Flow Diverter Stent Placement Research Articles

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

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. 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. 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.

Bilateral glaucoma attack after flow-diverting stent placement in the left inner catorid artery in the projection of the aneurysm neck: a case report

Bilateral glaucoma attack after flow-diverting stent placement in the left inner catorid artery in the projection of the aneurysm neck: a case report

Periprocedural management of ruptured blister aneurysms treated with pipeline flow diversion.

Blister aneurysms are high-risk intracranial vascular lesions. Definitive treatment of these lesions has been challenging. Severe disability or mortality rates are as high as 55% when these lesions are treated with open surgery. Recent data show that flow diversion is a safe and effective alternative treatment for blister aneurysms. Rerupture of the functionally unsecured lesion remains a concern as flow diversion does not immediately exclude the aneurysm from the circulation. A retrospective review was performed of any patients with ruptured blister aneurysms treated with a pipeline embolization device between 2010 and 2020 at the University of Colorado. In this paper, we present the results of the intensive care management of ruptured intracranial blister aneurysms after flow-diverting stent placement. Despite the need for dual antiplatelet therapy and the delayed occlusion of blister aneurysms treated with flow diversion, we did not find an increase in periprocedural complications.

Comparative evaluation of brain perfusion with ASL and DSC MRI following intracranial vascular flow diverter stent replacement.

The objective of this study was to asses brain perfusion parameters and ischemic changes following treatment of aneurysm with flow diverters with two different perfusion MRI technique (Arterial spin labeling and DSC MRI), and to compare the results and effectiveness of these two methods. The prospective data was collected from patients with aneurysm who treated with flow diverters. MR examinations, including diffusion-weighted imaging (DWI), ASL, and DSC perfusion MRI, were conducted before and after treatment within the first week and at 6 months. Perfusion parameters of territory area and contralateral side were measured and analyzed by statistically. The relationships between ASL and DSC parameters were analyzed by using Sperman's correlation analysis. A total of 14 cases of aneurysms in 11 patients treated successfully with endovascular flow diverter stent placement. Pretreatment and post treatment (within first week and 6 months) MRI images were evaluated. Asymptomatic randomly distributed millimetric restricted diffusion foci were observed in 8 of all patients. There was no statistically difference between pre and post treatment perfusion parameters (p > 0.05). A statistically significant correlation was found between variable ASL CBF, and the variables of DSC CBF and TTP. Notwithstanding the fact that flow diverters change flow dynamics in aneurysm sac, there is no any perfusion abnormality in the territory area. Asymptomatic randomly distributed diffusion restricted foci in the both cerebral hemisphere can be observed. ASL and DSC MRI are effective for evaluation of brain perfusion.

Effect of Platelet Function Testing Guidance on Clinical Outcomes for Patients with Intracranial Aneurysms Undergoing Endovascular Treatment.

Platelet function testing has been proposed to better adjust individualized antiplatelet treatment for patients undergoing endovascular treatment for intracranial aneurysms. Its clinical significance needs to be comprehensively evaluated. Our aim was to evaluate the impact of platelet function testing-guided versus standard antiplatelet treatment in patients receiving endovascular treatment for intracranial aneurysms. PubMed, EMBASE, and the Cochrane Library of clinical trials were searched from inception until March 2023. Eleven studies comprising 6199 patients were included. ORs with 95% CIs were calculated using random effects models. The platelet function testing-guided group was associated with a decreased rate of symptomatic thromboembolic events (OR = 0.57; 95% CI, 0.42-0.76; I2 = 26%). No significant difference was found in asymptomatic thromboembolic events (OR = 1.07; 95% CI, 0.39-2.94; I2 = 48%), hemorrhagic events (OR = 0.71; 95% CI, 0.42-1.19; I2 = 34%), intracranial hemorrhagic events (OR = 0.61; 95% CI, 0.03-10.79; I2 = 62%), morbidity (OR = 0.53; 95% CI, 0.05-5.72; I2 = 86%), and mortality (OR = 1.96; 95% CI, 0.64-5.97; I2 = 0%) between the 2 groups. Subgroup analysis suggested that platelet function testing-guided therapy may contribute to fewer symptomatic thromboembolic events in patients who received stent-assisted coiling (OR = 0.43; 95% CI, 0.18-1.02; I2 = 43%) or a combination of stent-assisted and flow-diverter stent placement (OR = 0.61; 95% CI, 0.36-1.02; I2 = 0%) or who changed from clopidogrel to other thienopyridines (OR = 0.64; 95% CI, 0.40-1.02; I2 = 18%), though the difference did not reach statistical significance. Heterogeneous endovascular treatment methods and adjusted antiplatelet regimens were limitations. Platelet function testing-guided antiplatelet strategy significantly reduced the incidence of symptomatic thromboembolic events without any increase in the hemorrhagic events for patients undergoing endovascular treatment for intracranial aneurysms.

Letter: Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video.

To the Editor: We read with great interest the article “Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video” by Hackett et al.1 The authors present a case of a patient with an arteria lusoria who received effective flow-diverting stent therapy for a large left internal carotid artery (ICA) aneurysm using a large bore guide catheter through right transradial access (TRA). Diagnostic angiography showed that the left ICA could be accessed through the right TRA. A 6F radial sheath was introduced into the right radial artery, and the sheath was then exchanged over a 0.035″ guidewire for an 8F 90-cm guide catheter (Infinity; Stryker Neurovascular). After navigating a 5F 130-cm Simmons catheter into the left common carotid artery through the arteria lusoria, the 8F guide catheter was delivered into the left ICA using the telescoping technique. The large left ICA-ophthalmic artery aneurysm was successfully treated with a pipeline embolization device (Medtronic). The importance of evaluating transradial diagnostic angiography to determine whether a catheter system can safely track into the target supra-aortic vessels is critical for successful transradial neurointervention in patients with arteria lusoria, and we wholeheartedly concur with the authors' conclusion on this point. Cannulation into the supra-aortic vessels through right TRA can be extremely challenging in patients with arteria lusoria because of unfavorable catheter trajectory.2 In addition, the right TRA can cause fatal arteria lusoria dissection.3 Therefore, transfemoral access is frequently employed as first-line access if neurointerventionalists encounter arteria lusoria.2 Previous study reported that left TRA is a technically feasible alternative in neurointerventions for patients with arteria lusoria.4 Nevertheless, a guide catheter may result in a failed TRA that necessitates a crossover to transfemoral access because of a failed cannulation, a kinked catheter, or an unstable system. We have used transradial access as the first-line access for neurointerventions.5-18 The first-line TRA using a 6F preshaped Simmons guiding sheath (outer diameter, 2.70 mm; inner diameter, 0.088″; usable length, 90 cm; 6F Axcelguide Stiff-J; Medikit) offers a large bore working channel and a high procedural success rate without catheter kinking or system instability even in patients with an unfavorable steep supra-aortic take-off.5-7,13 The 6F Simmons guiding sheath is fully engaged into the target common carotid artery with a pull-back maneuver (the pull-back technique) after reforming the Simmons curve within the ascending aorta. The Simmons curve can be reformed by anchoring the 6F Simmons guiding sheath to the descending aorta (the descending aorta anchoring technique) or contralateral subclavian artery (the subclavian artery anchoring technique) through the left TRA. Transradial carotid cannulation with the pull-back technique is technically simple and promising. As a result, left TRA with the 6F Simmons guiding sheath can be a beneficial treatment choice for performing anterior circulation procedures in patients with arteria lusoria. Finally, we would like to express our appreciation to the authors for their interesting article that advances the transradial neurointerventional method.

OUTCOME EVALUATION OF FLOW DIVERTER STENT PLACEMENT IN TREATMENT OF RUPTURED AND UNRUPTURED CEREBRAL ANEURYSMS

Background: Cerebral aneurysms affect about 5% of the population and are associated with high mortality rates and severe complications for families and society. Complex aneurysm types include giant aneurysms, wide - necked aneurysms, blister - like aneurysms, recurrent aneurysms, fusiform aneurysms, and multiple aneurysms, which are difficult to manage with conventional endovascular or surgical methods due to complications such as coil migration and high rates of re - rupture. The development of flow diverter stents has been a breakthrough in recent decades and has been demonstrated to be safe and effective in treating aneurysms. The aim of this study was to evaluate the outcomes of flow diverter stent placement in the treatment of ruptured and unruptured cerebral aneurysms. Methods: This was a descriptive prospective study that followed up on 23 patients diagnosed and treated for cerebral aneurysms with flow - diverter stent intervention at the Stroke Department of Hue Central Hospital from 6/2020 to 6/2022. The follow - up data after 6 months and 12 months were recorded. Results: There were 23 patients (9 males, 14 females) with 28 cerebral aneurysms, with a mean age of 51.7 ± 9.9 years. Aneurysms were predominantly located in the anterior circulation (85.7%) and 14.3% in the posterior circulation. The most common aneurysm type was fusiform (75%), followed by dissecting (17.9%) and blister - like (7.1%). Most aneurysms had wide necks, with a neck - to - dome ratio < 1.5, accounting for 82.1%. Flow diverter stent placement was successfully performed in 91.3% of patients, with 27 stents used. Stents were properly positioned, well - expanded in 88.9%. The complication rate after intervention was 4.3%. Complete aneurysm occlusion rates at 6 to 12 months were 92.9% and 96.4%, respectively. The rate of mild in - stent stenosis without clinical symptoms was 4.3%. The good outcome rate (mRS 0 - 2) was 91.3%. Conclusion: Flow diverter stent is effective and safe with high rate of successful and low procedural complications in the treatment of complex cerebral aneurysms.

Flow Diversion for Acutely Ruptured Intracranial Aneurysms Treatment: A Retrospective Study and Literature Review

ObjectiveFlow diversion is becoming an increasingly established practice for the treatment of acutely ruptured intracranial aneurysms. In this study the authors present a literature review and meta-analysis, adding a retrospective review of institutional registry on emergency treatment of aRIA with flow diverter stent. Materials and methodsA systematic search of PubMed, SCOPUS, Ovid MEDLINE, and Ovid EMBASE was performed on April 20th, 2021, extrapolating 35 articles. R language ‘meta’ and ‘metafor’ packages were used for data pooling. The DerSimonian-Laird model was used to calculate the pooled effect. The I2 value and Q statistic evaluated study heterogeneity. Additionally, the authors retrospectively reviewed their institutional database for the treatment and outcomes of all patients with acutely ruptured intracranial aneurysms treated with flow diverter stent placement from May 2010 to November 2020 was performed. ResultsFrom the systematic literature review and meta-analysis, the pooled proportion of complete aneurysm occlusion was 78%, with a pooled rate of 79%, 71%, 80%, and 50% for dissecting, saccular, fusiform, and mycotic aneurysms, respectively. The pooled proportion of aneurysm rebleeding and intrastent stenosis was 12% and 15% respectively, for a total of 27% rate. The analysis of authors retrospective register showed an overall mortality rate of 16.7% (3/18), with a low but not negligible postprocedural rebleeding and intrastent thrombosis rates (5.6% and 11.1% respectively). ConclusionAlthough increasingly utilized in the management of selected patients with acutely ruptured intracranial aneurysms, flow diversion for acutely ruptured intracranial aneurysms treatment presents rebleeding and intrastent stenosis rates not negligible.

Parent Artery Straightening after Flow-Diverter Stenting Improves the Odds of Aneurysm Occlusion.

Intracranial stents for the treatment of aneurysms can be responsible for parent artery straightening, a phenomenon with potential consequences for aneurysmal occlusion. We aimed to evaluate parent artery straightening following flow-diverter stent placement in patients with intracranial aneurysms and explored the association between parent artery straightening and subsequent aneurysm occlusion. All patients treated with flow-diverter stents for anterior circulation aneurysms located downstream from the carotid siphon between January 2009 and January 2018 were screened for inclusion. Parent artery straightening was defined as the difference (α-β) in the parent artery angle at the neck level before (α angle) and after flow-diverter stent deployment (β angle). We analyzed the procedural and imaging factors associated with parent artery straightening and the associations between parent artery straightening and aneurysmal occlusion. Ninety-five patients met the inclusion criteria (n = 64/95 women, 67.4%; mean age, 54.1 [SD, 11.2] years) with 97 flow-diverter stents deployed for 99 aneurysms. Aneurysms were predominantly located at the MCA bifurcation (n = 44/95, 44.4%). Parent artery straightening was found to be more pronounced in patients treated with cobalt chromium stents than with nitinol stents (P = .02). In multivariate analysis, parent artery straightening (P = .04) was independently associated with aneurysm occlusion after flow-diverter stent deployment. The use of flow-diverter stents for distal aneurysms induces a measurable parent artery straightening, which is associated with higher occlusion rates. Parent artery straightening, in our sample, appeared to be more prominent with cobalt chromium stents than with nitinol stents. This work highlights the necessary trade-off between navigability and parent artery straightening and may help tailor the selection of flow-diverter stents to aneurysms and parent artery characteristics.

Prediction of Cerebral Aneurysm Hemodynamics With Porous-Medium Models of Flow-Diverting Stents via Deep Learning

The interventional treatment of cerebral aneurysm requires hemodynamics to provide proper guidance. Computational fluid dynamics (CFD) is gradually used in calculating cerebral aneurysm hemodynamics before and after flow-diverting (FD) stent placement. However, the complex operation (such as the construction and placement simulation of fully resolved or porous-medium FD stent) and high computational cost of CFD hinder its application. To solve these problems, we applied aneurysm hemodynamics point cloud data sets and a deep learning network with double input and sampling channels. The flexible point cloud format can represent the geometry and flow distribution of different aneurysms before and after FD stent (represented by porous medium layer) placement with high resolution. The proposed network can directly analyze the relationship between aneurysm geometry and internal hemodynamics, to further realize the flow field prediction and avoid the complex operation of CFD. Statistical analysis shows that the prediction results of hemodynamics by our deep learning method are consistent with the CFD method (error function <13%), but the calculation time is significantly reduced 1,800 times. This study develops a novel deep learning method that can accurately predict the hemodynamics of different cerebral aneurysms before and after FD stent placement with low computational cost and simple operation processes.

CFD Study on the Efficacy of Flow Diverter Stent Placement for Cerebral Aneurysms

The effect of flow diverter (FD) stent placement as a cerebral aneurysm treatment on hemodynamics was systematically investigated via numerical simulation. The aneurysm diameter was set to 8 mm and 12 mm, with an aspect ratio (AR) of 1.2 and 1.9, respectively. The curvature of the parent artery was also varied for the following three types: straight, inside, and outside. The blockage ratio of the FD stent was set to 31 %. The results reveal that, regardless of artery shape, the FD stent drastically modifies the flow in the aneurysm, including changing the flow direction in the systolic phase. In most cases, the flow rate into the aneurysm is significantly reduced by the stent; however, in the case of a straight artery, the flow rate is increased for the aneurysm model with AR = 1.9. The oscillatory shear index (OSI) generally increases owing to FD stent placement while the wall shear stress is substantially decreased. In particular, a high OSI area is widely distributed in the large aneurysm sac (AR = 1.9) for straight and internal artery cases. Although idealized aneurysm models are employed in the present study and further parametric studies are required, particularly with respect to stent configuration, these facts may explain the unexpected outcome in some (but not all) large aneurysm cases.

A Posterior Communicating Segment Aneurysm of the Supraclinoid Internal Carotid Artery Treated with an Extracranial to Intracranial Bypass and Trapping.

Surgical treatment of giant aneurysms often poses significant challenges. Endovascular techniques have evolved exponentially over the last decades, and most of these complex aneurysms can be treated with flow-diverting techniques; however, successful obliteration of all giant aneurysms is not always possible with endovascular flow-diverting techniques. Although the need for microsurgical intervention has undoubtedly diminished, a versatile-thinking surgeon should keep in mind that obliteration of these aneurysms combined with revascularizing the distal circulation via extracranial–intracranial bypass techniques can provide a potentially life-long durable solution. The key to curing these pathologies is to utilize interdisciplinary decision making with a robust knowledge of the pros and cons of different treatment approaches. Herein, we present a case of a giant posterior communicating segment aneurysm of the left supraclinoid internal carotid artery (ICA), which was treated by obliteration ( Fig. 1 ). Extradural anterior clinoidectomy was used to provide exposure of the supraclinoidal ICA proximal to the aneurysm, and revascularization of the distal circulation was achieved with a common carotid artery to M2-superior trunk bypass using a radial artery interposition graft ( Fig. 2 ). The patient was a 62-year-old female who presented with vision loss in her left eye but was otherwise neurologically intact. She had a history of two unsuccessful flow-diverting stent placement attempts 2 months prior to this surgery. Postoperatively, the patient woke up without any deficits, with her left eye vision partially recovered and ultimately returning to normal at 1-year follow-up. Computed tomography (CT) angiography at a 1-year follow-up showed complete obliteration of the aneurysm and successful revascularization of the distal circulation. The link to the video can be found at: https://youtu.be/DsIuIJJj1l4 .

Dual-center study comparing transradial and transfemoral approaches for flow diversion treatment of intracranial aneurysms

BACKGROUND:The transfemoral approach (TFA) has been the traditional approach for neurointerventional cases. While the TFA allows for triaxial support in flow diverting stent cases, it is associated with access site complications. Recently, the transradial approach (TRA) has emerged as a safer alternative to the TFA. To the best of our knowledge, there have only been single-center studies comparing outcomes in flow diverter cases for these approaches. We demonstrate the safety and feasibility of the TRA for placement of flow diverting stents in the treatment of unruptured intracranial aneurysms at two high-volume centers.MATERIALS AND METHODS:We performed a retrospective review of prospectively collected institutional databases at two high-volume neuroendovascular centers. Cases from 2016 to 2018 of unruptured intracranial aneurysms treated by flow diverting stenting accessed through either the TRA or the TFA were compared. Patient demographics, procedural and radiographic metrics including location and size of the aneurysm, size, and length of the flow diverter implant, and fluoroscopic time were recorded. Puncture site complications and length of hospital stay were also included in the data analysis.RESULTS:There were three out of 29 TRA cases which were converted to the TFA. None of the TRA patients experienced site complications, whereas three TFA patients experienced site complications. While TRA and TFA patients did not differ significantly in their exposure to radiation, TRA patients experienced shorter hospital stays.CONCLUSIONS:While long-term studies are still lacking regarding this approach, we demonstrate that the TRA is a safe and feasible approach for flow diverter stent placement.

Lower Complication Rates Associated with Transradial vs. Transfemoral Flow Diverting Stent Placement

Lower Complication Rates Associated with Transradial vs. Transfemoral Flow Diverting Stent Placement

Unruptured Intracranial Aneurysms in Elderly Patients: Results of Surgical and Endovascular Treatment

Background: Management of unruptured intracranial aneurysms (UIA) in elderly patients is controversial, taking into consideration their limited life-expectancy and existing comorbidities. With advances in endovascular techniques, we decided to evaluate treatment results in this population and to assess results in surgically and endovascularly treated cases. Methods: Thirty six elderly patients, aged ≥ 70, with the total of 39 aneurysms, were treated. The possibility of endovascular treatment was considered as the first option and surgical treatment as the second method of intervention. Results: No patient died and no patient became bedridden after the procedures. In surgical group (14 UIA), deterioration was observed in five cases at the time of discharge, but persisted in only two cases at follow-up. In endovascular group (25 UIA), deterioration was observed in one case at the time of discharge and persisted at follow-up. Endovascular techniques included coils placement alone in nine (36%) procedures, coiling with stent placement in five (20%) procedures and stent placement alone in eleven (44%) procedures. Follow-up DSA revealed no treatment effect in three patients after stent placement alone (12% of endovascularly treated aneurysms). Of these, two patients were successfully retreated with second flow-diverting stent placement and one patient refused retreatment. Conclusion: Treatment of elderly patients with UIA is relatively safe and effective. Worse short-term and long-term outcomes were observed among the operated compared to embolized patients. In patients treated with stent placement alone, treatment failure and the need for the next stage of embolization in some cases should be taken into account.

Lower complication rates associated with transradial versus transfemoral flow diverting stent placement

BackgroundCurrently, there are no large-scale studies in the neurointerventional literature comparing safety between transradial (TRA) and transfemoral (TFA) approaches for flow diversion procedures. This study aims to assess complication rates...

Factors influencing blood flow resistance from a large internal carotid artery aneurysm revealed by a computational fluid dynamics model.

ABSTRACTHyperperfusion syndrome occurs after treatment of a large or giant cerebral aneurysm. Recently, flow-diverter stent placement has emerged as an effective treatment method for a large cerebral aneurysm, but postoperative ipsilateral delayed intraparenchymal hemorrhage occurs in a minority of cases. The mechanism underlying delayed intraparenchymal hemorrhage is not established, but one possibility is hyperperfusion syndrome. The incidence of delayed intraparenchymal hemorrhage appears to be higher for giant aneurysms; hence, we speculated that large/giant aneurysms may create flow resistance, and mitigation by flow-diverter stent deployment leads to hyperperfusion syndrome and delayed intraparenchymal hemorrhage. The purpose of this study was to identify aneurysm characteristics promoting flow resistance by the analysis of pressure loss in an internal carotid artery paraclinoid aneurysm model using computational fluid dynamics. A virtual U-shaped model of the internal carotid artery siphon portion was created with a spherical aneurysm of various angles, body diameters, and neck diameters. Visualization of streamlines, were calculated of pressure loss between proximal and distal sides of the aneurysm, and vorticity within the aneurysm were calculated. The pressure loss and vorticity demonstrated similar changes according to angle, peaking at 60°. In contrast, aneurysm diameter had little influence on pressure loss. Larger neck width, however, increases pressure loss. Our model predicts that aneurysm location and neck diameter can increase the flow resistance from a large internal carotid artery aneurysm. Patients with large aneurysm angles and neck diameters may be at increased risk of hyperperfusion syndrome and ensuing delayed intraparenchymal hemorrhage following flow-diverter stent treatment.

Impact of flow diverter stent placement on hemodynamics in the cerebral aneurysm

Impact of flow diverter stent placement on hemodynamics in the cerebral aneurysm

フローダイバータ型ステント留置下での脳動脈瘤内流れの数値シミュレーション

フローダイバータ型ステント留置下での脳動脈瘤内流れの数値シミュレーション

Four-dimensional MRI flow examinations in cerebral and extracerebral vessels - ready for clinical routine?

To evaluate the feasibility of 4-dimensional (4D) flow MRI for the clinical assessment of cerebral and extracerebral vascular hemodynamics in patients with neurovascular disease. 4D flow MRI has been applied in multiple studies to qualitatively and quantitatively study intracranial aneurysm blood flow for potential risk stratification and to assess treatment efficacy of various neurovascular lesions, including intraaneurysmal and parent artery blood flow after flow diverter stent placement and staged embolizations of arteriovenous malformations and vein of Galen aneurysmal malformations. Recently, the technique has been utilized to characterize age-related changes of normal cerebral hemodynamics in healthy individuals over a broad age range. 4D flow MRI is a useful tool for the noninvasive, volumetric and quantitative hemodynamic assessment of neurovascular disease without the need for gadolinium contrast agents. Further improvements are warranted to overcome technical limitations before broader clinical implementation. Current developments, such as advanced acceleration techniques (parallel imaging and compressed sensing) for faster data acquisition, dual or multiple velocity encoding strategies for more accurate arterial and venous flow quantification, ultrahigh-field strengths to achieve higher spatial resolution and streamlined postprocessing workflow for more efficient and standardized flow analysis, are promising advancements in 4D flow MRI.