Modification by an aspiration catheter for vessel stretching in thrombectomy using a stent retriever in vitro.

OBJECTIVES: Post-thrombectomy subarachnoid hemorrhage, which is caused by vessel stretching when retrieving a stent retriever (SR), is a complication of endovascular mechanical thrombectomy (EVT) using an SR. This in vitro study examined the association between EVT for middle cerebral artery (MCA) occlusion and M2 vessel stretching depending on the positioning of the SR or combined use of SR and aspiration catheter (AC) technique (CBT). MATERIALS AND METHODS: A silicone vascular model was used. The maximum migration distance (MMD) in the anteroposterior view of an X-ray impermeable metal marker located at an M2 trunk 20 mm distal to the M1-2 bifurcation in angiographic images during an SR retrieval was calculated. According to the positioning of SR deployment (distal or proximal) and use of an AC [SR alone without an AC (SR alone) group, stent retrieval into an AC (SA) group, and stent-AC retrieval as a unit into a guiding catheter (SA unit) group], 60 attempts were conducted with each group of 10 attempts. RESULTS: In distal SR deployment, the MMD in the CBT group, consisting of SA and SA unit groups, was significantly smaller than the SR alone group (1.36 ± 0.32 mm VS 2.39 ± 1.10 mm; p = 0.001). In proximal SR deployment, the CBT group showed a tendency to decrease MMD (1.38 ± 0.33 mm VS 1.63 ± 0.28 mm; p = 0.077). CONCLUSIONS: This in vitro study showed that CBT might help modify the stretching of M2 when an SR is distally deployed in MCA occlusion.

Outflow angle: a risk factor for thromboembolic complications in coil embolisation for treating unruptured middle cerebral artery bifurcation aneurysms.

BACKGROUND: Thromboembolic complications are a relevant risk in coil embolisation of cerebral aneurysms. This retrospective study aimed to assess the treatment outcomes of unruptured middle cerebral artery (MCA) bifurcation aneurysms and the predictors for thromboembolic complications based on the aneurysm morphological characteristics. We examined the following three features: inflow angle, outflow angle (OA), and bifurcation angle, formed by the aneurysm and neighbouring blood vessels. METHODS: A total of 32 MCA bifurcation aneurysms were retrospectively investigated in 32 patients treated consecutively at our institute between April 2008 and March 2019. The predictors for thromboembolic complications were analysed in two groups: patients with and without thromboembolic complications. RESULTS: Perioperative thromboembolic complications were detected in six patients (18.8%), including two and six intra- and post-procedural thromboembolic complications, respectively; all cases were resolved. Regarding the aneurysms' morphological characteristics, the group with thromboembolic complications showed a significantly smaller OA (55.58° ± 14.05° vs. 86.04° ± 28.58°, P = 0.01) than the group without complications. Multivariate analysis revealed that smoking habits and OA < 70° were significant predictors of thromboembolic complications (smoking habits: P = 0.01, odds ratio [OR]: 6.89, 95% confidence interval [CI]: 3.78-12.62; OA < 70°: P = 0.04, OR: 3.19, 95% CI: 1.52-6.56). CONCLUSIONS: Our findings indicate significant pre-procedural predictors of thromboembolic complications to consider for safe treatment; clipping should be preferred to coil embolisation in high-risk patients. The method of choice should be considered in each case to allow the safe treatment of unruptured MCA aneurysms.

Predictors of Clopidogrel Hyper-Responsiveness in Neuro-Interventional Procedures.

BACKGROUND: Hyper-responsiveness to clopidogrel abnormally inhibits platelet aggregation and increases hemorrhagic complications. The present study investigated clinical factors related to clopidogrel hyper-responsiveness in neuro-interventional procedures. METHODS: Two hundred twenty-four patients receiving clopidogrel for coil embolization to treat unruptured cerebral aneurysm or carotid artery stenting to treat carotid artery stenosis at the internal carotid artery origin were retrospectively reviewed for their P2Y12 reactivity unit (PRU) values and clinical characteristics. Hyper-responsiveness to clopidogrel was defined as a PRU of <95. RESULTS: The mean PRU was 218.2 ± 77.8. Hyper-responsiveness to clopidogrel was observed in 12 patients (5.4%). Hyper-responsiveness was observed in younger patients, patients with a lower concentration of hemoglobin A1c, and patients with a higher low-density lipoprotein cholesterol (LDL-C) concentration compared with non-hyper-responsive patients (P = 0.01, P < 0.01, P < 0.01, respectively). On analysis of concomitant drugs, the patients in the hyper-responsive group were less frequently administered calcium channel blockers (CCBs) compared with the non-hyper-responsive group (P = 0.01). No significant differences in the usage of proton pump inhibitors or statins were observed. A LDL-C concentration of >120 mg/dL and no usage of CCBs were significant independent predictors of hyper-responsiveness to clopidogrel with a multivariate analysis (OR; 6.16, 95% CI, 1.57-26.64, P = 0.01, OR; 0.09, 95% CI, 0.01-0.82, P = 0.03, respectively). CONCLUSION: The present study shows that a higher LDL-C concentration and no usage of CCBs are independent predictors of clopidogrel hyper-responsiveness. These results are useful to predict perioperative hemorrhagic complications. Considering dose reduction of clopidogrel or alternative drugs in high risk cases is necessary to prevent perioperative hemorrhagic complications.

[Spontaneous Retroclival Subdural Hematoma Diagnosed Using Magnetic Resonance Imaging in an Adult Patient:A Case Report].

Spontaneous retroclival subdural hematoma is rare among adults. To the best of our knowledge, only six cases have been reported. A 73-year-old man presented with sudden severe headache, diplopia, and dysarthria, with no history of trauma. Head CT revealed a retrociliary hematoma. No obvious causes of bleeding, such as cerebral aneurysms or malformations, were detected. Conservative treatment was provided to the patient. MRI showed an intraventricular hemorrhage and a space between the basilar artery and hematoma three days after onset. The hematoma almost disappeared on day 7. MRI, particularly T2-weighted sagittal MRI, is effective in localizing hematomas and confirming intraventricular hemorrhages.

Transvenous embolisation via an occluded inferior petrosal sinus for cavernous sinus dural arteriovenous fistulas.

AIM OF THE STUDY: We retrospectively searched for cases of transvenous embolisation for cavernous sinus dural arteriovenous fistulas. MATERIALS AND METHODS: Twenty-five cases underwent transvenous embolisation via the inferior petrosal sinus (IPS). IPS was probed using a standard 0.035-inch guidewire for microcatheter navigation, which was successful in all cases. RESULTS: IPS was occluded in 17 cases (68%). Only one case experienced a complication, where the approach was changed to the contralateral side because of internal jugular vein injury. The relationship between the external auditory canal and the IPS route was reviewed in 18 cases using digital angiography (lateral view). The guidewire passed across, above, or below the external auditory canal in 10 (56%), six (33%), and two (11%) cases, respectively. CLINICAL IMPLICATIONS: No previous reports have analysed the relationship between the external auditory canal and the IPS route. We present a safe and successful technique for approaching the cavernous sinus via the IPS.

Transvenous Coil Embolization for the Treatment of Carotid Cavernous Fistula after Pipeline Placement: A Case Report.

The Pipeline embolization device (PED), a type of flow diverter, has become an appealing alternative treatment option for large or giant and wide-necked intracranial aneurysms. Carotid cavernous fistula (CCF) resulting from delayed aneurysmal rupture is a rare complication of PED placement with unknown pathophysiology. Here, we describe a case of CCF resulting from aneurysmal rupture following PED placement, and present the details of treatment by transvenous coil embolization. An 81-year-old woman was referred to our hospital for treatment of an 18.0 × 10.3 mm intracranial aneurysm located in the cavernous segment of the left internal carotid artery, noted during an examination of her diplopia. Endovascular treatment was conducted by positioning a single PED (4.75 × 25 mm) across the neck of the aneurysm. The postoperative course was uneventful, and the patient was discharged 8 days post procedure. On post-procedure day 10, her left oculomotor nerve palsy had worsened and she had developed left abducens nerve palsy, left exophthalmos, and left chemosis. Angiography demonstrated left direct CCF because of rupture of the aneurysm that had been treated with PED. Transvenous coil embolization was performed on post-procedure day 11 to treat the CCF, and complete resolution of the CCF and significant thrombus formation within the aneurysm sac were confirmed 11 days after the second procedure. Our angiographic results suggest that the aneurysmal rupture was caused by aneurysmal volume expansion associated with PED-induced thrombosis. Transvenous coil embolization for the treatment of CCF following PED placement constitutes a new challenge.

Convexity dural chondroma: a case report with pathological and molecular analysis.

Chondromas are rare benign tumors that commonly originate from the base of the skull, while those arising from the dura mater are less common. Although the molecular mechanism underlying its pathogenesis remains largely unknown, 12q13-15 rearrangements followed by the activation of HMGA2, which is associated with cell proliferation, have been reported in soft tissue chondromas. A recent comprehensive analysis of mesenchymal tumors identified an IDH1/2 mutation in cartilaginous tumors. However, these alterations have not yet been examined in dural chondromas. We here described clinical and pathological features in a new case of convexity dural chondroma with the wildtype IDH1/2 and expression of HMGA2 and reviewed the relevant literature.

Localized overexpression of alpha-internexin within nodules in multinodular and vacuolating neuronal tumors.

Multinodular and vacuolating neuronal tumors (MVNT) have been recently referred to as a distinctive neuronal tumor entity based on histopathological findings. They are characterized by multiple tumor nodules, vacuolar alteration and widespread immunolabeling for human neuronal protein HuC/HuD. Only 13 cases have been reported in the literature to date and little is known about the histopathology of these tumors. Herein, we report a case of MVNT with additional confirmation of immunohistochemical features. A 22-year-old woman presented with a continuous headache. MRI showed a subcortical white matter lesion with multiple satellite nodules in the frontal lobe appearing as T2/fluid-attenuated inversion recovery (FLAIR) hyperintensities. Histological examination of the resected lesion revealed well-defined multiple nodules composed of predominant vacuolating tumor cells. The tumor cells exhibited consistent immunolabeling for doublecortin, as well as HuC/HuD, both representative neuronal biomarkers associated with earlier stages of neuronal development. Immunopositivity for oligodendrocyte transcription factor 2 (Olig2) and S100 was also detected in tumor cells. Additionally, significant overexpression of alpha-internexin was observed in the background neuropil limited to tumor nodules. Neuronal nuclear antigen (NeuN), synaptophysin and neurofilament, markers for mature neurons, were either negative or weakly positive. The expression profile of neuronal biomarkers can be distinguished from that of classic neuronal tumors and is the immunohistochemical hallmark of MVNT. In summary, we identified the characteristic tumoral expression of HuC/HuD and doublecortin and the presence of abundant neuropil localized in MVNT tumor nodules, which exhibited widespread alpha-internexin expression. These results supported the presumption that MVNT is a distinct histopathological entity.

[A Case of Subgaleal Hematoma with Exophthalmos and Diplopia].

A 9-year-old girl struck the left side of her head on a doorknob, after which she gradually developed swelling. She was treated conservatively at another hospital before being referred and admitted to our hospital 9 days after injury, with complaints of exophthalmos and diplopia. Computed tomography (CT) scanning and magnetic resonance imaging (MRI) revealed a subgaleal hematoma (SGH). We therefore attempted to treat the patient by aspiration of the hematoma via needle puncture through the skin, for which we wrapped an elastic band around the head while infusing a hemostatic agent. No vascular anomalies and no abnormal shunts were identified by angiography under general anesthesia 13 days after injury. The patient was treated surgically due to increased head swelling and deteriorated exophthalmos. The liquefied, dark-red SGH was aspirated via a few cm of skin and a galeal incision on the left side of her head. A multiperforated drainage catheter was introduced into the hematoma cavity and the drainage catheter was connected to the vacuum-drain pump. After the surgery, the left exophthalmos disappeared. Twenty-three days after injury, she was discharged from our hospital without any neurological deficits.

Thromboembolic events associated with single balloon-, double balloon-, and stent-assisted coil embolization of asymptomatic unruptured cerebral aneurysms: evaluation with diffusion-weighted MR imaging.

INTRODUCTION: The introduction of the balloon remodeling and stent-assisted technique has revolutionized the approach to coil embolization for wide-neck aneurysms. The purpose of this study was to determine the frequency of thromboembolic events associated with single balloon-assisted, double balloon-assisted, and stent-assisted coil embolization for asymptomatic unruptured aneurysms. METHODS: A retrospective review was undertaken by 119 patients undergoing coiling with an adjunctive technique for unruptured saccular aneurysms (64 single balloon, 12 double balloon, 43 stent assisted). All underwent diffusion-weighted imaging (DWI) within 24 h after the procedure. RESULTS: DWI showed hyperintense lesions in 48 (40%) patients, and ten (21%) of these patients incurred neurological deterioration (permanent, two; transient, eight). Hyperintense lesions were detected significantly more often in procedures with the double balloon-assisted technique (7/12, 58%) than with the single balloon-assisted technique (16/64, 25%, p = 0.05). Occurrence of new lesions was significantly higher with the use of stent-assisted technique (25/43, 58%) than with the single balloon-assisted technique (p = 0.001). Symptomatic ischemic rates were similar between the three groups. The increased number of microcatheters was significantly related to the DWI abnormalities (two microcatheters, 15/63 (23.8%); three microcatheters, 20/41 (48.8%) (p = 0.008); four microcatheters, 12/15 (80%) (p = 0.001)). CONCLUSION: Thromboembolic events detected on DWI related to coil embolization for unruptured aneurysms are relatively common, especially in association with the double balloon-assisted and stent-assisted techniques. Furthermore, the number of microcatheters is highly correlated with DWI abnormalities. The high rate of thromboembolic events suggests the need for evaluation of platelet reactivity and the addition or change of antiplatelet agents.

Prospective registry of carotid artery stenting in Japan--investigation on device and antiplatelet for carotid artery stenting.

BACKGROUND: Carotid artery stenting (CAS) is minimally invasive but may cause perioperative cerebral infarction associated with distal embolization. We conducted a multicenter prospective observational study on the onset of vascular events after CAS to find out the efficacy and safety of CAS in Japan and to investigate the effects of antiplatelet drugs administered before and after CAS on efficacy and safety of CAS. METHODS: A total of 949 patients with cervical carotid artery stenosis were enrolled at 43 institutions in Japan; 934 who had undergone CAS with antiplatelet drugs and followed for 1 year were analyzed. Primary end point was the incidence of the first event of death, ischemic stroke, hemorrhagic stroke, transient ischemic attack, myocardial infarction, or serious hemorrhage within 1 year after enrollment. Comparison of the incidences of events according to antiplatelet drugs was also conducted. RESULTS: The primary end point was observed in 69 patients (7.4%) within 30 days of enrollment and in 40 patients (4.3%) between 31 days and 1 year after enrollment. The incidence of the first event for aspirin+cilostazol was significantly lower than that for aspirin+clopidogrel (P=.01), aspirin+clopidogrel+cilostazol (P=.01), and antiplatelet monotherapy (P<.01). Patient age (P=.01), presence of ischemic cerebrovascular disease (P=.02), presence of antidiabetic drugs (P<.01), femoral artery puncture (P=.02), guiding catheter used (P=.02), and Angioguard XP used (P=.01) were also correlated with the primary end point. CONCLUSION: Incidences of the primary end point within 30 days and 1 year of enrollment were comparable with previous reports, suggesting that CAS is a useful alternative for carotid endarterectomy in carotid stenosis patients with high risk for carotid endarterectomy. Further randomized controlled studies are needed to determine whether differences in mechanism of action of antiplatelet drugs might have contributed to the results of the present study.

[A case of glioblastoma multiforme in the pineal region with intraventricular hemorrhage].

INTRODUCTION: Glioblastoma multiforme (GBM) is a very rare type of tumor involving the pineal region. No case of pineal region GBM with tumoral hemorrhage has ever been reported. Here, we present the first such case report. CASE REPORT: A 65-year-old man presented with sudden-onset disturbance of consciousness. CT revealed intraventricular hemorrhage and acute hydrocephalus. The patient was treated by an emergent operation for ventricular drainage. MRI with contrast media showed a heterogeneous enhanced area in the pineal region. The patient underwent endoscopic biopsy surgery and a third ventriculostomy for non-communicating hydrocephalus. The pathological diagnosis was high-grade glioma, indicating the need for tumor removal via the occipital transtentorial approach. The tumor was removed subtotally and radiation and chemotherapy courses were then started. CONCLUSION: Pineal GBM with tumoral hemorrhage has never been reported before. Endoscopic operations are useful for rapid decision making prior to radical surgery.

Influence of size ratio on retreatment after coil embolization for unruptured bifurcation aneurysms.

Background: Aneurysm size is considered a risk factor for aneurysm rupture, and even small aneurysms may rupture, especially bifurcation aneurysms (BAs), which are occasionally detected. Therefore, we aimed to investigate the predictors of retreatment after coil embolization for unruptured BAs, with a particular focus on the absolute and relative size of the aneurysm (size ratio [SR]). Methods: To evaluate the predictors of retreatment, patients were divided into two groups: those with and those without retreatment. Patient characteristics and radiographic assessments were compared between the groups. SR was defined as the ratio of the maximum aneurysm diameter and the average diameter of the parent artery. Results: Overall, 181 unruptured BAs in 176 patients were investigated. The mean age of the patients was 63.8 ± 9.6 years. The mean aneurysm size and SR were 7.18 ± 2.94 mm and 2.49 ± 1.32, respectively. Further, 12 aneurysms with retreatment (6.6 %) and 169 aneurysms without retreatment were compared. In univariate analysis, SR was significantly higher in the group with retreatment (P = 0.02), but aneurysm size was not significantly different between the groups (P = 0.09). Multivariable analysis revealed that SR > 2.6 was a significant predictor of retreatment (P = 0.03; odds ratio: 10.41; 95 % confidence interval: 2.1-51.73). Conclusions: This study showed that SR influences retreatment after coil embolization for unruptured BAs. Therefore, if the aneurysm size and parent artery diameter were small, as in cases with a large SR, meticulous follow-up after coil embolization is required to detect recurrence and recanalization.

Cytotoxic Lesions of the Corpus Callosum Associated with Aneurysmal Subarachnoid Hemorrhage May Influence Shunt-Dependent Chronic Hydrocephalus.

BACKGROUND: Cytotoxic lesions of the corpus callosum (CLOCCs) are occasionally associated with aneurysmal subarachnoid hemorrhage (aSAH). The effects of aSAH on clinical outcomes in such cases are unclear. The present study aimed to investigate the frequency and characteristics of CLOCCs associated with aSAH to ascertain the predictors of shunt-dependent chronic hydrocephalus (SDCH) after aSAH. METHODS: We retrospectively investigated cases of aSAH treated by coil embolization. Patients were divided into those with and without CLOCCs. Between-group differences were evaluated, including clinical outcomes and the characteristics of both the patients and the aneurysms. Patients were divided into those with and without SDCH to identify predictive factors of SDCH after aSAH focusing on CLOCCs. RESULTS: This single-center study included 196 patients with aSAH. All patients received coil embolization between April 2013 and March 2020. CLOCCs were detected in 38 (19.4%) patients. In the group with CLOCCs, male sex, poor severity grade at onset, acute hydrocephalus, SDCH (all P < 0.01), and Fisher group 3 or 4 (P = 0.04) were significantly more common than in the group without CLOCCs. Diabetes and CLOCCs were significant predictors of SDCH after aSAH in multivariate analysis (diabetes: P < 0.01, odds ratio: 6.73, 95% confidence interval: 1.61-28.09; CLOCCs: P < 0.01, odds ratio: 6.86, 95% confidence interval: 2.87-16.38). CONCLUSIONS: CLOCCs and SDCH were common in patients with poor-grade aSAH, and CLOCCs were independent predictors of SDCH after aSAH. Meticulous follow-up is necessary to detect SDCH after aSAH, especially in patients with poor-grade aSAH and CLOCCs.

A Novel Braided Stent With Customized Simulation Software for Treatment of Intracranial Aneurysms: Multicenter Prospective Trial Before Unrestricted Clinical Application.

BACKGROUND AND OBJECTIVES: Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the "premarket" clinical trial of a new braided stent with a customized simulation software. METHODS: A stent system with 3 mesh density types (16, 24, and 32 wire mesh) was designed based on computational flow dynamics technology, and a simulation software (virtual stent planner [VSP]) was developed for the optimal stent deployment planning. Stents were selected after simulation on preoperative 3D-processed angioimages, and accuracy of the VSP was evaluated. RESULTS: Thirty-three unruptured intracranial aneurysms were successfully treated with VSP guidance. Twenty aneurysms (61%) were anterior circulation aneurysms, and 13 (39%) were posterior circulation aneurysms. The average aneurysm size was 7.1 mm, and the mean follow-up period was 19.2 months (11-39.0). There was no major recurrence or retreatment during follow-up, 2 morbidity cases, and no mortality. VSP planning presented slightly smaller stent dimensions compared with postdeployment: 24.2 vs 25.5 mm average, error -1.3 mm, and difference rate-5.46%. CONCLUSION: Based on this result, the new stents and software guidance system were approved by the Ministry of Health and Welfare as a combined medical device. VSP provided precise deployment with minimal error compared with actual stent and can contribute to better stent deployment even for less experienced physicians.

Trends and Progress in Neuroendovascular Treatment in Japan: Japanese Registry of Neuroendovascular Therapy (JR-NET) 4. Main Report.

We reported the main results of the Japanese Registry of Neuroendovascular Therapy (JR-NET) 4, a nationwide surveillance of therapy (NET) in Japan from January 2015 to December 2019. JR-NET 4 registered consecutive patients who underwent NETs by Japan Society of Neuroendovascular Therapy (JSNET) -certified specialists. The primary endpoint was functional independence (mRS score of 0-2) at 30 days post-NET, with secondary endpoints focusing on technical success and major adverse events within 30 days.A total of 63,230 patients and 60,354 NET procedures from 166 participating centers were analyzed. During the study period, NET cases have consistently increased, with an increase in the proportion of elderly patients. A significant trend shift was observed in the distribution of NET procedures, with endovascular treatment for acute ischemic stroke that showed a dramatic increase in 5 years. This trend aligns with key randomized clinical trials from 2015 that presented the efficacy of this treatment. Clinical outcomes at 30 days posttreatment revealed that endovascular treatment for acute ischemic stroke and other NETs maintained safety and effectiveness despite varying prevalence of functional independence between target diseases. The study also observed a steady increase in emergency treatment cases, reflecting the increase in acute ischemic stroke, a time-sensitive medical condition.This comprehensive surveillance highlights the trend of NET practices in Japan, driven by clinical evidence and advancements in treatment devices. Although these findings were specific to Japan, they offer valuable insights into the broader trends in NETs and acute stroke care.

Stroke outcomes of Japanese patients with major cerebral artery occlusion in the post-alteplase, pre-MERCI era.

This study examined outcomes of patients with acute ischemic stroke (AIS) with major cerebral artery occlusion after the approval of intravenous recombinant tissue-type plasminogen activator (IV rt-PA) but before approval of the MERCI retriever. We retrospectively enrolled 1170 consecutive patients with AIS and major cerebral artery occlusion (496 women; mean age, 73.9 ± 12.3 years) who were admitted within 24 hours after the onset of symptoms to 12 Japanese stroke centers between October 2005 and June 2009. Cardioembolism was a leading cause of AIS in this group (68.2%). The occlusion sites of the major cerebral arteries included the common carotid artery and internal carotid artery (ICA; 29.6%), middle cerebral artery (52.2%), and basilar artery (7.6%). Recanalization therapy (RT) was performed in 32.0% of patients (IV rt-PA, 20.0%; neuroendovascular therapy, 9.4%; combined, 2.5%). Symptomatic intracerebral hemorrhage within 36 hours with a ≥ 1-point increase in the National Institutes of Health Stroke Scale score occurred in 5.3% of the patients. At 3 months (or at hospital discharge), 29.3% of the patients had a favorable outcome (based on a modified Rankin scale score of 0-2), 23.8% were bedridden, and 15.6% died. After multivariate adjustment, RT was positively associated with a favorable outcome and negatively associated with death, whereas age, baseline National Institutes of Health Stroke Scale score, and ICA occlusion were negatively associated with a favorable outcome and positively associated with death. One-third of the patients with AIS and major cerebral artery occlusion were treated with RT, which was independently associated with favorable outcomes and death. However, 40% of the patients became bedridden or died during the post-alteplase, pre-MERCI era in Japan.

Acute Distal Migration and Shortening of the Flow-Redirection Endoluminal Device: A Case Report.

Objective: The flow diverter (FD) is a promising device. Apart from two main complications, hemorrhagic and ischemic ones, stent migration is reportedly an unusual complication. In particular, distal migration of the FD has rarely been reported. We report a case of asymptomatic acute distal migration of the flow-redirection endoluminal device (FRED). Case Presentation: A 50-year-old woman was incidentally diagnosed with an unruptured right internal carotid-ophthalmic artery aneurysm with a maximum diameter of 8.0 mm, and she subsequently underwent endovascular treatment with FRED. Based on the vessel diameter (3.8 mm proximal and 3.6 mm distal to the aneurysm), a 4.0-mm-diameter and 18-mm-long FRED was deployed without postoperative complications. However, on MRA 12 months after treatment, the aneurysm was not occluded; angiography showed distal migration of the FRED. The postoperative MRA and skull X-ray images were retrospectively reviewed to determine the period of the migration. The skull X-ray images and the signal loss area due to the FRED on MRA 1 day after the treatment had already demonstrated the migration of the FRED. In the second treatment, a 4.0-mm-diameter and 23-mm-long FRED was deployed in an overlapping fashion up to the proximal part of the carotid siphon. Prompt identification of distal migration of the FD without neurologic signs could be challenging. Conclusion: It is important to follow up meticulously with MRA and skull X-ray images after FD treatment for detecting stent migrations as early as possible.

Possible Contribution of the Aspiration Catheter in Preventing Post-stent Retriever Thrombectomy Subarachnoid Hemorrhage.

PURPOSE: This study aimed to identify factors related to the incidence of post-thrombectomy subarachnoid hemorrhage (PTSAH). METHODS: This retrospective, observational cohort study enrolled consecutive patients with acute ischemic stroke (AIS) due to the internal carotid artery (IC) top or middle cerebral artery (MCA) M1 or M2 segment occlusion who underwent single-pass stent retriever (SR) treatment between January 2015 and May 2022 at two acute care hospitals. RESULTS: Of the 54 included patients, 10 were in the PTSAH group (18.5%). The occlusion sites were IC top (31.5%), M1 segment (48.1%), and M2 segment (20.4%). Aspiration catheters (ACs) were used in 32 (59.3%) patients; however, the combined technique (AC advancement at least to the most proximal marker of SR) was actually used in 26 (48.1%) patients because a ledge effect at the ophthalmic artery origin from the IC interfered with distal navigation of the ACs. The baseline patient characteristics did not differ between the groups. M2 segment occlusion in the PTSAH and non-PTSAH groups were 40.0% and 15.9%, respectively (p = 0.19). More ACs were used in the non-PTSAH group (65.9% vs. 30.0%, p = 0.07). Significantly fewer combined techniques were performed in the PTSAH group (10.0% vs. 56.8%, p = 0.01). In multivariate analysis adjusted by variables with M2 segment occlusion and the combined technique, the combined technique (odds ratio 0.098; 95% confidence interval, 0.011-0.887; p = 0.039) was identified as a significantly associated factor for PTSAH. There was one PTSAH case (1.9%) with symptom worsening. CONCLUSION: The combined technique significantly influenced PTSAH occurrence as a preventive factor.

Inflow Angle and Height-Width Ratio are Predictors of Incomplete Occlusion at One and Two Years After Flow Diverter Treatment for Small- and Medium-Sized Internal Carotid Artery Aneurysms.

OBJECTIVE: We investigated the association between the inflow angle of aneurysms and their occlusion status at 1 and 2 years after flow diverter (FD) treatment. METHODS: We retrospectively analyzed 42 consecutive patients from a single center with 43 untreated, unruptured internal carotid artery (ICA) proximal to communicating segment, saccular aneurysms sized <12 mm. RESULTS: At 1 year posttreatment, the complete occlusion (CO) rate was 58.1%. On univariate analyses, the proportion of inflow angle >90° was significantly lower in the CO group than in the incomplete occlusion group (20.0% VS. 83.3%; P < 0.001). The CO incidence decreased with a height-width (H/W) ratio of <1.2 (P = 0.059). On multivariate analysis, an H/W ratio of <1.2 (odds ratio [OR], 0.076; P = 0.027) and an inflow angle of >90° (OR, 0.020; P = 0.0011) significantly influenced CO at 1 year post FD. At 2 years posttreatment, the CO rate was 76.3% (29/38 cases with available follow-up data). On univariate analyses, in the CO group compared to the incomplete occlusion group, the proportion of H/W ratio <1.2 was significantly lower (P = 0.005) and the proportion of inflow angle >90° was significantly lower (P = 0.021); aneurysm dome size tended to be larger (8.5 mm vs. 7.1 mm; P = 0.080). On multivariate analysis, an H/W ratio <1.2 (OR, 0.042; P = 0.015) and an inflow angle >90° (OR: 0.088; P = 0.031) significantly influenced CO at 2 years post FD. CONCLUSIONS: The inflow angle of >90° and H/W ratio <1.2 may significantly influence the CO rate in small- or medium-sized internal carotid artery aneurysms 1 and 2 years post FD.