Intra-aneurysmal thrombosis as a possible cause of delayed aneurysm rupture after flow-diversion treatment.
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ABSTRACT: Background and purpose
FD technology enables reconstructive repair of otherwise difficult-to-treat intracranial aneurysms. These stentlike devices may induce progressive aneurysm thrombosis without additional implants and may initiate complete reverse vessel remodeling. The associated vascular biologic processes are as yet only partially understood.Materials and methods
From 12 different centers, 13 cases of delayed postprocedural aneurysm rupture were recorded and analyzed. Symptom, aneurysm location and morphology, and the time elapsed from treatment until rupture were analyzed.Results
There were 10 internal carotid and 3 basilar artery aneurysms. Mean aneurysm diameter was 22 ± 6 mm. Eleven patients were symptomatic before treatment. A single FD was used for all saccular aneurysms, while fusiform lesions were treated by using multiple devices. A supplementary loose coiling of the aneurysm was performed in 1 patient only. Ten patients developed early aneurysm rupture after FD treatment (mean, 16 days; range, 2-48 days); in 3 patients, rupture occurred 3-5 months after treatment. In all cases, most of the aneurysm cavity was thrombosed before rupture. The biologic mechanisms predisposing to rupture under these conditions are reviewed and discussedConclusions
FDs alone may modify hemodynamics in ways that induce extensive aneurysm thrombosis. Under specific conditions, however, instead of reverse remodeling and cicatrization, aggressive thrombus-associated autolysis of the aneurysm wall may result in delayed rupture.
SUBMITTER: Kulcsar Z
PROVIDER: S-EPMC7964960 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Endovascular treatment of intracranial aneurysms with complex morphologies such as giant, wide-necked, or fusiform aneurysms is challenging. Stent-assisted coiling and balloon-assisted coiling are alternative techniques to treat such complex aneurysms, but studies have shown less-than-expected efficacy, as suggested by their high rate of recanalization. The management of complex aneurysms via microsurgery or conventional neuroendovascular strategies has traditionally been poor. However, over the last few years, flow-diverting stents (FDS) have revolutionized the treatment of such aneurysms. FDS are implanted within the parent artery rather than the aneurysm sac. By modifying intra-aneurysmal and parent-vessel flow dynamics at the aneurysm/parent vessel interface, FDS trigger a cascade of gradual intra-aneurysmal thrombosis. As endothelialization of the FDS is complete, the parent vessel reconstructs while preserving the patency of normal perforators and side branch vessels. As with any intervention, the practice and application of flow-diversion technology is inherent, with risks that include vessel rupture or perforation, in-stent thrombosis, perforator occlusion, procedural and delayed hemorrhages, and perianeurysmal edema. Herein, we review the devices, their mechanisms of actions, clinical applications, complications, and ongoing studies.
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Project description:Background and purposeHemodynamics is an important factor in the development and rupture of cerebral aneurysms. Current techniques for measuring blood flow in cerebral aneurysms suffer from various limitations and have not been able to address our clinical needs. A new technique has been developed for effective evaluation of intra-aneurysmal flow based on high-frame-rate cerebral angiography, especially for flow-diverters.Materials and methodsSix patients with 7 unruptured ICA aneurysms were imaged with a specially designed DSA protocol (a 3D DSA and a 2D DSA acquired at 30 frames/s, with a 2-mL/s contrast injection rate). Images of these cases were analyzed to determine the intra-aneurysmal flow based on the newly developed technique. Patient-specific aneurysm models were used for CFD calculation, and intra-aneurysmal flow rates were computed numerically. The intra-aneurysmal flow rates from the 2 methods were then compared.ResultsThere is a linear relationship between intra-aneurysmal flow ratios obtained from high-frame-rate cerebral angiography and CFD calculation (R = 0.99). A high frame rate (30 frames/s) provides a better estimate of intra-aneurysmal flow than low frame rates (7.5 frames/s and 15 frames/s).ConclusionsThe CFD calculation validates the estimate of intra-aneurysmal hemodynamics from cerebral angiography. The linear relationship obtained by using these 2 techniques can be used for real-time assessment of intra-aneurysmal hemodynamics for cerebral aneurysms.
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Project description:Background and purposeFlow diversion with intermediate-porosity stents (braided stents) has been recently reported for distally located small aneurysms. The aim of this study was to evaluate the flow-diversion effect of LEO stents on covered vessels and for aneurysms treated with sole stent-placement therapy.Materials and methodsWe retrospectively evaluated the following outcomes: 1) remodeling of covered side branches and perforators (extra-aneurysmal flow remodeling), and 2) the occlusion rate of aneurysms treated with sole stent-placement therapy (intra-aneurysmal flow remodeling).ResultsSeventy-six patients with 98 covered vessels were studied. Overall, 89 covered arteries (91%) were normal, 7 showed narrowing (7%), and 2 (2%) were occluded (1 posterior communicating artery and 1 MCA) without related complications (mean DSA follow-up, 14 months). Univariate and multivariate analyses highlighted smoking (P = .03) and the length of follow-up (P = .002) as factors associated with arterial remodeling. Of the 17 Sylvian (lenticulostriate arteries) and 7 basilar perforators, 1 (4%) group of Sylvian perforators covered with double stents had asymptomatic remodeling. Ten aneurysms (mean size, 3.5 mm) were treated with LEO stents as stent monotherapy (5 recanalized after coiling and 5 directly treated with the LEO). Complete occlusion (Raymond-Roy I) was achieved in 70% of aneurysms (mean follow-up, 14 months). The Raymond-Roy I occlusion rate among recanalized aneurysms and those directly treated with LEO stents was 80% and 60%, respectively (P = .9).ConclusionsThe rate of flow remodeling on the covered arteries and perforators was 9% and 4%, respectively, and was clinically irrelevant in all cases. Complete occlusion of aneurysms treated with sole stent-placement therapy was 70%. These data stress the flow-diversion properties of LEO stents.
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Project description:Background and purposeRabbit 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.Materials and methodsWith a surgical approach that included elastase infusion and balloon dilation, we attempted the creation of complex fusiform aneurysms in 16 rabbits, with standard saccular carotid aneurysms created in 15 other animals. Aneurysms were randomly allocated to one of the following treatments: flow diversion (n = 8), high-porosity stent (n = 6), double high-porosity stent (n = 5), and control (n = 6). Angiographic assessment and pathologic analyses were performed at 3 months.ResultsCreation of complex fusiform and standard saccular aneurysms was successful in 12/16 and 13/15 attempts, respectively. All saccular (n = 4) or complex fusiform (n = 4) aneurysms treated with flow diverters were successfully occluded. Three of 3 saccular compared with 0/2 complex fusiform aneurysms were occluded by double high-porosity stents. One of 3 saccular and 0/3 complex fusiform aneurysms were occluded by a single high-porosity stent. Both aneurysm types shared the same pathologic findings when untreated: The aneurysm wall lacked an elastic layer and smooth muscle cells, while the lumen was lined with neointima of varying thickness. Neointimal coverage of the devices was complete when aneurysms were occluded, while leaks were always associated with aneurysm remnants.ConclusionsChallenging fusiform aneurysms can be created in rabbits by using a surgical modification of the elastase method.
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