and November 2014 at one institution. Age, sex, hypertension, dual antiplatelet therapy, and technical details of the procedure were recorded. A total of 1697 patients underwent endovascular treatment of an intracranial aneurysm without a flow diverter at our institution during the study period. Among these, 138 patients underwent stent-assisted coiling (8.1 %). Of these, three patients (2.2 %) suffered a delayed IPH within the vascular territory distal to the treated lesion (one woman, median age 60 years). Recently described in the setting of flow diversion, delayed ipsilateral IPH is not limited to flow-diverting stents. Though less frequent, a potential for this complication may exist following any intracranial stenting procedure, possibly related to hemorrhagic conversion of microembolic phenomena in the setting of dual antiplatelet or anticoagulation therapy.

Background The Scepter XC balloon catheter can be used for balloon-assisted coiling (BAC) of cerebral aneurysms, but also accommodates delivery of a low profile visible intraluminal stent (LVIS Jr.). We assessed the safety and effectiveness of BAC using the Scepter XC, with LVIS Jr. stent-assisted coiling (SAC) as a bailout option. Methods A single-institution prospectively-maintained neurointerventional database was retrospectively reviewed for wide-necked (neck width ≥4 mm or dome-to-neck ratio Results The cohort included 169 wide-necked saccular intracranial aneurysms treated in 157 procedures. SAC was used to treat 25% of aneurysms by deploying the LVIS Jr through the Scepter XC. The overall procedural complication rate was 11%, including 3.2% rates of symptomatic thromboembolic and hemorrhagic complications, with no significant differences in complications between BAC and SAC procedures (p=0.26). The overall complete aneurysm occlusion rate was 59%, with trends toward higher complete aneurysm occlusion and lower retreatment rates with SAC (78 vs 54%, p=0.07; 0 vs 9.3%, p=0.10). Multivariate logistic regression identified aneurysm size, procedure technique (BAC or SAC), and duration of follow up as independent predictors of complete aneurysm occlusion. Conclusions Initial experience using the Scepter XC for BAC, with LVIS Jr. SAC as a bailout option, demonstrates acceptable angiographic and clinical results. Disclosures A. Wallace: None. Y. Kayan: 2; C; Medtronic, Penumbra, Microvention. J. Delgado Almandoz: 2; C; Medtronic, Penumbra, Microvention, Accriva. J. Fease: None. A. Milner: None. J. Scholz: None. M. Thomas: None.

Purpose To determine the correlation of serum S100B protein levels with clinical outcome and the presence of DWI abnormalities in acute subarachnoid hemorrhage (SAH). Methods Patients with diffuse SAH at our institution were offered enrollment in a prospective study in which serial MRI, including DWI, FLAIR, PWI, and ASL sequences, was performed at admission, 7 days, 30 days, and upon the development of signs/symptoms of vasospasm. As well, serum S100B levels were measured at the time of each MRI. Patient demographics, Hunt-Hess grade, modified Fisher score, and underlying lesion and treatment technique were recorded. Poor clinical outcome was defined as mRS 3–6 at discharge. Mean S100B levels were compared using Student’s t-test. ROC analyses were performed using MedCalc v18.2.1. p Results Between November 2013 and August 2017, 50 patients were enrolled, 37 women, mean age 58, 20 current smokers. Hunt-Hess grade mean was 3.0. Modified Fisher score mean was 3.5. All underlying vascular lesions were treated endovascularly: 17 ACA aneurysms, 14 ICA aneurysms (including PCOM), 10 MCA aneurysms, 3 basilar tip aneurysms, 1 vertebral aneurysm, 1 posterior fossa AVM, and 4 angiographically-negative SAHs. Mean serum S100B was 73.4 ng/L, 55.1 ng/L and 57.8 ng/L on admission, at 7 days and 30 days, respectively. Overall, serum S100B was significantly higher on admission than at 7 days (p=0.01). Admission serum S100B was significantly higher in patients with poor outcome at discharge (p=0.0003) and in patients with any DWI abnormalities on admission (p=0.0004). The correlation of elevated serum S100B with the presence of DWI abnormalities persisted at 7 days (60.7 ng/L versus 42.8 ng/L, p=0.007). ROC analyses revealed a cutoff of admission S100B>69 ng/L resulting in a sensitivity of 54.8% and a specificity of 94.7% for poor outcome at discharge with an AUC of 0.74 (95% CI 0.60–0.85, p=0.0005), and a cutoff of admission S100B>61 ng/L resulting in a sensitivity of 64.5% and a specificity of 82.4% for the presence of any DWI abnormalities on admission with an AUC of 0.75 (95% CI 0.61–0.86, p=0.0004). Conclusion Admission S100B levels were elevated in setting of acute subarachnoid hemorrhage. Higher S100B levels were associated with poor outcomes at discharge and the presence of DWI abnormalities, both on admission and at 7 days. Disclosures Y. Kayan: 2; C; Medtronic, Penumbra. J. Delgado Almandoz: 2; C; Medtronic, MicroVention, Penumbra. J. Fease: None. A. Wallace: None. J. Scholz: None. A. Milner: None. N. Banerji: None. M. Mulder: None.

Purpose To determine the natural history of diffusion weighted imaging (DWI) abnormalities in early acute subarachnoid hemorrhage (SAH). Methods Patients with diffuse SAH at our institution were offered enrollment in a prospective study in which serial MRI, including DWI, FLAIR, PWI, and ASL sequences, was performed at admission, 7 days, 30 days, and upon the development of signs/symptoms of vasospasm. Patient demographics, Hunt-Hess grade, modified Fisher score, and underlying lesion and treatment technique were recorded. Results Between November 2013 and August 2017, 50 patients were enrolled, 37 women, mean age 58, 20 current smokers. Hunt-Hess grade mean was 3.0. Modified Fisher score mean was 3.5. All underlying vascular lesions were treated endovascularly: 17 ACA aneurysms, 14 ICA aneurysms (including PCOM), 10 MCA aneurysms, 3 basilar tip aneurysms, 1 vertebral aneurysm, 1 posterior fossa AVM, and 4 angiographically-negative SAHs. 31 patients (62%) had DWI abnormalities on their admission scan; all had undergone a catheter angiogram or endovascular treatment of the underlying lesion prior to the MRI. The total number of DWI abnormalities amongst these patients was 250 (214 At 7 days, the total number of DWI abnormalities was 267 (224 Conclusion The acquisition of additional multifocal ischemic injury to the brain is common in early SAH. This phenomenon is independent of cerebral perfusion and large-vessel vasospasm. Disclosures Y. Kayan: 2; C; Medtronic, Penumbra. J. Delgado Almandoz: 2; C; Medtronic, MicroVention, Penumbra. J. Fease: None. A. Wallace: None. J. Scholz: None. A. Milner: None. N. Banerji: None. M. Mulder: None.

Purpose To determine recanalization and post-treatment rupture rates in a large cohort of patients with intracranial aneurysms treated with simple or balloon-assisted coil embolization. Methods We retrospectively reviewed consecutive patients with intracranial aneurysms treated with simple or balloon-assisted coil embolization at our institution from August 8th, 1995 to September 30th, 2017. Baseline aneurysm and patient characteristics, procedural variables and angiographic outcomes were recorded. Aneurysm recanalization was defined as Raymond 3 or Raymond 2 with a neck remnant ≥4 mm or ≥33% of initial aneurysm volume. Multivariate regression analysis was performed to identify independent variables associated with aneurysm recanalization. Results 1634 patients with 1935 intracranial aneurysms were included, 1196 women (73%), mean age 56 years (median 56 years, 8–97 years). 1125 aneurysms were incidental (58.1%), 752 ruptured (38.9%) and 58 symptomatic (3%). Mean aneurysm size 6.3 mm (median 5.5 mm, 1.6–27.9 mm), mean neck 3 mm (median 2.8 mm, 0.6–16.2 mm), mean dome-to-neck ratio 1.7 (median 1.5, 0.7–6.5). Aneurysm locations: 502 ICA (25.9%), 461 Acomm (23.8%), 375 MCA (19.4%), 276 Pcomm (14.3%), 128 basilar tip (6.6%), 79 other ACA (4.1%) and 114 other posterior circulation (5.9%). 749 aneurysms were treated with simple coiling (38.7%) and 1186 with balloon-assisted coiling (61.3%), mean packing density 33.4% (median 31.5%, 6.5%–94.9%). Angiographic follow-up was completed in 1574 of 1730 aneurysms available (91%), mean time to last follow-up 5.3 years (median 4.4 years, 0–20.5 years). Aneurysm occlusion at last follow-up was Raymond 1 in 878 aneurysms (55.8%), Raymond 2 in 496 aneurysms (31.5%), and Raymond 3 in 200 aneurysms (12.7%). There were 254 aneurysm recanalizations at last follow-up (16.1%), and 202 aneurysms were retreated (12.8%). Table 1 summarizes independent predictors of aneurysm recanalization in our cohort. Table 2 summarizes recanalization rates by location and rupture status. 13 aneurysms ruptured after coiling (0.8%), corresponding to an annual post-treatment rupture rate of 0.15%. Mean time from treatment to rupture was 5.8 years (median 4.5 years, 0–12.7 years). Mean time from last angiographic evaluation to rupture was 2.2 years (median 1 year, 0–10.2 years). Aneurysm occlusion at the last angiographic evaluation prior to rupture was Raymond 1 in 4 aneurysms, Raymond 2 in 3 aneurysms, and Raymond 3 in 6 aneurysms. 12 post-treatment ruptures occurred in aneurysms treated before 1/1/2008. Conclusion Endovascular aneurysm treatment with coils alone is associated with relatively high long-term recanalization and post-treatment rupture rates, especially after treatment of ruptured aneurysms. Long-term angiographic follow-up and early retreatment of recanalized aneurysms would be prudent. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Microvention/Terumo, Penumbra, Inc. Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra, Inc. A. Wallace: None. J. Fease: None. J. Scholz: None. A. Milner: None. M. Mulder: None.

Introduction Balloon-assisted coiling (BAC) is a well-established technique for treatment of wide-necked cerebral aneurysms. The Scepter XC (Microvention, Tustin, California, USA) is a dual-lumen balloon catheter that can be used for aneurysm-neck remodeling, protection of branch vessels arising from or near the aneurysm neck, and stabilization of the microcatheter during coil deployment. The lumen also accommodates a 0.014 inch microwire. We describe our initial experience with the use of this device for BAC of cerebral aneurysms. Methods Two high-volume institution neurointerventional databases were retrospectively reviewed for cerebral aneurysms treated with BAC using the Scepter XC balloon catheter. Wide-neck aneurysms were defined as those with a neck width ≥4 mm or a dome-to-neck ratio 10 mm, or DSA and rated using the Raymond-Roy classification. Results During the study period, 231 aneurysms were treated in 219 patients (152 women, 67 men) with a mean age of 58.4±12.2 years. Mean aneurysm size was 6.1±3.1 mm, with a mean neck diameter of 3.1±1.3 mm. 77.9% (180/231) of aneurysms were wide-necked, and 39.8% (92/231) were acutely ruptured at the time of treatment. The overall complication rate was 12.1% (28/231) per treated aneurysm, including a 4.8% (11/231) rate of symptomatic thromboembolic events, 8.6% (8/92) rate of intraoperative rupture when treating acutely ruptured aneurysms, and 1.4% (2/139) rate of intraoperative aneurysm rupture in elective cases. Excluding patients who died, DSA or MRA follow up was available for 85.3% (191/224) of aneurysms. During a mean follow-up of 17.4±13.0 months (range, 1.7–66.5 months), Raymond-Roy 1oc and 2oc clusion rates were 56.5% (108/191) and 35.6% (68/191), respectively. The retreatment rate was 13% (24/191). Conclusions Balloon-assisted coiling using the dual coaxial lumen Scepter XC demonstrates acceptable aneurysm occlusion and complication rates. Disclosures A. Wallace: None. E. Samaniego: 2; C; Medtronic, Microvention. Y. Kayan: 2; C; Medtronic, Penumbra, Microvention. C. Derdeyn: None. J. Delgado: 2; C; Medtronic, Penumbra, Microvention, Accriva. B. Zheng: None. J. Fease: None. M. Thomas: None. J. Scholz: None. A. Milner:None. S. Ortega: 2; C; Stryker Neurovascular, Medtronic.

Purpose To report the efficacy of A Direct Aspiration first-Pass Thrombectomy (ADAPT) technique with evolving ACE aspiration catheter technology as first-line treatment for anterior circulation emergent large vessel occlusions (ELVOs) and assess for the presence of a first pass effect with ADAPT. Methods We retrospectively reviewed 152 consecutive patients with anterior circulation ELVOs treated with the ADAPT technique as first-line treatment using ACE 60, 64 or 68 at our institution. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded. Results Fifty-seven patients were treated with ACE 60 (37.5%), 35 with ACE 64 (23%) and 60 with ACE 68 (39.5%). Median groin puncture to reperfusion time was 30 min with ACE 60, 26 min with ACE 64, and 19.5 min with ACE 68. Successful reperfusion after the first ADAPT pass was 33% with ACE 60% and 53% with ACE 68 (p=0.04). Of note, successful reperfusion after the first ADAPT pass was achieved in 23 of 33 patients with M1 occlusions treated with ACE 68 in our cohort (69.7%). The stent-retriever rescue rate was 26% with ACE 60, 3% with ACE 64% and 10% with ACE 68 (p=0.004). The rate of embolus to a new territory was 5.3% with ACE 60, 2.9% with ACE 64% and 1.7% with ACE 68 (p=0.5). The rate of intracranial vascular injury was 1.8% with ACE 60, 5.7% with ACE 64% and 5% with ACE 68 (p=0.5). The symptomatic intracranial hemorrhage rate was 1.8% with ACE 60, 5.7% with ACE 64% and 6.7% with ACE 68 (p=0.4). At 90 days, a good clinical outcome, mRS 0–2, was achieved in 70 patients (46.1%), while 27 patients had mRS 3 (17.8%), 22 mRS 4–5 (14.5%), and 33 expired (21.7%). In multivariate logistic regression analysis, use of the ACE 68 aspiration catheter was an independent predictor of successful reperfusion after the first ADAPT pass (p-value 0.016, OR 1.67, 95% CI 1.1–2.54), while successful reperfusion after the first ADAPT pass was an independent predictor of good clinical outcome at 90 days (p-value 0.0004, OR 6.2, 95% CI 2.27–16.8). Conclusion Use of the ACE 68 aspiration catheter was associated with shorter groin puncture to reperfusion times, higher rates of successful reperfusion after the first ADAPT pass, and lower rates of stent-retriever rescue. Further, a first pass effect was demonstrated in our ADAPT patient cohort. Disclosures J. Delgado Almandoz: 2; C; Penumbra, Inc. Y. Kayan: 2; C; Penumbra, Inc. A. Wallace: None. R. Tarrel: None. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. M. Mulder: None. M. Young: None.

Purpose To evaluate the safety and efficacy of the Low-profile Visualized Intraluminal Support (LVIS) Jr stent for treatment of intracranial aneurysms. Methods We conducted a retrospective review of all consecutive patients with intracranial aneurysms treated with the LVIS Jr stent between June 4th, 2014 and March 31 st, 2018 at our institution. Baseline patient and aneurysm characteristics, procedural variables, complications and aneurysm occlusion at follow-up were recorded. Results 81 patients underwent 91 procedures to treat 95 intracranial aneurysms using the LVIS Jr stent, 59 women (73%), mean age 59.1 years (median 60 years, 32–83 years). 42 aneurysms were incidental (44%), 41 recurrent (43%), 9 ruptured (10%), and 3 symptomatic (3%). Mean aneurysm size was 6.3 mm (median 5.2 mm, 1.5–31.3 mm), mean neck 3.8 mm (median 2.9 mm, 0.9–13.7 mm), mean dome-to-neck ratio 1.4 (median 1.3, 0.6–2.7). Aneurysm locations were: 36 anterior communicating artery, 26 middle cerebral artery (MCA), 12 basilar tip, 10 anterior cerebral artery, 4 internal carotid artery, 2 posterior communicating artery, 2 vertebral artery and 1 each posterior inferior cerebellar, superior cerebellar and posterior cerebral arteries. Aneurysm embolization techniques were: 91 stent-assisted coiling (96%) and 4 flow diversion (4%). Y-stenting was used for 13 aneurysms (14%), T-stenting for 2 aneurysms (2%) and X-stenting for 1 aneurysm (1%). The LVIS Jr was deployed via a Scepter XC balloon in 49 procedures (54%). Mean packing density was 40% (median 38.5%, 8.8%–90.9%), mean procedure time was 83 min (median 74 min, 35–201 min). The table summarizes treatment-related complications in our cohort. There were no intra-procedural aneurysm/vessel perforations. There were 4 treatment-related complications resulting in a disabling neurological deficit or death (modified Rankin Scale>2, 4.4%). These were 1 MCA perforator infarction on post-operative day (POD) 0; 1 subacute T-stent thrombosis on POD 4; 1 rectus sheath hematoma after percutaneous feeding tube placement leading to severe anemia, hypotension and left MCA territorial infarction on POD 21 in a patient with a ruptured aneurysm; and 1 delayed basilar artery perforator infarction 7 months after Y-stenting of a recurrent giant basilar tip aneurysm. Treatment-related mortality was 2.5%, overall neurological mortality 6.2%. Angiographic follow-up was performed in 58 aneurysms (66%, 30 aneurysms pending follow-up). Follow-up was completed with MR angiography in 54 aneurysms (93%) and catheter angiography in 4 aneurysms (7%). Mean time to last follow-up was 14.1 months (median 6.5 months, 2.9–38.4 months). At last follow-up, 41 aneurysms were completely occluded (70.7%, Raymond 1), 12 had residual neck (20.7%, Raymond 2) and 5 had residual aneurysm (8.6%, Raymond 3). 5 aneurysms were retreated (8.6%). Conclusion The LVIS Jr stent is a safe and effective tool for the treatment of intracranial aneurysms, achieving high medium-term complete/near complete aneurysm occlusion rates with low treatment-related morbidity and mortality and low re-treatment rates. Disclosures J. Delgado Almandoz: 2; C; Microvention/Terumo. Y. Kayan: None. A. Wallace: None. J. Scholz: None. A. Milner: None. J. Fease: None. M. Mulder: None.

Introduction The Pipeline Embolization Device (PED; Medtronic Neurovascular, Irvine, CA) has expanded the spectrum of aneurysms amenable to endovascular treatment. The device is a braided mesh cylinder composed of 48 strands of 25% platinum and 75% cobalt-nickel alloy. An estimated 17% of women and 3% of men are allergic to nickel, and the safety PED implantation in these patients is a concern. The purpose of this study was to assess the clinical and angiographic outcomes of PED treatment in patients with nickel allergy. Methods A single institution neurointerventional database was retrospectively reviewed for patients treated with the PED who had a documented nickel allergy. In some patients patch testing was performed preoperatively, consisting of taping a PED to the patient’s skin for 1 week. Patient demographics, aneurysm characteristics, and procedural details were recorded. All patients received dual antiplatelet therapy for approximately 17 days before treatment, and response was assessed with VerifyNow (Accriva Diagnostics; San Diego, CA). Follow-up digital subtraction angiography was performed 6 months post procedure. Longer-term follow up was performed with CT angiography when PED alone was used or MRA with and without contrast when adjunctive coiling was performed. Follow-up functional status was graded using the modified Rankin Scale (mRS). Good clinical outcome was defined as mRS ≤2 at last clinical follow up. Results During the study period, 22 patients with documented nickel contact dermatitis underwent 23 PED treatments for 29 aneurysms. Patch testing was performed in 55% (12/22) of patients, none of whom experienced a skin reaction. The cohort included 21 women and 1 man with a mean age of 53.6±14 years. Patient medical comorbidities were as follows: hypertension, 40.9%; hyperlipidemia, 9.1%; type 2 diabetes mellitus, 0%. 36% (8/22) of patients actively smoked at the time of treatment. Mean aneurysm size was 8.8±8.1 mm (range, 2.0–32.0 mm), with 93% (27/29) located in the anterior circulation and 7% (2/29) in the posterior circulation. No aneurysms were treated in the setting of subarachnoid hemorrhage. Most patients were treated with a single PED (79.3%, 23/29). Five patients were treated with two PEDs and one was treated with three PEDs. 28% (8/29) of aneurysms were treated with adjunctive coiling. 18% (4/22) of patients experienced a symptomatic complication, all of which were thromboembolic, but all patients (100%, 22/22) had a good clinical outcome. During a mean angiographic follow-up of 16.2±13.0 months (range, 3–64 months), complete and near-complete (>90%) occlusion rates were 77% (20/26) and 4% (1/26), respectively. Endothelial hyperplasia occurred in one case (3%), which resulted in approximately 65% asymptomatic parent artery stenosis. Conclusion All patients with nickel allergy treated with the PED had a good clinical outcome, but the thromboembolic complication rate was higher than typically reported for PED series. Further research is needed to determine if nickel allergy is an independent risk factor for procedural complications. Disclosures A. Wallace: None. J. Delagado Almandoz: 2; C; Medtronic, Penumbra, Accriva, Microvention. Y. Kayan: 2; C; Medtronic, Penumbra, Microvention. J. Fease: None. M. Thomas: None. J. Scholz: None. A. Milner: None.

Introduction Larger bore reperfusion catheters have been designed to increase the effectiveness of direct aspiration for treatment of acute ischemic stroke due to large vessel occlusions. The present study has two goals: 1. To compare the reperfusion rate of the newest large bore reperfusion catheter, ACE68, with previous generations of ACE catheters, ACE64 and ACE60, and 2. To compare the cost associated with three first-line approaches to mechanical thrombectomy: ADAPT using evolving ACE technology, Solumbra, and stent-retriever (SR) with balloon-guide catheter (BGC). Methods The prospectively populated acute stroke intervention database at our institution was retrospectively reviewed for mechanical thrombectomies performed using the ADAPT technique as a first-line approach from July 2013 through February 2017. Successful reperfusion (defined as TICI 2b/3) rates amongst the successive generations of ACE reperfusion catheters were compared. The costs of the procedures were also compared, including the costs of salvage therapy using adjunctive devices when necessary (additional reperfusion catheters or SR). These costs were then compared to the costs of hypothetically performing these procedures using Solumbra or SR as first-line approaches. List prices for devices were used in the cost comparison. The two-tailed Fisher’s exact test was used for the reperfusion rate comparisons, and Student’s t-test was used for the cost comparisons with p Results Between July 2013 and February 2017, 131 ADAPT cases were performed using ACE reperfusion catheters. There were 42 cases using the ACE68 as first-line, with a successful reperfusion rate using aspiration alone of 90% (38 of 42). This was significantly higher than with previous generations of ACE as first-line, where the rate of successful reperfusion was 73% using aspiration alone (65 of 89 cases, p=0.02). The rate of successful reperfusion with a single aspiration pass was higher with ACE68 compared to previous generations (50% versus 37%) but this difference was not statistically significant (p=0.19). Overall successful reperfusion was similar when SR was used as salvage therapy (95% with ACE68 as first-line versus 85% with previous ACE generations, p=0.14). Out of 131 patients, 15% (n=20) required the use of SR after aspiration alone, with an improvement to TICI 2b/3 in 13 patients (65%). For ADAPT cases with salvage therapy included, the average device cost per case was not significantly different comparing previous ACE devices with ACE68: $6669 and $6,650, respectively. An ADAPT approach with any ACE catheter including the cost of salvage therapy resulted in significant cost savings compared to having hypothetically performed these procedures using Solumbra or SR as first-line with costs per case of $12,440 and $10,195, respectively, not including salvage therapy. Total costs for all patients for ADAPT, SR, and Solumbra were $866,150, $1,325,350, and $1,617,200, respectively. Conclusion ADAPT with the ACE68 reperfusion catheter resulted in a significantly higher rate of successful reperfusion using aspiration alone (90%) compared to previous generation ACE catheters. ADAPT also resulted in significant cost savings compared to Solumbra or SR first-line approaches. Disclosures Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra. J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Penumbra. M. Young: None. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. M. Mulder: None. A. Wallace: None. R. Tarrel: None.

Purpose This study9s goal is to evaluate the safety and efficacy of the Axium Prime Extra Soft (ES) coil for treatment of intracranial aneurysms. Methods We conducted a retrospective review of all consecutive patients with intracranial aneurysms treated with Axium Prime ES coils at a single center between January 26th, 2016 and March 28th, 2017. Baseline patient and aneurysm characteristics, procedural variables and complications were recorded. Aneurysm occlusion at angiographic follow-up was determined using the Roy-Raymond scale. Aneurysm retreatment was recorded. Results 45 patients with 48 intracranial aneurysms were included, 36 women (80%). Mean age was 58.2 years (median 58 years, 36–92 years). 47 aneurysms were treated successfully with coils (98%). 17 aneurysms were ruptured (35%), 8 recurrent (17%) and 3 symptomatic (6%). Mean maximum aneurysm size was 5.7mm (median 5.2mm, 2.2-26.2mm), mean neck 2.8mm (median 2.6mm, 1-6.2mm), mean dome to neck ratio 1.7 (median 1.4, 0.9-11.5). Aneurysm locations were: 13 anterior communicating artery, 11 middle cerebral artery, 10 internal carotid artery, 5 anterior cerebral artery, 4 posterior communicating artery, 1 basilar tip, and 1 each posterior inferior cerebellar, superior cerebellar, posterior cerebral and persistent hypoglossal arteries. Aneurysm embolization techniques were: 23 balloon-assisted coiling (48%), 11 stent-assisted coiling (23%), 10 simple coiling (21%), 3 Pipeline/coiling (6%), and 1 aneurysm was treated with flow diversion after attempted coiling (2%). Mean total number of coils deployed per aneurysm was 3.5mm (median 3, 1-14). Mean number of Axium Prime ES coils deployed per aneurysm was 2.1mm (median 2, 1-7). Mean Axium Prime ES coil length as total coil length percentage was 55.1% (median 42%, 11.1-100%). Mean packing density was 35.2% (median 35.7%, 1.6-63%). There were 6 peri-procedural complications: 3 coil herniations during balloon-assisted coiling requiring stenting (6%), 1 intra-operative aneurysm re-rupture controlled with balloon inflation (2%), 1 small peripheral subarachnoid hemorrhage on post-operative day 1 (2%), and 1 subacute stent thrombosis on post-operative day 4 (2%). The subacute stent thrombosis resulted in the patient’s death (2.2%). No other treatment-related complication resulted in a permanent neurological deficit or death. Overall mortality was 4.4%. Angiographic follow-up was performed in 19 aneurysms (42%, 26 aneurysms currently pending follow-up). Follow-up was completed with MR angiography in 17 aneurysms (90%) and catheter angiography in 2 aneurysms (10%). Mean time to follow-up was 6.3 months (median 6.1 months, 5.9-7.6 months). At follow-up, 14 aneurysms were completely occluded (74%, Raymond 1) and 5 showed residual neck (26%, Raymond 2). There were no residual aneurysms at follow-up (Raymond 3). No aneurysms were retreated. Conclusion The Axium Prime ES coil is safe and effective for the treatment of intracranial aneurysms, achieving high packing densities, low risk of major treatment-related complications, high medium-term complete/near-complete aneurysm occlusion rates, and low re-treatment rates. Disclosures: J. Delgado Almandoz: 2; C; Medtronic Neurovascular. Y. Kayan: 2; C; Medtronic Neurovascular. J. Scholz: None. A. Milner: None. A. Wallace: None. J. Fease: None. M. Mulder: None.

Purpose To examine clinical and angiographic outcomes in a cohort of consecutive patients with posterior circulation intracranial aneurysms treated with the Pipeline Embolization Device (PED) at a referral center. Methods We conducted a retrospective review of all patients with posterior circulation intracranial aneurysms treated with the PED in our center between January 23 rd , 2012 and January 24 th , 2017. Baseline patient and aneurysm characteristics, intra-­operative, peri-­operative and delayed complications were recorded. Aneurysm volumes in initial and follow-­up angiographic studies were calculated using AngioCalc. Clinical outcomes were categorized using the modified Rankin Scale (mRS). Results 17 patients underwent 18 PED procedures to treat 19 posterior circulation intracranial aneurysms during the study period. 12 patients were women (71%) and 5 men (29%). Mean age was 60 years (range 13-­80 years). 16 patients were premedicated with aspirin/clopidogrel with VerifyNow testing (94%), and 1 with aspirin/ticagrelor without VerifyNow testing (6%). 8 aneurysms were incidental (42%), 5 symptomatic (26%, 2 from mass effect), 4 recurrent (21%) and 3 ruptured (16%). 6 aneurysms were fusiform (32%), 3 dissecting (16%) and 2 blister (11%). 7 aneurysms were located in the basilar trunk (37%), 4 in the posterior inferior cerebellar artery (21%), 2 in the superior cerebellar artery (10.5%), 2 in the posterior cerebral artery (10.5%), 2 in the vertebral artery (10.5%), 1 in the basilar tip (5%) and 1 in a basilar perforator artery (5%). Mean aneurysm size was 8.8mm (1.7-34mm), mean neck was 6.7mm (0.6-32.6mm), mean dome-­to-­neck ratio was 1.3 (0.2-2.9). 12 aneurysms were wide-neck (≥4mm, 63%). Mean number of PEDs deployed per aneurysm was 1.3. Adjunctive coiling was performed in 4 aneurysms (21%). There were 2 intra-operative (11%), 3 peri-operative (17%) and 1 delayed (5.6%) complications, none led to a disabling neurological deficit (mRS≥3). There was no treatment-related mortality. There were no post-­operative aneurysm ruptures. Overall mortality was 5.9%. Angiographic follow-­up was available in 15 aneurysms (79%, 3 follow-ups currently pending), with a mean time to last angiographic follow-­up of 23.7 months (median 11 months, range 3.3-61.3 months). At last follow­-up, 11 aneurysms were completely occluded (73%), 3 aneurysms had incomplete occlusion (20%, mean 59.2% volume reduction), and 1 aneurysm had volume increase (7%, 166% increase). The enlarging aneurysm was re-treated with parent artery sacrifice (7%). Conclusion The PED is a safe and effective treatment for wide-neck posterior circulation intracranial aneurysms, with high long-term complete aneurysm occlusion rates, low re-­treatment rates, and a low rate of major treatment-related complications. Disclosures: J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Accriva Diagnostics. Y. Kayan: 2; C; Medtronic Neurovascular. J. Scholz: None. K. Uittenbogaard: None. A. Milner: None. J. Fease: None. A. Wallace: None. K. Nelson: None. M. Mulder: None.

Purpose To evaluate the effectiveness of the Penumbra system with ACE reperfusion catheters only (ACE only) versus ACE followed by Solitaire stent-retriever rescue (Solumbra rescue) for the treatment of anterior circulation emergent large vessel occlusions (ELVOs). Methods We performed a single center, retrospective review of 100 consecutive patients with anterior circulation ELVOs treated with ACE as first-line therapy. If successful revascularization (TICI 2b-3) was not achieved with ACE only, then Solumbra rescue was utilized. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded. Results 84 patients were treated with ACE only and 16 patients required Solumbra rescue. 53 patients received iv-tPA prior to mechanical thrombectomy. Overall successful revascularization for all 100 consecutive patients was 90%, with puncture to reperfusion time of 38.7 min, embolization to new territory rate of 5%, and post-procedure symptomatic intracranial hemorrhage rate of 3% (2 subarachnoid, 1 intraparenchymal). Successful revascularization using ACE only was achieved in 78 patients (38 after a single pass), while 12 of the 16 patients requiring Solumbra rescue were successfully revascularized (75%). Puncture to reperfusion time for ACE only versus Solumbra rescue were 30.5 and 81.8 min, respectively (p Conclusion Aspiration thrombectomy using the Penumbra system with ACE reperfusion catheters is an effective first-line treatment for anterior circulation ELVOs, with the option to use adjunctive stent-retriever devices if aspiration alone is not sufficient. Advancements in reperfusion catheter technology from ACE 60 to ACE 68 have resulted in shorter procedural times and reduced need for adjunctive stent-retriever device use. Disclosures J. Delgado Almandoz: 2; C; Penumbra, Inc, Medtronic Neurovacular. Y. Kayan: 2; C; Penumbra, Inc, Medtronic Neurovacular. M. Young: None. J. Scholz: None. A. Milner: None. J. Fease: None. P. Roohani: None. A. Wallace: None. M. Mulder: None. R. Tarrel: None.

Purpose The Penumbra Coil 400 System (PC400) was designed with increased coil diameter to enhance filling efficiency in large intracranial aneurysms. This study9s goal is to evaluate the safety and efficacy of the PC400 coils to treat large intracranial aneurysms. Methods We conducted a retrospective review of all consecutive patients with intracranial aneurysms treated with PC400 coils at a single center. Baseline patient and aneurysm characteristics, procedural variables and treatment-related complications were recorded. Aneurysm occlusion at the time of last angiographic follow-up was determined using the Roy-Raymond scale. Aneurysm retreatment was recorded. Results 57 consecutive patients with 60 intracranial aneurysms were included, 44 women (77%). Mean age was 60.7 years (median 60 years, 28–89 years). 12 aneurysms were ruptured (20%). Mean maximum aneurysm size was 12mm (median 10.5mm, 5.2-22mm), mean neck size was 5mm (median 4.1mm, 1.9-15mm), mean dome to neck ratio was 2 (median 1.9, 0.8-4.2). Aneurysm locations were: 27 internal carotid artery, 10 middle cerebral artery, 8 posterior communicating artery, 6 basilar tip, 5 anterior communicating artery, and 1 each posterior inferior cerebellar, superior cerebellar, posterior cerebral and anterior cerebral arteries. Aneurysm embolization techniques were: 30 balloon-assisted coiling (50%), 18 simple coiling (30%), 8 Pipeline/coiling (13%), 3 stent-assisted coiling (5%), and 1 parent artery sacrifice (2%). 49 aneurysms were treated with PC400 coils only (82%). Mean number of PC400 coils deployed was 5.1 (median 4, 1-23), mean packing density was 34% (median 33.5%, 7-68%). Mean procedure time was 64 minutes (median 53 minutes, 23–186 minutes). There were 6 peri-procedural complications: 2 intra-operative aneurysm ruptures (3.3%), 1 coil herniation requiring stenting (1.7%), and 3 post-operative infarctions with permanent deficits (5%). Angiographic follow-up was available in 54 aneurysms (90%), mean time to last follow-up 12.2 months (median 6.5 months, 3.3-33.4 months). At last follow-up, 25 aneurysms were completely occluded (46%, Raymond 1), 20 showed residual neck (37%, Raymond 2), and 9 demonstrated residual aneurysm (17%, Raymond 3). Nine aneurysms were retreated (17%), 6 with flow-diversion and 3 with stent assisted-coiling. Compared to a prior study examining 84 large aneurysms treated with conventional coils, treatment with PC400 coils resulted in higher packing densities, faster procedure times, lower procedural complications and lower retreatment rates (Tables 1 and 2). Conclusion The PC400 system is safe and effective for the treatment of large wide-neck intracranial aneurysms, achieving high packing densities, fast procedural times, favorable safety profile and low re-treatment rates compared to conventional coiling. Disclosures: J. Delgado Almandoz: 2; C; Penumbra, Inc. Y. Kayan: 2; C; Penumbra, Inc. J. Fease: None. J. Scholz: None. A. Milner: None. A. Wallace: None. M. Mulder: None.

Purpose To examine clinical and angiographic outcomes in a cohort of consecutive patients with recurrent intracranial aneurysms treated with the Pipeline Embolization Device (PED) at a referral center. Methods We conducted a retrospective review of all patients with recurrent intracranial aneurysms treated with the PED in our center center between December 13 th , 2011 and March 29 th , 2017. Baseline patient and aneurysm characteristics, intra-­operative, peri-­operative and delayed complications were recorded. Aneurysm volumes in initial and follow-­up angiographic studies were calculated using AngioCalc. Clinical outcomes were categorized using the modified Rankin Scale (mRS). Results 50 patients underwent 53 PED procedures to treat 56 recurrent intracranial aneurysms during the study period. 36 patients were women (72%) and 14 men (28%). Mean age was 58 years (range 29–­77 years). 23 patients were active smokers (46%) and 26 had a prior history of subarachnoid hemorrhage (52%). 46 patients were premedicated with aspirin/clopidogrel (92%), 3 with aspirin/prasugrel (6%) and 1 with warfarin/clopidogrel (2%). All patients underwent pre-procedure VerifyNow testing. 46 aneurysms were recurrent after simple coiling (82%), 5 after PED embolization (9%, 1 after PED/coiling), 3 after stent-assisted coiling (5%), 1 after Onyx HD500 embolization (2%) and 1 after surgical clipping (2%). 4 aneurysms were symptomatic from mass effect (7%) and 1 was acutely ruptured (2%). 3 aneurysms were fusiform (5%) and 1 blister (2%). 39 aneurysms were located in the internal carotid artery (70%), 8 in the middle cerebral artery (14%), 5 in the anterior cerebral artery (9%), 3 in the posterior inferior cerebellar artery (5%) and 1 in the basilar tip (2%). 30 aneurysms had a vessel arising from the aneurysm dome/neck (54%), 14 of which were the posterior communicating artery (47%). Mean aneurysm size was 6.2 mm (1.5–26.2 mm), mean neck was 3.9 mm (0.5–9.3 mm), mean dome-­to-­neck ratio was 1.6 (0.6–11.5). 24 aneurysms were wide-neck (≥4 mm, 43%). Mean number of PEDs deployed per aneurysm was 0.9. Adjunctive coiling was performed in 7 aneurysms (12.5%, mean 4.7 coils deployed). 28 aneurysms were treated with PED Flex (50%). There were 4 intra-operative (7.5%), 15 peri-operative (28%) and 3 delayed (5.7%) complications. 1 peri-operative complication, an ipsilateral intracerebral hemorrhage on post-operative day 4 in a patient with P2Y12 reception over-inhibition at the time of the hemorrhage, resulted in the patient’s death (1.9%). No other treatment-related complication led to a disabling neurological deficit or death (mRS ≥3). Treatment-related mortality was 2%. There were no post-­operative aneurysm ruptures. Angiographic follow-­up was available in 47 aneurysms (86%, 8 follow-ups currently pending), with a mean time to last angiographic follow-­up of 20 months. At last follow­-up, 36 aneurysms were completely occluded (77%), 2 aneurysms had near-completed occlusion (4%, mean 97.3% vol reduction), and 9 aneurysms had incomplete occlusion (19%, mean 68.7% vol reduction). No aneurysms required retreatment. Conclusion The PED is a safe and effective treatment for recurrent intracranial aneurysms, with high long-term complete aneurysm occlusion rates, low re-­treatment rates, and a low rate of major treatment-related complications. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Accriva Diagnostics. Y. Kayan: 2; C; Medtronic Neurovascular. J. Fease: None. K. Uittenbogaard: None. J. Scholz: None. A. Milner: None. K. Nelson: None. A. Wallace: None. M. Mulder: None.

Flow diversion constitutes a pivotal advancement in endovascular intracranial aneurysm treatment, but requires development of a new skill set. The aim of this study is to determine whether outcomes after treatment with the Pipeline Embolization Device improve with experience. We retrospectively reviewed all patients with intracranial aneurysms treated with Pipeline at two centers over a 4.5-year period. Baseline patient and aneurysm characteristics, complications, and angiographic outcomes were analyzed. One hundred forty patients underwent 150 Pipeline procedures to treat 167 intracranial aneurysms during the study period, 109 women, mean age 55.4 years. One hundred twenty-six aneurysms were ICA, mean size 10.2 mm and mean neck 6.4 mm. Intra-procedural technical difficulties were higher during the first 75 procedures compared with the subsequent 75 (13.3 vs 2.7%; p = 0.03), as combined major morbidity and neurological mortality (14.7 vs 4%; p = 0.046). In multivariate regression analysis, increased operator experience with Pipeline remained an independent predictor of intra-procedural technical difficulties (p = 0.02, odds ratio (OR) 0.015, 95% CI 0.0004–0.55) and combined major morbidity and neurological mortality (p = 0.03, OR 0.16, 95% CI 0.03–0.84). At last follow-up, 123 aneurysms were completely occluded (81.5%, mean 24 months). In our cohort, age ≤ 53 years was an independent predictor of complete aneurysm occlusion at last follow-up (p = 0.001, OR 0.92, 95% CI 0.88–0.97). Five aneurysms were retreated (3.3%). The Pipeline embolization device is an effective treatment for intracranial aneurysms. The risk of intra-procedural technical difficulties and combined major morbidity and neurological mortality decreases significantly with increased operator experience in Pipeline deployment and patient management.

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

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: 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 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.

PurposeTo compare rates of symptomatic intracranial hemorrhage (SICH) and good clinical outcome at 90 days in patients with ischemic strokes from anterior circulation emergent large vessel occlusions (ELVO) treated with mechanical thrombectomy using either Solumbra or A Direct Aspiration first-Pass Thrombectomy (ADAPT) techniques.MethodsWe compared clinical characteristics, procedural variables, and clinical outcomes in patients with anterior circulation ELVOs treated with mechanical thrombectomy using either a Solumbra or ADAPT technique at our institution over a 38-month period. SICH was defined using the SITS-MOST criteria. A good clinical outcome was defined as a modified Rankin Scale score of 0–2 at 90 days.ResultsOne hundred patients were included, 55 in the Solumbra group and 45 in the ADAPT group. Patients in the ADAPT group had higher National Institutes of Health Stroke Scale (NIHSS) (19.2 vs 16.8, p=0.02) and a higher proportion of internal carotid artery terminus thrombi (42.2% vs 20%, p=0.03) than patients in the Solumbra group. Patients in the ADAPT group had a trend toward a lower rate of SICH than patients in the Solumbra group (2.2% vs 12.7%, p=0.07). Patients in the ADAPT group had a significantly higher rate of good clinical outcome at 90 days than patients in the Solumbra group (55.6% vs 30.9%, p=0.015). Use of the ADAPT technique (OR 6 (95% CI 1.0 to 31.2), p=0.049) was an independent predictor of a good clinical outcome at 90 days in our cohort.ConclusionsIn our cohort, the ADAPT technique was associated with significantly higher good clinical outcomes at 90 days in patients with acute ischemic stroke due to anterior circulation ELVOs treated with mechanical thrombectomy.

Purpose To compare procedural and clinical outcomes in patients with anterior circulation acute ischemic strokes treated with mechanical thrombectomy using ADAPT technique only or ADAPT with Solumbra salvage. Materials and methods We restrospectively reviewed a consecutive cohort of patients with anterior circulation acute ischemic strokes treated with mechanical thrombectomy using ADAPT technique only or ADAPT with Solumbra salvage at our institution between March 11th, 2013 and December 31st, 2015. Baseline clinical and radiological characteristics and procedural variables were recorded. Clinical outcomes at 90 days were recorded using the modified Rankin Scale (mRS). Results Fifty-nine patients were included, 33 male (56%). Mean age 67.1 years, mean admission NIHSS 19.1. Forty-six patients were treated with ADAPT only (78%) and 13 with ADAPT with Solumbra salvage (22%). Table 1 summarizes baseline clinical and radiological characteristics. There was a trend towards a higher proportion of patients with ICA terminus thrombi in the ADAPT with Solumbra salvage group (69.2%, p-value 0.054). Table 2 summarizes the procedural variables. There was a significantly-lower mean time from puncture to reperfusion in the ADAPT only group (29.5 minutes) compared to the ADAPT with Solumbra salvage group (85.1 minutes, p-value Conclusion Among patients treated with mechanical thrombectomy using an ADAPT-first approach, those requiring Solumbra salvage had significantly-higher rates of unfavorable clinical outcome and death at 90 days. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Penumbra, Inc. Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra, Inc. M. Young: None. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. T. Hehr: None. M. Mulder: None. R. Tarrel: None.

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

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.

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: 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.

Purpose To examine long-term clinical and angiographic outcomes in a consecutive cohort of patients with cerebral aneurysms treated with the Pipeline Embolization Device (PED) in 2 referral centers. Materials and methods We conducted a retrospective review of all patients with cerebral aneurysms treated with the PED at 2 referral medical centers between March 10th, 2011 and November 5th, 2015. Baseline patient and aneurysm characteristics, intra-operative, peri-operative and delayed complications were recorded. Aneurysm volumes in initial and follow-up angiographic studies were calculated using AngioCalc. Clinical outcomes were categorized using the modified Rankin Scale (mRS). Results 140 patients underwent 150 PED procedures to treat 166 cerebral aneurysms during the study period. 109 patients were women (78%) and 31 men (22%). Mean age was 55 years (range 15–81 years). 87 aneurysms were incidental (52%), 39 recurrent (24%), 23 symptomatic (14%) and 17 ruptured (10%, 11 treated sub-acutely and 6 treated acutely). 22 aneurysms were fusiform (13%), 7 dissecting (4%) and 6 blister (4%). 125 aneurysms were located in the internal carotid (75%), 15 in the middle cerebral (9%), 10 in the anterior cerebral (6%), 10 in the vertebral (6%), 4 in the basilar (2%) and 2 in the posterior cerebral arteries (1%). Mean aneurysm size was 10.2 mm, mean neck was 6.4 mm, mean dome-to-neck ratio was 1.6. Mean number of PEDs deployed per aneurysm was 1.1. Adjunctive coiling was performed in 15 aneurysms (9%). The table summarizes the intra-operative, peri-operative and delayed complications, categorized by the first 75 and subsequent 75 PED procedures. There was a statistically-significant decrease in the rate of any intra-operative as well as disabling treatment-related complications between the first 75 and next 75 PED procedures. Similarly, there was a trend toward a decrease in treatment-related mortality between the first 75 and the next 75 PED procedures. Angiographic follow-up was obtained in 139 aneurysms (84%), with a mean time to last angiographic follow-up of 18.1 months. At last follow-up, 109 aneurysms were completely occluded (78.4%), 10 had near-complete occlusion (≥90% volume reduction, 7.2%), and 20 aneurysms had Conclusions The PED is an effective treatment for wide-neck cerebral aneurysms, with high long-term complete/near-complete aneurysm occlusion rates and low retreatment rates. The risk of intra-operative and disabling treatment-related complications decreases significantly with increased experience in PED use and patient management. Disclosures J. Delgado Almandoz: 2; C; MedTronic Neurovascular. O. Tenreiro-Picon: None. Y. Kayan: 2; C; MedTronic Neurovascular. J. Fease: None. J. Scholz: None. A. Milner: None. M. Mulder: None. A. Tenreiro: None.

Background and purpose Long-term clinical outcomes in patients with acute ischemic stroke (AIS) treated with mechanical thrombectomy (MT) are not well understood. This study aims to determine long-term clinical outcomes in a consecutive cohort of patients with AIS treated with MT who had moderate or moderate severe disability at 90 day follow-up. Methods Our prospectively-maintained institutional neurointerventional database was queried to identify all patients with AIS treated with MT at our institution from July 1st, 2011 until September 30th, 2015 who had moderate (modified Rankin Scale, mRS, 3) or moderate severe (mRS 4) disability at the time of the 90 day follow-up. At least 6 months after stroke onset, medical records were reviewed and/or phone interviews were conducted by a nurse certified in the mRS and independent of the MT procedure to determine the mRS at the time of last clinical contact. Baseline clinical and radiological characteristics were also obtained. Results Forty patients met the study9s inclusion criteria, comprising 29% of patients treated with MT at our institution during the study period. Twenty patients were male (50%) and 20 female (50%). At presentation, 14 patients had a history of atrial fibrillation (35%), 28 hypertension (70%) and 13 diabetes mellitus (33%). Mean age was 69.8 years. Mean admission NIHSS was 18.2. Twenty-five patients received intravenous tissue plasminogen activator (63%). Thrombus location was M1 segment in 18 patients (45%), internal carotid artery terminus in 14 patients (35%), basilar artery in 4 patients (10%) and M2/M3 segment in 4 patients (10%). Discharge disposition was acute inpatient rehabilitation in 26 patients (65%) and skilled nursing facility in 14 patients (35%). At the time of the 90 day follow-up visit, 18 patients had an mRS of 3 (45%) and 22 had an mRS of 4 (55%). All patients continued to undergo outpatient rehabilitation treatment after the 90 day follow-up visit. Mean time to long-term clinical follow-up was 21.5 months after stroke onset (median 18.8 months, range 6–49 months). The table illustrates the clinical outcomes at the time of long-term follow-up. Between the 90 day and long-term follow-ups, 12 patients (30%) had a reduction of at least 1 point in the mRS, whereas 10 patients (25%) had an increase of at least 1 point in the mRS. At the time of long-term follow-up, 23 patients lived at home (58%), 3 in an assisted living facility (8%), 6 in a skilled nursing facility (15%) and 8 were deceased (20%). Four patients had experienced a recurrent AIS (10%) by the time of long-term follow-up. Conclusion Among patients with AIS treated with MT who had moderate or moderate severe disability at 90 days, a considerable minority (30%) demonstrated a reduction in long-term disability with continued outpatient rehabilitation. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Penumbra, Inc. S. Hochsprung: None. Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra, Inc. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. M. Mulder: None. T. Hehr: None. R. Tarrel: None. D. Chappuis: None. M. Young: None.

Introduction Safe and effective endovascular treatment of acute ischemic stroke is dependent on prompt intervention. In light of the positive trials published last year, we intensified our efforts to improve the process of taking patients from the emergency department to the angiography suite for mechanical thrombectomy. Methods At the beginning of 2015, a process improvement project to improve door-to-groin puncture times for mechanical thrombectomy for emergent large vessel occlusions was undertaken at our institution. After a systematic analysis of the process, the following key changes were standardized: early consultation with the neurointerventionalist for patients presenting with a high National Institutes of Health Stroke Scale (NIHSS ≥6), the stroke neurologist and the neurointerventionalist meet the patient in the emergency department for transfers or meet in the CT department for non-transfers, elimination of emergency physician triage for medically stable patients, elimination of lab tests such as creatinine, establishment of a minimum level of clinical information required for the sedation nurse to care for stroke patients safely, institution of a “stroke bag” containing all necessary devices to perform efficient thrombectomy, standardized setup of the procedure table and devices for all operators, calling for patients when the sedation nurse is ready without waiting for the entire team, elimination of unnecessary preoperative steps (e.g. Foley catheter placement, groin shaving, checking of distal pulses), and institution of an abbreviated time-out procedure. All attempted thrombectomies performed in 2013 and 2014 were compared to those performed in 2015 visa-vis the following variables: door-to-groin puncture time, symptomatic intracranial hemorrhage (SICH) rate as defined by SITS-MOST criteria, 90 day mortality rate, and 90 day rate of good clinical outcome defined by a modified Rankin Scale (mRS) of 0–2. A one-tailed Student’s t-test and Fisher’s exact tests were performed. A p-value Results From January 2013 to December 2015, we attempted 108 mechanical thrombectomies. Of these, 43 were in 2015 (40%). Both the mean and median door-to-groin puncture times were significantly reduced from the previous two years (35 minutes versus 89 minutes and 22 minutes versus 73 minutes, respectively, p Conclusion Our systematic process improvement initiative significantly reduced door-to-groin puncture times and showed a trend towards reduced mortality at 90 days. A multidisciplinary approach and ensuring hospital system investment are key to an effective process. Disclosures Y. Kayan: 2; C; Medtronic, Penumbra. J. Delgado Almandoz: 2; C; Medtronic, Penumbra. M. Young: None. J. Fease: None. J. Scholz: None. A. Milner: None. T. Hehr: None. M. Mulder: None. P. Roohani: None. R. Tarrel: None.

Purpose: To determine the yield of catheter angiography for the detection of causative vascular lesions in patients with subarachnoid hemorrhage (SAH) who have a negative initial non-invasive neurovascular examination. Methods: Between January 1st, 2006 and August 1st, 2011, we instituted a prospective protocol by which patients who presented to our institution with SAH and had a negative initial non-invasive neurovascular examination (CT or MR angiogram [CTA, MRA]) were examined with catheter angiography to detect causative vascular lesions. Two experienced neuroradiologists evaluated the NCCTs to determine the pattern of SAH (diffuse, perimesencephalic or peripheral) and the catheter angiograms to assess for the presence of a causative vascular lesion. All differences in reader interpretation were resolved by consensus. Results: Forty-eight patients were included in our study, with a mean age of 58 years (median 59 years, range 25-84 years). Twenty-six patients were male (54.2%) and 22 female (45.8%). Twenty-eight patients had diffuse SAH (58.3%), 11 peripheral SAH (22.9%) and 9 perimesencephalic SAH (18.8%). The initial non-invasive neurovascular examination was a CTA in 41 patients (85.4%) and an MRA in 7 patients (14.6%). A second catheter angiogram was performed in 30 patients (62.5%). Mean time interval between the initial non-invasive neurovascular examination and the first catheter angiogram was 0.9 days (median 1 day, range 0-7 days) and the second catheter angiogram was 12.2 days (median 8.5 days, range 4-69 days). Catheter angiography demonstrated a causative vascular lesion in 4 patients (8.3%), 3 of which had diffuse SAH (yield of 10.7%) and 1 had peripheral SAH (yield of 9.1%). Of note, 1 of the causative vascular lesions was identified in a second catheter angiogram performed 8 days after the CTA in a patient with diffuse SAH. The vascular lesions identified were 2 dural arteriovenous fistulas, 1 pial cerebellopontine angle arteriovenous malformation with a 2-mm feeding artery aneurysm located in the internal auditory canal ( Figure ), and a 3-mm anterior communicating artery aneurysm. Two of the vascular lesions underwent endovascular embolization, 1 radiosurgery and 1 endovascular embolization followed by radiosurgery. In retrospect, the vascular lesion could be seen in the initial examination in 2 patients. Conclusion: Catheter angiography is a valuable tool in the evaluation of patients with diffuse and peripheral SAH who have a negative initial non-invasive neurovascular examination, demonstrating a causative vascular lesion in 10.7% and 9.1% of patients, respectively.

Purpose: To determine the yield of repeat CT angiography for the detection of causative vascular lesions in patients with subarachnoid hemorrhage (SAH) who have negative initial CT and catheter angiograms. Methods: We conducted a retrospective review of patients who presented to our institution between January 1st, 2008 and August 1st, 2011 with SAH and negative initial CT and catheter angiograms who were examined with repeat CT angiography in order to determine the yield of this imaging modality for the detection of causative vascular lesions. Two experienced neuroradiologists evaluated the NCCTs to determine the pattern of SAH (diffuse, perimesencephalic or peripheral) and the CT angiograms (CTA) to assess for the presence of a causative vascular lesion. All differences in reader interpretation were resolved by consensus. Results: Twenty-two patients were included in our study, with a mean age of 78 years (median 59 years, range 28-78 years). Sixteen patients were male (72.7%) and 6 female (27.3%). Seventeen patients had diffuse SAH (77.3%), 4 perimesencephalic SAH (18.2%) and 1 peripheral SAH (4.5%). Mean time interval between the initial neurovascular examination and the repeat CTA was 26.5 days (median 20.5 days, range 2-150 days). The repeat CTA demonstrated a causative vascular lesion in 2 patients (9.1%), all of which had diffuse SAH (yield of 11.8%). The vascular lesions identified were 1 small pontine arteriovenous malformation and a 2-mm supraclinoid internal carotid artery aneurysm ( Figure ). The pontine arteriovenous malformation underwent radiosurgery and the internal carotid artery aneurysm underwent surgical clipping. In retrospect, none of these vascular lesions were evident in the initial CT or catheter angiograms. Conclusion: Repeat CT angiography is valuable in the evaluation of patients with diffuse SAH who have negative initial CT and catheter angiograms, demonstrating a causative vascular lesion in 11.8% of patients.

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.

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 …

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.

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.