Machine learning predicts cerebral vasospasm in patients with subarachnoid haemorrhage.

BACKGROUND: Cerebral vasospasm (CV) is a feared complication which occurs after 20-40% of subarachnoid haemorrhage (SAH). It is standard practice to admit patients with SAH to intensive care for an extended period of resource-intensive monitoring. We used machine learning to predict CV requiring verapamil (CVRV) in the largest and only multi-center study to date. METHODS: Patients with SAH admitted to UCLA from 2013 to 2022 and a validation cohort from VUMC from 2018 to 2023 were included. For each patient, 172 unique intensive care unit (ICU) variables were extracted through the primary endpoint, namely first verapamil administration or no verapamil. At each institution, a light gradient boosting machine (LightGBM) was trained using five-fold cross validation to predict the primary endpoint at various hospitalization timepoints. FINDINGS: A total of 1750 patients were included from UCLA, 125 receiving verapamil. LightGBM achieved an area under the ROC (AUC) of 0.88 > 1 week in advance and ruled out 8% of non-verapamil patients with zero false negatives. Our models predicted "no CVRV" vs "CVRV within three days" vs "CVRV after three days" with AUCs = 0.88, 0.83, and 0.88, respectively. From VUMC, 1654 patients were included, 75 receiving verapamil. VUMC predictions averaged within 0.01 AUC points of UCLA predictions. INTERPRETATION: We present an accurate and early predictor of CVRV using machine learning with multi-center validation. This represents a significant step towards optimized clinical management and resource allocation in patients with SAH. FUNDING: Robert E. Freundlich is supported by National Center for Advancing Translational Sciences federal grant UL1TR002243 and National Heart, Lung, and Blood Institute federal grant K23HL148640; these funders did not play any role in this study. The National Institutes of Health supports Vanderbilt University Medical Center which indirectly supported these research efforts. Neither this study nor any other authors personally received financial support for the research presented in this manuscript. No support from pharmaceutical companies was received.

Use of a large-bore 088 intracranial access support catheter for delivery of large intracranial devices: case series with the TracStar LDP in 125 cases.

BACKGROUND: The delivery of neuroendovascular devices requires a robust proximal access platform. This demand has previously been met with a 6Fr long sheath (8Fr guide) that is placed in the proximal internal carotid artery (ICA) or vertebral artery segments. We share our experience with the first 0.088 inch 8Fr guide catheter designed for direct intracranial access. METHODS: We retrospectively reviewed a prospectively maintained IRB-approved institutional database of the senior authors to identify all cases where the TracStar Large Distal Platform (LDP) was positioned within the intracranial vasculature, defined as within or distal to the petrous ICA, vertebral artery (V3) segments, or transverse sinus. Technical success was defined as safe placement of the TracStar LDP within or distal to the described distal vessel segments with subsequent complication-free device implantation. RESULTS: Over the 41-month study period from January 2020 to June 2023, 125 consecutive cases were identified in whom the TracStar LDP was navigated into the intracranial vasculature for triaxial delivery of large devices, 0.027 inch microcatheter and greater, for aneurysm treatment (n=108, 86%), intracranial angioplasty/stenting (n=15, 12%), and venous sinus stenting (n=2, 1.6%). All cases used a direct select catheter technique for initial guide placement (no exchange). Posterior circulation treatments occurred in 14.4% (n=18) of cases. Technical success was achieved in 100% of cases. No vessel dissections occurred in any cases. CONCLUSION: The TracStar LDP is an 0.088 inch 8Fr guide catheter that can establish direct intracranial access with an acceptable safety profile. This can be achieved in a wide range of neurointerventional cases with a high rate of technical success.

Feasibility of super-bore 0.088″ mechanical thrombectomy in M1 vessels smaller than 8 French: Experience in 20 consecutive cases.

INTRODUCTION: Superbore 0.088″ catheters provide a platform for optimizing aspiration efficiency and flow control during stroke mechanical thrombectomy procedures. New superbore catheters have the distal flexibility necessary to navigate complex neurovascular anatomy while providing the proximal support of traditional 8F catheters. The safety and feasibility of Zoom 88™ superbore angled-tip catheters in the middle cerebral artery (MCA) segments smaller than the catheter diameter have not been previously described. METHODS: Twenty consecutive cases of acute MCA mechanical thrombectomy were retrospectively identified from the senior authors' prospectively maintained Institutional Review Board-approved database, in which the Zoom 88 (Imperative Care, Campbell, CA) catheter was successfully navigated to at least the M1 segment. Patient demographics, procedural details, and periprocedural information were analyzed. Rates and averages (standard errors) are generally reported. RESULTS: The average National Institutes of Health Stroke Scale at presentation and age were 15 ± 2 and 73 ± 3 years, respectively. The M1 and M2 occlusions were evenly distributed. The average M1 measurements before thrombectomy ranged from 2.36 ± 0.07 mm proximally to 2.00 ± 0.11 mm distally, and after thrombectomy, they ranged from 2.34 ± 0.07 mm proximally to 1.97 ± 0.10 mm distally. First-pass modified thrombolysis in cerebral infarction (mTICI) 2C/3 recanalization was achieved in 40% of cases, and final mTICI 2C/3 recanalization was achieved in 90% of cases. A single case of mild vasospasm was managed with verapamil. No hemorrhagic or periprocedural complications were noted. CONCLUSION: Superbore 0.088″ catheters with flexible distal segments can be safely navigated to the MCA to augment mechanical thrombectomy even when the MCA segment is smaller than the catheter.

Triple Stentriever "Bouquet" Deployment with Zoom 88 Large-Bore Aspiration and Walrus Balloon-Guide Catheter for the Definitive Thrombectomy of a Carotid Free-Floating Thrombus.

Formation of a carotid free-floating thrombus (CFFT) is a rare and life-threatening condition without an optimal management plan. A 78-year-old woman with a history of prior right internal carotid artery (ICA) mechanical thrombectomy and antiplatelet noncompliance presented with transient ischemic attacks secondary to a recurrent CFFT in the right ICA. Given her symptoms and recurrent CFFT, endovascular mechanical thrombectomy was performed. A balloon guide-catheter (BGC) and a Zoom 88 distal access catheter were brought into the right distal common carotid artery and proximal ICA bulb, respectively. Three 0.021-inch microcatheters, each loaded with a unique stentriever, were navigated beyond the thrombus into the upper cervical ICA and deployed in a bouquet fashion. The BGC was inflated to achieve flow arrest, and the Zoom 88 aspiration catheter was tracked over the three bouquet stentrievers to ingest the thrombus. Follow-up angiography demonstrated recanalization of the proximal cervical ICA without evidence of residual thrombus. Twenty-four-hour postoperative computed tomography imaging did not reveal any evidence of new infarction. The patient was discharged home with an intact neurological examination, compliant on aspirin and apixaban. We demonstrate a novel technique utilizing a large-bore catheter with a triple stentriever "bouquet" to thrombectomize a CFFT.

Immediate procedural safety of adjunctive proximal coil occlusion in middle meningeal artery embolization for chronic subdural hematomas: Experience in 137 cases.

BACKGROUND: Endovascular embolization of the middle meningeal artery (MMA) has emerged as an adjunctive and stand-alone modality for the management of chronic subdural hematomas (cSDH). We report our experience utilizing proximal MMA coil embolization to augment cSDH devascularization in MMA embolization. METHODS: MMA embolization cases with adjunctive proximal MMA coiling were retrospectively identified from a prospectively maintained IRB-approved database of the senior authors. RESULTS: Of the 137 cases, all patients (n = 89, 100%) were symptomatic and underwent an MMA embolization procedure for cSDH. 50 of the patients underwent bilateral embolizations, with 53% (n = 72) for left-sided and 47% (n = 65) for right-sided cSDH. The anterior MMA branch was embolized in 19 (14%), posterior in 16 (12%), and both in 102 (74.5%) cases. Penetration of the liquid embolic to the contralateral MMA or into the falx was present in 38 (28%) and 31 (23%) cases, respectively, and 46 (34%) cases had ophthalmic or petrous collateral (n = 41, 30%) branches. MMA branches coiled include the primary trunk (25.5%, n = 35), primary and anterior or posterior MMA trunks (20%, n = 28), or primary with the anterior and posterior trunks (54%, n = 74). A mild ipsilateral facial nerve palsy was reported, which remained stable at discharge and follow-up. Absence of anterograde flow in the MMA occurred in 137 (100%) cases, and no cases required periprocedural rescue surgery for cSDH evacuation. The average follow-up length was 170 ± 17.9 days, cSDH was reduced by 4.24 ± 0.5(mm) and the midline shift by 1.46 ± 0.27(mm). Complete resolution was achieved in 63 (46.0%) cases. CONCLUSION: Proximal MMA coil embolization is a safe technique for providing additional embolization/occlusion of the MMA in cSDH embolization procedures. Further studies are needed to evaluate the potential added efficacy of this technique.

Trends in Dual Antiplatelet Therapy Use for Neurointerventional Procedures for the Management of Intracranial Aneurysms.

The use of periprocedural dual antiplatelet therapy (DAPT) has significantly evolved along with innovations in the endovascular management of intracranial aneurysms. Historically, aspirin and clopidogrel have been the most commonly employed regimen due to its safety and efficacy. However, recent studies highlight the importance of tailoring DAPT regimens to individual patient characteristics which may affect clopidogrel metabolism, such as genetic polymorphisms. In the present report, a systematic review of the literature was performed to determine optimal antiplatelet use with flow diverting stents, intracranial stents, intrasaccular devices, and stent-assisted coiling. Studies were analyzed for the number of aneurysms treated, DAPT regimen, and any thromboembolic complications. Based on inclusion criteria, 368 studies were selected, which revealed the increasing popularity of alternative DAPT regimens with the aforementioned devices. Thromboembolic or hemorrhagic complications associated with antiplatelet medications were similar across all medications. DAPT with ticagrelor, tirofiban, or prasugrel are effective and safe alternatives to clopidogrel and do not require enzymatic activation. Further clinical trials are needed to evaluate different antiplatelet regimens with various devices to establish highest-level evidence-based guidelines and recommendations.

Augmentation of flow diverter vessel wall apposition using the Comaneci device: case experience from a novel, off-label technique.

BACKGROUND: Flow diversion (FD) embolization of intracranial cerebral aneurysms is an increasingly common modality where treatment success depends on adequate vessel wall apposition of the device. This study aimed to investigate off-label use of the Comaneci device for augmenting vessel wall apposition in post-deployed flow diversion stents (FDS). METHODS: Over a 20- month period, all FD cases for the treatment of internal carotid artery (ICA) aneurysms were reviewed. Cases in which the Comaneci device was used to augment vessel wall apposition were analyzed. Data including patient demographics, case characteristics, and procedural outcomes were collected and analyzed as counts. RESULTS: From a total of 74 ICA FD cases, the Comaneci device was used to improve vessel wall apposition in 22 cases (29.7%) . Of these cases, 91% were female with a mean patient age of 64.9±11.3 years, and an average aneurysm size of 4.5±2.5 mm. Comaneci device deployment and retrieval was successful in all (100%) cases, with an average fluoroscopy time of 27.3±7.8 min, an average contrast usage of 25.8±13.2 mL, and an average radiation exposure of 915.1±320.8 mGy. Only two cases (9%) required subsequent balloon angioplasty after Comaneci deployment to improve vessel wall apposition throughout the FDS. CONCLUSION: Our experience with this technique demonstrates the feasibility of using the Comaneci device for augmentation of FDS vessel wall apposition with 100% success in the deployment and retrieval of the Comaneci device.

Medical Student Enrollment in a Voluntary Medical Innovation Course.

Background: There is an increasing need for medical innovators to help address the growing challenges within health care. Despite this, the rate of adoption of new medical innovation programs at the United States (US) medical schools has been slow. Existing literature explaining this slow rate of adoption is scant. We examined the rate of student enrollment in a voluntary medical innovation course during an unscheduled summer at our institution and the educational backgrounds of these enrollees. Methods: This mixed qualitative and quantitative survey study comprised consecutive surveys quantifying a two-stage sign-up process for a voluntary summer medical innovation course for Medical Doctorate (MD) candidates at the David Geffen School of Medicine. After a "General interest" survey, interested students completed an "Enrollment" survey to indicate enrollment, educational background, and open-ended comment about motivations for enrollment. Surveys were administered electronically via email listservs. Statistical methods included chi squared testing with statistical significance defined as p < 0.05. Findings: A total of 12% of UCLA Class of 2024 expressed an interest in participation in the program, and 10.3% ultimately enrolled. Enrollees were motivated primarily by the opportunity to learn about medical innovation (72%) and also shadow (28%). Enrollees were similar in undergraduate degrees and majors to the general medical student class and US MD candidate population. Conclusion: A lack of medical student willingness to participate may not underlie the observed slow rate of adoption of medical innovation programs at US MD programs given the observed high voluntary enrollment rate. Enrollee educational background did not differ significantly from non-enrollees or the broader US MD candidate population. Educators should be encouraged by these data to explore student willingness to participate in medical innovation education at their institutions.

Endoscope-Assisted Pedicled Maxillary Artery to Middle Cerebral Artery Bypass: An Anatomic Feasibility Study.

BACKGROUND: Extracranial to intracranial bypass is used to augment and/or replace the intracranial circulation for various pathologies. The superficial temporal artery is the mainstay donor for pedicled bypasses to the anterior circulation but can be limited by its variable size, low native flow rates, and potential scalp complications. Interposition grafts such as the radial artery or greater saphenous vein are alternatives but are sometimes limited by size mismatch, length needed to reach the extracranial circulation, and loss of inherent vascular elasticity. Interposition grafts between the maxillary artery (IMA) and middle cerebral artery (MCA) address these limitations. OBJECTIVE: To explore the feasibility of harvesting the IMA through an endoscopic transnasal, transmaxillary approach to perform a direct IMA to MCA bypass. METHODS: Combined transcranial and endoscopic endonasal dissections were performed in embalmed human cadavers to harvest the IMAs for intracranial transposition and direct anastomosis to the MCA. Donor and recipient vessel calibers were measured and recorded. RESULTS: A total of 8 procedures were performed using the largest and distal-most branches of the IMA (the sphenopalatine branch and the descending palatine branch) as pedicled conduits to second division of middle cerebral artery (M2) recipients. The mean diameter of the IMA donors was 1.89 mm (SD ± 0.42 mm), and the mean diameter of the recipient M2 vessels was 1.90 mm (SD ± 0.46 mm). CONCLUSION: Endoscopic harvest of the IMA using a transnasal, transmaxillary approach is a technically feasible option offering an excellent size match to the M2 divisions of the MCA and the advantages of a relatively short, pedicled donor vessel.

A novel ventriculoperitoneal shunt flow sensor based on electrically induced spatial variation in cerebrospinal fluid charge density.

Introduction: Ventriculoperitoneal (VP) shunts divert cerebrospinal fluid (CSF) out of cerebral ventricles in patients with hydrocephalus or elevated intracranial pressure (ICP). Despite high failure rates, there exist limited clinically viable solutions for long-term and continuous outpatient monitoring of CSF flow rate through VP shunts. We present a novel, low-power method for sensing analog CSF flow rate through a VP shunt premised on induced spatial electrical charge variation. Methods: Two geometric variants of the proposed sensing mechanism were prototyped: linear wire (P1) and cylindrical (P2) electrodes. Normal saline was gravity-driven through P1 and a commercially available shunt system in series. True flow rates were measured using a high-precision analytical balance. Subsequently, artificial CSF was driven by a programmable syringe pump through P2. Flow rate prediction models were empirically derived and tested. Sensor response was also assessed during simulated obstruction trials. Finally, power consumption per flow measurement was measured. Results: P1 (17 mm long) and P2 (22 mm long) averaged 7.2% and 4.2% error, respectively, in flow rate measurement from 0.01 to 0.90 mL/min. Response curves exhibited an appreciably flattened profile during obstruction trials compared to non-obstructed states. P2 consumed 37.5 µJoules per flow measurement. Conclusion: We propose a novel method for accurately sensing CSF flow rate through a VP shunt and validate this method at the benchtop with normal saline and artificial CSF over a board range of flows (0.01-0.90 mL/min). The sensing element is highly power efficient, compact, insertable into existing shunt and valve assemblies, and does not alter CSF flow mechanics.

The Role of Vancomycin Powder During Spinal Cord Stimulator Implantation: A Case Series and Review of the Literature.

OBJECTIVE: We examined the role of intrawound vancomycin powder as prophylaxis against postoperative surgical site infection (SSI) after spinal cord stimulator (SCS) implantation. METHODS: We performed a retrospective analysis of 153 consecutive patients who had undergone permanent SCS implantation surgery via open laminectomy between 2014 and 2020. We queried the patients' medical records for patient age, sex, relevant medical history, and whether intrawound vancomycin had been administered. We compared the rates of SSI (primary outcome) and seroma (secondary outcome) within 3 months after surgery between the vancomycin and no-vancomycin groups. Finally, we conducted multivariable logistic regression analyses to identify independent predictors of postoperative SSI or seroma. RESULTS: Of the 153 patients, 59% were women, and the average age was 65.4 years. Overall, 3 patients (2%) had developed an SSI: 2 (methicillin-resistant Staphylococcus aureus, Klebsiella) in the vancomycin group and 1 (methicillin-sensitive Staphylococcus aureus) in the no-vancomycin group. This difference in SSI rate between the 2 groups was insignificant (P = 0.73). Three seromas, all in the no-vancomycin group, accounted for a statistically significant difference in seroma formation between the 2 groups (P = 0.04). Multivariate logistic regression failed to identify any perioperative characteristics as independent predictors of postoperative SSI or seroma. CONCLUSIONS: Our experience suggests open laminectomy for SCS implantation surgery can be performed with a low postoperative SSI rate, with or without the use of powdered vancomycin. We found no evidence suggesting that the use of powdered vancomycin is unsafe or related to postoperative seroma formation. We failed to draw any definitive conclusions regarding its efficacy, despite referencing the largest single case series of SCS implantation to date.

Twisting: Incidence and Risk Factors of an Intraprocedural Challenge Associated With Pipeline Flow Diversion of Cerebral Aneurysms.

BACKGROUND: Pipeline Embolization Device (PED; Medtronic) "twisting" manifests with the appearance of a "figure 8" in perpendicular planes on digital subtraction angiography. This phenomenon has received little attention in the literature, requires technical precision to remediate, and has potential to cause ischemic stroke if not properly remediated. OBJECTIVE: To report incidence, risk factors, and sequelae of PED twisting and to discuss techniques to remediate a PED twist. METHODS: Case images were reviewed for instances of twisting from a prospectively-maintained, Institutional Review Board-approved cohort of patients undergoing flow diversion for cerebral aneurysm. RESULTS: From August 2011 to December 2017, 999 PED flow diverting stents were attempted in 782 cases for 653 patients. A total of 25 PED twists were observed while treating 20 patients (2.50%, 25/999). Multivariate analysis revealed predictors of twisting to be: Large and giant aneurysms (odds ratio (OR) = 9.66, P = .005; OR = 27.47, P < .001), increased PED length (OR = 1.14, P < .001), and advanced patient age (OR = 1.07, P = .002). Twisted PEDs were able to be remediated 75% of the time, and procedural success was achieved in 90% of cases. PED twisting was not found to be a significant cause of major or minor complications. However, at long-term follow-up, there was a trend towards poor occlusion outcomes for the cases that encountered twisting. CONCLUSION: Twisting is a rare event during PED deployment that was more likely to occur while treating large aneurysms with long devices in older patients. While twisting did not lead to major complications in this study, remediation can be challenging and may be associated with inferior occlusion outcomes.

Advances in endovascular aneurysm management: flow modulation techniques with braided mesh devices.

Flow diverters and flow disruption technology, alongside nuanced endovascular techniques, have ushered in a new era of treating cerebral aneurysms. Here, we provide an overview of the latest flow modulation devices and highlight their clinical applications and outcomes.

Aspirin Monotherapy in Flow Diversion of Selected Internal Carotid Artery Aneurysms.

BACKGROUND: Dual antiplatelet therapy has been adopted as the standard of care for intracranial stenting, including flow diversion of cerebral aneurysms, to reduce the risk of acute and delayed ischemic complications. CASE DESCRIPTION: This is a report of 2 cases in which patients who underwent flow diversion of unruptured internal carotid artery aneurysms were treated with aspirin monotherapy. Neither patient tolerated dual antiplatelet therapy, one because of nosebleeds due to hereditary hemorrhagic telangiectasia and one because of an unnamed bleeding disorder. The lesions-a previously coiled, recanalizing dorsal internal carotid artery aneurysm and a small superior hypophyseal aneurysm-were each treated with a single Pipeline Flex embolization device and were completely occluded with normal-appearing parent vessel on 12-month follow-up digital subtraction angiography. CONCLUSIONS: This is the first report of patients electively treated with flow diversion using Pipeline Flex embolization device on aspirin monotherapy in the literature.

Flow diversion covering the M1 origin as a last resort.

INTRODUCTION: Internal carotid artery termination (ICAT) and proximal A1 aneurysms can be challenging for open surgical clipping or endovascular coiling. Treatment with flow diversion covering the middle cerebral artery (MCA), an end vessel supplying a terminal circulation, has not been reported. METHODS: A prospective, Institutional Review Board-approved database was analysed for patients with pipeline embolisation device (PED) placement from the anterior cerebral artery (ACA) to the ICA during cerebral aneurysm treatment. RESULTS: Nine cases were identified, including five proximal A1, three posterior communicating artery and one ICAT aneurysm locations. Average aneurysm size was 8.3 mm (range 3-17), with 67% saccular and 78% right-sided. Primary indication for treatment was significant dome irregularity (44%), recurrence or enlargement (33%), underlying collagen vascular disorder (11%) and traumatic pseudoaneurysm (11%). Preservation of the ipsilateral ACA (with PED placed in A1) was performed when the anterior communicating artery (67%) or contralateral A1 (33%) were absent on angiography. Adjunctive coiling was done in four cases (44%). There was one major stroke leading to mortality (11%) and one minor stroke (11%). Clinical follow-up was 27 months on average. Follow-up digital subtraction angiography (average interval 15 months) showed complete aneurysm obliteration (88%) or dome occlusion with entry remnant (12%). The jailed MCA showed minimal or mild delay (primarily anterograde flow) in 75% of cases and significant delay (reliance primarily on ACA and external carotid artery collaterals) in 25%. CONCLUSIONS: Covering the MCA with a flow diverting stent should be reserved for select rare cases. Strict attention to blood pressure augmentation during the periprocedural period is necessary to minimise potential ischaemic compromise.

Tandem cervical carotid stenting for stenosis with flow diversion embolisation for the treatment of intracranial aneurysms.

BACKGROUND: An estimated 2%-3% of the population harbour an intracranial aneurysm. Concomitant atherosclerotic cervical carotid disease is not uncommon. The management of these two entities remains a challenge within the field. CASE PRESENTATION: We report a single case of concomitant carotid stenosis and two ipsilateral unruptured intracranial aneurysms treated with a single-staged cervical carotid stenting and cerebral aneurysm embolisation with the Pipeline embolisation device. DISCUSSION: No consensus currently exists to guide endovascular treatment of intracranial aneurysms associated with asymptomatic ipsilateral stenosis. Here, we present a case of asymptomatic moderate carotid stenosis with two ipsilateral intracranial aneurysms and suggest carotid artery stenting takes procedural priority over aneurysm embolisation in single-stage treatment. The rationale for the sequence of neurointerventions is based on the tracking a robust distal access system beyond a stenotic proximal carotid lesion and stabilisation of the ulcerated plaque to avoid thromboembolic complications associated with plaque irritation during aneurysm embolisation. Additional cases and longer follow-up will be needed to further assess the efficacy of this technique.

Tiny Pipes: 67 Cases of Flow Diversion for Aneurysms in Distal Vessels Measuring Less Than 2.0 mm.

BACKGROUND: Flow diversion is increasingly used for off-label treatments of distal circulation aneurysms. Reports of use in sub-2.0-mm vessels are scant. METHODS: A prospectively collected, institutional review board-approved cerebral aneurysm database was reviewed to identify patients who underwent flow diversion with a 2.5-mm diameter Pipeline embolization device. RESULTS: Sixty-seven aneurysms were treated in 67 procedures (66 [99%] successful, 64 [96%] single device, 2 [3%] with 2 devices) in 57 patients. Average age was 56 years and 60% were female. Aneurysm location was 51 (76%) anterior cerebral artery, 14 (21%) middle cerebral artery, and 2 (3%) posterior cerebral artery. Aneurysm size was 4.1 ± 3.0 mm (1-20 mm). Safety outcomes included 3 major strokes (4.5%) resulting in permanent neurologic deficit (modified Rankin Scale score 6,4,4), including 1 mortality (1.5%). Acute stent thrombosis was observed intraprocedurally or within 24 hours of each stroke. There were 2 small-volume (<10 cm3, 40 cm3) dependent intracerebral hemorrhage (3.0%) that resolved without permanent neurologic deficit. For effectiveness, 71% of patients underwent follow-up angiography. Complete occlusion was achieved by 88% at 6 months, 86% at 12 months, and 89% at last follow-up. A slight vessel diameter reduction was apparent on average 6.9 months after the procedure, which was statistically significant at the proximal (P = 0.001) but not distal (P = 0.317) device end. Preoperative average parent vessel diameter was 1.9 mm proximally (range, 1.1-2.6 mm) and 1.7 mm distally (range, 1.0-2.3 mm) of the Pipeline embolization device. Follow-up average vessel diameter was 1.7 mm proximally (range, 0.7-2.4 mm) and 1.6 mm distally (range, 0.6-2.1 mm). Flow delay associated with vessel diameter reduction occurred once. There were no cases of asymptomatic vessel occlusion. CONCLUSIONS: Flow diversion can be safe and effective for aneurysms originating from vessels <2.0 mm in diameter. Heightened vigilance for the prevention and management of acute stent and vessel thrombosis is warranted in these cases.

Flow Diversion of Posterior Circulation Cerebral Aneurysms: A Single-Institution Series of 59 Cases.

BACKGROUND: Posterior circulation cerebral aneurysms are at higher risk of rupture and are more symptomatic than those in the anterior circulation. Existing treatments carry significant morbidity. Early reports of flow diversion for posterior circulation aneurysms have suggested high complication and low occlusion rates. OBJECTIVE: To report safety and efficacy of flow diversion with the pipeline embolization device (ev3, Medtronic Inc, Dublin, Ireland) for aneurysms located throughout the posterior circulation. METHODS: A prospective, institutional review board-approved database was analyzed for all patients with posterior circulation aneurysms treated by flow diversion at our institution. RESULTS: Fifty-nine embolization procedures were performed on 55 patients. Average aneurysm size was 9.4 mm. Morphology was saccular (45%), fusiform (29%), or dissecting/pseudo-aneurysms (25%). Sixty-two percent of aneurysms arose along the vertebral artery. There were 7 mid-basilar (13%) and 7 basilar apex (13%) aneurysms. Procedural success was 98%; 1 Pipeline embolization device was placed in 85%; and coiling was performed in 17% of cases. There were 5 major complications (8%), all strokes. Patients with major stroke had modified Rankin Scale score at last follow-up of 1, 3, 4, 6, and 6 (2 mortalities). There were zero intracerebral or subarachnoid hemorrhages. No variable predicted complications on univariate or multivariate analysis. Follow-up digital subtraction angiography was performed for 43 patients (78%). Complete occlusion was 68% at 6 mo and 78% at 12 mo. Average follow-up was 11.8 mo. Fusiform or dissecting morphology and large or giant aneurysm size were predictors of aneurysm persistence at 6 mo on multivariate logistic regression. CONCLUSION: This is a large single-institution series of Pipeline (Medtronic Inc) for posterior circulation aneurysms and demonstrates acceptable safety and effectiveness in these challenging cases.

Precision of VerifyNow P2Y12 Assessment of Clopidogrel Response in Patients Undergoing Cerebral Aneurysm Flow Diversion.

BACKGROUND: Dual antiplatelet therapy (DAT), most commonly with aspirin and Clopidogrel, is the standard of care for intracranial stenting, including flow diversion. Clopidogrel response varies by individual. OBJECTIVE: To investigate the real-world precision of VerifyNow P2Y12 assessment (Accumetrics, San Diego, California) of Clopidogrel response. METHODS: Using a prospectively-collected, IRB-approved cerebral aneurysm database 643 patients were identified who were treated with the Pipeline embolization device from 2011 to 2017. Patients with multiple P2Y12 assays drawn within a 24-h window were identified. A single patient could contribute multiple, independent sets. Levels drawn before a 5-d course of DAT and patients who received alternative antiplatelet agents were excluded. Therapeutic range was defined as platelet reaction units (PRU) 60-200. RESULTS: A total of 1586 P2Y12 measurements were recorded; 293 (46%) patients had more than one assay. One hundred forty (22%) patients had multiple P2Y12 measurements within 24 h. These patients accounted for 230 independent 24-h sets. The average P2Y12 fluctuation across all sets was 35 points; the 25th, 50th, and 75th percentiles were 12, 26, and 48 points, respectively. Of the 230 24-h sets of P2Y12 assays, 76% remained within their original therapeutic category: 100 (43%) all therapeutic, 54 (23%) all hypo-responsive, and 21 (9%) all hyper-responsive. Twenty-four percent of patients fluctuated between therapeutic categories when multiple P2Y12 assessments were drawn within a 24-h period: 29 (13%) between hypo-response and therapeutic, 23 (10%) between hyper-response and therapeutic, and 3 (1%) between hypo-response and hyper-response. CONCLUSION: Our experience suggests P2Y12 is an often-imprecise measure, and this should be considered when utilizing P2Y12 levels for clinical decisions.

Pipeline Embolization for Salvage Treatment of Previously Stented Residual and Recurrent Cerebral Aneurysms.

INTRODUCTION: This study assessed the safety and effectiveness of the Pipeline embolization device (PED) for persistent and recurrent aneurysms previously treated with either a vascular reconstruction device (VRD) or a flow diverter (FD). METHODS: A prospective, IRB-approved database was analyzed for patients treated with PED for aneurysms previously treated with a stent. RESULTS: Twenty procedures were performed on 18 patients, 11 with prior FD, 7 with VRD, and 2 previously treated with both. Overall, 15 aneurysms were saccular (75%), and size was 13.5 ± 7.6 mm. Location was internal carotid artery (ICA) in 14 cases (70%) and posterior circulation in 6 cases (30%). Average prior treatments were 1.7. Previously FD cases were re-treated at an average of 18.1 months from most recent treatment. Each case used 1 device, 82% with distal coverage and 82% with proximal coverage of prior stent. Balloon remodeling was performed in 3 cases (27%) and no in-stent thrombosis was observed. Previously VRD stent-coiled cases were re-treated at an average of 87.5 months. These cases used on average 1.9 devices, 89% with distal and 100% proximal coverage. Adjunctive coiling was performed in 1 case (11%), balloon remodeling in 5 cases (56%), and 2 cases (28%) developed thrombosis that resolved with abciximab. Re-VRD cases were longer (59.1 vs. 33.7 min, p = 0.02) than re-FD. Angiographic follow-up was available for 16 cases (80%). In re-FD, occlusion was complete in 56% and partial progressive in 33% at 17.1 months digital subtraction angiography. In re-VRD, occlusion was complete in 57% and partial progressive in 27% at 8.1 months. Two complications occurred (10%), including one asymptomatic cervical ICA occlusion and one stent occlusion with associated mortality (5%). Clinical follow-up was 17.8 months on average (range 0.5-51.9). CONCLUSIONS: Salvage flow diversion for previously stented aneurysms is technically challenging but offers good prospects of aneurysm obliteration with acceptable complication rates.