Safety and Efficacy of the Neuroform Atlas Stent for Treatment of Intracranial Aneurysms : A Systematic Review and Meta-Analysis

Safety and Efficacy of the Neuroform Atlas Stent for Treatment of Intracranial Aneurysms: A Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND

Intracranial aneurysms (IAs) are the major cause of subarachnoid hemorrhage. Stent-assisted coiling, especially with the Neuroform Atlas stent (NAS), has proved more effective than coiling alone for treating these aneurysms.

PURPOSE

To perform a systematic review and meta-analysis to investigate the efficacy and safety of the NAS in treating IAs.

DATA SOURCES

A comprehensive literature search was conducted on PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and clinicaltrials.gov from inception until June 2024.

STUDY SELECTION

We included studies on ruptured and unruptured IAs treated with the NAS, covering experimental, observational, and case series across all age groups. The aneurysm occlusion rate was assessed by using the Raymond-Roy classification (RROC). The mRS and adverse events related to stent use were also recorded.

DATA ANALYSIS

The statistical analysis was conducted on R Version 4.3.2 by using the packages "meta" and "metasens." We reported our results as proportions with their corresponding CIs. Meta-regression, leave-one-out, and sensitivity analyses were conducted to confirm the robustness of our results.

DATA SYNTHESIS

A total of 42 studies including 2434 participants with a mean age of 51 to 73 years were included. Among angiographic outcomes, the final RROC 1/RROC 2 was achieved in 95% of the patients, final RROC 1 in 82%, RROC 2 in 12%, and RROC 3 in 5% of the patients. Additionally, 93% of the patients showed mRS grade 0, 5% showed mRS grade 1, 3% showed mRS grade 2, 2% showed mRS grade 3, 0% showed mRS grade 4, 0% showed mRS grade 5, and 1% showed mRS grade 6. All adverse events had a ≤5% rate.

LIMITATIONS

Due to limited cause-specific data, we were unable to analyze mortality specific to the stent placement and complications. Despite the large number of studies included, comparative studies were still observed to be scarce.

CONCLUSIONS

Although the generalizability of our findings is limited, this study demonstrates that the NAS is highly effective for treating IAs, with high occlusion rates and a low incidence of adverse events. The stent's performance, supported by comprehensive analysis, highlights its safety and efficacy in managing both ruptured and unruptured aneurysms.

Y Stent-Assisted Coiling Technique for Bifurcation Aneurysms Using Double Neuroform® Stent: a Large Restrospective Series

BACKGROUND

Stent assisted coiling technique have shown to be an effective and safe endovascular strategy for wide neck bifurcation aneurysms in achieving greater packing, allowing the closure of the aneurysm and preserving the parent arteries, compared to simple coiling.

MATERIAL AND METHODS

We conducted a retrospective analysis of 79 patients with cerebral aneurysms treated using 'Y'-configuration double Neuroform® stent-assisted coiling at our center from July 2009 to July 2022.

RESULTS

Of the 79 patients, 76% (60/79) were incidental unruptured cerebral aneurysm and 24% were patients treated for aneurysm recanalization of a previous ruptured aneurysm (19/79). The most frequent locations were anterior communicating artery (AComA) 44.3% (35/79) and middle cerebral artery (MCA) 32.9% (26/79). We found a complete and almost complete aneurysm occlusion (Raymond-Roy occlusion classification (RROC) 1 and 2): in 100% (79/79) in the angiography after procedure, in 97.6% (42/43) at the first follow-up at 6-8 months and 100% (57/57) at the first 1-2 years of follow-up. No mortality related to treatment was detected. We registered 2.5% (2/79) major ipsilateral strokes, one due to acute in stent thrombosis (patient had a mRS: 0 in follow up at 90 days) and a spinal anterior artery occlusion (patient had a mRS: 3 in follow up at 90 days).

CONCLUSION

The 'Y' stent-assisted coiling technique with double Neuroform® is a safe and effective technique for the treatment of wide-neck bifurcation aneurysms, with high rates of complete occlusion, preserving the permeability of the afferent and efferent arteries and low rate of complications.

Single Neuroform Atlas stent: a reliable approach for treating complex wide-neck bifurcated aneurysms

Background

Treating wide-neck bifurcated cerebral aneurysms (WNBAs) using various techniques and new devices has shown favorable outcomes. However, endovascular coiling can be technically challenging when the aneurysm neck is incorporated into the parent vessel. Furthermore, although recent research has reported favorable outcomes of Neuroform Atlas stent (NAS)-assisted coiling, broad inclusion criteria have hampered precise evaluations of their effectiveness and safety for treating complex WNBAs. Therefore, this study evaluated whether the use of a single NAS is a safe and effective approach for treating complex WNBAs.

Methods

We treated 76 complex WNBAs (unruptured, n = 49; ruptured, n = 27) using single NAS-assisted coil embolization and retrospectively analyzed the clinical and angiographic outcomes.

Results

In a cohort of 68 patients (mean age, 58.3 ± 11.6 years; males n = 20, 29.4%; females, n = 48, 70.6%), 76 stents were successfully delivered to the target aneurysms, yielding a technical success rate of 98.6%. Complete occlusion was evident in 59 (77.6%) of 76 aneurysms, with neck remnants found in 16 (21.1%) and partial occlusion in 1 (1.3%). Treatment-related morbidities comprised one branch occlusion and one parenchymal hemorrhage. However, no new neurological symptoms of unruptured aneurysms were evident at discharge. The outcomes of 20 of the 27 ruptured aneurysms were favorable (Glasgow Outcome Scale scores of 4 or 5) at the final follow-up assessment (mean 12.2 [6-29] months), except for one initial subarachnoid hemorrhage. Post-treatment angiography revealed complete occlusion in 89.1%, neck remnants in 7.8%, and incomplete occlusion in 3.1% of the aneurysms. Approximately 88.2% of the patients were assessed at least once by follow-up diagnostic or magnetic resonance angiography (mean, 12.5 ± 4.3 [range, 6-29] months), with five (7.8%) minor and two (3.1%) major recurrences.

Conclusion

A single NAS is safe and effective for treating WNBAs incorporated into parent vessels.

Neuroform atlas stent treatment for 533 intracranial aneurysms in a large Chinese cohort: complication risk factor analysis

BACKGROUND

The newest generation of Neuroform Atlas stent™ (Stryker, Fremont, California) represents a recent advance of cerebral laser-cut microstents for the treatment of intracranial wide-necked aneurysms, and postoperative complications have been observed among Western patients. We assessed predictors of complications, morbidity, and unfavourable outcomes in a large cohort of patients with aneurysms that were treated with Neuroform Atlas stents in China.

METHODS

This retrospective study included subjects who were treated with Atlas stents in China from November 2020 to January 2022.

RESULTS

A total of 522 consecutive patients (mean age, 58.9 ± 9.9 years; female, 65.3% [341/522]) with 533 aneurysms were included in the study. In the early postoperative period, the neurological morbidity rate was 7.3% (38/522), the ischaemic stroke rate was 5.0% (26/522), the aneurysm rupture subarachnoid haemorrhage rate was 2.3% (12/522), and the mRS score deterioration rate was 5.4% (28/522). The mortality rate was 0.8% (4/522) in the postoperative period. The rate of neurological morbidity during the follow-up period was 1.2% (6/486). In the multifactor prediction analysis, cerebral infarction, Hunt-Hess grade (3-5), procedure duration, stent length and coil protrusion into the parent artery were found to be independent predictors of neurologic morbidity. The procedure duration, stent length and coil protrusion into the parent artery were found to be independent predictors of mRS score deterioration.

CONCLUSIONS

The incidence of SCA (stent-assisted coiling)-related complications with the Atlas stent in this study population was comparable to that in Western populations. We identified the procedure duration and stent length as novel independent predictors of SCA-related ischaemic stroke, neurological morbidity, and mRS score deterioration among the Chinese population.

Balloon-Assisted Stent Visualization: A Simple Technique for Precise Measurement of Previously Placed Stent Diameter

Stent-assisted coil embolization is effective for treating intracranial aneurysms, improving outcomes and reducing recurrence rates. However, accurately measuring the diameter of a previously placed stent during imaging can be challenging due to coil artifacts. This poses difficulties in determining the coil packing and size of additional stents needed during retreatment. In a reported case, the use of a balloon enabled precise assessment of stent deployment. A 50-year-old male with a history of basilar artery-left superior cerebellar artery aneurysm underwent coil embolization, direct clipping, and stent-assisted coil embolization (SAC) over a span of 14 years. However, the aneurysm showed reenlargement over time. To address the recurrence, a balloon was used to assess the previously placed Neuroform Atlas stent. Additional coils were inserted outside the stent, and a Low-profile Visualized Intraluminal Support Blue stent was added. Postoperatively, there were no new neurological issues, and a follow-up magnetic resonance imaging showed no ischemic lesions . Balloon-assisted stent visualization (BASV) may be a useful method in the retreatment of SAC. It has the potential to provide valuable information for treatment planning.

A Novel Braided Stent With Customized Simulation Software for Treatment of Intracranial Aneurysms: Multicenter Prospective Trial Before Unrestricted Clinical Application

BACKGROUND AND OBJECTIVES

Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the "premarket" clinical trial of a new braided stent with a customized simulation software.

METHODS

A stent system with 3 mesh density types (16, 24, and 32 wire mesh) was designed based on computational flow dynamics technology, and a simulation software (virtual stent planner [VSP]) was developed for the optimal stent deployment planning. Stents were selected after simulation on preoperative 3D-processed angioimages, and accuracy of the VSP was evaluated.

RESULTS

Thirty-three unruptured intracranial aneurysms were successfully treated with VSP guidance. Twenty aneurysms (61%) were anterior circulation aneurysms, and 13 (39%) were posterior circulation aneurysms. The average aneurysm size was 7.1 mm, and the mean follow-up period was 19.2 months (11-39.0). There was no major recurrence or retreatment during follow-up, 2 morbidity cases, and no mortality. VSP planning presented slightly smaller stent dimensions compared with postdeployment: 24.2 vs 25.5 mm average, error -1.3 mm, and difference rate-5.46%.

CONCLUSION

Based on this result, the new stents and software guidance system were approved by the Ministry of Health and Welfare as a combined medical device. VSP provided precise deployment with minimal error compared with actual stent and can contribute to better stent deployment even for less experienced physicians.

Embolization of unruptured wide-necked aneurysms at the MCA bifurcation using the Neuroform atlas stent-assisted coiling: a two-center retrospective study

Background

The management of middle cerebral artery (MCA) aneurysms remains a controversial topic, and MCA aneurysms have traditionally been treated primarily by surgical clipping. The Neuroform Atlas Stent™ (NAS, available from Stryker Neurovascular, Fremont, California) represents the latest generation of intracranial stents with improved stent delivery system capabilities.

Objective

This study aims to investigate the safety, feasibility and efficacy exhibited by NAS in treating unruptured aneurysms at the MCA bifurcation.

Methods

This was a two-center retrospective study involving 42 patients with unruptured wide-necked aneurysms (WNAs) of the MCA treated with the NAS from October 2020 to July 2022.

Results

The stent was used to treat 42 cases of unruptured WNA at the MCA bifurcation. Endovascular treatment techniques had a 100% success rate. Immediate postoperative angiography found complete aneurysm occlusion in 34 patients (80.9%) (mRRC 1), neck remnant in 7 patients (16.7%) (mRRC 2), and residual aneurysm in 1 patient (2.4%) (mRRC 3). The thromboembolic complication rate was 2.4% (1/42). The follow-up period was 8.7 months on average (3-16 months). The last angiographic follow-up results revealed complete aneurysm occlusion in 39 patients (92.9%) (mRRC 1), neck remnant in 3 (7.1%) patients (mRRC 2), no aneurysm recanalization or recurrence, and no cases of stent intimal hyperplasia. During the latest clinical follow-up, all patients had an mRS score of 0.

Conclusion

Our study demonstrates that the NAS can be applied to treat unruptured WNAs at the MCA bifurcation with favorable safety, feasibility, and efficacy.

A comparison of Atlas and Leo Baby stents-assisted coiling of intracranial aneurysms with small parent vessels

Some studies have reported the efficacy and safety of the Atlas stent and the Leo Baby stent-assisted coiling (SAC) of intracranial aneurysms arising from small cerebral vessels. The authors aimed to compare the clinical performance of the Atlas and the Leo Baby stents in small parent arteries.

METHODS AND MATERIALS

Between January 2019 and November 2022, 56 patients at our centre were treated using either Atlas or Leo Baby SAC of intracranial aneurysms arising from small parent vessels (<2 mm). The clinical and angiographic imaging data of the two cohorts were retrospectively collected and comparatively analyzed.

RESULTS

A total of 56 patients were included in this study. Thirty-two patients were treated with the Atlas SAC, and 24 patients were treated with the Leo Baby SAC. The mean age of the Atlas stent cohort was older, and the mean aneurysm size was smaller than the Leo Baby stent. The immediate complete occlusion rate was 68.6% in the Atlas stent cohort and 62.5% in the Leo Baby stent cohort. The mean angiographic follow-up time for Atlas stent cohort was 8.9±2.5 months, and the final aneurysm complete occlusion rate was 81.0%. The mean follow-up time for Leo Baby stent cohort was 18.9±6.0 months, and the final aneurysm complete occlusion rate was 83.3%.

CONCLUSIONS

At the final follow-up, the Atlas or the Leo baby stent SAC of intracranial aneurysms with small parent vessels resulted in favourable angiographic results and clinical outcomes, with a low rate of associated complications.

Additional rescue stenting with Neuroform Atlas stents during stent-assisted coiling of saccular aneurysms

OBJECTIVE

Overlapping stenting is sometimes attempted during endovascular treatment of cerebral aneurysm as a rescue for coil herniation, stent mal-positioning, or in-stent thrombosis. We retrospectively evaluated the efficacy and safety of additional rescue stenting (ARS) in telescoping fashion with Neuroform Atlas stent (NAS) during stent-assisted coiling of saccular aneurysms.

METHODS

We collected clinical and radiological data of patients with saccular aneurysms treated with ARS using NASs between March 2018 and December 2021. Y or X-stent-assisted coiling technique was excluded.

RESULTS

Eighteen unruptured and 5 ruptured aneurysms in 23 patients were treated with ARS using NASs. Sizes of aneurysms ranged from 2.0 mm to 10.0 mm (mean: 5.0 mm). Immediate angiographic results were complete occlusion in 11 aneurysms, residual neck in 4 aneurysms, and residual sac in 8 aneurysms. Peri-operative morbidity was 4.3 %. Nineteen of 23 patients underwent follow-up conventional angiography (mean, 9.9 months). Results showed progressive occlusion in 10 (52.6 %) cases and asymptomatic in-stent stenosis in 3 (15.8 %) cases. At the end of the observation period (mean, 17.4 months), all 18 patients without subarachnoid hemorrhage had excellent clinical outcomes (mRS of 0), except one (mRS of 1). Of five patients with subarachnoid hemorrhage, four had a favorable outcome (mRS of 0-1), while the other one was dependent (mRS of 4).

CONCLUSION

In this report on 23 patients, ARS with NASs for treating saccular aneurysms showed good technical safety with favorable clinical and angiographic outcomes. However, delayed in-stent stenosis was not uncommon. Thus, regular imaging follow-up is required.

Comparison of Neuroform Atlas Stent-Assisted Coiling and Coiling Alone in Ruptured Intracranial Aneurysms: A Propensity Score Matching Analysis

BACKGROUND

Although Neuroform Atlas stent is commonly used in stent-assisted coiling (SAC) to treat ruptured intracranial aneurysms (RIA), its safety and efficacy remain controversial.

OBJECTIVE

To assess the safety and efficacy of SAC using Neuroform Atlas for treating RIA compared with coiling alone by performing a propensity score matching analysis.

METHODS

RIA treated with coiling alone and SAC between January 2017 and May 2021 were retrospectively reviewed. Demographics, periprocedural complication rates, angiographic outcomes, and clinical outcomes of the SAC using Neuroform Atlas group and the coiling-alone group were analyzed with 1:1 propensity score matching.

RESULTS

A total of 375 aneurysms were enrolled, and 274 (63.1%) aneurysms were treated with coiling alone. In total, 101 (26.9%) aneurysms were treated with SAC, and Neuroform Atlas stent was used in 71 aneurysms. In propensity score matching, the SAC using Neuroform Atlas group showed higher incidence of complete occlusion (69.0% vs 56.3%, P = .029), lower rate of recanalization (11.3% vs 25.4%, P = .011), and lesser need for retreatment (7.0% vs 16.9%, P = .016) compared with the coiling-alone group. However, there were no significant differences in periprocedural complications such as intraprocedural thrombosis or postprocedural cerebral infarct between the 2 groups.

CONCLUSION

The use of Neuroform Atlas is safe and effective for SAC in RIA with comparable procedure-related complication rates but better angiographic outcome in comparison with coiling alone.

Transradial Stent-Assisted Coiling Using "Dual-Jailing" Technique for Kissing Aneurysms of the Internal Carotid Artery: Technical Note and Literature Review

BACKGROUND

Kissing aneurysms are an unusual type of multiple intracranial aneurysms having different origins with partially adherent walls. Although endovascular treatment is a useful alternative to surgical clipping, endovascular management for small wide-necked kissing aneurysms has not been adequately investigated to date. Herein, we present a case of small wide-necked kissing aneurysms successfully treated with transradial stent-assisted coiling (SAC) using the "dual-jailing" technique. We also performed a review of the relevant literature.

CASE PRESENTATION

A 64-year-old woman who was diagnosed with small wide-necked kissing aneurysms relating to the ophthalmic artery underwent SAC using the dual-jailing technique. After a 6F Simmons guiding sheath was delivered into the target common carotid artery via transradial access, a 6F intermediate catheter was navigated into the petrous internal carotid artery to achieve both triple microcatheter manipulation and contrast injection. Two coil-delivery microcatheters were cannulated into each aneurysm, followed by a Neuroform Atlas stent deployment over the aneurysm necks via a third stent-delivery microcatheter. By using the jailed microcatheters, SAC of the kissing aneurysms was successfully achieved, preserving the ophthalmic artery. The postprocedural course was uneventful. A follow-up magnetic resonance angiography showed no evidence of recanalization 2 years 3 months post procedure.

CONCLUSIONS

The dual-jailing technique may provide simple and time-saving SAC compared with previous reported method. This technique can be a useful treatment option for small wide-necked kissing aneurysms.

Application of the Neuroform Atlas Stent in Intracranial Aneurysms: Current Status

The Neuroform Atlas stent (NAS) is the successor of the Neuroform EZ stent. The NAS is compatible with a low-profile 0.0165-inch microcatheter and is soft enough to pass through small and highly tortuous vessels. The NAS can be used in treating intracranial aneurysms at almost all locations, and its use is becoming increasingly common. However, there has not yet been a complete review of NAS applications. Therefore, we performed this review, which addresses several aspects of the NAS, mainly including its characteristics, clinical trials of its application in treating aneurysms, deployment techniques for the device, the prognosis and complications of its application in treating aneurysms, and antiplatelet requirements associated with its use. Based on the evidence reviewed here, as well as our experience, we found that the NAS is a promising device for treating intracranial aneurysms, especially complex and distal aneurysms. This stent can also be used as a powerful tool to assist in rescuing coil migration, completing dual-stent reconstruction, and coiling aneurysms via a transcirculation approach. The device may require antiplatelet therapy at a lower dose and over a shorter period than other stents. The deployment of the NAS to assist in aneurysm coiling can yield good clinical outcomes and an acceptable rate of complications. Thus, the NAS is a promising device.