Three-dimensional fusion imaging to assess apposition of low-profile visualized intraluminal support stent for intracranial aneurysm coiling.

Objective: To investigate on three-dimensional (3D) fusion images the apposition of low-profile visualized intraluminal support (LVIS) stents in intracranial aneurysms after treatment and assess inter-rater reliability. Materials and methods: Records of all patients with unruptured intracranial aneurysms who were treated with the LVIS stent were retrospectively accessed and included in this study. Two neurosurgeons evaluated the presence of malapposition between the vessel walls and the stent trunk (crescent sign) and the vessel wall and the stent edges (edge malappostion) on 3D fusion images. These images were high-resolution cone-beam computed tomography images of the LVIS stent fused with 3D-digital subtraction angiography images of the vessels. Associations between malapposition and aneurysm location were assessed by Fisher's exact test, and inter-rater agreement was estimated using Cohen's kappa statistic. Results: Forty consecutive patients were included. In all patients, 3D fusion imaging successfully visualized the tantalum helical strands and the closed-cell structure of the nitinol material of the low-profile visualized intraluminal support. A crescent sign was observed in 27.5 % and edge malapposition in 47.5 % of the patients. Malapposition was not significantly associated with location (p = 0.23 crescent sign, p = 0.07 edge malapposition). Almost perfect (κ = 0.88) and substantial (κ = 0.76) agreements between the two raters were found for the detection of crescent signs and edge appositions, respectively. Conclusions: 3D fusion imaging provided clear visualization of the LVIS stent and parent arteries, and could detect malapposition with excellent inter-rater reliability. This technique may provide valuable guidance for surgeons in determining postoperative management.

The white-collar sign after Neuroform Atlas stent-assisted coil embolization of unruptured intracranial aneurysms.

PURPOSE: Although stent-assisted technique is expected to help provide a scaffold for neointima formation at the orifice of the aneurysm, not all aneurysms treated with stent-assisted technique develop complete neointima formation. The white-collar sign (WCS) indicates neointimal tissue formation at the aneurysm neck that prevents aneurysm recanalization. The aim of this study was to explore factors related to WCS appearance after stent-assisted coil embolization of unruptured intracranial aneurysms (UIAs). METHODS: A total of 59 UIAs treated with a Neuroform Atlas stent were retrospectively analyzed. The WCS was identified on digital subtraction angiography (DSA) 1 year after coil embolization. The cohort was divided into WCS-positive and WCS-negative groups, and possible predictors of the WCS were explored using logistic regression analysis. RESULTS: The WCS appeared in 20 aneurysms (33.9%). In the WCS-positive group, neck size was significantly smaller (4.2 (interquartile range (IQR): 3.8-4.6) versus 5.4 (IQR: 4.2-6.8) mm, p = .006), the VER was significantly higher (31.8% (IQR: 28.6%-38.4%) versus 27.6% (IQR: 23.6%-33.8%), p = .02), and the rate of RROC class 1 immediately after treatment was significantly higher (70% vs 20.5%, p < .001) than in the WCS-negative group. On multivariate analysis, neck size (odds ratio (OR): 0.542, 95% confidence interval (CI): 0.308-0.954; p = .03) and RROC class 1 immediately after treatment (OR: 6.99, 95% CI: 1.769-27.55; p = .006) were independent predictors of WCS appearance. CONCLUSIONS: Smaller neck size and complete occlusion immediately after treatment were significant factors related to WCS appearance in stent-assisted coil embolization for UIAs using the Neuroform Atlas stent.

[Simulation for Endovascular Treatment].

With the advent of high-resolution imaging and advancements in computational fluid dynamics(CFD)and computational structural mechanics(CSM)analyses, clinical simulation of endovascular intervention has gradually become feasible. Virtual stents have become indispensable for coil embolization. For braided stents, such as those with low-profile visualized intraluminal support and flow diverters, predicting postplacement elongation and contraction is challenging; however, software development has enabled more precise treatment planning. Additionally, simulations utilizing three-dimensional(3D)printer models can enable realistic simulations of procedures such as intracranial stents and Woven EndoBridge placement. This approach is beneficial for shunt disorders such as arteriovenous malformations and dural arteriovenous fistulas, offering 3D visualization of shunt access routes and intuitive treatment strategy planning, even for beginners. Furthermore, it can be applied to procedures such as open surgical clipping and nidus resection, aiding in the selection of suitable clips and considerations for ideal resection based on nidus curvature. Simulations using CFD, CSM, and 3D printers are crucial for training surgeons and handling new devices. Harnessing medicine-engineering synergy is essential, and regulatory approval(insurance coverage)and appropriate commercialization of simulations are paramount for the future.

Risk factors and management of intraprocedural rupture during coil embolization of unruptured intracranial aneurysms: role of balloon guiding catheter.

Introduction: Intraprocedural rupture (IPR) is a serious complication of endovascular coil embolization of unruptured intracranial aneurysms (UIAs). Although outcomes after IPR are poor, methods to prevent subsequent neurological deterioration have not yet been investigated. We evaluated the risk factors and management strategies for IPR, particularly the role of balloon guiding catheters (BGCs) in rapid hemostasis. Methods: We retrospectively reviewed all UIA cases treated with coil embolization at three institutions between 2003 and 2021, focusing on preoperative radiological data, operative details, and outcomes. Results: In total, 2,172 aneurysms were treated in 2026 patients. Of these, 19 aneurysms in 19 patients (0.8%) ruptured during the procedure. Multivariate analysis revealed that aneurysms with a bleb (OR: 3.03, 95% CI: 1.21 to 7.57, p = 0.017), small neck size (OR: 0.56, 95% CI: 0.37 to 0.85, p = 0.007), and aneurysms in the posterior communicating artery (PcomA) (OR: 4.92, 95% CI: 1.19 to 20.18, p = 0.027) and anterior communicating artery (AcomA) (OR: 12.08, 95% CI: 2.99 to 48.79, p < 0.001) compared with the internal carotid artery without PcomA were significantly associated with IPR. The incidence of IPR was similar between the non-BGC and BGC groups (0.9% vs. 0.8%, p = 0.822); however, leveraging BGC was significantly associated with lower morbidity and mortality rates after IPR (0% vs. 44%, p = 0.033). Discussion: The incidence of IPR was relatively low. A bleb, small aneurysm neck, and location on PcomA and AcomA are independent risk factors for IPR. The use of BGC may prevent fatal clinical deterioration and achieve better clinical outcomes in patients with IPR.

Intermediate catheter use is associated with complete occlusion and dense packing in coil embolization of unruptured cerebral aneurysms: a propensity score matched study.

BACKGROUND: An intermediate catheter (IMC) can improve the maneuverability and stability of the microcatheter. OBJECTIVE: To investigate the efficacy and safety of using an IMC in triaxial systems for coil embolization of unruptured cerebral aneurysms (UCAs). METHODS: A total of 2430 consecutive saccular UCAs (2259 patients) that underwent initial coil embolization at three institutions between November 2003 and May 2023 were retrospectively reviewed. Patients were classified into two groups: with IMC (IMC(+)) and without IMC (IMC(-)). To investigate whether IMC use increased the rate of complete occlusion and the packing density, a propensity score-matched analysis was used to control for clinical, anatomical, and procedural features. RESULTS: Ultimately, 595 (24.5%) coil embolization used an IMC. Propensity score matching was successful for 424 paired IMC(+) and IMC(-) aneurysms. Compared with the IMC(-) group, the IMC(+) group had significantly higher rate of Raymond-Roy Occlusion Classification class 1 immediately after treatment (30.0% vs 20.8%, P=0.003) and at 6 months (28.8% vs 20.0%, P=0.004) and a higher volume embolization ratio (27.2% (SD 6.5%) vs 25.9% (SD 6.2%), P=0.003). Re-treatment rates were not significantly different between the two groups (0.7% vs 0.2%, P=0.624). No significant differences in the incidences of ischemic and hemorrhagic complications and IMC-related parent artery dissection were found between the two groups. CONCLUSION: Use of IMCs in triaxial systems can provide effective and safe support in coil embolization of UCAs because complete occlusion and dense coil packing can be achieved without increased complications.

Yield of Whole Body Computed Tomography in Hyper-Acute Stroke Patients With Large Vessel Occlusion.

PURPOSE: In the majority of cases, large vessel occlusion (LVO) in ischemic stroke patients has an embolic origin. Systemic embolism can occur simultaneously with brain thrombosis. This retrospective study evaluated the frequency and locations of systemic embolism in LVO stroke patients receiving revascularization therapy. MATERIALS AND METHODS: In our facility, we use contrast-enhanced computed tomography (CE-CT) to assess suspected stroke patients and routinely perform CE-CT from the chest to the abdomen after brain CT angiography to rule out contraindications like aortic dissection and trauma for thrombolysis. Systemic embolism is also assessed using these images, while myocardial infarction is evaluated based on electrocardiograms and laboratory findings. Other relevant clinical features of each patient are also analyzed. RESULTS: In total, 612 consecutively admitted stroke patients and 32 LVO patients who underwent revascularization therapy were included in the present study. Systemic embolism was identified in four patients (13%). The spleen was the most commonly affected organ, followed by the heart, kidneys, limbs, and lungs. All four patients with systemic embolism exhibited LVO resulting from embolism as the underlying mechanism. CONCLUSION: Systemic embolism was observed in 13% of our LVO patients, all of whom had LVO of embolic origin.

Local thrombolytics via balloon-assisted intra-arterial infusion as rescue therapy for thromboembolism during endovascular coil embolisation.

Thromboembolism is the most frequent complication of coil embolisation for intracranial aneurysm. Complications of thromboembolism can lead to stroke and have a serious impact on sequelae and mortality, necessitating appropriate rescue therapy. Here, we succeeded in recanalisation of an occluded stent by balloon-assisted local infusion of a thrombolytic agent following stent-assisted coil embolisation of an unruptured posterior communicating artery aneurysm. This method involves inflating a microballoon just distal to the occluded vessel and then administering a thrombolytic agent through a microcatheter. This technique may increase the rate of vessel reopening by maximising the local drug concentration. This method can be applied to any type of thrombolytic agent and helps reduce the dose of systemic drugs, which might decrease the incidence of haemorrhagic complications. Balloon-assisted intra-arterial thrombolytic infusion for an occluded vessel during endovascular coil embolisation could offer an alternative rescue therapy when conventional thrombolytic agent administration fails to improve thromboembolism.

Predicting difficult transradial approach guiding into left internal carotid artery on unruptured intracranial aneurysms.

Background: The transradial approach (TRA) is less invasive than the transfemoral approach (TFA), but the higher conversion rate represents a drawback. Among target vessels, the left internal carotid artery (ICA) is particularly difficult to deliver the guiding catheter to through TRA. The purpose of this study was thus to explore anatomical and clinical features objectively predictive of the difficulty of delivering a guiding catheter into the left ICA via TRA. Methods: Among 78 consecutive patients who underwent coil embolization for unruptured intracranial aneurysms through TRA in a single institution between March 1, 2021, and August 31, 2022, all 29 patients (37%) who underwent delivery of the guiding catheter into the left ICA were retrospectively analyzed. Clinical and anatomical features were analyzed to assess correlations with difficulty in guiding the catheter into the left ICA. Results: Of the 29 aneurysms requiring guidance of a catheter into the left ICA, 9 aneurysms (31%) required conversion from TRA to TFA. More acute innominate-left common carotid artery (CCA) angle (P < 0.001) and older age (P = 0.015) were associated with a higher conversion rate to TFA. Receiver operating characteristic analysis revealed that optimal cutoff values for the innominate-left CCA angle and age to distinguish between nonconversion and conversion to TFA were 16° (area under the curve [AUC], 0.93; 95% confidence interval [CI], 0.83-1.00) and 74 years (AUC, 0.79; 95% CI, 0.61-0.96), respectively. Conclusion: A more acute innominate-left CCA angle and older age appear associated with difficulty delivering the guiding catheter into the left ICA for neurointervention through TRA.

Risk factors for radial artery occlusion after neurointervention for unruptured intracranial aneurysm via transradial access.

PURPOSE: Neurointervention via transradial access (TRA) is less invasive than via transfemoral access. However, radial artery occlusion (RAO) may occur with TRA. The purpose of this study was to explore risk factors for RAO after coil embolization of unruptured intracranial aneurysms (UIAs) via TRA. METHODS: Forty-two consecutive patients who underwent coil embolization for UIAs via TRA between March 2021 and March 2022 and were available for angiographic evaluation 1 year after treatment were retrospectively reviewed. Multivariate logistic regression analysis was conducted to identify potential risk factors for RAO. RESULTS: Seventeen (40%) of the 42 patients showed RAO. Compared with the non-RAO group, radial artery size was significantly smaller (2.2 mm [interquartile range (IQR): 2.1, 2.4 mm] vs 2.6 mm [IQR: 2.5, 2.7 mm]; p = 0.001) and the incidence of radial artery spasm (RAS) was significantly higher in the RAO group. Multivariate analysis identified radial artery size (odds ratio [OR] 4.9 × 10-3, 95% confidence interval [CI] 6.4 × 10-5-0.38) and incidence of RAS (OR 14.8, 95%CI 2.1-105) as significant independent predictors of subsequent RAO. Based on receiver operating characteristic (ROC) curve analysis, the optimal cutoff for radial artery size was 2.5 mm (sensitivity, 82.4%; specificity, 76.0%; area under the ROC curve, 0.80 [95%CI 0.66-0.95]). CONCLUSION: Radial artery size and RAS represent reliable parameters for predicting RAO 1 year after coil embolization for UIA via TRA. Prophylaxis against RAS and limiting neurointervention via TRA to patients with radial artery larger than 2.5 mm in diameter may reduce the risk of postoperative RAO.

Efficacy and safety of fetal posterior cerebral artery stented coil embolization for fetal posterior cerebral aneurysms.

PURPOSE: Aneurysms at the origin of the fetal posterior cerebral artery (fPCA) often show fPCA bifurcation from the aneurysm dome, impeding complete embolization and dense coil packing. The recanalization rate for fPCA aneurysms is therefore high. This study aimed to evaluate the efficacy and safety of stenting into fPCA for aneurysms with fPCA incorporated into the aneurysm to determine whether stenting can provide effective embolization results and prevent recanalization. METHODS: A total of 19 consecutive coil embolization procedures between February 2012 and June 2022 for unruptured fPCA aneurysms with fPCA branching from the dome of the aneurysm were divided into two groups: non-stenting (NS) group (n = 11) and stenting into fPCA (PS) group (n = 8). Data were obtained retrospectively and compared regarding embolization results, complications, and recanalization. RESULTS: Compared with the NS group, the PS group achieved significantly higher complete occlusion rate and packing density (p < 0.001, p = 0.01, respectively). No symptomatic complications were observed in the PS group. Both immediately after stenting and at the 1-year follow-up, no stent kinking, stenosis, occlusion, or malposition were observed in any patients in the PS group. During 1-year follow-up, the cumulative minor and major recanalization-free rate after coil embolization for fPCA aneurysms were significantly higher in the PS group compared with the NS group (p = 0.022, 0.0024, respectively). CONCLUSION: Stenting into fPCA for aneurysms with fPCA incorporated into the aneurysm achieved high-density complete embolization without increasing complications, and prevented recanalization. The fPCA stent-assisted coil embolization can offer an alternative treatment for fPCA aneurysms.

The REMIT scale: A novel prediction scale for embolism in hyperacute stroke with large vessel occlusion.

BACKGROUND AND PURPOSE: Large vessel occlusion (LVO) in hyperacute ischemic stroke occurs mainly by one of two mechanisms, embolism or atherosclerosis. However, the mechanism is difficult to identify prior to treatment. We aimed to investigate the factors associated with embolic LVO in hyperacute ischemic stroke, and to develop a preoperative predictive scale for the event. MATERIALS AND METHODS: This retrospective multicenter study was conducted with consecutive ischemic stroke patients with LVO who underwent thrombectomy, thrombolysis, or both. The embolic LVO was defined as an occlusion that underwent recanalization with no residual stenosis. Multivariate logistic regression analysis for embolic LVO was performed to identity the independent risk factors. With this approach, a novel prediction scale (Rating of Embolic Occlusion for Mechanical Thrombectomy [REMIT] scale) was developed. RESULTS: A total of 162 patients (104 men; median age 76 years; interquartile range 68-83) were included in this study. Embolic LVO was observed in 121 patients (75%). Multivariate logistic regression analysis showed that embolic LVO was independently associated with high brain natriuretic peptide (BNP), high National Institutes of Health Stroke Scale (NIHSS) on admission, and absence of non-culprit stenosis (NoCS). The REMIT scale comprises high BNP (>100 pg/dL), high NIHSS (>14) and absence of NoCS, with one point for each risk factor. The frequencies of embolic LVO for the REMIT scale scores were as follows: score 0, 25%; score 1, 60%; score 2, 87%; score 3, 97% (C-statistic 0.80, P < 0.001). CONCLUSION: The novel REMIT scale has predictive value for embolic LVO.

Compartment syndrome associated with vascular avulsion caused by transradial access in neurointervention for unruptured intracranial aneurysm: illustrative case.

BACKGROUND: Transradial access (TRA) has a lower risk of access-site complications than transfemoral access but can cause major puncture-site complications, including acute compartment syndrome (ACS). OBSERVATIONS: The authors report a case of ACS associated with radial artery avulsion after coil embolization via TRA for an unruptured intracranial aneurysm. An 83-year-old woman underwent embolization via TRA for an unruptured basilar tip aneurysm. Following embolization, strong resistance was felt during removal of the guiding sheath due to vasospasm of the radial artery. One hour after neurointervention via TRA, the patient complained of severe pain in the right forearm, with motor and sensory disturbance of the first 3 fingers. The patient was diagnosed with ACS causing diffuse swelling and tenderness over the entire right forearm due to elevated intracompartmental pressure. The patient was successfully treated by decompressive fasciotomy of the forearm and carpal tunnel release for neurolysis of the median nerve. LESSONS: TRA operators should be aware that radial artery spasm and the brachioradial artery pose a risk of vascular avulsion and resultant ACS and warrant precautionary measures. Prompt diagnosis and treatment are essential because ACS can be treated without the sequelae of motor or sensory disturbance if properly addressed.

Thromboelastography 6s for assessment of platelet function during coil embolization of unruptured intracranial aneurysms.

OBJECTIVES: Methods for assessing platelet function in patients with neurovascular disease remain controversial and poorly studied. This study aimed to assess associations between thromboelastography 6s (TEG6s) measurements and postoperative ischemic complications in patients with unruptured intracranial aneurysms (UIAs) treated by coil embolization. METHODS: Eighty-four patients with UIAs taking a combined aspirin and clopidogrel protocol were retrospectively reviewed from January 2021 to May 2022. Blood samples were obtained for TEG6s to assess platelet function on the day of coil embolization. To identify acute ischemic complications, diffusion-weighted imaging (DWI) was performed within 24 h after coil embolization. Multivariate logistic regression analysis was conducted to identify potential risk factors for postoperative positive DWI (DWI (+)) lesions. RESULTS: Forty-three of the 84 patients (51%) with DWI (+) lesions were identified. Compared with patients without DWI (+) lesions, Adenosine diphosphate (ADP)-induced platelet-fibrin clot strength (MAADP) was significantly higher (53.6 mm [Interquartile range (IQR): 48.3-58.3 mm] vs 46.7 mm [IQR: 36.8-52.2 mm]; p=0.001) and ADP inhibition rate (ADP%) was significantly lower (19% [IQR: 11-31%] vs 31% [IQR: 21-44%]; p=0.001) in DWI (+) patients. Multivariate analysis identified MAADP, ADP%, and procedure time as significant independent predictors of subsequent DWI (+) lesions (odds ratios: 1.07, 0.96, and 1.02, respectively). Based on receiver operating characteristic curve analysis, MAADP >50.9 mm and ADP% <28.8% were associated with postoperative DWI (+) lesions in patients undergoing coil embolization for UIAs. CONCLUSIONS: MAADP and ADP% as assessed by TEG6s can offer reliable parameters to predict postoperative ischemic complications after coil embolization of UIAs. Lower MAADP values and higher ADP% may decrease the risk of postoperative ischemic complications.

Therapeutic efficacy and complications of radial versus femoral access in endovascular treatment of unruptured intracranial aneurysms.

PURPOSE: The transradial approach (TRA) in neuroendovascular treatment is known to have a lower risk of complications than the transfemoral approach (TFA). However, little research has focused on assessments of efficacy and risk of complications in the treatment of intracranial aneurysms. This study aimed to compare the efficacy and complications of TRA and TFA in coil embolization of unruptured intracranial aneurysms (UIAs) at our institution. METHODS: Consecutive patients who underwent endovascular surgery via TRA or TFA at a single institution from 1 April 2019, to 28 February 2022, were retrospectively analyzed. Patients were classified into TRA and TFA groups and assessed using propensity-adjusted analysis for outcomes including fluoroscopy time, volume embolization ratio (VER), and complications. RESULTS: A total of 163 consecutive UIAs were treated with coil embolization during the 35-months study period. The incidence of minor access site complications (ASCs) was significantly higher with TFA (20%, 25/126) than with TRA (2.7%, 1/37; p = 0.01). Propensity-adjusted analysis (matched for age, sex, aneurysm volume, embolization technique, and sheath size) revealed that TRA was associated with a lower risk of minor ASCs (odds ratio, 0.085; 95% confidence interval 0.0094-0.78; p = 0.029). However, TRA did not differ significantly from TFA with respect to fluoroscopy time, VER, major ASCs, and non-ASCs. CONCLUSIONS: Coil embolization for UIAs via TRA can reduce risk of minor ASCs without increasing the risk of non-ASCs compared with conventional TFA, and can achieve comparable results in term of efficacy and fluoroscopy time.

A novel 3-Fr guiding sheath for transradial access in aneurysm embolization: Technical note.

Neurointervention via transradial access (TRA) is challenging when the radial artery is narrow. We performed aneurysm embolization via TRA using a novel 3-Fr guiding sheath (GS) (Axcelguide; Medikit, Tokyo, Japan) with an outer diameter of only 1.76 mm for patients with a radial artery of inner diameter less than 2 mm, and described the whole procedure and pitfalls as a technical note. Here, we present two patients with radial arteries less than 2 mm. One patient had a narrow neck intracranial aneurysm at the bifurcation of the left vertebral artery and posterior inferior cerebellar artery, which was embolized with the primary coiling technique. The other was a patient with a wide-necked extracranial aneurysm in the cavernous portion of the right internal carotid artery, which was embolized with the transcell technique with stent. We utilized a 3-Fr GS, distal access catheter, and a 0.0165-inch microcatheter for coil embolization. All aneurysms were completely occluded, without neurological or puncture site-related complications including subcutaneous hematoma, radial artery occlusion, and vasospasm. This report provides the first description of neurointervention using a 3-Fr GS. The 3-Fr GS contributed to successful completion of TRA aneurysm embolization without neurological or puncture site-related complications in patients with radial arteries narrower than 2 mm. The 3-Fr GS may be useful to accomplish aneurysmal embolization via TRA even in patients with a small radial artery.

Horizontal stenting via retrograde route for recurrent ruptured posterior communicating artery aneurysm after clipping: A case report and literature review.

Treatment of recurrent ruptured aneurysms incorporating a branch vessel arising from the dome is challenging. Here, we attempted horizontal stent-assisted coil embolization via a retrograde route from the contralateral internal carotid artery to treat a small ruptured posterior communicating artery aneurysm incorporating a fetal variant posterior cerebral artery after clipping.

The meaning of non-culprit stenosis in hyperacute stroke with large vessel occlusion.

BACKGROUND AND PURPOSE: To diagnose atherosclerotic occlusion mechanism in acute ischemic stroke patients with large vessel occlusion prior to revascularization therapy is challenging. The aim was to verify the relationship between atherosclerotic occlusion and non-culprit stenosis detected in urgent neuroimaging prior to interventional procedure. MATERIALS AND METHODS: This study collected hyperacute stroke with large vessel occlusion, who underwent revascularization therapy (intravenous thrombolysis, thrombectomy, or both). An atherosclerotic occlusion was defined as an occlusion that did not recanalize or had residual stenosis at the initially occluded lesion, ensured in the second angiographic imaging performed after 1 week. The remaining patients who did not fulfill the definition of atherosclerotic occlusion was classified as embolic occlusion. A non-culprit stenosis was defined as a ≥ 50%-99% stenosis located other than the culprit occluded artery. Logistic regression analyses were performed to determine the factors independently associated with atherosclerotic occlusion. RESULTS: A total of 162 patients (104 men, median age 76 years old) were enrolled in our study. Forty one patients (25%) was atherosclerotic occlusion. Non-culprit stenosis was frequently observed in the atherosclerotic occlusion group than the embolic occlusion group (68% vs. 26%, P < 0.001). The presence of non-culprit stenosis was independently associated with atherosclerotic occlusion (OR, 11.00; 95% CI, 3.96-30.52; P < 0.001). CONCLUSION: In hyperacute stroke receiving endovascular therapy, non-culprit stenosis identification may be needed in order to perform an adequate revascularization, especially for atherosclerotic occlusion.

Risk factors for recanalization of dense coil packing for unruptured cerebral aneurysms in endovascular coil embolization: Analysis of a single center's experience.

In coil embolization of cerebral aneurysms, inadequate packing is known to increase the probability of recanalization. Even tightly embolized aneurysms may be recanalized, but predictive factors for recanalization have not been fully investigated. This retrospective study aimed to identify risk factors for recanalization of treated aneurysms with a volume embolization ratio (VER) ≥ 25%. A total of 301 unruptured aneurysms in 248 patients who underwent coil embolization between March 2012 and January 2021 were analyzed. Cases involving dissecting aneurysm, intraluminal thrombosis, parent artery occlusion, intraoperative rupture, re-treatment, rupture the day after surgery, postoperative coil migration, and postoperative parent artery occlusion were excluded due to the inaccuracy of VER. A total of 105 aneurysms (34.9%) treated with VER ≥ 25% were extracted. Clinical features (age, sex, medical history, family history), anatomical features (shape, location, aneurysm size, inflow angle, and volume), procedural features (stent-assisted, Raymond-Roy occlusion classification [RROC] immediately after treatment, re-treatment rate), and follow-up period were compared between Recanalization and Non-recanalization groups. Predictors of recanalization were determined using logistic regression and receiver operating characteristic (ROC) curve analyses. Eleven aneurysms were recanalized. In multivariate analysis, RROC class 3 (odds ratio [OR] 11.0; 95% confidence interval [CI] 2.03-59.4) and aneurysm volume (OR 1.005; 95%CI 1.001-1.008) were independent predictors of recanalization. ROC curve analysis showed optimal cutoff values for aneurysm volume of 69.5 mm3 (sensitivity, 81.8%; specificity, 72.3%). In coil embolization of unruptured aneurysms that VER ≥ 25%, cases with RROC class 3 or high aneurysm volume may be associated with a higher risk of recanalization, and should be carefully followed-up.

Characteristics of Unruptured Intracranial Aneurysms with Delayed Rupture Following Coil Embolization: Case Series and Review of the Literature.

Objective: Long-term clinical outcomes including delayed rupture of unruptured intracranial aneurysms (UIAs) after coil embolization (CE) remain unclear. The purpose of this study was to evaluate the precise timing of re-treatment for recanalized UIAs before rupture. Methods: From February 2012 to June 2020, a total of 197 patients with 207 UIAs underwent CE in our institution and were followed up for more than 6 months. The follow-up period, as well as morphological changes from treatment to recanalization, regrowth, and rupture, was retrospectively analyzed. Delayed rupture was defined as a rupture that occurred more than 1 month after CE. Results: The average length of follow-up was 48.7 months. Three of 207 UIAs (1.45%) ruptured after CE. The aneurysm locations were the middle cerebral artery (MCA), anterior communicating artery (AcomA), and internal carotid artery-posterior communicating artery (ICA-Pcomm). The annual rupture rate after CE was 0.36%. Immediately after the first CE, treated aneurysms were graded according to the Modified Raymond-Roy Classification with class II for MCA aneurysms and class IIIb for AcomA and ICA-Pcomm aneurysms. The ICA-Pcomm aneurysm was treated with two additional CEs and was finally graded as class I. In all cases, DSA or MRA before aneurysm rupture showed recanalization and regrowth of aneurysms. The average periods from final embolization to regrowth and from regrowth to rupture were 54.3 months (±16.8) and 2.3 months (±0.9), respectively. Conclusion: UIAs with recanalization and regrowth after CE should undergo re-treatment as early as possible.

Delayed Tentorial Subdural Hematoma Caused by Traumatic Posterior Cerebral Artery Aneurysm: A Case Report and Literature Review.

BACKGROUND Subdural hematoma (SDH) caused by traumatic intracranial aneurysm (TICA) is rare. TICAs are known to rupture easily, resulting in a high morbidity and mortality rate. Therefore, accurate diagnosis and treatment are crucial for preserving life. We describe a case of delayed SDH in the setting of posterior cerebral artery (PCA) aneurysm. CASE REPORT A 42-year-old man presented with sustained head injury from a traffic accident, and was being followed-up conservatively for traumatic SDH and subarachnoid hemorrhage. Three weeks after the head trauma, the patient developed a sudden deterioration of mental status and disorientation. Computed tomography revealed de novo SDH at the cerebellar tentorium. Computed tomography angiography and magnetic resonance imaging demonstrated TICA in the PCA. The patient was diagnosed with SDH due to a ruptured PCA aneurysm at the quadrigeminal segment. To avoid SDH growth due to re-rupture of the aneurysm, parent artery occlusion was subsequently performed with no complications. The patient was discharged home 2 months after endovascular treatment, with moderate disability. Follow-up angiography 2 years after the operation showed no recanalization, and the patient had returned to work. CONCLUSIONS TICA in the PCA can cause tentorial SDH with or without the presence of subarachnoid hemorrhage. Routine cerebrovascular assessment is crucial for head trauma with hematoma adjacent to the cerebellar tentorium. Parent artery occlusion via an endovascular procedure is an alternative treatment for TICA in the PCA that is less invasive than other approaches.