Morphologic and Hemodynamic Changes after Stent Placement for Experimental Carotid Aneurysm

Stent assisted coil embolization is useful in treating broad neck aneurysms, and there are many kinds of stents that can be applied in the cerebral artery, however their characteristics are not well known. We investigated and compared morphologic and hemodynamic changes before and after stent placement when several different kinds of stents were applied to experimental aneurysms. Experimental aneurysms in eight pig carotid arteries were used. Stents were placed covering the aneurysm orifice. Five Cordis stents (coil stent), two GFXs (multilink stent), and one Multilink (tube stent) were used in this study. After coil placement, the arteries were perfused with 70% ethanol, the specimens were embedded in polyester plastic resin and thin slices were stained with hematoxylin-eosin. Blood flow in the aneurysm was measured using digital subtraction angiography. The parent artery was stretched in multilink stent (GFX) cases, and was most markedly stretched by use of the tube stent (Multilink). Stent placement with any type of stent decreased intra-aneurysmal blood flow.

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Morphologic and Haemodynamic Changes after Stent Placement for Experimental Carotid Aneurysm

Interventional Neuroradiology ◽

10.1177/15910199040100s126 ◽

2004 ◽

Vol 10 (1_suppl) ◽

pp. 153-154 ◽

Cited By ~ 1

Author(s):

H. Tenjin

Keyword(s):

Blood Flow ◽

Digital Subtraction Angiography ◽

Stent Placement ◽

Carotid Arteries ◽

Parent Artery ◽

Digital Subtraction ◽

Thin Slices ◽

Before And After ◽

Haemodynamic Changes ◽

Plastic Resin

We investigated and compared the morphologic and haemodynamic changes between before and after stent placement when several different kinds of stents were applied to experimental aneurysms. Experimental aneurysms in eight pig carotid arteries were used. Stents were placed covering the aneurysm orifice. Five Cordis stents (coil stent), two GFXs (multilink stent), and one Multilink (tube stent) were used in this study. After stent placement, the arteries were perfused with 70% ethanol, the specimens were embedded in polyester plastic resin and thin slices were stained with hemtoxilin-eosin. Blood flow in the aneurysm was measured using digital subtraction angiography. The parent artery was stretched in multilink stent (GFX) cases, and was most markedly stretched by use of the tube stent (Multilink). Stent placement with any type of stent decreased intra-aneurysmal blood flow.

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Cinematic Angiography for Measurements of Blood Flow in Cerebral Aneurysms With Stents

Volume 2: Fora, Parts A and B ◽

10.1115/fedsm2007-37254 ◽

2007 ◽

Author(s):

Makoto Ohta ◽

Naoko Fujimura ◽

Luca Augsburger ◽

Hasan Yilmaz ◽

Daniel A. Ru¨fenacht

Keyword(s):

Blood Flow ◽

High Speed ◽

Cerebral Aneurysms ◽

Flow Speed ◽

Circulation System ◽

Parent Artery ◽

Vortex Center ◽

System A ◽

Before And After ◽

Movement Distance

Background and Purpose: The assessment of blood flow speed by imaging modalities is important for endovascular treatments, such as stent implantation, of cerebral aneurysms. The subtracted vortex centers path line method (SVC method) is one of the ways of determining flow speed quantitatively using the image sequence. And a cinematic angiography (CA) is a high speed image acquisition system using X-ray and contrast media integrated in Digital Subtraction Angiography (DSA) for endovascular therapy. The combination of SVC and CA may useful for determining the blood flow speed during the operation using DSA. In this study, we applied this combination to analyze hemodynamic changes before and after stenting. Methods: A transparent tubular model was constructed of silicone which included an aneurysm 10 mm in diameter and having a 5 mm neck on a straight parent artery with a diameter of 3.5 mm. The model was integrated into a pulsatile circulation system. A double layer stent was placed in the parent artery on the aneurysm. By CA, successive images at 25 frames per second with injection of contrast were obtained. Results and conclusion: Rotating vortexes of contrast, which advanced along the wall of the aneurysm, were observed in successive images of the aneurysm cavity. The movement distance of the vortex center was measured and the results show that the vortex speed decrease after stenting. This indicates the possibility of applying the SVC method to medical imaging equipment for analysis of the flow in aneurysms containing stent.

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Vein-Loaded Stent System to Occlude Wide-Necked Aneurysms

Interventional Neuroradiology ◽

10.1177/15910199980040s122 ◽

1998 ◽

Vol 4 (1_suppl) ◽

pp. 105-108

Author(s):

T. Okamoto ◽

T. Iwakoshi ◽

M. Negoro ◽

S. Miyachi ◽

M. Bundou ◽

...

Keyword(s):

Stent Placement ◽

Carotid Arteries ◽

Anticoagulation Therapy ◽

The Other ◽

Parent Artery ◽

Clinical Use ◽

Complete Occlusion ◽

Stent System ◽

Common Carotid Arteries

We devised a vein-loaded stent system to immediately close the aneurysmal orifice without interrupting the parent arterial flow. Ten experimental wide-necked aneurysms located on canine common carotid arteries were treated with the implantation of a newly modified vein-loaded stent system. After deploying the stent, half of them were managed under administration of 50 mg of ticlopidine hydrochloride per day and the other half followed up without any anticoagulation therapy. Immediately after the stent placement, all aneurysms were completely obliterated with patency of the parent artery in the successfully implanted vessels in both groups. Follow-up angiography one week later disclosed complete occlusion of the aneurysm with patency of the parent artery in 67% (2/3) of the group with ticlopidine, while none of the group without drugs showed patency of the parent artery. The rate of patency of the parent artery was found to be improved by administration of ticlopidine, but was still lower than that of a conventional stent. Further modifications will be needed before clinical use.

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Transcranial doppler sonography in two patients who underwent decompressive craniectomy for traumatic brain swelling: report of two cases

Arquivos de Neuro-Psiquiatria ◽

10.1590/s0004-282x2004000400028 ◽

2004 ◽

Vol 62 (3a) ◽

pp. 715-721 ◽

Cited By ~ 16

Author(s):

Edson Bor-Seng-Shu ◽

Manoel Jacobsen Teixeira ◽

Roberto Hirsch ◽

Almir Ferreira de Andrade ◽

Raul Marino Jr

Keyword(s):

Blood Flow ◽

Decompressive Craniectomy ◽

Transcranial Doppler ◽

Doppler Sonography ◽

Transcranial Doppler Sonography ◽

Brain Swelling ◽

Hemodynamic Changes ◽

Before And After ◽

Intracranial Arteries

The role of decompressive craniectomy in the treatment of severe posttraumatic cerebral swelling remains quite a controversial issue. To the best of our knowledge, there is no study demonstrating the effect of decompressive craniectomy on cerebral blood flow (CBF) velocity by means of transcranial Doppler sonography (TCD). We present two patients who developed traumatic brain swelling and uncontrollable intracranial hypertension with coma and signs of transtentorial herniation. One patient underwent bifrontal, while the second, unilateral, frontotemporoparietal decompressive craniectomy with dural expansion. In both patients, TCD examinations were performed immediately before and after surgery to study the cerebral hemodynamic changes related to the operations. Pre and postoperative TCD examinations demonstrated a significant increase in blood flow velocity in the intracranial arteries in both subjects. In conclusion, our cases suggest that decompressive craniectomy with dural expansion may result in elevation of CBF velocity in patients with massive brain swelling. The increase in CBF velocity appears to occur not only in the decompressed hemisphere, but also on the opposite side.

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Aneurysm pressure measurement before and after placement of a Pipeline stent: feasibility study using a 0.014 inch pressure wire for coronary intervention

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2014-011214 ◽

2014 ◽

Vol 8 (6) ◽

pp. 603-607 ◽

Cited By ~ 11

Author(s):

Satoshi Tateshima ◽

Jesse G Jones ◽

Fernando Mayor Basto ◽

Fernando Vinuela ◽

Gary R Duckwiler

Keyword(s):

Stent Placement ◽

Pressure Measurement ◽

Aneurysm Rupture ◽

Flow Diversion ◽

Parent Artery ◽

Stent Deployment ◽

Early Results ◽

Pressure Wire ◽

Significant Difference ◽

Before And After

Flow-diverting stents have provided a new endovascular capacity to reconstruct an intracranial aneurysm with its diseased parent artery. The results of first-generation flow diversion stents have been encouraging, with even large or giant treated aneurysms achieving complete angiographic occlusion at 12-month follow-up. Numerous clinical reports have described a slow progressive thrombosis pattern and gradual increase in rate of complete aneurysm obliteration over time. Despite promising early results, some complications specific to flow-diverting stents have been encountered. Chief among them is delayed aneurysm rupture. This complication did not emerge with stent-assisted coil embolization of intracranial aneurysms, and the underlying cause has not been established. However, new evidence suggests that persistent, or even increased, aneurysm pressure after stent placement may play a role in some delayed ruptures. We sought to evaluate this phenomenon by measuring intrasaccular pressure before and after stent placement using two different 0.014 inch coronary pressure measurement wires. Two patients with giant internal carotid artery aneurysms treated with flow-diverting stents were evaluated. Before and after stent deployment, intrasaccular aneurysm and systemic arterial pressures were recorded for 60 s and compared. In both cases, intrasaccular pressure measurement with the use of 0.014 inch pressure wire system was feasible; the pressure wires could be pushed out of the microcatheter placed in the aneurysms without friction or unexpected microcatheter motion. Despite successful flow-diverting stent deployment and angiographic flow diversion effects with excellent wall opposition across the aneurysm necks, there was no significant difference between intrasaccular and systemic pressures.

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Abstract W P76: Parent Artery Curvature May Help Determine the Effectiveness of Flow Diverter Treatment

Stroke ◽

10.1161/str.45.suppl_1.wp76 ◽

2014 ◽

Vol 45 (suppl_1) ◽

Author(s):

Brando Dimapasoc ◽

Aichi Chien

Keyword(s):

Blood Flow ◽

Flow Rate ◽

Simulation Analysis ◽

Volume Flow Rate ◽

Volume Flow ◽

Parent Artery ◽

Flow Volume ◽

Aneurysm Neck ◽

Flow Reduction ◽

Before And After

Introduction: Flow diverters (FDs) aim to treat intracranial aneurysms by altering intra-aneurysmal hemodynamics. Reports have suggested aneurysm and parent artery shape may affect flow reduction in FD-treatment. The purpose of this study is to gain insight into the way in which aneurysm shape and parent artery curvature influence the ability of FDs to redirect flow. Hypothesis: Aneurysm dome size and parent artery curvature affect FD-induced flow reduction within an aneurysm. Methods: FD models constructed based on the Pipeline Embolization Device with 35% area coverage, 30 um strand diameter, and 4 mm nominal diameter were implemented for hemodynamic simulation analysis. The flow reduction effects were tested using aneurysm models featuring different dome sizes and parent artery curvatures. Aneurysm blood flow was analyzed before and after FD stenting in regions of the aneurysm neck, body, and dome. Results: We found that aneurysms with higher parent artery curvature had increased systole flow volume entering aneurysms before and after stenting, regardless of aneurysm size, with pre-FD volume flow rates for curvatures of 20 and 30 degrees, respectively, 1.54 and 2.40 times those for 10 degree curvature. Furthermore, FD reduced flow less in aneurysms with higher curvature. For parent artery curvatures of 10, 20, and 30 degrees, overall reductions of flow volume entering the aneurysm were 91.1±0.56%, 88.2±1.2%, and 85.5±0.28%, respectively. 97.2% of models had more flow reduction at the aneurysm dome than neck. Figure 1 shows representative, post-FD flow in 10 and 30 degree parent arteries, with a greater volume flow rate in (b) depicted by denser streamlines. Aneurysm dome size was not found to have a significant effect on volume flow rate. Conclusions: We found that artery curvature may have a large influence on FD flow reduction, indicating that FD may be less effective at reducing blood flow entering aneurysms located within higher curvature arteries.

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ICG Flow 800 technology targeted STA-MCA microvascular bypass for exclusion of deep-seated fusiform MCA aneurysm: 2-dimensional operative video

Neurosurgical Focus: Video ◽

10.3171/2021.10.focvid21183 ◽

2022 ◽

Vol 6 (1) ◽

pp. V14

Keyword(s):

Blood Flow ◽

Open Surgery ◽

Superficial Temporal Artery ◽

Temporal Artery ◽

Digital Subtraction ◽

Bypass Patency ◽

Before And After ◽

Mca Aneurysm ◽

Flow 800 ◽

Temporary Clipping

The authors present the case of an 18-year-old male with a deep-seated left fusiform dissecting M3 aneurysm for which endovascular treatment was not applicable. At the open surgery, they used the less commonly reported FLOW 800 fluorescent indocyanine green (ICG) videoangiography, before and after parental aneurysmal artery temporary clipping, to locate the distal outflow branch of the aneurysm and use it as the recipient artery for a superficial temporal artery–M4 bypass, excluding the aneurysm by clipping the parental artery. Repeated ICG FLOW 800 angiography confirmed bypass patency and adequate blood flow. The aneurysm’s exclusion from circulation was confirmed by digital subtraction angiography postoperatively. The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21183

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Contribution of the straightening effect of the parent artery to decreased recanalization in stent-assisted coiling of large aneurysms

Journal of Neurosurgery ◽

10.3171/2016.9.jns16501 ◽

2017 ◽

Vol 127 (5) ◽

pp. 1063-1069 ◽

Cited By ~ 11

Author(s):

Akira Ishii ◽

Hideo Chihara ◽

Takayuki Kikuchi ◽

Daisuke Arai ◽

Hiroyuki Ikeda ◽

...

Keyword(s):

Digital Subtraction Angiography ◽

Parent Artery ◽

Digital Subtraction ◽

Stent Group ◽

Unruptured Aneurysms ◽

Angle Change ◽

Angular Change ◽

Significant Difference ◽

Before And After ◽

The Difference

OBJECTIVEThe durability of embolization of large aneurysms is enhanced by use of the neck-bridging stent. However, it remains unclear what factors contribute to decreased recanalization. The purpose of this study was to demonstrate the contribution of the straightening effect of the parent artery to the durability of stent-assisted coiling for large aneurysms.METHODSOf the 182 aneurysms treated by embolization since the introduction of the neurovascular stent, 82 consecutive unruptured aneurysms with a diameter greater than 7 mm were selected. There were 52 aneurysms treated with a stent (Group S) and 30 treated without a stent (Group NS). Occlusion status was evaluated 12 months after embolization with digital subtraction angiography. The vascular angle of the parent artery was measured before, immediately after, and 12 months after embolization. The rates of recanalization were compared between Group S and Group NS. In Group S, the rates of recanalization were further compared between those aneurysms with and without a significant angle change.RESULTSThe rate of major recanalization was 9.6% in Group S and 26.7% in Group NS. The volume embolization ratio was 32.6% in Group S and 31.6% in Group NS, with no statistically significant difference. However, the angulation change before and after coiling was significantly higher in Group S (10.6°) than in Group NS (0.9°). The difference in the angulation was more evident 12 months after coiling (19.1° in Group S and 1.5° in Group NS). In Group S, recanalization was found in 14.3% of 35 stented aneurysms without a significant angular change when a significant angular change was defined as more than 20°. In contrast, all 17 aneurysms with ≥ 20° of angular change remained occluded.CONCLUSIONSSignificant angular change of ≥ 20° most likely leads to decreased recanalization following stent-assisted embolization of large aneurysms.

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Hemodynamic effects of a combination of clonidine and propranolol in conscious cirrhotic rats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y89-219 ◽

1989 ◽

Vol 67 (10) ◽

pp. 1369-1372 ◽

Cited By ~ 21

Author(s):

Dominique Roulot ◽

Christophe Gaudin ◽

Alain Braillon ◽

Tatsuya Sekiyama ◽

Yannick Bacq ◽

...

Keyword(s):

Blood Flow ◽

Portal Hypertension ◽

Portal Pressure ◽

Biliary Cirrhosis ◽

Hemodynamic Effects ◽

Hemodynamic Changes ◽

Flow Measurements ◽

Before And After ◽

Radioactive Microsphere Method ◽

Blood Flow Measurements

The hemodynamic effects of the combination of clonidine and propranolol were studied in conscious rats with portal hypertension owing to secondary biliary cirrhosis. Pressure and blood flow measurements (radioactive microsphere method) were performed in three groups of eight rats before and after drug administration. The combined effects of clonidine (2 μg/100 g body wt., i.v.) and propranolol (0.2 mg/min for 10 min) were compared with those observed after administration of either clonidine alone or propranolol alone. The association of clonidine and propranolol induced significant decreases in portal pressure (30%) and portal tributary blood flow (43%), the magnitude of these changes being significantly more marked than that after administration of either clonidine alone (12 and 20%, respectively) or propranolol alone (16 and 17%, respectively). After the combination, no significant change in arterial pressure was observed, but cardiac output significantly decreased and systemic vascular resistance significantly increased. Renal blood flow decreased to a similar extent (40%) in the three groups. These findings indicate that the combination of clonidine and propranolol is more effective for reversing splanchnic hemodynamic changes than clonidine alone or propranolol alone. The additive effects of this association are in agreement with the action of clonidine and propranolol at different levels (central and peripheral) and on different receptors (α and β). It suggests that an increase in sympathetic activity may play a major role in hemodynamic changes observed in experimental cirrhosis.Key words: portal hypertension, cirrhosis, splanchnic blood flow, α2-adrenergic agonist, β-blocker.

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