Objective: Early intervention with mechanical thrombectomy (MT) is expected to improve the functional outcome in patients with large vessel occlusion (LVO); however, a method for the effective detection of these patients in a prehospital setting and early transport to MT-capable hospitals has not been established. This study aimed to analyze the clinical impact and diagnostic performance of the emergent large vessel occlusion (ELVO) screen and its influence on the transportation time.

Methods: The emergency medical services (EMS) in one of the secondary medical areas in Akita, Japan, introduced a prehospital triage system employing an ELVO screen and a rotation system of three MT-capable hospitals on December 1, 2021. Patients who were transferred to each of the three hospitals involved in the rotation system according to a predefined priority list from December 2021 to November 2022 were included in the triage group. Patients who underwent MT in the three hospitals before the introduction of the triage system were assigned to the pre-triage group. We compared the transportation time parameters between the two groups and analyzed the performance of the ELVO screen for the diagnosis of LVOs. This study was approved by the institutional review boards of all three hospitals.

Results: Time parameters were compared between the 37 and 42 patients who underwent MT and had detailed data in the triage (n = 351) and pre-triage (n = 43) groups, respectively. The time from door to puncture tended to decrease in the triage group in all hospitals, with one hospital showing a statistically significant shortening of 14 min (p = 0.018). In the triage group, 209 ELVO screen-positive patients were present, with 60 (28.7%) of these having LVO. The sensitivity, specificity, positive and negative predictive values, and area under the curve of the ELVO screen to detect LVO under the present triage system were 87.0%, 47.2%, 28.7%, 93.7%, and 0.671, respectively.

Conclusion: The present study demonstrated that the introduction of a triage system may have shortened the time required for MT. ELVO screen may be considered a useful marker for screening LVO in prehospital settings in terms of the sensitivity and negative predictive value; however, further improvement may be necessary to reduce the rate of false positive results.

Objectives: The superiority and usefulness of liquid material over particles for embolization have been a topic of debate due to differences in materials and techniques. This study aimed to identify the complications and outcomes associated with both embolization materials.

Methods: This retrospective multicenter cohort study included 93 patients from an endovascular treatment registry, treated from January 1, 2018 to May 31, 2022. It included patients who underwent preoperative embolization for meningioma, solitary fibrous tumor/hemangiopericytoma, and hemangioblastoma. Data for patient characteristics, procedural factors, complications, and outcomes were collected from medical records.

Results: A tortuous access route was the only factor independently associated with complications (p = 0.020). Although liquid material was more frequently used for embolization in relatively high-risk conditions, complication rates did not differ significantly between the groups (p = 0.999). In the liquid material group, the tip of the microcatheter could be guided closer to the tumor (p <0.001) using a distal access catheter and flow-guide microcatheters. The subgroup middle meningeal artery embolization had less operative bleeding in the liquid material group (p <0.001), whereas the particles group exhibited less intraoperative blood loss than the liquid material group (p = 0.006).

Conclusion: The vascular tortuosity of the access route was only associated with complications in preoperative tumor embolization. Liquid material and particles showed no difference in complication rates. The use of particles in embolization may reduce intraoperative bleeding, but not in all cases can it be used safely. Therefore, a thorough understanding of the characteristics of both approaches and their relative advantages in clinical practice is essential to opt for the appropriate material according to the case.

Objective: Intraorbital dural arteriovenous fistula (IO-dAVF) is a rare condition, and treatment options vary from case to case. We report a case of transarterial embolization (TAE) for IO-dAVF.

Case Presentation: A 62-year-old male complained of gradually worsening pain, hyperemia, and visual impairment in the right eye. He did not exhibit diplopia or exophthalmos. Cerebral angiography revealed an arteriovenous fistula in the right orbit. The feeding arteries were the ophthalmic artery (OphA) and the artery of the superior orbital fissure (ASOF), with the superior ophthalmic vein (SOV) as the main draining vein. The venous pathway from the SOV was not clearly visible, and considering the risk of blindness with TAE from the OphA, TAE from the ASOF was performed. Onyx 18 was selected as the liquid embolic material and injected through a microcatheter placed in the internal maxillary artery. Occlusion up to the SOV was achieved, and the shunt flow completely disappeared. Normal blood flow in the OphA was maintained, hyperemia improved, and no complications were observed.

Conclusion: In cases of IO-dAVF, when transvenous embolization is difficult to perform, TAE using Onyx from the vessel of the external carotid artery system may be preferred over OphA.

Objective: Infection after carotid artery stenting (CAS) is rare. We report two dialysis cases of delayed stent infection associated with a carotid dual-layer stent (DLS), which occurred several months after deployment of the stent.

Case Presentations: Case 1: A 74-year-old man receiving dialysis underwent CAS with DLS. Three months after CAS, the patient developed a high fever, neck pain, and neck swelling. Neck CT and carotid ultrasonography (CUS) indicated an abscess around the inserted DLS. The patient was treated with antibiotic agents and fully recovered. Case 2: A 73-year-old man receiving dialysis underwent CAS with DLS. Two months after CAS, this patient also developed a high fever, neck pain, and neck swelling. Contrast-enhanced neck CT indicated inflammatory effusion with an abscess and a giant infectious pseudoaneurysm. Endovascular stent graft reconstruction was employed urgently under antibiotic therapy to prevent its rupture. However, intracranial hemorrhage occurred postoperatively and left hemiparesis remained.

Conclusion: Delayed carotid stent infection is a rare but severe complication. The use of a DLS might be avoided during CAS for dialysis cases.