The FRESH Study: Treatment of Intracranial Aneurysms with the New FRED X Flow Diverter with Antithrombotic Surface Treatment Technology-First Multicenter Experience in 161 Patients

The FRED-X Flow Diverter-An Australian Experience

BACKGROUND

The FRED X flow diverter features antithrombotic surface treatment to reduce thrombogenicity. This study evaluated the safety and efficacy of FRED X in treating intracranial aneurysms in the Australian setting.

METHODS

Clinical, procedural and imaging data were retrospectively reviewed for a consecutive series of patients at a single Australian neurovascular centre. Follow-up imaging was performed with a combination of MRA and IV-DSA imaging.

RESULTS

A total of 39 consecutive patients (21% presenting with acute rupture) with 52 aneurysms treated with 40 FRED X devices between June 2021 and September 2024 were included in this study. Aneurysms were predominantly saccular (88%) and located in the ICA (82%), with a median size of 5.1 mm (IQR 2.4-8). Satisfactory wall apposition was achieved in 98% of cases. Additional coiling was performed in 20%, and balloon angioplasty in 5%. At a median follow-up of 28 weeks, complete aneurysm occlusion was achieved in 74% of cases, with adequate occlusion (> 90%) in 86%. Minor adverse events occurred in 10% and major adverse events in 5%. Overall mortality was 5%, exclusively in acute subarachnoid haemorrhage cases.

CONCLUSION

The FRED X demonstrates favourable safety and efficacy profiles, with high technical success rates and satisfactory occlusion outcomes in an Australian setting. Thrombotic complications were rare, possibly reflecting the benefits of the antithrombotic coating, though larger studies with longer-term follow-up are needed for confirmation.

Safety and efficacy of flow redirection endoluminal device (FRED) for treatment of intracranial aneurysm; A systematic review and meta-analysis

BackgroundPrevious research has shown promising results for treating intracranial aneurysms (IAs) with a flow redirection endoluminal device (FRED). In this systematic review and meta-analysis, we aimed to assess the safety and efficacy of this device by providing pooled estimates using the data from previous studies.MethodsA systematic literature search of Web of Sciences, PubMed, Scopus, and Embase was performed until October 8th, 2023. After selecting the final articles, relevant data were extracted. Parameters relating to safety and efficacy were pooled using STATA software. Heterogeneity was assessed using I-squared and Cochran's Q. Funnel plots and Egger's regression methods were used to evaluate publication bias. Sensitivity analysis was also performed using the leave-one-out method.ResultsThe data of 37 studies were used for meta-analysis. The rates of immediate adequate occlusion and complete occlusion were 0.51 (95% CI: 0.31-0.71) and 0.34 (95% CI: 0.16-0.53), respectively, while the rates of the adequate and complete occlusion at the latest follow-up were 0.90 (95% CI: 0.84-0.94) and 0.75 (95% CI: 0.65-0.84), respectively. The periprocedural complications rate was 0.04 (95% CI: 0.03-0.06), and the overall complications rate was 0.12 (95% CI: 0.09-0.15). The rate of good functional outcome was 0.99 (95% CI: 0.99-1.00) and the successful implantation rate was 1.00 (95% CI: 1.00-1.00). There was substantial heterogeneity among the reports for most of the evaluated parameters.ConclusionFRED had high safety and efficacy in treating IAs, as evidenced by its high occlusion and low complication rates.

Systematic evaluation of neuro-ophthalmic outcomes of the ophthalmic artery covered by flow-diverter

Carotid-ophthalmic aneurysms (COA) are complex and severe intracranial arterial lesions, and their treatment and management have always been a focus of clinical research. In recent years, the introduction of flow diverters (FD) has provided a revolutionary method for the treatment of intracranial aneurysms (IA). Although FD has achieved significant success in reducing the risk of COA rupture, the complex anatomical structure and critical function of the ophthalmic artery (OphA) mean that covering the OphA with FD may lead to adverse ophthalmic outcomes. This review aims to systematically examine the ocular complications and their mechanisms when FD covers the OphA in the treatment of COA, emphasizing the potential risks that clinicians should be aware of when applying FD treatment, to reduce complications and improve the overall prognosis of patients.

The Neck-Crossing Technique Using the Low-Profile Distal Access Catheter in Flow Diverter Placement for Dissecting Posterior Cerebral Artery Aneurysm: A Case Report

We report a case in which a novel distal access catheter proved successful in the placement of a flow diverter for a challenging distal cerebral artery lesion. We discuss the advantages and pitfalls of this technique and considerations for its use. A 74-year-old female presented with intermittent headaches, and was diagnosed with a dissecting aneurysm at the proximal right posterior cerebral artery with a sharp bleb, measuring 9.8 mm in diameter. Given the complex vascular anatomy, stent-assisted coil embolization was initially considered but deemed high risk for dual catheter for jailing technique with 6-Fr size guiding catheter due to the tortuosity and stenosis of the parent vessel. Therefore, we opted for flow diverter treatment, which presented its challenges during delivery. By employing a low-profile distal access catheter, Phenom Plus (outer diameter: 4.2-Fr. inner diameter: 1.13 mm; Medtronic, Minneapolis, Minnesota, United States), with a minimal ledge between it and the delivery catheter, Phenom 27 (outer diameter: 2.8-Fr, 0.91 mm; Medtronic), we successfully crossed the neck of the aneurysm with Phenom Plus and placed the flow diverter. While acknowledging potential risks, this case demonstrates the value of the neck-crossing technique using a low-profile distal access catheter as an alternative option for treating challenging peripheral artery aneurysms with flow diverters. This technique offers promise in specific situations where conventional methods pose challenges.

The DERIVO 2 Heal Embolization Device in the Treatment of Ruptured and Unruptured Intracranial Aneurysms: a Retrospective Multicenter Study

BACKROUND

The use of flow diverting stents in the treatment of intracranial aneurysms is associated with a risk of neurological morbidity due to their thrombogenicity. To reduce this risk different surface modifications have been developed. The Derivo 2 Embolization Device (Acandis, Pforzheim, Germany) has proven to be a safe and effective flow diverter. To overcome the risk of thrombo-embolism, the device was modified by adding an anti-thrombogenic fibrin-heparin coating. We aimed to assess the safety and effectiveness of the Derivo 2 heal Embolization Device.

METHODS

Retrospective multicenter data from nine German neurovascular centers between February 2022 until December 2023 were used. Patients treated with the Derivo 2 heal Embolization Device for unruptured or ruptured intracranial aneurysms were included. Peri- and postprocedural adverse events, clinical outcomes, and angiographic follow-up results were evaluated.

RESULTS

84 patients (73.8% female; mean age 58.7 years) with 89 aneurysms (mean size 9.8 mm) were included. 87.6% were located in the anterior circulation. Most of them were sidewall aneurysms (88.8%). 96 flow diverters were used. 99.0% were successfully implanted. An in-stent balloon angioplasty was performed in 6.0% of the cases. An additional coiling was performed in 28.6%. Technical difficulties were present in 12.0% of the cases. Thrombotic events occurred in 4.8% with no neurological sequelae. Mortality and morbidity were 0 and 1.2% respectively. Adequate aneurysm occlusion was achieved in 80.7% with a mean follow-up time of 6.6 months.

CONCLUSION

The Derivo 2 heal Embolization Device showed a satisfying aneurysm occlusion and safety with a low rate of neurological morbidity.

Multicenter study of HPC coated p48 and p64 flow diverters for treatment of intracranial aneurysms under dual antiplatelet therapy

OBJECTIVE

Phenox flow diverters (p64 and its smaller vessel variant p48) represent an established treatment option for intracranial aneurysms. This study evaluates the safety and efficacy of the new generation of these devices with an additional antithrombotic surface coating (HPC).

METHODS

Consecutive patients treated between 2020 and 2023 at three institutions were retrospectively reviewed for aneurysm characteristics, procedural details, complications, and angiographic outcomes.

RESULTS

Sixty-one patients (mean age 56 years) were treated for 61 aneurysms. The mean aneurysm size was 8.3 ± 4.9 mm, 12 (19.7%) were ruptured, 16 (26.2%) were recurrent after previous treatment, 10 (16.4%) were located in the posterior circulation, and 7 (11.5%) had nonsaccular morphology. All procedures were technically successful, with a single device sufficient in 60/61 (98%) cases. Delivery problems included device twisting in one case and incomplete proximal opening in another. Additional angioplasty was performed in 3/61 (4.9%) procedures and additional coiling in 4 (6.6%). There were 3 (4.9%) major events (1 thromboembolic ischemic stroke, 1 fatal intracranial hemorrhage, and 1 delayed aneurysm rupture) and 6 (9.8%) minor strokes. Follow up at a mean of 6 months showed complete occlusion in 33/42 (79%) aneurysms, neck remnants in 5 (12%), and aneurysm remnants in 4 (10%).

CONCLUSIONS

The results demonstrate comparable acceptable complication rates and angiographic results of the Phenox HPC, which are similar to other flow diverters. Long-term and comparative studies are needed to evaluate the full potential of these devices.

Flow diversion in the treatment of intracranial aneurysms using the novel FRED X device: An early experience from a single high-volume center

BACKGROUND

The Flow Re-Direction Endoluminal Device X (FRED X) offers several benefits over other flow-diverter devices including an antithrombotic coating, optimized in-vessel stability, and increased flexibility for easier device placement. We present a to-date experience of the safety and utility of the FRED X device in the repair of posterior and anterior circulation aneurysms.

METHODS

A retrospective review was conducted on all endovascular procedures that utilized the FRED X device at our center from May 2022 to November 2023.

RESULTS

77 patients (72.7% women, mean age 58.9), underwent a total of 85 procedures using the FRED X device. Indications included treatment of incidentally discovered aneurysms, acute dissections, aneurysm rupture, repair of residual filling following prior intervention, and use of FRED X for recanalization of non-aneurysmal extracranial stroke. 31.3% of the aneurysms were in the posterior circulation, 68.7% were in the anterior circulation. 9.4% of patients presented with SAH due to acute aneurysm rupture. Patients treated with FRED X were separated into OFF-Label (40.0%) or ON-label (60.0%) indications. Occlusion rate at 6-month follow-up were 72.2% in the OFF-label group, 66.7% in the ON-label group, and 68.4% overall. Rate of major periprocedural complications was 1.2% and the cumulative rate of postprocedural complication at follow-up was 5.3%.

CONCLUSION

This study shows that FRED X treatment of intracranial aneurysms is safe in both OFF-label and ON-label indications. Continued follow-up of our patient population will further establish the safety, efficacy, and long-term stability of this device.

Safety and efficacy of coated flow diverters in the treatment of ruptured intracranial aneurysms: a retrospective multicenter study

BACKGROUND

This multicenter study evaluated the safety and efficacy of coated flow diverters (cFDs) for the treatment of ruptured intracranial aneurysms.

METHODS

Consecutive patients treated with different cFDs for ruptured aneurysms under tirofiban at eight neurovascular centers between 2016 and 2023 were retrospectively analyzed. The majority of patients were loaded with dual antiplatelet therapy after the treatment. Aneurysm occlusion was determined using the O'Kelly-Marotta (OKM) grading scale. Primary outcome measures were major procedural complications and aneurysmal rebleeding during hospitalization.

RESULTS

The study included 60 aneurysms (posterior circulation: 28 (47%)) with a mean size of 5.8±4.7 mm. Aneurysm morphology was saccular in 28 (47%), blister-like in 12 (20%), dissecting in 13 (22%), and fusiform in 7 (12%). Technical success was 100% with a mean of 1.1 cFDs implanted per aneurysm. Adjunctive coiling was performed in 11 (18%) aneurysms. Immediate contrast retention was observed in 45 (75%) aneurysms. There was 1 (2%) major procedural complication (a major stroke, eventually leading to death) and no aneurysmal rebleeding. A good outcome (modified Rankin Scale 0-2) was achieved in 40 (67%) patients. At a mean follow-up of 6 months, 27/34 (79%) aneurysms were completely occluded (OKM D), 3/34 (9%) had an entry remnant (OKM C), and 4/34 (12%) had residual filling (OKM A or B). There was 1 (3%) severe in-stent stenosis during follow-up that was treated with balloon angioplasty.

CONCLUSIONS

Treatment of ruptured aneurysms with cFDs was reasonably safe and efficient and thus represents a valid treatment option, especially for complex cases.

Safety and effectiveness assessment of the surpass evolve (SEASE): a post-market international multicenter study

BACKGROUND

Flow diverters are the first-line treatment for specific intracranial aneurysms (iA). Surpass Evolve (SE) is a new-generation 64-wire flow diverter with a high braid angle. Current literature on the SE is limited. We aimed to report the first international real-world experience evaluating the safety and effectiveness of the SE.

METHODS

The Safety and Effectiveness Assessment of the Surpass Evolve (SEASE) was a multicenter retrospective international post-marketing cohort study including consecutive patients treated with SE for iAs between 2020 and 2022. Demographic, clinical, and angiographic data were collected. Primary effectiveness was independent core lab adjudicated complete occlusion rates (Raymond-Roy Class 1) at last follow-up. Primary safety were major ischemic/hemorrhagic events and mortality.

RESULTS

In total, 305 patients with 332 aneurysms underwent SE implantation. The patients had a median age of 59 [50-67] years, and 256 (83.9%) were female. The baseline modified Rankin scale score was 0-2 in 291 patients (96.7%). Most aneurysms were unruptured (285, 93.4%) and saccular (309, 93.1%). Previous treatment was present in 76 (22.9%) patients. The median aneurysm size was 5.1 [3.4-9.0] mm, and the median neck width was 3.6 [2.7-5.1] mm. Most aneurysms were in the internal carotid artery C6 ophthalmic segment (126, 38.0%), followed by the communicating segment (58, 17.5%). At median 10.2 [6.4-12.9] months follow-up, 233 (73.0%) aneurysms achieved complete occlusion. After adjusting for confounders, complete occlusion remained consistent. Major stroke and procedure-related mortality were reported in 6 (2%) and 2 (0.7%) cases, respectively.

CONCLUSION

These results demonstrate that SE has a consistently high effectiveness and favorable safety for the treatment of iAs.

FRED-EPI study: Safety and efficacy of FRED/FRED Jr aneurysm treatment in current clinical practice

OBJECTIVE

Flow diversion is increasingly used as an endovascular treatment for intracranial aneurysms. FRED-EPI is a prospective, multicenter, French study, conducted to analyze the safety and efficacy of aneurysm treatment with FRED/FRED Jr (Microvention, AlisoViejo, CA, USA) in current clinical practice.

PATIENTS AND METHODS

Patients with intracranial aneurysms treated with FRED and FRED Jr who agreed to participate were prospectively and consecutively included in all French centers using these devices.

RESULTS

From June 2020 to January 2022, 135 patients (110 females, 81.5%, and 25 males, 18.5%) with 154 aneurysms were included in 13 French interventional neuroradiology centers. The mean age was 53.9 ± 12.2 years (range: 20 - 77 years). Aneurysm was unruptured in 123 cases (79.9%), ruptured in 4 cases (2.6%), and recanalized in 27 cases (17.5%). Most aneurysms were small (135/154, 87.7%). Aneurysm locations were supraclinoid ICA in 83 (53.9%), cavernous and petrous ICA in 25 (16.2%), anterior cerebral artery or anterior communicating artery in 19 (12.3%), MCA in 7 (4.5%), and posterior circulation in 20 (13.0%). Three patients (2.2%) had hemorrhagic complications (1 delayed aneurysm rupture and 2 delayed remote hematoma) and 3 (2.2%) ischemic complications (2 intrastent thrombosis and 1 stroke related to atherosclerosis) leading to 1-year morbimortality of 4.4%. Complete aneurysm occlusion was reported in 105/139 aneurysms (75.5%).

CONCLUSIONS

FRED-EPI confirms good safety of aneurysm treatment with FRED/FRED Jr in current clinical practice with 4.4% 1-year morbimortality.

FRED X flow diversion stenting for unruptured intracranial aneurysms: US multicenter post-market study

BACKGROUND

The Flow Re-direction Endoluminal Device (FRED) X is a next generation flow-diverting stent for treating intracranial aneurysms. Its surface modification (X technology) aims to minimize device thrombogenicity. Early post-market multicenter data from the US are lacking.

METHODS

We conducted a retrospective multicenter analysis of consecutive FRED X procedures performed to treat unruptured intracranial aneurysms at four US centers (March 2022 to January 2024). Cases with ruptured aneurysms or extracranial aneurysm location were excluded (n=10). We assessed patient and aneurysm characteristics, antithrombotic management, safety events, and both clinical and angiographic (effectiveness) outcomes.

RESULTS

In this cohort, 101 patients underwent FRED X stenting for 117 aneurysms. Most aneurysms were saccular in shape (95.7%) and located at the C6-C7 segments of the internal carotid artery (72.6%). Thromboembolic events occurred in 5.9% of the cases, leading to one instance of permanent procedure related morbidity (1.0%). No procedure related mortality (0%) was observed. Device related issues were recorded in 2.0% of cases. At the 6 month follow-up, complete aneurysm occlusion was achieved in 58% of aneurysms. At the last available follow-up (6-12 months), 74.8% of aneurysms were adequately occluded.

CONCLUSIONS

FRED X stenting for unruptured intracranial aneurysms demonstrated low rates of neurological morbidity and periprocedural complications. Early aneurysm occlusion rates were appropriate, but further mid-term and long term follow-up is required. These findings support the early safety and effectiveness of the FRED X device for intracranial aneurysm treatment.

Evaluation of flow diverters for cerebral aneurysm therapy: recommendations for imaging analyses in clinical studies, endorsed by ESMINT, ESNR, OCIN, SILAN, SNIS, and WFITN

BACKGROUND

Multiple studies and meta-analyses have described the technical and clinical outcomes in large cohorts of aneurysm patients treated with flow diverters (FDs). Variations in evaluation methodology complicate making comparisons among studies, hinder understanding of the device behavior, and pose an obstacle in the assessment of further advances in FD therapy.

METHODS

A multidisciplinary panel of neurointerventionalists, imaging experts, and neuroradiologists convened with the goal of establishing consensus recommendations for the standardization of image analyses in FD studies.

RESULTS

A standardized methodology is proposed for evaluating and reporting radiological outcomes of FD treatment of intracranial aneurysms. The recommendations include general imaging considerations for clinical studies and evaluations of longitudinal changes, such as neointimal lining and stenosis. They cover standards for classification of aneurysm location, morphology, measurements, as well as the assessment of aneurysm occlusion, wall apposition, and neck coverage. These reporting standards further define four specific braid deformation patterns: foreshortening, fish-mouthing, braid bump deformation, and braid collapse, collectively termed 'F2B2'.

CONCLUSIONS

When widely applied, standardization of methods of measuring and reporting outcomes will help to harmonize the assessment of treatment outcomes in clinical studies, help facilitate communication of results among specialists, and help enable research and development to focus on specific aspects of FD techniques and technology.

Treatment of Intracranial Aneurysms with the FRED X Flow Diverter Stent: Mid-term Angiographic and Safety Results

PURPOSE

The aim of our study was to assess the mid-term efficacy and safety of the FRED X flow diverting stent (FDS) in the treatment of intracranial aneurysms. The FRED X FDS is relatively new with limited data on its longer-term effectiveness and safety profile.

METHODS

Patients with intracranial aneurysms treated with the FRED X FDS at two UK centres, between March 2021 and July 2022 with at least 18 months follow-up, were retrospectively reviewed. Clinical, procedural and imaging data was analyzed.

RESULTS

Twenty-two patients with 24 aneurysms treated with the FRED X device, and had completed at least 18 months of follow-up, were included in this study. The rate of complete aneurysm occlusion (Raymond-Roy Class I) was 83.3% at a mean follow-up duration of 21.5 months. One case of major adverse event (4.3%) related to a post-procedural stroke which is also the only case of permanent neurological deficit (4.3%) in our cohort. Three cases of minor adverse events (13.0%) and 2 cases of asymptomatic adverse events (8.7%) were also recorded.

CONCLUSION

Use of the FRED X FDS to treat intracranial aneurysms has acceptable safety profile and efficacy in the mid-term.

Comparative analysis of safety and efficacy of flow diversion with and without surface modification technology, FRED-X, FRED, PED shield and PED in 386 patients: A single center experience with systematic review and network meta analysis

INTRODUCTION

The FRED-X is a newer generation flow diverting stent (FDS) with surface modification that has demonstrated favorable efficacy in treating intracranial aneurysms. Our study provides an analysis of patients treated using FRED-X compared to FRED, PED Shield and PED.

MATERIALS AND METHODS

This was a retrospective single center study and a systematic review with network meta analysis of patients who underwent flow diversion using FRED-X, FRED, PED Shield or PED. Multivariate logistic regression was used to assess long-term outcomes of interest- angiographic occlusion, in-stent stenosis and functional outcome at 6- and 12-month follow up.

RESULTS

386 patients with 386 aneurysms were included. The average age of the cohort was 56.2 years, and 81 % was female. PED had significantly higher aneurysm occlusion rates compared to FRED-X at 6- and 12-months (OR: 3.03, 95 % CI: 1.36-6.62 and OR: 4.01, 95 % CI: 1.26-12.2), with higher odds of absent in-stent stenosis (OR: 9.03, 95 % CI: 3.63-23.3 and OR: 9.58, 95 % CI: 2.56-33.8) at 6- and 12-months, respectively. Rates of stroke, TIA, ICH and mortality were not significantly different across cohorts. All patients were functionally independent on follow-up. A network meta-analysis revealed no significant difference in occlusion rates among each of the included FDS.

CONCLUSION

Our study revealed comparable 12-month occlusion rates and in-stent stenosis between surface modified devices, FRED-X and PED Shield. In addition, angiographic results were comparable between FRED-X and the first generation FRED, however classic PED demonstrated higher rates of angiographic occlusion with lower in-stent stenosis.

Flow diverter stents for endovascular treatment of aneurysms: a comparative study of efficacy and safety between FREDX and FRED

BACKGROUND

The FRED X flow diverter (FREDX), as the second generation in the FRED series, aims to improve the treatment of cerebral aneurysms. This study compares the efficacy and safety of FREDX with its predecessor, FRED.

METHODS

This prospective registry included patients treated with FRED and FREDX devices. Efficacy was assessed using digital subtraction angiography with 3D volumetric reconstruction at immediate and 1 year follow-ups. Safety was evaluated by recording complications, analyzed through univariate contrasts, generalized mixed models, and Bayesian network analyses.

RESULTS

We treated 287 patients with 385 aneurysms, with 77.9% receiving FRED and 22.1% FREDX. The median age was 55 years (IQR 47-65) and 78.4% were women. The FREDX group showed a higher prevalence of saccular-like aneurysms (70.6% vs 52.7%, P=0.012) and a higher rate of complete occlusion compared with FRED interventions (79.4% vs 59.3%, P=0.022). After adjusting for confounders, these differences represented a 3.04-fold increased likelihood (95% CI 1.44 to 6.41, P=0.003) of achieving complete occlusion at 1 year with FREDX interventions. Regarding safety, two (3.5%) complications (both non-symptomatic) were observed in the FREDX group and 23 (10.4%) in the FRED group (P=0.166). Bayesian network analysis suggested a trend towards fewer complications for FREDX, with a median reduction of 5.5% in the posterior distribution of the prevalence of complications compared with FRED interventions.

CONCLUSIONS

The FREDX device shows improved complete occlusion rates at 1 year compared with the FRED device while maintaining a favourable safety profile, indicating its potential advantage in the treatment of cerebral aneurysms.

Safety and efficacy of coated flow diverters in the treatment of cerebral aneurysms during single antiplatelet therapy: A multicenter study

OBJECTIVE

This multicenter study evaluates the safety and efficacy of coated flow diverters (cFDs) for the treatment of cerebral aneurysms under single antiplatelet therapy (SAPT).

METHODS

This is a retrospective, observational study of 41 patients (median age: 58 years) with 41 aneurysms (median size: 7 mm, 29 [71%] saccular, 9 [22%] ruptured) treated with cFDs at four neurovascular centers between 2020 and 2023. Scheduled cases received continuous SAPT starting seven days before the procedure. Emergency cases were treated with tirofiban followed by SAPT loading. The safety endpoint was ischemic complications occurring during the procedure and within four months of clinical follow-up.

RESULTS

The Pipeline Vantage or Flex Shield was used in 26 (63%) procedures, the FRED X in 12 (29%), the p48/64 Hydrophilic Polymer Coating in 2 (5%), and the Derivo Embolization Device 2heal in 1 (2%). Single antiplatelet therapy consisted of prasugrel in 27 (66%) patients, ticagrelor in 9 (22%), and ASA in 5 (12%). There were 2 (5%) early ischemic complications (one minor stroke and one transient ischemic attack). There were no late ischemic complications in the four-month follow-up of 35 patients. The six dropouts included four nontreatment-related deaths after subarachnoid hemorrhage and two patients with a poor outcome after subarachnoid hemorrhage. Complete and favorable occlusion rates (median: 7 months) were 75% (27/36) and 89% (32/36), respectively.

CONCLUSIONS

Coated flow diverter implantation in the setting of SAPT was safe and effective and warrants confirmation in a prospective comparative trial.

Role and Safety of Tirofiban in Peri-Interventional Antiplatelet Management for Aneurysm Treatment

BACKGROUND

Tirofiban is administered for the treatment of aneurysms in cases of thromboembolic complications, as well as in cases of acute stenting or flow-diverter implantation required within the scope of aneurysm treatment. We aimed to investigate the efficacy and safety of tirofiban in this group of patients.

METHODS

We conducted a retrospective analysis of all patients undergoing aneurysm treatment and receiving peri-interventional tirofiban administration at our institution between 2009 and 2019.

RESULTS

A total of 105 patients were included, with 61% women and 39% men (mean age = 53 years, IQR: 44-60 years). Sixty-seven patients underwent emergency aneurysm treatment, and thirty-eight were treated electively. Hemorrhagic events occurred in 22% (15/67) of the patients treated acutely, with 7.46% (5/67) exhibiting symptoms. Patients undergoing elective aneurysm treatment experienced no hemorrhagic events (p = 0.002). Among the 35 patients who required an external ventricular drain (EVD), 22.86% (8/35) developed EVD-related hemorrhages; however, none were symptomatic (p = 0.007). Of the five patients who required a craniotomy, two experienced significant bleeding, and one experienced non-significant craniotomy-related bleeding (p = 0.20).

CONCLUSION

Tirofiban may be safe for use during peri-interventional complications or emergency stenting in aneurysm treatment. However, caution is necessary when craniotomy is required. In elective aneurysm treatments, administering Tirofiban in response to periprocedural complications appears to be safe.

Lower-Ischemic-Risk Profile of Coated Flow Redirection Endoluminal Device X Compared With Uncoated Flow Redirection Endoluminal Device Flow Diverter in the Treatment of Unruptured Intracranial Aneurysms

BACKGROUND AND OBJECTIVES

Flow Redirection Endoluminal Device (FRED) X is a new generation flow diverter with an antithrombotic surface coating. This study compares the procedural safety and short-term efficacy of FRED X with its uncoated predecessor, the FRED.

METHODS

Patients treated with FRED and FRED X devices for unruptured aneurysms between 2013 and 2023 at 3 neurovascular centers were retrospectively reviewed. The procedural ischemic event rate was the safety end point, and the complete aneurysm occlusion rate at 1 year was the efficacy end point. Multivariable regression adjustment and 1:1 propensity score matching were performed to control for potential confounding.

RESULTS

The FRED X group (137 patients) had a higher prevalence of recurrent and bifurcation aneurysms and fewer aneurysms with branch involvement than the FRED X group (156 patients). The ischemic event rate was lower in FRED X (1/156 [0.6%]) than in FRED (7/137 [5.1%]), which was significant after multivariable adjustment (odds ratio: 8.8, 95% CI: 1.1-72.7, P = .04), and tended to be significant in the propensity score analysis (P = .07). Morbidity was comparable between FRED (2.2%) and FRED X (0%, P = .10). The complete occlusion rates of FRED vs FRED X were 73/117 (62.4%) vs 39/54 (72.2%) aneurysms at 6 months (P = .21) and 52/74 (70.3%) vs 27/37 (73.0%) at 12 months (P = .77). Hemorrhagic complications, in-stent stenosis, and clinical events during follow-up and retreatments were not significantly different between groups.

CONCLUSION

This study indicates an improved ischemic risk profile of FRED X while maintaining a favorable efficacy profile, warranting further study and translation into clinical use.

Surface modification of neurovascular stents: from bench to patient

Flow-diverting stents (FDs) for the treatment of cerebrovascular aneurysms are revolutionary. However, these devices require systemic dual antiplatelet therapy (DAPT) to reduce thromboembolic complications. Given the risk of ischemic complications as well as morbidity and contraindications associated with DAPT, demonstrating safety and efficacy for FDs either without DAPT or reducing the duration of DAPT is a priority. The former may be achieved by surface modifications that decrease device thrombogenicity, and the latter by using coatings that expedite endothelial growth. Biomimetics, commonly achieved by grafting hydrophilic and non-interacting polymers to surfaces, can mask the device surface with nature-derived coatings from circulating factors that normally activate coagulation and inflammation. One strategy is to mimic the surfaces of innocuous circulatory system components. Phosphorylcholine and glycan coatings are naturally inspired and present on the surface of all eukaryotic cell membranes. Another strategy involves linking synthetic biocompatible polymer brushes to the surface of a device that disrupts normal interaction with circulating proteins and cells. Finally, drug immobilization can also impart antithrombotic effects that counteract normal foreign body reactions in the circulatory system without systemic effects. Heparin coatings have been explored since the 1960s and used on a variety of blood contacting surfaces. This concept is now being explored for neurovascular devices. Coatings that improve endothelialization are not as clinically mature as anti-thrombogenic coatings. Coronary stents have used an anti-CD34 antibody coating to capture circulating endothelial progenitor cells on the surface, potentially accelerating endothelial integration. Similarly, coatings with CD31 analogs are being explored for neurovascular implants.

Neurological outcomes of flow-diverter stent placement for middle cerebral artery aneurysms, with reference to the effects of argatroban on ischemic events: patient series

BACKGROUND

A systematic review and meta-analysis of flow-diverter stents (FDSs) for the treatment of middle cerebral artery (MCA) aneurysms reported concerns about ischemic complications during treatment. The authors report on the intraoperative and postoperative complications of unruptured MCA aneurysms and their control strategies at their hospital, with detailed information on the aneurysms and a review of the previous literature.

OBSERVATIONS

Intraoperative and perioperative in-stent thrombus occlusion occurred in 3 (37.5%) of the 8 patients evaluated. In cases with in-stent thrombus formation, rapid administration of 10 mg argatroban led to improvement in blood flow, as seen on angiography. Only 1 patient (12.5%) had a symptomatic stroke postoperatively. This patient was admitted for rehabilitation and drug therapy but was discharged from the hospital 10 days postoperatively with a modified Rankin Scale (mRS) score of 1. The patient had an mRS score of 0 at 90 days after surgery and at the last observation.

LESSONS

Ischemic complications require attention during FDS treatment for MCA aneurysms. The use of argatroban in cases of in-stent thrombosis may contribute to a good neurological prognosis. https://thejns.org/doi/10.3171/CASE24237.

Stent coating containing a charged silane coupling agent that regulates protein adsorption to confer antithrombotic and cell-adhesion properties

The evolution of endovascular therapies, particularly in the field of intracranial aneurysm treatment, has been truly remarkable and is characterized by the development of various stents. However, ischemic complications related to thrombosis or downstream emboli pose a challenge for the broader clinical application of such stents. Despite advancements in surface modification technologies, an ideal coating that fulfills all the desired requirements, including anti-thrombogenicity and swift endothelialization, has not been available. To address these issues, we investigated a new coating comprising 3-aminopropyltriethoxysilane (APTES) with both anti-thrombogenic and cell-adhesion properties. We assessed the anti-thrombogenic property of the coating using an in vitro blood loop model by evaluating the platelet count and the level of the thrombin-antithrombin (TAT) complex, and investigating thrombus formation on the surface using scanning electron microscopy (SEM). We then assessed endothelial cell adhesion on the metal surfaces. In vitro blood tests revealed that, compared to a bare stent, the coating significantly inhibited platelet reduction and thrombus formation; more human serum albumin spontaneously adhered to the coated surface to block thrombogenic activation in the blood. Cell adhesion tests also indicated a significant increase in the number of cells adhering to the APTES-coated surfaces compared to the numbers adhering to either the bare stent or the stent coated with an anti-fouling phospholipid polymer. Finally, we performed an in vivo safety test by implanting coated stents into the internal thoracic arteries and ascending pharyngeal arteries of minipigs, and subsequently assessing the health status and vessel patency of the arteries by angiography over the course of 1 week. We found that there were no adverse effects on the pigs and the vascular lumens of their vessels were well maintained in the group with APTES-coated stents. Therefore, our new coating exhibited both high anti-thrombogenicity and cell-adhesion properties, which fulfill the requirements of an implantable stent.

Phenox HPC and Phenox flow modulation devices for the endovascular treatment of intracranial aneurysms: a systematic review and meta-analysis

BACKGROUND

Surface-modified flow diverters are increasingly used in clinical settings. However, their safety profiles and additional benefits over non-coated devices still need to be explored. In this meta-analysis, we aimed to investigate and compare the clinical outcomes of the uncoated Phenox and coated Phenox HPC flow diverters.

METHODS

A systematic literature review was performed using PubMed, Scopus, Embase, and Web of Science databases. Collected data were pooled and corresponding 95% confidence intervals (CI) were calculated. Outcomes of interest included aneurysm occlusion (>6 months) and complication rates. Additionally, the safety outcomes of prophylactic single (SAPT) and dual antiplatelet treatment (DAPT) approaches were compared for patients treated with coated Phenox HPC flow diverters.

RESULTS

We included 17 studies with 1238 patients. The overall complete occlusion rates were 80% (95% CI 74.01% to 86.56%) for Phenox HPC and 71.3% (95% CI 59.71% to 85.20%) for non-coated Phenox flow diverters (p=0.24). Ischemic complication rates were 7.3% (95% CI 4.6% to 11.39%) with the Phenox HPC and 5.3% (95% CI 4.07% to 6.91%) with the Phenox (p=0.24). For patients treated with Phenox HPC, the SAPT (5.5%; 95% CI 2.83% to 10.85%) and DAPT (7.1%; 95% CI 1.23% to 41.45%) approaches resulted in comparable ischemic complication rates (p=0.79). The DAPT group (4.8%; 95% CI 1.46% to 16.24%) had higher hemorrhagic complication rates than the SAPT group (1.7%; 95% CI 0.52% to 6.09%), but the difference was not statistically significant for patients treated with Phenox HPC (p=0.25).

CONCLUSIONS

Our findings indicate that Phenox HPC is equally as safe and effective as non-coated Phenox devices. Additionally, our results suggest that prasugrel monotherapy might effectively prevent ischemic complications in patients treated with Phenox HPC flow diverters.

Prasugrel Single Antiplatelet Therapy versus Aspirin and Clopidogrel Dual Antiplatelet Therapy for Flow Diverter Treatment for Cerebral Aneurysms: A Retrospective Multicenter Study

BACKGROUND AND PURPOSE

The optimal antiplatelet regimen after flow diverter treatment of cerebral aneurysms is still a matter of debate. A single antiplatelet therapy might be advantageous in determined clinical scenarios. This study evaluated the efficacy and safety of prasugrel single antiplatelet therapy versus aspirin and clopidogrel dual antiplatelet therapy.

MATERIALS AND METHODS

We performed a post hoc analysis of 4 retrospective multicenter studies including ruptured and unruptured aneurysms treated with flow diversion using either prasugrel single antiplatelet therapy or dual antiplatelet therapy. Primary end points were the occurrence of any kind of procedure- or device-related thromboembolic complications and complete aneurysm occlusion at the latest radiologic follow-up (mean, 18 months). Dichotomized comparisons of outcomes were performed between single antiplatelet therapy and dual antiplatelet therapy. Additionally, the influence of various patient- and aneurysm-related variables on the occurrence of thromboembolic complications was investigated using multivariable backward logistic regression.

RESULTS

A total of 222 patients with 251 aneurysms were included, 90 (40.5%) in the single antiplatelet therapy and 132 (59.5%) in the dual antiplatelet therapy group. The primary outcome-procedure- or device-related thromboembolic complications-occurred in 6 patients (6.6%) of the single antiplatelet therapy and in 12 patients (9.0%) of the dual antiplatelet therapy group (P = .62; OR, 0.712; 95% CI, 0.260-1.930). The primary treatment efficacy end point was reached in 82 patients (80.4%) of the single antiplatelet therapy and in 115 patients (78.2%) of the dual antiplatelet therapy group (P = .752; OR, 1.141; 95% CI, 0.599-2.101). Logistic regression showed that non-surface-modified flow diverters (P = .014) and fusiform aneurysm morphology (P = .004) significantly increased the probability of thromboembolic complications.

CONCLUSIONS

Prasugrel single antiplatelet therapy after flow diverter treatment may be as safe and effective as dual antiplatelet therapy and could, therefore, be a valid alternative in selected patients. Further prospective comparative studies are required to validate our findings.

Flow Diverters with Surface Modification in Patients with Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND

Flow diverters with surface modification (FDSM) are increasingly being used in the treatment of intracranial aneurysms (ANs). We aimed to evaluate the effectiveness and safety across different devices and antiplatelet therapies using a systematic review and meta-analysis.

METHODS

A systematic review was performed to identify original studies of ≥10 patients with intracranial ANs treated with FDSM from database inception through August 2023. Primary effectiveness outcome was the rate of complete AN occlusion at follow-up ≥6 months. Safety outcomes included ischemic stroke, hemorrhage, and in-stent thrombosis, and were stratified by FDSM devices and antiplatelet therapies. Certainty of evidence was evaluated following the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Twenty-seven studies were included, yielding 2161 patients with 2373 ANs. A total of 70.5% of the ANs were located on the internal carotid artery (ICA). Total 10.3% were acutely ruptured. The complete AN occlusion rate was 72.3% at follow-up ≥6 months. Sensitivity analysis in the ICA AN cohort yielded comparable occlusion rates between Pipeline Flex Embolization Device-Shield (80.4%) and Phenox-hydrophilic polymer-coated (77.5%, P = 0.54), but a lower 66.2% rate for Flow Redirection Endoluminal Device-X (P = 0.02). The rate of in-stent thrombosis and stenosis tended to be higher in Phenox-hydrophilic polymer-coated (3.4%) and Flow Redirection Endoluminal Device-X (4.3%) versus Pipeline Flex Embolization Device-Shield (0.8%, P = 0.05).

CONCLUSIONS

FDSM were safe with satisfactory effectiveness for intracranial ANs. More specific investigations are warranted to explore their performance in ANs beyond the ICA and optimal antiplatelet therapy.

FRED X flow diverter for the treatment of intracranial aneurysms: Two-center experience and mini-review of the literature

OBJECTIVE

The flow re-direction endoluminal device (FRED) is a safe and effective treatment option for intracranial aneurysms. The novel FRED X features an antithrombotic surface coating ("X Technology") on an otherwise unmodified stent design. This two-center study evaluates the clinical safety and efficacy of FRED X and compares it to the literature.

METHODS

Consecutive patients treated between 2020 and 2023 were retrospectively reviewed for aneurysm characteristics, procedural details and complications, and angiographic outcomes. A mini-review of the literature for FRED X clinical trials was performed and results were pooled using a random effects model.

RESULTS

Thirty-four patients (mean age 56 years) were treated for 34 aneurysms. The mean aneurysm size was 7.7 ± 5.0 mm, 7 (21%) were ruptured, 6 (18%) were recurrent after previous treatment, 11 (32.3%) were located in the posterior circulation, and 4 (12.5%) had non-saccular morphology. All procedures were technically successful and no balloon angioplasty was required. There was 1 (2.9%) symptomatic complication (a transient ischemic attack) and no procedural morbidity or mortality. Technical asymptomatic events included 1 procedural stent occlusion that was reopened with thrombectomy and 3 cases of vasospasm. Complete and adequate occlusion rates were 68% (19/28) and 89% (25/28) at a mean follow-up time of 6 months, respectively. The results of this study are comparable to previous FRED X studies.

CONCLUSIONS

The results demonstrate a high feasibility and procedural safety of the FRED X with adequate mid-term occlusion rates. Long-term and comparative studies are needed to evaluate the full potential of the FRED X.

Prediction of obliteration of unruptured cerebral aneurysm by residual aneurysm volume after flow diverter stent treatment

Introduction There is no methodology to predict aneurysm occlusion using residual volume after flow diverter stent treatment. We retrospectively examined whether residual aneurysm volume at 6 months postoperatively can predict the degree of aneurysm obliteration at 1 year after flow diverter stent treatment. Materials and Methods This single institution study included 101 consecutive patients who underwent flow diverter stent treatment for unruptured cerebral aneurysm. Based on pre-treatment aneurysm volume, the percentage residual volume was calculated 6 months postoperatively. The volume of the aneurysm was determined using the volume calculation function of the cerebral angiography equipment. 1 year postoperatively, patients were classified into two groups: the good obliteration group (GG; O'KellyMarotta [OKM] grading scale: C and D) and the poor obliteration group (PG; OKM: A and B). Statistical analysis was performed to determine if there was a difference in residual aneurysm volume percentage at 6 months postoperatively between the two groups. Results A total of 20 patients were studied: 6 in the GG and 14 in the PG. Mean residual aneurysm volume at 6 months postoperatively in the GG was 33.1% (±34.7), while that in the PG was 80.6% (±24.8) (P=0.018). A residual aneurysm volume of ≥35.2% at 6 months postoperatively was significantly associated with poor aneurysm obliteration at 1 year postoperatively (AUC=0.88, P=0.008). Conclusions Residual aneurysm volume percentage at 6 months after flow diverter stent treatment might be able to predict the likelihood of aneurysm occlusion at 1 year postoperatively.

Flow diverter surface modifications for aneurysm treatment: A review of the mechanisms and data behind existing technologies

Flow diversion (FD) has become a mainstay treatment for large wide-necked aneurysms. Despite excellent safety and efficacy, the risk of thromboembolic complications necessitates the use of dual antiplatelet therapy (DAPT). The use of DAPT makes hemorrhagic complications of stenting carry high morbidity and mortality. Additionally, DAPT usage carries a risk of "nuisance" complications that do not directly impact intracranial circulation but need to be managed nonetheless. To circumvent this issue, the most recent generation of flow diverters have undergone surface modification with various compounds to confer blood compatibility to limit clotting and thrombosis. While these newer generation flow diverters are marketed to enhance ease of deployment, the goal is to eventually facilitate single antiplatelet use with flow diverter treatment. This generation of FDs have potential to expand indications beyond unruptured wide-necked aneurysms to include ruptured intracranial aneurysms without the necessity of DAPT. Currently, no comprehensive review details the molecular mechanisms and pre-clinical and clinical data on these modifications. We seek to fill this gap in the literature by consolidating information on the coating technology for four major FDs currently in clinical use-PipelineTM Flex and Vantage Shield TechnologyTM, FREDTMX, p48/64 hydrophilic coating, and Acandis Dervio® 2heal-to serve as a reference guide in neurointerventional aneurysm treatment. Although the Balt silkTM was one of the first FDs, it is uncoated, thus we will not cover this device in our review. A literature review was performed to obtain information on each coating technology for the major flow diverters currently on the market using international databases (PUBMED, Embase, Medline, Google Scholar). The search criteria used the keywords for each coating technology of interest "phosphorylcholine," "poly 2-methoxyethyl acrylate," "hydrophilic polymer coating," and "fibrin-heparin" Keywords related to the device names "Pipeline Shield," "Pipeline Shield with Flex Technology," "FRED," "FREDX," "p64," "p64-HPC," "Derivo 2heal" were also used. Studies that detailed the mechanism of action of the coating, any pre-clinical studies with surface-modified intravascular devices, and any clinical retrospective series, prospective series, or randomized clinical trials with surface-modified devices for aneurysm treatment were included.

First clinical experience with the Derivo 2heal embolization device for the treatment of intracranial aneurysms

OBJECTIVE

The development of new flow-diverting devices with antithrombotic coatings may result in an improved safety profile, particularly a reduction in ischaemic stroke rates. The aim of this study was to evaluate our initial experience with the recently introduced coated Derivo® 2heal® Embolization Device (Acandis, Pforzheim, Germany).

METHODS

This is a retrospective, single-centre analysis of patients with intracranial aneurysms undergoing Derivo® 2heal® Embolization Device treatment. Patient and aneurysm characteristics, procedural parameters, complications, and degree of initial and short-term aneurysm occlusion were evaluated on an intention-to-treat basis.

RESULTS

A total of 16 unruptured aneurysms in 9 patients were treated with the Derivo® 2heal® Embolization Device in 10 treatment sessions. In one case the Derivo® 2heal® Embolization Device could not be deployed due to severe friction in the microcatheter. In all successful cases, one Derivo® 2heal® Embolization Device was sufficient to treat the target aneurysm and no additional coiling was performed. In-stent balloon angioplasty was performed in one procedure (10%) to improve vessel wall apposition. Twelve arterial side branches were covered in 9 procedures and all were patent at the end of the procedure. There were no clinical complications and no thromboembolic events during treatment. At the end of the procedure, contrast retention was observed in 13/16 (81%) aneurysms and at short-term follow-up, 6/9 (67%) were completely occluded.

CONCLUSIONS

The preliminary results of the new Derivo® 2heal® Embolization Device appear promising and warrant further evaluation by multicentre studies with long-term follow-up.