Flow Diversion in Rabbit Aneurysm Models

Author(s):  
Juan R. Cebral ◽  
Fernando Mut ◽  
Marcelo Raschi ◽  
Ramanathan Kadirvel ◽  
David Kallmes

Flow diversion treatment of cerebral aneurysms has increasingly been considered, especially for large complex aneurysms with wide necks that are difficult to treat with coils of by clipping. However, the relationship between the hemodynamic environment created immediately after implantation of flow diverters (FD) and the subsequent aneurysm occlusion is poorly understood [1].

Neurosurgery ◽  
2019 ◽  
Vol 86 (Supplement_1) ◽  
pp. S36-S45 ◽  
Author(s):  
Bree Chancellor ◽  
Eytan Raz ◽  
Maksim Shapiro ◽  
Omar Tanweer ◽  
Erez Nossek ◽  
...  

Abstract Flow diverters (FDs) have changed the management of brain aneurysms; not only for complex aneurysms (giant, fusiform and blister) refractory to conventional therapies, but also for unruptured lesions previously managed by traditional surgical or coil-based endovascular methods. Since 2011 when the PipelineTM Embolization Device (Medtronic) was cleared by the Food and Drug Administration for adults with large or giant wide-neck intracranial aneurysms of the internal carotid artery proximal to the posterior communicating segment, the role of flow diversion for aneurysm treatment has expanded—supported by favorably low complication and high cure rates compared with alternative treatments. Here we review the key clinical trials and the long term outcomes that have demonstrated safety and efficacy of minimized porosity endoluminal devices in the treatment of cerebral aneurysms.


2019 ◽  
Vol 25 (6) ◽  
pp. 655-663 ◽  
Author(s):  
Chander Sadasivan ◽  
Ronak Dholakia ◽  
Lissa Peeling ◽  
Philipp Gölitz ◽  
Arnd Doerfler ◽  
...  

Background The recent growth of neuro-endovascular treatment has rekindled interest in the use of angiographic techniques for flow assessment. Aneurysm treatment with flow diverters is particularly amenable to such analysis. We analyze contrast time–density curves — recorded within aneurysms before (pre) and immediately after (post) flow diverter implantation to estimate six-month treatment outcomes. Methods Fifty-six patients with 65 aneurysms were treated with flow diverters at two institutions. A region of interest was drawn around the aneurysm perimeter in image sequences taken both pre and post angiography, and the temporal variation in grayscale intensity within the aneurysm (time–density curve) was recorded. Eleven parameters were quantified from each time–density curve. Aneurysm occlusion status was recorded six months post treatment. The change in parameters from pre to post treatment was statistically evaluated between aneurysm occluded and non-occluded groups. Results Of the 11 parameters, eight were significantly different before and immediately after flow diversion. Considering the entire data set, none of the parameters was statistically different between the occluded and non-occluded groups. However, subgroup analyses showed that four variables were significantly different between the aneurysm occluded and non-occluded groups. The sensitivity of these variables to predict aneurysm occlusion at six months ranged from 60% to 89%, while the specificity ranged from 55% to 70%. Conclusions Device-induced intra-aneurysmal flow alterations quantified by simple aneurysmal time–density curves can potentially be used to predict long-term outcomes of flow diversion. Large multi-center studies will be required to confirm these findings. Patient-to-patient variability in coagulation may need to be incorporated for clinically relevant predictive values.


2020 ◽  
Vol 26 (4) ◽  
pp. 468-475 ◽  
Author(s):  
Ahmed E Hussein ◽  
Meghana Shownkeen ◽  
Andre Thomas ◽  
Christopher Stapleton ◽  
Denise Brunozzi ◽  
...  

Objective Indications for the treatment of cerebral aneurysms with flow diversion stents are expanding. The current aneurysm occlusion rate at six months ranges between 60 and 80%. Predictability of complete vs. partial aneurysm occlusion is poorly defined. Here, we evaluate the angiographic contrast time-density as a predictor of aneurysm occlusion rate at six months’ post-flow diversion stents. Methods Patients with unruptured cerebral aneurysms proximal to the internal carotid artery terminus treated with single flow diversion stents were included. 2D parametric parenchymal blood flow software (Siemens-Healthineers, Forchheim, Germany) was used to calculate contrast time-density within the aneurysm and in the proximal adjacent internal carotid artery. The area under the curve ratio between the two regions of interests was assessed at baseline and after flow diversion stents deployment. The area under the curve ratio between completely vs. partially occluded aneurysms at six months’ follow-up was compared. Results Thirty patients with 31 aneurysms were included. Mean aneurysm diameter was 8 mm (range 2–28 mm). Complete occlusion was obtained in 19 aneurysms. Younger patients ( P = 0.006) and smaller aneurysms ( P = 0.046) presented higher chance of complete obliteration. Incomplete occlusion of the aneurysm was more likely if the area under the curve contrast time-density ratio showed absolute ( P = 0.001) and relative percentage ( P = 0.001) decrease after flow diversion stents deployment. Area under ROC curve was 0.85. Conclusion Negative change in the area under the curve ratio indicates less contrast stagnation in the aneurysm and lower chance of occlusion. These data provide a real-time analysis after aneurysm treatment. If validated in larger datasets, this can prompt input to the surgeon to place a second flow diversion stents.


Author(s):  
Marcelo Bolcato ◽  
ana Carolina Dalmonico ◽  
Leo Ditzel ◽  
Savio Machareti ◽  
Thiago Yoshida ◽  
...  

Introduction : Endovascular flow diverters are increasingly used for the treatment of cerebral aneurysms. We assessed the safety and efficacy of the Flow Diverters in a consecutive series of 53 patients and 60 aneurysms. Methods : Inclusion criteria were wide‐neck, blister‐like, or fusiform aneurysms independent of size, treated with the FRED, PIPELINE and SILK between December 2014 and Junho 2021. Assessment criteria were aneurysm occlusion, manifest ischemic stroke, bleeding, or death. The occlusion rate was assessed at 6 months and 1 year with DSA by using the Raymond classification and the O'Kelly‐Marotta grading scale. Results : Fifty three patients (mean age 54.3 years;81.1% female) with 60 aneurysms were treated with 9 Silk, 38 FREDs and 13 Pipeline. Aneurysm size ranged from 2.5 to 30 mm. Deployment of the Flow diverters was successful in 52 aneurysms. Three patient developed mild stroke symptoms that fully receded within days, 4 patients occlusion total carotid because resistant antiagregation and another patient’s development Swelling syndrome. There has been one death. Initial follow‐up at 6 months showed complete occlusion in 90% of the overall study group and 93,33% at 1 year. Conclusions : The flow diverter is a safe device for the treatment of cerebral aneurysms of various types. Our data reveal high occlusion rates at 6 months and 1 year. Long‐term occlusion rates are expected.


2017 ◽  
Vol 42 (6) ◽  
pp. E2 ◽  
Author(s):  
Gary Rajah ◽  
Sandra Narayanan ◽  
Leonardo Rangel-Castilla

Flow diversion has become a well-accepted option for the treatment of cerebral aneurysms. Given the significant treatment effect of flow diverters, numerous options have emerged since the initial Pipeline embolization device studies. In this review, the authors describe the available flow diverters, both endoluminal and intrasaccular, addressing nuances of device design and function and presenting data on complications and outcomes, where available. They also discuss possible future directions of flow diversion.


2019 ◽  
Vol 12 (6) ◽  
pp. 616-620 ◽  
Author(s):  
Chander Sadasivan ◽  
David Fiorella

Background and purposeFlow diverters are increasingly used to treat a broad category of cerebral aneurysms. We conducted an in vitro study to angiographically compare the flow diversion effect of Surpass Evolve from Stryker Neurovascular with the Pipeline Shield Embolization Device from Medtronic Neurovascular.MethodsThree copies each of three carotid aneurysm geometries were manufactured from silicone. Evolve and Pipeline flow diverters were deployed in one copy of each geometry; the third copy was used as Control. High-speed angiography was acquired under pulsatile flow in each replica, contrast concentration-time curves within the aneurysms were recorded, and the curves were quantified with six parameters. The parameters were statistically evaluated to compare the flow diversion effect of both devices.ResultsThe Evolve showed greater flow diversion trends in almost all intra-geometry comparisons than the Pipeline. When aggregated over the three geometries, the Evolve was statistically significantly better than the Pipeline in four of the six parameters, and about the same or better (not statistically significant) than the Pipeline in the other two parameters.ConclusionsThe Evolve device demonstrated greater in vitro flow diversion effects than Pipeline. Comparative efficacy of the devices will need to be adjudicated based on clinical outcomes.


2020 ◽  
pp. 1-10
Author(s):  
Adam A. Dmytriw ◽  
Anish Kapadia ◽  
Alejandro Enriquez-Marulanda ◽  
Carmen Parra-Fariñas ◽  
Anna Luisa Kühn ◽  
...  

OBJECTIVECoverage of the anterior spinal artery (ASA) ostia is a source of considerable consternation regarding flow diversion (FD) in vertebral artery (VA) aneurysms due to cord supply. The authors sought to assess the association between coverage of the ASA, posterior spinal artery (PSA), or lateral spinal artery (LSA) ostia when placing flow diverters in distal VAs and clinical outcomes, with emphasis on cord infarction.METHODSA multicenter retrospective study of 7 institutions in which VA aneurysms were treated with FD between 2011 and 2019 was performed. The authors evaluated the risk of ASA and PSA/LSA occlusion, associated thromboembolic complication, complications overall, aneurysm occlusion status, and functional outcome.RESULTSSixty patients with 63 VA and posterior inferior cerebellar artery aneurysms treated with FD were identified. The median aneurysm diameter was 7 mm and fusiform type was the commonest morphology (42.9%). During a procedure, 1 (61.7%) or 2 (33.3%) flow diverters were placed. Complete occlusion was achieved in 71.9%. Symptomatic thromboembolic complications occurred in 7.4% of cases and intracranial hemorrhage in 10.0% of cases. The ASA and PSA/LSA were identified in 51 (80.9%) and 35 (55.6%) complications and covered by the flow diverter in 29 (56.9%) and 13 (37.1%) of the procedures, respectively. Patency after flow diverter coverage on last follow-up was 89.2% for ASA and 100% for PSA/LSA, not significantly different between covered and noncovered groups (p = 0.5 and p > 0.99, respectively). No complications arose from coverage.CONCLUSIONSFD aneurysm treatment in the posterior circulation with coverage of ASA or PSA/LSA was not associated with higher rates of occlusion of these branches or any instances of cord infarction.


Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Nohra Chalouhi ◽  
Guilherme Barros ◽  
Stavropoula Tjoumakaris ◽  
Ayan Kumar ◽  
Michael Lang ◽  
...  

Background: Aneurysm recurrence after coil therapy remains a major shortcoming in the endovascular management of cerebral aneurysms. Flow diversion has emerged as a promising treatment for intracranial aneurysms. The safety and efficacy of this new technology is under investigation. The current study assesses the yield of further angiographic follow-up in aneurysms that have achieved adequate occlusion after treatment with the Pipeline Embolization Device (PED). Methods: Inclusion criteria were as follows: 1) treatment of one or more aneurysms with the PED, 2) available short-term (<12 months) follow-up digital subtraction angiography (DSA), 3) complete (100%) or near-complete (>95%) occlusion on short-term follow-up DSA, and 4) available further angiographic follow-up (DSA or MRA). Results: A total of 175 patients matching the inclusion criteria were identified. Aneurysm size was 9.0 mm on average. Mean angiographic follow-up was 23.4 months. On short-term follow-up DSA images, 154 (88%) had complete aneurysm occlusion and 21 (12%) had near-complete occlusion. Seven patients (4%) had further DSA follow-up alone, 39 patients (22%) had further DSA and MRA follow-up, and 129 patients (74%) had further MRA follow-up alone. On further angiographic follow-up (DSA or MRA), no patient had a decrease in the degree of aneurysm occlusion (recurrence) or required retreatment. Of the 21 patients with near-complete occlusion on initial DSA images, 5 patients (24%) progressed to complete aneurysm occlusion on further angiographic follow-up. No patient had evidence of new in-stent stenosis on further angiographic follow-up. Conclusion: In this study, the diagnostic yield of repeat angiography in adequately occluded aneurysms with the PED was very low. Based on these findings, we do not recommend further angiographic follow-up once aneurysms have achieved adequate occlusion with the PED.


Author(s):  
T Darsaut ◽  
R Fahed ◽  
G Gevry ◽  
J Gentric ◽  
I Salazkin ◽  
...  

Background: Flow diverters (FDs) are increasingly used for bifurcation aneurysms. Failure of aneurysm occlusion may be caused by residual flow maintaining patency of the jailed branch along with the aneurysm. Methods: Sixteen wide-necked lingual-carotid artery bifurcation aneurysms were created in 8 canines. Patent aneurysms were randomly allocated 4 weeks later to flow diversion combined with jailed branch occlusion using coils and/or Onyx (n=6) or flow diversion alone (n=8). Angiographic results of aneurysm occlusion at three months were scored using an ordinal scale. Pathology specimens were photographed and neointimal coverage estimated. Results: Fourteen aneurysms were patent at one month. FD deployment was successful in all cases, but at 3 month follow-up, 3 devices had prolapsed into the aneurysm. None of the bifurcation aneurysms treated with FD alone were occluded at 3 months. Endovascular branch occlusion combined with flow diversion significantly improved aneurysm occlusion rates (median angiographic score of 2) compared to flow diversion alone (median score of 0: P=0.0137). Flow-limiting parent vessel stenosis was not observed in any arteries. Devices were covered with thick neointima in most cases. Conclusions: Treatment failures following flow diversion of bifurcation aneurysms can be caused by persistent flow to the jailed branch. Branch occlusion combined with flow diversion may improve angiographic occlusion of canine aneurysms.


2017 ◽  
Vol 10 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Cameron M McDougall ◽  
Khurshid Khan ◽  
Maher Saqqur ◽  
Andrew Jack ◽  
Jeremy Rempel ◽  
...  

Background and purposeFlow diversion is a relatively new strategy used to treat complex cerebral aneurysms. The optimal method for radiographic follow-up of patients treated with flow diverters has not been established. The rate and clinical implications of in-stent stenosis for these devices is unclear. We evaluate the use of transcranial Doppler ultrasound (TCD) for follow-up of in-stent stenosis.Materials and methodsWe analyzed 28 patients treated with the Pipeline embolization device (PED) over the course of 42 months from January 2009 to June 2012. Standard conventional cerebral angiograms were performed in all patients. TCD studies were available in 23 patients.ResultsAngiographic and TCD results were compared and found to correlate well.ConclusionsTCD is a potentially useful adjunct for evaluating in-stent stenosis after flow diversion.


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