Endovascular strategy for unruptured cerebral aneurysms

Personality change after 'flow diverter implantation' for intracranial aneurysm in a patient with stroke: A case report

OBJECTIVE

This study aimed to present a patient with psychiatric symptoms that occur after flow diverter stent placement in a posterior communicating artery (PComA) aneurysm in a patient.

DESIGN

A case study.

METHOD

We performed cranial magnetic resonance imaging (MRI), magnetic resonance angiography, computed tomography angiography, neuropsychological tests, Levenson Self-Report Psychopathy Scale (LSRP), and a 25-item version of the Wender Utah Rating Scale (WURS-25). The patient's recent MRI was compared with previous MRIs. Neuropsychological testing consisted of a clinical interview, clinical assessment of frontal lobe syndrome, and tests evaluating the prefrontal cortex functions (Wisconsin Card Sorting Test-128 card version and Iowa Gambling Test).

RESULTS

Our results showed that the patient's personality change and psychiatric symptoms occurred after the stent placement. Symptoms were still present at evaluation two and a half years after stent placement.

CONCLUSION

The study demonstrates personality changes and psychiatric symptoms that might occur as complications following the placement of a flow diverter for incidentally detected aneurysm.

Leveraging Patient-Specific Simulated Angiograms to Characterize Cerebral Aneurysm Hemodynamics using Computational Fluid Dynamics

Cerebral aneurysms (CA) affect nearly 6% of the US population and its rupture is one of the major causes of hemorrhagic stroke. Neurointerventionalists performing endovascular therapy (ET) to treat CA rely on qualitative image sequences obtained under fluoroscopy guidance alone, and do not have access to crucial quantitative information regarding blood flow before, during and after treatment - partially contributing to a failure rate of up to 30%. Computational fluid dynamics (CFD) is a powerful tool that can provide a wealth of quantitative data; however, CFD has found limited utility in the clinic due to the challenges in obtaining hemodynamic boundary conditions for each patient. In this work, we present a novel CFD-based simulated angiogram approach (SAA) that resolves the blood flow physics and interaction between blood and injected contrast agent to extract quantitative hemodynamic parameters which can be used to design real-time parametric imaging analysis. The SAA enables correlating contrast agent transport to the underlying hemodynamic conditions via time-density curves (TDC) obtained at several points in the region of interest. The ability of the TDC and the SAA to provide critical hemodynamic parameters in and around CA anatomies, such as washout and local flow changes is explored and presented. This provides invaluable quantitative data to the clinician at the time of intervention, since it incorporates the physics of blood flow and correlates the contrast transport to hemodynamic parameters quantitatively - thereby enabling the clinician to take informed decisions that improve treatment outcomes.

Virtual flow-diverter treatment planning: The effect of device placement on bifurcation aneurysm haemodynamics

Bifurcation aneurysms account for a large fraction of cerebral aneurysms and often present morphologies that render traditional endovascular treatments, such as coiling, challenging and problematic. Flow-diverter stents offer a potentially elegant treatment option for such aneurysms, but clinical use of these devices remains controversial. Specifically, the deployment of a flow-diverter device in a bifurcation entails jailing one or more potentially vital vessels with a low-porosity mesh designed to restrict the flow. When multiple device placement configurations exist, the most appropriate clinical decision becomes increasingly opaque. In this study, three bifurcation aneurysm geometries were virtually treated by flow-diverter device. Each aneurysm was selected to offer two possible device deployment positions. Flow-diverters similar to commercially available designs were deployed with a fast-deployment algorithm before transient and steady state computational fluid dynamics simulations were performed. Reductions in aneurysm inflow, mean wall shear stress and maximum wall shear stress, all factors often linked with aneurysm treatment outcome, were compared for different device configurations in each aneurysm. In each of the three aneurysms modelled, a particular preferential device placement was shown to offer superior performance with the greatest reduction in the flow metrics considered. In all the three aneurysm geometries, substantial variations in inflow reduction (up to 25.3%), mean wall shear stress reduction (up to 14.6%) and maximum wall shear stress reduction (up to 12.1%) were seen, which were all attributed to device placement alone. Optimal device placement was found to be non-trivial and highly aneurysm specific; in only one-third of the simulated geometries, the best overall performance was achieved by deploying a device in the daughter vessel with the highest flow rate. Good correspondence was seen between transient results and steady state computations that offered a significant reduction in simulation run time. If accurate steady state computations are combined with the fast-deployment algorithm used, the modest run time and corresponding hardware make a virtual treatment pipeline in the clinical setting a meaningful possibility.

Outcomes of Stent-assisted Coil Embolization of Wide-necked Intracranial Aneurysms Using the Solitaire™ AB Neurovascular Remodeling Device

Objective

This retrospective study presents our experience with respect to the clinical and angiographic outcomes of patients treated with stent-assisted coil embolization using Solitaire™ AB stents.

Materials and Methods

From March 2011 to December 2014, 50 patients with 55 wide-necked and/or complex intracranial aneurysms were evaluated. Four patients presented with an acute subarachnoid hemorrhage. Stent deployment was performed with a standard coiling procedure in 49 aneurysms. Three patients underwent bailout stenting, 2 patients were treated by temporary stenting and one patient was treated only by stenting without coiling for dissecting aneurysm.

Results

Successful placement of the Solitaire AB stent was achieved in all the cases. Based on the postprocedural angiographic results, a Raymond 1 was obtained in 32 (59%) of 54 aneurysms, excluded by one case of dissecting aneurysm, and a Raymond 2 in 13 (24%), and a Raymond 3 in 9 (17%). There was one thromboembolic (2%) and three hemorrhagic complications (6%). However, procedure-related morbidity or mortality was not found. Annual follow-up angiographic results from the embolization were obtained in 40 (74.1%) of 54 cases. These results were represented as Raymond 1 in 27 (67.5%), class 2 in 9 (22.5%), and class 3 in 4 (10%) cases. Angiographic improvement associated with progressive thrombosis of the aneurysm was obtained in 10 aneurysms. Four aneurysms were recanalized without requiring additional treatment. In-stent stenosis was found in one aneurysm, but stent migration was not seen on follow-up angiography.

Conclusion

Stent-assisted coil embolization using the Solitaire AB stent for treating wide-necked and/or complex intracranial aneurysms was found to be safe and effective immediately post-embolization and after follow-up. Long-term follow-up will be required to identify the effect of the Solitaire AB stent on recanalization rates.

Towards Predicting Patient-Specific Flow-Diverter Treatment Outcomes for Bifurcation Aneurysms: From Implantation Rehearsal to Virtual Angiograms

Despite accounting for the majority of all cerebral aneurysm cases, bifurcation aneurysms present many challenges to standard endovascular treatment techniques. This study examines the treatment of bifurcation aneurysms endovascularly with flow-diverting stents and presents an integrative computational modeling suite allowing for rehearsing all aspects of the treatment. Six bifurcation aneurysms are virtually treated with 70% porosity flow-diverters. Substantial reduction (>50%) in aneurysm inflow due to device deployment is predicted in addition to reductions in peak and average aneurysm wall shear stress to values considered physiologically normal. The subsequent impact of flow-diverter deployment on daughter vessels that are jailed by the device is investigated further, with a number of simulations conducted with increased outlet pressure conditions at jailed vessels. Increased outlet pressures at jailed daughter vessels are found to have little effect on device-induced aneurysm inflow reduction, but large variation (13–86%) is seen in the resulting reduction in daughter vessel flow rate. Finally, we propose a potentially powerful approach for validation of such models, by introducing an angiographic contrast model, with contrast transport modeled both before and after virtual treatment. Virtual angiograms and contrast residence curves are created, which offer unique clinical relevance and the potential for future in vivo verification of simulated results.

Comparison between Solitaire™ AB and Enterprise stent-assisted coiling for intracranial aneurysms

The aim of the present study was to analyze the feasibility, rate of procedure-related complications and midterm angiographic follow-up outcomes using the Enterprise (EP) and Solitaire™ AB (ST) stents in the stent-assisted coiling of intracranial aneurysms. In total, 81 patients with 90 aneurysms were included in the study, with the aim to treat 43 aneurysms with the EP stent (47.8%) and 47 aneurysms with the ST stent (52.2%). The 90 aneurysms were successfully stented and subsequently coiled; however, in four patients undergoing treatment with the EP stent, the stent was not navigable; thus, treatment with the ST stent was employed (EP, n=39, 43.3%; ST, n=51, 56.7%). Of the 90 aneurysms, 44 cases were ruptured aneurysms, with 74 located in the anterior circulation and 16 located in the posterior circulation. The stenting success rate of the ST stent was significantly higher compared with the EP stent. However, no statistically significant differences were observed with regard to the packing density, complete occlusion, progressive occlusion, recurrence rate, procedure-related complications, in-stent stenosis and stent migration rates between the two groups. In conclusion, the two common medical devices used for intracranial aneurysms are relatively safe and effective for the treatment of intracranial aneurysms. However, due to the higher stenting success rate of the ST stent, this medical devise was demonstrated to be more flexible and feasible compared with the EP stent.

Hybrid y stenting with the waffle-cone. A technical note

Endovascular treatment of wide-neck bifurcation aneurysms is challenging and often requires adjunctive techniques and devices. We report our experience with the hybrid Y stenting with the waffle-cone technique, combining Y stent-assisted coiling and waffle-cone stenting techniques. This approach has been described only in a single case report using a combination of open and closed cell stents. We describe four cases treated by hybrid Y stenting with the waffle-cone procedure with a variation from the originally reported technique, consisting in deploying two closed cell stents. All patients were successfully treated without complications. We propose hybrid Y stenting with the waffle-cone for the treatment of wide-neck bifurcation aneurysms as a bailout technique after failure of Y stent-assisted coiling.

Assisted coiling of saccular wide-necked unruptured intracranial aneurysms: stent versus balloon

BACKGROUND AND PURPOSE

Assisted coiling with stents or balloons enables a higher percentage of complete occlusions of saccular unruptured intracranial aneurysms to be achieved with a reasonable complication rate. The aim of this study was to compare stent-assisted coiling and the balloon remodeling technique in terms of efficacy, stability, and safety for the treatment of comparable unruptured saccular intracranial aneurysms.

MATERIALS AND METHODS

268 patients with 286 saccular unruptured wide-necked intracranial aneurysms were treated at our institution with stent- or balloon-assisted coiling and retrospectively reviewed. Statistical analysis was performed to assess significant differences between the two groups.

RESULTS

The rate of complete occlusion at the end of the procedure was higher with stent-assisted coiling than with balloon-assisted coiling (86.8% vs 78%) and the same results were also observed after 6 months (92.1% vs 77.6%; p=0.05). About 50% of major recurrences occurred in large to giant aneurysms (p<0.001). The overall complication rate was similar in the stent-assisted and balloon-assisted groups (10.3% vs 9.3%). Independently of the technique, a higher complication rate was observed with bifurcational aneurysms, particularly in the middle cerebral artery (p=0.016).

CONCLUSIONS

Stent-assisted coiling achieved better results in terms of complete occlusion and stability than balloon-assisted coiling with a lower rate of recurrence without being associated with a higher risk of intraprocedural complications. Bifurcational and large to giant aneurysms were associated with higher complication rates and higher recurrence rates, respectively, and still represent a challenge for both techniques.

Endovascular treatment of unruptured A1 segment aneurysms

Aneurysms of the A1 segment of the anterior cerebral artery (A1A) are rare and challenging to treat. Less information is available regarding their management by endovascular approach. We evaluated our experience of endovascular treatment in 15 patients with unruptured A1As. We retrospectively reviewed unruptured A1As treated by embolization at our hospital. The clinical data and angiographic results were reviewed. A special technique involving shaping microcatheter tips was used for catheterization. From September 2009 to December 2012, 15 patients presenting with unruptured A1As were identified. All the patients were treated by selective embolization including five patients with balloon-assisted coiling (BAC) or stent-assisted coiling (SAC). These adjunctive techniques were used to catheterize the sac safely or to protect a branch at the neck. According to the location and direction of the aneurysm, "Z-shaped", "S-Shaped" or "U-Shaped" microcatheter tip shaping was used for microcatheter positioning and stabilization. All patients showed an excellent clinical outcome. A complete aneurysm occlusion was obtained in all the patients. Endovascular treatment of A1As is feasible and associated with good results. Because of their location and close relationship with perforators, endovascular treatment of A1As sometimes requires the use of BAC or SAC. The microcatheter tip shaping technique is very important for coiling. Our results suggest that endovascular treatment is a suitable therapeutic option for unruptured A1As when the aneurysm size is optimal for embolization.