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1.  Coil Embolization for Intracranial Aneurysms 
Executive Summary
Objective
To determine the effectiveness and cost-effectiveness of coil embolization compared with surgical clipping to treat intracranial aneurysms.
The Technology
Endovascular coil embolization is a percutaneous approach to treat an intracranial aneurysm from within the blood vessel without the need of a craniotomy. In this procedure, a microcatheter is inserted into the femoral artery near the groin and navigated to the site of the aneurysm. Small helical platinum coils are deployed through the microcatheter to fill the aneurysm, and prevent it from further expansion and rupture. Health Canada has approved numerous types of coils and coil delivery systems to treat intracranial aneurysms. The most favoured are controlled detachable coils. Coil embolization may be used with other adjunct endovascular devices such as stents and balloons.
Background
Intracranial Aneurysms
Intracranial aneurysms are the dilation or ballooning of part of a blood vessel in the brain. Intracranial aneurysms range in size from small (<12 mm in diameter) to large (12–25 mm), and to giant (>25 mm). There are 3 main types of aneurysms. Fusiform aneurysms involve the entire circumference of the artery; saccular aneurysms have outpouchings; and dissecting aneurysms have tears in the arterial wall. Berry aneurysms are saccular aneurysms with well-defined necks.
Intracranial aneurysms may occur in any blood vessel of the brain; however, they are most commonly found at the branch points of large arteries that form the circle of Willis at the base of the brain. In 85% to 95% of patients, they are found in the anterior circulation. Aneurysms in the posterior circulation are less frequent, and are more difficult to treat surgically due to inaccessibility.
Most intracranial aneurysms are small and asymptomatic. Large aneurysms may have a mass effect, causing compression on the brain and cranial nerves and neurological deficits. When an intracranial aneurysm ruptures and bleeds, resulting in a subarachnoid hemorrhage (SAH), the mortality rate can be 40% to 50%, with severe morbidity of 10% to 20%. The reported overall risk of rupture is 1.9% per year and is higher for women, cigarette smokers, and cocaine users, and in aneurysms that are symptomatic, greater than 10 mm in diameter, or located in the posterior circulation. If left untreated, there is a considerable risk of repeat hemorrhage in a ruptured aneurysm that results in increased mortality.
In Ontario, intracranial aneurysms occur in about 1% to 4% of the population, and the annual incidence of SAH is about 10 cases per 100,000 people. In 2004-2005, about 660 intracranial aneurysm repairs were performed in Ontario.
Treatment of Intracranial Aneurysms
Treatment of an unruptured aneurysm attempts to prevent the aneurysm from rupturing. The treatment of a ruptured intracranial aneurysm aims to prevent further hemorrhage. There are 3 approaches to treating an intracranial aneurysm.
Small, asymptomatic aneurysms less than 10 mm in diameter may be monitored without any intervention other than treatment for underlying risk factors such as hypertension.
Open surgical clipping, involves craniotomy, brain retraction, and placement of a silver clip across the neck of the aneurysm while a patient is under general anesthesia. This procedure is associated with surgical risks and neurological deficits.
Endovascular coil embolization, introduced in the 1990s, is the health technology under review.
Literature Review
Methods
The Medical Advisory Secretariat searched the International Health Technology Assessment (INAHTA) Database and the Cochrane Database of Systematic Reviews to identify relevant systematic reviews. OVID Medline, Medline In-Process and Other Non-Indexed Citations, and Embase were searched for English-language journal articles that reported primary data on the effectiveness or cost-effectiveness of treatments for intracranial aneurysms, obtained in a clinical setting or analyses of primary data maintained in registers or institutional databases. Internet searches of Medscape and manufacturers’ databases were conducted to identify product information and recent reports on trials that were unpublished but that were presented at international conferences. Four systematic reviews, 3 reports on 2 randomized controlled trials comparing coil embolization with surgical clipping of ruptured aneurysms, 30 observational studies, and 3 economic analysis reports were included in this review.
Results
Safety and Effectiveness
Coil embolization appears to be a safe procedure. Complications associated with coil embolization ranged from 8.6% to 18.6% with a median of about 10.6%. Observational studies showed that coil embolization is associated with lower complication rates than surgical clipping (permanent complication 3-7% versus 10.9%; overall 23% versus 46% respectively, p=0.009). Common complications of coil embolization are thrombo-embolic events (2.5%–14.5%), perforation of aneurysm (2.3%–4.7%), parent artery obstruction (2%–3%), collapsed coils (8%), coil malposition (14.6%), and coil migration (0.5%–3%).
Randomized controlled trials showed that for ruptured intracranial aneurysms with SAH, suitable for both coil embolization and surgical clipping (mostly saccular aneurysms <10 mm in diameter located in the anterior circulation) in people with good clinical condition:Coil embolization resulted in a statistically significant 23.9% relative risk reduction and 7% absolute risk reduction in the composite rate of death and dependency compared to surgical clipping (modified Rankin score 3–6) at 1-year.
The advantage of coil embolization over surgical clipping varies widely with aneurysm location, but endovascular treatment seems beneficial for all sites.
There were less deaths in the first 7 years following coil embolization compared to surgical clipping (10.8% vs 13.7%). This survival benefit seemed to be consistent over time, and was statistically significant (log-rank p= 0.03).
Coil embolization is associated with less frequent MRI-detected superficial brain deficits and ischemic lesions at 1-year.
The 1- year rebleeding rate was 2.4% after coil embolization and 1% for surgical clipping. Confirmed rebleeding from the repaired aneurysm after the first year and up to year eight was low and not significantly different between coil embolization and surgical clipping (7 patients for coil embolization vs 2 patients for surgical clipping, log-rank p=0.22).
Observational studies showed that patients with SAH and good clinical grade had better 6-month outcomes and lower risk of symptomatic cerebral vasospasm after coil embolization compared to surgical clipping.
For unruptured intracranial aneurysms, there were no randomized controlled trials that compared coil embolization to surgical clipping. Large observational studies showed that:
The risk of rupture in unruptured aneurysms less than 10 mm in diameter is about 0.05% per year for patients with no pervious history of SAH from another aneurysm. The risk of rupture increases with history of SAH and as the diameter of the aneurysm reaches 10 mm or more.
Coil embolization reduced the composite rate of in hospital deaths and discharge to long-term or short-term care facilities compared to surgical clipping (Odds Ratio 2.2, 95% CI 1.6–3.1, p<0.001). The improvement in discharge disposition was highest in people older than 65 years.
In-hospital mortality rate following treatment of intracranial aneurysm ranged from 0.5% to 1.7% for coil embolization and from 2.1% to 3.5% for surgical clipping. The overall 1-year mortality rate was 3.1% for coil embolization and 2.3% for surgical clipping. One-year morbidity rate was 6.4% for coil embolization and 9.8% for surgical clipping. It is not clear whether these differences were statistically significant.
Coil embolization is associated with shorter hospital stay compared to surgical clipping.
For both ruptured and unruptured aneurysms, the outcome of coil embolization does not appear to be dependent on age, whereas surgical clipping has been shown to yield worse outcome for patients older than 64 years.
Angiographic Efficiency and Recurrences
The main drawback of coil embolization is its low angiographic efficiency. The percentage of complete aneurysm occlusion after coil embolization (27%–79%, median 55%) remains lower than that achieved with surgical clipping (82%–100%). However, about 90% of coiled aneurysms achieve near total occlusion or better. Incompletely coiled aneurysms have been shown to have higher aneurysm recurrence rates ranging from 7% to 39% for coil embolization compared to 2.9% for surgical clipping. Recurrence is defined as refilling of the neck, sac, or dome of a successfully treated aneurysm as shown on an angiogram. The long-term clinical significance of incomplete occlusion following coil embolization is unknown, but in one case series, 20% of patients had major recurrences, and 50% of these required further treatment.
Long-Term Outcomes
A large international randomized trial reported that the survival benefit from coil embolization was sustained for at least 7 years. The rebleeding rate between year 2 and year 8 following coil embolization was low and not significantly different from that of surgical clipping. However, high quality long-term angiographic evidence is lacking. Accordingly, there is uncertainty about long-term occlusion status, coil durability, and recurrence rates. While surgical clipping is associated with higher immediate procedural risks, its long-term effectiveness has been established.
Indications and Contraindications
Coil embolization offers treatment for people at increased risk for craniotomy, such as those over 65 years of age, with poor clinical status, or with comorbid conditions. The technology also makes it possible to treat surgical high-risk aneurysms.
Not all aneurysms are suitable for coil embolization. Suitability depends on the size, anatomy, and location of the aneurysm. Aneurysms more than 10 mm in diameter or with an aneurysm neck greater than or equal to 4 mm are less likely to achieve total occlusion. They are also more prone to aneurysm recurrences and to complications such as coil compaction or parent vessel occlusion. Aneurysms with a dome to neck ratio of less than 1 have been shown to have lower obliteration rates and poorer outcome following coil embolization. Furthermore, aneurysms in the middle cerebral artery bifurcation are less suitable for coil embolization. For some aneurysms, treatment may require the use of both coil embolization and surgical clipping or adjunctive technologies, such as stents and balloons, to obtain optimal results.
Diffusion
Information from 3 countries indicates that coil embolization is a rapidly diffusing technology. For example, it accounted for about 40% of aneurysm treatments in the United Kingdom.
In Ontario, coil embolization is an insured health service, with the same fee code and fee schedule as open surgical repair requiring craniotomy. Other costs associated with coil embolization are covered under hospitals’ global budgets. Utilization data showed that in 2004-2005, coil embolization accounted for about 38% (251 cases) of all intracranial aneurysm repairs in the province. With the 2005 publication of the positive long-term survival data from the International Subarachnoid Aneursym Trial, the pressure for diffusion will likely increase.
Economic Analysis
Recent economic studies show that treatment of unruptured intracranial aneurysms smaller than 10 mm in diameter in people with no previous history of SAH, either by coil embolization or surgical clipping, would not be effective or cost-effective. However, in patients with aneurysms that are greater than or equal to 10 mm or symptomatic, or in patients with a history of SAH, treatment appears to be cost-effective.
In Ontario, the average device cost of coil embolization per case was estimated to be about $7,500 higher than surgical clipping. Assuming that the total number of intracranial aneurysm repairs in Ontario increases to 750 in the fiscal year of 2007, and assuming that up to 60% (450 cases) of these will be repaired by coil embolization, the difference in device costs for the 450 cases (including a 15% recurrence rate) would be approximately $3.8 million. This figure does not include capital costs (e.g. $3 million for an angiosuite), additional human resources required, or costs of follow-up. The increase in expenditures associated with coil embolization may be offset partially, by shorter operating room times and hospitalization stays for endovascular repair of unruptured aneurysms; however, the impact of these cost savings is probably not likely to be greater than 25% of the total outlay since the majority of cases involve ruptured aneurysms. Furthermore, the recent growth in aneurysm repair has predominantly been in the area of coil embolization presumably for patients for whom surgical clipping would not be advised; therefore, no offset of surgical clipping costs could be applied in such cases. For ruptured aneurysms, downstream cost savings from endovascular repair are likely to be minimal even though the savings for individual cases may be substantial due to lower perioperative complications for endovascular aneurysm repair.
Guidelines
The two Guidance documents issued by the National Institute of Clinical Excellence (UK) in 2005 support the use of coil embolization for both unruptured and ruptured (SAH) intracranial aneurysms, provided that procedures are in place for informed consent, audit, and clinical governance, and that the procedure is performed in specialist units with expertise in the endovascular treatment of intracranial aneurysms.
Conclusion
For people in good clinical condition following subarachnoid hemorrhage from an acute ruptured intracranial aneurysm suitable for either surgical clipping or endovascular repair, coil embolization results in improved independent survival in the first year and improved survival for up to seven years compared to surgical clipping. The rebleeding rate is low and not significantly different between the two procedures after the first year. However, there is uncertainty regarding the long-term occlusion status, durability of the stent graft, and long-term complications.
For people with unruptured aneurysms, level 4 evidence suggests that coil embolization may be associated with comparable or less mortality and morbidity, shorter hospital stay, and less need for discharge to short-term rehabilitation facilities. The greatest benefit was observed in people over 65 years of age. In these patients, the decision regarding treatment needs to be based on the assessment of the risk of rupture against the risk of the procedure, as well as the morphology of the aneurysm.
In people who require treatment for intracranial aneurysm, but for whom surgical clipping is too risky or not feasible, coil embolization provides survival benefits over surgical clipping, even though the outcomes may not be as favourable as in people in good clinical condition and with small aneurysms. The procedure may be considered under the following circumstances provided that the aneurysm is suitable for coil embolization:
Patients in poor/unstable clinical or neurological state
Patients at high risk for surgical repair (e.g. people>age 65 or with comorbidity), or
Aneurysm(s) with poor accessibility or visibility for surgical treatment due to their location (e.g. ophthalmic or basilar tip aneurysms)
Compared to small aneurysms with a narrow neck in the anterior circulation, large aneurysms (> 10 mm in diameter), aneurysms with a wide neck (>4mm in diameter), and aneurysms in the posterior circulation have lower occlusion rates and higher rate of hemorrhage when treated with coil embolization.
The extent of aneurysm obliteration after coil embolization remains lower than that achieved with surgical clipping. Aneurysm recurrences after successful coiling may require repeat treatment with endovascular or surgical procedures. Experts caution that long-term angiographic outcomes of coil embolization are unknown at this time. Informed consent for and long-term follow-up after coil embolization are recommended.
The decision to treat an intracranial aneurysm with surgical clipping or coil embolization needs to be made jointly by the neurosurgeon and neuro-intervention specialist, based on the clinical status of the patient, the size and morphology of the aneurysm, and the preference of the patient.
The performance of endovascular coil embolization should take place in centres with expertise in both neurosurgery and endovascular neuro-interventions, with adequate treatment volumes to maintain good outcomes. Distribution of the technology should also take into account that patients with SAH should be treated as soon as possible with minimal disruption.
PMCID: PMC3379525  PMID: 23074479
2.  Y-Stenting Endovascular Treatment for Ruptured Intracranial Aneurysms : A Single-Institution Experience in Korea 
Objective
Stent-assisted coiling on intracranial aneurysm has been considered as an effective technique and has made the complex aneurysms amenable to coiling. To achieve reconstruction of intracranial vessels with preservation of parent artery the use of stents has the greatest potential for assisted coiling. We report the results of our experiences in ruptured wide-necked intracranial aneurysms using Y-stent coiling.
Methods
From October 2003 to October 2011, 12 patients (3 men, 9 women; mean age, 62.6) harboring 12 complex ruptured aneurysms (3 middle cerebral artery, 9 basilar tip) were treated by Y-stent coiling by using self-expandable intracranial stents. Procedural complications, clinical outcome, and initial and midterm angiographic results were evaluated. The definition of broad-necked aneurysm is neck diameter over than 4 mm or an aneurysm with a neck diameter smaller than 4 mm in which the dome/neck ratio was less than 2.
Results
In all patients, the aneurysm was successfully occluded with no apparent procedure-related complication. There was no evidence of thromboembolic complication, arterial dissection and spasm during procedure. Follow-up studies showed stable and complete occlusion of the aneurysm in all patients with no neurologic deficits.
Conclusion
The present study did show that the Y-stent coiling seemed to facilitate endovascular treatment of ruptured wide-necked intracranial aneurysms. More clinical data with longer follow-up are needed to establish the role of Y-stent coiling in ruptured aneurysms.
doi:10.3340/jkns.2012.52.3.187
PMCID: PMC3483317  PMID: 23115659
Intervention; Stent; Subarachnoid hemorrhage
3.  Endovascular Coil Occlusion of Intracranial Aneurysms Assisted by a Novel Self-Expandable Nitinol Microstent (Neuroform) 
Interventional Neuroradiology  2004;8(2):107-119.
Summary
Endovascular treatment of wide neck intracranial aneurysms is technically difficult and leads to less favorable treatment results and long term outcome. We participated in a multicenter prospective study to evaluate the safety and performance of a new self-expandable nitinol micro stent (Neuroform) in stent assisted coil occlusion of wide neck intracranial aneurysms. Eighteen patients were enrolled in the study in a single center. The anatomy of the target aneurysm and the parent vessel, technical details of the procedure, device functionality, anatomic and clinical results were evaluated. All enrolled aneurysms were either wide necked or showed an unfavorable neck-to-fundus ratio. In 16 out of 18 patients the Neuroform device allowed stent assisted coil occlusion of the aneurysm. The occlusion rate was 95% in eight patients and 100% in eight patients. The two failures were both due to anatomic reasons. Flexibility of the stent, behavior during deployment and subsequent ability to retain coils within the aneurysmal sac were considered as good as or better than the properties of previous balloon expandable stents. No device-related adverse events were encountered. Procedure-related clinical complications occurred in seven patients but caused no severe permanent neurological deficit. The Neuroform neurovascular stenting system is a safe and effective adjunct for the stent-assisted coil occlusion of wide necked intracranial aneurysms. The major advantages of this device are its self-expanding property and very high flexibility which allows safe navigation, easy sizing, as well as accurate positioning of the stent while providing sufficient bridging of the aneurysm neck for subsequent coil placement.
PMCID: PMC3576604  PMID: 20594519
intracranial aneurysm, electrolytically detachable coil, intracranial stent, nitinol, embolization, internal carotid artery, vertebral artery, basilar artery
4.  Endovascular Treatment of Wide-Necked Intracranial Aneurysms : Techniques and Outcomes in 15 Patients 
Objective
It is technically difficult to treat wide-necked intracranial aneurysms by the endovascular method. Various tools and techniques have been introduced to overcome the related technical limitations. The purpose of this study was to evaluate the radiologic and clinical results of wide-necked intracranial aneurysm treatment using the endovascular method.
Methods
Fifteen aneurysms in 15 patients were treated by the endovascular method from October 2009 to August 2010. Seven patients presented with subarachnoid hemorrhage (SAH), seven patients had unruptured aneurysms, and one patient had an intracerebral hemorrhage and intraventricular hemorrhage due to an incompletely clipped aneurysm. The mean dome-to-neck ratio was 1.1 (range, 0.6-1.7) and the mean height-to-neck ratio was 1.1 (range, 0.6-2.0). We used double microcatheters instead of a stent or a balloon for the first trial. When we failed to make a stable coil frame with two coils, we used a stent-assisted technique.
Results
All aneurysms were successfully embolized. Eleven aneurysms (73%) were embolized by the double microcatheter technique without stent insertion, and four aneurysms (27%) were treated by stent-assisted coil embolization. One case had subclinical procedure-related intraoperative hemorrhage. Another case had procedure-related thromboembolism in the left distal anterior cerebral artery. During the follow-up period, one patient (7%) had a recanalized aneurysmal neck 12 months after coil embolization. The recurrent aneurysm was treated by stent-assisted coil embolization.
Conclusion
We successfully treated 15 wide-necked intracranial aneurysms by the endovascular method. More clinical data with longer follow-up periods are needed to establish the use of endovascular treatment for wide-necked aneurysm.
doi:10.3340/jkns.2011.49.2.97
PMCID: PMC3079106  PMID: 21519497
Intracranial aneurysm; Embolization; Stent
5.  Endovascular Treatment for Very Small Supraclinoid Aneurysms with Stent-Assisted Coiling 
Interventional Neuroradiology  2009;15(1):37-44.
Summary
The endovascular treatment of very small aneurysms (lesions less than 3 mm in maximum diameter) with wide necks remains a challenge for saccular embolization. We retrospectively analyzed our data using Neuroform stent-assisted coiling for very small supraclinoid aneurysms with wide neck to evaluate the feasibility and efficacy of endovascular treatment of these lesions.
We conducted a review of our experience and results of endovascular treatments in six patients with seven very small aneurysms. All aneurysms were located at the side wall of the supraclinoid segment of the ICA. They were ruptured in two patients and unruptured in four. The technique of stent-assisted coiling was used in all cases with coiling before stenting and additional coils after deployment of the stent in the same session.
All patients were successfully embolized with stent-assisted coiling. The coils were introduced into the lumen for subtotal occlusion in five aneurysms and for partial occlusion in two. During one to two years follow-up angiography, all aneurysms were completely occluded and no recurrence occurred. No complications were observed.
Endovascular stent-assisted coil embolization of supraclinoid very small aneurysms with wide necks is effective and feasible. Subtotal aneurysm occlusion might progress to total occlusion.
PMCID: PMC3306147  PMID: 20465927
supraclinoid aneurysm, very small, stent assisted coiling, follow-up
6.  Initial Experience with the Coaxial Dual-Lumen Ascent Balloon Catheter for Wide-Neck Aneurysm Coil Embolization 
Introduction: Techniques for coil embolization of wide-neck cerebral aneurysms include the use of stents and temporary occlusion with compliant non-detachable balloons to safely allow dense packing of the aneurysm lumen with detachable coils. We describe the use of a new balloon device for assisting in wide-neck aneurysm coil treatment. Methods: A single institution neuroendovascular database was accessed to identify cases in which the Ascent balloon (Codman Neurovascular, Raynham, MA, USA) was used for aneurysm coil embolization. Clinical, demographic, and angiographic data were obtained through chart review. Results: Eleven cerebral aneurysm cases were treated using the Ascent balloon during the first 12-month period that the new device was available at our institution. Three of the patients presented with ruptured aneurysms. All aneurysms were large (maximum diameter 6 mm or greater), with an average maximum diameter of 9.4 mm, and an average neck diameter of 5.5 mm. Complete occlusion with coil embolization (Raymond class I) was achieved in all cases. The Ascent balloon was successfully positioned across the neck of the aneurysm in nine patients. Conclusion: This initial experience demonstrates the feasibility and immediate outcomes of the coaxial dual-lumen design Ascent balloon catheter used as an assistive device in coil embolization of wide-neck cerebral aneurysms. This device contributes to the growing number of assistive devices for the treatment of complex cerebral aneurysms.
doi:10.3389/fneur.2011.00052
PMCID: PMC3158366  PMID: 21897828
aneurysm embolization; ascent; balloon remodeling; coil
7.  Endovascular Treatment of Wide-Necked Intracranial Aneurysms Using Balloon-Assisted Technique with HyperForm Balloon 
Objective
To assess the feasibility, safety, and effectiveness of the balloon-assisted technique with HyperForm balloon in the endovascular treatment of wide-necked intracranial aneurysms.
Methods
A total of 34 patients with 34 wide-necked intracranial aneurysms were treated with endovascular coil embolization using balloon-assisted technique with Hyperform balloon. Twenty-nine aneurysms (85.3%) were located in the anterior circulation. The group of patients was comprised of 16 men and 18 women, aged 33 to 72 years (mean : 60.6 years). The size of aneurysms was in the range of 2.0 to 22.0 mm (mean 5.5 mm) and one of neck was 2.0 to 11.9 mm (mean 3.8 mm). The dome to neck ratio was ranged from 0.83 to 1.43 (1.15). Sixteen patients were treated for unruptured aneurysms and the remaining 18 presented with a subarachnoid hemorrhage.
Results
In the 34 aneurysms treated by the remodeling technique with HyperForm balloon, immediate angiographic results consisted of total occlusion in 31 cases (91.2%) and partial occlusion in three cases (8.8%). There were five procedure-related complications (14.7%), including two coil protrusions and three thromboembolisms; Except one patient, all were successfully resolved without permanent neurologic deficit. No new bleeding occurred during the follow-up. Twenty patients (59%) underwent angiographic follow-up from 2 to 33 months (mean 9.2 months) after treatment. Focal recanalization with coil compaction of the neck portion was observed in 5 cases (25%). Only one case showed major recanalization and underwent stent-assisted coil embolization.
Conclusion
The balloon-assisted technique with Hyperform balloon is a feasible, safe, and effective endovascular treatment of wide-necked cerebral aneurysms.
doi:10.3340/jkns.2010.48.3.207
PMCID: PMC2966720  PMID: 21082046
Intracranial aneurysms; Wide-necked aneurysms; Endovascular treatment; Balloon-assisted technique
8.  Stent-Assisted Coil Embolization of Complex Wide-Necked Bifurcation Cerebral Aneurysms Using the “Waffle Cone” Technique 
Interventional Neuroradiology  2012;18(1):20-28.
Summary
Endovascular treatment of complex, wide-necked bifurcation cerebral aneurysms is challenging.  Intra/extra-aneurysmal stent placement, the “waffle cone” technique, has the advantage of using a single stent to prevent coil herniation without the need to deliver the stent to the efferent vessel. The published data on the use of this technique is limited. We present our initial and follow-up experience with the waffle cone stent-assisted coiling (SAC) of aneurysms to evaluate the durability of the technique. We retrospectively identified ten consecutive patients who underwent SAC of an aneurysm using the waffle cone technique from July 2009 to March 2011. Clinical and angiographic outcomes after initial treatment and follow-up were evaluated.
Raymond Class I or II occlusion of the aneurysm was achieved in all cases with the waffle cone technique. No intraoperative aneurysm rupture was noted. The parent arteries were patent at procedure completion. Clinical follow-up in nine patients (median 12.9 months) revealed no aneurysm rupture. Two patients had a transient embolic ischemic attack at 18 hours and three months after treatment, respectively. Catheter angiography or MRA at six-month follow-up demonstrated persistent occlusions of aneurysms in seven out of eight patients. Another patient had stable aneurysm occlusion at three-month follow-up study. Our experience in the small series suggests the waffle cone technique could be performed on complex, wide-necked aneurysms with relative safety, and it allowed satisfactory occlusions of the aneurysms at six months in most cases.
PMCID: PMC3312085  PMID: 22440597
waffle cone technique, wide-necked aneurysm, stent-assisted, coiling, endovascular
9.  Simple coiling using single or multiple catheters without balloons or stents in middle cerebral artery bifurcation aneurysms 
Neuroradiology  2012;55(3):321-326.
Introduction
We evaluated the outcomes of middle cerebral artery bifurcation (MCAB) aneurysms treated with simple coiling using single or multiple catheters without stents or balloons.
Methods
This study included 100 patients with 103 MCAB aneurysms who underwent a simple coiling procedure without the adjuvant use of stents or balloons. The angiographic clinical outcomes and recurrence of these aneurysms were evaluated.
Results
Of the 103 aneurysms, 102 (99.0 %) aneurysms were successfully treated with simple coiling. One patient died from the consequences of a procedural aneurysm rupture. The treatment-associated permanent morbidity and mortality rates were 0 and 1.0 %, respectively. Post-coiling angiograms showed 28 complete occlusions (27.2 %), 60 neck remnants (58.3 %), and 14 partial occlusions (13.6 %). A follow-up angiography (median duration, 30 months; range, 3–73 months) was performed in 80 lesions. Recanalisation was found in 28 lesions (35.0 %), of which 6 were complete occlusions, 18 were neck remnants, and 4 were partial occlusions, as determined by post-coiling angiograms. Among these lesions, 14 major recurrences were retreated with coiling (n = 12) and clipping (n = 2) without complications. Age (odds ratio [OR], 0.93; 95 % confidence interval [CI], −0.11 to −0.01; p = 0.03), the presence of a rupture (OR, 3.89; 95 % CI, 0.12 to 2.60; p = 0.03), and a wide aneurysm neck (OR, 6.40; 95 % CI, 0.57 to 3.14; p = 0.005) were significantly associated with the aneurysm recurrence, as determined by multivariable analyses.
Conclusion
Our study suggests that simple coiling of MCAB aneurysms is feasible and safe; however, it has limitations in durability, particularly in ruptured or wide-necked aneurysms and in young patients.
doi:10.1007/s00234-012-1119-4
PMCID: PMC3582817  PMID: 23192399
Aneurysm; Coiling; Simple; Middle cerebral artery; Endovascular
10.  Initial Experience with Neuroform EZ in the Treatment of Wide-neck Cerebral Aneurysms 
Neurointervention  2012;7(1):34-39.
Purpose
Stent-assisted coiling allows embolization and parent vessel reconstruction of wide-necked intracranial aneurysms. The Neuroform EZ (Boston Scientific, Fremont, CA, U.S.A.) stent delivery system offers deployment of a Neuroform stent with fewer steps and improved operator control. Initial experience, technical considerations, and treatment outcomes using the Neuroform EZ stent delivery system in combination with coil embolization are reported.
Materials and Methods
Seventeen consecutive patients harboring 21 wide-necked saccular cerebral aneurysms were treated with stent reconstruction. Twenty aneurysms were unruptured; one was treated within 24 hours of diagnosis of rupture. Twenty aneurysms were located in the anterior circulation; one was in the posterior circulation. Immediate and six-month post-treatment angiography and clinical assessment were performed.
Results
In all cases, the stents were delivered and positioned without difficulty in deployment. Technical complications occurred in 4 patients, but none were directly related to the stent delivery system. On immediate post-treatment angiography, 5 of 21 aneurysms showed complete occlusion, 5 of 21 showed residual neck, and 11 of 21 showed residual contrast filling of the aneurysm sac. At six month follow-up, all 17 patients were clinically stable. Angiography of 18 of the aneurysms showed total occlusion in 12, residual neck in 3, and residual aneurysm filling in 3. Retreatment was performed in the three with residual aneurysm.
Conclusion
The Neuroform EZ stent system offers improved anchoring and support in stent delivery, which is particularly useful when multiple stents are overlapped to further protect the parent vessel and increase flow diversion away from the aneurysm sac. The only significant problem encountered was coil prolapse, which could be treated with a second stent when necessary. The ease of deployment improves upon the already clinically successful Neuroform design.
doi:10.5469/neuroint.2012.7.1.34
PMCID: PMC3299948  PMID: 22454783
Aneurysm; Coil embolization; Neuroform EZ; Stent-assisted coiling
11.  Stent-assisted coiling in ruptured wide-necked aneurysms: A single-center analysis 
Background:
To evaluate the safety and efficacy of stent-assisted coiling of ruptured intracranial wide-necked aneurysms in a setting of acute subarachnoid hemorrhage, without compromising on the antiplatelet regimen.
Methods:
Forty-two consecutive patients who underwent stent-assisted coiling for ruptured wide-necked intracranial aneurysms from August 2008 to May 2012 were studied. Demographic data like age, sex, Hunt & Hess grade, Fischer scale, and location, and size of the aneurysms were noted. Complications such as aneurysmal rupture, bleeding complications, thromboembolic events, etc. were documented. Also, 30-day and 1-year outcome was measured using modified Rankin scale (mRS).
Results:
Forty-four wide-necked aneurysms were treated in 42 patients with stent-assisted coiling from August 2008 to May 2012 in our institution, out of a total of 248 aneurysms treated endovascularly in the same period. All these patients presented with subarachnoid hemorrhage (SAH) with varying grades and were treated in the acute phase, i.e. within 1 week of the ictus. There were 24 males and 18 females in the age group ranging from 12 to 78 years, with a mean of 45 years. Technical success was achieved in 39 patients with complete angiographic cure (93%). Intraprocedural stent thrombosis was seen in two patients, which resolved with intra-arterial bolus of tirofiban, and both the patients did not have any neurological deficit. Rebleed occurred in two patients of which one patient succumbed.
Six patients required external ventricular drain because of worsening hydrocephalus on computed tomography (CT) scan with clinical deterioration. There was one death in our series due to rebleed. Three other patients died in a period of 1 month due to complications not related to the coiling procedure which include vasospasm, pulmonary embolism, and respiratory infection. All the patients were clinically followed up at 1 month, 3 months, 6 months, and 1 year. Also, angiographic follow- up was done at 1 year in 25 patients (72%). All the patients were maintained on clopidogrel 75 mg per day and ecospirin 150 mg per day for a period of 1 year and were advised to continue ecospirin 150 mg per day lifelong.
Conclusion:
Even in a setting of acute SAH, stent-assisted coiling can be an effective and safe treatment option with acceptable risks in experienced hands.
doi:10.4103/2152-7806.102946
PMCID: PMC3513848  PMID: 23227436
Stent-assisted coiling; subarachnoid hemorrhage; wide-necked aneurysm
12.  Enterprise Stent-Assisted Coiling of Wide-Necked Intracranial Aneurysms: Clinical and Angiographic Follow-up 
Jia, J. | Lv, X. | Liu, A. | Wu, Z. | Li, Y.
Interventional Neuroradiology  2012;18(4):426-431.
Summary
We evaluate and report our clinical and angiographic outcomes associated with stent-assisted coil embolization of wide-necked intracranial aneurysms using the Enterprise stent.
One hundred sixty-nine patients diagnosed with 182 wide-necked intracranial aneurysms underwent placement of the Enterprise stent between April 2009 and October 2011. Demographic information, procedural data, procedure-related complications, angiographic results, and clinical outcomes were reviewed and evaluated.
Stent deployment was successful in 166 out of 169 procedures (98.2%). Four patients had acute procedure-related complications, including thromboembolism in three patients and aneurysm perforation resulting in the death of one patient. Immediate angiographic results showed complete occlusion in 101 aneurysms (56.4%) and near-complete occlusion in 55 aneurysms (30.7%). Follow-up angiography was performed in 108 patients with 119 aneurysms at a mean of 8.1 months: complete occlusion was observed in 95 aneurysms (79.8%) and near-complete occlusion was found in 12 aneurysms (10.1%). Delayed intra-stent thromboses were observed in two patients, and asymptomatic in-stent stenosis was observed in one patient. Ten aneurysms (8.4%, 10/119) demonstrated recanalization, all of which were subsequently recoiled successfully. Clinical follow-up was obtained for 132 patients at a mean of 11.4 months, out of which 118 (89.4%) had favorable clinical outcomes as determined using a modified Rankin Scale (mRS) ≤1. The rates of procedure-related mortality and permanent morbidity were 0.6% (1/169) and 2.3% (3/132), respectively.
This study adds to the current body of evidence supporting the Enterprise stent as an effective and safe tool for the treatment of wide-necked intracranial aneurysms because it results in more complete occlusion and lower complication rates.
PMCID: PMC3520556  PMID: 23217637
Enterprise stent, stent-assisted coiling, wide-necked intracranial aneurysms
13.  Enterprise stent for waffle-cone stent-assisted coil embolization of large wide-necked arterial bifurcation aneurysms 
Background:
Large wide-necked arterial bifurcation aneurysms present a unique challenge for endovascular coil embolization treatment. One technique described in the literature deploys a Neuroform stent into the neck of the aneurysm in the shape of a waffle-cone, thereby acting as a scaffold for the coil mass. This case series presents four patients with large wide-necked bifurcation aneurysms treated with the closed-cell Enterprise stent using the waffle-cone technique.
Case Description:
Four patients (59 ± 18 years of age) with large wide-necked arterial bifurcation aneurysms (three basilar apex and one MCA bifurcation) were treated with the waffle-cone technique using the Enterprise stent as a supporting device for stent-assisted coil embolization. Three of the patients presented with aneurysmal subarachnoid hemorrhage (Hunt-Hess 2-3; Fisher Grade 3-4). There was no procedural morbidity or mortality associated with treatment itself. One aneurysm was completely obliterated, and three had small residual necks. One patient developed an area of PCA infarct and visual field cut one month after the procedure and required recoiling of the residual neck. The flared ends of the Enterprise stent remodeled the aneurysm neck by conforming to the shape of the neck without any technical difficulty, resulting in a stable scaffold holding the coils into the aneurysm.
Conclusion:
The closed cell construction, flexibility, and flared ends of the Enterprise stent allow it to conform to the waffle-cone configuration and provide a stable scaffold for coil embolization of large wide-necked arterial bifurcation aneurysms. We have had excellent initial results using the Enterprise stent with the waffle-cone technique. However, this technique is higher risk than standard treatment methods and therefore should be reserved for large wide-necked bifurcation aneurysms where Y stenting is needed, but not possible, and surgical clip ligation is not an option.
doi:10.4103/2152-7806.106268
PMCID: PMC3589841  PMID: 23493649
Aneurysm; coil; embolization; enterprise; stent; waffle-cone; wide-necked
14.  Various Techniques of Stent-Assisted Coil Embolization of Wide-Necked or Fusiform Middle Cerebral Artery Aneurysms : Initial and Mid-Term Results 
Objective
To evaluate the feasibility and clinical and angiographic outcomes of stent-assisted embolization for complex middle cerebral artery (MCA) aneurysms.
Methods
The records of 23 consecutive patients with 24 MCA aneurysms, who underwent stent-assisted embolization of the aneurysm, were retrospectively evaluated.
Results
Fifteen aneurysms were treated with one stent and 8 were treated using more than two stents (5 a stent-within-a-stent, 1 triple stents, and two Y-stent). Angiographically, complete or near complete occlusion was achieved in 15 aneurysms (65.2%), residual neck in five (21.7%), and residual aneurysm in three (13.1%). Five aneurysms demonstrated thrombosis within the stent during the procedure and hospitalization, and were resolved by intraarterial and intravenous Tirofiban injection. Symptomatic thromboembolic complications were developed in five patients and permanent deficits demonstrated in two patients with modified Rankin Scale 1 and 2, respectively. Treatment-related permanent morbidity and mortality rates were 8.3% and 0% with relatively high complication rate. Angiographic follow-up was available in 17 aneurysms at 6-31 months (mean, 13.2 months) and showed stable or improved in 15 (88.2%) and major and minor recurrence in one, respectively.
Conclusion
Complex MCA aneurysms could be treated by stent-assisted coiling and showed lower recanalization rate during mid-term follow-up by effective flow diversion due to various stent-assisted techniques. Our results warrant further study with a longer follow-up period in a larger sample.
doi:10.3340/jkns.2013.53.5.274
PMCID: PMC3730028  PMID: 23908700
Coil embolization; Intracranial aneurysm; Middle cerebral artery; Stent
15.  Leo Stent for Endovascular Treatment of Broad-Necked and Fusiform Intracranial Aneurysms 
Interventional Neuroradiology  2007;13(3):255-269.
Summary
The advent of intracranial stents has widened the indications for endovascular treatment of broad-necked and fusiform aneurysms. Leo stent is a self-expandable, nitinol, braided stent dedicated to intracranial vessels. The aim of this study is to present our experience in endovascular treatment of broad-necked and fusiform intracranial aneurysms using self-expanding, nitinol Leo stents.
Between February 2004 and November 2006, 25 broad-necked and three fusiform aneurysms in 28 patients were treated using Leo stents in our centre. There were 18 patients who experienced acute subarachnoid haemorrhage due to aneurysm rupture, two patients who experienced SAH at least 12 months ago and in eight patients aneurysms were found incidentally. Aneurysms were located as follows: internal carotid artery15, basilar artery5, basilar tip3, posterior inferior cerebral artery2, M1/M2 segment1, A2 segment1 and vertebral artery1.
There were no difficulties with stent deployment and delivery. All patients after acute SAH (n=18) underwent stent implantation and coil embolization in one procedure. The remaining patients underwent coil embolization in a staged procedure. Immediate aneurysm occlusion of more than 95% was achieved in all patients who underwent stent placement and coil embolization in one procedure. There were three thromboembolic complications encountered in patients in an acute setting of SAH, preloaded only on acetylsalicylic acid. Use of abciximab led to patency within the stent and parent vessel. However, one of these patients presented rebleeding from the aneurysm during administration of abciximab and died.
Application of Leo stents in cases of broadnecked and fusiform intracranial aneurysms is safe and effective with a low complication rate.
PMCID: PMC3345341  PMID: 20566117
endovascular, intracranial aneurysm, Leo, stent, fusiform
16.  Temporary Semi-Jailing Technique for Coil Embolization of Wide-Neck Aneurysm with Small Caliber Parent Artery Following Incomplete Clipping 
The authors describe the use of a self-expandable stent in a temporary deployment for treatment of a very wide-neck A1 segment of anterior cerebral artery (ACA) aneurysm following incomplete clipping. A 39-year-old hypertensive man presenting with seizure-like movement underwent computed tomography, which showed acute subarachnoid hemorrhage and an A1 segment of ACA aneurysm with superior and inferior projection. He underwent surgical clipping of the aneurysm, but superior and posterior portion of wide-neck aneurysm remained. We decided to treat the remnant aneurysm using an endovascular modality. After selection of the aneurysm, coil packing was performed assisted by the temporary semi-jailing technique. The Enterprise stent (Cordis Neurovascular, Miami, FL, USA) was deployed and recaptured repeatedly for angiography to ensure safety of the small caliber parent artery. Successful semi-deployment and recapture of the stent allowed subtotal coil occlusion of the aneurysm with good anatomic and clinical results. No complications were encountered. The stent could be recaptured up to the point where the proximal end of the stent marker was aligned with distal marker band of the microcatheter, approximately 70% of the stent length. The temporary semi-jailing technique is feasible for wide-neck aneurysm with small caliber parent artery.
doi:10.3340/jkns.2013.53.4.241
PMCID: PMC3698235  PMID: 23826481
Intracranial aneurysm; Endovascular therapy; Stent; Surgical clipping
17.  Additional Rescue Stent Placement for Stabilization of a Prolapsed Coil during Stent-assisted Coil Embolization of a Wide-Neck Intracranial Aneurysm 
Interventional Neuroradiology  2006;12(3):257-262.
Summary
We report a case of a 55-year-old man carrying two unruptured internal carotid artery (ICA) wide-neck aneurysms.
In the same session, the smaller aneurysm was treated by coils using the remodeling technique and the large aneurysm was treated by stent-assisted coil embolization. During the stent-assisted procedure for the large aneurysm, the microcatheter tip moved from the aneurysm into the parent artery causing a prolapse of some coil loops into the vessel lumen.
The distal part of the coil was tangled within the stent's struts, therefore, in order to introduce the entire coil, an attempt was made to withdraw the prolapsed loops of the coil within the microcatheter and concomitantly repositioning the microcatheter into the residual aneurysm neck through the stent struts. However this maneuver was unsuccessful.
An attempt to retrieve gently the coil also failed and the coil prematurely detached. For maintaining the patency of the arterial lumen and to reduce the embolic risk, a second stent was used to pin the free coil loops. The rescue stent was positioned within the coil loops and its deployment allowed a circumferential expansion of some loops around the stent perimeter while other loops were flattened against the wall of the artery. The parent artery remained patent at one-year follow-up angiographic study. No clinical complications were observed.
PMCID: PMC3354544  PMID: 20569580
aneurysms, wide-neck, coils, stents
18.  Experiences of Neuroform Stent Applications for Ruptured Anterior Communicating Artery Aneurysms with Small Parent Vessel 
Objective
The purpose of this study was to review the safety and durability of aneurysms treated with stent-assisted coiling of ruptured anterior communicating artery aneurysms with small parent vessels (< 2.0 mm).
Methods
Retrospective review of all ruptured aneurysm treated with stent assisted endovascular coiling between March 2005 and March 2009 at our institution was conducted. We report 11 cases of the Neuroform stent placement into cerebral vessels measuring less than 2.0 mm in diameter (range, 1.3-1.9 mm) in anterior cerebral artery. Clinical follow-up ranged from 3 to 12 months and imaging follow-up was performed with cerebral angiography at 6 months and 12 months after discharge.
Results
Complete occlusion was achieved in 10 patients, and a remnant neck was evident in one. No stent displacement or no dislodgement occurred during stent placement. There was no evidence of thromboembolic complication, arterial dissection and spasm during procedure. We performed follow-up angiography in all patients at 6 months and/or 12 months from the first procedure. The follow-up angiographic data showed successfully results except one in-stent stenosis case. All patients improved clinical performances except one patient with severe vasospasm who showed poor clinical condition initially.
Conclusion
We have safely and successfully treated 11 vessels smaller than 2.0 mm in diameter with self-expanding stents with good short and intermediate term results. More clinical data with longer follow-ups are needed to establish the role of stent-assisted coiling in ruptured aneurysms with small parent vessels.
doi:10.3340/jkns.2010.48.1.53
PMCID: PMC2916148  PMID: 20717512
Neuroform stent; Small parent vessel
19.  Comparison of Devices Used for Stent-Assisted Coiling of Intracranial Aneurysms 
PLoS ONE  2011;6(9):e24875.
Introduction
Two self-expandable stents, the Neuroform and the Enterprise stent, are widely used for stent-assisted coiling (SAC) of complex shaped intracranial aneurysms. However, comparative knowledge about technical feasibility, peri- and post-procedural morbidity and mortality, packing densities as well as follow-up data is limited.
Material and Methods
We conducted a retrospective study to investigate differences in aneurysms stented with the Enterprise or Neuroform stents. Angiographic follow-up (mean 19.42 months) was available in 72.6% (61/84) of aneurysms treated with stent-assisted coiling. We further sought to compare stent-assisted coiling to a matched patient population with aneurysms treated by conventional coil embolization.
Results
The stenting success rate of the Enterprise was higher compared to the Neuroform stent (46/48 and 42/51, respectively). In 5 of 9 cases in which the Neuroform stent was not navigable to the landing zone, we successfully deployed an Enterprise stent instead. Eventually, 42 aneurysms were coiled after stenting in each group. We observed no significant differences in peri-procedural complication rate, post-procedural hospital stay, packing density, recurrence rate or number of in-stent stenosis. Strikingly, 36.1% of followed aneurysms in the SAC group showed progressive occlusion on angiographic follow-up imaging. The packing density was significantly higher in aneurysms treated by SAC as compared to conventionally coiled aneurysms, while recanalization rate was significantly lower in the SAC group.
Conclusion
The procedural success rate is higher using the Enterprise, but otherwise both stents exhibited similar characteristics. Lower recurrence frequency and complication rates comparable to conventional coil embolization emphasize the importance of stent-assisted coiling in the treatment of complex aneurysms. Progressive occlusion on angiographic follow-up was a distinct and frequent observation in the SAC group and may in part be due to flow diversion.
doi:10.1371/journal.pone.0024875
PMCID: PMC3178562  PMID: 21966374
20.  Y-Stent-Assisted Coil Embolization of Wide-Neck Intracranial Aneurysms 
Interventional Neuroradiology  2011;17(1):36-48.
Summary
This report evaluated the short and midterm results of the safety and effectiveness of the treatment technique with hybrid and non-hybrid Y-configured, dual stent-assisted coil embolization of wide-neck intracranial aneurysms, and reviewed the literature concerning this technique.
Nine patients, eight with unruptured and one with ruptured aneurysms were included in the study. Of aneurysms embolized with a hybrid (with two different stents) and non-hybrid (with two identical stents) technique, three were located in the anterior communicating artery, three at the tip and one at the distal site of basilar artery, and two in the middle cerebral artery. All aneurysms included the orifices of bifurcation vessels. All aneurysms were stented and embolized during the same session. While Neuroform and Enterprise stents were used in the hybrid technique, two Enterprise stents were used in the non-hybrid technique.
Dual Y-stent assisted coil embolization was performed successfully in eight of nine patients (88.9%), including five patients (55.6%) with hybrid and three patients (33.3%) with non-hybrid technique. No procedural complication, no mortality and no minor or major neurological complications were seen during the angiographic or clinical follow-up. When an attempt was made at passing the second stent through the first Enterprise stent, the stent protruded inside the aneurysm in one patient (11.1%).
Hybrid or non-hybrid dual Y-stent-assisted coil embolization in the treatment of ruptured or unruptured wide-neck and complex intracranial aneurysms is a safe and effective method from the viewpoint of short and midterm results.
PMCID: PMC3278021  PMID: 21561557
intracranial aneurysm, stent, therapeutic embolization
21.  Thromboembolic Events Associated with Coil Protrusion into Parent Arteries after GDC Treatment 
Interventional Neuroradiology  2006;12(Suppl 1):105-111.
Summary
Aneurysm embolization using Guglielmi detachable coils(GDC) is gaining acceptance as a viable alternative to surgery in the treatment of cerebral aneurysms. During GDC treatment of cerebral aneurysms, thromboembolic events are the most frequent complications. As risk factors of thromboembolic events, large aneurysms, wide-necked aneurysms, use of the balloon-assisted technique and protruding coils into the parent arteries are previously reported. From March, 1997 till August, 2004, 270 consecutive patients were treated with GDC embolization at our institute. Fourteen (5.2%) patients with 14 aneurysms of these 270 patients presented with protruding coils into the parent vessels.
Twelve aneurysms of these 14 aneurysms were small (diameter <10 mm), and two were large (diameter 15 mm). Nine aneurysms had small necks (neck diameter <4 mm), and five had wide necks (neck diameter >4 mm). The fundus-to-neck ratio ranged from 1.04 to 2.78, with an average of 1.53.
In this series, ten patients (71%) were treated with balloon-remodelling technique because every patient had either a wide-necked aneurysm or complicated morphologic factors. These 14 aneurysms were divided into two groups according to the mode of coil protrusion, loop type and tail type protrusion. The first coil was protruded in five (36%) cases of 14 patients, four of these five cases presented with the loop type protrusion. The last coil was protruded in seven cases (50%), Five of these seven cases presented with the tail type protrusion. Diffusion-weighted imaging abnormalities were found for seven (50%) of 14 patients within 24 hours of the coiling procedures. Three (21%) of 14 patients showed small lesions (<5 mm) in the subcortical white matter at the border zone or perforating regions. In four (29%) patients, large territorial infarctions (> 5 mm) were detected. Symptomatic complications occurred in four (29%) patients, and all of these four patients presented the loop type protrusion. One patient who had small infarctions experienced minimal deficits (slight motor weakness, quadrantic hemianopsia) after six days postprocedure and fully recovered by discharge after stronger systemic heparinization (24000U, for three days), aspirin (100 mg/day) and Ticlopidine (100 mg/day). Three patients who had large territorial infarctions experienced moderate deficits.
Two patients were treated with stronger systemic heparinization and one with Argatroban (60 mg/day, for two days), and following aspirin (100 mg/day) and Ticlopidine (100 mg/day). Finally, two patiens were discharged with permanent minimal deficits (hypoesthesia only) and one with moderate hemiparesis. The infarctions related to the GDC procedures were more common sequelae in wide-necked aneurysms and coil protrusions, especially loop type protrusion. Although permanent neurological deficits were rare, the high rate of thromboembolic events associated with coil protrusion suggest that more aggressive medical treatment should be considered.
PMCID: PMC3387935  PMID: 20569612
coil protrusion, thromboembolic events, DW imaging
22.  Waffle-Cone Technique Using Solitaire AB Stent 
The waffle-cone technique is a modified stent application technique, which involves protrusion of the distal portion of a stent into an aneurysm fundus to provide neck support for subsequent coiling. The authors report two cases of wide necked basilar bifurcation aneurysms, which were not amenable to stent assisted coiling, that were treated using the waffle-cone technique with a Solitaire AB stent. A 58-year-old woman presented with severe headache. Brain CT showed subarachnoid hemorrhage and angiography demonstrated a ruptured giant basilar bifurcation aneurysm with broad neck, which was treated with a Solitaire AB stent and coils using the waffle-cone technique. The second case involved an 81-year-old man, who presented with dizziness caused by brain stem infarction. Angiography also demonstrated a large basilar bifurcation unruptured aneurysm with broad neck. Solitaire AB stent deployment using the waffle-cone technique, followed by coiling resulted in near complete obliteration of aneurysm. The waffle-cone technique with a Solitaire AB stent can be a useful alternative to conventional stent application when it is difficult to catheterize bilateral posterior cerebral arteries in patients with a wide-necked basilar bifurcation aneurysm.
doi:10.3340/jkns.2012.51.4.222
PMCID: PMC3377880  PMID: 22737303
Wide-necked aneurysm; Waffle-cone technique; Solitaire AB stent
23.  Peri-Procedural Morbidity and Mortality Associated with Stent-Assisted Coiling for Intracranial Aneurysms 
Interventional Neuroradiology  2013;19(1):43-48.
Summary
Despite experience and technological improvements, stent-assisted coiling for intracranial aneurysms still has inherent risks. We evaluated peri-procedural morbidity and mortality associated with stent-assisted coiling for intracranial aneurysms.
Patients with cerebral aneurysms that were broad-based (>4 mm) or had unfavorable dome/neck ratios (<1.5) were enrolled in this study between February and November 2011 at our center. Aneurysms were treated with the self-expanding neurovascular stents with adjunctive coil embolization.
Seventy-two consecutive patients (27 men and 45 women; 22-78 years of age; mean age, 52.8 years) underwent 13 procedures for 13 ruptured aneurysms and 64 procedures for 73 unruptured aneurysms. Nine [11.7%, 95%CI(4.5%-18.9%)] procedure-related complications occurred: one and eight with initial embolization of ruptured and unruptured aneurysms, respectively. Complications included six acute in-stent thromboses, one spontaneous stent migration, one post-procedural aneurysm rupture, and one perforator occlusion. Three complications had no neurologic consequences. Two caused transient neurologic morbidity, two persistent neurologic morbidity, and two death. Procedure-related neurologic morbidity and mortality rates, respectively, were as follows: overall, 5.2% (95%CI, 0.2%-10.2%) and 2.6% (95%CI, 0%-6.2%); ruptured aneurysms, 7.7% (95%CI, 0%-36%) and 0%(95%CI, 0%-25%); unruptured aneurysms, 4.7% (95%CI, 0%-9.9%) and 3.1% (95%CI, 0%-7.3%). Combined procedure-related morbidity and mortality rates for ruptured and unruptured aneurysms were 7.7% (95%CI, 1.7%-13.7%) and 7.8% (95%CI, 1.8%-13.8%), respectively.
Stent-assisted coiling is an attractive option for intracranial aneurysms. However, stent-assisted coiling for unruptured aneurysms is controversial for its comparable risk to natural history.
PMCID: PMC3601616  PMID: 23472722
broad-based aneurysm, intracranial aneurysms, stent-assisted coiling, stents
24.  Use of stent-assisted coil embolization for the treatment of wide-necked aneurysms: A systematic review 
Background:
The use of stent-assisted coiling (SAC) has been shown to be a treatment option for complex aneurysms. We reviewed systematically the immediate and mid-term angiographic results following treatment of wide-necked aneurysms with self-expanding stents and coils, as well as the peri- and postprocedural rate of complications.
Methods:
A computerized database search was conducted from 01/2000 to 04/2011 using appropriate indexed terms on Pubmed. Inclusion criteria were: (1) homogeneous populations of ≥10 patients with wide-necked aneurysms; (2) use of a self-expandable neurovascular stent and coils for aneurysm treatment; (3) immediate and follow-up angiographic results; and (4) periprocedural and delayed thrombotic complications.
Results:
Seventeen studies were included, containing retrospectively collected data on 656 patients/702 aneurysms. The target aneurysm was located on the anterior circulation in 78.4% of patients. The immediate rate of complete occlusion was 46.3%, (19.3-98.1%). The intra- and postprocedural rate of intrastent thrombosis or thromboembolic event was 4.6% and 4.3%, respectively. Complete occlusion was documented in 71.9% at last angiographic follow-up. The rate of recanalization was 13.2% of aneurysms (0-28.8%). Delayed in-stent stenosis occurred in 5.3% cases (0-20.6%).
Conclusion:
SAC has been considered a treatment option for selected wide-necked aneurysms in some institutions. The use of intracranial stents should take into consideration the risk of ischemic complications, recanalization, delayed in-stent stenosis; and the currently unknown lifetime risks for stenosis, vascular injury, device failure, and aneurysm recurrence related to intracranial stenting. There is an evident need for a prospective multicenter registry for all treated patients with SAC.
doi:10.4103/2152-7806.109810
PMCID: PMC3622357  PMID: 23607065
Aneurysm occlusion; complication; intracranial aneurysm; intracranial stent; wide neck aneurysm
25.  Stent-Assisted Coil Embolization of Wide-Necked Intracranial Aneurysms Using a Semi-Deployment Technique: Angiographic and Clinical Outcomes in 31 Consecutive Patients 
Interventional Neuroradiology  2010;16(4):385-393.
Summary
We describe a modified stent-assisted coiling technique, named the semi-deployment technique, in the endovascular treatment of wide-neck aneurysms. Thirty-one consecutive patients with 31 wide-necked or fusiform intracranial aneurysms were treated with the semi-deployment technique. The technical feasibility of the procedure, procedure-related complications, angiographic results, clinical outcome and follow-up angiography were evaluated. In every case, the semi-deployment technique was successfully deployed. Immediate angiography demonstrated complete occlusion in 24 cases (77.4%), neck remnant in four cases (12.9%), and incomplete occlusion in three cases (9.7%). Procedural-related morbidity occurred in one patient (3.2%) but no procedural-related mortality. A favorable clinical outcome (Modified Ran-kin Scale score 0-2) was observed in 90.3% of the patients (average follow-up time, 23.1 months). No rehemorrhage of treated aneurysms occurred. Angiography follow-up was obtained in 22 cases (71.0 %). Three aneurysms (13.6 % of the follow-up angiograms) demonstrated recanalization. No delayed coil or stent migration was found. One patient had in-stent stenosis as a delayed complication. We found that the semi-deployment technique was helpful in the treatment of wide-neck aneurysms.
PMCID: PMC3278013  PMID: 21162768
intracranial aneurysm, stent, endovascular embolization, therapeutic

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