Comparing N-hexyl cyanoacrylate (Magic Glue) and N-butyl cyanoacrylate (NBCA) for neurovascular embolization using the pressure cooker technique: An experimental study in swine.

Background: The pressure cooker (PC) technique uses a second microcatheter to produce a proximal occlusion to prevent the reflux of liquid embolic agent (LEA) injected through a more distal microcatheter, and can be used to treat arteriovenous malformations and dural arteriovenous fistulae. The liquid embolic Magic Glue (MG) (N-hexyl cyanoacrylate (NHCA)) has been introduced as an alternative to N-butyl cyanoacrylate (NBCA). Our goals were to compare the extent of embolization of rete mirabile with or without the PC technique using NBCA or MG, and to compare the proximal occlusions obtained with MG or NBCA while using the PC technique in a renal arterial model.

Testing the Medina embolization device in experimental aneurysms.

Objective: The Medina embolization device (MED) is a novel, braided self-expanding endovascular device designed to occlude aneurysms by constructing an in situ intrasaccular flow diverter. Although a single device can be positioned at the neck of simple spherical in vitro aneurysms, the best way to occlude more complex in vivo aneurysms (using multiple MEDs or a combination of MEDs and platinum coils) is currently unknown.

Methods: Fifty-two aneurysms of 3 different types were created in 31 canines, yielding 48 patent aneurysms.

Shear wave elasticity imaging for residual endoleak and thrombus characterisation after endoleak embolisation following endovascular aneurysm repair: a canine animal study.

Background: To evaluate residual endoleak and thrombus organisation with shear wave imaging (SWI) after endoleak embolisation through an animal study.

Methods: This prospective experimental study involved eight dogs with creation of 16 iliac aneurysms and type I endoleak after endovascular aneurysm repair (EVAR). Embolisation agents were injected into the sac to seal endoleak.

Re-treatment of residual aneurysms after flow diversion: An experimental study.

Aim Flow diverters are increasingly used to treat aneurysms, but treatment is not always effective. The management of aneurysms that fail to occlude following flow diversion is problematic. We aimed to reproduce failures in an animal model and study re-treatment with additional flow diverters alone or with flow diverters and liquid embolic agent.

Flow diversion: what can clinicians learn from animal models?

Introduction: Flow diversion is increasingly used for treating intracranial aneurysms. This article aims to review the evidence obtained from animal models and summarizes the findings that might be of clinical interest.

Methods: From a systematic review of studies published between 2000 and 2016, we extracted the data on the following questions: What roles do aneurysm dimension, morphology, and vascular geometry have on success of flow diversion? What characteristics of a flow diverter can influence aneurysm occlusion? What are the risk factors for jailed branch occlusion?

Results: Flow diversion has been shown to be less effective in occluding large aneurysms with wide or undefined necks, as compared to smaller aneurysms with narrower necks.

Testing Stenting and Flow Diversion Using a Surgical Elastase-Induced Complex Fusiform Aneurysm Model.

Background And Purpose: Rabbit elastase-induced saccular aneurysms have been commonly used for preclinical testing of endovascular devices, including flow diverters. However, all tested devices have been shown to be capable of aneurysm occlusion with this model. We aimed to create a more challenging model to test and discriminate among neurovascular devices of varying efficacies.

Abdominal aortic aneurysm follow-up by shear wave elasticity imaging after endovascular repair in a canine model.

Objectives: To investigate if shear wave imaging (SWI) can detect endoleaks and characterize thrombus organization in abdominal aortic aneurysms (AAAs) after endovascular aneurysm repair.

Methods: Stent grafts (SGs) were implanted in 18 dogs after surgical creation of type I endoleaks (four AAAs), type II endoleaks (13 AAAs) and no endoleaks (one AAA). Color flow Doppler ultrasonography (DUS) and SWI were performed before SG implantation (baseline), on days 7, 30 and 90 after SG implantation, and on the day of the sacrifice (day 180).

Bipolar radiofrequency ablation of aneurysm remnants after coil embolization can improve endovascular treatment of experimental bifurcation aneurysms.

OBJECTIVE Endovascular treatment of aneurysms may result in incomplete initial occlusion and aneurysm recurrence at angiographic follow-up studies. This study aimed to assess the feasibility and efficacy of bipolar radiofrequency ablation (RFA) of aneurysm remnants after coil embolization. METHODS Bipolar RFA was accomplished using the coil mass as 1 electrode, while the second electrode was a stent placed across the aneurysmal neck.

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

Background: Flow 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.

Fatal arterial rupture during angioplasty of a flow diverter in a recurrent, previously Y-stented giant MCA bifurcation aneurysm.

Background And Purpose: A patient with a previously Y-stented giant left middle cerebral artery (MCA) bifurcation aneurysm returned with a recurrence.

Materials And Methods: A flow diverter (FD) was deployed through one limb of the high-porosity Y-stenting construction. The proximal FD failed to expand and an attempt at balloon angioplasty led to fatal rupture of the MCA.

Testing flow diversion in animal models: a systematic review.

Introduction: Flow diversion (FD) is increasingly used to treat intracranial aneurysms. We sought to systematically review published studies to assess the quality of reporting and summarize the results of FD in various animal models.

Methods: Databases were searched to retrieve all animal studies on FD from 2000 to 2015.

Temporary surgical clipping of flow-diverted arteries in an experimental aneurysm model.

OBJECTIVE Surgical management of recurrent aneurysms following failed flow diversion may pose difficulties in securing vascular control with temporary clips. The authors tested the efficacy and impact of different types of aneurysm clips on flow-diverted arteries. METHODS Six wide-necked experimental aneurysms were created in canines and treated with Pipeline flow diverters.

Endovascular Repair of Abdominal Aortic Aneurysm: Follow-up with Noninvasive Vascular Elastography in a Canine Model.

Purpose: To assess the ability of noninvasive vascular elastography (NIVE) to help characterize endoleaks and thrombus organization in a canine model of abdominal aortic aneurysm after endovascular aneurysm repair with stent-grafts, in comparison with computed tomography (CT) and pathologic examination findings.

Materials And Methods: All protocols were approved by the Animal Care Committee in accordance with the guidelines of the Canadian Council of Animal Care. Stent-grafts were implanted in a group of 18 dogs with aneurysms created in the abdominal aorta.

Compaction of flow diverters improves occlusion of experimental wide-necked aneurysms.

Introduction: Flow diverters (FDs) are increasingly used in the treatment of wide-necked aneurysms.

Objective: To examine the hypothesis that intentional FD compaction might improve aneurysm occlusion rates.

Methods: Bilateral wide-necked carotid aneurysms were created in 12 dogs.

Dual-lumen balloon catheters may improve liquid embolization of vascular malformations: an experimental study in Swine.

Background And Purpose: Liquid embolic agents are increasingly used to treat vascular malformations. We sought to assess embolization with these agents by using a dual-lumen balloon catheter in an experimental setting.

Materials And Methods: Eighteen injections of liquid embolic agents were performed in the rete mirabile of swine.

Flow diverters: inter and intra-rater reliability of porosity and pore density measurements.

Background And Purpose: Porosity and pore density (PD) are important characteristics of flow diverters (FDs), because they may influence device efficacy and safety. Reliable measurement of these parameters would seem to be required for comparisons between devices, device selection at the time of clinical usage, as well as for research purposes. Because there is no standard method of measurement, our aim was to assess the intra-rater and inter-rater reliability of PD measurements and of three different ways of measuring porosity.

Fatal avulsion of choroidal or perforating arteries by guidewires. Case reports, ex vivo experiments, potential mechanisms and prevention.

Innovations in endovascular tools have permitted an increasingly broad range of neurovascular lesions to be treated via minimally invasive methods. However, some device modifications may carry additional risks, not immediately apparent to operators. A patient with a symptomatic, partially thrombosed basilar apex aneurysm was allocated balloon-assisted coiling.

The success of flow diversion in large and giant sidewall aneurysms may depend on the size of the defect in the parent artery.

Background And Purpose: Flow diverters are designed to occlude aneurysms while preserving flow to jailed arterial branches. We postulated that treatment success depended on the size of the aneurysm ostium or defect in the parent artery.

Materials And Methods: Flow diverter expansion and deformation were studied in silicone tubes with wall apertures of various sizes.

Y-crossing of braided stents with stents and flow diverters does not cause significant stenosis in bench-top studies.

Y-stent placement to treat bifurcation aneurysms requires the second device to cross the confines of the first stent, with concerns regarding the formation of stenosis of the second device at the site of crossing. Various braided stents and flow diverters (FDs) were deployed to cross through a high porosity braided stent, in a Y configuration, with the ends of the devices inserted in plastic tubes of various diameters, leaving the mid-portion free to expand. The ensuing constructs were photographed, paying attention to the degree of stenosis, if any, created where the second device crosses the first stent.

In vitro reproduction of device deformation leading to thrombotic complications and failure of flow diversion.

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.

Flow diversion of giant curved sidewall and bifurcation experimental aneurysms with very-low-porosity devices.

Objective: Flow diverters (FDs) are increasingly used to treat difficult intracranial aneurysms. The objective of this study was to test whether treatment challenges posed by giant curved sidewall (cSW) and endwall bifurcation (EwB) aneurysms can be overcome with the use of very-low-porosity devices.

Methods: Large and giant EwB (n = 12) and cSW aneurysms (n = 5) were constructed in 17 dogs.

Endovascular treatment with flow diverters may fail to occlude experimental bifurcation aneurysms.

Introduction: Animal models may explain how stents and flow diverters (FDs) may succeed or fail to treat bifurcation aneurysms.

Methods: In vitro studies were designed to anticipate device deformations in bifurcations. Large, wide-necked bifurcation aneurysms were constructed in 21 animals and treated 4-8 weeks later using stents and FDs in various combinations, forming four main groups: parent artery to right branch flow diversion (RBFD, n = 6), parent artery to left branch flow diversion (LBFD, n = 6), Y flow diversion (YFD, n = 4), and compared with high-porosity Y-stenting (YHPS, n = 4).

Aneurysm rupture after endovascular flow diversion: the possible role of persistent flows through the transition zone associated with device deformation.

Haemorrhagic complications can occur following aneurysm treatment with flow diverters (FD), but the underlying mechanism remains unknown. We describe a case where deformation of the device may have contributed to the complication. A patient with a giant, previously unruptured cavernous aneurysm that extended intracranially to cause oedema of the internal capsule was treated with flow diversion.

Thrombosis heralding aneurysmal rupture: an exploration of potential mechanisms in a novel giant swine aneurysm model.

Background And Purpose: The relationship between aneurysm dimensions, flow, thrombosis, and rupture remains poorly understood. We attempted to clarify this relationship by exploring various swine aneurysm models.

Materials And Methods: Bilateral carotid aneurysms were constructed according to 3 protocols in 24 animals: small aneurysms with wide necks (group 1; n = 6 animals); small aneurysms with small necks (group 2; n = 4 animals), and giant aneurysms with large necks (group 3; n = 14 animals).

Stent-assisted coiling of bifurcation aneurysms may improve endovascular treatment: a critical evaluation in an experimental model.

Background And Purpose: Endovascular treatment of wide-neck bifurcation aneurysms often results in incomplete occlusion or aneurysm recurrence. The goals of this study were to compare results of coil embolization with or without the assistance of self-expandable stents and to examine how stents may influence neointima formation.

Materials And Methods: Wide-neck bifurcation aneurysms were constructed in 24 animals and, after 4-6 weeks, were randomly allocated to 1 of 5 groups: 1) coil embolization using the assistance of 1 braided stent (n = 5); 2) coil embolization using the assistance of 2 braided stents in a Y configuration (n = 5); 3) coil embolization without stent assistance (n = 6); 4) Y-stenting alone (n = 4); and 5) untreated controls (n = 4).