Stent application for the treatment of cerebral aneurysms

Antegrade horizontal stenting for endovascular coiling of wide-neck aneurysms in the basilar tip: Two case reports

RATIONALE

Endovascular coil embolization for wide-neck intracranial aneurysms is technically challenging and requires supporting devices. Intracranial stents are widely used as a buttress for compact coil filling and preventing coil protrusion into the parent artery. Horizontal stenting has been developed to maximize coil insertion and reduce the risk of thromboembolism. An anterograde route for horizontal stenting could be attempted for basilar tip aneurysms if the posterior communicating artery is not accessible. Here, we report 2 cases of antegrade horizontal stenting (AHS) for wide-neck aneurysm (WNA) in the basilar tip. This approach aims to maximize coil insertion and achieve complete aneurysm occlusion.

PATIENT CONCERNS

Both patients were admitted for the treatment of cerebral aneurysms, which were incidentally detected during routine health checkups.

DIAGNOSES

Both patients were diagnosed with WNAs at the basilar tip and hypoplastic communicating arteries.

INTERVENTIONS

The patients underwent stent-assisted coil embolization for WNA in the basilar tip using the catheter jailing technique. After positioning a pre-jailed microcatheter within a basilar aneurysm, AHS was performed using the Neuroform Atlas stent, with the proximal part of the stent deployed across the neck of the basilar tip aneurysm. In both cases, the preselected microcatheter tip shifted either to the anterior or posterior side of the aneurysm immediately after AHS using the pushing technique. The coils inserted into the aneurysm did not reach the opposite side of the microcatheter placement, necessitating additional catheterization.

OUTCOMES

Complete occlusion was achieved by inserting additional coils through the repositioned microcatheter.

LESSONS

Horizontal stenting via an antegrade route may be an effective strategy for achieving compact coil embolization in selected patients with WNAs at the basilar tip. The Neuroform Atlas stent appears to be a promising tool for AHS owing to its hybrid-cell design. However, the shifting phenomenon of a jailed microcatheter after AHS warrants attention, as it may present potential challenges that require further catheterization.

Safety and efficacy of the novel Alpha stent for the treatment of intracranial wide-necked aneurysm

The Alpha stent is an intracranial closed-cell stent with a unique mesh design to enhance wall apposition. It recently underwent structural modifications to facilitate easier stent deployment. This study aimed to evaluate the safety and efficacy of stent-assisted coil embolization for unruptured intracranial aneurysms using the Alpha stent. Between January 2021 and November 2021, 35 adult patients with 35 unruptured intracranial aneurysms in the distal internal carotid artery were prospectively enrolled. For efficacy outcomes, magnetic resonance angiography at the 6-month follow-up was evaluated using the Raymond-Roy occlusion classification (RROC). The safety outcome evaluated the occurrence of symptomatic procedure-related neurological complications up to 6 months postoperatively. Technical success was achieved in 34/35 (97.1%). Six months postoperatively, aneurysm occlusion showed RROC I in 32/35 (91.4%) and RROC II in 3/35 (8.6%) patients. Procedure-related neurologic complications occurred in one patient (2.9%) who experienced hemiparesis due to acute lacunar infarction, which resulted in a 6-month mRS score of 1. The Alpha stent demonstrated excellent efficacy and safety outcomes in stent-assisted coil embolization of unruptured distal ICA aneurysms. The recent structural modifications allowed for easier stent delivery and deployment.Clinical trial registration number: KCT0005841; registration date: 28/01/2021.

Vascular remodeling in sheep implanted with endovascular neural interface

Objective.The aim of this work was to assess vascular remodeling after the placement of an endovascular neural interface (ENI) in the superior sagittal sinus (SSS) of sheep. We also assessed the efficacy of neural recording using an ENI.Approach.The study used histological analysis to assess the composition of the foreign body response. Micro-CT images were analyzed to assess the profiles of the foreign body response and create a model of a blood vessel. Computational fluid dynamic modeling was performed on a reconstructed blood vessel to evaluate the blood flow within the vessel. Recording of brain activity in sheep was used to evaluate efficacy of neural recordings.Main results.Histological analysis showed accumulated extracellular matrix material in and around the implanted ENI. The extracellular matrix contained numerous macrophages, foreign body giant cells, and new vascular channels lined by endothelium. Image analysis of CT slices demonstrated an uneven narrowing of the SSS lumen proportional to the stent material within the blood vessel. However, the foreign body response did not occlude blood flow. The ENI was able to record epileptiform spiking activity with distinct spike morphologies.Significance. This is the first study to show high-resolution tissue profiles, the histological response to an implanted ENI and blood flow dynamic modeling based on blood vessels implanted with an ENI. The results from this study can be used to guide surgical planning and future ENI designs; stent oversizing parameters to blood vessel diameter should be considered to minimize detrimental vascular remodeling.

Effects of Enterprise 2 stent-assisted coil embolization for wide-necked intracranial aneurysms

BACKGROUND

This study analyzed the safety and efficacy of Enterprise 2 stent-assisted coil embolization for wide-necked intracranial aneurysms by examining stent-vessel apposition, operative complications, embolization outcomes, and clinical outcomes.

METHODS

We retrospectively reviewed the medical records of patients with wide-necked intracranial aneurysms who underwent Enterprise 2 stent-assisted coiling in our hospital from November 2018 to October 2019. Intraoperative VasoCT was performed immediately after stent release in a continuous cohort of patients to observe stent-vessel apposition. Patient demographic, clinical, and imaging data were recorded and analyzed.

RESULTS

A total of 106 wide-necked aneurysms in 106 patients were treated. Stent release was successful in all patients. Twenty-one patients were enrolled consecutively for VasoCT scanning, and incomplete stent apposition was observed in 5 (23.8%). Perioperative complications occurred in 10 patients (9.4%): cerebral infarction in 6, intraoperative coil prolapse in 1, puncture site pseudoaneurysm in 1, deep vein thrombosis at multiple sites in 1, and transient brainstem mass effect in 1. Among the 95 aneurysms with angiographic follow-up, embolization was satisfactory (Raymond-Roy classifications I and II) in 89 (93.7%). Hyperlipidemia was an independent risk factor for incomplete aneurysm occlusion. At the last clinical follow-up, seven patients had a poor clinical outcome (modified Rankin Scale score ≥ 3). Independent risk factors for poor outcomes were preoperative subarachnoid hemorrhage at presentation and cerebral infarction.

CONCLUSION

Enterprise 2 stent-assisted coiling for treatment of wide-necked intracranial aneurysms showed good safety and efficacy; however, incomplete stent apposition can still occur in vessels with a large curvature. Preoperative subarachnoid hemorrhage at presentation and cerebral infarction are the main reasons for poor clinical outcomes after stent-assisted coil embolization.

Delayed Rupture of an Anterior Communicating Artery Pseudoaneurysm Caused by Distal Occlusion Thrombectomy Using a Stent Retriever: A Case Report and Mechanism of Injury

We report a case of delayed rupture of an anterior communicating artery (Acom) pseudoaneurysm following mechanical thrombectomy (MT) of a distal artery occlusion using a stent retriever. An elderly patient with right hemiparesis showed left proximal internal cerebral artery and middle cerebral artery occlusions. During MT, a fragmented thrombus moved to the anterior cerebral artery (ACA). A stent retriever was deployed to the occluded ACA, and the Acom and proximal ACA segment were significantly straightened. Additionally, we attempted a blind exchange mini-pinning (BEMP) technique, but a subarachnoid hemorrhage (SAH) occurred. Bleeding was almost entirely absorbed 9 days after the procedure, but the SAH recurred at 20 days, and computed tomography angiography revealed a new pseudoaneurysm formation in the Acom. We suggest that the proposed mechanism of pseudoaneurysm formation was likely due to the dislocation and avulsion of the Acom perforators when the ipsilateral ACA was pushed and pulled during MT.

Multiple overlapping stent-assisted coiling improves efficacy and safety of treatment for complex intracranial aneurysms: a randomized trial

BACKGROUND

Intracranial aneurysm rupture is the main cause of subarachnoid hemorrhage, leading to high disability and mortality. This study aimed to evaluate the clinical treatment effects of multiple overlapping stent-assisted coiling for complex intracranial aneurysms.

METHODS

We conducted a randomized, controlled, single-blinded clinical trial among 168 patients diagnosed with complex intracranial aneurysms. Treatment allocation to either single stent (SS) group or multiple stent (MS) group was randomized at 1:1 ratio using a Web-based platform. The O'Kelly-Marotta (OKM) grading scale was used to evaluate the degree of aneurysm occlusion after operation and during follow-up. Good aneurysm occlusion was defined as OKM grade C-D. The modified Rankin Scale (mRS) was used to evaluate the neurological status and the clinical outcome of patients.

RESULTS

Efficacy comparative analysis demonstrated that major recurrence of aneurysms was significantly reduced in the MS group (P = 0.012). In addition, the MS group displayed significantly reduced number of patients with mRS between 3 and 6 (P = 0.007) and increased number of patients with mRS between 0 and 1 (P = 0.034). Furthermore, the MS group showed increased percentage of patients with OKM grade C-D (P = 0.041). Compared with the SS group, the MS group exhibited decreased mortality (P = 0.037) and morbidity (P = 0.035).

CONCLUSIONS

Multiple overlapping stent-assisted coiling significantly improved the clinical treatment effects and provided a new method for complex intracranial aneurysms.

Computational Study of Hemodynamic Changes Induced by Overlapping and Compacting of Stents and Flow Diverter in Cerebral Aneurysms

Purpose: The flow diversion effect of an intracranial stent is closely related to its metal coverage rate (MCR). In this study, the flow diversion effects of Enterprise and low-profile visualized intraluminal support (LVIS) stents are compared with those of a Pipeline flow diverter, focusing on the MCR change. Moreover, the changes in the flow diversion effect caused by the additional manipulations of overlapping and compaction are verified using computational fluid dynamics (CFD) analysis. Methods: CFD analysis was performed using virtually generated stents mounted in an idealized aneurysm model. First, the flow diversion effects of single Enterprise, LVIS, and Pipeline devices were analyzed. The Enterprise and LVIS were sequentially overlapped and compared with a Pipeline, to evaluate the effect of stent overlapping. The effect of compacting a stent was evaluated by comparing the flow diversion effects of a single and two compacted LVIS with those of two overlapped, uncompacted LVIS and uncompacted and compacted Pipeline. Quantitative analysis was performed to evaluate the hemodynamic parameters of energy loss, average velocity, and inflow rate. Results: Statistically significant correlations were observed between the reduction rates of the hemodynamic parameters and MCR. The single LVIS without compaction induced a reduction in all the hemodynamic parameters comparable to those of the three overlapped Enterprise. Moreover, the two overlapped, uncompacted LVIS showed a flow diversion effect as large as that induced by the single uncompacted Pipeline. Compacted stents induced a better flow diversion effect than uncompacted stents. The single compacted LVIS induced a flow diversion effect similar to that induced by the two uncompacted LVIS or single uncompacted Pipeline. Conclusions: The MCR of a stent correlates with its flow diversion effect. Overlapping and compaction can increase the MCR of an intracranial stent and achieve a flow diversion effect as large as that observed with a flow diverter.

Comparison of the Physical Characteristics of Support Stents for Cerebral Aneurysm Embolization

Objective

There is a limited understanding of the characteristics of individual intracranial stents used for aneurysm treatment. We used an experimental model to evaluate the physical characteristics of support stents for aneurysm embolization.

Methods

Enterprise 2 VRD 4.0 × 39 mm, Neuroform Atlas 4.5 × 21 mm, and LVIS 4.5 × 32 mm stents were: 1) observed under light microscopy and subjected to measurements of 2) circumferential radial force, 3) strut tension, 4) stent compression, and 5) conformability upon bending.

Results

1) Light microscopy showed a large structural difference between laser-cut (Enterprise 2 VRD, Neuroform Atlas) and braided (LVIS) stents. 2) Within the range of indicated blood vessel diameters, the radial force of Enterprise 2 VRD was higher than that of Neuroform Atlas. An extremely large force was required to decrease the LVIS diameter. 3) Neuroform Atlas easily deformed compared to Enterprise 2 VRD, while LVIS was extended with a smaller traction force than that required for Neuroform Atlas. 4) The compression strength was in the order of Enterprise 2 VRD >Neuroform Atlas >LVIS. 5) Enterprise 2 VRD showed a decreased cell area on the concave side, and Neuroform Atlas showed deformation with overlapping struts on the concave side. LVIS naturally adhered to the wall of the blood vessel model.

Conclusion

Laser-cut and braided stents showed different physical characteristics that were visualized and shown as numerical data. These findings improve the understanding of the proper use of these stents in clinical applications.

Endovascular Treatment of Intracranial Vertebral Artery Dissection

Intracranial vertebral artery dissection (VAD) is the most common arterial dissection in intracranial arteries. Some types of VAD can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis, whereas others can progress to stroke that needs treatment. Recently, endovascular treatment (EVT) has emerged and is suggested as a treatment option for VADs due to perceived low rates of procedure-related morbidity with good efficacy. In the last decade, we have accumulated our strategies to treat those VADs. Here, we try to share our experiences about VADs, including indications and methods of treatment of VADs using EVT. We perform EVT for ruptured VADs presenting with SAH and some of unruptured VADs such as VAD with recurrent or progressive ischemia, dissecting aneurysm larger than 7 mm or with mass effect, early ugly change of VADs in shape and size during follow-up period, involving the basilar artery (BA) and bilateral VADs. We present how we have done in our real practice for the last decade for treating VADs by EVT rather than reviewing and organizing so-far-published literature. We tended to occlude the rupture point by vertebral artery (VA) occlusion in non-dominant VA or stent-assisted coiling in dominant VA for ruptured VADs. We tended to reconstruct original hemodynamics using various stents for unruptured VADs. To decide what to treat and how to treat are very complicated for VADs. However, we believe that EVT is the current mainstay for treating VADs. Each technique of EVT should be determined on a case-by-case basis at the discretion of endovascular neurosurgeons and/or interventional neuroradiologists according to presenting symptoms, hemodynamic status, including sufficiency of the collateral supply and anatomic features of the vertebrobasilar artery as well as the posterior inferior cerebellar artery, anterior spinal artery, and medullary perforators.

Two Patients with Large Aneurysms in Whom Coil Embolization with Overlapping LVIS Stents Was Performed

Objective

We report two patients with unruptured large aneurysms treated by overlapping stent-assisted coil embolization using low-profile visualized intraluminal support (LVIS) stents.

Case Presentation

Case 1: An 80-year-old woman presented with abducens nerve palsy due to an internal carotid artery aneurysm. Case 2: A 75-year-old man presented with a partially thrombosed fusiform aneurysm in the vertebral artery (VA). Both patients were treated by overlapping LVIS stent-assisted coil embolization (overlapping LSACE). Digital subtraction angiography (DSA) a few months after embolization demonstrated complete occlusion of the aneurysm, although immediate angiography revealed dome filling.

Conclusion

Overlapping LSACE may be an effective treatment method for aneurysms that are difficult to treat by standard SACE and result in better flow-diverting effects.

Analysis of branch artery orifice angulation: Feasibility of the shelf technique for the treatment of wide-neck bifurcation aneurysms

BACKGROUND AND PURPOSE

The aim of this study was to investigate the feasibility of the shelf technique by analyzing the angle between the two branch orifices and to present its safety and effectiveness compared with that of the double-stent technique.

MATERIALS AND METHODS

Patients with complex wide-neck bifurcation aneurysms (WNBAs) who underwent stent-assisted coiling (SAC) were reviewed. The study sample was divided into two groups: single SAC (shelf technique) and double SAC. The angle between the lines connecting the superior and inferior points of each branch orifice (α angle) was measured by two neurointerventional radiologists in both groups. The inter- and intraobserver repeatability and consistency of the α angle were assessed. The effect of the α angle on the feasibility of using the shelf technique to treat WNBA was analyzed. Technical and clinical success rates were investigated by comparing both groups.

RESULTS

Forty-eight patients (32 shelf technique and 16 double-stent technique) were included. There was excellent agreement between the intra- and interobserver repeatability and consistency of α angle measurements. The α angle was smaller in the shelf technique group than in the double-SAC group (p < 0.001). The technical and clinical success rates of both groups were similar based on long-term follow-up (p > 0.05).

CONCLUSION

WNBA treatment with the shelf technique is safe and effective. The α angle is a useful parameter to evaluate the performance of the shelf technique. The shelf technique is more suitable for WNBAs with a narrow α angle.

Comparison of Clinical Outcomes After Stent-Assisted Coiling with 3 Types of Self-Expanding Laser-Cut Stents in Patients with Wide-Necked Intracranial Aneurysms

OBJECTIVE

We report the clinical outcomes of stent-assisted coiling for wide-necked intracranial aneurysms using 3 low-profile laser-cut stents and compare the results according to stent type.

METHODS

All patients treated with stent-assisted coiling for their intracranial aneurysms at our hospital between July 2010 and September 2019 were reviewed. We selected patients with Enterprise, Neuroform EZ, or Neuroform Atlas stents who underwent imaging follow-up and investigated aneurysm and stent features, stent-related complications, recanalization, and retreatment rates. We compared the retreatment risk among the patients treated with the 3 stent types using Kaplan-Meier survival analysis and Cox regression analysis.

RESULTS

We evaluated 364 consecutive cases (103 Enterprise, 105 Neuroform EZ, and 156 Neuroform Atlas stents). Neuroform Atlas was more frequently used in distal vessels: 8 (7.8%) Enterprise, 2 (1.9%) Neuroform EZ, and 41 (26.3%) Neuroform Atlas cases, respectively. The median follow-up durations were 6.49, 4.91, and 1.24 years for the Enterprise, Neuroform EZ, and Neuroform Atlas cases, respectively, and retreatment was performed in 11 (10.1%), 9 (8.6%), and 6 (3.8%) cases. In the first 2 years of follow-up, the estimated retreatment risk ratios for Neuroform EZ and Neuroform Atlas with Enterprise as reference were 0.63 (95% confidence interval, 0.24-1.65; P = 0.35) and 0.54 (95% confidence interval, 0.18-1.59; P = 0.26), respectively.

CONCLUSIONS

Neuroform Atlas stents were more frequently deployed in small-caliber vessels compared with the other 2 types of stents. The complication rate and retreatment risk until at least 1 year after the aneurysm treatment appeared to be similar for the 3 stent types.

Early Multicenter Experience With the Neuroform Atlas Stent: Feasibility, Safety, and Efficacy

BACKGROUND

The Neuroform Atlas stent™ (by Stryker, Fremont, California) represents the most recent widely available upgrade to intracranial stenting, providing a laser cut open cell stent with a diameter of 3.0 to 4.5 mm that is delivered through an 0.017-inch microcatheter.

OBJECTIVE

To report our initial multicenter experience of the safety, efficacy, and feasibility of the Atlas stent used for treating aneurysms, as well as one case of intracranial stenosis and one carotid artery dissection as well as other pathologies.

METHODS

A retrospective multicenter study of subjects treated with Atlas stent during the period 2018 to 2019.

RESULTS

The total number of patients included in our analysis was 71 patients. The stent was utilized to treat 69 aneurysm cases. Of the aneurysms, 36% presented with acute rupture and 56% of the ruptured aneurysms were high grade. Mean aneurysm dimension was 7 mm with an average neck width of 4.1 mm. Around 30% had received prior treatment. Telescoping or Y-stent was used in 16% of cases. We did not observe any symptomatic major complications in our series. Asymptomatic major complications were seen in 7 patients (10.1%); technical complications occurred in 4.3%. Immediate modified Raymond-Roy-occlusion-outcome class I/II was observed in 87%, and this increased to 97.7% at latest follow-up, which was at 4 mo; 91.8% of patients achieved favorable clinical outcome, and mortality rate was 1.4%.

CONCLUSION

Our series demonstrates the safety, feasibility, and efficacy of the Atlas stent. The low complication rate and the high obliteration rate managing complex aneurysms, even in an acute ruptured setting, are notable.

Stent-Jack Technique for Ruptured Vertebral Artery Dissecting Aneurysm Involving the Origin of Posterior Inferior Cerebellar Artery

We herein report a case of a ruptured vertebral artery dissecting aneurysm involving the origin of the posterior inferior cerebellar artery that was treated using the stent-jack technique. After parent artery occlusion of the distal vertebral artery, stenting of the posterior inferior cerebellar artery was performed. Further coiling was needed because distal vertebral artery recanalization occurred due to transformation of the coil mass. The stent-jack technique for a ruptured vertebral artery dissecting aneurysm involving the origin of the posterior inferior cerebellar artery is effective; however, careful attention to recanalization after stenting is needed due to transformation of the coil mass.

Visualization of stent apposition after stent-assisted coiling of intracranial aneurysms using high resolution 3D fusion images acquired by C-arm CT

Purpose

We used an imaging technique based on 3-dimensional (3D) C-arm CT to assess the apposition of three types of stents after coiling of intracranial aneurysms.

Methods

All patients with intracranial aneurysms were considered who received stent-assisted coiling with Enterprise2, Neuroform EZ, or Neuroform Atlas stents confirmed by C-arm CT imaging at our institution between June 2015 and November 2017. A 3D digital subtraction angiography (DSA) scan for vessel imaging followed by a high-resolution cone beam CT (HR-CBCT) scan for coil and stent imaging was performed. The images were fused to obtain dual volume 3D fusion images. We investigated malapposition of the stent trunk (crescent sign) and of the stent edges (edge malapposition) and used the χ² statistic to test for an association with stent types. Inter-rater agreement between two raters was estimated using Cohen’s kappa statistics.

Results

We evaluated 75 consecutive cases. Enterprise2 stents were used in 22 cases, Neuroform EZ in 26, and Neuroform Atlas in 27 cases. By stent type, crescent sign was detected in 27% of Enterprise2, 8% of Neuroform EZ, and none of Neuroform Atlas stents (p=0.007), while edge malapposition was detected in 27% of Enterprise2, 58% of Neuroform EZ, and 30% of Neuroform Atlas stents (p=0.05). Excellent (κ=0.81) and good (κ=0.78) agreement between the raters was found for the detection of edge apposition and crescent sign, respectively.

Conclusion

Stent malapposition was clearly visualized by dual volume 3D imaging. The Neuroform Atlas stents showed good apposition even in vessels with strong curvature.

Endovascular reconstructive treatment using a fill-and-tunnel technique for a fusiform vertebral artery dissecting aneurysm with ipsilateral dominance

BACKGROUND

Fusiform dissecting aneurysms involving the dominant vertebral artery with poor collaterals are challenging to treat. The purpose of this study was to present an initial experience with a fill and tunnel technique for reconstructive endovascular treatment of these conditions.

METHODS

A total of 13 patients, 11 men and 2 women, each with a fusiform vertebral artery dissecting aneurysm not amenable to internal trapping of the parent artery, underwent reconstructive endovascular treatment using a fill and tunnel technique between January 2012 and December 2015. The safety, feasibility, and clinical and angiographic outcomes of these procedures were retrospectively evaluated.

RESULTS

The average maximum diameter of the fusiform aneurysms was 12.1 mm. Five were ruptured. Three aneurysms were treated with a single stent and the remaining 10 aneurysms required double-stent placement. Treatment was technically successful in all 13 patients, achieving complete occlusion (n = 10, 76.9%) and near-complete occlusion (n = 3, 23.1%). No procedure-related complications occurred in any patient. There were no delayed thromboembolic or hemorrhagic complications during the follow-up period (mean, 19.0 months). Angiographic follow-ups (mean, 9.1 months) showed stable occlusion in 90.9% (10/11) and asymptomatic in-stent occlusion in one patient (9.1%, 1/11). At the end of the observation period (mean, 19.0 months), all patients had excellent clinical outcomes (modified Rankin Scale (mRS) 0, 92.3%, 12/13), except one (mRS 4), resulting from poor preoperative status.

CONCLUSIONS

This retrospective study demonstrated that endovascular reconstruction using a fill-and-tunnel technique was a technically safe, feasible, and clinically effective treatment method for fusiform vertebral artery dissecting aneurysms with ipsilateral dominance.

Accuracy of Length of Virtual Stents in Treatment of Intracranial Wide-Necked Aneurysms

Background and Purpose

Precise stent deployment is important for successful treatment of intracranial aneurysms by stent-assisted coiling (SAC). We evaluated the accuracy of virtual stents generated using commercial stent planning software by comparing the length of virtual and actually deployed intracranial laser cut stents on three-dimensional digital subtraction angiography (3D-DSA) images.

Methods

We retrospectively analyzed the data of 75 consecutive cases of intracranial wide-necked aneurysms treated with the SAC technique using laser cut stents. Based on 3D-DSA images acquired by C-arm CT, stent sizing and placement were intraoperatively simulated by a commercial software application. The difference in length of the stents was estimated by measuring proximal discrepancies between the end points of the virtual and actually deployed stents on fused pre-procedural and post-procedural 3D-DSA images. Discrepancies between distal stent end points were manually minimized. The Kruskal–Wallis test was applied to test whether stent location, type, and length had an effect on difference in length between virtual and real stent.

Results

The median difference in length between virtual and real stents was 1.58 mm with interquartile range 1.12–2.12 mm. There was no evidence for an effect of stent location (p = 0.23), stent type (p = 0.33), or stent length (p = 0.53) on difference in length between virtual and real stents.

Conclusions

Stent planning software allows 3D simulation of laser cut stents overlain on 3D-DSA images of vessels and may thus be useful for stent selection and deployment of laser cut stents during stent-assisted coiling of intracranial aneurysms.

Stent-Assisted Coil Embolization of MCA Bifurcation Aneurysms at a Hypoplastic M1 Branch by Use of Hook Technique

BACKGROUND

We describe the Hook technique enabling coil embolization in unfavorable M1 bifurcation aneurysms and analyze the morphologic variations in M1 bifurcation to evaluate how often such aneurysms can be seen.

METHODS

Among 42 MCA aneurysms treated by stent-assisted coil embolization, aneurysms arising at the acute-angled hypoplastic M1 branch (n = 14) were treated by the Hook technique, in which a short stent was deployed only to protect the aneurysm neck after microcatheter selection of the hypoplastic M2, followed by subsequent coiling of the aneurysm. Outcome was evaluated, including Raymond classification, coil packing density, final modified Rankin Scale (mRS), and recurrence. Separately, 100 middle cerebral artery (MCA) bifurcation aneurysms were analyzed to assess the proportion of such unfavorable aneurysms.

RESULTS

Procedural success of the Hook technique was obtained in 13 of 14 patients (93%). A mean packing density of 30% was achieved. Magnetic resonance angiographic follow-up at a median 4 months (range, 1-26 months) showed complete occlusion in 11 patients and residual neck filling in 3 patients. There was no clinical event (mRS = 0) over a median 17 months (range, 2-26 months) of clinical follow-up. One patient had a thrombotic occlusion during the procedure, which was resolved after tirofiban infusion, without evidence of an infarct or deficit. Of the 100 MCA bifurcation aneurysms, aneurysm arising in asymmetric hypoplastic M2 division was the most common type (48%).

CONCLUSIONS

The Hook technique enabled stent-assisted coiling of M1 bifurcation aneurysm with extension along the asymmetric hypoplastic M2 division and also securing the M2 branch.

The integration of pharmacology and pathophysiology into locoregional chemotherapy delivery via mass fluid transfer

The prevailing paradigm of locoregional chemotherapy has been centred around delivering chemotherapy as close to the tumour as possible and in some cases incorporating vascular isolation techniques. Strategically, the development of these techniques has been rudimentary without consideration for the interdependencies between macrovascular manipulation and the microvascular effects. This review focuses on how new capabilities offered by recent advances in vascular access technology could be exploited to facilitate the mass fluid transfer (MFT) of anticancer agents to solid tumours. A haemodynamic model of MFT is proposed using the physical laws of fluid flow, flux, and diffusion that describe the microvascular effects anticancer agents may have upon tumours through the manipulation of macrovascular blood flow control. Finally, the possible applications of this technique for several organs are discussed.

Y-configuration stenting for coiling of wide-neck bifurcation aneurysms using Low-profile Visualized Intraluminal Support Junior

Background

Little has been reported about the feasibility and durability of a Low-profile Visualized Intraluminal Support Junior (LVIS Jr) Y-stenting device for wide-neck bifurcation aneurysms.

Purpose

To evaluate the feasibility and durability of LVIS Jr Y-stenting for coiling of unruptured wide-neck bifurcation aneurysms.

Methods

We identified patients in whom LVIS Jr Y-stenting was attempted for unruptured wide-neck bifurcation aneurysms from a prospectively maintained registry of a referral hospital. Procedural success rate, treatment-related morbidity, and clinical and angiographic outcomes were retrospectively assessed.

Results

LVIS Jr Y-stenting was attempted for a total of 21 aneurysms in 21 patients (mean age 60±8.9 years; M:F=6:15): nine basilar artery, six anterior communicating artery, four middle cerebral artery, one internal carotid artery, and one vertebrobasilar fenestration aneurysms. The mean dome and neck size were 7.9±2.7 mm and 5.7±1.8 mm, respectively. All attempts were successful. Treatment-related morbidity occurred in one individual with a modified Rankin Scale (mRS) score of 2. Immediate postprocedural angiograms showed complete occlusion in 15 (71.4%) and neck remnant in 6 (28.6%) patients. All 21 patients had good outcomes (mRS score 0–2) for a mean of 12 months' follow-up (range 6–27 months); mRS score 0 in 20 patients and mRS score 2 in one patient, respectively. Follow-up imaging over a mean of 11 months (range 6–18 months) was available in 18 patients (85.7%). All aneurysms showed complete occlusion at follow-up.

Conclusions

LVIS Jr Y-stenting and coiling for wide-neck bifurcation aneurysms seems to be feasible with acceptable safety and to provide durable aneurysm occlusion for wide-neck bifurcation aneurysms.

Comparative Cost Analysis for the Surgical and Endovascular Treatment of Ruptured Intracranial Aneurysms in Taiwan: A Nationwide Population-Based Cohort Study

OBJECTIVE

Using a database that enabled longitudinal follow-up, we assessed the cost, outcome, complications, and readmission rate of ruptured cerebral aneurysms repaired by surgical clipping and endovascular coiling.

METHODS

This study was a retrospective review of data from a series of patients who underwent surgical clipping or endovascular coiling of ruptured cerebral aneurysms between 1996 and 2013. The medical records and hospital cost data were all examined.

RESULTS

A total of 7690 and 1380 cases were treated with clipping and coiling, respectively. Patients treated with clipping had more comorbidities and were older. The average total cost for endovascular coiling was $13,974.3, whereas the average total cost for surgical clipping was $16,581.7. Perioperative (30-day) mortality was 10.7% in patients with coiled aneurysms, compared with 12.6% in those with clipped aneurysms (P = 0.045). After 1 year of follow-up, clipping was associated with a significantly longer length of hospital stay (P < 0.001) and significantly higher total hospital costs (P < 0.001).

CONCLUSIONS

In Taiwan, the total hospital costs for the surgical clipping of cerebral aneurysms were higher than for endovascular coiling, and the surgical results were associated with significant complications. We suggest that the indications for coiling might need to be expanded from the current standards dictated by the guidelines in Taiwan.

Un-re-sheath-able Misaligned pCONus Device: Case Report of a Unique Complication

pCONus is a stent like endovascular device which aids in retention of coils within wide necked bifurcation aneurysms. It is retrievable even after complete deployment and is detached electrolytically. pCONus aided coiling of wide necked bifurcation aneurysms has a high technical success rate and a good safety profile. Different complications have been described in literature with the usage of pCONus. This case report describes a yet unreported complication of un-re-sheath-ability of a misaligned deployed pCONus device.

Misaligned pCONus Device: Case Report of a Unique Complication

pCONus is a stent-like endovascular device which aids in retention of coils within wide-necked bifurcation aneurysms. It is retrievable even after complete deployment and is detached electrolytically. The pCONus aided coiling of wide-necked bifurcation aneurysms has a high technical success rate and a good safety profile. Different complications have been described in literature with the usage of pCONus. This case report describes a unreported complication of inappropriately deployed pCONus device.

Association of Different Stenting Procedures with Symptomatic Thromboembolic Complications in Stent-Assisted Coiling of Ruptured Wide-Necked Intracranial Aneurysms

OBJECTIVE

This study aimed to evaluate the association of different stenting procedures with the procedure-related complications in stent-assisted coiling (SAC) of ruptured wide-necked aneurysms.

METHODS

Consecutive patients undergoing SAC of ruptured wide-necked aneurysms were retrospectively reviewed between December 2011 and June 2016. They received 1 of the 3 stenting procedures during SAC: 1) the coiling microcatheter was "jailed" outside of the stent and the coil embolization proceeded above the stent; 2) initial stent deployment followed by the coils through the stent's strut technique; or 3) the coil-then-stent technique. The effect of different stenting procedures on clinical complications and outcomes was estimated by logistic regression models.

RESULTS

Of the 93 patients enrolled in this study, 11 of them (11.8%) suffered from symptomatic thromboembolic events and 10 of them (10.8%) had hemorrhagic complications. SAC with different stenting procedures (odds ratio [OR] = 4.10, 95% confidence interval [CI]: 1.20-13.97, P = 0.024) was the only independent risk factor for symptomatic thromboembolic events. The coil-then-stent technique had a higher ischemic complications rate than the other 2 stenting procedures (P = 0.023). Serum glucose (OR = 1.48, P = 0.014) and systolic blood pressure on admission (OR = 0.97, P = 0.046) were independent predictors of hemorrhagic complications during SAC. However, different stenting procedures and stent types were correlated with neither aneurysm occlusion at the end of procedure (P = 0.498 and 0.176, respectively) nor favorable outcome at discharge (P = 0.710 and 0.928, respectively).

CONCLUSION

Different stenting procedures were associated with thromboembolic but not hemorrhagic complications in SAC of ruptured wide-necked aneurysms.

Semi-Jailing Technique Using a Neuroform3 Stent for Coiling of Wide-Necked Intracranial Aneurysms

Objective

The semi-jailing technique (SJT) provides stent-assisted remodeling of the aneurysm neck during coil embolization without grasping the coil delivery microcatheter. We retrospectively evaluated the efficacy and safety of SJT using a Neuroform3 stent for coiling of wide-necked intracranial aneurysms.

Methods

We collected the clinical and radiological data between January 2009 and June 2015 of the wide-necked aneurysms treated with SJT using a Neuroform3 stent.

Results

SJT using a Neuroform3 stent was attempted in 70 wide-necked aneurysms (68 patients). There were 56 unruptured and 14 ruptured aneurysms. The size of aneurysm ranged from 1.7 to 28.1 mm (mean 6.1 mm). The immediate angiographic results were complete occlusion in 55 aneurysms (78.6%), neck remnant in 7 (10.0%), and aneurysm remnant in 8 (11.4%). Overall, periprocedural complications occurred in 13 patients (19.1%), including asymptomatic thromboembolism in 7 (10.3%), symptomatic thromboembolism in 4 (5.9%), and symptomatic hemorrhagic complications in 2 (2.9%). Conventional angiography follow-up was obtained in 55 (78.6%) of 70 aneurysms (mean, 10.9 months). The result showed progressive occlusion in 7 aneurysms (12.7%) and recanalization in 1 aneurysm (1.8%). At the end of the observation period (mean, 17.5 months), all 54 patients without subarachnoid hemorrhage showed excellent clinical outcomes (modified Rankin Scale [mRS] 0), except two (mRS 1 or 2) and seven of 14 patients with subarachnoid hemorrhage remained symptom-free (mRS 0).

Conclusion

In this report of 70 aneurysms, SJT using a Neuroform3 stent for coiling of wide-necked intracranial aneurysms showed good technical safety, as well as favorable clinical and angiographic outcomes.

Bench-top Comparison of Physical Properties of 4 Commercially-Available Self-Expanding Intracranial Stents

PURPOSE

To better understand the performance of four commercially available neurovascular stents in intracranial aneurysm embolization, the stents were compared in terms of their basic morphological and mechanical properties.

MATERIALS AND METHODS

Four different types of stents that are currently being used for cerebral aneurysm embolization were prepared (two stents per type). Two were laser-cut stents (Neuroform and Enterprise) and two were braided from a single nitinol wire (LEO and LVIS stents). All were subjected to quantitative measurements of stent size, pore density, metal coverage, the force needed to load, push, and deploy the stent, radial force on deployment, surface roughness, and corrosion resistance.

RESULTS

Compared to their nominal diameters, all stents had greater diameters after deployment. The length generally decreased after deployment. This was particularly marked in the braided stents. The braided stents also had higher pore densities than the laser-cut stents. Metal coverage was highest in the LEO stent (14%) and lowest in the Enterprise stent (5%). The LIVS stent had the highest microcatheter loading force (81.5 gf). The LEO stent had the highest passage force (55.0 gf) and deployment force (78.9 gf). The LVIS and LEO stents had the highest perpendicular (37.1 gf) and circumferential (178.4 gf) radial forces, respectively. The Enterprise stent had the roughest stent wire, followed by the LVIS, LEO, and Neuroform stents.

CONCLUSION

The four neurovascular stent types differed in terms of morphological and physical characteristics. An understanding of this diversity may help to decide which stent is most suitable for specific clinical situations.

Comparison Between Balloon-Assisted and Stent-Assisted Technique for Treatment of Unruptured Internal Carotid Artery Aneurysms

Purpose

To compare clinical and angiographic outcomes between balloon-assisted (BAC) and stent-assisted coiling for internal carotid artery unruptured aneurysms (ICA-UA).

Materials and Methods

A total of 227 ICA-UA in 190 patients were treated with BAC (120 patients, 141 ICA-UA) or SAC (70 patients, 86 ICA-UA. We compared characteristics of patients and ICA-UA, and clinical and angiographic outcomes between groups.

Results

Aneurysm size and neck diameter were greater for SAC than in BAC, but aneurysm volume and coil packing density were not different between groups. Immediate angiographic occlusion grade was better for BAC than for SAC. Periprocedural thromboembolic events were more frequent during SAC (11.6%) than BAC (2.4%) per aneurysm, but hemorrhagic events were the opposite (2.4% for BAC and none for SAC per aneurysm) (p < 0.05). At discharge, treatment-related morbi-mortality rates were 1.6% for BAC and 1.4% per patient for SAC. At clinical follow-up (BAC, 118 patients [98.3%] for a mean of 48.4 months; SAC, 69 patients [98.6%], for a mean of 37.4 months), 1 additional treatment-related infarction occurred during SAC, resulting in a modified Rankin scale score of 4. Thus, overall treatment-related morbi-mortality rates were 1.7% in BAC and 2.9% in SAC. At imaging follow-up (BAC, 135 aneurysms [95.7%] for 28.3 months; SAC, 81 aneurysms [94.1%] for 23.9 months), BAC and SAC showed stable or improved occlusion in 94.1% and 95.0%, minor recurrence in 4.4% and 2.5%, and major recurrence in 1.5% and 2.5%, respectively.

Conclusion

Both BAC and SAC were safe and effective techniques for ICA-UA. There were no differences in morbi-mortality and recurrence rates between groups.

Easy Advancement of a Large-Profile Microcatheter (Excelsior XT27™) by Parallel Use of Two Microguidewires For Stent Delivery

Purpose

In the endovascular treatment of cerebral aneurysms, navigating a large-bore microcatheter for delivery of an open-cell stent can be challenging, especially in wide-necked bifurcation aneurysms. We were able to overcome this difficulty by parallel use of two microguidewires through the stent-delivery microcatheter.

Materials and Methods

From December 2014 to April 2015, we treated 15 patients with wide-necked bifurcation aneurysms. For stent delivery, we used a 300-cm 0.014-in microguidewire (Transend), which was placed into the target branch using an exchange technique. A 0.027-in microcatheter (Excelsior XT-27), which was designed for the stent, was advanced over the exchange microguidewire. If we had trouble in advancing the microcatheter over the exchange microguidewire, we inserted a regular microguidewire (Traxcess), into the microcatheter lumen in a parallel fashion. We also analyzed the mechanism underlying microcatheter positioning failure and the success rate of the 'parallel-wire technique'.

Results

Among the 15 cases, we faced with navigation difficulty in five patients. In those five cases, we could advance the microcatheter successfully by applying the parallel-wire technique. There were no procedure-related complications.

Conclusion

Simply by using another microguidewire together with pre-existing microguidewire in a parallel fashion, the stent-delivery microcatheter can be easily navigated into the target location in case of any advancement difficulty.

Pipeline Embolization Device for Large/Giant or Fusiform Aneurysms: An Initial Multi-Center Experience in Korea

Purpose

The purpose of this study was to assess the safety and early outcomes of the Pipeline device for large/giant or fusiform aneurysms.

Materials and Methods

The Pipeline was implanted in a total of 45 patients (mean age, 58 years; M:F=10:35) with 47 large/giant or fusiform aneurysms. We retrospectively evaluated the characteristics of the treated aneurysms, the periprocedural events, morbidity and mortality, and the early outcomes after Pipeline implantation.

Results

The aneurysms were located in the internal carotid artery (ICA) cavernous segment (n=25), ICA intradural segment (n=11), vertebrobasilar trunk (n=8), and middle cerebral artery (n=3). Procedure-related events occurred in 18 cases, consisting of incomplete expansion (n=8), shortening-migration (n=5), transient occlusion of a jailed branch (n=3), and in-stent thrombosis (n=2). Treatment-related morbidity occurred in two patients, but without mortality. Both patients had modified Rankin scale (mRS) scores of 2, but had an improved mRS score of 0 at 1-month follow-up. Of the 19 patients presenting with mass effect, 16 improved but three showed no changes in their presenting symptoms. All patients had excellent outcomes (mRS, 0 or 1) during the follow-up period (median, 6 months; range, 2-30 months). Vascular imaging follow-up (n=31, 65.9%; median, 3 months, range, 1-25 months) showed complete or near occlusion of the aneurysm in 24 patients (77.4%) and decreased sac size in seven patients (22.6%).

Conclusion

In this initial multicenter study in Korea, the Pipeline seemed to be safe and effective for large/giant or fusiform aneurysms. However, a learning period may be required to alleviate device-related events.

LVIS Jr 'shelf' technique: an alternative to Y stent-assisted aneurysm coiling

Wide-necked bifurcation intracranial aneurysms have traditionally not been amenable to coil embolization with the use of a single stent due to the high risk of coil prolapse. Y-configuration double stent-assisted coil embolization ('Y-stenting') of this aneurysm type has been shown to have generally good clinical outcomes, although the technique is complex with various challenges described in the literature. The compliant and flexible closed-cell design of braided stents such as the LVIS Jr allows for the creation of a 'shelf' across the aneurysm neck sufficient to prevent coil prolapse. We describe this novel 'shelf' technique and present a small case series of LVIS Jr stent-assisted wide-necked bifurcation intracranial aneurysm coiling in eight patients. Our small, albeit important, case series demonstrates that the 'shelf' technique is feasible and safe with very good short-term clinical and angiographic outcomes, and may obviate the need for Y-stenting.

Clinical and Angiographic Outcomes of Aneurysms Treated with Two Self-expanding Stent-assisted Coiling Systems: A Comparison of Solitaire AB and Enterprise VRD Stents

OBJECTIVE

The purpose of this study was to compare clinical findings and outcomes of Enterprise and Solitaire stent-assisted coiling (SAC).

MATERIALS AND METHODS

Between January 2012 and March 2014, 86 patients (mean age, 60.3 years) harboring 89 aneurysms were treated with Enterprise (n = 57) or Solitaire (n = 32) SAC. The patients' demographics, angiographic results, and clinical outcomes were reviewed retrospectively.

RESULTS

There were no cases of stent navigation, deployment failure, arterial dissection, or intraoperative aneurysmal rupture. Angiographic follow-up imaging was available for 86 (96.6%) aneurysms (Enterprise group, n = 55; Solitaire group, n = 31). Immediate postoperative and follow-up angiographic results showed no flow or only minimal flow into the neck in 83% (Enterprise group, 77.2%; Solitaire group, 93.8%) and 95.3% (Enterprise group, 92.7%; Solitaire group, 100%) of SAC-treated aneurysms, respectively. Both stent groups showed good immediate postoperative and follow-up clinical outcomes. Excepting 2 cases, all patients achieved modified Rankin Scale scores of 0. Coil loop or tail protrusion into the parent artery was observed in 17 (29.8%) and 7 (21.9%) cases in the Enterprise and Solitaire groups, respectively. No statistically significant difference in terms of angiographic results or clinical outcomes was observed between the groups.

CONCLUSION

Excellent and comparable clinical and angiographic outcomes for wide-neck intracranial aneurysms were achieved using both stents. Because of its higher radial strength and better vessel wall apposition, we cautiously propose that the Solitaire stent may be more effective for SAC of aneurysms harboring a large or severe tortuous parent artery.

Combination of Multicatheter Plus Stent or Balloon for Treatment of Complex Aneurysms

BACKGROUND AND PURPOSE

Coiling of complex aneurysms is still difficult even with current adjuvant techniques. This study sought to evaluate the safety and effectiveness of a combination of multicatheter plus stent or balloon for the treatment of complex aneurysms.

MATERIALS AND METHODS

All complex aneurysms that underwent coiling with the combination technique were identified from prospectively maintained neurointerventional data bases. "Complex aneurysm" was defined as a wide-neck aneurysm with branch incorporation into or a deep lobulation of the sac. The clinical and angiographic outcomes were retrospectively analyzed.

RESULTS

Sixty-two complex aneurysms (12 ruptured, 50 unruptured) in 62 patients (mean age, 57 years; male/female ratio, 12:50) were treated with a combination technique by using a multicatheter plus stent (n = 42, 3 ruptured) or balloon (n = 20, 9 ruptured). Treatment-related morbidity (grade 3 hemiparesis) occurred in 1 patient (1.6%). Except for 1 patient who had treatment-related morbidity, none of the other patients with unruptured aneurysms developed new neurologic symptoms at discharge. Nine of the 12 patients with ruptured aneurysms had good outcomes (Glasgow Outcome Score, 4 or 5) at the latest follow-up (mean, 32 months; range, 6-72 months), and 1 patient died from an initial SAH. Posttreatment control angiograms revealed complete occlusion in 27, neck remnant in 34, and incomplete occlusion in 1 aneurysm. At least 1 follow-up catheter or MR angiogram was available in 80.6% (n = 50) (mean, 21 months; range, 6-65 months). There were 4 minor and 3 major recurrences (14.0%).

CONCLUSIONS

In this case series, the combination technique by using multicatheter plus stent or balloon seemed safe and effective for the treatment of complex aneurysms.

Multiple overlapping stent-assisted coiling of complex aneurysms: a single-center experience

OBJECTIVES

Coil embolization of wide-necked and fusiform aneurysms is challenging and is frequently associated with recanalization despite assistance of any additional device. The purpose of this study was to evaluate the feasibility and mid-term outcomes of complex aneurysms after multiple overlapping stent-assisted coiling (OSAC).

METHODS

We retrospectively evaluated 26 wide-necked and fusiform atherosclerotic or dissecting aneurysms that were treated with multiple OSAC. Eight aneurysms (30·8%) presented with subarachnoid hemorrhage and one (3·9%) with intracranial hemorrhage.

RESULTS

Complete embolization was achieved in 15 of the 26 aneurysms (57·7%), while remnant neck was identified in nine (34·6%) and remnant aneurysm was noted in two (7·7%). Immediate procedure-related complications were observed in five patients (19·2%) including two with asymptomatic in-stent thrombosis, one with transient right-sided weakness, one with decreased mentality, and one with aphasia and quadriplegia. A procedure-related permanent neurologic deficit (modified Rankin scale scores of 1 and 5) was noted in two patients (7·7%). Angiographic follow-up (mean duration 23·9 months) after OSAC was carried out in 18 patients (69·2%): 11 (61·1%) were stable, 3 (16·7%) improved, 3 (16·7%) had minor compaction, and 1 had major recanalization (5·5%). One recurred aneurysm after OSAC and two recanalized aneurysms after single stenting were re-treated using additional stent-assisted coiling, and there was no recanalization in these three aneurysms during the 25·7 months after re-treatment.

CONCLUSIONS

Multiple OSAC is feasible and effective for complex aneurysms and recurrent aneurysms after stent-assisted coiling.

Temporary stent scaffolding during aneurysm coiling

We report a case of temporary Solitaire FR stent (Covidien, Mansfield, MA, USA) scaffolding to reduce coil herniation during embolization of a large neck anterior communicating artery aneurysm. In contrast to classic stent-assisted coiling, the fully retrievable stent is recaptured prior to detachment of the last coil. The presented technical nuance hence does not require institution of prolonged antiplatelet coverage. But the door is left open for coil-repositioning in case of coil basket instability. Permanent stent redeployment remains a fall-back option if critical hardware conflict occurs. In comparison to classic balloon remodeling, the presented method may offer easier distal access, particularly in tortuous arterial anatomy. Temporary occlusion of the parent artery, side branches, and perforators is also avoided. Given its specific potential advantages, temporary stent scaffolding using the fully retrievable Solitaire FR device may find its niche as a bailout option, primarily in a very specific subset of distally located wide neck aneurysms.

Initial experience with the new double-lumen scepter balloon catheter for treatment of wide-necked aneurysms

Objective

A new double-lumen balloon catheter was being developed for the treatment of cerebral aneurysms. The purpose of this study is to report our initial experience of a double-lumen balloon catheter for the treatment of wide-necked aneurysms.

Materials and Methods

Seventeen patients (mean age, 63 years; range, 45-80 years) with wide-necked, with or without a branch-incorporated aneurysms, (10 ruptured and 9 unruptured) were treated with balloon-assisted coil embolization using a double-lumen balloon catheter (Scepter C™ or Scepter XC™) for 7 months after being introduced to our country. Locations of the aneurysms were posterior communicating artery (n = 7), anterior communicating artery or A2 (n = 7), middle cerebral artery (MCA) bifurcation (n = 3), basilar artery tip (n = 1) and anterior choroidal artery (n = 1). The initial clinical and angiographic outcomes were retrospectively evaluated.

Results

Coil embolization was successfully completed in all 19 aneurysms, resulting in complete occlusions (n = 18) or residual neck (n = 1). In one procedure, a thrombus formation was detected at the neck portion of the ruptured MCA bifurcation aneurysm near to the end of the procedure. It was completely resolved with an intra-arterial infusion of Glycoprotein IIb/IIIa inhibitor (Tirofiban, 1.0 mg) without any clinical sequela. There were no treatment-related events in the remaining 18 aneurysms. At discharge, functional neurological state improved in 11 patients (10 patients with ruptured aneurysm and 1 with unruptured aneurysm presenting with mass symptoms) and 6 patients with unruptured aneurysms had no newly developed symptoms.

Conclusion

In this preliminary case series, the newly developed double-lumen Scepter balloon appears to be a safe and convenient device for coil embolization of wide-necked aneurysms.

Treatment of rabbit carotid aneurysms by hybrid stents (microporous thin polyurethane-covered stents): preservation of side-branches

Objective

We sought to determine the patency of normal arterial branches from the covered segments of an artery after stenting.

Background

Most intracranial aneurysms occur at arterial branching points (bifurcations, side-branches, or perforators). The post-stenting patency of normal arterial branches from the covered segments of the artery is important. We have previously developed a hybrid stent with micropores to prevent early parent artery occlusion by more early endothelialization, and mid- to long-term parent artery stenosis by control of intimal hyperplasia after aneurysm occlusion.

Methods

We created aneurysms in 10 rabbits by distal ligation and intraluminal incubation of elastase within an endovascularly trapped proximal segment of the common carotid artery. All animals were treated with hybrid stents having micropores. Four animals were observed for one month and three each for three and 12 months. The patency of the side-branches of the subclavian artery was evaluated angiographically and in some cases, histologically.

Results

Aneurysms were completely occluded at all time points other than 12 months. The subclavian artery and brachiocephalic artery were patent, without significant stenosis. All the side-branches of the subclavian artery detected on the preoperative angiogram remained patent at the final assessment.

Conclusion

The use of hybrid stents for aneurysm repair and side-branch patency seems to be effective, as per the long-term results obtained in an animal model.

Geometry of saccular cerebral aneurysms not associated with a branch vessel

OBJECTIVE

Saccular cerebral aneurysms located at nonbranching sites are uncommon. Their distribution, morphological features, and presence of a branch vessel or a tiny perforator(s) separate from the aneurysm neck were investigated.

METHODS

From a series of 303 microsurgically clipped saccular cerebral aneurysms, 40 aneurysms were identified at sites not related to a branch vessel.

RESULTS

The distribution of aneurysms at nonbranching sites was internal carotid: 21 of 40 (52.5%); main stem of the middle cerebral artery/secondary branch of the middle cerebral artery: 6 of 40 (15%); anterior cerebral artery: 1 of 40 (2.5%); pericallosal artery: 1 of 40 (2.5%); pericallosal/callosal marginal: 3 of 40 (7.5%); vertebral artery: 1 of 40 (2.5%); posterior cerebral artery: 1 of 40 (2.5%); posterior cerebral artery/secondary branch of the posterior cerebral artery: 1 of 40 (2.5%); anterior inferior cerebellar artery: 1 of 40 (2.5%); and distal posterior inferior cerebellar artery: 1 of 40 (2.5%). Branch vessels were seen in 5 cases, and small perforating vessels were observed in 2 instances.

CONCLUSIONS

Saccular aneurysms occurring at nonbranching sites are uncommon. Their geometry is particularly favorable for flow directed stents and is most amenable to aneurysms located on large-diameter conducting vessels such as the internal carotid, vertebral, and vertebrobasilar vessels. Smaller parent arteries harboring this type of aneurysm will require new technology to maintain patency of these more distal vessels. If endovascular techniques cannot achieve aneurysm sac obliteration, then open craniotomy and aneurysm clipping will provide a satisfactory alternative.

Stent-assisted coiling of intracranial aneurysms: predictors of complications, recanalization, and outcome in 508 cases

BACKGROUND AND PURPOSE

Self-expanding stents are increasingly used for treatment of complex intracranial aneurysms. We assess the safety and the efficacy of intracranial stenting and determine predictors of treatment outcomes.

METHODS

A total of 508 patients with 552 aneurysms were treated with Neuroform and Enterprise stents between 2006 and 2011 at our institution. A multivariate analysis was conducted to identify predictors of complications, recanalization, and outcome.

RESULTS

Of 508 patients, 461 (91%) were treated electively and 47 (9%) in the setting of subarachnoid hemorrhage. Complications occurred in 6.8% of patients. In multivariate analysis, subarachnoid hemorrhage, delivery of coils before stent placement, and carotid terminus/middle cerebral artery aneurysm locations were independent predictors of procedural complications. Angiographic follow-up was available for 87% of patients at a mean of 26 months. The rates of recanalization and retreatment were, respectively, 12% and 6.4%. Older age, previously coiled aneurysms, larger aneurysms, incompletely occluded aneurysms, Neuroform stent, and aneurysm location were predictors of recanalization. Favorable outcomes were seen in 99% of elective patients and 51% of subarachnoid hemorrhage patients. Patient age, ruptured aneurysms, and procedural complications were predictors of outcome.

CONCLUSIONS

Stent-assisted coiling of intracranial aneurysms is safe, effective, and provides durable aneurysm closure. Higher complication rates and worse outcomes are associated with treatment of ruptured aneurysms. Stent delivery before coil deployment reduces the risk of procedural complications. Staging the procedure may not improve procedural safety. Closed-cell stents are associated with significantly lower recanalization rates.

Safety and efficacy of endovascular treatment of basilar tip aneurysms by coiling with and without stent assistance: a review of 235 cases

BACKGROUND

Endovascular therapy is now the preferred treatment option for basilar tip aneurysms (BTAs).

OBJECTIVE

To compare the safety and efficacy of common endovascular techniques in the treatment of BTAs.

METHODS

A retrospective review was conducted of 235 patients with BTAs treated with endovascular means in our institution between 2004 and 2011. Categorization was based on the presence and type of stent assistance (none, single, and Y stenting). The rates of perioperative complications, recanalization, rehemorrhage, and retreatment were analyzed.

RESULTS

A total of 147 patients were treated with coil embolization and 88 patients with stent-assisted coiling (72 single stents, 16 Y stents). Thromboembolic complications occurred in 6.8% of patients in both groups. There was no associated mortality. Angiographic follow-up (mean, 23.5 months) was available in 172 patients (77.1%). Stented patients had significantly lower recanalization (17.2% vs 38.9%; P=.003) and retreatment (7.8% vs 27.8%; P=.002) rates compared with nonstented patients. Four rehemorrhages (2.7%) occurred in the coiled group, whereas none were noted in the stented group (P=.3). In paired comparisons, lower recanalization (8.3% vs 19.2%; P=.21) and retreatment (0% vs 9.6%; P=.19) rates were seen in the Y-stent group compared with the single-stent group. Thromboembolic complications occurred in 6.9% and 6.2% of patients in the single-stent and Y-stent groups, respectively (P=.91). In multivariate analysis, larger aneurysms, nonstented aneurysms, incomplete initial occlusion, and subarachnoid hemorrhage were predictors of aneurysm recanalization.

CONCLUSION

Stent-assisted coiling has significantly lower recurrence, retreatment, and rehemorrhage rates than coiling alone for the treatment of BTAs. Y stenting has the highest efficacy with low complication rates.