Flow Diversion Research Articles

Clipping, Aneurysmotomy, and Thrombectomy of an Enlarged Thrombosed Giant Posterior Cerebral Artery Aneurysm After Flow Diverter Treatment: 2-Dimensional Operative Video.

Clipping, Aneurysmotomy, and Thrombectomy of an Enlarged Thrombosed Giant Posterior Cerebral Artery Aneurysm After Flow Diverter Treatment: 2-Dimensional Operative Video.

Computer Aided Intracranial Aneurysm Treatment Based on 2D/3D Mapping, Virtual Deployment and Online Distal Marker Detection.

To introduce a computational tool for peri-interventional intracranial aneurysm treatment guidance that maps preoperative planning information from simulation onto real-time X-Ray imaging. Preoperatively, multiple flow diverter (FD) devices are simulated based on the 3D mesh of the vessel to treat, to choose the optimal size and location. In the peri-operative stage, this 3D information is aligned and mapped to the continuous 2D-X-Ray scan feed from the operating room. The current flow diverter position in the 3D model is estimated by automatically detecting the distal FD marker locations and mapping them to the treated vessel. This allows to visually assess the possible outcome of releasing the device at the current position, and compare it with the one chosen pre-operatively. The full pipeline was validated using retrospectively collected biplane images from four different patients (5 3D-DSA datasets in total). The distal FD marker detector obtained an average F1-score of 0.67 ( ) in 412 2D-X-Ray scans. After aligning 3D-DSA + 2D-X-Ray datasets, the average difference between simulated and deployed positions was 0.832 mm ( mm). Finally, we qualitatively show that the proposed approach is able to display the current location of the FD compared to their pre-operatively planned position. The proposed method allows to support the FD deployment procedure by merging and presenting preoperative simulation information to the interventionists, aiding them to make more accurate and less risky decisions.

Knowledge domain and emerging trends in the rupture risk of intracranial aneurysms research from 2004 to 2023.

Intracranial aneurysms (IAs) pose significant health risks, attributable to their potential for sudden rupture, which can result in severe outcomes such as stroke and death. Despite extensive research, the variability of aneurysm behavior, with some remaining stable for years while others rupture unexpectedly, remains poorly understood. To employ bibliometric analysis to map the research landscape concerning risk factors associated with IAs rupture. A systematic literature review of publications from 2004 to 2023 was conducted, analyzing 3804 documents from the Web of Science Core Collection database, with a focus on full-text articles and reviews in English. The analysis encompassed citation and co-citation networks, keyword bursts, and temporal trends to delineate the evolution of research themes and collaboration patterns. Advanced software tools, CiteSpace and VOSviewer, were utilized for comprehensive data visualization and trend analysis. Analysis uncovered a total of 3804 publications on IA rupture risk factors between 2006 and 2023. Research interest surged after 2013, peaking in 2023. The United States led with 28.97% of publications, garnering 37706 citations. Notable United States-China collaborations were observed. Capital Medical University produced 184 publications, while Utrecht University boasted a citation average of 69.62 per publication. "World Neurosurgery" published the most papers, contrasting with "Stroke", the most cited journal. The PHASES score from "Lancet Neurology" emerged as a vital rupture risk prediction tool. Early research favored endovascular therapy, transitioning to magnetic resonance imaging and flow diverters. "Subarachnoid hemorrhage" stood out as a recurrent keyword. This study assesses global IA research trends and highlights crucial gaps, guiding future investigations to improve preventive and therapeutic approaches.

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

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

Flow diversion for unruptured MCA bifurcation aneurysms: comparison of p64 classic, p64 MW HPC, and p48 MW HPC flow diverter stents.

MCA bifurcation aneurysms pose treatment challenges because of the complex hemodynamics at the bifurcation and the risk of rupture. FDS implantation has been controversial and there are only limited reports. Therefore, the aim of this study was to assess the efficacy and safety of this treatment strategy using p64 MW HPC and p48 MW HPC FDSs for MCA bifurcation aneurysms, compared with the p64 classic FDS. We retrospectively analyzed our institutional database and identified all patients with saccular, non-ruptured MCA bifurcation aneurysms treated with p64 MW HPC, p48 MW HPC, or p64 classic FDS implantation alone. Aneurysms with implantation of additional devices in the same session, previous treatments, and acutely ruptured and fusiform aneurysms were excluded. A total of 79 aneurysms met the inclusion criteria: 23 receiving a p64 MW HPC, 34 receiving a p48 MW HPC, and 22 receiving a p64 classic FDS. The occlusion rate was highest for the p48 MW HPC 2 mm FDS, at 88.9% at FU2, compared with 72.2% for the p64 MW HPC and 70.6% for the p64 classic. The time to aneurysm occlusion was shortest with the p64 MW HPC, at 178.31 days. The highest retreatment rate was observed with the p48 MW HPC 3 mm. Treatment of MCA bifurcation aneurysms with a p48 MW HPC 2 mm or p64 MW HPC FDS is a safe and reliable strategy achieving high aneurysm occlusion rates - attributable to their lower porosity in relation to the parent vessel diameter as compared to the p48 MW HPC 3 mm FDS-, with reasonable morbidity and mortality.

A multi‐site and hypothesis‐driven approach to identify controls on the bedload transport regime of an anthropised gravel‐bed river

AbstractUnderstanding the effects of human disturbance on the bedload transport regime of anthropised rivers is a topic of growing importance, as such information is of interest for adequate river diagnosis, correct implementation of restoration measures and appropriate design of post‐action monitoring programs. However, such assessments are complex, especially in sites where multiple factors simultaneously influence the bedload transport regime, so that it is difficult to establish simple causal relationships between human disturbances and changes in the sediment transport regime, notably on bedload. To overcome this, there is a need for rigorous hypothesis‐driven approaches to assess the isolated effects of each driver. With this in mind, we have characterised the dynamics of bedload transport in the Upper Garonne (Central Pyrenees, Spain‐France), a river impacted by sediment retention, flow diversion and mining that influence its morphological conditions and transport regime. We assessed the effects of (1) surface grain size distribution, (2) river morphology, (3) sediment supply and (4) flow diversion on the bedload transport regime. Four sites with different degrees of river anthropisation were selected. After defining hypotheses on the most likely bedload transport conditions for each site, we proposed a set of discriminating criteria to test these hypotheses, based on temporal within‐site and spatial between‐site comparisons of coarse particle tracking measurements over four years. The results of this research showed that the hydrosedimentary regime of the Garonne is controlled by a complex combination of drivers such as valley physiography, which exerts a first‐order control on differences in reach‐scale bedforms and bedload dynamics; and human disturbances which contribute to a reduction in sediment supply through changes in land cover and hydropower dams, or to changes in hydrology (i.e., flow competence) due to water diversion and abstraction.

Repeated apheresis donations cause important iron deficiency in male Japanese donors.

In Japan, apheresis donation of plasma is allowed to a maximum of 24 times a year, and plateletpheresis are counted as two plasmapheresis donations. Diversion of the initial blood flow is conducted for all donations, and additionally, blood remaining in apheresis machine circuit is lost. Here, we aimed to investigate on the health impact of frequent apheresis donations, as measured by the serum ferritin (sFer). A total of 538 male apheresis donors and 538 age-matched whole blood (WB) donors, who gave informed consent to join the study, were enrolled. sFer were compared, according to age. Another group of 19 apheresis donors were followed during four consecutive donations. About half (48%) of repeat male apheresis donors had iron deficiency (sFer < 26 ng/mL), compared with lower rates (13.9%) among male WB donors. It was evident in all age groups, except for teenagers, possibly because of the lower number of donations. Follow-up of the 19 donors for 4 months revealed a progressive decrease in sFer. Blood remaining in the apheresis machine circuit and diversion of the initial blood flow have been implicated in iron deficiency for many years. Taking the present results, the manufacturer of apheresis equipment was requested to improve it to allow rinseback of the remaining blood, which was achieved only for plateletpheresis. Until further improvement, plasmapheresis frequency was reduced to 12 times a year. Additional measures, such as oral supplementation of iron, need to be considered.

Clopidogrel Hyperresponsiveness and Hemorrhagic Complications Using On-Label Clopidogrel Dosing after Pipeline Embolization.

Introduction: Clopidogrel hyperresponsiveness is a timely topic, with wide ranging reports of hemorrhagic complications, using various clopidogrel dosing strategies following neuroendovascular procedures. This study serves to investigate hemorrhagic complications using standard clopidogrel doses and timing of these complications in relation to the procedure. Materials and Methods: Retrospective cohort of consecutive adult patients undergoing flow diversion with Pipeline Embolization Device (PED) at an academic medical center, receiving on-label clopidogrel doses. Patients with clopidogrel hyperresponsiveness (VerifyNowTM P2Y12 reaction unit (PRU) ≤ 70) were compared to those who were normoresponsive. The primary outcome is the rate of hemorrhagic complications between groups. Results: Of 148 included patients, 54 (36.5%) were identified as clopidogrel hyperresponsive (PRU ≤ 70) and 94 (63.5%) as clopidogrel normoresponsive (PRU 71 - 194). There were no hemorrhagic complications observed in patients who were clopidogrel hyperresponsive, with 5 occurring in patients who were normoresponsive (P = 0.09). Three (60%) of the hemorrhages were intracranial with most occurring intra-procedure or within the first week of the procedure. Age > 60years was the only candidate predictor for hemorrhagic complications (P = 0.004). Conclusion: Our findings are contradictory, with lower hemorrhagic complications in clopidogrel hyperresponders than prior literature, and most occurring intra-op or in the immediate acute post-op phase.

Initial Experience with the Derivo 2Heal Flow Diverter under Standard or Reduced-Dose Single Antiplatelet Therapy.

Flow diverters with surface modifications or coatings have been recently introduced to clinical practice with the expectation that they can reduce the rate of thromboembolic complications and residual aneurysms. The purpose of this study is to evaluate the utility of the Derivo 2Heal (D2H) device, a new fibrin and heparin-coated flow diverter. Patients treated by a single operator by using the D2H were retrospectively evaluated for demographic data, aneurysm characteristics, procedural variables, and follow-up data. All patients were treated by using a single D2H, monitored by platelet function testing and kept under single antiplatelet therapy with regular or half-dose clopidogrel or prasugrel after the procedure. Twenty patients with 26 aneurysms were treated. Three presented acutely with subarachnoid hemorrhage. Adjunctive devices were used in 6 patients. There were no technical failures and 2 periprocedural self-limited nonthrombotic minor adverse events. During follow-up, 1 of the acutely ruptured aneurysms reruptured, and 1 patient had a visual TIA. All patients were doing well clinically (19 with mRS of 0 and 1 with 1) at the last follow-up after discharge. The rates of total occlusion on very early angiographic (MRA/CTA or DSA, mean: 2.4 months), DSA (mean: 5.8 months), and midterm angiographic (mean: 14.5 months) follow-up for all versus uncoiled aneurysms were 68% versus 70%, 77.8% versus 90.0%, and 91.7% versus 90.1%, respectively. The absence of permanent neurologic deficits in the periprocedural period and favorable occlusion rates in this preliminary study suggest that the novel coating comprising fibrin and heparin may have the potential to increase the safety and efficacy of flow diversion and needs to be further studied by comparing the D2H device with its bare counterpart and other coated or surface-modified flow diverters.

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

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

Contralateral approach to giant ruptured and unruptured ophthalmic artery aneurysms: patient series.

Giant ophthalmic artery (OphA) aneurysms remain surgically challenging despite the progress in endovascular treatments. This study describes the contralateral interoptic corridor in select patients based on imaging criteria suitable for clipping. The aim of this study was to show that despite the growing use of novel endovascular techniques, such as coil embolization and flow diversion, for the treatment of OphA aneurysms, microsurgical clipping may still be preferred for giant ones under certain conditions. The authors retrospectively reviewed the records of the microsurgical treatment of unruptured and ruptured giant OphA aneurysms at the University Hospital Center "Mother Teresa," Tirana, from 2007 to 2016. Four patients were selected for microsurgery and the contralateral approach using ophthalmic evaluations and coronal imaging on computed tomography, magnetic resonance imaging, and digital subtraction angiography that demonstrated aneurysms with a small neck and an orientation between 11 and 13 on the coronal clock face. A prefixed chiasm was a contraindication to this approach. Giant OphA aneurysms can be safely clipped through a contralateral interoptic corridor without creating new visual deficits or a residual aneurysm. https://thejns.org/doi/10.3171/CASE2473.

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

BackgroundThis study reports a multicenter experience of using hydrophilic polymer-coated (HPC) flow diverters with prasugrel single antiplatelet therapy to treat ruptured aneurysms with subarachnoid hemorrhage (SAH).MethodsPatients treated for intracranial aneurysms...

A Novel Scoring System Predicting Aneurysm Incomplete Occlusion After Flow Diversion: A 10-Year Experience

Factors impacting the rate of aneurysm occlusion after flow diversion (FD) have been well described in the literature. In this article, we sought to evaluate those variables to develop and validate a scoring system predicting aneurysm incomplete occlusion after FD. Retrospective review of patients with intracranial aneurysms treated with FD at a single institution between March 2013 and March 2023. Multivariable logistic regression model was developed using factors associated with aneurysm incomplete occlusion. The ABC scoring system consisted of: Age (<60years old: 0, 60-69years: 1, 70-79: 2, and ≥80: 3), Branch coming out of the aneurysm dome/neck (yes: 2, no: 0), and Cigarette smoking history (never smoker: 1, current or past smoker: 0). The scoring system performance was evaluated with receiver operating characteristic curve and calculating the area under the curve. A total of 449 patients with 563 aneurysms treated in 482 procedures were evaluated. Most cases were females (81.7%) with a median age of 59 years old. At a median follow-up of 13.2months, 84.0% of aneurysms were completely or near-complete occluded. The scoring system had an area under the curve of 0.71. A value≥2, reached a sensitivity of 74.4%, a specificity of 60.9%, a likelihood ratio+ of 1.90, and proved to be reliable in predicting the risk of incomplete occlusion (odds ratio=4.53; 95% confidence interval: 2.73-7.54; P<0.001). The proposed ABC scoring system can be used to evaluate the risk of aneurysm incomplete occlusion after treatment with FD, identifying patients who would benefit from adjunctive coiling or alternative treatment modalities.

Anterior choroidal artery aneurysms: a systematic review and meta-analysis of outcomes and ischemic complications following surgical and endovascular treatment.

Anterior choroidal artery (AChA) aneurysms account for 2%-5% of all intracranial aneurysms. Treatment considerations include microsurgical clipping, flow diversion, or coiling with or without adjunctive devices. AChA aneurysms pose challenges in treatment due to the origination of the aneurysm from the origin or proximal segment of the AChA. The AChA is particularly susceptible to vasospasm and occlusion during treatment with devastating neurological deficits, including hemiparesis, hemianesthesia, lethargy, neglect, and hemianopia. In this study, the authors performed a meta-analysis to quantify the outcomes and complication rates across treatment modalities for AChA aneurysms and to identify risk factors reported in the literature. The authors performed a systematic review of AChA aneurysms treated with surgical clipping, endovascular coiling, or flow diversion and reported in the PubMed, Embase, Scopus, and Cochrane search databases. Single-arm meta-analyses of the selected outcomes were performed in RStudio. Literature review yielded 25 studies that met the inclusion criteria. In total, 1627 patients were included in the analysis, with 554 males, 1009 females, and 64 unspecified. The rate of any complication in the full cohort was 11.6%, with a rate of ischemic complications of 5.5% and a favorable recovery rate of 90.3% of all patients treated. In total, 1064 patients underwent surgical clipping, 443 were treated with coiling, and 120 patients with flow diversion. In clipped patients, the rate of total surgical complications was 17.6%, with an ischemic complication rate of 9.4%. The rate of good functional recovery, defined on the basis of a Glasgow Outcome Scale score of 4-5 or modified Rankin Scale score of 0-2, was 88.0%, and complete obliteration was achieved in 84.5% of surgically clipped aneurysms. The complication rate in coiled patients was 10.3%, with an ischemic complication rate of 3.0%. Good functional recovery was achieved in 88.6% of coiled patients and complete aneurysm obliteration in 74.1%. Flow diversion resulted in a complication rate of 1.3%, with 0.7% rate of ischemic complications. Good functional recovery was achieved in 98.4% of patients and complete aneurysm obliteration in 79.0% in the flow diversion group. Aneurysm morphological features that impacted the complication rate were also identified to augment quantitative data and to help guide treatment selection for AChA aneurysms. Flow diversion showed significantly lower total and ischemic complications and improved outcomes compared to clipping and coiling. There may be differences in outcomes between treatment types, especially when considering the varied patient presentations that guide treatment selection.

Endovascular treatment of unruptured intracranial aneurysms: Rate of thromboembolic events depicted by diffusion-weighted imaging in relation to different techniques

BackgroundThe rate of thromboembolic events (TEEs) associated with endovascular treatment (EVT) of intracranial aneurysms is not reported uniformly in the literature due to the various ways that are used to...

Timing, type, and impact of thromboembolic events caused by flow diversion: a 10-year experience.

Thromboembolic (TE) events are among the most feared complications after flow diversion (FD) and have been reported to occur even with adequate dual antiplatelet therapy. Herein, the authors characterize thrombotic and embolic events that developed after FD, focusing on the morbidity of each of these events and the predisposing factors associated with their development. A retrospective analysis of aneurysms treated with FD at a single institution in the US between 2013 and 2023 was performed. The authors documented the emergence of intraprocedural and postoperative TE events. A survival analysis and a Cox regression model was conducted to identify predictors associated with these events. The authors included 651 procedures performed in 591 patients to treat 746 aneurysms. TE events occurred in 38 of the procedures performed (5.8%), causing permanent deficit in 20 patients and death in 4 patients. Eleven cases presented with acute stent thrombosis, 11 with large-vessel occlusion, and 9 with perforator strokes. At a median follow-up of 9.5 months, 73.0% of patients with an ischemic event had a modified Rankin Scale score ≤ 2. Three of the deaths were secondary to occlusion at the basilar trunk and vertebral artery. In patients with TE events in the anterior circulation, 7 of 11 patients with middle cerebral artery occlusion and 9 of 12 patients with internal carotid artery occlusion achieved independence. Time-to-event Cox regression analysis demonstrated that TE events were more frequent in patients exhibiting aspirin resistance (hazard ratio 2.66; 95% CI 1.10-6.70). TE events after FD result from multiple factors, including age, aneurysm characteristics, aneurysm location, antiplatelet resistance, and procedural factors. In our cohort, we found the highest morbidity for patients with TE events presenting with large-vessel occlusion at the middle cerebral artery, and vertebrobasilar system.

Endovascular Management of Basilar Artery Aneurysms: A Consecutive Series of 124 Patients

There is currently no established criterion for determining when interventional treatment is necessary and what strategy is appropriate for basilar artery (BA) aneurysms. Through this study, we aimed to propose an algorithm that can effectively determine the optimal endovascular treatment (EVT) option for BA aneurysms. We enrolled patients with BA aneurysms from June 2016 to December 2022 and performed procedures based on the algorithm. The analysis included demographic, clinical, and aneurysmal characteristics, procedural details, complications, angiographic outcomes, and clinical outcomes. This study included 124 patients (mean age 55.0 years) with a BA aneurysm who underwent EVT. Of these, 21 aneurysms were treated in the setting of subarachnoid hemorrhage (SAH). The majority of aneurysms were located at the basilar apex (74), followed by the basilar trunk (30) and vertebrobasilar junction (20). Coiling was used in 18.5% of cases, while stent-assisted coiling embolization was chosen for 58.9%. Overlapping stents were used in 12.9%, flow diverter (FD) implantation in 3.2%, Y/T stent techniques in 4.8%, and stent adjunctive coiling with unilateral vertebral artery (VA) occlusion in only 1.6%. Procedure-related complications occurred in 15 patients (12.1%). Patients had a modified Rankin Scale(mRS) score of 0.74±1.62; 98 (86.7%) had good prognosis with mRS scores ranging from 0 to 2 at the last follow-up. DSA was performed on 105 (84.7%) patients revealing that 101 (81.5%) achieved complete or near-complete occlusion. The endovascular treatment criteria for BA aneurysms depended on the multi-characteristics was safe and effective. However, further evidence is needed from large cohort studies.

Efficacy of high-resolution vessel wall MRI in the postoperative assessment of intracranial aneurysms following flow diversion treatment.

Certain patients must undergo frequent postoperative digital subtraction angiography (DSA) after flow diversion (FD) therapy. No imaging modality with an efficacy comparable to that of DSA has been established. This study was conducted to determine the efficacy of contrast-enhanced delay alternating with nutation for tailored excitation (DANTE) T1-sampling perfection with application-optimized contrasts by using different flip angle evolution (SPACE), a high-resolution vessel wall magnetic resonance imaging technique for evaluating the occlusion status of intracranial aneurysms after FD treatment, with DSA serving as the reference standard. This retrospective study included 23 patients with 26 aneurysms who had undergone FD treatment between April 2016 and May 2022. Contrast-enhanced DANTE T1-SPACE and DSA were performed as postoperative follow-up imaging studies at 45 time points, both in the same period. The agreement rates for aneurysm occlusion status in the 45 imaging studies were examined. Contrast-enhanced DANTE T1-SPACE had a sensitivity and specificity of 96.3% (26/27) and 83.3% (15/18), respectively, for detecting aneurysm remnants. Overall, 91.1% (41/45) of findings detected on contrast-enhanced DANTE T1-SPACE were consistent with those on DSA. The findings detected on contrast-enhanced DANTE T1-SPACE were completely consistent with those of intraaneurysmal residual blood flow identified on DSA or high-resolution cone-beam computed tomography images in 74.1% (20/27) of the examinations that showed incomplete occlusion on DSA. Furthermore, parent artery status after FD treatment on contrast-enhanced DANTE T1-SPACE was consistent with that observed on DSA in 97.8% (44/45) of examinations. Contrast-enhanced DANTE T1-SPACE is a very useful option in the follow-up of aneurysms after FD treatment.

OpenFOAM simulations for development of a mist flow diverter in aerosol jet printing

OpenFOAM simulations for development of a mist flow diverter in aerosol jet printing

Management of a Twisted Flow Diverting Stent With a Balloon Mounted Cardiac Stent in a Pediatric Aneurysm: A Technical Report.

Giant aneurysms can present technical challenges during treatment with flow diversion including inability to access the aneurysm outflow directly. Encircling the aneurysm with a microwire/microcatheter has been well described; however, it can result in a twisted stent because of catheter twisting during the reduction maneuver, which, in turn, could lead to thromboembolic complications. Here, we describe a novel technique to manage the twist of the flow diverter in a giant internal carotid artery aneurysm using a combination of angioplasty and off-label placement of a balloon-mounted cardiac stent within the flow diverter. At 1 year, the aneurysm is completely occluded on digital subtraction angiography and MRI, and the patient is neurologically intact.