Immediate and follow-up results for 44 consecutive cases of small (<10 mm) internal carotid artery aneurysms treated with the pipeline embolization device

Management of Intracranial Aneurysms that Do Not Occlude on Initial Follow-up After Treatment With the Pipeline Embolization Device

BACKGROUND AND OBJECTIVES

The pipeline embolization device (PED) has become widely accepted as a safe and efficacious treatment for intracranial aneurysms with high rates of complete occlusion at initial follow-up. For aneurysms that are not completely occluded at initial follow-up, further treatment decision-making is varied. Furthermore, the risk of aneurysmal rupture in these incompletely occluded aneurysms after PED is not known. The objective of this study was to determine treatment decision-making that results in increased occlusion status at final follow-up and to evaluate risk of rupture in those aneurysms that do not go onto occlusion.

METHODS

This study is a retrospective review of prospective data for intracranial aneurysms treated with PED at two institutions from 2013 to 2019. Aneurysms with near-complete or incomplete occlusion at initial follow-up were included in the statistical analysis.

RESULTS

There were 606 total aneurysms treated at two academic institutions with PED with incomplete occlusion at initial follow-up in 134 aneurysms (22.1%). Of the 134 aneurysms that were nonoccluded at initial follow-up, 76 aneurysms (56.7%) went on to complete or near complete occlusion with final complete or near complete occlusion in 90.4% of all aneurysms treated. The time to final imaging follow-up was 28.2 months (13.8-44.3) Retreatment with a second flow diverter was used in 28 aneurysms (20.9%). No aneurysms that were incompletely occluded at initial follow-up had delayed rupture. Furthermore, older patient age was statistically significant for incomplete occlusion at initial follow-up ( P = .05).

CONCLUSION

Intracranial aneurysms treated with the PED that do not occlude at initial follow-up may go on to complete occlusion with continuous observation, alteration in antiplatelet regimens, or repeat treatment. Delayed aneurysmal rupture was not seen in patients with incomplete occlusion.

Endovascular Treatment in Precommunicating Segment Aneurysms of Posterior Cerebral Artery

BACKGROUND

Precommunicating (P1) segment aneurysms of the posterior cerebral artery are rare, with few studies reported to date. Herein, we address the clinical and radiologic outcomes of their endovascular treatment.

METHODS

For this study, we retrieved prospectively collected data on 35 consecutive patients with 37 P1 aneurysms, analyzing the clinical ramifications and morphologic outcomes of treatment. All subjects received endovascular interventions between January 2001 and October 2021.

RESULTS

There were 16 aneurysms (43.2%) of P1 segment sidewalls and 21 (56.8%) at P1/posterior communicating artery junctions. Five (13.5%) were fusiform, and 14 (37.8%) were ruptured. In 14 patients (40%), 16 aneurysms (43%) were associated with intracranial arterial occlusive disease of the anterior circulation. Selective coiling was undertaken in 34 aneurysms (91.9%), using single (n = 24) or double (n = 4) microcatheters, microcatheter protection (n = 2), or stents (n = 4); and trapping was done in 3 (8.1%). No procedure-related morbidity or mortality resulted. Excluding the trapped lesions, angiographic follow-up of 29 aneurysms obtained >6 months after embolization (mean, 12.4 month) revealed stable occlusion in 21 (72.4%), with some recanalization in the other 8 (minor: 3/29, 10.4%; major: 5/29, 17.2%).

CONCLUSIONS

Aneurysms of P1 segment (vs. other locations) are strongly associated with intracranial arterial occlusive disease of the anterior circulation and thus are likely flow related. Endovascular treatment of such lesions seems safe and efficacious, despite the array of technical strategies that their distinctive anatomic configurations impose.

Inflow Angle and Height-Width Ratio are Predictors of Incomplete Occlusion at One and Two Years After Flow Diverter Treatment for Small- and Medium-Sized Internal Carotid Artery Aneurysms

OBJECTIVE

We investigated the association between the inflow angle of aneurysms and their occlusion status at 1 and 2 years after flow diverter (FD) treatment.

METHODS

We retrospectively analyzed 42 consecutive patients from a single center with 43 untreated, unruptured internal carotid artery (ICA) proximal to communicating segment, saccular aneurysms sized <12 mm.

RESULTS

At 1 year posttreatment, the complete occlusion (CO) rate was 58.1%. On univariate analyses, the proportion of inflow angle >90° was significantly lower in the CO group than in the incomplete occlusion group (20.0% VS. 83.3%; P < 0.001). The CO incidence decreased with a height-width (H/W) ratio of <1.2 (P = 0.059). On multivariate analysis, an H/W ratio of <1.2 (odds ratio [OR], 0.076; P = 0.027) and an inflow angle of >90° (OR, 0.020; P = 0.0011) significantly influenced CO at 1 year post FD. At 2 years posttreatment, the CO rate was 76.3% (29/38 cases with available follow-up data). On univariate analyses, in the CO group compared to the incomplete occlusion group, the proportion of H/W ratio <1.2 was significantly lower (P = 0.005) and the proportion of inflow angle >90° was significantly lower (P = 0.021); aneurysm dome size tended to be larger (8.5 mm vs. 7.1 mm; P = 0.080). On multivariate analysis, an H/W ratio <1.2 (OR, 0.042; P = 0.015) and an inflow angle >90° (OR: 0.088; P = 0.031) significantly influenced CO at 2 years post FD.

CONCLUSIONS

The inflow angle of >90° and H/W ratio <1.2 may significantly influence the CO rate in small- or medium-sized internal carotid artery aneurysms 1 and 2 years post FD.

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.

Prospective study on embolization of intracranial aneurysms with the pipeline device (PREMIER study): 3-year results with the application of a flow diverter specific occlusion classification

BACKGROUND

The pipeline embolization device (PED; Medtronic) has presented as a safe and efficacious treatment for small- and medium-sized intracranial aneurysms. Independently adjudicated long-term results of the device in treating these lesions are still indeterminate. We present 3-year results, with additional application of a flow diverter specific occlusion scale.

METHODS

PREMIER (prospective study on embolization of intracranial aneurysms with pipeline embolization device) is a prospective, single-arm trial. Inclusion criteria were patients with unruptured wide-necked intracranial aneurysms ≤12 mm. Primary effectiveness (complete aneurysm occlusion) and safety (major neurologic event) endpoints were independently monitored and adjudicated.

RESULTS

As per the protocol, of 141 patients treated with a PED, 25 (17.7%) required angiographic follow-up after the first year due to incomplete aneurysm occlusion. According to the Core Radiology Laboratory review, three (12%) of these patients progressed to complete occlusion, with an overall rate of complete aneurysm occlusion at 3 years of 83.3% (115/138). Further angiographic evaluation using the modified Cekirge-Saatci classification demonstrated that complete occlusion, neck residual, or aneurysm size reduction occurred in 97.1%. The overall combined safety endpoint at 3 years was 2.8% (4/141), with only one non-debilitating major event occurring after the first year. There was one case of aneurysm recurrence but no cases of delayed rupture in this series.

CONCLUSIONS

The PED device presents as a safe and effective modality in treating small- and medium-sized intracranial aneurysms. The application of a flow diverter specific occlusion classification attested the long-term durability with higher rate of successful aneurysm occlusion and no documented aneurysm rupture.

TRIAL REGISTRATION

NCT02186561.

A comparison of antiplatelet therapy during the peri- and post-operative periods following flow-diverting stent insertion for unruptured intracranial aneurysms: A systematic review

BACKGROUND

Flow diverters (FDs) are neuroendovascular stents indicated for the management of unruptured intracranial aneurysms. Due to their composition, dual antiplatelet therapy (DAPT) is essential during the peri- and post-operative periods to prevent thromboembolic events. However, there is limited consensus within the scientific community regarding which antiplatelets to use and dosing following neuroendovascular treatment of aneurysms.

METHOD

A systematic search of four electronic databases was conducted during November 2020 that included studies published between January 2010 and November 2020. Eligibility for inclusion included primary research articles, published in the English language and use of flow-diverting intracranial stents. Studies were excluded if they utilised combined therapies (e.g. FD with stent-assisted coiling), animal studies, clinical trial protocols and study population of less than 10 subjects.

RESULTS

Eighteen studies were identified for inclusion with a total of 1312 patients with 1355 unruptured intracranial aneurysms treated with FDs. Of these, 13 studies primarily investigated the use of clopidogrel with aspirin with low rates of haemorrhagic and thromboembolic complications. A forest plot of nine of these studies showed average efficacy of 88% at 95% confidence interval (CI) (SD + 5%) with 63% heterogeneity.

CONCLUSIONS

The large proportion of studies investigating clopidogrel and aspirin antiplatelet therapy presents a challenge in comparing antiplatelet regimens. Although prasugrel and ticagrelor have been identified as suitable alternatives to clopidogrel, these were based on studies with small cohort sizes. Glycoprotein IIb/IIIa inhibitors may be efficacious as rescue therapy for intra-procedural thrombosis. Further research is required to determine which antiplatelet is most suitable.

Expanding Indications for Flow Diverters: Distal Aneurysms, Bifurcation Aneurysms, Small Aneurysms, Previously Coiled Aneurysms and Clipped Aneurysms, and Carotid Cavernous Fistulas

Flow diverter devices have gained wide acceptance for the treatment of unruptured intracranial aneurysms. Most studies are based on the treatment of large aneurysms harboring on the carotid syphon. However, during the last years the “off-label” use of these stents has widely grown up even if not supported by randomized studies. This review examines the relevant literature concerning “off-label” indications for flow diverter devices, such as for distal aneurysms, bifurcation aneurysms, small aneurysms, recurrent aneurysms, and direct carotid cavernous fistulas.

Giant aneurysm of the bilateral vertebrobasilar junction treated by pipeline and coils: A case report and literature review

Giant aneurysm of the posterior circulation is associated with a higher risk of rupture compared with that of the anterior circulation. Furthermore, surgical clipping and interventional embolization for giant aneurysm of the posterior circulation are more difficult and complex to perform. The present study reported on the case of a 26-year-old female who exhibited a giant spherical aneurysm of the vertebrobasilar junction (VBJ) with a maximum diameter of ~35 mm that caused cervical discomfort. In addition, the patient experienced symptoms including left-sided walking and hoarseness caused by the compression of the brainstem and the posterior cranial nerves. The risks associated with performing surgery in this area are high and the prognosis is mainly poor. The patient of the present study was treated using the Pipeline Flex device with coil embolization. As a giant aneurysm of the VBJ simultaneously affects the bilateral vertebral arteries (VAs) and basilar artery, it is a unique condition and the treatment strategy must be personalized. Based on an analysis of the hemodynamic influence on the aneurysm in the present case, the Pipeline was placed through the left VA, the coils were packed through the right VA, and finally, the right VA was proximally occluded. At 7 months after embolization, the patient's modified Rankin scale score was 1 point. Upon analysis of the hemodynamic influence on the aneurysm of the VBJ, the VA with the larger shear force on the wall of the aneurysm was selected for occlusion to simplify the treatment of the aneurysm and to maximize the probability to achieve recovery.

Reduced 2-year aneurysm retreatment and costs among patients treated with flow diversion versus non-flow diversion embolization: A Premier Healthcare Database retrospective cohort study

Introduction

The use of endovascular treatments, including Pipeline embolization devices (PEDs) and coiling approaches (non-PEDs), has played an increasingly important role in the treatment of intracranial aneurysms. Despite multiple studies evaluating PEDs, a real-world evaluation of follow-up outcomes and costs remains to be completed.

Methods

The Premier Healthcare Database (PHD), 2010–2017, was queried to identify patients with unruptured intracranial aneurysms treated endovascularly. Rates of readmission, retreatment, and cost at the same hospital were compared between patients who underwent PED and non-PED endovascular treatments of their aneurysms. One-to-three (PED–to–non-PED) propensity score (PS) matching was performed to adjust for potential case selection bias into the PED cohort, with covariates including age group, sex, Charlson Comorbidity Index (CCI) group, payor, region, and randomized hospital identifier.

Results

A total of 679 patients underwent PED placement and 8432 had non-PED treatments. Prior to PS matching, there were significant but minor differences in age (56.7±12.8 vs. 58.2±12.6 years, p = 0.004) and sex (male 16.6% vs. 24.4%, p<0.0001) for PED and non-PED, respectively, but no differences in CCI (p = 0.08), length of stay (p = 0.88), or rate of routine discharge (p = 0.21). All-cause readmission/emergency department reevaluation rates in the two cohorts were similar at 30, 90, and 180 days and 1 and 2 years. Our results identified a significantly lower retreatment rate for PEDs at all follow-up time points over a 2-year period (range: 0.9–8.1%) compared with non-PED treatments (range: 1.7–11.6%). These findings remained consistent after PS matching: all-cause readmission/reevaluation rates were significantly lower in patients treated with PED at 90 days, 180 days, 1 year, and 2 years (p<0.001). Although the initial treatment costs were higher for PED at time of treatment (p<0.001), cumulative follow-up emergency department visit and readmission costs (inclusive of patients with no readmission and/or no retreatment) were significantly lower for patients with initial PED relative to non-PED treatment at 2 years (p = 0.021).

Conclusions

These results suggest that PEDs may potentially reduce downstream retreatment rates and costs. Further work is required to improve identification of patient subgroups that could benefit from PED over non-PED treatments both initially and during follow-up.

Immediate Postoperative Angiographic Stagnation of Contrast Media and T2-Weighted Magnetic Resonance Imaging Features within Aneurysmal Sac Are Associated with Early Regression of Large or Giant Aneurysm After Flow Diversion Only

BACKGROUND

We hypothesized that the immediate postoperative imaging features would be associated with early regression of flow-diverted aneurysms. We compared the imaging features from digital subtraction angiography and spin echo T2-weighted magnetic resonance imaging between those with early total regression and partial regression.

METHODS

A total of 30 consecutive patients with large and giant aneurysms were treated with pipeline embolization devices and divided into 2 groups according to the follow-up angiographic findings at 3-6 months. Of the 30 patients, 20 had had total or near total regression and 10 had had partial regression of the aneurysmal sac. The baseline characteristics, percent area of stagnated iodine contrast agent on anteroposterior and lateral angiographic views just after installation of the pipeline device, and median, minimal, and 10-percentile signal intensity of the aneurysmal sac on T2-weighted spin echo images 1 day after the procedure were compared between the 2 groups.

RESULTS

A comparison of the demographic data between the 2 groups showed no significant differences. The volume of the treated aneurysmal sac also did not differ significantly (2559.28 ± 3021.45 mm³ vs. 2551.76 ± 6550.58 mm³; P = 0.455). The total or near total regression group had a larger percent area of iodine stagnation on the lateral angiographic view compared with the partial regression group (52.26% vs. 23.35%; P = 0.002). The median, minimal, and 10-percentile signal intensity of the volume of interest were higher in the total or near total regression group than in the partial regression group (1.29 vs. 0.93 [P = 0.025]; 0.07 vs. 0.00 [P = 0.042]; 0.57 vs. 0.24 [P = 0.005]).

CONCLUSIONS

The percent area of contrast media stagnation on lateral angiograms and the median, minimal, and 10th-percentile signal intensity of the volume of interest of treated aneurysmal sacs on T2-weighted images can be used to predict early regression of aneurysmal sacs.

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.

Multicenter Study of Pipeline Flex for Intracranial Aneurysms

BACKGROUND

The Pipeline Flex (PED Flex; Medtronic, Dublin, Ireland) was designed to facilitate deployment and navigation compared to its previous iteration to reduce the rate of technical events and complications.

OBJECTIVE

To assess the neurological morbidity and mortality rates of the PED Flex at 30 d.

METHODS

Information from 9 neurovascular centers was retrospectively obtained between July 2014 and March 2016. Data included patient/aneurysm characteristics, periprocedural events, clinical, and angiographic outcomes. Multivariate logistic regression was performed to determine predictors of unfavorable clinical outcome (modified Rankin Scale [mRS] > 2).

RESULTS

A total of 205 patients harboring 223 aneurysms were analyzed. The 30-d neurological morbidity and mortality rates were 1.9% (4/205) and 0.5% (1/205), respectively. The rate of intraprocedural events without neurological morbidity was 6.8% (14/205), consisting of intraprocedural ischemic events in 9 patients (4.5%) and hemorrhage in 5 (2.4%). Other technical events included difficulty capturing the delivery wire in 1 case (0.5%) and device migration after deployment in another case (0.5%). Favorable clinical outcome (mRS 0-2) was achieved in 186 patients (94.4%) at discharge and in 140 patients (94.5%) at 30 d. We did not find predictors of clinical outcomes on multivariate analysis.

CONCLUSION

The 30-d rates of neurological morbidity and mortality in this multicenter cohort using the PED Flex for the treatment of intracranial aneurysms were low, 1.9% (4/205) and 0.5% (1/205), respectively. In addition, technical events related to device deployment were also low, most likely due to the latest modifications in the delivery system.

Antiplatelet Therapy in Flow Diversion

Dual antiplatelet therapy is typically employed as a means to mitigate thromboembolic complications after deployment of flow diverters, most commonly consisting of aspirin with either clopidogrel, prasugrel, or ticagrelor. Recent studies have demonstrated at least similar efficacy for ticagrelor as compared to clopidogrel in the form of periprocedural complications and angiographic results. Though controversial, systematic reviews of platelet function assay usage have demonstrated greater rates of thrombotic complications in antiplatelet hyporesponders and greater rates of hemorrhagic complications in hyperresponders. Though in its infancy, the management of antiplatelet therapy for acutely ruptured aneurysms treated with flow diversion is not yet standardized, with approaches including intravenous glycoprotein IIb-IIIa inhibitors and subsequent antiplatelet loading vs antiplatelet loading, response assessment, and subsequent treatment.

Pipeline Flex Embolization Device (PED Flex) for the treatment of intracranial aneurysms: Periprocedural outcomes and first-year angiographic results

Background/aim

The Pipeline Flex Embolization Device (PED Flex) is a new updated version of the PED classic that incorporates a new delivery system to allow facilitation of stent deployment, resheathing, and removal of the capture coil. This study evaluated the PED Flex in terms of the technical aspects of the procedure and first-year follow-up results.

Materials and methods

This retrospective study involved prospectively collected data from May 2015 to August 2017. The primary endpoint was technical aspects of the procedure, and the secondary endpoint was first-year follow-up results.

Results

Forty-nine patients with 59 target intracranial aneurysms were enrolled. Patients’ mean age was 52 years (range 21−71 years), and 31 (63.0%) were female. All aneurysms except for three were unruptured. The mean aneurysm diameter was 8 mm. Forty-seven patients with 56 aneurysms were successfully treated. Due to advancement, repositioning, and migration problems, 8 (13.1%) stents were not deployed and discharged. The total aneurysm occlusion rate was 77.0%. The mortality rate was 4.3%.

Conclusion

Our experience shows that the applicability and safety of the renewed delivery system provided by PED Flex for improving device apposition and opening has been proven with one-year angiographic and clinical follow-up results.

Predictors of cerebral aneurysm persistence and occlusion after flow diversion: a single-institution series of 445 cases with angiographic follow-up

OBJECTIVE Flow diversion requires neointimal stent overgrowth to deliver aneurysm occlusion. The existing literature on aneurysm occlusion is limited by heterogeneous follow-up, variable antiplatelet regimens, noninvasive imaging modalities, and nonstandard occlusion assessment. Using a large, single-center cohort with low attrition and standardized antiplatelet tapering, the authors evaluated outcomes after flow diversion of anterior circulation aneurysms to identify predictors of occlusion and aneurysm persistence. METHODS Data from a prospective, IRB-approved database was analyzed for all patients with anterior circulation aneurysms treated by flow diversion with the Pipeline embolization device (PED) at the authors' institution. Follow-up consisted of catheter cerebral angiography at 6 and 12 months postembolization. Clopidogrel was discontinued at 6 months and aspirin was reduced to 81 mg daily at 12 months. Occlusion was graded as complete, trace filling, entry remnant, or aneurysm filling. Multivariate logistic regression was performed to identify predictors of aneurysm persistence. RESULTS Follow-up catheter angiography studies were available for 445 (91%) of 491 PED procedures performed for anterior circulation aneurysms between August 2011 and August 2016. Three hundred eighty-seven patients accounted for these 445 lesions with follow-up angiography. The population was 84% female; mean age was 56 years and mean aneurysm size was 6.6 mm. Aneurysms arose from the internal carotid artery (83%), anterior cerebral artery (13%), and middle cerebral artery (4%). Morphology was saccular in 90% of the lesions, and 18% of the aneurysms has been previously treated. Overall, complete occlusion was achieved in 82% of cases at a mean follow-up of 14 months. Complete occlusion was achieved in 72%, 78%, and 87% at 6, 12, and 24 months, respectively. At 12 months, adjunctive coiling predicted occlusion (OR 0.260, p = 0.036), while male sex (OR 2.923, p = 0.032), aneurysm size (OR 3.584, p = 0.011), and incorporation of a branch vessel (OR 2.206, p = 0.035) predicted persistence. Notable variables that did not predict aneurysm occlusion were prior treatments, vessel of origin, fusiform morphology, and number of devices used. CONCLUSIONS This is the largest single-institution study showing high rates of anterior circulation aneurysm occlusion after Pipeline embolization. Predictors of persistence after flow diversion included increasing aneurysm size and incorporated branch vessel, whereas adjunctive coiling predicted occlusion.

Initial Treatment for Unruptured Intracranial Aneurysm and Its Follow-up: A Cost Analysis of Pipeline Flow Diverters versus Coiling

Purpose

Intracranial aneurysms are relatively common epidemiological problems for which the surveillance, treatment, and follow-up are costly. Although multiple studies have evaluated the treatment cost of aneurysms, the follow-up costs are often not examined. In our study, we analyzed how follow-up costs after treatment affected the overall cost of different endovascular techniques for treating aneurysms.

Materials and methods

An institutional database was used to evaluate the upfront and follow-up costs incurred by patients who underwent elective coiling or placement of a pipeline embolization device (PED) for the treatment of unruptured intracranial aneurysms from July 2011 to December 2017.

Results

A total of 114 patients (coiling, n = 37; PED, n = 77 ) were included in the study. There was no significant difference among patients in mean age [61.3 (±12.8 years) vs. 57.0 (±14.5 years); probability value (p) = 0.2], sex (male: 32.4% vs. 22.1%; p = 0.2), American Society of Anesthesiologists (ASA) grade (p = 0.5), discharge disposition (p = 0.1), mean length of stay [3.1 days (±5.5) vs. 2.4 days (±2.6); p = 0.2) or follow-up period [22.7 months (±18.5) vs. 18.6 months (±14.9); p = 0.2). There were no differences in costs during admission (p = 0.5) or in follow-up (p = 0.3) between coiling and PED treatments. Initial costs were predominantly related to supplies/implants (56.1% vs. 63.7%) for both treatments. Follow-up costs mostly comprised facility costs (68.2% vs. 67.5%), and there were no differences in costs of subgroups such as supplies/implants (10.5% vs. 9.4%), imaging (17.0% vs. 17.8%), or facilties between coiling and PED.

Conclusion

These results suggest that the upfront and follow-up costs are mostly similar for the treatment of intracranial aneurysms irrespective of whether the providers used coiling or PED endovascular techniques. Hence, we conclude that follow-up costs should not be a deciding factor when considering these treatments.

Prospective study on embolization of intracranial aneurysms with the pipeline device: the PREMIER study 1 year results

Background

Preliminary clinical studies on the safety and efficacy of the pipeline embolization device (PED) for the treatment of small/medium aneurysms have demonstrated high occlusion rates with low complications.

Objective

To evaluate the safety and effectiveness of the PED for treatment of wide necked small and medium intracranial aneurysms.

Methods

PREMIER is a prospective, multicenter, single arm trial. Patients were treated with the PED for unruptured wide necked aneurysms, measuring ≤12 mm along the internal carotid artery or vertebral artery, between July 2014 and November 2015. At 1 year post-procedure, the primary effectiveness endpoint was complete occlusion (Raymond grade 1) without major parent vessel stenosis (≤50%) or retreatment, and the primary safety endpoint was major stroke in the territory supplied by the treated artery or neurologic death.

Results

A total of 141 patients were treated with PEDs (mean age 54.6±11.3 years, 87.9% (124/141) women). Mean aneurysm size was 5.0±1.92 mm, and 84.4% (119/141) measured <7 mm. PED placement was successful in 99.3% (140/141) of patients. Mean number of PEDs implanted per patient was 1.1±0.26; a single PED was used in 92.9% (131/141) of patients. At 1 year, 97.9% (138/141) of patients underwent follow-up angiography with 76.8% (106/138) of patients having met the study’s primary effectiveness endpoint. The combined major morbidity and mortality rate was 2.1% (3/140).

Conclusions

Treatment of wide necked small/medium aneurysms with the PED results in high rates of complete occlusion without significant parent vessel stenosis and low rates of permanent neurologic complications.

Trial registration

NCT02186561.

Outcome of intracranial flow diversion according to the antiplatelet regimen used: a systematic review and meta-analysis

Background

Thromboembolic complications are not uncommon in patients undergoing neurointerventional procedures. The use of flow diverting stents is associated with higher risks of these complications despite current dual antiplatelet regimens.

Objective

To explore contemporary evidence on the safety of emerging dual antiplatelet regimens in flow diverting stenting procedures.

Methods

We performed a systematic review and meta-analysis to identify relevant articles in electronic databases, and relevant references. Studies reporting the complications and mortality of flow diverting stenting procedures using acetyl salicylic acid (ASA) + ticagrelor or ASA + prasugrel compared with ASA + clopidogrel were included.

Results

Of 452 potentially relevant studies, we identified 49 studies (2526 patients) which reported the safety of ticagrelor or prasugrel for pooled analysis, and five studies (1005 patients) for meta-analysis. The pooled overall mortality in all studies was 2.14%, ischemic complications 6.89%, and hemorrhagic complications 3.68%. The use of ticagrelor or prasugrel was associated with a lower risk of mortality compared with clopidogrel (RR=4.57, 95% CI 1.23 to 16.99; p=0.02). Considering ischemic events, ASA + clopidogrel was as safe as ASA + prasugrel (RR=0.55, 95% CI 0.11 to 2.74; p=0.47) and ASA + ticagrelor (RR=0.74, 95% CI 0.32 to 1.74; p=0.49). ASA +ticagrelor was not associated with a higher risk of hemorrhagic complications (RR=0.92, 95% CI 0.27 to 3.16; p=0.89).

Conclusions

Evidence suggests that dual antiplatelet regimens including ticagrelor or prasugrel are safe for patients undergoing flow diversion procedures. Regimens using ticagrelor were associated with better survival than those using clopidogrel in the included studies.

Pipeline Embolization of Vertebrobasilar Aneurysms—A Multicenter Case Series

BACKGROUND

The Pipeline Embolization Device (PED) has been increasingly used for the treatment of posterior circulation aneurysms. The purpose of the present study was to examine the clinical and angiographic outcomes of patients with vertebrobasilar aneurysms treated with the PED.

METHODS

We performed a retrospective review of vertebrobasilar aneurysms treated with the PED at 4 high-volume neurovascular centers. Patient, aneurysm, and procedural data were collected, including perioperative and delayed complications. Aneurysm occlusion on follow-up imaging studies was defined as complete (100%), near-complete (>90%), or incomplete (<90%) occlusion.

RESULTS

The cohort included 35 patients with 37 vertebrobasilar aneurysms who underwent 36 treatment sessions. Of the 35 patients, 10 were men (29%), and the mean patient age was 54.1 years (range, 32-75). Eight patients (23%) underwent urgent treatment because of a ruptured aneurysm (n = 6), brainstem perforator stroke (n = 1), or post-traumatic pseudoaneurysm (n = 1). Of the 37 aneurysms, 22 arose from the vertebral artery (59%) and 15 from the basilar artery (41%). Also, 19 were saccular aneurysms (51%), with a mean size of 7.7 mm (range, 1.7-38.0); 17 were fusiform aneurysms (46%), with a mean size of 11.0 mm (range, 4.3-34); and 1 was a 2.9-mm blister aneurysm. The overall procedural complication rate was 14% (5 of 36), including 3 neurologically symptomatic complications. At a mean follow-up period of 14 months (range, 3-59), 24 of 34 aneurysms (71%) were completely occluded and 29 of 34 (85%) were completely or near-completely occluded.

CONCLUSION

Our results show that Pipeline embolization of vertebrobasilar aneurysms is associated with acceptable occlusion and complication rates.

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.

Declining complication rates with flow diversion of anterior circulation aneurysms after introduction of the Pipeline Flex: analysis of a single-institution series of 568 cases

OBJECTIVE

The second-generation Pipeline embolization device (PED), Flex, has several design upgrades, including improved opening and the ability to be resheathed, in comparison with the original device (PED classic). The authors hypothesized that Flex is associated with a lower rate of major complications.

METHODS

A prospective, IRB-approved, single-institution database was analyzed for all patients with anterior circulation aneurysms treated by flow diversion. The PED classic was used from August 2011 to January 2015, and the Pipeline Flex has been used since February 2015.

RESULTS

A total of 568 PED procedures (252 classic and 316 Flex) were performed for anterior circulation aneurysms. The average aneurysm size was 6.8 mm. Patients undergoing treatment with the Flex device had smaller aneurysms (p = 0.006) and were more likely to have undergone previous treatments (p = 0.001). Most aneurysms originated along the internal carotid artery (89% classic and 75% Flex) but there were more anterior cerebral artery (18%) and middle cerebral artery (7%) deployments with Flex (p = 0.001). Procedural success was achieved in 96% of classic and 98% of Flex cases (p = 0.078). Major morbidity or death occurred in 3.5% of cases overall: 5.6% of classic cases, and 1.9% of Flex cases (p = 0.019). On multivariate logistic regression, predictors of major complications were in situ thrombosis (OR 4.3, p = 0.006), classic as opposed to Flex device (OR 3.7, p = 0.008), and device deployment in the anterior cerebral artery or middle cerebral artery as opposed to the internal carotid artery (OR 3.5, p = 0.034).

CONCLUSIONS

Flow diversion of anterior circulation cerebral aneurysms is associated with an overall low rate of major complications. The complication rate is significantly lower since the introduction of the second-generation PED (Flex).

Antiplatelet therapy and the risk of ischemic and hemorrhagic complications associated with Pipeline embolization of cerebral aneurysms: a systematic review and pooled analysis

BACKGROUND

Pipeline embolization devices (PEDs) are increasingly used in the treatment of cerebral aneurysms. Yet, major ischemic or hemorrhagic complications after PED treatment associated with antiplatelet regimens are not well-established.

OBJECTIVE

To investigate the risk of ischemic and hemorrhagic complications associated with common antiplatelet regimens following PED treatment, and to examine whether platelet function testing (PFT) is associated with a lower risk of these complications.

METHODS

We searched Medline, Embase, and Cochrane from 2009 to 2017. Twenty-nine studies were included that had reported a uniform antiplatelet regimen protocol and had provided data on major ischemic and hemorrhagic complications following PED treatment. Random-effect meta-analysis was used to pool overall ischemic and hemorrhagic event rates across studies. The rate of these complications with respect to the antithrombotic regimen and PFT was assessed by χ² proportional tests.

RESULTS

Overall, 2002 patients (age 55.9 years, 76% female) were included. A low-dose acetylsalicylic acid (ASA) regimen before and after PED treatment was associated with a higher rate of late ischemic complications than with high-dose ASA therapy (2.62 (95% CI 1.46 to 4.69) and 2.56 (1.41 to 4.64), respectively). Duration of post-procedure clopidogrel therapy <6 months was associated with greater rates of ischemic complications (1.56, 95% CI 1.11 to 2.20) than a clopidogrel regimen of ≥6 months. Performing PFT before PED treatment was not associated with the risk of ischemic complications (1.27, 95% CI 0.77 to 2.10).

CONCLUSION

High-dose ASA therapy and clopidogrel treatment for at least 6 months were associated with a reduced incidence of ischemic events, without affecting the risk of hemorrhagic events.

Abciximab (ReoPro) Dosing Strategy for the Management of Acute Intraprocedural Thromboembolic Complications during Pipeline Flow Diversion Treatment of Intracranial Aneurysms

Background

Flow diversion with the Pipeline embolization device (PED) is an effective neuro-endovascular method and increasingly accepted for the treatment of cerebral aneurysms. Acute in situ thrombosis is a known complication of PED procedures. There is limited experience in the flow diversion literature on the use of abciximab (ReoPro) for the management of acute thrombus formation in PED cases.

Methods

Data were collected retrospectively on patients who received intra-arterial (IA) ReoPro with or without subsequent intravenous (IV) infusion during PED flow diversion treatment of intracranial aneurysms.

Results

A total of 30 cases in patients with a mean age of 56.7 years (range 36-84) and a mean aneurysm size of 8.6 mm (range 2-25) were identified to have intraprocedural thromboembolic complications during PED treatment. IA ReoPro was administered in all cases, with 20 cases receiving increments of 5-mg boluses and 10 cases receiving a 0.125 mg/kg IA bolus (half cardiac dosing). Complete or partial recanalization was achieved in 100% of the cases. IV ReoPro infusion at 0.125 μg/kg/min for 12 h was administered postprocedurally in 22 cases with a residual thrombus. Postprocedurally, 18 patients were transitioned from clopidogrel (Plavix) to prasugrel (Effient). The majority of the cases (23/30; 77%) were discharged home. Periprocedural intracranial hemorrhage was noted in 2 cases (7%) and radiographic infarct was noted in 4 cases (13%), with an overall mortality of 0% at the time of initial discharge. Clinical follow-up was available for 28/30 patients. The average duration of follow-up was 11.7 months, at which time 23/28 (82%) of the patients had a modified Rankin Scale score of 0.

Conclusions

IA ReoPro administration is an effective and safe rescue strategy for the management of acute intraprocedural thromboembolic complications during PED treatment. Using a dosing strategy of either 5-mg increments or a 0.125 mg/kg IA bolus (half cardiac dosing) can provide high rates of recanalization with low rates of hemorrhagic complications and long-term morbidity.

Treatment of Small and Tiny Aneurysms Before and After Flow Diversion Era: A Single Center Experience of 409 Aneurysms

OBJECTIVE

To explore whether we should use the Pipeline embolization device (PED) as the primary treatment modality for small and tiny aneurysms at anterior circulation.

METHODS

This retrospective study included 409 cases of small and tiny aneurysms, including aneurysms treated by the PED (n = 77), coiling (n = 51), and stent-assisted coiling (SAC) (n = 281). We also made a comparison regarding the safety and efficacy among these treatment modalities.

RESULTS

A total of 55 patients with 77 small aneurysms were treated with PEDs. Technical success was achieved in 98.4% of procedures. The complete occlusion rate was 75.9% (44/58). Both the morbidity and mortality rates were 1.8%. Comparing the 3 treatment modalities, the technical event rate tended to be the highest in the PED group (4.8% vs. 2.0% and 1.1%; PED vs. Coil vs. SAC; P = 0.100), and the use of a PED neither significantly shortened the procedure duration (127.2 ± 62.8 vs. 115 ± 37.1 and 112.8 ± 40.6 minutes, P = 0.322) nor lowered the complication rate (11.1% vs. 9.8% and 6.1%; P = 0.281). SAC had the highest occlusion rate (75.9% vs. 75.8% and 94.0%; P < 0.001) and lowest morbidity rate (0.8% vs. 4.2% and 1.8%; SAC vs. Coil vs. PED; P = 0.099). Ipsilateral multiple aneurysms were more frequently seen in the PED group (33.8% vs. 3.9% and 3.2%; P < 0.001). Procedure duration tended to be lower in the PED group versus the SAC group (122.7 ± 57.4 vs. 157.5 ± 22.2 minutes; P = 0.060). For these aneurysms, the PED group had the highest occlusion rate (80.0% vs. 50.0% and 66.7%; P = 0.516).

CONCLUSIONS

The PED is an alternative treatment for small and tiny aneurysms. However, SAC remains the safest and most efficient treatment modality. The PED should be reserved for ipsilateral multiple aneurysms.

47 Consecutive Cases of Pipeline Flex Flow Diversion Utilizing a Novel Large-Bore Intracranial Intermediate Catheter: Nuances and Institutional Experience with the Syphontrak

Background

The increasing complexity of modern neurointerventions has necessitated a shift in intracranial access techniques towards more robust distal support platforms. Here we present our experience with the Syphontrak Support Catheter (Codman Neuro, Raynham, MA, USA) in the triaxial platform for the implantation of the second-generation Pipeline Flex embolization device (PED Flex; Medtronic Neurovascular, Irvine, CA, USA).

Methods

We retrospectively identified patients who underwent PED Flex treatment utilizing the Syphontrak at a single institution. The procedural data collected included parent artery tortuosity, patient demographics, aneurysm characteristics, other equipment utilized, and catheter-related complications.

Results

A total of 47 consecutive aneurysm flow diversions were successfully performed using the Syphontrak. The patients' age ranged from 25 to 80 years (mean 57.3 ± 11.6) and 85% were women. The average aneurysm size was 4.8 ± 2.7 mm (range 2-14). All cases were in the anterior circulation, with 6 (12%) aneurysms located beyond the internal carotid artery termination. Significant cervical carotid tortuosity was present in 23% (11/47) of the cases and moderate-to-severe cavernous tortuosity (cavernous grade ≥2) in 51% (24/47) of the cases. The mean fluoroscopy time was 36.6 ± 14.8 min. In 12/47 cases (26%), vasospasm prophylaxis with intra-arterial verapamil infusion was performed. The Syphontrak was tracked to the intended distal position in all cases, with a 100% technical success of PED Flex implantation. Forty-six (98%) of the 47 patients were discharged home after an average length of stay of 1.38 days. No iatrogenic catheter-related vessel injury occurred. Transient, minor neurological morbidity occurred in 3 cases (6%) and 1 patient had a minor ischemic event (NIHSS score < 4) in the periprocedural period.

Conclusion

The Syphontrak is a new large-bore, multi-durometer intermediate catheter (IC) designed for use in modern neurointerventional procedures. We have shown its utility in 47 successful cases of PED Flex flow diversion of a wide range of complexity. The IC provides robust and atraumatic distal intracranial access while also providing an enhanced image quality with its large 0.060″ inner diameter.

Pipeline for uncoilable or failed aneurysms: 3-year follow-up results

OBJECTIVE

The long-term effectiveness of endovascular treatment of large and giant wide-neck aneurysms using traditional endovascular techniques has been disappointing, with high recanalization and re-treatment rates. Flow diversion with the Pipeline Embolization Device (PED) has been recently used as a stand-alone therapy for complex aneurysms, showing significant improvement in effectiveness while demonstrating a similar safety profile to stent-supported coil treatment. However, relatively little is known about its long-term safety and effectiveness. Here the authors report on the 3-year safety and effectiveness of flow diversion with the PED in a prospective cohort of patients with large and giant internal carotid artery aneurysms enrolled in the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial.

METHODS

The PUFS trial is a prospective study of 107 patients with 109 aneurysms treated with the PED. Primary effectiveness and safety end points were demonstrated based on independently monitored 180-day clinical and angiographic data. Patients were enrolled in a long-term follow-up protocol including 1-, 3-, and 5-year clinical and imaging follow-up. In this paper, the authors report the midstudy (3-year) effectiveness and safety data.

RESULTS

At 3 years posttreatment, 74 subjects with 76 aneurysms underwent catheter angiography as required per protocol. Overall, complete angiographic aneurysm occlusion was observed in 71 of these 76 aneurysms (93.4% cure rate). Five aneurysms were re-treated, using either coils or additional PEDs, for failure to occlude, and 3 of these 5 were cured by the 3-year follow-up. Angiographic cure with one or two treatments of Pipeline embolization alone was therefore achieved in 92.1%. No recanalization of a previously completely occluded aneurysm was noted on the 3-year angiograms. There were 3 (2.6%) delayed device- or aneurysm-related serious adverse events, none of which led to permanent neurological sequelae. No major or minor late-onset hemorrhagic or ischemic cerebrovascular events or neurological deaths were observed in the 6-month through 3-year posttreatment period. Among 103 surviving patients, 85 underwent functional outcome assessment in which modified Rankin Scale scores of 0–1 were demonstrated in 80 subjects.

CONCLUSIONS

Pipeline embolization is safe and effective in the treatment of complex large and giant aneurysms of the intracranial internal carotid artery. Unlike more traditional endovascular treatments, flow diversion results in progressive vascular remodeling that leads to complete aneurysm obliteration over longer-term follow-up without delayed aneurysm recanalization and/or growth.

Clinical trial registration no.: NCT00777088 (clinicaltrials.gov)

Comparison of Stent-Assisted Coil Embolization and the Pipeline Embolization Device for Endovascular Treatment of Ophthalmic Segment Aneurysms: A Multicenter Cohort Study

BACKGROUND

Stent-assisted coil embolization and flow diversion with the Pipeline embolization device (PED) are both effective endovascular treatment options for ophthalmic segment aneurysms (OSAs) of the internal carotid artery. Here we present a large comparative cohort study.

METHODS

A multicenter, retrospective cohort comparison study of consecutively treated OSAs was conducted at 2 academic institutions in the United States comparing stent-coiling (between 2007 and 2015) and PED (between 2011 and 2016).

RESULTS

A total of 62 of OSAs were treated with stent-coiling and 106 were treated with the PED. The stent-coiling-treated aneurysms were larger, although the maximum diameter was not significantly different between the 2 groups (P = 0.05). The median duration of follow-up was 22.5 months for the stent-coiling group and 8.7 months for the PED group (P = 0.0002). Complete occlusion at last follow-up was achieved in 75.9% of aneurysms in the stent-coiling group and in 81.1% of aneurysms in the PED group (P = 0.516). The retreatment rate was higher with stent-coiling, but the difference did not reach statistical significance (P = 0.062). A good functional outcome was achieved in 96.6% of patients in the stent-coiling group and in 94.7% of those in the PED group (P = 0.707). The rate of neurologic complications was 4.8% in the stent-coiling group and 9.4% in the PED group (P = 0.376).

CONCLUSION

Stent-coiling and the PED were equally effective for treating OSAs. There were no significant differences in terms of procedural complications, angiographic, functional, and visual outcomes. PED may be more favorable for multiple adjacent OSAs.

Expanding the use of flow diverters beyond their initial indication: treatment of small unruptured aneurysms

Background

Experience with the endovascular treatment of unruptured small intracranial aneurysms by flow diverter devices is still limited.

Objective

To assess the safety and efficacy of the SILK flow diverter (SFD) in the treatment of small unruptured cerebral aneurysms (<10 mm).

Methods

We performed a retrospective review of a prospectively maintained database of patients treated with a SFD between July 2008 and December 2013 at 4 institutions in Spain to identify all patients with small unruptured aneurysms (<10 mm). Data for patient demographics, aneurysm characteristics, and technical procedures were analyzed. Angiographic and clinical findings were recorded during the procedure and at 6- and 12-month follow-ups.

Results

A total of 109 small aneurysms were treated with a SFD in 104 patients (78 women; 26 men; mean, median, and range of age: 55.2, 57.1, and 19–80 years, respectively). A total of 60 patients were asymptomatic (57.7%). All except 7 aneurysms (6.4%) arose from the anterior circulation. The mean size of the aneurysms was 4.7±1.9 mm. At 6 months, the neuromorbidity and neuromortality rates were 2.9% and 0.9%, respectively. Imaging at the 12-month follow-up showed complete occlusion, neck remnants, and residual aneurysm in 88.5% (69/78), 7.7% (6/78), and 3.3% (3/78) of cases, respectively. No delayed hemorrhage occurred.

Conclusions

The findings suggest that the indications for SFD can be safely extended to small intracranial aneurysms.

Off-label uses of the Pipeline embolization device: a review of the literature

The Pipeline embolization device (PED) is the most widely used flow diverter in endovascular neurosurgery. In 2011, the device received FDA approval for the treatment of large and giant aneurysms in the internal carotid artery extending from the petrous to the superior hypophyseal segments. However, as popularity of the device grew and neurosurgeons gained more experience, its use has extended to several other indications. Some of these off-label uses include previously treated aneurysms, acutely ruptured aneurysms, small aneurysms, distal circulation aneurysms, posterior circulation aneurysms, fusiform aneurysms, dissecting aneurysms, pseudoaneurysms, and even carotid-cavernous fistulas. The authors present a literature review of the safety and efficacy of the PED in these off-label uses.

Factors Affecting the Obliteration Rate of Intracranial Aneurysms Treated with a Single Pipeline Embolization Device

OBJECTIVE

To evaluate the clinical and angiographic outcomes of intracranial aneurysm treatment using a single Pipeline embolization device (PED), and to evaluate the factors affecting aneurysm obliteration rate.

METHODS

The demographic characteristics and anatomic features of 58 aneurysms in 47 patients treated with a single PED were reviewed retrospectively. All aneurysms treated with a PED at a single center and with follow-up angiograms for at least 6 months were included in this study.

RESULTS

The overall rate of complete and near-complete occlusion was 84% (49 of 58) after a mean follow-up period of 18.3 months. The rate of complete aneurysm obliteration was lower in aneurysms with an arterial branch arising from the aneurysm neck compared with aneurysms without an arterial branch (13% [1 of 8] vs. 68% [34 of 50]; P = 0.0075). The overall rate of complete and near-complete aneurysm occlusion was 90% (45 of 50) in aneurysms without an arterial branch arising from its neck. There were no statistically significant associations between obliteration rate and aneurysm neck width, size, or type, or history of previous coil embolization.

CONCLUSIONS

Our data suggest that a single PED is sufficient to induce complete or near-complete obliteration of most aneurysms. The presence of a branching artery arising from the aneurysm neck is highly predictive of incomplete occlusion after treatment with a single PED.

Matched Comparison of Flow Diversion and Coiling in Small, Noncomplex Intracranial Aneurysms

BACKGROUND: Flow diversion is typically reserved for large, giant, or morphologically complex aneurysms. Coiling remains a first-line treatment for small, morphologically simple aneurysms.

OBJECTIVE: To compare coiling and flow diversion in small, uncomplicated intracranial aneurysms (typically amenable to coiling).

METHODS: Forty patients treated with the pipeline embolization device (PED) for small (&lt;10 mm), morphologically simple aneurysms that would have also been amenable to coiling were identified. These patients were matched in a 1:1 fashion with 40 patients with comparable aneurysms treated with coiling. Matching was based on age, gender, aneurysm size, and aneurysm morphology.

RESULTS: The 2 groups were comparable with regard to baseline characteristics including age, gender, and aneurysm size. The complication rate did not differ between the 2 groups (2.5% with coiling vs 5% with PED; P = .6). Multivariate analysis did not identify any predictor of complications. Complete occlusion (100%) at follow-up was significantly higher in patients treated with PED (70%) than coiling (47.5%, P = .04). In multivariate analysis, treatment with PED predicted aneurysm obliteration (P = .04). A significantly higher proportion of coiled patients (32.5%) required retreatment compared with flow diversion (5%, P = .003). In multivariate analysis, coiling predicted retreatment (P = .006). All patients achieved a favorable outcome (modified Rankin Scale: 0-2) regardless of group.

CONCLUSION: This matched analysis suggests that flow diversion provides higher occlusion rates, lower retreatment rates, and no additional morbidity compared with coiling in small, simple aneurysms amenable to both techniques. These results suggest a potential benefit for flow diversion over coiling even in small, uncomplicated aneurysms.

Rescue Treatment with Pipeline Embolization for Postsurgical Clipping Recurrences of Anterior Communicating Artery Region Aneurysms

Background

Postsurgical clipping aneurysm recurrences or residuals can be difficult to manage with either traditional open microsurgical approaches or endosaccular coiling. Endoluminal parent vessel reconstruction with flow diversion may be an ideal method for treating these recurrences by avoiding reoperative surgery or intraprocedural aneurysm rupture with aneurysm access.

Method

We retrospectively reviewed a single-center aneurysm database identifying all anterior communicating artery (ACom) region aneurysms with recurrences after microsurgical clipping. Cases subsequently treated with Pipeline embolization device (PED) were identified for analysis.

Results

Nine PED neurointerventions were performed for the treatment of 6 ACom region recurrent aneurysms after surgical clipping (ACom, n = 4 and A1-A2 junction, n = 2). Of the 6 aneurysms treated, 4 were previously ruptured. Mean patient age was 59.5 ± 6.9 years (range 50-67 years). Mean aneurysm size was 5.1 ± 2.2 mm (range 3-9 mm). Mean fluoroscopy time was 44.1 ± 12.4 min. A single PED, deployed from ipsilateral A2 to ipsilateral A1, was used in 6 cases. No instances of periprocedural complications were encountered. Angiographic follow-up was available in all aneurysms; 5 of these 6 (83%) demonstrated complete aneurysm occlusion.

Conclusion

Flow diversion with PED can be a safe and efficacious treatment approach for recurrent ACom region aneurysms after surgical clipping.

Endovascular flow diversion for treatment of anterior communicating artery region cerebral aneurysms: a single-center cohort of 50 cases

BACKGROUND

Flow diversion represents a novel but definitive treatment for recurrent and difficult-to-coil aneurysms of the anterior communicating artery (ACoA) region, of which reports are limited.

OBJECTIVE

To determine the effectiveness of the Pipeline embolization device (PED) in treating aneurysms in the ACoA region.

METHODS

We retrospectively reviewed an IRB-approved database of patients with an aneurysm at a single institution for patients with ACoA or A1-A2 aneurysms treated with PED. Data analyzed included demographics, aneurysm characteristics, procedural details, follow-up results, and outcomes.

RESULTS

A total of 50 procedures were performed on 41 patients, including seven patients who underwent bilateral 'H-pipe' PED placement. The average age was 56 years and 46% of the patients were female. The average aneurysm size was 4.5 mm, and two large (>10 mm) aneurysms were treated. The vessel of origin was either the ACoA (26 aneurysms, 63%) or the A1-A2 junction (15 aneurysms, 37%). Eighteen patients (44%) had prior subarachnoid hemorrhage and 20 had previously been treated either with clipping (6 aneurysms, 15%) or coiling (14 aneurysms, 34%). Procedural success was achieved in 48/50 cases (96%) and two cases were aborted. Coils were deployed adjunctively in two cases (4%). Procedural outcomes included no deaths, one major ischemic stroke (2%), and two patients with intracranial hemorrhage (4%). Complete aneurysm occlusion was achieved in 81% of patients at 6 months and 85% of patients at last follow-up digital subtraction angiography.

CONCLUSIONS

The PED can be used safely and effectively in the treatment of aneurysms of the ACoA region. This represents a good alternative treatment option to microsurgical clipping and endovascular coiling.

Ophthalmic artery occlusion after Pipeline Embolization Device placement with reconstitution of flow via an endoleak: a report of two cases

The Pipeline Embolization Device (PED) is a flow diverting stent used in the treatment of a wide variety of intracranial aneurysms. The device differs from traditional stents used in stent-assisted coil embolization in that it has a tighter lattice structure with smaller cell sizes designed specifically to disrupt blood flow into aneurysms rather than only to retain coils within aneurysms. While the PED has been shown to be safe and effective, it has a unique risk profile that includes side branch and perforator vessel occlusion. Side branch occlusion in particular has been noted in several articles to occur at a relatively high rate with coverage of the ophthalmic artery origin by the PED. In this series, we present two cases of ophthalmic artery occlusion after PED placement with reconstitution of flow via an endoleak.

Pipeline Embolization Device for Small Intracranial Aneurysms: Evaluation of Safety and Efficacy in a Multicenter Cohort

BACKGROUND: To date, the use of the flow-diverting Pipeline Embolization Device (PED) for small intracranial aneurysms (≤ 7 mm) has been reported only in single-center series.

OBJECTIVE: To evaluate the safety and efficacy of the PED in a multicenter cohort.

METHODS: Five major academic institutions in the United States provided data on patient demographics, aneurysm features, and treatment characteristics of consecutive patients with aneurysms ≤ 7 mm treated with a PED between 2009 and 2015. Radiographic outcome was assessed with digital subtraction angiography. Clinical outcome was measured with the modified Rankin Scale.

RESULTS: The cumulative number of aneurysms ≤ 7 mm treated with PED at the 5 institutions was 149 in 117 patients (age, 54 years [range, 29-87 years]; male to female, 1-5.9). Aneurysms were most commonly located in the paraophthalmic segment (67.1%) of the internal carotid artery. Radiographic outcome at last follow-up was available for 123 aneurysms (82.6%), with a complete occlusion rate of 87%. Thromboembolic and symptomatic procedural complications occurred in 8.7% and 6% of the aneurysms treated, respectively. There was 1 mortality (0.9%) unrelated to the PED procedure. Multivariable logistic regression identified size &lt; 4 mm, balloon angioplasty to open the device, and simultaneous treatment of multiple aneurysms as predictors of procedural complications. Good clinical outcome was achieved in 96% of electively treated patients.

CONCLUSION: In the largest series on PED for small aneurysms to date, data suggest that treatment with the flow-diverting PED is safe and efficacious, with complication rates comparable to those for traditional endovascular techniques.

Safety and efficiency of flow diverters for treating small intracranial aneurysms: A systematic review and meta-analysis

Background

We evaluated the safety and efficiency of flow diverters (FDs) in treating small intracranial aneurysms (IAs).

Materials and Methods

We reviewed the literature published in PubMed and EMBASE. R for Project software was used to calculate the complete aneurysm occlusion rates, procedure-related neurologic mortality, procedure-related neurologic morbidity and procedure-related permanent morbidity.

Results

Ten observational studies were included in this analysis. The complete aneurysm occlusion rate was 84.23% (80.34%–87.76%), the procedure-related neurologic mortality was 0.87% (0.29%–1.74%), the procedure-related neurologic morbidity rate was 5.22% (3.62%–7.1%), the intracerebral haemorrhage rate was 1.42% (0.64%–2.49%), the ischemic rate was 2.35% (1.31%–3.68%), the subarachnoid haemorrhage rate was 0.03% (0%–0.32%) and the procedure-related permanent morbidity was 2.41% (0.81%–4.83%).

Conclusions

Treatment of small IAs with FDs may be correlated with high complete occlusion rates and low complication rates. Future long-term follow-up randomized trials will determine the optimal treatment for small IAs.

Cerebral aneurysm treatment: modern neurovascular techniques

Endovascular treatment of cerebral aneurysm continues to evolve with the development of new technologies. This review provides an overview of the recent major innovations in the neurointerventional space in recent years.

Delayed Collapse of a Pipeline Embolization Device

BACKGROUND

The Pipeline Embolization Device (PED) is a treatment modality for wide-neck complex intracranial aneurysms. There have been recent reports for the use of PEDs in dissecting pseudoaneurysms of the cervical carotid arteries. The use of this flow diversion technology has emerged as a promising alternative; however, there are various risks and complications that one should be aware of.

OBJECTIVE

To report a rare postoperative complication, identified during follow-up, in a patient initially treated for an internal carotid artery dissection with multiple overlapping PEDs.

METHODS

A 53-year-old male with unremarkable history presented with acute Horner's syndrome, and imaging findings revealing internal carotid artery dissection and pseudoaneurysm with significant flow-limiting stenosis. He underwent treatment with a PED.

RESULTS

At 3 months post-operation, a cerebral angiogram demonstrated that one of his pipeline stents in the posterior cavernous segment had collapsed at its central portion. Flow was preserved around the outside of the collapsed device. We performed 4 rounds of balloon angioplasty with modest, but not complete, re-expansion of the stent. The patient has been doing well in the postoperative period with no complications.

CONCLUSION

The PED's role in the management of aneurysms and other intra- and extra-cranial vascular pathologies continues to expand, and new complications are bound to be discovered, similar to our case. As the use of these devices becomes routine and widespread, the frequency of these complications will increase. The management of unforeseen complications of PEDs, such as a collapsed stent, will need to be determined on an individual basis.

Treatment of Intracranial Aneurysms With Pipeline Embolization Device: Newer Applications and Technical Advances

OPINION STATEMENT

Pipeline embolization device (PED) is a flow diverter used in the endovascular treatment of intracranial aneurysms, particularly those with unfavorable configurations. It works by causing progressive flow redirection leading to thrombosis within the aneurysm. PED was initially approved for adults with large or giant wide-necked (≥4 mm or no discernible neck) aneurysms of the internal carotid artery (ICA) from the petrous to the superior hypophyseal segments. Studies have shown a superior aneurysm occlusion rate of 85 % at 6 months for the PED and mortality ranging from 2.6 to 4 %. There appears to be a knowledge gap in terms of the duration of dual antiplatelet therapy and efficacy of assessing platelet inhibition. However, increasing operator experience and favorable longer-term outcome data have led to the exploration of PED for a wide array of off-label uses. Given the paucity of good-quality studies comparing PED with other endovascular/surgical treatment options, several multicenter randomized trials are currently underway to answer these important questions.

Flow-diverter devices in the treatment of intracranial aneurysms: A meta-analysis and systematic review

OBJECTIVE

The purpose of this report was to discuss the overall limitations, safety and efficacy of flow-diverter stenting for intracranial aneurysms.

METHODS

The authors performed a meta-analysis from January 2009 to September 2014 using the terms "flow diverter" and "intracranial aneurysms." Additional studies were identified through references in each reviewed article. Data extraction, performed independently by the authors, included demographic data, technical and clinical complications, morbidity and mortality, aneurismal occlusion rates related to flow-diverter devices. The analysis was performed using a fixed effect.

RESULTS

Twenty-nine studies with 1524 patients and three to 62 months of follow-up were identified for analysis. The overall technical failure and complication rate was 9.3% (95% CI 6%-12.6%). The rate of procedure-related complication was 14% (95% CI 10.2%-17.9%) and 6.6% (95% CI 4%-9.1%) for morbidity and mortality. Fusiform, dissecting and circumferential aneurysm (OR 3.10, 95% CI 0.93-10.37) were significant risk factors for technical failure and complication. Posterior circulation location (OR 4.03, 95% CI 2.45-6.61), peripheral location (OR 2.74, 95% CI 1.52-4.94) and fusiform, dissecting and circumferential aneurysm (OR 1.95, 95% CI 1.15-3.30) were statistically significant risk factors for procedure-related complications. Posterior circulation location (OR 4.39, 95% CI 2.44-7.90) and peripheral location (OR 3.64, 95% CI 1.74-7.62) were statistically significant risk factors for morbidity and mortality.

CONCLUSIONS

Fusiform, dissecting and circumferential aneurysm, posterior circulation and peripheral locations have greater procedure-related complications.

In-Pipeline Stenosis

BACKGROUND:

The Pipeline Embolization Device is a widely utilized flow diverter in the treatment of intracranial aneurysms.

OBJECTIVE:

To assess the incidence, clinical significance, predictors, and outcomes of in-Pipeline stenosis (IPS).

METHODS:

Angiographic studies in 139 patients treated between 2011 and 2013 were independently reviewed by 2 authors for the presence of IPS. Multivariable logistic regression analysis was conducted to determine predictors of IPS.

RESULTS:

A total of 21 (15.8%) patients demonstrated some degree of IPS during the follow-up period at a mean time point of 6.7 months (range, 3–24 months). The stenosis was mild (&lt;50%) in 11 patients, moderate (50%-75%) in 5, and severe (&gt;75%) in 6. None were symptomatic or required further intervention. Sixteen of these 22 patients (73%) had IPS detected within 6 months. IPS was noted in 7.6% (1/13) of patients with posterior circulation aneurysms vs 16.7% (21/126) of those with anterior circulation aneurysms (P = .03). The rate of IPS was 60% (3/5) in patients who did not receive aspirin vs only 14.2% (19/134) in those who received aspirin (P = .02). In multivariable analysis, no aspirin therapy (odds ratio, 10.0; 95% confidence interval, 1.4–67.7; P = .02) and internal carotid artery aneurysm location (odds ratio, 3.1; 95% confidence interval, 1.1–8.8; P = .03) were strong independent predictors of IPS.

CONCLUSION:

IPS is a common, early, and mostly benign complication. Patients with internal carotid artery aneurysms are more likely to develop IPS. Aspirin plays a key role in preventing IPS. The results of this study further support the safety of flow diverters.

Immediate procedural outcomes in 44 consecutive Pipeline Flex cases: the first North American single-center series

Background

Flow diversion is an established technique for treatment of cerebral aneurysms. The Pipeline embolization device (PED) is the only FDA-approved flow diverting stent in the USA. A second-generation device, PED Flex, has recently been released with modifications to the delivery system. Published reports of experience with this new device are limited.

Objective

To describe the initial outcomes from the first North American series using the PED Flex—a single-center experience of 44 cases.

Methods

All patients consecutively treated with the PED Flex embolization device from February 2015 through April 2015 were included in the study. Data were collected for patient demographics, aneurysm characteristics, technical procedural details, and early outcomes.

Results

PED Flex treatment was attempted in 42 patients (mean 56.6±2.0 years) with 44 aneurysms (mean size 6.5±0.6 mm), 41/44 (93%) of which were anterior circulation and 3/44 (7%) were posterior circulation. PED Flex was successfully implanted in 43/44 cases (98%). A single device was used in 41/43 cases (95%), with a mean of 1.07±0.05 devices implanted per case. Resheathing was performed in 4/44 cases (9%). Mean postprocedure hospital length of stay was 1.3±0.2 days. One significant neurological complication (2.3%) occurred, which was a stroke in a patient non-compliant with the prescribed antiplatelet regimen.

Conclusions

Pipeline Flex is a second-generation flow diverter with enhanced features compared with the first-generation PED. These modifications allow for more reliable deployment with continued improvements in procedural safety.