Endovascular treatment of intracranial vertebrobasilar artery dissecting aneurysms: Parent artery occlusion versus flow diverter

Flow diverters in the treatment of intracranial dissecting aneurysms: a systematic review and meta-analysis of safety and efficacy

BACKGROUND

Intracranial dissecting aneurysms present clinical challenges, demanding immediate intervention due to their high bleeding risk. While traditional treatments have limitations, the potential of flow diverters shows promise but remains a subject of ongoing debate for optimal management. The aim of this study was assess the safety and efficacy of flow diverters in the treatment of intracranial dissecting aneurysms.

METHODS

A systematic review and meta-analysis was performed following established guidelines. The search encompassed PubMed, Scopus, Web of Science, and Embase databases up to July 20, 2023. Eligible studies reporting outcomes of interest were included, and relevant data were extracted and analyzed using R software.

RESULTS

The analysis, based on data pooled from 20 included studies involving 329 patients, revealed a favorable functional outcome rate of 89.7% at the last follow-up. The mortality rate during the follow-up period was 2.4%, decreasing to 0.9% when excluding the outlier study. In the final angiographic follow-up, a complete occlusion rate of 71.7% and an adequate occlusion rate of 88.3% were observed. Notably, studies with longer angiographic follow-up times exhibited lower rates of complete (P=0.02) and adequate (P<0.01) occlusion. A minimal aneurysm recurrence/rebleeding rate of 0.1% was noted, while in-stent stenosis/thrombosis occurred at a rate of 1.14%. Additionally, ischemic events/infarctions were seen in 3.3% of cases. The need for retreatment was minimal, with a rate of 0.9%, and the technical success rate was impressively high at 99.1%.

CONCLUSION

This study highlights the safety and efficacy of flow diverters in treating intracranial dissecting aneurysms. Further research, encompassing larger multicenter studies with extended follow-up periods, is crucial for comprehending occlusion dynamics, refining treatment strategies, improving long-term outcomes, and addressing methodological limitations.

Cerebral revascularization for complex vertebrobasilar artery dissecting aneurysms

Vertebrobasilar artery dissecting aneurysms (VBDAs) are the most surgically challenging type of aneurysm. Cerebral revascularization is the ultimate treatment for complex VBDAs. We retrospectively analysed the characteristics, surgical outcomes and follow-up data of 21 patients who underwent cerebral revascularization to treat complex VBDAs from 2015 to 2022. According to the location of the aneurysm and the anatomic relationship between the VBDA and the PICA, VBDA patients were classified into four groups: aneurysms located at the VA with PICA involvement (10 patients), aneurysms located at the VA without PICA involvement (1 patient), aneurysms located at the basilar apex segment (1 patient) and aneurysms located at the basilar trunk segment (9 patients). A surgical algorithm for complex VBDAs was determined primarily by the location of the aneurysm, the status of the aneurysm and the ability of retrograde blood flow to reach the proximal vertebrobasilar artery. Surgical modalities for patients with aneurysms in the VA with PICA involvement included low-flow (OA-PICA) bypasses with aneurysm trapping, aneurysm excision or reconstructive clip in 8 patients and STA-PCA bypass combined with PICA preservation and aneurysm trapping in 2 patients. In patients with aneurysms in the VA without PICA involvement, aneurysm excision was performed without cerebral bypass. In patients with aneurysms in the basilar apex segment, high-flow bypass (ECA-RA-P2) with aneurysm trapping was performed. In patients with aneurysms in the basilar trunk segment, surgical modalities included high-flow bypasses (ECA-RA-P2 and LVA-RA-P2) with aneurysm trapping or proximal occlusion in 6 patients, ECA-RA-P2 bypass with partial proximal occlusion in 1 patient, ECA-RA-P2 bypass alone in 1 patient, and STA-PCA bypass with R-VA narrowing in 1 patient. Of the 21 patients, 20 experienced clinical improvement or no change, and 17 of 21 patients achieved favourable functional outcomes (mRS ≤ 2). However, one patient died of infarction and respiratory failure postoperatively. Aneurysms were completely obliterated in 13 patients, shrank in 5 patients and stabilized in 2 patients. The median follow-up period was 32.5 months. During the follow-up period, all bypasses were patent, and further clinical improvement was observed in 11 patients. Cerebral revascularization appears to be safe and effective for the treatment of complex VBDAs, and cerebral revascularization could act as a complementary treatment strategy.

Fungal symptomatic intracranial aneurysm treated with a flow diverting stent: A case report

Background

Intracranial infectious aneurysms (IIAs) are very rare, and fungal aneurysms are infrequently reported. We report a case of an unruptured IIA caused by fungal rhinosinusitis and treated with a flow-diverting stent.

Case Description

An 81-year-old woman visited the ophthalmology department with impaired eye movement and ptosis and was placed under follow-up. A week later, she also developed a headache; magnetic resonance angiography revealed an aneurysm measuring 2 mm in the C4 portion of the right internal carotid artery. A 3-week follow-up with contrast-enhanced magnetic resonance imaging showed an increase in its size to 10 mm, and a contrast lesion was observed surrounding the right cavernous sinus. The patient started treatment with voriconazole and steroids on the same day. Ten weeks later, despite improvements in inflammation, the size of the aneurysm was unchanged; we, therefore, treated the aneurysm with a flow-diverting stent. Oculomotor nerve palsy improved, and the patient was discharged to a rehabilitation hospital 28 days after the placement, with a modified Rankin Scale of 4. A 1-year follow-up angiogram showed a partial decrease in the size of the aneurysm, with an O'Kelly-Marotta grading scale of B3.

Conclusion

IIAs grow rapidly, and the risk of rupture is high due to the weakening of the aneurysmal wall. To reduce the risks of rupture and recurrence after treatment, the infection should be treated before inserting a flow-diverting stent. Flow-diverting stent placement may be an effective treatment for IIA once the original infection has been cured.

Unruptured Intradural Posterior Circulation Dissecting/Fusiform Aneurysms Natural History and Treatment Outcome

BACKGROUND

The natural history and outcome of unruptured posterior circulation dissecting fusiform aneurysms is not fully understood. These have a high risk of morbidity and mortality, not only due to natural history but also due to the challenging and controversial treatment approaches currently available compared to other types of intracranial aneurysms.

METHODS

We performed a retrospective study of a prospectively collected aneurysm database at a quaternary neurovascular hospital. We included consecutive patients with unruptured intradural vertebrobasilar dissecting aneurysms between January 2000 and July 2016 who were followed to 2020. Description of baseline, procedural, and outcomes data was performed. Comparisons of patient who had aneurysm rupture on follow-up, increase in 2 or more points of mRS in follow-up and progression of the aneurysm was performed.

RESULTS

Seventy patients with 78 fusiform posterior circulation aneurysms were identified. Thirty-nine (55.7%) patients were male with a mean age of 51.7 years (SD ± 17.6). When multiple, aneurysms were more likely to be fusiform (60%) than saccular (40.0%). Baseline diameter (measured on CTA/MRA/DSA), length as well as symptomatic presentation were significantly higher in aneurysms which grew over time. Coronary disease, diabetes and growth were associated an >2 increase in mRS. Diabetes as well as initial symptomatic presentation were associated with rupture.

CONCLUSIONS

Unruptured dissecting/fusiform aneurysm are associated with a considerable rate of rupture during follow-up. Growth is associated with morbidity even in the absence of rupture. Initial large size, coronary disease, diabetes, and to a lesser extent female gender may merit closer follow-up and/or prophylactic treatment.

Conservative Therapy vs. Endovascular Approach for Intracranial Vertebrobasilar Artery Trunk Large Aneurysms: A Prospective Multicenter Cohort Study

Background

Intracranial vertebrobasilar trunk large (≥10 mm) aneurysms (IVBTLAs) are rare and challenging to manage. In this study, we describe the natural prognosis and evaluate the safety and efficacy of endovascular treatment of IVBTLAs compared with conservative therapy.

Methods

This prospective multicenter cohort study included patients with IVBTLAs, who chose either endovascular treatment (endovascular group) or conservative therapy (conservative group) after discussion with their doctors. The primary endpoint was the incidence of serious adverse events (SAEs) related to the target vessel, while secondary endpoints included target vessel-related mortality, major stroke, other serious adverse events, and aneurysm occlusion rate.

Results

In total, 258 patients were referred to our two centers for the management of vertebrobasilar aneurysms, and 69 patients had IVBTLAs. Among them, 51 patients underwent endovascular treatment, and 18 patients received conservative therapy. The incidence of target vessel-related SAEs was 15.7% (8/51) in the endovascular group and 44.4% (8/18) in the conservative group (P = 0.031). The target vessel-related mortality was 2.0% (1/51) in the endovascular group and 38.9% (7/18) in the conservative group (P < 0.001). The cumulative survival rates in the endovascular group and conservative group within 1-year, 3-year, and 5-year were 98.0% vs. 83.3%, P = 0.020; 98.0% vs. 66.7%, P = 0.001; and 98.0% vs. 35.6%, P < 0.001, respectively. Multivariate analysis revealed conservative therapy, giant aneurysm, and ischemic onset as risks factor for SAEs.

Conclusions

Compared with conservative treatment, endovascular treatment of the IVBTLAs may be associated with a lower incidence of SAEs, with higher 1-year, 3-year, and 5-year survival rates. Conservative therapy, giant aneurysm, and ischemic onset were associated with a high risk of SAEs.

Computed Tomography Perfusion Imaging Study of Intracranial Complex Aneurysms Treated by Internal Maxillary Artery Bypass Grafting

BACKGROUND

Cerebral revascularization strategies through extracranial to intracranial bypass have been adopted in the management of complex intracranial aneurysms. The internal maxillary artery used as a donor in a bypass is an effective method. At present, there are few quantitative analyses of cerebral blood flow perfusion. The main focus of this study was to evaluate the effectiveness of blood perfusion after bypass grafting.

METHODS

From April 2015 to December 2017, 19 patients who underwent internal maxillary artery radial artery middle cerebral artery bypass surgery with unobstructed bypass vessels were selected. Cerebral blood flow perfusion before and after bypass surgery was quantitatively evaluated by computed tomography perfusion imaging. The cerebral blood perfusion in the region of interest was measured by computed tomography perfusion.

RESULTS

The aneurysms were excised after trapping in 2 cases with mass effects and neural compression. Proximal occlusion of the parent artery was performed in 9 cases of fusiform or giant dissecting aneurysms. Trapping was performed after bypass surgery in 8 cases. Within 3 months after surgery, 17 patients had good outcomes. After the hypothesis test, there was a significant difference between the preoperative △cerebral blood volume and postoperative △cerebral blood volume in the anterior area of the semioval center cross section (P = 0.001 < 0.05).

CONCLUSIONS

The internal maxillary artery as a bypass donor is an effective method that can provide sufficient intracranial blood perfusion, and there is usually no cerebral ischemia in the surrounding area.

Reconstructive vs Deconstructive Endovascular Approach to Intradural Vertebral Artery Aneurysms: A Multicenter Cohort Study

BACKGROUND

Parent vessel sacrifice (PVS) has been a traditional way of treating complex aneurysms of the intradural vertebral artery (VA). Flow diversion (FD) has emerged as an alternative reconstructive option.

OBJECTIVE

To compare the long-term clinical and radiographic outcomes of intradural VA aneurysms following PVS or FD.

METHODS

We retrospectively reviewed and evaluated 43 consecutive patients between 2009 and 2018 with ruptured and unruptured intradural VA aneurysms treated by PVS or FD. Medical records including clinical and radiological details were reviewed.

RESULTS

A total of 43 intradural VA aneurysms were treated during this period. In the 14 PVS patients, the mean follow-up was 19.5 mo, and 71.4% of cases achieved modified Rankin scale (mRS) ≤2 at the last follow-up. A total of 86.5% of cases achieved complete occlusion. There was a 14.3% (2 cases) mortality rate, 14.3% (2 cases) postoperative ischemic complication rate, and 0% postoperative hemorrhaging rate. Retreatment was required in 1 case (7.1%). In the 29 FD patients, the mean follow-up was 21.8 mo, and 89.7% of cases achieved mRS ≤2 at the final follow-up. There was a 3.2% (1 case) mortality rate, 19.4% (6 cases) of postoperative ischemic complications, and 6.5% (2 cases) of postoperative hemorrhagic complications. Complete occlusion was seen in 86.5% patients. No cases required retreatment. Mortality and complication rates were not significantly different between PVS and PED (Pipeline Embolization Device) groups.

CONCLUSION

PVS was associated with comparable intraprocedural complications for VA aneurysms as compared to FD in the largest multicenter study to date. Both procedures have good long-term clinical and radiological outcomes.

Overview of Different Flow Diverters and Flow Dynamics

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

Endovascular treatment for ruptured vertebral dissecting aneurysms involving PICA: Reconstruction or deconstruction? Experience from 16 patients

OBJECTIVE

Ruptured vertebral dissecting aneurysms (VDAs) with posterior inferior cerebellar artery (PICA) involved require an optimal method to isolate the dissection and prevent the symptomatic infraction. This study aims to present our experience with both parent artery occlusion (PAO) and stent-assisted coiling (SAC), and provide a favorable strategy to the management of ruptured VDAs with PICA involved.

METHODS

We retrospectively reviewed patients with subarachnoid hemorrhage in our database from March 2013 to December 2018, suffering from dissecting aneurysms of the intradural vertebral arteries and endovascularly treated. A total of 16 cases with PICA involved were included. Basic information, aneurysm characteristics, procedure related complications and outcomes of patients were analyzed.

RESULTS

10 (62.5%) aneurysms were managed with PAO containing 3 proximal occlusion and 8 targeted-trapping preserved the PICA. 5 (31.3%) aneurysms were treated with SAC and one 6.3%) treated with vertebral artery to PICA stenting and trapping. Two (12.5%) patients died in the acute phase. Good clinical outcomes (modified Rankin Scale 0 to 3) were observed in 13(81.5%) cases in 30 days follow-up. PICA territory infraction was happened in one patient without any dysfunction. Favorable occlusion was observed in 9 of 12 (75%) which were free of further treatment.

CONCLUSIONS

For patients with good contralateral circulation, PAO could be a first line management for ruptured VDAs with PICA involved. Targeted-trapping with either reserved PICA or proximal occlusion with moderate coiling in aneurysm are promising modalities to prevent severe PICA infraction.

Efficacy and Safety of Flow-Diverter Therapy for Recurrent Aneurysms after Stent-Assisted Coiling

BACKGROUND AND PURPOSE

Flow-diverter treatment for previously stented aneurysms has been reported to be less effective and prone to complications. In this study, we evaluated the effectiveness and safety of flow diverters for recurrent aneurysms after stent-assisted coiling.

MATERIALS AND METHODS

Patients who underwent flow-diverter placement for recurrent aneurysms after stent-assisted coiling between March 2015 and March 2019 were recruited. Clinical and radiographic characteristics and clinical and angiographic outcomes were retrospectively evaluated.

RESULTS

Among 133 patients who underwent flow-diverter insertion, 17 (male/female ratio = 5:12; mean age, 53.8 years) were treated for recurrent aneurysms after stent placement with (n = 16) or without (n = 1) coiling. Eight patients initially presented with subarachnoid hemorrhage; 7, with headache; and 2, with visual field defects. Angiographic morphology included large/giant saccular in 12 patients, dissecting in 2, fusiform in 1, traumatic pseudoaneurysm in 1, and ruptured blood blister-like aneurysm in 1. The duration between the first treatment and flow-diverter placement ranged from 2 weeks to 15 months (median, 6 months). Flow-diverter placement was successful in all cases without any complications. All patients had favorable outcomes (mRS, 0-2), without any newly appearing symptoms. Aneurysms were followed up with conventional angiography at least once in 6-18 months. Sixteen aneurysms showed complete occlusion, and 1 aneurysm was enlarged.

CONCLUSIONS

Results from this case series investigating flow-diverter placement for recurrent aneurysms after stent-assisted coiling suggested that the procedure is safe and effective. Further study in a larger population may be warranted.

Endovascular Treatment of Large or Giant Non-saccular Vertebrobasilar Aneurysms: Pipeline Embolization Devices Versus Conventional Stents

Background

Endovascular treatment of large or giant non-saccular vertebrobasilar aneurysms (VBAs) by conventional stents is difficult and has unsatisfactory outcomes.

Object

This study was performed to retrospectively analyze the safety and efficacy of a flow diverter in treating large and giant non-saccular VBAs.

Methods

We identified 78 patients with 83 large or giant non-saccular VBAs who accepted endovascular treatment with a pipeline embolization device (PED) or conventional stent from January 2014 to June 2018. The technical details of the procedure, procedure-associated complications, angiographic outcomes, and clinical outcomes were evaluated.

Results

Forty-two patients (53.8%, 42/78) with 44 aneurysms (53.0%, 44/83) underwent endovascular treatment with PEDs. Thirty-six patients (46.2%, 36/78) with 39 aneurysms (47.0%, 39/83) underwent endovascular treatment with conventional stents. The complication rate of PED group and conventional stent group was 7.1% (3/42) and 5.6% (2/36), respectively (odds ratio, 0.765; 95% confidence interval, 0.121–4.851; P = 0.776). During a median follow-up time of 28.8 months, the complete occlusion rate in the PED group and conventional stent group was 90.2% (37/41) and 70.3% (26/37), respectively (odds ratio, 3.913; 95% confidence interval, 1.122–13.652; P = 0.032).

Conclusion

Endovascular treatment with a PED is a promising and safe modality for large and giant non-saccular VBAs, and the complication rate is acceptable, compared with conventional endovascular treatment.

Outcomes in Symptomatic Patients With Vertebrobasilar Dolichoectasia Following Endovascular Treatment

Objective: To evaluate whether the presenting symptoms of VBD predict outcomes following endovascular treatment. Methods: We retrospectively reviewed our institutional clinical database and identified 22 patients (all men; mean age: 52.6 years, range: 11-73 years) with a diagnosis of VBD, who underwent endovascular treatment from January 2010 to December 2017. Results: After analyzing the clinical and imaging data, we evaluated data for 22 symptomatic patients with VBD. At the time of VBD diagnosis, 13 patients (59%) had compressive symptoms, four (18%) had hemorrhagic symptoms, and five (23%) had ischemic symptoms. Nine of the 22 patients (41%), who presented with hemorrhagic and ischemic symptoms, achieved a satisfactory clinical and/or digital subtraction angiography imaging outcome after endovascular treatment. However, of the 13 patients who presented with compressive symptoms, seven (54%, 7/13) died from severe brainstem compression during follow-up; furthermore, magnetic resonance imaging showed worsening of the mass effect in eight patients with compressive symptoms (62%, 8/13). Conclusions: VBD is considered a challenging lesion without an ideal treatment modality. Endovascular treatment of VBD in patients presenting with compressive symptoms at diagnosis may not be beneficial. However, long-term outcomes following endovascular treatment may be acceptable in patients with non-compressive symptoms at diagnosis compared with those with compressive symptoms.

On Flow Diversion: The Changing Landscape of Intracerebral Aneurysm Management

Uptake of flow-diverting technology is rapidly outpacing the availability of clinical evidence. Most current usage is off-label, and the endovascular community is nearer the beginning than the end of the learning curve, given the number of devices in development. A comprehensive overview of technical specifications alongside key outcome data is essential both for clinical decision-making and to direct further investigations. Most-studied has been the Pipeline Embolization Device, which has undergone a transition to the Pipeline Flex for which outcome data are sparse or heterogeneous. Alternative endoluminal devices do not appear to be outperforming the Pipeline Embolization Device to date, though prospective studies and long-term data mostly are lacking, and between-study comparisons must be treated with caution. Nominal technical specifications may be unrelated to in situ performance, emphasizing the importance of correct radiologic sizing and device placement. Devices designed specifically for bifurcation aneurysms also lack long-term outcome data or have only recently become available for clinical use. There are no major studies directly comparing a flow-diverting device with standard coiling or microsurgical clipping. Data on flow-diverting stents are too limited in terms of long-term outcomes to reliably inform clinical decision-making. The best available evidence supports using a single endoluminal device for most indications. Recommendations on the suitability and choice of a device for bifurcation or ruptured aneurysms or for anatomically complex lesions cannot be made on the basis of current evidence. The appropriateness of flow-diverting treatment must be decided on a case-by-case basis, considering experience and the relative risks against standard approaches or observation.