Resolution of mass effect and compression symptoms following endoluminal flow diversion for the treatment of intracranial aneurysms.

BACKGROUND AND PURPOSE: Alleviation of aneurysm induced mass effect has been difficult with both conventional endovascular and surgical techniques. Our aim was to study the efficacy of endovascular flow modification on aneurysm-induced mass effect and compression syndrome, as demonstrated by cross-sectional imaging studies and clinical follow-up. MATERIALS AND METHODS: Thirty aneurysms larger than 10 mm were treated by flow diversion alone and previously had undergone pre- and posttreatment cross-sectional imaging. Pretreatment MR imaging or contrast CT, follow-up angiography at 6 months, and follow-up MR imaging studies between 6 and 18 months were retrospectively analyzed. The neurologic and neuro-ophthalmologic statuses of all patients were recorded before treatment and at the time of follow-up cross-sectional imaging. RESULTS: At 6 months, 28 aneurysms were completely occluded, 1 had a neck remnant, and 1 had residual filling on angiography. Between 6 and 18 months, 3 aneurysms decreased in size and 27 completely collapsed as demonstrated on MR imaging. Before treatment, 6 patients had vision loss, 10 had double vision due to a third or sixth nerve palsy or both, and 1 had hemiparesis due to brain stem compression. On MR imaging follow-up, vision loss had either improved or resolved in all except 1 patient, double vision had resolved completely (7/10) or partially (3/10), and the patient with brain stem compression became asymptomatic. There was no bleeding observed in this series. One parent artery thrombosis resulted in a major infarct. CONCLUSIONS: Endovascular flow diversion is a highly effective technique for resolving radiologic mass effect and clinical compression syndromes.

Hemodynamics of cerebral aneurysm initiation: the role of wall shear stress and spatial wall shear stress gradient.

BACKGROUND AND PURPOSE: Cerebral aneurysms are preferentially located at arterial curvatures and bifurcations that are exposed to major hemodynamic forces, increasingly implicated in the life cycle of aneurysms. By observing the natural history of aneurysm formation from its preaneurysm state, we aimed to examine the hemodynamic microenvironment related to aneurysm initiation at certain arterial segments later developing an aneurysm. MATERIALS AND METHODS: The 3 patients included in the study underwent cerebral angiography with 3D reconstruction before a true aneurysm developed. The arterial geometries obtained from the 3D-DSA models were used for flow simulation by using finite-volume modeling. The WSS and SWSSG at the site of the future aneurysm and the flow characteristics of the developed aneurysms were analyzed. RESULTS: The analyzed regions of interest demonstrated significantly increased WSS, accompanied by an increased positive SWSSG in the adjacent proximal region. The WSS reached values of >5 times the temporal average values of the parent vessel, whereas the SWSSG approximated or exceeded peaks of 40 Pa/mm in all 3 cases. All patients developed an aneurysm within 2 years, 1 of which ruptured. CONCLUSIONS: The results of this hemodynamic study, in accordance with the clinical follow-up, suggest that the combination of high WSS and high positive SWSSG focused on a small segment of the arterial wall may have a role in the initiation process of aneurysm formation.

Thromboembolic complication induced stable occlusion of a ruptured basilar tip aneurysm. Case report and review of the literature.

We describe a case of a ruptured basilar bifurcation aneurysm that thrombosed during preparation for endovascular therapy as a complication of diagnostic angiogaphy, and showed a favorable evolution during long-term follow-up. Endogenous thrombosis of ruptured, non giant aneurysms is uncommon. The persistence of occlusion over time in such cases is not well established. Two weeks after rupture, a 6 x 8 mm basilar bifurcation aneurysm was referred for endovascular treatment. During preparation for endovascular coil occlusion, without having any endovascular material at the level of the basilar artery, a complete thrombotic occlusion of the basilar bifurcation and aneurysm was observed. Given the good collateral circulation for both posterior cerebral arteries no thrombolysis was undertaken. The early follow-up of seven days, three and six months showed a complete recanalization of the basilar artery and remodeling of the basilar bifurcation. The 20 months imaging follow-up demonstrated a small aneurysm regrowth at the prevoius location that remained stable during the follow-up of seven years. Unchanged biological and hemodynamic characteristics. however, may pose an elevated risk of a new aneurysm formation over time, making long-term imaging follow-up, and in case of progression, aneurysm occlusion necessary for the patient.

Treatment of intracranial aneurysms by functional reconstruction of the parent artery: the Budapest experience with the pipeline embolization device.

BACKGROUND AND PURPOSE: Aneurysm treatment by intrasaccular packing has been associated with a relatively high rate of recurrence. The use of mesh tubes has recently gained traction as an alternative therapy. This article summarizes the midterm results of using an endoluminal sleeve, the PED, in the treatment of aneurysms. MATERIALS AND METHODS: A total of 19 wide-neck aneurysms were treated in 18 patients: 10 by implantation of PEDs alone and 9 by a combination of PED and coils. Angiographic and clinical results were recorded immediately and at 6 months following treatment. RESULTS: Immediate angiographic occlusion was achieved in 4 and flow reduction, in another 15 aneurysms. Angiography at 6 months demonstrated complete occlusion in 17 and partial filling in 1 of 18 patients. There was no difference between coil-packed and unpacked aneurysms. Of 28 side branches covered by > or =1 device, the ophthalmic artery was absent immediately in 1 and at 6 months in another 2 cases. One patient experienced abrupt in-stent thrombosis resulting in a transient neurologic deficit, and 1 patient died due to rupture of a coexisting aneurysm. All giant aneurysms treated with PED alone were demonstrated by follow-up cross-sectional imaging to have involuted by 6 months. CONCLUSIONS: Treatment of large, wide-neck, or otherwise untreatable aneurysms with functional reconstruction of the parent artery may be achieved with relative safety using dedicated flow-modifying devices with or without adjunctive use of intrasaccular coil packing.

The potential of flow modification in the treatment of intracranial aneurysms.

UNLABELLED: Abstract: BACKGROUND AND PURPOSE: To summarize the theoretical background and existing technical achievements of flow modification techniques in the treatment of intracranial aneurysms. The evolution of the concept of flow modification for aneurysm treatment is overviewed within the published literature on application of stents for aneurysms. The newest achievements using dedicated flow modifying devices is discussed. Reconstruction of laminar flow within intracranial arteries harboring aneurysms is feasible. Reorientation of flow using dedicated flow modifying devices is a highly effective technique in the treatment of large, broad neck, otherwise untreatable aneurysms.

Endovascular treatment of intracranial aneurysms with parent vessel reconstruction using balloon and self expandable stents.

BACKGROUND AND PURPOSE: To assess the feasibility and results of parent vessel stent reconstruction with balloon expandable and self-expandable stents in the treatment of intracranial aneurysms. METHODS: In a total of 18 aneurysms balloon expandable (group A) and self expandable (group B) stents were used in 9 cases each. Stent implantation alone was used in 3 cases, and additional coil packing in the other 15. RESULTS: Stents were successfully deployed in 8 out of 9 in group A and in 9 out of 9 cases in group B. Nearly complete occlusion was achieved in all but one case. At 3 or 6 months stable occlusion was found in 4 group A and 2 group B patients, progressive thrombosis in 3 cases in both groups, and recanalisation in 1 case in group B. Late follow up at 1-4 years demonstrated one progressive thrombosis one recanalisation and 1 stable occlusion in 3 group A, and 2 stable occlusions in 2 group B. patients. Complications included one aneurysm perforation in group A, one in-stent thrombosis and a distal arterial perforation in group B and one groin hematoma in both groups. CONCLUSION: Stent reconstruction of intracranial arteries harbouring aneurysms is feasible and may result in aneurysm thrombosis without coil packing in some cases. Self expanding stents seem to provide a higher rate of success. Aggressive antiplatelet treatment increases the risk of hemorrhagic complications.

Histopathologic evaluation of aneurysms treated with Guglielmi detachable coils or matrix detachable microcoils.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the degree of organization and fibrocellular tissue development in aneurysms treated with bare platinum or biologically active microcoils. METHODS: Twelve aneurysms were removed at autopsy between 1-18 days and another 2 between 2-3 months posttreatment. Four aneurysms were surgically removed between 6 months and 3 years following treatment. One aneurysm removed at 8 days and another at 6 months were treated with bioactive (Matrix) coils; the other 16 with bare platinum (Guglielmi detachable coils; GDCs). All specimens were embedded in plastic, stained with hematoxilin-eosin and elastin and examined by light microscopy. RESULTS: All specimens removed within 3 weeks demonstrated intra-aneurysmal thrombus, without signs of organization or fibrotic tissue formation over the neck regardless of the type of coils used. In the GDC-treated aneurysms, evidence of early thrombus organization was observed within 2-3 months, and completed yet imperfect fibrocellular reaction together with residual thrombus at 2-3 years. In the Matrix-treated specimens, the aneurysm cavity was completely filled with granulation tissue corresponding to still ongoing fibrocellular reaction at 6 months, including newly formed blood vessels, smooth muscle cells, and collagen deposition without signs of residual thrombus. CONCLUSIONS: Our results indicate that in aneurysms treated with bare platinum coils thrombus organization does not occur until late after treatment and may remain imperfect for years. In one aneurysm studied 8 days following treatment with Matrix coils, no difference was noted compared to aneurysms treated with bare platinum coils. In another aneurysm examined 6 months following packing with Matrix coils, the histologic changes support the hypothesis that the biologically active polymer may accelerate aneurysm healing.