Safety and efficacy of flow redirection endoluminal device (FRED) for treatment of intracranial aneurysm; A systematic review and meta-analysis.

BACKGROUND: Previous research has shown promising results for treating intracranial aneurysms (IAs) with a flow redirection endoluminal device (FRED). In this systematic review and meta-analysis, we aimed to assess the safety and efficacy of this device by providing pooled estimates using the data from previous studies. METHODS: A systematic literature search of Web of Sciences, PubMed, Scopus, and Embase was performed until October 8th, 2023. After selecting the final articles, relevant data were extracted. Parameters relating to safety and efficacy were pooled using STATA software. Heterogeneity was assessed using I-squared and Cochran's Q. Funnel plots and Egger's regression methods were used to evaluate publication bias. Sensitivity analysis was also performed using the leave-one-out method. RESULTS: The data of 37 studies were used for meta-analysis. The rates of immediate adequate occlusion and complete occlusion were 0.51 (95% CI: 0.31-0.71) and 0.34 (95% CI: 0.16-0.53), respectively, while the rates of the adequate and complete occlusion at the latest follow-up were 0.90 (95% CI: 0.84-0.94) and 0.75 (95% CI: 0.65-0.84), respectively. The periprocedural complications rate was 0.04 (95% CI: 0.03-0.06), and the overall complications rate was 0.12 (95% CI: 0.09-0.15). The rate of good functional outcome was 0.99 (95% CI: 0.99-1.00) and the successful implantation rate was 1.00 (95% CI: 1.00-1.00). There was substantial heterogeneity among the reports for most of the evaluated parameters. CONCLUSION: FRED had high safety and efficacy in treating IAs, as evidenced by its high occlusion and low complication rates.

Neurological outcomes of flow-diverter stent placement for middle cerebral artery aneurysms, with reference to the effects of argatroban on ischemic events: patient series.

BACKGROUND: A systematic review and meta-analysis of flow-diverter stents (FDSs) for the treatment of middle cerebral artery (MCA) aneurysms reported concerns about ischemic complications during treatment. The authors report on the intraoperative and postoperative complications of unruptured MCA aneurysms and their control strategies at their hospital, with detailed information on the aneurysms and a review of the previous literature. OBSERVATIONS: Intraoperative and perioperative in-stent thrombus occlusion occurred in 3 (37.5%) of the 8 patients evaluated. In cases with in-stent thrombus formation, rapid administration of 10 mg argatroban led to improvement in blood flow, as seen on angiography. Only 1 patient (12.5%) had a symptomatic stroke postoperatively. This patient was admitted for rehabilitation and drug therapy but was discharged from the hospital 10 days postoperatively with a modified Rankin Scale (mRS) score of 1. The patient had an mRS score of 0 at 90 days after surgery and at the last observation. LESSONS: Ischemic complications require attention during FDS treatment for MCA aneurysms. The use of argatroban in cases of in-stent thrombosis may contribute to a good neurological prognosis. https://thejns.org/doi/10.3171/CASE24237.

Pure arterial malformation of the fetal PCA treated with flow diverter stent-case report and literature review.

INTRODUCTION: Thirty-three-year-old female underwent diagnostic work-up for chronic headaches. CASE REPORT: Cerebral DSA on the right side showed fetal posterior cerebral artery (PCA) with unusually shaped arterial malformation on its proximal part. Malformation was formed by multiple convolutions and loops with no arteriovenous shunting. During endovascular procedure, flow diverter stent was placed in the right C6 segment. Patient was put on double antiaggregation therapy. Four weeks after procedure, patient was admitted to ER with signs of dyphasia. No recent ischemic lesions were detected on emergent magnetic resonance. Dyphasia resolved spontaneously. On follow-up magnetic resonance angiography 5 years after the procedure, main portion of malformation has diminished with slightly filling of posterior part supplied by right P1. DISCUSSION: Here, reported finding is consistent with previously described pure arterial malformation (PAM). Main intention of our treatment was to induce malformation remodeling with flow diverter placement. Two main risks arise when using flow diverters on fetal PCA region. Firstly, there is possibility of occluding fetal PCA alongside malformation. On the contrary, high flow through fetal PCA could hinder malformation thrombosis. Some case series reported high rate of fetal PCA occlusion without ischemic sequelae in the PCA teritory. Others consider flow diverters highly ineffective treatment for the fetal PCA aneurysms due to low rate of complete aneurysm occlusion. CONCLUSION: We presented first reported case in which flow diverter was used to treat PAM. Slow malformation thrombosis leaves enough time for collateral circulation to recruit and supply territory of the vessel affected by the malformation.

Flow diversion with hydrophilic polymer coating with prasugrel as single antiplatelet therapy in the treatment of acutely ruptured intracranial aneurysms: a multicenter case series, complication and occlusion rates.

BACKGROUND: This study reports a multicenter experience of using hydrophilic polymer-coated (HPC) flow diverters with prasugrel single antiplatelet therapy to treat ruptured aneurysms with subarachnoid hemorrhage (SAH). METHODS: Patients treated for intracranial aneurysms within 30 days after SAH with a p64/p48 MW HPC flow diverter were prospectively identified. Clinical presentation and outcomes, periprocedural and postprocedural complications, and degree of occlusion at follow-up were evaluated. RESULTS: A total of 84 patients were treated in 88 sessions (54.5% women; mean age 53.3 years). Four patients (4.7%) experienced flow diverter-dependent complications. No cases of aneurysm re-rupture or hemorrhagic complications related to antiplatelet therapy were recorded. Immediate complete occlusion was achieved in 27.4% of cases (23/84). The rate of complete occlusion among survivors was 83% in early follow-up, 90.2% in mid-term follow-up, and 92.3% in the latest possible follow-up. CONCLUSION: p64/p48 MW HPC flow diverters with prasugrel single antiplatelet therapy were associated with safety from aneurysm re-rupture and high occlusion rates at medium- and long-term follow-up in managing ruptured aneurysms. Adequate management of single antiplatelet therapy with prasugrel is crucial, particularly with higher doses than usual, to avoid both ischemic and hemorrhagic complications.

Half-dose ticagrelor versus standard-dose clopidogrel in a dual antiplatelet regimen for stent-assisted coiling or flow diversion of unruptured intracranial aneurysms: a cohort study.

BACKGROUND: Intracranial hemorrhage is the major safety concern of standard-dose ticagrelor (90 mg twice daily) based dual antiplatelet therapy (DAPT). The bleeding avoidance strategy through dose de-escalation has been investigated in interventional cardiology. However, the preserved antithrombotic efficacy and better safety of half-dose (45 mg twice daily) ticagrelor remains unverified in patients undergoing stent-assist coiling (SAC) or flow diversion (FD) treating unruptured intracranial aneurysms (UIA). METHODS: A single-center, prospective, cohort study was conducted to compare DAPT with aspirin 100 mg daily plus half-dose ticagrelor vs standard-dose clopidogrel (75 mg daily) in UIA patients. The adenosine diphosphate inhibition (ADPi) rate was utilized to quantify the antagonization of adenosine diphosphate (ADP)-induced platelet aggregation. The patients were followed-up at 6 month after discharge. The primary efficacy outcome was the major adverse cardiovascular and cerebrovascular events (MACCE), and the primary safety outcome was major bleeding. The secondary outcome was minor hemorrhage. RESULTS: Our study included 322 UIA patients, of which 254 patients were eventually enrolled after propensity score matching. The ADPi of half-dose ticagrelor (51.56%±31.46%) was comparable (P=0.089) to that of clopidogrel (57.44%±22.76%). The outcomes were also comparable. Five (3.94%) patients in the ticagrelor group and eight (6.30%) patients in the clopidogrel group reported MACCE (P=0.393). One patient in the ticagrelor group was diagnosed with asymptomatic intracranial hemorrhage 1 month after stenting. There were 36 (28.35%) minor hemorrhagic events in the ticagrelor group and 35 (27.56%) in the clopidogrel group, (P=0.889). CONCLUSION: Half-dose ticagrelor was effective and safe as a potential alternative to clopidogrel in the DAPT regimen for patients undergoing SAC/FD for UIA.

The impact of delivery technique on Woven EndoBridge deployment and detachment in an in vitro aneurysm model.

BACKGROUND: The Woven EndoBridge (WEB) device is increasingly used for treatment of wide-neck bifurcation aneurysms. With the newer 17 system, WEB deployment has been associated with a phenomenon known as incomplete or "sticky" detachment from the delivery wire, which may lead to imprecise placement. Optimal techniques for WEB manipulation and delivery to avoid this problem are poorly defined. This study aimed to evaluate standard WEB deployment techniques and determine the impact of delivery techniques and WEB stickiness on procedural success. METHODS: An in vitro study using identical silicone middle cerebral artery aneurysm models (n = 32) assessed WEB (6 × 2 mm) deployment through a VIA 17 microcatheter via three techniques that involved: "loading," "neutral," and "tension" on the pusher wire. Microcatheter position was placed in varied positions from the WEB device. Woven EndoBridge stickiness was graded during detachment attempts. Primary outcomes were detachment stickiness and attempt number, compared between techniques using Fisher's exact test. RESULTS: The tension technique resulted in significantly fewer sticky detachments and detachment attempts compared to forward load or neutral techniques (p < 0.001). Sticky detachment was lower with tension (0% sticky) versus forward load (42% sticky, 8% very sticky) (p < 0.001). Forward load had a 50% rate of stickiness versus 0% with tension and neutral (p < 0.001). Forward load required multiple attempts in 100%, compared to 57% with neutral and 8% with tension (p < 0.001). Higher stickiness grades increased the need for multiple attempts (p < 0.001). CONCLUSION: The tension technique reduces incomplete WEB detachment and enables precise single-attempt detachment, optimizing delivery precision. In vivo confirmation is needed.

The DERIVO 2 Heal Embolization Device in the Treatment of Ruptured and Unruptured Intracranial Aneurysms: a Retrospective Multicenter Study.

BACKROUND: The use of flow diverting stents in the treatment of intracranial aneurysms is associated with a risk of neurological morbidity due to their thrombogenicity. To reduce this risk different surface modifications have been developed. The Derivo 2 Embolization Device (Acandis, Pforzheim, Germany) has proven to be a safe and effective flow diverter. To overcome the risk of thrombo-embolism, the device was modified by adding an anti-thrombogenic fibrin-heparin coating. We aimed to assess the safety and effectiveness of the Derivo 2 heal Embolization Device. METHODS: Retrospective multicenter data from nine German neurovascular centers between February 2022 until December 2023 were used. Patients treated with the Derivo 2 heal Embolization Device for unruptured or ruptured intracranial aneurysms were included. Peri- and postprocedural adverse events, clinical outcomes, and angiographic follow-up results were evaluated. RESULTS: 84 patients (73.8% female; mean age 58.7 years) with 89 aneurysms (mean size 9.8 mm) were included. 87.6% were located in the anterior circulation. Most of them were sidewall aneurysms (88.8%). 96 flow diverters were used. 99.0% were successfully implanted. An in-stent balloon angioplasty was performed in 6.0% of the cases. An additional coiling was performed in 28.6%. Technical difficulties were present in 12.0% of the cases. Thrombotic events occurred in 4.8% with no neurological sequelae. Mortality and morbidity were 0 and 1.2% respectively. Adequate aneurysm occlusion was achieved in 80.7% with a mean follow-up time of 6.6 months. CONCLUSION: The Derivo 2 heal Embolization Device showed a satisfying aneurysm occlusion and safety with a low rate of neurological morbidity.

Image Follow-Up After Flow Diverter Treatment Using Only Ultra-High Resolution CT Angiography with Model-Based Iterative Reconstruction: A Case Report.

Follow-up examinations using magnetic resonance imaging or digital subtraction angiography are mandatory after flow diverter treatment of cerebral aneurysms. However, flow diverter features metal artifacts on magnetic resonance imaging and ischemic complications with digital subtraction angiography. Ultra-high-resolution computed tomography systems have recently become available in clinical practice. The combined use of ultra-high-resolution computed tomography and a reconstruction technique called model-based iterative reconstruction is expected to replace follow-up magnetic resonance imaging and digital subtraction angiography of flow diverter placement. Here, we report a case of ultra-high-resolution computed tomography with model-based iterative reconstruction after flow diverter treatment.

Micro-WADA and balloon test occlusion for sacrifice of distal P2 aneurysm.

Here we present a fusiform, partially thrombosed, previously ruptured aneurysm in the posterior cerebral artery that was treated with parent vessel sacrifice after a micro-WADA and micro-balloon test occlusion (video 1). These aneurysms pose treatment challenges due to their deep location, morphology, and potentially eloquent distal supply.1 2 Primary coiling, stent assisted coiling, or microsurgical clipping are often not viable options, whereas flow diversion, parent vessel sacrifice,3 or trapping with bypass are usually employed. Pharmacological provocative testing via a micro-WADA4 5 with or without a micro-balloon test occlusion is critical to establish whether the territory at risk has functional eloquence, although specific reports for using these techniques are limited. We describe the patient presentation, initial treatment attempt and failure, and our protocol for performing a micro-WADA/balloon test occlusion test.neurintsurg;jnis-2024-022058v1/V1F1V1Video 1 Micro wada for PCA aneurysm.

Bifurcation dissecting aneurysm: tips and tricks to differentiate from saccular aneurysm.

Bifurcations are a common site for saccular aneurysms, but rarely can be a site for dissecting aneurysms. Identification of these aneurysms is extremely important because the management plan depends on it. We describe a rare case of a ruptured dissecting aneurysm at the right ICA bifurcation in a pre-teen child which posed a diagnostic dilemma but ultimately was successfully managed with flow diversion.

Treatment of medullary aneurysm in the collateral circulation with a flow diverter: A case report.

INTRODUCTION AND IMPORTANCE: Spinal aneurysms rarely occur in the collateral circulation of the vertebral artery (VA). These aneurysms are difficult to treat. A flow diverter (FD) can be a therapeutic option. CASE PRESENTATION: A 62-year-old man suffered subarachnoid hemorrhage. His Hunt-Hess scale classification was grade II. Digital subtraction angiography (DSA) revealed that the bilateral distal VAs were occluded, there were two flow-related aneurysms in the collateral circulation of the first radicular artery of the VA, and there was a dissecting aneurysm at the origin of the posterior inferior cerebellar artery (PICA). The FD covered the PICA dissecting aneurysm, and the first radicular artery originated in the VA. Postoperatively, computed tomography angiography revealed a patent PICA and regression of the aneurysm in the collateral circulation. At the one-month follow-up, he showed good recovery and was therefore allowed to return to work. Follow-up DSA confirmed the regression of the aneurysms. However, the intracranial VA and PICA were unexpectedly occluded. CLINICAL DISCUSSION: It is difficult to catheterize aneurysms in the collateral circulation to perform coiling. It is also dangerous to embolize such aneurysms with a liquid embolic agent. After FD deployment to cover the origin of the parent artery, the hemodynamic stress of the aneurysm decreases, and the aneurysm can regress. CONCLUSION: Aneurysms in the collateral circulation were not accessible. FD deployment in the parent artery to cover the origin of the feeding artery of the collateral circulation is feasible for treating such aneurysms.

Pipeline versus non-pipeline flow diverter treatment for M1 aneurysms: A systematic review and meta-analysis.

BACKGROUND: The flow diversion treatment of aneurysms located distal to the Circle of Willis has recently increased in frequency. We conducted a systematic review and meta-analysis of the clinical and radiological outcomes of flow diverter (FD) embolization in treating M1 aneurysms. METHODS: PubMed, Web of Science, Ovid Medline, Ovid Embase, and Scopus were searched up to May 2024 using the Nested Knowledge platform. We included studies assessing the long-term clinical and radiological outcomes for M1 aneurysms. Results of FDs classified as Pipeline Embolization Devices (PED) versus other types of FDs. Angiographic occlusion rates, ischemic and hemorrhagic complications, and favorable clinic outcomes were included. All data were analyzed using R software version 4.2.2. RESULTS: Thirteen studies with 112 total patients (58 patients for PED and 54 patients for other FD devices) were included in our meta-analysis. The overall adequate (complete + near-complete) occlusion rates were 85.1%. The complete occlusion rate was higher with PED than with other FD devices (72.9% PED and 41.6% for non-PED FDs, respectively, p-value <.01). The ischemic complications were 9.9% and 9.0% for the PED and non-PED groups, respectively (p-value = .89). The overall modified Rankin Scale 0-2 was 100% for the non-PED and 97.1% for the PED group (p-value = .51). In-stent stenosis rate was 7.5% for PED devices compared to 2.6% in the non-PED group (p-value = .35). CONCLUSIONS: This relatively small meta-analysis showed high rates of adequate and complete occlusion in FD treatment of M1 segment aneurysms, with favorable safety profiles. PEDs were associated with higher rates of complete aneurysm occlusion compared to other types of FDs.

Microsurgical and endovascular treatment of large and giant aneurysms of the anterior circulation: A systematic review.

Introduction: Large and Giant intracranial aneurysms (LGIAs) have become the paradigm for which endovascular techniques do not provide satisfactory results. Yet, microsurgery is followed by non-negligible rates of morbimortality. This scenario may have changed since the introduction of flow-diversion devices. Research question: Contemporary and standardised revision on microsurgical and endovascular results, with emphasis on anterior circulation LGIAs. Materials and methods: A systematic literature search was conducted in two databases (PubMed and Embase) on treatment outcomes of LGIAs of the anterior circulation, after the introduction of flow-diverters 2008/01/01, till 2023/05/20. Small case series (<5 cases), series including >15% of posterior circulation aneurysms, and studies not reporting clinical and/or angiographic outcomes were excluded. Results: 44 relevant studies (observational cohorts) were identified, including 2923 LGIAs predominantly from anterior circulation. Mean follow-up 22 (±20) months. 1494 (51%) LGIAs were treated endovascularly and 1427 (49%) microsurgically. According to the random effects model, pooled rates of favourable clinical outcomes were 85.8% (CI 95% 82.6-88.4), complete occlusion 69.4% (CI 95% 63.7-7.46), complications 19.6% (CI 95%16-23.9) and mortality 5.6% (CI 95% 4.4-7.1). Focusing on type of treatment, occlusion rates are higher with microsurgical (842/993, 85% vs 874/1,299, 67%), although good outcomes are slightly more frequent with endovascular (1045/1,135, 92% vs 1120/1,294, 87%). Discussion and conclusions: According to contemporary data about occlusion rates, functional outcomes, and complications, primary or secondary treatment of LGIAs of the anterior circulation seems justified. Microsurgical occlusion rates are higher in LGIAs. An expert consensus on reporting complications and management strategies is warranted.

Pipeline Vantage Embolization Device for the treatment of intracranial aneurysms: A systematic review and meta-analysis.

OBJECTIVE: The Pipeline Vantage Embolization Device (PVED) is a novel coated flow diverter with reduced wire diameters to improve neoendothelialization and stent porosity. This systematic review evaluates the safety and efficacy of the PVED based on the current literature. METHODS: Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, a thorough literature search was conducted using PubMed, EMBASE, and Cochrane. The random effects model was used to calculate estimates with major neurological complications within 30 days of treatment as the primary safety endpoint and ≤1-year complete occlusion rate as the primary efficacy endpoint. RESULTS: Six single-arm studies (5 retrospective, 1 prospective) with 392 patients and 439 aneurysms (6.8% ruptured) were included. Antiplatelet regimens varied, but dual antiplatelet therapy was administered in the majority. The pooled technical success rate was 99.0% (95%CI, 98.0%-100%) with an average of 1.2 devices implanted per procedure. Balloon angioplasty was performed in 17.0% (95%CI, 6.4-27.6%) and adjunctive coiling in 28.0% (95%CI, 17.8-38.2%), with significant heterogeneity for both variables. Pooled estimates for major neurological complications were 3.5% (95%CI, 1.7%-5.2%) with total ischemic events in 4.1% (95% CI, 1.6%-6.6%) and hemorrhagic events in 1.0% (95% CI, 0.0%-1.9%). The rate of complete angiographic occlusion was 75.7% (95%CI, 70.7%-80.6%) at a mean follow-up of 7 months, with in-stent stenoses in 8.1% (95%CI, 4.5%-11.8%). CONCLUSIONS: The safety and efficacy profile of the PVED appears comparable to competing devices, with potentially fewer complications than first-generation flow diverters. Long-term and comparative studies are needed to further confirm these results.

Endovascular Treatment of "Donut-Shaped" Aneurysm-A Case Series.

Background and Objectives: Partially thrombosed aneurysms represent a subset primarily found within large and giant aneurysms. The presence of an intraluminal thrombus can cause an aneurysm to present in different shapes upon angiographic examination. We present a series of five cases of "donut-shaped" aneurysms observed over the past decade at the Clinic for Neurosurgery in the University Clinical Centre of Serbia. Materials and Methods: The management of "donut-shaped" aneurysms was accomplished through endovascular interventions, employing techniques such as the deployment of flow-diverting stents or a combination of stent placement and coil embolization. Results: Four out of five patients underwent endovascular treatment, yielding positive outcomes with complete thrombosis of the aneurysms during follow-up. The fifth patient was successfully diagnosed; however, due to their deteriorating condition, treatment was not feasible. Conclusions: Given the potential life-threatening complications associated with this entity, accurate diagnosis and appropriate management are crucial. In our cohort, endovascular interventions demonstrated efficacy in the majority of cases, underscoring the significance of this approach in treating "donut-shaped" aneurysms. Nevertheless, considering the rarity of this condition, further research is justified to refine diagnostic and therapeutic strategies for these complex intracranial vascular anomalies.

Comparative Efficacy of Flow Diverter Devices in the Treatment of Carotid Sidewall Intracranial Aneurysms: a Retrospective, Multicenter Study.

BACKGROUND: The comparative efficacy and safety of first-generation flow diverters (FDs), Pipeline Embolization Device (PED) (Medtronic, Irvine, California), Silk (Balt Extrusion, Montmorency, France), Flow Re-direction Endoluminal Device (FRED) (Microvention, Tustin, California), and Surpass Streamline (Stryker Neurovascular, Fremont, California), is not directly established and largely inferred. PURPOSE: This study aimed to compare the efficacy of different FDs in treating sidewall ICA intracranial aneurysms. METHODS: We conducted a retrospective review of prospectively maintained databases from eighteen academic institutions from 2009-2016, comprising 444 patients treated with one of four devices for sidewall ICA aneurysms. Data on demographics, aneurysm characteristics, treatment outcomes, and complications were analyzed. Angiographic and clinical outcomes were assessed using various imaging modalities and modified Rankin Scale (mRS). Propensity score weighting was employed to balance confounding variables. The data analysis used Kaplan-Meier curves, logistic regression, and Cox proportional-hazards regression. RESULTS: While there were no significant differences in retreatment rates, functional outcomes (mRS 0-1), and thromboembolic complications between the four devices, the probability of achieving adequate occlusion at the last follow-up was highest in Surpass device (HR: 4.59; CI: 2.75-7.66, p < 0.001), followed by FRED (HR: 2.23; CI: 1.44-3.46, p < 0.001), PED (HR: 1.72; CI: 1.10-2.70, p = 0.018), and Silk (HR: 1.0 ref. standard). The only hemorrhagic complications were with Surpass (1%). CONCLUSION: All the first-generation devices achieved good clinical outcomes and retreatment rates in treating ICA sidewall aneurysms. Prospective studies are needed to explore the nuanced differences between these devices in the long term.

Innovations in intracranial aneurysm treatment: a pilot study on the Choydar flow diverter.

Background: The flow diverter (FD) has emerged as a promising treatment option for intracranial aneurysms. Recently, a novel flow-diverting stent, the Choydar FD device, has been developed within our nation. Objective: To introduce the newly developed Choydar FD device and present our preliminary clinical experience with its application in the treatment of intracranial aneurysms. Methods: A total of 23 patients with 23 unruptured intracranial aneurysms, comprising 20 (87.0%) aneurysms located at the internal carotid artery and 3 (13.0%) at the vertebral artery, were treated with the Choydar FD device between December 2021 and April 2022. Patient baseline data, clinical and angiographic outcomes were collected and analyzed. Results: The Choydar FD device was successfully deployed in all patients (100%), with 18 aneurysms (78.3%) additionally treated with coils. One patient experienced an ischemic event with sensory disturbance during the perioperative period. At the 1-year follow-up, all patients demonstrated good clinical outcomes. Of the 23 aneurysms with available angiographic follow-up, 22 (95.7%) achieved complete occlusion, and one patient exhibited in-stent stenosis without neurological deficits. Conclusion: The initial clinical results of the Choydar FD device are encouraging, and it appears to be a useful option for treating intracranial aneurysms with acceptable efficacy and safety. Future studies with larger sample sizes and longer follow-up durations are warranted to validate these findings.

It Is Necessary to Pay Attention to Where the Pcom Originate from the Aneurysm to Treat with FD.

Objective With the expansion of indications of flow diverter (FD) for cerebral aneurysms, FD placement for posterior communicating artery (Pcom) aneurysms has been approved. However, it is controversial whether Pcom aneurysms should be treated with FD or not. In this study, we report the outcome of FD treatment for Pcom aneurysms in Japan. Materials and Methods We retrospectively analyzed 36 patients with 38 aneurysms treated with FD placement for Pcom aneurysms between 2015 and 2021 in our hospital. We divided our cases into complete occlusion (CO) and non-CO groups. And we extracted contributing factors to CO using multivariate analysis. We also compared the complications rate among the three types of FDs. Results CO was obtained in 29 cases (79.3%), and complications were observed in 3 cases (7.9%). Multivariate analysis revealed that the type of Pcom branch from the aneurysmal dome was a significant factor contributing to CO (odds ratio: 0.0052, 95% confidence interval 0.000048-0.584, p = 0.029). In terms of complications, complication rate was significantly higher in the Flow-Redirection Endoluminal Device (FRED) group ( p = 0.0491). Conclusion The outcome for Pcom aneurysms treated by FD was acceptable. When treating, we must pay attention to where Pcom originates. Achieving CO with FD is difficult for aneurysms where the Pcom branches from the dome. Furthermore, when treating Pcom aneurysms with FRED, it is necessary to be careful about thromboembolic complications.

In vitro evaluation of flow diverter performance using a human fibrinogen-based flow model.

OBJECTIVE: Fibrin deposition represents a key step in aneurysm occlusion, promoting endothelization of implants and connective tissue organization as part of the aneurysm-healing mechanism. In this study, the authors introduce a novel in vitro testing platform for flow diverters based on human fibrinogen. METHODS: A flow diverter was deployed in 4 different glass models. The glass models had the same internal parent artery (4 mm) and aneurysm (8 mm) diameters with varying parent artery angulations (paraophthalmic, sidewall, bifurcation, and slightly curved models). The neck size and area were 4 mm and 25 mm2, respectively. Human fibrinogen (330 mg/dl) was circulated within the glass models at varying flow rates (0, 3, 4, and 5 ml/sec) with or without heparin, calcium chloride, and thrombin for as long as 6 hours or until complete fibrin coverage of the flow diverter's neck was achieved. Aneurysm neck coverage was defined as macroscopic fibrin deposition occluding the flow diverters' pores. Flow characteristics after flow diverter deployment were assessed with computational fluid dynamics analysis. The effects of flow rates, heparin, calcium chloride, and thrombin on fibrin deposition rates were tested using 1-way ANOVA and the Tukey test. RESULTS: A total of 84 replicates were performed. Human fibrin did not accumulate on the flow diverter stents under static conditions. The fibrin deposition rate on the aneurysm neck was significantly greater with the 5 ml/sec flow rate as compared to 3 ml/sec for all models. The paraophthalmic model had the highest inflow velocity of 48.7 cm/sec. The bifurcation model had the highest maximum shear stress (SS) and maximum normalized shear stress values at the device cells at 843.3 dyne/cm2 and 35.1 SS/SSinflow, respectively. The fibrin deposition rates of the paraophthalmic and bifurcation models were significantly higher than those of sidewall and slightly curved models for all additive or flow rate comparisons (p = 0.001 for all comparisons). The incorporation of thrombin significantly increased the fibrin deposition rates across all models (p = 0.001 for all models). CONCLUSIONS: Rates of fibrin deposition varied widely across different configurations and additive conditions in this novel in vitro model system. Fibrin accumulation started at the aneurysm inflow zone where flow velocity and shear stress were the highest. The primary factors influencing fibrin deposition included flow velocities, shear stress, and the addition of thrombin at a physiological concentration. Further research is needed to test the clinical utility of fibrinogen-based models for patient-specific aneurysms.