R Anderson

Pre-procedure P2Y12 reaction units value predicts perioperative thromboembolic and hemorrhagic complications in patients with cerebral aneurysms treated with the Pipeline Embolization Device

Background There is wide variability in the reported incidence of perioperative thromboembolic (0–14%) and hemorrhagic (0–11%) complications after Pipeline Embolization Device (PED) procedures for cerebral aneurysm treatment, which could be partly due to differences in patient response to the P2Y12 receptor antagonist administered while the PED endothelializes. This study aims to identify an optimal pre-procedure P2Y12 reaction units (PRU) value range and determine the independent predictors of perioperative thromboembolic and hemorrhagic complications after PED procedures. Methods We recorded patient and aneurysm characteristics, P2Y12 receptor antagonist administered, pre-procedure PRU value with VerifyNow, procedural variables and perioperative thromboembolic and hemorrhagic complications up to postoperative day 30 after PED procedures at our institution during an 8-month period. Perioperative complications were considered major if they caused a permanent disabling neurological deficit or death. Multivariate regression analysis was performed to identify independent predictors of perioperative complications in our cohort. Results Forty-four patients underwent 48 PED procedures at our institution during the study period. There were eight thromboembolic and hemorrhagic perioperative complications in our cohort (16.7%), four of which were major (8.3%). A pre-procedure PRU value of <60 or >240 (p=0.02) and a technically difficult procedure (p=0.04) were independent predictors of all perioperative complications. A pre-procedure PRU value of <60 or >240 (p=0.004) and a history of hypertension (p=0.03) were independent predictors of major perioperative complications. Conclusions In our cohort, a pre-procedure PRU value of <60 or >240 was the strongest independent predictor of all and major perioperative thromboembolic and hemorrhagic complications after PED procedures.

Last-Recorded P2Y12 Reaction Units Value Is Strongly Associated with Thromboembolic and Hemorrhagic Complications Occurring Up to 6 Months after Treatment in Patients with Cerebral Aneurysms Treated with the Pipeline Embolization Device

BACKGROUND AND PURPOSE: A recent study identified a preprocedural P2Y12 reaction units value of <60 or >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 <60 or >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 <60 or >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 <60 or >240 was the only independent predictor of all and major thromboembolic and hemorrhagic complications up to 6 months after Pipeline Embolization Device procedures.

Diagnostic Yield of Catheter Angiography in Patients with Subarachnoid Hemorrhage and Negative Initial Noninvasive Neurovascular Examinations

These authors explored the diagnostic yield of DSA in patients with SAH and previously negative CTA or MRA. A total of 55 patients who presented with diffuse SAH, perimesencephalic SAH, or sulcal SAH received CTA (n= 47) or MRA (n= 8). Despite normal findings on CTA or MRA, DSA showed vascular lesions in 11% of patients with diffuse SAH and in 1 patient with sulcal SAH. The investigators concluded that DSA is a valuable tool in patients with diffuse or sulcal SAH in whom previous noninvasive examinations are negative. 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.

Diagnostic yield of delayed neurovascular imaging in patients with subarachnoid hemorrhage, negative initial CT and catheter angiograms, and a negative 7 day repeat catheter angiogram

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.

E-065 Medium-Term Clinical Outcome of Patients with Aneurysmal Subarachnoid Haemorrhage Treated Endovascularly within the Framework of a Multi-Disciplinary Neurovascular Team at a Tertiary Referral Medical Centre over a 45-Month Period

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 Abstract E-065 Table 1 All patients: Admission Hunt-Hess 1-2: Admission Hunt-Hess 3: Admission Hunt-Hess 4-5: p-value: All patients: 116 (100%) 50 (43.1%) 32 (27.6%) 34 (29.3%) mRS 0-2: 83 (71.6%) 47 (94%) 22 (68.8%) 14 (41.2%) mRS 3: 13 (11.2%) 1 (2%) 4 (12.5%) 8 (23.5%) mRS 4-5: 7 (6%) 0 2 (6.3%) 5 (14.7%) mRS 6: 13 (11.2%) 2 (4%) 4 (12.5%) 7 (20.6%) <0.0001 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.

E-064 ASPECTS ≥5 on Non-Contrast CT and CT Angiography Source Images Predicts Clinical Outcome in a Cohort of 30 Patients Undergoing Mechanical Thrombectomy with Stent-Retrievers

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. Abstract E-064 Table 1 All patients: ≤65 years: >65 years: p-value: CTA-SI ASPECTS: 0-4 5-10 0-4 5-10 0-4 5-10 N: 9 11 5 4 4 7 mRS 0–2: 1 7 1 4 0 3 mRS 3–6: 8 4 4 0 4 4 % mRS 0–2: 11.1 63.6 20 100 0 42.9 0.023 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.

O-018 Variability in Response to a 75mg Daily Clopidogrel Dose in a Cohort of 90 Patients Undergoing Endovascular Treatment of Unruptured Cerebral Aneurysms

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<60 considered a hyper-response to clopidogrel therapy (P2Y12 receptor over-inhibition. 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<60) and 14 patients exhibited a hypo-response to clopidogrel therapy (15.6%, 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). Abstract O-018 Figure 1 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.

P-005 Last-Recorded P2Y12 Reaction Units Value Predicts Thromboembolic and Haemorrhagic Complications Occurring up to 6 Months after Treatment in Patients with Cerebral Aneurysms Treated with the Pipeline Embolisation Device

Background and Purpose A recent study identified a pre-procedure P2Y12 reaction units (PRU) value <60 or >240 as a strong independent predictor of perioperative thromboembolic and haemorrhagic complications occurring up to 30 days after treatment of cerebral aneurysms with the Pipeline Embolisation Device (PED). This study aims to determine if a last-recorded PRU value <60 or >240 predicts thromboembolic and haemorrhagic complications occurring up to 6 months after treatment of cerebral aneurysms with the PED in the same patient cohort. Methods We recorded patient and aneurysm characteristics, P2Y12 receptor antagonist administered, PRU value with VerifyNow, procedural variables, number of P2Y12 receptor antagonist dose adjustments, and thromboembolic and haemorrhagic complications occurring up to 6 months after PED procedures at our institution during an 8-month period. Complications causing a permanent disabling neurological deficit or death were considered major. Multivariate regression analysis was performed to identify independent predictors of thromboembolic and haemorrhagic complications. Target P2Y12 receptor inhibition range was initially 80–200 PRU and was subsequently expanded to 60–240 PRU. Results Forty-four patients underwent 48 PED procedures at our institution during the study period. There were 11 thromboembolic and haemorrhagic complications occurring up to 6 months after treatment in our cohort (22.9%), 5 of which were major (10.4%). Among the 5 major complications, 4 occurred in the perioperative period and 1 occurred on post-operative day 50 (ICH with subdural extension contralateral to the PED in a patient with autopsy-proven amyloid angiopathy). Four of the 5 major complications occurred in patients who exhibited markedly elevated (292) or decreased (0, 10, 58) PRU values shortly before or at the time of the complication. A last-recorded PRU value <60 or >240 was the only independent predictor of all (p-value 0.002) and major (p-value 0.03) thromboembolic and haemorrhagic complications in our cohort (Table). Most patients (71%) required, on average, 2 adjustments to the dose or type of P2Y12 receptor antagonist administered to remain within the 60–240 target PRU range. Conclusion In our cohort, a last-recorded PRU value <60 or 240> was the only independent predictor of all and major thromboembolic and haemorrhagic complications up to 6 months after PED procedures. Abstract P-005 Table 1 Complications Occurring up to 6 Months after PED Procedures According to Last-Recorded PRU Value All Complications Thromboembolic Complications Haemorrhagic Complications All Major p-value* All Major p-value* All Major p-value* All Procedures, n=48 11 (22.9%) 5 (10.4) 6 (12.5%) 1 (2.1%) 5 (10.4%) 4 (8.3%) PRU >60, n=9 5 (55.6%) 3 (33.3%) 1 (11.1%) 0 4 (44.4%) 3 (33.3%) PRU 60-240, n=37 4 (10.8%) 1 (2.7%) 3 (8.1%) 0 1 (2.7%) 1 (2.7%) PRU <240, n=2 2 (100%) 1 (50%) <0.001/0.011 2 (100%) 1 (50%) 0.014 / 0.042 0 0.004 / 0.036 * p-value for the difference between all / major complications Disclosures J. Delgado Almandoz: 2; C; Covidien/ev3. B. Crandall: 2; C; Covidien/ev3. J. Fease: None. J. Scholz: None. R. Anderson: None. Y. Kadkhodayan: None. D. Tubman: 2; C; Covidien/ev3, MicroVention.

O-035 Variability in clopidogrel response and associated perioperative thromboembolic and hemorrhagic complications in the initial cohort of patients treated with the pipeline device at a tertiary referral medical center

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 <20% inhibition, (2) poor responder if PRUs 200–240 or 20%–39% inhibition, (3) hyper-responder if PRUs <40 or ≥90% inhibition. Perioperative thromboembolic and hemorrhagic complications were recorded.Abstract O-035 Table 1 Dual Anti-Platelet Therapy Regimens and Associated Perioperative Complications First Group (n=6): Second Group (n=15): Initiation of dual anti-platelet therapy regimen 7 days pre-procedure 10 days pre-procedure Aspirin/Clopidogrel dosing 325 mg PO QD/300 mg PO ×1, then 75 mg PO QD 325 mg PO QD/75 mg PO QD Pre-procedure P2Y12 inhibition testing Day of procedure 1 day before procedure Regimen for non-responders (PRUs >240 or <20% inhibition) Prasugrel 60 mg PO × 1, then 10 mg PO QD Prasugrel 60 mg PO × 1, then 10 mg PO QD Regimen for poor responders (PRUs 200–240 or 20%–39% inhibition) Clopidogrel 150 mg PO QD Prasugrel 30 mg PO × 1, then 10 mg PO QD Regimen for hyper-responders (PRUs <40 or ≥90% inhibition) Clopidogrel, 75 mg PO QOD Clopidogrel, 75 mg PO QOD Post-procedure P2Y12 inhibition testing None, unless symptomatic with abnormal bruising or bleeding 30–45 days after first clopidogrel dose, earlier if symptomatic with abnormal bruising or bleeding Thromboembolic / Hemorrhagic complications 2 (33.3%, 1 TIA, 1 infarction leading to a new permanent neurological deficit)/1 ICH not leading to a new permanent neurological deficit (16.7%) 1 infarction not leading to a new permanent neurological deficit (6.7%)/None Overall perioperative complications 3 (50%) 1 (6.7%), p value: 0.053 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.

O-027 In-hospital mortality and short-term clinical outcome in octo- and non-agenarian patients with aneurysmal subarachnoid hemorrhage treated endovascularly at a tertiary referral medical center

Purpose To determine the in-hospital mortality and short-term clinical outcome in a cohort of octo- and non-agenarian patients with aneurysmal subarachnoid hemorrhage (SAH) treated endovascularly at a tertiary referral medical center. Methods We retrospectively identified all octo- and non-agenarian patients with aneurysmal SAH who were treated endovascularly at our institution from January 1, 1997 until December 31, 2011. We reviewed the (1) medical records to determine patient age, gender, admission Hunt-Hess scale (HHS), periprocedural complications, length of hospital stay, in-hospital mortality and modified Rankin Scale (mRS) at hospital discharge among survivors, and (2) treatment catheter angiograms to determine aneurysm location, maximum dimension and immediate post-treatment Raymond scale. Good clinical outcome was defined as an mRS 0–3 at hospital discharge. Results A total of 23 octo- and non-agenarian patients had aneurysmal SAH and were treated endovascularly at our institution during our studys 15-year time period. Twenty patients were female (87%) and 3 male (13%), with a mean age of 84.2 years (median 83 years, range 80–97 years). Admission HHS was 1–2 in 5 patients (21.7%), three in eight patients (34.8%) and 4–5 in 10 patients (43.5%). Aneurysm locations were: six in the posterior communicating artery (26.1%), five in the middle cerebral artery (21.7%), four in the anterior communicating artery (17.4%), two in the basilar artery (8.7%), two in the internal carotid artery (8.7%), two in the posterior inferior cerebellar artery (8.7%), one in the superior cerebellar artery (4.3%) and one in the vertebral artery (4.3%). Mean maximum aneurysm sac dimension was 6.5 mm (median 5 mm, range 3–14 mm). Immediately post-treatment, 16 patients had complete aneurysm occlusion (69.6%), six had a neck remnant (26.1%) and one had residual aneurysm sac filling (4.3%). Thromboembolic complications occurred in four patients (17.4%), leading to a cerebral infarction in 1 patient (4.3%). Mean length of hospital stay was 14.6 days (median 12 days, range 3–30 days). In-hospital mortality was 30.4%. Among the 16 survivors, there was a 50% chance of a good clinical outcome at hospital discharge (mRS 0–3). There was a statistically-significant difference in the likelihood of a good clinical outcome at hospital discharge (mRS 0–3) between the five patients with admission HHS of 1–2 (80%) and the 18 patients with admission HHS of 3–5 (22.2%, p value 0.033, Abstract O-027 table 1).Abstract O-027 Table 1 Short term clinical outcome in octo and non-agenarians with SAH treated endovascularly All patients (n=23) HHS 1-2 (n=5) HHS 3 (n=8) HHS 4–5 (n=10) In-Hospital Mortality 30.4 0 37.5 40 Good Outcome Among Survivors (mRS 0–3) 50 80 40 33.3 Poor Outcome Among Survivors (mRS 4–5) 50 20 60 66.7 Overall Good Outcome (mRS 0–3) 34.8 80 22.2, p value: 0.033 Overall poor outcome (mRS 4–6) 65.2 20 77.8 Conclusion In-hospital mortality was relatively low (30.4%) and there was a fair chance of a good clinical outcome at hospital discharge among survivors (50%) in our cohort of octo- and non-agenarian patients with aneurysmal SAH treated endovascularly. Furthermore, patients with admission HHS 1–2 had no in-hospital deaths and demonstrated a significantly higher likelihood of an overall good clinical outcome at hospital discharge (80%) compared to patients with admission HHS 3–5 (22%). Competing interests None.