Large Internal Carotid Artery Aneurysms Research Articles

A Combination Technique of N-butyl-2-cyanoacrylate and Minimal Coils with Flow Control for Parent Artery Occlusion of a Giant Internal Carotid Artery Aneurysm: A Technical Note.

Parent artery occlusion for large or giant internal carotid artery aneurysms remains a necessary procedure in the era of flow diverters. Endovascular parent artery occlusion is currently performed using detachable balloons or coils, which are difficult to obtain or costly. At our institution, we have devised a technique for combining n-butyl-2-cyanoacrylate and coils with flow control to solve this problem. Patients who underwent parent artery occlusion for large or giant internal carotid artery aneurysms with a follow-up period of more than 12 months were included. Imaging outcomes were evaluated for complete or incomplete aneurysmal occlusion and with or without aneurysmal shrinkage. The clinical outcome was based on changes in the modified Rankin Scale. Ten patients (ten aneurysms) were included. Their average age and average follow-up period were 68.4 years and 36 months, respectively. Complete occlusion and favorable clinical outcome were observed in all cases. The parent artery occlusion using a combination of coils and n-butyl-2-cyanoacrylate with flow control technique is effective for both imaging and clinical outcomes.

Impact of blood viscosity on hemodynamics of large intracranial aneurysms

BackgroundHemodynamic factors play an important role in the formation and rupture of intracranial aneurysms. Blood viscosity has been recognized as a potential factor influencing the hemodynamics of aneurysms. Computational fluid dynamics (CFD) is one of the main methods to study aneurysm hemodynamics. However, current CFD studies often set the viscosity to a standard value, neglecting the effect of individualized viscosity on hemodynamics. We investigate the impact of blood viscosity on hemodynamics in large intracranial aneurysm (IA) and assess the potential implications for aneurysm growth and rupture risk. MethodsCFD simulations of 8 unruptured large internal carotid artery aneurysms were conducted using pulsatile inlet conditions. For each aneurysm, CFD simulations were performed at 5 different viscosity levels (0.004, 0.006, 0.008, 0.010, and 0.012 Pa·s). Differences in hemodynamic parameters across viscosity levels were compared using paired t-tests, and the correlation between viscosity and hemodynamic parameters was analyzed. ResultsIncreasing blood viscosity leads to significant decrease in blood flow velocity within aneurysms. Time-averaged wall shear stress (WSS) showed significant positive correlation with viscosity, particularly at the aneurysm neck. Oscillatory shear index (OSI) showed general decreasing trend with increased viscosity, while it displayed an irregular pattern in a few cases. ConclusionsVariations in viscosity markedly influence velocity, WSS, and OSI in aneurysms, suggesting a role in modulating aneurysm growth and rupture risk. Incorporating patient-specific viscosity values in CFD simulations is vital for accurate and reliable outcomes.

The Utility of the "LEONIS Mova" Steering Microcatheter in Flow Diverter Placement.

LEONIS Mova (SB-KAWASUMI LABORATORIES, Kanagawa, Japan, hereinafter called LEONIS Mova) is a steerable microcatheter (MC) that enables angle adjustment of the catheter tip using a hand-operated dial. LEONIS Mova may be useful for flow diverter placement when access to the distal parent artery with a conventional MC and microguidewire (MGW) is considered difficult or impossible. Here, we report three such cases encountered during flow diverter placement in large and giant internal carotid artery aneurysms. In Case 1, a strong S-shaped curve was observed in the proximal parent artery of a giant cerebral aneurysm, and the luminal structure of the parent artery was lost within the aneurysm. It was anticipated that the distal side of the parent artery would be difficult to access with conventional MC and MGW. By adjusting the tip of the LEONIS Mova toward the aneurysm outlet beyond the S-shaped curve, it was possible to induce the MGW to secure the distal parent artery easily. In Case 2, the inflow and outflow axes of the parent artery were completely misaligned at the site of the aneurysm, and stenosis was present in the distal parent artery. Firmly bending the catheter tip increased accommodation for the catheter, enabling the induction of an MGW to access the distal parent artery without kicking back. In Case 3, the lesion extended from the cavernous portion to the petrosal portion; however, by adjusting the tip of the LEONIS Mova toward the aneurysm outlet, it was possible to induce the MGW to secure the distal parent artery easily. In each case, the LEONIS Mova enabled more secure and prompt access to the parent artery than anticipated and facilitated flow diverter placement. Encountering difficult-to-access lesions is one reason endovascular treatment may be unsuccessful. The LEONIS Mova is an excellent device that can overcome this obstacle, and its utility in certain applications should be recognized.

Paraclinoid internal carotid artery aneurysm with delayed stent occlusion after deployment of a flow diverter stent involving the orifice of the anterior cerebral artery: illustrative case.

In-stent thrombotic occlusion is a serious ischemic complication that can also result in ischemia in the distal perfusion territory and the territory of side branches for the artery in which the flow diverter (FD) stent is deployed. A 49-year-old female with a large paraclinoid internal carotid artery (ICA) aneurysm was treated with an FD involving the orifice of the anterior cerebral artery (ACA). The antiplatelet dose was reduced because of an increased clopidogrel response postintervention. The patient developed aphasia 2 months later. Emergency magnetic resonance imaging and digital subtraction angiography of the brain indicated FD stent occlusion and a small infarct in the distal vascular territory of the ipsilateral ICA, but the anterior choroidal artery (AChoA) territory was preserved by collateral flow. Emergency superficial temporal artery to middle cerebral artery anastomosis was performed, and she was discharged without neurological deficit 2 weeks after the second operation. In-stent occlusion after FD deployment involving the orifice of the ACA can cause severe cerebral ischemia that requires an adequate antiplatelet effect and careful follow-up. The AChoA territory can be preserved by collateral blood flow even in cases of in-stent occlusion.

Mass Effect After Flow Diversion for Unruptured Large and Giant Cavernous or Paraclinoid Internal Carotid Artery Aneurysm

The mass effect associated with large or giant intracranial aneurysms is difficult for traditional endovascular treatment. This study investigated whether flow diverters can relieve the aneurysmal mass effect caused by aneurysmal compression symptoms. Fifty-five patients with unruptured large and giant intracranial aneurysms treated by a flow diverter at our institution from January 2014 to February 2022 were retrospectively evaluated. In this study, 53 patients were included. Initially, 27 patients (51.9%), including 10 with compressive optic neuropathy, 12 with third nerve palsy, 2 with facial hyperesthesia, and 11 with sixth nerve palsy, were symptomatic. The symptom duration was shorter in the improved group (n=2.2±4.0 vs. n=3.1±3.9, P=0.49). Thrombus formation following the flow diversion procedure was typically observed on magnetic resonance imaging (MRI) performed immediately and was not significantly associated with symptomatic improvement (OR=0.395; 95% CI (0.058-2.698), P=0.343). However, symptomatic improvement was seen in most patients when the aneurysm size decreased on MRI. A reduction in the aneurysm size on the MRI at the 3-month follow-up was correlated with symptomatic improvement in the multivariate analysis (OR=0.08, 95% CI (0.013-0.485), P<0.05). A flow diverter might help alleviate compression symptoms caused by large or giant intracranial aneurysms. Shrinkage of the aneurysm within 3months postoperatively and a shorter duration of symptoms contribute to the favorable outcomes of mass effect. Ultimately, prompt treatment is crucial for improving symptomatic intracranial artery aneurysms.

Letter: Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video.

To the Editor: We read with great interest the article “Transradial Flow-Diverting Stent Placement Through an Arteria Lusoria: 2-Dimensional Operative Video” by Hackett et al.1 The authors present a case of a patient with an arteria lusoria who received effective flow-diverting stent therapy for a large left internal carotid artery (ICA) aneurysm using a large bore guide catheter through right transradial access (TRA). Diagnostic angiography showed that the left ICA could be accessed through the right TRA. A 6F radial sheath was introduced into the right radial artery, and the sheath was then exchanged over a 0.035″ guidewire for an 8F 90-cm guide catheter (Infinity; Stryker Neurovascular). After navigating a 5F 130-cm Simmons catheter into the left common carotid artery through the arteria lusoria, the 8F guide catheter was delivered into the left ICA using the telescoping technique. The large left ICA-ophthalmic artery aneurysm was successfully treated with a pipeline embolization device (Medtronic). The importance of evaluating transradial diagnostic angiography to determine whether a catheter system can safely track into the target supra-aortic vessels is critical for successful transradial neurointervention in patients with arteria lusoria, and we wholeheartedly concur with the authors' conclusion on this point. Cannulation into the supra-aortic vessels through right TRA can be extremely challenging in patients with arteria lusoria because of unfavorable catheter trajectory.2 In addition, the right TRA can cause fatal arteria lusoria dissection.3 Therefore, transfemoral access is frequently employed as first-line access if neurointerventionalists encounter arteria lusoria.2 Previous study reported that left TRA is a technically feasible alternative in neurointerventions for patients with arteria lusoria.4 Nevertheless, a guide catheter may result in a failed TRA that necessitates a crossover to transfemoral access because of a failed cannulation, a kinked catheter, or an unstable system. We have used transradial access as the first-line access for neurointerventions.5-18 The first-line TRA using a 6F preshaped Simmons guiding sheath (outer diameter, 2.70 mm; inner diameter, 0.088″; usable length, 90 cm; 6F Axcelguide Stiff-J; Medikit) offers a large bore working channel and a high procedural success rate without catheter kinking or system instability even in patients with an unfavorable steep supra-aortic take-off.5-7,13 The 6F Simmons guiding sheath is fully engaged into the target common carotid artery with a pull-back maneuver (the pull-back technique) after reforming the Simmons curve within the ascending aorta. The Simmons curve can be reformed by anchoring the 6F Simmons guiding sheath to the descending aorta (the descending aorta anchoring technique) or contralateral subclavian artery (the subclavian artery anchoring technique) through the left TRA. Transradial carotid cannulation with the pull-back technique is technically simple and promising. As a result, left TRA with the 6F Simmons guiding sheath can be a beneficial treatment choice for performing anterior circulation procedures in patients with arteria lusoria. Finally, we would like to express our appreciation to the authors for their interesting article that advances the transradial neurointerventional method.

Combined Transarterial and Inferior Ophthalmic Vein Approach to a Direct Carotid-Cavernous Fistula: Technical Note

We describe our rescue technique for direct puncture of the inferior ophthalmic vein (IOV) for transvenous access of a direct, high-flow carotid-cavernous fistula (CCF). The CCF was caused by rupture of a large internal carotid artery aneurysm. Aneurysm and fistula embolization solely via the transarterial approach did not appear promising due to partial aneurysm thrombosis. Also, transvenous access via the facial vein failed due to extensive vessel tortuosity. Instead, the engorged and arterialized IOV was accessed by direct puncture with an 18-gauge venous cannula. After a small skin incision of the medial aspect of the lower eyelid and further transseptal puncture, the cannula was advanced stepwise between the maxillary bone and the bulbus oculi and below the medial rectus muscle to the IOV under repeated biplane roadmap guidance in 2 planes. Thereafter, the fistula and the aneurysm dome could be embolized with coils via a low-profile microcatheter. Hereby, a protective flow diverter was implanted via the arterial route into the internal carotid artery to seal the parent artery, prevent coil protrusion, and ensure permanent aneurysm occlusion. At 1-month follow-up, the aneurysm and CCF were completely occluded. Direct puncture of the IOV represents a feasible and minimally invasive approach for venous CCF access. The proposed method needs to be validated by further reports.

A Case of Large Intracavernous Internal Carotid Artery Aneurysm with Acute Spontaneous Thrombosis and Parent Artery Pseudo-occlusion

A Case of Large Intracavernous Internal Carotid Artery Aneurysm with Acute Spontaneous Thrombosis and Parent Artery Pseudo-occlusion

Preliminary Experience of the Surpass Streamline Flow Diverter for Large and Giant Unruptured Internal Carotid Artery Aneurysms.

As of January 2021, the Surpass Streamline (SS) is the most recently approved flow diverter in Japan. A total of 28 Japanese patients, including 9 clinical trial patients, with 28 large or giant unruptured internal carotid artery (ICA) aneurysms, underwent SS embolization at Juntendo University Hospital. Procedural failure occurred in two patients due to the difficulty to navigate the device in the tortuous parent artery. Therefore, 26 patients with 26 aneurysms were available for clinical and anatomical assessments. Patients' mean age was 62.6 years (range 46-86), and 24 patients (92.3%) were female. Mean aneurysm size and neck width were 15.4 mm and 7.7 mm, respectively, with 20 saccular and 6 fusiform aneurysms. Seven aneurysms were symptomatic due to the aneurysmal mass effect. Twenty patients underwent a 6-month follow-up angiography to evaluate the degree of occlusion. Anatomical outcomes were 12 (60%) complete occlusion (CO), 4 (20%) residual neck (RN), and 4 (20%) residual aneurysm. Favorable aneurysm occlusion consisted of CO, and RN was achieved in 16 (80.0%). There were no significant device stenoses. Aneurysmal mass effect improved in one and was unchanged in eight patients. There were three device-related complications, namely, delayed aneurysm rupture, minor ischemic stroke, and device occlusion (11.5%). One patient with minor ischemic stroke fully recovered before 30 days, and our series showed 7.7% risk of major ipsilateral stroke and neurological death at 30 days. The SS embolization for large and giant unruptured ICA aneurysms offers satisfactory anatomical and clinical outcomes with a low risk of device-related complications.

Compressive optic neuropathy caused by a flow-diverter-occluded-but-still-growing supraclinoid internal carotid aneurysm: illustrative case

BACKGROUNDFlow diverter stenting is an effective treatment for large proximal internal carotid artery (ICA) aneurysms. Cranial neuropathy caused by the mass effect of the aneurysm usually subsides over time. However, a new onset of compressive optic neuropathy after successful flow diverter stenting of a large proximal ICA aneurysm is seldom reported.OBSERVATIONSA 57-year-old woman had a right supraclinoid ICA aneurysm (approximately 17 mm) on magnetic resonance angiography (MRA) in a health checkup. She received intervention with the Pipeline embolization device. Six months later, she started to experience progressive hemianopia in the left half of the visual field. Nine months after stenting, MRA showed that the aneurysm was growing and causing mass effect, but digital subtraction angiography confirmed that the aneurysm was completely excluded from the circulation. She received a craniotomy for microsurgical decompression of the optic nerve and coagulation shrinkage of the aneurysm. Clipping and thrombectomy were not attempted. Her visual fields recovered gradually. Follow-up MRA showed that the aneurysm also diminished in size.LESSONSWhether the coagulation technique of the flow-diverter-occluded aneurysm alone is enough to cause satisfactory shrinkage and interaction between the flow diverter and the aneurysmal vasa vasorum/neointima formation should be further examined.

Comparison of hemodynamic stress in healthy vessels after parent artery occlusion and flow diverter stent treatment for internal carotid artery aneurysm.

De novo aneurysms generally develop in healthy vessels after parent artery occlusion for large internal carotid artery (ICA) aneurysm, possibly owing to increased hemodynamic stress in the remaining vessels. In recent years, there has been a shift toward flow diverter stent treatment. However, there is a lack of direct evidence and data that prove this change in hemodynamic stress in healthy vessels after parent artery occlusion and flow diverter stent treatment. The authors compared hemodynamic stress in healthy-side vessels before and after parent artery occlusion and flow diverter treatments. The authors included patients who underwent 3D cine phase-contrast MRI before and after large ICA aneurysm treatment. Spatially and temporally averaged volume flow rates and spatially averaged systolic wall shear stress (WSS) in healthy-side ICA distal to the posterior communicating artery (C1 segment according to Fisher's classification) were measured before and after parent artery occlusion and flow diverter treatments. Seventeen patients were included (5 patients in the parent artery occlusion group and 12 in the flow diverter group). At 1-2 months after treatment, median volume flow rate in healthy-side ICA increased from 5.36 ml/sec to 6.28 ml/sec (total increase 117%, p = 0.04) in the parent artery occlusion group and from 4.65 ml/sec to 4.93 ml/sec (total increase 106%, p = 0.02) in the flow diverter group. In the parent artery occlusion group, median WSS in the C1 segment of the healthy-side ICA increased from 3.91 Pa to 5.61 Pa (total increase 143%, p = 0.08); however, no significant increase was observed in the flow diverter group (4.29 Pa to 4.57 Pa [total increase 107%, p = 0.21]). Postoperatively, volume flow rate and WSS in the C1 segment of the healthy-side ICA significantly increased in the parent artery occlusion group. Therefore, the parent artery occlusion group was more prone to de novo aneurysm than the flow diverter group.

Intra-aneurysmal thrombosis and turbulent flow on MRI of large and giant internal carotid artery aneurysms

ObjectiveLarge and giant intracranial aneurysms are vascular pathologies associated with high morbidity and mortality. The purpose of this study was to assess large and giant internal carotid artery (ICA) aneurysms and their intra-aneurysm thrombosis and turbulent flow on magnetic resonance (MR) imaging. MethodsThis study investigated the large and giant ICA aneurysms in 12 patients. MR images, angiograms, and their treatment were retrospectively reviewed. ResultsMR imaging demonstrated high and intermediate signals in addition to the normal flow void. The heterogeneous MR intensities correspond to turbulent flow, laminar flow, or intramural thrombosis. Turbulent flow in 8 cases and intramural thrombosis in 4 cases. Angiography showed turbulent blood flow in saccular and fusiform aneurysms with smooth walls. Intra-aneurysm thrombosis was found in fusiform aneurysms associated with pathology of adjacent ICA wall. A growing saccular aneurysm of the ICA with regular wall involving a turbulent flow was observed. ConclusionThe turbulent flow and thrombosis in large and giant aneurysms can be detected on MR images. Most large and giant aneurysm is not fill with thrombus but turbulent blood flow. Partially thrombosed lesions are caused by pathology vessel wall not turbulent flow. Aneurysm growth can be caused by turbulent blood flow and intra-aneurysm thrombosis.

Long-term Follow-up Results after Flow Diverter Therapy Using the Pipeline Embolization Device for Large or Giant Unruptured Internal Carotid Artery Aneurysms: Single-center Retrospective Analysis in the Japanese Population.

Flow diverter (FD) therapy using Pipeline embolization device (PED) has become an important alternative to treat internal carotid artery (ICA) aneurysms. Herein, we report the long-term outcome for 3 years after FD therapy using PED for ICA aneurysms in Japan. The patients who underwent angiographical and/or clinical follow-up for 3 years after the FD therapy using PED of large or giant unruptured ICA aneurysms from December 2012 at our university hospital are the subjects of this study. We retrospectively reviewed the in- and outpatients’ medical charts, and written operative and radiological records. There were 84 patients with 90 aneurysms who could be clinically and/or angiographically followed up for 3 years. Of these, 7 aneurysms were only available for clinical follow-up. Of the remaining 83 aneurysms, 6 aneurysms had vessel occlusion due to stent thrombosis or parent artery occlusion, and 60 of the remaining 77 (77.9%) had complete occlusion. In multivariate analysis, older age (>70 years), wide neck, and non-adjunctive coiling contributed statistically significantly to incomplete occlusion. Of the 84 patients, 2 patients (2.4%) had delayed complications between 6 months and 3 years after the initial FD placement. Three patients (3.6%) had poor outcome due to postoperative major stroke complications, 2 of which were acute complications. The long-term results after FD therapy are good both angiographically and clinically. Endothelialization of the aneurysmal neck and intra-aneurysmal thrombosis contribute to complete occlusion. The primary reason for the somewhat low complete occlusion in Japan may be the patients are generally older.

Comparative Analysis of Feasibility of the Retrograde Suction Decompression Technique for Microsurgical Treatment of Large and Giant Internal Carotid Artery Aneurysms.

ObjectiveRetrograde suction decompression (RSD) is an adjuvant technique used for the microsurgical treatment of large and giant internal carotid artery (ICA) aneurysms. In this study, we analyzed the efficacy and safety of the RSD technique for the treatment of large and giant ICA aneurysms relative to other conventional microsurgical techniques. MethodsThe aneurysms were classified into two groups depending on whether the RSD method was used (21 in the RSD group vs. 43 in the non-RSD group). Baseline characteristics, details of the surgical procedure, angiographic outcomes, clinical outcomes, and procedure-related complications of each group were reviewed retrospectively. ResultsThere was no significant difference in the rates of complete neck-clipping between the RSD (57.1%) and non-RSD (67.4%) groups. Similarly, there was no difference in the rates of good clinical outcomes (modified Rankin Scale score, 0–2) between the RSD (85.7%) and non-RSD (81.4%) groups. Considering the initial functional status, 19 of 21 (90.5%) patients in the RSD group and 35 of 43 (81.4%) patients in the non-RSD group showed an improvement or no change in functional status, which did not reach statistical significance. ConclusionIn this study, the microsurgical treatment of large and giant intracranial ICA aneurysms using the RSD technique obtained competitive angiographic and clinical outcomes without increasing the risk of procedure-related complications. The RSD technique might be a useful technical option for the microsurgical treatment of large and giant intracranial ICA aneurysms.

Placement of a Pipeline Embolization Device: 2-Dimensional Operative Video.

Flow diversion has been a game-changer in the treatment of wide-neck large and giant cavernous and supraclinoid internal carotid artery (ICA) aneurysms as well as large vertebral artery aneurysms. Prior to their existence, carotid sacrifice or clipping with or without external to internal carotid artery bypass was the mainstay of treatment. Prior to flow diversion, endovascular coil embolization was often not effective as a stand-alone treatment because of the fact that many of these aneurysms present with symptoms created by mass effect on the cavernous sinus cranial nerves by the aneurysm. Packing the aneurysm with coils did nothing to alleviate the mass effect and did not prevent flow from entering the aneurysm. The continued flow causes coil compaction and aneurysm enlargement. Flow diversion addressed both these issues by diverting flow from the aneurysm while allowing the aneurysm to slowly thrombose and shrink. The video is a step-by-step account of this procedure in a 72-yr-old male with a large recurrence of a previously coiled cavernous ICA aneurysm. The procedure was performed following informed consent.

Flow Diverter Apposition in Patients with Large or Giant Intracranial Aneurysms Evaluated on Three-Dimensional Fusion Images Acquired by High-Resolution Cone-Beam Computed Tomography and Digital Subtraction Angiography

To investigate flow diverter (FD) apposition on fused images acquired by high-resolution cone-beam computed tomography (CBCT) and 3-dimensional (3D) digital subtraction angiography. Patients with large or giant internal carotid artery aneurysms treated with Pipeline FDs who underwent CBCT imaging at our institution between October 2016 and May 2019 were included. Two neurosurgeons measured the maximum malapposition between FDs and vessel walls on 3D fusion images of high-resolution CBCT images displaying the FD and 3D digital subtraction angiography images displaying the vessels. Associations between the relative malapposition, FD diameter, vessel diameter, proximal and distal vessel diameter discrepancy, and siphon angle were evaluated by linear regression analysis. Inter-rater and intermethod (3D and 2D image) agreements of the malapposition measurements were assessed by Bland-Altman analysis and by interclass correlation coefficients. Images of 2 patients were excluded because of image artifacts or fusion errors, and 3D fusion images were acquired in the remaining 26 patients. Our results did not suggest that relative malapposition was associated with vessel diameter (P= 0.12), vessel diameter discrepancy (P= 0.60), or syphon angle (P= 0.34), but relative malapposition increased by an estimated 13% (95% confidence interval: 4%-23%, P= 0.006) for each 1 mm increase in FD diameter. Inter-rater and intermethod agreements for apposition measurements were excellent and good, respectively. Three-dimensional fusion images provided clear visualization of structures of both the stent and parent artery with excellent diagnostic reliability. Careful deployment may be needed for FDs with larger diameters, as they tended to have larger relative malapposition.

Unpredictable times

A total of 475 participants from 61 countries responded to questions pertaining to the capacity to provide NI services, the volume of emergent cases encountered, and the expectations for future...

Carotid ligation for large internal carotid artery aneurysm

A 44-year-old woman presented with a 3-week history of right-sided throat fullness and earache. Computed tomography of the neck showed a 3.0-cm-wide and 6.1-cm-long aneurysm of the right cervical internal carotid artery (ICA), extending into the skull base (A-C/Cover). Options of aneurysm resection with interposition graft and carotid ligation were considered. Tortuosity of the artery precluded any covered stent option. Extension of the aneurysm beyond the skull base precluded a revascularization procedure because of inability to provide adequate distal control.

Use of Contralateral Trans-Anterior Communicating Artery Snare to Rescue Lost Access to a Pipeline Embolization Device Unsheathed in an Aneurysm.

A pipeline embolization device (PED; Medtronic, Minneapolis, MI, USA) is a new vascular reconstruction device used to treat large internal carotid artery (ICA) aneurysms in Japan. We herein present a PED-related complication and describe its rescue strategy. Rescue therapy using a snare via the posterior communicating artery from the contralateral side has already been reported. However, this is the first report of therapy via the anterior communicating artery (AcomA). A 49-year-old woman underwent vascular reconstruction with a PED for a large cavernous ICA aneurysm. During the placement of the PED, the proximal side of the PED slipped into the aneurysm. It was impossible to enter the true lumen of the PED from the proximal side because the orifice of the stent faced the aneurysmal wall. Contralateral trans-AcomA access to the PED was obtained through the distal ICA. The microwire from the distal ICA was connected with Goose Neck snares (Medtronic) from the proximal ICA. Pulling the snares to the proximal side, the PED was straightened and distal access was regained. Another PED was deployed such that it overlapped with the first PED to achieve vascular reconstruction. The patient finally recovered from aphasia, but paralysis of the right upper limb remained after rehabilitation. If the stent slips into the aneurysm, distal access through the true stent lumen may be very difficult. We presented a rescue technique for this complication, through the AcomA from the contralateral side.

Factors influencing blood flow resistance from a large internal carotid artery aneurysm revealed by a computational fluid dynamics model.

ABSTRACTHyperperfusion syndrome occurs after treatment of a large or giant cerebral aneurysm. Recently, flow-diverter stent placement has emerged as an effective treatment method for a large cerebral aneurysm, but postoperative ipsilateral delayed intraparenchymal hemorrhage occurs in a minority of cases. The mechanism underlying delayed intraparenchymal hemorrhage is not established, but one possibility is hyperperfusion syndrome. The incidence of delayed intraparenchymal hemorrhage appears to be higher for giant aneurysms; hence, we speculated that large/giant aneurysms may create flow resistance, and mitigation by flow-diverter stent deployment leads to hyperperfusion syndrome and delayed intraparenchymal hemorrhage. The purpose of this study was to identify aneurysm characteristics promoting flow resistance by the analysis of pressure loss in an internal carotid artery paraclinoid aneurysm model using computational fluid dynamics. A virtual U-shaped model of the internal carotid artery siphon portion was created with a spherical aneurysm of various angles, body diameters, and neck diameters. Visualization of streamlines, were calculated of pressure loss between proximal and distal sides of the aneurysm, and vorticity within the aneurysm were calculated. The pressure loss and vorticity demonstrated similar changes according to angle, peaking at 60°. In contrast, aneurysm diameter had little influence on pressure loss. Larger neck width, however, increases pressure loss. Our model predicts that aneurysm location and neck diameter can increase the flow resistance from a large internal carotid artery aneurysm. Patients with large aneurysm angles and neck diameters may be at increased risk of hyperperfusion syndrome and ensuing delayed intraparenchymal hemorrhage following flow-diverter stent treatment.