Treatment of Intracranial Aneurysms With the SILK Embolization Device in a Multicenter Study. A Retrospective Data Analysis

No Delayed Ruptures on Long-Term Follow-Up of a Case Series of Persistently Filling Saccular Internal Carotid Artery Aneurysms After Flow Diversion With the Pipeline Embolization Device

BACKGROUND AND OBJECTIVES

Flow diversion of intracranial aneurysms results in high occlusion rates. However, 10% to 20% remain persistently filling at 1 year. Often, these are retreated, but benefits of retreatment are not well established. A better understanding of the long-term rupture risk of persistently filling aneurysms after flow diversion is needed.

METHODS

Our institutional database of 974 flow diversion cases was queried for persistently filling saccular aneurysms of the clinoidal, ophthalmic, and communicating segments of the internal carotid artery treated with the pipeline embolization device (PED, Medtronic). Persistent filling was defined as continued flow into the aneurysm on 1 year catheter angiogram. The clinical record was queried for retreatments and delayed ruptures. Clinical follow-up was required for at least 2 years.

RESULTS

Ninety-four persistent aneurysms were identified. The average untreated aneurysm size was 5.6 mm. A branch vessel originated separately in 55% of cases from the body of the aneurysm in 10.6% of cases and from the neck in 34% of cases. Eighteen percent of aneurysms demonstrated >95% filling at 1 year, and 61% were filling 5% to 95% of their original size. The mean follow-up time was 4.9 years, including 41 cases with >5 years. No retreatment was undertaken in 91.5% of aneurysms. There were no cases of delayed subarachnoid hemorrhage.

CONCLUSION

Among saccular internal carotid artery aneurysms treated with PED that demonstrated persistent aneurysm filling at 1 year, there were no instances of delayed rupture on long-term follow-up. These data suggest that observation may be appropriate for continued aneurysm filling at least in the first several years after PED placement.

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.

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.

A Single Flow Re-direction Endoluminal Device for the Treatment of Large and Giant Anterior Circulation Intracranial Aneurysms

PURPOSE

The purpose of this study was to report the author's experiences in treating large (10-25 mm) and giant (>25 mm) intracranial aneurysms (IAs) using a single Flow Re-direction Endoluminal Device (FRED) without assistant coiling, with a focus on procedure-related complications.

MATERIALS AND METHODS

A total of 33 patients who were treated with FRED between January 2018 and July 2020 were retrospectively reviewed. The timing of procedure-related complications was chronologically categorized as acute (within 7 days), subacute (8 to 21 days), and delayed (after 21 days) periods. Follow-up angiography was performed at 2 to 27 months (mean 9.7 months), and clinical follow-up was performed at 1 to 31 months (mean 14.1 months) in all patients.

RESULTS

Six (18.2%) patients experienced procedure-related complications, including 2 (6.1%) in acute period, 1 (3.0%) in subacute period, and 3 (9.1%) in delayed period. Thromboembolic complications occurred in 5 (15.2%) patients and hemorrhagic complications in 1 (3.0%). Permanent morbidity and mortality rates were 3.0% each. Non-internal carotid artery (ICA) location of IAs (odds ratio 6.532; 95% confidence interval, 1.335-17.816; p=0.034) was the only independent risk factor for procedure-related complications on multivariate logistic regression analysis.

CONCLUSION

The procedure-related complication rate was 18.2% in this study. Procedure-related complications might increase when treating large and giant IAs located on a non-ICA, especially on the middle cerebral artery. Therefore, it may be suggested that neurointerventionists and endovascular neurosurgeons should pay attention to the location of IAs when treating large and giant IAs with a single FRED.

Superficial Temporal Artery (STA)-Posterior Cerebral Artery (PCA) Bypass through Zygomatic Anterior Temporal Approach for Complex PCA Aneurysm: Technique Notes

BACKGROUND

Posterior cerebral artery (PCA) aneurysms are rare and the majority are giant, dissecting, or fusiform in morphology. Proximal occlusion of PCA without revascularization causes a high risk of ischemic complications. This study aimed to evaluate the safety and validity of using superficial temporal artery (STA)-posterior cerebral artery (PCA) Bypass through zygomatic anterior temporal approach in complex PCA aneurysms.

METHODS

Trapping or resecting of the aneurysms and reconstruction of the distal PCA through a zygomatic anterior temporal approach were performed in 6 patients from June 2017 to August 2020. Postoperative angiography was used to confirm the obliteration of the aneurysms and the patency of bypass artery. Neurologic function was assessed by the modified Rankin Scale.

RESULTS

Four male and 2 female patients with a mean age of 43.8 years (Range, 21-58 years) were assessed. Subarachnoid hemorrhage occurred in 5 patients, including 3 patients with Hunt-Hess grade IV, 2 patients with grade III, and 1 patient with grade I. All PCA aneurysms were treated with trapping or resecting of the aneurysms and revascularization of the distal PCA. Postoperatively, all aneurysms were eliminated and no new permanent neurological deficit was found. During the follow-up, Modified mRS of all patients were improved: There were 2 patients with mRS Score 0, 1 patient with mRS Score 1, 1 patient with mRS Score 3, and 2 patients with mRS Score 4. The long-term graft patency rate was 100%.

CONCLUSION

The STA-PCA bypass appears to be a safe and effective method for the treatment of complex PCA aneurysms requiring supplementing the blood flow in the area of the PCA. We established a surgical route, allowing the procedure to be done through the zygomatic anterior temporal approach. This approach provides adequate operative field exposure and reduces retraction of the temporal lobe.

Repeat Flow Diversion for Cerebral Aneurysms Failing Prior Flow Diversion: Safety and Feasibility From Multicenter Experience

BACKGROUND AND PURPOSE

Aneurysmal persistence after flow diversion (FD) occurs in 5% to 25% of aneurysms, which may necessitate retreatment. There are limited data on safety/efficacy of repeat FD-a frequently utilized strategy in such cases.

METHODS

A series of consecutive patients undergoing FD retreatment from 15 centers were reviewed (2011-2019), with inclusion criteria of repeat FD for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months post-retreatment imaging. The primary outcome was aneurysmal occlusion, and secondary outcome was safety. A multivariable logistic regression model was constructed to identify predictors of incomplete occlusion (90%-99% and <90% occlusion) versus complete occlusion (100%) after retreatment.

RESULTS

Ninety-five patients (median age, 57 years; 81% women) harboring 95 aneurysms underwent 198 treatment procedures. Majority of aneurysms were unruptured (87.4%), saccular (74.7%), and located in the internal carotid artery (79%; median size, 9 mm). Median elapsed time between the first and second treatment was 12.2 months. Last available follow-up was at median 12.8 months after retreatment, and median 30.6 months after the initial treatment, showing complete occlusion in 46.2% and near-complete occlusion (90%-99%) in 20.4% of aneurysms. There was no difference in ischemic complications following initial treatment and retreatment (4.2% versus 4.2%; P>0.99). On multivariable regression, fusiform morphology had higher nonocclusion odds after retreatment (odds ratio [OR], 7.2 [95% CI, 1.97-20.8]). Family history of aneurysms was associated with lower odds of nonocclusion (OR, 0.18 [95% CI, 0.04-0.78]). Likewise, positive smoking history was associated with lower odds of nonocclusion (OR, 0.29 [95% CI, 0.1-0.86]). History of hypertension trended toward incomplete occlusion (OR, 3.10 [95% CI, 0.98-6.3]), similar to incorporated branch into aneurysms (OR, 2.78 [95% CI, 0.98-6.8]).

CONCLUSIONS

Repeat FD for persistent aneurysms carries a reasonable success/safety profile. Satisfactory occlusion (100% and 90%-99% occlusion) was encountered in two-thirds of patients, with similar complications between the initial and subsequent retreatments. Fusiform morphology was the strongest predictor of retreatment failure.

Silk® Flow Diverter Device for Intracranial Aneurysm Treatment: A Systematic Review and Meta-Analysis

Flow diverters have become a critical instrument for complex aneurysms treatment. However, limited data are currently available regarding short and long-term outcomes for the Silk flow diverter. The objective of the study is to determine neurological prognosis and mortality rates for the Silk flow diversion device used in intracranial aneurysms. A systematic review with meta-analysis was performed using databases. The following descriptors were used for the search: “SILK”, “Flow Diverter”, “Mortality”, and “Prognosis”. The following data were extracted: mortality, good functional outcome, Glasgow outcome scale, complete or near-complete occlusion rates, rate of retreatment, and complications (thromboembolic and hemorrhagic complications). A total of 14 studies were selected. Among the 14 studies, 13 were retrospective observational cohort studies and 1 was a prospective observational cohort study. The mortality rate was 2.84%. The clinical good outcomes rate was 93.3%. The poor outcome rate was 6.6%. The overall thromboembolic complication rate was 6.06% (95% confidence interval [CI] 0.00–6.37, P=0.12, I²=3.13%). The total hemorrhagic complication rate was 1.62% (95% CI 0.00–5.34, P=0.28, I²=1.56%). The complete aneurysm occlusion rate was 80.4% (95% CI 8.65–9.38, P<0.0001, I²=9.09%). The Silk diverter device has a good safety and efficacy profile for treating intracranial aneurysms with high complete occlusion rates.

Brazilian FRED Registry: A Prospective Multicenter Study for Brain Aneurysm Treatment-The BRED Study

BACKGROUND AND PURPOSE

The development of flow diverters has changed the endovascular approach to intracranial aneurysms. On the basis of good results, the indications for flow diverters have expanded to include aneurysms of different shapes, locations, and sizes. The objective of the study was to report on the performance of the Flow Re-Direction Endoluminal Device (FRED) in intracranial aneurysm treatment at early and medium-term follow-up.

MATERIALS AND METHODS

This single-arm, multicentric, prospective, observational study assessed aneurysm treatment with the FRED. The primary outcome was complete aneurysm occlusion at 6 and 12 months, and the secondary outcome was to evaluate the safety of the FRED with respect to stroke and death rates.

RESULTS

Between June 2016 and August 2018, a total of 100 consecutive patients with 131 aneurysms were treated in 107 procedures. Total occlusion rates were 91% and 95% at 6 and 12 months. There was 1 death, and the total final morbidity rate was 1.8%. The complication rate was 4.6%.

CONCLUSIONS

As reported previously, the FRED has proved to be a safe and effective tool, with high occlusion rates. The design of the stent makes it more difficult to perform balloon angioplasty compared with similar devices. A branch arising from the aneurysm sac was found to be a predictor of nonocclusion at 12 months, though larger series are needed to estimate the magnitude of the association.

Microsurgical clipping vs. arterial embolization in the treatment of ruptured anterior circulation aneurysms

OBJECTIVE

We aimed to compare the efficacy of microsurgical clipping of intracranial aneurysms with that of arterial embolization in the treatment of ruptured anterior circulation aneurysms.

METHODS

The clinical data of 68 patients treated in our hospital for ruptured anterior circulation aneurysms between January 2017 and March 2020 were analyzed retrospectively. According to the surgical methods, the patients were divided into two groups: the microsurgical clipping group (30 cases) and the arterial embolization group (38 cases). The following markers were compared between the two groups: Hunt-Hess classification (HHC) grading, aneurysm occlusion rate, and incidence of postoperative complications, length of hospital stay, hospitalization cost, and the scores of the Glasgow Outcome Scale, Modified Rankin Scale, and Barthel Index during the 6-months follow-up after hospital discharge.

RESULTS

The cases of HHC grade I and II increased in both groups at hospital discharge (both P<0.05), and there was no intergroup difference in this marker (P>0.05). The complete occlusion rate in the microsurgical clipping group was higher than that in the arterial embolization group (P<0.05). Compared with the microsurgical clipping group, the arterial embolization group had shorter length of hospital stay and higher hospitalization cost (both P<0.05). There was no difference in the total incidence of postoperative complications between the two groups (P>0.05). However, the arterial embolization group had lower incidence of intracranial infection and higher incidence of vasospasm than the microsurgical clipping group (both P<0.05). During the follow-up, the arterial embolization group had better results in terms of the Modified Rankin Scale and Barthel Index results and had more patients with GOS score of 5 points than the microsurgical clipping group (all P<0.05).

CONCLUSION

Both microsurgical clipping of intracranial aneurysms and arterial embolization can effectively treat ruptured anterior circulation aneurysms, and the short-term efficacy achieved by these two methods is similar. Compared with microsurgical clipping of intracranial aneurysms, arterial embolization can lead to shorter hospitalization, lower incidence of intracranial infection, and better patients' prognosis and quality of life after the operation. However, the microsurgical clipping of intracranial aneurysms can achieve higher complete occlusion rate, lower incidence of vasospasm, and lower hospitalization cost than arterial embolization.

Treatment of Intracranial Aneurysms Using the New Silk Vista Flow Diverter: Safety Outcomes at Short-Term Follow-Up

Background: Flow diverters are widely used as the first endovascular treatment option for complex brain aneurysms due to their high percentage of occlusion and low morbi-mortality. The Silk Vista device is a new generation of flow diverters designed to facilitate full visibility, improve apposition to the vessel wall, and enhance navigability. Indeed, its greatest advantage is that it enables the easier navigation of stents between 3.5 and 4.75 mm through a 0.021 microcatheter. The objective of this study was to evaluate the safety and effectiveness of Silk Vista systems for treating cerebral aneurysms.

Methods: This prospective observational study included 25 consecutive patients with 27 wide-necked unruptured aneurysms treated with SILK Vista who were retrospectively analyzed for safety and efficacy.

Results: Endovascular treatment was successfully performed in all patients. The final morbidity and mortality rates were both 0.0%. Short-term (3–5 months) angiographic follow-up revealed 21 complete occlusions and 6 near-complete occlusions. No significant parent artery stenosis was observed.

Conclusions: This report demonstrates the efficacy of Silk Vista in treating brain aneurysms, although longer experiences should be carried out to confirm our results.

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.

Propensity Score Analysis of Flow Diverters Placed in Scaffolding Stents

BACKGROUND AND PURPOSE

Flow-diverter deployment within a stent remains controversial, but flow-diverter deployment within a scaffolding stent has been performed occasionally. To date, an analysis of this scaffolding technique has not been reported. We aimed to evaluate whether the scaffolding technique adversely affects the outcomes of flow diversion.

MATERIALS AND METHODS

Patients who had undergone intracranial aneurysm treatment using a Silk flow diverter with (scaffolding group) or without (bare flow-diverter group) a scaffolding stent were identified retrospectively and compared. Propensity score matching was used to match the aneurysms in both groups for variables with a significant difference between groups. Aneurysm occlusion rates and clinical outcomes were compared.

RESULTS

There were 84 patients (105 aneurysms) in the bare flow-diverter group and 21 patients (22 aneurysms) in the scaffolding group (using 20 LEO stents and 1 Enterprise stent). The aneurysms in the scaffolding group were larger (mean, 13.1 [SD, 10.7] versus 7 [SD, 4.5] mm, P = .001) and more likely to be fusiform (40.9% versus 5.7%, P < .001) than in the bare flow-diverter group. After 2:1 propensity score matching, 24 aneurysms in the bare flow-diverter group and 15 in the scaffolding group were matched. Aneurysm occlusion rates did not significantly differ between groups at 1-3 months (41.2 versus 33.3%, P > .99), 3-6 months (55.5 versus 75.0%, P = .44), 7-12 months (65.0 versus 90.0%, P = .21), or beyond 1 year (73.6 versus 91.6%, P = .36). There was no difference in complication rates between the groups (P > .99).

CONCLUSIONS

Placement of a scaffolding stent before flow diversion does not adversely affect aneurysm occlusion or complication rates.

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.

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.

Safety and efficacy of the Silk flow diverter: Insight from the DIVERSION prospective cohort study

BACKGROUND AND PURPOSE

Flow diverters are considered as an essential tool in the stent-based treatment of complex intracranial aneurysms. We report here a subgroup analysis of the nationwide prospective DIVERSION study to investigate the safety and efficacy of the Silk flow diverter at 12 months follow-up.

METHODS

We performed a subgroup analysis of patients included in the DIVERSION, a national prospective cohort study including all flow diverters placement between 2012 and 2014 in France, and treated with the Silk. The primary outcome was the morbi-mortality at 12 months, including death, morbidity event and aneurysm retreatment within 12 months post-treatment. All reported serious events were adjudicated by an independent Data Safety and Monitoring Board. Satisfactory occlusion was defined as 3 or 4 on Kamran's scale by an independent imaging core laboratory during follow-up.

RESULTS

A total of 102 procedures involving 101 patients (mean age±standard deviation, 54.3±13.5 years) harbouring 118 aneurysms (113/118 located in the anterior circulation; mean size 8.2±7.1mm) were included. During the 12-month follow-up, 34 (33.3%) procedures experienced at least one morbi-mortality event: 3 deaths, 27 morbidity events and 4 retreatments. Overall, 1/3 deaths and 10/27 morbidity events were related to the device and/or the procedure, leading to a specific survival rate and a specific free-morbidity survival rate at 12 months of 98.98% [95% confidence interval, 92.98%-99.86%] and 89.73% [95%CI, 81.71%-94.36%], respectively. The rate of permanent-related neurological deficit was 5.9% within 12 months. One year follow-up imaging showed satisfactory occlusion in 82.2% of cases.

CONCLUSION

Flow diversion with the Silk device has a reasonable safety and effectiveness profile for the endovascular treatment of intracranial aneurysms.

Advances in endovascular aneurysm management: flow modulation techniques with braided mesh devices

Flow diverters and flow disruption technology, alongside nuanced endovascular techniques, have ushered in a new era of treating cerebral aneurysms. Here, we provide an overview of the latest flow modulation devices and highlight their clinical applications and outcomes.

Derivo Embolization Device for the Treatment of Intracranial Aneurysms

Background and Purpose—

Flow diverter technology improvements are necessary to provide safe and good results and enable the treatment of a larger variety of aneurysms. We report a nationwide experience with the Derivo Embolization Device in the treatment of intracranial aneurysms.

Methods—

BRAIDED (Brazilian Registry of Aneurysms Assigned to Intervention With the Derivo Embolization Device) is a multicenter, prospective, interventional, single-arm trial of the Derivo Embolization Device for the treatment of intracranial aneurysms. The primary effectiveness end point was total aneurysm occlusion at 6- and 12-month angiographies. The secondary safety end point was the absence of serious adverse events during follow-up. Univariable and multivariable logistic regression was performed to identify predictors of aneurysm persistence, periprocedural complications, and adverse events during follow-up.

Results—

Between December 2016 and October 2018, 146 patients harboring 183 intracranial aneurysms were treated in 151 interventions at 7 centers. Derivo Embolization Device placement was technically successful in all patients. Most aneurysms (86.9%) were located at the internal carotid artery, and the mean diameter was 6.7 mm. At 6 months, 113 of 140 (80.7%) aneurysms met the study’s primary end point, and 74 of 83 (89.2%) met the study’s primary end point at 12 months. Saccular morphology of the aneurysm (odds ratio, 5.66; 95% CI, 1.01–31.77) and the presence of a branch arising from the sac (odds ratio, 6.36; 95% CI, 2.11–22.36) predicted persistence. A long duration of follow-up (odds ratio, 0.86; 95% CI, 0.78–0.95) predicted total occlusion. Of the 146 enrolled patients, 138 (94.5%) were treated without serious adverse events during follow-up. In the multivariable analysis, aneurysms located at a sidewall were less likely to experience these events than those located at bifurcations (odds ratio, 0.07; 95% CI, 0.01–0.51).

Conclusions—

The Derivo Embolization Device is a safe and effective treatment for intracranial aneurysms.

Clinical Trial Registration—

URL: http://plataformabrasil.saude.gov.br/login.jsf . Unique identifier: CAAE 77089717.7.1001.5125.

Evaluation of flow changes after telescopic stenting of a giant fusiform aneurysm of the vertebrobasilar junction

BACKGROUND

The use of flow-diverters for non-saccular cerebral posterior circulation aneurysms requires complex deployment techniques and is associated with high mortality and morbidity. Therefore, further studies are required to clarify the effect of stenting on post-treatment hemodynamics in such aneurysms. In this study, we evaluated flow alterations in a treated giant fusiform aneurysm of the vertebrobasilar junction and correlated them with the clinical outcome.

METHODS

A patient-specific aneurysm model was acquired by rotational angiography, and three SILK flow-diverters (4.5 × 40, 5 × 40 and 5.5 × 40 mm) were virtually deployed in series along the basilar and right vertebral arteries. Image-based blood flow simulations before and after the treatment were performed under realistic pulsatile flow conditions. The flow reduction, velocity and wall shear stress (WSS) distribution, streamlines and WSS-derived parameters were evaluated before and after the treatment.

RESULTS

The computed velocity streamlines showed substantial alterations of the flow pattern in the aneurysm and successful redirection of blood flow along the series of flow-diverters with no flow through the overlapping stents. The obtained flow reduction of 86% was sufficient to create thrombogenic flow conditions. Moreover, a 6.2-fold increase in relative residence time and a decrease by 87% of time-averaged WSS contributed to a successful treatment outcome observed during the follow-up.

CONCLUSIONS

We found a correlation between the numerically predicted flow alterations and the available treatment outcome. This shows the potential of image-based simulations to be used in clinical practice for treatment planning and estimation of possible risk factors associated with a complex stent deployment in fusiform aneurysms of the posterior circulation.

In vitro investigation of chemical properties and biocompatibility of neurovascular braided implants

Braiding of Nitinol micro wires is an established technology for the manufacturing of fine-meshed neurovascular implants for tortuous vessel geometries. Electropolishing of wires before the braiding process has the potential to improve the in vitro behaviour in terms of thrombogenicity and endothelial cell proliferation. In this study, we present the first in vitro investigation of braided electropolished/blue oxide Nitinol samples in a blood flow loop, showing a significantly lower activation of the coagulation pathway (represented by the TAT III marker) and a tendency towards reduced platelet adhesion. Furthermore, we applied the same surface treatment on flat disks and measured protein adhesion as well as endothelial cell proliferation. We compared our results to non-electropolished samples with a native oxide surface. While platelet deposition was reduced on electropolished/blue oxide surface, a significant increase of endothelial cell seeding was observed. Investigation of inflammatory marker expression in endothelial cells provided divergent results depending on the marker tested, demanding closer investigation. Surface analysis using Auger electron spectroscopy revealed a thin layer mainly consisting of titanium oxynitride or titanium oxide + titanium nitride as a potential cause of the improved biological performance. Translated to the clinical field of intracranial aneurysm treatment, the improved biocompatibility has the potential to increase both safety (low thrombogenicity) and effectiveness (aneurysm neck reconstruction).

Long-term results of flow diversion in the treatment of intracranial aneurysms: a retrospective data analysis of a single center

PURPOSE

Endovascular techniques are frequently used for the treatment of intracranial aneurysms and flow diverter stents are relatively new and important devices in this field. The aim of our study is to report long-term follow-up results of flow diversion treatment.

METHODS

We retrospectively examined angiographic images and clinical reports of 133 patients (female, 112 [84%]; mean age, 46.3 years [range, 12-70 years]) who were treated with flow diverters between 2008 and 2013 and were followed up radiologically at least 1 year. The aneurysms treated with flow diverters were assessed according to technical problems, stent patency, residual filling, re-growth, and occlusion status, and the patients were assessed according to morbidity and mortality.

RESULTS

Except for ten patients, one aneurysm was treated per patient. Median duration of the follow-up was 927 days. Total occlusion rates in angiographic follow-up were found 76.2% for the sixth-month, 86.7% for the first-year, 93.6% for the third-year, 94.2% for the fifth-year, and 90.2% for entire follow-up period. Nine stent morphology changes were observed in the angiographic controls. Overall mortality and morbidity rates were 3.7% and 4.3%, respectively.

CONCLUSION

Despite technical difficulties and delayed hemorrhages, flow diverter stents are effective tools for the treatment of challenging aneurysms in the long run. Nonetheless, long-term results of flow diversion treatment must be evaluated hemodynamically and clinically in multicenter studies.

Endovascular treatment of visceral artery and renal aneurysms (VRAA) using a constant mesh density flow diverting stent

BACKGROUND

Flow diverting stents have been used safely and effectively for the treatment of intracranial aneurysms, particularly for large and wide necked aneurysms that are not amenable to conventional endovascular treatment with coiling. The Surpass Streamline device (Stryker Neurovascular, MI, USA) is a relatively new and unique flow diverting stent which maintains constant device mesh density over varying vessel diameters. This may potentially provide advantages compared to other flow diverting stents in achieving aneurysmal occlusion.

CASE PRESENTATION

Two patients with VRAA were treated using the Surpass Streamline device. The first patient was a 65-year-old male with an incidental 2.4 cm aneurysm originating from the hepatic artery near the gastroduodenal artery (GDA). The second patient was a 56-year-old male with an incidental 1.9 cm renal aneurysm arising from an anterior inferior segmental branch of the left renal artery. A Surpass flow diverting stent was used to successfully exclude the aneurysm neck in both cases. Reduced flow was achieved in one patient (equivalent to O'Kelly-Marotta [OKM] Grade B1). Preserved flow and stagnation (equivalent to OKM Grade A3) was achieved in the other. There was preserved distal flow in the parent arteries. No immediate complications were encountered in either case. Complete occlusion of both aneurysms was seen on follow up CT angiographic imaging within 8-weeks.

CONCLUSIONS

The Surpass flow diverting stent can be used safely and effectively to treat VRAA. It should be considered in unruptured large and giant wide necked VRAAs aneurysms. Additional large prospective studies are required for further validation.

On Flow Diversion: The Changing Landscape of Intracerebral Aneurysm Management

Uptake of flow-diverting technology is rapidly outpacing the availability of clinical evidence. Most current usage is off-label, and the endovascular community is nearer the beginning than the end of the learning curve, given the number of devices in development. A comprehensive overview of technical specifications alongside key outcome data is essential both for clinical decision-making and to direct further investigations. Most-studied has been the Pipeline Embolization Device, which has undergone a transition to the Pipeline Flex for which outcome data are sparse or heterogeneous. Alternative endoluminal devices do not appear to be outperforming the Pipeline Embolization Device to date, though prospective studies and long-term data mostly are lacking, and between-study comparisons must be treated with caution. Nominal technical specifications may be unrelated to in situ performance, emphasizing the importance of correct radiologic sizing and device placement. Devices designed specifically for bifurcation aneurysms also lack long-term outcome data or have only recently become available for clinical use. There are no major studies directly comparing a flow-diverting device with standard coiling or microsurgical clipping. Data on flow-diverting stents are too limited in terms of long-term outcomes to reliably inform clinical decision-making. The best available evidence supports using a single endoluminal device for most indications. Recommendations on the suitability and choice of a device for bifurcation or ruptured aneurysms or for anatomically complex lesions cannot be made on the basis of current evidence. The appropriateness of flow-diverting treatment must be decided on a case-by-case basis, considering experience and the relative risks against standard approaches or observation.

Periprocedural safety and technical outcomes of the new Silk Vista Baby flow diverter for the treatment of intracranial aneurysms: results from a multicenter experience

PURPOSE

The aim of our study was to assess the technical success and the safety of this new low-profile flow diverter Silk Vista Baby (SVB) by evaluating the intraprocedural and periprocedural complication rate.

MATERIAL/METHODS

Clinical, procedural, and angiographic data were analyzed.

RESULTS

41 consecutive patients (28 women; age average 50.5 years) with 43 aneurysms were treated with SVB. Aneurysm sizes were classified by their maximum diameter, with an average size of 9.5 mm (range 2-30 mm). Thirty-four cases were unruptured. five aneurysms previously ruptured, had recurrence after the initial coiling. There were two ruptured cases. Aneurysms' locations were: M1 segment (five cases), M2 segment (three cases), M3 segment (one case), middle cerebral artery (MCA) bifurcation (six cases), carotid-T (two cases), anterior communicating artery/A1/A2 (11 cases), pericallosal artery (four cases), supraclinoid ICA (two cases), PCom (one case), V4 segment (three cases), PCA (three cases), SCA (one case), and PICA (one case). We had five intraprocedural complications which resolved without clinical consequences and three events postprocedural events. Initial occlusion rates were: eight aneurysms (18.6%) were completely occluded, five aneurysms (11.6%) showed near-complete occlusion, four cases (9.3%) showed incomplete filling, and 26 cases (60.4%) showed persisting filling. The mRS score at discharge from the hospital did not change from the admission mRS score.

CONCLUSION

Our study demonstrated that the use of the new low-profile flow diverter, SVB device, for the treatment of intracranial aneurysms is feasible and technically safe.

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.

Delayed parent artery occlusions following use of SILK flow diverters for treatment of intracranial aneurysms

Background

The efficacy of SILK flow diverters (SFD) in the management of cerebral aneurysms has been established. However, the risk of complications with parent artery occlusion (PAO) remains to be fully elucidated. The purpose of our study was to analyze intracranial aneurysms treated with SFDs and assess for occurrences and potential risk factors for PAO.

Materials and methods

Between September 2010 and September 2017, 34 patients were treated for intracranial aneurysms using SFDs at a Canadian institution. This database was retrospectively analyzed for frequency of PAOs and statistical analysis performed for potential contributing factors.

Results

Following treatment with SFDs, average clinical and imaging follow-ups were 31 and 22 months, respectively. PAOs were identified in 21% (7/34) of patients and occurred between 8 days and 1.5 years from intervention but only in 11.8% in those compliant to anti-platelet medications. These were all associated with anterior circulation aneurysms (P=0.131) and had no associated neurological deficits. Of these, 57% (4/7) had a fusiform morphology compared with only 19% (5/27) in non-occluded patients (P=0.039). The presence of clinical symptoms at the time of initial SFD intervention was significantly associated with PAO (P=0.021).

Conclusion

Delayed PAO is not an uncommon outcome of flow diverter deployment and could be seen up to 1.5 years after treatment with no associated neurological deficits. Anti-platelet non-adherence remains a risk factor for PAO. Fusiform morphology of the aneurysm and symptoms at the time of intervention were associated with subsequent occlusion.

The occurrence of neointimal hyperplasia after flow-diverter implantation is associated with cardiovascular risks factors and the stent design

Background

Neo-intimal hyperplasia (NIH) is frequently observed after flow-diverter stent (FDS) implantation. Although mostly asymptomatic, this vascular response can sometimes lead to delayed ischemic strokes. This study intended to evaluate the factors potentially influencing the rates of NIH following FDS treatment.

Material and Methods

All aneurysm treatments performed with a Pipeline embolization device (PED) or a SILK stent from May 2011 to May 2015 were collected in a prospectively maintained database. Patient demographics, clinical, and angiographic outcomes including both digital subtraction angiography and C-arm cone-beam CT were registered. Two blind reviewers rated the presence of NIH on a binary scale (present/absent).

Results

From 148 patients, 63 datasets were available for analysis. Inter-reader agreement was excellent (Kappa=0.88). NIH was positively correlated with smoking, dyslipidemia, and high blood pressure, but not with aneurysm characteristics. At early follow-up (<12 months), NIH was more frequently associated with the use of the SILK stent (68%) rather than the PED (38%): P<0.02. At long-term follow-up, the NIH rate in the total population dropped from 55% to 26% with no more significant difference between the two stents. The complete occlusion rate as seen in early follow-up was higher in the SILK group with 76% vs 65% but without statistical significance (P=0.4).

Conclusion

NIH is a dual-vessel reaction after FDS implant. When planning a treatment in locations at risk of ischemic complications if severe NIH would occur, then the stent design should be considered. However, minimal NIH might also be needed as it is involved in aneurysm healing. Before treatment patients should be recommended best medical management of their cardiovascular risks factors to prevent an excessive NIH reaction.

SAFE study (Safety and efficacy Analysis of FRED Embolic device in aneurysm treatment): 1-year clinical and anatomical results

Background and purpose

Flow diversion is an innovative and increasingly used endovascular treatment for intracranial aneurysms. Its initial evaluation with the first devices available showed good efficacy of this treatment with variable safety results. The Flow Direction Endoluminal Device (FRED) has a specific design and was evaluated in a single-arm, multicenter, prospective, Good Clinical Practice study: SAFE (Safety and efficacy Analysis of FRED Embolic device in aneurysm treatment). This analysis reports clinical results at 1 year and anatomical results at 6 months and 1 year.

Methods

Patients with unruptured and recanalized aneurysms located in the anterior circulation treated with FRED and FRED Jr were prospectively included. A Clinical Event Committee and a Core Laboratory independently evaluated clinical outcome and anatomical results.

Results

Thirteen interventional neuroradiology centers included 103 patients/aneurysms. Aneurysm locations were supraclinoid internal carotid artery (ICA) in 71 (68.9%), cavernous ICA in 15 (14.6%), anterior cerebral or anterior communicating artery in 9 (8.7%), and middle cerebral artery in 8 (7.8%). Most aneurysms were small (<10 mm) in 71 patients (68.9%). Cumulative 1-year mortality and morbidity rates were 2/103 (1.9%) and 3/103 (2.9%), respectively, one death being related to cancer. At 1 year, anatomical results were: complete occlusion in 66/90 patients (73.3%), neck remnant in 7/90 patients (7.8%), and aneurysm remnant in 17/90 patients (18.9%).

Conclusions

SAFE study analysis at 1 year confirms the excellent safety profile of the FRED device for aneurysm treatment, with low morbidity and mortality rates (2.9% and 1.9%, respectively) and demonstrates its efficacy (adequate occlusion in 73/90 (81.1%)).

Clinical trial registration

Unique identifier: NCT02921698; Results.

Transient in-stent stenosis at mid-term angiographic follow-up in patients treated with SILK flow diverter stents: incidence, clinical significance and long-term follow-up

BACKGROUND

Little is known about in-stent stenosis (ISS) in patients with aneurysms treated with flow diverter (FD) stents. The reported incidence in the literature varies significantly.

OBJECTIVE

The aim of this study was to assess the incidence, severity, distribution, clinical significance, and possible predictors for ISS.

METHODS

Between July 2012 and June 2016 we retrospectively reviewed all patients treated with SILK FDs in our center. Only cases with short-term (4±2 months) and long-term (>1 year) follow-ups with digital subtraction angiograms were included. ISS was graded as mild (<25%), moderate (25-50%) or severe (>50%). The following predictors for ISS were assessed: gender, age, the presence of subarachnoid hemorrhage, aneurysm size, location, occlusion status, and post-stenting angioplasty.

RESULTS

Thirty-six patients met the inclusion criteria. At mid-term follow-up, ISS was observed in 16/36 patients (44%). Eleven patients (69%) had mild ISS, three (19%) moderate, and two (12%) severe ISS. ISS was diffuse in 11 patients (69%) and focal in five patients (31%). All patients were asymptomatic. Thirteen patients were maintained on dual antiplatelet therapy and three on aspirin alone. At long-term follow-up, complete ISS resolution was seen in 11 patients, improvement in three and worsening in two patients. No de novo ISS occurrence was observed. On univariate analysis there was no significant predictor for ISS.

CONCLUSIONS

Transient ISS after FD deployment is a common asymptomatic finding on mid-term angiographic follow-up. Complete resolution or improvement at long-term follow-up is seen in most patients who are maintained on dual antiplatelet therapy.

Silk flow-diverter stent for the treatment of complex intracranial aneurysms: A one-year follow-up multicenter study

Background Flow-diverter stents have been successfully used in the treatment of complex aneurysms with limited therapeutic alternatives. We report our experience using the Silk flow diverter (SFD; Balt Extrusion, Montmorency, France) for the treatment of complex aneurysms in four Argentine centers. Methods We conducted a retrospective review of 246 consecutive patients who were treated with the SFD at four Argentine centers between January 2009 and January 2017. The patient and aneurysm characteristics, as well as the details of the procedure, were analyzed. The angiographic and clinical findings were recorded during and immediately after the procedure and at 12-month follow-up. Results Angiography follow-up at 12 months was possible in 235 patients (95.5%) with 282 aneurysms. A total of 265 aneurysms (93.9%) presented with complete occlusion of the aneurysmal sac (class 1) and 17 aneurysms (6.1%) presented with partial occlusion (class 2). The 12-month clinical follow-up showed 11 patients with major events (seven, scale 2; five, scale 3; and two, scale 4). The morbidity and mortality rates were 4.2% (11/289) and 2.1% (5/289), respectively. Conclusions The treatment of aneurysms with the SFD was associated with a low rate of complications and a high percentage of aneurysmal occlusion. These findings suggest that SFD is an effective and safe alternative in the endovascular treatment of complex aneurysms.