Flow Diversion for Intracranial Aneurysms

Flow Diverters in the Treatment of Pediatric Cerebrovascular Diseases

BACKGROUND AND PURPOSE

There is very limited data concerning utilization of flow diverters in children. Our aim is to report results for the treatment of complex intracranial aneurysms and carotid cavernous fistulas by using flow diverters in children.

MATERIALS AND METHODS

Retrospective review of children (17 years of age or younger) treated with flow diverters between May 2011 and July 2014 was performed. Clinical and laboratory data and angiographic findings were extracted. Seven patients (6 males, 1 female; mean age, 12.7 years; range, 3-16 years) were included. Two presented with posttraumatic fistulas. The remaining patients presented with traumatic aneurysms of the cavernous carotid artery or fusiform aneurysms of the distal vertebral artery, M1, or A2 segments. All patients were premedicated with clopidogrel (75 mg daily for patients with body weights of >45 kg, 37.5 mg daily for 1 small child with a body weight of <45 kg) and aspirin (300 mg daily for ≥45 kg, 100 mg daily for smaller children).

RESULTS

VerifyNow and Multiplate Analyzer values were higher than expected. No clinical complications were noted. Imaging performed at 7-52 months after the procedure (mean/median, 22.3/14 months) revealed occlusions of all aneurysms and fistulas. One patient had an asymptomatic occlusion of the parent artery; otherwise, no hemodynamically significant parent artery restenosis was observed. There were no clinically significant neurologic events during follow-up.

CONCLUSIONS

Although flow-diverter placement appears to be safe and effective on midterm follow-up in children, longer follow-up is critical. The current sizes of flow diverter devices and delivery systems cover the pediatric size range, obviating developing flow diverters specific to children.

Flow Diversion for Ophthalmic Artery Aneurysms

Endovascular treatments of ophthalmic segment aneurysms are commonly used but visual outcomes remain a concern. We performed a retrospective review of patients with carotid-ophthalmic aneurysms treated with flow diversion from June 2009 to June 2015. The following outcomes were studied through chart review: visual outcomes, complications, postoperative stroke and intraparenchymal hemorrhage, and clinical outcomes. Angiographic outcomes were studied with angiography and MRA at 6 months, 1 year, and 3 years. We evaluated 50 carotid-ophthalmic aneurysms in 48 patients, among whom 44 patients with 46 aneurysms underwent treatment. The mean clinical follow-up was 29 ± 22 months (range, 0-65 months). There were no permanent adverse visual outcomes. There was 1 death because of late intraparenchymal hemorrhage (2.2%). Six-month angiography showed complete occlusion in 24 of 37 patients (64.9%), and 3-year angiography results showed occlusion in 24 of 25 patients (96%). In conclusion, flow diversion is a safe and effective treatment for carotid-ophthalmic aneurysms in carefully selected patients. The risk of adverse visual outcomes is low, and most aneurysms progress to complete occlusion.

Balloon-in-stent assisted coiling for treatment of intracranial overwide and undertall aneurysms

This study reports our experience of balloon-in-stent assisted coiling for the treatment of morphologically unfavorable aneurysms located in the internal carotid artery (ICA). From July 2007 to April 2014, twelve patients with twelve aneurysms located in the ICA were coil embolized by simultaneously using balloon and stent assistance. Five aneurysms were ruptured and seven were unruptured. All the aneurysms were overwide (dome-to-neck ratio ⩽1.2) and undertall (aspect ratio ⩽1.2) anatomically. The procedure-related adverse events, clinical and angiographic results were retrospectively analyzed. Intraprocedural aneurysmal bleeding occurred for one unruptured aneurysm but was stopped immediately after the balloon was inflated. Periprocedural thromboembolism occurred for two ruptured aneurysms, leading to death in one patient and severe neurological deficit for the other one. Procedure-related permanent morbidity and mortality rates were 8.3% (1/12) and 8.3% (1/12). Satisfactory (total and subtotal) occlusion was obtained immediately in 11 (91.7%) cases. Nine aneurysms received digital subtraction angiography follow-up (mean 25.1months, range 6-55), and all of them except one were totally obliterated. No aneurysmal bleeding occurred during a mean period of 59.1months, clinical follow-up for eleven patients. Balloon-in-stent assisted coiling might be a therapeutic alternative to prevent growth or rupture of overwide and undertall aneurysms. Nevertheless, it should be used prudently for ruptured ICA aneurysms, for its disadvantage of technical complexity and relatively high rate of adverse events.

Does Arterial Flow Rate Affect the Assessment of Flow-Diverter Stent Performance?

BACKGROUND AND PURPOSE

Our aim was to assess the performance of flow-diverter stents. The pre- and end-of-treatment angiographies are commonly compared. However, the arterial flow rate may change between acquisitions; therefore, a better understanding of its influence on the local intra-aneurysmal hemodynamics before and after flow-diverter stent use is required.

MATERIALS AND METHODS

Twenty-five image-based aneurysm models extracted from 3D rotational angiograms were conditioned for computational fluid dynamics simulations. Pulsatile simulations were performed at different arterial flow rates, covering a wide possible range of physiologic flows among 1-5 mL/s. The effect of flow-diverter stents on intra-aneurysmal hemodynamics was numerically simulated with a porous medium model. Spatiotemporal-averaged intra-aneurysmal flow velocity and flow rate were calculated for each case to quantify the hemodynamics after treatment. The short-term flow-diverter stent performance was characterized by the relative velocity reduction inside the aneurysm.

RESULTS

Spatiotemporal-averaged intra-aneurysmal flow velocity before and after flow-diverter stent use is linearly proportional to the mean arterial flow rate (minimum R² > 0.983 of the linear regression models for untreated and stented models). Relative velocity reduction asymptotically decreases with increasing mean arterial flow rate. When the most probable range of arterial flow rate was considered (3-5 mL/s), instead of the wide possible flow range, the mean SD of relative velocity reduction was reduced from 3.6% to 0.48%.

CONCLUSIONS

Both intra-aneurysmal aneurysm velocity and flow-diverter stent performance depend on the arterial flow rate. The performance could be considered independent of the arterial flow rates within the most probable range of physiologic flows.

Early angiographic changes of intra-aneurysmal flow after flow-diverter stent treatment are not predictive of therapeutic success

BACKGROUND AND PURPOSE

Flow-diverter stents (FDS) are new devices for the endovascular treatment of intracranial aneurysms (IAs) promoting progressive aneurysmal thrombosis. To date, the delay of aneurysmal exclusion remains unclear. We evaluated the correlation between angiographic changes in the first 24 hours and 12-month occlusion in aneurysms treated with FDS.

METHODS

We retrospectively analyzed the intra-aneurysmal flow by evaluating the in-flow and out-flow delays on preoperative, immediate postoperative, 24-hour and 12-month follow-up angiography. Dichotomy of in-flow and out-flow within the aneurysm was considered as the time of contrast filling and time of contrast washing relatively to the parent artery. The delay times were compared and correlated with the therapeutic success of FDS at 12 months of follow-up.

RESULTS

Out of 14 treated IAs, in 13 consecutive patients, n = 10 (71%) aneurysms showed complete occlusion at 12 months. Between immediate postoperative and 24-hour control, 10 aneurysms (71%) demonstrated in-flow modification, with eight increasing, two decreasing and four having no change. There were no statistical differences in therapeutic success in relation to the different flow-related profiles of intra-aneurysmal flux.Out-flow modifications were found in 11 aneurysms (79%) between immediate postoperative and 24-hour control, with five increasing, six decreasing and three having no change. Similar to the in-flow changes, there were no statistical differences in therapeutic success relative to the flow-related profiles.

CONCLUSIONS

Early angiographic changes after FDS placement are very frequent, but are not correlated with the 12-month technical success of flow-diversion techniques.

P2Y12 Reaction Units: Effect on Hemorrhagic and Thromboembolic Complications in Patients With Cerebral Aneurysms Treated With the Pipeline Embolization Device

BACKGROUND

The main concern with the use of the pipeline embolization device (PED) in treating cerebral aneurysms is the risk of hemorrhagic and thromboembolic complications.

OBJECTIVE

To investigate if P2Y12 reaction unit (PRU) values are associated with hemorrhagic and thromboembolic complications after treatment with the PED and to find an optimal range of preprocedural PRU values.

METHODS

Two hundred thirty-one patients with 248 cerebral aneurysms treated with the PED were retrospectively identified. Patients were started on dual-antiplatelet treatment at least 10 days before the intervention. PRU values were checked. Univariate and multivariate logistic regression were performed. Youden Indices were calculated to determine cutoffs for optimal PRU values.

RESULTS

Mean patient age was 57 years. Mean last preprocedural PRU was 132 (range: 1-382). The combined rate of major hemorrhagic complications (4%) and major thromboembolic complications (5.6%) was 9.6%. Analysis using Youden indices suggested an optimal PRU range of 70 to 150 with higher odds of complications outside this range (P = .01, odds ratio [OR] = 3 [1.2-7.5]). PRU <60 was a significant predictor of hemorrhagic complications (P = .04, OR = 2.45 [1.01-5.9]) and PRU >240 was a significant predictor of any thromboembolic complication (P = .04, OR = 3.6 [1.04-12]) and cerebral thromboembolic complications (P = .02, OR = 4 [1.2-14]).

CONCLUSION

Target preoperative PRU values should be between 60 and 240 and ideally between 70 and 150. Values below this range and above it carry higher odds of hemorrhagic and thromboembolic complications, respectively.

Flow changes in the posterior communicating artery related to flow-diverter stents in carotid siphon aneurysms

BACKGROUND

Flow-diverter stent (FDS) placement for treatment of intracranial aneurysms can cause flow changes in the covered branches.

OBJECTIVE

To assess the impact of the treatment of carotid siphon aneurysms with FDS on the posterior communicating artery (PComA) flow.

MATERIALS AND METHODS

Between February 2011 and January 2015, 125 carotid siphon aneurysms were treated with FDS. We retrospectively analyzed all cases with PComA ostial coverage. The circle of Willis anatomy was also studied as the flow changes in PComA postoperatively and during angiographic follow-up. Data from neurological examination were also collected.

RESULTS

Eighteen aneurysms of the carotid siphon in 17 patients were treated with FDS covering the ostium of the PComA. Based on the initial angiography, patients were divided into two groups: the first with a P1/PComA size ratio >1 (10 cases) and the second with a ratio ≤1 (8 cases). Follow-up angiography (mean time of 10 months) showed 90% of PComA flow changes in group 1 but only 12.5% in group 2. There was a significant difference between the two groups (p=0.002). Nevertheless, no patient had new symptoms related to these flow changes during the follow-up period.

CONCLUSIONS

In our experience, covering the PComA by FDS when treating carotid siphon aneurysms appeared safe and the P1/PComA ratio is a good predictor of flow changes in PComA.

Fatal arterial rupture during angioplasty of a flow diverter in a recurrent, previously Y-stented giant MCA bifurcation aneurysm

BACKGROUND AND PURPOSE

A patient with a previously Y-stented giant left middle cerebral artery (MCA) bifurcation aneurysm returned with a recurrence.

MATERIALS AND METHODS

A flow diverter (FD) was deployed through one limb of the high-porosity Y-stenting construction. The proximal FD failed to expand and an attempt at balloon angioplasty led to fatal rupture of the MCA.

RESULTS

Autopsy demonstrated subarachnoid hemorrhage, vessel rupture and fracture of the proximal high-porosity stent. Microscopic photographs showed that the FD had failed to open because the guiding wire had inadvertently exited and re-entered the proximal segment of the high-porosity stent partially incorporated to the wall of the MCA. Balloon dilatation of the FD which had remained collapsed between the stent and the vessel wall caused fracture of the stent and rupture of the artery.

CONCLUSION

Angioplasty and flow-diversion of previously Y-stented aneurysms can lead to serious complications.

Very large and giant microsurgical bifurcation aneurysms in rabbits: Proof of feasibility and comparability using computational fluid dynamics and biomechanical testing

BACKGROUND

Giant aneurysms are challenging lesions with unacceptable high rates of aneurysm recanalization and rerupture following embolization. Reliable in vivo models are urgently needed to test the performance of new more efficient endovascular devices.

MATERIALS AND METHODS

Aneurysms were created in 11 New Zealand white rabbits (4.5-5.5kg): A long venous pouch (length 25-30mm) mimicking the aneurysm sac was derived from the external jugular vein and sutured into a microsurgically created bifurcation between both common carotid arteries. After 4 weeks the rabbits underwent 3T Magnetic resonance angiography (3T-MRA). Exemplary computational fluid dynamics (CFD) simulations were performed to compare the flow conditions of giant rabbit and human aneurysms. We used species-related boundary conditions, in particular, we measured blood viscosity values. Biaxial mechanical tests were performed for the mechanical characterization and comparison.

COMPARISON WITH EXISITING METHOD(S)

None.

RESULTS

No peri- or postoperative mortality was observed. 3T-MRA showed aneurysm patency in 10 out of 11 aneurysms (90.9%). Aneurysm lengths ranged from 21.5-25.6mm and aneurysm necks from 7.3-9.8mm. CFD showed complex flow profiles with multiple vortices in both, rabbit and human aneurysms. Lower blood viscosity values of the rabbit (3.92mPas vs. human 5.34mPas) resulted in considerable lower wall shear stress rates (rabbit 0.38Pa vs. human 1.66Pa). Mechanical tests showed lower stiffness of rabbit aneurysms compared to unruptured human aneurysms.

CONCLUSIONS

The proposed model showed favorable aneurysm patency rates, low morbidity and good hemodynamic comparability with complex flow patterns. Biomechanical testing suggests that experimental aneurysms might be even more fragile compared to human aneurysms.

Risk Factors for Visual Impairments in Patients with Unruptured Intradural Paraclinoid Aneurysms Treated by Neck Clipping without Bypass Surgery

OBJECTIVE

Although paraclinoid aneurysms are now frequently referred for endovascular treatment, the durability of obliteration is still to be determined. Therefore, direct surgery for paraclinoid aneurysms still remains indispensable. The present study aimed to evaluate the risk factors for the visual impairments in patients with unruptured intradural paraclinoid aneurysms.

METHODS

The data of 133 patients with 136 aneurysms treated by neck clipping without bypass surgery was evaluated. Visual impairments included decreased visual acuity and visual field defect. The aneurysm was classified into superior projecting aneurysm, ventral projecting aneurysm, and carotid cave aneurysm. Plug-in method was defined as filling interspace, which was formed between the internal carotid artery and the sutured dura in case of detachment of the dural ring.

RESULTS

Postoperative new visual impairments were observed in 30 aneurysms (22%). During the follow-up period (median, 600 days), postoperative new visual impairments continued in 23 aneurysms (17%). Multivariate analysis showed that carotid cave location and plug-in method were related to new visual impairments at 30 days (odds ratio [OR], 2.6; 95% confidence interval [CI] 1.1-6.1; P = 0.031 and OR, 4.1; 95% CI 1.4-12; P = 0.008) and at 6 months (OR, 4.1; 95% CI 1.5-11; P = 0.005 and OR, 3.3; 95% CI 1.1-11; P = 0.045).

CONCLUSIONS

The present study showed that carotid cave location and plug-in method during dural closures were related to postoperative continued visual impairments. Neurosurgeons should carefully consider the surgical indication for unruptured carotid cave aneurysms and avoid plug-in methods.

Silk flow diverter in the treatment of complex intracranial aneurysms: a single-center experience with 60 patients

BACKGROUND

Flow diverters are used to treat complex aneurysms that are not amenable to coiling. The aim of the present work was to retrospectively evaluate our experience with the Silk flow diverter. Technical nuances and complications are specifically discussed.

METHODS

Retrospectively data was collected on patients treated with Silk between October 2008 and October 2013.

RESULTS

Sixty patients harboring 67 aneurysms were treated using the Silk. Fifteen aneurysms were located in the posterior circulation and 52 in the anterior. A good angiographic result was achieved in 88 % (53/60) of the aneurysms available for imaging follow-up. There were ten treatment-related complications, 80 % were ischemic. Risk of complications increased with aneurysm size and in aneurysms of the posterior circulation.

CONCLUSIONS

Silk flow diverters are a good treatment option for aneurysms of the anterior circulation. Additional stents may be required in specific cases due to the Silk's low radial resistance. Treatment of giant fusiform aneurysms of the posterior circulation with Silk flow diverters is associated with a high rate of severe complications.

Patency of the anterior choroidal artery covered with a flow-diverter stent

OBJECT

The concept of the flow-diverter stent (FDS) is to induce aneurysmal thrombosis while preserving the patency of the parent vessel and any covered branches. In some circumstances, it is impossible to avoid dangerously covering small branches, such as the anterior choroidal artery (AChA), with the stent. In this paper, the authors describe the clinical and angiographic effects of covering the AChA with an FDS.

METHODS

Between April 2011 and July 2013, 92 patients with intracranial aneurysms were treated with the use of FDSs in the authors’ institution. For 20 consecutive patients (21.7%) retrospectively included in this study, this involved the unavoidable covering of the AChA with a single FDS during endovascular therapy. AChAs feeding the choroid plexus were classified as the long-course group (14 cases), and those not feeding the choroid plexus were classified as the short-course group (6 cases). Clinical symptoms and the angiographic aspect of the AChA were evaluated immediately after stent delivery and during follow-up. Neurological examinations were performed to rule out hemiparesis, hemihypesthesia, hemianopsia, and other cortical signs.

RESULTS

FDS placement had no immediate effect on AChA blood flow. Data were obtained from 1-month clinical follow-up in all patients and from midterm angiographic follow-up in 17 patients (85.0%), with a mean length of 9.8 ± 5.4 months. No patient in either group complained of transient or permanent symptoms related to an AChA occlusion. In all cases, the AChA remained patent without any flow changes.

CONCLUSIONS

The results of this study suggest that when impossible to avoid, the AChA may be safely covered with a single FDS during intracranial aneurysm treatment, irrespective of anatomy and anastomoses.

Pipeline Embolization Device in the Treatment of Recurrent Previously Stented Cerebral Aneurysms

BACKGROUND AND PURPOSE

The use of the Pipeline Embolization Device in the management of recurrent previously stented cerebral aneurysms is controversial. The aim of this study was to evaluate the efficacy and safety of the Pipeline Embolization Device in the treatment of recurrent, previously stented aneurysms.

MATERIALS AND METHODS

Twenty-one patients with previously stented recurrent aneurysms who later underwent Pipeline Embolization Device placement (group 1) were retrospectively identified and compared with 63 patients who had treatment with the Pipeline Embolization Device with no prior stent placement (group 2). Occlusion at the latest follow-up angiogram, recurrence and retreatment rates, clinical outcome, complications, and morbidity and mortality observed after treatment with the Pipeline Embolization Device were analyzed.

RESULTS

Patient characteristics were similar between the 2 groups. The mean time from stent placement to recurrence was 25 months. Pipeline Embolization Device treatment resulted in complete aneurysm occlusion in 55.6% of patients in group 1 versus 80.4% of patients in group 2 (P = .036). The retreatment rate in group 1 was 11.1% versus 7.1% in group 2 (P = .62). The rate of good clinical outcome at the latest follow-up in group 1 was 81% versus 93.2% in group 2 (P = .1). Complications were observed in 14.3% of patients in group 1 and 9.5% of patients in group 2 (P = .684).

CONCLUSIONS

The use of the Pipeline Embolization Device in the management of previously stented aneurysms is less effective than the use of this device in nonstented aneurysms. Prior stent placement can worsen the safety and efficacy profile of this device.

A New Protocol for Anticoagulation With Tirofiban During Flow Diversion

BACKGROUND:

Flow diversion is increasingly used to treat intracranial aneurysms. In previous reports, patients were pretreated with aspirin and clopidogrel before the intervention for the prevention of thromboembolic complications.

OBJECTIVE:

To assess the safety and efficacy of a new protocol for anticoagulation using tirofiban during flow diversion.

METHODS:

All patients received a 0.10–μg.kg−1.min−1 maintenance infusion of tirofiban intraoperatively without a loading dose. All patients were loaded with aspirin (325 mg) and clopidogrel (600 mg) just before the procedure or intraoperatively. No patient was pretreated with aspirin or clopidogrel. Thromboembolic and hemorrhagic complications were recorded.

RESULTS:

A total of 46 patients were treated with this protocol. Six patients (13%) had sustained a subarachnoid hemorrhage and were treated with the Pipeline Embolization Device within 24 hours of aneurysm rupture. The mean number of devices was 1.2 ± 0.66; adjunctive coiling was performed in 3 patients (6.5%). There were 2 complications (4.3%), 1 thromboembolic (2.2%) and 1 hemorrhagic (2.2%; monocular vision loss from occlusion of the central retinal artery in 1 patient and a parenchymal hemorrhage managed conservatively in another patient). No patient developed thrombocytopenia or retroperitoneal, gastrointestinal, or genitourinary bleeding. Of 46 patients, 44 (95.7%) had a modified Rankin Scale score of 0 to 2 at their follow-up visit.

CONCLUSION:

A protocol of anticoagulation with tirofiban during flow diversion has an excellent safety profile. This protocol provides a reasonable alternative to pretreatment with aspirin and clopidogrel and is useful in patients with ruptured aneurysms or when the use of a stent is unexpected.

Comparison of the flow diverter and stent-assisted coiling in large and giant aneurysms: safety and efficacy based on a propensity score-matched analysis

OBJECTIVES

The flow diverter (FD) is a device aimed at reconstructing the parent artery and occluding an aneurysm. We performed a propensity score-matched analysis to compare safety and efficacy between the FD and stent-assisted coiling.

METHODS

A database review was conducted to identify patients with large and giant unruptured aneurysms (aneurysms located in the ACA, MCA, or PCA were excluded) treated with the FD or stent-assisted coiling. A propensity score, representing the probability of using the FD, was generated for each aneurysm using the relevant patient and aneurysmal variables. Angiographic results, complications, and clinical outcomes were compared.

RESULTS

Forty-five aneurysms treated with the FD (FD alone: 32; FD+Coils: 13) and 45 treated with stent-assisted coiling were matched. The rate of complete occlusion was significantly (P = 0.0002) higher in the FD cohort than the conventional stent cohort at the 6-month follow-up. The FD cohort achieved greater improvement (P < 0.0001) and a lower rate of recurrence (P = 0.0001). The rate of periprocedural complications was similar, as was the proportion of patients who attained mRS ≤ 2 at discharge and at the 6-month follow-up.

CONCLUSIONS

Our findings provide reliable evidence demonstrating that the FD may be a preferred treatment option for large and giant unruptured aneurysms.

KEY POINTS

• Flow Diverter provided a higher complete occlusion rate at 6-month follow-up. • Flow Diverter achieved more progress occlusion and less recurrence. • Compared with the conventional stents, procedure-related morbidity of Flow Diverter was similar. • Flow Diverter is a preferred treatment for large and giant unruptured aneurysms.

Extraintracranial Bypass as a Rescue Therapy for Symptomatic Flow Diverter Thrombosis

A 56-year-old female with a giant partially thrombosed unruptured carotid-ophthalmic aneurysm was treated with a Pipeline flow diverter. Three months after the procedure, in concomitance with the discontinuation of one of the antiplatelet medications, the patient suffered from a minor stroke and relapsing transient ischemic attacks. The angiography demonstrated the occlusion of the internal carotid artery, and a perfusion-weighted CT scan showed a condition of hypoperfusion. The patient underwent a double-barrel extraintracranial bypass. The postoperative course was uneventful and she has experienced no further ischemic events to date.

Anterior Optic Pathway Compression Due to Internal Carotid Artery Aneurysms: Neurosurgical Management and Outcomes

Background and Purpose

Compression of the anterior optic pathway results in visual deficits that can lead to the detection of unruptured aneurysms in the internal carotid artery (ICA). The general types of treatment modalities for aneurysms and visual deficits include surgery and endosaccular coiling. This study retrospectively analyzed and compared the resolution of visual deficits following surgery or endosaccular coiling.

Methods

We reviewed data on 33 patients with unruptured ICA aneurysms who presented with visual field deficits caused by mass effects over the anterior optic pathway. Statistical analyses were performed to identify the variables associated with the recovery of visual symptoms.

Results

Eighteen patients underwent aneurysm clipping, 2 underwent bypass surgery with endovascular trapping, and 2 underwent endovascular trapping without bypass surgery (group A). Ten patients received endosaccular coiling (group B). The visual outcomes included the following: in group A, 17 patients (73.9%) demonstrated improvement and 6 patients (26.1%) demonstrated no changes or worse outcomes; in group B, 2 patients (20.0%) demonstrated improvement and 8 patients (80.0%) demonstrated no changes or worse outcomes. Group A was associated with a higher rate of favorable outcome than group B (P = 0.007). According to the multivariate analysis, treatment without endosaccular coiling (group A) was the only variable significantly associated with improvement of visual outcome (P = 0.005; OR = 28.523; 95% CI = 2.683-303.171).

Conclusions

Treatment modality was the only predictor of improvement in visual deficits. Treatment without endosaccular coiling resulted in visual improvement significantly more often in comparison with endosaccular coiling.

Flow-Diverter Stents for the Treatment of Saccular Middle Cerebral Artery Bifurcation Aneurysms

BACKGROUND AND PURPOSE

The flow-diverter stent has been proved a feasible, safe, and efficient technique, particularly for the treatment of large and broad-neck carotid siphon aneurysms. Wide-neck bifurcation aneurysms remain, in some cases, a challenge for neurointerventionalists. We report the outcomes of the treatment of saccular middle cerebral artery bifurcation aneurysms with flow diversion in our institution.

MATERIALS AND METHODS

From the institution data base, all saccular, nondissecting MCA bifurcation aneurysms, treated with flow-diverter stents, were retrospectively reviewed. Technical issues, immediate posttreatment and follow-up angiographic findings, and clinical outcomes were assessed.

RESULTS

Fourteen patients with 15 aneurysms were included in the study. Ischemic complications, as confirmed by MR imaging, occurred in 6 patients (43%). Procedure-related morbidity and mortality at last follow-up were 21% and 0%, respectively. Angiographic follow-up was available for 13 aneurysms, with a mean follow-up of 16 months. Complete occlusion was obtained for 8 aneurysms (62%).

CONCLUSIONS

Compared with other available therapeutic options, the flow-diverter stent does not appear to be a suitable solution for the treatment of saccular MCA bifurcation aneurysms.

Initial Experience with p64: A Novel Mechanically Detachable Flow Diverter for the Treatment of Intracranial Saccular Sidewall Aneurysms

BACKGROUND AND PURPOSE

Flow diverters are important tools for the treatment of intracranial aneurysms. We report a retrospective evaluation of the safety and efficacy of p64, a fully resheathable, detachable flow diverter, in the endovascular treatment of intracranial sidewall aneurysms.

MATERIALS AND METHODS

Results of 121 patients with 130 aneurysms (median neck size, 3 mm; median fundus size, 4 mm), treated from April 2012 through October 2014, were analyzed. Aneurysms were unruptured or beyond the acute SAH phase. Thirteen aneurysms were located in the posterior circulation. Twenty-three aneurysms had previous saccular treatment but no previous parent vessel stent placement. In 19 aneurysms, a combination of coiling and flow diversion was performed.

RESULTS

Successful p64 deployment was achieved in 127/130 aneurysms. The average number of p64s used was 1.1 per aneurysm. The rates of transient and permanent morbidity and mortality were 5%, 1.7%, and 0.8%, respectively. Three-month DSA follow-up in 123/130 aneurysms showed complete occlusion in 58.5%. Nine-month DSA follow-up in 93/106 (87.7%) eligible aneurysms showed complete occlusion in 79.6%. Late follow-up (median, 496 days) has already been performed in 35 aneurysms, showing complete occlusion in 30 (85.7%).

CONCLUSIONS

p64 offers an efficacious treatment option for intracranial sidewall aneurysms with a high aneurysm occlusion and an acceptable complication rate. The possibility of repositioning or removing the device was an advantage. The higher attenuation may lead to fewer devices per case and early aneurysm occlusion. Long-term follow-up data are pending.

Grading of Regional Apposition after Flow-Diverter Treatment (GRAFT): a comparative evaluation of VasoCT and intravascular OCT

Background

Poor vessel wall apposition of flow diverter (FD) stents poses risks for stroke-related complications when treating intracranial aneurysms, necessitating long-term surveillance imaging. To facilitate quantitative evaluation of deployed devices, a novel algorithm is presented that generates intuitive two-dimensional representations of wall apposition from either high-resolution contrast-enhanced cone-beam CT (VasoCT) or intravascular optical coherence tomography (OCT) images.

Methods

VasoCT and OCT images were obtained after FD implant (n=8 aneurysms) in an experimental sidewall aneurysm model in canines. Surface models of the vessel wall and FD device were extracted, and the distance between them was presented on a two-dimensional flattened map. Maps and cross-sections at potential locations of malapposition detected on VasoCT-based maps were compared. The performance of OCT-based apposition detection was evaluated on manually labeled cross-sections using logistic regression against a thresholded (≥0.25 mm) apposition measure.

Results

VasoCT and OCT acquisitions yielded similar Grading of Regional Apposition after Flow-Diverter Treatment (GRAFT) apposition maps. GRAFT maps from VasoCT highlighted 16 potential locations of malapposition, of which two were found to represent malapposed device struts. Logistic regression showed that OCT could detect malapposition with a sensitivity of 98% and a specificity of 81%.

Conclusions

GRAFT delivered quantitative and visually convenient representations of potential FD malapposition and occasional acute thrombus formation. A powerful combination for future neuroendovascular applications is foreseen with the superior resolution delivered by intravascular OCT.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a worldwide health burden with high fatality and permanent disability rates. The overall prognosis depends on the volume of the initial bleed, rebleeding, and degree of delayed cerebral ischemia (DCI). Cardiac manifestations and neurogenic pulmonary edema indicate the severity of SAH. The International Subarachnoid Aneurysm Trial (ISAT) reported a favorable neurological outcome with the endovascular coiling procedure compared with surgical clipping at the end of 1 year. The ISAT trial recruits were primarily neurologically good grade patients with smaller anterior circulation aneurysms, and therefore the results cannot be reliably extrapolated to larger aneurysms, posterior circulation aneurysms, patients presenting with complex aneurysm morphology, and poor neurological grades. The role of hypothermia is not proven to be neuroprotective according to a large randomized controlled trial, Intraoperative Hypothermia for Aneurysms Surgery Trial (IHAST II), which recruited patients with good neurological grades. Patients in this trial were subjected to slow cooling and inadequate cooling time and were rewarmed rapidly. This methodology would have reduced the beneficial effects of hypothermia. Adenosine is found to be beneficial for transient induced hypotension in 2 retrospective analyses, without increasing the risk for cardiac and neurological morbidity. The neurological benefit of pharmacological neuroprotection and neuromonitoring is not proven in patients undergoing clipping of aneurysms. DCI is an important cause of morbidity and mortality following SAH, and the pathophysiology is likely multifactorial and not yet understood. At present, oral nimodipine has an established role in the management of DCI, along with maintenance of euvolemia and induced hypertension. Following SAH, hypernatremia, although less common than hyponatremia, is a predictor of poor neurological outcome.

Republished: Successful treatment of a giant pediatric fusiform basilar trunk aneurysm with surpass flow diverter

Fusiform aneurysms present a unique challenge to traditional microsurgical and endovascular treatment because of the lack of a discernible neck and the involvement of parent vessel. Flow diversion has increasingly become the treatment of choice for fusiform aneurysms in the anterior circulation, but its results in the posterior circulation are variable. We report successful treatment of a giant fusiform upper basilar trunk aneurysm with the Surpass flow diverter in an adolescent, and discuss the potential advantages of this emerging technology in the treatment of fusiform posterior circulation aneurysms.

Successful treatment of a giant pediatric fusiform basilar trunk aneurysm with surpass flow diverter

Fusiform aneurysms present a unique challenge to traditional microsurgical and endovascular treatment because of the lack of a discernible neck and the involvement of parent vessel. Flow diversion has increasingly become the treatment of choice for fusiform aneurysms in the anterior circulation, but its results in the posterior circulation are variable. We report successful treatment of a giant fusiform upper basilar trunk aneurysm with the Surpass flow diverter in an adolescent, and discuss the potential advantages of this emerging technology in the treatment of fusiform posterior circulation aneurysms.

Flow diversion treatment of complex bifurcation aneurysms beyond the circle of Willis: a single-center series with special emphasis on covered cortical branches and perforating arteries

BACKGROUND

Data regarding anatomic and clinical results of flow diversion treatment in complex bifurcation aneurysms of the anterior circulation are scarce.

OBJECTIVE

To present our results of treatment of these lesions with special emphasis on the fate of 'jailed' cortical branches and perforating arteries.

METHODS

Seventeen patients were treated with flow diverters (FDs) for 18 aneurysms of the middle cerebral artery bifurcation (n=13) and the anterior communicating artery complex (n=5). Nineteen cortical branches were covered. A single FD was used in all patients.

RESULTS

At latest follow-up (mean 7.9 months; range 3-36; median 4.0) 2/19 (10.5%) of the covered branches were occluded, 9/19 (47.4%) showed a decreased caliber and the remaining branches were unchanged. All branch modifications were clinically asymptomatic. Mortality and permanent morbidity were 0%. Symptomatic ischemic events in perforator territories occurred in three patients (17.6%), which were reversible in all of them within 24 h. Follow-up MRI disclosed asymptomatic lacunar defects corresponding to covered perforating artery territories in five patients (29.4%). Altogether, perforator lesions-symptomatic and asymptomatic-occurred in 7/17 patients (41.2%). 33.3% of the aneurysms were occluded at latest follow-up; decreased diameters were seen in the other 66.7%.

CONCLUSIONS

Flow diversion of bifurcation aneurysms is feasible with low rates of permanent morbidity and mortality. Caliber reduction and asymptomatic occlusion of covered cortical branches seems to be common, yet ischemic complications are rather linked to perforator occlusions. Our results on aneurysm occlusion rates are preliminary and longer follow-up periods are warranted.

Which spring is the best? Comparison of methods for virtual stenting

This paper presents a methodology for modeling the deployment of implantable devices used in minimally invasive vascular interventions. Motivated by the clinical need to perform preinterventional rehearsals of a stent deployment, we have developed methods enabling virtual device placement inside arteries, under the constraint of real-time application. This requirement of rapid execution narrowed down the search for a suitable method to the concept of a dynamic mesh. Inspired by the idea of a mesh of springs, we have found a novel way to apply it to stent modeling. The experiments conducted in this paper investigate properties of the stent models based on three different spring types: lineal, semitorsional, and torsional springs. Furthermore, this paper compares the results of various deployment scenarios for two different classes of devices: a stent graft and a flow diverter. The presented results can be of a high-potential clinical value, enabling the predictive evaluation of the outcome of a stent deployment treatment.

Patency of the anterior choroidal artery after flow-diversion treatment of internal carotid artery aneurysms

BACKGROUND AND PURPOSE

Treatment of cerebral aneurysms with flow diverters often mandates placement of the device across the ostia of major branches of the internal carotid artery. We determined the patency rates of the anterior choroidal artery after placement of flow-diversion devices across its ostium.

MATERIALS AND METHODS

We analyzed a consecutive series of patients in whom a Pipeline Embolization Device was placed across the ostium of an angiographically visible anterior choroidal artery while treating the target aneurysm. Patency of the anterior choroidal artery after Pipeline Embolization Device placement was determined at immediate postoperative and follow-up angiography. Data on pretreatment aneurysm rupture status, concomitant coiling, number of Pipeline Embolization Devices used, neurologic status at follow-up, and follow-up MR imaging/CT findings were collected.

RESULTS

Fifteen patients with 15 treated aneurysms were included in this study. In the immediate postprocedural setting, the anterior choroidal artery was patent on posttreatment angiography for all 15 patients. Of the 14 patients with follow-up angiography at least 6 months after Pipeline Embolization Device placement, 1 (7%) had occlusion of the anterior choroidal artery and 14 had a patent anterior choroidal artery (93%). No patients had new neurologic symptoms or stroke related to anterior choroidal artery occlusion at follow-up. Of the 9 patients with follow-up CT or MR imaging, none had infarction in the vascular territory of the anterior choroidal artery.

CONCLUSIONS

In this small study, placement of a Pipeline Embolization Device across the anterior choroidal artery ostium resulted in occlusion of the artery in only 1 patient. It was not associated with ischemic changes in the distribution of the anterior choroidal artery in any patient.

Visual outcomes with flow-diverter stents covering the ophthalmic artery for treatment of internal carotid artery aneurysms

BACKGROUND AND PURPOSE

Flow-diverting stents can be used to treat intracranial aneurysms that are not amenable to treatment with coils. We analyzed ophthalmic consequences due to coverage of the origin of the ophthalmic artery by flow-diverting stents for the treatment of internal carotid artery aneurysms.

MATERIALS AND METHODS

From April 2009 to April 2013, the clinical and angiographic outcomes of all 28 patients treated for aneurysms with flow-diverting stents covering the origin of the ophthalmic artery were prospectively collected. The origin of the ophthalmic artery in relation to the target aneurysm was classified by using a 4-type classification. A complete ophthalmic examination was performed by a single ophthalmologist 48 hours before and 1 week after covering the ophthalmic artery.

RESULTS

Ophthalmic artery patency was normal at the end of endovascular treatment in 24/28 cases (85.7%). With extensive ophthalmic examinations, 11 patients (39.3%) showed new ophthalmic complications. Patients with the ophthalmic artery originating from the aneurysm sac were at high risk for retinal emboli (4/5, 80%). Patients with the ophthalmic artery originating from the inner curve of the carotid siphon were at high risk for optic nerve ischemic atrophy (3/4, 75%).

CONCLUSIONS

This prospective study shows that covering the ophthalmic artery with a flow-diverting stent is not without potential complications. Ophthalmic complications can occur but are often not diagnosed. The anatomic disposition of the ophthalmic artery in relation to the carotid siphon and aneurysm should be clearly understood because some configurations have a higher risk. When not required, covering of the ophthalmic artery by flow-diverting stents should be avoided.

Safety and efficacy of the Pipeline Embolization Device in 100 small intracranial aneurysms

OBJECT Flow diverters are increasingly used for treatment of intracranial aneurysms. In most series, the Pipeline Embolization Device (PED) was used for the treatment of large, giant, complex, and fusiform aneurysms. Little is known about the use of the PED in small aneurysms. The purpose of this study was to assess the safety and efficacy of the PED in small aneurysms (≤ 7 mm). METHODS A total of 100 consecutive patients were treated with the PED at the authors' institution between May 2011 and September 2013. Data on procedural safety and efficacy were retrospectively collected. RESULTS The mean aneurysm size was 5.2 ± 1.5 mm. Seven patients (7%) had sustained a subarachnoid hemorrhage. All except 5 aneurysms (95%) arose from the anterior circulation. The number of PEDs used was 1.2 per aneurysm. Symptomatic procedure-related complications occurred in 3 patients (3%): 1 distal parenchymal hemorrhage that was managed conservatively and 2 ischemic events. At the latest follow-up (mean 6.3 months), 54 (72%) aneurysms were completely occluded (100%), 10 (13%) were nearly completely occluded (≥ 90%), and 11 (15%) were incompletely occluded (< 90%). Six aneurysms (8%) required further treatment. Increasing aneurysm size (OR 3.8, 95% CI 0.99-14; p = 0.05) predicted retreatment. All patients achieved a favorable outcome (modified Rankin Scale Score 0-2) at follow-up. CONCLUSIONS In this study, treatment of small aneurysms with the PED was associated with low complication rates and high aneurysm occlusion rates. These findings suggest that the PED is a safe and effective alternative to conventional endovascular techniques for small aneurysms. Randomized trials with long-term follow-up are necessary to determine the optimal treatment that leads to the highest rate of obliteration and the best clinical outcomes.

Extra-aneurysmal flow modification following pipeline embolization device implantation: focus on regional branches, perforators, and the parent vessel

BACKGROUND AND PURPOSE

Flow-diverter technology has proved to be a safe and effective treatment for intracranial aneurysm based on the concept of flow diversion allowing parent artery and collateral preservation and aneurysm healing. We investigated the patency of covered side branches and flow modification within the parent artery following placement of the Pipeline Embolization Device in the treatment of intracranial aneurysms.

MATERIALS AND METHODS

Sixty-six aneurysms in 59 patients were treated with 96 Pipeline Embolization Devices. We retrospectively reviewed imaging and clinical results during the postoperative period at 6 and 12 months to assess flow modification through the parent artery and side branches. Reperfusion syndrome was assessed by MR imaging and clinical evaluation.

RESULTS

Slow flow was observed in 13 of 68 (19.1%) side branches covered by the Pipeline Embolization Device. It was reported in all cases of anterior cerebral artery coverage, in 3/5 cases of M2-MCA coverage, and in 5/34 (14.7%) cases of ophthalmic artery coverage. One territorial infarction was observed in a case of M2-MCA coverage, without arterial occlusion. One case of deep Sylvian infarct was reported in a case of coverage of MCA perforators. Two ophthalmic arteries (5.9%) were occluded, and 11 side branches (16.2%) were narrowed at 12 months' follow-up; patients remained asymptomatic. Parent vessel flow modification was responsible for 2 cases (3.4%) of reperfusion syndrome. Overall permanent morbidity and mortality rates were 5.2% and 6.9%, respectively. We did not report any permanent deficit or death in case of slow flow observed within side branches.

CONCLUSIONS

After Pipeline Embolization Device placement, reperfusion syndrome was observed in 3.4%, and territorial infarction, in 3.4%. Delayed occlusion of ophthalmic arteries and delayed narrowing of arteries covered by the Pipeline Embolization Device were observed in 5.9% and 16.2%, respectively. No permanent morbidity or death was related to side branch coverage at midterm follow-up.

Technology developments in endovascular treatment of intracranial aneurysms

Advances in the management and endovascular treatment of intracranial aneurysms are progressing at a tremendous rate. Developments in novel imaging technology may improve diagnosis, risk stratification, treatment planning, intraprocedural assessment, and follow-up evaluation. Evolution of devices, including microwires, microcatheters, balloons, stents, and novel scaffolding devices, has greatly expanded the potential to treat difficult aneurysms. Although developments in technology have greatly improved the efficiency and efficacy of treatment of neurovascular disorders, novel devices do not always improve outcomes and may be associated with unique complications. As such, it is paramount to have an in-depth understanding of new devices and the implications of their introduction into clinical practice. This review provides an update on developments in endovascular treatment of intracranial aneurysms.

Relationship between aneurysm occlusion and flow diverting device oversizing in a rabbit model

BACKGROUND AND PURPOSE

Implanted, actual flow diverter pore density is thought to be strongly influenced by proper matching between the device size and parent artery diameter. The objective of this study was to characterize the correlation between device sizing, metal coverage, and the resultant occlusion of aneurysms following flow diverter treatment in a rabbit model.

METHODS

Rabbit saccular aneurysms were treated with flow diverters (iso-sized to proximal parent artery, 0.5 mm oversized, or 1.0 mm oversized, respectively, n=6 for each group). Eight weeks after implantation, the angiographic degree of aneurysm occlusion was graded (complete, near-complete, or incomplete). The ostium of the explanted aneurysm covered with the flow diverter struts was photographed. Based on gross anatomic findings, the metal coverage and pore density at the ostium of the aneurysm were calculated and correlated with the degree of aneurysm occlusion.

RESULTS

Angiographic results showed there were no statistically significant differences in aneurysm geometry and occlusion among groups. The mean parent artery diameter to flow diverter diameter ratio was higher in the 1.0 mm oversized group than in the other groups. Neither the percentage metal coverage nor the pore density showed statistically significant differences among groups. Aneurysm occlusion was inversely correlated with the ostium diameter, irrespective of the size of the device implanted.

CONCLUSIONS

Device sizing alone does not predict resultant pore density or metal coverage following flow diverter implantation in the rabbit aneurysm model. Aneurysm occlusion was not impacted by either metal coverage or pore density, but was inversely correlated with the diameter of the ostium.

Treatment of giant and large fusiform middle cerebral artery aneurysms with excision and interposition radial artery graft in a 4-year-old child: case report

BACKGROUND AND IMPORTANCE

We report an unusual case of complex giant and large fusiform aneurysms not amenable for clipping or coiling in a 4-year-old child managed with aneurysm resection and radial artery interposition graft.

CLINICAL PRESENTATION

A 4-year-old child presented with repeated severe headache and vomiting. Computed tomography, magnetic resonance imaging, and magnetic resonance angiography and digital subtraction angiography showed a giant fusiform aneurysm on the right middle cerebral artery (MCA). Because of the complex shape, endovascular treatment or clip reconstruction was not possible, and a bypass procedure was planned. Right frontotemporal craniotomy and orbitotomy was performed. Two aneurysms involving the M1 segment of the MCA were found in line, 1 giant, and the other large in size. The aneurysms were resected and treated with short radial artery interposition graft, which was narrower than the proximal or distal MCA. The child recovered normally, and the bypass was patent after 1 year.

CONCLUSION

Large fusiform MCA aneurysms may be difficult to treat, but there are treatment options that include a bypass procedure. Resection and short interposition radial artery graft is an excellent but rare treatment option in a very young child. This was a very successful treatment in this child.

Intra-aneurysmal thrombus modification after flow-diversion

Flow diversion has been successfully used to treat large and giant intracranial aneurysms that present with mass effect. We conducted a retrospective review, evaluating the modification of thrombi in this aneurysm type after treatment with the Pipeline Embolization Device (ev3 Endovascular, Plymouth, MN, USA) and the effects of these modifications on symptoms. Eight patients, seven of whom were female, harbored eight partially thrombosed large or giant aneurysms. Five of the eight aneurysms presented with symptomatic mass effect. At 1 year follow-up, complete occlusion occurred in 75% (6/8) of patients. On average, the longest thrombus diameter measured 22.31 mm before treatment and 14.05 mm 1 year afterwards. Seven of the eight thrombi regressed, as did their aneurysms. All six patients with shrunken thrombi had tremendous symptom improvement and became asymptomatic in the following year. The current findings seem to reflect the size variation of the intra-aneurysmal thrombus rather than the size of the aneurysm itself.

Clinical practice guideline for the management of intracranial aneurysms

Purpose

An intracranial aneurysm, with or without subarachnoid hemorrhage (SAH), is a relevant health problem. The rupture of an intracranial aneurysm is a critical concern for individual health; even an unruptured intracranial aneurysm is an anxious condition for the individual. The aim of this guideline is to present current and comprehensive recommendations for the management of intracranial aneurysms, with or without rupture.

Materials and Methods

We performed an extensive literature search, using Medline. We met in person to discuss recommendations. This document is reviewed by the Task Force Team of the Korean Society of Interventional Neuroradiology (KSIN).

Results

We divided the current guideline for ruptured intracranial aneurysms (RIAs) and unruptured intracranial aneurysms (UIAs). The guideline for RIAs focuses on diagnosis and treatment. And the guideline for UIAs focuses on the definition of a high-risk patient, screening, principle for treatment and selection of treatment method.

Conclusion

This guideline provides practical, evidence-based advice for the management of patients with an intracranial aneurysm, with or without rupture.

The 'Sphere': A Dedicated Bifurcation Aneurysm Flow-Diverter Device

We present flow-based results from the early stage design cycle, based on computational modeling, of a prototype flow-diverter device, known as the 'Sphere', intended to treat bifurcation aneurysms of the cerebral vasculature. The device is available in a range of diameters and geometries and is constructed from a single loop of NITINOL^® wire. The 'Sphere' reduces aneurysm inflow by means of a high-density, patterned, elliptical surface that partially occludes the aneurysm neck. The device is secured in the healthy parent vessel by two armatures in the shape of open loops, resulting in negligible disruption of parent or daughter vessel flow. The device is virtually deployed in six anatomically accurate bifurcation aneurysms: three located at the Basilar tip and three located at the terminus bifurcation of the Internal Carotid artery (at the meeting of the middle cerebral and anterior cerebral arteries). Both steady state and transient flow simulations reveal that the device presents with a range of aneurysm inflow reductions, with mean flow reductions falling in the range of 30.6-71.8% across the different geometries. A significant difference is noted between steady state and transient simulations in one geometry, where a zone of flow recirculation is not captured in the steady state simulation. Across all six aneurysms, the device reduces the WSS magnitude within the aneurysm sac, resulting in a hemodynamic environment closer to that of a healthy vessel. We conclude from extensive CFD analysis that the 'Sphere' device offers very significant levels of flow reduction in a number of anatomically accurate aneurysm sizes and locations, with many advantages compared to current clinical cylindrical flow-diverter designs. Analysis of the device's mechanical properties and deployability will follow in future publications.

Periprocedural and mid-term technical and clinical events after flow diversion for intracranial aneurysms

OBJECT

Flow diversion has emerged as a promising treatment alternative for cerebral aneurysms. As a new device, treatment-related events and complications are currently being characterized.

METHODS

Data on 100 consecutive procedures with the intention to use flow diversion were prospectively collected and analyzed retrospectively.

RESULTS

Ninety-five aneurysms were treated in 93 patients during 100 consecutive procedures in which the intention was to treat an intracranial aneurysm with flow diversion. Death occurred in 1% and permanent morbidity in 1%. However, periprocedural technical complications occurred in 35% of the procedures and included proximal device migration in 12%, incomplete device expansion in 9%, catheter-induced vasospasm in 6%, and artery perforation from the wire in 3%. Perioperative clinical events were seen in 28% (thromboembolism and access site complications were the most common, being observed in 6.5% of patients). Worsened extraocular motility was seen in 5.4% and resolved in 4/5 patients. Mean clinical follow-up was 17 months. There were no late clinical or technical issues resulting in permanent deficits, although one patient suffered worsening ataxia. Overall, using very strict angiographic criteria, complete angiographic obliteration was 50% at 6 months and 69% after 1 year.

CONCLUSIONS

Flow diversion for intracranial aneurysms is a safe and effective treatment. Technical and clinical events are common in the perioperative period. Careful perioperative care and proper management of technical and clinical events encountered is key to achieving low morbidity and mortality. Late clinical events can occur but are unlikely to result in permanent complications.

The success of flow diversion in large and giant sidewall aneurysms may depend on the size of the defect in the parent artery

BACKGROUND AND PURPOSE

Flow diverters are designed to occlude aneurysms while preserving flow to jailed arterial branches. We postulated that treatment success depended on the size of the aneurysm ostium or defect in the parent artery.

MATERIALS AND METHODS

Flow diverter expansion and deformation were studied in silicone tubes with wall apertures of various sizes. Large and giant canine sidewall aneurysms, featuring a branch located immediately opposite the aneurysm, and a smaller 6- to 8-mm (group A, n = 6) or a larger 10- to 16-mm (group B, n = 6) ostium were created to study the effects of ostium size on aneurysm or branch occlusion by flow diverters. Angiographic results after deployment and at 3 months were scored by using an ordinal scale. The amount of neointima formation on the segment of the device overlying the aneurysm or the branch ostia was determined by specimen photography.

RESULTS

The fusiform deformation of flow diverters was maximal with larger defects in silicone tubes. At 3 months, group B aneurysms showed worse angiographic results than group A aneurysms, with larger residual aneurysm volumes (P = .002). Neointimal coverage of the aneurysm ostia was more complete in group A compared with group B (P = .002).

CONCLUSIONS

The effects of flow diversion may vary with the size of the aneurysm ostium.

Endovascular treatment of internal carotid artery bifurcation aneurysms: a single-center experience and a systematic review and meta-analysis

BACKGROUND AND PURPOSE

Endovascular coiling of internal carotid artery bifurcation aneurysms can be challenging due to unfavorable morphologic features. With improvements in endovascular techniques, several series have detailed the results and complications of endovascular treatment of aneurysms at this location. We performed a systematic review and meta-analysis of published series on the endovascular treatment of ICA bifurcation aneurysms, including a tertiary referral center experience.

MATERIALS AND METHODS

We performed a comprehensive literature search for reports on contemporary endovascular treatment of ICA bifurcation aneurysms from 2000 to 2013, and we reviewed our experience. We extracted information regarding periprocedural complications, procedure-related morbidity and mortality, immediate angiographic outcome, long-term clinical and angiographic outcome, and retreatment rate. Event rates were pooled across studies by using random-effects meta-analysis.

RESULTS

Including our series of 37 patients, 6 studies with 158 patients were analyzed. Approximately 60% of the aneurysms presented as unruptured; 88.0% (95% CI, 68.0%-96.0%) of aneurysms showed complete or near-complete occlusion at immediate postoperative angiography compared with 82.0% (95% CI, 73.0%-88.0%) at last follow-up. The procedure-related morbidity and mortality were 3.0% (95% CI, 1.0%-7.0%) and 3.0% (95% CI, 1.0%-8.0%), respectively. The retreatment rate was 14.0% (95% CI, 8.0%-25.0%). Good neurologic outcome was achieved in 93.0% (95% CI, 86.0%-97.0%) of patients.

CONCLUSIONS

Endovascular treatment of ICA bifurcation aneurysms is feasible and effective and is associated with high immediate angiographic occlusion rates. However, retreatment rates and procedure-related morbidity and mortality are non-negligible.

Treatment of intracranial aneurysms by flow diverter devices: long-term results from a single center

OBJECTIVES

Flow-Diverter Devices (FDD) are a new generation stents designed for the treatment of the intracranial aneurysms. This article reports the long-term results (2-4 years) of this treatment from a single-center.

METHODS

From November 2008 to January 2012, 35 patients (29 females and 6 males; mean age 53.9 y) with 39 intracranial aneurysms were treated by FDD. Five patients (14.3%) had ruptured aneurysms and 30 (85.7%) had no previous hemorrhage. The procedures were performed in 5 patients (14.3%) with SILK and in 30 (85.7%) with PED. In 3 patients FDDs were used as a second treatment after failure of previous coiling (2 cases) or stenting (one case). The 39 aneurysms were in supraclinoid ICA in 26 (66.7%), cavernous ICA in 2 (5.1%), PCoA in 4 (10.2%), MCA in 5 (12.9%), SCA in 1 (2.6%) and PICA in 1 (2.6%). The aneurysms were small (<10mm) in 32 cases (82%), large (11-25mm) in 6 (15.3%) and giant in 1 (2.6%). The occlusion rate according to the aneurysm location, size and neck and the complications were evaluated.

RESULTS

Peri-procedural complications included transient dysarthria (2 patients), vasospasm with acute intra-stent aggregation (one), microwire rupture (one) and failure of the stent opening (one). The follow-up was made between 24 and 62 months (mean 41 months); clinical examination and CTA were performed at 1, 3, 6 and 12 months after the procedure. The complete occlusion was confirmed by CTA and DSA. MRI with angiographic-studies was taken every year. Complete occlusion was obtained in 35 aneurysms (92.1%) and subtotal in 3 (7.9%). Complete occlusion occurred at 3 months in 24 cases (68.6%), within 3 and 6 months in 9 (25.7%). The rate and time of complete occlusion were not correlated with the aneurysm size. MCA aneurysms mainly showed partial occlusion (2/3 cases). Besides, large-neck aneurysms and those with a vessel arising from the sac mainly showed late (>6 months) or partial occlusion.

CONCLUSION

FDD are a safe and efficacious treatment of intracranial aneurysms, resulting in high occlusion rate and low incidence of complications. It should be the treatment of choice for the large-neck aneurysm of the ICA.

Enhanced aneurysmal flow diversion using a dynamic push-pull technique: an experimental and modeling study

BACKGROUND AND PURPOSE

Neurovascular flow diverters are flexible, braided stent-meshes for intracranial aneurysm treatment. We applied the dynamic push-pull technique to manipulate the flow-diverter mesh density at the aneurysm orifice to maximize flow diversion. This study investigated the hemodynamic impact of the dynamic push-pull technique on patient-specific aneurysms by using the developed high-fidelity virtual-stenting computational modeling technique combined with computational fluid dynamics.

MATERIALS AND METHODS

We deployed 2 Pipeline Embolization Devices into 2 identical sidewall anterior cerebral artery aneurysm phantoms by using the dynamic push-pull technique with different delivery-wire advancements. We then numerically simulated these deployment processes and validated the simulated mesh geometry. Computational fluid dynamics analysis was performed to evaluate detailed hemodynamic changes by deployed flow diverters in the sidewall aneurysm and a fusiform basilar trunk aneurysm (deployments implemented previously). Images of manipulated flow diverter mesh from sample clinical cases were also evaluated.

RESULTS

The flow diverters deployed in silico accurately replicated in vitro geometries. Increased delivery wire advancement (21 versus 11 mm) by using a dynamic push-pull technique produced a higher mesh compaction at the aneurysm orifice (50% metal coverage versus 36%), which led to more effective aneurysmal inflow reduction (62% versus 50% in the sidewall aneurysm; 57% versus 36% in the fusiform aneurysm). The dynamic push-pull technique also caused relatively lower metal coverage along the parent vessel due to elongation of the flow diverter. High and low mesh compactions were also achieved for 2 real patients by using the dynamic push-pull technique.

CONCLUSIONS

The described dynamic push-pull technique increases metal coverage of pure braided flow diverters over the aneurysm orifice, thereby enhancing the intended flow diversion, while reducing metal coverage along the parent vessel to prevent flow reduction in nearby perforators.

French collaborative group series on giant intracranial aneurysms: Current management

OBJECTIVES

Giant intracranial aneurysms represent a major therapeutic challenge for each surgical team. The aim of our study was to extensively review the French contemporary experience in treating giant intracranial aneurysms in order to assess the current management.

PATIENTS AND METHODS

This retrospective multicenter study concerned consecutive patients treated for giant intracranial aneurysms (2004-2008) in different French university hospitals (Bordeaux, Caen, Clermont-Ferrand, Lille, Lyon, Nice, Paris-Lariboisière, Rouen et Toulouse). Different variables were analyzed: the diagnostic circumstances, the initial clinical status based on the WFNS scale, aneurysmal features and exclusion procedure. At 6 months, the outcome was evaluated according to the modified Rankin Scale (mRS): favorable (mRS 0-2) and unfavorable (mRS 3-6). A multivariate logistic regression model included all the independent variables with P<0.25 in the univariate analysis (P<0.05).

RESULTS

A total of 79 patients with a mean age of 51.5 ± 1.6 years (median: 52 years; range: 16-79) were divided into two groups, with the ruptured group (n=26, 32.9%) significantly younger (P<0.05, Student's-t-test) than the unruptured group (n=53, 67.1%). After SAH, the initial clinical status was good in 12 patients (46.2%), and in the unruptured group, the predominant diagnosis circumstance was a pseudo-tumor syndrome occurring in 22 (41.5%). The first procedure of aneurysm treatment in the global population was endovascular in 42 patients (53.1%), microsurgical in 29 (36.7%) and conservative in 8 (10.2). An immediate neurological deterioration was reported in 38 patients (48.1%) after endovascular treatment in 19 (45.2% of endovascular procedures), after miscrosurgical in 15 (51.7% of microsurgical procedures) and after conservative in 4 (the half). At 6 months, the outcome was favorable in 45 patients (57%) and after multivariate analysis, the predictive factors of favorable outcome after management of giant cerebral aneurysm were the initial good clinical status in cases of SAH (P<0.002), the endovascular treatment (P<0.005), and the absence of neurological deterioration (P<0.006). The endovascular procedure was obtained as a predictive factor because of the low risk efficacy of indirect procedures, in particular a parent vessel occlusion.

CONCLUSION

The overall favorable outcome rate concerned 57% of patients at 6 months despite 53.8% of poor initial clinical status in cases of rupture. The predictive factors for favorable outcome were good clinical status, endovascular treatment and the absence of postoperative neurological deterioration. Endovascular treatment should be integrated into the therapeutic armenmatarium against giant cerebral aneurysms but the durability of exclusion should be taken into account during the multidisciplinary discussion by the neurovascular team.

Patency of the posterior communicating artery after flow diversion treatment of internal carotid artery aneurysms

BACKGROUND AND PURPOSE

Cerebral aneurysm treatment with the Pipeline Embolization Device (PED) often mandates device placement across the ostia of arteries of the Circle of Willis. We determined the patency rates of the posterior communicating artery (Pcomm) after placement across its ostium a PED and studied neurologic outcomes in these patients.

METHODS

We analyzed, retrospectively, a consecutive series of patients in whom a PED was placed across the ostium of Pcomm while treating the target aneurysm. Pcomm arterial flow after PED placement was graded on a 3-point scale at post-operative angiography and follow-up angiography. Data on pretreatment aneurysm rupture status, concomitant coiling, number of PEDs used, and neurologic status at follow-up were collected.

RESULTS

Eleven patients with 13 aneurysms were included in this study. All patients had an ipsilateral posterior cerebral artery arising from the basilar artery (P1). In the immediate post-procedural setting, four patients (36%) had diminished Pcomm flow rates. After a mean follow-up of 12.6±6.7 months, three Pcomm arteries (27%) were occluded and two Pcomm arteries (18%) had diminished flow. Of patients with diminished flow/occluded Pcomm at follow-up, 80% (4/5) had diminished flow at initial post-procedure angiography compared to none of the six patients without diminished/occluded flow immediately post treatment. No patients suffered new neurologic symptoms at follow-up.

CONCLUSIONS

Approximately one half of Pcomm arteries demonstrated occlusion or decreased flow at follow-up if the ostia are covered with a flow diversion device. Covering the Pcomm ostium in patients with a P1 did not result in any neurologic deficits.