Current Status of Pipeline Embolization Device in the Treatment of Intracranial Aneurysms: A Review

doi:10.1016/j.wneu.2012.09.023

World Neurosurgery

Volume 80, Issue 6, December 2013, Pages 829-835

https://doi.org/10.1016/j.wneu.2012.09.023 Get rights and content

Objective

Pipeline embolization device (PED) implantation is a novel endovascular treatment option for the treatment of intracranial aneurysms. It is emerging as a useful alternative to coiling and to open surgery, and its use is increasing worldwide. We performed a literature review to examine its efficacy, technical challenges, and safety.

Methods

PubMed database was used to identify all articles relating to PED.

Results

The review outlines the indications for PED, its technical aspects, complications, and clinical outcomes.

Conclusions

PED offers an alternative to endovascular coiling for aneurysms with complex morphology. The indication for its use has evolved from the limited scope of treatment of giant aneurysms with wide necks to the inclusion of smaller aneurysms. The procedural safety profile of PED is comparable with or possibly superior to balloon-remodeling or stent-assisted coil embolization in specific circumstances. However, questions remain regarding the incidence of post-procedural subarachnoid hemorrhage. Ongoing monitoring and meticulous documentation of PED postimplantation safety is strongly recommended.

Introduction

The treatment of endovascular aneurysm has evolved considerably during the past two decades, with coiling emerging as the treatment of choice for a significant proportion of saccular aneurysms (17). The International Study of Subarachnoid Aneurysm Treatment (24) and the Barrow Ruptured Aneurysm Trial (23) have established the advantages of endovascular treatment in selected clinical scenarios. However, a considerable number of aneurysms are not amendable to coiling.

Balloon remodeling and stent-assisted techniques were developed in mid-1990s and early 2000, rendering more feasible the treatment of aneurysms with more complex morphology (17).

Despite the technological advances, wide-neck and giant saccular or fusiform aneurysms present considerable challenges for the operator (13). Parent artery occlusion is one of the earliest endovascular techniques that showed efficacy treatment for unclippable giant aneurysms. However, parent artery occlusion depends on patient tolerance to occlusion, and reliable predictors for ischemic events are lacking. (13) Furthermore, successful balloon occlusion test does not preclude delayed ischemic complications that occur between 4% and 15% of cases. (13) Endovascular treatments frequently fail to produce complete occlusion in such aneurysms (1).

Recurrence of the treated aneurysm postendovascular treatment occurs in 9% to 34% cases 1, 3, 4, 5, 25, 30. Incomplete occlusion, larger (>10 mm) aneurysm size, and neck size are risk factors for recurrence 1, 3, 4, 5, 25, 30. These aneurysms are prone to coil compaction and recanalization, even when complete or near-complete occlusion has been achieved after the initial embolization, and require extended imaging surveillance and the possibility of retreatment 12, 24, 25, 35. Failure of endovascular techniques to achieve a complete and durable occlusion of aneurysms has been attributed to several factors, including limitations with respect to the volumetric packing of the aneurysm sac with coils, inherent difficulties associated with achieving a continuous reconstruction of large complex aneurysm neck defects with coils, and finally a fundamental failure of the endovascular strategy to address the underlying diseased parent vessel (9).

Section snippets

Literature Review

A search for published articles on pipeline embolization devices (PED) in PubMed between 2000 and February 2012 was performed. A total of 210 patients with 241 aneurysms treated with PED were identified in five reported case series. A detail review on the indications, therapeutic results, and technical and safety issues of PED was performed.

Principle of Flow Diversion

Flow diversion offers a fundamentally novel treatment approach. This approach potentially represents a more physiologic treatment of intracranial aneurysms

PED

PED (ev3, Irvine, California, USA) is a flexible self-expanding, microcatheter-delivered, high-metal-surface-area coverage, stent-like device designed to achieve aneurysm occlusion through the endoluminal reconstruction of the diseased segment of the parent artery that gives rise to the aneurysm (Figure 1). Composed of 48 individual cobalt chromium and platinum strands, it provides 30% to 35% metal surface area coverage when fully deployed (10), in comparison with only 6% to 9.5% coverage with

Aneurysm Selection and Limitations

With larger patient series being published recently, confirming the efficacy of the device and its safety profile, the use of PED has transformed during the past few years from a novel, investigational device reserved for otherwise-untreatable lesions to a more established alternative technique that is being integrated into routine cerebrovascular practice (6). A transition in the use of PED in treating large and giant aneurysms to include small- to medium-sized aneurysms has been observed.

Conclusion

PED offers an alternative to endovascular coiling for aneurysms with complex morphology. The indication for its use has evolved from giant aneurysms with wide necks to small aneurysms. The safety profile of PED is comparable with or possibly superior to balloon-remodeling or stent-assisted coil embolization in specific circumstances. However, questions remain regarding the long-term safety, treatment results, and clinical outcomes. Continued ongoing research and monitoring of the usage of PED

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Clinical and angiographic long-term follow-up of completely coiled intracranial aneurysms using endovascular technique
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Very late thrombosis of a Pipeline embolization device construct: case report
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Curative reconstruction of a giant midbasiar trunk aneurysm with the Pipeline embolization device

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Curative cerebrovascular reconstruction with the Pipeline embolization device: the emergence of definitive endovaswith the Pipeline embolization device: the emergence of definitive endovascular therapy for intracranial aneurysms

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Definitive reconstruction of circumferential, fusiform intracranial aneurysms with the pipeline embolization device

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Challenges in the endovascular treatment of giant intracranial aneurysms

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A new endoluminal, flow-disrupting device for treatment of saccular aneurysm

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A second-generation, endoluminal, flow-disrupting device for treatment of saccular aneurysms

Am J Neuroradiol

(2009)

Cited by (29)

Evolution of open surgery for unruptured intracranial aneurysms over a fifteen year period–increased difficulty and morbidity
2023, Journal of Clinical Neuroscience
The approach to intervention for unruptured intracranial aneurysms (UIAs) remains controversial. Utilization of endovascular techniques for aneurysm repair increased dramatically during the last decade. We sought to analyze recent national trends for electively treated (open and endovascular) UIAs focusing on pre-existing patient disease burden and intervention modality selection.
The Nationwide Inpatient Sample (NIS) national database was used to identify patients with primary diagnosis codes of unruptured intracranial aneurysm between 1999 and 2014. Patients were dichotomized by intervention into endovascular or open surgical treatment. Analysis of pre-existing disease severity were calculated using the Elixhauser comorbidity index. Complications of combined peri-procedural stroke or death during admission and hospital length of stay were used as primary endpoints for comparison.
The percent of total UIAs treated electively with open approach decreased from more than 95 % of cases in 1999 to less than 25 % in 2014. Patients undergoing clipping were 3 years younger than those in the endovascular group (p < 0.001). The rate of primary endpoint complications (stroke and death) and length of stay for open cases saw a decrease throughout the study but remained statistically higher when compared to the endovascular group over the study period (p < 0.001). Additionally, non-neurologic complications increased over the time period for open cases. The average preoperative co-morbid disease severity for all groups treated increased over this interval. Conversely, the relative volume of endovascular cases increased but the rate of complications and average group disease remained statistically lower than the surgical clipping group (p < 0.05).
The percent of UIAs treated electively with open approach has decreased since 1999 with a concomitant increase in complication rate in particular compared to endovascular cases. However, the health characteristics of patients treated with surgical clipping show an increase in severity of pre-existing co-morbidities. Further research into factors contributing to this finding, including potential socioeconomic differences and changes in surgeon experience are needed.
Magnetic Resonance Imaging Safety of Retained Tip and Protective Coils after Faulty Deployment of an Intracranial Pipeline Embolization Device: A Case Report
2019, World Neurosurgery
Citation Excerpt :
With the advent of new endovascular devices and techniques, the treatment of intracranial aneurysms remains an ever-evolving field, and coiling has become a feasible treatment option for most saccular aneurysms.1
The development of flow-diverters such as the Pipeline embolization device (PED) have allowed for safe and effective treatment of challenging and/or previously untreatable intracranial aneurysms. A rare but serious complication during PED deployment involves fracture of single or multiple components, which can lead to retained hardware. To date, there are little data regarding the safety of performing magnetic resonance imaging (MRI) when tip or capture coils remain intracranially.
To the best of our knowledge, we present the first case demonstrating the safe completion of MRI after treatment of 2 posterior circulation aneurysms in a woman aged 69 years presenting with subarachnoid hemorrhage whose treatment was complicated by fracture and subsequent retention of the PED tip and capture coils.
MRI (1.5T) appears safe and effective in patients who have retained PED tips and/or capture coils.
Predicting Successful Treatment of Intracranial Aneurysms with the Pipeline Embolization Device Through Meta-Regression
2018, World Neurosurgery
Citation Excerpt :
While examining hemodynamics of SAC for the containment of coils within the dome of challenging IA morphologies and for the prevention of coil herniation into parent arteries, researchers discovered, by chance, that placement of a stent by itself can lead to flow diversion and eventual obliteration of the IA.2,4 Conventional self-expanding stents previously designed to assist with mechanical retention of coils within IAs (Neuroform [Stryker, Kalamazoo, Michigan, USA], Enterprise [Codman & Shurtleff, Raynham Massachusetts, USA]) were limited in terms of flow-diverting capacity because of their high porosity and were not effective as stand-alone devices.1,5 However, when combinations of stents were used to decrease stent porosity and increase metal surface area, a significant hemodynamic effect was observed.1
To conduct meta-regression for the identification of clinically meaningful characteristics that can predict successful treatment of intracranial aneurysms with the Pipeline Embolization Device (PED).
Using the key word “Pipeline Embolization Device” and prespecified eligibility criteria, we searched PubMed and EMBASE and identified 105 original research articles (10,813 patients) published or in press (April 6, 2011, to December 31, 2016) focused on safety and/or effectiveness of PED. We constructed meta-regression models to identify predictors of 3 measures of PED treatment success, specifically rates of aneurysm occlusion, modified Rankin Scale score, and death. Rates were log_e-transformed, and the adjusted R² statistic was reported for each model.
Aneurysm morphology and type accounted for substantial variation in 1-year aneurysm occlusion rate (14 studies with 689 patients; R_adj² = 88.91%). By contrast, predictors of 6-months aneurysm occlusion rate (aneurysm location, aneurysm type; 24 studies with 1321 patients; R_adj² = 31.67%) and aneurysm occlusion rate at unspecified follow-up time (year of publication, mean duration of angiographic follow-up; 34 studies with 1663 patients, R_adj² = 42.82%) accounted for less variability. Few predictors were identified for death rate (number of patients, aneurysm morphology; 34 studies with 6463 patients, R_adj² = 50.69%) or modified Rankin Scale score ≤2 (year of publication, mean age, aneurysm morphology; 14 studies with 556 patients, R_adj² = 100%).
Few clinically meaningful characteristics appear to be relevant as predictors of the selected measures of PED treatment success. Future studies should attempt to identify additional predictors while focusing on aneurysm morphology as a key predictor of PED outcomes.
Treatment of large and giant intracranial aneurysms: Cost comparison of flow diversion and traditional embolization strategies
2014, World Neurosurgery
Citation Excerpt :
There are several other factors that should be taken into account when comparing relative costs of PED therapy with traditional embolization strategies. Aneurysms treated with flow diverters achieve a much higher rate of complete angiographic obliteration and are less likely to require further intervention compared with standard endovascular techniques (7, 10, 13). This would unquestionably translate to long-term cost savings for those treated with the PED.
Flow diversion has emerged as a promising strategy for management of intracranial aneurysms. The purpose of this study was to determine whether treatment of large and giant aneurysms with the pipeline embolization device (PED) is more economical than traditional embolization strategies.
We identified 30 consecutive aneurysms larger than 10 mm that were treated with PED at our institution. For each aneurysm treated with PED, theoretical coil embolization was performed by filling volume in a consistent, stepwise fashion until a packing density of 25% was reached. Prices of all equipment and implants were taken from price lists provided by each manufacturer.
Median aneurysm volume was 0.90 cm³. Overall procedure cost was lower with the PED (mean, $23,911) vs. coiling ($30,522, P = .06). Above the median aneurysm volume, PED treatment was significantly less expensive than coiling even if multiple PEDs were used (P = .006). However, below the median aneurysm volume, PED treatment was significantly more expensive than coiling (P = .009). Treatment with multiple PEDs was not cost-beneficial compared with coiling, even above the median aneurysm volume. Potential savings associated with the PED were highly dependent on the type of embolic agent used.
The cost of initial treatment of large and giant aneurysms with PED is economically favorable compared to traditional embolization techniques. However, any potential cost benefit depends on aneurysm volume, coil type, and number of PEDs used. Accordingly, PED therapy is more expensive than coiling in aneurysms <0.9 cm³ or when multiple devices are used.
Intracerebral hemorrhage after pipeline embolization: Management of antiplatelet agents and the case for point-of-care testing - Case reports and review of literature
2014, Clinical Neurology and Neurosurgery
Development of normal pressure hydrocephalus after the placement of a pipeline embolization device for the treatment of a large aneurysm: Case report
2014, Clinical Neurology and Neurosurgery
Citation Excerpt :
The major complications reported have included intracranial hemorrhage, thromboembolic events, perforator occlusion, in-stent thrombosis, mechanical delivery problems and aneurysm rupture [2,4–7,13,14]. However, PED is now widely used in other patients who do not strictly match the criteria of PUFS study [5,7,8]. Recent reports have mentioned unique and unusual complications, such as embolic retinal venous occlusion and shortening/migration of the PED itself [8,9].

View all citing articles on Scopus

: Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Peer-Review ReportCurrent Status of Pipeline Embolization Device in the Treatment of Intracranial Aneurysms: A Review

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Literature Review

Principle of Flow Diversion

PED

Aneurysm Selection and Limitations

Conclusion

World Neursurg

J Stroke Cerebrovasc Dis

J Neuroradiol

Retreatment of ruptured cerebral aneurysms in patients randomized by coiling or clipping in the International Subarachnoid Aneurysm Trial (ISAT)

Stroke

Aneurysm rupture following treatment with flow-diverting stents: computational hemodynamics analysis of treatment

Am J Neuroradiol

Clinical and angiographic long-term follow-up of completely coiled intracranial aneurysms using endovascular technique

J Neurosurg

Coiling of intracranial aneurysms: a systematic review on initial occlusion and reopening and retreatment rates

Stroke

Late reopening of adequately coiled intracranial aneurysms: frequency and risk factors in 400 patients with 440 aneurysms

Stroke

Pipeline in clinical practice in 2011

Neuroradiology

Very late thrombosis of a Pipeline embolization device construct: case report

Neurosurgery

Curative reconstruction of a giant midbasiar trunk aneurysm with the Pipeline embolization device

Neurosurgery

Curative cerebrovascular reconstruction with the Pipeline embolization device: the emergence of definitive endovaswith the Pipeline embolization device: the emergence of definitive endovascular therapy for intracranial aneurysms

J Neurointerv Surg

Definitive reconstruction of circumferential, fusiform intracranial aneurysms with the pipeline embolization device

Neurosurg

Aguilar Perez M, Schmid E, Hopf N, Bäzner H, Henkes H: Pipeline embolization device (PED) for neurovascular reconstruction: initial experience in the treatment of 101 intracranial aneurysms and dissections

Neuroradiology

Guglielmi detachable coil treatment of ruptured saccular cerebral aneurysms: Retrospective review of a 10-year single center experience

Am J Neuroradiol

Challenges in the endovascular treatment of giant intracranial aneurysms

Neurosurgy

A new endoluminal, flow-disrupting device for treatment of saccular aneurysm

Stroke

A second-generation, endoluminal, flow-disrupting device for treatment of saccular aneurysms

Am J Neuroradiol

Peer-Review Report
Current Status of Pipeline Embolization Device in the Treatment of Intracranial Aneurysms: A Review