Relationships between geometrical parameters and mechanical properties for a helical braided flow diverter stent

2017 ◽  
Vol 25 (4) ◽  
pp. 611-623 ◽  
Author(s):  
Takashi Suzuki ◽  
Hiroyuki Takao ◽  
Soichiro Fujimura ◽  
Chihebeddine Dahmani ◽  
Toshihiro Ishibashi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flow Diverter ◽  
Geometrical Parameters ◽  
Flow Diverter Stent

scholarly journals Selection of helical braided flow diverter stents based on hemodynamic performance and mechanical properties

2016 ◽  
Vol 9 (10) ◽  
pp. 999-1005 ◽  
Author(s):  
Takashi Suzuki ◽  
Hiroyuki Takao ◽  
Soichiro Fujimura ◽  
Chihebeddine Dahmani ◽  
Toshihiro Ishibashi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reduction Rate ◽  
Flow Diverter ◽  
Outer Diameter ◽  
Cfd Simulations ◽  
Flow Reduction ◽  
Radial Stiffness ◽  
Flow Diverter Stent ◽  
Hemodynamic Performance ◽  
Longitudinal Flexibility

BackgroundAlthough flow diversion is a promising procedure for the treatment of aneurysms, complications have been reported and it remains poorly understood. The occurrence of adverse outcomes is known to depend on both the mechanical properties and flow reduction effects of the flow diverter stent.ObjectiveTo clarify the possibility of designing a flow diverter stent considering both hemodynamic performance and mechanical properties.Materials and methodsComputational fluid dynamics (CFD) simulations were conducted based on an ideal aneurysm model with flow diverters. Structural analyses of two flow diverter models exhibiting similar flow reduction effects were performed, and the radial stiffness and longitudinal flexibility were compared.ResultsIn CFD simulations, two stents–Pore2-d35 (26.77° weave angle when fully expanded, 35 μm wire thickness) and Pore3-d50 (36.65°, 50 μm respectively)–demonstrated similar flow reduction rates (68.5% spatial-averaged velocity reduction rate, 85.0% area-averaged wall shear stress reduction rate for Pore2-d35, and 68.6%, 85.4%, respectively, for Pore3-d50). However, Pore3-d50 exhibited greater radial stiffness than Pore2-d35 (40.0 vs 21.0 mN/m at a 3.5 mm outer diameter) and less longitudinal flexibility (0.903 vs 0.104 N·mm bending moments at 90°). These measurements indicate that changing the wire thickness and weave angle allows adjustment of the mechanical properties while maintaining the same degree of flow reduction effects.ConclusionsThe combination of CFD and structural analysis can provide promising solutions for an optimized stent. Stents exhibiting different mechanical properties but the same flow reduction effects could be designed by varying both the weave angle and wire thickness.

A Computational Modelling for Hemodynamic Conditions Following Flow-Diverting Treatment in Cerebral Aneurysms

2018 ◽  
Author(s):  
Gen Fu ◽  
Alexandrina Untaroiu
Keyword(s):  
Average Velocity ◽  
Physiological State ◽  
Cerebral Aneurysms ◽  
Side Wall ◽  
Flow Diverter ◽  
Geometrical Parameters ◽  
Parent Artery ◽  
Flow Diverter Stent ◽  
Structure Of Flow ◽  
Flow Diverters

Cerebral aneurysms are abnormal dilations of blood vessels within the skull that, in some cases, may rupture and bleed. The rupture of an aneurysm can cause significant bleeding into or around the brain (a stroke). Flow diverters are specially designed low porosity stents that are deployed into the parent artery to cover the neck of the aneurysm. The dense mesh-like structure of flow diverters aims at redirecting flow from the aneurysm to the parent artery and vice versa, resulting in flow stasis in the aneurysm and promoting thrombus formation conditions. The thrombosed aneurysm is then resorbed by the body’s wound healing mechanisms-the end result of which is a remodeled vessel returned to its normal physiological state. Most previous studies have been focused on correlating the hemodynamic conditions with the outcome of the flow diverters. On the other hand, the effects of the location of the stents have not been addressed. In this study, a numerical simulation of an idealized side wall aneurysm model is used to predict the hemodynamic conditions for different flow diverter stent locations. The CFD model of the aneurysm is developed based on data from the literature and the geometrical parameters are set according to the test data. Pulsatile boundary conditions are chosen according to the normal physiological conditions. The entire stent geometry is used to model the effect of the stent on the flow characteristics. The hemodynamic conditions in the aneurysm corresponding to different stent locations are compared. The results show that the average velocity and vorticity are significantly different depending on different stent locations. Marked reduction in average velocity, average vorticity, and mean wall shear stress within the aneurysm sac have been observed even in malposition cases. The results of this study can be further used to guide the deployment of the flow diverter stent in clinical application.

Design and Mechanical Properties of a Novel Cerebral Flow Diverter Stent

2014 ◽  
Vol 42 (5) ◽  
pp. 960-970 ◽  
Author(s):  
Jiayao Ma ◽  
Zhong You ◽  
James Byrne ◽  
Rafik R. Rizkallah
Keyword(s):  
Mechanical Properties ◽  
Flow Diverter ◽  
Flow Diverter Stent

scholarly journals A realistic way to investigate the design, and mechanical properties of flow diverter stents

2021 ◽  
Author(s):  
Prasanth Velvaluri ◽  
Mariya S. Pravdivtseva ◽  
Johannes Hensler ◽  
Fritz Wodarg ◽  
Olav Jansen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flow Diverter

Management of giant internal carotid aneurysm by extracranial-intracranial bypass and flow diverter stent

2021 ◽  
pp. 1-5
Author(s):  
Assylbek Kaliyev ◽  
Yerbol Makhambetov ◽  
Yerkin Medetov ◽  
Marat Kulmirzayev ◽  
Serik Dusembayev ◽  
...  
Keyword(s):  
Internal Carotid ◽  
Flow Diverter ◽  
Flow Diverter Stent

Ocular Trauma with Ophthalmic Artery Injury as a Rare Cause of Subarachnoid Hemorrhage: a Case Report and Review of the Literature

2021 ◽  
Author(s):  
Michael Veldeman ◽  
Hani Ridwan ◽  
Dimah Hasan ◽  
Annette Rieg ◽  
Hans Clusmann ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Cerebral Ischemia ◽  
Ophthalmic Artery ◽  
Ocular Trauma ◽  
Delayed Cerebral Ischemia ◽  
Penetrating Trauma ◽  
Flow Diverter ◽  
Pseudoaneurysm Formation ◽  
Flow Diverter Stent ◽  
Close Observation

Abstract Background and Importance Traumatic avulsion of the ophthalmic artery is a rare cause of subarachnoid hemorrhage (SAH). In this case, a relative minor fall with isolated ocular trauma caused bulbar dislocation and rupture of the ophthalmic artery in its intracranial segment resulting in subarachnoid bleeding. Clinical Presentation In a female patient in her 70s, a direct penetrating trauma to the orbit by a door handle resulted in basal SAH with blood dispersion into both Sylvian fissures. Cerebral angiography revealed a blunt-ending stump at the origin of the ophthalmic artery. To provide protection against further bleeding, a flow diverter stent was placed in the internal carotid artery to cover the origin of the ophthalmic artery. After a longer intensive care stay complicated by pneumonia and respiratory insufficiency, the patient made a full recovery. Of all four reported cases (including ours), delayed cerebral ischemia was seen in one patient and hydrocephalus in two patients. These potential complications necessitate close observation and fitting treatment similar to aneurysmal SAH. Conclusion Due to similar physiologic aspects, this type of bleed mimics many aspects of aneurysmal SAH. In this case, we observed no hydrocephalus or the development of delayed cerebral ischemia. This represents, however, the first reported case treated by placement of a flow diverter stent to prevent rebleeding and pseudoaneurysm formation.

High-Resolution MRI Visualization of Aneurysmal Thrombosis after Flow Diverter Stent Placement

2014 ◽  
Vol 25 (2) ◽  
pp. 310-311 ◽  
Author(s):  
Benjamin Gory ◽  
Monica Sigovan ◽  
Carolina Vallecilla ◽  
Guy Courbebaisse ◽  
Francis Turjman
Keyword(s):  
High Resolution ◽  
Stent Placement ◽  
Flow Diverter ◽  
Flow Diverter Stent ◽  
High Resolution Mri

scholarly journals Silk flow-diverter stent for the treatment of complex intracranial aneurysms: A one-year follow-up multicenter study

2018 ◽  
Vol 24 (4) ◽  
pp. 357-362 ◽  
Author(s):  
G Foa Torres ◽  
F Roca ◽  
A Noguera ◽  
J Godes ◽  
S Petrocelli ◽  
...  
Keyword(s):  
Mortality Rates ◽  
Flow Diverter ◽  
Clinical Findings ◽  
Safe Alternative ◽  
Complex Aneurysms ◽  
Flow Diverter Stent ◽  
Class 1 ◽  
One Year ◽  
Therapeutic Alternatives

Background Flow-diverter stents have been successfully used in the treatment of complex aneurysms with limited therapeutic alternatives. We report our experience using the Silk flow diverter (SFD; Balt Extrusion, Montmorency, France) for the treatment of complex aneurysms in four Argentine centers. Methods We conducted a retrospective review of 246 consecutive patients who were treated with the SFD at four Argentine centers between January 2009 and January 2017. The patient and aneurysm characteristics, as well as the details of the procedure, were analyzed. The angiographic and clinical findings were recorded during and immediately after the procedure and at 12-month follow-up. Results Angiography follow-up at 12 months was possible in 235 patients (95.5%) with 282 aneurysms. A total of 265 aneurysms (93.9%) presented with complete occlusion of the aneurysmal sac (class 1) and 17 aneurysms (6.1%) presented with partial occlusion (class 2). The 12-month clinical follow-up showed 11 patients with major events (seven, scale 2; five, scale 3; and two, scale 4). The morbidity and mortality rates were 4.2% (11/289) and 2.1% (5/289), respectively. Conclusions The treatment of aneurysms with the SFD was associated with a low rate of complications and a high percentage of aneurysmal occlusion. These findings suggest that SFD is an effective and safe alternative in the endovascular treatment of complex aneurysms.

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