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

Open surgical treatment of basilar artery aneurysms in the interventional therapy era

PURPOSE

The purpose of this study was to describe the effectiveness and evaluation of open surgical treatment of basilar artery aneurysms in the context of interventional therapy era, including surgical clipping and blood reconstruction, by retrospectively analyzing the clinical data of basilar artery aneurysms in our center.

METHODS

Patients with basilar artery aneurysms who were treated at our center were retrospectively included according to the inclusion and exclusion criteria. The basic clinical data, surgical approach, clinical follow-up and prognosis of the enrolled patients were analyzed in detail. In this study, the mRS score was applied to assess the neurological prognosis of the patients, and the relevant data were statistically analyzed using SPSS.

RESULTS

A total of 104 eligible patients treated at our center from January 2010 to August 2023 were included in this study, of which 67 were treated by open surgery and 37 by bypass. For the 67 patients with open surgical clipping, the mean age was 60.0 (52.0, 65.0) years. The maximum diameter of the aneurysms ranged from 2.0 mm to 54.0 mm, with a mean of 13.9 (10.0, 19.0) mm. The mean follow-up time was 38 (20, 58) months. At the last follow-up, 61 (91.0%) completely obliterated aneurysms and 6 (9.0%) incompletely obliterated aneurysms were found. The prognosis was good in 59 (88.1%) patients and poor in 8 (11.9%). After surgical clipping, the difference between complete and incomplete postoperative aneurysm elimination was statistically significant between the favorable and poor prognosis groups (P < 0.001). For the 37 bypass group patients, the mean age was 52.0 (45.5, 59.0) years. The maximum diameter of the aneurysm ranged from 10.5 mm to 55.0 mm, with a mean of 28.55 ± 12.08 mm. Bypass combined with proximal occlusion was performed in 18 (48.6%) patients, and bypass only was performed in 19 (51.4%) patients. Clinical follow-up was 19.0 (10.5, 43.0) months. There were 19 (51.4%) patients with complete elimination of the aneurysm, 13 (35.1%) with incomplete elimination of the aneurysm, and 5 (13.5%) with aneurysm stabilization. The prognosis was good in 32 (86.5%) patients and poor in 5 (13.5%) patients.

CONCLUSION

Treatment of basilar artery aneurysms is challenging. In the context of the rapidly evolving interventional therapy era, open surgery including surgical clipping and bypass is an ideal option for complex basilar artery aneurysms not amenable to intervention.

Neqstent coil-assisted flow diverter (NQS) for the treatment of bifurcation aneurysms: the coil-assisted flow diversion safety and performance study (CAFI)

BackgroundThe Neqstent coil-assisted flow diverter (NQS) is a neck bridging device to facilitate coil occlusion of intracranial aneurysms. CAFI is a prospective, single-arm, multicenter study on the safety and performance of the NQS adjunctive therapy device together with platinum coils for treatment of unruptured intracranial aneurysms.

METHODS

Thirty-eight patients were enrolled. Primary endpoints were occlusion at 6 months for efficacy, and any major stroke or non-accidental death up to 30 days or major disabling stroke within 6 months for safety. Secondary endpoints were re-treatment rate, procedure time, and procedure/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee.

RESULTS

The NQS was successfully implanted in 36/38 aneurysms, 2/38 in the intention-to-treat group did not receive a NQS and were excluded from follow-up after 30 days. In the per protocol group (PP), 33/36 patients were available for angiographic follow-up. Device related adverse events were recorded in 4/38 (10.5%) patients, one hemorrhagic and three thromboembolic. In the PP group, immediate post-treatment adequate occlusion (RR1 and RR2) was seen in 9/36 (25%) and progressed to 28/36 (77.8%) at 6 months. Complete occlusion (RR1) was achieved in 29/36 (80.6%) at the last available angiogram (3/36 were post procedure). The mean procedure time was 129 min (50-300 min, median 120 min).

CONCLUSION

The NQS in conjunction with coils appears to be effective in the treatment of intracranial wide-neck bifurcation aneurysms, but its safety remains to be proved in larger series.

TRIAL REGISTRATION NUMBER

NCT04187573.

Evaluation of flow diverters for cerebral aneurysm therapy: recommendations for imaging analyses in clinical studies, endorsed by ESMINT, ESNR, OCIN, SILAN, SNIS, and WFITN

BACKGROUND

Multiple studies and meta-analyses have described the technical and clinical outcomes in large cohorts of aneurysm patients treated with flow diverters (FDs). Variations in evaluation methodology complicate making comparisons among studies, hinder understanding of the device behavior, and pose an obstacle in the assessment of further advances in FD therapy.

METHODS

A multidisciplinary panel of neurointerventionalists, imaging experts, and neuroradiologists convened with the goal of establishing consensus recommendations for the standardization of image analyses in FD studies.

RESULTS

A standardized methodology is proposed for evaluating and reporting radiological outcomes of FD treatment of intracranial aneurysms. The recommendations include general imaging considerations for clinical studies and evaluations of longitudinal changes, such as neointimal lining and stenosis. They cover standards for classification of aneurysm location, morphology, measurements, as well as the assessment of aneurysm occlusion, wall apposition, and neck coverage. These reporting standards further define four specific braid deformation patterns: foreshortening, fish-mouthing, braid bump deformation, and braid collapse, collectively termed 'F2B2'.

CONCLUSIONS

When widely applied, standardization of methods of measuring and reporting outcomes will help to harmonize the assessment of treatment outcomes in clinical studies, help facilitate communication of results among specialists, and help enable research and development to focus on specific aspects of FD techniques and technology.

Prasugrel Single Antiplatelet Therapy versus Aspirin and Clopidogrel Dual Antiplatelet Therapy for Flow Diverter Treatment for Cerebral Aneurysms: A Retrospective Multicenter Study

BACKGROUND AND PURPOSE

The optimal antiplatelet regimen after flow diverter treatment of cerebral aneurysms is still a matter of debate. A single antiplatelet therapy might be advantageous in determined clinical scenarios. This study evaluated the efficacy and safety of prasugrel single antiplatelet therapy versus aspirin and clopidogrel dual antiplatelet therapy.

MATERIALS AND METHODS

We performed a post hoc analysis of 4 retrospective multicenter studies including ruptured and unruptured aneurysms treated with flow diversion using either prasugrel single antiplatelet therapy or dual antiplatelet therapy. Primary end points were the occurrence of any kind of procedure- or device-related thromboembolic complications and complete aneurysm occlusion at the latest radiologic follow-up (mean, 18 months). Dichotomized comparisons of outcomes were performed between single antiplatelet therapy and dual antiplatelet therapy. Additionally, the influence of various patient- and aneurysm-related variables on the occurrence of thromboembolic complications was investigated using multivariable backward logistic regression.

RESULTS

A total of 222 patients with 251 aneurysms were included, 90 (40.5%) in the single antiplatelet therapy and 132 (59.5%) in the dual antiplatelet therapy group. The primary outcome-procedure- or device-related thromboembolic complications-occurred in 6 patients (6.6%) of the single antiplatelet therapy and in 12 patients (9.0%) of the dual antiplatelet therapy group (P = .62; OR, 0.712; 95% CI, 0.260-1.930). The primary treatment efficacy end point was reached in 82 patients (80.4%) of the single antiplatelet therapy and in 115 patients (78.2%) of the dual antiplatelet therapy group (P = .752; OR, 1.141; 95% CI, 0.599-2.101). Logistic regression showed that non-surface-modified flow diverters (P = .014) and fusiform aneurysm morphology (P = .004) significantly increased the probability of thromboembolic complications.

CONCLUSIONS

Prasugrel single antiplatelet therapy after flow diverter treatment may be as safe and effective as dual antiplatelet therapy and could, therefore, be a valid alternative in selected patients. Further prospective comparative studies are required to validate our findings.

Treatment of intracranial aneurysms with large-diameter (≥5.5 mm) Derivo Embolization Devices, with particular focus on 7 and 8 mm diameter devices

OBJECTIVE

There are few studies on flow diverters with diameters >5 mm. We present our preliminary experience with the 5.5-8 mm Derivo Embolization Device (DED) implants for the treatment of cerebral aneurysms.

METHODS

A consecutive series of 26 patients (median age: 60 years) treated for 32 aneurysms in 26 procedures was retrospectively analyzed for procedural characteristics, complications, and mid-term angiographic results.

RESULTS

The median aneurysm size was 10.5 mm, 2 of 30 (6%) aneurysms were ruptured and 9 (28%) had a fusiform or dissecting morphology. DED implantation was performed in the internal carotid artery in 18 of 26 (69%) procedures and in the vertebrobasilar artery in 8 (31%). Device deployment failed in 1 (4%) procedure. The 7 and 8 mm implants were successfully deployed in 5 cases. Additional balloon angioplasty or stent implantation was performed in 3 (12%) cases to improve wall apposition. Complications included 1 (4%) major stroke and 2 (8%) minor strokes. Angiographic follow up at a mean of 6 months showed complete occlusion in 8 of30 (27%) aneurysms and favorable occlusion in 14 (47%).

CONCLUSIONS

The use of large diameter DEDs was safe and feasible. The mid-term occlusion rates are acceptable considering the complex subset of aneurysms studied. Further studies are warranted to define the indications for large-diameter DEDs and to evaluate their long-term efficacy.

Cavernous Sinus Syndrome in a Polio-Afflicted Patient With Multiple Aneurysms

Cavernous sinus syndrome (CSS) is a complex, multifactorial condition that presents with a myriad of signs and symptoms including ptosis, double vision, and headache. We present the case of a 65-year-old woman with a chief concern of left-eye pain, including polio syndrome and hip replacement surgery. Unlike typical CSS cases often linked to tumors, this patient's condition involved a carotid-cavernous fistula (CCF), multiple internal carotid artery aneurysms, and a pericallosal aneurysm, without any associated tumor. She presented with severe left eye pain, ptosis, double vision, vomiting, headache, and other neurological symptoms since she woke up. Her treatment at a tertiary care center included diagnostic imaging, a cerebral angiogram, and embolization procedures, and she was discharged in stable condition. This case adds significant value to the medical literature by documenting the successful management of CSS with multiple aneurysms and a CCF, highlighting the importance of personalized treatment strategies and the effectiveness of modern embolization techniques in complex neurological conditions.

Optimal duration of dual antiplatelet therapy for stent-assisted coiling or flow diverter placement

BACKGROUND

Dual antiplatelet therapy (DAPT) is necessary to prevent thromboembolic complications after stent-assisted coiling (SAC) or flow-diversion (FD) for cerebral aneurysms, but the optimal antiplatelet regimen remains unclear.

OBJECTIVE

To determine the optimal DAPT duration in patients with SAC/FD.

METHODS

This multicenter cohort study enrolled patients who received SAC/FD for cerebral aneurysms at seven Japanese institutions between January 2010 and December 2020. The primary outcome was the time from procedure to the occurrence of a composite of target vessel-related thromboembolic events, procedure-unrelated major bleeding events, or death. The cumulative event-free survival rates were analyzed using a Kaplan-Meier curve, and the differences in each outcome between the groups dichotomized by the duration of DAPT were analyzed using the log-rank test.

RESULTS

Of 632 patients (median observational period, 646 days), primary outcome occurred in 63 patients (10.0%), most frequently within 30 days after the procedure. The cumulative event-free survival rates at 30 days, 1 year, and 2 years after the procedure were 93.3% (91.4 to 95.3%), 91.5% (89.3 to 93.7%), and 89.5% (87.0 to 92.0%), respectively. The cumulative event-free survival rates after switching to monotherapy were similar for the >91 and <90 days DAPT groups in the population limited to patients who were switched from DAPT to monotherapy without major clinical events.

CONCLUSIONS

Thromboembolic events rarely occurred beyond 30 days after SAC/FD. The duration of DAPT may be shortened if patients have a periprocedural period without events. Further prospective studies are warranted to determine the optimal duration of antiplatelet therapy.

TRIAL REGISTRATION NUMBER

UMIN000044122 :https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000050384.

Safety and Efficacy of Low-Profile Braided Stents versus Flow Diverters in the Reconstructive Technique in the Treatment of Patients with Vertebrobasilar Dolichoectasia Aneurysms: A Cohort of 47 Patients with Long-Term Follow-Up

BACKGROUND AND PURPOSE

Vertebrobasilar dolichoectasia aneurysm is a rare type of cerebrovascular disorder with a poor natural history, and endovascular treatment is widely accepted. Whether a high-profile braided stent (flow diverter) could promote occlusion of vertebrobasilar dolichoectasia aneurysm without increasing the complications rather than a low-profile braided stent remains uncertain. The aim of the study was to present a single-center experience of the safety and efficacy of a low-profile braided stent versus a flow diverter in treating patients with vertebrobasilar dolichoectasia aneurysms.

MATERIALS AND METHODS

The retrospective review was conducted on a total of 432 consecutive patients diagnosed with posterior circulation aneurysms who underwent endovascular treatment in our center from August 2013 to December 2021. Among these patients, 47 individuals with vertebrobasilar dolichoectasia aneurysms who were treated with low-profile braided stents or flow diverters were included. Vertebrobasilar dolichoectasia aneurysms involving only the vertebral artery were excluded. Patients were divided into 2 groups: the low-profile braided stent group and the flow diverter group based on the device used. Safety and efficacy outcomes were subsequently analyzed.

RESULTS

There were 25 total patients enrolled in low-profile braided stent group and 22 patients in flow diverter group. The safety of low-profile braided stents and flow diverters in the treatment of vertebrobasilar dolichoectasia aneurysms was evaluated by clinical outcome, a new neurologic deficit due to procedural complications, and neurologic death. The rates of good clinical outcome were similar between the 2 groups (low-profile braided stent, 56%, versus flow diverter, 59.1%; P = .831), and the rates of neurologic death were also similar (low-profile braided stent, 12%, versus flow diverter, 9.1%; P = .747). Higher rates of new neurologic deficits due to procedural complications were observed in the flow diverter group, but the difference was not significant (low-profile braided stent, 24%, versus flow diverter, 40.9%; P = .215). The efficacy was evaluated by angiographic occlusion of vertebrobasilar dolichoectasia aneurysms and progression of mass effect resulting from these aneurysms. Significantly higher rates of complete occlusion of vertebrobasilar dolichoectasia aneurysms were shown in the flow diverter group (41.2%; P = .028) than in the low-profile braided stent group (10%).

CONCLUSIONS

Both low-profile braided stents and flow diverters have similar high risks in reconstructive techniques in the treatment of vertebrobasilar dolichoectasia aneurysms, while a flow diverter is more effective in promoting complete occlusion of vertebrobasilar dolichoectasia aneurysm than a low-profile braided stent. A flow diverter may be a better alternative for carefully selected patients with vertebrobasilar dolichoectasia aneurysms.

A Novel Braided Stent With Customized Simulation Software for Treatment of Intracranial Aneurysms: Multicenter Prospective Trial Before Unrestricted Clinical Application

BACKGROUND AND OBJECTIVES

Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the "premarket" clinical trial of a new braided stent with a customized simulation software.

METHODS

A stent system with 3 mesh density types (16, 24, and 32 wire mesh) was designed based on computational flow dynamics technology, and a simulation software (virtual stent planner [VSP]) was developed for the optimal stent deployment planning. Stents were selected after simulation on preoperative 3D-processed angioimages, and accuracy of the VSP was evaluated.

RESULTS

Thirty-three unruptured intracranial aneurysms were successfully treated with VSP guidance. Twenty aneurysms (61%) were anterior circulation aneurysms, and 13 (39%) were posterior circulation aneurysms. The average aneurysm size was 7.1 mm, and the mean follow-up period was 19.2 months (11-39.0). There was no major recurrence or retreatment during follow-up, 2 morbidity cases, and no mortality. VSP planning presented slightly smaller stent dimensions compared with postdeployment: 24.2 vs 25.5 mm average, error -1.3 mm, and difference rate-5.46%.

CONCLUSION

Based on this result, the new stents and software guidance system were approved by the Ministry of Health and Welfare as a combined medical device. VSP provided precise deployment with minimal error compared with actual stent and can contribute to better stent deployment even for less experienced physicians.

Braid stability after flow diverter treatment of intracranial aneurysms: a systematic review and meta-analysis

BACKGROUND

The aim of this study was to evaluate the overall rates of braid changes associated with flow diverter (FD) treatment for intracranial aneurysms (IAs). Additionally, we sought to provide an overview of the currently reported definitions related to these complications.

METHODS

A systematic search was conducted from the inception of relevant literature up to April 2023, encompassing six databases. The included studies focused on patients with IAs treated with FDs. We considered four main outcome measures as FD braid changes: (1) fish-mouthing, (2) device braid narrowing, (3) device braid collapsing, and (4) device braid deformation. The data from these studies were pooled using a random-effects model.

RESULTS

A total of 48 studies involving 3572 patients were included in the analysis. Among them, 14 studies (39%) provided definitions for fish-mouthing. However, none of the included studies offered specific definitions for device braid narrowing, collapsing, or deformation, despite reporting rates for these complications in six, five, and three studies, respectively. The pooled rates for braid changes were as follows: 3% (95% CI 2% to 4%, I2=27%) for fish-mouthing, 7% (95% CI 2% to 20%, I2=85%) for narrowing, 1% (95% CI 0% to 3%, I2=0%) for collapsing, and 1% (95% CI 1% to 4%, I2=0%) for deformation.

CONCLUSION

The findings of this study suggest that FD treatment for IAs generally exhibits low rates of fish-mouthing, device braid narrowing, collapsing, and deformation. However, the lack of standardized definitions hinders the ability to compare device outcomes objectively, emphasizing the need for uniform definitions for FD braid changes in future prospective studies on FD.

Flow Diversion for the Treatment of Intracranial Aneurysms in a Peruvian Cohort: Experiences from a Limited-Resource Setting and Barriers to Implementation

BACKGROUND

Stenting with flow diverter devices (FDDs) has increasingly emerged as a treatment for intracranial aneurysms. The use of FDDs in the developing world has not been described.

METHODS

A retrospective review was performed of a cohort of patients who underwent flow diversion at 4 tertiary-care centers in Lima, Peru between January 2017 and June 2021. Demographics, clinical features, and aneurysm morphology were evaluated. Clinical outcomes were observed 3 months after discharge and occlusion rates were assessed 12 months after treatment.

RESULTS

Sixty-nine patients (mean age, 46 ±14.5 years; 17% female) were treated with FDDs; 4% (n = 3) of the treated aneurysms were ruptured. Most aneurysms were saccular (n = 65; 94%), <10 mm in maximum size (n = 60; 87%), and located in the anterior circulation (n = 67; 97%). Minor complications, such as groin hematoma, occurred in 7 cases. No serious complications or deaths occurred. Patients' functional status was excellent (modified Rankin Scale score 0-1) in 99% (n = 66) at discharge and 100% (n = 67) at 3 months. Although some patients were lost to follow-up, complete occlusion was seen in 76% (n = 31) of 41 treated patients at 12 months.

CONCLUSIONS

We report the largest multicenter experience of FDDs for cerebral aneurysm treatment in Peru, with reasonable outcomes that are comparable to other settings despite various challenges, suboptimal circumstances, and lack of resources.

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.

Parent artery occlusion after pipeline embolization device implantation of intracranial saccular and fusiform aneurysms

BACKGROUND

Studies reporting parent artery occlusion (PAO) after pipeline embolization device (PED) implantation are limited. The aim of this study was to investigate the incidence rate and risk factors of PAO after PED implantation.

METHODS

In this retrospective study, we enrolled consecutive patients with intracranial saccular and fusiform aneurysms treated with PED implantation at our institution. Multivariate logistic regression analysis was subsequently performed to determine the risk factors for PAO.

RESULTS

A total of 588 saccular and fusiform aneurysms were finally enrolled in the study. PAO was found in 14 (2.38%) aneurysms. The aneurysm complete occlusion rate was 79.6%. Compared with the non-PAO group, aneurysms in the PAO group were larger in size (20.08 vs 9.61 mm; p<0.001), had a greater neck diameter (9.92 vs 6.15 mm; p=0.001), and had higher frequencies of adjunctive coils (64.3% vs 35.7%; p=0.028). In the multivariate logistic analysis, aneurysm size (OR 1.12, 95% CI 1.02 to 1.24; p=0.016) and the presence of poor wall apposition after balloon angioplasty (OR 7.74, 95% CI 1.28 to 46.82; p=0.026) were associated with PAO occurrence after adjusting for confounding factors.

CONCLUSIONS

In this study, the incidence rate of PAO following PED implantation was 2.38% in intracranial saccular and fusiform aneurysms. Aneurysm size and residual presence of poor wall apposition after balloon angioplasty were risk factors for PAO. Further research is required to better understand the mechanisms of PAO.

Verification of software-based preoperative simulation of flow diverters in clinical cases

OBJECTIVE

The authors sought to verify the use of a preoperative simulation software for the treatment of intracranial aneurysms using flow diverters (FDs) based on three-dimensional rotational angiography (3DRA) data.

METHODS

Based on 3DRA data, the preoperative simulation software (UKNOW) was used to simulate the deployment of virtual FDs. The length and dimensions of virtual and real devices were compared. The deployment plan recommended by the UKNOW software was preliminarily used to complete implantations in the real world. During the experiment, experienced neurointerventional experts were responsible for supervising and judging information such as the length, dimension, and deployment location of the FDs.

RESULTS

This study retrospectively analyzed the data of 29 patients who received FD treatment. There was no statistical difference between the length of the real device and the virtual device (p = 0.6). The dimensions of FDs recommended by the software were consistent with the dimensions used in 24 out of the 29 real cases. In four of the remaining five cases, neurointerventional experts found that the FD dimensions recommended by the software were superior to those were actually used. Thus, the accuracy rate for FD dimension recommendations by the UKNOW software was 96.6% (28/29). Procedures performed in five cases using deployment plans recommended by the UKNOW software all achieved good postoperative results; the deployment positions of the device were reasonable, and all devices showed good wall adherence.

CONCLUSIONS

UKNOW software could accurately simulate the length and deployment position of the real FDs and provide suitable device dimensions.

Long-term outcomes of flow diversion for unruptured intracranial aneurysms: a systematic review and meta-analysis

BACKGROUND

Flow diverters have been widely used in clinical practice for more than a decade. However, most outcome data are limited to 1 year timepoints. This study aims to offer meta-analysis data on long-term (>1 year) safety and effectiveness results for patients with aneurysms treated with flow diverters.

METHODS

PubMed, Web of Science, Embase, and SCOPUS were searched up to February 24, 2022 using the AutoLit platform. We included primary studies assessing the long-term outcomes for flow diverter devices to manage unruptured internal carotid artery aneurysms with a follow-up period of >1 year. The meta-analysis was carried out using Comprehensive Meta-Analysis software (CMA).

RESULTS

Eleven studies were included in the meta-analysis. The pooled occlusion rates after flow diversion treatment for unruptured intracranial brain aneurysms were 77%, 87.4%, 84.5%, 89.4%, 96% for 1 year, 1-2 years, 2 years, 3 years, and 5 years follow-up, respectively. The in-stent stenosis rate was 4.8% and the retreatment rate for the long-term follow-up period was 5%. No delayed rupture of the aneurysm was reported, and there was one case of delayed ischemic stroke. The sensitivity analysis of the prospective studies showed a complete occlusion rate of 83.5% and 85.2% for 1 and 3 years of follow-up, respectively.

CONCLUSION

Flow diverters are safe and effective in short- and long-term follow-up and rarely cause serious delayed side effects.

Derivo embolization device for intracranial aneurysms: a Spanish multicenter retrospective study

BACKGROUND

Flow diverters have emerged in recent years as a safe and effective treatment for intracranial aneurysms, with expanding indications. The Derivo embolization device (DED) is a second-generation flow diverter with a surface finish that may reduce thrombogenicity. We report our multicenter experience evaluating its safety and efficacy.

METHODS

We retrospectively analyzed all patients treated with the DED in eight centers in Spain between 2016 and 2020. Demographics, clinical data, procedural complications, morbidity and aneurysm occlusion rates were collected.

RESULTS

A total of 209 patients with 250 aneurysms were treated (77.5% women). The majority of aneurysms were located in the internal carotid artery (86.8%) and most (69.2%) were small (<10 mm) with a median maximum diameter of 5.85 mm and median neck size of 4 mm. DED deployment was successful in all cases, despite two malfunctioning devices (1%). Major complications occurred in nine patients (4.3%), while mild neurologic clinical events were registered in 23 (11%); four patients died (1.9%). A total of 194 aneurysms had an angiographic follow-up at 6 months and showed complete aneurysm occlusion in 75% of cases. Twelve-month follow-up was available for 112 of the treated aneurysms, with a total occlusion rate of 83%.

CONCLUSION

The DED is a second-generation surface-modified flow diverter that presents an option for treatment of intracranial aneurysms with comparable safety and efficacy to other available flow diverter devices. Nonetheless, risks are not negligible, and must be balanced against the natural history risk of cerebral aneurysms, considering the tendency to widen indications for treatment of smaller and less complex lesions in day-to-day use.

Analysis of reported adverse events of pipeline stents for intracranial aneurysms using the FDA MAUDE database

OBJECTIVE

Flow diverting stents (FDS) are a validated device in the treatment of intracranial aneurysms, allowing for minimally invasive intervention. However, after its approval for use in the United States in 2011, post-market surveillance of adverse events is limited. This study aims to address this critical knowledge gap by analyzing the FDA Manufacturer and User Facility Device Experience (MAUDE) database for patient and device related (PR and DR) reports of adverse events and malfunctions.

METHODS

Using post-market surveillance data from the MAUDE database, PR and DR reports from January 2012-December 2021 were extracted, compiled, and analyzed with R-Studio version 2021.09.2. PR and DR reports with insufficient information were excluded. Raw information was organized, and further author generated classifications were created for both PR and DR reports.

RESULTS

A total of 2203 PR and 4017 DR events were recorded. The most frequently reported PR adverse event categories were cerebrovascular (60%), death (11%), and neurological (8%). The most frequent PR adverse event reports were death (11%), thrombosis/thrombus (9%) cerebral infarction (8%), decreased therapeutic response (7%), stroke/cerebrovascular accident (6%), intracranial hemorrhage (5%), aneurysm (4%), occlusion (4%), headache (4%), neurological deficit/dysfunction (3%). The most frequent DR reports were activation/positioning/separation problems (52%), break (9%), device operates differently than expected (4%), difficult to open or close (4%), material deformation (3%), migration or expulsion of device (3%), detachment of device or device component (2%).

CONCLUSIONS

Post-market surveillance is important to guide patient counselling and identify adverse events and device problems that were not identified in initial trials. We present frequent reports of several types of cerebrovascular and neurological adverse events as well as the most common device shortcomings that should be explored by manufacturers and future studies. Although inherent limitations to the MAUDE database are present, our results highlight important PR and DR complications that can help optimize patient counseling and device development.

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.

Flow diversion for the treatment of intracranial bifurcation aneurysms: a systematic review and meta-analysis

BACKGROUND

Flow diversion (FD: flow diversion, flow diverter) is an endovascular treatment for many intracranial aneurysm types; however, limited reports have explored the use of FDs in bifurcation aneurysm management. We analyzed the safety and efficacy of FD for the management of intracranial bifurcation aneurysms.

METHODS

A systematic review identified original research articles that used FD for treating intracranial bifurcation aneurysms. Articles with >4 patients that reported outcomes on the use of FDs for the management of bifurcation aneurysms along the anterior communicating artery (AComA), internal carotid artery terminus (ICAt), basilar apex (BA), or middle cerebral artery bifurcation (MCAb) were included. Meta-analysis was performed using a random effects model.

RESULTS

19 studies were included with 522 patients harboring 534 bifurcation aneurysms (mean size 9 mm, 78% unruptured). Complete aneurysmal occlusion rate was 68% (95% CI 58.7% to 76.1%, I2=67%) at mean angiographic follow-up of 16 months. Subgroup analysis of FD as a standalone treatment estimated a complete occlusion rate of 69% (95% CI 50% to 83%, I2=38%). The total complication rate was 22% (95% CI 16.7% to 28.6%, I2=51%), largely due to an ischemic complication rate of 16% (95% CI 10.8% to 21.9%, I2=55%). The etiologies of ischemic complications were largely due to jailed artery hypoperfusion (47%) and in-stent thrombosis (38%). 7% of patients suffered permanent symptomatic complications (95% CI 4.5% to 9.8%, I2=6%).

CONCLUSION

FD treatment of bifurcation aneurysms has a modest efficacy and relatively unfavorable safety profile. Proceduralists may consider reserving FD as a treatment option if no other surgical or endovascular therapy is deemed feasible.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Surpass embolization of intracranial aneurysms: Perspective from a 2-year longitudinal follow-up study across high volume comprehensive stroke centers

BACKGROUND

Surpass Streamline (SS; Stryker^©) is an over-the-wire first-generation flow diverter (FD). There is a scarcity of data on real-world outcomes and complications of this FD.

METHODS

A retrospective review of consecutive cases between January 2019 and July 2021 at two high-volume comprehensive stroke centers, involving SS was conducted.

RESULTS

Fifty-five patients harbored 69 treated aneurysms, of which 96% were in the internal carotid petrous to terminus segments and 88% were <10 mm in size, and 12% measuring 10-24 mm. Raymond Roy Grade 1 occlusion was noted in 55 aneurysms (79.7%) at 1 year. Median follow-up duration was 26 months (mean = 26.06). Major complications were seen in eight patients (14.5%; 95% CI 6.5-26.7) and mortality attributable to SS stenting complications occurred in two (4.3%) patients. Four (7.2%) had ophthalmologic thromboembolic complications and two had (3.6%) ischemic complications. Procedural complications occurred in 10 patients (18.18%; 95% CI 9.1-30.9). Technical complications during procedure (n = 3, 5.3%) were: "confirmed" distal middle cerebral artery (MCA) guidewire perforation; "suspected" distal MCA guidewire perforation causing post-procedural subarachnoid hemorrhage and internal carotid artery dissection causing ischemic stroke. Seizures were seen in 5 (9.09%) and carotid-cavernous fistula in 1 (1.8%). Multivariate regression analysis showed technical challenges significantly predicted occurrence of major complications (p = 0.001; R²= 0.39, F(13,43) = 2.15, p = 0.029). Univariate analysis showed technical challenges significantly predicted ophthalmological complications (R²= 0.06, F(1,55) = 4.04, p = 0.049) and major complications (R²= 0.21, F(1,55) = 15.11, p = 0.0002).

CONCLUSION

Large-scale future registry should focus on national data regarding SS safety, technical challenges, and procedural complications. We present one of the longest follow-ups for SS in literature.

A review and journey in intrasaccular treatment of intracranial aneurysms

The invested effort and collaboration of clinicians and medical device companies to improve occlusion rates and clinical outcomes for patients with intracranial aneurysms treated via less invasive endovascular means led to the development of the concept of intrasaccular devices. Intrasaccular devices were introduced to offer simple treatment options, offering easier navigation through difficult anatomy, simpler and quicker deployment into large and wide-neck aneurysms. Additionally, they offer easier sizing, whilst offering a wide range of options suitable for aneurysms of different sizes. The concept of most intrasaccular devices is to occupy the aneurysm neck, however offering better stability than simple coiling, therefore increasing the chance of long-term aneurysm occlusion. This is achieved without a sizable metal content within the parent vessel, contrary to flow diverters, theoretically reducing the risk of thromboembolic events. This review aims to discuss the history and latest developments of intrasaccular intracranial devices, which offer an exciting and potentially successful option for treatment of complex intracranial aneurysms.

Long-term outcomes following pipeline embolization of unruptured aneurysms

BACKGROUND

Flow diversion using the pipeline embolization device (PED) for unruptured aneurysms is associated with high occlusion and low morbidity and mortality. However, most reports have limited follow-up of 1-2 years. Therefore, we sought to report our outcomes after PED for unruptured aneurysms in patients with at least 5-years of follow-up.

METHODS

Review of patients undergoing PED for unruptured aneurysms from 2009 to 2016.

RESULTS

Overall, 135 patients with 138 aneurysms were included for analysis. Seventy-eight percent of aneurysms (n=107) over a median radiographic follow-up of 5.0 years underwent complete occlusion. Among aneurysms with at least 5-years of radiographic follow-up (n=71), 79% (n=56) achieved complete obliteration. No aneurysm recanalized after radiographic obliteration. Furthermore, over a median clinical follow-up period of 4.9 years, 84% of patients (n=115) self-reported mRS scores between 0 and 2. For patients with at least 5-years of clinical follow-up, 88% (n=61) reported mRS between 0 and 2. In total, 3% (n=4) of patients experienced a major, non-fatal neurologic complication related to the PED, 5% (n=7) of patients experienced a minor neurologic complication related to PED placement, and 2% (n=3) died from either delayed aneurysm rupture, delayed ipsilateral hemorrhage after PED placement, or delayed (9 months after treatment) neural compression after progressive thrombosis of a PED-treated dolichoectactic vertebrobasilar aneurysm.

CONCLUSIONS

Treatment of unruptured aneurysms with the PED is associated with high rates of long-term angiographic occlusion and low, albeit clinically important, rates of major neurologic morbidity and mortality. Thus, flow diversion via PED placement is safe, effective, and durable.

Assessment of the flow-diverter efficacy for intracranial aneurysm treatment considering pre- and post-interventional hemodynamics

Endovascular treatment of intracranial aneurysms with flow diverters (FD) has become one of the most promising interventions. Due to its woven high-density structure they are particularly applicable for challenging lesions. Although several studies have already conducted realistic hemodynamic quantification of the FD efficacy, a comparison with morphologic post-interventional data is still missing. This study analyses the hemodynamics of ten intracranial aneurysm patients treated with a novel FD device. Based on pre- and post-interventional 3D digital subtraction angiography image data, patient-specific 3D models of both treatment states are generated applying open source threshold-based segmentation methods. Using a fast virtual stenting approach, the real stent positions available in the post-interventional data are virtually replicated and both treatment scenarios were characterized using image-based blood flow simulations. The results show FD-induced flow reductions at the ostium by a decrease in mean neck flow rate (51%), inflow concentration index (56%) and mean inflow velocity (53%). Intraluminal reductions in flow activity for time-averaged wall shear stress (47%) and kinetic energy (71%) are present as well. However, an intra-aneurysmal increase in flow pulsatility (16%) for the post-interventional cases can be observed. Patient-specific FD simulations demonstrate the desired flow redirection and activity reduction inside the aneurysm beneficial for thrombosis formation. Differences in the magnitude of hemodynamic reduction exist over the cardiac cycle which may be addressed in a clinical setting by anti-hypertensive treatment in selected cases.

Single flow diverter to manage multiple intracranial aneurysms in a parent artery

BACKGROUND

Endovascular coil embolization has become an important method in the management of intracranial aneurysm. However, simultaneously coiling multiple intracranial aneurysms (MIAs) in unilateral parent artery in one-stage may fail or insufficient in geographic difficult aneurysm. Flow diverter (FD) has the potential to manage MIAs with nonamenable to coiling. Herein, we report periprocedural morphologic change and outcomes using single FD to manage unruptured MIAs in a parent artery.

METHODS

Over a 3-year period, a total of 63 patients with 126 MIAs successful managed by single FD with complete angiographic follow-up. There were 49 women and 14 men, with ages ranging from 42 to 77 years (mean: 59 years). We retrospectively assessed the clinical data, aneurysm characteristic, angiographic and clinical outcomes of all patients and compared with 171 patients with single aneurysm managed by FD.

RESULTS

Sixty-one patients with 118 aneurysms (94%) located in internal carotid artery or middle cerebral artery (n = 4, 3%), two patients with four aneurysms (4%) were found in the basilar artery. The mean aneurysm size was 5.6 mm (range from 1.8 to 38 mm). Mean angiographic follow-up was 14 months. Complete obliteration of aneurysm was achieved in 102 aneurysms (83%), subtotal or partial aneurysm obliteration was demonstrated in 18 aneurysms (15%), unchanged aneurysm morphology in three (2%). Aneurysm morphology synchronized alteration in 55 patients (87%), other eight patients (13%) with 16 aneurysms showed different morphologic alteration in angiographic follow-up. Four patients (6.3%) had intraprocedural ischemic complication. During the follow-up period, 61 patients (97%) were neurologic stable; there was no hemorrhagic or ischemic event.

CONCLUSION

Single FD was feasible to treat MIAs in a parent artery with both effective and safe in one-stage management. Most aneurysms synchronized alteration of morphology in a mid-term follow-up. The procedure was almost the same with FD managing single aneurysm, but longer FD is needed in MIAs.

Microsurgical Treatment of Previously Coiled Giant Aneurysms: Experience with 6 Cases and Literature Review

OBJECTIVE

Surgical treatment of insufficiently embolized (coiled) or recurrent giant aneurysms has not been well established in the literature. The aim of this study is to bring up the surgical difficulties of these rare aneurysms and to offer solutions.

METHODS

A database was queried for giant aneurysms that had been previously embolized and subsequently required surgical treatment. We only found 29 aneurysms in the literature and here, we report 6 more surgical cases with patient characteristics, radiological studies, applied surgical techniques, and outcomes which were reviewed retrospectively.

RESULTS

Four females and 2 males, with a mean age of 45.6 years took part in the study. The most common aneurysm location was the middle cerebral artery. While 5 aneurysms were successfully clipped, 1 was excised and the neck was closed with micro sutures. The coils were compulsorily removed in 3 patients. Postoperative digital subtraction angiography confirmed total occlusion of the aneurysms in all cases. Overall morbidity was 16.6%. There was no mortality. No recurrence was observed in the angiographic follow-up (mean 22.6 months, range 7-47 months). The literature review also determined that 97.1% of 35 previously coiled giant aneurysms (including ours) were occluded using various surgical techniques, with 82.8% good outcome.

CONCLUSIONS

Surgical clipping is a safe and effective procedure for the treatment of insufficiently embolized or recurrent giant aneurysms after coiling. If possible, the coils should not be removed. However, if safe clipping is not possible due to the coils, the removal of the coils should not be avoided.

Endovascular treatment of unruptured intracranial aneurysms with flow diverters: A retrospective long-term single center analysis

PURPOSE

The introduction of flow diverters (FDs) in 2007 greatly enhanced the treatment of intracranial aneurysms. Here, we present our long-term clinical experience in treating unruptured intracranial aneurysms with FDs.

METHODS

107 patients with unruptured aneurysms and treated with an FD between 2010 and 2019 were retrospectively reviewed. Aneurysm occlusion, procedural complications, and clinical outcome were evaluated.

RESULTS

Angiographic follow-up was available for 93 patients with a mean long-term follow-up time of 28.4 ± 21.6 months. Additional coiling was performed in 15.1% of patients (n = 14). Adequate aneurysm occlusion (Kamran grades 3 and 4) at long-term follow-up was achieved in 94.6% of patients (n = 88). 3.2% (n = 3) required endovascular retreatment since the last follow-up showed a lack of aneurysm occlusion (Kamran grade 0) due to a foreshortening of the FD. Incomplete opening of the FD and parent vessel occlusion was seen in 1.1% (n = 1) and 3.2% (n = 3) of patients, respectively. In-stent stenosis was observed in 57% (n = 53) of cases at short-term follow-up and 22.6% (n = 21) at long-term, which were moderate and asymptomatic overall. In-stent stenosis decreased significantly between short- and long-term follow-ups (31.4 ± 17.0% vs 9.7 ± 13.6%, respectively; p ≤ 0.001). Thromboembolic and hemorrhagic events occurred in 7.5% (n = 7) and 1.1% (n = 1) of patients, respectively. Good clinical outcome (modified Rankin scale: 0-2) was obtained in 97.8% (n = 91) leading to an overall treatment-related morbidity of 2.2% (n = 2). There was no procedural mortality.

CONCLUSION

Our study shows that FD treatment of unruptured intracranial aneurysms is effective and safe with high occlusion rates and low rates of permanent morbidity at long-term follow-up.

Factors associated with in-stent stenosis after cerebral aneurysm embolization using a Pipeline embolization device

BACKGROUND

Flow-diverting (FD) stents, with or without coiling, are a mainstay in endovascular treatment of intracranial aneurysms (IAs). One observed complication from flow diverter stent (FDS) insertion has been in-stent stenosis. Though previously studied in the short-term period, the long-term history of this complication has yet to be described.

METHODS

We performed a retrospective cohort study of consecutive IAs treated with Pipeline Embolization Device (PED), with or without coiling, at our centre between September 2014 and December 2018 that had at least one digital subtraction angiogram (DSA) during follow-up. In-stent stenosis was measured from DSA images, and associated patient and procedural characteristics were analysed.

RESULTS

94 patients treated with PED for IA were identified. On initial DSA during follow-up, 52 patients (55.3%) had in-stent stenosis within the PED. Of these 52 patients, 17 had a second DSA during follow-up. In this 2nd DSA, improvement and/or stable in-stent stenosis was seen 16 patients (94.1%). One patient in this group had worsening in-stent stenosis had a vertebrobasilar junction FD stent. Of the patients without in-stent stenosis on initial DSA, 15 had a second DSA during follow-up. Only one of these patients (6.7%) had new appearance of in-stent stenosis (measuring 5%). Multivariate analysis found statin use to be predictive of in-stent stenosis (p = 0.020, Odds ratio = 0.279 and 95% confidence interval = 0.095-0.821).

CONCLUSIONS

In-stent stenosis after FDS placement was seen in 53.2% of cases, which had between 1-50% of stenosis. 82.4% had resolution/improvement of their stenosis. Statin use was protective of in-stent stenosis.

Coiling followed by staged flow diversion for large and giant intracranial aneurysms

Objective

Delayed aneurysm rupture is a fatal complication after flow diversion treatment for large and giant intracranial aneurysms. This study aimed to investigate the feasibility and safety of coiling first and followed by planned flow diversion to prevent delayed aneurysm rupture.

Methods

From January 2017 to December 2021 in two institutions, patients with unruptured intracranial aneurysms treated by coiling first and planned flow diversion were retrospectively collected. Data on demographic and aneurysmal characteristics, procedural details, and clinical and angiographic outcomes were reviewed.

Results

Thirty patients were included (7 Males and 23 Females; Median age 57 years). Aneurysmal size ranged from 11.8 to 26.8 mm, with a median value of 18.5 mm. All aneurysms were located within the intradural segment of internal carotid arteries. Coiling and planned flow diversion were successfully performed in all patients. The time interval between coiling and flow diversion was 3.9–6.7 weeks, with a median value of 5.2 weeks. No hemorrhagic or ischemic complications occurred during the procedures and follow-up. Complete or subtotal occlusion was achieved in 86.7% (26/30) at the last angiographic follow-up (median 6.7 months).

Conclusion

The preliminary data suggested that coiling unruptured intracranial aneurysms followed by planned flow diversion is both safe and effective. Further studies with larger cohorts are needed to verify the effect of this new strategy in preventing delayed rupture after flow diversion.

Fluoroscopy, CT, and MR imaging characteristics of a novel primarily bioresorbable flow-diverting stent for aneurysms

BACKGROUND

Five to ten percent of the global population have unruptured intracranial aneurysms, and ruptured brain aneurysms cause approximately 500,000 deaths a year. Flow-diverting stent treatment is a less invasive intracranial aneurysm treatment that induces aneurysm thrombosis. The imaging characteristics of a novel primarily bioresorbable flow-diverting stent (BFDS) are assessed in comparison to the leading metal stent using fluoroscopy, CT, and MRI.

METHODS

X-ray/fluoroscopic images of stents were taken using a human cadaveric skull model. CT and MRI were acquired using silicone flow models of residual aneurysms. Images were analyzed with Likert scales in anonymous surveys by neurointerventionalists. Quantitative measurements of radiographic density (CT) and artifact boundary size (CT & MRI) were also obtained.

RESULTS

Visibility of the BFDS on X-ray was less than the metal stent but deemed adequate for deployment and intraprocedural assessment. The metal stent was more radiopaque than the BFDS on CT, but qualitative assessment was not significantly different for the two stents. MRI imaging was significantly better using the BFDS in terms of overall artifact and intraluminal assessment.

CONCLUSIONS

The BFDS has adequate visualization on X-ray/fluoroscopy and should be clinically acceptable for fluoroscopic deployment. On MRI, there is less quantitative artifact as well as overall improved qualitative assessment that will allow for more detailed non-invasive imaging follow-up of treated aneurysms, potentially reducing the need for digital subtraction catheter angiography.

Management of In-Stent Stenosis with Dual Antiplatelet Therapy Following Pipeline Embolization of Intracranial Aneurysms

OBJECTIVE

Flow diversion of intracranial aneurysms with the pipeline embolization device (PED) may produce angiographically apparent stenosis within the PED, which can lead to secondary ischemic complications. In-stent stenosis can be treated medically with dual antiplatelet therapy (DAPT), but the safety and efficacy of this approach are unknown. In this work, we review the safety and efficacy of DAPT to prevent progression of in-stent stenosis or development of cerebral ischemia.

METHODS

Clinical and angiographic data from eligible patients were assessed from a prospectively maintained neurointerventional database. Details surrounding in-stent stenosis and DAPT were extracted. Patients were included in this study if in-stent stenosis was detected at any angiographic follow-up and managed with DAPT. The primary efficacy endpoint was lack of angiographic progression of in-stent stenosis or new ipsilateral infarct following initiation of medical therapy.

RESULTS

In total, 23 PED constructs developed in-stent stenosis and were managed with DAPT. Follow-up angiography was available for 19 constructs. Eighty-nine percent (17/19) of PED constructs achieved the primary endpoint of lack of stenosis progression and lack of new ipsilateral ischemic events. Of the 2 PED constructs that failed to achieve the primary endpoint of this study, one demonstrated worsening of in-stent stenosis from 55% to 76% over 16 months, while the other developed ipsilateral ischemic stroke 4 months after detection of in-stent stenosis. In addition, one patient experienced intracranial hemorrhage 9 months after the initiation of DAPT.

CONCLUSIONS

Progression of in-stent stenosis and new ipsilateral ischemic events are limited in the presence of DAPT. However, hemorrhagic events related to DAPT may occasionally occur.

Predictors of flow diverter stent in large and giant unruptured intracranial aneurysms, single-center experience

Background

Flow diversion with or without coiling has been established as the treatment of choice for large unruptured aneurysms. This study aims to assess possible predictors for radiological and clinical outcome such as location of the aneurysm (anterior or posterior circulation), complexity by a branching artery, bifurcation, and adjuvant coiling.

Methods

This study was conducted on 65 consecutive patients with 65 large, unruptured intracranial aneurysms (size ≥ 10 mm) treated with flow diverters. Follow-up angiography was done for 60 patients (92.3%) at 12 ± 8.6 months range from 3 to 36 months.

Results

Complete occlusion was achieved in 50 from 60 aneurysms (83.4%), while 8 aneurysms (13.3%) had neck remnant, and another two aneurysms (3.3%) remained with aneurysmal remnant. Periprocedural complications were encountered in 14 patients (21.5%) with morbidity in six patients (9.2%) and mortality in one patient (1.5%). In a multivariate logistic regression, anterior versus posterior location was less likely associated with worse outcome; adjusted OR (95% CI) of 0.16 (0.07–0.01), p = 0.006. Complete occlusion in complex aneurysms with branching artery was 60% versus 88% in simple aneurysms without branching artery (p-value = 0.04).

Conclusions

Flow diverter deployment of a large, unruptured aneurysm in the anterior circulation might have a better outcome than one in the posterior circulation. Flow diverter of aneurysms with branching artery or at bifurcation might be associated with aneurysm persistence and complications respectively.

Adaptive wireless millirobotic locomotion into distal vasculature

Microcatheters have enabled diverse minimally invasive endovascular operations and notable health benefits compared with open surgeries. However, with tortuous routes far from the arterial puncture site, the distal vascular regions remain challenging for safe catheter access. Therefore, we propose a wireless stent-shaped magnetic soft robot to be deployed, actively navigated, used for medical functions, and retrieved in the example M4 segment of the middle cerebral artery. We investigate shape-adaptively controlled locomotion in phantoms emulating the physiological conditions here, where the lumen diameter shrinks from 1.5 mm to 1 mm, the radius of curvature of the tortuous lumen gets as small as 3 mm, the lumen bifurcation angle goes up to 120^°, and the pulsatile flow speed reaches up to 26 cm/s. The robot can also withstand the flow when the magnetic actuation is turned off. These locomotion capabilities are confirmed in porcine arteries ex vivo. Furthermore, variants of the robot could release the tissue plasminogen activator on-demand locally for thrombolysis and function as flow diverters, initiating promising therapies towards acute ischemic stroke, aneurysm, arteriovenous malformation, dural arteriovenous fistulas, and brain tumors. These functions should facilitate the robot’s usage in new distal endovascular operations.

Accessibility into the distal vascular systems to treat various diseases remains challenging using medical catheters. Here, Wang et al. demonstrate that a stent-shaped wireless magnetic soft robot enables adaptive locomotion and medical functions into these distal vascular regions.

Long-Term Durability and Recurrence Patterns After Endovascular Treatment for Basilar Tip Aneurysms

BACKGROUND

Treating recurrence after coil embolization of basilar tip aneurysm remains challenging even with the development of endovascular procedures. The present study evaluated long-term durability and recurrence patterns after endovascular treatment of basilar tip aneurysms.

METHODS

Data of 116 consecutive patients treated with endovascular therapy at 3 regional hospitals from 2002-2019 were retrospectively analyzed. Aneurysms were ruptured in 51 cases and unruptured in 65 cases, with a mean maximal diameter of 7.8 mm (>15 mm in 14 patients) and a mean follow-up period of 5.8 ± 4.3 years.

RESULTS

Recurrence was observed in 24 of the 116 patients (21%), and 14 patients were retreated. The 5-year recurrence-free survival rate was 75.3%. Cox proportional hazards analysis found that recurrence correlated significantly with maximal aneurysm diameter >10 mm (P = 0.001; hazard ratio: 3.95, 95% confidence interval: 1.76-8.90) and incomplete occlusion (P = 0.003; hazard ratio: 4.43, 95% confidence interval: 1.63-12.00). Recurrence pattern was classified into 3 types: neck type (9 patients), regrowth type (10 patients), and regrowth type of initially thrombosed aneurysms (3 patients). Rerupture occurred in neck type with de novo aneurysm formation adjacent to the neck (n = 3) and regrowth type with dome filling (n = 4).

CONCLUSIONS

Recurrence after coil embolization for basilar tip aneurysms is associated with large aneurysms and incomplete occlusion at initial embolization. Understanding the patterns of recurrence is useful for predicting recurrence and selecting treatment strategies.

Outcomes after Flow Diverter Treatment in Subarachnoid Hemorrhage: A Meta-Analysis and Development of a Clinical Prediction Model (OUTFLOW)

Background: patients with a subarachnoid hemorrhage (SAH) might need a flow diverter (FD) placement for complex acutely ruptured intracranial aneurysms (IAs). We conducted a meta-analysis and developed a prediction model to estimate the favorable clinical outcome after the FD treatment in acutely ruptured IAs. Methods: a systematic literature search was performed from 2010 to January 2021 in PubMed and Embase databases. Studies with more than five patients treated with FDs within fifteen days were included. In total, 1157 studies were identified. The primary outcome measure was the favorable clinical outcome (mRS 0–2). Secondary outcome measures were complete occlusion rates, aneurysm rebleeding, permanent neurologic deficit caused by procedure-related complications, and all-cause mortality. A prediction model was constructed using individual patient-level data. Results: 26 retrospective studies with 357 patients and 368 aneurysms were included. The pooled rates of the favorable clinical outcome, mortality, and complete aneurysm occlusion were 73.7% (95% CI 64.7–81.0), 17.1% (95% CI 13.3–21.8), and 85.6% (95% CI 80.4–89.6), respectively. Rebleeding occurred in 3% of aneurysms (11/368). The c-statistic of the final model was 0.83 (95% CI 0.76–0.89). All the studies provided a very low quality of evidence. Conclusions: FD treatment can be considered for complex ruptured IAs. Despite high complication rates, the pooled clinical outcomes seem favorable. The prediction model needs to be validated by larger prospective studies before clinical application.

Effect of flow diverter stent malposition on intracranial aneurysm hemodynamics—An experimental framework using stereoscopic particle image velocimetry

Background

Flow-diverting stents are increasingly used for the minimally-invasive treatment of intracranial aneurysms. However, a correct positioning of such devices can be challenging due to varying vessel diameters as well as the complex anatomy of the neurovasculature. As a consequence, unsuccessful treatment outcomes are increasingly reported requiring an improvement of the understanding of stent-induced flow modification.

Methods

To evaluate the effect of different degrees of flow diverter stent malposition on intra-aneurysmal hemodynamic changes, a controlled hemodynamic configuration was created using an idealized intracranial aneurysms model. Afterwards, four different treatment scenarios were reproduced comprising of 1) the ideal treatment, 2) an insufficient wall apposition in the region of the ostium, 3) a distorted device migrating into the aneurysm sac and 4) an inaccurately deployed stent due to wrong release location. For the assessment of the individual flow modifications, high-resolution stereoscopic particle image velocimetry (PIV) measurements were carried out.

Results

The analysis of the precise in-vitro PIV measurements reveals that in all cases a considerable reduction of the cycle-averaged and peak-systolic velocity was obtained. Compared to the untreated aneurysm configuration, the flow reduction ranged from 63% (scenario 4) up to 89% (scenario 3). The ideal treatment reached a reduction of 78%, which is known to be sufficient for a successful therapy. However, inaccurate device positioning leads to increased oscillating flow towards the lateral directions reducing the chances of sufficient thrombus formation.

Conclusions

High-resolution in-vitro PIV measurements enable an accurate quantification of the treatment efficacy for flow-diverting devices. Furthermore, insufficient treatment outcomes can be reproduces allowing for an assessment of intra-aneurysmal hemodynamic changes.

The Safety and Effectiveness of the Contour Neurovascular System (Contour) for the Treatment of Bifurcation Aneurysms: The CERUS Study

BACKGROUND

The Contour is a novel intra-aneurysmal flow disrupting device to treat intracranial aneurysms.

OBJECTIVE

To evaluate the safety and effectiveness of the Contour device for treatment of nonruptured intracranial bifurcation aneurysms through a prospective, multicenter, single-arm study.

METHODS

Thirty-four patients were enrolled. Primary end points were successful occlusion at 6 mo for efficacy and any major stroke or nonaccidental death up to 30 d or major disabling stroke within 6 mo for safety. Secondary end points were occlusion at 12 mo, retreatment rate, procedure time, and procedure-related/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee.

RESULTS

In total, 32 of 34 aneurysms were successfully implanted and, 2 of 34 in the intention-to-treat (ITT) group did not receive the Contour and were excluded from follow-up after 30 d. In addition, 2 of 32 were lost to angiographic follow-up and regarded as treatment failure. The primary safety end point was met in 2 patients in the ITT group. In the perprotocol (PP) group, complete occlusion was seen in 14 of 32 (44%) at 6 mo and 22 of 32 (69%) at 12 mo. Adequate occlusion (Raymond-Roy [RR] 1 and 2) was reached in 84% at a last available follow-up. One patient from the ITT group and 1 from the PP group received additional treatment during follow-up.

CONCLUSION

The Contour seems to be both safe and effective in the treatment of intracranial bifurcation aneurysms.

Flow-diverter stent to manage intracranial aneurysms: A single center experience

BACKGROUND

Endovascular coil embolization is an important method for managing intracranial aneurysms. However, aneurysm coiling may fail or be insufficient in geographically difficult aneurysms. A flow-diverter stent (FDS) is an alternative in these difficult coiling aneurysms. Thus, this study reports the experience and outcome of FDS management of intracranial aneurysms.

METHODS

Over 29 months, FDS treated 125 patients with 163 intracranial unruptured aneurysms. This study enrolled 31 men and 94 women, ranging from 17 to 81 years (mean, 58 years). Clinical data, aneurysm characteristics, and angiographic and clinical outcomes of patients treated by FDS were retrospectively assessed.

RESULTS

The current study found 151 (93%) aneurysms in the internal carotid artery. Most aneurysms (n = 118; 72%) were small (<7 mm). The mean aneurysm size was 6.2 mm (range, 2-38 mm). Follow-up angiography was available in 53 patients with 74 aneurysms (mean, 13 months). Successful FDS deployment in an ideal position was found in 125 of 130 patients (96%). Complete obliteration (CO) was achieved in 58 aneurysms (78%) in the mean 13-month angiographic follow-up. Smaller aneurysms (<7 mm) had a CO tendency than larger aneurysms (p < 0.01) in midterm follow-up. Seven patients (5.6%) had intraprocedural complications (in-stent thrombosis, three patients; distal embolic, two patients; iatrogenic carotid-cavernous fistula, and subarachnoid hemorrhage, one patient). Two patients (1.6%) suffered from permanent procedure-related morbidity (n = 1) or mortality (n = 1). No late hemorrhagic events or stent displacement occurred during the follow-up period.

CONCLUSION

Despite few procedural complications and some pieces of evidence of insufficient aneurismal treatment in a midterm angiographic follow-up, FDS was effective and safe in managing intracranial unruptured aneurysms, particularly in smaller aneurysms, which had better CO than larger ones.

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).

Pipeline Embolization Device for the Treatment of Ruptured Intracerebral Aneurysms: A Multicenter Retrospective Study

Background and Purpose: The utilization of flow diversion for ruptured intracerebral aneurysms (IAs) is still limited. We aimed to demonstrate our multicenter experience using the pipeline embolization device (PED) for ruptured IAs that were difficult to treat by clipping and coiling.

Methods: Thirty-eight patients with ruptured IAs who underwent PED treatment from 2015 to 2020 were retrospectively reviewed. Factors associated with procedure-related stroke (ischemic and hemorrhagic) and clinical and angiography outcomes were analyzed.

Results: There were 14 (36.8%) saccular IAs, 12 (31.6%) blister-like IAs, and 12 (31.6%) dissecting IAs. Perforator involvement was noted in 10 (26.3%) IAs. Early PED placement ( ≤ 15 days) and adjunctive coiling treatment were performed in 27 (71.1%) and 22 (57.9%) cases, respectively. The overall rate of stroke-related complications was 31.6% (12/38) (including rates of 10.5% for procedure-related hemorrhagic complications and 15.8% for procedure-related infarction). The mortality rate was 13.2% (5/38), and 84.2% of patients (32/38) had favorable outcomes. Thirty-two (84.2%) patients underwent follow-up angiographic evaluations; of these, 84.4% (27 patients) had complete occlusion and 15.6% had incomplete obliteration. Multivariate analysis revealed that early PED placement was not associated with a high risk of procedure-related stroke or an unfavorable outcome. Adjunctive coiling exhibited an association with procedure-related stroke (p = 0.073). Procedure-related hemorrhagic complications were significantly associated with an unfavorable outcome (p = 0.003). Immediate contrast stasis in the venous phase was associated with complete occlusion during follow-up (p = 0.050).

Conclusion: The PED is a feasible and effective treatment to prevent rebleeding and achieve aneurysm occlusion, but it is associated with a substantial risk of periprocedural hemorrhage and ischemic complications in acute ruptured IAs. Therefore, the PED should be used selectively for acutely ruptured IAs. Additionally, adjunctive coiling might increase procedure-related stroke; however, it may reduce aneurysm rebleeding in acutely ruptured IAs. Patients with immediate contrast stasis in the venous phase were more likely to achieve total occlusion. A prospective study with a larger sample size should be performed to verify our results.

The Woven EndoBridge for unruptured intracranial aneurysms: Results in 95 aneurysms from a single center

BACKGROUND AND PURPOSE

The Woven EndoBridge (WEB) is an intrasaccular flowdisruptor that is increasingly used for the treatment of (wide-necked) aneurysms. We present our experience with the WEB for unruptured aneurysms.

MATERIALS AND METHODS

Between April 2014 and August 2019, 93 patients with 95 unruptured aneurysms were primarily treated with the WEB. There were 69 women and 24 men, mean age 61 years (median 58, range 37-80).

RESULTS

Of 95 aneurysms, 86 had been discovered incidentally, 3 were symptomatic and 6 were additional to another ruptured aneurysm. Location was anterior communicating artery 33, middle cerebral artery 29, basilar tip 19, carotid tip 8, posterior communicating artery 4, posterior inferior cerebellar artery 1, superior cerebellar artery 1. Mean aneurysm size was 6 mm (median 6, range 3-13 mm).In one aneurysm additional coils were used and in another, a stent was placed. There was one procedural rupture without clinical sequelae. There were two thrombo-embolic complications leading to permanent deficit in one patient (mRS 2). Morbidity rate was 1.0% (1 of 93, 95%CI 0.01-6.5%) and mortality was 0% (0 of 93, 95%CI 0.0-4.8%). Angiographic follow-up at six months was available in 85 patients with 87 aneurysms (91%). Of 87 aneurysms, 68 (78%) were completely occluded, 14 (16%) had a neck remnant and 5 were incompletely occluded. Four aneurysms were retreated. Retreatment rate was 4.5% (4 of 87, 95%CI 1.7-13.6%).

CONCLUSION

WEB treatment of unruptured aneurysms is safe and effective. Additional devices are needed only rarely and retreatment at follow-up is infrequent.

Implantation of Large Diameter (5.5-6 mm) Derivo Embolization Devices for the Treatment of Cerebral Aneurysms

BACKGROUND

The efficacy of flow diverters is dependent upon robust wall apposition in the parent artery. Usage in large caliber cerebral vessels has therefore been limited as few implants with diameters > 5 mm exist. We present our initial experience in treating cerebral aneurysms using the 5.5 mm and 6 mm diameter implants of the Derivo embolization device (DED).

METHODS

Our prospectively maintained institutional database was reviewed to identify patients in whom a > 5 mm DED was implanted between November 2016 and February 2021. The primary efficacy outcome was complete or near-complete aneurysm occlusion at 6 months (O'Kelly-Marotta, OKM, C-D, adapted for magnetic resonance angiography). Safety outcomes included 30-day major morbidity defined as modified Rankin Score (mRS) 3-5, mortality, serious adverse events and procedural complications.

RESULTS

A total of 21 large diameter DEDs were deployed in 18 patients (age 59.5 ± 14.1 years), harboring 19 unruptured aneurysms. Of the aneurysms 14 (73.7%) were saccular in morphology (sac diameter 10.9 ± 5.5 mm, neck diameter 6.8 ± 3.1 mm), 3 (15.8%) aneurysms were dissecting, 1 (5.3%) iatrogenic pseudoaneurysm and 1 (5.3%) fusiform. Aneurysm locations were: ICA (internal carotid artery) (n = 17); (7 cavernous, 4 paraophthalmic, 2 paraclinoid, 1 petrous, 2 communicating, 1 cervical); vertebrobasilar (n = 2). Adjunct stenting to optimize proximal wall apposition was undertaken in 5 (27.8%) patients. At 6 months 75% of patients followed-up met the primary efficacy endpoint (OKM C-D). There were no serious adverse events, 30-day major morbidity (mRS 3-5) or mortality.

CONCLUSION

Implantation of large diameter (5.5 mm and 6 mm) DEDs into capacious cerebral vessels to treat a range of complex aneurysms is safe and technically feasible but may require adjunct stenting to optimize proximal wall apposition. Short-term efficacy of this device subset is comparable to previous DED and other flow diverter studies. Long-term follow-up and comparative studies are required for further assessment.

A realistic way to investigate the design, and mechanical properties of flow diverter stents

PURPOSE

Braided flow diverters (FD) are highly sophisticated, delicate, and intricate mechanical devices used to treat intracranial aneurysms. Testing such devices in vitro, however, remains an unsolved challenge. Here, we evaluate methods to measure flow, design and mechanical properties in vitro.

METHODS

Flow properties, cell porosity, pore density, and cell area were evaluated under geometrically realistic conditions by placing FDs in patient-derived, 3D-printed models of human vasculature. 4D flow MRI was used to measure fluid dynamics. Laser microscopy was used to measure the design properties of the FDs. New methods were developed to investigate the bending, circumferential, and longitudinal radial force of the FDs continuously over varying diameters.

RESULTS

The placement and flow properties of the FD in the vasculature models were successfully measured by MRI, although artifacts occurred. Likewise, the porosity, pore density, and cell area were successfully measured inside of the models using a laser microscope. The newly developed mechanical methods allowed to measure the indicated forces - to our knowledge for the first time - continuously.

CONCLUSION

Modern and specifically tailored techniques, some of which were presented here for the first time, allow detailed insights into the flow, design, and mechanical properties of braided flow diverter stents.

Triggering of Carotid Sinus Reflex during Deployment of the Flow-diverter Device

The carotid sinus reflex (CSR) is a rare complication of the Pipeline Embolization Device (PED) deployment. No study has assessed the potential risk factors in a case series. The purpose of this study was to examine CSR triggering during PED deployment. Thirty-seven consecutive patients who underwent PED deployment were included. All procedures were performed under local anesthesia with mild sedation. We retrospectively analyzed patient characteristics, PED deployment time, and vital signs during the procedure. The vital signs included the pulse rate (PR) and systolic blood pressure (SBP) obtained at three timepoints (pre-deployment, during deployment, post-deployment). We examined the triggering of the CSR during PED deployment by comparing the vital signs at the three timepoints. Moreover, risk factors for CSR were analyzed with univariate analysis. The patients’ average age was 66.3 years. The average size of the aneurysm was 18.0 mm. Six patients (16.2%) showed a decline in the SBP or PR defined as CSR. One patient had a transient cardiac arrest and two had severe transient bradycardia. Deployment into the ophthalmic segment of the internal carotid artery (C2 segment) aneurysm (p = 0.022), prolonged PED deployment time more than 14.5 minutes (p = 0.005), and an acute angle of the anterior genu less than 51.5 degrees (p = 0.005) were risk factors in triggering CSR. CSR may be triggered during PED deployment under local anesthesia with mild sedation. Deployment to the C2 segment aneurysm, prolonged PED deployment time, and an acute angle of the anterior genu were associated with CSR triggering.

Thromboelastography (TEG) results are predictive of ischemic and hemorrhagic complications in patients with unruptured intracranial aneurysms treated with flow diversion

INTRODUCTION

Flow diversion is an effective treatment modality for intracranial aneurysms but is associated with ischemic and hemorrhagic complications. Patients treated with flow diversion require dual antiplatelet therapy and subsequent platelet function tests. At our institution, Thromboelastography with Platelet Mapping (TEG-PM) is the test of choice. The primary objective of this study was to identify TEG parameters that are predictive of postoperative complications in patients treated with elective flow diversion.

METHODS

This was a retrospective study of 118 patients with unruptured intracranial aneurysms treated with flow diversion. Data was collected via chart review. Bivariate analyses were performed to identify significant variables in patients who suffered an ischemic stroke or a groin hematoma. ROC curves were constructed for the TEG parameters with statistical significance. Bivariate analyses were repeated using dichotomized TEG results.

RESULTS

Patients who experienced a symptomatic ischemic stroke had a history of stroke (p value = 0.007), larger aneurysm neck width (p value = 0.017), and a higher alpha angle (p value = 0.013). Cut off point for ischemic complication is 63° on ROC curve with a sensitivity of 100% and specificity of 65%. Patients who experienced a groin hematoma were no different from their healthy peers but had a lower alpha angle (p value = 0.033). Cut off point for hemorrhagic complication is 53.3° with a sensitivity of 82% and specificity of 67%.

CONCLUSION

The Alpha Angle parameter of TEG-PM has a sizeable predictive ability for both ischemic complications of the central nervous system and hemorrhagic complications of the access site after elective flow diversion.

"Trapped labelled spins"-related signal on arterial spin labelling in the assessment of flow-diverted aneurysms: preliminary experience

PURPOSE

To investigate ASL-MRI features of flow-diverted aneurysms, review their haemodynamic surrogates, and discuss their pertinent clinical implications.

METHODS

Retrospective single institutional analysis was performed on the clinical and imaging data of patients who underwent digital subtraction angiography (DSA) and ASL-MRI after endovascular flow diversion for cerebral aneurysms. Pseudo-continuous ASL-MRI was performed with post-label delays of 1525-1800 ms. Intra-aneurysmal "trapped labelled spins" (TLS)-related hypersignal, as seen on cerebral blood flow (CBF)-weighted maps of ASL-MRI, was investigated. Intermodality equivalence with DSA [O'Kelly-Marotta (OKM) grading for occlusion], 3D-TOF-MRA, and 3D spin-echo T1-weighted ("black-blood") images was assessed.

RESULTS

Ten cases were included. "TLS" signal was demonstrable in 7/8 (87.5%) of the DSA-visible flow-diverted aneurysms (OKM grade B3, n = 6; OKM grade A3, n = 2). No TLS was seen in both OKM-D (excluded) aneurysms. TLS was not visualised in an OKM-B3 aneurysm with < 3 mm opacifying remnant. 3D-TOF-MRA and ASL-MRI were discordant at 5 instances (45.4%; TOF-MRA false negative, n = 4; false positive, n = 1). Loss of flow void on black-blood images corresponded to the absence of TLS and vice versa in all cases but one.

CONCLUSION

"Trapped labelled spins"-related signal on ASL-MRI occurs in patent large aneurysms that have undergone successful endovascular flow diversion. This phenomenon likely represents an interplay of a multitude of haemodynamic factors including decelerated intra-aneurysmal inflow and outflow restriction. Serial intra-saccular TLS signal changes may hold diagnostic value, including contexts where 3D-TOF-MRA interpretation becomes dubious. "Trapped labelled spins"-related signal as a non-invasive proxy marker of aneurysm patency can possibly obviate unnecessary DSA.

L-Arginine reduces downstream vascular contractility after flow-diverting device deployment: A preliminary study in a rabbit model

BACKGROUND

Flow diverters (FDs) are an effective treatment for intracranial aneurysms, though not free from hemorrhagic complications. A previous study demonstrated increased vascular contractility after FD-implantation as a potential mechanism of distal complications. Our study aimed to investigate whether L-arginine medication affects vascular contractility following FD deployment in a rabbit model.

METHODS

FDs were implanted in the aorta of normal rabbits (+FD, n = 10), with sham-operated aorta as controls (n = 5). L-Arginine was given in the drinking water (2.25% L-arginine hydrochloride) of half of the +FD animals (+FD/+Arg). Force contraction vascular contractility studies were performed on the aortic rings proximal and distal to the FD using an organ bath. Total eNOS, eNOS(pS1177), eNOS(pT495), COX-2, and S100A4 were quantified by western analysis on total protein lysates from aortic segments, normalizing to GAPDH.

RESULTS

Mean vascular contractility was 53% higher in distal relative to proximal aortic segments (P = 0.0038) in +FD animals, but were not significantly different in +FD/+Arg animals, or in sham-operated controls. The +FD animals expressed significantly reduced levels of eNOS(pS1177) than sham-operated controls (P = 0.0335), while both the +FD and +FD/+Arg groups had reduced levels of eNOS(pT495) relative to sham-operated controls (P = 0.0331 and P = 0.0311, respectively).

CONCLUSION

These results suggest that L-arginine medication reduces distal vascular contractility after FD treatment via nitric oxide production and thus might mitigate risk for downstream complications.