Treatment of Middle Cerebral Artery Aneurysms with Flow-Diverter Stents: A Systematic Review and Meta-Analysis

Quantitative Analysis of Hemodynamic Changes in Branch Arteries Covered by Flow Diverters

BACKGROUND AND OBJECTIVES

Understanding post-treatment hemodynamic alterations and their association with the patency of covered branch arteries is limited. This study aims to identify hemodynamic changes after flow diverter stenting and investigate their correlation with the patency status of covered branch arteries.

METHODS

All patients treated with pipeline embolization device for anterior cerebral artery aneurysms at our center between 2016 and 2020 were screened for inclusion. Quantitative digital subtraction angiography was used to analyze changes in hemodynamic parameters pre- and post-stenting. The patency status of covered branch arteries after stenting was categorized as either patent or flow impairment (defined as artery stenosis or occlusion).

RESULTS

A total of 71 patients, encompassing 89 covered branch arteries, were enrolled. Flow impairment was observed in 11.2% (10/89) of the branches. The mean transit time and full width at half maximum (FWHM) in covered branches were significantly prolonged post-stenting (P = .004 and .023, respectively). Flow-impaired branch arteries exhibited hemodynamic shifts contrary to those in patent branch arteries. Specifically, flow-impaired branches showed marked reductions in time to peak, FWHM, and mean transit time (decreases of 32.8%, 32.6%, and 29%, respectively; P = .006, .002, and .002, respectively). Further multivariate analysis revealed that reductions in FWHM in the branches (odds ratio = 0.97, 95% CI: 0.95-0.99, P = .007) and smoking (odds ratio = 14.5, 95% CI: 1.39-151.76, P = .026) were independent predictors of flow impairment of covered branches.

CONCLUSION

Pipeline embolization device stenting can cause a reduction in blood flow in branch arteries. Compared with patent branches, flow-impaired branches exhibit an increase in blood flow velocity after stenting. Smoking and ΔFWHM in the covered branches indicate flow impairment.

Stent plus balloon-assisted coiling with low-profile braided stents in the treatment of complex wide-necked intracranial bifurcation aneurysms

INTRODUCTION

Wide-necked bifurcation aneurysms pose significant challenges for endovascular treatment. A recent innovation, the stent plus balloon-assisted coiling technique, combines a stent and a balloon to address these aneurysms effectively.

PURPOSE

To evaluate the safety and efficacy of the stent plus balloon-assisted coiling for the treatment of wide-necked bifurcation aneurysms.

METHODS

We conducted a retrospective review of our endovascular database to identify patients who were treated with this technique and had a satisfactory angiographic follow-up of at least 24 months. Technical success, initial clinical and angiographic outcomes, procedural complications, and follow-up results were analyzed. Angiographic and clinical outcomes were assessed using Modified Raymond-Roy Classification and Modified Rankin Scale, respectively.

RESULTS

Our study included 37 aneurysms in 36 patients (26 females) with a mean age of 56.6 years. Mean aneurysm and neck sizes were 7.3 ± 3.5 mm and 3.7 ± 1.0 mm, respectively. Technical success reached 97.2%, with an immediate occlusion rate of 65.7%. At a mean follow-up of 36.5 ± 9.7 months, final angiographic follow-up showed a 91.9% complete occlusion rate. Three aneurysms did not achieve complete occlusion; however, none required retreatment. Complications developed in 32.4% of the procedures. Mortality and morbidity rates were 5.4% and 2.7%, respectively. A good clinical outcome was observed in 91.9% of patients.

CONCLUSION

Our results showed that stent plus balloon-assisted coiling technique allows good angiographic outcomes for wide-necked bifurcation aneurysms. However, overall complication rate is high. Subgroup analysis indicated promising safety and efficacy for MCA bifurcation aneurysms, suggesting this technique could be a valuable option for select aneurysms.

Pipeline embolization of complex, wide-necked middle cerebral artery bifurcation aneurysms: A single-center experience

PURPOSE

To evaluate the performance of Pipeline Embolization Device (PED) in complex, wide-necked middle cerebral artery (MCA) bifurcation aneurysms.

METHODS

We performed a retrospective review of patients treated with PED for complex, wide-necked MCA bifurcation aneurysms between August 2016 and March 2021. In addition to demographic data, we collected aneurysmal neck width, dome-to-neck ratio, complications, and clinical and angiographic follow-up. The embolization degree of aneurysms was evaluated by O'Kelly-Marotta (OKM) grading scale, and the prognosis was assessed with the modified Rankin Scale (mRS).

RESULTS

From August 2016 to March 2021, a total of 46 patients with 49 MCA bifurcation aneurysms in our center were enrolled, of whom all received PEDs successfully. The O'Kelly-Marotta (OKM) grading showed that post-procedure 15 patients (32.6%) were grade C, another 8 patients (17.4%) were grade D. Aneurysms with small remnant or complete occlusion were 50%, symptomatic ischemic events occurred in 3 (6.5%), and bleeding events in 1 (2.2%). 41 patients underwent a 6-month angiography follow-up, in which 7 patients (17.1%) remained OKM grade C and 30 patients (73.2%) achieved OKM grade D. Complete occlusion and small remnant aneurysms were up to 90.3%. 40 (97.6%) patients' mRS scores were 0, and 1 (2.4%) patient was 2. No new bleeding and ischemic events occurred during the 6-month.

CONCLUSIONS

The Pipeline Embolization Device provides a safe and effective treatment alternative for complex, wide-necked MCA aneurysms. A larger number with longer-term follow-up data is needed for further verification.

Current research status and future of endovascular treatment for basilar artery aneurysms

Aneurysms occurring along the basilar artery (BA) account for <1% of all intracranial aneurysms. Endovascular treatment (EVT) in particular is recommended for large unruptured BA aneurysms and ruptured BA aneurysms. Given that EVT techniques vary, a detailed review of EVT for BA aneurysms is necessary. In this review, the following issues were discussed: the anatomy and anomalies of the BA, the classification of BA aneurysms, the natural history of BA aneurysms, the status of open surgery, the use of EVT for various types of BA aneurysms and the deployment of new devices. According to the findings of this review and based on our experience in treating BA aneurysms, traditional coiling EVT is still the optimal therapy for most BA aneurysms. However, in some BA aneurysms, flow diverter (FD) deployment can be used. In addition, there are also some new devices, such as intrasaccular flow disruptors and stent-like devices that can be used to treat BA aneurysms. In general, EVT can yield good clinical and angiographic outcomes for patients with BA aneurysms. In addition, recent new devices and techniques, such as new-generation FDs generated via surface modification and virtual reality simulation techniques, show promise for EVT for BA aneurysms. These devices and techniques may further improve EVT outcomes for BA aneurysms.

Efficacy and safety of low profile stents in Y-stent assisted coil embolization of wide-necked bifurcation aneurysms: a systematic review and meta-analysis

Low-profile stents may provide significant advantages in Y-stent-assisted coiling due to their miniaturized design and capability to be delivered through a 0.0165-inch microcatheter. We aim to investigate the safety and efficacy of using these newer versions of stents in Y-stent-assisted coiling for the treatment of wide-necked bifurcation aneurysms. We conducted a systematic review of the PubMed, Embase, Cochrane Library, and Web of Science databases up to September 2023, following the PRISMA guidelines. Eligible studies included  ≥ 5 patients with intracranial wide-necked bifurcation aneurysms treated with Y-stent-assisted coiling using low-profile stents, providing angiographic and clinical outcomes. Two authors independently handled the search and selection. Primary outcomes were immediate and follow-up aneurysm occlusion, procedure-related complications, aneurysm recanalization, and retreatment. Secondary outcomes included technical success, procedure-related morbidity, procedure-related mortality, procedure-related stroke, and in-stent stenosis at follow-up. We analyzed the data using random-effects meta-analysis. In total, 19 studies including 507 patients with 509 aneurysms were included. 95% of the treated aneurysms were managed using the crossing Y-configuration. Technical success rate was 99%. Immediate adequate aneurysm occlusion was 90%. Follow-up angiographies were available for 443 aneurysms. The mean angiographic follow-up duration was 15.6 ± 1.9 months. The rates for follow-up adequate aneurysm occlusion and complete occlusion were 98% and 89%, respectively. After a mean clinical follow-up of 15 ± 2.4 months, a good clinical outcome was observed in 98% of patients. Overall, procedure-related morbidity and mortality rates were 1.3%, and 0.4%, respectively. Low-profile stents in Y-stent-assisted coiling outperform previous stent versions in terms of safety, efficacy, and technical success rates.

Magnetic resonance perfusion imaging findings following flow diversion in patients with complex middle cerebral artery bifurcation aneurysms: a single-center analysis regarding the jailed cortical branches

BACKGROUND

Flow diverter (FD) devices provide a safe and effective treatment option especially for wide-necked intracranial aneurysms. One of the main concerns in patients treated with FD devices is patency of arterial branches jailed by the stent. However, there are no long-term data from magnetic resonance perfusion (MRP) studies regarding jailed branches. In this study we aimed to reveal the MRP findings in patients with jailed middle cerebral artery (MCA) cortical branches during long-term follow-up after flow diversion.

METHODS

Patients who underwent FD stent treatment for MCA aneurysms with a resulting jailed cortical branch were included. Follow-up clinical, angiographic, and MRP examination findings were recorded. Different MRP parameters were measured in the MCA territory regarding the jailed branches.

RESULTS

Eighteen patients treated endovascularly with flow diversion for a total of 20 MCA aneurysms were included. At angiographic follow-up (median 35 months, range 7-95 months) complete occlusion was observed in 13 (65%) aneurysms and partial occlusion was observed in 6 (30%). The mean transit time (MTT) prolongation, MTT ratio, time-to peak (TTP) prolongation, and TTP ratio were 1.34, 1.20, 1.18, and 1.06 s, respectively, when compared with the contralateral side in the MCA territory. MTT, TTP, and cerebral blood volume values of the patients showed statistically significant differences compared with the contralateral side (P<0.05).

CONCLUSIONS

Flow diversion treatment of complex bifurcation aneurysms can be effective and safe. MRP examination may reveal perfusion changes in the territory vascularized via a jailed branch, and these changes are rarely accompanied by clinical findings.

Flow diversion for unruptured fusiform aneurysms of the proximal middle cerebral artery

Background

Managing fusiform aneurysms of the proximal (M1) segment of the middle cerebral artery (MCA) is challenging due to difficulties in both surgical and endovascular treatment. In this study, we present our experience using flow diverter stents for managing unruptured M1 segment fusiform aneurysms.

Methods

We conducted a retrospective review of the database of our institution to identify all patients who underwent flow diversion treatment for unruptured M1 segment fusiform aneurysms. We collected data on patient demographics, aneurysm characteristics, complications, angiographic follow-up results, and clinical outcomes.

Results

A total of 10 patients (five male and five female patients) with 10 unruptured M1 segment fusiform aneurysms were included in the study. The average age of the patients was 48 years (range: 16-64 years); five patients had aneurysms smaller than 10 mm, four had aneurysms measuring between 10 and 25 mm, and one patient had an aneurysm larger than 25 mm. The successful deployment of flow-diverting stents was achieved in all cases. Procedure-related morbidity was observed in 10% of patients, but there were no deaths. All patients showed good outcomes (modified Rankin Scale score of 0-1); eight out of 10 patients had available follow-up angiography results with a mean follow-up period of 11.6 months (range: 6-24 months). Complete occlusion occurred in six out of eight reviewed cases (75%).

Conclusion

Our preliminary findings suggest that using flow diversion for treating unruptured fusiform aneurysms in the proximal MCA is feasible and safe, with a satisfactory rate of complete occlusion. However, further studies involving larger case series are needed to validate the durability and efficacy of this treatment approach.

Endovascular treatment of middle cerebral artery aneurysms: current status and future prospects

Middle cerebral artery (MCA) aneurysms are complex and widely distributed throughout the course of the MCA. Various types of aneurysms can occur in the MCA. Ruptured as well as unruptured MCA aneurysms may require treatment to avoid bleeding or rebleeding. Currently, clipping is regarded as the first-line choice for the treatment of MCA aneurysms. However, endovascular treatment (EVT) is emerging as an alternative treatment in selected cases. EVT techniques vary. Therefore, it is necessary to review EVT for MCA aneurysms. In this review, the following issues were discussed: MCA anatomy and anomalies, classifications of MCA aneurysms, the natural history of MCA aneurysms, EVT status and principle, deployments of traditional coiling techniques and flow diverters (FDs), and deployments and prospects of intrasaccular flow disruptors and stent-like devices. According to the review and our experience, traditional coiling EVT is still the preferred therapy for most MCA aneurysms. FD deployment can be used in selective MCA aneurysms. Parent artery occlusion (PAO) can be used to treat distal MCA aneurysms. In addition, new devices can be used to treat MCA aneurysms, such as intrasaccular flow disruptors and stent-like devices. In general, EVT is gaining popularity as an alternative treatment option; however, there is still a lack of evidence regarding EVT, and longer-term data are not currently available for most EVT devices.

Stent assisted coil embolization for a dissecting cerebral aneurysm of middle cerebral artery: A case report and the literature review

Background

Dissecting aneurysms of the middle cerebral artery (MCA) are very rare. We herein report a case of an unruptured dissecting aneurysm of the MCA treated by stent-assisted coil embolization.

Case Description

A 65-year-old man with no history of trauma presented with a headache. Time-of-flight imaging revealed a dissecting cerebral aneurysm in the right M1 segment of the MCA, and the aneurysm had increased in size within a short time. We treated the aneurysm by endovascular stenting with coils, and the patient developed no neurological deficits.

Conclusion

Because of the potential involvement of the lenticulostriate artery (LSA) in the area of dissection, choosing the best treatment (such as direct surgery or endovascular treatment) may be challenging. Treatment efficacy depends on whether the LSA is affected and on the length of the dissection. In our case, the dissection did not involve the LSA and could therefore be treated by stent-assisted coil embolization.

Safety and efficacy of braided stents as stent monotherapy for the treatment of small intracranial aneurysms

BACKGROUND

The safety and efficacy of low-profile braided stent as stent monotherapy require further investigation.

OBJECTIVE

To analyze patient outcomes after treatment with braided stents used as "light" flow diverters.

MATERIAL/METHODS

Retrospective study to evaluate the occlusion rate of aneurysms treated with braided stent and remodeling of covered side branches and perforators. Several factors potentially influencing aneurysm occlusion were analyzed.

RESULTS

Thirty-five aneurysms in 31 patients were included. Six aneurysms (17.1%) had an acute subarachnoid hemorrhage. Braided stent was used as retreatment among 9 previously coiled aneurysms (25.7%). A total occlusion was achieved in 18 aneurysms (51.4%), entry remnant in 3 aneurysms (8.6%), incomplete filling in 6 aneurysms (17.1%) and complete filling in 8 aneurysms (22.9%). None of the aneurysms ruptured during the follow-up period. Of 32 stents deployed, we observed 3 cases (9.4%) of asymptomatic mild stenosis and 3 cases (10.7%) of narrowing of covered branches among 28 covered arteries. There were no cases of perforator infarction and no mortality or permanent morbidity associated with the treatment. Moreover, aneurysms <2.5 mm, aneurysms with a neck <1.8 mm, those with a mean aspect-ratio of 1.4, and lateral wall aneurysms had a higher frequency of adequate occlusion.

CONCLUSION

Braided stents used as stent monotherapy appear to be sufficiently effective in the treatment of very small intracranial aneurysms, despite a lower overall occlusion rate compared to a standard flow diversion strategy. However, given the low morbidity rate, this strategy may be an alternative to flow-diverter stents for small and distally located lesions.

Dome Resection and End-to-End Reanastomosis for a Middle Cerebral Artery Fusiform Aneurysm of the M1 Segment: 2-Dimensional Operative Video

Fusiform aneurysms of the middle cerebral artery (MCA) are both relatively uncommon and challenging to treat given their pathophysiology, morphology, and anatomy (e.g., perforating arteries involvement).1,2 Endovascular treatment of fusiform MCA aneurysms can achieve good outcomes in well-selected cases.3,4 Open microsurgical strategies are effective in a case of fusiform MCA aneurysms with complex anatomy or perforator involvement.2,5,6 We demonstrate the bypass strategy for resection of a fusiform M1 MCA aneurysm (Video 1). A 48-year-old female was referred for the treatment of a growing incidental right M1 MCA fusiform aneurysm. Imaging showed a tortuous M1 segment with no apparent perforator involvement, which we considered a candidate for resection and reanastomosis. A modified minipterional transsylvian approach was performed as described earlier.7,8 A double superficial temporal artery to middle cerebral artery bypass was performed to maintain flow to MCA territory and distal perforators in anticipation of a long temporary flow arrest due to complex aneurysmal dissection and reanastomosis and also to serve as long-term protective insurance. Resection and end-to-end reanastomosis will preserve the antegrade flow and prevent the risk stump thrombosis carried by a simple trapping.9,10 We cover the nuances of this technique including key steps to an efficient aneurysmal resection and complication avoidance. The patient tolerated the procedure well, and postoperative imaging showed no aneurysmal remnant and flow restoration with no evidence of stroke. We discharged the patient home with a modified Rankin scale of 0. The patient consented to the procedure and publication of his or her image.

High-Flow Bypass and Clip Trapping of a Giant Fusiform Middle Cerebral Artery (M1) Aneurysm: Technical Case Instruction

BACKGROUND AND IMPORTANCE

Giant intracranial aneurysms have a poor natural history with mortality rates of 68% and 80% over 2-year and 5-year, respectively. Cerebral revascularization can provide flow preservation while treating complex aneurysms requiring parent artery sacrifice. In this report, we describe the microsurgical clip trapping and high-flow bypass revascularization for a giant middle cerebral artery (MCA) aneurysm.

CLINICAL PRESENTATION

A 19-year-old man was diagnosed with a giant left MCA aneurysm after he suffered a left hemispheric capsular stroke 6 months ago. Since then, the patient recovered from the right hemiparesis and dysarthria with residual symptoms. Neuroimaging demonstrated a giant fusiform aneurysm encompassing the entire M1 segment. The bilobed aneurysm measured 37 × 16 × 15 mm. Endovascular treatment options included partial coiling of the aneurysm followed by deployment of flow-diverting stent spanning from the M2 branch-through the aneurysm neck-into the internal carotid artery. Because of the high risk of lenticulostriate artery stroke with endovascular treatment, the patient opted for microsurgical clip trapping and bypass. The patient consented to the procedure. High-flow bypass from internal carotid artery to M2 MCA was performed using radial artery graft, followed by aneurysm clip trapping using 3 clips.

CONCLUSION

We demonstrate the successful microsurgical treatment for a complex case of giant M1 MCA aneurysm with fusiform morphology. High-flow revascularization using radial artery graft helped in achieving good clinical outcome with complete aneurysm occlusion with flow preservation despite the challenging morphology and location. Cerebral bypass continues to be a useful tool to tackle complex intracranial aneurysms.

Distal stenting technique for coil embolization of early branch aneurysms of middle cerebral artery

BACKGROUND AND PURPOSE

Stent-assisted coil embolization of early branch aneurysms of the middle cerebral artery (MCA) can sometimes be challenging due to the small diameter and acute angle of the branches. This study aimed to analyze the treatment results and report the feasibility and outcomes of the distal stenting technique for these aneurysms.

MATERIALS AND METHODS

The distal stenting technique was used for 15 wide-neck MCA aneurysms (females, 10; males, 5; mean age, 65.1 years) originating from the early branch between December 2018 and October 2021. The average sizes of the dome, depth, and neck of the aneurysms were 4.17 mm (range: 2.99-6.21 mm), 2.86 mm (range: 1.82-3.72 mm), and 3.42 mm (range: 2.44-4.32 mm), respectively.

RESULTS

The average diameter of the stents was 4.0 mm (3.0 mm, 3; 4.0 mm, 6; 4.5 mm, 6). Stents were successfully deployed in all 15 aneurysms (100%). The average length of the procedure was 69 min (range: 45-117 min). On postoperative angiography, nine (60.0%) aneurysms were completely occluded, four (26.7%) had neck remnants, and two (13.3%) had contrast flow in the sac. During the procedure, vasospasm and thrombus formation occurred in one case each, but no neurological sequelae were observed. On follow-up digital subtraction angiography of the 10 aneurysms after an average of 13.7 months (range: 12-18 months), the branches were well preserved, and neck remnants were noted in four aneurysms (40.0%). No thromboembolic events occurred during the clinical follow-up.

CONCLUSION

The distal stenting technique using an open-cell stent can be a good option for coil embolization of early branch MCA aneurysms.

Two year follow-up of distal unruptured intracranial aneurysms treated with a surface modified flow diverter under prasugrel monotherapy

BACKGROUND

A new generation of modified surface flow diverters (FDs) and monotherapy using new antiplatelets may reduce both ischemic and hemorrhagic complications during the treatment of intracranial aneurysms. Previous preliminary safety analysis of distal unruptured intracranial aneurysms treated with the FD p48 MW HPC (phenox-Wallaby, Bochum, Germany) under antiplatelet monotherapy with prasugrel showed promising results. However, the long term outcomes of distal intracranial aneurysms treated with FDs under antiplatelet monotherapy are not known.

METHODS

This was a single center, prospective, pivotal, open single arm study. The primary (safety) endpoint was absence of any new neurological deficits after treatment until the 24 month follow-up. The primary (efficacy) endpoint was the incidence of complete aneurysm occlusion 24 months after treatment. The secondary (efficacy) endpoints were any incidence of aneurysm dome reduction 24 months after treatment.

RESULTS

21 patients harboring 27 distal aneurysms of the anterior circulation were included. No patient had neurologic deficits in the time from treatment to the 24 month follow-up. Complete aneurysm occlusion occurred in 20 (74%) of 27 aneurysms at the 24 month follow-up. Four aneurysms (14.8%) had dome reduction, and three aneurysms (11.1%) remained unchanged.

CONCLUSIONS

In this pilot trial, treatment of distal unruptured intracranial aneurysms with an FD under monotherapy with prasugrel, followed by monotherapy with aspirin, appeared to be safe and effective. Randomized studies with long term follow-up are needed to confirm these results.

Active drug-coated flow diverter in a preclinical model of intracranial stenting

BACKGROUND

Flow diverters carry the risk of thromboembolic complications (TEC). We tested a coating with covalently bound heparin that activates antithrombin to address TEC by locally downregulating the coagulation cascade. We hypothesized that the neuroimaging evidence of TEC would be reduced by the coating.

METHODS

16 dogs were implanted with overlapping flow diverters in the basilar artery, separated into two groups: heparin-coated (n=9) and uncoated (n=7). Following implantation, high-frequency optical coherence tomography (HF-OCT) was acquired to quantify acute thrombus (AT) formation on the flow diverters. MRI was performed postoperatively and repeated at 1, 2, 3, 4, and 8 weeks, consisting of T1-weighted imaging, time-0f-flight (ToF), diffusion weighted imaging (DWI), susceptibility weighted imaging (SWI), and fluid attenuated inversion recovery (FLAIR) sequences. Neurological examinations were performed throughout the 8-week duration of the study.

RESULTS

The mean AT volume on coated devices was lower than uncoated (0.014 vs 0.018 mm³); however, this was not significant (P=0.3). The mean number of foci of magnetic susceptibility artifacts (MSAs) on SWI was significantly different between the uncoated and coated groups at the 1-week follow-up (P<0.02), and remained statistically different throughout the duration of the study. The AT volume showed a direct linear correlation with the MSA count and 80% of the variance in the MSA could be explained by the AT volume (P<0.001). Pathological analysis showed evidence of ischemic injury at locations of MSA.

CONCLUSIONS

Heparin-coated flow diverters significantly reduced the number of new MSAs after 1 week follow-up, showing the potential to reduce TEC.

Silk + flow-diverter stent for the treatment of intracranial aneurysms associated with balloon angioplasty: A retrospective study

Background

The silk + flow-diverter stent is increasingly used to treat complex intracranial aneurysms including wide-neck and fusiform aneurysms. Balloon angioplasty has been used to better appose the flow diverter (FD) to the vessel wall and, thus, improve aneurysm occlusion rates and decrease periprocedural complications. Sparse data are available concerning the results of this technique. We report our experience with silk + FD associated with balloon angioplasty for the treatment of intracranial aneurysms.

Methods

A retrospective study was conducted on all patients treated by the silk + FD. Clinical charts, procedural data, and angiographic results were reviewed and compared between those treated with balloon angioplasty. A multivariate analysis was conducted to identify predictors of complications, occlusion, and outcome.

Results

Between July 2014 and May 2016, we identified 209 patients with 223 intracranial aneurysms. There were 176 (84.2%) women and 33 (15.8%) men. The most common stent size used was 4.5 mm in 101 patients (46.1%), followed by 4 mm in 57 patients (26%). Univariate analysis observed that stent diameter was significantly related to aneurysm occlusion (P < 0.05). Patients with more than 1 aneurysm treated with silk + stent have a 9.07 times greater chance of having complications in the procedure than patients with only 01 aneurysm (OR = 9.07; P = 0.0008). Patients who had angioplasty without the use of a balloon have a 13.69-times-higher risk of complications (OR = 13.69; P = 0.0003). Older age, larger aneurysms, and the use of more than 1 FD device were predictors of recanalization.

Conclusion

Endovascular treatment of intracranial aneurysms with the silk + FD associated with balloon angioplasty is a safe and effective therapeutic option. Balloon angioplasty in combination with FD lowers the risk of complications. Higher complication rates and worse outcomes are associated with older age and large aneurysms.

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.

Safety and efficacy of flow diverter stents in the treatment of middle cerebral artery aneurysms: a single-center experience and follow-up data

PURPOSE

This study aims to evaluate the safety and efficacy of flow diverters (FDs) in the treatment of middle cerebral artery (MCA) aneurysms and share the follow-up (F/U) results.

METHODS

The treatment and F/U results of 76 MCA aneurysms treated with the flow re-direction endoluminal device (FRED), FRED Jr., and pipeline embolization device (PED) FD stents were evaluated retrospectively. The aneurysm occlusion rates were compared between FDs, and the integrated and jailed branches were evaluated through follow-ups. The oversizing of the stent was compared between occluded/non-occluded aneurysms and integrated branches.

RESULTS

The mean F/U duration was 32 ± 6.3 months, and the mean aneurysm diameter was 4.45 mm. A total of 61 (80.3%) aneurysms were wide-necked; 73 (96.1%) were saccular; 52 (68.4%) were located at the M1 segment; and 36 (45.6%) FREDs, 23 (29.1%) FRED Jr.s, and 19 (24.1%) PEDs were used for treatment. The overall occlusion rates for the 6-, 12-, 24-, 36-, and 60-month digital subtraction angiographies were 43.8%, 63.5%, 73.3%, 85.7%, and 87.5% respectively. The last F/U occlusion rates were 67.6% for FRED, 66.7% for PED, and 60.6% for FRED Jr. (P = 0.863). An integrated branch was covered with an FD during the treatment of 63 (82.8%) aneurysms. A total of six (10%) of the integrated branches were occluded without any symptoms at the last F/U appointment. The median oversizing was 0.45 (0-1.30) for occluded aneurysms, and 0.50 (0-1.40) for non-occluded aneurysms (P = 0.323). The median oversizing was 0.70 (0.45-1.10) in occluded integrated branches and 0.50 (0-1.40) in non-occluded branches (P = 0.131). In-stent stenosis was seen in 22 (30.1%) of the stents at the 6-month F/U and in only 2 (4.7%) at the 24-month F/U. Thus, none of the patients had any neurological deficits because of the in-stent stenosis. Severe in-stent stenosis was seen in two stents.

CONCLUSION

MCA aneurysms tend to be complex, with integrated branches and potentially wide necks. FD stents are safe and effective in the treatment of MCA aneurysms, and the patency of the side and jailed branches is preserved in most cases. Higher occlusion and lower in-stent stenosis rates are seen with longer F/U durations.

Case Report: Tubridge flow diverter for a ruptured fusiform aneurysm of the M1 segments of the middle cerebral artery

We report a case of the middle cerebral artery (MCA) M1 segment ruptured fusiform aneurysm that was successfully treated using a domestic Tubridge flow diverter (TFD). A 40-year-old man was admitted to the hospital because of a headache and was diagnosed with subarachnoid hemorrhage. Cerebral angiography revealed a ruptured fusiform aneurysm in the M1 segment of the right MCA. TFD, combined with coil embolization, was used for perioperative treatment. No obvious complications were observed. Follow-up digital subtraction angiography 2 and 12 months after the surgery showed that the aneurysm was occluded, and the patient recovered well. This is the first known case of this treatment with this type of stent in such an aneurysm and demonstrates that TFD can be used to treat ruptured fusiform aneurysms in the M1 segment of the MCA.

Surgical or Endovascular Treatment of MCA Aneurysms: An Agreement Study

BACKGROUND AND PURPOSE

MCA aneurysms are still commonly clipped surgically despite the recent development of a number of endovascular tools and techniques. We measured clinical uncertainty by studying the reliability of decisions made for patients with middle cerebral artery (MCA) aneurysms.

MATERIALS AND METHODS

A portfolio of 60 MCA aneurysms was presented to surgical and endovascular specialists who were asked whether they considered surgery or endovascular treatment to be an option, whether they would consider recruitment of the patient in a randomized trial, and whether they would provide their final management recommendation. Agreement was studied using κ statistics. Intrarater reliability was assessed with the same, permuted portfolio of cases of MCA aneurysm sent to the same specialists 1 month later.

RESULTS

Surgical management was the preferred option for neurosurgeons (n = 844/1320; [64%] responses/22 raters), while endovascular treatment was more commonly chosen by interventional neuroradiologists (1149/1500 [76.6%] responses/25 raters). Interrater agreement was only "slight" for all cases and all judges (κ = 0.094; 95% CI, 0.068-0.130). Agreement was no better within specialties or with more experience. On delayed requestioning, 11 of 35 raters (31%) disagreed with themselves on at least 20% of cases. Surgical management and endovascular treatment were always judged to be a treatment option, for all patients. Trial participation was offered to patients 65% of the time.

CONCLUSIONS

Individual clinicians did not agree regarding the best management of patients with MCA aneurysms. A randomized trial comparing endovascular with surgical management of patients with MCA aneurysms is in order.

Treatment of unruptured middle cerebral artery aneurysms: Systematic review in an attempt to perform a network meta-analysis

Objective

Open surgical clipping has been generally considered the best treatment option for unruptured middle cerebral artery aneurysms (uMCAAs). However, this type of aneurysm is being treated endovascularly with the appearance of new devices. We have carried out a systematic review of randomized and quasi-experimental studies to conduct a network meta-analysis (NMA) to assess the safety and efficacy of the different treatment methods currently used in uMCAAs.

Methods

The literature was searched by using PubMed and Google Scholar databases. Eligibility criteria were randomized or quasi-experimental studies including at least five cases per arm and reporting duration of follow-up and number of lost cases. The end points were: angiographic success, final neurological outcome, and the need for retreatments.

Results

We could only analyze four quasi-experimental studies with 398 uMCAAs. All of them compared clipping vs. coiling. Clipping showed better results than coiling in all analyzed end points. We could not conduct the proposed NMA because of the absence of randomized or quasi-experimental studies. Instead, a systematic review is further discussed.

Conclusions

There is an urgent need for comparative studies on the treatment of uMCAAs.

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.

Comparative study of on-label versus off-label treatment of intracranial aneurysms with the Pipeline embolization device

OBJECTIVE

The Pipeline embolization device (PED) is widely used for the treatment of intracranial aneurysms, including in off-label applications. In this work, the authors compared the real-world efficacy and safety of PED use in on-label and off-label aneurysm treatments.

METHODS

Clinical and angiographic data of patients who underwent PED placement at a high-volume academic medical center were retrospectively obtained. Treatments were classified as on-label if they fell within the applications approved by the United States Food and Drug Administration as of 2021. Recorded outcomes included aneurysm occlusion, procedural complications, ischemic events, in-stent stenosis, intracranial hemorrhage, postprocedural functional status, and death.

RESULTS

In total, 416 aneurysms in 330 patients were treated with PED, comprising 256 aneurysms that received on-label treatments and 160 that received off-label treatments. The overall rate of complete aneurysm occlusion was 76.4% for on-label aneurysms and 75.6% for off-label aneurysms (p = 0.898). The risk of ischemic stroke in patients who underwent off-label treatments was 15.2%, which was higher than the 4.2% rate in patients who underwent on-label treatment (p = 0.003). All other clinical complications, procedural complications, and long-term functional status were comparable between the on-label and off-label groups.

CONCLUSIONS

In real-world practice, off-label use of PED is common and can achieve similar efficacy as on-label use. However, in aggregate, off-label use was found to carry an increased rate of ischemic complications. With judicious attention to safety and individual patient characteristics, these results highlight the scale and general feasibility of off-label PED use by experts.

A Single Flow Re-direction Endoluminal Device for the Treatment of Large and Giant Anterior Circulation Intracranial Aneurysms

PURPOSE

The purpose of this study was to report the author's experiences in treating large (10-25 mm) and giant (>25 mm) intracranial aneurysms (IAs) using a single Flow Re-direction Endoluminal Device (FRED) without assistant coiling, with a focus on procedure-related complications.

MATERIALS AND METHODS

A total of 33 patients who were treated with FRED between January 2018 and July 2020 were retrospectively reviewed. The timing of procedure-related complications was chronologically categorized as acute (within 7 days), subacute (8 to 21 days), and delayed (after 21 days) periods. Follow-up angiography was performed at 2 to 27 months (mean 9.7 months), and clinical follow-up was performed at 1 to 31 months (mean 14.1 months) in all patients.

RESULTS

Six (18.2%) patients experienced procedure-related complications, including 2 (6.1%) in acute period, 1 (3.0%) in subacute period, and 3 (9.1%) in delayed period. Thromboembolic complications occurred in 5 (15.2%) patients and hemorrhagic complications in 1 (3.0%). Permanent morbidity and mortality rates were 3.0% each. Non-internal carotid artery (ICA) location of IAs (odds ratio 6.532; 95% confidence interval, 1.335-17.816; p=0.034) was the only independent risk factor for procedure-related complications on multivariate logistic regression analysis.

CONCLUSION

The procedure-related complication rate was 18.2% in this study. Procedure-related complications might increase when treating large and giant IAs located on a non-ICA, especially on the middle cerebral artery. Therefore, it may be suggested that neurointerventionists and endovascular neurosurgeons should pay attention to the location of IAs when treating large and giant IAs with a single FRED.

Staged Hybrid Techniques With Straightforward Bypass Surgery Followed by Flow Diverter Deployment for Complex Recurrent Middle Cerebral Artery Aneurysms

Background

Recurrent complex middle cerebral artery (MCA) aneurysms after combined clipping and endovascular surgery are challenging, and if conventional techniques are adapted, advanced surgical, endovascular, and a combination of both techniques are often required. For such complex aneurysms, safe and effective straightforward techniques for all neurovascular surgeons are warranted. We describe the details of staged hybrid techniques with straightforward bypass surgery followed by flow diverter deployment in a patient with complex MCA aneurysm.

Illustrative Case

A 69-year-old woman presented with left recurrent large MCA aneurysm enlargement 25 years after direct surgery and coil embolization for ruptured aneurysm. The recurrent MCA aneurysm had large and complex morphology and was adhering to the brain tissues. Therefore, it was unsuitable to treat such aneurysm with conventional surgical and endovascular techniques with a high risk of morbidity. We performed (1) M2 ligation following superficial temporal artery-M2 bypass and (2) flow diverter deployment assisted with coil packing in two sessions. Three months after the second session, the aneurysm was completely occluded with endothelialization of the neck. Angiographic findings revealed no recurrence 12 months after the treatment.

Conclusions

Staged hybrid techniques with straightforward bypass surgery followed by flow diverter deployment may be a safe and effective treatment for complex recurrent MCA aneurysms.

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.

Comprehensive review of the recent advances in devices for endovascular treatment of complex brain aneurysms

The International Subarachnoid Aneurysm Trial (ISAT) showed superiority for endovascular treatment of ruptured aneurysms and technology has since moved on rapidly. Many approaches and technology now exist for the endovascular management of ruptured and unruptured intracranial aneurysms, which reflects their varied nature - there is no one-size-fits-all technique. We aim to provide an overview of the various classes of device and the major developments over the past decade. Coiling is the oldest of the technology and continues to demonstrate high levels of occlusion and acceptable risks, making it the default treatment choice, particularly in the acutely ruptured aneurysm setting. Advances on coiling include the use of adjuncts such as balloons, stents and fully retrievable temporary neck-bridging devices, which have facilitated the treatment of more complex aneurysms. Flow divertors have also revolutionised complex aneurysm treatment with small added risk in acute aneurysm treatment and seek to remodel the aneurysm-vessel interface without accessing the aneurysm sac. The latest development and most promising avenue appears to be intrasaccular flow disrupting devices like WEB, Contour and Neqstent that provide excellent opportunities to treat wide neck complex aneurysm with minimal mortality and morbidity and good occlusion rates and may in future replace a significant number of stent-assisted coiling too.

Middle Cerebral Artery Aneurysm Trial (MCAAT): A randomized care trial comparing surgical and endovascular management of MCA aneurysm patients

BACKGROUND

Whether the best management of middle cerebral artery (MCA) aneurysm patients is surgical or endovascular remains uncertain, with little evidence to guide decision-making. A randomized care trial offering MCA aneurysm patients a 50% chance of surgical and a 50% chance of endovascular management may optimize outcomes in the presence of uncertainty.

METHODS

The Middle Cerebral Artery Aneurysm Trial (MCAAT) is an investigator-initiated, multi-center, parallel group, prospective, 1:1 randomized controlled clinical trial. All adult patients with MCA aneurysms, ruptured or unruptured, amenable to surgical and endovascular treatment can be included. The composite primary outcome is 'Treatment Success': i) occlusion or exclusion of the aneurysm using the allocated treatment modality; ii) no intracranial hemorrhage during follow-up; iii) no retreatment of the target aneurysm during follow-up, iv) no residual aneurysm on angiographic follow-up and v) independence (mRS <3) at 1 year. The trial tests two versions of the same hypothesis (one for ruptured and one for unruptured MCA aneurysm patients): Surgical management will lead to a 15% absolute increase in the proportion of patients reaching Treatment Success from 55% to 70% (ruptured) or from 75% to 90% (unruptured aneurysm patients) compared to endovascular treatment (any method). In this pragmatic trial, outcome evaluations are by treating physicians, except for 1 year angiographic results which will be core lab assessed. The trial will be monitored by an independent data safety monitoring committee to assure safety of participants. MCAAT is registered at clinicaltrials.gov: NCT05161377.

CONCLUSION

Patients with MCA aneurysms can be optimally managed within a care trial protocol.

Pipeline embolization of MCA aneurysms in the M2-M4 segment: Dual center study and meta-analysis

OBJECTIVE

Flow diversion of distal MCA aneurysms in the M2-M4 segments with Pipeline embolization device is promising, but further study is needed. Here, we seek to quantify the safety and efficacy of Pipeline embolization in the M2-M4 region in a dual-center cohort and comprehensive meta-analysis.

METHODS

Clinical and angiographic data of eligible patients was obtained from participating centers. A systematic review was performed with searches of Pubmed, Scopus, Embase, and the Cochrane Library for articles from inception to May 2021. 86 studies were identified in systematic review. Of these, 7 studies with 46 aneurysms met the inclusion criteria and were aggregated with 8 aneurysms from our dual-center cohort for analysis.

RESULTS

In our dual-center cohort, complete occlusion was observed in 88% (7/8) of aneurysms, and no patients experienced hemorrhagic or thromboembolic complications. Clinical outcomes were reported for 100% (54/54) of aneurysms included in meta-analysis and angiographic follow-up was available for 91% (49/54). The overall rate of complete aneurysm occlusion was 80% (95% CI, 69-91%), and the overall rate of clinical complication was 9% (95% CI, 2-16%).

CONCLUSION

Pipeline embolization of cerebral aneurysms of the M2-M4 segments of the MCA was reasonably effective and safe in a small group of selected patients, but further study is needed to validate these preliminary results.

Endovascular management of middle cerebral artery aneurysms (single-center case series study)

Background

Middle cerebral artery (MCA) aneurysms were usually subjected to treatment by surgery, while endovascular treatment (EVT) was performed only in chosen patients. We assessed the efficacy, safety, and durability in addition to the clinical outcome of EVT when it is regarded as the first-line treatment modality for MCA aneurysms.

Results

We recruited 30 patients with MCA aneurysms who underwent definitive management from July 2017 to July 2018. All those patients were treated endovascularly; 22 patients (73.3%) presented with subarachnoid hemorrhage, and 8 patients (26.7%) had different presentations, including isolated headaches and seizures. EVT was performed for all patients and required the use of a balloon, stent, or double catheter techniques in 13 cases and flow diverter stents alone in two cases. Clinical outcome was assessed by the modified Rankin Scale (mRS) at 3 months. Angiographic follow-up was done by a conventional angiography at 6 months and after 1 year. EVT was efficiently conducted, leading to an outstanding accomplishment (mRS = 1–2) in 29 patients. However, one patient had a thromboembolic complication, followed by death after severe chest infection that was not related to the procedure. Immediate anatomical results included complete aneurysmal occlusion with the establishment of normal cerebral circulation. Angiographic follow-up revealed 24 unchanged occlusions and 5 cases with recanalization that required further treatment.

Conclusion

EVT of MCA aneurysms is a viable treatment option with positive outcomes in most cases. Nevertheless, the employment of long-term imaging follow-up is compulsory for validating such early results, often with respect to anatomical and functional stability.

Flow Diversion for Middle Cerebral Artery Aneurysms: An International Cohort Study

BACKGROUND

Open surgery has traditionally been preferred for the management of bifurcation middle cerebral artery (MCA) aneurysms. Flow diverting stents present a novel endovascular strategy for aneurysm treatment.

OBJECTIVE

To add to the limited literature describing the outcomes and complications in the use of flow diverters for the treatment of these complex aneurysms.

METHODS

This is a multicenter retrospective review of MCA bifurcation aneurysms undergoing flow diversion. We assessed post-treatment radiological outcomes and both thromboembolic and hemorrhagic complications.

RESULTS

We reviewed the outcomes of 54 aneurysms treated with flow diversion. Four (7.4%) of the aneurysms had a history of rupture (3 remote and 1 acute). Fourteen (25.9%) of the aneurysms already underwent either open surgery or coiling prior to flow diversion. A total of 36 out of the 45 aneurysms (80%) with available follow-up data had adequate aneurysm occlusion with a median follow-up time of 12 mo. There were no hemorrhagic complications but 16.7% (9/54) had thromboembolic complications.

CONCLUSION

Flow diverting stents may be a viable option for the endovascular treatment of complex bifurcation MCA aneurysms. However, compared to published series on the open surgical treatment of this subset of aneurysms, flow diversion has inferior outcomes and are associated with a higher rate of complications.

Standalone Flow Diversion Therapy Effectively Controls Rebleeding of Acutely Ruptured Internal Carotid Artery Trunk (Nonbranching) Microaneurysms

Flow diversion is a promising option in selected patients with acutely ruptured microaneurysms. In this article, we reviewed our experience. Patients with acute spontaneous subarachnoid hemorrhage (SAH) after rupture of a blister-like or saccular microaneurysm (≤2 mm maximal diameter) at a nonbranching ICA site treated from January 2016 to June 2019 using flow diversion as standalone therapy were included in this study. An EVD was usually placed preventively. Antiplatelet effects of pre-procedure DAPT were evaluated (target PRU, 80–160). After the intervention, DAPT was continued for ≥6 months, aspirin—indefinitely. Angiographic controls were obtained. Fifteen patients (12 female; mean age, 46.4 years) with 15 ruptured ICA microaneurysms (mean diameter, 1.8 mm) were included. An EVD was placed in 12 patients (75%) before DAPT administration and stenting. PRU values immediately before FDS were 1–134 (mean, 72.1). One patient died 27 days after flow diversion due to a suspected fulminant pulmonary embolism. Aneurysms were completely occluded at the 6–12-month angiographic follow-up in 14/14 surviving patients, with no rebleeding at a mean of 14 months. Late mRS was 0–2 in 13/14 patients and 3 in one due to sequelae of the original hemorrhage. Flow diversion provided robust aneurysm rebleeding control. Angiographic follow-up confirmed complete aneurysm occlusion in all the cases.

Safety and Efficacy of the FRED Jr Flow Re-Direction Endoluminal Device for Intracranial Aneurysms: Retrospective Multicenter Experience With Emphasis on Midterm Results

Background and Purpose: Flow diversion is increasingly used as an endovascular treatment for intracranial aneurysms. In this retrospective multicenter study, we analyzed the safety and efficacy of the treatment of intracranial, unruptured, or previously treated but recanalized aneurysms using Flow Re-Direction Endoluminal Device (FRED) Jr with emphasis on midterm results.

Materials and Methods: Clinical and radiological records of 150 patients harboring 159 aneurysms treated with FRED Jr at six centers between October 2014 and February 2020 were reviewed and consecutively included. Clinical outcome was measured by using the modified Rankin Scale (mRS). Anatomical results were assessed according to the O'Kelly-Marotta (OKM) scale and the Cekirge-Saatci Classification (CSC) scale.

Results: The overall complication rate was 24/159 (16%). Thrombotic-ischemic events occurred in 18/159 treatments (11%). These resulted in long-term neurological sequelae in two patients (1%) with worsening from pre-treatment mRS 0–2 and mRS 4 after treatment. Complete or near-complete occlusion of the treated aneurysm according to the OKM scale was reached in 54% (85/158) at 6-month, in 68% (90/133) at 1-year, and in 83% (77/93) at 2-year follow-up, respectively. The rates of narrowing or occlusion of a vessel branch originating from the treated aneurysm according to the CSC scale were 11% (12/108) at 6-month, 20% (17/87) at 1-year, and 23% (13/57) at 2-year follow-up, respectively, with all cases being asymptomatic.

Conclusions: In this retrospective multicenter study, FRED Jr was safe and effective in the midterm occlusion of cerebral aneurysms. Most importantly, it was associated with a high rate of good clinical outcome.

Giant Middle Cerebral Artery Aneurysms: A 55-Patient Series

BACKGROUND

The treatment of middle cerebral artery (MCA) giant aneurysms (GAs) represents a challenging task.

METHODS

The data for 55 patients treated for MCA GA (≥25 mm) at the N.N. Burdenko NMRCN between 2010 and 2019 were analyZed.

RESULTS

The GAs were located in the M1 segment in 11 (20%) patients, MCA bifurcation in 33 (60%), M2 in 7 (12.7%), and M3 in 4 (7.3%). There were 32 (58.2%) saccular and 23 (41.8%) fusiform GAs. MCA GAs were treated with neck clipping (50.9%), clipping with the artery lumen formation (3.6%), bypass surgeries (34.5%), wrapping (3.6%), and endovascular surgery (7.3%). A worsening of the neurologic state in the perioperative period was observed in 50.9% of patients. The complete closure of GA was achieved in 78.2%. Surgery-related mortality was 1.8%. The long-term outcome was favorable in 76.9% of patients. Surgery-related and disease-related plus treatment failures-related mortality was 9.6%.

CONCLUSIONS

Microsurgical clipping and bypass surgery are the main operative interventions for MCA GA treatment. These operations are technically complex and are followed by a relatively high percentage of complications. The main tasks that require further investigations are the introduction of new precise diagnostic methods for the collateral circulation assessment in the cortical MCA branches, the perfection of the algorithm for the bypass selection, and investigation of the long-term results of the endovascular and combined treatments. It is of major importance to thoroughly observe the patients long-term after the surgery and ensure the possibility for further angiographic studies.

Multi-centric European post-market follow-up study of the Neuroform Atlas Stent System: primary results

BACKGROUND

Few prospective series have described the safety and effectiveness of the Neuroform Atlas Stent System. We aimed to investigate the efficacy and safety of the device in patients treated for unruptured aneurysm.

METHODS

ATLAS EU PMCF is a consecutive, prospective, multicentric study that included patients with unruptured saccular aneurysm of all sizes. Follow-up visits were scheduled at 3-6 months and 12-16 months with digital subtraction angiography (DSA) or MRI imaging follow-up as per the site standard of care. The primary efficacy endpoint was adequate aneurysm occlusion (Raymond Roy occlusion grade I and II) on 12 month angiography. The primary safety endpoint was any major stroke or ipsilateral stroke or neurological death within 12 months.

RESULTS

Of the 106 patients consented, 105 were treated with at least one Neuroform Atlas stent. There was a failed implantation attempt in 1 patient, 85 patients received lateral stenting, and 19 patients received Y-stenting. Mean aneurysm neck size was 4.2 mm (range 1.9-33 mm). Adequate occlusion was observed in 95.1% immediately after the procedure and in 98.9% of cases at 1 year DSA follow-up. Overall, 1.0% (1/102; 95% CI 0.0% to 5.3%) of patients experienced a primary safety endpoint of major stroke. Three minor strokes resulted in a modified Rankin Scale score of 2.

CONCLUSIONS

In this multicentric, prospective study, stent-assisted coiling of medium size unruptured aneurysms with the Neuroform Atlas stent resulted in a favorable rate of satisfactory occlusion. In our findings, the use of the Y-stenting technique was associated with increased rates of procedural complications.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02783339.

"Shelf" Technique Using a Novel Braided Self-Expandable Stent for the Treatment of Wide-Necked Bifurcation Aneurysms

Background

Different endovascular techniques exist for treatment of cerebral wide-necked bifurcation aneurysms (WNBA). We present the “shelf” technique with the novel woven LVIS EVO stent, which enables forming a buttress at the level of the aneurysm neck to prevent coil prolapse and additional stenting.

Methods

Single-center retrospective analysis of patients treated with the “shelf” technique by using LVIS EVO stent in incidental WNBAs between January 2020 and March 2021. Inclusion criteria were saccular aneurysms with neck width ≥4 mm or a dome/neck ratio ≤2. Primary endpoint was a favorable navigation to the target vessel and successful deployment of the LVIS EVO stent with forming a buttress that enables aneurysm occlusion by subsequent coiling. Secondary endpoints were aneurysm occlusion on follow-up, procedure-related complications and clinical outcome.

Results

A total of 15 patients were included. The primary end point was reached in 100% of cases. A complete aneurysm occlusion at the end of the procedure was achieved in 14/15 patients (93%). No intraprocedural complications occurred. All patients except one were discharged with an modified Rankin Scale (mRS) of 0. Procedure-related morbidity was 7%. Median follow-up imaging was 115 days (7–419 days) and available for 11/15 (73%) of the patients. Of those, 10 (91%) individuals had a complete aneurysm occlusion and 1 showed a residual neck. In all patients, the covered branch was patent and no ischemic complications occurred during follow-up.

Conclusion

This study demonstrates the “shelf” technique with LVIS EVO stents as a feasible and safe treatment option for WNBAs with very good short-term occlusion rates.

Early clinical experience with the p48MW HPC and p64MW HPC flow diverters in the anterior circulation aneurysm using single anti-platelet treatment

Background

The p64MW HPC and p48MW HPC flow diverters have reduced thrombogenicity due to hydrophilic coating. The purpose of this study was to evaluate its safety and efficacy in Mongolian patients under single antiplatelet therapy (SAPT) with prasugrel.

Materials and methods

We performed a retrospective review of patients enrolled into our prospectively maintained database to identify all patients treated with either the p48MW HPC or p64MW HPC under SAPT. We recorded baseline demographics, aneurysm size and location, procedural complications, angiographic and clinical results.

Results

24 patients, (female = 21, 87.5%), age 48.2 ± 11.6 years (range 25–63) underwent treatment of 30 aneurysms with either p64MW HPC or p48MW HPC. All aneurysms were saccular with dome width 8.2 ± 6.5 (range 1.6–26.0 mm) and dome height 7.6 ± 6.7 (range 1.6–30.0 mm). None of the aneurysms were previously treated. The average PRU was 54.6 ± 31.2 (range 1–127) on pre-operative VerifyNow testing. Angiographic follow-up was available for 13 patients (17 aneurysms), 183 ± 36 days post-procedure, at which point 64.7% of aneurysms (n = 11/17) were completely occluded and 11.8% (n = 2/17) had only neck remnants resulting in 76.5% of aneurysms being adequately occluded A single intra-operative complication (4.2%) occurred however all patients were mRS ≤1 at last follow-up. There were two post-operative complications neither of which resulted in permanent neurological morbidity. There were no instances of post-operative aneurysmal rupture or delayed parenchymal haemorrhage. The overall mortality was 0%.

Conclusion

The efficacy and safety of p64MW HPC coated devices under SAPT is similar to uncoated flow diverters that require DAPT.

Safety, Efficacy, and Durability of Stent Plus Balloon-Assisted Coiling for the Treatment of Wide-Necked Intracranial Bifurcation Aneurysms

BACKGROUND

Wide-necked bifurcation aneurysms remain a challenge for endovascular surgeons. Dual-stent-assisted coiling techniques have been defined to treat bifurcation aneurysms with a complex neck morphology. However, there are still concerns about the safety of dual-stenting procedures. Stent plus balloon-assisted coiling is a recently described endovascular technique that enables the coiling of wide-necked complex bifurcation aneurysms by implanting only a single stent.

OBJECTIVE

To investigate the feasibility, efficacy, safety, and durability of this technique for the treatment of wide-necked bifurcation aneurysms.

METHODS

A retrospective review was performed of patients with wide-necked intracranial bifurcation aneurysms treated with stent plus balloon-assisted coiling. The initial and follow-up clinical and angiographic outcomes were assessed. Preprocedural and follow-up clinical statuses were assessed using modified Rankin scale.

RESULTS

A total of 61 patients (mean age: 54.6 ± 10.4 yr) were included in the study. The immediate postprocedural digital subtraction angiography revealed complete aneurysm occlusion in 86.9% of the cases. A periprocedural complication developed in 11.5% of the cases. We observed a delayed ischemic complication in 4.9%. There was no mortality in this study. The permanent morbidity rate was 3.3%. The follow-up angiography was performed in 55 of 61 patients (90.1%) (the mean follow-up period was 25.5 ± 27.3 mo). The rate of complete aneurysm occlusion at the final angiographic follow-up was 89.1%. The retreatment rate was 1.8%.

CONCLUSION

The results of this study showed that stent plus balloon-assisted coiling is a feasible, effective, and relatively safe endovascular technique for the treatment of wide-necked bifurcation aneurysms located in the posterior and anterior circulation.

In Situ Side-to-Side Pericallosal-Pericallosal Artery and Callosomarginal-Callosomarginal Artery Bypasses for Complex Distal Anterior Cerebral Artery Aneurysms: A Technical Note

BACKGROUND

Despite surgical and endovascular technical improvements over the last decades, the treatment of complex aneurysms of the distal anterior cerebral artery (ACA) is very challenging for both vascular neurosurgeons and interventional neuroradiologists. Furthermore, the interpersonal anatomic variability requires, most of the time, a tailored planning.

OBJECTIVE

To describe a novel technique of bypasses in the territory of ACA to protect the brain territory distal to the aneurysm.

METHODS

A 53-yr-old male with a large complex fusiform aneurysm of the left distal A2 segment of the ACA, involving the origin of the callosomarginal and pericallosal arteries, was judged not suitable for a single procedure (endovascular or neurosurgical). Two side-to-side bypasses were performed in a single surgery to connect the pericallosal and callosomarginal arteries of both sides, distally to the aneurysm. Subsequently, an endovascular embolization of the aneurysm was achieved with coils.

RESULTS

The patency of the microanastomoses, performed in the anterior interhemispheric fissure, was positively evaluated intraoperatively with indocyanine green and fluorescein videoangiography. The aneurysm sac, together with proximal A2 segment, was completely occluded with platinum coils. At the last follow-up, computed tomography angiography confirmed the patency of both bypasses, without any sign of aneurysm recanalization. The patients never complained of any focal neurological deficits or worsening of clinical status.

CONCLUSION

We present an elegant and innovative solution to completely protect the distal ACA territory in cases of complex aneurysm involving the origin of both callosomarginal and pericallosal arteries.

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.

Analytical methods for braided stents design and comparison with FEA

Braiding technology is nowadays commonly adopted to build stent-like devices. Indeed, these endoprostheses, thanks to their typical great flexibility and kinking resistance, find several applications in mini-invasive treatments, involving but not limiting to the cardiovascular field. The design process usually involves many efforts and long trial and error processes before identifying the best combination of manufacturing parameters. This paper aims to provide analytical tools to support the design and optimization phases: the developed equations, based on few geometrical parameters commonly used for describing braided stents and material stiffness, are easily implementable in a worksheet and allow predicting the radial rigidity of braided stents, also involving complex features such as multiple twists and looped ends, and the diameter variation range. Finite element simulations, previously validated with respect to experimental tests, were used as a comparator to prove the reliability of the analytical results. The illustrated tools can assess the impact of each selected parameter modification and are intended to guide the optimal selection of geometrical and mechanical stent proprieties to obtain the desired radial rigidity, deliverability (minimum diameter), and, if forming processes are planned to modify the shape of the stent, the required diameter variations (maximum and minimum diameters).

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.

Surgical or Endovascular Management of Middle Cerebral Artery Aneurysms: A Randomized Comparison

OBJECTIVE

There are few randomized data comparing clipping and coiling for middle cerebral artery (MCA) aneurysms. We analyzed results from patients with MCA aneurysms enrolled in the CURES (Collaborative UnRuptured Endovascular vs. Surgery) and ISAT-2 (International Subarachnoid Aneurysm Trial II) randomized trials.

METHODS

Both trials are investigator-led parallel-group 1:1 randomized studies. CURES includes patients with 3-mm to 25-mm unruptured intracranial aneurysms (UIAs), and ISAT-2 includes patients with ruptured aneurysms (RA) for whom uncertainty remains after ISAT. The primary outcome measure of CURES is treatment failure: 1) failure to treat the aneurysm, 2) intracranial hemorrhage during follow-up, or 3) residual aneurysm at 1 year. The primary outcome of ISAT-2 is death or dependency (modified Rankin Scale score >2) at 1 year. One-year angiographic outcomes are systematically recorded.

RESULTS

There were 100 unruptured and 71 ruptured MCA aneurysms. In CURES, 90 patients with UIA have been treated and 10 await treatment. Surgical and endovascular management of unruptured MCA aneurysms led to treatment failure in 3/42 (7%; 95% confidence interval [CI], 0.02-0.19) for clipping and 13/48 (27%; 95% CI, 0.17-0.41) for coiling (P = 0.025). All 71 patients with RA have been treated. In ISAT-2, patients with ruptured MCA aneurysms managed surgically had died or were dependent (modified Rankin Scale score >2) in 7/38 (18%; 95% CI, 0.09-0.33) cases, and 8/33 (24%; 95% CI, 0.13-0.41) for endovascular. One-year imaging results were available in 80 patients with UIA and 62 with RA. Complete aneurysm occlusion was found in 30/40 (75%; 95% CI, 0.60-0.86) patients with UIA allocated clipping, and 14/40 (35%; 95% CI, 0.22-0.50) patients with UIA allocated coiling. Complete aneurysm occlusion was found in 24/34 (71%; 95% CI, 0.54-0.83) patients with RA allocated clipping, and 15/28 (54%; 95% CI, 0.36-0.70) patients with RA allocated coiling.

CONCLUSIONS

Randomized data from 2 trials show that better efficacy may be obtained with surgical management of patients with MCA aneurysms.

Torsional Characterization of Braided Flow Diverter Stents : A New Method to Evaluate Twisting Phenomenon

PURPOSE

In the interventional treatment of cerebral aneurysms, flow diverter (FD) stents have played a significant role for more than a decade. Many studies have shown good aneurysm occlusion rates and low complication profiles. However, feared complications include acute thrombotic vessel occlusion due to stenotic deformation of the FD during release, the so-called twisting. This work investigates the behavior of different stent types to causative torsion forces in a mechanical model.

MATERIALS AND METHODS

Torsion characterization equipment was custom built, and two different FD stents (Derivo, Acandis and P64, Phenox) with n = 3 were tested. One end of the FD was fixed while the other end was twisted while measuring the torsion force.

RESULTS

In torsional force vs. the twisting angle graph, a very sharp decrease and increase in force was recorded when the stent collapsed or reopened, respectively, making it possible to characterize for twisting. All six devices showed partial/complete collapse on torsion and showed significant delayed reopening on untwisting. Interestingly on repeated testing, the stent collapsed at earlier angles, probably due to microscopic material defects. Slight variations between stents of the same type suggest that more extensive data sets are needed.

CONCLUSIONS

We report a new method to characterize torsion for braided FD stents, which is reliable and reproducible. Additionally, the delayed reopening and the tendency to collapse at earlier angles on consequent testing maneuvers can be significant for clinical usage.

Expanding Indications for Flow Diverters: Distal Aneurysms, Bifurcation Aneurysms, Small Aneurysms, Previously Coiled Aneurysms and Clipped Aneurysms, and Carotid Cavernous Fistulas

Flow diverter devices have gained wide acceptance for the treatment of unruptured intracranial aneurysms. Most studies are based on the treatment of large aneurysms harboring on the carotid syphon. However, during the last years the “off-label” use of these stents has widely grown up even if not supported by randomized studies. This review examines the relevant literature concerning “off-label” indications for flow diverter devices, such as for distal aneurysms, bifurcation aneurysms, small aneurysms, recurrent aneurysms, and direct carotid cavernous fistulas.

Longitudinal Monitoring of Flow-Diverting Stent Tissue Coverage After Implant in a Bifurcation Model Using Neurovascular High-Frequency Optical Coherence Tomography

BACKGROUND

Tissue growth over covered branches is a leading cause of delayed thrombotic complications after flow-diverter stenting (FDS). Due to insufficient resolution, no imaging modality is clinically available to monitor this phenomenon.

OBJECTIVE

To evaluate high-frequency optical coherence tomography (HF-OCT), a novel intravascular imaging modality designed for the cerebrovascular anatomy with a resolution approaching 10 microns, to monitor tissue growth over FDS in an arterial bifurcation model.

METHODS

FDS were deployed in a rabbit model (n = 6), covering the aortic bifurcation. The animals were divided in different groups, receiving dual antiplatelet therapy (DAPT) (n = 4), aspirin only (n = 1), and no treatment (n = 1). HF-OCT data were obtained in vivo at 3 different time points in each animal. For each cross-sectional image, metal and tissue coverage of the jailed ostium was quantified. Scanning electron microscopy images of harvested arteries were subsequently obtained.

RESULTS

Good quality HF-OCT data sets were successfully acquired at implant and follow-up. A median value of 41 (range 21-55) cross-sectional images were analyzed per ostium for each time point. Between 0 and 30 d after implant, HF-OCT analysis showed a significantly higher ostium coverage when DAPT was not given. After 30 d, similar growth rates were found in the DAPT and in the aspirin group. At 60 d, a coverage of 90% was reached in all groups.

CONCLUSION

HF-OCT enables an accurate visualization of tissue growth over time on FDS struts. The use of FDS in bifurcation locations may induce a drastic reduction of the jailed-branch ostium area.

Surgical Management of Complex Middle Cerebral Artery Aneurysms: An Institutional Review

Background:

Complex middle cerebral artery (MCA) aneurysms are defined as large (≥10 mm) or giant (≥25 mm) aneurysms with M2 branches arising from the aneurysm rather than M1 segments and usually require some form of reconstruction of the bifurcation. Their management is difficult and surgery is preferred over endovascular modalities because of their peculiar angioarchitecture and association with critical branch points or perforators.

Objectives:

The study was aimed at analyzing surgically managed complex MCA aneurysms and discussing characteristics not favorable for endovascular management, surgical nuances and clipping strategies, patient outcomes, and newer diagnostic modalities which help improve management.

Methods:

Nine cases of surgically operated complex MCA aneurysms were identified from January 2017 to July 2019. The aneurysm characteristics, surgical nuances, clipping strategies, patient outcomes and points not favoring endovascular management were tabulated and analyzed.

Results:

The mean maximum aneurysm diameter was 13.4 mm and the mean fundus/neck ratio was 1.6. The average microscope time was 124 min, and the most common method was clip reconstruction. The average number of clips used was 2.7 and the mean follow-up was 13 months. All patients have good postoperative outcome (Modified Rankin Score 0-2). The complete occlusion rate was 88.9% with one intraoperative voluntary residual sac which was coated. Computational fluid dynamic study results done preoperatively correlated with intraoperative findings.

Conclusions:

MCA aneurysms pose a significant challenge for endovascular treatment because of various factors such as luminal thrombi, complex angio-architecture, precarious branch/perforator locations, broad necks, and fusiform characteristics. Surgical management in experienced hands can tackle all these problems with an armamentarium of clipping techniques and bypass procedures.