Flow Diverters for Intracranial Aneurysms

Predictors of aneurysm occlusion after treatment with flow diverters: a systematic literature review

BACKGROUND

Flow diverters (FDs) have become an integral part of treatment for brain aneurysms.

AIM

To summarize available evidence of factors associated with aneurysm occlusion (AO) after treatment with a FD.

METHODS

References were identified using the Nested Knowledge AutoLit semi-automated review platform between January 1, 2008 and August 26, 2022. The review focuses on preprocedural and postprocedural factors associated with AO identified in logistic regression analysis. Studies were included if they met the inclusion criteria of study details (ie, study design, sample size, location, (pre)treatment aneurysm details). Evidence levels were classified by variability and significancy across studies (eg, low variability ≥5 studies and significance in ≥60% throughout reports).

RESULTS

Overall, 2.03% (95% CI 1.22 to 2.82; 24/1184) of screened studies met the inclusion criteria for predictors of AO based on logistic regression analysis. Predictors of AO with low variability in multivariable logistic regression analysis included aneurysm characteristics (aneurysm diameter), particularly complexity (absence of branch involvement) and younger patient age. Predictors of moderate evidence for AO included aneurysm characteristics (neck width), patient characteristics (absence of hypertension), procedural (adjunctive coiling) and post-deployment variables (longer follow-up; direct postprocedural satisfactory occlusion). Variables with a high variability in predicting AO following FD treatment were gender, FD as re-treatment strategy, and aneurysm morphology (eg, fusiform or blister).

CONCLUSION

Evidence of predictors for AO after FD treatment is sparse. Current literature suggests that absence of branch involvement, younger age, and aneurysm diameter have the highest impact on AO following FD treatment. Large studies investigating high-quality data with well-defined inclusion criteria are needed for greater insight into FD effectiveness.

Flow diverters treatment planning of small- and medium-sized intracranial saccular aneurysms on the internal carotid artery via constraint-based virtual deployment

PURPOSE

The internal carotid artery (ICA) is a region with a high incidence for small- and medium-sized saccular aneurysms. However, the treatment relies heavily on the surgeon's experience to achieve optimal outcome. Although the finite element method (FEM) and computational fluid dynamics can predict the postoperative outcomes, due to the computational complexity of traditional methods, there is an urgent need for investigating the fast but versatile approaches related to numerical simulations of flow diverters (FDs) deployment coupled with the hemodynamic analysis to determine the treatment plan.

METHODS

We collected the preoperative and postoperative data from 34 patients (29 females, 5 males; mean age 55.74 ± 9.98 years) who were treated with a single flow diverter for small- to medium-sized intracranial saccular aneurysms on the ICA. The constraint-based virtual deployment (CVD) method is proposed to simulate the FDs expanding outward along the vessel centerline while be constrained by the inner wall of the vessel.

RESULTS

The results indicate that there were no significant differences in the reduction rates of wall shear stress and aneurysms neck velocity between the FEM and methods. However, the solution time of CVD was greatly reduced by 98%.

CONCLUSION

In the typical location of small- and medium-sized saccular aneurysms, namely the ICA, our virtual FDs deployment simulation effectively balances the computational accuracy and efficiency. Combined with hemodynamics analysis, our method can accurately represent the blood flow changes within the lesion region to assist surgeons in clinical decision-making.

Safety and efficacy of Surpass Evolve Flow diverter for intracranial aneurysms: A study of 116 patients

BACKGROUND AND PURPOSE

Flow diverter embolization is a recognized method for treating intracranial aneurysms. This study evaluates the safety and efficacy of the Surpass Evolve flow diverter in treating intracranial aneurysm.

MATERIAL AND METHODS

From May 2019 to June 2022, our center prospectively enrolled patients presenting with both ruptured and unruptured intracranial aneurysms. We assessed aneurysm occlusion, along with the occurrence of ischemic and hemorrhagic complications, and mortality at 6-months. The 3-month occlusion rate was determined using MR angiography, while the 6-month occlusion rate employed the O'Kelly-Marotta (OKM) grading scale on DSA.

RESULTS

A total of 116 patients with 120 aneurysms received treatment with the Surpass Evolve device. The average aneurysm size was 6.6 mm (range: 2-30 mm). All patients were administered two loading doses of ticagrelor (180 mg) one day before the procedure and 2 h pre-embolization. A procedural complication occurred in one case, involving wire-related perforation of an M3 branch distant from the giant aneurysm; however, this evolved favorably. There were no reported deaths linked to the treatment. Permanent neurological deficits were observed in 3 (2.5%) patients, primarily due to early in-stent thrombosis. MR angiography results at 3 months indicated complete occlusion for 87 out of 115 (75.6%) monitored aneurysms. The 6-month DSA showed neck remnant or complete occlusion (OKM grade C or D) in 86 out of the 107 (80.4%) patients who underwent follow-up.

CONCLUSION

The Surpass Evolve stands out as a reliable and effective flow diverter for the management of intracranial aneurysms.

Pipeline Embolization Device for intracranial aneurysms presenting with mass effect: a large Chinese cohort

BACKGROUND

Unruptured intracranial aneurysm treatment aims to reduce the risk of aneurysm rupture and bleeding, relieves symptoms and improve the quality of life for patients. This study aimed to assess the safety and efficacy of Pipeline Embolization Device (PED, Covidien/Medtronic, Irvine, CA) treatment for intracranial aneurysms presenting with mass effect in real-world settings.

METHODS

We selected patients from the PED in China Post-Market Multi-Center Registry Study with mass effect presentation. The study endpoints included postoperative mass effect deterioration and mass effect relief at follow-up (3-36 months). We conducted multivariate analysis to identify factors associated with mass effect relief. Subgroup analyses by aneurysm location, size and form were also performed.

RESULTS

This study included 218 patients with a mean age of 54.3±11.8 years and a female predominance of 74.0% (162/218). The postoperative mass effect deterioration rate was 9.6% (21/218). During a median follow-up period of 8.4 months, the mass effect relief rate was 71.6% (156/218). Notably, immediate aneurysm occlusion following treatment was significantly associated with mass effect relief (OR 0.392, 95% CI, 0.170 to 0.907, p=0.029). Subgroup analysis demonstrated that adjunctive coiling contributed to mass effect relief in cavernous aneurysms, while dense embolism impeded symptom relief in aneurysms<10 mm and saccular aneurysms.

CONCLUSIONS

Our data confirmed the efficacy of PED in relieving mass effect. The findings of this study provide support for endovascular treatment to alleviate mass effect in unruptured intracranial aneurysms.

TRIAL REGISTRATION NUMBER

NCT03831672.

Clinical Outcomes On Tubridge Flow Diverter in Treatmenting Intracranial Aneurysms: a Retrospective Multicenter Registry Study

PURPOSE

In China, the application of nitinol Tubridge flow diverter (TFD) has become popular for treating intracranial aneurysms (IAs). In this study, we investigated the safety outcomes of the application of TFD for treating IAs in real-world scenarios.

METHODS

We retrospectively analyzed aneurysms treated with TFD in 235 centers throughout China between April 2018 and April 2020. The primary endpoint was the event-free survival rate at 12 months, defined as the occurrence of morbidity (spontaneous rupture, intraparenchymal hemorrhage (IPH), ischemic stroke, and permanent cranial neuropathy) or death. Univariate and multivariate analyses were performed to assess the risk factors. A good outcome was defined as a modified Rankin Score (mRS) of 0-2.

RESULTS

We included 1281 unruptured aneurysms treated with TFD. The overall neurological morbidity and death rates after 12 months were 5.4 and 2.8%, respectively. Ischemic strokes were the most common complication (4.2%, P < 0.001). Cranial neuropathy, IPH, and spontaneous rupture occurred in 0.3%, 0.3%, and 0.5% of aneurysms, respectively. Univariate and multivariate analyses indicated that the male gender, older age, larger aneurysm diameter, and aneurysm located on BA were the independent risk factors for neurologic events. Aneurysm located on BA was the independent risk factor for ischemic strokes. Most patients (1222) had access to the mRS, and 93.2% of them achieved good outcomes.

CONCLUSION

Treatment of IAs with TFD was associated with low morbidity and mortality, most of which were ischemic events. Large posterior aneurysms might be associated with a higher complication rate.

TRIAL REGISTRATION

Retrospectively registered.

Safety and Efficacy of Flow Diverters for Treatment of Unruptured Anterior Communicating Artery Aneurysms: Retrospective Multicenter Study

BACKGROUND

The anterior communicating artery (AComm) region is the most common site of intracranial aneurysms, with increased rupture risk compared with other locations. Overall, flow diverters present as a safe and efficacious treatment for intracranial aneurysms, but there is paucity of data for their use in the treatment of unruptured AComm aneurysms. We present the largest multicentric analysis evaluating the outcomes of flow diverters in AComm aneurysm treatment.

METHODS

Databases from 10 centers were retrospectively reviewed for unruptured AComm aneurysms treated with flow diverters. Demographics, clinical presentation, radiographic characteristics, procedural complications, and outcomes were assessed.

RESULTS

A total of 144 patients harboring 147 AComm aneurysms were treated between January 2012 and December 2021. Seventy-four were women (51.4%) and median age was 60 (IQR 50-67) years. All were unruptured AComm aneurysms. Half of the cohort had similar anterior cerebral artery sizes (51.4%). The most common morphology was saccular (94.6%), with a branch involvement in 32.7% of cases. Median vessel diameter was 2.4 mm, and the Pipeline Flex was the most prevalent device (32.7%). Median follow-up time was 17 months, with complete occlusion in 86.4% at the last follow-up. Functional independence (modified Rankin Scale score 0-2) was reported in 95.1%. Intraprocedural complications occurred in 5.6%, and postoperative complications were noted in 9.7% of cases. Combined major complication and mortality rate was 2.1%.

CONCLUSIONS

Our study suggests that flow diverters are a useful treatment for AComm aneurysms. Mid-term results indicated favorable aneurysm occlusion with a good safety profile. Additional prospective studies with longer follow-up periods and independent adjudication are warranted to better assess these results.

Safety of dual antiplatelet therapy using aspirin and low-dose Prasugrel with platelet reactivity testing in flow diverter treatment of intracranial aneurysms

BACKGROUND

Dual antiplatelet therapy (DAPT) is standard care for intracranial stenting to prevent thrombotic complications. Clopidogrel resistance has resulted in patients receiving newer P2Y12 inhibitors like Prasugrel, which may reduce thrombotic complications but could increase haemorrhagic complications. This study, utilising platelet reactivity testing, compared thrombotic and haemorrhagic complications associated with Clopidogrel or 20 mg Prasugrel loading in patients treated with flow diverters (FD) for intracranial aneurysms.

METHODS

We retrospectively analysed prospectively collected data from 225 consecutive FD procedures. All patients received aspirin. 147 cases received Clopidogrel and 82 received Prasugrel. All patients had VerifyNow testing before the procedure.

RESULTS

P2Y12 non-responders were significantly more likely to have thrombotic complications than responders and hyper-responders (7% vs. 2%, p = 0.01). Low-dose Prasugrel resulted in a significantly lower rate of non-responders when compared with Clopidogrel (7% vs. 25%, p < 0.01). We found no statistically significant difference in rates of haemorrhage between the Clopidogrel and Prasugrel groups (2.4% vs. 3.9%, p = 0.47). There were 12 complications (≤7 days) in the Clopidogrel group versus 6 in the Prasugrel group (9% vs. 7.8%, respectively, p = 0.91) and a non-significant reduction in thrombotic complications in the Prasugrel group (5.2% vs. 3.9%, p = 0.88). No significant difference was shown in long-term complications between the groups (p = 0.33).

CONCLUSION

These results support the use of platelet reactivity testing and the safety of low-dose Prasugrel for FD treatment of intracranial aneurysms.

Early clinical experience with the new generation Pipeline Vantage flow diverter in the treatment of unruptured saccular aneurysms using short-term dual antiplatelet therapy

PURPOSE

The Pipeline Vantage flow diverter with Shield technology (PV) used in this study is a 4th-generation flow diverter (FD) designed to reduce thrombogenicity, promote endothelialization of the implant and increase efficiency in achieving aneurysm closure. In this study, we report the aneurysm occlusion rate, complication rate and clinical outcome with short-term dual antiplatelet therapy (DAPT) in the treatment of unruptured intracranial saccular aneurysms using the PV.

METHODS

We retrospectively identified patients treated between September 2021 and January 2023 with the PV and subsequently underwent short-term DAPT for 3 months. Patient and aneurysm characteristics, peri- and post-procedural complications, clinical outcomes and the grade of aneurysm occlusion were documented.

RESULTS

Thirty patients with 32 aneurysms were treated. Successful FD implantation was achieved in all cases (100%). No periprocedural complications were documented. The overall symptomatic complication rate was 10% and the neurologic, treatment-related symptomatic complication rate was 6.6%. Only one symptomatic complication (3.3%) was device-related. Permanent clinical deterioration occurred in 2/30 patients (6.6%), leading to deterioration of the mRS within the first 3 months after treatment. No mortality was documented. The rate of complete aneurysm occlusion after 3 months and after a mean imaging follow-up of 9.9 months was 65.6% and 75%, respectively.

CONCLUSION

Implantation of the PV for the treatment of saccular intracranial aneurysms achieves a good aneurysm occlusion rate with a low rate of complications. In addition, the use of short-term DAPT after PV implantation appears to be safe.

Predictors of aneurysmal occlusion following intracranial aneurysms treatment with pipeline embolization device

PURPOSE

Pipeline embolization device (PED) is thought to induce aneurysmal occlusion through diversion of flow away from the aneurysmal sac with subsequent thrombosis and endothelialization. The impact of different factors especially hypertension (HTN)-a known predisposing factor to hypercoagulability and altered endothelial function-on aneurysmal occlusion after flow diversion has not been studied. We sought to determine predictors of aneurysmal occlusion following PED treatment focusing on impact of blood pressure.

METHODS

Database of patients with cerebral aneurysms treated with PED from 2013 to 2019 at our institution was retrospectively reviewed. Patients were defined as hypertensive if (1) they had a documented history of HTN requiring anti-HTN medications or (2) average systolic blood pressure on three measurements was > 130 mmHg. The primary outcome was aneurysm occlusion status at the last imaging follow-up. Multivariable logistic regression model was constructed to assess the effect of HTN on occlusion, controlling for age, smoking, aneurysmal size, fusiform morphology, posterior circulation location, and incorporated branches.

RESULTS

A total of 331 aneurysms in 294 patients were identified for this analysis. The mean age was 59 years (79.9% female). Fifty-five percent of the cohort were classified as hypertensive. When controlling for other potential confounders, hypertensive patients trended toward higher odds of achieving complete occlusion compared to non-hypertensive patients (OR = 2.05; 95% CI = 0.99-4.25; p = 0.052). Meanwhile, age (OR = 0.91; 95% CI = 0.88-0.95; p < 0.001) and an incorporated branch into an aneurysm (OR = 0.22; 95% CI = 0.08-0.58; p < 0.002) were associated with decreased odds for complete aneurysmal occlusion.

CONCLUSION

Hypertensive patients show a trend toward higher odds of achieving complete occlusion when controlling for potential confounders. The HTN-induced hypercoagulable state, enhanced endothelial activation, and altered extracellular matrix regulation might be the contributing factors. Further research is warranted to explore clinical implications of these findings.

Endosaccular flow disruption with the Contour Neurovascular System: angiographic and clinical results in a single-center study of 60 unruptured intracranial aneurysms

BACKGROUND

The Contour Neurovascular System is a novel device designed to treat intracranial aneurysms by intrasaccular flow disruption. We report our experience and mid-term follow-up in a series of patients treated with the Contour.

METHODS

The patients were divided into an intention to treat and a per protocol population, the latter defined by the successful implantation of the Contour device. The intention to treat population included 53 patients (30 women, mean age 56 years) with 60 unruptured intracranial aneurysms (53 in the anterior circulation and seven in the posterior circulation). There was clinical and angiographic follow-up immediate postoperatively and at 24 hours, 3 months and 1 year using the Raymond-Roy classification and the O'Kelly-Marotta grading scale.

RESULTS

The Contour was successfully implanted in 54/60 (90%) aneurysms. With regard to the angiographic follow-up, there was adequate occlusion (defined as complete occlusion or presence of a neck remnant) in 31.5% of 54 aneurysms immediately postoperatively, 62.3% (in 53/54 aneurysms) at 24 hours, 81.4% (in 43/54 aneurysms) at 3 months, and 89.3% (in 28/54 aneurysms) at 1 year. Technical complications in 60 aneurysms of the intention to treat population included two (3.3%) inadvertent detachments of the device. Thromboembolic events were observed in four of the 60 aneurysms (6.7%), with no clinical symptoms in three patients and transient morbidity in one (1.7%). No aneurysm bleeding was observed and no patient was retreated during the 1-year follow-up period. There was no permanent morbidity or mortality.

CONCLUSIONS

The Contour device is effective and safe in the treatment of intracranial aneurysms. However, more experience and long-term follow-up are needed.

The incidence and predictors of in-stent stenosis after pipeline flow-diverter stenting for intracranial aneurysm treatment

Background and purpose

Data on in-stent stenosis (ISS) following the flow diverter (FD) implantation method are scarce and inconsistent. In the present study, we sought to determine the incidence of ISS and identify the factors that predict its severity via the use of ordinal logistic regression.

Methods

A retrospective review of our center's electronic database was conducted to identify all patients with intracranial aneurysms (IAs) who received pipeline embolization device (PED) implantation between 2016 and 2020. Patient demographics, aneurysm characteristics, procedural information, and clinical and angiographic outcomes were reviewed. ISS was quantitatively assessed on angiographic follow-ups and graded as mild (<25%), moderate (25-50%), or severe (>50%). Ordinal logistic regression was conducted to determine the predictors of stenosis severity.

Results

A total of 240 patients with 252 aneurysms treated in 252 procedures were enrolled in this study. ISS has been detected in 135 (53.6%) lesions, with a mean follow-up time of 6.53 ± 3.26 months. The ISS was mild in 66 (48.9%) cases, moderate in 52 (38.5%) cases, and severe in 17 (12.6%) cases. All patients were asymptomatic, except for two of them with severe stenosis who presented with symptoms of acute cerebral thrombosis. Ordinal logistic regression identified that younger age and a longer procedure duration were independent predictors of a higher likelihood of ISS.

Conclusion

ISS is a common angiographic finding after PED implantation for IAs and is presented as a largely benign course through long-term follow-up. Patients who were younger in age and had a longer procedure duration were found to be at a greater risk of developing ISS.

Distal Flow Diversion with Anti-Thrombotically Coated and Bare Metal Low-Profile Flow Diverters—A Comparison

Background and purpose: The establishment of low-profile flow diverting stents (FDS), for example, the Silk Vista Baby (SVB) and the p48MW, facilitated endovascular treatment of peripheral cerebral aneurysms. This study therefore aims to compare the performance and outcomes of the SVB with those of the p48MW HPC, with a special focus on hemodynamic aspects of peripheral segments and bifurcations. Materials and methods: The study cohort comprises 108 patients, who were either treated with the SVB or the p48MW HPC between June 2018 and April 2021. Results: Sixty patients received a SVB and forty-eight patients a p48MW HPC. The SVB was used predominantly in the AcomA-complex, and the p48MW HPC in the MCA bifurcation. Immediately after implantation, significant hemodynamic downgrading (OKM A2-A3, B1-B3, C3) was achieved in 60% in the SVB group vs. 75.1% in the p48MW HPC group. At the second follow-up, after an average of 8.8 and 10.9 months, respectively, OKM D1 was observed in 64.4% of the SVB group vs. 27.3% in the p48MW HPC group. Only 1.7% vs. 6.8% of the aneurysms remained morphologically unaltered (OKM A1). Adverse events with persisting neurologic sequalae at last follow-up were largely comparable in both groups (5.0% vs. 4.2%). Conclusion: Immediately after implantation, the p48MW HPC had a more profound hemodynamic impact than the SVB; however, early complete occlusions were achieved in a greater proportion of lesions after implantation of the uncoated SVB.

Ticagrelor versus clopidogrel dual antiplatelet therapy for unruptured intracranial aneurysms treated with flowdiverter

BACKGROUND AND PURPOSE

Antiplatelet therapy (APT) is a key element limiting the risk of thromboembolic events (TEE) in neuroendovascular procedures, including aneurysm treatment with flowdiverter. Clopidogrel combined with aspirin is the mostly reported dual APT (DAPT). However, resistance phenomenon and intraindividual efficacy fluctuation are identified limitations. In recent years, ticagrelor has been increasingly used in this indication. We compared these two DAPT regimens for intracranial aneurysm treated with flowdiverter.

METHODS

We conducted a multicentric retrospective study from prospectively maintained databases in two high volume centers extracting consecutive patients presenting unruptured intracranial aneurysm treated with flowdiverter and receiving DAPT (May 2015 to December 2019).  Two groups were compared according to their DAPT regimen: "ticagrelor+aspirin" and "clopidogrel+aspirin". Clopidogrel group was systematically checked with platelet test inhibition before endovascular procedure. The primary endpoint was composite, defined as any thrombo-embolic event (TEE) or major hemorrhagic event occurring the first 6 months during and after embolization RESULTS: 260 patients met our inclusion criteria. Baseline patients and aneurysms characteristics were comparable between groups, except for aneurysm location, median size and pre-treatment modified Rankin scale. No significant difference was observed regarding the primary composite outcome: 11.5% (12/104) in the ticagrelor group versus 10.9% (17/156) in the clopidogrel group (p = 1.000). There was also no significant difference in secondary outcomes including TEE (10.5 vs 9.0%; p = 0.673), major hemorrhage (0.9 vs 1.2%; p = 0.651) and clinical outcome (at least 1-point mRS worsening during follow up: 6.7% vs 8.3%; p = 0.813).

CONCLUSION

First-line DAPT with ticagrelor+aspirin seems as safe and effective as clopidogrel+aspirin regimen.

The DERIVO®2 Embolization Device in the treatment of ruptured and unruptured intracranial aneurysms: A multicenter analysis

BACKGROUND

Flow diverters are an increasingly used treatment option for intracranial aneurysms. A recent addition to the European market is the DERIVO®2 Embolization Device (DED2), promising improved radiopacity. We aimed to assess the safety and efficacy of the DED2 regarding angiographic and clinical outcomes in ruptured and unruptured cerebral aneurysms.

METHODS

We performed a multicenter trial at six interventional centers. Data were prospectively collected and all patients treated with the DED2 were included. The primary endpoint was angiographic aneurysm occlusion at 6 months as assessed by the O'Kelly Marotta (OKM) grading scale with a favorable outcome definition of OKM C + D. Clinical outcome was evaluated according to the modified Rankin scale (mRS).

RESULTS

Between August 2020 and July 2021, 37 patients were treated with the DED2 and were included in our analysis. Five patients presented with ruptured aneurysms. Median age was 60 years, 27 patients were female, and 10 male. Median mRS was 0 (range 0-4). Mean aneurysm size was 8.9 ± 7.1 mm with a mean neck size of 6.5 ± 6.1. The DED2 fully opened at deployment in all cases. Clinical follow-up was available for 30 patients (81%). Twenty-five (83%) had an mRS of 0 or 1. Three patients with ruptured aneurysms died during the follow-up period. No treatment-related major morbidity was observed. Follow-up imaging was available in 27 (90%) patients, with 23 patients (85%) showing satisfactory aneurysm occlusion OKM grade C-D.

CONCLUSION

In this small cohort, the DED2 provided safe and effective treatment of ruptured and unruptured intracranial aneurysms.

Tortuosity of parent artery predicts in-stent stenosis after pipeline flow-diverter stenting for internal carotid artery aneurysms

Background and purpose

The relationship between the tortuosity of the parent artery and treatment outcomes is not well established. We investigate the association between parent artery tortuosity and flow diverter (FD) treatment outcomes in patients with internal carotid artery aneurysms in this study.

Methods

A retrospective review study was conducted to identify all patients with internal carotid artery aneurysms who were implanted with Pipeline embolization device (PED) between 2016 and 2020. The relationship between parent artery tortuosity and aneurysm complete occlusion (CO) and in-stent stenosis (ISS) was analyzed. The mathematical parameters “Curvature”, “torsion”, and “DM” extracted from the parent artery were utilized to quantify the parent artery tortuosity. A vascular narrowing of greater than 25% was categorized as ISS. Logistic regression analysis was used to identify significant independent predictors. Furthermore, we compared the performance of four machine learning algorithms and Logistic Regression model in predicting ISS.

Results

This research included 62 patients who with internal carotid artery aneurysms. In 49 (79%) cases, follow-up angiography (mean follow-up duration 11.7 ±7.3 months) revealed CO of the aneurysm. ISS was detected in 22 (35.5%) cases. According to univariate analysis, parent artery tortuosity and other variables were not associated with CO (p > 0.1). Maximum curvature (OR = 1.084; 95% CI, 1.008–1.165; p = 0.03) and DM (OR = 0.01; 95% CI, 0–0.488; p = 0.02) exhibited strong independent associations with ISS in multivariate analysis. The SVM model is superior to the conventional Logistic Regression model and the other models in predicting ISS.

Conclusions

The tortuosity of the parent artery may affect the treatment outcome of FD stenting. We found that parent artery tortuosity was associated with ISS, but not with aneurysm complete occlusion following PED stenting for internal carotid artery aneurysms in this study. Parent arteries with higher maximum curvature and lower DM were more likely to develop ISS.

Surpass Evolve Flow Diverter for the Treatment of Intracranial Aneurysm: A Systematic Review

PURPOSE

This systematic review aims to summarize the evidence investigating the effectiveness and safety of the Surpass Evolve-Flow Diverter (SE-FD) to treat brain aneurysms.

METHOD

We searched MEDLINE, EMBASE, CINAHL, Web of Science, and Cochrane Library from January 2019 to 29 March 2022. Terms related to the "intracranial aneurysm" and "surpass evolve flow diverter" concepts were used to search the databases; Medical Subject Headings (MeSH) and reference hand search were also utilized.

RESULTS

The searches primarily identified 1586 documents. A total of five studies (four case series and one cohort) were included in this review. In the included studies, 192 (74 male and 118 females) patients with 198 aneurysms were involved. In total, 153 SE-FDs were used to treat 145 aneurysms. Complete occlusion was achieved in 69/145 (48%) cases and near-complete occlusion in 24/145 (17%) cases from aneurysms treated with SE-FD. Reported postoperative complications included stent thrombosis (n = 4 patients), hemorrhage (n = 5 patients), ischemia (n = 9 patients), and neurological complications (n = 12 patients). In total, four deaths were reported with only one related to the SE-FD procedure.

CONCLUSION

The results of this review are based on observational data, due to the absence of clinical trials. The findings of the included studies suggest that the effectiveness of the SE-FD procedure is lower than previous FDs but the safety is similar. The included studies also suggested that SE-FD has navigability and resistance to twisting, which makes the procedure an easier method to treat aneurysms that are proximal and distal to the circle of Willis deployment. This review highlights the urgency to conduct clinical trials to confirm these suggestions.

The Pennsylvania Postmarket Multicenter Experience With Flow Redirection Endoluminal Device

BACKGROUND

The flow redirection endoluminal device (FRED) is a novel self-expanding double-layer nitinol braided flow diverter that recently received FDA approval. However, early postmarket studies from the United States are lacking.

OBJECTIVE

To report our short-term multicenter experience.

METHODS

Series of consecutive patients undergoing FRED treatment for intracranial aneurysms were queried from prospectively maintained registries at 4 North-American Centers in Pennsylvania (February 2020-June 2021). The pertinent baseline demographics, aneurysmal characteristics, and procedural outcomes were collected and analyzed, with primary outcome of aneurysmal occlusion and secondary outcome of safety and complications.

RESULTS

Sixty-one patients (median age 58 years, 82% female) underwent 65 FRED treatment procedures for 72 aneurysms. Most (86.1%) of the aneurysms were unruptured; 80.5% were saccular in morphology, and 87.5% were located along the internal carotid artery, with a median size of 7.1 mm (IQR 5.2-11.9 mm). Radiographic follow-up was available in 86.1% of the aneurysms, showing complete occlusion in 74.2% (80% in catheter angiography-only group), and near-complete occlusion in 11.3% of the cases (median 6.3 months), with 2.8% re-treated. Permanent ischemic complications were encountered in 2.8% of the cases, with no procedural mortality. A modified Rankin Scale of 0 to 2 was documented in 98.1% of the patients at the last clinical follow-up (median 6.1 months).

CONCLUSION

The results of the early postmarket experience with the FRED device show reasonable safety and adequate aneurysmal occlusion rates comparable with other flow diverters. However, more extensive multicenter studies with more extended follow-up data are needed to assess the long-term safety and durability of the device.

Comparison of the Pipeline embolisation device alone or combined with coiling for treatment of different sizes of intracranial aneurysms

Objectives

The aim of this study was to compare complications and outcomes between intracranial aneurysms treated with the Pipeline embolisation device (PED) alone or with PED combined with coiling for different-sized aneurysms.

Method

Patients with aneurysms treated by PED were collected from the PED in China postmarket multicentre registry study. We performed a propensity match analysis to compare the efficacy and safety between PED alone and PED combined with coiling treatment, and then aneurysms were organised into three groups based on their size: small (≤7 mm), medium (≤15 mm to >7 mm) and large/giant (>15 mm). Complications and aneurysm occlusion rates in the aneurysm size groups were compared between PED alone and PED combined with coiling patients.

Result

A total of 1171 patients with 1322 aneurysms were included. All patients received clinical follow-up, while angiographic follow-up was available in 967 aneurysms. For small aneurysms, there was no difference in the aneurysm occlusion rate between two groups (79.1% vs 88.4%, respectively), while there was a significant increase in the ischaemic complication rate (8.3% vs 19.3%, respectively, p=0.0001). For medium and large/giant saccular aneurysms, PED combined with coiling significantly improved the occlusion rate (medium aneurysms: 74.7% vs 88.8%, respectively, p<0.0001; large/giant saccular aneurysms: 72.9% vs 86.9%, respectively, p=0.018), while there were no differences in the total complication rate. For large/giant non-saccular aneurysms, two groups showed no differences.

Conclusion

Use of the PED with adjunctive coils can significantly improve the occlusion rate of medium aneurysms, without increasing the total complication rate.

Critical Angiographic and Sonographic Analysis of Intra Aneurysmal and Downstream Hemodynamic Changes After Flow Diversion

Introduction

Successful treatment of intracranial aneurysms after flow diversion (FD) is dependent on the flow modulating effect of the device. We aimed to investigate the intra-aneurysmal and parent vessel hemodynamic changes, as well as the incidence of silent emboli following treatment with various FD devices.

Methods

We evaluated the appearance of the eclipse sign in nine distinct phases of cerebral angiography before and immediately after FD placement in correlation with aneurysm occlusion. Angiographic and clinical data of consecutive procedures were analyzed retrospectively. Patients who had successful FD procedure without adjunctive coiling, visible eclipse sign on post embolization angiography, and reliable follow-up angiographic data were included in the analysis. Detailed analysis of hemodynamic data from transcranial doppler after FD was performed in selected patients, such as monitoring for silent emboli.

Results

Among all patients (N = 65) who met inclusion criteria, complete aneurysm occlusion at 12 months was achieved in 89% (58/65). Eclipse sign prior to FD was observed in 42% (27/65) with unchanged appearance in 4.6% (3/65) of the treated patients. None of these three patients achieved complete aneurysm occlusion. Among all analyzed variables, such as aneurysm size, device type used, age, and appearance of the eclipse sign pre- and post-FD, the most reliable predictor of permanent aneurysm occlusion at 12 months was earlier, prolonged, and sustained eclipse sign visibility in more than three angiographic phases in comparison to the baseline (p &lt; 0.001). Elevation in flow velocities within the ipsilateral vascular territory was noted in 70% (9/13), and bilaterally in 54% (7/13) of the treated patients. None of the patients had silent emboli.

Conclusions

Intra-aneurysmal and parent vessel hemodynamic changes after FD can be reliably assessed by the cerebral angiography and transcranial doppler with important implications for the prediction of successful treatment.

Vascular Response on a Novel Fibrin-Based Coated Flow Diverter

Purpose

Due to thromboembolic complications and in-stent-stenosis after flow diverter (FD) treatment, the long-term use of dual antiplatelet treatment (DAPT) is mandatory. The tested nano-coating has been shown to reduce material thrombogenicity and promote endothelial cell proliferation in vitro. We compared the biocompatibility of coated (Derivo Heal) and non-coated (Derivo bare) FDs with DAPT in an animal model.

Methods

Derivo® bare (n = 10) and Derivo® Heal (n = 10) FD were implanted in the common carotid arteries (CCAs) of New Zealand white rabbits. One additional FD, alternately a Derivo bare (n = 5) or Derivo Heal (n = 5), was implanted in the abdominal aorta (AA) for assessment of the patency of branch arteries. Histopathological examinations were performed after 28 days. Angiography was performed before and after FD implantation and at follow-up.

Results

Statistical analysis of the included specimens showed complete endothelialization of all FDs with no significant differences in neointima thickness between Derivo® bare and Derivo® Heal (CCA: p = 0.91; AA: p = 0.59). A significantly reduced number of macrophages in the vessel wall of the Derivo Heal was observed for the CCA (p = 0.02), and significantly reduced fibrin and platelet deposition on the surface of the Derivo Heal was observed for the AA. All branch arteries of the stented aorta remained patent.

Conclusion

In this animal model, the novel fibrin-based coated FD showed a similar blood and tissue compatibility as the non-coated FD.

Hemodynamic analysis and implantation strategies of delayed intracranial aneurysm rupture after flow diverter treatment

BACKGROUND

Delayed aneurysm rupture after flow diverters (FDs) is a serious complication which mechanism remains unclear. The hemodynamics of FDs with proximal or distal densification implantation strategies have rarely been reported. In this study, we investigated not only the hemodynamic factors involved in postoperative rupture, but also the hemodynamic effects of different FDs implantation strategies on avoiding this complication.

METHODS

We selected 2 internal carotid artery (ICA) aneurysms with similar morphological characteristics, both of which were treated with FDs but had opposite therapeutic outcomes (Case 1, ruptured after FD treatment; Case 2, recovered). The FDs strategies we designed were strategy A [with homogeneous 30% metal coverage ratio (MCR)], strategy B (with distal densification of 40% and proximal 30% MCR) and strategy C (with proximal densification of 40% and distal 30% MCR). Virtually FDs deployment and computational fluid dynamics (CFD) method were performed to simulate FDs implantation strategies and analyze the hemodynamics associated with postoperative rupture.

RESULTS

After FDs implantation, the velocity of blood entering the aneurysm decreased (Case 1, 25.4%; Case 2, 30.6%), but the inflow jet impingement still existed in Case 1. The overall WSS decreased similarly in both cases, but the high WSS region hardly diminished in Case 1. For overall wall pressure, Case 2 decreased slightly but increased in Case 1. Of the three FDs implantation strategies, strategy C had the best hemodynamic effects, including the maximum blood velocity reduction and a tendency to form a more stable flow pattern, the maximum reduction rate of overall WSS and the effective diminish of high WSS area as well as the overall decrease of wall pressure.

CONCLUSIONS

Not significant decrease of blood flow velocity entering the aneurysm adding persistent impact of inflow jet impingement, high WSS area that did not diminish and abnormal increase of pressure on the aneurysm wall may be causative of postoperative rupture and bleeding of ICA aneurysms. In addition, the hemodynamic effects were favorable when the FD was improved to proximal densification, which may reduce the risk of delayed aneurysm rupture following FDs treatment.

KEYWORDS

Delayed rupture; flow diverter (FD); computational fluid dynamics (CFD); intracranial aneurysm (IAs); internal carotid artery (ICA).

Flow diversion for internal carotid artery aneurysms with compressive neuro-ophthalmologic symptoms: clinical and anatomical results in an international multicenter study

BACKGROUND

Scientific data on the safety and efficacy of flow diverter stents (FDS) for the treatment of unruptured internal carotid artery (ICA) aneurysms with compressive neuro-ophthalmological symptoms are scarce. We studied this subject in a retrospective international multicenter series, pooling data of 9 tertiary care neurointerventional departments.

OBJECTIVE

To investigate, in a retrospective, multicentric cohort of patients presenting with visual or oculomotor symptoms attributed to a compressive carotid artery in an unruptured intracranial aneurysm, the safety and efficacy profiles of FDS, by analyzing neuro-opthalmologic symptom evolution following FDS placement, complications, and aneurysm obliteration rates.

METHODS

All patients treated since 2015 with a FDS for an unruptured aneurysm of the ICA with signs of compressive cranial nerve symptoms (CN II, III, IV, VI) were included.

RESULTS

We treated 55 patients with 55 aneurysms; 21 (38.2%) patients had oculomotor and 15 (27.3%) visual symptoms only; 19 (34.5%) presented with a combination of both. Treatment-related morbidity/mortality occurred in 7.2% and 3.6%, respectively. At last imaging follow-up (13.1±10.5 months) rates of complete aneurysm occlusion, neck remnant, and aneurysm remnant were 72%, 14%, and 14%, respectively. At last clinical follow-up after 13±10.5 months, 19/51 (37.3%) patients had recovered completely and 18/51 (35.3%) had recovered at least partially from their neuro-ophthalmological symptoms. In multivariable models, a longer delay between symptom onset and treatment was associated with higher odds for incomplete recovery and lower odds for any improvement (aOR 1.03 (95% CI 1.01 to 1.07), p=0.047 and 0.04 (0-0.81), p=0.020). Incomplete recovery was independently associated with older age and fusiform aneurysms.

CONCLUSION

FDS are effective to treat patients with compressive aneurysms of the ICA causing neuro-ophthalmological symptoms, especially when treatment is initiated early after symptom onset, and aneurysm occlusion is adequate. However, serious complications are not rare.

Safety and Efficacy of Coils in Conjunction With the Pipeline Flex Embolization Device for the Treatment of Cerebral Aneurysms

Background: Flow diverters (FD) have shown promising results in the treatment of intracranial aneurysms (IAs). However, there is still controversy whether pipeline flex embolization device (PED flex)-assisted coils can facilitate the curing of aneurysms. Our aim was to assess the safety and effectiveness of PED flex adjunctive with coils (PED flex + coil) in the treatment of IAs. Method: Patients who underwent PED flex treatment in combination with coiling between January 2018 and June 2020 were included in this study. The clinical and radiographic characteristics before and after treatments were retrospectively evaluated. The study cohort comprised of 125 patients with 140 IAs, which was subdivided into two subgroups: one group included patients treated only through PED alone, and the other group included patients treated through PED flex adjunctive with coil. Patient baseline characteristics, aneurysm characteristics, treatment-related factors, and outcomes were analyzed to determine the effectiveness of both techniques. Results: Aneurysms in the PED flex + coil group were larger (10.0 ± 5.8 mm, P < 0.001) and wider (7.2 ± 4.6 mm, P = 0.002) compared with those in the PED flex group. There was no statistical difference in the perioperative complication rate between the two groups. The overall complete occlusion rate was 75.7% at 6.2 months, with 71.7% at 6.2 ± 1.7 months in the PED flex group and 85.4% at 6.2 ± 1.8 months in the PED flex + coil group, respectively. A higher percentage of satisfactory angiography results was found in the PED flex + coil group during follow-up (92.7 vs. 78.8%, P = 0.047). Conclusion: PED flex placement with adjunctive coil embolization represents a safe alternative option for the treatment of IAs. In these cases, coil embolization increases the occlusion rate in PED flex-treated patients without increasing the periprocedural complications.

Results of watchful waiting of unruptured intracranial aneurysms in a Western patient population: a single-center cohort

BACKGROUND

The natural history of unruptured intracranial aneurysms (UIAs) in Western populations is still debated, especially for those <7 mm. Reporting data of a large single-center cohort managed with watchful waiting is therefore interesting.

METHODS

From January 2011 to June 2019, 662 UIAs were followed up by yearly MR angiography. Morphologically stable UIAs were managed conservatively while unstable UIAs were offered treatment. The patients' clinical and radiological data were analyzed retrospectively.

RESULTS

UIAs were ≤4 mm in 60%, 4.1-7.0 mm in 33%, and >7 mm in 7%. They were located on the anterior circulation in 90% of cases. The mean follow-up duration was 51.32 months for a total of 2831 aneurysm-years. During follow-up, 37 UIAs (5.5%) were treated because of an increase in size, and 8 UIAs were treated because of patient decision. Three aneurysms ruptured during follow-up for an annual risk of rupture of 0.1% (95% CI 0% to 0.24%). No risk factors for rupture were identified. The three ruptured cases made an excellent recovery. During follow-up, annual mortality from unrelated causes was 0.8% (95% CI 0.51% to 1.18%).

CONCLUSIONS

This single-center cohort evaluated our watchful waiting policy applied in two-thirds of all incidental UIAs. Morphological change of UIAs during follow-up led to treatment in 5.5% of cases. With such a management paradigm, we found a low rupture rate in these selected UIAs and the mortality was unrelated to aneurysms.

Cost-Effectiveness Analytic Comparison of Neuroimaging Follow-Up Strategies After Pipeline Embolization Device Treatment of Unruptured Intracranial Aneurysms

BACKGROUND

Flow diversion via a Pipeline embolization device (PED [Medtronic, Dublin, Ireland]) is one of the established modalities for the treatment of unruptured intracranial aneurysms that require a robust follow-up regimen. However, to date, no consensus has been reached regarding the optimal imaging modality and timing intervals for such a strategy. We studied the cost-effectiveness of different neuroimaging follow-up strategies after flow diversion with the PED.

METHODS

A decision-analytical study using Markov modeling was performed to compare 5 commonly used multistep follow-up strategies with different combinations of digital subtraction angiography (DSA) and magnetic resonance angiography (MRA): 1) DSA at 6 months and MRA at 12 and 24 months; 2) DSA at 6, 12, and 24 months; 3) MRA at 6, 12, and 24 months; 4) DSA at 6 and 12 months and MRA at 24 months; and 5) DSA at 12 months and MRA at 24 months. The input parameters were mainly collected from the latest meta-analysis, and 1-way, 2-way, and probabilistic sensitivity analyses were conducted to assess the robustness of our model.

RESULTS

Strategy 5, incorporating DSA at 12 months and MRA at 24 months, was the most cost-effective strategy for >99% of the 10,000 iterations in the probabilistic sensitivity analysis at a willingness-to-pay threshold of $100,000/quality-adjusted life-year. The result remained robust in the 1- and 2-way sensitivity analyses.

CONCLUSIONS

Given the current data, delayed imaging follow-up at 1 year with DSA and 2 years with MRA after PED treatment of unruptured intracranial aneurysms is more cost-effective than early follow-up at 6 months.

Repeat Flow Diversion for Cerebral Aneurysms Failing Prior Flow Diversion: Safety and Feasibility From Multicenter Experience

BACKGROUND AND PURPOSE

Aneurysmal persistence after flow diversion (FD) occurs in 5% to 25% of aneurysms, which may necessitate retreatment. There are limited data on safety/efficacy of repeat FD-a frequently utilized strategy in such cases.

METHODS

A series of consecutive patients undergoing FD retreatment from 15 centers were reviewed (2011-2019), with inclusion criteria of repeat FD for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months post-retreatment imaging. The primary outcome was aneurysmal occlusion, and secondary outcome was safety. A multivariable logistic regression model was constructed to identify predictors of incomplete occlusion (90%-99% and <90% occlusion) versus complete occlusion (100%) after retreatment.

RESULTS

Ninety-five patients (median age, 57 years; 81% women) harboring 95 aneurysms underwent 198 treatment procedures. Majority of aneurysms were unruptured (87.4%), saccular (74.7%), and located in the internal carotid artery (79%; median size, 9 mm). Median elapsed time between the first and second treatment was 12.2 months. Last available follow-up was at median 12.8 months after retreatment, and median 30.6 months after the initial treatment, showing complete occlusion in 46.2% and near-complete occlusion (90%-99%) in 20.4% of aneurysms. There was no difference in ischemic complications following initial treatment and retreatment (4.2% versus 4.2%; P>0.99). On multivariable regression, fusiform morphology had higher nonocclusion odds after retreatment (odds ratio [OR], 7.2 [95% CI, 1.97-20.8]). Family history of aneurysms was associated with lower odds of nonocclusion (OR, 0.18 [95% CI, 0.04-0.78]). Likewise, positive smoking history was associated with lower odds of nonocclusion (OR, 0.29 [95% CI, 0.1-0.86]). History of hypertension trended toward incomplete occlusion (OR, 3.10 [95% CI, 0.98-6.3]), similar to incorporated branch into aneurysms (OR, 2.78 [95% CI, 0.98-6.8]).

CONCLUSIONS

Repeat FD for persistent aneurysms carries a reasonable success/safety profile. Satisfactory occlusion (100% and 90%-99% occlusion) was encountered in two-thirds of patients, with similar complications between the initial and subsequent retreatments. Fusiform morphology was the strongest predictor of retreatment failure.

Retreatment of previously treated intracranial aneurysm: Procedural complications and risk factors for complications

OBJECTIVE

Intracranial aneurysm (IA) is a frequent vascular malformation that can be managed by endovascular treatment (EVT) or microsurgery. A previously treated IA can recanalize, which may require further treatment. The aim of our study was to evaluate procedural complications related to IA retreatment and their risk factors.

METHODS

All patients retreated for IA between 2007 and 2017 in 4 hospitals were included. We retrospectively reviewed the frequency of procedural complications of IA retreatment, defined as death or≥1-point increase in modified Rankin score 24h after the procedure. We then screened for risk factors of procedural complications by comparing the characteristics of patients with and without complications.

RESULTS

During the inclusion period, 4,997 IAs were treated in our 4 institutions. Of these, 237 (4.7%) were retreated. 29 (12.2%) had≥1 procedural complication. However, severe complications, defined as death or dependency at 1 month, occurred only in 3 patients (1.3%). The only risk factor for complications was microsurgical clipping as retreatment.

CONCLUSIONS

Procedural complications during IA retreatment were frequent but, in most cases, retreatment did not lead to death or severe disability. The only risk factor for complications of IA retreatment was clipping as retreatment. However, the design of the study did not allow any conclusion to be drawn as to the optimal means of aneurysm retreatment, and further studies are needed.

A novel score for evaluating cerebral aneurysms treated with flow diversion: 4F-flow diversion predictive score

Background and purpose

Although grading scales for angiography outcomes following cerebral aneurysm treatment with flow diversion have been published, physicians have not widely adopted these scales in practice. The aim of this study is to propose and validate a novel Flow diversion Predictive Score (4F-FPS) grading scale based on previously established scales that is simple and reliable.

Methods

We retrospectively analyzed consecutive patients who underwent endovascular treatment for cerebral aneurysms with flow diversion between January 2014 and September 2019. The included patients were randomly divided into the derivation and validation group in a 70/30 ratio, respectively. Aneurysms were classified as incomplete or complete occlusion based on final angiography outcomes. 4F-FPS was derived to predict aneurysm occlusion from multivariate logistic regression analyses in the derivation group and validated with previously published grading scales in the validation group.

Results

Overall, 662 patients [mean age, 53.8 years; 72.5% (480/662) female] with 662 aneurysms treated with the Pipeline^TM flow diverter were included [69.9% (463/662) derivation group, 30.1% (199/662) validation group]. The incidence of aneurysm occlusion was 82.7%. 4F-FPS demonstrated significant discrimination in 10-fold cross validation [mean receiver operating characteristic (ROC) area, 0.862 ± 0.055] and calibration (Cox & Snell R ², 0.251; Nagelkerke R ², 0.413) in the derivation group. The ROC area of 4F-FPS score in both the derivation and validation groups is the largest compared with previously published grading scales/scores (p < 0.05), which shows better sensitivity and specificity. The 4F-FPS score showed excellent prediction, discrimination, and calibration properties.

Conclusion

The 4F-FPS score is a simple and reliable tool to predict angiography outcome after flow diversion treatment. If widely adopted, it may provide a common language to be used in future reporting of flow diversion results for clinical trials and daily practice.

Clinical trial registration

http://www.clinicaltrials.gov. Unique identifier: NCT03831672.

Timing and Spectrum of Neurological Complications After Flow Diverter Implantation for Intracranial Aneurysms

Background and Purpose: The aim of this study was to characterize neurological complications after flow diverter (FD) treatment on a long follow-up cohort and identify predictive factors associated with these complications.

Methods: This study was conducted on a monocentric cohort of patients treated for intracranial aneurysms by FD.

Results: Between September 2008 and July 2018, 413 patients were treated for 514 aneurysms: 18% of the patients presented with at least one neurological complication during a median follow-up of 446 days (IQR 186–1,210). Sixty-one patients presented with ischemic complications, 13 with hemorrhagic ones and 10 with compressive processes. Among 89 neurological complications 64.5% were peri-operative (occurring within the 30 days following the procedure) and 35.5% were delayed after 1 month.

Conclusions: Overall, neurological complications after FD implantation were overrepresented by cerebrovascular ischemic events occurring during the peri-operative period, but also in a delayed manner after 1 year. Long-term follow-up is relevant after aneurysm intervention using FD.

Pipeline Embolization Device for Intracranial Aneurysms in a Large Chinese Cohort: Complication Risk Factor Analysis

During intracranial aneurysm embolization with the Pipeline embolization device (PED), ischemic and hemorrhagic complications have been observed in cases among Western populations. The postmarket multicenter registry study on the embolization of intracranial aneurysms with the PED in China, i.e., the PLUS study, was performed to assess real-world predictors of complications and functional outcomes in patients treated with the PED in a Chinese population. All patients with intracranial aneurysms who underwent embolization using the PED between November 2014 and October 2019 across 14 centers in China were included. The study endpoints included preoperative and early postoperative (< 30 days) functional outcomes (modified Rankin scale [mRS] scores) and complications related to PED treatment at early postoperative and follow-up time points (3-36 months). Multivariate analysis was performed to identify risk factors for complications. A total of 1171 consecutive patients (mean age, 53.9 ± 11.4; female, 69.6% [813/1171]) with 1322 aneurysms were included in the study. Hypertension, basilar artery aneurysms, and successful deployment after adjustment or unsuccessful device deployment were found to be independent predictors of ischemic stroke, while the use of the Flex PED and incomplete occlusion immediately after treatment were protective factors. An aneurysm size > 10 mm, distal anterior circulation aneurysms, and adjunctive coiling were found to be independent predictors of delayed aneurysm rupture, distal intraparenchymal hemorrhage, and neurological compression symptoms, respectively. The rate of PED-related complications in the PLUS study was similar to that in Western populations. The PLUS study identified successful deployment after adjustment or unsuccessful device deployment and the degree of immediate postoperative occlusion as novel independent predictors of PED-related ischemic stroke in a Chinese population. ClinicalTrial.gov Identifier: NCT03831672.

CD31 Mimetic Coating Enhances Flow Diverting Stent Integration into the Arterial Wall Promoting Aneurysm Healing

BACKGROUND AND PURPOSE

Beyond aneurysmal occlusion, metallic flow diverters (FDs) can induce an adverse endovascular reaction due to the foreignness of metal devices, hampering FD endothelialization across the aneurysm neck, and arterial healing of intracranial aneurysms. Here, we evaluated the potential benefits of an FD coating mimicking CD31, a coreceptor critically involved in endothelial function and endovascular homeostasis, on the endothelialization of FDs implanted in vivo.

METHODS

Nitinol FD (Silk Vista Baby) and flat disks were dip-coated with a CD31-mimetic peptide via an intermediate layer of polydopamine. Disks were used to assess the reaction of endothelial cells and blood elements in vitro. An aneurysm rabbit model was used to compare in vivo effects on the arterial wall of CD31-mimetic-coated (CD31-mimetic, n=6), polydopamine-coated (polydopamine, n=6), and uncoated FDs (bare, n=5) at 4 weeks post-FD implantation. In addition, long-term safety was assessed at 12 weeks.

RESULTS

In vitro, CD31-mimetic coated disks displayed reduced adhesion of blood elements while favoring endothelial cell attachment and confluence, compared to bare and polydopamine disks. Strikingly, in vivo, the neoarterial wall formed over the CD31-mimetic-FD struts at the aneurysm neck was characteristic of an arterial tunica media, with continuous differentiated endothelium covering a significantly thicker layer of collagen and smooth muscle cells as compared to the controls. The rates of angiographic complete occlusion and covered branch arterial patency were similar in all 3 groups.

CONCLUSIONS

CD31-mimetic coating favors the colonization of metallic endovascular devices with endothelial cells displaying a physiological phenotype while preventing the adhesion of platelets and leukocytes. These biological properties lead to a rapid and improved endothelialization of the neoarterial wall at the aneurysm neck. CD31-mimetic coating could therefore represent a valuable strategy for FD biocompatibility improvement and aneurysm healing.

Possibility of Worsening Flow Diversion Effect Due to Morphological Changes of a Stented Artery With Multiple Overlapping Stents for Partially Thrombosed Vertebral Artery Aneurysms

Background: Morphological changes of a stented artery can cause a flow diversion effect to reduce intra-aneurysmal flow; however, there is a potential for the negative effect of increased intra-aneurysmal flow. We present cases with multiple overlapping stents for a partially thrombosed vertebral artery aneurysm and characterize the hemodynamic properties of a recurrent case by focusing on the morphological changes of the stented artery.

Methods: Between October 2017 and April 2019, four consecutive cases of symptomatic unruptured large and giant partially thrombosed vertebral artery aneurysms were treated with multiple overlapping low-profile visualized intraluminal support stents and no coils. Both angiographic and clinical outcomes were assessed. Computational fluid dynamics analysis was performed to clarify hemodynamic features. The degree of pressure elevation was calculated as the pressure difference (Pd). Wall shear stress (WSS) was also calculated.

Results: In three of the four cases, successful flow reduction was achieved with no morphological change of the stented arteries. The patients' symptoms were gradually improved. The remaining case required additional stents after the initial treatment. In the recurrent case, Pd was noticeably elevated at the aneurysm neck after treatment, and WSS was generally increased in the area due to altered blood flow into the aneurysm dome caused by morphological changes of the stented artery.

Conclusion: Overlapping stents can be used for the treatment of large and giant thrombosed vertebral artery aneurysms with flow diversion effect; however, morphological changes of the stented artery requires careful attention as it may lead to an increase in the intra-aneurysmal flow, causing negative outcomes.

Pipeline Embolization device for intracranial aneurysms in a large Chinese cohort: factors related to aneurysm occlusion

Background and Purpose:

The Pipeline Embolization Device (PED, Covidien/Medtronic) is widely used to treat intracranial aneurysms. This PED in China post-market multi-center registry study (PLUS) investigated safety and effectiveness of the PED for intracranial aneurysms in the Chinese population.

Methods:

This was a panoramic, consecutive, real-world cohort registry study. Patients treated with PED with or without coils between November 2014 and October 2019 at 14 centers in China were included, and those treated by parent vessel occlusion or other stents were excluded. Study outcomes included angiographic evaluation of aneurysm occlusion, complications, in-stent stenosis, and predictors of aneurysm occlusion. A central committee reviewed all imaging and endpoint events.

Results:

In total, 1171 patients with 1322 intracranial aneurysms were included. The total occlusion rate was 81.4% (787/967) at mean follow-up of 8.96 ± 7.50 months, with 77.1% (380/493) occlusion in the PED alone and 85.9% (407/474) in the PED plus coiling group. On multi-variate analysis, female sex, hyperlipidemia, vertebral aneurysms, PED plus coiling, and blood flow detained to venous phase were significant predictors of aneurysm occlusion. In posterior circulation cohort, there was no variable associated with aneurysm occlusion. In-stent stenosis predictors included current smoking and cerebral sclerosis/stenosis.

Conclusion:

In the largest series on PED of multi-center date of China, data suggest that treatment with the flow-diverting PED in intracranial aneurysms was efficacious. The treatment of PED combined coiling and blood flow detained to venous phase after PED implant were associated with aneurysmal occlusion. The occlusion rate of vertebral aneurysms was higher than other location aneurysms.

Clinical Trial Registration:

ClinicalTrials.gov identifier: NCT03831672.

Outcome of flow diverter placement for intracranial aneurysm with dual antiplatelet therapy and oral anticoagulant therapy

PURPOSE

Antiplatelet therapy initiated before flow diverter placement is effective for the prevention of ischemic complications. However, the effectiveness of oral anticoagulant treatment is unclear. This retrospective study evaluated the complications and obliteration rates after flow diverter placement in patients taking anticoagulants.

METHODS

A total of 155 cases were treated by Pipeline Flex placement for unruptured large and giant cerebral aneurysms in our hospital between October 2015 and June 2019. The groups of 8 patients taking anticoagulants before operation and 147 patients not taking anticoagulants were compared.

RESULTS

Clopidogrel oral dose (P = 0.002) was significantly lower in the anticoagulant group. Delayed aneurysm rupture (P = 0.002) and additional treatment (P = 0.009) rates were significantly higher and complete obliteration rate (P = 0.011) was lower in the anticoagulant group.

CONCLUSIONS

Additional oral anticoagulant administration before flow diverter placement does not reduce ischemic complications compared to dual antiplatelet therapy, but does increase hemorrhagic complications, especially delayed aneurysm rupture. Complete obliteration of the cerebral aneurysm is difficult to achieve in patients taking anticoagulants.

Derivo embolization device in the treatment of unruptured intracranial aneurysms: a prospective multicenter study

Background

Flow diverters (FD) are used regularly for the endovascular treatment of unruptured intracranial aneurysms. We aimed to assess the safety and effectiveness of the Derivo embolization device (DED) with respect to long-term clinical and angiographic outcomes.

Methods

A prospective multicenter trial was conducted at 12 centers. Patients presenting with modified Rankin Score (mRS) of 0–1, treated for unruptured intracranial aneurysms with DED were eligible. Primary endpoint was the mRS assessed at 18 months with major morbidity defined as mRS 3–5. Satisfactory angiographic occlusion was defined as 3+4 on the Kamran scale.

Results

Between July 2014 and February 2018, 119 patients were enrolled. Twenty-three patients were excluded. Ninety-six patients, 71 (74%) female, mean age 54±12.0 years, were included in the analysis. Mean aneurysm size was 14.2±16.9 mm. The mean number of devices implanted per patient was 1.2 (range 1–3). Clinical follow-up at 18 months was available in 90 (94%) patients, resulting in a mean follow-up period of 14.8±5.2 months. At last available follow-up of 96 enrolled patients, 91 (95%) remained mRS 0–1. The major morbidity rate (mRS 3–5) was 3.1% (3/96), major stroke rate was 4.2% (4/96), and mortality was 0%. Follow-up angiographies were available in 89 (93%) patients at a median of 12.4±5.84 months with a core laboratory adjudicated satisfactory aneurysm occlusion in 89% (79/89).

Conclusion

Our results suggest that DED is a safe and effective treatment for unruptured aneurysms with high rates of satisfactory occlusion and comparably low rates of permanent neurological morbidity and mortality.

Trial registration

DRKS00006103

Safety and efficacy of the Silk flow diverter: Insight from the DIVERSION prospective cohort study

BACKGROUND AND PURPOSE

Flow diverters are considered as an essential tool in the stent-based treatment of complex intracranial aneurysms. We report here a subgroup analysis of the nationwide prospective DIVERSION study to investigate the safety and efficacy of the Silk flow diverter at 12 months follow-up.

METHODS

We performed a subgroup analysis of patients included in the DIVERSION, a national prospective cohort study including all flow diverters placement between 2012 and 2014 in France, and treated with the Silk. The primary outcome was the morbi-mortality at 12 months, including death, morbidity event and aneurysm retreatment within 12 months post-treatment. All reported serious events were adjudicated by an independent Data Safety and Monitoring Board. Satisfactory occlusion was defined as 3 or 4 on Kamran's scale by an independent imaging core laboratory during follow-up.

RESULTS

A total of 102 procedures involving 101 patients (mean age±standard deviation, 54.3±13.5 years) harbouring 118 aneurysms (113/118 located in the anterior circulation; mean size 8.2±7.1mm) were included. During the 12-month follow-up, 34 (33.3%) procedures experienced at least one morbi-mortality event: 3 deaths, 27 morbidity events and 4 retreatments. Overall, 1/3 deaths and 10/27 morbidity events were related to the device and/or the procedure, leading to a specific survival rate and a specific free-morbidity survival rate at 12 months of 98.98% [95% confidence interval, 92.98%-99.86%] and 89.73% [95%CI, 81.71%-94.36%], respectively. The rate of permanent-related neurological deficit was 5.9% within 12 months. One year follow-up imaging showed satisfactory occlusion in 82.2% of cases.

CONCLUSION

Flow diversion with the Silk device has a reasonable safety and effectiveness profile for the endovascular treatment of intracranial aneurysms.