Objective: We report a patient with occlusion of the distal internal carotid artery (ICA), in whom angiography during mechanical thrombectomy revealed a shunt between the ICA and the cavernous sinus.

Case Presentation: A 79-year-old man with bile duct cancer, a liver abscess, septic shock, and atrial fibrillation presented to our hospital with sudden disturbance of consciousness, conjugate eye deviation, and right hemiplegia. A cranial CT revealed a hyperdense middle cerebral artery (MCA) and loss of gray-white matter differentiation, suggesting large vessel occlusion. Endovascular therapy was immediately initiated. Left internal carotid angiography indicated occlusion of the distal ICA at the origin of the ophthalmic artery. Injection of contrast medium at a site just proximal to the ICA occlusion depicted the cavernous sinus and inferior petrosal sinus. We withdrew the aspiration catheter to the petrous segment of the ICA and injected contrast medium again. This time, however, neither the cavernous sinus nor the inferior petrosal sinus was visualized. We deployed a stent retriever at the occlusion site and successfully removed the thrombus. The final angiography showed complete recanalization of the affected arterial segment with no sign of a carotid cavernous fistula. The patient was finally discharged on day 73 after endovascular therapy with a cerebral infarction in the territory of the left MCA.

Conclusion: In the present case, angiographic visualization of the cavernous sinus varied depending on the site of contrast medium injection. It appears that the high pressure of the contrast medium generated in the stump of the ICA opened up microvascular shunts between the normal capillaries of the ICA and the cavernous sinus, leading to visualization of the cavernous sinus. Therefore, it is important to be aware that injection of contrast medium into the blind alley of the ICA near the cavernous sinus could result in early visualization of the cavernous sinus.

Objective: During the perioperative period of carotid artery stenting (CAS), severe aortic stenosis (AS) is associated with a risk of serious complications, such as cardiac arrest. There is no consensus regarding the order of treatment for patients with severe AS concomitant with proximal carotid artery stenosis. We herein report a case in which CAS following transcatheter aortic valve implantation for severe AS was safely performed in an older high-risk patient.

Case Presentation: An 84-year-old woman presented with severe aortic stenosis that required treatment. Magnetic resonance angiography revealed severe left proximal internal carotid stenosis. Cerebral blood flow measurements revealed a normal cerebral perfusion. An uneventful transcatheter aortic valve implantation for severe aortic stenosis was followed by carotid stenting at a 2-month interval.

Conclusion: Staged treatment may be a safe and effective strategy in high-risk patients with concomitant severe AS and carotid stenosis. In cases with a normal cerebral blood flow, CAS following transcatheter aortic valve implantation can be a reasonable option, especially in older patients with multiple comorbidities.

Objective: We report a case in which coil embolization was performed for an angiographically occult ruptured anterior communicating artery aneurysm (Acom AN).

Case Presentation: A 91-year-old man was admitted to our hospital because of sudden deterioration of consciousness. Computed tomography (CT) revealed a diffuse subarachnoid hemorrhage in the basal cisterns, and CT angiography identified a 5-mm Acom AN. The next day, a catheter angiogram slightly visualized the neck portion of the Acom AN, despite no apparent visualization of the aneurysmal sac. We suspected intraluminal thrombosis of ruptured Acom AN, and intraaneurysmal coil embolization was performed to prevent re-rupture. By referring to the size and projection of the aneurysmal sac on CT angiography, a microcatheter was guided into the neck portion, and 3 platinum coils were successfully placed within the aneurysm without any complications. Eight days after coil embolization, recanalization of the aneurysm was suspected on magnetic resonance imaging (MRI). Another MRI obtained 17 days after coil embolization revealed gradual recanalization of the aneurysm, which was confirmed on catheter angiogram obtained 22 days after coil embolization. Additional intraaneurysmal coil embolization resulted in complete occlusion. Subsequently, the patient had an uneventful course without rebleeding and was transferred to a rehabilitation center.

Conclusion: We performed intraaneurysmal coil embolization for an angiographically occult ruptured Acom AN by referencing the neck position, aneurysm projection, and aneurysm size on CT angiography. Thus, angiographically occult aneurysms can be treated with endovascular coil embolization despite the need for close follow-up studies to detect recanalization.

Objective: Hematoma expansion in acute epidural hematomas occurred in 11.2%–32% of patients treated conservatively at initial presentation and required craniotomy. Middle meningeal artery (MMA) embolization has been reported to be effective in preventing hematoma expansion. We report a case of an asymptomatic acute epidural hematoma in which CTA was used to identify the source of bleeding. Embolization of the MMA was performed to prevent hematoma expansion.

Case Presentation: A 30-year-old male patient was admitted to the emergency department following a collision with a car while riding his motorcycle. The patient exhibited clear consciousness and no neurological deficits. A head CT scan revealed a right parietal and temporal bone fracture, and an acute epidural hematoma directly below the fracture site. The hematoma was small, and the patient was treated conservatively. Three hours later, a follow-up head CT scan revealed an enlarged hematoma. This hematoma was found near the transverse sinus. To identify the source of the bleeding, a CTA was performed, which revealed extravasation into the hematoma from an area distant from the transverse sinus. We performed embolization of the MMA. The postoperative course was good with no postoperative hematoma expansion.

Conclusion: CTA for acute epidural hematoma without neurological symptoms is a useful diagnostic tool that can identify patients at high risk for hematoma expansion. If the findings indicate the need for intervention, MMA embolization is a treatment option that may reduce the risk of hematoma expansion and craniotomy.

Objective: Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder characterized by mutations in the genes encoding transforming growth factor β (TGF-β). LDS is often associated with arterial tortuosity, aortic aneurysm, hypertelorism, and bifid uvula. Patients with LDS are at increased risk for vascular events due to aortic or cerebral aneurysms. We present the 1st reported instance of a carotid-cavernous fistula (CCF) in a patient with LDS.

Case Presentation: A 50-year-old male with LDS due to a pathogenic TGFBR2 variant presented with a 9-month history of bilateral tinnitus, right-sided exophthalmos, and conjunctival chemosis. Imaging revealed a direct Barrow type A CCF between the ventral wall of the internal carotid artery and the right cavernous sinus. The patient underwent transarterial embolization of the CCF using coils and 1 vial of ethylene vinyl alcohol copolymer. Postoperatively, the patient showed marked clinical improvement, with the resolution of pulsatile tinnitus and a gradual reduction of right-sided exophthalmos.

Conclusion: This case illustrates the successful endovascular management of a direct carotid-cavernous fistula in a patient with LDS. Careful pre-interventional imaging to rule out aortic aneurysm and meticulous catheter handling are necessary to achieve successful embolization.

Objective: Dural arteriovenous fistulas (DAVFs) in the superior orbital fissure (SOF) are extremely rare. We report a case of DAVF in the SOF and discuss the characteristics of angioarchitecture and the treatment strategies.

Case Presentation: A 72-year-old woman presented with chemosis, exophthalmos. Digital subtraction angiography revealed a right SOF DAVF mainly supplied from the accessory meningeal artery and the ophthalmic artery, which drained into the facial vein (FV) through the superior ophthalmic vein (SOV) without drainage into the cavernous sinus. A microcatheter was introduced into the shunt pouch via the FV and SOV, and coil embolization of the shunt pouch and SOV was performed, resulting in complete occlusion. However, 1 month later, DAVF recurred, with increased intraocular pressure and decreased vision. A semi-emergent transarterial glue embolization from the accessory meningeal artery was performed and complete occlusion was obtained.

Conclusion: SOF DAVFs often lack cavernous sinus drainage, and transvenous embolization via the FV is recommended if FV drainage is present, but transarterial embolization may be the next treatment of choice if transvenous embolization is unsuccessful.

Objective: Submucosal esophageal hematoma (SEH) is a rare complication of neuroendovascular therapy, and there are insufficient data on the management of antithrombotic therapy in cases of SEH. We report a case of SEH following flow diverter stenting for an unruptured cerebral aneurysm, successfully managed with conservative treatment, including short-term interruption of antiplatelet therapy.

Case Presentation: An 80-year-old woman on clopidogrel and aspirin underwent Pipeline flow diversion with adjunctive coil embolization for an unruptured right internal carotid-posterior communicating artery aneurysm under general anesthesia without complications. Postoperatively, the patient developed chest pain, and CT revealed wall thickening from the middle to lower esophagus, leading to a diagnosis of SEH. SEH in this case was likely caused by a combination of antiplatelet therapy, anticoagulants, nasogastric tube insertion, and mechanical stimulation from intubation and extubation during the operation. The patient was managed conservatively with fasting and discontinuation of antiplatelet therapy. After CT confirmed hemostasis, antiplatelet therapy was resumed with intravenous ozagrel sodium on postoperative day 3, switching to oral prasugrel on day 7. Upper gastrointestinal endoscopy (UGE) on day 8 showed the submucosal hematoma replaced by ulcers and fistula formation. UGE on day 15 showed improvement, and CT on day 23 confirmed hematoma resolution. The patient was discharged on day 24 without symptoms or complications.

Conclusion: In addition to previously reported cases, the presented case suggests that conservative management with temporary antiplatelet interruption and early resumption after hemostasis can lead to favorable outcomes in SEH cases associated with neuroendovascular therapy requiring antiplatelet therapy.

Objective: Cardiologists use the distal radial artery (dRA) approach in daily clinical practice. This method is gradually being applied in neuroendovascular treatment. However, limited studies have been reported concerning tumor embolization using small-bore guidance via dRA.

Case Presentation: Five consecutive tumoral cases underwent endovascular embolization via the dRA approach. The right dRA was punctured, with manual confirmation of pulsation or under the guidance of ultrasonography, using a 22-G plastic cannulation needle. After the insertion of a 0.021-inch guidewire, a dilator of a 4-Fr sheath enlarged the puncture site. The 22-G plastic cannulation needle was replaced with an 18-G cannulation needle, and a 0.035 guidewire was inserted to introduce a small-bore guide. A TEMPO4 (Cordis, Miami Lakes, FL, USA; outer diameter: 1.35 mm) or a 3.6-Fr JB2 (Gadelius Medical, Tokyo, Japan; outer diameter: 1.2 mm) was used in 4 cases to convey embolization materials, whereas a 4-Fr, 16-cm sheath (Terumo, Tokyo, Japan; outer diameter: 2 mm) combined with a 4-Fr SY3 (Gadelius Medical; outer diameter: 1.4 mm) was used in 1 case. Trisacryl gelatin microspheres or n-butyl-2-cyanoacrylate were used as embolization materials. Hemostasis was achieved with PreludeSYNC DISTAL (Merit Medical, South Jordan, UT, USA), and the median time ± standard deviation of hemostasis was 2.00 ± 0.77 h. No complications occurred after embolization.

Conclusion: Tumor embolization using small-bore guide via the dRA approach was completed without any complications.

Objective: Fenestrated basilar artery aneurysms (fBA-ANs) typically arise at the proximal bifurcation of the fenestration limb. It is reported that endovascular treatment with conventional coil embolization or balloon-assisted embolization techniques is often challenging and associated with a high complication rate, especially for wide-neck fBA-ANs. We present a case of fBA-AN successfully treated with stent-assisted coil (SAC) embolization using a novel one-and-a-half-lap approach with an open-cell stent, ensuring reliable neck coverage while preserving parent artery patency.

Case Presentation: A 33-year-old man with a history of an unruptured fBA-AN, previously treated with coil embolization via the double-catheter technique 6 years ago, presented with coil compaction and aneurysm recurrence. DSA revealed an fBA-AN measuring 8.7 mm in diameter, requiring retreatment. Under general anesthesia, SAC was performed using a one-and-a-half-lap approach. A Neuroform Atlas stent (Stryker Neurovascular, Fremont, CA, USA) was deployed via a 2.4 Fr microcatheter, positioned in a clockwise direction from the left loop fenestration to the right loop across the aneurysm neck, followed by coil embolization. Postoperatively, the patient remained free of ischemic complications, and follow-up imaging showed no recurrence of the fBA-AN.

Conclusion: This case demonstrates the efficacy of SAC with a one-and-a-half-lap approach using an open-cell stent for the treatment of complex fBA-ANs. This technique provides a viable treatment option for wide-neck fBA-ANs, ensuring durable aneurysm occlusion while maintaining parent artery patency.

Objective: The global increase in methamphetamine abuse has increased the incidence of methamphetamine-associated cardiomyopathy (MACM), which is often complicated by left ventricular thrombosis and acute ischemic stroke. Here, we report a case of left internal carotid artery occlusion during acute heart failure treatment in a patient with MACM that led to mechanical thrombectomy.

Case Presentation: A 54-year-old man with a history of approximately 30 years of methamphetamine abuse presented with dilated cardiomyopathy complicated by a left ventricular thrombus. On the night of admission for acute heart failure management, he experienced a sudden onset of consciousness disturbance, severe aphasia, and right hemiparesis. MRI revealed mild hyperintensities in the left cerebral hemisphere cortex and lenticular nucleus on diffusion-weighted imaging, with no abnormal signals on fluid-attenuated inversion recovery. He underwent mechanical thrombectomy, achieving complete reperfusion within 150 min; however, he experienced ipsilateral cerebral hyperemia that persisted for 30 days postoperatively. By the 90th postoperative day, moderate aphasia and mild paralysis of the right upper limb remained, with a modified Rankin Scale score of 3.

Conclusion: Left ventricular thrombosis is relatively common in patients with MACM, necessitating careful consideration of the risk of cardioembolic stroke.

Objective: Presurgical identification of the artery of Adamkiewicz (AKA) is crucial in thoracic and lumbar spinal lesions. Although CTA is widely employed to identify AKA, the detection rate varies across reports and is often difficult, especially in patients with spinal dural arteriovenous fistulas (SDAVFs). We report 2 cases where sublingual administration of nitroglycerin (NTG), a vasodilator, before CTA enabled good visualization of the AKA in patients with SDAVF.

Case Presentation: (Case 1) A patient in his 60s presented with progressive gait disturbance, and an MRI revealed a spinal vascular lesion. CTA with sublingual NTG administration revealed an SDAVF supplied by the right seventh intercostal artery and an AKA branching from the left ninth intercostal artery. A chronic descending aortic dissection was identified on CTA, but spinal angiography was not performed. The patient was successfully managed with direct surgical disconnection of the SDAVF, and his symptoms improved. (Case 2) A patient in his 60s presented with progressive bilateral lower-limb numbness, and a thoracic SDAVF was diagnosed using MRI. CTA without NTG administration failed to identify the AKA, but after the administration of NTG, a clear depiction of the AKA branching from the left 10th intercostal artery was obtained. Endovascular shunt occlusion was successfully performed via the right 10th intercostal artery, resulting in significant symptom improvement.

Conclusion: Sublingual NTG administration before CTA may improve AKA expression in patients with SDAVF.

Objective: Direct carotid-cavernous fistula (CCF) is a common neurovascular complication associated with Ehlers–Danlos syndrome (EDS). Nevertheless, reports indicate a significant incidence of treatment-related complications.

Case Presentation: We present a case of right CCF in a 28-year-old female with EDS. Femoral artery and vein punctures were performed under ultrasound guidance. We executed transvenous embolization (TVE) of the draining veins and the shunted fistula using a combination of coils and n-butyl-2-cyanoacrylate (NBCA), facilitated by an assisted transarterial balloon. The CCF resolved without any procedural complications.

Conclusion: Utilizing a combination of coils and NBCA in TVE is seen as a safe and efficient method for addressing CCF in patients with EDS. It enables preserving better visualization of the cavernous sinus and adjacent structures, making this approach particularly effective. By keeping a close watch, monitoring for potential high-risk complications, and strategically placing devices between the arterial and venous sides, the arterial puncture profile is reduced, enabling safer endovascular treatment.

Objective: Treatment of infectious aneurysms is challenging because of the fragility of the vessel walls. Surgical trapping and endovascular parent artery occlusion are the treatments of choice for medically intractable infectious aneurysms. Here, we describe a patient with an infectious aneurysm at the extracranial petrous segment of the internal carotid artery that was secondary to exudative otitis media; it was successfully treated with reconstructive endovascular interventions using a flow redirection endoluminal device (FRED).

Case Presentation: A 57-year-old man was administered antibiotics for exudative otitis media. After 6 months, the patient underwent CT screening, which revealed destruction of the petrous bone and a pseudoaneurysm at the petrous segment of the left internal carotid artery. Catheter angiography, including a balloon occlusion test, revealed a 47-mm wide-necked pseudoaneurysm at the distal cervical segment of the left internal carotid artery with poor collateral blood supply to the left internal carotid artery. We performed reconstructive endovascular treatment using a FRED. A follow-up catheter angiogram after 6 months confirmed a minor neck remnant of the aneurysm.

Conclusion: Flow diversion may be a useful treatment approach for extracranial infectious aneurysms, despite concerns about incomplete obliteration of the aneurysm and the persistent risk of re-rupture before complete obliteration.

Objective: Right aortic arch is a rare congenital anomaly. We report a case of mechanical thrombectomy for acute left medium-vessel occlusion due to a paradoxical embolism in a patient with a right aortic arch.

Case Presentation: An 81-year-old woman presented with severe right-sided hemiparesis and aphasia. The National Institutes of Health Stroke Scale score was 16, MRI demonstrated a diffusion-weighted imaging Alberta Stroke Program Early CT score of 7, and MRA revealed left M2 occlusion. CTA revealed a right aortic arch with mirror image branching. Mechanical thrombectomy was conducted using the usual system, and effective recanalization was achieved with a stent retriever and aspiration catheter after 3 passes. CTA revealed pulmonary embolism and deep vein thrombosis (DVT) in the right deep femoral vein, and transesophageal echocardiography demonstrated a patent foramen ovale. Electrocardiography did not reveal atrial fibrillation, and other examinations did not reveal any other cause; therefore, a paradoxical cerebral embolism was diagnosed. After anticoagulant therapy, no recurrence of infarction, pulmonary embolism, or DVT was observed. Severe right hemiparesis and total aphasia did not improve, and the patient was discharged on day 37 after admission with a modified Rankin Scale score of 5.

Conclusion: Access to the left common carotid artery in right aortic arch cases can be anatomically challenging. Preoperative imaging evaluation of the access route is crucial for quick and safe mechanical thrombectomy.

Objective: To assess the efficacy of mechanical thrombectomy (MT) for cerebral venous sinus thrombosis associated with Ewing sarcoma invasion into the venous sinus.

Case Presentation: A 48-year-old woman presented to our hospital with left hemifacial paralysis. The patient had undergone surgical treatment for left subclavian Ewing sarcoma 24 years ago. Furthermore, the patient had undergone tumor resection for very late metastasis in the left occipital bone and mastoid air cells 3 years prior to her admission. As the Ewing sarcoma had extended to the left transverse sinus, the sinus was resected during craniotomy. The tumor remained in the mastoid air cells, and radiotherapy was administered. On admission to our hospital, FLAIR revealed hyper-intensities in the straight sinus and the superior sagittal sinus. Magnetic resonance venography revealed no signal in the posterior part of the superior sagittal sinus and the bilateral transverse sinuses. The patient was diagnosed with cerebral venous sinus thrombosis, and anticoagulation therapy was administered. However, the swelling and pain on the left side of the face worsened, and intraocular pressure (IOP) increased. Therefore, an MT was performed. After endovascular treatment, the patient’s facial swelling and pain were reduced, and IOP returned to normal. Pathological examination of the captured thrombus revealed tumor cells, suggesting venous sinus invasion of Ewing sarcoma.

Conclusion: Although it was a palliative treatment, MT was effective in confirming the diagnosis of tumor invasion into the venous sinus and improving the patient’s quality of life.

Objective: A hyperplastic anterior choroidal artery (AchA) is a rare anomalous vessel that perfuses the posteromedial aspects of the cerebrum in place of the posterior cerebral artery. We describe 3 cases of hyperplastic AchA found among 61 patients with AchA aneurysms who underwent surgical or endovascular treatment at our institution.

Case Presentation: All 3 cases were diagnosed as hyperplastic AchA type 2 according to the Takahashi classification, indicating an anomalous branching temporal artery perfusing the medial temporal lobe. We performed coil embolization for 2 cases and surgical clipping for the third. One embolization case experienced recurrence after 3 years and underwent clipping. All procedures were conducted without complications.

Conclusion: Hyperplastic AchA can be encountered during aneurysm treatment. These cases emphasize the importance of evaluating the vascular anatomy to determine the optimal treatment strategy.

Objective: Herein, we present a novel flow reversal technique using dual-balloon inflation that can provide enhanced catheter stability and reliable embolic protection for percutaneous antegrade stenting in a patient with right common carotid artery (CCA) stenosis.

Case Presentation: A 75-year-old female patient with post-radiation right CCA stenosis initially underwent stenting using distal filter protection, which resulted in transient left upper limb paralysis caused by embolic infarction. After restenosis at 6 months, retreatment was performed using dual-balloon occlusion with the 9-F balloon guiding catheter in the innominate artery and the 8-F balloon guiding catheter in the right subclavian artery. Intraoperative ultrasonography confirmed a successful flow reversal, and debris was captured from the aspirated blood. The patient was discharged without neurological deficits, and postoperative imaging showed no new ischemic lesions.

Conclusion: The novel flow reversal technique using dual-balloon inflation can be effective and safe for treating right CCA stenosis by achieving both reliable embolic protection and improved catheter stability.

Objective: Not many reports of subclavian artery occlusion complicated by vertebrobasilar junction aneurysm have been published, and no cases have been treated using a distal radial approach. Our case report highlights the effectiveness of this approach in comparison to previous findings.

Case Presentation: An 82-year-old woman was referred to our hospital because of an enlarged vertebrobasilar junction aneurysm. The DSA and CTA results revealed a left subclavian artery occlusion, meandering of the descending aorta, and an aneurysm of the descending aorta. We performed coil embolization using the right radial and left distal radial artery approaches. Considering that the left subclavian artery occlusion was related to the aneurysm enlargement, we decided to perform left subclavian artery stenting. Left subclavian artery stenting was performed 1 month after coil embolization using the same approach. The patient was discharged on postoperative day 8 without complications.

Conclusion: Vertebrobasilar junction aneurysm and subclavian artery occlusion were treated via a safe and minimally invasive approach through the right radial and left distal radial artery approaches.

Objective: Cerebral infarction is a major perioperative complication of transcatheter aortic valve replacement (TAVR). The number of patients undergoing TAVR has been increased annually. Therefore, neurosurgeons and neurologists who engage in stroke therapy, including mechanical thrombectomy (MT), may have more opportunities to treat stroke patients after TAVR in the future. We herein report a case of MT that was performed for cerebral infarction after TAVR.

Case Presentation: A 92-year-old woman presented with right upper extremity weakness 1 day after undergoing TAVR. On diffusion-weight MRI, most regions of the left middle cerebral artery (MCA) showed a high signal intensity due to the occlusion of the left MCA. She was diagnosed with cerebral infarction due to left M2 occlusion and underwent MT using a stent retrieval and aspiration device under proximal flow arrest using a balloon guide catheter. After thrombectomy, angiography revealed thrombolysis in cerebral infarction (TICI) 3 revascularization. Histopathological analysis of the retrieved embolus revealed vascular endothelial cells surrounding a portion of the tissue and an interstitium composed of fibrotic tissue without any atheromatous lesions. The embolus was believed to consist of part of the valve tissue because an atheromatous lesion was not formed in the valve tissue, and no smooth muscle-rich media were observed, unlike in the artery wall.

Conclusion: Cerebral embolism after TAVR can be caused by emboli from valve tissue. In such cases, MT using a combined technique with proximal flow arrest may be effective.

Objective: There are only a few reports about flow diverter (FD) placement for large thrombosed aneurysms of the middle cerebral artery (MCA). We present a case of FD placement for a recurrent large thrombosed aneurysm of MCA at our hospital.

Case Presentation: A 72-year-old man with transient visual field disturbance underwent craniotomy for a large aneurysm in the left MCA; dome clipping was performed because of severe arteriosclerosis. Over several years, the residual aneurysm gradually increased in size, and despite antiplatelet therapy, the patient experienced repeated cerebral infarctions due to intra-aneurysmal thrombosis. A closer examination revealed that the M2 superior trunk was occluded. Thus, we performed FD placement, without further complications. After 6 months, the aneurysm was confirmed to be occluded with an O’Kelly–Marotta grading scale (OKM grade) of D. There was no enlargement of the thrombus inside the aneurysm, and the patient is currently under follow-up observation.

Conclusion: FD placement may be an option for large thrombosed aneurysms of MCA that are difficult to treat with conventional methods.

Objective: Persistent left superior vena cava (PLSVC) is rare, occurring in approximately 0.3%–0.5% of the population. In endovascular treatment (EVT), the left internal jugular vein (IJV) is approached via the left innominate vein from the superior vena cava; however, the left innominate vein is occasionally absent in patients with PLSVC. Careful consideration is required when performing EVT, particularly transvenous embolization (TVE).

Case Presentation: A 70-year-old female presented with a left cavernous sinus dural arteriovenous fistula. Left external carotid angiography findings showed that multiple feeders from the ascending pharyngeal artery, accessory meningeal artery, middle meningeal artery, and the artery of the foramen rotundum had formed a shunted pouch posterolateral to the left cavernous sinus. We initially planned to perform a TVE via the right femoral vein. However, PLSVC was detected on common carotid artery angiography. Consequently, a TVE via the left IJV and coil embolization were performed, resulting in the disappearance of the shunt. The patient was discharged without neurological deficits. PLSVC is a rarely observed thoracic venous malformation, with few reports concerning its management in cerebrovascular EVT. Contrast-enhanced computed tomography is useful for diagnosis; however, most patients with PLSVC are clinically asymptomatic and this abnormality is typically an incidental finding, remaining challenging to detect during a preoperative examination.

Conclusion: It is essential to consider the possibility of PLSVC and to verify the appropriate access route, including the right atrial level and the venous phase, during preoperative cerebral angiography.

Objective: Endovascular thrombectomy is widely performed for acute ischemic stroke due to proximal intracranial artery occlusion. The femoral artery is often selected for puncture. However, common carotid artery puncture may be considered in more challenging cases. When the internal carotid artery is occluded or obstructed by atherosclerosis, puncturing the distal internal carotid artery becomes necessary. This is rare and was reported in only 2 cases. We report here a case of endovascular thrombectomy using direct puncture of the internal carotid artery.

Case Presentation: A 76-year-old male presented with sudden-onset right upper limb hemiparesis and mild dysarthria. Hospital admittance 1 hour later. Diffusion-weighted imaging (DWI) on head MRI revealed a hyperintense area in the left basal ganglia and corona radiata. MRA showed occlusion of the left internal carotid artery and the M2 segment of the left middle cerebral artery. Intravenous tissue plasminogen activator (tPA) was initiated, and endovascular thrombectomy was attempted. However, navigating the occluded left internal carotid artery was impossible. Symptomatic improvement was observed with tPA therapy causing recanalization of the M2 segment. Thus, further treatment was halted. Two days later, aphasia and complete right hemiparesis developed. MRA revealed no left anterior circulation flow. Under general anesthesia, an incision parallel to the left sternocleidomastoid muscle was made, and a direct puncture of the left internal carotid artery was performed to complete thrombectomy.

Conclusion: In difficult-to-access cases, especially when considering puncturing the cervical vessels, our report suggests that exposing the cervical vessels first can improve the hemostasis and puncture performance.

Objective: Dural arteriovenous fistulas (dAVFs) in the paracavernous sinus of the sphenoid wing often present challenges for transvenous access because of their complex venous drainage patterns. Herein, we report the successful diagnosis and treatment of a greater sphenoid wing dAVF using a percutaneous transvenous approach via the Labbé vein.

Case Presentation: A 48-year-old woman presented with tinnitus and was diagnosed with a greater sphenoid wing dAVF. The dAVF was fed by multiple meningeal arteries from the accessory meningeal artery. Shunted blood drained retrogradely into the superficial middle cerebral vein (SMCV) and bilateral inferior petrosal sinus (IPS) via the cavernous sinus (CS). Although communication was observed between the shunt pouch and the lateral part of the CS, the tortuous and narrow nature of this connection suggests difficulty in accessing the shunt pouch via the IPS. Conversely, the SMCV, which served as the primary outflow pathway, was adequately connected to the vein of Labbé with minimal difficulty, facilitating the passage of the microcatheter. The percutaneous transvenous approach via the Labbé vein successfully reached the SMCV and achieved complete obliteration with selective transvenous embolization (TVE) using coils. The symptoms of the patient improved postoperatively, and the patient was discharged without complications.

Conclusion: Greater sphenoid wing dAVFs often rely on the SMCV as the major drainage route, making venous approaches challenging. The route via the vein of Labbé through the cortical veins to reach the SMCV proved to be a valuable access route for TVE of greater sphenoid wing dAVFs.

Objective: The optimal treatment strategy for large-vessel occlusion (LVO) related to intracranial atherosclerotic disease (ICAD), particularly for tandem lesions that complicate access and device delivery, remains unclear. We report a case in which angioplasty with a stent retriever (SR) and combined antithrombotic therapy was effective in treating re-occlusion associated with dissection of the residual stenosis after thrombectomy for acute atherosclerotic occlusion of the basilar artery (BA) with the left vertebral artery (VA) stenosis.

Case Presentation: An 80-year-old woman was brought to our hospital with progressively worsening consciousness and tetra-paresis. MRA revealed occlusion of the middle to proximal portion of the BA. The patient underwent percutaneous transluminal angioplasty using a balloon catheter for severe stenosis at the origin of the left VA, followed by mechanical thrombectomy for the BA occlusion. While initial recanalization was achieved, residual stenosis in the proximal portion of the BA led to re-occlusion. An attempt at angioplasty with a balloon catheter failed to reach the stenotic segment due to stenosis and tortuosity of the left VA. Consequently, the SR was redeployed into the BA, and a loading dose of antiplatelet agents and intravenous anticoagulant were administered during prolonged deployment. Following the confirmation of BA patency, the SR was re-sheathed and removed. The patient achieved remarkable improvement in consciousness and tetra-paresis without postoperative re-occlusion of the BA.

Conclusion: Angioplasty with a SR and combined antithrombotic therapy may be a useful treatment option for ICAD-related LVO, particularly in cases such as tandem lesions that hinder access and make distal balloon catheter navigation challenging.

Objective: Reversible cerebral vasospasm syndrome (RCVS) is characterized by multiple reversible convulsions of the cerebral arteries, accompanied by recurrent, thunderclap-like headaches. The prognosis of most patients is favorable; however, extensive cerebral infarction may result in significant disability or mortality in approximately 5% of cases. Endovascular treatment may be a therapeutic option for patients who do not respond to medical therapy. However, there is a paucity of detailed studies addressing this procedure.

Case Presentation: A 33-year-old woman presented with severe headache and elevated blood pressure during parturition, resulting in a decreased level of consciousness for 2 days postpartum. Head imaging revealed an intracerebral hemorrhage in the right caudate head nucleus and severe multiple stenoses of the cerebral vessels, leading to a diagnosis of RCVS. Despite treatment with verapamil and magnesium, complete paralysis of both lower limbs, the right upper limb, and aphasia developed on postpartum day 8 (day P8). Nicardipine was injected into the bilateral internal carotid arteries (ICAs) and vertebral arteries, and balloon angioplasty was performed at the tips of the bilateral ICA. Symptoms recurred, and the same nicardipine injection was administered on days P9 and P10. Vasoconstriction gradually improved, no major cerebral infarction occurred, and the patient was able to walk (modified Rankin Scale score, 1) by day P90.

Conclusion: Despite medical treatment, there are cases of extensive cerebral infarction due to strong vasoconstriction, and the postpartum period is a risk factor. Endovascular treatment is an effective option for severe RCVS.

Objective: A ruptured aneurysm rarely causes a primary intraventricular hemorrhage. Cases of aneurysms concomitant with internal carotid artery occlusion are occasionally reported; however, no previous studies have described lateral posterior choroidal artery (LPChA)-associated aneurysms with internal carotid artery occlusion.

Case Presentation: We experienced a case of intraventricular hemorrhage caused by the rupture of an LPChA aneurysm associated with the collateral circulation of internal carotid artery occlusion. After a detailed preoperative imaging study, the embolization was successfully achieved using n-butyl-2-cyanoacrylate without new neurological deficits.

Conclusion: This case highlights the importance of knowledge of the functional anatomy of collateral anastomosis of the intraventricular choroidal arteries, which allowed safe and successful embolization of the aneurysm.

Objective: Two mechanical thrombectomy techniques are proposed for tandem occlusion of the anterior circulation: treating the extracranial carotid artery lesion first via an antegrade approach and treating the intracranial lesion first via a retrograde approach. Previous reports show that the retrograde approach has a shorter reperfusion time and a better prognosis, but re-occlusion of the intracranial lesion after recanalization may occur. We describe a case of tandem occlusion with repeated intracranial occlusions for mechanical thrombectomy using the retrograde approach and discuss possible countermeasures.

Case Presentation: A 94-year-old woman presented with acute cerebral ischemia due to tandem carotid T occlusion of the left internal carotid artery (ICA) and severe stenosis of the cervical carotid artery. Mechanical thrombectomy via a retrograde approach was performed using a stent retriever, resulting in complete recanalization of the anterior circulation through the ICA after 1 pass. The thrombus dispersed distally from the cervical artery and re-occluded the M1 twice, requiring thrombus re-retrieval each time.

Conclusion: The retrograde approach to tandem occlusion can result in repeated re-occlusion after recanalization of the intracranial lesion. Thrombi in cervical carotid lesions are usually fragile. Prior thrombus aspiration from the balloon guiding catheter at the carotid lesion may prevent re-occlusion after recanalization of the intracranial lesion without sacrificing the time advantage of early recanalization via the retrograde approach.

Objective: A right-sided aortic arch is a rare vascular anomaly, and neuroendovascular therapy through the right-sided aortic arch is extremely rare. Herein, we report the case of a patient with a right-sided aortic arch who performed a mechanical thrombectomy for medium-vessel occlusion.

Case Presentation: An 84-year-old woman could not respond to her family during a conversation at 8:50 am. She was brought to our hospital at 10:30 am on the same day. A diffusion-weighted image of head magnetic resonance imaging revealed a high-intensity area in the left temporal lobe. Head magnetic resonance angiography revealed a loss of the inferior trunk of the left middle cerebral artery. A mechanical thrombectomy was performed. The guiding catheter ascended on the right side from the midline, and the patient was considered to have a right-sided aortic arch. Selecting the left common carotid artery was difficult due to its unusual origin from the ascending aorta. Internal carotid angiography revealed left temporo-occipital artery occlusion. Mechanical thrombectomy was performed using Solitaire X 3× 20 mm (Covidien, Irvine, CA, USA), and recanalization was achieved. Contrast-enhanced chest and abdominal computed tomography revealed a right-sided aortic arch with an aberrant left subclavian artery. She was transferred to a recovery hospital with a modified Rankin Scale score of 1.

Conclusion: Understanding the branching patterns and classifications of the right-sided aortic arch is necessary for physicians performing mechanical thrombectomy.

Objective: Duplication of extracranial cerebral arteries is a rare anatomical variant, most commonly observed in the vertebral artery. However, duplication of the cervical internal carotid artery (ICA) is extremely rare. We present a unique case of a patient diagnosed with a right facial artery aneurysm, in whom a right duplicated ICA, ipsilateral persistent stapedial artery (PSA), and contralateral aberrant ICA were incidentally identified.

Case Presentation: A 56-year-old woman presented with a painless mass in the right lower jaw. Physical examination revealed a round, pulsatile mass. Contrast-enhanced CT demonstrated a 25 mm saccular aneurysm originating from the right facial artery, along with a right duplicated ICA and a left aberrant ICA. The lateral limb of the right duplicated ICA and the left aberrant ICA were seen traversing the tympanic cavity and entering the carotid canal. The absence of the right foramen spinosum indicated the presence of a PSA. Angiography confirmed the duplicated ICA, aberrant ICA, and PSA. The lateral limb of the right duplicated ICA gave rise to the occipital artery and a small branch, the PSA, which entered the middle cranial fossa. The facial artery aneurysm was successfully embolized. Follow-up MR angiography showed stable occlusion of the aneurysm, with the duplicated ICA giving off both the PSA from the lateral limb and a pharyngeal branch from the medial limb.

Conclusion: This case provides valuable insights into the development of the cervical arterial system during the fetal period, particularly the collateral pathways connecting the third arch to the dorsal aorta.

Objective: The Leonis Mova (SB-Kawasumi Laboratories, Kanagawa, Japan) is a steerable microcatheter with a hand-operated dial that can be used to adjust the angle of the catheter tip. This steerable microcatheter has predominantly been used as an intermediate catheter. Herein, we report a case in which an aneurysmal subarachnoid hemorrhage was treated with coil embolization using the Leonis Mova microcatheter.

Case Presentation: A 53-year-old woman was transferred to our hospital for the treatment of a sudden onset of headache and vomiting caused by a subarachnoid hemorrhage detected on CT. DSA showed a 7.5-mm left internal carotid artery–posterior communicating artery aneurysm with multiple blebs, which we treated with coil embolization under general anesthesia. After placement of a 7-Fr guiding sheath in the left internal carotid artery, we introduced the Leonis Mova Selective microcatheter and the Excelsior SL-10 microcatheter (Stryker, Kalamazoo, MI, USA) into the center of the aneurysm. We inserted 9 coils into the aneurysm via the double-catheter technique, during which we adjusted the angle of the Leonis Mova microcatheter to fill each bleb in a piecemeal fashion. Almost complete obliteration was achieved, and the patient was ambulatory and discharged after completing treatment for the vasospasm phase of a subarachnoid hemorrhage.

Conclusion: The Leonis Mova may be a useful microcatheter for coil embolization of aneurysms with multiple blebs and a tortuous parent artery.

Objective: Endovascular treatment of cerebrovascular diseases can be challenging in patients with difficult access routes. We describe a turn-over technique using a balloon guiding catheter (BGC) via the transfemoral approach to perform neuroendovascular treatment.

Case Presentation: An 80-year-old female with a recurrent right middle cerebral artery (MCA) aneurysm after coil embolization underwent successful stent-assisted coiling via the transfemoral approach. The turn-over technique using a BGC proved effective for the difficult access route via the transfemoral approach. The guidewire and inner catheter were turned over above the aortic valve, and the BGC was advanced to the right subclavian artery. The guiding balloon was inflated, and the catheter shaft was pulled to release the loop on the aortic valve. Under roadmap guidance, the guidewire and inner catheter were advanced into the right internal carotid artery (ICA). After that, by using the balloon inflation anchoring technique, we carefully guided them to the right cervical ICA while preventing slippage.

Conclusion: The turn-over technique using a BGC via the transfemoral approach may offer a viable treatment option for patients with difficult vascular access.

Objective: Mirror image aneurysms located in the bilateral distal anterior cerebral arteries (ACAs) present significant technical challenges for both microsurgical and endovascular treatment due to their close proximity. To address these complexities, this technical note aims to describe a stepwise endovascular strategy for treating complex bilateral distal ACA kissing and mirror image aneurysms, highlighting key technical modifications such as preemptive bilateral stent deployment and selective microcatheter angiography.

Case Presentation: A woman in her 60s presented with bilateral distal ACA mirror image aneurysms (right: 10 mm; left: 7 mm). Endovascular treatment was indicated due to their high-risk morphology and a family history of subarachnoid hemorrhage. To overcome anticipated challenges, a stepwise stent-assisted coil embolization strategy was employed. Key steps included preemptive bilateral Neuroform Atlas stent (Stryker, Kalamazoo, MI, USA) deployment validated by cone-beam CT before any coiling, and selective angiography via a microcatheter left in the proximal A2 segment to ensure clear visualization during coil embolization. The procedure was completed without complications, with no recurrence observed at 5-year follow-up.

Conclusion: The stepwise endovascular strategy, which incorporated preemptive bilateral stent deployment prior to any coiling and utilized selective angiography via microcatheter, enabled the safe and effective endovascular treatment of these complex bilateral distal ACA mirror image aneurysms. This technical strategy offers a practical reference for the endovascular management of similarly complex and anatomically constrained aneurysms.

Objective: The snare-assisted stabilization technique can address difficult catheter access in cases such as type III aortic arch. This technique can provide additional support to the treatment system, and it has received attention again in the current era of distal access catheter. Because there are a limited number of reports on this technique, the current study showed the details of this technique and also evaluated the usefulness and safety of the snare-assisted stabilization technique.

Case Presentation: This is a retrospective observational study at a single center. The consequent cases using the snare-assisted stabilization technique from November 2016 to December 2024 were retrospectively reviewed. The main endpoints were morbidity, mortality rate at discharge, and the success ratio of treatments using this technique. This study included 20 patients. The patients’ median age was 73 years, and 70% (n = 14) were men. The primary causes of difficult catheter access included torturous or narrow vertebral artery (n = 13, 65%), type III aortic arch (n = 5, 25%), and short-segment common carotid artery proximal to the lesion (n = 2, 10%). The snare-assisted stabilization technique consistently facilitated improved support, resulting in successful procedures in all cases. In 95% (n = 19) of the cases, the procedures were completed without complications.

Conclusion: The snare-assisted stabilization technique is effective and safe for improving the guiding system support and addressing catheter access challenges. This technique should come back into the spotlight in the era of distal access catheters.

Objective: LEONIS Mova high-flow type (SB-KAWASUMI LABORATORIES, Kanagawa, Japan) is a steerable microcatheter that enables angle adjustment of the catheter tip using a hand-operated dial, and available as a coaxial microcatheter system with a 1.6-F microcatheter. It was used to navigate an occluded inferior petrosal sinus (IPS) in a patient with cavernous sinus (CS) dural arteriovenous fistula (AVF).

Case Presentation: A man in his 50s presenting with right eye congestion was diagnosed with dural AVF of the CS with bilateral occluded IPSs. The shunted pouch was located in the medial-lateral part of the right CS, with drainage into the superior ophthalmic vein. Transvenous embolization (TVE) from the femoral vein via the occluded IPS was performed. A 6-F guiding catheter was navigated to the right internal jugular vein, and LEONIS Mova high-flow type combined with a 1.6-F Carnelian MARVELS S microcatheter (Tokai Medical Products, Aichi, Japan) was navigated to the occluded IPS. The LEONIS Mova successfully engaged the IPS, and its tip was fixed by adjusting the curve. The microcatheter advanced smoothly into the right CS. After releasing the fixation of the LEONIS Mova, the microcatheter was advanced further into the CS, where the LEONIS Mova was once again fixed. The microcatheter was easily navigated to the shunted pouch, and targeted coil embolization of the shunted pouch, achieving complete occlusion of the dural AVF.

Conclusion: The LEONIS Mova steerable catheter offers flexible angle adjustment and strong support for catheter navigation within an occluded IPS during TVE for CS-dural AVF.

Objective: Mechanical thrombectomy (MT) for acute ischemic stroke usually requires blind procedures when endovascular devices are advanced into the occluded vessels. Therefore, the visualization of occluded vessels could potentially achieve safer procedures, shorter procedural time, and progression of the reperfusion rate. We report on the usefulness of a novel technique in which a 3D roadmap of occluded vessels was created from a rapid 3D proton density-weighted (PDW) variable refocusing flip angle and turbo spin echo (VRFA-TSE) method.

Case Presentation: 3D PDW VRFA-TSE imaging was performed in addition to routine MRI for 2 patients with middle cerebral artery occlusion. With the adjustments to the imaging parameters, we were able to perform 3D PDW imaging in less than 1 minute. Subsequently, a 3D image of the occluded vessels was constructed from these images. To create a 3D roadmap, the 3D PDW images were positioned with cone beam CT images obtained before MT using 3D-3D fusion. Because a neurological technician performed the imaging processing while doctors and nurses prepared for MT, practical loss time was approximately 2 minutes. MT was performed with reference to the 3D roadmap, and the occluded lesion was recanalized without complications in both patients. The 3D roadmap of the occluded vessels was well-matched with the recanalized vessels.

Conclusion: A 3D roadmap created from rapid 3D PDW imaging is a useful assistance technique for MT that allows the visualization of occluded vessels.

Objective: The Woven EndoBridge (WEB; MicroVention TERUMO, Tustin, CA, USA) is an intrasaccular flow disruptor developed for the treatment of wide-neck bifurcation aneurysms (WNBA). While its safety and satisfactory mid- to long-term treatment outcomes have been documented, there have also been reports of complications such as WEB protrusion and migration. We encountered 3 cases in which the WEB protruded or migrated to the parent vessel after deployment, necessitating retrieval. In this report, we address the technical tips for retrieval techniques and factors associated with these complications, including a literature review.

Case Presentation: Of the 120 cases of our experience with WEB treatment for cerebral aneurysms for the period since January 2021, 3 required WEB retrievals. In 2 cases, significant WEB migration toward the parent vessel occurred while maneuvering the delivery microcatheter because of sticky detachment. In the remaining case, after detachment of the WEB, tilting occurred, leading to a strong protrusion into one of the branches, which prevented guiding the microcatheter for bailout stenting. In all cases, the proximal marker of the WEB was captured using an Amplatz Goose Neck Microsnare (Medtronic, Minneapolis, MN, USA) pulled back into the VIA catheter (the delivery catheter for the WEB; MicroVention TERUMO), and further into an intermediate catheter positioned as close to the aneurysm as possible, enabling uneventful retrieval.

Conclusion: None of the cases damaged the aneurysm or proximal parent vessel wall, and additional aneurysm occlusion treatment was performed. However, WEB protrusions and migration are rare. When retrieval is required, it is crucial to act swiftly owing to the risk of distal thrombosis from the lumen inside of the WEB. Therefore, recognizing Goose Neck Microsnare as a retrieval technique is valuable.

Objective: This report describes the creation of a freestanding cerebrovascular model with an attached Luer valve device and a bridge.

Case Presentation: A left internal carotid artery aneurysm was discovered during a detailed examination of headaches in a 70-year-old woman. A vascular lumen model was created for the pretreatment simulation. The addition of a male Luer valve and bridge to the vascular lumen model created using the multistep vascular wall thickness method facilitated lumen washing, support material removal, self-support, and compatibility with medical devices.

Conclusion: By adding Luer valves and struts and creating cerebral vascular lumen models with appropriate vessel wall thicknesses, we can enhance their efficiency, strength, and utility in preoperative simulations.

Anterior cranial fossa (ACF) dural arteriovenous fistula (DAVF) is a rare lesion among cerebral DAVFs. This lesion shows significant bleeding risk because of the angioarchitecture, involving direct leptomeningeal retrograde venous drainage, as a nonsinus-type DAVF. Over the years, direct surgery has been considered the primary treatment for ACF DAVF, offering favorable clinical outcomes compared to a low complete obliteration rate with endovascular treatment and the relatively high risk of blindness due to central retinal artery occlusion with transophthalmic artery embolization. In recent years, however, significant improvements in DSA and 3D reconstruction imaging quality have allowed a much more precise understanding of the angioarchitecture of the shunt and vascular access route. In addition, advances in endovascular devices, including catheters and embolic materials, have facilitated microcatheter navigation into more distal vessels and more reliable closure of the fistulous point. Supported by such technological innovations, endovascular approaches to the treatment of ACF DAVF have been becoming successful first-line treatments. This article reviews the evolution of treatment strategies and the current status of endovascular treatment for ACF DAVF, with a particular focus on transarterial embolization.

The sphenoid wing dural arteriovenous fistulas (DAVFs) are clinically rare. They often present as non-sinus-type arteriovenous fistulas (AVFs) and may be associated with focal neurological deficits, intracranial venous hypertension, and intracranial hemorrhage. These cases are classified as lesser or greater sphenoid wing lesions. We searched the PubMed databases for studies evaluating the clinical presentation, surgical treatment, and endovascular treatment of these lesions and analyzed 37 cases from 22 papers. A total of 17 cases had lesser sphenoid wing AVFs, and the localization of the shunts could be divided into the sinus of the lesser sphenoid wing (SLSW) or the superficial middle cerebral vein (SMCV). Most SLSW AVFs drained into the cavernous sinus, but two cases drained directly into the deep middle cerebral vein via a bridging vein. All cases with shunts directly into the SMCV had reflux into the SMCV with varices. A total of 20 cases had shunts in the greater sphenoid wing, and the localization of the shunts varied, with shunt localization, and venous return morphology dependent on variations in middle fossa venous return. Most cases had shunts in the sphenobasal vein near the foramen ovale. However, some cases had shunts in the superior ophthalmic vein, sphenopetrosal vein, and laterocavernous sinus. Many were associated with cortical venous reflux. These lesions have been treated by surgical ligation of the drainage vein and transarterial or transvenous embolization. Recently, embolization has become the standard treatment for DAVFs due to advances in endovascular techniques. This paper reviewed and discussed the angioarchitecture, clinical presentation, and treatment of these lesions to clarify the characteristics of sphenoid wing DAVFs.

Dural arteriovenous fistula (dAVF) of the foramen magnum (FM) region is rare. Moreover, the terminology of dAVF is very confusing in this region. In the narrow sense, the FM dAVF is the non-sinus-type dAVF with direct venous reflux to the medulla oblongata or spinal cord via the bridging veins (BVs) of the FM. Previous literature was systematically reviewed to investigate the clinical characteristics, angioarchitecture, and effective treatment of the FM dAVF. From the literature review, almost all the feeders of FM dAVF were dural branches. Spinal pial arteries were rarely involved as the feeder. All lesions had venous reflux to the medulla oblongata via medullary BVs. The FM dAVF is characterized by a significant male predominance and a high incidence of aggressive symptoms. The most common symptom is congestive myelopathy, followed by hemorrhage. The FM dAVF differs from the craniocervical junction (CCJ) arteriovenous fistula (AVF) and is similar to the thoracolumbar spinal dAVF. Direct surgery for the FM dAVF is effective and safe. Endovascular treatment for the FM dAVF may be more effective and has lower complication rates than that for the CCJ AVF.

The clinical manifestations of dural arteriovenous fistulas (dAVFs) are highly variable and dependent on the hemodynamic properties and location of the fistula. The locations of the fistula are numerous and include the cavernous sinus, transverse–sigmoid sinus, superior sagittal sinus, inferior and superior petrosal sinuses, anterior condylar confluence, tentorium, anterior cranial fossa, middle fossa, foramen magnum, cranio-cervical junction, convexity, and spinal cord. These dAVFs can be divided into two types, “sinus type” and “non-sinus type,” based on their communication with dural shunts and cerebral veins. The sinus type involves direct communication between the arterial dural branch and one dural sinus, sometimes leading to recruitment of cortical veins. On the other hand, the non-sinus type is embedded into the dura, with the drainage always involving a cerebral vein and no communication with any sinus. Treatment options for these types of dAVFs differ; sinus-type dAVFs require normally sinus obliteration and occlusion of recruited veins, while non-sinus-type dAVFs require embolization of the drainage vein. Accurately classifying the type of fistula, sinus type or non-sinus type, is critical for developing a proper treatment plan. This review describes clinical characteristics and treatment of those non-sinus-type dAVFs involving unusual locations with illustrative cases.

Acute coronary syndrome (ACS) encompasses a spectrum of cardiovascular emergencies, including unstable angina and myocardial infarction, that require immediate and effective management to reduce morbidity and mortality. Antithrombotic therapy, including antiplatelet and anticoagulant medications, is fundamental in ACS management. We sought to organize the current status of antithrombotic management of ACS, including the concept of high bleeding risk (HBR), in line with the clinical diagnostic flow. ACS is an ever-changing condition; therefore, its diagnosis and treatment are conducted in parallel. While primarily a coronary artery disease, the diagnosis of ACS also includes conditions such as myocardial infarction with nonobstructive coronary arteries as a working diagnosis. This review collates the mechanisms and classification of ACS, showing the diagnostic flow and the antithrombotic agents used at each stage. It discusses strategies for dual antiplatelet therapy (DAPT) duration and de-escalation in patients undergoing percutaneous coronary intervention and addresses the management of patients requiring oral anticoagulation alongside antiplatelet therapy, highlighting the shift toward dual therapy to reduce bleeding risk. Antithrombotic agents are key treatments for ACS, with various available options. Their mechanisms and the approved dosing regimens differ regionally, especially between Japan and other countries. This review synthesizes the regional availability of each agent and compares the latest recommendations from Japanese and international guidelines for ACS management. The field of antithrombotic therapy in ACS is dynamic, influenced by the findings of ongoing clinical trials and emerging evidence. Key considerations include balancing antithrombotic benefits against bleeding risks, particularly in patients with HBR. Recent studies have explored shorter DAPT durations and novel antithrombotic agents, offering new insights for diverse patient populations. In this review, we provide a comprehensive comparison of guidelines and insights from the neuro-interventional field to assist clinicians in making informed decisions regarding ACS management. As ACS management evolves, continued international, cross-sectional collaboration and research are essential to refine guidelines and improve clinical practice.

Antithrombotic therapy plays a crucial role in secondary prevention following ischemic stroke from the acute phase. Numerous trials, along with a meta-analysis, contributed to establishing aspirin as the primary medication for secondary stroke prevention. According to the Cochrane Database of Systematic Review 2022, initiating antiplatelet therapy with aspirin at a dose of 160 mg to 300 mg daily within 48 hours of stroke onset reduces the risk of death or dependency at the end of follow-up. Other antiplatelet drugs, such as clopidogrel, cilostazol, prasugrel, and intravenous ozagrel sodium, are also available within the Japanese Health Care Insurance System. Two pivotal trials from the 2010s underscored the effectiveness and safety of dual antiplatelet therapy (DAPT) using aspirin and clopidogrel, administered for 21 days to 3 months following acute ischemic stroke or transient ischemic attack. However, the extension of DAPT with aspirin and clopidogrel beyond 3 months may result in substantial bleeding risks. Although prasugrel offers a rapid, potent, and consistent inhibition of platelet aggregation and can be used in place of clopidogrel, there is a lack of substantial real-world clinical data on its use in acute ischemic stroke. It is important to recognize that antiplatelet drugs might not be beneficial and could even increase the risk of hemorrhagic events in cardioembolic stroke. In cases of ischemic stroke with nonvalvular atrial fibrillation, direct oral anticoagulants are the primary choice if applicable. Warfarin continues to be the anticoagulant of choice for secondary stroke prevention in patients with mechanical valve replacements. In patients who have undergone intravenous thrombolysis, antithrombotic therapy is generally delayed for up to 24 hours, although there are no definitive guidelines for the period during and immediately after mechanical thrombectomy. This review provides an overview of the current status of antithrombotic therapy for acute ischemic stroke.

Optimal platelet inhibition is critical in patients with carotid and intracranial artery stenosis undergoing carotid artery stenting (CAS) and intracranial artery stenting (ICS). Many reports have highlighted the importance of dual antiplatelet therapy (DAPT) in reducing adverse neurological outcomes without a significant increase in bleeding complications during CAS. DAPT has commonly used CAS and ICS, typically with aspirin and clopidogrel, but clopidogrel resistance occurs in approximately 20% of Japanese and other Asian populations. One solution to clopidogrel resistance is using adjunctive cilostazol to suppress the frequency of stroke events and in-stent restenosis after CAS. Other antiplatelet agents such as prasugrel, ticagrelor, cangrelor, and glycoprotein (GP) IIb/IIIa inhibitors are under investigation. The duration of DAPT after CAS remains controversial, as a longer duration of DAPT after CAS is associated with lower rates of readmission for stroke, but increased risk of hemorrhagic complications. Regarding antithrombotic therapy in CAS with concomitant atrial fibrillation, the use of direct oral anticoagulants plus a P2Y12 inhibitor may be suggested for the optimal safety and efficacy of antithrombotic management. For emergent CAS in acute ischemic stroke (AIS), intraprocedural DAPT loading and GP IIb/IIIa inhibitors, as necessary, may improve stent patency without increasing the risk of intracranial hemorrhage. In ICS, aggressive antiplatelet therapy based on an assessment of platelet aggregation is also important to improve clinical outcomes. In addition, rescue stenting for AIS caused by intracranial atherosclerotic stenosis-related large vessel occlusion is gaining attention. GP IIb/IIIa inhibitors have shown promise, but are not approved in Japan. In conclusion, DAPT is essential for the perioperative management of CAS and ICS. Specific perioperative antithrombotic management remains unclear, but the potential benefits of antithrombotic agents must be weighed against the corresponding increased risk of bleeding complications.

Thromboembolism is one of the main causes of severe complications in the endovascular treatment of cerebral aneurysms, and antiplatelet therapy (APT) is necessary to prevent such complications. Conversely, prolonged APT has the potential risk of hemorrhagic complications; therefore, the timing of dose reduction or discontinuation is an important aspect of periprocedural APT. However, no clinical evidence of an optimal regimen of APT for cerebral aneurysms exists, and the selection, dosage, duration, or combination of antiplatelets has been dependent on physicians for unruptured or ruptured cerebral aneurysms. Many reports have shown that preoperative APT can reduce ischemic complications without increasing hemorrhagic complications, and some reports have shown that the P2Y12 reaction unit (PRU) value measured using the VerifyNow (Werfen, Barcelona, Spain) system is associated with periprocedural ischemic and hemorrhagic complications. Appropriate dose and duration management adjustments based on the platelet reactivity test, aneurysm morphology, treatment, and patient background may contribute to good outcomes. Although accumulating evidence exists regarding the efficacy of preoperative APT, there is no evidence regarding the optimal duration or discontinuation of APT.

Brain arteriovenous malformations (AVMs) are intricate networks of blood vessels in which arteries connect directly to veins, bypassing the capillary system. This aberration can lead to serious neurological manifestations, including seizures, headaches, and hemorrhagic strokes. The embryonic development of AVMs implicates possible disruptions in arteriovenous differentiation during angiogenesis, improper regression of the primary capillary plexus, or the retention of fetal vasculature as contributing factors. Additionally, genetic mutations and environmental influences during pregnancy may facilitate AVM formation, with identified mutations in genes such as endoglin, activin receptor-like kinase 1, SMAD family member 4, and RAS p21 protein activator 1 disrupting vascular development. Such mutations are associated with conditions like hereditary hemorrhagic telangiectasia and capillary malformation-arteriovenous malformation syndrome, thus highlighting the essential role of genetic counseling in AVM management. This review underscores the importance of a deep comprehension of the embryological and genetic foundations of AVMs to refine diagnostic, therapeutic, and prognostic approaches. The paper advocates for advanced research on intervention strategies and emphasizes the significance of a genetics-focused approach in the clinical management of AVMs.

Brain arteriovenous malformations (bAVMs) are associated with a high risk of intracerebral hemorrhage, which causes severe complications in patients. Although the genetic factors leading to hereditary bAVMs have been extensively investigated, their pathogenesis are still under study. This review examines updated data on the molecular and genetic aspects of bAVMs, the architecture of microvasculature, the roles of angiogenic factors, and signaling pathways. The compiled information may help us understand the pathogenesis of both sporadic and hereditary bAVMs and develop appropriate preemptive treatment approaches.

Objective: The authors aimed for a systematic review to clarify the current role of transarterial embolization (TAE) in the management of brain arteriovenous malformations (BAVMs).

Methods: A search was conducted on PubMed, using the following terms; “brain arteriovenous malformation,” “cerebral arteriovenous malformation,” “endovascular treatment,” and “transarterial embolization.” Studies reporting the efficacy and safety of endovascular treatment for BAVMs, performed either as a standalone treatment or in conjunction with surgery or radiosurgery, were included. The final search was conducted in December 2023. Only articles written in English were reviewed. The references of publications of interest were also screened. Studies on transvenous embolization were excluded. More than 100 articles on the treatment of BAVMs were reviewed.

Results: Advances in endovascular techniques and devices have enabled TAE as a treatment modality for BAVMs, to achieve higher embolization rates. Thus, curative TAE for some BAVMs with suitable angioarchitecture has become possible. The efficacy of presurgical TAE in the treatment of low Spetzler-Martin grade BAVMs is limited; however, TAE is effective for intermediate grade BAVMs. Several reports using propensity-matched analyses reevaluated the therapeutic efficacy of pre-/post-radiosurgical TAE for BAVMs with radiosurgery-resistant lesions such as large nidus, fistulous components, and associated aneurysms. The complication rate of TAEs as a treatment modality for BAVMs is approximately 10%, and hemorrhagic complications occur in approximately 5% of cases. Despite recent advances, substantial improvements have not been observed in the morbidity and mortality associated with TAEs for the treatment of BAVMs.

Conclusion: TAE for the treatment of BAVMs is primarily performed in an adjuvant manner; however, recent advances have made standalone embolization possible. A multidisciplinary team should evaluate each case independently. Furthermore, as per recent studies, inclusive of meta-analyses, the efficacy and safety of TAEs for the treatment of BAVMs have not been elucidated. Thus, the manifestations and characteristics of BAVMs, in addition to the objective of performing a TAE, should be deliberated carefully before the endovascular procedure, to avoid complications.

Brain arteriovenous malformations (bAVMs) are uncommon vascular lesions found in young individuals exhibiting diverse clinical manifestations ranging from asymptomatic to spontaneous intracranial hemorrhage, seizures, or headaches. Despite improvements in endovascular tools and methods, standalone transarterial embolization seldom achieves success rates surpassing 50%, even when employing ethylene vinyl alcohol copolymers. Transvenous embolization (TVE) emerges as a promising option, especially for bAVMs situated distally or inaccessible through arterial routes. Despite the possibility of achieving high angiographic cure rates, concerns regarding hemorrhagic complications persist, limiting its adoption. This review article outlines the indications and methodology of TVE, discusses complications, and highlights the essential expertise needed for the safe execution of TVE along with strategies to mitigate associated risks. Clinical results reveal promising outcomes in terms of obliteration rates and favorable neurological results, although challenges persist, particularly regarding device accessibility and risk management. Despite these challenges, TVE remains a valuable alternative for managing bAVMs, particularly for cases resistant to surgical intervention, emphasizing the significance of careful patient selection and procedural expertise.