A novel flow-diverting device (Tubridge) for the treatment of 28 large or giant intracranial aneurysms: a single-center experience

Treatment of giant intracranial aneurysms using the Pipeline flow-diverting stent: Long-term results from the International Retrospective Study of the Pipeline Embolization Device (IntrePED) study

BACKGROUND

Traditional endovascular treatments of giant intracranial aneurysms are associated with high rates of complications and retreatment. Our objective was to examine the safety and long-term efficacy of the Pipeline Embolization Device for treatment of these aneurysms.

METHODS

This retrospective study using the IntrePED database included all patients with giant intracranial aneurysms treated with the Pipeline device between July 2008 and February 2013. Efficacy outcomes were stratified by using the Raymond-Roy Occlusion Classification. Predefined safety outcomes included spontaneous rupture of the target aneurysm; ipsilateral intracranial hemorrhage; ischemic stroke; parent artery stenosis; and sustained cranial neuropathy.

RESULTS

Sixty-six embolizations were performed to treat 63 giant intracranial aneurysms (including 2 ruptured): 49 (77.8%) in the anterior and 14 (22.2%) in the posterior circulation. The median follow-up was 22.4 (0.1-60.5) months. Class I angiographic occlusion was achieved in 72.0% (36/50). The neurological morbidity/mortality rate was 23.8% (15/63), with higher rates in the posterior circulation than in the anterior circulation (22.4% vs. 28.6%). Among seven deaths, five had neurological causes. The procedure-related neurological morbidity and mortality rates were 22.7% (15/66) and 7.6% (5/66), respectively. The spontaneous rupture rate was 4.5% (3/66). Two spontaneous ruptures (1 death), 4/4 postprocedural intracranial hemorrhages, and 6/9 ischemic events occurred within 30 days. In-stent stenosis and new-onset cranial neuropathy were not observed during the angiographic follow-up period.

CONCLUSIONS

Although procedure-related neurological morbidity/mortality rates were not insignificant, this study confirms the feasibility and long-term efficacy of the Pipeline Embolization Device to treat giant intracranial aneurysms.

Comparison of pipeline embolization device and tubridge flow diverter for posterior circulation aneurysms: A multicentre propensity score matched study

Rationale and objectives

The off-label use of flow diverters (FDs) has broadened to include treating aneurysms in posterior circulation (PC). A novel flow diverter, the Tubridge flow diverter (TFD), has been created in China specifically for treating PC aneurysms. However, studies comparing between pipeline embolization device (PED) and TFD are rare. Thus, our study aimed to explore the effectiveness of PED and TFD in the treatment of PC aneurysms using a propensity score matched cohort design.

Methods

Retrospective data collection was conducted on patients who underwent treatment with either PED or TFD over the period from 2015 through 2020. Propensity score matching (PSM) was employed to calibrate for patient age; history of ischemic stroke; aneurysm size; morphology; location and neck; number of FDs; parent vessel diameter; and the employment of assisted coiling and balloon techniques. Data on previously ruptured aneurysms was not included in the analysis. A comparison was conducted between the two devices to assess perioperative complications, aneurysm occlusion rates, and functional outcomes.

Results

A total of 252 PC aneurysms were treated in 248 patients. Clinical and imaging follow-ups were lost in 26 and 47 patients, respectively. Major perioperative complications occurred in 7.5% of the cases, with favorable clinical outcomes in 91.0% and complete occlusion in 79.1%. Eighty-two (32.5%) aneurysms were treated with TFD, while 170 (67.5%) aneurysms were treated with PED. PSM was used to account for these significant variations, producing 82 matched pairs of unruptured aneurysms treated with PED or TFD. In terms of functional and angiographic outcomes, no significant differences were found between PED and TFD (functional outcome, p = 0.594 and angiographic outcome, p = 0.415). However, more perioperative major complications were found in patients treated with TFD (p = 0.005) compared with those receiving PED.

Conclusion

The comparative study of PED and TFD in the treatment of PC aneurysms resulted in positive clinical results and sustained occlusion rates, with acceptable perioperative complications. However, higher quality studies are needed to enhance our understanding of the use of FDs for treating of PC aneurysms.

Metal allergy and neurovascular stenting: A systematic review

BACKGROUND

Intracranial stents and flow diverters contain significant amounts of metals, notably nickel, which can cause allergic reactions in a considerable portion of the population. These allergic responses may lead to complications like in-stent stenosis (ISS) and TIA/Stroke in patients receiving stents or flow diverters for intracranial aneurysms.

METHODS

We conducted a systematic review of studies from inception until July 2023, which reported outcomes of patients with metal allergy undergoing neurovascular stenting. The skin patch test was used to group patients into those with positive, negative, or absent patch test results but with a known history of metal allergy.

RESULTS

Our review included seven studies with a total of 39 patients. Among them, 87% had a history of metal allergy before treatment. Most aneurysms (89%) were in the anterior circulation and the rest (11%) were in the posterior circulation. Skin patch tests were performed in 59% of patients, with 24% showing positive results and 33% negative. Incidental ISS was observed in 18% of patients, and the rate of TIA/Stroke was reported in 21%. The pooled rates of ISS and TIA/Stroke were higher in the first group (43% and 38%) compared to the second (18% and 9%) and third groups (15% and 15%), but these differences were not statistically significant.

CONCLUSIONS

The current neurosurgical literature does not provide a conclusive association between metal allergy and increased complications among patients undergoing neurovascular stenting. Further studies are necessary to gain a more comprehensive understanding of this topic.

Flow Diverter Performance Comparison of Different Wire Materials for Effective Intracranial Aneurysm Treatment

A flow diverter (FD) is an effective method for treating wide-necked intracranial aneurysms by inducing hemodynamic changes in aneurysms. However, the procedural technique remains challenging, and it is often not performed properly in many cases of deployment or placements. In this study, three types of FDs that changed the material of the wire were prepared within the same structure. Differences in physical properties, such as before and after delivery loading stent size, radial force, and radiopacity, were evaluated. The performances in terms of deployment and trackability force were also evaluated in a simulated model using these FDs. Furthermore, changes of deployment patterns when these FDs were applied to a 3D-printed aneurysm model were determined. The NiTi FD using only nitinol (NiTi) wire showed 100% size recovery and 42% to 45% metal coverage after loading. The low trackability force (10.9 to 22.9 gf) allows smooth movement within the delivery system. However, NiTi FD cannot be used in actual surgeries due to difficulties in X-ray identification. NiTi-Pt/W FD, a combination of NiTi wire and platinum/tungsten (Pt/W) wire, had the highest radiopacity and compression force (6.03 ± 0.29 gf) among the three FDs. However, it suffered from high trackability force (22.4 to 39.9 gf) and the end part braiding mesh tended to loosen easily, so the procedure became more challenging. The NiTi(Pt) FD using a platinum core nitinol (NiTi(Pt)) wire had similar trackability force (11.3 to 22.1 gf) to NiTi FD and uniform deployment, enhancing procedural convenience. However, concerns about low expansion force (1.79 ± 0.30 gf) and the potential for migration remained. This comparative analysis contributes to a comprehensive understanding of how different wire materials influence the performance of FDs. While this study is still in its early stages and requires further research, its development has the potential to guide clinicians and researchers in optimizing the selection and development of FDs for the effective treatment of intracranial aneurysms.

Flow diversion for compressive unruptured internal carotid artery aneurysms with neuro-ophthalmological symptoms: a systematic review and meta-analysis

BACKGROUND

Data on the safety and efficacy of flow diverters (FD) for the treatment of unruptured internal carotid artery (ICA) aneurysms with compressive neuro-ophthalmological symptoms (NOS) are scarce and comprise mainly small case series.

METHODS

We performed a search of three databases and included series with ≥10 patients, with unruptured aneurysms of the ICA and NOS, treated with FD. Random-effects analysis of treatment results and safety was performed.

RESULTS

A total of 22 studies reporting on 594 patients were included. Pooled proportions of NOS recovery, improvement, transient and permanent worsening were: 47.4% (95% CI 35.0% to 60.1%); 74.5% (95% CI 67.9% to 80.2%); 7.1% (95% CI 3.3% to 14.7%); and 4.9% (95% CI 3.2% to 7.4%), respectively. Rates of complete recovery and improvement in patients with isolated visual symptoms were 30.6% (95% CI 12.5% to 57.7%) and 56.6% (95% CI 42.3% to 69.9%). Isolated oculomotor symptoms recovered completely in 47.8% (95% CI 29.9% to 66.3%) and improved in 78% (95% CI 69.2% to 84.9%). Morbidity occurred in 5% (95% CI 2.8% to 9%) and mortality in 3.9% (95% CI 2% to 7.5%) of patients. An increased likelihood of symptom improvement was observed when treatment was performed early (<1 month) after symptom onset (OR=11.22, 95% CI 3.9% to 32.5%).

CONCLUSION

Flow diversion promotes recovery or improvement of compressive symptoms in a large proportion of patients but is associated with significant rates of morbidity and mortality. Transient and permanent NOS worsening is not uncommon. Early treatment is of utmost importance, as it increases the likelihood of symptom improvement more than 10-fold.

A novel flow diverter device (Tubridge) for the treatment of intracranial aneurysms: a systematic review and meta-analysis

The flow diverter (FD) device has become a feasible and effective option for treating intracranial aneurysms. This study aimed to evaluate the efficacy and safety of Tubridge FD (TFD) in treating intracranial aneurysms and provide evidence for further research and clinical application. Electronic databases, including PubMed, Web of Science, Embase, and the Cochrane Library from inception to July 31, 2022, were searched. The eligible studies should include TFD investigations in treating intracranial aneurysms. Pooled technical success rate, complete occlusion rate, improvement rate, stable rate, symptom elimination rate, and adverse events rate were calculated with either the fixed-effects model or the random-effects model, depending on the results of tests for heterogeneity. Egger's tests were performed to assess the potential publication bias. A total of 7 studies (145 patients) were included in this study. The pooled technical success rate was 0.98, the complete occlusion rate was 0.79, the improvement rate was 0.21, and the stable rate was 0.05. One included study reported that the surgery-related mortality rate in the Tubridge group was higher than that in the control group (3.66% vs. 1.61%), while the surgery-related morbidity rate in the Tubridge group was 2.4% and that in the control group was 0. Findings of this meta-analysis indicate that TFD manifests promising and effective performance with acceptable adverse events in the treatment of intracranial aneurysms.

Pipeline versus Tubridge in the treatment of unruptured posterior circulation aneurysms

BACKGROUND

To compare the safety and efficacy of pipeline embolization device (PED) and Tubridge flow diverter (TFD) for unruptured posterior circulation aneurysms.

METHODS

Posterior aneurysm patients treated with PED or TFD between January, 2019, and December, 2021, were retrospectively reviewed. Patients' demographics, aneurysm characteristics, treatment details, complications, and follow-up information were collected. The procedural-related complications and angiographic and clinical outcome were compared.

RESULTS

A total of 107 patients were involved; PED was applied for 55 patients and TFD for 52 patients. A total of 9 (8.4%) procedural-related complications occurred, including 4 (7.3%) in PED group and 5 (9.6%) in TFD group. During a mean of 10.3-month angiographic follow-up for 81 patients, complete occlusion was achieved in 35 (85.4%) patients in PED group and 30 (75.0%) in TFD group. The occlusion rate of PED group is slightly higher than that of TFD group. A mean of 25.0-month clinical follow-up for 107 patients showed that favorable clinical outcome was achieved in 53 (96.4%) patients in PED group and 50 (96.2%) patients in TFD group, respectively. No statistical difference was found in terms of procedural-related complications (p = 0.737), occlusion rate (p = 0.241), and favorable clinical outcome (0.954) between groups.

CONCLUSIONS

The current study found no difference in complication, occlusion, and clinical outcome between PED and TFD for unruptured PCAs.

Flow diversion for posterior circulation aneurysms: a multicenter retrospective study

Background

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

Objectives

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

Design

This is a multicenter retrospective study.

Methods

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

Results

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

Conclusion

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

Extracranial-intracranial bypass surgery for intracranial aneurysm of the anterior cerebral circulation: A systematic review and meta-analysis

Background

The safety of extracranial–intracranial (EC–IC) bypass in the management of anterior circulation intracranial aneurysms (IAs) remains to be determined. This systematic review aims to summarize the existing evidence and provide guidance for the precise management of IAs.

Data source

We constructed search strategies and comprehensively searched Pubmed, Medline, Embase, Web of science, and Cochrane library.

Methods

This systematic review was actualized according to the PRISMA statement. We evaluated study quality using the methodological index for non-randomized study (MINORS). Effect sizes were pooled using a random-effects model. Heterogeneity between studies was assessed using the I2 test. Publication bias was assessed using the Egger's test. The registration number for this systematic review is CRD42023396730.

Result

This systematic review included a total of 21 articles, involving 915 patients. Postoperative bypass patency rate was 99% (95% CI 0.98–1.00); short-term follow-up was 98% (95% CI 0.94–1.00); long-term follow-up was 95% (95% CI 0.93–0.97). The long-term follow-up occlusion rate of saphenous vein was higher than that of radial artery (OR 6.10 95% CI 1.04–35.59). Short-term surgery-related mortality was 0.3% (95% CI 0.000–0.012); long-term follow-up was 0.4% (95% CI 0.000–0.013); The proportion of patients with a score of 0–2 on the modified Rankin Scale (mRS) during long-term follow-up was 92% (95% CI 0.86–0.98). The incidence rates of long-term follow-up complications were: ischemic 3% (95% CI 0.01–0.06); hemorrhagic 1% (95% CI 0.00–0.03); neurological deficit 1% (95% CI 0.00–0.03); other 3% (95% CI 0.01–0.06).

Limitation

Most of the included studies were retrospective studies. Studies reporting preoperative status were not sufficient to demonstrate postoperative improvement. Lack of sufficient subgroup information such as aneurysm rupture status.

Conclusion

EC–IC therapy for anterior circulation IAs has a high safety profile. Higher level of evidence is still needed to support clinical decision.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023396730, identifier: CRD42023396730.

Tubridge flow diverter for the treatment of small and medium aneurysms

Background

Tubridge flow diverter is a widely used device aimed at reconstructing parent arteries and occluding complex aneurysms in China. The experience of Tubridge in treating small and medium aneurysms is still limited. In this study, we aimed to evaluate the safety and efficacy of the Tubridge flow diverter for the treatment of the two types of aneurysms.

Methods

We reviewed the clinical records of aneurysms treated with a Tubridge flow diverter between 2018 and 2021 in a national cerebrovascular disease center. Cases were divided into small and medium aneurysms according to aneurysm size. The therapeutic process, occlusion rate, and clinical outcome were compared.

Results

In total, 57 patients and 77 aneurysms were identified. The patients were divided into two groups: small aneurysms (39 patients, 54 aneurysms) and medium aneurysms (18 patients, 23 aneurysms). There were 19 patients with tandem aneurysms (a total of 39 aneurysms) in the two groups, among which 15 patients (30 aneurysms) were in the small aneurysm group and four patients (nine aneurysms) were in the medium aneurysm group. The results show that the mean maximal diameter/neck in the small and medium aneurysms was 3.68/3.25 and 7.61/6.24 mm, respectively. In total, 57 Tubridge flow diverters were successfully implanted without unfolding failure, and there were six patients with new mild cerebral infarction in the small aneurysm group. The complete occlusion rate on the last angiographic follow-up was achieved in 88.46% of the small aneurysms group and 81.82% of the medium aneurysms group. The complete occlusion rate of patients with tandem aneurysms in the last angiographic follow-up was 86.67% (13/15) of the small aneurysms group and 50% (2/4) of the medium aneurysm group. Intracranial hemorrhage was nonencountered in the two groups.

Conclusion

Our preliminary experience suggests that the Tubridge flow diverter might be a safe and effective treatment for small and medium aneurysms along the internal carotid artery. Long stents may increase the risk of cerebral infarction. Adequate evidence is required to clarify the definite indications and complications in a multicenter randomized controlled trial with a long-term follow-up.

Tubridge Flow Diverter for the Treatment of Unruptured Dissecting Cerebral Aneurysms

BACKGROUND

The Tubridge flow diverter is a device widely used in China aimed at reconstructing parent artery and occluding complex aneurysm. The experience of the Tubridge in treating unruptured vertebrobasilar artery dissecting aneurysms is still limited. In this study, we aimed to evaluate the safety and efficacy of the Tubridge flow diverter for the treatment of vertebrobasilar artery dissecting aneurysms.

METHODS

We reviewed the clinical records of aneurysms treated with the Tubridge flow diverter between 2019 and 2021 in a national cerebrovascular disease center. Therapeutic process, occlusion rate, and clinical outcome were compared.

RESULTS

Twenty-three patients with 23 vertebrobasilar artery aneurysms were identified. The results showed that the mean length and mean maximal width were 15.14 and 9.14 mm, respectively, in the vertebrobasilar artery. Twenty-four Tubridge flow diverters were successfully implanted without unfold failure. A complete occlusion rate at the last angiographic follow-up was achieved in 78.26% of vertebrobasilar artery aneurysms. Fifteen branch arteries were covered, and only 1 branch artery disappeared at follow-up. Mild asymptomatic cerebral infarction occurred in 3 patients (13.04%); intracranial hemorrhage was not found in the patients.

CONCLUSIONS

Our preliminary experience suggests that the Tubridge flow diverter might be a safe and effective tool for dissecting cerebral aneurysms. Branch arteries were well protected and mild asymptomatic cerebral infarction occurred in some patients. Adequate evidence is required to clear the definite indications and complications in a multicenter randomized controlled trial with a long-term follow-up.

Effect and safety of Tubridge flow diverter in the treatment of unruptured intracranial aneurysms

The effect and safety of the Tubridge flow diverting device are unknown in the treatment of intracranial aneurysms after optimization of the device, improvement in the deployment of the device, and accumulation of experience of using the device. This retrospective one-center study was performed to investigate the clinical effect and safety of the Tubridge flow diverting device in the treatment of unruptured intracranial aneurysms. Twenty-three patients with 33 unruptured intracranial aneurysms which were treated with the Tubridge device were retrospectively enrolled. The clinical data, endovascular procedure, complications, and follow-up were analyzed. Twenty-seven Tubridge devices were deployed to treat the 33 aneurysms, and the deployment was failed in 1 case, resulting in the success stenting rate of 96.3%. In 5 (15.2%) aneurysms, coils were loosely packed. Peri-procedural complications occurred in 2 patients (8.7%), including 1 procedure-related complication in which the distal end of a Tubridge device herniated into the aneurysm cavity. In another case, weakness of left upper limb occurred on the second day post procedure, with instent thrombosis being suspected, which was recovered after medication. No other complications occurred. Twenty-three (100%) patients had clinical follow-up 6 months later, with the mRS of 0 in 21 patients, 1 in 1, and 2 in 1. Five (21.7%) patients with 11 aneurysms underwent digital subtraction angiography at 6-month follow-up, with 8 aneurysms being completely occluded (Raymond grade I) and 3 aneurysms still visible (Raymond grade III). The Tubridge flow diverter may be safe and effective in the treatment of unruptured intracranial aneurysms with low perioperative complications and good follow-up outcomes even though multi-center and prospective clinical studies with a large size sample are still needed to validate these results.

Tubridge flow diverter alone vs. Tubridge flow diverter and coils for the treatment of intracranial aneurysms: A propensity score matching analysis

Background

The study was designed to assess the clinical performance of a tubridge flow diverter (TFD) in the treatment of intracranial aneurysms and to compare the efficacy and safety between intracranial aneurysms treated with TFD alone and TFD combined with coiling.

Methods

In this retrospective study, patients treated with the TFD alone or TFD combined with coiling between June 2018 to November 2022 were included. The patient demographics, the characteristics of the aneurysm, and the treatment outcomes between the two groups were compared. Propensity score matching was performed to match the variables with a significant difference between groups.

Results

In the current study, data from 93 consecutive patients including 104 aneurysms treated with TFD were analyzed. In total, 43 patients with 49 aneurysms were treated with TFD alone, and 50 patients with 55 aneurysms were treated with TFD combined with coiling. Aneurysms in the TFD combined with the coiling group were larger (12.9 ± 8.6 vs. 8.7 ± 8.8 mm, P = 0.016) and more likely to be saccular (92.7% vs. 75.5%, P = 0.027) than in the TFD alone group. No significant difference was observed between the two groups in terms of perioperative complication rate. During the follow-up period, the complete occlusion rate in the TFD combined with the coiling group was higher (80.0% vs. 43.8%, P = 0.001) than in the TFD alone group. These results were further confirmed using a propensity score matching analysis.

Conclusion

TFD combined with coiling can be a safe and effective alternative option for the treatment of complex aneurysms. Given the potential risks of these therapeutic modalities, thus very careful consideration is required on an individual patient basis.

A multicenter retrospective controlled study of the Pipeline™ and Tubridge™ Flow Diverter devices for intracranial wide-necked aneurysms

PURPOSE

To compare the safety and efficacy of PipelineTM and TubridgeTM Flow Diverter devices (FDs) in the treatment of intracranial wide-necked aneurysms.

METHODS

We retrospectively analyzed the clinical data of 92 patients with intracranial wide-necked aneurysms who were treated with those two flow-diverter devices (FDs) at four participating centers between July 2012 and December 2020.

RESULTS

This study included 92 patients who underwent endovascular therapy using either Pipeline™ (n = 39) or TubridgeTM (n = 53) for treating intracranial wide-necked aneurysms. The periprocedural complication developed in 2.56% (1/39) patients of Pipeline group and 3.77% (2/53) patients of the TubridgeTM group. During perioperative period, one patient in Pipeline™ group showed subarachnoid hemorrhage (2.56%, 1/39) and two ischemic complications in the Tubridge™ group (3.77%, 2/53). Follow-up assessments were conducted on 31 patients (79.49%) in the Pipeline™ group (the mean follow-up period was 9.7 ± 3.3 months). The rate of complete aneurysm occlusion at the final angiographic follow-up was 77.42%. Patients with a modified Rankin scale (mRS) score of 0.44 ± 0.31. Follow-up assessments were conducted on 42 patients (79.25%) in the TubridgeTM group (the mean follow-up period was 9.1 ± 4.4 months). The rate of complete aneurysm occlusion at the final angiographic follow-up was 85.71%. Patients with mRS score of 0.52 ± 0.28. Three patients showed parent artery stenosis, and one showed parent artery occlusion.

CONCLUSION

Both the PipelineTM and TubridgeTM are safe and effective for the treatment of intracranial wide-necked aneurysms, with no significant difference in the rate of complete aneurysm occlusion and perioperative complications between the two FDs.

Use of flow diverter device in basilar artery for aneurysm treatment: Case series and literature review

Background

Flow diverters (FDs) for the treatment of basilar artery (BA) aneurysms remain controversial. In this study, we report our initial experience of flow diversion for treatment of this pathology.

Methods

Consecutive patients with an aneurysm of the BA that was treated by implantation of the FD were included in our retrospective study. Procedural complications, aneurysm occlusion, and a functional outcome were evaluated. FD placement in BA for aneurysm treatment reported in the literature was also reviewed and summarized.

Results

Sixteen patients with 16 BA aneurysms were treated by FD implantation with (n = 8) or without (n = 8) adjunctive coiling. The Tubridge was used in 13 (81.3%) and Pipeline in 3 (18.8%) procedures. Average aneurysm size was 15.7 mm. Four aneurysms were located at the basilar apex, six at the basilar trunk, and six at the vertebrobasilar junction. Three patients experienced procedural complications (18.8%), including two ischemic strokes and one hydrocephalus, with resultant mortality in one case (6.3%). Median follow-up was 7.7 months and available for 15 aneurysms. Complete/near-complete occlusion was seen in 13 (86.7%) aneurysms.

Conclusion

In our initial experience, flow diversion is feasible and safe in the treatment of BA aneurysms with promising occlusion rates at mid-term follow-up. Larger cohort studies are required to validate these results.

Small Unruptured Intracranial Aneurysms Can Be Effectively Treated With Flow-Diverting Devices

Purpose

To investigate the effect and safety of flow diverters in the management of small (<10 mm in diameter) unruptured intracranial aneurysms.

Materials and Methods

One hundred and ten patients with 145 small intracranial aneurysms treated with flow diverters were retrospectively enrolled. The clinical, endovascular, and follow-up data were analyzed.

Results

One hundred twenty-one flow diverters were deployed for the treatment of 145 small intracranial aneurysms in 110 patients, and the stenting success rate was 99.1%. In 133 (91.7%) aneurysms, only flow-diverting devices were deployed, and in the rest 12 (8.3%) of aneurysms, coils were used to loosely pack the aneurysm after deployment of a flow-diverting device. Five patients (4.5%) experienced ischemic complications, but no hemorrhagic complications were occurred. All patients had clinical follow-up 6-18 (median 12) after the procedure, with the modified Rankin scale score (mRS) 0 in 101 patients, 1 in four patients, 2 in three patients, 4 in one patient, and 5 in one patient. Digital subtraction angiography was performed at follow-up in 90 (81.8%) patients with 118 (81.4%) aneurysms 6-18 months (median 12) after the procedure, with the Raymond grade I in 90 (76.2%) aneurysms and Raymond grade III in 28 (23.7%). Eighteen patients with 22 partially occluded aneurysms at the first angiographic follow-up experienced the second digital subtraction angiography 12-36 months (median 26) after the procedure, and 21 (95.5%) aneurysms were completely occluded. Two patients had asymptomatic in-stent stenosis.

Conclusion

Treatment of small unruptured intracranial aneurysms with flow diverters can be performed safely and effectively with satisfactory outcomes.

Modeling Flow Diverters using a Porous Medium Approach: A Fast Alternative to Virtual Flow Diverter Deployment

BACKGROUND

The Tubridge flow diverter (FD) is a novel device aimed at reconstructing the parent artery and eliminating the aneurysm. Numerical simulations based on virtual FD deployment allow the assessment of the complex nature of aneurismal flow changes before the actual intervention but are demanding on computational resources. Here, we evaluate an alternative strategy of modeling FD effects for the Tubridge system using a porous medium. The goal of this study is to reduce demands on time and complexity of the simulation procedure for applications in clinical research.

METHODS

Ten patient-specific aneurysm models were reconstructed from retrospectively collected diagnostic 3D-DSA images. Virtual FDs were deployed (SolidWorks, Meshmixer) and corresponding porous medium patches were constructed at the ostium with a research CFD prototype (Siemens Healthineers, Forchheim, Germany). Hemodynamic conditions were simulated in two approaches.

RESULTS

Hemodynamics inside the aneurysm based on these two approaches were compared. Both approaches yielded similar results. Mean wall shear stress (WSS) and mean pressure of the aneurysmal wall correlated significantly (r=0.8, r=1.0, p-value<0.05) as did mean velocity, mean pressure at a region inside the aneurysm, at the ostium and at a cross section containing the main vertex (for velocities r=0.9; for pressures r=1.0, p-value<0.05). The use of porous medium patches reduced the preparation and simulation time together by approximately 50%.

CONCLUSION

Using a porous medium approach yields comparable mean values for hemodynamic alterations compared to direct virtual FD simulations. Additionally, the porous medium approach greatly reduced the modeling complexity and computation time.

The 8-year single-center experience of telescoping flow diverter for complex intracranial aneurysms treatment

OBJECTIVE

Treatment of complex intracranial aneurysms (IAs) is still a challenging thing and this study aims to summarize the experience of telescoping flow diverters (FDs) in treating complex intracranial aneurysms.

METHOD

Between April 2013 to November 2020, 381 IA cases treated by flow diverters (FD) were retrieved from the database of 4988 IA cases, and finally 20 cases treated by telescoping FDs were enrolled for further analysis.

RESULT

Among 20 patients, 15 patients (75.0%) received Tubridge telescoping while 5 patients (25.0%) received PED telescoping. The technical success rate was 100%. The immediate occlusion results were: 7 cases of OKM grade A (35.0%), 11 cases of OKM grade B (55.0%), and 2 cases of OKM grade C (10.0%). No perioperative complications occurred. The clinical follow-up was available in 20 patients (100%) and the follow-up time was 6-96 months. One patient developed massive infarction and the other 19 patients were range between 0 and 2. The angiographic follow-up was available in 17 patients (85%) and the follow-up time was 6-27 months. The occlusion results were: 1 case of OKM grade B (5.9%), 6 cases of OKM grade C (35, 0.3%), and 10 cases of OKM grade D (58.8%). 2 patients (11.8%) developed occlusion of the patent artery.

CONCLUSION

Telescoping flow diverters showed low perioperative complications and high IA occlusion rate when treating complex intracranial aneurysms in follow-up time, which provides an alternative manner beyond conventional strategy for neurosurgeons.

Low-profile LEO baby stents using dual stenting technique in treating complex intracranial aneurysms located in small artery: Initial and mid-term outcome

BACKGROUND

Endovascular treatment of complex intracranial aneurysms (IAs) was challenging. Our retrospective study aimed to assess the efficacy and safety of LEO Baby stents using the dual stenting technique for complex IAs.

METHODS

Clinical and angiographic data of 15 IAs located in small arteries treated by LEO Baby stents in our neurosurgical center were retrospectively collected and analyzed between April 2019 to January 2021.

RESULTS

15 patients received dual stent-assisted coiling procedures and the stent configurations include 7 cases of T- configuration, 5 cases of parallel- configuration, 2 cases of Y- configuration, and 1case of X- configuration. 11 patients received dual stents deployment with only LEO Baby stents and 4 patients received LEO Baby stent combined with LVIS stent. Immediate postprocedural results showed Raymond I in 4 patients (26.7%), Raymond II in 5 patients (33.3%), and Raymond III in 6 patients (40.0%). One patient (6.7%) was confirmed with an ischemic complication during the procedure. All 15 patients (100%) received clinical follow-up ranging between 6 and 28 months. An mRS score of 0-2 was reached in all patients. 13 patients (86.7%) received angiographic clinical follow-up ranging between 6 and 20 months. The results revealed that Raymond I was achieved in 10 patients (76.9%) and Raymond II was achieved in 3 patients (23.1%). One patient (7.7%) in 6 months after the procedure was confirmed with asymptomatic in-stent stenosis.

CONCLUSION

This preliminary study suggests that dual stents deployment of LEO Baby stents was a feasible strategy for the treatment of complex IAs located in the small arteries.

Flow diversion for aneurysms beyond the circle of Willis: A preliminary experience

OBJECTIVE

To evaluate the safety and efficacy of flow diversion (FDs) for the aneurysms beyond the circle of Willis.

METHODS AND MATERIALS

We retrospectively reviewed the prospectively maintained database in our center and enrolled patients with aneurysms beyond the circle of Willis (defined as at or distal to the M1, A2, and P2 segments) that were treated with FDs.

RESULTS

Between July 2017 to December 2020, 28 patients with 28 aneurysms met the inclusion criteria and were included in this study, with a median age of 50 years old (IQR, 36-63 years). Thirty FDs, including 5 Pipelines and 25 Tubridge FDs, were deployed. Perioperative complications were noticed in 2 patients (7.1%), while asymptomatic adverse events occurred in another three patients (10.7%). Delayed complications occurred in 3.6% of patients (1/28). All patients received clinical follow-up, with the mortality and long-term morbidity of 0 and 3.6% (1/28), respectively. Angiographic follow-up data were available for 26 patients (92.9%) with an interval of 10 ± 7 months (ranged 2-26 months). Sixteen patients (61.5%) showed complete or nearly complete occlusion of aneurysms (OKM grading scale D and C); 6 cases (23.1%) were revealed incomplete occlusion (OKM grading scale B), and 4 cases (15.4%) remained unchanged (OKM grading scale A). The existence of the perforators derived from aneurysms was associated with a lower occlusion rate (p = 0.032).

CONCLUSION

Flow diversion is reliable in the treatment of distal aneurysms with a high technical success rate and low permanent disability rate. The presence of side branches derived from aneurysms was associated with a lower aneurysm occlusion rate.

Treatment of Intracranial Aneurysms Using the New Silk Vista Flow Diverter: Safety Outcomes at Short-Term Follow-Up

Background: Flow diverters are widely used as the first endovascular treatment option for complex brain aneurysms due to their high percentage of occlusion and low morbi-mortality. The Silk Vista device is a new generation of flow diverters designed to facilitate full visibility, improve apposition to the vessel wall, and enhance navigability. Indeed, its greatest advantage is that it enables the easier navigation of stents between 3.5 and 4.75 mm through a 0.021 microcatheter. The objective of this study was to evaluate the safety and effectiveness of Silk Vista systems for treating cerebral aneurysms.

Methods: This prospective observational study included 25 consecutive patients with 27 wide-necked unruptured aneurysms treated with SILK Vista who were retrospectively analyzed for safety and efficacy.

Results: Endovascular treatment was successfully performed in all patients. The final morbidity and mortality rates were both 0.0%. Short-term (3–5 months) angiographic follow-up revealed 21 complete occlusions and 6 near-complete occlusions. No significant parent artery stenosis was observed.

Conclusions: This report demonstrates the efficacy of Silk Vista in treating brain aneurysms, although longer experiences should be carried out to confirm our results.

Flow-diverting device versus coil embolization for unruptured intracranial aneurysm: A meta-analysis

BACKGROUND

Both coil embolization (CE) and flow-diverting device (FDD) placement are widely used for treatment of intracranial aneurysms (IAs). The aim of this meta-analysis is to compare the relative clinical safety and efficacy of FDD and CE for the treatment of unruptured IAs.

METHODS

The PubMed, Embase, and Cochrane Library databases were searched for relevant studies from the date of inception through April 2020. The primary endpoint for this meta-analysis was the 6-month rate of complete occlusion, while secondary endpoints included rates of retreatment, complications, and parental arterial patency.

RESULTS

This meta-analysis includes 8 studies, which included 839 total patients that underwent FDD and 2734 that underwent CE. FDD group exhibited a significantly higher pooled 6-month complete occlusion rate (P = .02). The subgroup analysis demonstrated that FDD treatment was associated with significantly higher pooled 6-month complete occlusion rates in patients with large or giant IAs (P < .00001), whereas no differences in 6-month complete occlusion rates were observed between the FDD and CE groups of patients with non-large/giant IAs (P = .83). The pooled retreatment (P = .16) and complication (P = .15) rates were comparable between 2 groups. The CE group exhibited significantly higher pooled parent artery patency rate (P = .01). The funnel plots did not reveal any evidence of publication bias.

CONCLUSIONS

FDDs can be used to effectively and safely treat large and giant IAs, achieving higher rates of complete occlusion than CE treatment. For non-large/giant IAs, we observed comparable efficacy between FDD and CE treatments.

A heparin-rosuvastatin-loaded P(LLA-CL) nanofiber-covered stent inhibits inflammatory smooth-muscle cell viability to reduce in-stent stenosis and thrombosis

Background

An endovascular covered-stent has unique advantages in treating complex intracranial aneurysms; however, in-stent stenosis and late thrombosis have become the main factors affecting the efficacy of covered-stent treatment. Smooth-muscle-cell phenotypic modulation plays an important role in late in-stent stenosis and thrombosis. Here, we determined the efficacy of using covered stents loaded with drugs to inhibit smooth-muscle-cell phenotypic modulation and potentially lower the incidence of long-term complications.

Methods

Nanofiber-covered stents were prepared using coaxial electrospinning, with the core solution prepared with 15% heparin and 20 µM rosuvastatin solution (400: 100 µL), and the shell solution prepared with 120 mg/mL hexafluoroisopropanol. We established a rabbit carotid-artery aneurysm model, which was treated with covered stents. Angiography and histology were performed to evaluate the therapeutic efficacy and incidence rate of in-stent stenosis and thrombosis. Phenotype, function, and inflammatory factors of smooth-muscle cells were studied to explore the mechanism of rosuvastatin action in smooth-muscle cells.

Result

Heparin–rosuvastatin-loaded nanofiber scaffold mats inhibited the proliferation of synthetic smooth-muscle cells, and the nanofiber-covered stent effectively treated aneurysms in the absence of notable in-stent stenosis. Additionally, in vitro experiments showed that rosuvastatin inhibited the smooth-muscle-cell phenotypic modulation of platelet-derived growth factor-BB induction and decreased synthetic smooth-muscle-cell viability, as well as secretion of inflammatory cytokines.

Conclusion

Rosuvastatin inhibited the abnormal proliferation of synthetic smooth-muscle cells, and heparin–rosuvastatin-loaded covered stents reduced the incidence of stenosis and late thrombosis, thereby improving the healing rates of stents used for aneurysm treatment.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00867-8.

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.

Review of current intracranial aneurysm flow diversion technology and clinical use

Endovascular treatment of intracranial aneurysms (IAs) has evolved considerably over the past decades. The technological advances have been driven by the experience that coils fail to completely exclude all IAs from the blood circulation, the need to treat the diseased parent vessel segment leading to the aneurysm formation, and expansion of endovascular therapy to treat more complex IAs. Stents were initially developed to support the placement of coils inside wide neck aneurysms. However, early work on stent-like tubular braided structure led to a more sophisticated construct that then later was coined as a flow diverter (FD) and found its way into clinical application. Although FDs were initially used to treat wide-neck large and giant internal carotid artery aneurysms only amenable to surgical trap with or without a bypass or endovascular vessel sacrifice, its use in other types of IAs and cerebrovascular pathology promptly followed. Lately, we have witnessed an explosion in the application of FDs and subsequently their modifications leading to their ubiquitous use in endovascular therapy. In this review we aim to compile the available FD technology, evaluate the devices' peculiarities from the authors' perspective, and analyze the current literature to support initial and expanded indications, recognizing that this may be outdated soon.

Endovascular treatment of complex middle cerebral artery aneurysms using TuBridge flow diverters

BACKGROUND

The safety and efficacy of the TuBridge flow diverter in treating middle cerebral artery aneurysms remains unknown. In this study, we report our preliminary experience treating complex middle cerebral artery aneurysms using the TuBridge flow diverter.

METHODS

A prospectively maintained database of intracranial aneurysms treated with the TuBridge flow diverter was retrospectively reviewed, and patients with middle cerebral artery aneurysms were included in this study. Demographics, aneurysm features, complications, and clinical and angiographic outcomes were assessed. Evaluation of the angiographic results included occlusion grade of aneurysm (O'Kelly-Marotta grading scale), patency of jailed branch(es), and in-stent stenosis.

RESULTS

Eight patients with eight middle cerebral artery aneurysms were included in this study. The mean aneurysm size was 11.8 ± 6.8 mm. There were no procedure-related complications and there was no morbidity or mortality at a mean follow-up of 11.3 ± 3.6 months. All patients had follow-up angiograms at a mean of 7.5 ± 4.0 months after surgery. Of the eight patients, there was 1 (12.5%) O'Kelly-Marotta grading scale A, 3 (37.5%) O'Kelly-Marotta grading scale B, 1 (12.5%) O'Kelly-Marotta grading scale C, and 3 (37.5%) O'Kelly-Marotta grading scale D. Of the seven patients with jailed branch, the blood flow of jailed branch was unchanged in 4 (57.1%), decreased in 2 (28.6%), and occluded in 1 (14.3%). In-stent stenosis was mild in 2 (25%) patients and moderate in 1 (12.5%) patient.

CONCLUSION

Midterm results suggest that endovascular treatment of middle cerebral artery aneurysms using the TuBridge flow diverter is safe and associated with good outcomes. The TuBridge flow diverter may be an option for complex middle cerebral artery aneurysms that are difficult to treat with either clipping or coiling.

p64 flow diverter: Results in 108 patients from a single center

BACKGROUND AND PURPOSE

Flow diverters are increasingly used to treat intracranial aneurysms. We report the safety and efficacy of the p64 flow diverter, a resheathable and detachable device for intracranial aneurysms.

MATERIALS AND METHODS

We retrospectively reviewed 108 patients with 109 aneurysms treated with the p64 between March 2014 and July 2019. There were 87 women and 21 men, mean age 57 years. Of 109 aneurysms, 74 were discovered incidentally, 12 were symptomatic, 18 were previously treated, and five were ruptured dissection aneurysms. A total of 10 aneurysms were located in the posterior circulation. The mean aneurysm or remnant size was 8.1 mm.

RESULTS

Hemorrhage by perforation with the distal guidewire occurred in two patients with permanent neurological deficits in one. In one patient, acute in-stent occlusion caused infarction with a permanent deficit. Permanent morbidity was 1.9% (2 of 108, 95%CI 0.1-6.9%); there was no mortality. During follow-up, three in-stent occlusions occurred, all asymptomatic. There were no delayed hemorrhagic complications. At six months, 77 of 96 aneurysms (80.2%) were completely occluded, and at last follow-up, this increased to 93 of 96 aneurysms (96.9%). In-stent stenosis at any degree occurred in 11 patients, progressing to asymptomatic complete occlusion in one. In the other patients, stenosis resolved or improved at further follow-up.

CONCLUSION

The p64 offers an effective and safe treatment option. Aneurysm occlusion rate was 97% at last follow-up, mostly achieved with a single device. There were no delayed hemorrhagic complications. Delayed in-stent stenosis infrequently progresses to occlusion but remains a matter of concern.

Advances in endovascular aneurysm management: flow modulation techniques with braided mesh devices

Flow diverters and flow disruption technology, alongside nuanced endovascular techniques, have ushered in a new era of treating cerebral aneurysms. Here, we provide an overview of the latest flow modulation devices and highlight their clinical applications and outcomes.

Endovascular treatment of traumatic carotid pseudoaneurysm with Tubridge flow diverter: A case report

Traumatic pseudoaneurysm is a rare lesion with a high risk of rupture, and represents one of the most difficult lesions to treat, either surgically or endovascularly. Herein, we describe the case of a 32-year-old man with a traumatic pseudoaneurysm of the internal carotid artery, which was treated by overlapped flow diverters (Tubridge). The patient recovered well, and the follow-up angiography at four months showed complete occlusion of the pseudoaneurysm and patency of the internal carotid artery and the ophthalmic artery.

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.

Endovascular Metal Devices for the Treatment of Cerebrovascular Diseases

Cerebrovascular disease involves various medical disorders that obstruct brain blood vessels or deteriorate cerebral circulation, resulting in ischemic or hemorrhagic stroke. Nowadays, platinum coils with or without biological modification have become routine embolization devices to reduce the risk of cerebral aneurysm bleeding. Additionally, many intracranial stents, flow diverters, and stent retrievers have been invented with uniquely designed structures. To accelerate the translation of these devices into clinical usage, an in-depth understanding of the mechanical and material performance of these metal-based devices is critical. However, considering the more distal location and tortuous anatomic characteristics of cerebral arteries, present devices still risk failing to arrive at target lesions. Consequently, more flexible endovascular devices and novel designs are under urgent demand to overcome the deficiencies of existing devices. Herein, the pros and cons of the current structural designs are discussed when these devices are applied to the treatment of diseases ranging broadly from hemorrhages to ischemic strokes, in order to encourage further development of such kind of devices and investigation of their use in the clinic. Moreover, novel biodegradable materials and drug elution techniques, and the design, safety, and efficacy of personalized devices for further clinical applications in cerebral vasculature are discussed.

The use of flow diverters to treat small (≤5 mm) ruptured, saccular aneurysms

Background:

There is limited published literature on the use of flow diverting stents (FDS) to treat ruptured intracranial aneurysms in the acute stage. We present our experience of using FDS to treat small (≤5 mm) ruptured aneurysms.

Methods:

We retrospectively identified all patients with ≤5 mm ruptured aneurysms treated exclusively with FDS between February 2009 and February 2016. We recorded demographic data, the Hunt and Hess score, aneurysm location and size, therapeutic intervention, immediate angiographic and clinical result, and clinical and radiological follow-up information.

Results:

We identified seven patients (four females) with average age 59.8 ± 10 years (range 48–75). The average aneurysm fundus size was 2.7 ± 0.76 mm (range 1–4 mm). The average time from ictus to treatment was 6.3 days (range 1–14 days) and there were no cases of repeat rupture prior to treatment or intraoperative rupture. Angiographic follow-up was available in five patients. At initial follow-up, aneurysms (100%) were completely occluded raymond roy classification 1 (RRC 1). None of the aneurysms re-ruptured following treatment. Clinically, six patients were discharged with good functional outcome modified Rankin Score (mRS ≤2). There were no mortalities.

Conclusion:

The use of FDS to treat small, ruptured, saccular aneurysms is feasible; however, the use of FDS should not be considered first-line treatment. Further studies are required to determine the safety and efficacy of the use of FDS in the acute situation.

Parent Artery Reconstruction for Large or Giant Cerebral Aneurysms Using the Tubridge Flow Diverter: A Multicenter, Randomized, Controlled Clinical Trial (PARAT)

BACKGROUND AND PURPOSE

Although flow diverters have been reported with favorable clinical and angiographic outcomes in various literatures, randomized trials determining their true effectiveness and safety are still in lack. The Parent Artery Reconstruction for Large or Giant Cerebral Aneurysms Using the Tubridge Flow Diverter (PARAT) trial was designed to evaluate the safety and efficacy of the Tubridge flow diverter in the treatment of large or giant aneurysms in comparison with Enterprise stent-assisted coiling.

MATERIALS AND METHODS

This prospective, multicenter, randomized trial was conducted at 12 hospitals throughout China. Enrolled adults with unruptured large/giant intracranial aneurysms were randomly assigned (1:1) to receive either Enterprise stent-assisted coiling or Tubridge flow diverter implantation. The primary end point was complete occlusion at 6-month follow-up, while secondary end points included technical success, mortality, target vessel-related stroke, aneurysm bleeding, in-stent stenosis, parent artery occlusion, and the frequency of all adverse events.

RESULTS

Among 185 enrolled subjects, 41 withdrew before procedure initiation. Overall, 82 subjects underwent Tubridge implantation, and 62 subjects were primarily treated with stent-assisted coiling. The results of 6-month follow-up imaging included complete occlusion rates of 75.34% versus 24.53% for the Tubridge and stent-assisted coiling groups, respectively, with a calculated common odds ratio of 9.4 (95% confidence interval, 4.14-21.38; P < .001). There was a higher, nonsignificant frequency of complications for Tubridge subjects. Multivariate analysis showed a decreased stroke rate at the primary investigational site, with a marginal P value (P = .051).

CONCLUSIONS

This trial showed an obviously higher rate of large and giant aneurysm obliteration with the Tubridge FD over Enterprise stent-assisted coiling. However, this higher obliteration rate came at the cost of a nonsignificantly higher rate of complications. Investigational site comparisons suggested that a learning curve for flow-diverter implantation should be recognized and factored into trial designs.

The Use of Flow Diverting Stents to Treat Para-Ophthalmic Aneurysms

Background and purpose

Few publications have dealt exclusively with the use of flow diverter stents for the treatment of para-ophthalmic aneurysms. We sought to determine the efficacy of flow diverting stents (FDSs) to treat aneurysms in this specific location.

Methods

We retrospectively reviewed our database of prospectively collected information for all patients treated with flow diversion for an unruptured saccular para-ophthalmic aneurysm between September 2009 and January 2016. The aneurysm fundus size, neck size, number and type of FDS, complications, and follow-up data were recorded.

Results

We identified 74 patients that matched our inclusion criteria. Of these patients, 18 patients were male (24.3%). The average fundus size was 4.8 mm, 11 aneurysms had previous coil occlusions and 63 were treated solely with flow diversion. At an initial angiographic follow-up (mean avg. 3.2 months), 71.8% of the aneurysms were occluded, and at the last follow-up (mean avg. 31.8 months), 88.9% of aneurysms were occluded. One patient suffered permanent morbidity (1.36%) secondary to interruption of the antiplatelet medication and another died (1.36%) secondary to in-stent thrombosis that was also due to an interruption in the antiplatelet medication.

Conclusion

Treatment of saccular para-ophthalmic aneurysms with FDS is feasible and carries a high degree of technical success with low complication rates and excellent rates of aneurysm exclusion.

A Novel Flow Diverter (Tubridge) for the Treatment of Recurrent Aneurysms: A Single-Center Experience

Objective

The Tubridge flow diverter (FD) is a novel device aimed at reconstructing the parent artery and occluding complex aneurysms. Retreatment of recurrent aneurysms using the FD is challenging. We report our initial experience in the repair of aneurysm recurrence with the FD.

Materials and Methods

A database was reviewed prospectively, and 8 patients with 8 recurrent aneurysms (mean size, 16.7 mm) were identified. Four aneurysms had previously ruptured. The previous aneurysm treatment consisted of coiling in 1 aneurysm and single-stent-assisted coiling in 7 aneurysms. The procedural complications and clinical and angiographic outcomes were analyzed.

Results

Six aneurysms were treated by using a single Tubridge FD alone, while the remaining 2 were treated with FD + coiling. The immediate results of the 8 aneurysms were that they all showed incomplete occlusion. Neither major ischemic nor hemorrhagic complications occurred; however, 1 patient experienced a vasospasm. Follow-up angiographies were available for 7 aneurysms; the mean follow-up was 16.9 months (7–36 months). Five aneurysms were completely occluded, whereas 2 had a residual neck. Severe asymptomatic stenosis of 1 parent artery of a vertebral artery dissecting aneurysm was found. All visible branches covered by the FD were patent. All patients were clinically assessed as having attained a favorable outcome (modified Rankin Scale score ≤ 2) at discharge and follow-up.

Conclusion

In selected patients, the Tubridge FD can provide a safe and efficient option for the retreatment of recurrent aneurysms. Nevertheless, attention should be paid to several technical points.

Complications associated with the use of flow-diverting devices for cerebral aneurysms: a systematic review and meta-analysis

OBJECTIVE

The objective of this study was to review the literature on the use of flow-diverting devices (FDDs) to treat intracranial aneurysms (IAs) and to investigate the safety and complications related to FDD treatment for IAs by performing a meta-analysis of published studies.

METHODS

A systematic electronic database search was conducted using the Springer, EBSCO, PubMed, Medline, and Cochrane databases on all accessible articles published up to January 2016, with no restriction on the publication year. Abstracts, full-text manuscripts, and the reference lists of retrieved articles were analyzed. Random-effects meta-analysis was used to pool the complication rates across studies.

RESULTS

Sixty studies were included, which involved retrospectively collected data on 3125 patients. The use of FDDs was associated with an overall complication rate of 17.0% (95% confidence interval [CI] 13.6%–20.5%) and a low mortality rate of 2.8% (95% CI 1.2%–4.4%). The neurological morbidity rate was 4.5% (95% CI 3.2%–5.8%). No significant difference in the complication or mortality rate was observed between 2 commonly used devices (the Pipeline embolization device and the Silk flow-diverter device). A significantly higher overall complication rate was found in the case of ruptured IAs than in unruptured IA (odds ratio 2.3, 95% CI 1.2–4.3).

CONCLUSIONS

The use of FDDs in the treatment of IAs yielded satisfactory results with regard to complications and the mortality rate. The risk of complications should be considered when deciding on treatment with FDDs. Further studies on the mechanism underlying the occurrence of adverse events are required.

Safety and efficiency of flow diverters for treating small intracranial aneurysms: A systematic review and meta-analysis

Background

We evaluated the safety and efficiency of flow diverters (FDs) in treating small intracranial aneurysms (IAs).

Materials and Methods

We reviewed the literature published in PubMed and EMBASE. R for Project software was used to calculate the complete aneurysm occlusion rates, procedure-related neurologic mortality, procedure-related neurologic morbidity and procedure-related permanent morbidity.

Results

Ten observational studies were included in this analysis. The complete aneurysm occlusion rate was 84.23% (80.34%–87.76%), the procedure-related neurologic mortality was 0.87% (0.29%–1.74%), the procedure-related neurologic morbidity rate was 5.22% (3.62%–7.1%), the intracerebral haemorrhage rate was 1.42% (0.64%–2.49%), the ischemic rate was 2.35% (1.31%–3.68%), the subarachnoid haemorrhage rate was 0.03% (0%–0.32%) and the procedure-related permanent morbidity was 2.41% (0.81%–4.83%).

Conclusions

Treatment of small IAs with FDs may be correlated with high complete occlusion rates and low complication rates. Future long-term follow-up randomized trials will determine the optimal treatment for small IAs.

Cerebral aneurysm treatment: modern neurovascular techniques

Endovascular treatment of cerebral aneurysm continues to evolve with the development of new technologies. This review provides an overview of the recent major innovations in the neurointerventional space in recent years.

Virtual-versus-Real Implantation of Flow Diverters: Clinical Potential and Influence of Vascular Geometry

BACKGROUND AND PURPOSE

Intracranial stents have become extremely important in the endovascular management of complex intracranial aneurysms. Sizing and landing zone predictions are still very challenging steps in the procedure. Virtual stent deployment may help therapeutic planning, device choice, and hemodynamic simulations. We aimed to assess the predictability of our recently developed virtual deployment model by comparing in vivo and virtual stents implanted in a consecutive series of patients presenting with intracranial aneurysms.

MATERIALS AND METHODS

Virtual stents were implanted in patient-specific geometries of intracranial aneurysms treated with the Pipeline Embolization Device. The length and cross-section of virtual and real stents measured with conebeam CT were compared. The influence of vessel geometry modifications occurring during the intervention was analyzed.

RESULTS

The virtual deployment based on pre- and poststent implantation 3D rotational angiography overestimated (underestimated) the device length by 13% ± 11% (-9% ± 5%). These differences were highly correlated (R² = 0.67) with the virtual-versus-real stent radius differences of -6% ± 7% (5% ± 4%) for predictions based on pre- and poststent implantation 3D rotational angiography. These mismatches were due principally to implantation concerns and vessel-shape modifications.

CONCLUSIONS

The recently proposed geometric model was shown to predict accurately the deployment of Pipeline Embolization Devices when the stent radius was well-assessed. However, unpredictable delivery manipulations and variations of vessel geometry occurring during the intervention might impact the stent implantation.

Late recurrence of a completely occluded large intracranial aneurysm treated with a Tubridge flow diverter

We report a rare case of recurrence of a large intracavernous aneurysm after angiography proved complete occlusion. The aneurysm was treated by a combination of a Tubridge flow diverter and coils, and balloon angioplasty, after flow diverter devices deployment for parent vessel stenosis. Six month angiographic follow-up demonstrated complete occlusion. Unfortunately, obvious aneurysm recurrence was confirmed on 2 year angiographic follow-up. The probable mechanism of recurrence was analyzed.

Late recurrence of a completely occluded large intracranial aneurysm treated with a Tubridge flow diverter

We report a rare case of recurrence of a large intracavernous aneurysm after angiography proved complete occlusion. The aneurysm was treated by a combination of a Tubridge flow diverter and coils, and balloon angioplasty, after flow diverter devices deployment for parent vessel stenosis. Six month angiographic follow-up demonstrated complete occlusion. Unfortunately, obvious aneurysm recurrence was confirmed on 2 year angiographic follow-up. The probable mechanism of recurrence was analyzed.

Long-Term Outcome of Tubridge Flow Diverter(S) in Treating Large Vertebral Artery Dissecting Aneurysms-A Pilot Study

BACKGROUND AND PURPOSE

The experience of flow diverters (FDs) in treating large vertebral artery-dissecting aneurysms (VADAs) is still limited. This study was conducted to present our long-term outcome of VADAs treated with a Tubridge flow diverter (TFD), a new device developed in China.

MATERIALS AND METHODS

The clinical and angiographic data of six patients harboring large VADAs and treated with TFDs were prospectively collected and analyzed.

RESULTS

A total of nine TFDs were successfully implanted in six patients. Angiographic follow-up images were available for all patients at a median of 26.0 (18.5, 37.5) months after treatment. Five of the six VADAs were completely occluded, and the last was improved (near complete occlusion). In-stent stenosis was detected in one case and was handled appropriately by angioplasty and stenting. All covered branches and parent arteries remained patent. There were no complications or new neurological deficits observed in any of the patients. At the latest clinical follow-up (36.5 (26.0, 44.5) months), all patients achieved 0 in the modified Rankin scale score.

CONCLUSIONS

Our preliminary experience suggests that the Tubridge flow diverter might be an alternative treatment for large and recurrent dissecting aneurysms derived from the vertebral artery.

Relationships and redundancies of selected hemodynamic and structural parameters for characterizing virtual treatment of cerebral aneurysms with flow diverter devices

BACKGROUND AND PURPOSE

To quantify the relationship and to demonstrate redundancies between hemodynamic and structural parameters before and after virtual treatment with a flow diverter device (FDD) in cerebral aneurysms.

METHODS

Steady computational fluid dynamics (CFD) simulations were performed for 10 cerebral aneurysms where FDD treatment with the SILK device was simulated by virtually reducing the porosity at the aneurysm ostium. Velocity and pressure values proximal and distal to and at the aneurysm ostium as well as inside the aneurysm were quantified. In addition, dome-to-neck ratios and size ratios were determined. Multiple correlation analysis (MCA) and hierarchical cluster analysis (HCA) were conducted to demonstrate dependencies between both structural and hemodynamic parameters.

RESULTS

Velocities in the aneurysm were reduced by 0.14m/s on average and correlated significantly (p<0.05) with velocity values in the parent artery (average correlation coefficient: 0.70). Pressure changes in the aneurysm correlated significantly with pressure values in the parent artery and aneurysm (average correlation coefficient: 0.87). MCA found statistically significant correlations between velocity values and between pressure values, respectively. HCA sorted velocity parameters, pressure parameters and structural parameters into different hierarchical clusters. HCA of aneurysms based on the parameter values yielded similar results by either including all (n=22) or only non-redundant parameters (n=2, 3 and 4).

CONCLUSION

Hemodynamic and structural parameters before and after virtual FDD treatment show strong inter-correlations. Redundancy of parameters was demonstrated with hierarchical cluster analysis.

China's Medical Education and Interventional Neuroradiology Training

China's medical education system is complex and consists of degree programs lasting from 3 to 8 years, the inconsistency across previous educational backgrounds is a challenge when implementing residency training objectives and contents. Only in several advanced medical universities, education for interventional neuroradiology (INR) is a part of a rotation in the 2-year training for neurosurgery. Advanced INR techniques are confined to big cities such as Beijing, Shanghai and Guangzhou, where most of the Chinese INRs have their 6 to 12 months fellowship to major medical centers. With a tremendous economic growth in the region, we expect that INR practice will evolve at an equally rapid pace, and information presented in this chapter may soon become obsolete.

Comparison of the flow diverter and stent-assisted coiling in large and giant aneurysms: safety and efficacy based on a propensity score-matched analysis

OBJECTIVES

The flow diverter (FD) is a device aimed at reconstructing the parent artery and occluding an aneurysm. We performed a propensity score-matched analysis to compare safety and efficacy between the FD and stent-assisted coiling.

METHODS

A database review was conducted to identify patients with large and giant unruptured aneurysms (aneurysms located in the ACA, MCA, or PCA were excluded) treated with the FD or stent-assisted coiling. A propensity score, representing the probability of using the FD, was generated for each aneurysm using the relevant patient and aneurysmal variables. Angiographic results, complications, and clinical outcomes were compared.

RESULTS

Forty-five aneurysms treated with the FD (FD alone: 32; FD+Coils: 13) and 45 treated with stent-assisted coiling were matched. The rate of complete occlusion was significantly (P = 0.0002) higher in the FD cohort than the conventional stent cohort at the 6-month follow-up. The FD cohort achieved greater improvement (P < 0.0001) and a lower rate of recurrence (P = 0.0001). The rate of periprocedural complications was similar, as was the proportion of patients who attained mRS ≤ 2 at discharge and at the 6-month follow-up.

CONCLUSIONS

Our findings provide reliable evidence demonstrating that the FD may be a preferred treatment option for large and giant unruptured aneurysms.

KEY POINTS

• Flow Diverter provided a higher complete occlusion rate at 6-month follow-up. • Flow Diverter achieved more progress occlusion and less recurrence. • Compared with the conventional stents, procedure-related morbidity of Flow Diverter was similar. • Flow Diverter is a preferred treatment for large and giant unruptured aneurysms.

Combined Effects of Flow Diverting Strategies and Parent Artery Curvature on Aneurysmal Hemodynamics: A CFD Study

PURPOSE

Flow diverters (FD) are increasingly being considered for treating large or giant wide-neck aneurysms. Clinical outcome is highly variable and depends on the type of aneurysm, the flow diverting device and treatment strategies. The objective of this study was to analyze the effect of different flow diverting strategies together with parent artery curvature variations on altering intra-aneurysmal hemodynamics.

METHODS

Four ideal intracranial aneurysm models with different parent artery curvature were constructed. Computational fluid dynamics (CFD) simulations of the hemodynamics before and after applying five types of flow diverting strategies (single FD, single FD with 5% and 10% packing density of coils, two FDs with 25% and 50% overlapping rate) were performed. Changes in pressure, wall shear stress (WSS), relative residence time (RRT), inflow velocity and inflow volume rate were calculated and compared.

RESULTS

Each flow diverting strategy resulted in enhancement of RRT and reduction of normalized mean WSS, inflow volume rate and inflow velocity in various levels. Among them, 50% overlapped FD induced most effective hemodynamic changes in RRT and inflow volume rate. The mean pressure only slightly decreased after treatment. Regardless of the kind of implantation of FD, the mean pressure, inflow volume rate and inflow velocity increased and the RRT decreased as the curvature of the parent artery increased.

CONCLUSIONS

Of all flow diverting strategies, overlapping FDs induced most favorable hemodynamic changes. Hemodynamics alterations post treatment were substantially influenced by parent artery curvature. Our results indicate the need of an individualized flow diverting strategy that is tailored for a specific aneurysm.