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To analyze the effect of tirofiban on ischemic events in CYP2C19 loss-of-function (LOF) allele carriers during pipeline embolization device (PED) implantation. Demographic information, imaging data, ischemic complications, CYP2C19 genotyping, and platelet function test results were collected from patients with PED-treated intracranial aneurysms at three centers. Multivariate logistic regression was used to analyze risk factors for ischemic events. Patients were grouped according to LOF alleles and antiplatelet drugs, the baseline information of LOF allele carriers and non-carriers were compared, and the efficacy of tirofiban was analyzed by comparing the incidence of ischemic events in each group. In total, 278 patients were included in the study, 24 of whom had an ischemic event. 157 (56.5%) patients carried the LOF allele and were more likely to develop resistance to clopidogrel (P < 0.001) and hypertension (P = 0.010). Multivariate logistic regression analysis revealed that the independent risk factors for ischemic events were age of > 55 years (OR = 3.308, P = 0.028), LOF alleles (OR = 3.960, P = 0.036), and clopidogrel nonresponsiveness (OR = 3.301, P = 0.014). For LOF allele carriers, prophylactic use of tirofiban after PED implantation helped to reduce ischemic events (4.3% vs. 16.4%, P = 0.039). This study supports CYP2C19 genotyping before flow diversion because LOF alleles increase the risk of ischemic events. Prophylactic use of tirofiban may help reduce ischemic events in LOF allele carriers. [ABSTRACT FROM AUTHOR]

Background: Endovascular management for vertebral artery dissecting aneurysms (VADA) is quite intricate which thereby necessitate different strategies per case. Our current study described various optimal strategies available for endovascular management of VADA other than flow diverter (FD). Results: 14 Patients presented with acute SAH and 4 patients with symptoms of mass effect. VADA were classified in 3 groups, viz contralateral vertebral artery is dominant group A (n = 5), co-dominant group B (n = 8) or group C hypoplastic (n = 5). Group A and B (n = 13) was further subdivided into three subtypes depending on location of aneurysm with respect to posterior inferior cerebellar artery (PICA), aneurysm proximal to the PICA, type I (n = 5); involving the PICA, type II (n = 1); and distal to the pica, type III (n = 4). Treatment strategy varied with type whether deconstructive or reconstructive methods using stents and coils in different fashion. Conclusion: Preprocedural angiographic work up delineating the anatomical location of the aneurysm, contralateral vertebral artery dominancy and nearby perforator status along with location of PICA is imperative in selecting the safest and optimal endovascular therapy option. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Treatment of complex wide neck internal carotid aneurysm is technically difficult with both surgical as well as endovascular therapy. In this study, we work with flow diverter device to construct vascular lumen which diverts the blood flow from aneurysm sac. Case presentation: We report on two patients with two complex wide neck ruptured aneurysms located in the internal carotid artery associated with two small aneurysms who presented with severe headache and vomiting. All aneurysms were treated with single Surpass Evolve flow diverter (SE-FD) placement. Post-procedural clinical and angiographic outcomes were evaluated Conclusion: This study shows that Surpass Evolve flow diverter is safe and validity for management of complex wide neck internal carotid artery aneurysm and able to terminate all blister aneurysms associated with the parent artery. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this registry was to assess technical success, procedural safety and mid- to long-term follow-up results of the Silk Vista "Mama" (SVM) flow diverter (BALT, Montmorency, France) for the treatment of proximal intracranial aneurysms. Methods: Between August 2020 and March 2022, data from nine Italian neurovascular centres were collected. Data included patients' clinical presentation, aneurysms' size, location and status, technical details, overall complications and mid- to long-term angiographic follow-up. Results: Forty-eight aneurysms in 48 patients were treated using the SVM. Most aneurysms were small (≤ 10 mm: no. 29, 60%) and unruptured (no. 31, 65%); 13 aneurysms were recurrent after coiling or clipping. 37/48 aneurysms involved the internal carotid artery (77%). Optimal opening and complete wall apposition of the device were achieved in 46 out of 48 cases (96%). Four intra- or periprocedural complications occurred (two thrombotic complications successfully resolved, one cerebellar ischemia, one perirenal hematoma), without new neurological deficit. No significant intra-stent stenosis or stent displacement was observed during follow-up. No FD-related morbidity nor mortality was reported. At midterm (6–12 months) to long-term (> 12 months) follow-up, complete aneurysm occlusion (OKM D) was achieved in 76% of cases. Eighty-eight percent of patients had complete aneurysm occlusion or entry remnant (OKM D + C). Conclusions: Our experience suggests that the new generation of low-profile SVM flow diverter for the treatment of proximal intracranial aneurysms is safe and effective, with low rates of intraprocedural complications and acceptable mid- to long-term occlusion rate. [ABSTRACT FROM AUTHOR]

Purpose: In China, the application of nitinol Tubridge flow diverter (TFD) has become popular for treating intracranial aneurysms (IAs). In this study, we investigated the safety outcomes of the application of TFD for treating IAs in real-world scenarios. Methods: We retrospectively analyzed aneurysms treated with TFD in 235 centers throughout China between April 2018 and April 2020. The primary endpoint was the event-free survival rate at 12 months, defined as the occurrence of morbidity (spontaneous rupture, intraparenchymal hemorrhage (IPH), ischemic stroke, and permanent cranial neuropathy) or death. Univariate and multivariate analyses were performed to assess the risk factors. A good outcome was defined as a modified Rankin Score (mRS) of 0–2. Results: We included 1281 unruptured aneurysms treated with TFD. The overall neurological morbidity and death rates after 12 months were 5.4 and 2.8%, respectively. Ischemic strokes were the most common complication (4.2%, P < 0.001). Cranial neuropathy, IPH, and spontaneous rupture occurred in 0.3%, 0.3%, and 0.5% of aneurysms, respectively. Univariate and multivariate analyses indicated that the male gender, older age, larger aneurysm diameter, and aneurysm located on BA were the independent risk factors for neurologic events. Aneurysm located on BA was the independent risk factor for ischemic strokes. Most patients (1222) had access to the mRS, and 93.2% of them achieved good outcomes. Conclusion: Treatment of IAs with TFD was associated with low morbidity and mortality, most of which were ischemic events. Large posterior aneurysms might be associated with a higher complication rate. Trial Registration: Retrospectively registered. [ABSTRACT FROM AUTHOR]

Cerebral aneurysm is a life-threatening condition, which requires high precision during the neurosurgical procedures. Increasing progress of evaluating modern devices in medicine have led to common usage of robotic systems in many fields, including cranial aneurysm operations. However, currently no systematic review describes up-to date knowledge of this topic. Following PRISMA guidelines, we have independently screened and extracted works from seven databases. Only studies fulfilling inclusion criteria were presented in this study. Device used, operation time, complications, aneurysm type and patient demographics were extracted from each work. We identified a total of 995 articles from databases. We have found six original works and one supplementary article eligible for this synthesis. Majority of works (4/6) have implemented CorPath GRX in cerebral aneurysm procedures. The procedures involved diverse aneurysm locations, utilizing flow diverters, stents, or coiling. One study described implementation of robot-assist on 117 patients and compared results to randomized clinical trials. One work with a small patient cohort described use of the magnetically-controlled microguidewire in the coiling procedures, without any complications. Additionally, one case-series study described use of a robotic arm for managing intraoperative aneurysm rupture. Currently, robotical devices for cerebral aneurysm treatment mainly lack jailing and haptic feedback feature. Further development of these devices will certainly be beneficial for operators and patients, allowing for more precise and remote surgeries. [ABSTRACT FROM AUTHOR]

Background: The use of antithrombotic medication following acute flow diversion for a ruptured intracranial aneurysm (IA) is challenging with no current guidelines. We investigated the incidence of treatment-related complications and patient outcomes after flow diversion for a ruptured IA before and after the implementation of a standardized antithrombotic medication protocol. Methods: We conducted a single-center retrospective study including consecutive patients treated for acutely ruptured IAs with flow diversion during 2015–2023. We divided the patients into two groups: those treated before the implementation of the protocol (pre-protocol) and those treated after the implementation of the protocol (post-protocol). The primary outcomes were hemorrhagic and ischemic complications. A secondary outcome was clinical outcome using the modified Ranking Scale (mRS). Results: Totally 39 patients with 40 ruptured IAs were treated with flow diversion (69% pre-protocol, 31% post-protocol). The patient mean age was 55 years, 62% were female, 63% of aneurysms were in the posterior circulation, 92% of aneurysms were non-saccular, and 44% were in poor grade on admission. Treatment differences included the use of glycoprotein IIb/IIIa inhibitors (pre-group 48% vs. post-group 100%), and the use of early dual antiplatelets (pre-group 44% vs. 92% post-group). The incidence of ischemic complications was 37% and 42% and the incidence of hemorrhagic complications was 30% and 33% in the pre- and post-groups, respectively, with no between-group differences. There were three (11%) aneurysm re-ruptures in the pre-group and none in the post-group. There were no differences in mortality or mRS 0–2 between the groups at 6 months. Conclusion: We found no major differences in the incidence of ischemic or hemorrhagic complications after the implementation of a standardized antithrombotic protocol for acute flow diversion for ruptured IAs. There is an urgent need for more evidence-based guidelines to optimize antithrombotic treatment after flow diversion in the setting of subarachnoid hemorrhage. [ABSTRACT FROM AUTHOR]

Few studies have explored the effect of a flow-diverter device (FD) on blood flow in the A1 segment of the anterior cerebral artery (ACA), after treatment of intracranial aneurysms in the bifurcation region of the internal carotid artery (ICA). The main objective of this article is to investigate the factors that affect A1 blood flow after FD covers the A1 artery. This is a single-center, retrospective study. Data were collected retrospectively from our center, and patients whose FDs were placed for treatment from the terminal of the ICA to the M1 segment were analyzed. A total of 42 patients were included in the study. Immediate post-procedural angiography following device placement revealed decreased blood flow in the A1 of 15 (35.7%) patients and complete occlusion of the A1 segment in 11 (26.2%) patients. During an average follow-up period of 9.8 months, the A1 segment was ultimately occluded in 25 patients (59.5%) and decreased blood flow in 4 patients (9.5%). When using FD to cover the A1 artery for the treatment of intracranial aneurysms, patients with preoperative opening of the anterior communicating artery (AcomA) are more prone to occlusion or decreased blood flow of the A1 artery, compared to patients without opening. [ABSTRACT FROM AUTHOR]

We present a case of ultra-early symptomatic fish-mouth type stenosis (FMTS) of a Surpass Evolve flow diverter stent (SE-FDS) occurring within 24 h after deployment for the treatment of multiple unruptured right siphon aneurysms in a 44-year-old patient. The patient developed left hemiplegia and hemineglect, and was treated with mechanical thrombectomy (MT) and Tirofiban infusion. This is the first report of an ultra-early FMTS with a SE-FDS and its mechanism is discussed in the light of available data in the literature. [ABSTRACT FROM AUTHOR]

The introduction of flow diverters (FDs) has represented a paradigm shift in the management of unruptured cerebral aneurysms (UCA). Flow Re-direction Endoluminal Devices (FREDs) and Pipeline Embolization Devices (PEDs) have gained widespread popularity. We aimed to investigate the cumulative incidence of aneurysm occlusion. A total of 195 patients with 199 UCAs were analyzed retrospectively. The outcomes were aneurysmal occlusion during the follow-up, a modified Rankin Scale score of 0–2 at 90 days, additional treatment, major stroke, and steno-occlusive events of FD. Propensity score-matched analysis was performed, controlling for age, sex, aneurysmal size, and location of the internal carotid artery (ICA) aneurysm. Non-ICA aneurysms were excluded from matching. During the follow-up period (median, 366 days), complete and satisfactory aneurysmal occlusions were observed in 128 (68%) and 148 (78%) of 189 UCAs in the unmatched cohort. The 142 (71 each) propensity score-matched cohort was complied. The FRED group had a higher cumulative incidence of ICA aneurysm occlusion (complete: HR 2.7, 95% CI 1.4–5.1, p = 0.0025; satisfactory: HR 2.4, 95% CI 1.1–5.2, p = 0.025). The proportion of additional treatment was significantly smaller in the FRED group (OR 0.077, 95% CI 0.010–0.57, p = 0.0007). Other outcomes showed no significant differences. Propensity score-matched analysis indicated that FRED might have a higher cumulative incidence of aneurysmal occlusion in the treatment of unruptured ICA aneurysms. Whether a cumulative incidence of aneurysmal occlusion may differ by the type of FDs warrants further investigation. [ABSTRACT FROM AUTHOR]

Purpose: Intracranial vertebral artery dissecting aneurysm (IVADA) is a rare type of aneurysm with high morbidity and mortality. Recently, the application of pipeline embolization devices (PEDs) has been extended to IVADAs. Here, we aim to investigate the safety and effectiveness of PEDs for IVADAs. Method: We retrospectively reviewed the PLUS database to identify patients who had IVADAs and were treated with PEDs from 2014 to 2019 at 14 centers across China. Data including patient and aneurysm characteristics, procedure details, angiographic and clinical results, relationship with the ipsilateral posterior inferior cerebellar artery (PICA), and patency of the PICA following PED coverage were analyzed. Results: In this study 52 consecutive patients with 52 IVADAs were included. The mean age was 52.33 years and 82.7% were male. With a median follow-up of 10.5 months, the complete occlusion rate was 93.8% (45/48) and no recurrence or in-stent stenosis was detected. The total postoperative complication rate and mortality were 11.5% and 1.9%, respectively. Complications occurred in 9.6% (5/52) of patients within 30 days after the operation, including ischemic stroke in 3 and hemorrhagic stroke in 2. Another patient suffered an ischemic stroke at follow-up, 78.8% (41/52) PICAs were covered by PEDs, 1 case (2.4%) had a functional disability due to PICA occlusion, while 39.0% (16/41) had reduced flow during follow-up but hardly caused any obvious neurological deficits. Patients with IVADA involving PICA had a trend towards more complications (66.7% vs. 51.1%; P = 1). Conclusion: Treating IVADAs with PEDs may be a safe and effective option, with favorable clinical and angiographic outcomes; however, complications associated with this treatment should not be ignored. Registration: http://www.clinicaltrials.gov. Unique identifier: NCT03831672 [ABSTRACT FROM AUTHOR]

Purpose: Follow-up examinations after flow diverter (FD) treatment for cerebral aneurysms typically involve magnetic resonance imaging (MRI) or digital subtraction angiography (DSA). However, MRI is prone to vascular defects due to metal artifacts from FD, and DSA carries a risk of ischemic complications. In the context of computed tomography angiography (CTA), this study compares the efficacy of ultra-high-resolution CT (UHRCT) and novel reconstruction techniques, such as model-based iterative reconstruction (MBIR), against conventional methods such as filtered back projection (FBP) and hybrid iterative reconstruction (IR), to determine if they are a viable alternative to DSA in clinical settings. Materials and methods: A phantom study was conducted with the full-width half-maximum considered as the FD thickness. This study compared three reconstruction methods: MBIR, FBP, and hybrid IR. A clinical study was also conducted with 21 patients who underwent follow-up CTA after FD treatment. The FD's visibility was assessed using a 4-point scale in FBP, hybrid IR, and MBIR compared to cone-beam CT (CBCT) with angiographic systems. Results: In the phantom study, FBP, hybrid IR, and MBIR visualized thinner FD thicknesses and improved detail rendering in that order. MBIR proved to be significantly superior in both the phantom and clinical study. Conclusion: UHRCT with MBIR is highly effective for follow-up evaluations after FD treatment and may become the first-choice modality in the future. [ABSTRACT FROM AUTHOR]

Purpose: To assess the safety and short-term occlusion rates in procedures using the p64 MW hydrophilic polymer-coated (HPC) flow diverter (FD) with prasugrel single antiplatelet therapy (SAPT) for the treatment of anterior circulation saccular aneurysms. Methods: We retrospectively identified patients who underwent treatment of one or more intracranial anterior circulation saccular aneurysms between March 2020 and December 2021 with a p64 MW HPC FD and prasugrel SAPT with verified P2Y12 platelet receptor inhibition. Patients diagnosed with fusiform, dissecting, or recently ruptured aneurysms were excluded. Periprocedural and postprocedural complications, clinical outcomes, and angiographic follow-up results were evaluated. Results: One hundred and two patients with 132 intracranial aneurysms met the inclusion criteria. Previous or concomitant treatments (e.g., coil occlusion) had been performed on 18 of these aneurysms. The technical success rate (i.e., implantation of the intended FD) was 100% with an average of 1.1 devices implanted per patient. Periprocedural and postprocedural complications occurred in 13.6% and 6.8% of these patients, respectively. No mortality or permanent clinical deterioration (i.e., modified Rankin scale score ≥ 3) were reported. Early follow-up digital subtraction angiography revealed aneurysmal occlusion rates of 72.6% and 83.8% at four and nine months, respectively. Conclusions: The implantation of a p64 MW HPC FD with prasugrel SAPT is safe and results in rapid, reliable and effective aneurysmal occlusion. [ABSTRACT FROM AUTHOR]

Objective: The morphological changes of the pipeline embolization device (PED; Medtronic, Minneapolis, MN, USA), such as delayed migration or foreshortening, can relate to the incomplete occlusion of aneurysms. Case presentation: A 30-year-old man with a giant cavernous carotid artery aneurysm was treated with two PEDs using the overlapping technique. Six months after treatment, follow-up angiography showed morphological changes of the PEDs and residual flow into the aneurysm. Chronological cone-beam computed tomography fusion imaging clearly revealed the dynamic foreshortening of the first PED and the disconnection of both PEDs, so we decided to implant an additional PED. Conclusion: This case illustrates that a three-dimensional understanding can be useful for assessing the cause of treatment failure or recurrence. [ABSTRACT FROM AUTHOR]

Purpose: The Flow Re-direction Endoluminal Device (FRED) has recently become available for flow diversion in Japan. We have encountered cases that failed to deploy the FRED. In this study, we report our initial experience with the FRED for cerebral aneurysms and clarify the causes of failed FRED deployment. Methods: A retrospective data analysis was performed to identify patients treated with the FRED between June 2020 and March 2021. Follow-up digital subtraction angiography was performed at 3 and 6 months and assessed using the O'Kelly-Marotta (OKM) grading scale. Results: Thirty-nine aneurysms in 36 patients (average age: 54.4 years) were treated with the FRED. The average sizes of the dome and neck were 9.9 mm and 5.2 mm, respectively. In nine patients, additional coiling was performed. In one patient (2.6%), proximal vessel injury caused direct carotid-cavernous fistula during deployment. Ischaemic complications were encountered in one patient (2.6%) with transient symptoms. Angiographic follow-up at 6 months revealed OKM grade C or D in 86.6% of patients. FRED deployment was successful in 35 (92.1%) procedures. In the failure group, the differences between the FRED and the minimum vessel diameter (P = 0.04) and the rate of the parent vessel having an S-shaped curve (P = 0.04) were greater than those in the success group. Conclusions: Flow diversion using the FRED is effective and safe for treating cerebral aneurysms. The use of the FRED for patients with an S-shaped curve in the parent vessel and oversizing of more than 2 mm should be considered carefully. [ABSTRACT FROM AUTHOR]

In the treatment of an intracranial aneurysm with the flow diverter, the combined use of coil embolization can help promote subsequent progressive thrombosis within the aneurysm sac and reduce the risk of delayed aneurysm rupture. This study retrospectively reviewed outcomes of patients who had undergone the Pipeline Embolization Device (PED) with adjunctive coil embolization (PED/coil) at a single center to determine its safety and efficiency. Patients with internal carotid artery aneurysms following an intradural component were selected for PED/coil between 2015 and 2020. All patients were premedicated with dual antiplatelet therapy of aspirin plus clopidogrel or prasugrel. A minimal number of PEDs were deployed, with coils inserted using a stent-jail technique, avoiding dense packing. A total of 46 aneurysms (43 patients; median dome size, 11.6 mm; median neck width, 6.3 mm) were treated with PED/coil. The median volume embolization ratio was 14.8%. The degree of angiographic filling at the 6-month and latest angiography showed complete occlusion in 60.5% (26/43) and 70.5% (31/44), respectively. Small (< 10 mm) aneurysms achieved a higher complete occlusion rate in the early period; a lower cumulative incidence of aneurysm occlusion was observed in large and giant (≥ 10 mm) aneurysms (P =.024). The median clinical follow-up was 22 months, and no aneurysm ruptures occurred. Favorable clinical outcomes were achieved, with permanent neurological morbidity of 4.7% and no mortality. PED/coil demonstrated a high angiographic occlusion rate at an early stage. Loosely packed coils are sufficient to obliterate aneurysms effectively. [ABSTRACT FROM AUTHOR]

Purpose: Flow diverter stents are gaining wider use in the treatment of complex intracranial aneurysms; however, there are limited data on occlusion and complication rates of flow diverters in very large and giant aneurysms. This study assessed the safety and efficacy of flow redirection endoluminal device (FRED) and FRED Jr. stents in aneurysms ≥ 20 mm. Methods: We retrospectively analyzed all aneurysms ≥ 20 mm treated with FRED/FRED Jr. between January 2010 and June 2020 from three centers. Endpoints for clinical safety were absence of major stroke, aneurysmal rupture, or death and complete or near-complete occlusion for efficacy. Results: A total of 45 patients with very large (28 cases) and giant aneurysms (17 cases) were treated with FRED (41 cases), and FRED Jr. (4 cases) stents. The majority of the aneurysms (40/45, 88.9%) were in the anterior circulation. Adjunctive aneurysm coiling was performed in 21 aneurysms (46.7%). Technical complications were encountered in 4 procedures (8.9%). Ischemic and hemorrhagic complication rates were 6.7% and 8.9%, respectively. There was no case with major stroke. The mortality rate was 8.9%, and all cases were due to hemorrhagic complications from aneurysmal rupture. Median angiographic follow-up was 21.5 months (range 3–60 months). Complete occlusion was achieved in 32 aneurysms (71.1%), and near-complete occlusion in 5 cases (11.1%). Conclusion: The use of FRED/FRED Jr. for the treatment of aneurysms ≥ 20 mm achieved a long-term aneurysm occlusion rate and a safety profile comparable to the large series reported with other flow diverter stents. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the outcomes of flow-diverting device (FDD) treatment for large vertebral artery dissecting aneurysms (VADAs). Methods: This retrospective study evaluated 12 patients with 12 VADAs who were treated using FDD between 2013 and 2020. Clinical and radiographic data, including procedure-related complications and clinical outcomes assessed using the modified Rankin Scale (mRS) at the time of the last follow-up, were collected and reviewed. Results: All 12 patients had unruptured aneurysms. There were 3 (25%) female and 9 (75%) male patients, and the mean patient age was 54.6 years. The mean size of the aneurysm was 15.9 ± 4.8 mm. The mean follow-up duration was 15.8 months. Single FDD without additional coils was used in all patients. One patient underwent second-line treatment with FDD for recurrence of large VADA after stent-assisted coiling. Immediate follow-up angiography after placement of the FDD demonstrated intra-aneurysmal contrast stasis. There were 2 (17%) patients who had peri-procedural stroke. Angiography at the 6-month follow-up in 10 patients showed favorable occlusion (OKM grade C3 + D). A total of 11 (92%) patients had good clinical outcome (modified Rankin Scale ≤ 2) at the last follow-up. No re-treatment or delayed aneurysm rupture occurred during the follow-up period. Conclusions: Reconstructive technique with FDD is a feasible and effective modality for the treatment of large VADAs, showing favorable occlusion rate and clinical outcome. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Purpose: Current flow diverter (FD) designs limit the possibilities to achieve ideal functional parameters for intra-aneurysmal flow alteration in the implanted state. In this work, we evaluate the technical feasibility of a new patient-specific FD concept and the impact on intra-aneurysmal flow reduction compared to standard FD. Methods: Based on a literature review, we defined functional requirements, followed by the design and manufacturing of two different prototypes, which we implanted in a patient-specific phantom model. Functional porosity distributions and contour parameters were evaluated in the implanted state and compared to standard FD. Subsequently, we carried out a series of particle image velocimetry (PIV) measurements, in order to assess the impact on intra-aneurysmal flow. Results: With both patient-specific prototypes, it was possible to achieve stronger intra-aneurysmal flow reductions in terms of maximum and mean velocity and vorticity than a standard FD; however, one design showed a strong sensitivity against malpositioning. Overall, fluid dynamics parameters correlated with geometrical aspects such as the porosity and its grade of homogeneity. Beyond that, we found influences by the FD contour projection within the aneurysm, especially connected to the formation of in-jets. Conclusion: Our results show that there is a technically feasible concept, which enables a more specific adjustment of functional FD parameters and more effective intra-aneurysmal flow reduction. This could potentially lead to improvements in the efficacy of aneurysm occlusion in cases with challenging fluid dynamics. [ABSTRACT FROM AUTHOR]

Purpose: Endovascular treatment of unruptured intracranial aneurysms may increase cerebral microbleeds (CMBs) in postprocedural T2*-weighted MRIs, which may be a risk for future intracerebral hemorrhage. This study examined the characteristics of postprocedural CMBs and the factors that cause their increase. Methods: The patients who underwent endovascular treatment for unruptured intracranial aneurysms from April 2016 to February 2018 were retrospectively analyzed. Treatment techniques for endovascular treatment included simple coiling, balloon-assisted coiling, stent-assisted coiling, or flow diverter placement. To evaluate the increase in CMBs, a head MRI including diffusion-weighted imaging and T2*-weighted MRIs was performed on the preprocedural day; the first postprocedural day; and at 1, 3, and 6 months after the procedure. Results: Among the 101 aneurysms that were analyzed, 38 (37.6%) showed the appearance of new CMBs. In the multivariate analysis examining the causes of the CMB increases, chronic kidney disease, a higher number of preprocedural CMBs, and a higher number of diffusion-weighted imaging–positive lesions on the first postprocedural day were independent risk factors. Furthermore, a greater portion of the increased CMBs was found in cortical and subcortical lesions of the treated vascular perfusion area within 1 month after the procedure. Conclusion: In endovascular treatment for unruptured intracranial aneurysms, CMBs tended to increase in patients with small vessel disease before the procedure, and it was also implicated in hemorrhagic changes after periprocedural microinfarction. [ABSTRACT FROM AUTHOR]

Background and Purpose: The use of flow diverters to treat aneurysms arising from small caliber parent vessels has been reported. This article reports the results of the first in experiences with the p48MW (p48 Movable Wire) in humans, a device specifically designed to target vessels 1.75–3 mm in diameter. Methods: This monocentric study retrospectively reviewed the prospectively maintained database to identify all patients treated with the p48MW device between January 2017 and January 2019 at this institution. Patient demographics, aneurysm characteristics, angiographic and clinical follow-up were recorded as well as complications. Results: A total of 25 patients (20 female) with an average age of 55 ± 12.9 years (range 34–84) with 25 aneurysms were identified. The majority of the aneurysms was located in the anterior circulation (19/25, 76%). The average aneurysm dome width was 3.98 ± 3.6 mm (range 1.2–13 mm). Complete occlusion was seen in 18/24 (75%) aneurysms with neck remnants in 1/24 (4.2%) and continued aneurysm filling seen in the remaining cases (5/24, 20.8%). Adequate occlusion was seen in 79.2% of aneurysms (Raymond Roy Classification [RRC] grade I or II) during the follow-up period. There was a single technical complication with inappropriate deployment of the first p48MW. There was a single clinical complication (4%); however, the patient made a complete recovery (modified Rankin Scale [mRS] 0) and one patient died secondary to uncontrollable status epilepticus following acute subarachnoid hemorrhage unrelated to the treatment. Conclusion: The p48MW is safe and effective for the treatment of aneurysms including those arising from distal vessels. [ABSTRACT FROM AUTHOR]

Purpose: Flow diverters (FD) have poor radiopacity, challenging visualization of deployment and vessel wall apposition with conventional neuroimaging modalities. We evaluated a novel cone beam computed tomography (CT) imaging technique that allows virtual dilution (VD) of contrast media to facilitate workflow and ensure accurate assessment of FD wall apposition. Methods: We retrospectively evaluated all patients treated for intracranial aneurysms with FD at our institution between November 2018 and November 2019. Undiluted injected dual cone beam CT acquisitions performed post-stenting were displayed with VD software (GE Healthcare). The resulting images were compared with conventional two-dimensional (2D) digital subtraction angiography (DSA) images. Two neurointerventionalists (Reader 1 and Reader 2, (R1, R2)) independently assessed FD deployment and wall apposition. Confidence in the diagnosis, inter-reader agreement, and X-ray exposure were assessed. Results: A total of 27 cases were reviewed. FD deployment and wall apposition scores were 4.2 ± 1.0 (R1) and 4.0 ± 1.1 (R2) for DSA and 3.7 ± 1.2 (R1) and 4.1 ± 1.0 (R2) for VD. Confidence in the diagnosis was improved with VD, with scores of 3.7 ± 0.7 (R1) and 4.0 ± 0.7 (R2) using DSA and 4.9 ± 0.2 (R1) and 4.9 ± 0.2 (R2) using VD (P < 0.001). Inter-reader agreement using 2D DSA was improved from moderate (0.49324) to good (0.7272) (P < 0.0001). There were no significant differences in inter-reader agreement in the deployment assessment (P = 0.68) or dose-area product (P = 0.54) between techniques. Conclusion: VD imaging with dual cone beam CT enables accurate assessment of FD wall apposition after deployment with greater confidence and improved inter-reader agreement versus conventional 2D DSA alone, with comparable X-ray exposure. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to compare the treatment outcomes of large (15–25 mm) and giant (> 25 mm) intracranial aneurysms (IAs), according to different treatment modalities. Methods: In total, 112 patients with large and giant IAs treated with various treatment modalities between January 2009 and December 2018 were retrospectively reviewed. Clinical and radiological parameters were analyzed and correlated with the treatment modality. Results: A total of 141 procedures were performed on 112 patients. We initially treated 47 cases with coil embolization, 39 with flow diverter (FD), 13 with direct clipping, and 13 with parent artery occlusion (PAO). Recurrence (46.8%) and retreatment (31.9%) rates were significantly higher in the coiling group (p < 0.001). Complete occlusion rate (36.3%) was significantly lower in the coiling group (p = 0.027). PAO could achieve a high complete occlusion rate (90.9%) with low complication rate (12.5%). The total complication rate was 17%. In the multivariate logistic regression analysis, FD (OR 3.406, p = 0.036) and direct clipping (OR 5.732, p = 0.017) showed a significantly higher complication rate than coiling. The overall mortality rate was 8% (8/139 procedures). At the last follow-up (mean 30.6 ± 26.4 months), 70 of 96 patients (72.9%) showed complete or near-complete occlusion. Good functional outcome (mRS ≤ 2) was observed in 90 of 112 (80.3%) patients at the last follow-up (mean 33.2 ± 30.5 months). Conclusions: Good clinical and radiologic outcomes with acceptable complication and mortality rates can be achieved by various treatment modalities. The selection of appropriate modality should be individualized based on the angiographic findings and clinical symptoms. [ABSTRACT FROM AUTHOR]

Intracranial aneurysms are rarely diagnosed during pregnancy. If treatment is necessary, surgery was traditionally preferred over embolization in case of ongoing pregnancy, due to concerns regarding foetal radiation exposure. We present a case of 21 mm unruptured carotid-ophthalmic aneurysm diagnosed during pregnancy and treated with flow diversion. Foetal radiation dose was estimated between 1 and 5 mGy, well below recommended limits. Double antiplatelet therapy with prasugrel and aspirin was administered between week 17 and week 37, followed by uneventful vaginal delivery at 39 weeks. The new-born infant did not present any clinical abnormalities. Post-natal angiography showed complete aneurysm occlusion. To our knowledge, this is the first report of flow diverter stent placement during ongoing pregnancy. Although a good outcome was observed in this case, this result should be interpreted with caution. Further studies are needed in order to better define the safety profiles of intracranial stents and double antiplatelet therapies during pregnancy. [ABSTRACT FROM AUTHOR]

Purpose: The implantation of flow diverters requires administration of dual anti-platelet therapy, posing the potential for complications. The p48MW HPC (phenox, Bochüm, Germany) hydrophilic-coated flow diverting stent is designed to be anti-thrombotic, thus opening the potential for single anti-platelet therapy. We deploy a novel intravascular high-resolution imaging technique, high-frequency optical coherence tomography (HF-OCT), to study in an animal model the acute thrombus formation on coated p48MW devices versus uncoated control devices. Methods: Three pigs were implanted with 4 flow diverters each, two test hydrophilic-coated devices, and two control uncoated devices (p48MW). Each pig was treated with a different anti-platelet regime: no anti-platelet therapy, aspirin only, aspirin and clopidogrel. Twenty minutes after the flow diverter was implanted, an HF-OCT data set was acquired. Acute clot formed on the flow diverter at each covered side branch was measured from the HF-OCT slices. Factors considered to be important were the device type (pHPC versus bare metal), aspirin, clopidogrel, and vessel location. A linear model was constructed from the significant factors. Results: Both coating (p < 0.001) and aspirin (p = 0.003) were significantly related to reduction in clot burden, leading to an approximate 100-fold and 50-fold reduction in clot, respectively. Conclusions: This study shows the power of HF-OCT not only in the detection of clot but also the quantification of clot burden. In an animal model, the pHPC-coated p48MW significantly reduced acute thrombus formation over jailed side branches as compared to the bare metal p48MW that was nearly eliminated when combined with aspirin administration. [ABSTRACT FROM AUTHOR]

Background: In the last decade, flow diverter (FD) devices are one of the widely used endovascular methods in the treatment of intracranial aneurysms. As the frequency of its use is increasing progressively, we thought that studies concerned with the use of FD at specific locations are helpful to clarify the efficacy and safety of FD as a treatment option in cerebral aneurysms. We represent our experiences in the treatment of posterior communicating artery (PCOM) aneurysms by FD devices aiming to assess its angiographic efficacy (complete aneurysm occlusion) and its related complications. This is a retrospective study of 47 patients harboring 47 PCOM aneurysms treated with Pipeline Embolization Device (PED). Acutely ruptured and non-saccular aneurysms were excluded from the study. Short- and mid-term radiological and clinical outcomes were analyzed. Results: Procedure-related complications were observed in five patients (two ischemic events, two transient ischemic attacks (TIA), and one ipsilateral distal hemorrhage) with no procedure-related mortality. Complete aneurysm occlusion was encountered in 87.2%. In multivariable analysis, large-sized aneurysm and incorporated vessels were an independent predictor of non-occlusion (P = 0.026 and P = 0.035 respectively). A favorable clinical outcome (modified Rankin Scale, 0–2) was observed in 45/47 patients (95.7%); the incidence of postoperative complications was an independent predictor of unfavorable clinical outcomes (P = 0.048). Conclusion: PED stent provides a high occlusion rate in the treatment of PCOM aneurysms with good post-treatment clinical outcomes. [ABSTRACT FROM AUTHOR]

Background: Flow diversion (FD) remains a potential treatment option following aneurysmal subarachnoid hemorrhage (aSAH) when standard options may not be feasible. However, it should not be considered a first-line treatment due to the need for dual antiplatelet therapy (DAPT). The hydrophilic polymer coating on the p48MW flow diverter (HPC, phenox) is a surface modification that inhibits platelet adhesion. This study aims to report on our early single-center experience using the p48MW HPC (phenox) flow diverter with single antiplatelet therapy (SAPT) following an aSAH.Materials and Methods: We retrospectively identified all patients who had been treated with the p48MW HPC for aSAH under SAPT. All patients treated within 30 days following an aSAH were included. Any occurrence of thromboembolic and hemorrhagic complications was recorded alongside angiographic and clinical follow-up details.Results: Eight patients were identified. The mean interval between aSAH and FD was 6 days. Of the eight ruptured aneurysms, one was blister-like, one saccular, one mycotic, and the remaining five were dissecting aneurysms. Intraprocedural transient thrombus formation was observed in four patients (50%). Stent thrombosis was observed in one patient (12.5%) on day 3 with spontaneous recanalization after being switched onto DAPT. None of the aneurysms rebled after treatment. Two patients died due to cerebral vasospasm. Complete aneurysm occlusion had been achieved in all but one patient at angiographic follow-up (average 6 months).Conclusions: This small series highlights the possibility and limitations of using the p48MW HPC with SAPT in ruptured aneurysms. Randomized trials with longer follow-up in larger cohorts are underway. [ABSTRACT FROM AUTHOR]

Purpose: Intracranial aneurysms are malformations forming bulges on the walls of brain arteries. A flow diverter device is a fine braided wire structure used for the endovascular treatment of brain aneurysms. This work presents a rig and a protocol for the measurement of the hydrodynamic resistance of flow diverter stents. Hydrodynamic resistance is interpreted here as the pressure loss versus volumetric flow rate function through the mesh structure. The difficulty of the measurement is the very low flow rate range and the extreme sensitivity to contamination and disturbances. Methods: Rigorous attention was paid to reproducibility, hence a strict protocol was designed to ensure controlled circumstances and accuracy. Somewhat unusually, the history of the development of the rig, including the pitfalls was included in the paper. In addition to the hydrodynamic resistance measurements, the geometrical properties—metallic surface area, pore density, deployed and unconstrained length and diameter—of the stent deployment were measured. Results: Based on our evaluation method a confidence band can be determined for a given deployment scenario. Collectively analysing the hydrodynamic resistance and the geometric indices, a deeper understanding of an implantation can be obtained. Our results suggest that to correctly interpret the hydrodynamic resistance of a scenario, the deployment length has to be considered. To demonstrate the applicability of the measurement, as a pilot study the results of four intracranial flow diverter stents of two types and sizes have been reported in this work. The results of these measurements even on this small sample size provide valuable information on differences between stent types and deployment scenarios. [ABSTRACT FROM AUTHOR]

Background: Previous studies have not evaluated the impact of illness severity and postrupture procedures in the cost of care for intracranial aneurysms. We hypothesize that the severity of aneurysm rupture and the aggressiveness of postrupture interventions play a role in cost. Methods: The Value Driven Outcomes database was used to assess direct patient cost during the treatment of ruptured intracranial aneurysm with clipping, coiling, and Pipeline flow diverters. Results: One hundred ninety-eight patients (mean age 52.8 ± 14.1 years; 40.0% male) underwent craniotomy (64.6%), coiling (26.7%), or flow diversion (8.6%). Coiling was 1.4× more expensive than clipping (p =.005) and flow diversion was 1.7× more expensive than clipping (p <.001). More severe illness as measured by American Society of Anesthesia, Hunt/Hess, and Fisher scales incurred higher costs than less severe illness (p <.05). Use of a lumbar drain protocol to reduce subarachnoid hemorrhage and use of an external ventricular drain to manage intracranial pressure were associated with reduced (p =.05) and increased (p <.001) total costs, respectively. Patients with severe vasospasm (p <.005), those that received shunts (p <.001), and those who had complications (p <.001) had higher costs. Multivariate analysis showed that procedure type, length of stay, number of angiograms, vasospasm severity, disposition, and year of treatment were independent predictors of cost. Conclusions: These results show for the first time that disease and vasospasm severity and intensity of treatment directly impact the cost of care for patients with aneurysms in the USA. Strategies to alter these variables may prove important for cost reduction. [ABSTRACT FROM AUTHOR]

Background: Dual antiplatelet therapy is a pre-requisite for flow diverter (FD) implantation. The purpose of this study was to assess the thrombogenicity of the p48 FD, coated with the newly developed phenox Hydrophilic Polymer Coating (p48_HPC, phenox GmbH, Germany) in comparison with uncoated p48 FDs in an in vitro flow model (Chandler Loop).Methods: p48 and p48_HPC FDs were implanted into silicon tubes filled with whole human blood and incubated at 37 °C under pulsating flow. After 120 min, platelet count was determined in the blood. Platelet activation markers (PAR1) and formation of microparticles were analyzed in a flow cytometer. Fluorescence microscopy of CD42a positive cells and scanning electron microscopy was used to detect adherent platelets on the wire surface.Results: Platelets in contact with the uncoated p48 FDs are significantly more activated than those incubated with p48_HPC (73 ± 9% vs. 65 ± 6%, p < 0.05) and release more microparticles (1.8 ± 0.5 vs. 1.4 ± 0.4, p < 0.05). The platelet count after 120-min circulation in the Chandler Loop was significantly lower for the uncoated p48 compared to the p48_HPC indicating significantly greater adherence of the platelets to the p48 (71 ± 8% vs. 87 ± 5%, p < 0.05). SEM and fluorescent antibody imaging revealed minimal platelet adherence to the surface of the p48_HPC compared to the uncoated p48.Conclusion: The pHPC coating significantly reduces thrombogenicity of the p48 FD. This may help to reduce the risk of thromboembolic complications when using these devices. A reduction in antiplatelet therapy may be possible. [ABSTRACT FROM AUTHOR]

Purpose: It has been hypothesized that microstents which are used to prevent coil protrusion in the treatment of cerebral aneurysms may have flow diverting and therefore occlusive effects. In a rabbit elastase aneurysm model, we investigated the aneurysm occlusion rate and vessel reaction of a braided Accero stent prototype with porosity in the lower range of other available (non-flow-diverter) microstents.Methods: Ten aneurysms were induced the right subclavian artery in New Zealand white rabbits and treated with the Accero stent prototype. In each subject, a second stent was implanted in the abdominal aorta to cover the origins of branch arteries. Angiographic follow-up and explantation of the devices and aneurysms for histological analysis were performed after 3 months (n = 5) and 6 months (n = 5).Results: Grades I (< 50%) and II (> 50%) occlusion rates were observed in 9 (90%) and 1 (10%) of ten aneurysms treated with the stent device. The mean reduction in contrast filling at 6 months was 42.1% (p = .02). Neointima thickness was significantly higher in the subclavian artery than in the abdominal aorta after 3 (p = .03), whereas not after 6 months (p = .1). No cases of inadequate wall apposition, branch artery occlusion or stent thrombosis were observed.Conclusion: The present study showed flow remodelling properties of the device prototype with progredient aneurysm occlusion. A larger in vivo study with induced aneurysm should be done to confirm these results. [ABSTRACT FROM AUTHOR]

Purpose: Flow diverter (FD) devices show severe shortening during deployment in dependency of the vessel geometry. Valid information regarding the geometry of the targeted vessel is therefore mandatory for correct device selection, and to avoid complications. But the geometry of diseased tortuous intracranial vessels cannot be measured accurately with standard methods. The goal of this study is to prove the accuracy of a novel virtual stenting method in prediction of the behavior of a FD in an individual vessel geometry. Methods: We applied a virtual stenting method on angiographic 3D imaging data of the specific vasculature of patients, who underwent FD treatment. The planning tool analyzes the local vessel morphology and deploys the FD virtually. We measured in 18 cases the difference between simulated FD length and real FD length after treatment in a landmark-based registration of pre-/post-interventional 3D angiographic datasets. Results: The mean value of length deviation of the virtual FD was 2.2 mm (SD ± 1.9 mm) equaling 9.5% (SD ± 8.2%). Underestimated cases present lower deviations compared with overestimated FDs. Flow diverter cases with a nominal device length of 20 mm had the highest prediction accuracy. Conclusion: The results suggest that the virtual stenting method used in this study is capable of predicting FD length with a clinically sufficient accuracy in advance and could therefore be a helpful tool in intervention planning. Imaging data of high quality are mandatory, while processing and manipulation of the FD during the intervention may impact the accuracy. [ABSTRACT FROM AUTHOR]

Background: The region of the brain supplied by the anterior choroidal artery (AChoA) is exquisitely eloquent. Aneurysms arising at or close to the origin of the vessel are not uncommon and damage or occlusion to the vessel can result in devastating consequences. The optimal treatment strategy is yet to be determined. Objective: We sought to determine the efficacy of flow diversion for the treatment of unruptured AChoA aneurysms. Method: A retrospective review of our prospectively maintained database was performed to identify all patients with unruptured aneurysms of the AChoA between March 2009 and May 2017. The fundus size, number and type of flow-diverting stent (FD), complications and follow-up data were recorded. Results: We identified 30 patients (60% female), average age 52.8 ± 10.8 years (range 27–73), with 30 aneurysms. The aneurysms were generally small with a mean fundus diameter of 3.4 mm (range 1–7 mm). Early angiographic follow-up data were available for all patients at which point 15 aneurysms were completely occluded (50%). Delayed angiographic follow-up was available in 24 patients and occlusion was seen in 21 patients (87.5%). Of the patients one developed transient ischemic symptoms after interruption of the antiplatelet medication and another patient had a small embolic infarct with transient symptoms in the periprocedural period. Conclusion: Flow diversion can be used to successfully treat aneurysms of the AChoA. The treatment carries a high rate of technical and radiological success with a good safety profile. [ABSTRACT FROM AUTHOR]

A new approach to the assessment of interfering factors that arise in the process of diversion of a flow of liquid in the weighing device of a calibration device is presented. The uncertainty budget of the calibration device in reproduction of the unit of mass and unit of volume of liquid in a flow and unit of mass and unit of volume discharge of liquid is considered for this case. The operating principle of the calibration device is based on the method of static weighing. An assessment of the sources of uncertainty is performed by a pneumometric technique, which is itself based on an experimental determination of the local characteristics of the flow of liquid. [ABSTRACT FROM AUTHOR]

Purpose: There is limited information available on the incidence of in-stent stenosis (ISS) secondary to the use of flow-diverting stents in the intracranial vasculature. We sought to determine the incidence, severity, and clinical course of ISS on angiographic follow-up after treatment of saccular aneurysms with p64.Methods: We retrospectively reviewed all patients who underwent treatment of a saccular (ruptured and unruptured) intracranial aneurysm with ≥1 p64 between 2011 and 2015. Fusiform aneurysms and dissections were excluded. Aneurysms with prior or concomitant saccular treatment (e. g., coiling, clipping) were included. Extradural targets and aneurysms with parent vessel implants other than p64 were excluded. ISS was assessed on follow-up angiography and defined as <50% (mild), 50-75% (moderate), or >75% (severe).Results: In total, 205 patients (147 female, 71.7%; median age 57 years), with 223 saccular aneurysms were treated with p64 and had at least 9 months of digital subtraction angiography (DSA) follow-up completed. There was no DSA follow-up available in 8 patients. ISS of any degree at any time was recognized in 65/223 (29.1%) of all target aneurysms. The maximal degree of lumen loss was <50% in 40 lesions (17.9%), 50-75% in 19 lesions (8.5%), and >75% in 6 lesions (2.7%). ISS did not cause a focal neurological deficit in any patient. No progression from stenosis to occlusion was observed. Balloon angioplasty was performed in 1 lesion and was well tolerated. In 56 lesions (84.8%), a significant reduction of ISS occurred spontaneously, 2 mild stenoses remained stable, and for 6 lesions the long-term follow-up is pending.Conclusion: Treatment with p64 is associated with an overall rate of 8.5% moderate ISS (50-75%) and 2.7% severe ISS (>75%), which is comparable with the rate of ISS reported in the literature for other flow diverting stents. There is a tendency for ISS to spontaneously improve over time. [ABSTRACT FROM AUTHOR]

The supraclinoid ICA fenestration (SIF) is considered an extremely rare congenital anomaly. However, most of the reported cases of SIF are associated with intracranial aneurysms either ruptured or unruptured. We report the case of a 55-year-old patient with a right SIF and an unruptured, large, wide-necked aneurysm located on the larger limb of the fenestration and a second small aneurysm distal to the SIF. The aneurysms were treated with a Pipeline flow-diverter stent, achieving the complete reconstruction of the anatomy of the carotid siphon. The literature concerning these peculiar anatomic conditions has been reviewed, allowing discussion about treatment of such associated lesions. [ABSTRACT FROM AUTHOR]

Particle image velocimetry (PIV) is a commonly used method for in vitro investigation of fluid dynamics in biomedical devices, such as flow diverters for intracranial aneurysm treatment. Since it is limited to transparent blood substituting fluids like water-glycerol mixture, the influence of coagulation and platelet aggregation is neglected. We aimed at the development and the application of a modified platelet rich plasma as a new PIV fluid with blood-like rheological and coagulation properties. In standardized intracranial aneurysm silicone models, the effect of this new PIV plasma on the fluid dynamics before and after flow diverter implantation was evaluated and compared with water-glycerol measurements. The flow diverting effect was strongly dependent on the used fluid, with considerably lower velocities achieved using PIV plasma, despite the same starting viscosity of both fluids. Moreover, triggering coagulation of PIV plasma allowed for intra-aneurysmal clot formation. We presented the first in vitro PIV investigation using a non-Newtonian, clottable PIV plasma, demonstrating a mismatch to a standard PIV fluid and allowing for thrombus formation. [ABSTRACT FROM AUTHOR]

Purpose: The optimal strategy for the treatment of M1 segment aneurysms has not yet been determined as both standard microneurosurgical and endovascular techniques can pose challenges. We sought to determine the efficacy of flow diverting stents to treat small, unruptured aneurysms of the M1 segment.Methods: We retrospectively reviewed our database of prospectively collected information for all patients treated with flow diversion for an unruptured saccular aneurysm of the middle cerebral artery (MCA) between February 2009 and February 2016. The relationship to early cortical branches, aneurysm fundus size, number and type of flow diverting stent (FDS), complications and follow-up data were recorded.Results: In total 15 patients were identified that matched our inclusion criteria (11 female and 4 male). The average age of the patients was 58.3 years (range 14-76 years). All patients had a single aneurysm affecting the M1 segment of the MCA, 10 (66.6%) of which were related to early cortical branches and 10 aneurysms were located on the left (66.6%). The average aneurysm fundus size was 3 mm (range 2-9 mm) and 13 patients had follow-up angiographic studies. In total, 8 aneurysms were completely excluded, and 6 remained incompletely occluded (3 modified Raymond-Roy classification [mRRC] II and 3 mRRC IIIa). One patient suffered a stroke and another patient had an iatrogenic vessel dissection that was not flow limiting.Conclusion: Flow diversion can be used to treat small, unruptured aneurysms of the M1 segment of the MCA and even though side vessel occlusion can occur clinically relevant infarction occurs infrequently. [ABSTRACT FROM AUTHOR]

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Purpose: Flow diversion constitutes a pivotal advancement in endovascular intracranial aneurysm treatment, but requires development of a new skill set. The aim of this study is to determine whether outcomes after treatment with the Pipeline Embolization Device improve with experience. Methods: We retrospectively reviewed all patients with intracranial aneurysms treated with Pipeline at two centers over a 4.5-year period. Baseline patient and aneurysm characteristics, complications, and angiographic outcomes were analyzed. Results: One hundred forty patients underwent 150 Pipeline procedures to treat 167 intracranial aneurysms during the study period, 109 women, mean age 55.4 years. One hundred twenty-six aneurysms were ICA, mean size 10.2 mm and mean neck 6.4 mm. Intra-procedural technical difficulties were higher during the first 75 procedures compared with the subsequent 75 (13.3 vs 2.7%; p = 0.03), as combined major morbidity and neurological mortality (14.7 vs 4%; p = 0.046). In multivariate regression analysis, increased operator experience with Pipeline remained an independent predictor of intra-procedural technical difficulties ( p = 0.02, odds ratio (OR) 0.015, 95% CI 0.0004-0.55) and combined major morbidity and neurological mortality ( p = 0.03, OR 0.16, 95% CI 0.03-0.84). At last follow-up, 123 aneurysms were completely occluded (81.5%, mean 24 months). In our cohort, age ≤ 53 years was an independent predictor of complete aneurysm occlusion at last follow-up ( p = 0.001, OR 0.92, 95% CI 0.88-0.97). Five aneurysms were retreated (3.3%). Conclusion: The Pipeline embolization device is an effective treatment for intracranial aneurysms. The risk of intra-procedural technical difficulties and combined major morbidity and neurological mortality decreases significantly with increased operator experience in Pipeline deployment and patient management. [ABSTRACT FROM AUTHOR]

Purpose: Treatment of intracranial aneurysm with flow-diverting devices has become widespread in recent years. Despite that, intra-aneurysmal flow changes are yet not fully understood and can lead to different complications. Our aim was an in vitro contrast-based evaluation of the influence of flow diverter size and position on intra-aneurysmal flow dynamics. Methods: Flow-diverting devices with different sizes (diameters 4.0, 4.5, and 6.0 mm) were deployed in seven silicone aneurysm models at different positions relative to the aneurysm neck (proximal, central, distal). Using syngo iFlow, we defined quantitative evaluation criteria based on contrast medium intensity and performed a flow evaluation. Results: Intra-aneurysmal flows were heavily dependent on both size and position of flow-diverting devices at the aneurysm neck. We observed a higher peak intensity delay and intra-aneurysmal washout delay with the centrally placed 4.0- and 4.5-mm device, respectively, compared to the proximal and distal positions. Especially distally placed 4.0-mm devices led to an earlier filling of the aneurysm and increased intra-aneurysmal contrast agent intensity compared to the parent vessel, due to a potential endoleak. Conclusions: Not only size but also position of flow-diverting devices have a considerable impact on the intra-aneurysmal flow dynamics. The suggested evaluation criteria allowed a quantitative comparison of flow-diverting effect using syngo iFlow and could represent an efficient tool for predicting flow diversion pre-procedurally. [ABSTRACT FROM AUTHOR]

Purpose: Retrospective evaluation of our experience with the use of flow diverters (FD) for the endovascular treatment of direct carotid-cavernous sinus fistulae (diCCF). Methods: Between 2011 and 2015, 14 consecutive patients with 14 diCCF were treated with FD alone or in combination with other implants in a single institution. Results: A total of 21 sessions were performed in 14 patients. FD placement was technically successful in all cases without an adverse event. Patients were treated with FD alone ( n = 5), FD and covered stents ( n = 2), FD and coils ( n = 7). A total of 59 FD (24 Pipeline Embolization Device, Medtronic; 35 p64 Flow Modulation Device, phenox), 291 coils, and 3 stent grafts were used. Three of 14 diCCF were completely occluded after the 1 session, a minor residual shunt was found in 7/14, and in the remaining 4/14 patients, the shunt volume was reduced significantly. The mean follow-up period encompassed 20 months. Additional treatment included transvenous coil occlusion ( n = 3) and/or further FD deployment ( n = 5). An asymptomatic internal carotid artery (ICA) occlusion was encountered in 2 patients, related to an interruption of antiaggregation. At the last follow-up, 10/14 patients were free from ocular symptoms (71 %), 2 had residual exophthalmos, and no patient had clinical deterioration. Conclusion: The usage of FD for the treatment of diCCF is straightforward. Injury of the cranial nerves can be avoided. In most cases, ocular symptoms improve. Several FD layers and/or an adjunctive venous coil occlusion are required. Complete occlusion of a diCCF may take weeks or months and long-term antiaggregation is required. In the future, a flexible stent graft might be a better solution. [ABSTRACT FROM AUTHOR]

Purpose: Flow diverters are increasingly used in the treatment of complex and giant intracranial aneurysms. However, they are associated with complications like late aneurysmal rupture. Additionally, flow diverters show focal structural decrease in luminal diameter without any intimal hyperplasia. This resembles a 'fish mouth' when viewed en face. In this pilot study, we tested the hypothesis of a possible association between flow diverter fish-mouthing and delayed-type hypersensitivity to its metal constituents. Methods: We retrospectively reviewed patient records from our center between May 2010 and November 2015. A total of nine patients had flow diverter fish mouthing. A control group of 25 patients was selected. All study participants underwent prospective patch test to detect hypersensitivity to flow diverter metal constituents. Analysis was performed using logistic regression analysis and Wilcoxon sign rank sum test. Univariate and multivariate analyses were performed to test variables to predict flow diverter fish mouthing. Results: The association between flow diverter fish mouthing and positive patch test was not statistically significant. In multivariate analysis, history of allergy and maximum aneurysm size category was associated with flow diverter fish mouthing. This was further confirmed on Wilcoxon sign rank sum test. Conclusion: The study showed statistically significant association between flow diverter fish mouthing and history of contact allergy and a small aneurysmal size. Further large-scale studies are needed to detect a statistically significant association between flow diverter fish mouthing and patch test. We recommend early and more frequent follow-up imaging in patients with contact allergy to detect flow diverter fish mouthing and its subsequent evolution. [ABSTRACT FROM AUTHOR]

Purpose: Long-term data on aneurysm treatment with flow-diverting stents are still sparse, and follow-up protocols differ widely between institutions. We present long-term results, with a focus on the usefulness of contrast-enhanced MR angiography (ceMRA).Materials and Methods: Interventions and follow-up imaging of patients with aneurysms treated by flow-diverting stents ("Pipeline," "Silk" and "FRED" models) without additional coiling were analyzed. All MRI scans included dedicated two-phase ceMRA. Aneurysm occlusion rates, size of the aneurysmal sac and complications were evaluated on MRI and digital subtraction angiography (DSA), where available. The ability of ceMRA to depict aneurysm occlusion and stent patency was graded on a three-point scale.Results: Twenty-five patients with 102 MRI scans were included. The median duration of follow-up was 830 days. Aneurysm occlusion rates were 52% at 3 months (10 of 19 patients), 72% at 6 months (18/25) and 84% overall (21/25). Shrinkage of the aneurysmal sac was found in 19 patients (76%) and in 12 cases to <50% of the original size (48%). CeMRA assessability of aneurysmal occlusion was graded as good in all cases. When compared to DSA (18 cases), ceMRA had a sensitivity of 100% and specificity of 91% regarding aneurysm remnant detection. Assessability of the stent lumen varied and was limited in most cases.Conclusions: Flow-diverter treatment achieves high occlusion rates and can cause major aneurysm shrinkage. CeMRA is highly valuable regarding imaging of the aneurysmal sac. There are limitations regarding the assessability of the stent lumen on ceMRA.Level Of Evidence: Level 4, Case Series. [ABSTRACT FROM AUTHOR]

Background and Purpose: The experience of flow diverters (FDs) in treating large vertebral artery-dissecting aneurysms (VADAs) is still limited. This study was conducted to present our long-term outcome of VADAs treated with a Tubridge flow diverter (TFD), a new device developed in China. Materials and Methods: The clinical and angiographic data of six patients harboring large VADAs and treated with TFDs were prospectively collected and analyzed. Results: A total of nine TFDs were successfully implanted in six patients. Angiographic follow-up images were available for all patients at a median of 26.0 (18.5, 37.5) months after treatment. Five of the six VADAs were completely occluded, and the last was improved (near complete occlusion). In-stent stenosis was detected in one case and was handled appropriately by angioplasty and stenting. All covered branches and parent arteries remained patent. There were no complications or new neurological deficits observed in any of the patients. At the latest clinical follow-up (36.5 (26.0, 44.5) months), all patients achieved 0 in the modified Rankin scale score. Conclusions: Our preliminary experience suggests that the Tubridge flow diverter might be an alternative treatment for large and recurrent dissecting aneurysms derived from the vertebral artery. [ABSTRACT FROM AUTHOR]