Reduction of Intra-Aneurysmal Kinetic Energy by Intralumenal Flow Diverting Devices

2007 ◽  
Author(s):  
Jaehoon Seong ◽  
Baruch B. Lieber ◽  
Ajay K. Wakhloo
Keyword(s):  
Conclusive Evidence ◽  
Endovascular Coiling ◽  
Parent Vessel ◽  
Aneurysm Neck ◽  
Custom Made ◽  
Aneurysm Occlusion ◽  
Flow Activity ◽  
Wide Neck

Endovascular coiling is an acceptable treatment of intracranial aneurysms yet long term follow-ups suggest that endovascular coiling fails to achieve complete aneurysm occlusion particularly in wide-neck and giant aneurysms. Flow diverting devices can serve as an alternative to coils in endovascular bypass of human brain aneurysms for their exclusion from the cerebral circulation. They can redirect flow away from the aneurysm distally into the parent vessel thereby reestablishing physiological flow patterns. Placing of a flow diverting device across the aneurysm neck may be sufficient to occlude the aneurysm by promoting intra-aneurysmal thrombosis, however, conclusive evidence of its efficacy are still lacking. In this study [1], we investigated in vitro the efficacy of custom designed flow diverting devices and develop indices of their performance in an elastomeric model of the elastase-induced aneurysm in rabbit. The efficacy of custom designed flow divertors is investigated in terms of reducing the flow activity inside the sac. These custom made devices possess porosities that are similar to available stents, however, their pore densities are much higher. The results will help optimize the device that will be used in the animal model.

Microcatheter Neck Bridging and Incorporated Branch Vessel Protection for Coil Embolization of a Wide-Neck Ruptured Aneurysm: Technical Case Report

2011 ◽  
Vol 68 (suppl_1) ◽  
pp. ons40-ons44 ◽  
Author(s):  
Ajeet Gordhan
Keyword(s):  
Artery Aneurysm ◽  
Posterior Communicating Artery ◽  
Endovascular Coiling ◽  
Parent Vessel ◽  
Aneurysm Neck ◽  
Guglielmi Detachable Coil ◽  
Fisher Grade ◽  
Branch Vessel ◽  
Posterior Communicating Artery Aneurysm ◽  
Wide Neck

Abstract BACKGROUND AND IMPORTANCE: A novel technique in which microcatheter neck bridging of a ruptured wide-neck posterior communicating artery aneurysm was performed by intra-aneurysmal catheter navigation into a fetal configuration posterior cerebral artery (PCA) branch vessel arising from the sac. CLINICAL PRESENTATION: An 88-year-old woman with a Hunt and Hess grade 1 and Fisher grade 4 subarachnoid hemorrhage was identified as having a wide-neck posterior communicating artery aneurysm and an isolated fetal configuration PCA with origins from the aneurysm sac. Delivery of a bare platinum Guglielmi detachable coil within the aneurysm lumen resulted in persistent coil prolapse into the parent vessel with occlusion of the incorporated vital PCA origin. A microcatheter was then navigated through the aneurysm lumen and into the fetal configuration PCA. This was retained within the PCA with resultant aneurysm neck narrowing and branch vessel protection. A second microcatheter was placed in the aneurysm lumen for coil delivery. Complete aneurysm occlusion with patency of the PCA without coil loop prolapse into the parent vessel was achieved. CONCLUSION: The presence of normal branch vessels arising from the dome is a limitation for endovascular techniques. To the best of our knowledge, no prior description of a dual-microcatheter technique with selective catheter placement within an important intra-aneurysmal branch vessel has been published. The vital branch vessel was protected and the wide-neck aneurysm completely occluded. Novel placement of microcatheters further expands the range of complex configuration aneurysms amenable to endovascular coiling.

Preliminary In Vitro Estimates of Intra-Aneurysmal Void Sizes After Endovascular Coiling

2011 ◽  
Author(s):  
B. B. Lieber ◽  
C. Sadasivan ◽  
D. J. Fiorella ◽  
H. H. Woo ◽  
J. Brownstein ◽  
...  
Keyword(s):  
Cardiac Cycle ◽  
Density Ratio ◽  
Cerebral Aneurysms ◽  
Quantitative Measure ◽  
Treatment Method ◽  
Endovascular Coiling ◽  
Aneurysm Neck ◽  
Wide Neck ◽  
Packing Densities

Endovascular coiling has become a well-established treatment method for cerebral aneurysms. The primary drawback of the technique is aneurysm recanalization requiring periodic angiographic follow-ups and possible aneurysm re-treatment. A recent review [1] estimates that 20% of treated aneurysms re-canalize and that half of those aneurysms (10%) are re-treated. Aneurysm recanalization is, in turn, largely caused by compaction of the coil mass due to hemodynamic impingement forces every cardiac cycle. Currently, the only quantitative measure used to characterize effectiveness of the treatment is the aneurysm packing density (ratio of total volume of coils inserted into the aneurysm and the volume of the aneurysm). Lower packing densities have been correlated with higher coil compaction rates [2], so aneurysms are generally coiled to maximal packing. A wider aneurysm neck is also correlated with higher coil-compaction rates. Coiling in such wide-neck aneurysms is performed either with the support of a balloon that is removed post-coiling or with the support of an intracranial stent that is implanted. Such assist devices also improve aneurysm packing densities [3].

scholarly journals Endovascular Treatment of Small Ruptured Intracranial Aneurysms (<5 mm)

2019 ◽  
Vol 30 (4) ◽  
pp. 817-826
Author(s):  
Fei Peng ◽  
Xin Feng ◽  
Xin Tong ◽  
Baorui Zhang ◽  
Luyao Wang ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Intracranial Aneurysms ◽  
Cox Proportional Hazards ◽  
Parent Artery ◽  
Parent Vessel ◽  
Fisher Grade ◽  
Wide Neck ◽  
Ruptured Intracranial Aneurysms

Abstract Purpose To investigate the long-term clinical and angiographic outcomes and their related predictors in endovascular treatment (EVT) of small (<5 mm) ruptured intracranial aneurysms (SRA). Methods The study retrospectively reviewed patients with SRAs who underwent EVT between September 2011 and December 2016 in two Chinese stroke centers. Medical charts and telephone call follow-up were used to identify the overall unfavorable clinical outcomes (OUCO, modified Rankin score ≤2) and any recanalization or retreatment. The independent predictors of OUCO and recanalization were studied using univariate and multivariate analyses. Multivariate Cox proportional hazards models were used to identify the predictors of retreatment. Results In this study 272 SRAs were included with a median follow-up period of 5.0 years (interquartile range 3.5–6.5 years) and 231 patients with over 1171 aneurysm-years were contacted. Among these, OUCO, recanalization, and retreatment occurred in 20 (7.4%), 24 (12.8%), and 11 (7.1%) patients, respectively. Aneurysms accompanied by parent vessel stenosis (AAPVS), high Hunt-Hess grade, high Fisher grade, and intraoperative thrombogenesis in the parent artery (ITPA) were the independent predictors of OUCO. A wide neck was found to be a predictor of recanalization. The 11 retreatments included 1 case of surgical clipping, 6 cases of coiling, and 4 cases of stent-assisted coiling. A wide neck and AAPVS were the related predictors. Conclusion The present study demonstrated relatively favorable clinical and angiographic outcomes in EVT of SRAs in long-term follow-up of up to 5 years. THE AAPVS, as a morphological indicator of the parent artery for both OUCO and retreatment, needs further validation.

STENT REMODELING TECHNIQUE FOR COILING OF RUPTURED WIDE-NECK CEREBRAL ANEURYSMS: CASE REPORT

Neurosurgery ◽  
2009 ◽  
Vol 65 (5) ◽  
pp. E1007-E1008 ◽  
Author(s):  
Demetrius K. Lopes ◽  
Kalani Wells
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Aneurysms ◽  
Artery Aneurysm ◽  
Anterior Communicating Artery ◽  
Parent Vessel ◽  
Aneurysm Neck ◽  
Acute Subarachnoid Hemorrhage ◽  
The Right ◽  
Wide Neck ◽  
Cordis Corporation

Abstract OBJECTIVE To describe a novel stent remodeling technique for the coiling of ruptured wide-neck cerebral aneurysms. CLINICAL PRESENTATION A 46-year-old man presented with acute subarachnoid hemorrhage (Hunt and Hess grade IV), intracerebral hemorrhage, and hydrocephalus. Cerebral angiography revealed a wide-neck small anterior communicating artery aneurysm. Conventional coiling was not successful because of coil instability and compromise of the dominant anterior cerebral artery. TECHNIQUE A 6-French shuttle sheath (Cook Medical, Indianapolis, IN) was advanced from a right femoral approach into the right common carotid artery. To protect the parent vessel during coiling without compromising blood flow, a Prowler Select Plus catheter (Cordis Corporation, Bridgewater, NJ) was navigated across the aneurysm neck. Subsequently, an Enterprise stent (22-mm length; Cordis Corporation) was partially deployed across the aneurysm's wide neck. It was very important to watch the distal markers of the stent and lock the stent delivery wire to the Prowler Select Plus with a hemostatic valve once the stent was halfway deployed. This maneuver was essential to prevent further deployment of the stent. The SL-10 microcatheter and Synchro 14 wire (Boston Scientific, Natick, MA) were carefully navigated to the aneurysm passing through the partially deployed stent. Coils were then delivered to the aneurysm using the stent as a scaffold. After coiling, the SL-10 microcatheter was removed and the stent was recaptured into the Prowler Select Plus catheter. During the recapture, there was initial resistance. This was easily overcome after deploying the stent a little more before resheathing. During the procedure, the patient received 2000 U of heparin after the first coil was detached in the aneurysm. CONCLUSION The stent remodeling technique is a novel endovascular technique that can be used to treat ruptured wide-neck aneurysms and maintain patency of parent vessels, avoiding the use of antiplatelet therapy in acute subarachnoid hemorrhage.

Cellular responses to flow diverters in a tissue-engineered aneurysm model

2020 ◽  
pp. neurintsurg-2020-016593
Author(s):  
Wenjing Liu ◽  
Daying Dai ◽  
Yong-Hong Ding ◽  
Yang Liu ◽  
Kristen Temnyk ◽  
...  
Keyword(s):  
Cellular Responses ◽  
Parent Vessel ◽  
Aortic Endothelial Cells ◽  
Aneurysm Neck ◽  
Aortic Smooth Muscle ◽  
Cell Coverage ◽  
Human Aortic Endothelial Cells ◽  
Aneurysm Model ◽  
Flow Diverters

BackgroundNotwithstanding the widespread implementation of flow diverters (FDs) in the treatment of intracranial aneurysms, the exact mechanism of action of these devices remains elusive. We aimed to advance the understanding of cellular responses to FD implantation using a 3D tissue-engineered in vitro aneurysm model.MethodsAneurysm-like blood vessel mimics (aBVMs) were constructed by electrospinning polycaprolactone nanofibers onto desired aneurysm-like geometries. aBVMs were seeded with human aortic smooth muscle cells (SMCs) followed by human aortic endothelial cells (ECs). FDs were then deployed in the parent vessel of aBVMs covering the aneurysm neck and were cultivated for 7, 14, or 28 days (n=3 for each time point). The EC and SMC coverage in the neck was measured semi-quantitatively.ResultsAt day 7, the device segment in contact with the parent vessel was partially endothelialized. Also, the majority of device struts, but not pores, at the parent vessel and neck interface were partially covered with ECs and SMCs, while device struts in the middle of the neck lacked cell coverage. At 14 days, histology verified a neointimal-like lining had formed, partially covering both the struts and pores in the center of the neck. At 28 days, the majority of the neck was covered with a translucent neointimal-like layer. A higher degree of cellular coverage was seen on the struts and pores at the neck at 28 days compared with both 7 and 14 days.ConclusionaBVMs can be a valuable alternative tool for evaluating the healing mechanisms of endovascular aneurysm devices.

scholarly journals In Vitro Reproduction of Device Deformation Leading to Thrombotic Complications and Failure of Flow Diversion

2013 ◽  
Vol 19 (4) ◽  
pp. 432-437 ◽  
Author(s):  
Laurent Estrade ◽  
Alina Makoyeva ◽  
Tim E. Darsaut ◽  
Jimmy Ghostine ◽  
Evgueni Kouznetsov ◽  
...  
Keyword(s):  
Thrombotic Complication ◽  
Parent Vessel ◽  
Landing Zone ◽  
Aneurysm Neck ◽  
Recipient Vessel ◽  
Clinical Consequences ◽  
Thrombotic Complications ◽  
Residual Flows ◽  
The Relationship

Flow diverters (FDs) are increasingly used for complex intracranial aneurysms. As these self-expanding devices are deployed across an aneurysm neck, they can undergo deformations. The potential clinical consequences of FD deformations remain unclear. We describe an immediate thrombotic complication attributed to a stereotypical stenotic deformation of an FD extremity that can occur when landing zones are of insufficient length. This case is supplemented with in vitro studies showing the relationship between i) the length of the landing zones and ii) discrepancies between the diameter of the device and recipient vessel, and the severity of FD stenosis. In vitro, a shorter landing zone was associated with a progressive stenotic deformation of the terminal ends of all FDs studied. This deformation was more pronounced when the diameter of the device was oversized compared to the size of the recipient tube. In our clinical case, the presence of this deformation led to an immediate thrombotic complication, requiring deployment of a second stent to correct the observed stenosis. In addition, treatment failure ultimately led to a fatal rupture, a failure that can be explained by residual flows through a more porous transition zone, another characteristic FD deformation which occurs when they are oversized as compared to the parent vessel, but free to expand at the level of the aneurysm. Proper selection of device diameter and length of the landing zone is important, and may decrease the incidence of deformation-related complications.

The Role of Blood Impulse in Cerebral Aneurysm Coil Compaction: Effect of Aneurysm Neck Size

2003 ◽  
Author(s):  
Baruch B. Lieber ◽  
Chander Sadasivan ◽  
Matthew J. Gounis ◽  
Ajay K. Wakhloo
Keyword(s):  
Cerebral Aneurysms ◽  
Momentum Equation ◽  
Parent Vessel ◽  
Neck Size ◽  
Aneurysm Neck ◽  
Hemodynamic Forces ◽  
Sigmoid Curve ◽  
Detachable Coils ◽  
Aneurysm Volume

Endovascular occlusion of cerebral aneurysms with bare platinum detachable coils is now recognized as preferable to surgical clipping (ISUIA Group, 2003, ISAT Group, 2002, Bavinzski et al, 1995, Thornton et al, 2002). Dependent on coil packing density (the ratio of the coil volume deposited in an aneurysm to that of the aneurysm volume), aneurysm location, size and neck width, coil compaction with recanalization of the aneurysm remains in the long-term a major concern. The aneurysm neck size is reported to be the main predictor for aneurysm recanalization (Fernandez-Zubillaga et al, 1994). The forces exerted on the coil mass at the aneurysm neck due to blood pulsatility are larger for wide neck aneurysms as compared to small neck aneurysms (Bavinzski et al, 1995). However, impingement forces have not been evaluated. We evaluated the force impinging on the aneurysm neck in a simplified aneurysm (basilar top) geometry utilizing the impulse-momentum equation and Womersley’s flow. Maximum impingement force as a function of aneurysm neck to parent lumen diameter ratio varies as a sigmoid curve. Analysis of the hemodynamic forces affecting coil compaction in cerebral aneurysms shows that the coil mass at the aneurysm neck may be subjected to cyclic impulse impingement due to redirection of blood momentum. Orientation of the aneurysm neck and the main axis of the aneurysm in relation to the oncoming parent vessel flow may help clinicians predict the risk of coil compaction and the location of subsequent aneurysm recanalization.

Stress Relaxation of Porcine Gluteus Muscle Subjected to Sudden Transverse Deformation as Related to Pressure Sore Modeling

2006 ◽  
Vol 128 (5) ◽  
pp. 782-787 ◽  
Author(s):  
Avital Palevski ◽  
Ittai Glaich ◽  
Sigal Portnoy ◽  
Eran Linder-Ganz ◽  
Amit Gefen
Keyword(s):  
Stress Relaxation ◽  
Correlation Coefficients ◽  
Pressure Sore ◽  
Short Term ◽  
Shear Moduli ◽  
Custom Made ◽  
Gluteus Muscle ◽  
Relaxation Curves

Computational studies of deep pressure sores (DPS) in skeletal muscles require information on viscoelastic constitutive behavior of muscles, particularly when muscles are loaded transversally as during bone-muscle interaction in sitting and lying immobilized patients. In this study, we measured transient shear moduli G(t) of fresh porcine muscles in vitro using the indentation method. We employed a custom-made pneumatic device that allowed rapid (2000mm∕s)4mm indentations. We tested 8 gluteus muscles, harvested from 5 adult pigs. Each muscle was indented transversally (perpendicularly to the direction of fibers) at 3 different sites, 7 times per site, to obtain nonpreconditioned (NPC) and preconditioned (PC) G(t) data. Short-term (GS) and long-term (GL) shear moduli were obtained directly from experiments. We further fitted measured G(t) data to a biexponential equation G(t)=G1∙exp(−t∕τ1)+G2∙exp(−t∕τ2)+G∞, which provided good fit, visually and in terms of the correlation coefficients. Typically, plateau of the stress relaxation curves (defined as 10% difference from final GL) was evident ∼20s after indentation. Short-term shear moduli GS (mean NPC: 8509Pa, PC: 5711Pa) were greater than long-term moduli GL (NPC: 609Pa, PC: 807Pa) by about an order of magnitude. Statistical analysis of parameters showed that only G2 was affected by preconditioning, while GL, GS, G∞, τ1, τ2, and G1 properties were unaffected. Since DPS develop over time scales of minutes to hours, but most stress relaxation occurs within ∼20s, the most relevant property for computational modeling is GL (mean ∼700Pa), which is, conveniently, unaffected by preconditioning.

scholarly journals Multiple pipeline twists encountered during treatment of a symptomatic fusiform ICA aneurysm

2019 ◽  
Vol 12 (7) ◽  
pp. e230036 ◽  
Author(s):  
Robert W Young ◽  
Matthew T Bender ◽  
Geoffrey P Colby ◽  
Alexander L Coon
Keyword(s):  
Internal Carotid ◽  
Thrombus Formation ◽  
Artery Aneurysm ◽  
Long Term Outcomes ◽  
Parent Vessel ◽  
Carotid Artery Aneurysm ◽  
Internal Carotid Artery Aneurysm ◽  
Aneurysm Occlusion

Pipeline embolisation device (PED) ‘twisting’ is an intra-operative complication that manifests with the appearance of a ‘figure-8’ in perpendicular planes on digital subtraction angiography. A twisted PED causes narrowing and/or complete occlusion of the vessel lumen and poses significant risks for thrombus formation and downstream ischaemia. Here, we present a case in which three unique PED implants become twisted during pipeline embolisation of a large fusiform internal carotid artery aneurysm. The twists were remediated by balloon angioplasty and a combination of techniques that allowed the PED to rotate and restore its original axis. Six-month and twelve-month follow-up angiography demonstrated complete aneurysm occlusion with preservation of the parent vessel, proving that proper remediation of PED twisting can still result in successful long-term outcomes.

Flow diversion of bifurcation aneurysms is more effective when the jailed branch is occluded: an experimental study in a novel canine model

2016 ◽  
Vol 9 (3) ◽  
pp. 311-315 ◽  
Author(s):  
R Fahed ◽  
J C Gentric ◽  
I Salazkin ◽  
G Gevry ◽  
J Raymond ◽  
...  
Keyword(s):  
Canine Model ◽  
Flow Diversion ◽  
Ordinal Scale ◽  
Parent Vessel ◽  
Aneurysm Neck ◽  
Bifurcation Aneurysm ◽  
Vessel Stenosis ◽  
Aneurysm Occlusion ◽  
Neointimal Coverage

BackgroundFlow 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. Our aim was to test whether endovascular occlusion of the jailed branch could improve efficacy of flow diversion of bifurcation aneurysms.Materials and methodsSixteen wide-necked lingual–carotid artery bifurcation aneurysms were created in eight 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 3 months were scored using an ordinal scale. Pathology specimens were photographed and neointimal coverage estimated using a semiquantitative scoring system.ResultsFourteen aneurysms were patent at 1 month. FD deployment was successful in all cases but, at 3-month follow-up, three 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 compared with flow diversion alone (median angiographic scores 2 vs 0: p=0.0137). Flow-limiting parent vessel stenosis was not observed in any arteries. Devices were covered with thick neointima in most cases, but patent aneurysms were associated with leaks or holes in the neointima covering the aneurysm neck.ConclusionsTreatment 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 scores of a canine bifurcation aneurysm model.

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