The low-profile Neuroform Atlas stent in the treatment of wide-necked intracranial aneurysms – immediate and midterm results: An Italian multicenter registry

Pipeline embolization device versus Atlas stent assisted coiling for intracranial aneurysm treatment: a retrospective, propensity score matched study with a focus on midterm outcomes and hospital costs

BACKGROUND

Stent assisted coiling (SAC) and flow diverters (FDs) are common endovascular treatments for wide necked cerebral aneurysms, but studies comparing the new generation Atlas SAC and FDs are scarce. We performed a propensity score matched (PSM) cohort study to compare the Atlas SAC and the pipeline embolization device (PED) for proximal internal carotid artery (ICA) aneurysms.

METHODS

Consecutive ICA aneurysms treated at our institution with either the Atlas SAC or PED were studied. PSM was used to control for age, sex, smoking, hypertension, and hyperlipidemia, and the rupture status, maximal diameter, and neck size of the aneurysm (aneurysms >15 mm and non-saccular aneurysms were excluded). Midterm outcomes and hospital costs were compared between these two devices.

RESULTS

A total of 309 patients with 316 ICA aneurysms were included. Following PSM, 178 aneurysms treated with the Atlas SAC and PED were matched (n=89 in each group). Aneurysms treated with the Atlas SAC required a slightly longer procedure time, but had lower hospital costs than those treated with the PED (115.2±24.6 vs 102.4±40.8 min, P=0.012; $27 650.2±$6961.4 vs $34 107.0±$3707.2, P<0.001). Atlas SAC and PED treatments showed equivalent aneurysm occlusion rates (89.9% vs 86.5%, P=0.486), complication rates (5.6% vs 11.2%, P=0.177), and a favorable functional outcome (96.6% vs 97.8%, P=1.0) at follow-up (8.2±3.0 vs 8.4±4.2 months, P=0.652).

CONCLUSION

In this PSM study, midterm outcomes of the PED and Atlas SAC in the treatment of ICA aneurysms were similar. However, SAC required a longer operation time, and the PED may increase the economic cost of inpatients in Beijing, China.

Use of the Neuroform Atlas stent for wide-necked cerebral aneurysms

To investigate the effect and safety of the Neuroform Atlas (NFA) stent in stent-assisted coiling of wide-necked intracranial aneurysms, patients with wide-necked intracranial aneurysms were retrospectively enrolled and treated with the NFA stent-assisted coiling. The modified Rankin scale (mRS) grades and Raymond grades were used to assess the clinical outcomes and aneurysm occlusion degrees, respectively, after embolization and at follow-up. Totally, 122 patients were enrolled with 129 wide-necked aneurysms, and forty-nine (40.2%) patients experienced subarachnoid hemorrhage. A total of 134 NFA stents were deployed in all patients. Immediately after endovascular embolization, the Raymond grade was I in 112 (86.8%), II in 8 (6.2%), and III in 9 (7.0%). Complications occurred in 7 (5.7%) patients, including stent displacement in 2 (1.6%) patients, thrombosis and cerebral infarction in 4 (3.3%), and death in 1 (0.8%). Clinical follow-up was performed in 113 (92.6%) patients 6-30 (mean 21) months after embolization, with the mRS grade 0 in 99 (87.6%) patients, 1 in 7 (6.2%), 2 in 5 (4.4%), and 3 in 2 (1.8%). Good prognosis (mRS ≤ 2) was achieved in 111 (98.2%) patients while poor prognosis (mRS > 2) in two (1.8%). Digital subtraction angiography was conducted in 98 (80.3%) patients with 104 (80.6%) aneurysms 6-30 (mean 21) months after embolization. The Raymond grade was grade I in 94 (90.4%) aneurysms, II in 4 (3.8%), and III in 6 (5.8%). Compared with the Raymond grades immediately after embolization, 93 (89.4%) aneurysms disappeared, 9 (8.7%) remained unchanged in the occlusion status, and 2 (1.9%) were recurrent. In conclusion, the NFA stent may have a high aneurysm occlusion rate and a low complication rate in assisting coiling of wide-necked intracranial aneurysms even though further studies are necessary to prove this.

Stretched and fractured Neuroform Atlas® stent during a stent‑assisted coil embolization: A case report

The Neuroform Atlas^® stent is one of the most recently developed stents for coil embolization, with advancements in a lower-profile delivery system, enhanced trackability, smaller cell size, and increased wall conformability. Because of these advantages, the Neuroform Atlas^® stent shows high technical success with few procedure-related complications. However, the present study reported a rare complication of a stretched and partially fractured Neuroform Atlas^® stent due to unexpected partial withdrawal of microcatheter during deployment for coil embolization of an intracranial aneurysm. The measured length of the stent was ~30 mm, which was greater than the normal length (21 mm). An additional stent was inserted into the distal part of the deployed stent to stabilize the damaged stent and remodel the aneurysm neck. This complication was considered to potentially result from the combination of several factors, including: Curved vessel; open-cell stent; unexpected microcatheter withdrawal during stent deployment; and hooking of the aneurysm selecting microcatheter with stent strut. Understanding the stent design and careful manipulation while avoiding unexpected withdrawal of the microcatheter could prevent this complication.

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.

Neuroform atlas stent-assisted coiling of tiny wide-necked intracranial aneurysms

Objective

To investigate the safety and efficacy of Neuroform Atlas stent-assisted coiling for the treatment of tiny wide-necked intracranial aneurysms and evaluate risk factors associated with procedure-related complications.

Methods

We retrospectively examined 46 patients with 46 tiny wide-necked aneurysms who were treated using Atlas stent-assisted coiling at our institution from August 2020 to May 2022. Patient and aneurysm characteristics, procedural details, procedure-related complications, and angiographic and clinical outcomes were analyzed.

Results

A total of 10 patients presented with aneurysmal rupture. Atlas stent placement was successful in all patients. Angiography immediately after the procedure showed complete occlusion in 38 patients (82.6%), neck remnant in 7 (15.2%), and partial occlusion in 1 (2.2%). The mean angiographic follow-up was 8.4 months (range, 6–16). At the last follow-up, angiography showed complete occlusion in 41 patients (89.1%) and neck remnant in 5 (10.9%). No aneurysm recurrence or in-stent stenosis occurred. Incidence of procedure-related complications was 10.8% (intraprocedural aneurysm rupture, two cases; acute thrombosis, two cases; and coil migration, one case); only one patient (2.2%) experienced procedural neurological morbidity. The mean clinical follow-up was 9.7 months. A favorable outcome was achieved in 45 patients (97.8%). In univariate logistic regression analysis, aneurysm size (odds ratio, 4.538; P = 0.045) was significantly associated with procedure-related complications. However, multivariate analysis found no independent risk factors.

Conclusion

Atlas stent-assisted coiling of tiny wide-necked intracranial aneurysms is feasible and effective. Outcomes and occlusion rates are favorable and morbidity is low. The complication rate may be higher in larger tiny aneurysms.

Stent-assisted coiling using the Neuroform Atlas stent for treatment of aneurysms that recur after coil embolization

Objective

To evaluate the safety and efficacy of stent-assisted coiling (SAC) using the Neuroform Atlas stent for aneurysms that recur after coil embolization.

Methods

We retrospectively reviewed patients who underwent SAC using the Neuroform Atlas stent to treat aneurysms that recurred after coil embolization from November 2020 to November 2021. Patient and aneurysm characteristics, procedural details, complications, and angiographic and clinical follow-up outcomes were recorded and analyzed.

Results

Eleven patients with 11 recurrent aneurysms were included for analysis. Atlas stent deployment was successful in all cases. Angiography immediately after the SAC procedure and at last follow-up showed complete occlusion in 10 patients (90.9%) and a residual neck in one (9.1%). Mean angiographic and clinical follow-ups were 9.2 and 10 months, respectively. A single procedure-related complication occurred, mildly blurred vision in the left eye, which recovered completely. No permanent morbidity or mortality occurred.

Conclusion

SAC using the Atlas stent to treat aneurysms that recur after coil embolization is safe and effective. Large-scale studies with long-term follow-up are warranted to confirm our results.

Application of Third Molar Maturity Index (I3M) for Assessing Adult Age of 18 Years in a Southern Italian Population Sample

OBJECTIVE

 Age estimation of living or dead individuals has a strategic importance in medicine, anthropology, and forensic science, in the context of mass disasters and in civil or criminal matters such as adoption or asylum. Teeth play a major role in this context in particular, the third molars are useful for determining whether an individual has reached the legal age of 18 years because they are still in development from the age of 14.

MATERIALS AND METHODS

 In this study, a sample of 307 panoramic radiographs performed on healthy subjects aged between 13 and 23 was analyzed to consider the correlation between the maturity index of the third molar (I3M) and age to verify the reliability of the cutoff 0.08 indicated by Cameriere et al in a sample of Italian subjects living in the Province of Messina (Sicily, South Italy) to discern the adult subjects from the minors.

STATISTICAL ANALYSIS

 The analysis of 307 panoramic radiographs resulted in a sensitivity of 89.2% with a confidence interval of 95%, a specificity of 96.5% with a confidence interval of 95%, and a positive predictive value of 96.7%.

RESULTS

 The method proved itself reliable in estimating adulthood in the population of the Messina- Sicily, but the I3M should not be used as the sole indicator to determine whether a person is younger or older than 18 years because age estimation based on dental methods alone has limitations as the third molars suffer from many variations related to their morphology, their location, and their development.

CONCLUSION

 We recommend a combination of several methods that are available to increase accuracy of age estimation, depending on the different legal requirements in civil or criminal cases.

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.

Coil Embolization of Unruptured Cerebral Aneurysms Using Stents in Small Arteries Less Than 2 mm in Diameter

BACKGROUND

Data regarding the safety and effectiveness of stent placement in small vessels (<2 mm in diameter) for treating wide-necked cerebral aneurysms are limited.

OBJECTIVE

To report our experience regarding coil embolization of unruptured cerebral aneurysms using stents (specifically the Neuroform Atlas) in small arteries <2 mm in diameter.

METHODS

Patients with unruptured cerebral aneurysms treated with stent-assisted coil embolization between March 2017 and March 2021 in our hospital were included.

RESULTS

Of the 137 cerebral aneurysms included in this study, 49 required stent placement and 48 were treated using the Neuroform Atlas in the small vessels measuring <2 mm in diameter (small vessel group [SVG]). In the SVG, 43 aneurysms (87.8%) demonstrated complete occlusion. Regarding complications, 2 (4.1%) patients had in-stent thrombosis during procedures and 5 (10.2%) experienced symptomatic thromboembolic complications, but only 2 (4.1%) had worsening of the modified Rankin scale ≥1 at 90 days after embolization. Patients with middle cerebral artery aneurysms had a higher risk of thrombotic events (5/18 patients, 27.8%), such as symptomatic thromboembolic complications or intraprocedural in-stent thrombus than those with other aneurysms (1/31 patients, 3.2%), in the SVG (P = .0167).

CONCLUSION

Stent-assisted coil embolization for unruptured cerebral aneurysms using stents, especially the Neuroform Atlas, in small arteries <2 mm in diameter is effective and feasible, but careful perioperative attention should be given to thrombotic events during the embolization of middle cerebral artery aneurysms.

Transradial quadraxial system for coil embolization of distal anterior cerebral artery aneurysms: A radial-first center case series and literature review

PURPOSE

Endovascular treatment is technically challenging as distal anterior cerebral artery (DACA) aneurysms have distal location, small-caliber parent artery, and small size/wide neck. This study evaluated the feasibility and safety of the transradial approach (TRA) with a radial-specific neurointerventional guiding sheath as the first-line technique for DACA aneurysms.

METHODS

We retrospectively analyzed an institutional database of consecutive patients with DACA aneurysm who underwent coil embolization using TRA. Ten consecutive patients were included in this study. After the radial-specific 6F Simmons guiding sheath (0.088″ inner diameter) was completely engaged into the target common carotid artery, a quadraxial system (6F Simmons guiding sheath/6F intermediate catheter/3.2F intermediate catheter/single microcatheter) was used for embolization. Then, we assessed for procedural success, angiographic outcomes, and procedure-related or vascular access site complications.

RESULTS

Embolization procedures were conducted using simple coiling in eight and stent-assisted coiling with the trans-cell approach in two patients. The embolization procedure was successful in all patients (n = 10). Moreover, none presented with catheter kinking, parent artery flow stagnation, or system instability during the procedure. Immediate postprocedural angiography revealed complete obliteration in six and residual neck in four patients. Then, eight patients underwent follow-up angiography at a mean of 7.1 months, and none developed recanalization or required retreatment. The postprocedural course was uneventful, and there were no complications.

CONCLUSION

The transradial quadraxial system had the ability to achieve sufficient stability and kink resistance in DACA aneurysm embolization. Thus, this method was feasible and safe and had a high success rate.

Safety and effect of Neuroform Atlas stent in the treatment of symptomatic intracranial stenosis: A single-center experience

Background

Vascular intracranial stenosis (IS) is a significant cause of acute ischemic stroke (AIS). This single-center study aims to show that symptomatic IS treatment by using the Neuroform Atlas stent (Stryker neurovascular, Kalamazoo, MI, USA) could be effective in reducing vessel stenosis.

Methods

Ten patients affected by AIS or TIA, in the vascular territory of high-grade intracranial atherosclerotic lesions (>70% of vessel stenosis), older than 18-year-old, were treated by implanting a Neuroform Atlas stent (diameter of 4.5mm in 80% and 4mm in 20%). 70% of the patients underwent pre-stenting intracranial angioplasty.

Results

Patients were between 54.8 and 83 years old (mean 68.46y ± 8.44y), 70% males and 30% females. At admission, 50% of all patients had an AIS and 50% a TIA. Restoration of the stenotic lumen was obtained after the endovascular procedure. The percentage mean of vascular stenosis was 83.7% ± 6.09% before treatment (t0), 52.2% ± 10.42% at the end of treatment (t1) and 46.2% ± 8.28% at the follow-up (t2). The IS percentage mean reduction between t0 and t1 was 31.5% ± 7.31%, and between t1 and t2 was 6% ± 5.47%, t0 and t2 of 37.5% ± 7.38%. Percentage reduction of IS was highly significant between time t0 and t1 (p = 0.005), and t0 and t2 (p = 0.005), also with a significant reduction between t1 and t2 (p = 0.012). No patient had experienced an increase of the ischemic area in the vascular territory of the target vessel at 3 months from the initial assessment. 10% of patients experienced a 3-months negative outcome (mRS = 5), 90% experienced a favorable outcome (mRS ≤2).

Conclusions

Intracranial stenosis endovascular treatment with Neuroform Atlas stent provides encouraging results, with a statistically significant association between the vascular caliber improvement and the endovascular treatment.

Multi-centric European post-market follow-up study of the Neuroform Atlas Stent System: primary results

BACKGROUND

Few prospective series have described the safety and effectiveness of the Neuroform Atlas Stent System. We aimed to investigate the efficacy and safety of the device in patients treated for unruptured aneurysm.

METHODS

ATLAS EU PMCF is a consecutive, prospective, multicentric study that included patients with unruptured saccular aneurysm of all sizes. Follow-up visits were scheduled at 3-6 months and 12-16 months with digital subtraction angiography (DSA) or MRI imaging follow-up as per the site standard of care. The primary efficacy endpoint was adequate aneurysm occlusion (Raymond Roy occlusion grade I and II) on 12 month angiography. The primary safety endpoint was any major stroke or ipsilateral stroke or neurological death within 12 months.

RESULTS

Of the 106 patients consented, 105 were treated with at least one Neuroform Atlas stent. There was a failed implantation attempt in 1 patient, 85 patients received lateral stenting, and 19 patients received Y-stenting. Mean aneurysm neck size was 4.2 mm (range 1.9-33 mm). Adequate occlusion was observed in 95.1% immediately after the procedure and in 98.9% of cases at 1 year DSA follow-up. Overall, 1.0% (1/102; 95% CI 0.0% to 5.3%) of patients experienced a primary safety endpoint of major stroke. Three minor strokes resulted in a modified Rankin Scale score of 2.

CONCLUSIONS

In this multicentric, prospective study, stent-assisted coiling of medium size unruptured aneurysms with the Neuroform Atlas stent resulted in a favorable rate of satisfactory occlusion. In our findings, the use of the Y-stenting technique was associated with increased rates of procedural complications.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02783339.

Clinical and Angiographic Outcomes After Stent-Assisted Coiling of Cerebral Aneurysms With Laser-Cut and Braided Stents: A Comparative Analysis of the Literatures

Introduction: Stent-assisted coiling (SAC) plays an important role in endovascular treatment of intracranial aneurysms (IAs). This comparative analysis examines the safety and efficacy of SAC in general and compares clinical and angiographic outcomes between laser-cut stents and braided stents.

Methods: Relevant English-language studies were identified via a PubMed search for published articles regarding outcomes of SAC using laser-cut stents and braided stents published from 2015 to 2020. Data from 56 studies that met our inclusion criteria were pooled and statistically compared.

Results: A total of 4,373 patients harboring with 4,540 IAs were included. Patients were divided into two groups on the basis of stent type: laser-cut stents (2,076 aneurysms in 1991 patients; mean follow-up, 12.99 months) and braided stents (2,464 aneurysms in 2382 patients; mean follow-up, 18.41 months). Overall, the rates of successful stent deployment, thromboembolic events, stent stenosis, periprocedural intracranial hemorrhage, permanent morbidity, mortality, and recanalization were 97.72, 4.72, 2.87, 1.51, 2.14, 1.16, and 6.06%, respectively. Laser-cut stents were associated with a significantly higher rate of successful deployment (p = 0.003) and significantly lower rate of periprocedural intracranial hemorrhage (p = 0.048). Braided stents were associated with a significantly lower rate of permanent morbidity (p = 0.015).

Conclusion: SAC of IAs using laser-cut stents or braided stents was effective and safe. Rates of thromboembolic events, stent stenosis, mortality, and recanalization were comparable between the stent types. Braided stents were associated with lower permanent morbidity while laser-cut stents were associated with more favorable rates of successful deployment and periprocedural intracranial hemorrhage.

Factors related to microcatheter passage through the trans-cell approach using a low-profile visualized intraluminal support device: an in-vitro study

BACKGROUND AND PURPOSE

The trans-cell approach using a low-profile visualized intraluminal support (LVIS) device is sometimes used for aneurysm coil embolization. However, factors related to microcatheter passage remain uninvestigated. We aimed to examine in-vitro factors related to microcatheter passage using the trans-cell approach with an LVIS.

METHODS

Silicone vessel models (inner diameter, 4 mm) were created with different bend segments and a 4-mm hole assuming an aneurysm neck on the side of the greater curvature. The LVIS Blue (4.5 × 32 mm) was deployed at the bend segment, and passability on the trans-cell surface was evaluated by passing the microcatheter along the micro guidewire. A total of 800 passage experiments were performed using two types of microcatheter, ten types of silicone vessel, four cell widths, five cells with the same LVIS device, and two micro guidewire directions in the aneurysm.

RESULTS

The Headway Duo microcatheter (35.5%, 142/400) tended to have better passability compared with the Headway 17 microcatheter (29.3%, 117/400) (p = 0.070). As the cell width and angle between the trans-cell surface and microcatheter direction increased, passability significantly increased (p = 0.027 and p < 0.001, respectively). There was no significant difference in passability when the micro guidewire was directed to the proximal side versus the distal side (p = 0.45).

CONCLUSIONS

A large cell width and an obtuse angle between the trans-cell surface and microcatheter direction facilitated good passability. Although statistically marginal, microcatheters with small ledges and small tips had relatively good passability.

Pivotal trial of the Neuroform Atlas stent for treatment of posterior circulation aneurysms: one-year outcomes

BACKGROUND

Stent-assisted coiling of wide-necked intracranial aneurysms (IAs) using the Neuroform Atlas Stent System (Atlas) has shown promising results.

OBJECTIVE

To present the primary efficacy and safety results of the ATLAS Investigational Device Exemption (IDE) trial in a cohort of patients with posterior circulation IAs.

METHODS

The ATLAS trial is a prospective, multicenter, single-arm, open-label study of unruptured, wide-necked, IAs treated with the Atlas stent and adjunctive coiling. This study reports the results of patients with posterior circulation IAs. The primary efficacy endpoint was complete aneurysm occlusion (Raymond-Roy (RR) class I) on 12-month angiography, in the absence of re-treatment or parent artery stenosis >50%. The primary safety endpoint was any major ipsilateral stroke or neurological death within 12 months. Adjudication of the primary endpoints was performed by an imaging core laboratory and a Clinical Events Committee.

RESULTS

The ATLAS trial enrolled and treated 116 patients at 25 medical centers with unruptured, wide-necked, posterior circulation IAs (mean age 60.2±10.5 years, 81.0% (94/116) female). Stents were placed in all patients with 100% technical success rate. A total of 95/116 (81.9%) patients had complete angiographic follow-up at 12 months, of whom 81 (85.3%) had complete aneurysm occlusion (RR class I). The primary effectiveness outcome was achieved in 76.7% (95% CI 67.0% to 86.5%) of patients. Overall, major ipsilateral stroke and secondary persistent neurological deficit occurred in 4.3% (5/116) and 1.7% (2/116) of patients, respectively.

CONCLUSIONS

In the ATLAS IDE posterior circulation cohort, the Neuroform Atlas Stent System with adjunctive coiling demonstrated high rates of technical and safety performance.Trial registration number https://clinicaltrials.gov/ct2/show/NCT02340585.

Stent-assisted coiling of cerebral aneurysms: Head to head comparison between the Neuroform Atlas and EZ stents

BACKGROUND

The Neuroform Atlas stent is thought to have features allowing for an improved stent delivery system. We aimed to provide a comparison of the Atlas and Neuroform EZ stents in patients treated with stent-assisted coiling.

METHODS

Seventy-seven aneurysms treated with the Atlas stent and 77 aneurysms with similar characteristics treated with the EZ stent were retrospectively compared. Outcomes included angiographic occlusion per the Raymond-Roy (RR) scale, recanalization, retreatment and procedural complications.

RESULTS

With the Atlas stent, technical success was 100% and immediate RR1 occlusion was 81.8%. Follow-up RR1 was achieved in 83.7%. The recanalization rate was 7% and the retreatment rate was 4.6%. The complication rate was 6.5% (new neurological deficit in 1.3%). With the EZ stent, technical success was 96%, immediate RR1 occlusion was 67.6% and follow-up RR1 was 67.6%. The recanalization rate was 12.7% and the retreatment rate was 14.1%. The complication rate was 10.4% (new neurological deficit in 2.6%). The rate of immediate RR1 occlusion was significantly higher with the Atlas stent (p = 0.03), and the rate of follow-up RR1 was nonsignificantly higher with the Atlas stent (p = 0.08). The retreatment rate was significantly lower with the Atlas stent (p = 0.009). There were no significant differences in the rates of recanalization (p = 0.5) and complications (p = 0.6).

CONCLUSIONS

Stent-assisted coiling with the Atlas stent is safe and effective and shows better immediate results as compared to the EZ stent, with improved overall follow-up outcomes.

Two-center experience with Neuroform Atlas stent-assisted coil occlusion of broad-based intracranial aneurysms

PURPOSE

Stent-assisted coiling (SAC) represents an established treatment option for broad-based intracranial aneurysms. Here we report our initial and follow-up experience with the Neuroform Atlas Stent, a hybrid open- and closed-cell low-profile stent in the treatment of broad-based aneurysms.

METHODS

All intracranial aneurysms treated by SAC with the intention to apply the Neuroform Atlas Stent between July 2015 and December 2019 were included. Angiographic and clinical results were analyzed including all follow-up examinations.

RESULTS

A total of 119 aneurysms (8 acutely ruptured) in 112 patients were included. In 19 cases (16.0%) re-catheterization of the aneurysm was performed in a second procedure after failure to re-cross the stent initially. Of all aneurysms, 83.2% (99/119) were completely occluded following the procedure. In 75.6% of all cases (90/119), a single microcatheter was used for both, implantation of the stent and coil occlusion of the aneurysm. At 3-6 and 12 months follow-up, the complete occlusion rates were 75.2 (79/105) and 81.3% (74/91). The thromboembolic (stent thrombosis) and hemorrhagic complication rate was 1.7 (2/119) and 0.8% (1/119), respectively, resulting in a procedure-related morbidity and mortality rate of 0.9 and 0.9% (1/112 patients).

CONCLUSION

SAC using the Neuroform Atlas Stent offers a safe and effective option to treat broad-based intracranial aneurysms with a high angiographic and clinical success rate. In the majority of procedures, the application of two mircocatheters is not required. Prospective comparative studies might help to identify the value of SAC using the Neuroform Atlas Stent among the growing treatment options for broad-based aneurysms.

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

OBJECTIVE

The Neuroform Atlas (Stryker Neurovascular, Fremont, CA, USA) is a low-profile laser cut self-expanding nitinol stent designed to provide coil support and wall apposition during aneurysm embolisation. In this study, we performed a meta-analysis of outcomes after treatment with the Neuroform Atlas stent for the purpose of coil embolisation.

METHODS

The primary objectives of this meta-analysis were to define the safety (treatment-related complications, neurologic outcomes, mortality rate) and the efficacy (aneurysm occlusion rate) of the treatment of intracranial aneurysms with the Neuroform Atlas stent. A systematic review and meta-analysis was performed by searching PubMed, EMBASE, and the Cochrane CENTRAL Library for all published studies on the treatment of intracranial aneurysms with the Neuroform Atlas device up to 6 April 2020. The review was prepared in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 14 studies were analysed (577 patients with 593 intracranial aneurysms). The mean age was 58.2 years and 35.6% were male. Technical success of the procedure was 100%. RROC1/RROC2 (Raymond-Roy occlusion classification (RROC) 1/2) (total occlusion/neck remnant) at a mean follow-up of 8.9 months was achieved in 94.8%. RROC3 was 4.9%. All-cause mortality was 1.8% and permanent residual neurological deficit or disability was 2.7%. Overall complications at follow-up were 6.2%.

CONCLUSION

Our analysis demonstrated good rates of occlusion at follow-up for aneurysms treated with the Atlas device at follow-up. The safety profile appears similar to other low-profile intracranial stents.

Initial Experience of Coil Embolization for Unruptured Intracranial Aneurysm Combined with Neuroform Atlas and Undersized Flexible Coils

Objective

Intraprocedural rupture (IPR) is a rare complication that can occur during endovascular treatment (EVT) of unruptured intracranial aneurysms (UIAs). However, it leads to high morbidity and mortality rates. Others have showed that coil flexibility is a risk factor for IPR. Neuroform Atlas (NA) stents can be deployed with 0.0165-inch microcatheters to enable stent assisted coiling (SAC) with a high likelihood. Undersized flexible coils can be inserted initially during SAC. This study aimed to determine whether SAC using NA and highly flexible coils for UIAs can be conducted without IPR.

Methods

We retrospectively analyzed nine consecutive patients (mean age, 73.2 years; female, n = 6) who underwent SAC for UIAs combined with NA stents and undersized flexible coils between January 2017 and December 2019. Two aneurysms were located at the internal carotid artery (ICA), and one each was located at the ICA-posterior communicating, anterior communicating, middle cerebral, vertebral, vertebra-posterior inferior cerebral and basilar arteries. The mean size of the aneurysms was 4.6 (range, 3.1-8.6) mm. SAC proceeded using the jailing technique. All coils were selected from among the most flexible coils available. We retrospectively assessed technical success rates, aneurysm occlusion at final digital subtraction angiography (DSA), volume embolization ratios (VERs), rates of IPR and symptomatic stroke within 30 days, angiographic findings of aneurysm occlusion at 3 months post-procedure and late adverse events (frequency of aneurysmal rupture, ipsilateral ischemic stroke, and retreated targeted aneurysms).

Results

The technical success rate was 100%. Complete occlusion (CO) was immediate in 8 (89%) patients and a neck remnant persisted in 1 (11%). No IPR or symptomatic stroke developed within 30 days. During a mean follow-up period of 11.8 months, CO persisted in 8 (89%) patients. No late adverse events occurred.

Conclusion

The early clinical and angiographic findings of SAC for UIAs combined with an NA stent and undersized flexible coils were favorable for this series.

Outcomes of Stent-Assisted Coiling Using the Neuroform Atlas Stent in Unruptured Wide-Necked Intracranial Aneurysms

Objective

Although stent-assisted coiling (SAC) has been reported to be safe and effective in treating wide-necked aneurysms, the technique has procedure-related complications. Thus, we reported our experiences of SAC using the Neuroform Atlas stent in treating wide-necked aneurysms and evaluated the incidence of and risk factors for procedure-related complications.

Methods

From March 2018 to August 2019, we treated 130 unruptured wide-necked aneurysms in 123 patients with Neuroform Atlas stents. Angiographic results and clinical outcomes were reviewed retrospectively. Clinical and angiographic follow-up were performed in all cases (mean, 12.4 months) after the procedure.

Results

There were eight cases (6.2%) of procedure-related complications (two dissections, five thromboembolisms, and one hemorrhage) and two (1.5%) of delayed complications (one ischemia and one hemorrhage). There was one case (0.8%) of failure of stent deployment and one (0.8%) of suboptimal positioning of the stent. Follow-up angiography showed complete obliteration in 103 (79.2%), residual neck in 16 (12.3%), and residual aneurysm in 11 cases (8.5%). Aneurysm locations in the middle cerebral artery (odds ratio [OR], 2.211; p=0.046) and the anterior communicating artery (OR, 2.850; p=0.039) were associated with procedure-related complications on univariate analysis. However, no independent risk factor for procedure-related complications was noted in multivariate analysis.

Conclusion

The Neuroform Atlas showed a high rate of technical success. Good clinical and radiographic outcomes in early follow-up suggests that the device is feasible and safe. SAC of aneurysms on the middle cerebral artery or anterior communicating artery may require more attention to prevent possible procedure-related complications.

Pivotal Trial of the Neuroform Atlas Stent for Treatment of Anterior Circulation Aneurysms: One-Year Outcomes

BACKGROUND AND PURPOSE

Stent-assisted coil embolization using the new generation Neuroform Atlas Stent System has shown promising safety and efficacy. The primary study results of the anterior circulation aneurysm cohort of the treatment of wide-neck, saccular, intracranial, aneurysms with the Neuroform Atlas Stent System (ATLAS trial [Safety and Effectiveness of the Treatment of Wide Neck, Saccular Intracranial Aneurysms With the Neuroform Atlas Stent System]) are presented.

METHODS

ATLAS IDE trial (Investigational Device Exemption) is a prospective, multicenter, single-arm, open-label study of wide-neck (neck ≥4 mm or dome-to-neck ratio <2) intracranial aneurysms in the anterior circulation treated with the Neuroform Atlas Stent and approved coils. The primary efficacy end point was complete aneurysm occlusion (Raymond-Roy class 1) on 12-month angiography, in the absence of retreatment or parent artery stenosis (>50%) at the target location. The primary safety end point was any major stroke or ipsilateral stroke or neurological death within 12 months. Adjudication of the primary end points was performed by an independent Imaging Core Laboratory and the Clinical Events Committee.

RESULTS

A total of 182 patients with wide-neck anterior circulation aneurysms at 25 US centers were enrolled. The mean age was 60.3±11.4 years, 73.1% (133/182) women, and 80.8% (147/182) white. Mean aneurysm size was 6.1±2.2 mm, mean neck width was 4.1±1.2 mm, and mean dome-to-neck ratio was 1.2±0.3. The most frequent aneurysm locations were the anterior communicating artery (64/182, 35.2%), internal carotid artery ophthalmic artery segment (29/182, 15.9%), and middle cerebral artery bifurcation (27/182, 14.8%). Stents were placed in the anticipated anatomic location in all patients. The study met both primary safety and efficacy end points. The composite primary efficacy end point of complete aneurysm occlusion (Raymond-Roy 1) without parent artery stenosis or aneurysm retreatment was achieved in 84.7% (95% CI, 78.6%-90.9%) of patients. Overall, 4.4% (8/182, 95% CI, 1.9%-8.5%) of patients experienced a primary safety end point of major ipsilateral stroke or neurological death.

CONCLUSIONS

In the ATLAS IDE anterior circulation aneurysm cohort premarket approval study, the Neuroform Atlas stent with adjunctive coiling met the primary end points and demonstrated high rates of long-term complete aneurysm occlusion at 12 months, with 100% technical success and <5% morbidity. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02340585.

Multicenter Postmarket Analysis of the Neuroform Atlas Stent for Stent-Assisted Coil Embolization of Intracranial Aneurysms

BACKGROUND AND PURPOSE

The Neuroform Atlas is a new microstent to assist coil embolization of intracranial aneurysms that recently gained FDA approval. We present a postmarket multicenter analysis of the Neuroform Atlas stent.

MATERIALS AND METHODS

On the basis of retrospective chart review from 11 academic centers, we analyzed patients treated with the Neuroform Atlas after FDA exemption from January 2018 to June 2019. Clinical and radiologic parameters included patient demographics, aneurysm characteristics, stent parameters, complications, and outcomes at discharge and last follow-up.

RESULTS

Overall, 128 aneurysms in 128 patients (median age, 62 years) were treated with 138 stents. Risk factors included smoking (59.4%), multiple aneurysms (27.3%), and family history of aneurysms (16.4%). Most patients were treated electively (93.7%), and 8 (6.3%) underwent treatment within 2 weeks of subarachnoid hemorrhage. Previous aneurysm treatment failure was present in 21% of cases. Wide-neck aneurysms (80.5%), small aneurysm size (<7 mm, 76.6%), and bifurcation aneurysm location (basilar apex, 28.9%; anterior communicating artery, 27.3%; and middle cerebral artery bifurcation, 12.5%) were common. A single stent was used in 92.2% of cases, and a single catheter for both stent placement and coiling was used in 59.4% of cases. Technical complications during stent deployment occurred in 4.7% of cases; symptomatic thromboembolic stroke, in 2.3%; and symptomatic hemorrhage, in 0.8%. Favorable Raymond grades (Raymond-Roy occlusion classification) I and II were achieved in 82.9% at discharge and 89.5% at last follow-up. mRS ≤2 was determined in 96.9% of patients at last follow-up. The immediate Raymond-Roy occlusion classification grade correlated with aneurysm location (P < .0001) and rupture status during treatment (P = .03).

CONCLUSIONS

This multicenter analysis provides a real-world safety and efficacy profile for the treatment of intracranial aneurysms with the Neuroform Atlas stent.

Stent-Assisted Coiling of Intracranial Aneurysms Using a Nitinol-Based Stent (Neuroform Atlas): A Systematic Review and Meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis was to synthesize the latest evidence on the efficacy and safety of Neuroform Atlas-assisted coiling of intracranial aneurysms.

METHODS

We performed a comprehensive search for articles that assessed the efficacy and safety of Neuroform Atlas-assisted coiling of intracranial aneurysms. The outcome measurement was adequate occlusion, defined as Raymond-Roy Class I (RR1) + Raymond-Roy Class II (RR2) by previous studies.

RESULTS

A total of 557 patients (568 aneurysms) from 13 studies were included. The rate of adequate occlusion after the procedure was 88% (83-94%, I²: 72.21%), and the rates of RR1 and RR2 were 68% (60-77%, I²: 81.87%) and 21% (15-27%, I²: 66.10%), respectively. The adequate occlusion rate at 6 months was 90% (81-99%, I²: 58.04%) and 93% (91-96%, I²: 0%) at the end of a mean of 9.03 ± 1.03 months of follow-up. Periprocedural complications occurred in 35 patients [5% (3-8%, I²: 21.28%)]. Subgroup analysis of unruptured aneurysms showed that the rates of adequate occlusion were 85% (78-93%), 90% (79-100%) (6-month follow-up), and 93% (90-96%) (at the end of follow-up). For the wide-necked aneurysm subgroup, the rate of adequate occlusion was 86% (80-93%) and was 93% (89-97%) at the end of follow-up. Meta-regression showed that initial adequate occlusion was influenced by mean aneurysm neck size (p = 0.034).

CONCLUSION

Neuroform Atlas-assisted coiling is associated with an initial adequate occlusion rate of 88% and a periprocedural complication rate of 6%. The rate of initial adequate occlusion was 85% in unruptured aneurysms and 86% in wide-necked aneurysms.

LEVEL OF EVIDENCE

Level 2, Systematic review of non-randomized and single-arm studies.

Efficacy and Safety of Flow-Diverter Therapy for Recurrent Aneurysms after Stent-Assisted Coiling

BACKGROUND AND PURPOSE

Flow-diverter treatment for previously stented aneurysms has been reported to be less effective and prone to complications. In this study, we evaluated the effectiveness and safety of flow diverters for recurrent aneurysms after stent-assisted coiling.

MATERIALS AND METHODS

Patients who underwent flow-diverter placement for recurrent aneurysms after stent-assisted coiling between March 2015 and March 2019 were recruited. Clinical and radiographic characteristics and clinical and angiographic outcomes were retrospectively evaluated.

RESULTS

Among 133 patients who underwent flow-diverter insertion, 17 (male/female ratio = 5:12; mean age, 53.8 years) were treated for recurrent aneurysms after stent placement with (n = 16) or without (n = 1) coiling. Eight patients initially presented with subarachnoid hemorrhage; 7, with headache; and 2, with visual field defects. Angiographic morphology included large/giant saccular in 12 patients, dissecting in 2, fusiform in 1, traumatic pseudoaneurysm in 1, and ruptured blood blister-like aneurysm in 1. The duration between the first treatment and flow-diverter placement ranged from 2 weeks to 15 months (median, 6 months). Flow-diverter placement was successful in all cases without any complications. All patients had favorable outcomes (mRS, 0-2), without any newly appearing symptoms. Aneurysms were followed up with conventional angiography at least once in 6-18 months. Sixteen aneurysms showed complete occlusion, and 1 aneurysm was enlarged.

CONCLUSIONS

Results from this case series investigating flow-diverter placement for recurrent aneurysms after stent-assisted coiling suggested that the procedure is safe and effective. Further study in a larger population may be warranted.

Stent Migration during Coil Embolization with an Open Cell Stent: A Report of Three Cases

Objective

Among 36 cerebral aneurysm cases of stent-assisted coil embolization with the Neuroform Atlas since April 2017, there were three cases of stent migration during the operation. The status of stent deployment, cause of trouble, results of coil embolization, and complications were assessed.

Case Presentations

There were two cases with trouble during stent deployment, a case of internal carotid artery aneurysm, and a case of middle cerebral artery (MCA) aneurysm. The proximal marker of the stent was advanced during stent deployment with the simple pull maneuver, then a part of the stent migrated to the aneurysm sac in both cases. Stent migration to the aneurysm sac during microcatheter navigation by the trans-cell technique occurred in another MCA aneurysm case. No postoperative complications were observed, and a volume embolization ratio (VER) of 24.1%-33% was achieved in these three cases.

Conclusions

The Neuroform Atlas is a safe and convenient stent system. However, stent advancement during deployment and migration during trans-cell microcatheter navigation can occur.

Comparative Outcome Analysis of Enterprise and Neuroform Stent-Assisted Coiling of Cerebral Aneurysms: A Review of the Literature

Introduction

One of the popular treatment strategies for complex cerebral aneurysms with wide necks or low dome-to-neck ratios is stent-assisted coiling. The most widely used intracranial stents for stent-assisted coiling are Neuroform (NF) and Enterprise (EP) stents. The purposes of this study are to review the recent literature of the past 5 years to compare outcomes between the EP and NF stent-assist coiling systems so as to comment on the safety, efficacy, complications, and recurrence rate of stent-assisted coiling in general.

Methods

PubMed was used to search for all published literature of NF or EP stent-assisted coiling of unruptured cerebral aneurysms from January 2014 to August 2019 with the search terms of "Enterprise stent-assisted coiling," "Neuroform stent," and "Neuroform vs. Enterprise stent."

Results

Twenty two publications met the inclusion criteria which encompass 1764 patients and 1873 aneurysms. Out of these 1873 aneurysms, 1007 aneurysms were treated with EP stent and 866 aneurysms were treated with NF stent. The overall outcome was low rates of thromboembolic complications (4.37%) and intracranial hemorrhage (1.13%), low permanent morbidity (1.70%) and mortality (0.40%), and lower rate of recanalization (11%). Data analysis shows an overall higher rate of complication and recurrence of aneurysm and lower overall rate of aneurysmal occlusion in the patients where EP stent was used in comparison to NF stent. However, this difference was not statistically significant.

Conclusions

The review of two stent-assisted coiling devices using EP and NF stents including 1873 aneurysms in 1764 patients revealed that overall, it is safe and effective with comparable outcomes.