Pipeline Embolization Device Deployment Research Articles

Predictors of occlusion, long-term outcomes, and safety in a cohort of 674 aneurysms treated with the Pipeline embolization device.

By providing a more physiological approach to the treatment of intracranial aneurysms, the Pipeline embolization device (PED) has revolutionized the endovascular treatment of aneurysms. Although there are many flow diverters on the market, the authors report their experience with the PED, the first flow diverter to be approved by the Food and Drug Administration. They aimed to assess the efficacy and safety of PED flow diversion for the treatment of a wide range of aneurysms, as well as to look at factors affecting occlusion. This is a retrospective study of a prospectively maintained database of patients treated with the PED between January 2011 and December 2019. Charts were reviewed for patient, aneurysm, and procedure characteristics. The primary outcomes of interest were complication rates, occlusion outcomes (O'Kelly-Marotta grading scale), and functional outcomes (modified Rankin Scale [mRS]). Secondary outcomes included predictors of incomplete occlusion at 6 and 24 months of follow-up. The study cohort included 581 patients with 674 aneurysms. Most aneurysms (90.5%) were in the anterior circulation and had a saccular morphology (85.6%). Additionally, 638 aneurysms (94.7%) were unruptured, whereas 36 (5.3%) were acutely ruptured. The largest mean aneurysm diameter was 8.3 ± 6.1 mm. Complications occurred at a rate of 5.5% (n = 32). The complete occlusion rate was 89.3% at 24 months' follow-up, and 94.8% of patients had a favorable neurological outcome (mRS score 0-2) at the last follow-up. On multivariate analysis, predictors of incomplete aneurysm occlusion at 6 months were hypertension (OR 1.7, p = 0.03), previous aneurysm treatment (OR 2.4, p = 0.001), and increasing aneurysm neck diameter (OR 1.2, p = 0.02), whereas a saccular morphology was protective (OR 0.5, p = 0.05). Predictors of incomplete occlusion at 24 months were increasing aneurysm neck diameter (OR 1.2, p = 0.01) and previous aneurysm treatment (OR 2.3, p = 0.01). The study findings are corroborated by those of previous studies and trials. The complete occlusion rate was 89.3% at 24 months' follow-up, with 94.8% of patients having favorable functional outcomes (mRS score 0-2). Aneurysm treatment before PED deployment and an increasing aneurysm neck diameter increase the risk of incomplete occlusion at 6 and 24 months.

Retreatment with a pipeline embolization device for recanalized aneurysms following stent-assisted coiling embolization.

Flow diverters have emerged as viable alternatives for the retreatment of recanalized aneurysms following stent-assisted coiling embolization. In this study, we aim to present our experience of retreatment for such aneurysms using the pipeline embolization device (PED). This case series presents a retrospective single-center analysis of patients with recanalized aneurysms who underwent retreatment using the PED between July 2019 and April 2023, subsequent to stent-assisted coiling embolization. The study includes five female patients, whose relevant clinical data were recorded. All patients had aneurysms located in the internal carotid artery, comprising two blood blister-like aneurysms and two giant aneurysms. Prior to the retreatment, two LVIS stents, two enterprise stents, and one solitaire stent were implanted. Among the five patients, one experienced a fatal post-operative subarachnoid hemorrhage, while two patients achieved complete embolization, and another patient achieved near-complete embolization during the last follow-up. Furthermore, one patient faced challenges during the placement of the PED and was unable to achieve successful deployment. We propose four overlapping relationships between a newly implanted PED and a previously deployed stent: (1) PED covering only the proximal end of the previous stent, (2) PED covering only the distal end of the previous stent, (3) PED covering both the proximal and distal ends of the previous stent, and (4) PED deployed within the previous stent. Antiplatelet therapy at our center involved daily dual therapy with aspirin (100 mg/day) and clopidogrel (75 mg/day) for at least 5 days before PED placement. Intra-arterial bolus administration of tirofiban (5 mcg/kg) was administered during or immediately after PED deployment, followed by a maintenance dose of 0.08 mcg/kg/min IV infusion for at least 24-48 h if necessary. Postprocedural dual antiplatelet therapy included clopidogrel (75 mg/day) for 6 months and aspirin (100 mg/day) for 12 months. The findings of this study support the efficacy of the PED for the retreatment of recanalized aneurysms following stent-assisted coiling embolization.

Abstract Number ‐ 140: Transcranial Doppler Emboli Monitoring for Stroke Prevention after Flow Diversion: A Single Center Experience

Introduction Following the favorable clinical and radiographical results of flow diversion, its use has continually expanded for the treatment of complex intracranial aneurysms. The high metal surface of flow diverters (FD) increases the risk of thromboembolic complications. Current emboli monitoring data after FD placement is limited. Transcranial doppler (TCD) offers a non‐invasive evaluation of microembolic signals and might be a valuable tool to prevent ischemic complications. We evaluated the rate of embolic signals and their management after FD implantation. Methods We performed a retrospective, single‐center evaluation of adult patients who underwent a FD procedure with the Pipeline Embolization Device (PED) for unruptured intracranial aneurysms between 2012 and 2016. Covariates included patient demographics, comorbidities, aneurysm characteristics, procedure characteristics, and post‐procedure TCD emboli monitoring (immediate and >12 hours post‐operative). TCD emboli signals were classified as positive (< 15 microembolic signals) and strongly positive (>15 signals). The primary outcome was the rate of symptomatic stroke at 2 and 12 weeks in these patients. Results 105 patients with 132 aneurysms were analyzed. Mean age was 59.7 years, and 78% were females. Mean aneurysm size was 7.8 ± 6.4 mm. Most of them were located in the paraclinoid region (40%). Two PEDs were implanted in 12 (11%) cases and adjunctive coiling was performed in 15 (14%) cases. Microemboli were detected in 11.4% of cases (12/105 patients) after PED deployment. In 5/12 patients, the emboli resolved upon repeat testing with no intervention. In 6/12 patients, further heparinization, additional clopidogrel administration, or change in antiplatelet agents were needed. These treatments reduced the microembolic events. In 1 patient who was clopidogrel‐resistant and a ticagrelor super‐responder, mechanical thrombectomy was necessary due to acute in‐stent thrombosis. There were no symptomatic strokes at 2 and 12 weeks. Conclusions TCD emboli monitoring can be a powerful non‐invasive tool for the early identification and prevention of thromboembolic events after FD implantation. Early detection of microembolic signals offers the possibility to modify postoperative management, avoid silent emboli, and potentially avoid symptomatic strokes.

Initial experience with Pipeline embolization of intracranial pseudoaneurysms in pediatric patients.

Flow-diverting devices have been used successfully for the treatment of complex intracranial vascular injuries in adults, but the role of these devices in treating iatrogenic and traumatic intracranial vascular injuries in children remains unclear. The authors present their experience using the Pipeline embolization device (PED) for treating intracranial pseudoaneurysms in children. This single-center retrospective cohort study included pediatric patients with traumatic and iatrogenic injuries to the intracranial vasculature that were treated with the PED between 2015 and 2021. Demographic data, indications for treatment, the number and sizes of PEDs used, follow-up imaging, and clinical outcomes were analyzed. Six patients with a median age of 12 years (range 7-16 years) underwent PED placement to treat intracranial pseudoaneurysms. There were 3 patients with hemorrhagic presentation, 2 with ischemia, and 1 in whom a growing pseudoaneurysm was found on angiography. Injured vessels included the anterior cerebral artery (n = 2), the supraclinoid internal carotid artery (ICA, n = 2), the cavernous ICA (n = 1), and the distal cervical ICA (n = 1). All 6 pseudoaneurysms were successfully treated with PED deployment. One patient required re-treatment with a second PED within a week because of concern for a growing pseudoaneurysm. One patient experienced parent vessel occlusion without neurological sequelae. Use of the PED is feasible for the management of iatrogenic and traumatic pseudoaneurysms of the intracranial vasculature in children, even in the setting of hemorrhagic presentation.

Rupture of an adjacent cerebral aneurysm following the deployment of a Pipeline embolization device: illustrative case.

BACKGROUNDAlthough the Pipeline embolization device (PED) is effective for intracranial aneurysm treatment, its impact on the surrounding vascular structure is unknown.OBSERVATIONSA 71-year-old woman was incidentally found to have a simultaneous large posterior communicating artery aneurysm and an ipsilateral small anterior choroidal artery aneurysm. She underwent flow diversion therapy for both aneurysms with a PED, but the distal shortening of the PED after deployment led to the exposure of the anterior choroidal artery aneurysm. Follow-up angiography revealed complete obliteration of the posterior communicating artery aneurysm, but the anterior choroidal artery aneurysm remained. Three years after the endovascular surgery, the patient experienced a subarachnoid hemorrhage due to the rupture of the anterior choroidal artery aneurysm. Retrospective analysis of angiographic images revealed a change in the vascular geometry surrounding the ruptured aneurysm after PED deployment; this was further accompanied by an increase in the flow velocity inside the aneurysm.LESSONSBecause PED use might induce the adverse effects on the adjacent uncovered aneurysm by changing the vascular geometry and hemodynamic stress, a cautious therapeutic strategy, such as proper placement of the stent and using a longer and appropriate-sized PED, should be chosen when deploying the PED.

Pattern of changes in cross sectional area of arterial branches after jailing with pipeline embolization device: beyond parent neck artery patency

ObjectiveThe Pipeline-Embolization-Device (PED) has been used increasingly for intracranial-aneurysms. Despite the high-patency-rate of jailed branches following PED deployment, little is known about changes in these vessels size. This study measured change in size after PED. MethodsThis retrospective-study screened a database of 183-consecutive-patients treated with PED (07/2011-07/2017) across inclusion criteria. We included patients in whom the ophthalmic artery (OA) and/or the posterior communicating artery (PComA) were jailed by the PED. MRA was used to calculate change in cross-sectional-area (CSA) of these vessels. 29 patients who had MRA before and after treatment were included in the study. The CSA was measured automatically using Syngo®.via-software at fixed points along the analyzed vessels. After exclusion of low-quality and software non-capturable MRA-images, 16 OA and 23 PComA were included in the final analysis. Statistical Package for Social Sciences was used for analysis. ResultsThe mean CSA of PComA, P1-segement of posteriror-cerebral-artery (P1-PCA), and OA was 3.3 ± 1.3, 4.1 ± 1.2, and 3.2 ± 0.9 mm2 at baseline and 1.9 ± 1.4, 4.3 ± 1.2, and 3.1 ± 0.7 mm2 at follow-up, respectively. The average follow-up was approximately 26 months. While the decrease in CSA of PComA was statistically significant, the increase in P1-PCA CSA was not. The change in OA CSA was not statistically significant. ConclusionJailing PComA with a PED resulted in a statistically significant decrease in PComA CSA and a statistically non-significant increase in ipsilateral P1 CSA. No statistically significant change in the CSA of OA was noted. Changes might be due to a balance between flow demand through the jailed ostium and presence of collateral flow.

Pipeline Embolization Device for the Treatment of Unruptured Intracranial Dissecting Aneurysms.

Background: Intracranial dissecting aneurysms (IDAs) are rare but pose significant challenges to treatment. The pipeline embolization device (PED) has been demonstrated to be an effective treatment option with excellent outcomes. Herein, we report our experience with patients treated with the PED for unruptured IDAs.Methods: We retrospectively reviewed our hospital database and identified patients who were treated with PEDs for unruptured IDAs between March 2016 and September 2020. Data including demographics, clinical presentation, aneurysm characteristics, procedural details, intra- or peri-procedural complications, and follow-up details were collected.Results: Eighty patients (61 men, 76.25%) were treated with PED for unruptured IDAs. The most common symptoms were headache (34, 42.5%), dizziness (29, 36.25%), and nausea or vomiting (15, 18.75%). Of these patients, 73 had one aneurysm, and seven harbored two aneurysms. All of them achieved successful PED deployment. Six patients experienced intra- or peri-procedural complications including perforator artery occlusion, thromboembolic, hemorrhagic events, and falling of the stent into the aneurysm sac. Follow-up with digital subtractive angiography was available for 29 patients with a median of 6 months, and 28 (96.56%) patients had aneurysm occlusion. Late thrombosis occurred in four patients, and two of them had unfavorable outcomes. Clinical follow-up showed that a favorable clinical outcome was achieved in 76 (95%) patients, and the mortality rate was 3.75%.Conclusion: Treating unruptured IDAs is safe and effective with long-term favorable clinical and angiographic outcomes. However, the complications of this treatment should be noted. Careful selection of appropriate patients and individualized antiplatelet therapy might be needed.

Safety Evaluation and Flow Modification in the Anterior Cerebral Artery after Pipeline Embolization Device Deployment across the Internal Carotid Artery Terminus.

Method The clinical and imaging data of PEDs in the postmarket multicenter registry study (PLUS) in China were retrospectively analyzed, and patients were divided into two groups on the basis of the follow-up angiographic results: group 1 (no significant change in A1 blood flow) and group 2 (A1 occlusion or decreased blood flow). We collected patients' baseline data and evaluated the following imaging indicators: diameter and ratio of bilateral A1, M1, and internal carotid artery (ICA) vessels before stenting and the ratio of the PED size (sPED) to the ipsilateral ICA (I-ICA) diameter on the implantation side. Results A total of 1171 patients were included, of whom 48 met the inclusion criteria (17 in group 1 and 31 in group 2). In group 2, three patients experienced neurological deterioration at follow-up. From the univariate analysis of outcomes, single PED without coils, incomplete aneurysm occlusion (IAO), maximum aneurysm diameter, aneurysms involving the ICA bifurcation (ICAb), and large sPED/I-ICA diameter ratio were included in the multivariate analysis (P < 0.20). The multivariate regression analysis results showed that the ratio of sPED/I-ICA diameter was the factor influencing A1 vessel occlusion. The area under the ROC curve was 73.2%. When the sPED/I-ICA diameter ratio was 1.14, sensitivity was 70.6%, and specificity was 77.4%. Conclusion When an oversized PED is placed from M1 to the ICA, the higher porosity formed at the covered A1 orifice is conducive to maintaining stable A1 blood flow and reducing the risk of A1 vessel occlusion. This trial is registered with ClinicalTrials.gov identifier: NCT03831672.

Flow Diversion for Intracranial Aneurysms Beyond the Circle of Willis.

Background: Few reports have shown the therapeutic outcomes of flow diversion (FD) for intracranial aneurysms beyond the circle of Willis, and the efficacy of this technique remains unclear.Materials and methods: A retrospective study was performed on 22 consecutive patients, diagnosed with intracranial aneurysms beyond the circle of Willis, and treated with pipeline embolization device (PED) (Medtronic, Irvine, California, USA) between January 2015 and December 2019.Result: The 22 patients were between 16 and 66 years old (mean 44.5 ± 12.7 years), and six patients were male (27.3%, 6/22). Twenty-two patients had 23 aneurysms. The 23 aneurysms were 3–25 mm in diameter (12.2 ± 7.1 mm on average). The diameter of the parent artery was 1.3–3.0 mm (2.0 ± 0.6 mm on average). The 23 aneurysms were located as follows: 17 (73.9%, 17/23) were in the anterior circulation, and 6 (26.1%, 6/23) were in the posterior circulation. PED deployment was technically successful in all cases. Two overlapping PEDs were used to cover the aneurysm neck in 3 cases. One PED was used to overlap the two tandem P1 and P2 aneurysms. Other cases were treated with single PED. Coil assistance was used to treat 7 aneurysms, including 4 recurrent aneurysms and 3 new cases requiring coiling assistance during PED deployment. There were no cases of complications during PED deployment. All patients were available at the follow-up (mean, 10.9 ± 11.4 months). All patients presented with a modified Rankin Score (mRS) of 0. During angiographic follow-up, complete embolization was observed in 22 aneurysms in 21 patients, and one patient had subtotal embolization with the prolongation of stasis in the arterial phase.Conclusion: PED deployment for intracranial aneurysms beyond the circle of Willis is feasible and effective, with high rates of aneurysm occlusion.

Triggering of Carotid Sinus Reflex during Deployment of the Flow-diverter Device.

The carotid sinus reflex (CSR) is a rare complication of the Pipeline Embolization Device (PED) deployment. No study has assessed the potential risk factors in a case series. The purpose of this study was to examine CSR triggering during PED deployment. Thirty-seven consecutive patients who underwent PED deployment were included. All procedures were performed under local anesthesia with mild sedation. We retrospectively analyzed patient characteristics, PED deployment time, and vital signs during the procedure. The vital signs included the pulse rate (PR) and systolic blood pressure (SBP) obtained at three timepoints (pre-deployment, during deployment, post-deployment). We examined the triggering of the CSR during PED deployment by comparing the vital signs at the three timepoints. Moreover, risk factors for CSR were analyzed with univariate analysis. The patients’ average age was 66.3 years. The average size of the aneurysm was 18.0 mm. Six patients (16.2%) showed a decline in the SBP or PR defined as CSR. One patient had a transient cardiac arrest and two had severe transient bradycardia. Deployment into the ophthalmic segment of the internal carotid artery (C2 segment) aneurysm (p = 0.022), prolonged PED deployment time more than 14.5 minutes (p = 0.005), and an acute angle of the anterior genu less than 51.5 degrees (p = 0.005) were risk factors in triggering CSR. CSR may be triggered during PED deployment under local anesthesia with mild sedation. Deployment to the C2 segment aneurysm, prolonged PED deployment time, and an acute angle of the anterior genu were associated with CSR triggering.

Transradial access for flow diversion of intracranial aneurysms: Case series.

Transradial access for neurointerventions offers advantages of fewer access-site complications, reduced procedure time, and greater patient comfort over transfemoral access. Data about transradial access for flow diversion are limited. We share our early experience with transradial access for flow diversion in a relatively large case series. Consecutive patients who underwent Pipeline embolization device (Medtronic) deployment via transradial access were included in the study, irrespective of location and laterality of the intracranial aneurysm. The cases were performed between July 2016 and October 2019. Demographics, aneurysm characteristics, and procedure-related details (including catheter systems used) were recorded and statistically evaluated. Thirty-five transradial flow diversion procedures were attempted in 32 patients, of which 33 procedures were successful. In two cases involving left common carotid artery and internal carotid artery access, guide catheter herniation into the aortic arch led to abandonment of transradial access in favor of transfemoral access. The most common aneurysm locations in the transradial access procedures were the posterior communicating artery (n = 7), ophthalmic artery (n = 7), and superior hypophyseal artery (n = 7). Most transradial access procedures (66.7%) were performed using a biaxial catheter system. 6-French Benchmark (Penumbra) and Phenom 27 (Medtronic) were the most commonly utilized guide- and microcatheters, respectively. One patient had intraprocedural subarachnoid hemorrhage. No access-site complications occurred. This study demonstrates safety and feasibility of transradial access for Pipeline embolization device deployment and shows the versatility of this approach for different catheter systems. Tortuosity and acute angulation of the left common carotid artery and internal carotid artery were associated with approach failure.

The POP (Pull on Pipe) Maneuver: A Technical Note for Rescuing a Prolapsed Pipeline Device

Background: Flow diverters have revolutionized the treatment of large aneurysms. However, prolapse of the device into the aneurysm is a known complication that may have fatal consequences. Case: We present a case of a 21-year-old male with a giant aneurysm located in the cavernous segment of the right internal carotid artery. After Pipeline Embolization Device (PED) deployment, while retrieving the PED wire, the proximal end of the stent shortened, resulting in prolapse of the device into the aneurysm. We utilized the Pull on Pipe (POP) maneuver, characterized by the deployment of a second PED inside the lumen of the prolapsed device and gentle traction to restore the initial flow diverter into its proper position. The maneuver also allows for the immediate deployment of the second PED to improve proximal purchase and overall construct stability. Conclusion: The POP maneuver is a novel strategy for salvaging herniated flow diverters and establishing a more stable PED construct.

Risk factor analysis of ischemic stroke following flow diverter placement for paraclinoid aneurysms

Objective To evaluate risk factors for acute ischemic stroke following treatment of paraclinoid aneurysms using flow diverters. Methods Between September 2015 and July 2018, 205 consecutive patients with 229 paraclinoid aneurysms were treated with Pipeline embolization device (PED) at Department of Interventional Neuroradiology, Beijing Tiantan Hospital, Capital Medical University. The aneurysm size and parent artery size were measured. According to the length, proximal and distal diameter of the parent artery, appropriate size of PED was deployed with or without coiling. Various potential risk factors associated with acute ischemic stroke following PED treatment were documented. Univariate and multivariate logistic regression analyses were applied to identify risk factors. Results Among the 205 patients with 229 paraclinoid aneurysms, 110 aneurysms were treated by PED and 119 aneurysms received PED with coiling, all PED were delivered and implanted successfully. Eighteen (8.8%) patients with 20 aneurysms had acute ischemic stroke after PED deployment. Univariate analysis suggested that ADP inhibition, high MA-ADP value, clopidogrel non-response, application of complex intraoperative techniques, and long operation time were associated with the acute ischemic stroke following PED treatment (all P<0.05). Further multivariate logistic regression analysis showed the clopidogrel non-response (OR=6.161, 95% CI: 1.480-25.649, P=0.012), application of complex intraoperative techniques (OR=8.405, 95% CI: 1.437-49.146, P=0.018) and operation time (OR=1.011, 95% CI: 1.002-1.020, P=0.022) were independent factors for acute ischemic stroke following PED treatment. Conclusions Clopidogrel non-response, application of complex intraoperative techniques and long operation time may increase the risk of ischemic events. Key words: Intracranial aneurysm; Stroke; Factor analysis, statistical; Flow diverter; Paraclinoid

Is Contrast Stasis After Pipeline Embolization Device Deployment Associated with Higher Aneurysm Occlusion Rates?

To assess the association of degree of contrast stasis in intracranial aneurysms (IAs) immediately after Pipeline embolization device (PED; Medtronic, Dublin, Ireland) deployment with 6- and 12-month angiographic occlusion rates. This retrospective cohort study included consecutive patients undergoing PED deployment for saccular IA treatment at a large-volume cerebrovascular center over a 4-year 9-month period. Angiographic images obtained immediately after PED deployment were graded according to amount of intra-aneurysmal contrast flow during the late venous phase: 0= no stasis; 1= <50% contrast stasis; 2= 50%-75% stasis; and 3= >75%-99% stasis. Follow-up occlusion rates were determined by digital subtraction angiography, computed tomographic angiography, or magnetic resonance angiography. The study included 119 patients in whom 182 PEDs were deployed to treat 141 aneurysms. A single PED was deployed in 105 (74.5%) aneurysms. The internal carotid artery was the commonest aneurysm site (119 [85%]). Fifty-two (36.9%) aneurysms were grade 0; 33 (23.4%) were grade 1; 46 (32.6%) were grade 2; and 10 (7.1%) were grade 3 immediately post-treatment. A 6-month follow-up angiogram available for 101 aneurysms showed complete occlusion (no flow into the aneurysm) in 74 (73.3%) aneurysms. A 12-month follow-up study available for 132 aneurysms showed complete occlusion in 79.5%. At last follow-up, occlusion rates were not significantly different for different contrast stasis grades (P= 0.60). Mean angiographic follow up for all IAs was 23v±v17.7 months. IA size, sex, age, and smoking were not significant predictors of occlusion. The degree of aneurysm contrast stasis immediately after PED deployment is not statistically associated with 6- and 12-month angiographic occlusion rates.

P.034 Evaluation of modeling software for deployment of Pipeline stents in the endovascular treatment of intracranial aneurysms

Background: Flow diversion is an established endovascular method for the treatment of intracranial aneurysms. The Pipeline Embolization Device (PED) remains the only FDA-approved stent available in USA and Canada since 2011. Stent position plays an important role in determining long-term success. The Leonardo Workstation(Siemens) is used for planning the ideal stent size and post-deployment destination. This first-ever study evaluates the accuracy of modeling software in predicting PED location post-deployment. Methods: 48 PED-assisted cases were performed 2012-2018 at the University of Alberta Hospital. 20 fit our preliminary inclusion criteria (single stents, simple anatomy). The proximal and distal landing zones were used to model the ideal stent using Leonardo. Accuracy was measured by comparing the Leonardo-predicted stent length vs known length. Results modeling against the dimensions predicted by AngioSuite, an app-based interface designed for use in the planning stages. Results: Leonardo workstation is accurate within 5mm at predicting final length for stents oversized by ≥0.25 cm. The predicted difference by Leonardo workstation &amp;amp; AngioSuite did not demonstrate statistical significance (P=0.36, P=0.24 respectively). Conclusions: Current angiographic planning tools are accurate at predicting PED deployment within 5mm. Complex vascular anatomy and deployment of multiple stents make prediction challenging. Analysis of these complex cases is currently underway.

Hemodynamic Fate of the Precommunicating Anterior Cerebral Artery Is Predicted by Vessel Dominance After Pipeline Embolization Device Deployment Across the Internal Carotid Artery Terminus

The Pipeline embolization device (PED) is commonly used for the treatment of distal internal carotid artery (ICA) aneurysms, which often require placing the stent across the origin of the precommunicating segment of the anterior cerebral artery (ACA-A1). We sought to characterize the clinical and angiographic consequences of this maneuver. We performed a retrospective review of a prospectively collected database of patients treated with the PED at a single academic center from 2011 to 2017 to find patients for whom the PED was extended across the origin of the ACA-A1. The patient demographic data, pretreatment angiographic imaging findings, sizing of the bilateral A1 and ipsilateral M1 segment of the middle cerebral artery (MCA-M1), and follow-up angiographic and clinical imaging findings were recorded. A total of 27 patients were included in the present study (8 men and 19 women; age, 52 ± 14.9 years). Follow-up angiography was conducted at a median of 9.2 months (interquartile range, 6; range, 5-84). The covered A1 segment was patent in 17 patients (63%). The covered ACA-A1/ipsilateral MCA-M1 ratio was 1.43 times greater for the patent ACA-A1 segments than those that were occluded (P= 0.0006). Similarly, the covered ACA-A1/contralateral ACA-A1 ratio was significantly larger statistically (1.64; P < 0.0001) for the patent ACA-A1 segments than that for those that were occluded. None of the patients developed clinical or radiographic signs of ACA stroke. The modified Rankin scale worsened for 1 patient during follow-up owing to a further decline of presenting vision loss. The PED can be used to treat aneurysms with deployment from the MCA-M1 to the ICA without resulting in ACA stroke. Ipsilateral A1 segment dominance might be predictive of continued blood flow into the ACA after deployment at this location.

Safety and Efficacy of the Pipeline Embolization Device Use in the Outside Circle of Willis Located Intracranial Aneurysms: A Single-Center Experience

Background: The use of Pipeline Embolization Device (PED) is approved by the US Food and Drug Administration (FDA) to treat aneurysms located between the petrous and superior hypophyseal segments of the internal carotid artery. The purpose of this study is to evaluate the feasibility and efficacy of treating aneurysms outside the FDA approved anatomical locations. Furthermore, we analyze the safety of our antiplatelet protocol. Methods: Data on all patients treated with PED at our center from March 2015 to December 2017 were reviewed. Only patients with aneurysms treated with PED as off label use were included. Procedural complications and long-term functional outcome measured by modified Rankin Scale (mRS) were recorded. Tirofiban maintenance infusion was administered intravenously after PED deployment. None of the patients had platelet function testing. Results: A total of 36 patients harboring 36 aneurysms were included in the study. Mean age was 58.2 years ±14.6. Nineteen were women (52.8%) and most aneurysms were unruptured (80.6%). There were no intraoperative complications. Five patients experienced postoperative complications – 4 ischemic strokes and one groin hematoma. None led to any significant disability at follow-up. Thirty-one patients (86.1%) achieved an mRS of 0–2 at follow-up. A Raymond-Roy classification of 1 was achieved in 78.9% of patients. Conclusion: The use of PED to treat aneurysms located outside the circle of Willis is feasible and effective. Our novel antiplatelet protocol did not require platelet function assay testing and did not lead to a higher rate of thrombo-embolic events compared to what has been previously reported.

Comparison of flow diversion with clipping and coiling for the treatment of paraclinoid aneurysms in 115 patients.

Paraclinoid aneurysms represent approximately 5% of intracranial aneurysms (Drake et al. [1968]). Visual impairment, which occurs in 16%-40% of patients, is among the most common presentations of these aneurysms (Day [1990], Lai and Morgan [2013], Sahlein et al. [2015], and Silva et al. [2017]). Flow-diverting stents, such as the Pipeline Embolization Device (PED), are increasingly used to treat these aneurysms, in part because of their theoretical reduction of mass effect (Fiorella et al. [2009]). Limited data on paraclinoid aneurysms treated with a PED exist, and few studies have compared outcomes of patients after PED placement with those of patients after clipping or coiling. The authors performed a retrospective analysis of 115 patients with an aneurysm of the cavernous to ophthalmic segments of the internal carotid artery treated with clipping, coiling, or PED deployment between January 2011 and March 2017. Postoperative complications were defined as new neurological deficit, aneurysm rupture, recanalization, or other any operative complication that required reintervention. A total of 125 paraclinoid aneurysms in 115 patients were treated, including 70 with PED placement, 23 with coiling, and 32 with clipping. Eighteen (14%) aneurysms were ruptured. The mean aneurysm size was 8.2 mm, and the mean follow-up duration was 18.4 months. Most aneurysms were discovered incidentally, but visual impairment, which occurred in 21 (18%) patients, was the most common presenting symptom. Among these patients, 15 (71%) experienced improvement in their visual symptoms after treatment, including 14 (93%) of these 15 patients who were treated with PED deployment. Complete angiographic occlusion was achieved in 89% of the patients. Complications were seen in 17 (15%) patients, including 10 (16%) after PED placement, 2 (9%) after coiling, and 5 (17%) after clipping. Patients with incomplete aneurysm occlusion had a higher rate of procedural complications than those with complete occlusion (p = 0.02). The rate of postoperative visual improvement was significantly higher among patients treated with PED deployment than in those treated with coiling (p = 0.01). The significant predictors of procedural complications were incomplete occlusion (p = 0.03), hypertension, (p = 0.04), and diabetes (p = 0.03). In a large series in which patient outcomes after treatment of paraclinoid aneurysms were compared, the authors found a high rate of aneurysm occlusion and a comparable rate of procedural complications among patients treated with PED placement compared with the rates among those who underwent clipping or coiling. For patients who presented with visual symptoms, those treated with PED placement had the highest rate of visual improvement. The results of this study suggest that the PED is an effective and safe modality for treating paraclinoid aneurysms, especially for patients who present with visual symptoms.

Immediate Flow Disruption as a Prognostic Factor After Flow Diverter Treatment: Long-Term Experience with the Pipeline Embolization Device.

To report long-term results after Pipeline Embolization Device (PED) implantation, characterize complex and standard aneurysms comprehensively, and introduce a modified flow disruption scale. We retrospectively reviewed a consecutive series of 40 patients harboring 59 aneurysms treated with 54 PEDs. Aneurysm complexity was assessed using our proposed classification. Immediate angiographic results were analyzed using previously published grading scales and our novel flow disruption scale. According to our new definition, 46 (78%) aneurysms were classified as complex. Most PED interventions were performed in the paraophthalmic and cavernous internal carotid artery segments. Excellent neurologic outcome (modified Rankin Scale 0 and 1) was observed in 94% of patients. Our data showed low permanent procedure-related mortality (0%) and morbidity (3%) rates. Long-term angiographic follow-up showed complete occlusion in 81% and near-total obliteration in a further 14%. Complete obliteration after deployment of a single PED was achieved in all standard aneurysms with 1-year follow-up. Our new scale was an independent predictor of aneurysm occlusion in a multivariable analysis. All aneurysms with a high flow disruption grade showed complete occlusion at follow-up regardless of PED number or aneurysm complexity. Treatment with the PED should be recognized as a primary management strategy for a highly selected cohort with predominantly complex intracranial aneurysms. We further show that a priori assessment of aneurysm complexity and our new postinterventional angiographic flow disruption scale predict occlusion probability and may help to determine the adequate number of per-aneurysm devices.

Mid-Term Outcome Following Pipeline Embolization of Unruptured Intracranial Aneurysms

Background: As an advanced generation of flow diverters (FD), pipeline embolization device (PED) is introduced for endovascular aneurysm occlusion. In the present study, we aimed to present the mid-term results after endovascular treatment of unruptured intracranial aneurysms using PED. Patients and Methods: A total of 20 patients with 20 intracranial wide neck aneurysms were treated with PED between July and October 2010. Patients were followed up 4 to 8 months after the procedure. Digital subtraction angiography (DSA) was carried out to assess stent integrity, displacement, and the presence of residual aneurysm. Results: Out of 20 participants, PED deployment was successful in 19; whereas, intervention failed in one patient due to technical factors in device deployment. No severe acute complications were observed. One patient died after three months as a result of subarachnoid hemorrhage (SAH). Out of the remaining patients, DSA showed complete occlusion of aneurysms in 14 individuals (77.8%), while in four patients (22.2%), residual aneurysm was noted. Stent migration was not observed in any patients. Intra-stent stenosis (25% - 50%) was visualized in only one patient (5.5%). Conclusion: This study showed promising mid-term results for the pipeline embolization device in the treatment of unruptured intracranial aneurysms. Larger studies with longer follow-up duration are warranted.