European Multicenter Study for the Evaluation of a Dual-Layer Flow-Diverting Stent for Treatment of Wide-Neck Intracranial Aneurysms: The European Flow-Redirection Intraluminal Device Study

Preliminary results of intracranial aneurysm treatment with derivo2heal embolization device

INTRODUCTION

The Derivo 2 Heal Embolization Device (D2HED) is a novel flow diverter (FD) providing a fibrin-/heparin-based surface coating aiming at lower thrombogenicity. We evaluate periprocedural aspects and preliminary aneurysm occlusion efficacy for intracranial aneurysm treatment.

METHODS

Thirty-four D2HEDs deployments (34 aneurysms, 32 patients) between 04/2021 and 10/2023 were analyzed. All patients were under dual antiplatelet therapy (dAPT). Periprocedural details, adverse events, and follow-up (FU) imaging were reviewed by consultant-level neuroradiologists. Complication rates and aneurysm occlusion efficacy are compared with performance data of other FDs based on literature research.

RESULTS

Each intervention succeeded in the deployment of one D2HED. Significant and/or increased intraaneurysmal contrast stagnation immediately after D2HED deployment was seen in 73.5% of cases according to O'Kelly-Marotta (OKM) grading scale. Clinically relevant early adverse events occurred in three patients: Among them two cases with fusiform aneurysms in the posterior circulation (ischemic events, early in-stent-thrombosis) and one patient (ischemic event) out of the majority of 31 treated internal carotid artery aneurysms (3,2%). Regarding mid-term FU (> 165 days), one aneurysm did not show progressive occlusion presumably caused by a prominent A1 segment arising from the terminal ICA aneurysm itself. Apart from that, mid-term complete / partial occlusion rates of 80% / 20% could be demonstrated.

CONCLUSION

Our case series - although suffering from restricted sample size - suggests a potential effectiveness of D2HED in managing intracranial aneurysms. Further studies with larger samples are warranted to quantify long-term occlusion efficacy and the impact of antithrombogenic surface coating on the necessary (d)APT.

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

BACKGROUND

Previous 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.

METHODS

A 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.

RESULTS

The 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.

CONCLUSION

FRED had high safety and efficacy in treating IAs, as evidenced by its high occlusion and low complication rates.

Comparison of pipeline embolization device and flow redirection endoluminal device in the treatment of intracranial aneurysms: A systematic review and meta-analysis

BACKGROUND

Advancements in flow diversion technology have revolutionized the treatment of intracranial aneurysms. The pipeline embolization device (PED) and the flow redirection endoluminal device (FRED) have emerged as prominent tools in this field. This study aims to compare the safety and efficacy profiles of PED and FRED in the treatment of intracranial aneurysms.

METHODS

Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive literature search was conducted across PubMed, Web of Science, and Scopus databases. Studies comparing PED and FRED were included and data extraction focused on study characteristics, patient demographics, and clinical and radiological outcomes. Primary outcomes were favorable outcomes, described as modified Rankin scale (mRS) 0-2 score, and complete/near-complete occlusion, while secondary outcomes included retreatment rate and thromboembolic and hemorrhagic complications.

RESULTS

Five studies, comprising 1238 patients, were included. No significant differences were found between PED and FRED in terms of complete occlusion at 6 months and 1 year, complete/near-complete occlusion at the last follow up, retreatment rates, and thromboembolic, in-stent thrombosis and hemorrhagic complications. However, FRED was significantly associated with higher favorable outcomes compared to PED (odds ratio: 0.37; confidence interval: 0.17 to 0.81; p = 0.01).

CONCLUSION

This study showed that both PED and FRED had comparable rates of complete occlusion, retreatment and complications, and FRED also demonstrated a higher likelihood of achieving favorable outcomes. The study underscores the need for further research with larger cohorts and longer follow up to consolidate these findings.

Flow Diversion for Endovascular Treatment of Intracranial Aneurysms: Past, Present, and Future Directions

Flow diversion for intracranial aneurysms emerged as an efficacious and durable treatment option over the last two decades. In a paradigm shift from intrasaccular aneurysm embolization to parent vessel remodeling as the mechanism of action, the proliferation of flow-diverting devices has enabled the treatment of many aneurysms previously considered untreatable. In this review, we review the history and development of flow diverters, highlight the pivotal clinical trials leading to their regulatory approval, review current devices including endoluminal and intrasaccular flow diverters, and discuss current and expanding indications for their use. Areas of clinical equipoise, including ruptured aneurysms and wide-neck bifurcation aneurysms, are summarized with a focus on flow diverters for these pathologies. Finally, we discuss future directions in flow diversion technology including bioresorbable flow diverters, transcriptomics and radiogenomics, and machine learning and artificial intelligence.

Comparison of pipeline embolization device and tubridge flow diverter for posterior circulation aneurysms: A multicentre propensity score matched study

Rationale and objectives

The off-label use of flow diverters (FDs) has broadened to include treating aneurysms in posterior circulation (PC). A novel flow diverter, the Tubridge flow diverter (TFD), has been created in China specifically for treating PC aneurysms. However, studies comparing between pipeline embolization device (PED) and TFD are rare. Thus, our study aimed to explore the effectiveness of PED and TFD in the treatment of PC aneurysms using a propensity score matched cohort design.

Methods

Retrospective data collection was conducted on patients who underwent treatment with either PED or TFD over the period from 2015 through 2020. Propensity score matching (PSM) was employed to calibrate for patient age; history of ischemic stroke; aneurysm size; morphology; location and neck; number of FDs; parent vessel diameter; and the employment of assisted coiling and balloon techniques. Data on previously ruptured aneurysms was not included in the analysis. A comparison was conducted between the two devices to assess perioperative complications, aneurysm occlusion rates, and functional outcomes.

Results

A total of 252 PC aneurysms were treated in 248 patients. Clinical and imaging follow-ups were lost in 26 and 47 patients, respectively. Major perioperative complications occurred in 7.5% of the cases, with favorable clinical outcomes in 91.0% and complete occlusion in 79.1%. Eighty-two (32.5%) aneurysms were treated with TFD, while 170 (67.5%) aneurysms were treated with PED. PSM was used to account for these significant variations, producing 82 matched pairs of unruptured aneurysms treated with PED or TFD. In terms of functional and angiographic outcomes, no significant differences were found between PED and TFD (functional outcome, p = 0.594 and angiographic outcome, p = 0.415). However, more perioperative major complications were found in patients treated with TFD (p = 0.005) compared with those receiving PED.

Conclusion

The comparative study of PED and TFD in the treatment of PC aneurysms resulted in positive clinical results and sustained occlusion rates, with acceptable perioperative complications. However, higher quality studies are needed to enhance our understanding of the use of FDs for treating of PC aneurysms.

Long-term Follow-up After Aneurysm Treatment with the Flow Redirection Endoluminal Device (FRED) Flow Diverter

INTRODUCTION

This study focuses on long-term outcomes after aneurysm treatment with either the Flow Re-Direction Endoluminal Device (FRED) or the FRED Jr. to investigate the durability of treatment effect and long-term complications.

METHODS

This study is based on a retrospective analysis of a prospectively maintained patient data base. Patients treated with either FRED or FRED Jr. between 2013 and 2017 at our institution, and thus a possibility for ≥ 5 years of follow-up, were included. Aneurysm occlusion rates, recurrence rates, modified Rankin scale score shifts to baseline, and delayed complications were assessed.

RESULTS

In this study 68 patients with 84 aneurysms had long-term follow-up with a mean duration of 57.3 months and 44 patients harboring 52 aneurysms had a follow-up ≥ 5 years with a mean follow-up period of 69.2 months. Complete occlusion was reached in 77.4% at 2 years and increased to 84.9% when the latest available imaging result was considered. Younger age and the absence of branch involvement were predictors for aneurysm occlusion in linear regression analysis. After the 2‑year threshold, there were 3 reported symptomatic non-serious adverse events. Of these, one patient had a minor stroke, one a transitory ischemic attack and one had persistent mass effect symptoms due to a giant aneurysm, none of these resulted in subsequent neurological disability.

CONCLUSION

This long-term follow-up study demonstrates that the FRED and FRED Jr. are safe and effective for the treatment of cerebral aneurysms in the long term, with high rates of complete occlusion and low rates of delayed adverse events.

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.

A Review of Current Flow Diverters

Flow diverter (FD) devices are new-generation stents placed in the parent artery at the aneurysmal neck to obstruct intra-aneurysmal blood flow, thus favoring intra-aneurysmal thrombosis. In Japan, about eight years have passed since health insurance approval was granted for FD devices, and FD placement to treat aneurysms has become widespread. Treatment indications have also been expanded with the introduction of novel devices. At present, three types of FD (Pipeline, FRED, and Surpass Streamline) are available in Japan. This report represents a compilation of available FD technologies and describes the current consensus on this treatment.

Flow Diversion for the Treatment of Intracranial Aneurysms in a Peruvian Cohort: Experiences from a Limited-Resource Setting and Barriers to Implementation

BACKGROUND

Stenting with flow diverter devices (FDDs) has increasingly emerged as a treatment for intracranial aneurysms. The use of FDDs in the developing world has not been described.

METHODS

A retrospective review was performed of a cohort of patients who underwent flow diversion at 4 tertiary-care centers in Lima, Peru between January 2017 and June 2021. Demographics, clinical features, and aneurysm morphology were evaluated. Clinical outcomes were observed 3 months after discharge and occlusion rates were assessed 12 months after treatment.

RESULTS

Sixty-nine patients (mean age, 46 ±14.5 years; 17% female) were treated with FDDs; 4% (n = 3) of the treated aneurysms were ruptured. Most aneurysms were saccular (n = 65; 94%), <10 mm in maximum size (n = 60; 87%), and located in the anterior circulation (n = 67; 97%). Minor complications, such as groin hematoma, occurred in 7 cases. No serious complications or deaths occurred. Patients' functional status was excellent (modified Rankin Scale score 0-1) in 99% (n = 66) at discharge and 100% (n = 67) at 3 months. Although some patients were lost to follow-up, complete occlusion was seen in 76% (n = 31) of 41 treated patients at 12 months.

CONCLUSIONS

We report the largest multicenter experience of FDDs for cerebral aneurysm treatment in Peru, with reasonable outcomes that are comparable to other settings despite various challenges, suboptimal circumstances, and lack of resources.

Retreatment with a pipeline embolization device for recanalized aneurysms following stent-assisted coiling embolization

Background and purpose

Flow diverters have emerged as viable alternatives for the retreatment of recanalized aneurysms following stent-assisted coiling embolization. In this study, we aim to present our experience of retreatment for such aneurysms using the pipeline embolization device (PED).

Materials and methods

This case series presents a retrospective single-center analysis of patients with recanalized aneurysms who underwent retreatment using the PED between July 2019 and April 2023, subsequent to stent-assisted coiling embolization.

Results

The study includes five female patients, whose relevant clinical data were recorded. All patients had aneurysms located in the internal carotid artery, comprising two blood blister-like aneurysms and two giant aneurysms. Prior to the retreatment, two LVIS stents, two enterprise stents, and one solitaire stent were implanted. Among the five patients, one experienced a fatal post-operative subarachnoid hemorrhage, while two patients achieved complete embolization, and another patient achieved near-complete embolization during the last follow-up. Furthermore, one patient faced challenges during the placement of the PED and was unable to achieve successful deployment. We propose four overlapping relationships between a newly implanted PED and a previously deployed stent: (1) PED covering only the proximal end of the previous stent, (2) PED covering only the distal end of the previous stent, (3) PED covering both the proximal and distal ends of the previous stent, and (4) PED deployed within the previous stent. Antiplatelet therapy at our center involved daily dual therapy with aspirin (100 mg/day) and clopidogrel (75 mg/day) for at least 5 days before PED placement. Intra-arterial bolus administration of tirofiban (5 mcg/kg) was administered during or immediately after PED deployment, followed by a maintenance dose of 0.08 mcg/kg/min IV infusion for at least 24-48 h if necessary. Postprocedural dual antiplatelet therapy included clopidogrel (75 mg/day) for 6 months and aspirin (100 mg/day) for 12 months.

Conclusion

The findings of this study support the efficacy of the PED for the retreatment of recanalized aneurysms following stent-assisted coiling embolization.

Safety and efficacy of the surpass streamline for intracranial aneurysms (SESSIA): A multi-center US experience pooled analysis

BACKGROUND AND PURPOSE

Flow diversion has established as standard treatment for intracranial aneurysms, the Surpass Streamline is the only FDA-approved braided cobalt/chromium alloy implant with 72-96 wires. We aimed to determine the safety and efficacy of the Surpass in a post-marketing large United States cohort.

MATERIALS AND METHODS

This is a retrospective multicenter study of consecutive patients treated with the Surpass for intracranial aneurysms between 2018 and 2021. Baseline demographics, comorbidities, and aneurysm characteristics were collected. Efficacy endpoint included aneurysm occlusion on radiographic follow-up. Safety endpoints were major ipsilateral ischemic stroke or treatment-related death.

RESULTS

A total of 277 patients with 314 aneurysms were included. Median age was 60 years, 202 (73%) patients were females. Hypertension was the most common comorbidity in 156 (56%) patients. The most common location of the aneurysms was the anterior circulation in 89% (279/314). Mean aneurysm dome width was 5.77 ± 4.75 mm, neck width was 4.22 ± 3.83 mm, and dome/neck ratio was 1.63 ± 1.26. Small-sized aneurysms were 185 (59%). Single device was used in 94% of the patients, mean number of devices per patient was 1.06. At final follow-up, complete obliteration rate was 81% (194/239). Major stroke and death were encountered in 7 (3%) and 6 (2%) cases, respectively.

CONCLUSION

This is the largest cohort study using a 72-96 wire flow diverter. The Surpass Streamline demonstrated a favorable safety and efficacy profile, making it a valuable option for treating not only large but also wide-necked small and medium-sized intracranial aneurysms.

Flow diversion for compressive unruptured internal carotid artery aneurysms with neuro-ophthalmological symptoms: a systematic review and meta-analysis

BACKGROUND

Data on the safety and efficacy of flow diverters (FD) for the treatment of unruptured internal carotid artery (ICA) aneurysms with compressive neuro-ophthalmological symptoms (NOS) are scarce and comprise mainly small case series.

METHODS

We performed a search of three databases and included series with ≥10 patients, with unruptured aneurysms of the ICA and NOS, treated with FD. Random-effects analysis of treatment results and safety was performed.

RESULTS

A total of 22 studies reporting on 594 patients were included. Pooled proportions of NOS recovery, improvement, transient and permanent worsening were: 47.4% (95% CI 35.0% to 60.1%); 74.5% (95% CI 67.9% to 80.2%); 7.1% (95% CI 3.3% to 14.7%); and 4.9% (95% CI 3.2% to 7.4%), respectively. Rates of complete recovery and improvement in patients with isolated visual symptoms were 30.6% (95% CI 12.5% to 57.7%) and 56.6% (95% CI 42.3% to 69.9%). Isolated oculomotor symptoms recovered completely in 47.8% (95% CI 29.9% to 66.3%) and improved in 78% (95% CI 69.2% to 84.9%). Morbidity occurred in 5% (95% CI 2.8% to 9%) and mortality in 3.9% (95% CI 2% to 7.5%) of patients. An increased likelihood of symptom improvement was observed when treatment was performed early (<1 month) after symptom onset (OR=11.22, 95% CI 3.9% to 32.5%).

CONCLUSION

Flow diversion promotes recovery or improvement of compressive symptoms in a large proportion of patients but is associated with significant rates of morbidity and mortality. Transient and permanent NOS worsening is not uncommon. Early treatment is of utmost importance, as it increases the likelihood of symptom improvement more than 10-fold.

Comparison of pipeline embolization device, flow re-direction endoluminal device and surpass flow diverters in the treatment of intracerebral aneurysms

OBJECTIVES

The use of flow diversion for the treatment of intracranial aneurysms has gained broad acceptance. Three flow-diverting stents are approved by the Food and Drug Administration for use in the United States. We sought to compare the outcomes and safety profiles between the three devices at our institution.

METHODS

A retrospective review of aneurysms treated with pipeline embolization device (PED), flow re-direction endoluminal device (FRED), and SURPASS was performed for aneurysms treated between 2018 and 2022 at our institution.

RESULTS

The study cohort consisted of 142 patients. Precisely, 86 aneurysms were treated with a pipeline, 33 aneurysms were treated with FRED, and 23 aneurysms were treated with SURPASS. The 1-year complete occlusion rates were 59.4%, 60%, and 65%, respectively (0.91). Linear regression models found that only adjunctive coiling predicted aneurysm occlusion at 6 months (p = 0.02), but this effect was lost at 1 year and beyond. There was no significant difference in acute thrombotic or acute hemorrhagic complications between the three cohorts. There was a higher rate of delayed hemorrhagic complications in the SURPASS cohort (10%) compared to the PED (1.3%) and FRED (0%) cohorts (p = 0.04). There was also a higher rate of in-stent stenosis in the SURPASS cohort (20%) compared to the PED (5%) and FRED (3.1%) cohorts (p < 0.01).

CONCLUSIONS

Treatment with PED, FRED, and SURPASS all resulted in similar complete occlusion rates at 6 months and 1 year. SURPASS was associated with higher in-stent stenosis as well as delayed hemorrhagic complications. Additional future studies evaluating the newest generation of flow-diverting stents with long-term follow-up will be necessary to make any definitive conclusions.

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

BACKGROUND AND PURPOSE

Flow diverters with antithrombotic coatings are increasingly used to improve the safety of flow diverter treatments of intracranial aneurysms. This study aimed to investigate the safety and short-term efficacy of the new FRED X flow diverter.

MATERIALS AND METHODS

Medical charts and procedural and imaging data of a consecutive series of patients with intracranial aneurysms who were treated with the FRED X at 9 international neurovascular centers were retrospectively analyzed.

RESULTS

One hundred sixty-one patients (77.6% women; mean age, 55 years) with 184 aneurysms (11.2% acutely ruptured) were included in this study. Most aneurysms were located in the anterior circulation (77.0%), most frequently at the ICA (72.7%). The FRED X was successfully implanted in all procedures. Additional coiling was performed in 29.8%. In-stent balloon angioplasty was necessary in 2.5%. The rate of major adverse events was 3.1%. Thrombotic events occurred in 7 patients (4.3%) with 4 intra- and 4 postprocedural in-stent thromboses, respectively (1 patient had both peri- and postprocedural thrombosis). Of these thrombotic events, only 2 (1.2%) led to major adverse events (ischemic strokes). Postinterventional neurologic morbidity and mortality were observed in 1.9% and 1.2%, respectively. The rate of complete aneurysm occlusion after a mean follow-up of 7.0 months was 66.0%.

CONCLUSIONS

The new FRED X is a safe and feasible device for aneurysm treatment. In this retrospective multicenter study, the rate of thrombotic complications was low, and the short-term occlusion rates are satisfactory.

Safety and efficacy of flow diverter stents in the treatment of middle cerebral artery aneurysms: a single-center experience and follow-up data

PURPOSE

This study aims to evaluate the safety and efficacy of flow diverters (FDs) in the treatment of middle cerebral artery (MCA) aneurysms and share the follow-up (F/U) results.

METHODS

The treatment and F/U results of 76 MCA aneurysms treated with the flow re-direction endoluminal device (FRED), FRED Jr., and pipeline embolization device (PED) FD stents were evaluated retrospectively. The aneurysm occlusion rates were compared between FDs, and the integrated and jailed branches were evaluated through follow-ups. The oversizing of the stent was compared between occluded/non-occluded aneurysms and integrated branches.

RESULTS

The mean F/U duration was 32 ± 6.3 months, and the mean aneurysm diameter was 4.45 mm. A total of 61 (80.3%) aneurysms were wide-necked; 73 (96.1%) were saccular; 52 (68.4%) were located at the M1 segment; and 36 (45.6%) FREDs, 23 (29.1%) FRED Jr.s, and 19 (24.1%) PEDs were used for treatment. The overall occlusion rates for the 6-, 12-, 24-, 36-, and 60-month digital subtraction angiographies were 43.8%, 63.5%, 73.3%, 85.7%, and 87.5% respectively. The last F/U occlusion rates were 67.6% for FRED, 66.7% for PED, and 60.6% for FRED Jr. (P = 0.863). An integrated branch was covered with an FD during the treatment of 63 (82.8%) aneurysms. A total of six (10%) of the integrated branches were occluded without any symptoms at the last F/U appointment. The median oversizing was 0.45 (0-1.30) for occluded aneurysms, and 0.50 (0-1.40) for non-occluded aneurysms (P = 0.323). The median oversizing was 0.70 (0.45-1.10) in occluded integrated branches and 0.50 (0-1.40) in non-occluded branches (P = 0.131). In-stent stenosis was seen in 22 (30.1%) of the stents at the 6-month F/U and in only 2 (4.7%) at the 24-month F/U. Thus, none of the patients had any neurological deficits because of the in-stent stenosis. Severe in-stent stenosis was seen in two stents.

CONCLUSION

MCA aneurysms tend to be complex, with integrated branches and potentially wide necks. FD stents are safe and effective in the treatment of MCA aneurysms, and the patency of the side and jailed branches is preserved in most cases. Higher occlusion and lower in-stent stenosis rates are seen with longer F/U durations.

Endovascular treatment of unruptured intracranial aneurysms with flow diverters: A retrospective long-term single center analysis

PURPOSE

The introduction of flow diverters (FDs) in 2007 greatly enhanced the treatment of intracranial aneurysms. Here, we present our long-term clinical experience in treating unruptured intracranial aneurysms with FDs.

METHODS

107 patients with unruptured aneurysms and treated with an FD between 2010 and 2019 were retrospectively reviewed. Aneurysm occlusion, procedural complications, and clinical outcome were evaluated.

RESULTS

Angiographic follow-up was available for 93 patients with a mean long-term follow-up time of 28.4 ± 21.6 months. Additional coiling was performed in 15.1% of patients (n = 14). Adequate aneurysm occlusion (Kamran grades 3 and 4) at long-term follow-up was achieved in 94.6% of patients (n = 88). 3.2% (n = 3) required endovascular retreatment since the last follow-up showed a lack of aneurysm occlusion (Kamran grade 0) due to a foreshortening of the FD. Incomplete opening of the FD and parent vessel occlusion was seen in 1.1% (n = 1) and 3.2% (n = 3) of patients, respectively. In-stent stenosis was observed in 57% (n = 53) of cases at short-term follow-up and 22.6% (n = 21) at long-term, which were moderate and asymptomatic overall. In-stent stenosis decreased significantly between short- and long-term follow-ups (31.4 ± 17.0% vs 9.7 ± 13.6%, respectively; p ≤ 0.001). Thromboembolic and hemorrhagic events occurred in 7.5% (n = 7) and 1.1% (n = 1) of patients, respectively. Good clinical outcome (modified Rankin scale: 0-2) was obtained in 97.8% (n = 91) leading to an overall treatment-related morbidity of 2.2% (n = 2). There was no procedural mortality.

CONCLUSION

Our study shows that FD treatment of unruptured intracranial aneurysms is effective and safe with high occlusion rates and low rates of permanent morbidity at long-term follow-up.

Comparison of Flow-Redirection Endoluminal Device and Pipeline Embolization Device in the Treatment of Intracerebral Aneurysms

BACKGROUND

The use of flow diverters for treating intracranial aneurysms has been widely used in the past decade; however, data comparing pipeline embolization device (PED; Medtronic Inc) and flow-redirection endoluminal device (FRED; MicroVention) in the treatment of intracranial aneurysms remain scarce.

OBJECTIVE

To compare the outcomes of PED and FRED in the treatment of intracranial aneurysms.

METHODS

This is a single-center retrospective review of aneurysms treated with PED and FRED devices. Patients treated with PED or FRED were included. Cases requiring multiple or adjunctive devices were excluded. Primary outcome was complete aneurysm occlusion at 6 months. Secondary outcomes included good functional outcome, need for retreatment, and any complication.

RESULTS

The study cohort comprised 150 patients, including 35 aneurysms treated with FRED and 115 treated with PED. Aneurysm characteristics including location and size were comparable between the 2 cohorts. 6-month complete occlusion rate was significantly higher in the PED cohort (74.7% vs 51.5%; P = .017) but lost significance after inverse probability weights. Patients in the PED cohort were associated with higher rates of periprocedural complications (3.5% vs 0%; P = .573), and the rate of in-stent stenosis was approximately double in the FRED cohort (15.2% vs 6.9%; P = .172).

CONCLUSION

Compared with PED, FRED offers modest 6-month occlusion rates, which may be due to aneurysmal and baseline patient characteristics differences between both cohorts. Although not significant, FRED was associated with a higher complication rate mostly because of in-stent stenosis. Additional studies with longer follow-up durations should be conducted to further evaluate FRED thrombogenicity.

The DERIVO®2 Embolization Device in the treatment of ruptured and unruptured intracranial aneurysms: A multicenter analysis

BACKGROUND

Flow diverters are an increasingly used treatment option for intracranial aneurysms. A recent addition to the European market is the DERIVO®2 Embolization Device (DED2), promising improved radiopacity. We aimed to assess the safety and efficacy of the DED2 regarding angiographic and clinical outcomes in ruptured and unruptured cerebral aneurysms.

METHODS

We performed a multicenter trial at six interventional centers. Data were prospectively collected and all patients treated with the DED2 were included. The primary endpoint was angiographic aneurysm occlusion at 6 months as assessed by the O'Kelly Marotta (OKM) grading scale with a favorable outcome definition of OKM C + D. Clinical outcome was evaluated according to the modified Rankin scale (mRS).

RESULTS

Between August 2020 and July 2021, 37 patients were treated with the DED2 and were included in our analysis. Five patients presented with ruptured aneurysms. Median age was 60 years, 27 patients were female, and 10 male. Median mRS was 0 (range 0-4). Mean aneurysm size was 8.9 ± 7.1 mm with a mean neck size of 6.5 ± 6.1. The DED2 fully opened at deployment in all cases. Clinical follow-up was available for 30 patients (81%). Twenty-five (83%) had an mRS of 0 or 1. Three patients with ruptured aneurysms died during the follow-up period. No treatment-related major morbidity was observed. Follow-up imaging was available in 27 (90%) patients, with 23 patients (85%) showing satisfactory aneurysm occlusion OKM grade C-D.

CONCLUSION

In this small cohort, the DED2 provided safe and effective treatment of ruptured and unruptured intracranial aneurysms.

Delayed aneurysm rupture in a patient treated with flow redirection endoluminal device: A case report and literature review

Background:

Delayed aneurysm rupture after flow-redirection endoluminal device (FRED) implantation is rare. We report a case of internal carotid-cavernous fistula (CCF) caused by a delayed aneurysm rupture of the cavernous portion of the internal carotid artery (ICA) after FRED implantation.

Case Description:

A 75-year-old woman had a gradually enlarging aneurysm at the C4 portion of the left ICA. We performed FRED implantation for the same. The FRED implantation procedure was smooth and the FRED expanded well and attached to the vessel wall. Five days after surgery, the patient developed a strong headache, hyperemia of the left eye, and disturbance of the left eye movement. Magnetic resonance imaging and angiography revealed a left CCF with cortical venous reflux. We performed transarterial aneurysmal and transvenous cavernous sinus embolization. Postoperatively, angiography showed no fistula and complete occlusion of the aneurysm; however, minor eye movement disorder persisted.

Conclusion:

To prevent the development of delayed aneurysm rupture in patients treated with FRED, preoperative consideration of whether to add coil embolization is important, even if the aneurysm is located in the C4 portion of the ICA and there is no risk of subarachnoid hemorrhage, including the size of aneurysm. In this report, we have tried to alert surgeons regarding the risk of delayed aneurysm rupture due to FRED implantation.

North American multicenter experience with the Flow Redirection Endoluminal Device in the treatment of intracranial aneurysms

OBJECTIVE

Flow diverters have revolutionized the endovascular treatment of intracranial aneurysms. Here, the authors present the first large-scale North American multicenter experience using the Flow Redirection Endoluminal Device (FRED) in the treatment of cerebral aneurysms.

METHODS

Consecutive cerebral aneurysms treated with FRED at 7 North American centers between June 2020 and November 2021 were included. Data collected included patient demographic characteristics, aneurysm characteristics, periprocedural and long-term complications, modified Rankin Scale (mRS) scores, and radiological follow-up.

RESULTS

In total, 133 aneurysms in 116 patients were treated with 123 FRED deployment procedures and included in this study. One hundred twenty-six aneurysms (94.7%) were unruptured, 117 (88.0%) saccular, and 123 (92.5%) located in anterior circulation. The mean (range) aneurysm maximal width and neck width sizes were 7.2 (1.5-42.5) mm and 4.1 (1.0-15.1) mm, respectively. Successful FRED deployment was achieved in 122 procedures (99.2%). Adjunctive coiling was used in 4 procedures (3.3%). Radiological follow-up was available for 101 aneurysms at a median duration of 7.0 months. At last follow-up, complete occlusion was observed in 55.4% of patients, residual neck in 8.9%, and filling aneurysm in 35.6%; among cases with radiological follow-up duration > 10 months, these values were 21/43 (48.8%), 3/43 (7.0%), and 19/43 (44.2%), respectively. On multivariate regression analysis, age (OR 0.93, p = 0.001) and aneurysm neck size (OR 0.83, p = 0.048) were negatively correlated with odds of complete occlusion at latest follow-up. The retreatment rate was 6/124 (4.8%). The overall complication rate was 31/116 (26.7%). Parent vessel occlusion, covered branch occlusion, and in-stent stenosis were detected in 9/99 (9.1%), 6/63 (9.5%), and 15/99 (15.2%) cases, respectively. The FRED-related, symptomatic, thromboembolic, and hemorrhagic complication rates were 22.4%, 12.9%, 6.9%, and 0.9% respectively. The morbidity rate was 10/116 patients (8.6%). There was 1 death due to massive periprocedural internal carotid artery stroke, and 3.6% of the patients had an mRS score > 2 at the last follow-up (vs 0.9% at baseline).

CONCLUSIONS

As the first large-scale North American multicenter FRED experience, this study confirmed the ease of successful FRED deployment but suggested lower efficacy and a higher rate of complications than reported by previous European and South American studies on FRED and other flow-diverting devices. The authors recommend judicious use of this device until future studies can better elucidate the long-term outcomes of FRED treatment.

Shape Memory Polymer-Based Endovascular Devices: Design Criteria and Future Perspective

Devices for the endovascular embolization of intracranial aneurysms (ICAs) face limitations related to suboptimal rates of lasting complete occlusion. Incomplete occlusion frequently leads to residual flow within the aneurysm sac, which subsequently causes aneurysm recurrence needing surgical re-operation. An emerging method for improving the rates of complete occlusion both immediately after implant and in the longer run can be the fabrication of patient-specific materials for ICA embolization. Shape memory polymers (SMPs) are materials with great potential for this application, owing to their versatile and tunable shape memory properties that can be tailored to a patient’s aneurysm geometry and flow condition. In this review, we first present the state-of-the-art endovascular devices and their limitations in providing long-term complete occlusion. Then, we present methods for the fabrication of SMPs, the most prominent actuation methods for their shape recovery, and the potential of SMPs as endovascular devices for ICA embolization. Although SMPs are a promising alternative for the patient-specific treatment of ICAs, there are still limitations that need to be addressed for their application as an effective coil-free endovascular therapy.

The Pennsylvania Postmarket Multicenter Experience With Flow Redirection Endoluminal Device

BACKGROUND

The flow redirection endoluminal device (FRED) is a novel self-expanding double-layer nitinol braided flow diverter that recently received FDA approval. However, early postmarket studies from the United States are lacking.

OBJECTIVE

To report our short-term multicenter experience.

METHODS

Series of consecutive patients undergoing FRED treatment for intracranial aneurysms were queried from prospectively maintained registries at 4 North-American Centers in Pennsylvania (February 2020-June 2021). The pertinent baseline demographics, aneurysmal characteristics, and procedural outcomes were collected and analyzed, with primary outcome of aneurysmal occlusion and secondary outcome of safety and complications.

RESULTS

Sixty-one patients (median age 58 years, 82% female) underwent 65 FRED treatment procedures for 72 aneurysms. Most (86.1%) of the aneurysms were unruptured; 80.5% were saccular in morphology, and 87.5% were located along the internal carotid artery, with a median size of 7.1 mm (IQR 5.2-11.9 mm). Radiographic follow-up was available in 86.1% of the aneurysms, showing complete occlusion in 74.2% (80% in catheter angiography-only group), and near-complete occlusion in 11.3% of the cases (median 6.3 months), with 2.8% re-treated. Permanent ischemic complications were encountered in 2.8% of the cases, with no procedural mortality. A modified Rankin Scale of 0 to 2 was documented in 98.1% of the patients at the last clinical follow-up (median 6.1 months).

CONCLUSION

The results of the early postmarket experience with the FRED device show reasonable safety and adequate aneurysmal occlusion rates comparable with other flow diverters. However, more extensive multicenter studies with more extended follow-up data are needed to assess the long-term safety and durability of the device.

Staged Hybrid Techniques With Straightforward Bypass Surgery Followed by Flow Diverter Deployment for Complex Recurrent Middle Cerebral Artery Aneurysms

Background

Recurrent complex middle cerebral artery (MCA) aneurysms after combined clipping and endovascular surgery are challenging, and if conventional techniques are adapted, advanced surgical, endovascular, and a combination of both techniques are often required. For such complex aneurysms, safe and effective straightforward techniques for all neurovascular surgeons are warranted. We describe the details of staged hybrid techniques with straightforward bypass surgery followed by flow diverter deployment in a patient with complex MCA aneurysm.

Illustrative Case

A 69-year-old woman presented with left recurrent large MCA aneurysm enlargement 25 years after direct surgery and coil embolization for ruptured aneurysm. The recurrent MCA aneurysm had large and complex morphology and was adhering to the brain tissues. Therefore, it was unsuitable to treat such aneurysm with conventional surgical and endovascular techniques with a high risk of morbidity. We performed (1) M2 ligation following superficial temporal artery-M2 bypass and (2) flow diverter deployment assisted with coil packing in two sessions. Three months after the second session, the aneurysm was completely occluded with endothelialization of the neck. Angiographic findings revealed no recurrence 12 months after the treatment.

Conclusions

Staged hybrid techniques with straightforward bypass surgery followed by flow diverter deployment may be a safe and effective treatment for complex recurrent MCA aneurysms.

Comprehensive review of the recent advances in devices for endovascular treatment of complex brain aneurysms

The International Subarachnoid Aneurysm Trial (ISAT) showed superiority for endovascular treatment of ruptured aneurysms and technology has since moved on rapidly. Many approaches and technology now exist for the endovascular management of ruptured and unruptured intracranial aneurysms, which reflects their varied nature - there is no one-size-fits-all technique. We aim to provide an overview of the various classes of device and the major developments over the past decade. Coiling is the oldest of the technology and continues to demonstrate high levels of occlusion and acceptable risks, making it the default treatment choice, particularly in the acutely ruptured aneurysm setting. Advances on coiling include the use of adjuncts such as balloons, stents and fully retrievable temporary neck-bridging devices, which have facilitated the treatment of more complex aneurysms. Flow divertors have also revolutionised complex aneurysm treatment with small added risk in acute aneurysm treatment and seek to remodel the aneurysm-vessel interface without accessing the aneurysm sac. The latest development and most promising avenue appears to be intrasaccular flow disrupting devices like WEB, Contour and Neqstent that provide excellent opportunities to treat wide neck complex aneurysm with minimal mortality and morbidity and good occlusion rates and may in future replace a significant number of stent-assisted coiling too.

Microsnare Retrieval of a Distorted Flow Re-direction Endoluminal Device (FRED)

Retained endovascular devices are becoming increasingly reported as the indications for endovascular intervention continue to expand. As such, an interventionalist needs to be prepared to extract devices that are improperly deployed. This case illustrates the successful retrieval of an incompletely opened flow diverting stent using a microsnare. This is the second reported case of this complication and the first known case specific to the flow re-direction endoluminal device (FRED; Microvention, Aliso Viejo, California, USA).

Efficacy of the Flow Re-direction Endoluminal Device for cerebral aneurysms and causes of failed deployment

Purpose

The Flow Re-direction Endoluminal Device (FRED) has recently become available for flow diversion in Japan. We have encountered cases that failed to deploy the FRED. In this study, we report our initial experience with the FRED for cerebral aneurysms and clarify the causes of failed FRED deployment.

Methods

A retrospective data analysis was performed to identify patients treated with the FRED between June 2020 and March 2021. Follow-up digital subtraction angiography was performed at 3 and 6 months and assessed using the O’Kelly-Marotta (OKM) grading scale.

Results

Thirty-nine aneurysms in 36 patients (average age: 54.4 years) were treated with the FRED. The average sizes of the dome and neck were 9.9 mm and 5.2 mm, respectively. In nine patients, additional coiling was performed. In one patient (2.6%), proximal vessel injury caused direct carotid-cavernous fistula during deployment. Ischaemic complications were encountered in one patient (2.6%) with transient symptoms. Angiographic follow-up at 6 months revealed OKM grade C or D in 86.6% of patients. FRED deployment was successful in 35 (92.1%) procedures. In the failure group, the differences between the FRED and the minimum vessel diameter (P = 0.04) and the rate of the parent vessel having an S-shaped curve (P = 0.04) were greater than those in the success group.

Conclusions

Flow diversion using the FRED is effective and safe for treating cerebral aneurysms. The use of the FRED for patients with an S-shaped curve in the parent vessel and oversizing of more than 2 mm should be considered carefully.

Long-term results and comparison of flow re-direction endoluminal device and pipeline embolization device in endovascular treatment of intracranial carotid aneurysms

OBJECTIVE

This study aims to compare the efficacy, safety, and long-term outcomes of two flow diverters, i.e., pipeline embolization device and flow re-direction endoluminal device, in the treatment of distal carotid aneurysms.

METHODS

A total of 138 patients with 175 aneurysms were included from February 2012 to September 2019. Ninety-nine aneurysms were treated with flow re-direction endoluminal device and 76 with pipeline embolization device. Angiographic follow-ups were at the 6th, 12th, 24th, 36th, and 60th months; the O'Kelly-Marotta grading scale was used to assess aneurysms occlusion. Outcomes of two devices were compared; possible associations regarding patient characteristics, aneurysm properties, treatment details, and adverse events were evaluated.

RESULTS

The mean follow-up period was 33 months, with 10 patients lost to follow-up. Occlusion rates at the 6th and 12th months and during the last follow-up were similar for flow re-direction endoluminal device (81%, 84%, and 90%) and pipeline embolization device (82%, 85%, and 93%). Occlusion rates were also similar after stand-alone use without coiling. There was no significant difference regarding adverse event rates with a 10.9% overall complication rate, 3.6% mortality, and 0.7% permanent morbidity. All the mortality and morbidity were related to hemorrhagic complications. Device deployment failure was observed with five flow re-direction endoluminal devices and two pipeline embolization devices, whereas two severe in-stent stenoses occurred with each device.

CONCLUSIONS

Both flow re-direction endoluminal device and pipeline embolization device are feasible and effective in flow diversion of distal internal carotid artery aneurysms, with similar adverse events rates and aneurysm occlusion success. Aneurysm occlusion rates increase with time, while the presence of an integrated branch significantly decreases treatment success.

Implantation of Large Diameter (5.5-6 mm) Derivo Embolization Devices for the Treatment of Cerebral Aneurysms

BACKGROUND

The efficacy of flow diverters is dependent upon robust wall apposition in the parent artery. Usage in large caliber cerebral vessels has therefore been limited as few implants with diameters > 5 mm exist. We present our initial experience in treating cerebral aneurysms using the 5.5 mm and 6 mm diameter implants of the Derivo embolization device (DED).

METHODS

Our prospectively maintained institutional database was reviewed to identify patients in whom a > 5 mm DED was implanted between November 2016 and February 2021. The primary efficacy outcome was complete or near-complete aneurysm occlusion at 6 months (O'Kelly-Marotta, OKM, C-D, adapted for magnetic resonance angiography). Safety outcomes included 30-day major morbidity defined as modified Rankin Score (mRS) 3-5, mortality, serious adverse events and procedural complications.

RESULTS

A total of 21 large diameter DEDs were deployed in 18 patients (age 59.5 ± 14.1 years), harboring 19 unruptured aneurysms. Of the aneurysms 14 (73.7%) were saccular in morphology (sac diameter 10.9 ± 5.5 mm, neck diameter 6.8 ± 3.1 mm), 3 (15.8%) aneurysms were dissecting, 1 (5.3%) iatrogenic pseudoaneurysm and 1 (5.3%) fusiform. Aneurysm locations were: ICA (internal carotid artery) (n = 17); (7 cavernous, 4 paraophthalmic, 2 paraclinoid, 1 petrous, 2 communicating, 1 cervical); vertebrobasilar (n = 2). Adjunct stenting to optimize proximal wall apposition was undertaken in 5 (27.8%) patients. At 6 months 75% of patients followed-up met the primary efficacy endpoint (OKM C-D). There were no serious adverse events, 30-day major morbidity (mRS 3-5) or mortality.

CONCLUSION

Implantation of large diameter (5.5 mm and 6 mm) DEDs into capacious cerebral vessels to treat a range of complex aneurysms is safe and technically feasible but may require adjunct stenting to optimize proximal wall apposition. Short-term efficacy of this device subset is comparable to previous DED and other flow diverter studies. Long-term follow-up and comparative studies are required for further assessment.

REtrospective Multicenter INdian Study of Derivo Embolization Device (REMIND): Periprocedural Safety

Purpose

The treatment of aneurysms with characteristics such as complex morphology, fusiform, blister-like, wide neck, or large size has been revolutionized with the introduction of flow diverters. Though flow diverters have several advantages over coiling, they also have certain important disadvantages such as the lack of immediate protection against rupture, the risk of ischemic stroke, the need for antiplatelet therapy, and long latency for complete effect. The Derivo Embolization Device (DED) is a second-generation self-expanding device that is claimed to be less thrombogenic than conventional devices. We retrospectively evaluated the periprocedural safety and risks associated with the DED across 5 centers in India.

Materials and Methods

This is a multicentric, retrospective, observational study of DED, conducted at 5 high volume endovascular therapy centers in India from May 2018 to June 2020. Periprocedural demographic, clinical, and angiographic data were collected from a retrospective review of patient charts.

Results

A total of 96 patients, including 56 (58.3%) females, aged between 16–80 years (60±12.7 years) harboring 106 aneurysms were studied. Seven (7.3%) were noted to harbor multiple aneurysms: 6 had 3 aneurysms each, while 1 patient had 5 aneurysms. The following aneurysm characteristics were noted: average size, 9.8±8.2 mm; average neck size, 6.9±8.5 mm; wide-necked (>4 mm), 63 (59.4%); giant (>25 mm), 8 (7.5%); and anterior circulation location, 98 (92.5%). Eighteen (17%) of these were ruptured. Additional balloon angioplasty was performed in 5 (5.2%) patients. Intraprocedural problems were encountered in 3 (3.1%), of which only 1 had clinical implications, the device fish-mouthing with stent thrombosis resulting in a malignant middle cerebral artery territory infarction. The modified Rankin scale at 3 months was worse in 1 patient.

Conclusion

DED is a newer generation flow diverter stent with a low periprocedural complication rate.

Flow Redirection Endoluminal Device (FRED) with or without Adjunctive Coiling in Treatment of Very Large and Giant Cerebral Aneurysms

PURPOSE

Flow diverter stents are gaining wider use in the treatment of complex intracranial aneurysms; however, there are limited data on occlusion and complication rates of flow diverters in very large and giant aneurysms. This study assessed the safety and efficacy of flow redirection endoluminal device (FRED) and FRED Jr. stents in aneurysms ≥ 20 mm.

METHODS

We retrospectively analyzed all aneurysms ≥ 20 mm treated with FRED/FRED Jr. between January 2010 and June 2020 from three centers. Endpoints for clinical safety were absence of major stroke, aneurysmal rupture, or death and complete or near-complete occlusion for efficacy.

RESULTS

A total of 45 patients with very large (28 cases) and giant aneurysms (17 cases) were treated with FRED (41 cases), and FRED Jr. (4 cases) stents. The majority of the aneurysms (40/45, 88.9%) were in the anterior circulation. Adjunctive aneurysm coiling was performed in 21 aneurysms (46.7%). Technical complications were encountered in 4 procedures (8.9%). Ischemic and hemorrhagic complication rates were 6.7% and 8.9%, respectively. There was no case with major stroke. The mortality rate was 8.9%, and all cases were due to hemorrhagic complications from aneurysmal rupture. Median angiographic follow-up was 21.5 months (range 3-60 months). Complete occlusion was achieved in 32 aneurysms (71.1%), and near-complete occlusion in 5 cases (11.1%).

CONCLUSION

The use of FRED/FRED Jr. for the treatment of aneurysms ≥ 20 mm achieved a long-term aneurysm occlusion rate and a safety profile comparable to the large series reported with other flow diverter stents.

Safety and efficacy results of the Flow Redirection Endoluminal Device (FRED) stent system in the treatment of intracranial aneurysms: US pivotal trial

OBJECTIVE

To evaluate the safety and effectiveness of the Flow Redirection Endoluminal Device (FRED) flow diverter in support of an application for Food and Drug Administration approval in the USA.

METHODS

145 patients were enrolled in a prospective, single-arm multicenter trial. Patients with aneurysms of unfavorable morphology for traditional endovascular therapies (large, wide-necked, fusiform, etc) were included. The trial was designed to demonstrate non-inferiority in both safety and effectiveness, comparing trial results with performance goals (PGs) established from peer-reviewed published literature. The primary safety endpoint was death or major stroke (National Institutes of Health Stroke Scale score ≥4 points) within 30 days of the procedure, or any major ipsilateral stroke or neurological death within the first year. The primary effectiveness endpoint was complete occlusion of the target aneurysm with ≤50% stenosis of the parent artery at 12 months after treatment, and in which an alternative treatment of the target intracranial aneurysm had not been performed.

RESULTS

145 patients underwent attempted placement of a FRED device, and one or more devices were placed in all 145 patients. 135/145 (93%) had a single device placed. Core laboratory adjudication deemed 106 (73.1%) of the aneurysms large or giant. A safety endpoint was experienced by 9/145 (6.2%) patients, successfully achieving the safety PG of <15%. The effectiveness PG of >46% aneurysm occlusion was also achieved, with the effectiveness endpoint being met in 80/139 (57.6%) CONCLUSION: As compared with historically derived performance benchmarks, the FRED flow diverter is both safe and effective for the treatment of appropriately selected intracranial aneurysms.

CLINICAL REGISTRATION NUMBER

NCT01801007.

Flow redirection endoluminal device (FRED) for treatment of intracranial aneurysms: A systematic review

INTRODUCTION

The Flow Redirection Endoluminal Device (FRED; MicroVention) is a dual-layered flow diverter used for the treatment of intracranial aneurysms. The objective of this systematic review was to compile device-related safety and effectiveness data.

METHODS

The literature from January 1, 2013 to April 30, 2021 was searched for studies describing use of the FRED for intracranial aneurysm treatment irrespective of aneurysm location and morphology. The review included anterior and posterior circulation ruptured and unruptured saccular, fusiform or dissection, and blister aneurysms. MeSH terms related to "flow re-direction endoluminal device" and "FRED for aneurysms" were used. Data related to indication, complications, and rates of aneurysm occlusion were retrieved and analyzed.

RESULTS

Twenty-two studies with 1729 intracranial aneurysms were included in this review. Overall reported morbidity was 3.9% (range 0-20%). Overall procedure-related mortality was 1.4% (range 0-6%). Complication rates fell into 5 categories: technical (3.6%), ischemic (3.8%), thrombotic or stenotic (6%), hemorrhagic (1.5%), and non-neurological (0.8%). The aneurysm occlusion rate between 0 and 3 months (reported in 11 studies) was 47.8%. The occlusion rate between 4 and 6 months (reported in 14 studies) was 73.8%. Occlusion rates continued to increase to 75.1% at 7-12 months (reported in 10 studies) and 86.6% for follow-up beyond 1 year (reported in 10 studies).

CONCLUSION

This review indicated that the FRED is a safe and effective for the treatment of intracranial aneurysms. Future studies should directly compare the FRED with other flow diverters for a better understanding of comparative safety and effectiveness among the different devices.

Evaluation of a novel flow diverter, the DiVeRt system, in an animal model

BACKGROUND

Using a surgical aneurysm model, this study assessed the performance of a new flow diverter (FD), the DiVeRt, and evaluated the angiographic and histologic features at different periods after stent deployment.

METHODS

Fifteen New Zealand White rabbits were treated 3 days prior to intervention and until euthanization with dual antiplatelets. DiVeRt was implanted in bilateral carotid aneurysms (n=30) as well as in the aorta (n=15). The rate of technical success, assessment of aneurysm occlusion (measured by the O'Kelly-Marotta grading (OKM) scale), and stent patency were examined using angiography and histologic examinations in three groups at 1, 3, and 6 months follow-up (FU). In each FU group one control animal was included and treated with the XCalibur stent (n=3).

RESULTS

Overall, DiVeRt placement was successful and without apparent intraprocedural complications. In total, four stents in the carotid artery were occluded and in-stent stenosis was registered in two carotid (7%) and one aortic (6%) vessels. Complete or near complete aneurysm occlusion (OKM scale D1 and C3) was seen in 100% in the 1-month FU group, 70% in the 2-month FU group, and 100% in the 3-month FU group. Histology showed loose, organizing fibrous tissue matrix within the sac and adequate neck endothelialization in all vessels. All branches covered by the DiVeRt remained patent.

CONCLUSIONS

The DiVeRt system appears to be feasible and effective for the treatment of aneurysms with high rates of complete aneurysm occlusion, excellent vessel patency, and evidence of high biocompatibility. Occurrences of parent artery occlusion at follow-up did not result in clinical consequences.

Endovascular Treatment of Anterior Circulation Aneurysms With the p64 Flow Modulation Device: Mid- and Long-Term Results in 617 Aneurysms From a Single Center

BACKGROUND

Flow diverters have become an important tool in the treatment of intracranial aneurysms, especially when dealing with difficult-to-treat or complex aneurysms. The p64 is the only fully resheathable and mechanically detachable flow diverter available for clinical use.

OBJECTIVE

To evaluate the safety and effectiveness of p64 for the treatment of intracranial saccular unruptured aneurysms arising from the anterior circulation over a long-term follow-up period.

METHODS

We retrospectively reviewed our prospectively maintained database to identify all patients who underwent treatment for an intracranial saccular (unruptured or beyond the acute hemorrhage phase) aneurysm arising from the anterior circulation with ≥1 p64 between December 2011 and December 2019. Fusiform aneurysms and dissections were excluded. Aneurysms with prior or concomitant saccular treatment (eg, coiling and clipping) were included. Aneurysms with parent vessel implants other than p64 were excluded. Anatomic features, intraprocedural complications, clinical outcome, as well as clinical and angiographic follow-ups were all recorded.

RESULTS

In total, 530 patients (388 females; median age 55.9 yr) with 617 intracranial aneurysms met the inclusion criteria. The average number of devices used per aneurysm was 1.1 (range 1-3). Mean aneurysm dome size was 4.8 mm (range 1-27 mm). Treatment-related morbimortality was 2.4%. Early, mid-term, and long-term angiographic follow-up showed complete or near-complete aneurysm occlusion in 76.8%, 89.7%, and 94.5%, respectively.

CONCLUSION

Treatment of intracranial saccular unruptured aneurysms of the anterior circulation using p64 is a safe and effective treatment option with high rate of occlusion at long-term follow-up and low morbimortality.

Whether Intracranial Aneurysm Could Be Well Treated by Flow Diversion: A Comprehensive Meta-Analysis of Large-Sample Studies including Anterior and Posterior Circulation

BACKGROUND

Flow diversion (FD) has become a widely adopted treatment method for intracranial aneurysms in the clinic, but a comprehensive meta-analysis of large-sample studies including anterior and posterior circulation is still lacking.

METHODS

The PubMed, Embase, Web of Science, and Cochrane databases were searched between January 1, 2008, and December 1, 2019. A random-effect model was used to calculate the efficacy and safety data as well as 95% confidence intervals (CIs).

RESULTS

The pooled sample size of all included studies was 6695 patients; the mean age was 55.5 years old, with a total of 7406 aneurysms. For efficacy, the complete occlusion rate in angiographic follow-up (AFU) at 6 months was 78% (95% CI, 0.77, 0.80), and the AFU rate at 6-12 months was 90% (95% CI, 0.88, 0.92). For safety, the hemorrhagic event rate was 2%, the ischemic event rate was 5%, and the mortality rate was 3%.

CONCLUSION

FD is an effective and safe treatment for intracranial aneurysm with high complete occlusion rate and acceptable complication rate.

The new generation double layered flow diverters for endovascular treatment of intracranial aneurysms: current status of ongoing clinical uses

INTRODUCTION

The treatment of intracranial aneurysms has significantly evolved over the last decade with the advancement in endovascular techniques and devices. Flow diverters are the latest in the armamentarium for vascular reconstruction, aneurysm exclusion, and preservation of branch vessels. The possibility of treating various types of intracranial aneurysms, including those previously considered untreatable, has represented a new paradigm in the neurovascular era.

AREAS COVERED

This paper describes in detail the current status in the use of new generation double-layered Flow Redirection Endoluminal Device (FRED; MicroVention Terumo, Tustin, California). For this report, we reviewed the published literature for properties of the currently available FRED devices regarding safety, efficacy, and potential risks and complications associated with their use.

EXPERT OPINION

FRED and FRED Jr are the new flow diverter devices for which the existing data suggest that they are safe and efficient in addressing the treatment issues with giant, wide-necked saccular and fusiform aneurysms and those with perforators and branch vessels at high risk of occlusion with surgical clipping. Evidence is mounting on their long-term durability which increases the confidence of both the endovascular surgeon in prescribing and the patient side in accepting these FDs as treatment option for intracranial aneurysms.

Long-term clinical and angiographic follow-up results of the dual-layer flow diverter device (FRED) for the treatment of intracranial aneurysms in a multicenter study

PURPOSE

Our aim was to determine the long-term safety and efficacy of the Flow Re-Direction Endoluminal Device (FRED) in this multicenter study with prospective design.

MATERIALS-METHOD

This study included 136 consecutive patients with 155 aneurysms treated between March 2013 and June 2016 in 10 centers. Twenty-two (16.2%) patients presented with rupture of the index aneurysm. Large/giant aneurysms comprised 1/3 of the cohort. Adjuvant coil use during the treatment was 15.5%. The effectiveness measure in the study was the percentage of aneurysms with stable occlusion at follow-up.

RESULTS

Vascular imaging follow-up was performed at least once in 131/136 (96.3%) patients with 148/155 (95.5%) aneurysms up to 75 months (mean: 37.3 months; median: 36 months according to latest follow-up), and 102/155(65.8%) aneurysms in 90/136 (66.2%) patients had ≥ 24-month control. According to the latest controls, the overall stable occlusion rate was 91.9% (95% CI, 87.5 to 96.3%). Three out of 148 aneurysms with follow-up were retreated (2%, 95% CI 0.0 to 4.3%). Adverse events were noted in 19/136 (14%, 95% CI, 9 to 21%) patients with a morbidity of 1.5% (95% CI, 0.0 to 3.5%). Mortality was 1/136 (0.7%, 95% CI, 0.02 to 2.2%) and was unrelated to aneurysm treatment. In-stent stenosis (ISS) was detected in 10/131 of the patients with follow-up (7.6%, 95% CI; 3.1 to 12.2%), only one being symptomatic. No adverse events have occurred in any of the patients with follow-up after 24 months, except the one resulting from ISS.

CONCLUSION

In the treatment of cerebral aneurysms which were candidates for flow diversion technique, this study showed long-term efficacy of FRED with good safety and occlusion rates.

A single-centre experience and literature review of Flow Re-Directional Endoluminal Device (FRED) in endovascular treatment of intracranial aneurysms

AIM

To present initial single-centre experience with the Flow Re-Direction Endoluminal Device, FRED.

MATERIALS AND METHODS

This was a retrospective study. All patients treated with FRED from October 2015 to April 2017 were included in the study. Details of the aneurysms, complications as well as follow-up results were recorded. A PubMed search was performed using the keywords "Flow Re-Direction Endoluminal Device", "FRED", "flow diverter", "FD", "FD Stent", "flow re-direction" and "flow redirection" and the results were reviewed and compared to the present authors.

RESULTS

A total of 21 patients with 25 aneurysms were analysed. No patient was lost to follow-up. At 6 months follow-up, 17 aneurysms (68%) were completely occluded, five had reduced flow, two had persistent flow and the remaining one showed increased flow. Two aneurysms from the reduced flow at 6 months had achieved complete occlusion at 1 year, raising the complete occlusion rate to 76%. Overall, 22/25 (88%) aneurysms were either occluded completely or had reduced flow at 1 year. The appearances of the other aneurysms were stable in subsequent follow-ups. Three complications were recorded (one haemorrhagic, two occlusive/thromboembolic). There was no mortality in the present study. The occlusion rate at University Hospital of Wales as well as the complication rate was comparable to other centres on published data.

CONCLUSION

FRED is a safe and effective flow diverter, which can be used to treat complex aneurysms that would have been of higher risk and for which for conventional coiling would be ineffective or unsuitable.

Overview of Different Flow Diverters and Flow Dynamics

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

Treatment of Ruptured Blister-Like Aneurysms with the FRED Flow Diverter: A Multicenter Experience

BACKGROUND AND PURPOSE

Treatment of ruptured blister-like aneurysms is technically challenging. This study aimed at analyzing the safety and efficacy of the Flow-Redirection Endoluminal Device (FRED) in the treatment of ruptured blister-like aneurysms.

MATERIALS AND METHODS

In a retrospective multicenter study, all patients treated with the FRED due to a ruptured intracranial blister-like aneurysm between January 2013 and May 2019 were analyzed. The primary end points for clinical safety were mRS 0-2 at 6 months after treatment and the absence of major ipsilateral stroke or death. The primary end points for efficacy were the absence of rebleeding after treatment and complete angiographic occlusion according to the O'Kelly-Marotta classification at 6 months after treatment.

RESULTS

In total, 30 patients with 30 ruptured blister-like aneurysms were treated. Immediate complete aneurysm obliteration (O'Kelly-Marotta classification D) with the FRED was achieved in 10 patients (33%). Of the 26 patients with follow-up, complete obliteration was achieved in 21 patients (80%) after 6 months and in 24 patients (92%) in the final follow-up (median, 22 months). Twenty-three patients (77%) achieved mRS 0-2 at 6 months. Major stroke or death occurred in 17%. Two patients died due to pneumonia, and 2 patients died due to infarction following cerebral vasospasm. There was no case of rebleeding after FRED implantation. There was 1 case of delayed asymptomatic stent occlusion.

CONCLUSIONS

Treatment of ruptured blister-like aneurysms with the FRED is safe and effective.

Review of current intracranial aneurysm flow diversion technology and clinical use

Endovascular treatment of intracranial aneurysms (IAs) has evolved considerably over the past decades. The technological advances have been driven by the experience that coils fail to completely exclude all IAs from the blood circulation, the need to treat the diseased parent vessel segment leading to the aneurysm formation, and expansion of endovascular therapy to treat more complex IAs. Stents were initially developed to support the placement of coils inside wide neck aneurysms. However, early work on stent-like tubular braided structure led to a more sophisticated construct that then later was coined as a flow diverter (FD) and found its way into clinical application. Although FDs were initially used to treat wide-neck large and giant internal carotid artery aneurysms only amenable to surgical trap with or without a bypass or endovascular vessel sacrifice, its use in other types of IAs and cerebrovascular pathology promptly followed. Lately, we have witnessed an explosion in the application of FDs and subsequently their modifications leading to their ubiquitous use in endovascular therapy. In this review we aim to compile the available FD technology, evaluate the devices' peculiarities from the authors' perspective, and analyze the current literature to support initial and expanded indications, recognizing that this may be outdated soon.

Derivo embolization device in the treatment of unruptured intracranial aneurysms: a prospective multicenter study

Background

Flow diverters (FD) are used regularly for the endovascular treatment of unruptured intracranial aneurysms. We aimed to assess the safety and effectiveness of the Derivo embolization device (DED) with respect to long-term clinical and angiographic outcomes.

Methods

A prospective multicenter trial was conducted at 12 centers. Patients presenting with modified Rankin Score (mRS) of 0–1, treated for unruptured intracranial aneurysms with DED were eligible. Primary endpoint was the mRS assessed at 18 months with major morbidity defined as mRS 3–5. Satisfactory angiographic occlusion was defined as 3+4 on the Kamran scale.

Results

Between July 2014 and February 2018, 119 patients were enrolled. Twenty-three patients were excluded. Ninety-six patients, 71 (74%) female, mean age 54±12.0 years, were included in the analysis. Mean aneurysm size was 14.2±16.9 mm. The mean number of devices implanted per patient was 1.2 (range 1–3). Clinical follow-up at 18 months was available in 90 (94%) patients, resulting in a mean follow-up period of 14.8±5.2 months. At last available follow-up of 96 enrolled patients, 91 (95%) remained mRS 0–1. The major morbidity rate (mRS 3–5) was 3.1% (3/96), major stroke rate was 4.2% (4/96), and mortality was 0%. Follow-up angiographies were available in 89 (93%) patients at a median of 12.4±5.84 months with a core laboratory adjudicated satisfactory aneurysm occlusion in 89% (79/89).

Conclusion

Our results suggest that DED is a safe and effective treatment for unruptured aneurysms with high rates of satisfactory occlusion and comparably low rates of permanent neurological morbidity and mortality.

Trial registration

DRKS00006103

Economics of the Management of Craniospinal Chordoma and Chondrosarcoma and the feasibility of the bundled payment model

BACKGROUND

The Centers for Medicare and Medicaid Services (CMS) created a new reimbursement model "Bundled Payment for Care Improvement (BPCI)" which reimburses providers a predetermined payment in advance to cover all possible services rendered within a certain time window. Chordoma and Chondrosarcoma are locally aggressive malignant primary bony tumors. Treatment includes surgical resection and radiotherapy with substantial risk for recurrence which necessitates monitoring and further treatment. We assessed the feasibility of the BPCI model in these neurosurgical diseases.

METHODS

We selected patients with chordoma/chondrosarcoma from inpatient admission table using the International Classification of Disease, 9th (ICD-9), and 10th (ICD-10) revision codes. We collected the patients' demographics and insurance type at the index hospitalization. We recorded the following outcomes length of stay, total payment, discharge disposition, and complications for the index hospitalization. For post-discharge, we collected the 30 days and 3/6/12 months inpatient admission, outpatient service, and medication refills. Continuous variables were summarized by means with standard deviations, median with interquartile and full ranges (minimum-maximum); Continuous outcomes were compared by nonparametric Wilcoxson rank-sum test. All tests were 2-sided with a significance level of 0.05. Statistical data analysis was performed in SAS 9.4 (SAS Institute, Inc, Cary, NC).

RESULTS

The population size was 2041 patients which included 1412 patients with cranial (group1), 343 patients with a mobile spine (group 2), and 286 patients with sacrococcygeal (group 3) chordoma and chondrosarcoma. For index hospitalization, the median length of stay (days) was 4, 6, and 7 for groups 1, 2, and 3 respectively (P<.001). The mean payments were ($58,130), ($84,854), and ($82,440), for groups 1, 2, and 3 respectively (P=.02). The complication rates were 30%, 35%, and 43% for groups 1, 2, and 3 respectively (P<.001). Twelve months post-discharge, the hospital readmission rates were 44%, 53%, and 65% for groups 1, 2, and 3, respectively (P<.001). The median payments for this period were ($72,294), ($76,827), and ($101,474), for groups 1, 2, and 3, respectively (P <.001).

CONCLUSION

The management of craniospinal chordoma and chondrosarcoma is costly and may extend over a prolonged period. The success of BPCI requires a joint effort between insurers and hospitals. Also, it should consider patients' comorbidities, the complexity of the disease. Finally, the adoptionof quality improvement programs by hospitals can help with cost reduction.

Comparison of PED and FRED flow diverters for posterior circulation aneurysms: a propensity score matched cohort study

BACKGROUND

Flow diversion is a common endovascular treatment for cerebral aneurysms, but studies comparing different types of flow diverters are scarce.

OBJECTIVE

To perform a propensity score matched cohort study comparing the Pipeline Embolization Device (PED) and Flow Redirection Intraluminal Device (FRED) for posterior circulation aneurysms.

METHODS

Consecutive aneurysms of the posterior circulation treated at 25 neurovascular centers with either PED or FRED were collected. Propensity score matching was used to control for age, duration of follow-up imaging, adjunctive coiling, and aneurysm location, size, and morphology; previously ruptured aneurysms were excluded. The two devices were compared for the following outcomes: procedural complications, aneurysm occlusion, and functional outcome.

RESULTS

A total of 375 aneurysms of the posterior circulation were treated in 369 patients. The PED was used in 285 (77.2%) and FRED in 84 (22.8%) procedures. Aneurysms treated with the PED were more commonly fusiform and larger than those treated with FRED. To account for these important differences, propensity score matching was performed resulting in 33 PED and FRED unruptured aneurysm pairs. No differences were found in occlusion status and neurologic thromboembolic or hemorrhagic complications between the two devices. The proportion of patients with favorable functional outcome was higher with FRED (100% vs 87.9%, p=0.04).

CONCLUSION

Comparative analysis of PED and FRED for the treatment of unruptured posterior circulation aneurysms did not identify significant differences in aneurysm occlusion or neurologic complications. Variations in functional outcomes warrant additional investigations.

FRED Italian Registry: a multicenter experience with the flow re-direction endoluminal device for intracranial aneurysms

OBJECTIVE

The introduction of flow-diverter devices (FDDs) has revolutionized the endovascular treatment of intracranial aneurysms. Here the authors present their Italian multicenter experience using the flow re-direction endoluminal device (FRED) in the treatment of cerebral aneurysms, evaluating both short- and long-term safety and efficacy of this device.

METHODS

Between February 2013 and December 2014, 169 consecutive aneurysms treated using FRED in 166 patients were entered into this study across 30 Italian centers. Data collected included patient demographics, aneurysm location and characteristics, baseline angiography, adverse event and serious adverse event information, morbidity and mortality rates, and pre- and posttreatment modified Rankin Scale scores, as well as angiographic and cross-sectional CT/MRI follow-up at 3-6 months and/or 12-24 months per institutional standard of care. All images were reviewed and adjudicated by an independent core lab.

RESULTS

Of the 169 lesions initially entered into the study, 4 were later determined to be extracranial or nonaneurysmal by the core lab and were excluded, leaving 165 aneurysms in 162 patients treated in 163 procedures. Ninety-one (56.2%) patients were asymptomatic with aneurysms found incidentally. Of the 165 aneurysms, 150 (90.9%) were unruptured. One hundred thirty-four (81.2%) were saccular, 27 (16.4%) were fusiform/dissecting, and the remaining 4 (2.4%) were blister-like. One hundred thirty-seven (83.0%) arose from the anterior circulation.FRED deployment was impossible in 2/163 (1.2%) cases, and in an additional 4 cases (2.5%) the device was misdeployed. Overall mortality and morbidity rates were 4.3% and 7.3%, respectively, with rates of mortality and morbidity potentially related to FRED of up to 2.4% and 6.2%, respectively. Neuroimaging follow-up at 3-6 months showed complete or nearly complete occlusion of the aneurysm in 94% of cases, increasing to 96% at 12-24 months' follow-up. Aneurysmal sac shrinkage was observed in 78% of assessable aneurysms.

CONCLUSIONS

This preliminary experience using FRED for endovascular treatment of complex unruptured and ruptured aneurysms showed a high safety and efficacy profile that is comparable to those of other FDDs currently in use.

Stent-Assisted Coiling Using Leo+ Baby Stent : Immediate and Mid-Term Results

Background

Stent-assisted coiling is well-established for treatment of cerebral aneurysms. The technique enables treatment of wide-neck, bifurcation and recurrent aneurysms with high packing rates. While described in extenso for laser cut stents, the results of patients treated with the Leo+ Baby (Balt, Montmorency, France) braided microstent are presented.

Material and Methods

Patients were included if treated with a Leo+ Baby and with digital subtraction angiography (DSA) follow-up available of at least 6 months. Data were evaluated for successful deployment, aneurysm occlusion according to the modified Raymond-Roy classification (MRRC), stent patency and procedure-related morbidity and mortality.

Results

A total of 81 patients were included and Leo+ Baby deployment was successful in all cases. Coils were used in 80 cases. In 1 case 2 stents were used stent-in-stent without additional coiling. Initial aneurysm occlusion rates were MRRC_i1 51.9%, MRRC_i2 11.1%, MRRC_i3a 24.7% and MRRC_i3b 12.3%. Occlusion rates after 6 months were MRRC_6m1 78.9%, MRRC_6m2 3.9%, MRRC_6m3a 6.6% and MRRC_6m3b 10.5%. Procedure-related morbidity was 1 case of acute stent thrombosis successfully treated with tirofiban and 1 case with transient hemiparesis due to stent thrombosis after 4 months. There was 1 case of coil-associated subarachnoid hemorrhage (SAH) which caused prolonged hospitalization. No procedure-related mortality was observed.

Conclusion

The results confirm that stent-assisted coiling with the Leo+ Baby stent is safe and efficient for treatment of wide neck or recurrent cerebral aneurysms. Spontaneous progressive aneurysm occlusion over 6 months supports the theory of considerable flow-modulating effects of Leo+ Baby.