Hemodynamic Characterization of Geometric Cerebral Aneurysm Templates Treated With Embolic Coils

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Priya Nair ◽  
Brian W. Chong ◽  
Aprinda Indahlastari ◽  
Justin Ryan ◽  
Christopher Workman ◽  
...  
Keyword(s):  
Cerebral Aneurysms ◽  
Physical Models ◽  
General Level ◽  
Minor Role ◽  
Parent Vessel ◽  
Hemodynamic Responses ◽  
Geometric Factors ◽  
Image Velocimetry ◽  
Before And After ◽  
Embolic Coils

Embolic coiling is one of the most effective treatments for cerebral aneurysms (CAs), largely due to the hemodynamic modifications that the treatment effects in the aneurysmal environment. However, coiling can have very different hemodynamic outcomes in aneurysms with different geometries. Previous work in the field of biofluid mechanics has demonstrated on a general level that geometry is a driving factor behind aneurysmal hemodynamics. The goal of this study was to relate two specific geometric factors that describe CAs (i.e., dome size (DS) and parent-vessel contact-angle (PV-CA)) and one factor that describes treatment (i.e., coil packing density (PD)) to three clinically relevant hemodynamic responses (i.e., aneurysmal root-mean-square velocity (Vrms), aneurysmal wall shear stress (WSS), and cross-neck flow (CNF)). Idealized models of basilar tip aneurysms were created in both virtual and physical forms to satisfy two-level multifactorial experimental designs. Steady and pulsatile flow hemodynamics were then evaluated in the virtual models using computational fluid dynamics (CFD) (before and after virtual treatment with finite element (FE) embolic coil models), and hemodynamics were also evaluated in the physical models using particle image velocimetry (PIV) (before and after treatment with actual embolic coils). Results showed that among the factors considered, PD made the greatest contributions to effects on hemodynamic responses in and around the aneurysmal sac (i.e., Vrms and WSS), while DS made the greatest contributions to effects on hemodynamics at the neck (i.e., CNF). Results also showed that while a geometric factor (e.g., PV-CA) may play a relatively minor role in dictating hemodynamics in the untreated case, the same factor can play a much greater role after coiling. We consider the significance of these findings in the context of aneurysmal recurrence and rupture, and explore potential roles for the proposed methods in endovascular treatment planning.

Influence of Stent Design on Intraaneurysmal Flow: A PIV Study

2000 ◽  
Author(s):  
V. Livescu ◽  
B. B. Lieber ◽  
L. N. Hopkins ◽  
A. K. Wakhloo
Keyword(s):  
Cardiac Cycle ◽  
Cerebral Arteries ◽  
Temporal Distribution ◽  
Surface Integral ◽  
Parent Vessel ◽  
Image Velocimetry ◽  
Before And After ◽  
The Mean ◽  
Aneurysmal Neck ◽  
Mean Circulation

Abstract Interaction between stents and flow inside a sidewall aneurysm model was investigated using Particle Image Velocimetry (PIV). Three spring-like stents having the same porosity but different filament diameter were placed inside the parent vessel that harbored the aneurysm traversing the aneurysmal neck. The flow field inside the aneurysm was investigated before and after placement of the stents. The flow through model was pulsatile and the hemodynamic conditions were representative for those found in human intracranial and extracranial cerebral arteries. Flow patterns inside the aneurysm were significantly altered after stent placement. To facilitate comparison among all cases, the circulation inside the aneurysm was obtained as the surface integral of the distributed vorticity. The results show that the strength of the circulation is substantially diminished for all stented cases. However, the temporal distribution of the circulation through the cardiac cycle is similar for the three stents considered. Further, the mean circulation over one cardiac cycle was obtained for each case as the integral of the absolute value of the temporal distribution. The mean circulation reveals that noteworthy differences in intraaneurysmal hemodynamics do exist among the filament diameters considered.

scholarly journals Hemodynamic Responses in Lower Limb Lymphedema Patients Undergoing Physical Therapy

Biology ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 642
Author(s):  
Bianca Brix ◽  
Olivier White ◽  
Christian Ure ◽  
Gert Apich ◽  
Paul Simon ◽  
...  
Keyword(s):  
Physical Therapy ◽  
Lymphatic System ◽  
Orthostatic Intolerance ◽  
Hemodynamic Responses ◽  
Stand Test ◽  
Beneficial Effects ◽  
Sit To Stand ◽  
Complete Decongestive Therapy ◽  
Before And After ◽  
Baseline Values

Background: Lymphedema arises due to a malfunction of the lymphatic system, leading to extensive tissue swelling. Complete decongestive therapy (CDT), which is a physical therapy lasting for 3 weeks and includes manual lymphatic drainages (MLD), leads to fluid mobilization and increases in plasma volume. Here, we investigated hemodynamic responses induced by these fluid shifts due to CDT and MLD. Methods: Hemodynamic parameters were assessed continuously during a sit-to-stand test (5 min baseline, 5 min of standing, and 5 min of recovery). This intervention was repeated on days 1, 2, 7, 14, and 21 of CDT, before and after MLD. Volume regulatory hormones were assessed in plasma samples. Results: A total number of 13 patients took part in this investigation. Resting diastolic blood pressure significantly decreased over three weeks of CDT (p = 0.048). No changes in baseline values were shown due to MLD. However, MLD led to a significant decrease in heart rate during orthostatic loading over all epochs on therapy day 14, as well as day 21. Volume regulatory hormones did not show changes over lymphedema therapy. Conclusion: We did not observe any signs of orthostatic hypotension at rest, as well as during to CDT, indicating that lymphedema patients do not display an elevated risk of orthostatic intolerance. Although baseline hemodynamics were not affected, MLD has shown to have potential beneficial effects on hemodynamic responses to a sit-to-stand test in patients undergoing lymphedema therapy.

A novel endovascular clip system for the treatment of intracranial aneurysms: technology, concept, and initial experimental results

2008 ◽  
Vol 108 (6) ◽  
pp. 1230-1240 ◽  
Author(s):  
Thomas R. Marotta ◽  
Thorsteinn Gunnarsson ◽  
Ian Penn ◽  
Donald R. Ricci ◽  
Ian Mcdougall ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Delivery System ◽  
Intracranial Aneurysms ◽  
Balloon Catheter ◽  
Cerebral Aneurysms ◽  
Histopathological Analysis ◽  
Parent Vessel ◽  
Flow Models ◽  
Aneurysm Neck ◽  
Novel Device

Object The authors describe a novel device for the endovascular treatment of intracranial aneurysms, the endovascular clip system (eCLIPs). Descriptions of the device and its delivery system as well as the results of flow model tests and the treatment of experimental aneurysms are provided. Methods The eCLIPs comprises a flexible hybrid implantable device (an anchor and a covered leaf) and a balloon catheter delivery system, designed to be positioned and activated in the parent vessel in such a way that the covered portion will abut the aneurysm neck. The eCLIPs was subjected to testing in glass, elastomeric, and cadaveric flow models to determine its navigability, orientation, and activation compared with commercially available stents. In a second experiment, 8 carotid artery sidewall aneurysms in swine were treated using eCLIPs. The degree of occlusion was observed on angiography immediately following and 30 days after device activation, and a histological analysis was performed at 30 days. Results The device could navigate tortuous glass models and human cadaveric vessels. Compared with commercially available stents, the eCLIPs performed well. It could be navigated, oriented, and activated easily and reliably. With regard to the 8 porcine experimental aneurysms, immediate postactivation angiograms confirmed complete occlusion of 4 lesions and near occlusion of the other 4. Angiographic follow-up at 30 days postactivation showed occlusion of all 8 aneurysms and patency of all parent vessels. Histopathological analysis revealed aneurysm healing, with smooth-muscle cells growing across the lesion neck to allow reendothelialization. Conclusions Aneurysm occlusion with a single extrasaccular endovascular device has potential advantages. The authors believe that eCLIPs may prove to be a useful tool in the endovascular treatment of cerebral aneurysms. The system should reduce risks associated with coiling, procedure time, costs, and radiation exposure. The device satisfactorily occluded 8 experimental sidewall aneurysms. The observed healing pattern is similar to that seen after microsurgical clipping.

Abstract WP33: Early Lessons Learned From the WEB Device: Feasibility, Technique and Complications—A Real Life Experience

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Nikolaos Mouchtouris ◽  
David Hasan ◽  
Fadi Al Saiegh ◽  
Ahmad Sweid ◽  
Mario Zanaty ◽  
...  
Keyword(s):  
Real Life ◽  
Cerebral Aneurysms ◽  
High Volume ◽  
Additional Treatment ◽  
Lessons Learned ◽  
Parent Vessel ◽  
Aneurysm Embolization ◽  
Web Device ◽  
Wide Neck ◽  
The Web

Introduction: Wide-neck bifurcation cerebral aneurysms have always posed a treatment challenge and have historically required either clip ligation, or stent vs. balloon-assisted coil embolization. This predicament led to the development of the newly FDA-approved Woven EndoBridge (WEB) aneurysm embolization system (Sequent Medical Inc, Aliso Viejo, CA) Which is a self-expanding mesh that achieves intrasaccular flow disruption and does not require antithrombotic medications. In this study, we report our experience with the first 64 consecutive aneurysms treated via WEB embolization at two high-volume institutions. Methods: We reviewed our first 61 consecutive patients with 64 cerebral aneurysms who underwent WEB embolization from February-August 2019. We collected data on patient demographics and clinical presentation, aneurysm characteristics, device and procedural details, and functional outcomes. Results: A total of 64 aneurysms were included in our study. Fifteen patients (24.1%) presented with acutely ruptured aneurysm while the rest were unruptured. The majority of patients (82.8%) required only one attempt for successful device deployment, while a stent was necessary as an adjunct treatment in 4 patients (6.3%) due to WEB herniation. Two patients had residual aneurysm that had to undergo additional treatment; one of them underwent second WEB embolization and one underwent clip ligation. One patient with a PICA aneurysm had device dislodgment with injury to the parent vessel—Onyx and coils were used to deconstruct the vertebral artery. Conclusions: The advent of the WEB device has significantly impacted the surgical decision-making for the treatment of bifurcation, wide-neck aneurysms. We discuss in detail the lessons learned from patient selection, device size selection, technique, and complications from two institutions with high-volume endovascular and microsurgical aneurysm treatment experience.

scholarly journals The importance of information upon applying IFRS in financial entities that trade at the Colombian stock market

2019 ◽  
Vol 21 (34) ◽  
pp. 137-152
Author(s):  
Miguel Angel Laverde Sarmiento ◽  
Jorge Fernando Garcia Carrillo ◽  
Juan Carlos Lezama Palomino ◽  
Alejandra Patiño Jacinto
Keyword(s):  
Financial Reporting ◽  
Stock Price ◽  
Stock Exchange ◽  
Regulatory Framework ◽  
General Level ◽  
Market Exchange ◽  
Generally Accepted Accounting Principles ◽  
Financial Reporting Standards ◽  
Before And After ◽  
The Impact

The aim of this research is to determine whether the implementation of the International Financial Reporting Standards (IFRS) in the companies of the financial sector listed on the Colombian Stock Exchange has greater relevance compared to the previous accounting regulatory framework known as Generally Accepted Accounting Principles (GAAP) in Colombia, for the years 2009 to 2016. Taking into account the concept of valorative relevance that indicates that the accounting information is relevant if it affects the stock price reflected in the capital market exchange. To determine this relationship, an adaptation of the model proposed by Ohlson (1995) is used, because it is the most frequently used to measure relevance. The modifications made to the model were to include accounting variables of financial instruments of assets and liabilities to better measure the impact of the IFRS. On a general level, the conclusion is reached that the valorative relevance of financial companies listed on the stock exchange between 2009 and 2016, does not change due to the application of the IFRS. The results are because the regulation that financial companies that are listed on the stock exchange of Colombia are subject to has contributed to the relevance being maintained before and after the application of the new regulatory framework. however, when carrying out the study of the information taking into account only the variables and taking into account the regulations under the IFRS, they present a greater degree of significance.

scholarly journals The influence of temporary occlusion of parent vessel on outcome of surgical treatment of ruptured cerebral aneurysms

2020 ◽  
Vol 77 (11) ◽  
pp. 1142-1145
Author(s):  
Vesna Nikolov ◽  
Misa Radisavljevic ◽  
Boban Jelenkovic ◽  
Marija Andjelkovic-Apostolovic
Keyword(s):  
Surgical Treatment ◽  
Cerebral Aneurysms ◽  
Aneurysm Rupture ◽  
Neurological Deficits ◽  
Grading System ◽  
Parent Vessel ◽  
Current Topic ◽  
Temporary Occlusion ◽  
A Prospective Study ◽  
Temporary Clipping

Background/Aim. Aneurysm rupture followed by sub-arachnoid or intracerebral haemorrhage is always current topic and poses a great challenge to neurosurgeons. The aim of the study was to establish whether applying temporary occlusion before placing a final clip was justified. Methods. A prospective study was conducted on patients with aneurysm rupture, treated at Neurosurgical Clinic in Nis from January 2012 to December 2016. Patients belonging to I and II and 1, 2 and 3 grades according to the Hunt-Hess grading system and Fisher scale, respectively, were monitored. Results. In 85, out of total 182 bleeding aneurysms that were treated, a neurosurgeon decided to apply temporary clipping before placing the final clip. Temporary occlusion significantly influenced the presence of resulting neuro-logical deficit. Conclusion. The application of temporary occlusion facilitates placing the final clip but also affects the occurrence of neurological deficits. It is assumed that this is a consequence of caused vasospasm, considering that these are bleeding aneurysms.

Endothelin antagonist reduces hemodynamic responses to vasopressin in DOCA-salt hypertension

2001 ◽  
Vol 281 (6) ◽  
pp. H2511-H2517 ◽  
Author(s):  
Ming Yu ◽  
Venkat Gopalakrishnan ◽  
Thomas W. Wilson ◽  
J. Robert McNeill
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Angiotensin Ii ◽  
Total Peripheral Resistance ◽  
Peripheral Resistance ◽  
Hemodynamic Responses ◽  
Hypertensive Group ◽  
Time Flow ◽  
Before And After ◽  
Vascular Responsiveness

The contribution of endothelin to the changes in blood pressure, cardiac output, and total peripheral resistance evoked by arginine vasopressin and angiotensin II was investigated in deoxycorticosterone acetate (DOCA)-salt hypertensive rats by infusing the peptides intravenously before and after pretreatment with the endothelin receptor antagonist bosentan. Blood pressure was recorded with radiotelemetry devices and cardiac output was recorded with ultrasonic transit time flow probes in conscious unrestrained animals. The dose-related decreases in cardiac output induced by vasopressin and angiotensin II were unaffected by bosentan. In contrast, the dose-related increases in total peripheral resistance evoked by vasopressin were blunted in both DOCA-salt hypertensive and sham normotensive rats, but this effect of bosentan was greater in the DOCA-salt hypertensive group. In contrast with vasopressin, bosentan failed to change hemodynamic responses to angiotensin II. The exaggerated vascular responsiveness (total peripheral resistance) of the DOCA-salt hypertensive group to vasopressin was largely abolished by bosentan. These results suggest that endothelin contributes to the hemodynamic effects of vasopressin but not angiotensin II in the DOCA-salt model of hypertension.

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.

scholarly journals Rescue Therapy for Procedural Complications Associated With Deployment of Flow-Diverting Devices in Cerebral Aneurysms

2018 ◽  
Vol 15 (6) ◽  
pp. 624-633 ◽  
Author(s):  
Fawaz Al-Mufti ◽  
Krishna Amuluru ◽  
Eric R Cohen ◽  
Vikas Patel ◽  
Mohammad El-Ghanem ◽  
...  
Keyword(s):  
Rescue Therapy ◽  
Significant Risk ◽  
Cerebral Aneurysms ◽  
Flow Diverter ◽  
Side Branch ◽  
Parent Vessel ◽  
Vessel Injury ◽  
Procedural Complications ◽  
Background Material ◽  
Device Deployment

Abstract Flow diverting devices (FDDs) have revolutionized the treatment of morphologically complex intracranial aneurysms such as wide-necked, giant, or fusiform aneurysms. Although FDDs are extremely effective, they carry a small yet significant risk of intraprocedural complications. As the implementation of these devices increases, the ability to predict and rapidly treat complications, especially those that are iatrogenic or intraprocedural in nature, is becoming increasingly more necessary. Our objective in this paper is to provide a descriptive summary of the various types of intraprocedural complications that may occur during FDDs deployment and how they may best be treated. A systematic and qualitative review of the literature was conducted using electronic databases MEDLINE and Google Scholar. Searches consisted of Boolean operators “AND” and “OR” for the following terms in different combinations: “aneurysm,” “endovascular,” “flow diverter,” “intracranial,” and “pipeline.” A total of 94 papers were included in our analysis; approximately 87 of these papers dealt with periprocedural endovascular (mainly related to FDDs) complications and their treatment; 7 studies concerned background material. The main categories of periprocedural complications encountered during deployment of FDDs are failure of occlusion, parent vessel injury and/or rupture, spontaneous intraparenchymal hemorrhage, migration or malposition of the FDDs, thromboembolic or ischemic events, and side branch occlusion Periprocedural complications occur mainly due to thromboembolic events or mechanical issues related to device deployment and placement. With increasing use and expanding versatility of FDDs, the understanding of these complications is vital in order to effectively manage such situations in a timely manner.

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

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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