Comparison of Pipeline Embolization Device and Flow Re-Direction Endoluminal Device Flow Diverters for Internal Carotid Artery Aneurysms: A Propensity Score-Matched Cohort Study

Pipeline Embolization Device and Flow Re-Direction Endoluminal Device for Intracranial Aneurysms: A Comparative Systematic Review and Meta-Analysis Study

BACKGROUND

When it comes to intracranial aneurysms, the quest for more effective treatments is ongoing. Flow diversion represents a growing advancement in this field. This review seeks to compare 2 variants of the endovascular flow diversion method: the Flow Re-Direction Endoluminal Device (FRED) and the Pipeline Embolization Device (PED).

METHODS

A systematic review was conducted according to the PRISMA guideline using PubMed, Scopus, Web of Science, and Embase, using appropriate terms to compare PED and FRED in double-arm studies from conception until October 8th, 2023.

RESULTS

The meta-analysis encompassed 1769 patients, with a predominance of females (75.5%), among whom 973 patients underwent FRED procedures, while 651 received PED interventions. At 6 months, complete occlusion rates were 0.62 for FRED and 0.68 for PED (P = 0.68). At 1 year and the last follow-up, no significant differences were observed between FRED and PED, respectively. Adequate occlusion rates were similar between FRED and PED (0.82 vs. 0.79, P = 0.68). FRED showed a statistically significant higher rate of good mRS scores at follow-up (1.00 vs. 0.97, P = 0.03). Hemorrhage and re-treatment rates were higher in PED (P < 0.01) without considering the rupture status of the aneurysms due to the lack of data.

CONCLUSIONS

This meta-analysis suggests comparable efficacy but different safety profiles between FRED and PED in treating intracranial aneurysms. FRED demonstrated a higher rate of good modified Rankin scores, while PED showed increased hemorrhage and re-treatment rates. Understanding these differences is crucial for informed decision-making in clinical practice.

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.

Comparative Efficacy of Flow Diverter Devices in the Treatment of Carotid Sidewall Intracranial Aneurysms: a Retrospective, Multicenter Study

BACKGROUND

The comparative efficacy and safety of first-generation flow diverters (FDs), Pipeline Embolization Device (PED) (Medtronic, Irvine, California), Silk (Balt Extrusion, Montmorency, France), Flow Re-direction Endoluminal Device (FRED) (Microvention, Tustin, California), and Surpass Streamline (Stryker Neurovascular, Fremont, California), is not directly established and largely inferred.

PURPOSE

This study aimed to compare the efficacy of different FDs in treating sidewall ICA intracranial aneurysms.

METHODS

We conducted a retrospective review of prospectively maintained databases from eighteen academic institutions from 2009-2016, comprising 444 patients treated with one of four devices for sidewall ICA aneurysms. Data on demographics, aneurysm characteristics, treatment outcomes, and complications were analyzed. Angiographic and clinical outcomes were assessed using various imaging modalities and modified Rankin Scale (mRS). Propensity score weighting was employed to balance confounding variables. The data analysis used Kaplan-Meier curves, logistic regression, and Cox proportional-hazards regression.

RESULTS

While there were no significant differences in retreatment rates, functional outcomes (mRS 0-1), and thromboembolic complications between the four devices, the probability of achieving adequate occlusion at the last follow-up was highest in Surpass device (HR: 4.59; CI: 2.75-7.66, p < 0.001), followed by FRED (HR: 2.23; CI: 1.44-3.46, p < 0.001), PED (HR: 1.72; CI: 1.10-2.70, p = 0.018), and Silk (HR: 1.0 ref. standard). The only hemorrhagic complications were with Surpass (1%).

CONCLUSION

All the first-generation devices achieved good clinical outcomes and retreatment rates in treating ICA sidewall aneurysms. Prospective studies are needed to explore the nuanced differences between these devices in the long term.

Perioperative Antiplatelet Management in the Flow-Diverter Treatment for Unruptured Cerebral Aneurysms: A Single-Center, Retrospective Analysis

BACKGROUND

Although periprocedural antiplatelet therapy for the treatment of unruptured intracranial aneurysms (UIAs) using flow-diverter stents (FDSs) is necessary to avoid thromboembolic complications, a definite antiplatelet therapy has not been established. We aimed to evaluate the safety and efficacy of periprocedural antiplatelet management in UIA treatment with FDS.

METHODS

A single-center retrospective analysis of consecutive patients with UIAs treated with FDSs between September 2013 and January 2022 was conducted. Patients received dual antiplatelet therapy (DAPT) (aspirin and clopidogrel) for 14-day before and 3-6 months after FDS placement. Platelet aggregation was evaluated prior to treatment using light transmission aggregometry, which was classified into 3 grades; 1-3: promoted, 4-6: appropriate, and 7-9: non-responder, for adenosine diphosphate (ADP) and collagen. By this classification, the antiplatelet regimen was modified. Outcome included hemorrhagic and ischemic events.

RESULTS

193 patients with 200 UIAs underwent 213 FDSs placement. The median platelet aggregability grade before treatment was 5 for ADP and 4 for collagen. Antiplatelet therapy modification was performed in 62 patients (32.1%). The median postoperative DAPT duration was 94 days. Antiplatelet medicine-related hemorrhagic events occurred in 4 patients (2.1%) and ischemic events occurred in 6 patients (3.1%). These patients had no morbido-mortality.

CONCLUSIONS

Periprocedural antiplatelet management based on the value of platelet aggregability was relatively safe and effective for treating UIA with FDS.

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.

Pipeline versus Tubridge in the treatment of unruptured posterior circulation aneurysms

BACKGROUND

To compare the safety and efficacy of pipeline embolization device (PED) and Tubridge flow diverter (TFD) for unruptured posterior circulation aneurysms.

METHODS

Posterior aneurysm patients treated with PED or TFD between January, 2019, and December, 2021, were retrospectively reviewed. Patients' demographics, aneurysm characteristics, treatment details, complications, and follow-up information were collected. The procedural-related complications and angiographic and clinical outcome were compared.

RESULTS

A total of 107 patients were involved; PED was applied for 55 patients and TFD for 52 patients. A total of 9 (8.4%) procedural-related complications occurred, including 4 (7.3%) in PED group and 5 (9.6%) in TFD group. During a mean of 10.3-month angiographic follow-up for 81 patients, complete occlusion was achieved in 35 (85.4%) patients in PED group and 30 (75.0%) in TFD group. The occlusion rate of PED group is slightly higher than that of TFD group. A mean of 25.0-month clinical follow-up for 107 patients showed that favorable clinical outcome was achieved in 53 (96.4%) patients in PED group and 50 (96.2%) patients in TFD group, respectively. No statistical difference was found in terms of procedural-related complications (p = 0.737), occlusion rate (p = 0.241), and favorable clinical outcome (0.954) between groups.

CONCLUSIONS

The current study found no difference in complication, occlusion, and clinical outcome between PED and TFD for unruptured PCAs.

Difference in the cumulative incidence of aneurysmal occlusion by Flow Re-direction Endoluminal Device and Pipeline Embolization Device in the treatment of unruptured internal carotid artery aneurysms: a propensity score-matched cohort study

The introduction of flow diverters (FDs) has represented a paradigm shift in the management of unruptured cerebral aneurysms (UCA). Flow Re-direction Endoluminal Devices (FREDs) and Pipeline Embolization Devices (PEDs) have gained widespread popularity. We aimed to investigate the cumulative incidence of aneurysm occlusion. A total of 195 patients with 199 UCAs were analyzed retrospectively. The outcomes were aneurysmal occlusion during the follow-up, a modified Rankin Scale score of 0-2 at 90 days, additional treatment, major stroke, and steno-occlusive events of FD. Propensity score-matched analysis was performed, controlling for age, sex, aneurysmal size, and location of the internal carotid artery (ICA) aneurysm. Non-ICA aneurysms were excluded from matching. During the follow-up period (median, 366 days), complete and satisfactory aneurysmal occlusions were observed in 128 (68%) and 148 (78%) of 189 UCAs in the unmatched cohort. The 142 (71 each) propensity score-matched cohort was complied. The FRED group had a higher cumulative incidence of ICA aneurysm occlusion (complete: HR 2.7, 95% CI 1.4-5.1, p = 0.0025; satisfactory: HR 2.4, 95% CI 1.1-5.2, p = 0.025). The proportion of additional treatment was significantly smaller in the FRED group (OR 0.077, 95% CI 0.010-0.57, p = 0.0007). Other outcomes showed no significant differences. Propensity score-matched analysis indicated that FRED might have a higher cumulative incidence of aneurysmal occlusion in the treatment of unruptured ICA aneurysms. Whether a cumulative incidence of aneurysmal occlusion may differ by the type of FDs warrants further investigation.

Effect of Stent Porosity, Platelet Function Test Usage, and Dual Antiplatelet Therapy Duration on Clinical and Radiographic Outcomes After Stenting for Cerebral Aneurysms: A Meta-Analysis

BACKGROUND

The use of stents with various porosities for treating cerebral aneurysms requires dual antiplatelet therapy (DAPT) without clear guidelines on the utility of platelet function tests (PFTs) and the duration of DAPT. We sought to determine the effects of stent porosity, PFT usage, and DAPT duration on the radiographic and clinical outcomes after stenting of cerebral aneurysms.

METHODS

PubMed was searched on March 29, 2021 for studies of cerebral aneurysm stenting that had specified the stent type and DAPT duration. A random effects meta-analysis was used to measure the prevalence of nonprocedural thrombotic and hemorrhagic events, clinical outcomes, aneurysm occlusion, and in-stent stenosis stratified by stent porosity, PFT usage, and DAPT duration.

RESULTS

The review yielded 105 studies (89 retrospective and 16 prospective) with 117 stenting cohorts (50 high porosity, 17 intermediate porosity, and 50 low porosity). In the high-, intermediate-, and low-porosity stenting cohorts, PFT usage was 26.0%, 47.1%, and 62.0% and the mean DAPT duration was 3.51 ± 2.33, 3.97 ± 1.92, and 5.18 ± 2.27 months, respectively. The intermediate-porosity stents showed a reduced incidence of hemorrhagic events (π = 0.32%) compared with low-porosity stents (π = 1.36%; P = 0.01) and improved aneurysm occlusion (π = 6.18%) compared with high-porosity stents (π = 14.42%; P = 0.001) and low-porosity stents (π = 11.71%; P = 0.04). The prevalence of in-stent stenosis was lower for the intermediate-porosity (π = 0.57%) and high-porosity (π = 1.51%) stents than for the low-porosity stents (π = 3.30%; P < 0.05). PFT use had resulted in fewer poor clinical outcomes (π = 3.54%) compared with those without PFT use (π = 5.94%; P = 0.04). The DAPT duration had no effect on the outcomes.

CONCLUSIONS

In the present meta-analysis, which had selected for studies of cerebral aneurysm stenting that had reported the DAPT duration, intermediate-porosity stents and PFT use had resulted significantly improved outcomes. No effect of DAPT duration could be detected.

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.

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.

Distal migration of the flow-redirection endoluminal device immediately after treatment: A case report and literature review

Background:

A flow diverter (FD) has been a promising endovascular therapeutic modality for challenging intracranial aneurysms. However, stent migration has been an unusual complication. Until recently, among some types of FDs, the migration of the flow-redirection endoluminal device (FRED; MicroVention Inc., Aliso Viejo, CA, USA) has almost never been reported. Herein, we report a case of acute distal migration of a single FRED secondary to in-stent thrombi with symptomatic ischemic stroke and review the literature on the distal migration of FDs.

Case Description:

A 35-year-old woman was diagnosed with a left unruptured internal carotid-ophthalmic artery aneurysm. A 3.5 mm diameter and 17 mm long FRED was adequately deployed. The patient awoke from general anesthesia without neurological deficits. However, shortly after the procedure, the patient presented with conjugate deviation toward the left side, right severe hemiparesis, and total aphasia. Although the symptoms gradually improved, angiography was performed. Angiography revealed some in-stent thrombi and distal migration of the FRED, and initially, one of the left M2 inferior trunk branches was occluded by an embolic thrombus. However, the thrombus spontaneously migrated distally without any specific treatment. Finally, despite leaving the migrated stent in situ, the flow almost completely improved, and the patient’s neurologic deficits disappeared. Magnetic resonance imaging following treatment revealed only a small cerebral infarction in the left temporo-occipital area.

Conclusion:

Distal migration of an FD in an acute setting, including the FRED, may occur even following appropriate placement. In-stent thrombosis can cause distal stent migration and thromboembolic stroke.

Microsurgical Clipping of Intracranial Aneurysms in the Endovascular Era

The treatment of intracranial aneurysms (IA) began in the late 19th century. Some degree of controversy has always surrounded the best treatment modality for IA. Cushing and Dandy debated about cervical carotid ligation as the only surgical alternative before the introduction of microsurgical clipping. In the early 21st century, the debate has centered on surgical versus^ endovascular techniques. With the advent of newer endovascular techniques and devices, there has been a dramatic shift in treatment paradigms toward endovascular intervention that is preferred by both physicians and patients. However, there will always be a need for microsurgical cerebrovascular expertise since some aneurysms cannot or should not be embolized. This creates a difficult conundrum as only the most complex of aneurysms will require open surgery, but the lack of volume and training will be a challenge in teaching and maintaining the surgical expertise required to safely treat them. The purpose of this review is to discuss the history of IA treatment and critically evaluate the current state of the art of IA treatment, with a specific focus on the necessary role microsurgical clipping continues to play in the current treatment landscape.

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.

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.

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.

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.

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.

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.

Promoting endothelialization of flow-diverting stents: a review

Intracranial flow-diverting (FD) stents have revolutionized the treatment of intracranial aneurysms in recent years, but complications resulting from failed endothelialization can still occur. Approaches to promote endothelialization are understudied, but hold promise in mitigating both short- and long-term complications associated with FD stent insertion. The aim of this review is to highlight the various features of and modifications that have been made to FD stents in order to expedite endothelialization. More specifically, we focus on how endothelialization can be influenced by the stent design, wall apposition, surface modifications, and the inclusion of biological agents.

Flow diversion for internal carotid artery aneurysms: Impact of complex aneurysm features and overview of outcome

OBJECTIVE

Flow diversion is a popular technique used to treat ordinary small, as well as complex internal carotid artery (ICA) aneurysms. We describe aneurysm occlusion rates, complications and patient outcomes in patients with ICA aneurysms treated with flow diverter stents.

PATIENTS AND METHODS

We identified all consecutive patients with ICA aneurysms that were treated with flow diverter stents between 2014 and 2019 at our institution. We divided the aneurysms into two anatomic subgroups (cavernous and supraclinoid segments). All the imaging studies and medical records were reviewed for relevant features in relation to aneurysms, complications and patient outcomes.

RESULTS

A total of 62 patients with 76 ICA aneurysms (72 unruptured; 4 ruptured) were treated with 70 flow diversion procedures, including six re-treatments. Complete aneurysm occlusion was achieved in 61 % of patients at 6-month follow-up (cavernous 69 %, supraclinoid 58 %), and in 69 % at the latest follow-up (mean of 18 months). Postprocedural intracranial ischemia or hemorrhage was seen in 24 % of patients, including two aneurysm ruptures after flow diversion, and related major long-term functional decline or mortality was seen in 6% of patients. Preprocedural dysfunction of extraocular muscles or vision disturbance improved moderately at best (40-60 %). At the latest follow-up, 54 patients (87 %) were functionally independent (mRS ≤2).

CONCLUSION

Flow diversion for cavernous and supraclinoid ICA aneurysms demonstrated acceptable results, but complex aneurysm features cause uncertainty in predicting aneurysm occlusion probability. Patients should be informed of the non-negligible rate of complications, and of only moderate improvement rate of cranial nerve dysfunctions.

The FRED for Cerebral Aneurysms of the Posterior Circulation: A Subgroup Analysis of the EuFRED Registry

BACKGROUND AND PURPOSE

Flow diversion for the posterior circulation remains a promising treatment option for selected posterior circulation aneurysms. The Flow-Redirection Intraluminal Device (FRED) system has not been previously assessed in a large cohort of patients with posterior circulation aneurysms. The purpose of the present study was to assess safety and efficacy of FRED in this location.

MATERIALS AND METHODS

Consecutive patients with posterior circulation aneurysms treated at 8 centers participating in the European FRED study (EuFRED) between April 2012 and January 2019 were retrospectively reviewed. Complication and radiographic and functional outcomes were evaluated.

RESULTS

Eighty-four patients (median age, 54 years) with 84 posterior circulation aneurysms were treated with the FRED. A total of 25 aneurysms (29.8%) had previously ruptured, even though most aneurysms were diagnosed incidentally (45.2%). The intradural vertebral artery was the most common location (50%), and saccular, the most common morphology (40.5%). The median size was 7 mm. There were 8 (9.5%) symptomatic thromboembolic and no hemorrhagic complications. Thromboembolic complications occurred mostly (90.9%) in nonsaccular aneurysms. On last follow-up at a median of 24 months, 78.2% of aneurysms were completely occluded. Functional outcome at a median of 27 months was favorable in 94% of patients. All mortalities occurred in patients with acute subarachnoid hemorrhage and its sequelae.

CONCLUSIONS

The largest cohort of posterior circulation aneurysms treated with the FRED to date demonstrated favorable safety and efficacy profiles of the device for this indication. Treatment in the setting of acute subarachnoid hemorrhage was strongly related to mortality, regardless of whether procedural complications occurred.