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Background The treatment of posterior inferior cerebellar artery aneurysms is controversial. Recently, flow diverters have emerged as an attractive treatment option. Here, we performed a systematic review and meta-analysis of the angiographic and clinical outcomes of flow diverter-treated posterior inferior cerebellar artery aneurysms. Methods We searched the PubMed, EMBASE and Web of Science databases for studies published from inception to January 2021. We included studies that described flow diverters procedures for posterior inferior cerebellar artery aneurysms with ≥2 patients. The outcomes were the complete occlusion rate and flow diverter-related complication rate. Meta-analysis was performed using a random or fixed effects model based on heterogeneity. Results We included six studies involving 46 posterior inferior cerebellar artery aneurysms. There were 14 ruptured aneurysms. All flow diverters were successfully released and the technical success rate was 100%. The complete occlusion rate was 81% (95% confidence interval = 65–93%; I2 = 0.00%; P 2 = 0.00%; P 2 = 0.00%; P = 0.951). Conclusions Treatment of posterior inferior cerebellar artery aneurysms with flow diverters is feasible and carries a high degree of technical success. However, this treatment is underutilized in patients with posterior inferior cerebellar artery aneurysms due to a higher complication rate and lower occlusion rate compared with clipping and traditional endovascular treatment. Further well-designed prospective and randomized studies are required to fully understand the effects of flow diverters especially in posterior inferior cerebellar artery aneurysms patients requiring endovascular treatment.

BackgroundOptical coherence tomography (OCT) is an ultra-high resolution real-time intravascular imaging method that is gaining interest in cerebrovascular applications.ObjectiveTo compare, in a rabbit elastase aneurysm model, digital subtraction angiography (DSA) and OCT as diagnostic tools for the assessment of aneurysmal remnants and baseline characteristics of aneurysms after flow diverter (FD) implantation.MethodsWith Institutional Animal Care and Use Committee approval, saccular aneurysms were created in 28 rabbits and treated with Derivo FDs. DSA was performed before, and immediately after, stent implantation. As a follow-up, DSA and OCT were performed 28 days after device implantation.ResultsDSA and OCT were successfully performed in 23 cases. OCT could not be achieved in 5 cases owing to navigational difficulties in the stent lumen with the OCT catheter. Residual aneurysms were significantly more often visible with OCT (18/23 (78%) than with DSA 12/23 (52%), p = 0.031).ConclusionOCT was more sensitive than conventional angiography for the assessment of residual aneurysms at 28 days after FD implantation in an animal model.

Background and purpose. - Several studies have reported good long-term results in the occlusion of intracranial aneurysms with flow diverter treatment. The aim of this study was to report the safety and six-month follow-up outcomes using the new Surpass Evolve flow diverter in the treatment of intracranial aneurysms. Materials and methods. - Consecutive patients with intracranial aneurysm treated with Surpass Evolve flow diverter in two high-volume neurovascular centers between May 2019 and January 2020 were retrospectively reviewed. Procedure-related complications, aneurysm occlusion (O'Kelly-Marotta grading scale), and clinical outcomes were assessed. Results. - Twenty-nine patients with 30 aneurysms were included in the study. Favorable aneurysm occlusion (O'Kelly Marotta grading scale C-D) at six-month follow-up was achieved in 21/27 (78%) aneurysms. No clinical procedure related thromboembolic complications were encountered. Twenty-three out of 24 patients with unruptured aneurysms treated with Surpass Evolve remained clinically intact at clinical follow-up. There was one fatal hemorrhagic procedure-related complication (3%). In five patients with ruptured aneurysms, no early or late rebleeds occurred from the aneurysms. Conclusions. - Surpass Evolve FD worked technically well with no intraprocedural thromboembolic complications and occlusion rates comparable to other FDs. (c) 2021 L'Auteur(s). Publie par Elsevier Masson SAS. Cet article est publie en Open Access sous licence CC BY (http://creativecommons.org/licenses/by/4.0/).

Flow diverter (FD) therapy using Pipeline embolization device (PED) has become an important alternative to treat internal carotid artery (ICA) aneurysms. Herein, we report the long-term outcome for 3 years after FD therapy using PED for ICA aneurysms in Japan. The patients who underwent angiographical and/or clinical follow-up for 3 years after the FD therapy using PED of large or giant unruptured ICA aneurysms from December 2012 at our university hospital are the subjects of this study. We retrospectively reviewed the in- and outpatients’ medical charts, and written operative and radiological records. There were 84 patients with 90 aneurysms who could be clinically and/or angiographically followed up for 3 years. Of these, 7 aneurysms were only available for clinical follow-up. Of the remaining 83 aneurysms, 6 aneurysms had vessel occlusion due to stent thrombosis or parent artery occlusion, and 60 of the remaining 77 (77.9%) had complete occlusion. In multivariate analysis, older age (>70 years), wide neck, and non-adjunctive coiling contributed statistically significantly to incomplete occlusion. Of the 84 patients, 2 patients (2.4%) had delayed complications between 6 months and 3 years after the initial FD placement. Three patients (3.6%) had poor outcome due to postoperative major stroke complications, 2 of which were acute complications. The long-term results after FD therapy are good both angiographically and clinically. Endothelialization of the aneurysmal neck and intra-aneurysmal thrombosis contribute to complete occlusion. The primary reason for the somewhat low complete occlusion in Japan may be the patients are generally older.

BackgroundScientific data on the safety and efficacy of flow diverter stents (FDS) for the treatment of unruptured internal carotid artery (ICA) aneurysms with compressive neuro-ophthalmological symptoms are scarce. We studied this subject in a retrospective international multicenter series, pooling data of 9 tertiary care neurointerventional departments.ObjectiveTo investigate, in a retrospective, multicentric cohort of patients presenting with visual or oculomotor symptoms attributed to a compressive carotid artery in an unruptured intracranial aneurysm, the safety and efficacy profiles of FDS, by analyzing neuro-opthalmologic symptom evolution following FDS placement, complications, and aneurysm obliteration rates.MethodsAll patients treated since 2015 with a FDS for an unruptured aneurysm of the ICA with signs of compressive cranial nerve symptoms (CN II, III, IV, VI) were included.ResultsWe treated 55 patients with 55 aneurysms; 21 (38.2%) patients had oculomotor and 15 (27.3%) visual symptoms only; 19 (34.5%) presented with a combination of both. Treatment-related morbidity/mortality occurred in 7.2% and 3.6%, respectively. At last imaging follow-up (13.1±10.5 months) rates of complete aneurysm occlusion, neck remnant, and aneurysm remnant were 72%, 14%, and 14%, respectively. At last clinical follow-up after 13±10.5 months, 19/51 (37.3%) patients had recovered completely and 18/51 (35.3%) had recovered at least partially from their neuro-ophthalmological symptoms. In multivariable models, a longer delay between symptom onset and treatment was associated with higher odds for incomplete recovery and lower odds for any improvement (aOR 1.03 (95% CI 1.01 to 1.07), p=0.047 and 0.04 (0–0.81), p=0.020). Incomplete recovery was independently associated with older age and fusiform aneurysms.ConclusionFDS are effective to treat patients with compressive aneurysms of the ICA causing neuro-ophthalmological symptoms, especially when treatment is initiated early after symptom onset, and aneurysm occlusion is adequate. However, serious complications are not rare.

BACKGROUND AND PURPOSE: Intracranial stents for the treatment of aneurysms can be responsible for parent artery straightening, a phenomenon with potential consequences for aneurysmal occlusion. We aimed to evaluate parent artery straightening following flow-diverter stent placement in patients with intracranial aneurysms and explored the association between parent artery straightening and subsequent aneurysm occlusion. MATERIALS AND METHODS: All patients treated with flow-diverter stents for anterior circulation aneurysms located downstream from the carotid siphon between January 2009 and January 2018 were screened for inclusion. Parent artery straightening was defined as the difference (α–β) in the parent artery angle at the neck level before (α angle) and after flow-diverter stent deployment (β angle). We analyzed the procedural and imaging factors associated with parent artery straightening and the associations between parent artery straightening and aneurysmal occlusion. RESULTS: Ninety-five patients met the inclusion criteria (n = 64/95 women, 67.4%; mean age, 54.1 [SD, 11.2] years) with 97 flow-diverter stents deployed for 99 aneurysms. Aneurysms were predominantly located at the MCA bifurcation (n = 44/95, 44.4%). Parent artery straightening was found to be more pronounced in patients treated with cobalt chromium stents than with nitinol stents (P = .02). In multivariate analysis, parent artery straightening (P = .04) was independently associated with aneurysm occlusion after flow-diverter stent deployment. CONCLUSIONS: The use of flow-diverter stents for distal aneurysms induces a measurable parent artery straightening, which is associated with higher occlusion rates. Parent artery straightening, in our sample, appeared to be more prominent with cobalt chromium stents than with nitinol stents. This work highlights the necessary trade-off between navigability and parent artery straightening and may help tailor the selection of flow-diverter stents to aneurysms and parent artery characteristics.

Background Open surgery has traditionally been preferred for the management of bifurcation middle cerebral artery (MCA) aneurysms. Flow diverting stents present a novel endovascular strategy for aneurysm treatment. Objective To add to the limited literature describing the outcomes and complications in the use of flow diverters for the treatment of these complex aneurysms. Methods This is a multicenter retrospective review of MCA bifurcation aneurysms undergoing flow diversion. We assessed post-treatment radiological outcomes and both thromboembolic and hemorrhagic complications. Results We reviewed the outcomes of 54 aneurysms treated with flow diversion. Four (7.4%) of the aneurysms had a history of rupture (3 remote and 1 acute). Fourteen (25.9%) of the aneurysms already underwent either open surgery or coiling prior to flow diversion. A total of 36 out of the 45 aneurysms (80%) with available follow-up data had adequate aneurysm occlusion with a median follow-up time of 12 mo. There were no hemorrhagic complications but 16.7% (9/54) had thromboembolic complications. Conclusion Flow diverting stents may be a viable option for the endovascular treatment of complex bifurcation MCA aneurysms. However, compared to published series on the open surgical treatment of this subset of aneurysms, flow diversion has inferior outcomes and are associated with a higher rate of complications.

BACKGROUND Management of complex thrombosed aneurysms of the middle cerebral artery (MCA) is challenging. Lesions not amenable to endovascular techniques or direct clipping might require a bypass procedure with subsequent aneurysm occlusion. Various bypass techniques followed by surgical or endovascular closure of the aneurysm are available, but an unpredictable extension of the thrombus to the parent vessel and/or to perforator vessels can occur. We present a multidisciplinary technique with the aim to reduce invasiveness and complications. METHODS We present two patients, harboring a thrombosed giant MCA bifurcation aneurysm, who were treated with a minimally invasive three-steps multimodality procedure. In both cases, through a limited exposure of the sylvian fissure, a side-to-side anastomosis between the two M2 branches was performed, followed in the immediate post-op by an endovascular occlusion of the frontal M2 branch, with the aim of transforming a bifurcation aneurysm in a sidewall aneurysm, that was then treated a few days later by flow diverter deployment. RESULTS Both patients had excellent outcomes and were discharged after 7 days without neurological deficits. CONCLUSIONS Treatment of complex thrombosed MCA aneurysms is challenging. Side- to-side M2 anastomosis with the aim of transforming a bifurcation aneurysm in a sidewall aneurysm, suitable to be treated few days later by flow diverter deployment, offers a minimally invasive multimodal approach with the possibility of reducing serious complications.

BACKGROUND AND PURPOSE: Identifying and predicting which aneurysms are likely to quickly occlude and which ones are likely to remain open following treatment with flow-diverting devices is important to develop optimal patient management strategies. The purpose of this study was to evaluate predictions based on computational fluid dynamics models using the elastase rabbit aneurysm model. MATERIALS AND METHODS: A series of 13 aneurysms created in rabbits were treated with flow diverters, and outcomes were angiographically assessed at 8 weeks’ follow-up. Computational fluid dynamics models were constructed from pretreatment 3D rotational angiograms and Doppler ultrasound flow velocity measurements. Postimplantation mean aneurysm inflow rate and flow velocity were used to prospectively predict aneurysm occlusion blinded to the actual outcomes. Specifically, if both variables were below their corresponding thresholds, fast occlusion was predicted, while if one of them was above the threshold, slow or incomplete occlusion was predicted. RESULTS: Of the 13 aneurysms included, 8 were incompletely occluded 8 weeks after treatment, and 5 were completely occluded. A total of 10 computational fluid dynamics–based predictions agreed with the angiographic outcome, reaching 77% accuracy, 80% sensitivity, and 75% specificity. Posttreatment mean velocity alone was able to achieve the same predictive power as the combination of inflow rate and velocity. CONCLUSIONS: Subject-specific computational fluid dynamics models of the hemodynamic conditions created immediately after implantation of flow-diverting devices in experimental aneurysms created in rabbits are capable of prospectively predicting, with a reasonable accuracy, which aneurysms will completely occlude and which ones will remain incompletely occluded.

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. 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. 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%). 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.

Background The p64MW HPC and p48MW HPC flow diverters have reduced thrombogenicity due to hydrophilic coating. The purpose of this study was to evaluate its safety and efficacy in Mongolian patients under single antiplatelet therapy (SAPT) with prasugrel. Materials and methods We performed a retrospective review of patients enrolled into our prospectively maintained database to identify all patients treated with either the p48MW HPC or p64MW HPC under SAPT. We recorded baseline demographics, aneurysm size and location, procedural complications, angiographic and clinical results. Results 24 patients, (female = 21, 87.5%), age 48.2 ± 11.6 years (range 25–63) underwent treatment of 30 aneurysms with either p64MW HPC or p48MW HPC. All aneurysms were saccular with dome width 8.2 ± 6.5 (range 1.6–26.0 mm) and dome height 7.6 ± 6.7 (range 1.6–30.0 mm). None of the aneurysms were previously treated. The average PRU was 54.6 ± 31.2 (range 1–127) on pre-operative VerifyNow testing. Angiographic follow-up was available for 13 patients (17 aneurysms), 183 ± 36 days post-procedure, at which point 64.7% of aneurysms (n = 11/17) were completely occluded and 11.8% (n = 2/17) had only neck remnants resulting in 76.5% of aneurysms being adequately occluded A single intra-operative complication (4.2%) occurred however all patients were mRS ≤1 at last follow-up. There were two post-operative complications neither of which resulted in permanent neurological morbidity. There were no instances of post-operative aneurysmal rupture or delayed parenchymal haemorrhage. The overall mortality was 0%. Conclusion The efficacy and safety of p64MW HPC coated devices under SAPT is similar to uncoated flow diverters that require DAPT.

An unruptured aneurysm is often asymptomatic or present without neurological deficits, causing severe morbidity. However, the potential of this defect to rupture requires proper management. Herein, we report a case of an unruptured saccular aneurysm of the ophthalmic artery with initial clinical seizures. The patient was treated by flow diversion which redirects the blood flow that normally leads to the protrusion of the aneurysm back to the main vessel. Flow diversion is chosen because it is less risky and has a faster recovery time than other treatment options, but it is more expensive than others. Although this technology is not new, there is no report on its implementation in Indonesia. The patient was prescribed antiplatelet treatment for at least 6 months post-treatment, then she showed no sign of seizure or new focal neurological deficits 4 months post-treatment. The patients were expected to undergo digital subtraction angiography evaluation 6 months after flow diversion treatment, but it has not been performed due to the coronavirus disease 2019 pandemic.

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 ± 7.1 mm) 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.

BackgroundUsing 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.MethodsFifteen 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).ResultsOverall, 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.ConclusionsThe 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.

BackgroundAlthough coiling with a flow diverter may provide immediate dome protection, no studies have evaluated the effect on complications of postoperative occlusion degree immediately postoperatively. The purpose of this study was to determine whether postoperative occlusion degree immediately after flow-diverter placement with adjunctive coiling was associated with complications.MethodsAll patients’ data were collected from the post-market multi-center cohort study of embolization of intracranial aneurysms with a pipeline embolization device (PED) in China (PLUS) registry. We divided patients into those treated with a PED alone (PED-only (PO) group), those treated with a PED with coils and incomplete occlusion (PED + coils + incomplete occlusion (PCIO) group), and those treated with a PED with coils and complete occlusion (PED + coils + complete occlusion (PCCO) group).ResultsWe evaluated 1171 consecutive patients with 1322 aneurysms treated with a PED: 685 aneurysms were treated with PO, 444 with PCIO, and 193 with PCCO. The PCCO group had a higher rate of aneurysm occlusion at the last follow-up than the PCIO and PO groups (PConclusionsAlthough postoperative complete occlusion with a PED and adjunctive coiling can increase the rate of aneurysm occlusion, this approach may also increase the risk of ischemic stroke and lead to poor postoperative functional outcomes.

Introduction: Flow diverters such as the pipeline embolization device (PED) cause hemodynamic changes of the treated vessel segment. In posterior communicating artery (PcomA), aneurysms’ unique anatomic consideration have to be taken in account due to the connection between the anterior and posterior circulation. We hypothesize that in conjunction with PcomA remodeling, there will also be remodeling of the ipsilateral P1 segment of the posterior cerebral artery (PCA) after PED treatment for PcomA aneurysms. Methods: We retrospectively collected radiological as well as clinical data of PcomA aneurysm patients treated with PED including PcomA and P1 vessel diameters before and after treatment as well as patient and aneurysm characteristics. Results: Overall, 14 PcomA aneurysm patients were included for analysis and PED treatment was performed without complications in all patients. In 10 out of 14 patients (71%), a decrease in PcomA diameter was observed and there was a significant mean decrease of 0.78 mm in PcomA diameter on angiographic last follow-up (LFU) (p = 0.003). In the same patient population (10 out of 14 patients), there was meanwhile a significant mean increase of 0.43 mm in the ipsilateral P1 segment diameter observed (p = 0.015). These vessel remodeling effects were in direct correlation with aneurysm occlusion since all of these patients showed aneurysm occlusion at LFU while 29% showed only partial occlusion without vessel remodeling effects. A decrease in PcomA diameter was directly associated with aneurysm occlusion (p = 0.042). There were no neurologic complications on LFU. Conclusion: In the treatment of PcomA aneurysms with PED, the P1 segment of the PCA increases in diameter while the PcomA diameter decreases. Our results suggest that this remodeling effect is associated with aneurysm occlusion and decrease of PcomA is hemodynamically compensated for by an increase in the ipsilateral P1 diameter.

Purpose We aimed to assess the efficacy and safety of flow-diverter stents (FDs) in the management of posterior circulation cerebral aneurysms and compare FD efficacy between anterior and posterior circulation aneurysms. Methods We searched the PubMed, Scopus, Cochrane, and Web of Science databases for relevant studies through March 2020. Studies assessing FDs for posterior circulation aneurysms that included ≥20 treated aneurysms were included. Moreover, the studies compared FD efficacy between anterior and posterior circulation aneurysms were included. Data regarding angiographic aneurysmal occlusion, procedural complications, mortality, and morbidity were extracted and pooled in a random-effects meta-analysis model. Results Fourteen studies with a total of 659 patients and 676 posterior circulation aneurysms were included. The pooled rate of aneurysmal occlusion at long-term angiographic follow-up was 78% [95% confidence interval (CI), 71–85]. The pooled rates of intraparenchymal hemorrhage, ischemia, and procedure-related mortality and neurological morbidity were 2%, 8%, 7%, and 6%, respectively. Complete occlusion occurred in 82.4% of the posterior circulation aneurysm subgroup and 77.5% of the anterior circulation aneurysm subgroup. The difference was not significant (relative risk 1.01; 95% CI, 0.86–1.19; p = 0.91). Regression analysis showed that elderly patients and females had higher morbidity. Conclusion Posterior circulation aneurysms can be effectively treated with FDs with comparable occlusion rates to those in anterior circulation aneurysms. However, periprocedural complications are not negligible.

Pericallosal artery aneurysm (PAA) is a relatively uncommon type of intracranial aneurysm that tends to rupture more frequently and cause higher mortality rates than other types of cerebral aneurysms. Surgery to address PAA is difficult due to its deep-seated location, the size of the aneurysmal sac, and the limited surgical field. In recent years, with the development of percutaneous interventions, endovascular treatment has become the preferred, minimally invasive intervention method for the treatment of pericallosal aneurysms. In this article, we present a case of PAA that was successfully treated with flow diversion therapy in a 51-year-old male.

BackgroundFlow diverters (FDs) are effective in the treatment of carotid aneurysms. Compared with carotid aneurysms, the treatment of distal intracranial aneurysms with FDs has been associated with a relatively high incidence of complications. Low thrombogenic modified-surface FDs may reduce ischemic complications and allow for the use of a single antiplatelet medication. The aim of this study was to assess the safety and efficacy of the p48 MW HPC Flow Modulation Device (Phenox GmbH, Bochum, Germany) to treat distal intracranial aneurysms used in combination with prasugrel monotherapy.MethodsThis was a single-center, prospective, pivotal, open, single-arm study. Patients were included in this study from December 2019 to September 2020. The primary endpoints were the incidence of any neurologic deficit after treatment until 1 month of follow-up, defined as National Institutes of Health Stroke Scale (NIHSS) ≥1, and the incidence of acute ischemic lesions in magnetic resonance imagin (MRI) images 48 hours after treatment. The secondary endpoint was the rate of complete occlusion of the aneurysms at the 1-month follow-up.ResultsTwenty-one patients harboring 27 distal aneurysms of the anterior circulation were included. Mean age was 57.8 (SD 9.7) years, and 16 patients were female (80%). No patient had neurologic symptoms at the 1-month follow-up. Four patients (20%) had asymptomatic acute brain ischemic lesions on MRI. Complete aneurysm occlusion occurred in 9/27 (33.3%) aneurysms at the 1-month follow-up.ConclusionIn this pilot safety trial, treatment of distal intracranial aneurysms with p48 MW HPC under monotherapy with prasugrel appeared to be safe.

Background and purpose Flow diverters are increasingly used to treat intracranial aneurysms. We report the safety and efficacy of the p64 flow diverter, a resheathable and detachable device for intracranial aneurysms. Materials and methods We retrospectively reviewed 108 patients with 109 aneurysms treated with the p64 between March 2014 and July 2019. There were 87 women and 21 men, mean age 57 years. Of 109 aneurysms, 74 were discovered incidentally, 12 were symptomatic, 18 were previously treated, and five were ruptured dissection aneurysms. A total of 10 aneurysms were located in the posterior circulation. The mean aneurysm or remnant size was 8.1 mm. Results Hemorrhage by perforation with the distal guidewire occurred in two patients with permanent neurological deficits in one. In one patient, acute in-stent occlusion caused infarction with a permanent deficit. Permanent morbidity was 1.9% (2 of 108, 95%CI 0.1–6.9%); there was no mortality. During follow-up, three in-stent occlusions occurred, all asymptomatic. There were no delayed hemorrhagic complications. At six months, 77 of 96 aneurysms (80.2%) were completely occluded, and at last follow-up, this increased to 93 of 96 aneurysms (96.9%). In-stent stenosis at any degree occurred in 11 patients, progressing to asymptomatic complete occlusion in one. In the other patients, stenosis resolved or improved at further follow-up. Conclusion The p64 offers an effective and safe treatment option. Aneurysm occlusion rate was 97% at last follow-up, mostly achieved with a single device. There were no delayed hemorrhagic complications. Delayed in-stent stenosis infrequently progresses to occlusion but remains a matter of concern.

Background Flow diverters are novel, contemporary tools in treating intracranial aneurysms. There is rapid publication turnover, with newer devices introduced and expanding indications. The bibliometric analysis measures the impact of particular articles and summarizes the chronologic trends overall. Methods In July 2020, we performed a thorough search of the Scopus database using the terms “flow diversion,” “flow diverter,” and “flow diverting stent.” The top 100 most impactful articles were arranged based on citation count in descending order. The collected articles were then analyzed with an assessment of relevant factors. Results Almost 1671 articles were published between 2007 and 2020. The gathered top 100 most-cited articles amassed 10,035 citations, with an average citation count of 100.35. An 8.8% self-citation rate was identified for all authors. The publication trends peaked in 2012, in which 24% of articles were published. Most prolific categories with top citations are on pipeline embolization, followed by the SILK flow diverter category. The United States published the highest number of articles. The University of Buffalo and Mayo Clinic published most of the articles among other institutions. American Journal of Neuroradiology was the most productive journal by producing 28 articles. Conclusions This bibliometric analysis shows significant chronologic trends, with a shift from usefulness and outcome to short-term and long-term complications. Areas to improve in flow diverter research can be addressed after this analysis of the most impactful articles on this topic.

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.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.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.

BACKGROUND AND PURPOSE: Transradial access for neurointerventional procedures has been proved a safer and more comfortable alternative to femoral artery access. We present our experience with transradial (distal radial/anatomic snuffbox and radial artery) access for treatment of intracranial aneurysms using all 3 FDA-approved flow diverters. MATERIALS AND METHODS: This was a high-volume, dual-center, retrospective analysis of each institution’s data base between June 2018 and June 2020 and a collection of all patients treated with flow diversion via transradial access. Patient demographic information and procedural and radiographic data were obtained. RESULTS: Seventy-four patients were identified (64 female patients) with a mean age of 57.5 years with a total of 86 aneurysms. Most aneurysms were located in the anterior circulation (93%) and within the intracranial ICA (67.4%). The mean aneurysm size was 5.5 mm. Flow diverters placed included the Pipeline Embolization Device (Flex) (PED, n = 65), the Surpass Streamline Flow Diverter (n = 8), and the Flow-Redirection Endoluminal Device (FRED, n = 1). Transradial access was successful in all cases, but femoral crossover was required in 3 cases (4.1%) due to tortuous anatomy and inadequate support of the catheters in 2 cases and an inability to navigate to the target vessel in a patient with an aberrant right subclavian artery. All 71 other interventions were successfully performed via the transradial approach (95.9%). No access site complications were encountered. Asymptomatic radial artery occlusion was encountered in 1 case (3.7%). CONCLUSIONS: Flow diverters can be successfully placed via the transradial approach with high technical success, low access site complications, and a low femoral crossover rate.

Endovascular treatment of unruptured intracranial aneurysms may increase cerebral microbleeds (CMBs) in postprocedural T2*-weighted MRIs, which may be a risk for future intracerebral hemorrhage. This study examined the characteristics of postprocedural CMBs and the factors that cause their increase. The patients who underwent endovascular treatment for unruptured intracranial aneurysms from April 2016 to February 2018 were retrospectively analyzed. Treatment techniques for endovascular treatment included simple coiling, balloon-assisted coiling, stent-assisted coiling, or flow diverter placement. To evaluate the increase in CMBs, a head MRI including diffusion-weighted imaging and T2*-weighted MRIs was performed on the preprocedural day; the first postprocedural day; and at 1, 3, and 6 months after the procedure. Among the 101 aneurysms that were analyzed, 38 (37.6%) showed the appearance of new CMBs. In the multivariate analysis examining the causes of the CMB increases, chronic kidney disease, a higher number of preprocedural CMBs, and a higher number of diffusion-weighted imaging–positive lesions on the first postprocedural day were independent risk factors. Furthermore, a greater portion of the increased CMBs was found in cortical and subcortical lesions of the treated vascular perfusion area within 1 month after the procedure. In endovascular treatment for unruptured intracranial aneurysms, CMBs tended to increase in patients with small vessel disease before the procedure, and it was also implicated in hemorrhagic changes after periprocedural microinfarction.

The authors report a rare autopsy case. A 59-year-old woman underwent flow diverter (FD) therapy using a pipeline embolization device (PED) for a large paraclinoid internal carotid artery aneurysm. Follow-up magnetic resonance (MR) examinations were performed 6 months after the treatment. Although the T2-weighted images showed progressive thrombosis of the aneurysm, the silent MR angiography (MRA) clearly showed the residual blood flow within the aneurysm. The patient committed suicide 2 months after the follow-up MR examinations. An autopsy specimen showed a small section of the defective membranes with the PED that matched the entry point of residual blood flow seen clearly in the silent MRA. Macroscopic photograph and hematoxylin and eosin stained sections showed defective endothelialization. In contrast, complete endothelialization was observed in membranes covering the PED. The autopsy findings after FD therapy showed defective endothelialization that perfectly matched and corroborated the silent MRA findings.

The carotid sinus reflex (CSR) is a rare complication of the Pipeline Embolization Device (PED) deployment. No study has assessed the potential risk factors in a case series. The purpose of this study was to examine CSR triggering during PED deployment. Thirty-seven consecutive patients who underwent PED deployment were included. All procedures were performed under local anesthesia with mild sedation. We retrospectively analyzed patient characteristics, PED deployment time, and vital signs during the procedure. The vital signs included the pulse rate (PR) and systolic blood pressure (SBP) obtained at three timepoints (pre-deployment, during deployment, post-deployment). We examined the triggering of the CSR during PED deployment by comparing the vital signs at the three timepoints. Moreover, risk factors for CSR were analyzed with univariate analysis. The patients' average age was 66.3 years. The average size of the aneurysm was 18.0 mm. Six patients (16.2%) showed a decline in the SBP or PR defined as CSR. One patient had a transient cardiac arrest and two had severe transient bradycardia. Deployment into the ophthalmic segment of the internal carotid artery (C2 segment) aneurysm (p = 0.022), prolonged PED deployment time more than 14.5 minutes (p = 0.005), and an acute angle of the anterior genu less than 51.5 degrees (p = 0.005) were risk factors in triggering CSR. CSR may be triggered during PED deployment under local anesthesia with mild sedation. Deployment to the C2 segment aneurysm, prolonged PED deployment time, and an acute angle of the anterior genu were associated with CSR triggering.

Background The Tubridge™ flow diverter (TFD) was recently developed in China; however, its safety and efficacy in treating large cavernous carotid artery aneurysms (LCCAs) are unclear. Our objective was to evaluate the safety and efficacy of the TFD in patients receiving TFDs to treat LCCAs (10–25 mm). Methods Between June 2013 and May 2014, seven patients with LCCAs were enrolled in our study, and all seven patients underwent TFD implantation combined with coils. Results Angiographic follow-up images were available for all seven patients at a median of 57.5 ± 16.7 (range, 6–69) months. Seven patients obtained favorable angiographic results defined as O’Kelly–Marotta Scale C and D. Clinical follow-up data were available for all seven patients at a median of 73.32 ± 3.6 (range, 66–78) months. No patients developed new neurological deficits. Six patients achieved a modified Rankin scale score of 0, and diplopia improved in the remaining patient. Conclusions The results were excellent for the aneurysms treated with TFDs in our patients with LCCAs. TFDs are feasible for the treatment of LCCAs, but a multicenter, controlled clinical trial is needed to evaluate the long-term safety and efficacy of the TFD to treat LCCAs.

Persistent primitive trigeminal artery (PPTA) is the most common primitive carotid-basilar anastomosis, and it is associated with cavernous aneurysms. Because aneurysms are supplied blood by both the internal carotid artery (ICA) and PPTA, the PPTA should be occluded for successful flow diverter treatment. Here, we report a successful case of endovascular treatment for a PPTA aneurysm using flow diverter and antegrade-retrograde coil embolization. Our case findings demonstrated that the occlusion of PPTA should be performed for a greater chance of successful flow diversion.

Background The novel low-profile p48 flow diverter has been designed to treat aneurysms on small vessels of 1.75–3mm. We report our first clinical experiences. Methods Between March 2018–January 2020, 22 patients with 25 aneurysms were treated with the p48 in 3 centers. One patient had 3 aneurysms covered by one p48 and one patient had 2 aneurysms. There were 5 men, 17 women, with a mean age of 55 years (median 59, range 29–73 years). Results In 25 aneurysms, 24 p48 flow diverters were placed. In 1 patient additional coils were placed in the aneurysm. Procedural vessel rupture by the micro guidewire occurred in 2 patients and vessel rupture during p48 balloon dilatation occurred in 1 patient. Overall, the permanent morbidity rate was 13.6% (3 of 22, 95%CI 3.9–34.2%) and mortality was 4.5% (1 of 22, 95%CI Conclusions Treatment of aneurysms in small-caliber vessels with the p48 is feasible and effective but is not without complications. More data is needed to establish indications, safety, and efficacy more accurately.

BACKGROUND: Flow diverters (FDs) are an excellent option for the management of giant carotid artery aneurysms. However, in a nonnegligible percent of cases, the aneurysm may continue to grow despite multiple endovascular treatments and apparent occlusion on the angiogram. Due to the recent introduction of FDs, surgical experience after their failure is scarce and neurosurgeons have to face these challenging cases without much previous reference. Here we describe a giant ophthalmic-carotid aneurysm that presented with new severe mass effect 5 years after initially successful treatment with FDs and coils. We investigate the likely advantages of partial trapping versus complete trapping in this particular type of case. CASE DESCRIPTION: A 63-year-old patient with a subarachnoid hemorrhage from a 26-mm left carotid-ophthalmic aneurysm was initially embolized with coils. One year later a recanalization was observed and treated with an FD. Five years afterward, the patient's mild cognitive impairment prompted a magnetic resonance image that showed significant aneurysm growth despite apparent occlusion on angiogram. Rescue surgery consisted of partial trapping + extracranial-intracranial bypass and aneurysm debulking. The patient recovered from his deficits and remains asymptomatic 2 years later. CONCLUSIONS: In selected patients with previous long-term FDs, partial trapping may be a choice even if aneurysm debulking is needed. After years of stent placement, some endothelialization and neointimal membrane formation could have a summing effect to facilitate surgical exclusion and enable a safe thrombectomy. Classic revascularization techniques must be rethought and retested in this new FD era scenario.

A flow diverter can be used to treat a ruptured aneurysm, especially during complicated cases for endovascular or open microsurgical procedures. However, some complications have been reported such as occlusion of side branches or perforating arteries, stent migration or improper stent position, re-rupture of the aneurysm, and in-stent thrombosis. A 38-year-old man diagnosed with a ruptured left supraclinoid aneurysm was treated with a Pipeline embolization device. Despite adequate stent coverage of the aneurysmal neck, delayed proximal migration was seen in follow-up imaging. To our knowledge, proximal migration of the stent mostly happens intraoperatively due to an undersized stent or excessive stretching. We report a case of delayed proximal flow diverter stent migration.

IntroductionDespite a decade of research into virtual stent deployment and the post-stenting aneurysmal hemodynamics, the hemodynamic factors which correlate with successful treatment remain inconclusive. We aimed to examine the differences in various post-treatment hemodynamic parameters between successfully and unsuccessfully treated cases, and to quantify the additional flow diversion achievable through stent compaction or insertion of a second stent.MethodsA systematic review and meta-analysis were performed on eligible studies published from 2000 to 2019. We first classified cases according to treatment success (aneurysm occlusion) and then calculated the pooled standardized mean differences (SMD) of each available parameter to examine their association with clinical outcomes. Any additional flow diversion arising from the two common strategies for improving the stent wire density was quantified by pooling the results of such studies.ResultsWe found that differences in the aneurysmal inflow rate (SMD −6.05, 95% CI −10.87 to −1.23, p=0.01) and energy loss (SMD −5.28, 95% CI −7.09 to −3.46, pConclusionsInflow rate and energy loss have shown promise as identifiers to discriminate between successful and unsuccessful treatment, pending future research into their diagnostic performance to establish optimal cut-off values.

Flow diverter devices have become a routine first-line option for treatment of an increasing population of intracranial aneurysms at many neurovascular centers. Despite the promising results of flow diverter stents on anterior circulation, incomplete occlusion on the presence of fetal posterior circulation has been described on several reports. Here we describe a novel technical alternative to conventional flow diversion approach for this specific subgroup of aneurysms using the low-profile flow diverter, Silk Vista Baby. The device was selectively placed into the fetal type posterior cerebral artery in half-T configuration for the treatment of a posterior communicating aneurysm using a transcirculation approach through the anterior communicating artery. This represents a useful and effective technique and should be considered when encountering the above-described situation.

Background: Following flow diverter placement, approximately 20% of intracranial aneurysms remain as residual aneurysms at 1 year. Device malapposition is a cause of residual aneurysms after flow diversion. We present a new and straightforward technique (exchange-free technique [EFT]) to enhance apposition of the surpass flow diverter (SFD), the only over-the-wire flow diverter currently available. Materials and Methods: We deployed laser-cut mini stents through the inner deployment catheter of the SFD. This maneuver was performed simply by withdrawing the micro-guidewire from its lumen and replacing it with a mini-stent (stents deliverable through microcatheters with inner diameter of 0.0165 inches), without a need to re-cross the deployed SFD or an exchange maneuver. All aneurysms in which this technique was utilized were retrospectively reviewed. Results: Twenty-eight patients (20 females) with 30 treated aneurysms were identified. The mean aneurysm diameter was 10.2 ± 6.6 mm. Technical success rate was 96.6% (29/30 aneurysms). There was no mortality or permanent morbidity related to the procedures. Except for the patient treated for an iatrogenic, surgery-related internal carotid artery pseudoaneurysm who died secondary to consequences of multiple surgeries, no cases of mortality or permanent morbidity were noted. Complete aneurysm occlusion rates were 78.2%, 82.1%, and 95.2% at 0–3, 3–6, and 9–12 months, respectively. None of the patients were re-treated. Conclusion: EFT is a simple and fast technique which was not associated with adverse effects in our series. The higher aneurysm obliteration rate obtained with EFT is probably the result of better wall apposition of the SFD.

Background Though flow diverter is a safe and efficient modality, some patients can experience delayed aneurysmal rupture. The mechanism of delayed rupture is still obscure to us. Methods We performed a systematic search in the PubMed database for patients with delayed rupture of intracranial aneurysms after flow diverter placement. Results A total of 36 articles reporting on 60 patients were included in the final analysis. Of the 49 patients with description of presenting symptoms, six (12.2%) patients were incidentally diagnosed, 39 (87.8%) patients were admitted for aneurysmal rupture or mass effect. Multiple flow diverters were used in 38.3% (18/47) of the patients. Coil assistance was applied in 13.0% (7/54) of the patients. Delayed aneurysmal rupture led to intracranial hemorrhage or carotid–cavernous sinus fistula (CCF) in 76.8% (43/56) and 23.2% (13/56) of the patients, respectively. Of the 55 patients with description of outcome, 14 (25.5%) patients achieved good recovery, one (1.8%) patient was severely disabled, 40 (72.7%) patients died. All of the patients in the CCF group survived and experienced good recovery. Conclusion Increased intra-aneurysmal pressure, destabilization of the aneurysm wall by intra-aneurysmal thrombus, persistent residual intra-aneurysmal flow, characteristics of the specific aneurysm, and mechanical injury by the flow diverter might conjointly contribute to the final delayed rupture. There has been no established preventive measure to decrease the incidence of delayed rupture yet. The treatment and outcome depend on the presentation of delayed rupture. Patients presenting with aneurysm-related intracranial hemorrhage have a dismal outcome. Those presenting with CCFs usually have a satisfactory recovery.

We report a case of an unruptured, symptomatic, large right cavernous internal carotid artery aneurysm successfully treated with a new balloon-expandable flow diverter – Xcalibur Aneurysm Occlusion Device (AOD). Follow up imaging performed at six months demonstrated complete exclusion of the aneurysm and regression in dimensions, resulting in resolution of mass effect and clinical improvement.

Flow diverters (FD) have poor radiopacity, challenging visualization of deployment and vessel wall apposition with conventional neuroimaging modalities. We evaluated a novel cone beam computed tomography (CT) imaging technique that allows virtual dilution (VD) of contrast media to facilitate workflow and ensure accurate assessment of FD wall apposition. We retrospectively evaluated all patients treated for intracranial aneurysms with FD at our institution between November 2018 and November 2019. Undiluted injected dual cone beam CT acquisitions performed post-stenting were displayed with VD software (GE Healthcare). The resulting images were compared with conventional two-dimensional (2D) digital subtraction angiography (DSA) images. Two neurointerventionalists (Reader 1 and Reader 2, (R1, R2)) independently assessed FD deployment and wall apposition. Confidence in the diagnosis, inter-reader agreement, and X-ray exposure were assessed. A total of 27 cases were reviewed. FD deployment and wall apposition scores were 4.2 ± 1.0 (R1) and 4.0 ± 1.1 (R2) for DSA and 3.7 ± 1.2 (R1) and 4.1 ± 1.0 (R2) for VD. Confidence in the diagnosis was improved with VD, with scores of 3.7 ± 0.7 (R1) and 4.0 ± 0.7 (R2) using DSA and 4.9 ± 0.2 (R1) and 4.9 ± 0.2 (R2) using VD (P

Objective p64MW HPC is a new low-profile flow diverter with reduced thrombogenicity due to hydrophilic coating. The purpose of this study was to evaluate its safety and efficacy in Mongolian patients under dual antiplatelet therapy. Methods Consecutive patients with unruptured anterior circulation aneurysms were prospectively enrolled. All patients received aspirin and clopidogrel before and six months after the procedure, followed by lifelong aspirin medication. High platelet reactivity (VerifyNow) did not trigger further action. The safety and efficacy endpoints were clinical outcome and aneurysm occlusion. Results In 29 patients (26 female, median age 57 years), 46 aneurysms (neck width 3.3 mm, fundus diameter 3.7 mm, median) were treated. Dual platelet function inhibition was confirmed in eight patients (28%). The response to Clopidogrel was between 100 and 239 P2Y12 reaction units (VerifyNow) in 13 patients (45%). Non-response to at least one drug was found in 8 of 29 patients (28%). One collapsed p64MW HPC required balloon angioplasty. No other periprocedural thrombus formation occurred. Postprocedural MRI revealed lesions with diffusion restriction in 3 of 29 patients. Digital subtraction angiography after three months for 42 of 46 (91%) aneurysms showed an adequate aneurysm occlusion in 25 (60%). Distal p64MW HPC migration of 3 implants was retreated with another p64MW HPC. Follow-up digital subtraction angiography of 26 of 46 (57%) aneurysms after six months showed adequate aneurysm occlusion in 22 (85%). Significant in-stent stenosis or thrombosis, morbidity or mortality was not encountered. Conclusion p64MW HPC implantation in patients under dual antiplatelet therapy with or without dual platelet function inhibition has a low procedural complication rate. The early aneurysm occlusion rate is high.

BackgroundIn the last decade, flow diverter (FD) devices are one of the widely used endovascular methods in the treatment of intracranial aneurysms. As the frequency of its use is increasing progressively, we thought that studies concerned with the use of FD at specific locations are helpful to clarify the efficacy and safety of FD as a treatment option in cerebral aneurysms. We represent our experiences in the treatment of posterior communicating artery (PCOM) aneurysms by FD devices aiming to assess its angiographic efficacy (complete aneurysm occlusion) and its related complications. This is a retrospective study of 47 patients harboring 47 PCOM aneurysms treated with Pipeline Embolization Device (PED). Acutely ruptured and non-saccular aneurysms were excluded from the study. Short- and mid-term radiological and clinical outcomes were analyzed.ResultsProcedure-related complications were observed in five patients (two ischemic events, two transient ischemic attacks (TIA), and one ipsilateral distal hemorrhage) with no procedure-related mortality. Complete aneurysm occlusion was encountered in 87.2%. In multivariable analysis, large-sized aneurysm and incorporated vessels were an independent predictor of non-occlusion (P= 0.026 andP= 0.035 respectively). A favorable clinical outcome (modified Rankin Scale, 0–2) was observed in 45/47 patients (95.7%); the incidence of postoperative complications was an independent predictor of unfavorable clinical outcomes (P= 0.048).ConclusionPED stent provides a high occlusion rate in the treatment of PCOM aneurysms with good post-treatment clinical outcomes.

BackgroundFlow diversion is a common endovascular treatment for cerebral aneurysms, but studies comparing different types of flow diverters are scarce.ObjectiveTo perform a propensity score matched cohort study comparing the Pipeline Embolization Device (PED) and Flow Redirection Intraluminal Device (FRED) for posterior circulation aneurysms.MethodsConsecutive 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.ResultsA 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).ConclusionComparative 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.

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.

BackgroundThe Pipeline Vantage Embolization Device with Shield Technology is a next generation flow diverter developed to improve aneurysm occlusion and implant endothelialization in addition to lowering thrombogenicity. We report here the in vivo biocompatibility and in vitro hemocompatibility performance of the Pipeline Vantage Embolization Device with Shield Technology (Vantage) compared with the Pipeline Flex Embolization Device (Flex).MethodsBiocompatibility (via histology), aneurysm occlusion and vessel patency (via angiography), and endothelial coverage (via scanning electron microscopy (SEM)) for the Vantage and Flex devices were assessed in the rabbit elastase aneurysm model at 90 days (n=29) and 180 days (n=27). In vitro thrombogenicity for Flex and Vantage (n=16) was assessed using a human blood flow loop model at low heparin concentration (0.6 U/mL) with thrombin generation, platelet activation and thrombus visualization as outputs.ResultsRaymond Roy Occlusion Classification grade 1 was higher for Vantage (61%) compared with Flex (46%), but was not statistically significant (p>0.05). All branch vessels were patent. Histological measures for both devices were similar (p>0.05). Endothelial coverage of the implant was significantly better for Vantage compared with Flex (p<0.05) for Vantage compared with Flex. High resolution microscopy showed less accumulation of thrombus on Vantage as compared with Flex.ConclusionVantage improved aneurysm occlusion and implant endothelialization and had significantly lower thrombogenicity as compared with Flex, while preserving the biocompatibility safety profile of Flex.

BackgroundThe first and second generations of the Pipeline Embolization Device (PED) have been widely adopted for the treatment of intracranial aneurysms (IAs) due to their high associated occlusion rates and low morbidity and mortality. The objective of this study was to evaluate the safety and effectiveness of the third- generation Pipeline Shield device (PED-Shield) for the treatment of IAs.MethodsThe SHIELD study was a prospective, single-arm, multicenter, post-market, observational study evaluating the PED-Shield device for the treatment of IAs. The primary efficacy endpoint was complete aneurysm occlusion without significant parent artery stenosis or retreatment at 1-year post-procedure and the primary safety endpoint was major stroke in the territory supplied by the treated artery or neurological death.ResultsOf 205 subjects who consented across 21 sites, 204 subjects with 204 target aneurysms were ultimately treated (mean age 54.8±12.81 years, 81.4% [166/204] female). Technical success (ie, deployment of the PED-Shield) was achieved in 98.0% (200/204) of subjects with a mean number of 1.1±0.34 devices per subject and a single device used in 86.8% (177/204) of subjects. The primary effectiveness endpoint was met in 71.7% (143/200) of subjects while the primary safety endpoint occurred in six (2.9%) subjects, two (1.0%) of which led to neurological death.ConclusionsThe findings of the SHIELD study support the safety and effectiveness of the PED-Shield for IA treatment, evidenced by high occlusion rates and low rates of neurological complications in the study population.Clinical trial registration-URLhttp://www.clinicaltrials.gov. Unique identifier: NCT02719522.

Purpose Despite a growing range of therapeutic possibilities, including various intravascular methods, treating cerebral aneurysms can be still a therapeutic challenge. A growing number of patients previously treated with older techniques require additional therapy. Treatment options as well as their efficiency may be influenced by previous procedures. Case report We report a rare case of a giant treatment-resistant aneurysm in a 65-year-old woman. The aneurysm was first diagnosed due to visual disturbances in the right eye. Computed tomography angiography showed large (20 × 18 mm) wide neck aneurysm of the right internal carotid artery. The patient was subsequently treated with several methods including coiling with regular stent implantation, two flow diverter stent implantations, and hybrid neurosurgery. Full occlusion was not achieved after any of those procedures. After the last procedure (hybrid neurosurgery) the patient, in vegetative state, was transferred to the intensive care unit and then to the Health and Care Centre. Conclusions Discussion focuses on endovascular treatment options after failure of previous treatment such as "stent in stent" technique. We conclude that three subsequent stent implantations are technically possible; however, subsequent procedures are associated with technical difficulties and their effectiveness is questionable. Ventriculoperitoneal shunt may influence the outcome of flow diversion therapy.

The implantation of flow diverters requires administration of dual anti-platelet therapy, posing the potential for complications. The p48MW HPC (phenox, Bochum, Germany) hydrophilic-coated flow diverting stent is designed to be anti-thrombotic, thus opening the potential for single anti-platelet therapy. We deploy a novel intravascular high-resolution imaging technique, high-frequency optical coherence tomography (HF-OCT), to study in an animal model the acute thrombus formation on coated p48MW devices versus uncoated control devices. Three pigs were implanted with 4 flow diverters each, two test hydrophilic-coated devices, and two control uncoated devices (p48MW). Each pig was treated with a different anti-platelet regime: no anti-platelet therapy, aspirin only, aspirin and clopidogrel. Twenty minutes after the flow diverter was implanted, an HF-OCT data set was acquired. Acute clot formed on the flow diverter at each covered side branch was measured from the HF-OCT slices. Factors considered to be important were the device type (pHPC versus bare metal), aspirin, clopidogrel, and vessel location. A linear model was constructed from the significant factors. Both coating (p

BackgroundFlow diverting stent (FDS) devices have revolutionized the treatment of large and complex brain aneurysms, but there is still room for improvement, particularly on the flow diversion properties and technical challenges associated with stent deployment. In this study we compared flow diversion properties between the new generation Surpass Evolve (Stryker) and the Pipeline Flex (Medtronic) devices by quantitatively evaluating intra-aneurysmal flow modification.MethodsAn in vitro experimental set-up was used, consisting of four patient-specific silicone models with internal carotid aneurysms and a circulating hemodynamic simulation system with pulsatile flow. The Evolve and Pipeline stents were deployed across the neck of each aneurysm model, in a randomized fashion, for a total of eight device deployments. A 60 frames/s digital subtraction angiography run was acquired before and after placement of each FDS. An optical flow-analysis method was used to measure intra-aneurysmal flow modification induced by the stent by calculating a mean aneurysm flow amplitude (MAFA) before and after stent placement and computing a ratio.ResultsAverage MAFA ratio values calculated from pre- and post-stent placement were significantly lower after deployment of the Evolve (n=4, mean=0.62±0.09) compared with the Pipeline device (n=4, mean=0.71±0.06) (p=0.03).ConclusionsOur in vitro results show that the Evolve stent had a superior flow diversion effect compared with the Pipeline stent, which—based on clinical evidence—suggest it may promote faster aneurysm occlusion rates in patients.

The management of residual or persistent intracranial aneurysms after flow-diversion therapy is not well defined in the literature. In this multicentric study, we report clinical and angiographic outcomes of 11 patients that underwent retreatment for 12 aneurysms initially treated with flow-diverter stents. The median patient age was 53 years. Aneurysms (median size, 7.3 mm) were located at the internal carotid artery in 9 cases, and at the posterior circulation in 3. Treatment strategies, complications, and angiographic outcome were retrospectively assessed. Retreatment was feasible in all cases and performed by overlapping flow-diverter implantation. Overall, 12 side vessels were covered during retreatment, whereof 10 (83.3%) remained patent until mid-term follow-up. There were no further technical or symptomatic complications and no treatment-related morbidity. Angiographic follow-up (median, 17 months) showed improved aneurysm occlusion in all patients. Complete or near-complete aneurysm occlusion was achieved in 11 aneurysms (91.7%). Required retreatment after failed flow-diversion therapy can be performed with adequate safety and efficacy by placement of additional flow-diverter stents.

Introduction: Despite numerous advances in the endovascular treatment of intracranial aneurysms (IAs), treatment in cases of wide-neck, complex configurations or branching locations remains challen...