Comparison of the Pipeline embolisation device alone or combined with coiling for treatment of different sizes of intracranial aneurysms

The utility of the PK papyrus covered stent in neurointervention: A prospective study on safety, efficacy, and aneurysm occlusion rates

BACKGROUND

Covered stents have become increasingly utilized in neurovascular interventions due to their ability to achieve immediate lesion occlusion while preserving the parent vessel. The PK Papyrus stent is a thinner balloon mounted covered stent that has been used off-label in neurointerventions, but there is limited evidence regarding its performance and clinical benefits. This study aims to evaluate the PK Papyrus stents safety, efficacy, and occlusion rates in managing complex neurovascular pathologies.

METHODS

We conducted a retrospective analysis of a prospectively enrolling study that included 13 patients. The primary outcome was the rate of complete aneurysm and carotid-cavernous fistula (CCF) occlusion. Secondary outcomes focused on safety, including the incidence of periprocedural complications, device-related complications, and adverse events.

RESULTS

The study included 13 patients, with 46.1 % being female. The median modified Rankin Scale (mRS) at presentation was 1. The PK Papyrus stent was successfully deployed in all cases (100 %). No periprocedural complications were encountered. Additionally, there were no device-related complications, including stent fracture or in-stent stenosis. Over a median follow-up duration of 6 months, all treated lesions remained completely occluded, with stable vessel patency and no evidence of recurrence or recanalization. No adverse events or neurological deficits were reported among the patients.

CONCLUSION

This study indicates that the PK Papyrus covered stent is a safe and effective option for managing complex neurovascular pathologies. It demonstrated a high technical success rate, with no periprocedural or device-related complications, supporting its use as a promising alternative to other endovascular modalities in select cases.

Flow diverter is valid for aneurysms with incorporated branch vessels: Adding coil embolization and incorporated branch vessel diameter are predictors of treatment efficacy

BACKGROUND

This study aimed to determine the efficacy of flow diverters (FDs) for small/medium (≤10 mm) aneurysms and analyzed the factors that prevent aneurysm occlusion.

METHODS

This retrospective single-center study evaluated the angiographic and clinical data of consecutive patients between June 2020 and February 2023.

RESULTS

Overall, 121 small/medium aneurysms were observed in 106 patients treated with FDs. The median dome diameter was 6.1 (5.1-7.2) mm. Symptomatic thromboembolic complications were observed in four (3.7 %) patients, and none showed a major ischemic stroke. Intracranial hemorrhage was detected using postprocedural computed tomography in one (0.9 %) patient with asymptomatic subarachnoid hemorrhage. The rate of permanent neurological deficits was 1.8 %, and the mortality rate was 0 %. No delayed ischemic or hemorrhagic complications were observed during follow-up. Angiographic follow-up revealed complete and adequate occlusion (O'Kelly-Marotta grades C and D) rates of 77.5 % and 90.8 %, respectively. On multivariate analysis, incomplete occlusion was only associated with the presence of a branch vessel from the aneurysm dome (P < 0.01). In aneurysms with incorporated branch vessels, univariate analysis revealed that coil usage was a predictor of complete occlusion (P = 0.03). Moreover, even without using coils, effective occlusion was achieved when the branch vessel diameter was small (P = 0.03).

CONCLUSIONS

FDs are an effective and safe treatment option for small/medium aneurysms. The presence of incorporated branch vessels can predict incomplete occlusion. Even in aneurysms with incorporated branch vessels, FD can obtain therapeutic effects by adding coil embolization or treating with only FD if the branch vessel diameter is small.

Comparison of PED Flex and Lattice flow diverter in the treatment of unruptured intracranial aneurysms

Background and objective

Flow diverters (FDs) are widely used in the treatment of intracranial aneurysms (IAs). The Lattice flow diverter (LFD) is a novel FD developed in China, specifically designed for large or giant IAs. Currently, few studies have compared various FDs in the treatment of these conditions. This study endeavors to contrast the safety and efficacy of the Pipeline Flex embolization device (PED Flex) and LFD in the treatment of unruptured intracranial aneurysms (UIAs).

Methods

This study retrospectively reviewed cases of UIAs managed with PED Flex or LFD at the Department of Interventional Radiology, Kunming Medical University's First Affiliated Hospital from March 2022 to September 2024. We analyzed demographic characteristics, aneurysm features, medical history, complications, aneurysm occlusion, and clinical outcomes.

Results

The study cohort consisted of 99 patients with 99 aneurysms, including 48 treated with PED Flex and 51 with LFD. The median follow-up duration was 9 months for both groups. Rates of complete aneurysm occlusion (81.3% vs. 78.4%, p = 0.727), successful aneurysm occlusion (87.5% vs. 86.3%, p = 0.857), and complication rates (2.1% vs. 3.9%, p = 0.727) did not differ significantly between the groups. Similarly, rates of in-stent stenosis (ISS) (14.6% vs. 11.8%, p = 0.678) and positive clinical outcomes were comparable.

Conclusion

Our preliminary findings indicate that compared with PED Flex, the new domestic LFD has similar safety and effectiveness in treating UIAs. It is a new option for treating intracranial aneurysms and may have broad application prospects.

Coil embolization strategy after flow diverter deployment in patients with intracranial vertebral artery dissection aneurysms: a study from a hemodynamic viewpoint

Flow diverter (FD) deployment combined with coil therapy is effective and considered superior to FD deployment alone for treating large, complex anterior circulation aneurysms. However, the optimal strategy for coil usage in posterior circulation aneurysms, particularly intracranial vertebral artery dissection aneurysms (IVADAs), remains unclear. This study used patient-specific aneurysm models and finite element analysis to determine the ideal packing density (PD) of coils following FD placement in IVADAs. We prospectively analyzed 22 patients with 24 aneurysms, all treated with FD at our hospital. Hemodynamic parameters were analyzed before treatment, after FD alone, and at three different coiling rates (5%, 15%, and 25%) using software simulation. All 22 patients underwent FD procedures to treat IVADAs. FD deployment and additional coil use both reduced the inflow rate at the aneurysm neck, the inflow concentration index, and the mean velocity in the aneurysm. However, compared with FD treatment alone, coils provided a smaller reduction in these parameters. No significant difference in the reduction ratio was observed when the coiling PD increased from 5 to 15% and then to 25%. Further coil addition beyond a 5% PD produced no notable hemodynamic benefits. Adjunct coiling improves the post-FD hemodynamic environment of treated IVADAs. However, dense packing is unnecessary because the intra-aneurysmal hemodynamics tend to stabilize once the PD reaches approximately 5%.

Clinical Outcome of Pipeline Embolization Device with and without Coils to Treat Intracranial Aneurysm: A Systematic Review and Meta-Analysis

BACKGROUND

The use of a Pipeline Embolization Device (PED) in combination with coils (PEDC) to treat intracranial aneurysms remains unclear as to whether it offers significant benefits for the patients because the results have varied.

PURPOSE

This study aimed to investigate the clinical outcome of the PEDC compared with the PED in treating intracranial aneurysms.

DATA SOURCES

We systematically searched the articles from PubMed, Web of Science, and the Cochrane Library databases published before January 25, 2024.

STUDY SELECTION

We selected studies comparing the PEDC versus the PED to treat intracranial aneurysms. Patients treated with the PEDC but using dense coiling were excluded from the study.

DATA ANALYSIS

The clinical outcomes observed in this meta-analysis were intraprocedural complications, postoperative complications (stenosis, stroke, hemorrhage, mortality), favorable outcome (mRS ≤2), complete occlusion rate, and retreatment rate. A forest plot was used to analyze pooled OR of clinical outcomes.

DATA SYNTHESIS

A total of 3001 subjects from 9 observational studies were included. The PEDC was mainly used to treat larger aneurysms. The PEDC has a significantly higher complete occlusion rate at 6 months (OR = 2.66; 95% CI, 1.26-115.59; P = .01), a lower retreatment rate (OR = 0.18; 95% CI, 0.05-0.07; P = .010), higher stroke-related complications (OR= 1.66, 95% CI, 1.16-2.37; P = .005), and higher hemorrhage-related complications (OR = 1.98; 95% CI, 1.22-13.21; P = .005). There was no significant difference in intraprocedural complications, stenosis-related complications, mortality, favorable outcomes, and complete occlusion at the end of the study.

LIMITATIONS

No randomized controlled trials have been performed comparing the PEDC and PED. Considering that all the included studies were observational, the patients' baseline characteristics were not completely balanced.

CONCLUSIONS

This meta-analysis study showed that the PEDC in large intracranial aneurysms induces a faster complete occlusion rate at 6 months and a lower retreatment rate. However, it increases the risk of stroke-related postoperative complications, and the faster complete aneurysm occlusion rate found in this study did not correlate with a reduction in long-term aneurysm or distal artery ruptures. Thus, this study suggests the need to find a better strategy to improve long-term hemorrhage-related complications in large intracranial aneurysms.

Comparison of flow diverter alone versus flow diverter with coiling for large and giant intracranial aneurysms: systematic review and meta-analysis of observational studies

BACKGROUND

Large and giant intracranial aneurysms pose treatment challenges. The benefit-risk balance of flow diverters (FDs) alone versus FDs with coiling remains unclear. This study aimed to compare these two strategies.

METHODS

This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A comprehensive search of PubMed, Embase, Scopus, Cochrane, and Web of Science was performed up to October 2024. Studies comparing FDs with or without adjunctive coiling in large/giant intracranial aneurysms were included. The primary outcome was complete aneurysm occlusion, defined by the Raymond-Roy Occlusion Classification. Additional outcomes included procedural and postprocedural complications. Data were analyzed using a random effects model.

RESULTS

15 studies with 1130 patients were analyzed, with 557 in the FD alone group and 573 in the FD+coiling group. The meta-analysis revealed that FD+coiling significantly improved complete aneurysm occlusion rates (OR 1.59, 95% CI 1.06 to 2.40, P=0.03). While overall ischemic complications were significantly lower in the FD alone group, a sensitivity analysis showed no significant difference (OR 0.49, 95% CI 0.20 to 1.23, P=0.13). Subgroup analysis of fusiform aneurysms showed no significant difference in complete aneurysm occlusion rates (OR 1.10, 95% CI 0.50 to 2.40, P=0.82). Procedural and hemorrhagic complications did not differ significantly, and no publication bias was detected in the results.

CONCLUSIONS

Combining FDs with coiling improved complete aneurysm occlusion rates in large and giant saccular intracranial aneurysms, although the impact on complications remains controversial. Further investigation into the benefit-risk ratio of this combined approach is warranted.

Long-term Safety and Efficacy of the Derivo Embolization Device in a Single-center Series

PURPOSE

This study analyzes the long-term clinical and angiographic outcomes of the Derivo Embolization Device (DED), an advanced flow diverter device with an electropolished surface, for the treatment of intracranial aneurysms.

METHODS

A consecutive series of 101 patients (mean age: 58 years, 72% female) treated with the DED for 122 aneurysms at a single center between 2017 and 2023 was retrospectively analyzed for major (change in National Institutes of Health Stroke Scale [NIHSS] score ≥ 4 points) and minor (change in NIHSS score < 4 points) neurological events, procedural morbidity (increase of at least one point on the modified Rankin Scale), and angiographic results.

RESULTS

There were 14 (11%) recurrent aneurysms, 15 (12%) ruptured aneurysms, 26 (21%) posterior circulation aneurysms and 16 (13%) fusiform or dissecting aneurysms. Device deployment failed in 1 case (1%). Procedure-related symptomatic procedural complications consisted of 2 (2%) major events (1 major stroke and 1 vessel perforation with intracranial hemorrhage and infarction) and 6 minor events (6 minor strokes). Procedural morbidity was 5%. There were no late ischemic or hemorrhagic events during follow-up. Complete and favorable aneurysm occlusion was achieved in 54% (40/74) and 62% (46/74) at a mean of 5 months, 71% (27/38) and 87% (33/38) at a mean of 12 months, and 76% (25/33) and 97% (32/33) at a mean of 35 months, respectively.

CONCLUSION

The results demonstrate progressive aneurysm occlusion beyond 12 months after DED implantation with an almost 100% favorable occlusion rate. Procedural morbidity was low and there were no late complications.

Analysis of Current Evidence in the Endovascular Treatment of Intracranial Aneurysms: A Systematic Review and Proposal for a Reporting Guideline to Enhance Reproducibility and Comparability of Surgical and Clinical Outcomes

BACKGROUND AND OBJECTIVES

Endovascular therapy (EVT) has recently become the most widely used treatment method for intracranial aneurysms (IAs). However, the literature on this topic is heterogeneous, with studies assessing and reporting surgical and clinical outcomes in different ways, lacking standardization. We aimed to evaluate the quality of these studies and propose a reporting guideline focusing on essential elements to ensure reproducibility and comparability.

METHODS

After Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, we searched Medline, Embase, Cochrane Library, and Web of Science databases. Eligible studies were observational or randomized, reported clinical and/or surgical outcomes of EVTs for IAs, included over 200 patients, and were published in English between January 1, 2022, and January 1, 2024. Studies were assessed focusing on key domains: (1) reporting on the baseline characteristics of the patient sample, (2) assessment and reporting on imaging methods and aneurysm characteristics, (3) reporting on pivotal concepts definitions, (4) reporting on operator(s) and staff characteristics, (5) reporting on anesthetic protocol, (6) reporting on antiaggregant and anticoagulation therapy, (7) reporting on surgical details, (8) assessing and reporting clinical and surgical outcomes, and (9) reporting retreatment details.

RESULTS

Thirty-nine studies comprising 79 604 patients were included. Our assessment revealed substantial gaps in the literature on EVTs for IAs, including deficiencies across all domains. An EndoIAs Reporting Guideline was developed, consisting of 74 items distributed across 10 domains, focusing on key surgical and clinical outcomes.

CONCLUSION

Substantial deficiencies were identified in data collection and outcomes reporting in the available literature on EVT for IAs, thereby impeding comparability and reproducibility and hindering the building of cumulative evidence. The aim of the proposed EndoIAs Reporting Guideline was to address these fundamental aspects and has the potential to enhance the reproducibility and comparability of future studies, thereby fostering the building of cumulative and reliable evidence of EVT for IAs.

Comparison of a covered stent and pipeline embolization device in intracranial aneurysm: a propensity score matching analysis

BACKGROUND

The Willis covered stent (WCS) and pipeline embolization device (PED) have partly overlapping therapeutic indications. However, the differences of effect between these two treatments remain unclear.

OBJECTIVE

To compare clinical outcome, angiographic outcome, and complications following treatment with a WCS versus PED.

METHODS

Patients with intracranial aneurysms treated by a WCS or PED between January 2015 and December 2020 were included. The primary outcomes were complications, clinical outcome (modified Rankin Scale score >2), and angiographic outcome (incomplete aneurysm occlusion). Propensity score matching was conducted to adjust for potential confounding factors.

RESULTS

A total of 94 aneurysms treated by WCS and 698 aneurysms by PED were included. Compared with the PED group, patients in the WCS group are younger, a greater number have a poor condition at admission, a larger proportion of ruptured, non-saccular, and anterior circulation aneurysms, a smaller aneurysm neck width, and less coiling assistance is required. A total of 42 (44.7%) branches were covered by WCS. After adjustment for age, sex, aneurysm type, rupture status, neck size, aneurysm location, and coiling, 50 WCS and PED pairs were examined for internal carotid artery aneurysms. No significant differences were observed in clinical (10.4% vs 2.1%, P=0.206) and angiographic outcomes (12.8% vs 18.2%, P=0.713). However, 27 branches covered by WCS, including 22 ophthalmic arteries and five posterior communicating arteries. Patients in the WCS group had a higher intraoperative complication rate than those in the PED group (28% vs 6%, P=0.008), especially in the occlusion rate of covered branches (51.9% vs 11.1%, P<0.001).

CONCLUSION

The comparable clinical and angiographic outcomes of WCS or PED demonstrate the therapeutic potential of WCS as a viable alternative for aneurysms. However, the complication of occlusion of covered branches might not be negligible.

Treatment Outcome of Flow Diverter Device for Medium-Sized Cerebral Aneurysms: A Single-Center Report

Objective

Flow diverters (FDs), first introduced in Japan in 2015, were initially limited to wide-necked large cerebral aneurysms, which pose a high treatment risk. However, based on the results of the PREMIER study, the indications have expanded since 2020, and the number of treatment cases is increasing in Japan. At our hospital, FD placement with adjunctive coil embolization has been actively performed for medium-sized cerebral aneurysms, as indicated in the PREMIER study; herein, we report the outcomes of this treatment.

Methods

Of the 25 patients with 28 aneurysms who underwent FD placement at our institution between April 2022 and June 2023, 15 with 17 wide-necked unruptured cerebral aneurysms with a maximum diameter of <12 mm in the internal carotid artery (ICA) or vertebral artery (VA) were included. Postoperative complications were investigated in each case, and the aneurysm occlusion status was assessed using ultrashort echo time (UTE)-MRA at 3 months postoperatively and angiography at 6 months postoperatively. Fifteen patients who underwent coiling or stent-assisted coiling (SAC) for the same criteria during the same period were compared. Baseline characteristics and treatment results were compared between FD and coiling/SAC cases.

Results

Four males and 11 females with a mean age of 61.7 ± 12.8 years were included, and the median follow-up period was 9 months (6-18 months). There were 14 aneurysms of the ICA and 3 of the VA, and the mean maximum aneurysm diameter was 7.9 ± 1.7 mm. All patients were treated using the Pipeline Flex with Shield Technology (Medtronic, Minneapolis, MN, USA), and 14 aneurysms (82.4%) were treated with adjunctive coil embolization. There were no symptomatic strokes in the perioperative period; only one patient receiving corticosteroid therapy for thyroid eye disease had asymptomatic ICA occlusion at 3 months. Fifteen aneurysms (88.2%) were not visible on UTE-MRA at 3 months postoperatively, and angiography at 6 months showed complete occlusion in 16 (94.1%) aneurysms. The coiling/SAC group had a smaller neck size and higher volume embolization ratio than the FD group; however, complete occlusion was higher in the FD group.

Conclusion

FD placement with adjunctive coil embolization for medium-sized cerebral aneurysms is expected to result in good occlusion rates in the early postoperative period.

Pipeline embolization device versus Atlas stent assisted coiling for intracranial aneurysm treatment: a retrospective, propensity score matched study with a focus on midterm outcomes and hospital costs

BACKGROUND

Stent assisted coiling (SAC) and flow diverters (FDs) are common endovascular treatments for wide necked cerebral aneurysms, but studies comparing the new generation Atlas SAC and FDs are scarce. We performed a propensity score matched (PSM) cohort study to compare the Atlas SAC and the pipeline embolization device (PED) for proximal internal carotid artery (ICA) aneurysms.

METHODS

Consecutive ICA aneurysms treated at our institution with either the Atlas SAC or PED were studied. PSM was used to control for age, sex, smoking, hypertension, and hyperlipidemia, and the rupture status, maximal diameter, and neck size of the aneurysm (aneurysms >15 mm and non-saccular aneurysms were excluded). Midterm outcomes and hospital costs were compared between these two devices.

RESULTS

A total of 309 patients with 316 ICA aneurysms were included. Following PSM, 178 aneurysms treated with the Atlas SAC and PED were matched (n=89 in each group). Aneurysms treated with the Atlas SAC required a slightly longer procedure time, but had lower hospital costs than those treated with the PED (115.2±24.6 vs 102.4±40.8 min, P=0.012; $27 650.2±$6961.4 vs $34 107.0±$3707.2, P<0.001). Atlas SAC and PED treatments showed equivalent aneurysm occlusion rates (89.9% vs 86.5%, P=0.486), complication rates (5.6% vs 11.2%, P=0.177), and a favorable functional outcome (96.6% vs 97.8%, P=1.0) at follow-up (8.2±3.0 vs 8.4±4.2 months, P=0.652).

CONCLUSION

In this PSM study, midterm outcomes of the PED and Atlas SAC in the treatment of ICA aneurysms were similar. However, SAC required a longer operation time, and the PED may increase the economic cost of inpatients in Beijing, China.

Comparison Between the Efficacy of a Flow Diverter and Interventional Trapping with Bypass in the Treatment of Unruptured Large- or Giant-Sized ICA Aneurysms

OBJECTIVE

Management of large- or giant-sized internal carotid artery aneurysms (LICAAs) remains challenging. Whether a flow diverter device (FDD) or interventional trapping with extracranial-intracranial bypass (ITB) is better, remains unclear.

METHODS

We conducted a multicenter retrospective analysis of unruptured LICAA patients treated with FDD or ITB at 3 medical centers. Both the effectiveness and safety results of FDD and ITB were compared.

RESULTS

In total, 101 aneurysms in 95 patients treated with FDDs and 36 aneurysms in 36 patients managed with ITBs were included (September 2014-June 2021). There was no significant difference between the groups in the complete obliteration rate 1 year after surgery (P = 0.101). There were 2 relapse cases (2.0%) and 4 retreated cases (4.0%) in the FDD group and 1 relapse case (2.8%) and 2 retreated cases (5.6%) in the ITB group. Neither the relapse rates nor retreat rates between groups were significantly different. The neurological morbidity rates were 4.0% (4/101) and 2.8% (1/36) in the FDD group and ITB group, respectively, and were not significantly different. There was 1 mortality case in each group, and the mortality rates were not significantly different (P = 0.443). Both the perioperative and overall (perioperative plus long-term) complication rates in the FDD group were significantly lower than those in the ITB group (P = 0.033, P = 0.039).

CONCLUSIONS

FDD had comparable surgical efficacy and a significantly lower postoperative complication rate to traditional ITB. FDD might be preferable to ITB as a treatment modality for LICAA.

Use of the Neuroform Atlas stent for wide-necked cerebral aneurysms

To investigate the effect and safety of the Neuroform Atlas (NFA) stent in stent-assisted coiling of wide-necked intracranial aneurysms, patients with wide-necked intracranial aneurysms were retrospectively enrolled and treated with the NFA stent-assisted coiling. The modified Rankin scale (mRS) grades and Raymond grades were used to assess the clinical outcomes and aneurysm occlusion degrees, respectively, after embolization and at follow-up. Totally, 122 patients were enrolled with 129 wide-necked aneurysms, and forty-nine (40.2%) patients experienced subarachnoid hemorrhage. A total of 134 NFA stents were deployed in all patients. Immediately after endovascular embolization, the Raymond grade was I in 112 (86.8%), II in 8 (6.2%), and III in 9 (7.0%). Complications occurred in 7 (5.7%) patients, including stent displacement in 2 (1.6%) patients, thrombosis and cerebral infarction in 4 (3.3%), and death in 1 (0.8%). Clinical follow-up was performed in 113 (92.6%) patients 6-30 (mean 21) months after embolization, with the mRS grade 0 in 99 (87.6%) patients, 1 in 7 (6.2%), 2 in 5 (4.4%), and 3 in 2 (1.8%). Good prognosis (mRS ≤ 2) was achieved in 111 (98.2%) patients while poor prognosis (mRS > 2) in two (1.8%). Digital subtraction angiography was conducted in 98 (80.3%) patients with 104 (80.6%) aneurysms 6-30 (mean 21) months after embolization. The Raymond grade was grade I in 94 (90.4%) aneurysms, II in 4 (3.8%), and III in 6 (5.8%). Compared with the Raymond grades immediately after embolization, 93 (89.4%) aneurysms disappeared, 9 (8.7%) remained unchanged in the occlusion status, and 2 (1.9%) were recurrent. In conclusion, the NFA stent may have a high aneurysm occlusion rate and a low complication rate in assisting coiling of wide-necked intracranial aneurysms even though further studies are necessary to prove this.

Flow diversion for posterior circulation aneurysms: a multicenter retrospective study

Background

The prevalence of intracranial aneurysms is approximately 3% worldwide. Posterior circulation (PC) aneurysms have a higher risk of treatment complications than anterior circulation aneurysms. Improving the survival rate and quality of life of patients with PC aneurysms remains one of the most important issues in the field.

Objectives

Flow diverter (FD) treatment of PC aneurysms remains controversial. We aimed to investigate the effects of FD treatment and analyze differences among different application methods or aneurysm types in PC aneurysms.

Design

This is a multicenter retrospective study.

Methods

Patients with PC aneurysms treated with the pipeline embolization device (PED) or Tubridge embolization device (TED) between 2015 and 2020 in five neurovascular centers were retrospectively enrolled. The primary outcomes were major perioperative complication, clinical outcome, and aneurysm occlusion rates. Univariable and multivariable logistic regression analyses were used to determine the risk factors of each outcome.

Results

In total, 252 aneurysms were included. Major perioperative complication, favorable clinical outcome, and complete occlusion rates were 7.5%, 91.0%, and 79.1%, respectively. Compared with other types of aneurysms, dissecting aneurysms had the best clinical outcome and highest occlusion rate. Both clinical and angiographic outcomes were independently associated with the aneurysm location at the basilar artery. Aneurysm size was not associated with any outcome. TED had similar clinical and angiographic outcomes compared with PED but more perioperative major complications. Tandem treatment and coiling assistance may have poorer clinical outcomes but similar occlusion rates. Single- and multiple-stent treatments had similar outcomes.

Conclusion

FD treatment of PC aneurysms achieved favorable clinical outcomes and long-term aneurysm occlusion rates with acceptable perioperative complication rates, especially in dissecting and non-basilar artery aneurysms. There was no additional improvement in outcomes with coiling assistance, multi-stent application, or tandem treatment. Therefore, the use of PC aneurysms should be carefully considered.

Flow diversion effect of the leo braided stent for aneurysms in the posterior and distal anterior circulations: A multicenter cohort study

Background and purpose

The treatment of aneurysms located in the posterior and distal anterior circulations remains a challenge. Leo stents with a flow diversion (FD) effect may be a potential option, which needs to be clearly studied.

Methods

From January 2016 to October 2021, 133 patients with 145 aneurysms in the posterior and distal anterior circulations, treated with Leo stents, were retrospectively analyzed in three neurosurgical centers. Data on demographic information, aneurysm characteristics, procedural outcomes, postoperative course, and aneurysm occlusion were retrospectively analyzed.

Results

After immediate surgery, 90 aneurysms (60.1%) were in complete occlusion [Raymond-Ray Occlusion Class (RROC) 1 and O'Kelly Marotta (OKM) grade D], 29 aneurysms (20%) in good occlusion (RROC 2 and OKM grade C), 17.9% in incomplete occlusion (RROC 3a or OKM grade B), and no aneurysms in invalid occlusion (RROC 3b and OKM grade A). A total of 112 patients with 117 aneurysms received angiographic follow-up (mean 11.4 months), and the degree of occlusion showed a significant improvement (Z = 3.900, p < 0.001). The complete occlusion rate increased to 84.6% (99/117), while good and incomplete occlusion decreased to 6.8% (8/117) and 8.6% (10/117), respectively. A total of 14 cases (10.5%) presented narrowing of the parent artery, and nine cases (6.8%) had injured side branches. Cerebral hemorrhage occurred in four patients (3.0%), and symptomatic ischemic infarction occurred in six patients (4.5%). The final permanent morbidity (mCS ≥3) and mortality were 2.8% (3/133) and 0.8% (1/133), respectively. For 82 aneurysms treated by stent-assisted with coiling (SAC), large-sized, ruptured aneurysms (χ² = 7.767, p = 0.005) occurred. For 63 aneurysms treated by LEO stent monotherapy (LSM), multiple aneurysms, fusiform aneurysms (χ² = 18.958, p < 0.01), and/or small-sized aneurysms (Z = −2.692, p = 0.007) occurred.

Conclusions

Leo stents are safe and effective for aneurysms located in the posterior and distal anterior circulations. The overall degree of occlusion improved during a follow-up because of the FD effect of Leo stents. Aneurysms in these areas should be treated with personalized measures.