scholarly journals Filament inadequate wall apposition of the different ends of flow diverters in the abdominal aorta of rabbits

2019 ◽  
Vol 33 (1) ◽  
pp. 32-38
Author(s):  
Kuizhong Wang ◽  
Peng Jin ◽  
Peigang Lu ◽  
Qiang Liu ◽  
Bo Li ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Stent Insertion ◽  
Digital Subtraction ◽  
Arterial Diameter ◽  
Significant Difference ◽  
Pathological Evaluation ◽  
Wall Apposition ◽  
Flow Diverters

Background Flow diverters (FDs) with flared ends (FEs) or straight ends (SEs) are used either alone or when overlapped to treat complex intracranial aneurysms. We evaluated filament inadequate wall apposition (IWA) of the FEs and SEs of FDs in vivo. Methods A total of 24 FDs with FEs and SEs were placed in an overlapping manner in the abdominal aortae of six rabbits (two sets per rabbit). Digital subtraction angiography was performed immediately after stent insertion and three months later. The anatomical and histopathological aortic features at FEs and SEs were evaluated. Results Angiography revealed no significant difference in terms of changes in arterial diameter between the FE and SE groups ( p = 0.877). Gross anatomical evaluation revealed IWA of the different ends of FDs but no thrombi or bleeding, showing that the metallic filaments were not in touch with the vessel wall and nor had they penetrated the vessel wall. The filaments’ IWA rates of FEs and SEs were 8.33% and 8.85%, respectively. The IWA rate at overlapping ends was lower than that at non-overlapping ends. The maximum neo-intimal thickness at FEs was greater than that at SEs (149.4 ± 48.9 and 98.6 ± 26.6 µm, respectively; p < 0.001). Conclusions Both the FEs and SEs of FDs can exhibit IMA. IWA events are reduced at the overlapped regions. On pathological evaluation, FEs increased neo-intimal thicknesses more than SEs did, but hyperplasia was minimal on angiography.

Use of flow-diverting stents as salvage treatment following failed stent-assisted embolization of intracranial aneurysms

2015 ◽  
Vol 8 (7) ◽  
pp. 692-695 ◽  
Author(s):  
Daniel M Heiferman ◽  
Joshua T Billingsley ◽  
Manish K Kasliwal ◽  
Andrew K Johnson ◽  
Kiffon M Keigher ◽  
...  
Keyword(s):  
Blood Flow ◽  
Intracranial Aneurysms ◽  
Cerebral Aneurysms ◽  
Flow Diverter ◽  
Salvage Treatment ◽  
Endovascular Techniques ◽  
Pipeline Embolization Device ◽  
Wall Apposition ◽  
Flow Diverters

Flow-diverting stents, including the Pipeline embolization device (PED) and Silk, have been beneficial in the treatment of aneurysms previously unable to be approached via endovascular techniques. Recurrent aneurysms for which stent-assisted embolization has failed are a therapeutic challenge, given the existing intraluminal construct with continued blood flow into the aneurysm. We report our experience using flow-diverting stents in the repair of 25 aneurysms for which stent-assisted embolization had failed. Nineteen (76%) of these aneurysms at the 12-month follow-up showed improved Raymond class occlusion, with 38% being completely occluded, and all aneurysms demonstrated decreased filling. One patient developed a moderate permanent neurologic deficit. Appropriate stent sizing, proximal and distal construct coverage, and preventing flow diverter deployment between the previously deployed stent struts are important considerations to ensure wall apposition and prevention of endoleak. Flow diverters are shown to be a reasonable option for treating previously stented recurrent cerebral aneurysms.

Comparative Hemorheological and Biochemical Studies of a Bovine Fibrinogen

1975 ◽  
Author(s):  
A. L. Copley ◽  
R. G. King ◽  
B. Blombäck
Keyword(s):  
Vessel Wall ◽  
Biochemical Characterization ◽  
Vascular System ◽  
Thrombus Formation ◽  
Chain Structure ◽  
Naval Research ◽  
Significant Difference ◽  
Biochemical Studies ◽  
Torque Values

Among numerous fibrinogen (Fg) preparations of different mammalian origins (human, bovine, sheep, rabbit, cat) in measurements of viscous resistance -VR- (torque values, τ, dyne, cm) of surface layers (SLs), we found as an exception a bovine Fg, FgSM (Schwarz-Mann, Orangeburg, N.Y. Lot # Y1013), which did not show measurable VR at shear rates (SRs) from 10-3 to 10-1 sec-1 without prior application of high shearing forces (hSF). This led to biochemical characterization, in which FgSM did not exhibit any significant difference in chain structure, as compared with highly purified Fg showing high τ, indicating that a dialysable component in the FgSM was responsible for the inhibition of VR. Our biochemical studies could not detect significant differences between the FgSM and Fg from other sources. A hSF at 1000 sec-1 for 3 min was then applied prior to the rheological tests at low SF from 10-3 to 10-1 sec-1. This procedure always resulted in significant increases in VR of SLs of all Fg preparations, including the FgSM. High shear, which exists at the vessel wall in vivo, is particularly high in the microcirculation and is also augmented in vortex and disturbed flow at sites of branchings, bends and bifurcations in the vascular system. The hSF may contribute to the initiation of thrombus formation due to the proposed progressive adsorption of Fg, layer upon layer, at these sites (Copley, Biorheol. 8, 79, 1971; Microvasc. Res. 8, 192, 1974). A further hypothesis is introduced in which the polymerization sites of the Fg molecule are unfolded by the hSF at the vessel wall, resulting in intravascular polymerization of Fg(Aided in part by Office of Naval Research Contract # N00014-75-C-0222 )

Promoting endothelialization of flow-diverting stents: a review

2020 ◽  
Vol 13 (1) ◽  
pp. 86-90 ◽  
Author(s):  
Kapilan Panchendrabose ◽  
Sandeep Muram ◽  
Alim P Mitha
Keyword(s):  
Intracranial Aneurysms ◽  
Surface Modifications ◽  
Biological Agents ◽  
Stent Insertion ◽  
Stent Design ◽  
Short And Long Term ◽  
Wall Apposition

Intracranial flow-diverting (FD) stents have revolutionized the treatment of intracranial aneurysms in recent years, but complications resulting from failed endothelialization can still occur. Approaches to promote endothelialization are understudied, but hold promise in mitigating both short- and long-term complications associated with FD stent insertion. The aim of this review is to highlight the various features of and modifications that have been made to FD stents in order to expedite endothelialization. More specifically, we focus on how endothelialization can be influenced by the stent design, wall apposition, surface modifications, and the inclusion of biological agents.

scholarly journals Analysis of neointima development in flow diverters using optical coherence tomography imaging

2017 ◽  
Vol 10 (2) ◽  
pp. 162-167 ◽  
Author(s):  
Yoshikazu Matsuda ◽  
Joonho Chung ◽  
Demetrius K Lopes
Keyword(s):  
Optical Coherence Tomography ◽  
Surface Modification ◽  
Thickness Ratio ◽  
Swine Model ◽  
Optical Coherence ◽  
Lumen Area ◽  
Neointimal Thickness ◽  
Significant Difference ◽  
Flow Diverters

BackgroundFlow diverters are used for the treatment of intracranial aneurysms. Surface modification may decrease the thrombogenicity of flow diverters but the details are unknown. Optical coherence tomography (OCT) is an intravascular imaging test with high resolution which identifies neointimal growth over stents. We compared the development of neointima in a flow diverter and stents with and without surface modification in a swine model.MethodsIn this study we implanted four devices (two in each carotid artery) in four pigs. The devices used were the Pipeline Flex embolization device (PED Flex, n=6), PED with Shield technology (PED Shield, n=6), and Solitaire AB (n=4). Serial carotid angiographic and OCT images were obtained on days 0, 7, 14, and 21. The data analyzed included: neointimal area (lumen area − stent area), neointimal ratio ([lumen area − stent area]/stent area), and the neointimal thickness ratio (minimum neointimal thickness/maximum neointimal thickness).ResultsThere was no significant difference in where neointima formation was initiated in relation to the implanted device (distal vs middle vs proximal). The PED Shield had a trend towards earlier endothelial formation at day 7. By day 21 the neointimal ratio was significantly higher for the PED Flex and PED Shield devices than for Solitaire (p<0.05 and p<0.01, respectively). The neointimal thickness ratio was significantly higher with PED Shield than with PED Flex and Solitaire (p<0.05 and p<0.01, respectively).ConclusionsOCT enabled us to follow and compare in vivo the development of neointima over implants. PED Shield showed a similar neointimal volume to PED Flex and more concentric neointima.

In-vivo evaluation of the effect of cyanoacrylate on prosthetic vascular graft infection – does cyanoacrylate increase the severity of infection?

VASA ◽  
2020 ◽  
Vol 49 (4) ◽  
pp. 281-284
Author(s):  
Atıf Yolgosteren ◽  
Gencehan Kumtepe ◽  
Melda Payaslioglu ◽  
Cuneyt Ozakin
Keyword(s):  
Vascular Graft ◽  
Graft Infection ◽  
Vascular Graft Infection ◽  
Group 4 ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Prosthetic Vascular Graft Infection ◽  
Group 1

Summary. Background: Prosthetic vascular graft infection (PVGI) is a complication with high mortality. Cyanoacrylate (CA) is an adhesive which has been used in a number of surgical procedures. In this in-vivo study, we aimed to evaluate the relationship between PVGI and CA. Materials and methods: Thirty-two rats were equally divided into four groups. Pouch was formed on back of rats until deep fascia. In group 1, vascular graft with polyethyleneterephthalate (PET) was placed into pouch. In group 2, MRSA strain with a density of 1 ml 0.5 MacFarland was injected into pouch. In group 3, 1 cm 2 vascular graft with PET piece was placed into pouch and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. In group 4, 1 cm 2 vascular graft with PET piece impregnated with N-butyl cyanoacrylate-based adhesive was placed and MRSA strain with a density of 1 ml 0.5 MacFarland was injected. All rats were scarified in 96th hour, culture samples were taken where intervention was performed and were evaluated microbiologically. Bacteria reproducing in each group were numerically evaluated based on colony-forming unit (CFU/ml) and compared by taking their average. Results: MRSA reproduction of 0 CFU/ml in group 1, of 1410 CFU/ml in group 2, of 180 200 CFU/ml in group 3 and of 625 300 CFU/ml in group 4 was present. A statistically significant difference was present between group 1 and group 4 (p < 0.01), between group 2 and group 4 (p < 0.01), between group 3 and group 4 (p < 0.05). In terms of reproduction, no statistically significant difference was found in group 1, group 2, group 3 in themselves. Conclusions: We observed that the rate of infection increased in the cyanoacyrylate group where cyanoacrylate was used. We think that surgeon should be more careful in using CA in vascular surgery.

The Effects of Heparin and Annexin V on Fibrin Accretion after Injury in the Jugular Veins of Rabbits

1993 ◽  
Vol 69 (03) ◽  
pp. 227-230 ◽  
Author(s):  
J Van Ryn-McKenna ◽  
H Merk ◽  
T H Müller ◽  
M R Buchanan ◽  
W G Eisert
Keyword(s):  
Vessel Wall ◽  
Thrombin Generation ◽  
Antithrombin Iii ◽  
Specific Effect ◽  
Annexin V ◽  
Inhibitory Effect ◽  
Jugular Veins ◽  
Prothrombinase Complex ◽  
Wall Injury

SummaryWe compared the relative abilities of unfractionated heparin and annexin V to prevent fibrin accretion onto injured jugular veins in vivo. Heparin was used to accelerate the inhibition of thrombin by antithrombin III, and annexin V was used to inhibit the assembly of the prothrombinase complex on phospholipid surfaces, thereby blocking thrombin generation. Rabbit jugular veins were isolated in situ, a 2 cm segment was injured by perfusing it with air, and then blood flow was re-established. Five minutes later, each rabbit was injected with heparin (20 U/kg) or annexin V (0.3 mg/kg) and then with 125I-fibrinogen. The amount of 125I-fibrin accumulation onto each injured vessel wall segment was measured 4 h later. Each injured vessel was completely deendothelialized as a result of the air perfusion as demonstrated by electron microscopy. 125I-fibrin accretion onto the injured jugular veins was enhanced 2.4-fold as compared to the uninjured veins in sham-operated animals. Heparin treatment did not reduce fibrin accretion, whereas, annexin V treatment decreased fibrin accretion by 60%, p <0.05. This latter effect was achieved without sustained circulating anticoagulation. Additional experiments confirmed that the inhibitory effect of annexin V on fibrin accretion was associated with a surface specific effect, since more annexin V bound to the injured jugular vein segments as compared to the non-injured jugular veins. We conclude that, i) mild vessel wall injury (selective de-endothelialization) in veins results in a thrombogenic vessel wall; ii) the thrombogenecity of which is not inhibited by prophylactic doses of heparin; but iii) is inhibited by annexin V, which binds to injured vessel wall surface, and inhibits thrombin generation independently of antithrombin III.

An Electron Microscopic Study of Platelet Thrombus Formation in the Rabbit with Particular Regard to 5-Hydroxytryptamine Release

1967 ◽  
Vol 18 (03/04) ◽  
pp. 592-604 ◽  
Author(s):  
H. R Baumgartner ◽  
J. P Tranzer ◽  
A Studer
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Vessel Wall ◽  
Thrombus Formation ◽  
Endothelial Damage ◽  
Electron Microscopic ◽  
Rabbit Ear ◽  
Basement Lamina ◽  
Platelet Thrombus

SummaryElectron microscopic and histologic examination of rabbit ear vein segments 4 and 30 min after slight endothelial damage have yielded the following findings :1. Platelets do not adhere to damaged endothelial cells.2. If the vessel wall is denuded of the whole endothelial cell, platelets adhere to the intimai basement lamina as do endothelial cells.3. The distance between adherent platelets as well as endothelial cells and intimai basement lamina measures 10 to 20 mµ, whereas the distance between aggregated platelets is 30 to 60 mµ.4. 5-hydroxytryptamine (5-HT) is released from platelets during viscous metamorphosis at least in part as 5-HT organelles.It should be noted that the presence of collagen fibers is not necessary for platelet thrombus formation in vivo.

In-vivo anti-oxidant screening of Tectona grandis extract

2020 ◽  
Vol 9 (1) ◽  
pp. 1-4
Author(s):  
Tamilarasi G P ◽  
Sabarees G
Keyword(s):  
Biochemical Parameters ◽  
Tectona Grandis ◽  
The Body ◽  
Altered Expression ◽  
Physiological Conditions ◽  
Synthetic Drugs ◽  
Significant Difference ◽  
Anti Oxidant ◽  
Radical Generation

Oxidation is an essential reaction in the human body, which determines the expression of proteins in the body. This results in the altered expression like rapid growth resulting in cancers and other disorders. Many synthetic drugs are available in the market that is effective in limiting the free radical generation and the reaction of radicals with cells. Unfortunately, all those synthetic drugs were found to cause side effects and adverse effects in the body. But given the accuracy of the predictability of the results and administration, this research focuses on testing the anti-oxidant efficiency in rat models testing the biochemical parameters. Investigations have also been done on the anti-oxidant activity of Tectona, but every research was concentrated to prove the anti-oxidant activity only. extract had been tested for anti-oxidant activity by estimating various tissue parameters and it showed better activity. As predicted, there is a significant difference in the and results which can be explained are due to the physiological conditions that exist inside the body.

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