Preliminary Experience of the Surpass Streamline Flow Diverter for Large and Giant Unruptured Internal Carotid Artery Aneurysms

Surpass Streamline Flow Diverter for the Treatment of Craniocervical Unruptured Dissecting Aneurysms: A Multi-Institutional Retrospective Study

OBJECTIVE

Currently, there is no established treatment consensus for craniocervical unruptured dissecting aneurysms (UDAs). This study aimed to assess the safety and efficacy of the Surpass Streamline Flow Diverter (SSFD) for treating craniocervical UDAs.

METHODS

A retrospective review of 3 centers' databases was conducted to identify patients with craniocervical UDAs treated with SSFDs from January 2021 to December 2023. Data, including patient and aneurysm characteristics, procedure details, imaging findings, and follow-up data were analyzed.

RESULTS

The study included 35 patients with 35 craniocervical UDAs. The mean maximal length of the UDAs was 13.0 ± 6.0 mm, with 57% ranging from 10 to 25 mm. At a mean follow-up of 8.7 ± 2.5 months, the complete occlusion rate was 71% (25/35), with no recurrences detected. Perioperative complications occurred in 3 patients (9%), comprising ischemic stroke in 2 patients (6%) and hemorrhagic stroke in 1 patient (3%). All patients had a good clinical outcome at the 6-month follow-up (modified Rankin Scale <3). Multivariate logistic regression analysis revealed that aneurysmal dilation with stenosis (odds ratio = 0.034, 95% confidence interval: 0.001-0.845; P = 0.04) was a significant predictive factor for incomplete occlusion of treated aneurysms.

CONCLUSIONS

Our findings suggest that SSFD is a safe and effective tool for craniocervical UDAs, demonstrating a high occlusion rate, acceptable complication rate, and good clinical outcome.

Long-term results and neuropathy of internal carotid artery aneurysms treated with high-flow bypass using saphenous vein graft and parent artery occlusion

OBJECTIVES

Giant internal carotid artery aneurysms require treatment owing to the risk of rupture, cranial nerve palsy in the cavernous sinus, and optic nerve symptoms. Among treatment options for internal carotid artery aneurysms, we compared the results of flow diverter stent with those of high-flow bypass.

MATERIALS AND METHODS

A total of 45 consecutive patients with large or giant internal carotid artery aneurysms underwent high-flow bypass using saphenous vein graft and double assist superficial temporal artery-middle cerebral artery bypass and proximal ligation of the internal carotid artery at the neck.

RESULTS

The high-flow bypass patency rate was 96 %. Among the target aneurysms, 78 % and 96 % thrombosed within one and three years postoperatively, respectively. Neurological symptoms associated with aneurysms improved in 69 % of patients. The complication rate was 4 %. The thrombosis rate of aneurysms treated with high-flow bypass tended to be higher and faster than those treated with flow diverter stent.

CONCLUSIONS

Even in the era of flow diverter stenting, treatment with high-flow bypass should be considered for patients who have difficulty with flow diverter stent implantation or without thromboses. Therefore, the treatment of cerebral aneurysms with high-flow bypass requires high safety and efficacy.

Treatment strategies and outcomes for intracranial fusiform aneurysms: A systematic review and meta-analysis

BACKGROUND

Fusiform aneurysms are a distinct subgroup of intracranial aneurysms with unique characteristics and pose a treatment challenge compared to common saccular aneurysms. Traditionally, surgery was the main treatment; however, endovascular techniques are gaining favor.

METHODS

We searched major databases for studies on treatment, clinical outcomes, and radiological outcomes of intracranial fusiform aneurysms published before May 31st, 2023 in order to compare surgical Vs endovascular treatment strategies. Pooled data analysis was performed using a random-effects model.

RESULTS

This systematic review and meta-analysis analyzed 1704 patients with 1737 fusiform aneurysms from 63 studies. Endovascular treatment, particularly stent-assisted coiling and stenting, emerged as the preferred approach with lower mortality and complication rates compared to surgery. Aneurysm location played a role in outcomes, with anterior circulation aneurysms generally faring better. Deconstructive strategies, designed to occlude the parent artery, carried a doubled risk of complications compared to reconstructive approaches, which aim to preserve blood flow (OR: 2.188; 95% CI: 1.474-3.248; p < 0.001).

CONCLUSION

Endovascular techniques are becoming the mainstay of treatment for fusiform aneurysms, offering improved safety and efficacy compared to surgery. Anterior circulation location and reconstructive strategies are associated with better outcomes. However, no significant differences in OR for early complete occlusion were found between surgery and endovascular techniques at discharge and follow-up with very low heterogeneity among studies.

Systematic Review and Meta-Analysis of Endovascular Therapy Effectiveness for Unruptured Saccular Intracranial Aneurysms

Background

Currently, endovascular treatment of intracranial aneurysms (ICAs) is limited by low complete occlusion rates. The advent of novel endovascular technology has expanded the applicability of endovascular therapy; however, the superiority of novel embolic devices over the traditional Guglielmi detachable coils (GDCs) is still debated. We performed a systematic review of literature that reported Raymond-Roy occlusion classification (RROC) rates of modern endovascular devices to determine their immediate and follow-up occlusion effectiveness for the treatment of unruptured saccular ICAs.

Methods

A search was conducted using electronic databases (PUBMED, Cochrane, ClinicalTrials.gov, Web of Science). We retrieved studies published between 2000-2022 reporting immediate and follow-up RROC rates of subjects treated with different endovascular ICA therapies. We extracted demographic information of the treated patients and their reported angiographic RROC rates.

Results

A total of 80 studies from 15 countries were included for data extraction. RROC rates determined from angiogram were obtained for 21,331 patients (72.5% females, pooled mean age: 58.2 (95% CI: 56.8-59.6), harboring 22,791 aneurysms. The most frequent aneurysm locations were the internal carotid artery (46.4%, 95% CI: 41.9%-50.9%), the anterior communicating artery (26.4%, 95% CI: 22.5%-30.8%), the middle cerebral artery (24.5%, 95% CI:19.2%-30.8%) and the basilar tip (14.4%, 95% CI:11.3%-18.3%). The complete occlusion probability (RROC-I) was analyzed for GDCs, the Woven EndoBridge (WEB), and flow diverters. The RROC-I rate was the highest in balloon-assisted coiling (73.9%, 95% CI: 65.0%-81.2%) and the lowest in the WEB (27.8%, 95% CI:13.2%-49.2%). The follow-up RROC-I probability was homogenous in all analyzed devices.

Conclusions

We observed that the coil-based endovascular therapy provides acceptable rates of complete occlusion, and these rates are improved in balloon-assisted coils. Out of the analyzed devices, the WEB exhibited the shortest time to achieve >90% probability of follow-up complete occlusion (~18 months). Overall, the GDCs remain the gold standard for endovascular treatment of unruptured saccular aneurysms.

A Review of Current Flow Diverters

Flow diverter (FD) devices are new-generation stents placed in the parent artery at the aneurysmal neck to obstruct intra-aneurysmal blood flow, thus favoring intra-aneurysmal thrombosis. In Japan, about eight years have passed since health insurance approval was granted for FD devices, and FD placement to treat aneurysms has become widespread. Treatment indications have also been expanded with the introduction of novel devices. At present, three types of FD (Pipeline, FRED, and Surpass Streamline) are available in Japan. This report represents a compilation of available FD technologies and describes the current consensus on this treatment.

Inflow Angle and Height-Width Ratio are Predictors of Incomplete Occlusion at One and Two Years After Flow Diverter Treatment for Small- and Medium-Sized Internal Carotid Artery Aneurysms

OBJECTIVE

We investigated the association between the inflow angle of aneurysms and their occlusion status at 1 and 2 years after flow diverter (FD) treatment.

METHODS

We retrospectively analyzed 42 consecutive patients from a single center with 43 untreated, unruptured internal carotid artery (ICA) proximal to communicating segment, saccular aneurysms sized <12 mm.

RESULTS

At 1 year posttreatment, the complete occlusion (CO) rate was 58.1%. On univariate analyses, the proportion of inflow angle >90° was significantly lower in the CO group than in the incomplete occlusion group (20.0% VS. 83.3%; P < 0.001). The CO incidence decreased with a height-width (H/W) ratio of <1.2 (P = 0.059). On multivariate analysis, an H/W ratio of <1.2 (odds ratio [OR], 0.076; P = 0.027) and an inflow angle of >90° (OR, 0.020; P = 0.0011) significantly influenced CO at 1 year post FD. At 2 years posttreatment, the CO rate was 76.3% (29/38 cases with available follow-up data). On univariate analyses, in the CO group compared to the incomplete occlusion group, the proportion of H/W ratio <1.2 was significantly lower (P = 0.005) and the proportion of inflow angle >90° was significantly lower (P = 0.021); aneurysm dome size tended to be larger (8.5 mm vs. 7.1 mm; P = 0.080). On multivariate analysis, an H/W ratio <1.2 (OR, 0.042; P = 0.015) and an inflow angle >90° (OR: 0.088; P = 0.031) significantly influenced CO at 2 years post FD.

CONCLUSIONS

The inflow angle of >90° and H/W ratio <1.2 may significantly influence the CO rate in small- or medium-sized internal carotid artery aneurysms 1 and 2 years post FD.