Flow diversion beyond the circle of Willis: endovascular aneurysm treatment in peripheral cerebral arteries employing a novel low-profile flow diverting stent

Robotically assisted deployment of flow diverter stents for the treatment of cerebral and cervical aneurysms

BACKGROUND

Despite the growing sophistication of robot-assisted surgery, it is necessary to demonstrate that robots can reliably perform complex procedures on site and then remotely. Although a flow diverter stent is one of the most effective and widely used devices, its placement is sometimes challenging.

OBJECTIVE

To evaluate the feasibility and safety of the CorPath GRX robotic platform for the embolization of cerebral and cervical aneurysms using flow diverter stents.

METHODS

We performed a single-center technical study of the first 10 flow diverter stent deployments with the CorPath GRX Robotic System (Corindus Inc, Waltham, Massachusetts, USA) for the treatment of cerebral aneurysms between April and October 2022.

RESULTS

Ten patients underwent robot-assisted embolization with flow diverter stents: there were nine intracranial aneurysms (paraclinoid n=6; posterior communicating artery aneurysm n=1; anterior communicating artery n=2) and one cervical aneurysm. Four procedures were performed with coils plus a flow diverter stent, one was performed with woven endobridge plus a flow diverter stent and four were performed with flow diverter stents alone. Of these procedures, two were performed with telescoping flow diverters.All flow diverter stents were deployed with robotic assistance, with only one partial conversion to a manual technique (caused by guidewire torquability limitations). No perioperative complications were observed.

CONCLUSION

Robot-assisted flow diverter stent deployment using the CorPath GRX platform is feasible and appears to be safe. Larger, in-depth studies of the technique's safety and benefits are now warranted.

Clinical and angiographic characteristics of ruptured and unruptured distal cerebral aneurysms: a review of a large series of cases in a high-volume center

OBJECTIVE

To evaluate clinical, angiographic features, and endovascular approach of ruptured and unruptured distal intracranial aneurysms (DIAs).

METHODS

From January 2013 to February 2022, details of all consecutive intracranial aneurysms (IAs) treated endovascularly in our center were collected and retrospectively reviewed. IAs involving the anterior cerebral artery, middle cerebral artery, and posterior cerebral artery (distal to anterior communicating artery, limen insula, and P1 segment, respectively), and those distal to superior cerebellar artery, anterior-inferior cerebellar artery, and posterior inferior cerebellar artery's first segment were classified based on their etiology, location, size, and shape. Demographic, clinical, angiographic, and procedural variables, as well as follow-up outcomes were evaluated.

RESULTS

Of 2542 IAs, 151 (5.9%) DIAs were counted (average size 5.4±2.9 mm), including 61 (40.4%) unruptured and 90 (59.6%) ruptured. No difference in the aneurysmal size was observed, but aneurysms smaller than 4 mm were observed more frequently in the ruptured group (36.7% vs 18%; P=0.01). In addition, ruptured DIAs were more often non-saccular (40% vs 18%; P=0.004) and irregular (93.3% vs 59%; P<0.001), They were treated mostly by coiling, glue, and parent artery sacrifice (P=0.02, P=0.006, and P=0.001), whereas unruptured DIAs were treated by stent-assisted coiling and flow-diverter stents (P=0.001 and P<0.001, respectively), without any differences in occlusion (81.6% vs 82.5%) and recanalization (21.1% vs 17.5%) rates. Procedure-related complications occurred in 20/151 (13.2%) patients, without any differences between subgroups. Ruptured DIAs were more often re-treated (18.4% vs 5.3%, P=0.02). In multivariate analyses, irregular shape appeared as an independent predictor of ruptured presentation (OR=8.1, 95% CI 3.0 to 21.7; P<0.001).

CONCLUSIONS

Compared with unruptured DIAs, ruptured DIAs were more often non-saccular, irregular, and smaller than 4 mm. Despite different therapeutical approaches, ruptured and unruptured DIAs presented comparable occlusion and recanalization rates.

Patient outcomes after treatment of brain aneurysm in small diameter vessels with the silk vista baby flow diverter: A systematic review

BACKGROUND

The Silk Vista Baby (SVB, BALT) is a first-in-class flow-diverter device delivered using a 0.017" microcatheter, designed for the treatment of intracranial aneurysms, including those in small diameter vessels. This study reports a systematic literature review (SLR) to evaluate the safety and efficacy of using SVB to treat intracranial aneurysms in vessels less than 3.5 mm in diameter.

METHODS

We performed a PRISMA-compliant SLR to evaluate the outcomes of SVB in the treatment of aneurysms in small intracranial vessels. Primary outcomes were occlusion status and major stroke, and secondary outcomes included all-cause mortality, procedure-related neurologic death, and post-operative aneurysm rupture. Data were expressed as descriptive statistics only.

RESULTS

A total of four studies, including 163 patients with 173 intracranial aneurysms, were included. The most common aneurysm locations were the anterior cerebral artery (24.9% [43/173]), the middle cerebral artery (24.3% [42/173]), and the anterior communicating artery (23.1% [40/173]). Parent artery diameter ranged from 0.9 mm to 3.6 mm, and 29% were acutely or previously ruptured aneurysms. Overall, complete or near-complete occlusion was 72.1% on early-term follow-up. Mortality rate among the studies was 2.5%, with 3 instances adjudicated as neurologic deaths (1.8%). Major stroke was noted in 1.2% of cases, and branch occlusion or stent thrombus formation in 5.5%.

CONCLUSION

Our review suggests that SVB is a safe and effective treatment for intracranial aneurysms in small vessels. Further prospective and comparative studies with patient outcome data specific to aneurysm location are needed to confirm the safety and efficacy of SVB.

Delayed Foreshortening and Prolapse of Silk Vista Baby into Superior Cerebellar Artery Aneurysm

BACKGROUND

Flow diversion has evolved as a minimally invasive treatment for intracranial aneurysms. The Silk Vista Baby (SVB) can be navigated into small cerebral vessels because it can be deployed through a low-profile microcatheter.

METHODS

We report on treating a patient in his 70s with an unruptured fusiform right superior cerebellar artery aneurysm using an SVB.

RESULTS

Significant foreshortening of the device was noted during the initial procedure; however, the position was satisfactory with good apposition and clearance of the aneurysm neck. A stable position of the SVB on 1-day and 2-month postprocedural computed tomography angiography was also demonstrated. Subsequently, a 6-month follow-up computed tomography angiography detected delayed foreshortening and prolapse of the SVB into the aneurysm, for which an additional SVB was placed in a second procedure. There were no complications and the patient remained clinically well.

CONCLUSIONS

Although the intraoperative foreshortening was not unexpected, the delayed postprocedural behavior of proximal foreshortening and subsequent prolapse of the SVB into the aneurysm have not been previously described. We would like to share this for awareness in this technical note.

Flow-diverter stents in intracranial aneurysm treatment: impact on covered cerebral artery branches

OBJECTIVE

Flow diverter stents (FDSs) have attracted interest for intracranial aneurysm (IA) treatment; however, occlusion of side branches and related complications have been reported. This study aimed to investigate the effects of FDSs in IA management when different branches of intracranial arteries are covered.

MATERIALS AND METHODS

A cross-sectional study was conducted using PUBMED, Embase, Web of Science, and Cochrane databases to include randomized or nonrandomized comparative-designed studies from January 2000 to August 2022 which reported outcomes of occlusion/narrowing of branches after IA treatment using FDSs. The PRISMA guidelines were used for our report. A random-effects meta-analysis was conducted to pool the outcomes, which included incidence rates of occlusion/narrowing of FDS-covered branches, branch occlusion-related symptoms, obliteration of IAs, and ideal clinical outcomes (modified Rankin Scale score ≤2).

RESULTS

The authors identified 57 studies involving 3789 patients with IA managed by FDSs covering different branches. During the median imaging follow-up at 12 months, the IA obliteration rate was satisfactory (>70%) when covering the ophthalmic artery (OA), posterior communicating artery (PComA), anterior choroidal artery (AChoA) or anterior cerebral artery (ACA), but not the middle cerebral artery-M2 segment (MCA-M2; 69.5%; 95% CI: 60.8-77.5%) and posterior inferior cerebellar artery (PICA; 59.1%, 13/22). The overall ideal clinical outcome was observed in 97.4% of patients (95% CI: 95.5-98.9%). Higher rates of occlusion/narrowing of branches were identified when FDSs covered the ACA (66.6%; 95% CI: 45.1-85.3%), PComA (44.3%; 95% CI: 34.2-54.6%), or MCA-M2 (39.2%; 95% CI: 24.5-54.7%); the risks were lower when covering the OA (11.8%; 95% CI: 8.8-15.1%), PICA (6.8%; 95% CI: 1.5-14.5%), and AchoA (0.5%; 95% CI: 0.0-2.9%). The risk of branch occlusion-related complications was low (incidence rate <5%) for each of the six evaluated branches.

CONCLUSIONS

Acceptable outcomes were identified following treatment of IAs when FDSs were placed across each of the six studied cerebral arteries. Treatment decisions regarding FDS placement across branch arteries should be made with the risk of complications from branch occlusion in mind.

Trends in Ruptured and Unruptured Aneurysmal Treatment from 2010 to 2020: A Focus on Flow Diversion

OBJECTIVE

Flow diverters are a promising new tool in the neurosurgeon's arsenal for aneurysm management. We sought to quantify the trends of flow diversion in comparison to traditional endovascular coiling and surgical clip ligation techniques in the United States from 2010 to 2020 with an emphasis on aneurysm location and preferences in usage for ruptured versus unruptured aneurysms.

METHODS

In this large cross-sectional study, patients aged 18 and older within the MARINER database were analyzed. Descriptive characteristics were calculated for all included patients. χ2 tests were used to compare categorical variables. P values < 0.05 were statistically significant.

RESULTS

A total of 45,542 procedures were conducted in the United States from 2010 to 2020 (clipping: 14,491; coiling: 28,840; flow diversion: 2211). The Southern United States had the largest operative volume across all 3 intervention types, closely followed by the Midwest. Aneurysms of the middle cerebral artery were mostly clipped, whereas coiling and flow diversion techniques were most utilized for anterior communicating and posterior communicating artery aneurysms. Flow diversion is growing most rapidly in the treatment of unruptured aneurysms, though there were also significant increases in usage for ruptured aneurysm treatment from 2019 to 2020.

CONCLUSIONS

Flow diverters have gained significant traction in the treatment for both unruptured and ruptured aneurysms. In the coming years, the indications and use of flow diversion will undoubtedly grow further, but excitement over their application should be tempered by the safety and efficacy data that continues to emerge.

The application of high-resolution vessel wall imaging in the in situ bypass surgeries for complex anterior cerebral artery aneurysms

OBJECTIVE

Complex anterior cerebral artery (ACA) aneurysms are still technically challenging to treat. Bypass surgery is needed to achieve aneurysm obliteration and ACA territory revascularization. Severe atherosclerosis of aneurysm walls can cause clip slippage, intraoperative rupture, postoperative ischemic events. How to assess the atherosclerotic changes in vascular walls by high-resolution vessel wall magnitude resonance imaging (VWI) is the key question in complex ACA aneurysm surgical management.

METHODS

This retrospective single-center study included eight patients diagnosed with complex anterior cerebral arteries admitted to our hospital for bypass surgery from January 2019 to April 2022. We discussed the application of VWI in aneurysms treated with in situ bypass and reviewed previous experience of revascularization strategies for complex ACA aneurysms.

RESULTS

In this study, we treated 8 cases of complex ACA aneurysms (3 communicating aneurysms/5 postcommunicating aneurysms) over the prior one year. In situ side-to-side anastomosis (1 A2-to-A2/6 A3-to-A3) was performed in seven cases, and trapping combined with excision was performed in another case. Following bypass, complete trapping was performed in 4 cases, and proximal clipping was performed in 3 cases. No surgery-related neurological dysfunctions were observed. The final modified Rankin scale was 0 in seven of the eight cases and 2 in one case.

CONCLUSION

High-resolution VWI, as a favorable preoperative assessment tool, provides insight into patient-specific anatomy and microsurgical options before operations, which can help neurosurgeons develop individualized and valuable surgical plans.

Distal Flow Diversion with Anti-Thrombotically Coated and Bare Metal Low-Profile Flow Diverters—A Comparison

Background and purpose: The establishment of low-profile flow diverting stents (FDS), for example, the Silk Vista Baby (SVB) and the p48MW, facilitated endovascular treatment of peripheral cerebral aneurysms. This study therefore aims to compare the performance and outcomes of the SVB with those of the p48MW HPC, with a special focus on hemodynamic aspects of peripheral segments and bifurcations. Materials and methods: The study cohort comprises 108 patients, who were either treated with the SVB or the p48MW HPC between June 2018 and April 2021. Results: Sixty patients received a SVB and forty-eight patients a p48MW HPC. The SVB was used predominantly in the AcomA-complex, and the p48MW HPC in the MCA bifurcation. Immediately after implantation, significant hemodynamic downgrading (OKM A2-A3, B1-B3, C3) was achieved in 60% in the SVB group vs. 75.1% in the p48MW HPC group. At the second follow-up, after an average of 8.8 and 10.9 months, respectively, OKM D1 was observed in 64.4% of the SVB group vs. 27.3% in the p48MW HPC group. Only 1.7% vs. 6.8% of the aneurysms remained morphologically unaltered (OKM A1). Adverse events with persisting neurologic sequalae at last follow-up were largely comparable in both groups (5.0% vs. 4.2%). Conclusion: Immediately after implantation, the p48MW HPC had a more profound hemodynamic impact than the SVB; however, early complete occlusions were achieved in a greater proportion of lesions after implantation of the uncoated SVB.

Endovascular treatment of challenging aneurysms with FRED Jr flow diverter stents: a single-center experience

PURPOSE

To analyze clinical safety and efficacy of flow re-direction endoluminal device (FRED) Jr flow diverter for treatment of unruptured, ruptured, or recanalyzed aneurysms.

MATERIALS AND METHODS

Between October 2019 and February 2022, 25 patients with 31 aneurysms treated with FRED Jr were included in the study. Clinical and radiological records, procedural details, and follow-up outcomes were retrospectively evaluated. Eighteen (72%) patients were female. Median age was 48.8 (age range 9-85). Mean follow-up was 21 months (6-28 months). Location of the aneurysms were as follows; 13 in middle cerebral artery (MCA), 7 in anterior cerebral artery (ACA), 4 in posterior cerebral artery (PCA), 3 in true posterior communicating artery (PCom), 2 in anterior communicating artery (ACom), 1 in superior cerebellar artery (SCA), 1 in true ophthalmic artery. Five patients (20%) presented with acute subarachnoid hemorrhage (aSAH).

RESULTS

In all procedures, FRED Jr was successfully deployed. Three true Pcom aneurysms and a true ophthalmic aneurysm were treated with FRED Jr. Three patients with two adjacent aneurysms were treated with a single FRED Jr. In two (8%) patients in-stent thrombosis occurred intraoperatively, they were treated with iv tirofiban and thrombectomy without any sequelae. Post-discharge 2 weeks later, intraparenchymal hemorrhage occurred in a patient. He was treated with surgical drainage, the clinical course was modified Rankin score (mRS) 2. Digital subtraction angiography (DSA) was performed on 16 (64%) patients with 21 (67%) aneurysms. Near complete-complete occlusion (O'Kelly-Morata grading scale (OKM C-D) was documented in 15/16 (93.7%) patients, 20/21 (95.2%) aneurysms. In nine (36%) patients, no residual filling was observed in the magnetic resonance angiography (MRA). Good clinical outcome (mRS 0-1) was achieved in 24/25 (96%) of patients.

CONCLUSION

Endovascular treatment of small cerebral aneurysms with FRED Jr is safe and effective even in complex and challenging morphologies allowing high rates of aneurysm occlusion with low periprocedural complications. Our cohort, consisting of a rate 20% acute ruptured aneurysms, is the major additive data to the published literature.

Flow Diverter Devices in the Treatment of Anterior Communicating Artery Region Aneurysms: Would the Regional Anatomy and the Aneurysm Location Affect the Outcomes?

BACKGROUND

In this study, the authors evaluated the efficacy and the safety of flow diverter devices (FDD) in anterior communicating artery (ACoA) region aneurysms, focusing on anatomical factors that could affect the outcome, such as the location of the aneurysm along the ACoA (centered on ACoA or decentered on the A1-A2 junction) and the anatomy of the ACoA region.

METHODS

Clinical, procedural and follow-up data were analyzed. Aneurysms were classified according to the location along the ACoA (centered or decentered on the A1-A2 junction) and on the basis of the anatomical configuration of the ACoA region. Safety was assessed by recording intraprocedural, periprocedural and delayed complications to determine the morbidity and mortality rates. The functional outcome was evaluated with the modified Rankin scale (mRS) prior to and after the endovascular procedure. To assess the efficacy, midterm and long-term clinical, angiographic and cross-sectional imaging follow-ups were recorded. Subgroup analysis according to the different ACoA regional anatomical configurations and the ACoA aneurysm locations were performed.

RESULTS

33 patients (17 males; 16 females) with ACoA region aneurysms were treated with FDDs. 27 aneurysms were located at the A1-A2 junction (82%) while the remaining six aneurysms were centered on the ACoA. No mortality was recorded. The overall morbidity rate was 6% (2/33 procedures). Major complications occurred in 33% (2/6) of ACoA aneurysms and in the 0% of A1-A2 junction aneurysms. Mid-term and long-term neuroimaging follow-ups showed the occlusion of the aneurysm in 28/33 cases (85%). Complete occlusion rates were 93% in the A1-A2 junction aneurysms and 50% in ACoA aneurysms.

CONCLUSIONS

The FDD is a safe and effective tool that can be used in the treatment of selected cases of ACoA region aneurysms. The location of the aneurysm along the ACoA and the regional anatomy of the ACoA complex could affect the efficacy and safety.

A novel intracranial exchange guidewire improves the navigation of various endovascular devices: An in vitro study of challenging situations

OBJECTIVE

Neuroendovascular procedures rely on successful navigation and stable access to the target vessel. The Stabilizer is a 300 cm long exchange wire with a 0.014 diameter and a soft, flexible stent at the distal end designed to assist with navigation and device delivery. This study aims to assess the efficacy of the Stabilizer for navigation in a variety of challenging environments.

METHODS

The efficacy of the Stabilizer was evaluated using three challenging vascular models: a giant aneurysm model, a severe tortuosity model, and an M1 stenosis model. The Stabilizer was compared with a conventional wire during navigation in each model.

RESULTS

In the giant aneurysm model, there was no significant difference of success during straightening of a looped wire and significantly higher success rates when advancing an intermediate catheter with the Stabilizer beyond the aneurysm neck compared to a conventional guidewire. The Stabilizer also significantly increased success rates when advancing an intermediate catheter through a model with severe tortuosity compared to a conventional guidewire, as well as exchange maneuver for intracranial stenting in a stenosis model compared to an exchange wire.

CONCLUSIONS

In our experimental model, the Stabilizer significantly improved navigation and device delivery in a variety of challenging settings compared to conventional wires.

Silk Vista Baby for the Treatment of Complex Posterior Inferior Cerebellar Artery Aneurysms

BACKGROUND

Treatment of small-caliber vessel lesions using flow diverters remains challenging because of vasculature's narrow luminal diameter and tortuosity. This in turn makes navigation and delivery of conventional devices with standard microcatheters more difficult. The Silk Vista Baby (SVB, Balt) flow diversion device was designed for ease of use in vessels with a smaller diameter, distal lesions, and 0.017 ″ microcatheter delivery systems.

OBJECTIVE

To report the outcomes of the SVB device on the treatment of posterior inferior cerebellar artery (PICA) aneurysms.

METHODS

Databases from different centers were retrospectively reviewed for PICA aneurysms treated with SVB. Demographic information, clinical presentation, radiographic characteristics, procedural complications, and immediate postprocedure outcomes were obtained.

RESULTS

Fourteen patients harboring 15 true PICA aneurysms were treated between January 2019 and June 2021. Nine were female (n = 9/14; 64.2%), and the mean age was 51 ± 14.9 years. Most patients had previously ruptured aneurysms, treated by another endovascular technique. Six aneurysms were located distally (n = 6/15; 40%). The mean neck size was 3 mm (SD 1.35, range 2.5-5 mm), whereas the mean PICA diameter was 1.6 mm (SD 0.26, range 1.5-1.7 mm). The mean length of follow-up was 6 months (SD 8.28, range 4.5-16 months). Treatment-related adverse events included 1 case of transient hypoesthesia. Two additional events were reported, but adjudicated as unrelated to the procedure. Complete occlusion, measured as Raymond-Roy class I, was achieved in all cases.

CONCLUSION

The SVB device was safely and effectively used in the treatment of PICA aneurysms. The smaller delivery system profile reduces the risk of procedure complications and creates new treatment options for distal lesions.

Pipeline embolization of proximal middle cerebral artery aneurysms: A multicenter cohort study

BACKGROUND AND PURPOSE

Flow diversion of aneurysms located in the M1 segment and middle cerebral artery bifurcation with Pipeline embolization device is sometimes performed, but further study is needed to support its regular use in aneurysm treatment. Here, we report measures of safety and efficacy for Pipeline embolization in the proximal middle cerebral artery in a multi-center cohort.

MATERIALS AND METHODS

Clinical and angiographic data of eligible patients were retrospectively obtained from participating centers and assessed for key clinical and angiographic outcomes. Additional details were extracted for patients with complications.

RESULTS

In our multi-center cohort, complete aneurysm occlusion was achieved in 71% (17/24) of treated aneurysms. There were no deaths or disabling strokes, but non-disabling ischemic strokes occurred in 8% (2/24) of patients. For aneurysms in the M1 segment, complete aneurysm occlusion was observed in 75% (12/16) of aneurysms, aneurysm volume reduction was observed in 100% (16/16) of aneurysms, and non-disabling ischemic strokes occurred in 13% (2/16) of patients. For aneurysms at the middle cerebral artery bifurcation, complete aneurysm occlusion was observed in 63% (5/8) of aneurysms, aneurysm volume reduction occurred in 88% (7/8) of aneurysms, and ischemic or hemorrhagic complications occurred in 0% (0/8) of patients.

CONCLUSION

Pipeline embolization of cerebral aneurysms in the M1 segment and middle cerebral artery bifurcation demonstrated a 71% rate of complete aneurysm occlusion. There were no deaths or disabling strokes, but there was an 8% rate of non-disabling ischemic strokes.

Indirect Flow Diversion for Off-Centered Bifurcation Aneurysms and Distant Small-Vessel Aneurysms, a Retrospective Proof of Concept Study From Five Neurovascular Centers

Background: Treatment of cerebral aneurysms using hemodynamic implants such as endosaccular flow disruptors and endoluminal flow diverters has gained significant momentum during recent years. The intended target zone of those devices is the immediate interface between aneurysm and parent vessel. The therapeutic success is based on the reduction of aneurysmal perfusion and the subsequent formation of a neointima along the surface of the implant. However, a subset of aneurysms-off-centered bifurcation aneurysms involving the origin of efferent branches and aneurysms arising from peripheral segments of small cerebral vessels-oftentimes cannot be treated via coiling or implanting a hemodynamic implant at the neck level for technical reasons. In those cases, indirect flow diversion-a flow diverter deployed in the main artery proximal to the parent vessel of the aneurysm-can be a viable treatment strategy, but clinical evidence is lacking in this regard. Materials and Methods: Five neurovascular centers contributed to this retrospective analysis of patients who were treated with indirect flow diversion. Clinical data, aneurysm characteristics, anti-platelet medication, and follow-up results, including procedural and post-procedural complications, were recorded. Results: Seventeen patients (mean age: 60.5 years, range: 35-77 years) with 17 target aneurysms (vertebrobasilar: n = 9) were treated with indirect flow diversion. The average distance between the flow-diverting stent and the aneurysm was 1.65 mm (range: 0.4-2.4 mm). In 15/17 patients (88.2%), perfusion of the aneurysm was reduced immediately after implantation. Follow-ups were available for 12 cases. Delayed opacification (OKM A3: 11.8%), reduction in size (OKM B1-3: 29.4%) and occlusion (D1: 47.1%) were observable at the latest investigation. Clinically relevant procedural complications and adverse events in the early phase and in the late subacute phase were not observed in any case. Conclusion: Our preliminary data suggest that indirect flow diversion is a safe, feasible, and effective approach to off-centered bifurcation aneurysms and distant small-vessel aneurysms. However, validation with larger studies, including long-term outcomes and optimized imaging, is warranted.

Flow diversion for aneurysms beyond the circle of Willis: A preliminary experience

OBJECTIVE

To evaluate the safety and efficacy of flow diversion (FDs) for the aneurysms beyond the circle of Willis.

METHODS AND MATERIALS

We retrospectively reviewed the prospectively maintained database in our center and enrolled patients with aneurysms beyond the circle of Willis (defined as at or distal to the M1, A2, and P2 segments) that were treated with FDs.

RESULTS

Between July 2017 to December 2020, 28 patients with 28 aneurysms met the inclusion criteria and were included in this study, with a median age of 50 years old (IQR, 36-63 years). Thirty FDs, including 5 Pipelines and 25 Tubridge FDs, were deployed. Perioperative complications were noticed in 2 patients (7.1%), while asymptomatic adverse events occurred in another three patients (10.7%). Delayed complications occurred in 3.6% of patients (1/28). All patients received clinical follow-up, with the mortality and long-term morbidity of 0 and 3.6% (1/28), respectively. Angiographic follow-up data were available for 26 patients (92.9%) with an interval of 10 ± 7 months (ranged 2-26 months). Sixteen patients (61.5%) showed complete or nearly complete occlusion of aneurysms (OKM grading scale D and C); 6 cases (23.1%) were revealed incomplete occlusion (OKM grading scale B), and 4 cases (15.4%) remained unchanged (OKM grading scale A). The existence of the perforators derived from aneurysms was associated with a lower occlusion rate (p = 0.032).

CONCLUSION

Flow diversion is reliable in the treatment of distal aneurysms with a high technical success rate and low permanent disability rate. The presence of side branches derived from aneurysms was associated with a lower aneurysm occlusion rate.

Contemporary Management of Distal Anterior Cerebral Artery Aneurysms: A Dual-Trained Neurosurgeon's Perspective

Objectives  Distal anterior cerebral artery (DACA) aneurysms are a subset of aneurysms located in the anterior circulation but away from the circle of Willis. We analyze the clinical presentation and outcomes of two treatment groups-surgical and endovascular-for DACA aneurysms managed by a dual-trained neurosurgeon. Material and Methods  A retrospective evaluation of radiological and operative/interventional data of 34 patients with 35 DACA aneurysms over a 12-year period was analyzed. Twenty-seven patients underwent surgery, whereas seven underwent endovascular coiling of the aneurysms. Modified Fisher grade and World Federation of Neurosurgical Societies scale (WFNS) were used to note the subarachnoid hemorrhage (SAH) severity. Statistical Analysis  Categorical data were presented as frequency and percentage, while noncategorical data were represented as mean ± SD. Statistical significance for difference in outcome between the two groups was analyzed using Chi-square test, and p  < 0.05 was considered statistically significant. Results  Of 34 patients, 33 presented with a bleed and 23.5% patients were noted to have another aneurysm in addition to the DACA aneurysm. Patients who underwent clipping for another aneurysm along with the DACA aneurysm in a single surgical exercise had a poor outcome compared with those who underwent surgery for the lone DACA aneurysm (7 vs. 20, p  = 0.015). Most patients in both surgical (70.37%) and endovascular (85.71%) groups had good outcome (mRS ≤ 2). Conclusions  A good outcome can be achieved with either surgery or endovascular coiling in the management of DACA aneurysms. In patients with multiple aneurysms, SAH with aneurysmal rupture of DACA should be managed first; the other unruptured aneurysm may be operated after an interval to avoid morbidity.

Longitudinal Cost Profiles of Pipeline Embolization Device Versus Stent-Assisted Coiling in Propensity-Matched Unruptured Small Anterior Circulation Aneurysms

BACKGROUND

The cost profiles of stent-assisted coiling (SAC) vs Pipeline embolization device (PED) in small unruptured anterior circulation aneurysms have not been studied.

OBJECTIVE

To compare the 2 modalities cost profiles in a propensity-matched cohort controlling for potential technical complexity confounders including size and location.

METHODS

Patients treated with either SAC or PED at our institution were identified. Following propensity-score algorithm, 46 patients, 23 in each group were matched. The procedural and follow-up costs in each group were analyzed and compared.

RESULTS

Median maximal aneurysm size in the SAC and PED cohort were 5.3 vs 5.1 mm, respectively. Costs of access guide materials were significantly higher in the SAC group (P < .01). The average implant cost was not significantly different between the SAC and PED cohorts (${\$}$13973.2 ± ${\$}$2886.2 vs ${\$}$14,760.7 ± ${\$}$3782.1, respectively; P = .43). Similarly, total procedural costs were not different (${\$}$18341.5 ± 4104 vs ${\$}$17484.3 ± 2914.1, respectively, P = .42). Although there were significantly more total follow-ups (P = .02) and longer follow-up duration (P = .01) in SAC cohort, no significant difference in follow-up costs between the 2 groups was identified (${\$}$20557 ± ${\$}$9247 vs ${\$}$18958 ± ${\$}$9171.9, P = .56). Overall cost was similar between the SAC (${\$}$38898.9 ± ${\$}$9645.5) and PED groups (${\$}$36442.4 ± ${\$}$9076) (P = .38).

CONCLUSION

In small unruptured anterior circulation aneurysms (excluding anterior communicating artery aneurysms) matched for technical complexity confounders, SAC and PED offer an overall equivalent economic cost profile. Postprocedural noninvasive imaging was more frequent in the SAC group. However, follow-up costs and total costs were not significantly different.

Endovascular Management of Distal Anterior Cerebral Artery Aneurysms: A Multicenter Retrospective Review

INTRODUCTION

Distal anterior cerebral artery aneurysms (DACAA) are a rare and difficult entity to manage. Endovascular treatment has evolved for safe and durable treatment of these lesions. The objective of this study is to report the safety, efficacy, and outcomes of endovascular treatment of DACAA.

METHODS

A retrospective review of DACAA endovascularly treated at 5 different institutions was performed. Data included demographics, rupture status, radiographic features, endovascular technique, complication rates, and long-term angiographic and clinical outcomes. A primary endpoint was a good clinical outcome (modified Rankin scale 0-2). Secondary endpoints included complications and radiographic occlusion at follow-up.

RESULTS

A total of 84 patients were reviewed. The mean age was 56, and 64 (71.4%) were female. Fifty-two (61.9%) aneurysms were ruptured. A good functional outcome was achieved in 59 patients (85.5%). Sixty (71.4%) aneurysms were treated with primary coiling, and the remaining 24 were treated with flow diversion. Adequate occlusion was achieved in 41 (95.3%) aneurysms treated with coiling, and 17 (89.5%) with flow diversion. There were total 11 (13%) complications. In the flow diversion category, there were 2, both related to femoral access. In the coiling category, there were 9: 5 thromboembolic, 3 ruptures, and 1 related to femoral access.

CONCLUSION

Endovascular treatment, and in particular, flow diversion for DACAA, is safe, feasible, and associated with good long-term angiographic and clinical outcomes.

Intracranial Fusiform and Circumferential Aneurysms of the Main Trunk: Therapeutic Dilemmas and Prospects

Intracranial fusiform and circumferential aneurysms (IFCAs), especially those located on the main trunk, are uncommon and difficult to manage. Currently, literature focused on IFCAs on the main trunk of cerebral arteries is lacking. The treatment of IFCAs is still under debate. Therefore, in this review, we further explore the treatment of this complicated entity. In addition, we also present some interesting cases. Based on the literature review and our experience, we found that IFCAs are often located in the vertebrobasilar system and that ruptured or large symptomatic IFCAs are associated with increased mortality and higher rebleeding rates. The treatment strategies for IFCAs can be classified as deconstructive and reconstructive methods via open surgery and/or endovascular treatment (EVT). Currently, EVT is a popular method and the main therapeutic choice. In particular, flow diversion has revolutionized the treatment of IFCAs. Parent artery occlusion (PAO) with or without revascularization may still be considered a suitable choice. Complex IFCAs that cannot be resolved by EVT can also be treated via open surgery with or without extracranial–intracranial bypass. Targeted embolization for the weak points of IFCAs is a temporary or palliative choice that is rarely used. In summary, despite complications, both surgical treatment and EVT are effective options for appropriately selected cases. Due to the development of endovascular implants, EVT will have better prospects in the future.

Flow Diversion for Reconstruction of Intradural Vertebral Artery Dissecting Aneurysms Causing Subarachnoid Hemorrhage-A Retrospective Study From Four Neurovascular Centers

Objective: Dissecting aneurysms (DAs) of the vertebrobasilar territory manifesting with subarachnoid hemorrhage (SAH) are associated with significant morbi-mortality, especially in the case of re-hemorrhage. Sufficient reconstruction of the affected vessel is paramount, in particular, if a dominant vertebral artery (VA) is impacted. Reconstructive options include stent-assisted coiling and flow diversion (FD). The latter is technically less challenging and does not require catheterization of the fragile aneurysm. Our study aims to report a multicentric experience with FD for reconstruction of DA in acute SAH.

Materials and Methods: This retrospective study investigated 31 patients (age: 30–78 years, mean 55.5 years) who had suffered from SAH due to a DA of the dominant VA. The patients were treated between 2010 and 2020 in one of the following German neurovascular centers: University Hospital Leipzig, Katharinenhospital Stuttgart, BG Hospital Bergmannstrost Halle/Saale, and Heinrich-Braun-Klinikum Zwickau. Clinical history, imaging, implanted devices, and outcomes were reviewed for the study.

Results: Reconstruction with flow-diverting stents was performed in all cases. The p64 was implanted in 14 patients; one of them required an additional balloon-expandable stent to reconstruct severe stenosis in the target segment. One case demanded additional liquid embolization after procedural rupture, and in one case, p64 was combined with a PED. Further 13 patients were treated exclusively with the PED. The p48MW-HPC was used in two patients, one in combination with two additional Silk Vista Baby (SVB). Moreover, one patient was treated with a single SVB, one with a SILK+. Six patients died [Glasgow Outcome Scale (GOS) 1]. Causes of death were periprocedural re-hemorrhage, thrombotic occlusion of the main pulmonary artery, and delayed parenchymal hemorrhage. The remaining three patients died in the acute–subacute phase related to the severity of the initial hemorrhage and associated comorbidities. One patient became apallic (GOS 2), whereas two patients had severe disability (GOS 3) and four had moderate disability (GOS 4). Eighteen patients showed a complete recovery (GOS 5).

Conclusion: Reconstruction of VA-DA in acute SAH with flow-diverting stents is a promising approach. However, the severity of the condition is reflected by high overall morbi-mortality, even despite technically successful endovascular treatment.

The Silk Vista Baby - The UK experience

BACKGROUND

The Silk Vista Baby (SVB) flow diverter (FDS) is the only FDS deliverable via a 0.017 inch microcatheter and is specifically designed for the distal vasculature. We sought to evaluate the safety and efficacy of the SVB.

MATERIALS AND METHODS

We performed a retrospective review to identify SVB cases at 4 tertiary neurosurgical centres within the U.K. Clinical, procedural, angiographic and follow-up data were collected.

RESULTS

We identified 60 patients (35 female, 58%) of average age 54 ± 10.5 (range 30-72) with 61 aneurysms, 50 (81.9%) located in the anterior circulation. The majority of the aneurysms treated were unruptured (46, 75.4%) and saccular (46, 75.4%). Dome size was 6.2 ± 6.2 mm (range 1-36mm) and parent vessel diameter was 2.3 ± 0.4 mm (range 1.2-3.3 mm).An average number of 1.07 devices were implanted. Coils or other devices were implanted in 14 aneurysms (23.3%). At last angiographic follow-up (n = 55), 7.5 ± 4.2 months post-procedure, 32 aneurysms (57.1%) were graded as RRC I, 7 (12.5%) RRC II, and 17 RRC III (30.4%).Clinical complications, excluding death, were seen in 4 patients (6.8%) including 1 delayed aneurysm rupture and 3 symptomatic ischaemic events. Only one patient had permanent morbidity (mRS 1). 3 patients died during follow-up (5.1%); 2 deaths were related to the aneurysms (3.4%) - one ruptured dissecting MCA aneurysm, and one giant partially thrombosed posterior circulation aneurysm. 93% of patients were mRS ≤ 2 at last follow-up.

CONCLUSION

The SVB has high rates of technical success and an acceptable safety profile. Distal aneurysms may occlude slower due to relative oversizing of the devices.

Endovascular Treatment of Intracranial Aneurysms in Small Peripheral Vessel Segments-Efficacy and Intermediate Follow-Up Results of Flow Diversion With the Silk Vista Baby Low-Profile Flow Diverter

Background and Purpose: Low-profile flow diverter stents (FDS) quite recently amended peripheral segments as targets for hemodynamic aneurysm treatment; however, reports on outcomes, especially later than 3 months, are scarce. This study therefore reports our experience with the novel silk vista baby (SVB) FDS and respective outcomes after 8 and 11 months with special respect to specific adverse events.

Materials and Methods: Forty-four patients (mean age, 53 years) harboring 47 aneurysms treated with the SVB between June 2018 and December 2019 were included in our study. Clinical, procedural, and angiographic data were collected. Follow-ups were performed on average after 3, 8, and 11 months, respectively. Treatment effect was assessed using the O'Kelly Marotta (OKM) grading system.

Results: Overall, angiographic follow-ups were available for 41 patients/45 aneurysms. Occlusion or significant reduction in aneurysmal perfusion (OKM: D1, B1–B3 and A2–A3) was observed in 98% of all aneurysms after 8 months. Only 2% of the treated aneurysms remained morphologically unaltered and without an apparent change in perfusion (OKM A1). Adverse events in the early post-interventional course occurred in seven patients; out of them, mRS-relevant morbidity at 90 days related to FDS treatment was observable in two patients. One death occurred in the context of severe SAH related to an acutely ruptured dissecting aneurysm of the vertebral artery.

Conclusion: The SVB achieves sufficient occlusion rates of intracranial aneurysms originating from peripheral segments, which are comparable to prior established conventional FDS with acceptably low complication rates. However, alteration of a hemodynamic equilibrium in distal localizations requires special attention to prevent ischemic events.

Silk Vista Baby Is a Safe and Technically Feasible Flow Diverting Stent for Distal Aneurysm Treatment

Background and Purpose: Flow diverting stents are designed to divert blood flow from the aneurysm sac, allowing for eventual occlusion following endovascular therapy. This case series reports clinical experience using the Silk Vista Baby (SVB, Balt Extrusion, Montmorency, France), a flow diverter (FD) designed to treat intracranial aneurysms in small, distal vessels.

Methods: All patients who underwent treatment with SVB at the University Hospital “Santa Maria della Misericordia” of Udine between July 2018 and September 2020 were retrospectively identified. Baseline patient and aneurysm characteristics, intraprocedural technical outcomes, periprocedural complications, modified Rankin Scale (mRS) at discharge, magnetic resonance imaging (MRI) results at 3-month follow-up, and angiographic results at 6-month follow-up were collected.

Results: A total of 18 patients (55.6% [10/18] male; mean age 62.6 years, range: 42–77 years) were retrospectively identified, receiving treatment for 22 aneurysms. Most patients were symptomatic (14/18, 77.8%) and approximately half had subarachnoid hemorrhage (10/18, 55.6%). Sufficient aneurysm coverage was achieved in 88.9% (16/18) of patients with a single device. Mortality did not occur (0/18, 0%); adverse device-related events included side branch occlusion (1/18, 5.6%) and in-stent thrombosis (1/18, 5.6%). At discharge, 77.8% (14/18) had an mRS of 0. In most cases, patients showed complete occlusion (10/15, 66.7%) or a small aneurysmal remnant (3/15, 20.0%) upon MRI; upon angiography, most showed complete occlusion (10/13, 76.9%) or only a small aneurysmal remnant (2/13, 15.4%).

Conclusion: This case series showed that the SVB FD is safe and feasible to use in patients with aneurysms in small, distal vessels. Additional randomized, prospective studies with larger cohorts are needed for the SVB.

First multicenter experience using the Silk Vista flow diverter in 60 consecutive intracranial aneurysms: technical aspects

Background

The aim of this study was to assess the technical success and procedural safety of the new Silk Vista device (SV) by evaluating the intraprocedural and periprocedural complication rate after its use in several institutions worldwide.

Methods

The study involved a retrospective review of multicenter data regarding a consecutive series of patients with intracranial aneurysms, treated with the SV between September 2020 and January 2021. Clinical, intra/periprocedural and angiographic data, including approach, materials used, aneurysm size and location, device/s, technical details and initial angiographic aneurysm occlusion, were analyzed.

Results

60 aneurysms were treated with SV in 57 procedures. 66 devices were used, 3 removed and 63 implanted. The devices opened instantaneously in 60 out of 66 (91%) cases and complete wall apposition was achieved in 58 out of 63 (92%) devices implanted. In 4 out of 66 (6%) devices a partial opening of the distal end occurred, and in 5 (8%) devices incomplete apposition was reported. There were 3 (5%) intraprocedural thromboembolic events managed successfully with no permanent neurological morbidity, and 4 (7%) postprocedural events. There was no mortality in this study. The initial occlusion rates in the 60 aneurysms were as follows: O’Kelly–Marotta (OKM) A in 34 (57%) cases, OKM B in 15 (25%) cases, OKM C in 6 (10%) cases, and OKM D in 5 (8%) cases.

Conclusions

Our study demonstrated that the use of the new flow diverter Silk Vista for the treatment of intracranial aneurysms is feasible and technically safe.

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.

Flow Diversion for Intracranial Aneurysms Beyond the Circle of Willis

Background: Few reports have shown the therapeutic outcomes of flow diversion (FD) for intracranial aneurysms beyond the circle of Willis, and the efficacy of this technique remains unclear. Materials and methods: A retrospective study was performed on 22 consecutive patients, diagnosed with intracranial aneurysms beyond the circle of Willis, and treated with pipeline embolization device (PED) (Medtronic, Irvine, California, USA) between January 2015 and December 2019. Result: The 22 patients were between 16 and 66 years old (mean 44.5 ± 12.7 years), and six patients were male (27.3%, 6/22). Twenty-two patients had 23 aneurysms. The 23 aneurysms were 3-25 mm in diameter (12.2 ± 7.1 mm on average). The diameter of the parent artery was 1.3-3.0 mm (2.0 ± 0.6 mm on average). The 23 aneurysms were located as follows: 17 (73.9%, 17/23) were in the anterior circulation, and 6 (26.1%, 6/23) were in the posterior circulation. PED deployment was technically successful in all cases. Two overlapping PEDs were used to cover the aneurysm neck in 3 cases. One PED was used to overlap the two tandem P1 and P2 aneurysms. Other cases were treated with single PED. Coil assistance was used to treat 7 aneurysms, including 4 recurrent aneurysms and 3 new cases requiring coiling assistance during PED deployment. There were no cases of complications during PED deployment. All patients were available at the follow-up (mean, 10.9 ± 11.4 months). All patients presented with a modified Rankin Score (mRS) of 0. During angiographic follow-up, complete embolization was observed in 22 aneurysms in 21 patients, and one patient had subtotal embolization with the prolongation of stasis in the arterial phase. Conclusion: PED deployment for intracranial aneurysms beyond the circle of Willis is feasible and effective, with high rates of aneurysm occlusion.

Delayed rupture of intracranial aneurysms after placement of intra-luminal flow diverter

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.

Fusiform superior cerebellar artery aneurysm treated with flow diversion: A case report

Background:

Fusiform aneurysms of the distal superior cerebellar artery are rare and challenging to treat. Due to the rarity of these lesions, there is little consensus regarding their management. Treatment options have traditionally included parent artery sacrifice with either an endovascular approach or microsurgical clipping. Given the small diameter of the superior cerebellar artery, flow diversion has not been typically considered as a viable treatment option for these aneurysms.

Case Description:

A 67-year-old female presented complaining of severe sudden onset headache. Noncontrast head CT demonstrated no intracranial hemorrhage. Head CT angiogram demonstrated a 4.2 mm fusiform aneurysm in the distal right superior cerebellar artery. The patient underwent treatment with the Pipeline embolization device which was deployed in the right superior cerebellar artery covering the aneurysm. Six-month posttreatment follow-up angiogram demonstrated resolution of the aneurysm with patency of the parent vessel.

Conclusion:

To the best of our knowledge, this is the first report of a distal superior cerebellar artery aneurysm treated with the Pipeline embolization device. The use of a Pipeline stent to create flow diversion should be considered in a case of a fusiform aneurysm of the right superior cerebellar artery. Treatment with flow diversion may allow for the treatment of the aneurysm while preserving patency of the parent vessel.

Endovascular treatment of patients with intracranial aneurysms: feasibility and successful employment of a new low profile visible intraluminal support (LVIS) EVO stent

BACKGROUND AND PURPOSE

Low-profile self-expandable stents have increased the number of intracranial aneurysms treated by endovascular means. The new low-profile visible intraluminal support device LVIS EVO (Microvention), the successor of LVIS Jr, is a self-expandable and retrievable microstent system, designed for implantation into intracranial arteries with a diameter up to 2.0 mm. In this retrospective study we aimed to elucidate the technical feasibility and clinical safety of the novel LVIS EVO stent for stent-assisted coil embolisation of intracranial aneurysms.

MATERIALS AND METHODS

A single centre technical report of the first six consecutive cases of stent-assisted coil embolisation with the novel LVIS EVO stent for the treatment of unruptured or recanalised intracranial aneurysms. Records were made of basic demographics, aneurysmal characteristics, device properties and related technical details, adverse events, clinical outcomes and occlusion rates on available radiological follow-up.

RESULTS

Six LVIS EVO devices were successfully implanted in all subjects to treat a total number of six intracranial aneurysms. No device-related intraprocedural complications were seen. At early clinical follow-up six out of six (100%) patients had a modified Ranking score of 0-1. Early angiographic and cross-sectional radiological follow-up, available in five out of six (83.3%) of the patients confirmed unchanged aneurysmal occlusion rates. A minor, transitory neurological deficit was recorded in one of the six (16.6%) patients. Mortality was 0%.

CONCLUSIONS

Preliminary experience in this subset of our patients confirms a notably improved technical behaviour of the novel LVIS EVO stent system when compared to its ancestor LVIS Jr. The enhanced visibility of the stent and the refined delivery/retrieval capabilities of the stent further increase the safety margins of the devices profile, especially in cases of tortuous anatomy.

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.

Single-Center Experience With the Bare p48MW Low-Profile Flow Diverter and Its Hydrophilically Covered Version for Treatment of Bifurcation Aneurysms in Distal Segments of the Anterior and Posterior Circulation

Background and Purpose: Flow diversion has profoundly changed the way aneurysms are treated. However, it conventionally requires dual antiplatelet medication and has yet been considered off-label use in the posterior circulation or within peripheral vessels of the anterior circulation. Here, we report our experience with the p48MW/p48MW hydrophilic coating (HPC) in the anterior and posterior circulation. This novel low-profile flow diverter is specifically designed for treatment of small peripheral vessels, and the p48MW HPC has an anti-thrombotic polymer coating, which allows application of a single antiplatelet function medication in conditions that expectably require further surgery.

Materials and Methods: Thirty-two patients were prospectively included. Twenty-six treatments were performed with one flow diverter, four required two overlapping flow diverters, one case demanded three overlapping flow diverters, and in one case, extensive dissecting aneurysm telescoping with eight flow diverters was necessary. Twenty-two complex bifurcation aneurysms were treated. Three months' follow-up was available for 14 patients.

Results: Deployment was uneventful in all cases. In four cases, undersizing was unavoidable and resulted in significant shortening of the flow diverter, which demanded implantation of further flow diverters to sufficiently treat the target aneurysm. Three flow diverters required balloon angioplasty for optimal wall approximation. All parent vessels remained patent. Available 3-month follow-up studies showed decreased influx or delayed washout in all aneurysms; none was occluded completely. There were no device-related clinical complications.

Conclusions: Implantation of the p48MW/p48MW HPC is safe and effective for treatment of distally located cerebral aneurysms. Considering the reported rates of ischemic complications associated with flow diversion of complex bifurcation aneurysms, the p48MW/p48MW HPC potentially provides increased safety for complex bifurcation aneurysms in the anterior and posterior circulation.

[Treatment of intracranial aneurysms with flow diverters]

CLINICAL ISSUE

The clinical picture of a subarachnoid haemorrhage (SAH) is associated with a high morbidity and mortality, due to the associated complications. Therefore, both unruptured and ruptured aneurysms are to be treated based on an individual and interdisciplinary treatment concept. Several endovascular procedures are already available for the treatment of intracranial aneurysms. A more recent concept is the treatment with vessel-reconstructive stents so-called flow diverters.

PRACTICAL RECOMMENDATIONS

Due to the continuous development and revision of flow diverters, the initial complication rates have been significantly reduced, which now effectively and efficiently justifies their clinical use. After careful patient selection and risk-benefit assessment, the implantation of a flow diverter can also be considered for the treatment of ruptured aneurysms and is often the only therapy option in such situations.

The p48 MW flow modulation device for treatment of unruptured, saccular intracranial aneurysms: a single center experience from 77 consecutive aneurysms

Background

The p48 MW Flow Modulation Device (phenox, Bochum Germany) is a low profile flow diverter stent (FDS), designed for implantation into intracranial arteries with a diameter of less than 3.5 mm.

Objective

To evaluate the safety and efficacy of the p48 MW FDS in the treatment of unruptured aneurysms located at intracranial arteries with less than 3.5 mm diameter based on a retrospective analysis from a single tertiary neurovascular center.

Methods

A prospectively maintained database was retrospectively reviewed to identify all cases of intracranial saccular aneurysms treated electively with the p48 MW device. Records were made of basic demographics, aneurysmal characteristics, interventional procedures, adverse events, clinical outcomes and occlusion rates on angiographic follow-ups.

Results

A total of 77 aneurysms and 74 patients were included. The mean size of the treated aneurysms was 3.5 ± 2.4 mm and the mean aspect ratio was 1.3 ± 0.4. A total of 80 endovascular procedures were performed with a total of 12 (15%) adverse events leading to two (2.5%) permanent morbidities/mortalities. Technical issues were encountered in 3 (3.9%) cases. Adequate occlusion of the treated aneurysm was recorded in 55.6% and 63.9% on the first and latest available DSA follow-ups, respectively. There were no cases of side-branch occlusion.

Conclusions

The p48 MW is an easy-to-use implant with very good safety margins. Side branch occlusion and significant in-stent stenosis are infrequently encountered. The time from implantation to sufficient aneurysm occlusion takes longer than with FDS with lower porosity.

Endovascular treatment of complex middle cerebral artery aneurysms using TuBridge flow diverters

BACKGROUND

The safety and efficacy of the TuBridge flow diverter in treating middle cerebral artery aneurysms remains unknown. In this study, we report our preliminary experience treating complex middle cerebral artery aneurysms using the TuBridge flow diverter.

METHODS

A prospectively maintained database of intracranial aneurysms treated with the TuBridge flow diverter was retrospectively reviewed, and patients with middle cerebral artery aneurysms were included in this study. Demographics, aneurysm features, complications, and clinical and angiographic outcomes were assessed. Evaluation of the angiographic results included occlusion grade of aneurysm (O'Kelly-Marotta grading scale), patency of jailed branch(es), and in-stent stenosis.

RESULTS

Eight patients with eight middle cerebral artery aneurysms were included in this study. The mean aneurysm size was 11.8 ± 6.8 mm. There were no procedure-related complications and there was no morbidity or mortality at a mean follow-up of 11.3 ± 3.6 months. All patients had follow-up angiograms at a mean of 7.5 ± 4.0 months after surgery. Of the eight patients, there was 1 (12.5%) O'Kelly-Marotta grading scale A, 3 (37.5%) O'Kelly-Marotta grading scale B, 1 (12.5%) O'Kelly-Marotta grading scale C, and 3 (37.5%) O'Kelly-Marotta grading scale D. Of the seven patients with jailed branch, the blood flow of jailed branch was unchanged in 4 (57.1%), decreased in 2 (28.6%), and occluded in 1 (14.3%). In-stent stenosis was mild in 2 (25%) patients and moderate in 1 (12.5%) patient.

CONCLUSION

Midterm results suggest that endovascular treatment of middle cerebral artery aneurysms using the TuBridge flow diverter is safe and associated with good outcomes. The TuBridge flow diverter may be an option for complex middle cerebral artery aneurysms that are difficult to treat with either clipping or coiling.

Endovascular coil embolization of proximal middle cerebral artery aneurysms has better outcomes than other middle cerebral artery aneurysms: A retrospective study

Purpose

Although some authors proposed that coil embolization in middle cerebral artery (MCA) aneurysms is a useful and effective alternative, the characteristics of the aneurysms may be different at each location. We compared the results of coil embolization of proximal middle cerebral artery aneurysms with those of other middle cerebral artery aneurysms.

Methods

Data from 46 patients with 50 aneurysms were retrospectively evaluated. We defined the aneurysms inside of the insular cortex as proximal MCA (pMCA) aneurysms and those outside of the insular cortex as non-proximal MCA (npMCA) aneurysms. The results of the occlusion were divided into classes 1, 2, and 3 of the Raymond scale. We collected the results of the occlusion from the operative notes supplied by a neuroendovascular specialist.

Results

Univariate analysis identified favorable results for pMCA aneurysms (class 1: pMCA = 22 npMCA = 11; P < 0.01). In the radiological follow-up results, we achieved class 1 in 29 patients (69%; pMCA = 21 and npMCA = 8; P < 0.01). Side wall type aneurysms (pMCA = 14, npMCA = 2; P < 0.01) and the number of branches from the neck of ≤1 (pMCA = 14, npMCA = 2; P < 0.01) were significantly recognized at the pMCA.

Conclusions

Proximal middle cerebral artery aneurysm clipping is difficult because the origin of the lenticulostriate arteries is often hidden behind the aneurysmal dome. In the present study, endovascular coil embolization for pMCA aneurysms obtained better results than that for npMCA aneurysms because of the morphological characteristics. Endovascular coil embolization seems to be efficacious for pMCA aneurysms as compared with npMCA aneurysms.

Distal anterior cerebral artery aneurysms treated with flow diversion: experience of a large-volume center and systematic review of the literature

BACKGROUND

Evidence about the safety and the efficacy of flow diversion for distal anterior cerebral artery (DACA) aneurysms is scant. To provide further insight into flow diversion for aneurysms located at, or distal to, the A2 segment.

METHODS

Consecutive patients receiving flow diversion for DACA aneurysms were retrieved from our prospective database (2014-2020). A PRISMA guidelines-based systematic review of the literature was performed. Aneurysm occlusion (O'Kelly-Marotta=OKM) and clinical outcomes were evaluated.

RESULTS

Twenty-three patients and 25 unruptured saccular DACA aneurysms treated with flow diversion were included. Aneurysm size ranged from 2 mm to 9 mm (mean size 4.5 mm, SD ±1.6). Mean parent artery diameter was 1.8 mm (range, 1.2-3 mm, SD ±0.39). Successful stent deployment was achieved in all cases. Angiographic adequate occlusion (OKM C-D) at follow-up (14 months) was 79% (19/24 available aneurysms). No cases of aneurysm rupture or retreatment were reported. Univariate analysis showed a significant difference in diameter among aneurysms with adequate (4 mm) vs incomplete occlusion (7 mm) (P=0.006).There was one transient perioperative in-stent thrombosis, and three major events causing neurological morbidity: two stent thromboses (one attributable to the non-adherence of the patient to the antiplatelet therapy); and one acute occlusion of a covered calloso-marginal artery.Results from systematic review (12 studies and 107 A2-A3 aneurysms) showed 78.6% (95% CI=70-86) adequate occlusion, 7.5% (95% CI=3.6-14) complications, and 2.8%, (3/107, 95% CI=0.6-8.2) morbidity.

CONCLUSIONS

Flow diversion among DACA aneurysms is effective, especially among small lesions. However, potential morbidity related to in-stent thrombosis and covered side branches should be considered when planning this strategy.

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.

Coiling for an unruptured saccular aneurysm at the non-branching segment of the distal anterior cerebral artery: Case report and literature review

BACKGROUND

Saccular aneurysms in the non-branching segment of the distal anterior cerebral artery (DACA) are extremely rare. Here, we describe the first case of coil embolization using a simple, non-adjunctive technique for an aneurysm at this rare location.

CASE DESCRIPTION

A 74-year-old man with an asymptomatic, unruptured aneurysm of the right DACA was followed up annually for 3 years by medical checkup. Endovascular treatment was proposed because of a slight angiographic change in the shape of the aneurysm in the past year. The aneurysm at the non-branching site of the right calloso-marginal artery was 2 mm distal to the origin, and measured 3 mm in height and 3.3 mm in width, with a neck measuring 1.7 mm wide; the calloso-marginal artery diameter was 1.6 mm. The aneurysm was successfully embolized with a simple technique using a Pre-Shaped S Microcatheter and two coils.

CONCLUSIONS

The simple, non-adjunctive technique for coil embolization of saccular side-wall type aneurysm in the non-branching segment of the DACA could be performed using the appropriate catheter and a softer coil.

Flow diversion in challenging vascular anatomies: the use of low profile stent retrievers for safe and accurate positioning of the microcatheter

Background

Hemodynamic therapy with Flow-Diverters has become a fundamental option for treatment of cerebral aneurysms. A major obstacle of Flow-Diverters is the comparatively stiff microcatheter required for implantation. Consequentially, maneuverability is limited and primary catheterization of peripheral targets may be difficult or even futile in challenging vascular anatomies. To overcome this, a highly navigable microcatheter must be used to attain the desired vascular segment, followed by a hardly controllable exchange-maneuver via a long microwire, involving a high risk for wire-perforation. Our study aimed to investigate the value of low-profile stent-retrievers as a railway for introduction of the required microcatheter, which allows to maintain a stable endovascular position and reduce the risk for procedural vessel injury.

Methods

14cases (8females, mean-age 59y) of Flow-Diverter-Implantation requiring the use of a low-profile stent-retriever were reviewed. All cases featured a challenging vascular anatomy. After micro-catheterization of the desired segment, the stent-retriever was carefully deployed as an anchor in a secure, distal location. In all cases a pREset/LITE-stent-retriever was used for introduction of the equipment required for implantation.

Results

In all cases the anchoring-maneuver was performed without technical complications. The stent-retrievers maintained a stable position after deployment in all situations. No potential traumatic sudden movements of the microcatheter occurred. No procedure-related perforations, dissections or vasospasms were observable during the interventions or their aftermath.

Conclusions

In our experience the stent-retriever-anchoring-maneuver represents a potentially essential and safe amendment for flow diverter treatment in technically challenging situations.

The use of single low-profile visualized intraluminal support stent-assisted coiling in the treatment of middle cerebral artery bifurcation unruptured wide-necked aneurysm

OBJECTIVE

Endovascular treatment of unruptured wide-necked aneurysms located at the middle cerebral artery bifurcation remains challenging. This study aimed to evaluate the safety and efficacy of endovascular treatment for middle cerebral artery bifurcation unruptured wide-necked aneurysms using a low-profile visualized intraluminal support (LVIS) stent.

METHODS

We retrospectively reviewed all patients with middle cerebral artery bifurcation unruptured wide-necked aneurysms treated using an LVIS device at our institution between October 2014 and December 2018. Clinical presentation, aneurysmal characteristics, technical feasibility, perioperative complications, clinical outcome, and angiographic and clinical follow-up results were evaluated.

RESULTS

Fifty-seven patients with 57 wide-necked aneurysms arising from the middle cerebral artery bifurcation were identified. The technical success rate of stent deployment was 100%. Immediate postoperative angiograms showed Raymond 1 in 26 aneurysms (45.6%), Raymond 2 in 10 (17.6%), and Raymond 3 in 21 (36.8%). Perioperative complications developed in two patients (3.5%), including one procedure-related hemorrhagic event and one thromboembolic event. The follow-up angiogram was available for 47 aneurysms obtained at an average of 11.7 months (range, 5 to 49 months) after intervention; the latest follow-up angiograms revealed complete occlusion in 37 (78.7%) aneurysms, improvement in three (6.4%), stabilization in five (10.6%), and recanalization in two (4.3%). During the follow-up, one patient was found to have in-stent stenosis and two patients were found to have slow flow or occlusion of the jailed branch. All three of these patients were asymptomatic. No hemorrhagic or thromboembolic events occurred during clinical follow-up.

CONCLUSIONS

Our experience suggests that endovascular treatment of middle cerebral artery bifurcation unruptured wide-necked aneurysms with an LVIS stent is safe and effective, but the effect on branches needs to be further studied.

Cerebral aneurysms treated with low-profile visualized intraluminal support device (LVIS Jr) Y-stent constructs: Technical experience with a single microcatheter technique

BACKGROUND

The LVIS Jr device holds a number of advantages but poses unique technical challenges compared to such, especially, complex multistent constructs. We report our experience with the technical feasibility and early to mid-term outcomes of Y-stent-assisted coiling with the LVIS Jr using a simple, single microcatheter technique.

METHODS

Using a departmental database, we retrospectively reviewed a single surgeon's experience with Y-stent-assisted coiling with LVIS Jr over a three-year period. Eighteen aneurysms in 17 patients were treated over this period. We assessed the technical success of the procedures, the initial and follow-up radiographic success with the modified Raymond-Roy occlusion score and follow-up clinical outcome with the modified Rankin scale.

RESULTS

All stents were successfully deployed, and 17 of 18 aneurysms were successfully coiled at the initial treatment for a technical success rate of 94.4%. Of the 17 aneurysms with follow-up imaging, all were modified Raymond-Roy grade 1 or 2. One aneurysm required retreatment for coil compaction and a growing neck. There were two immediate postprocedure symptomatic strokes and one delayed stroke related to antiplatelet non-compliance. The two immediate symptomatic strokes recovered to neurological baseline with no residual deficits by the time of discharge. The long-term morbidity rate was 5.5%. The mortality rate was 0%. All patients had a modified Rankin Scale ≤ 2 at most recent follow-up.

CONCLUSION

Treatment with LVIS Jr Y-stent constructs via a single microcatheter technique is technically feasible with good radiographic and clinical outcomes.

Delayed Stroke after Aneurysm Treatment with Flow Diverters in Small Cerebral Vessels: A Potentially Critical Complication Caused by Subacute Vasospasm

Flow diversion (FD) is a novel endovascular technique based on the profound alteration of cerebrovascular hemodynamics, which emerged as a promising minimally invasive therapy for intracranial aneurysms. However, delayed post-procedural stroke remains an unexplained concern. A consistent follow-up-regimen has not yet been defined, but is required urgently to clarify the underlying cause of delayed ischemia. In the last two years, 223 patients were treated with six different FD devices in our center. We identified subacute, FD-induced segmental vasospasm (SV) in 36 patients as a yet unknown, delayed-type reaction potentially compromising brain perfusion to a critical level. Furthermore, 86% of all patients revealed significant SV approximately four weeks after treatment. In addition, 56% had SV with 25% stenosis, and 80% had additional neointimal hyperplasia. Only 13% exhibited SV-related high-grade stenosis. One of those suffered stroke due to prolonged SV, requiring neurocritical care and repeated intra-arterial (i.a.) biochemical angioplasty for seven days to prevent territorial infarction. Five patients suffered newly manifested, transient hemicrania accompanying a compensatorily increased ipsilateral leptomeningeal perfusion. One treated vessel obliterated permanently. Hence, FD-induced SV is a frequent vascular reaction after FD treatment, potentially causing symptomatic ischemia or even stroke, approximately one month post procedure. A specifically early follow-up-strategy must be applied to identify patients at risk for ischemia, requiring intensified monitoring and potentially anti-vasospastic treatment.