Hemodynamic Effects of Stent-Induced Straightening of Parent Artery vs. Stent Struts for Intracranial Bifurcation Aneurysms

Stand-alone small low-profile braided stents for challenging unruptured posterior inferior cerebellar artery aneurysms compared to conventional endovascular methods: A cohort study

ObjectivePosterior inferior cerebellar artery (PICA) aneurysms are uncommon and may be challenging to treat, especially if they are very small saccular or dissecting pseudoaneurysms at proximal and mid-PICA locations. They are usually technically difficult to treat with conventional reconstructive endovascular methods. We present our experience with PICA aneurysms treated by a stand-alone small, low-profile stent with a moderate flow-diverting effect (low-profile visualized intraluminal support junior (LVIS Jr)) compared to conventional endovascular methods.MethodsSingle institution cases of treated unruptured PICA aneurysms from 2015 to May 2022 were retrospectively reviewed. Patient characteristics, pre-and postoperative images, and last clinical and radiological outcomes were analyzed. Comparative statistical analysis was used.ResultsNine cases of unruptured PICA aneurysms treated with stand-alone LVIS Jr (group 1) and seven cases treated with other conventional methods (group 2) were identified. The mean age was 56 versus 61.43 years, sex was female in 7 versus 6 cases, and the left side was involved in 7 versus 4 cases in group 1 and group 2, respectively. All aneurysms were in the proximal PICA segment except for one case in the mid-PICA segment aneurysm in each group. There was a difference in aneurysm type in both groups (p = 0.008). All aneurysms were of saccular type except for five dissecting types in group 1 and 2 in group 2. The mean aneurysm size was 1.91 ± 0.62 in group 1 and 9.04 ± 5.82 mm in group 2 (p < 0.0002). In group 2, treatment was with PICA sacrifice (one case), primary aneurysm coiling (three cases), stent-assisted coiling (one case), and flow diverter (two cases). Complications were only puncture site-related that occurred once in each group. There were no differences in mean clinical or radiological follow-up. Aneurysm recurrence with retreatment occurred in two cases in each group. All patients had an mRS 0-2 at the last follow-up.ConclusionIn selected cases, unruptured small or dissecting PICA aneurysms may be treated safely and effectively using single stand-alone LVIS Jr. Prospective studies are needed to validate safety and efficacy.

Anterior circulation location-specific results for stent-assisted coiling - carotid versus distal aneurysms: 1-year outcomes from the Neuroform Atlas Stent Pivotal Trial

BACKGROUND

The Neuroform Atlas Stent System is an established treatment modality for unruptured anterior and posterior circulation intracranial aneurysms. Location-specific results are needed to guide treatment decision-making. However, it is unclear whether there are differences in safety and efficacy outcomes between carotid and more distal anterior circulation aneurysms.

METHODS

The ATLAS IDE trial was a prospective, multicenter, single-arm, open-label interventional study that evaluated the safety and efficacy of the Neuroform Atlas Stent System. We compared differences in efficacy and safety outcomes of proximal internal carotid artery (ICA) versus distal and bifurcation anterior circulation aneurysms.

RESULTS

Of 182 cases, there were 70 aneurysms in the ICA and 112 in the distal anterior circulation (including ICA terminus/bifurcation). There were no significant differences in the primary efficacy endpoint (85.5% vs 83.9%, p=0.78) and complete aneurysm occlusion rates (88.7% vs 87.9%, p=0.78) between proximal ICA aneurysms and distal aneurysms, respectively. Complications were more often encountered in distal and bifurcation aneurysms, but the overall rate of major safety events was low and comparable between the two groups (1.4% vs 6.3%, p=0.14). Recanalization and retreatment rates were also similar between the groups.

CONCLUSION

The results of this study suggest that the Neuroform Atlas Stent System is a safe and efficacious treatment modality for unruptured anterior circulation intracranial aneurysms, regardless of aneurysm location.

TRIAL REGISTRATION NUMBER

NCT02340585.

How does the recurrence-related morphology characteristics of the Pcom aneurysms correlated with hemodynamics?

Introduction

Posterior communicating artery (Pcom) aneurysm has unique morphological characteristics and a high recurrence risk after coil embolization. This study aimed to evaluate the relationship between the recurrence-related morphology characteristics and hemodynamics.

Method

A total of 20 patients with 22 Pcom aneurysms from 2019 to 2022 were retrospectively enrolled. The recurrence-related morphology parameters were measured. The hemodynamic parameters were simulated based on finite element analysis and computational fluid dynamics. The hemodynamic differences before and after treatment caused by different morphological features and the correlation between these parameters were analyzed.

Result

Significant greater postoperative inflow rate at the neck (Qinflow), relative Qinflow, inflow concentration index (ICI), and residual flow volume (RFV) were reported in the aneurysms with wide neck (>4 mm). Significant greater postoperative RFV were reported in the aneurysms with large size (>7 mm). Significant greater postoperative Qinflow, relative Qinflow, and ICI were reported in the aneurysms located on the larteral side of the curve. The bending angle of the internal carotid artery at the initiation of Pcom (αICA@PCOM) and neck diameter had moderate positive correlations with Qinflow, relative Qinflow, ICI, and RFV.

Conclusion

The morphological factors, including aneurysm size, neck diameter, and αICA@PCOM, are correlated with the recurrence-inducing hemodynamic characteristics even after fully packing. This provides a theoretical basis for evaluating the risk of aneurysm recurrence and a reference for selecting a surgical plan.

Enterprise Treatment for Recurrent Basilar Tip Aneurysm after PulseRider-assisted Coil Embolization: A Case Report

PulseRider (Cerenovus, Irvine, CA, USA) is a relatively novel device used for the treatment of wide-neck aneurysms with a coil-assisted effect. However, treatment options for recurrent aneurysms after PulseRider-assisted coil embolization remain controversial. Here we report a case of recurrent basilar tip aneurysm (BTA) treated with Enterprise 2 after PulseRider-assisted coil embolization. A woman in her 70s underwent coil embolization for a subarachnoid hemorrhage with ruptured BTA 16 years ago. Recurrence was detected at 6-year follow-up, and an additional coil embolization was performed. Nevertheless, gradual recurrence still occurred, and PulseRider-assisted coil embolization was performed without any complications 9 years after the second treatment. However, recurrence was detected once more at 6-month follow-up. Thus, stent-assisted coil embolization using Enterprise 2 (Cerenovus) through PulseRider was selected for angular remodeling. Enterprise 2 was deployed between the right P2 segment of the posterior cerebral artery (PCA) and basilar artery (BA) after an effective coil embolization, which achieved effective angular remodeling between the right PCA and BA. The patient's postoperative course was uneventful, and no recanalization was detected after half a year. Although PulseRider is effective for wide-neck aneurysm treatment, recurrence remains a possibility. Additional treatment using Enterprise 2 is safe and effective with the expectation of angular remodeling.

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.