Treatment of Large and Giant Intracranial Aneurysms: Cost Comparison of Flow Diversion and Traditional Embolization Strategies

doi:10.1016/j.wneu.2013.02.089

World Neurosurgery

Volume 82, Issue 5, November 2014, Pages 696-701

https://doi.org/10.1016/j.wneu.2013.02.089 Get rights and content

Objective

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.

Methods

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.

Results

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.

Conclusions

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.

Introduction

Endovascular treatment of intracranial aneurysms with traditional embolic agents can be expensive. Compared with surgical clipping, endovascular treatment is associated with better clinical outcomes but higher hospital costs in both patients with ruptured and patients with unruptured aneurysms 4, 8. In addition, the total cost of endovascular treatment increases exponentially with aneurysm size. Consequently, endovascular treatment of large and giant aneurysms with traditional embolic agents can be cost prohibitive.

Flow diversion has recently emerged as a promising strategy for management of large and giant aneurysms. At an increasing number of institutions, the pipeline embolization device (PED), a dedicated flow diverter, has become a first-line treatment for aneurysms in various intracranial locations. Several recently published studies have demonstrated the relative safety and efficacy of this approach 1, 6, 9, 10, 14. Although the cost of each implant is much higher for PED compared with more traditional devices (coils and self-expanding stents), the number of implants used per procedure is smaller, resulting in significant cost savings, especially for large and giant aneurysms. A single study by Colby et al. (2) has compared the cost of aneurysm embolization with the PED vs. stent-assisted coiling and found a 25.7% procedural cost reduction with the PED. The authors, however, failed to control for decisive factors such as aneurysm volume, type of embolic agent, and number of PEDs used, all of which may significantly influence the total cost of the procedure. Their study also did not include a comparison to liquid embolic agents such as Onyx HD 500 (eV3, Irvine, California, USA).

The purpose of the current study was to determine whether treatment of large and giant aneurysms with the PED is more economical than traditional embolization strategies (coils or Onyx HD 500) using a matched-pair analysis. Cost comparison was also further stratified based on aneurysm volume, type of embolic agent, and number of PEDs used.

Section snippets

Patient Selection

The study protocol was approved by the University Institutional Review Board. We identified 30 consecutive patients with aneurysms larger than 10 mm that were successfully treated with PED at our institution between 2011 and 2012. Previously treated aneurysms were excluded from the study.

Aneurysm Volume Calculation

Thin-slice magnetic resonance angiogram (MRA) images of patients were imported into iPLAN RT Image 4.1 (BrainLAB AG, Feldkirchen, Germany). The aneurysm was identified by the senior author and contoured on the

Results

Aneurysm locations were as follows: carotid cavernous (n = 13), paraclinoid (n = 13), vertebrobasilar (n = 3), and anterior cerebral artery (n = 1). The median aneurysm volume was 0.90 cm³ (range 0.234 to 6.635 cm³). Eight aneurysms (26.7%) were smaller than 0.5 cm³, 8 (26.7%) were between 0.5 and 0.99 cm³, 4 (13.3%) were between 1 and 1.99 cm³, 6 (20%) were between 2 and 3.99 cm³, and 4 (13.3%) were ≥4 cm³.

The number of PEDs used was 1.7 on average. A single PED was used in 16 (53.3%)

Discussion

The PED is increasingly used to treat patients with large or giant aneurysms, which are often unsuitable for surgery, and for which stent-assisted coiling would require a large number of coils. The cost of coiling depends largely on aneurysm size and the number of coils placed. Because PED therapy relies on flow diversion and parent vessel reconstruction to induce aneurysm thrombosis, aneurysm size is less relevant. For this reason, the PED is thought to be cost saving in large and giant

Conclusions

The cost of initial treatment of large and giant aneurysms by flow diversion with PED is economically favorable compared to traditional embolization techniques. However, any potential cost benefit largely depends on aneurysm volume, type of embolic material, and number of PEDs used. Accordingly, the PED is not a cost-saving intervention in aneurysms smaller than 0.9 cm³ and if more than one device is used. Future studies comparing the long-term cost-effectiveness of the techniques should take

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Single center experience with pipeline stent: feasibility, technique, and complications
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Cost comparison of endovascular treatment of anterior circulation aneurysms with the pipeline embolization device and stent-assisted coiling
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Clinical and angiographic outcome after endovascular management of giant intracranial aneurysms
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Early postmarket results after treatment of intracranial aneurysms with the pipeline embolization device: a U.S. multicenter experience
Neurosurgery
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Cited by (37)

Coil Embolization with Subsequent Subacute Flow Diversion Before Hospital Discharge as a Treatment Paradigm for Ruptured Aneurysms
2022, World Neurosurgery
Citation Excerpt :
Despite half of the patients in our cohort presenting with mFisher scale 3 and 4 SAHs, there were no instances of vasospasm requiring intervention. The findings of this study have influenced our practice such that we give consideration to pursue this treatment strategy in aneurysms with the following characteristics: 1) ruptured aneurysms that may otherwise be optimally treated via flow diversion had they presented unruptured (Figure 1), 2) posterior circulation aneurysms (Figure 2), and 3) giant aneurysms of the internal carotid artery23,24 fusiform aneurysms with wide necks and/or unfavorable dome-to-neck ratios, which inherent risk of coil herniation into the parent vessel, may also benefit from this treatment paradigm as follows: neurointerventionalists can feel confident that PED flow diversion can be pursued safely during the index hospitalization, with good aneurysm occlusion rates and obviate the periprocedural morbidity associated with upfront, stand-alone treatment. This paper does have limitations, namely: the retrospective nature of the study, the limited number of patients included in the study cohort, and the lack of defined inclusion criteria of which patients may be candidates to pursue this treatment strategy.
Subtotal coil embolization followed by subsequent flow diversion is often pursued for treatment of acutely ruptured aneurysms. Owing to the need for anti-platelet therapy, the optimal time of safely pursuing flow diversion treatment has not been fully elucidated. In this study, we aim to demonstrate the safety and feasibility of staged treatment of acutely ruptured aneurysms with early coil embolization followed by flow diversion prior to discharge.
A retrospective study to evaluate clinical outcomes of patients who presented with aneurysmal subarachnoid hemorrhage and underwent coil embolization followed by subacute flow diversion treatment during the same hospitalization.
A total of 18 patients are included in our case series. Eight patients presented with Hunt-Hess (H-H) grade 2 bleed, 6 patients with H-H grade 3, and 2 patients each with H-H grade 4 and H-H grade 1. Eight patients required placement of an external ventricular drain on admission. After initial coil embolization, 12 achieved Raymond-Roy grade 2 occlusion, and 6 attained grade 3a/b occlusion. The mean duration between coil embolization and subsequent flow diversion was 9.83 days (range: 1–30). There were no instances of re-hemorrhage between initial coil embolization and subsequent flow diversion treatment. Sixteen patients had a minimum of 6-month follow-up, of which 15 were found to have complete occlusion, and 1 required subsequent clipping.
Subtotal coil embolization followed by definitive treatment using flow diversion during the same hospitalization is feasible and achieves excellent aneurysm occlusion rates while avoiding dual anti-platelet therapy during the initial hemorrhage period.
Evaluating the Effect of the Number of Wire of Flow Diverter Stents on the Nonstagnated Region Formation in an Aneurysm Sac Using Lagrangian Coherent Structure and Hyperbolic Time Analysis
2020, World Neurosurgery
Giant aneurysms at carotid arteries are typically treated with flow diverter (FD) stents in the clinic. Although the goal of an FD stent is to direct most of the blood flow into the main artery, not much is known regarding the effects of wire number an FD possesses on the hemodynamics inside the aneurysm.
In this study, 48-, 72-, and 96-wire FD stents were separately implanted into the site of aneurysm of a 45-year-old woman to evaluate the effects of the FD's number of wires on fluid flow behavior in the aneurysm sac. Time evolution of both finite-time Lyapunov exponent (FTLE) and hyperbolic time fields in the aneurysm sac were calculated by using computational fluid dynamics along with Lagrangian coherent structure (LCS) methods.
The computations reveal that a 48-wire FD stent allows a large amount of blood to enter inside the aneurysm sac revealing scattered nonstagnant flow zones formation. Besides, time-dependent results of LCS analysis show that most of the blood flow is diverted into the main artery when 72- and 96-wire number Surpass brand FD stents are separately implanted into the site of the aneurysm, yielding a small amount of blood flow to penetrate into the aneurysm sac.
Furthermore, FTLE and hyperbolic time field plots are in good agreement with the patient's digital subtraction angiography image captured 3.5 minutes after 72-wire Surpass brand FD stent implantation.
Determination of Aneurysm Volume Critical for Stability After Coil Embolization: A Retrospective Study of 3530 Aneurysms
2019, World Neurosurgery
Citation Excerpt :
Retreatment was required more frequently in the coil group than in the flow diversion group (37% vs. 2.8%, respectively; P < 0.001). In another study, the Pipeline Embolization Device was economically more favorable than traditional embolization strategies in aneurysms with large volume (>900 mm3).17 In a cost-effectiveness analysis, quality-adjusted life years were comparable between the Pipeline Embolization Device and coiling groups (12.72 vs. 12.89), but with a lower lifetime rehabilitation and treatment cost in the former group ($59,837 vs. $79,025), respectively.18
Recurrence is one of the concerns even after successful endovascular treatment of intracranial aneurysms. We sought to determine the critical aneurysm volume and risk factors related to aneurysmal stability in patients undergoing coil embolization of intracranial aneurysms.
Aneurysm volume and follow-up imaging data were retrieved in 3042 patients with 3530 aneurysms who were treated with endovascular coil embolization from January 2006 to October 2016. We analyzed the anatomic outcome in relation to aneurysm volume and determined the critical aneurysm volume favoring coil embolization.
Recanalization rates were 2.8%, 6.3%, 19.4%, and 67.4% in each group with aneurysm volume of <10, 10–100, 100–1000, and >1000 mm³, respectively. When we investigated the 100–1000 mm³ group, the recanalization rate remarkably increased at 500 mm³ (16.4% vs. 57.5%, P < 0.0001; odds ratio [OR], 6.968; 95% confidence interval [CI], 3.562–13.631). In the entire cohort, recanalization rates were significantly different between aneurysm volume of <500 and >500 mm³ (7.2% vs. 62.9%, respectively; P < 0.0001; OR, 21.848; 95% CI, 13.944–34.235). In aneurysm volumes of >500 mm³, the location was a significant prognostic factor for long-term stability (posterior circulation vs. anterior circulation; OR, 4.737; 95% CI, 1.275–17.602; P = 0.020).
In our series of cerebral aneurysms treated with coil embolization, 500 mm³ was found to be the critical volume determining stability after coil embolization. Large volume aneurysms in the posterior circulation were especially prone to recanalization after coiling.
Comparison of Flow Diversion and Coiling for the Treatment of Unruptured Intracranial Aneurysms
2019, World Neurosurgery
Citation Excerpt :
The quality for most of the included publications was high as shown in Table 1. A total of 11 articles (10 retrospective studies [RCS]11,21-24,26-30 and 1 prospective study25) were involved in our study. The overall participants of the coiling group was 611, whereas it was 576 in the flow diversion group.
To systematically assess the efficacy and safety between flow diversion and coiling for patients with unruptured intracranial aneurysms.
Potential academic articles were identified from Cochrane Library, Medline, PubMed, EMBASE, ScienceDirect, and other databases. The time range we retrieved from was the inception of electronic databases to February 2019. Gray studies were identified from the references of included literature reports. STATA version 11.0 was used to analyze the pooled data.
A total of 11 articles (10 retrospective studies and 1 prospective study) were involved in our study. The overall participants of the coiling group were 611, whereas 576 were in the flow diversion group. Our meta-analysis showed that flow diversion was preferable for unruptured intracranial aneurysms as its lower value of total cost per case (weighted mean difference, 5705.906; 95% confidence interval [CI], [4938.536, 6473236]; P < 0.001), fluoroscopy time per case (weighted mean difference, 25.786; 95% CI, 17.169–34.377; P < 0.001), and retreatment rates (odds ratio [OR], 7.127; 95% CI, [3.525, 14.410]; P < 0.001), at the same time, a higher rate of immediate completed occlusion (OR, 0.390; 95% CI, [0.224, 0.680]; P = 0.001) and follow-up completed occlusion (OR, 0.173; 95% CI, [0.080, 0.375]; P < 0.001) was demonstrated in the flow diversion group. There was no difference on intraoperative complication rates (P = 0.070), procedure-related mortality (P = 0.609) and rupture rates (P = 0.408), modified Rankin Scale (mRS) 0–2 at discharge (P = 0.077), and mRS 0–2 at follow-up (P = 0.484).
The use of flow diversion for the treatment of unruptured intracranial aneurysms may reduce total cost per case, fluoroscopy time per case, retreatment rates, and increases immediate completed occlusion and follow-up completed occlusion rates without affecting the results of mRS and intraoperative complication.
Evaluating the Effectiveness of 2 Different Flow Diverter Stents Based on the Stagnation Region Formation in an Aneurysm Sac Using Lagrangian Coherent Structure
2019, World Neurosurgery
Flow diverter stents are often used in the treatment of giant aneurysms at carotid arteries. Although these stents promise to decrease blood flow into the aneurysm sac, little is known about hemodynamics inside the aneurysm once the stent is planted into the aneurysm neck. To further explore this, computational fluid dynamics and Lagrangian coherent structure (LCS) techniques were used to evaluate the time evolution mechanism of stagnation regions inside an aneurysm. The purpose of this work is to provide a quantitative effectiveness comparison of 2 different flow diverter stents placed into the aneurysm neck based on their stagnation zone formations in the sac.
In numerical modeling, Womersley function, and fluidsolid interaction were defined as the 3 cardiac cycles for blood velocity and the aneurysm wall, respectively. Moreover, blood was accepted as a non-Newtonian fluid, and mean arterial blood pressure of the patient was entered into the computational domain to accurately mimic the hemodynamics inside the aneurysm sac accurately.
The numerical analyses revealed that the use of a Fred-type stent in the aneurysm neck causes fluid flow zone formations yielding to sequenced stagnated regions. Time evolution of stagnation regions in an aneurysm sac was shown just after a flow diverter stent was employed at a patient's aneurysm neck. Furthermore, the stagnation field in the Fred stent–fitted aneurysm was nearly 4.8 times the stagnation area of the Surpass brand stent–attached aneurysm.
Finite time Lyapunov exponent fields obtained from the LCS techniques demonstrated a good agreement with the patient's digital subtraction angiography images obtained just after treatment.
Cost Comparison of Surgical Clipping and Endovascular Coiling of Unruptured Intracranial Aneurysms: A Systematic Review
2019, World Neurosurgery
Citation Excerpt :
Still, 6 out of 8 authors observed higher costs for endovascular coiling. A study by el-Chalouhi et al.24 suggests an exponential growth of total costs of the endovascular treatment depending on the aneurysm size. The cause for this could be in the high material costs of the detachable coils combined with the fact that the aneurysm must be filled with coils.
Rupture of unruptured intracranial aneurysms (UIA) is the main cause for subarachnoid hemorrhage. UIA are widespread among the population. Advanced technology enables us to diagnose UIAs with increasing reliability and subsequently treat them. There are 2 main treatment options: surgical clipping and endovascular treatment of the aneurysm. This article aims to analyze costs of neurosurgical clipping and the endovascular approach to treat UIA, and to give an overview over the existing literature.
A systematic literature search was conducted using the databases Ovid MEDLINE, PubMed, and NHS EED. Articles were divided into 2 groups based on the perspective from which costs were evaluated (health care provider or payer). Costs were inflated to the year 2015 and converted to international dollars.
The literature search yielded 137 different articles out of which 15 have been considered relevant and have been included in this review. Not only absolute numbers but also the cost ratio of both treatment modalities showed substantial variations. The coiling procedure tends to be more expensive for health care providers but cheaper for cost bearers. Without any exception, the authors determined shorter lengths of stay for patients who underwent the coiling procedure.
Due to different definitions of hospital costs and hardly reproducible calculations, comparability of the stated numbers is limited. Besides the economic impact, outcomes must be considered when making a treatment decision. The 2 treatment modalities are not equally suitable in every patient nor for every aneurysm location.

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: 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 ReportTreatment of Large and Giant Intracranial Aneurysms: Cost Comparison of Flow Diversion and Traditional Embolization Strategies

Objective

Methods

Results

Conclusions

Introduction

Section snippets

Patient Selection

Aneurysm Volume Calculation

Results

Discussion

Conclusions

World Neurosurg

Single center experience with pipeline stent: feasibility, technique, and complications

Neurosurgery

Cost comparison of endovascular treatment of anterior circulation aneurysms with the pipeline embolization device and stent-assisted coiling

Neurosurgery

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

Neurosurgery

The effect of coiling vs. clipping of ruptured and unruptured cerebral aneurysms on length of stay, hospital cost, hospital reimbursement, and surgeon reimbursement at the university of Florida

Neurosurgery

Clinical and angiographic outcome after endovascular management of giant intracranial aneurysms

Neurosurgery

Early postmarket results after treatment of intracranial aneurysms with the pipeline embolization device: a U.S. multicenter experience

Neurosurgery

Peer-Review Report
Treatment of Large and Giant Intracranial Aneurysms: Cost Comparison of Flow Diversion and Traditional Embolization Strategies