Objective: The first pass effect (FPE), which means the achievement of complete or near-complete reperfusion of large vessel occlusion (LVO) in the first pass, is one of the goals of mechanical thrombectomy (MT). However, the impact of FPE on the prognosis has not been assessed for Japanese patients with various degrees of independence before the onset of LVO. The purpose of this study was to investigate the prognostic effects of FPE in a comprehensive stroke center in Japan, which includes patients in a variety of self-independence states with different comorbidities before stroke onset.

Methods: Between April 2017 and March 2020, 151 patients who underwent MT with a stent retriever (SR) alone as initial strategy for anterior circulation (internal carotid artery terminal, M1, M2) LVO at our hospital and finally achieved modified treatment in cerebral infarction (mTICI) 2b–3 were analyzed. Forty-eight patients in whom first pass mTICI 2c–3 was achieved were classified into the FPE+ group, and the other 103 patients were classified into the FPE– group. We compared the characteristics and clinical outcomes between patients with and without FPE, and estimated the odds ratio for outcomes after adjusting for confounders.

Results: The puncture–reperfusion time was shorter (20 vs. 35 minutes; p <0.01), and cardiogenic embolism was more common (81.3 vs. 60.2%; p = 0.01) in the FPE+ group. The FPE was significantly associated with good neurological outcome after 3 months (p <0.01; adjusted odds ratio [aOR], 3.87; 95% confidence interval [CI], 1.69–9.38), reduction in all intracranial hemorrhage (p <0.01; aOR, 0.24; 95% CI, 0.10–0.54), and symptomatic intracranial hemorrhage (p = 0.04; aOR, 0.16; 95% CI, 0.01–0.98).

Conclusion: The FPE with an SR alone improved the neurological prognosis in a Japanese patient group.

Objective: In various fields, differences in eye-gazing patterns during tasks between experts and novices have been evaluated. The aim of this study was to investigate gazing patterns during neuro-endovascular treatment using an eye-tracking device and assess whether gazing patterns depend on the physician’s experience or skill.

Methods: Seven physicians performed coil embolization for a cerebral aneurysm in a silicone vessel model under biplane X-ray fluoroscopy, and their gazing patterns were recorded using an eye-tracking device. The subjects were divided into three groups according to experience, highly experienced (Expert) group, intermediately experienced (Trainee) group, and less experienced (Novice) group. The duration of fixation on the anterior–posterior (AP) view screen, lateral (LR) view, and out-of-screen were compared between each group.

Results: During microcatheter navigation, the Expert and Trainee groups spent a long time on fixation to AP, while the Novice group split their attention between each location. In coil insertion, the Expert group gazed at both the AP and the LR views with more saccades between screens. In contrast, the Trainee group spent most of their time only on the AP view screen and the Novice group spent longer out-of-screen.

Conclusion: An eye-tracking device can detect different gazing patterns among physicians with several experiences and skill levels of neuroendovascular treatment. Learning the gazing patterns of experts using eye tracking may be a good educational tool for novices and trainees.

Objective: We report a rare case of a patient with a ruptured posterior communicating artery (P-com A) dissecting aneurysm and chronic kidney disease (CKD) treated by endovascular embolization using a small amount of contrast medium.

Case Presentation: An 88-year-old female patient had sudden onset of headache and vomit due to subarachnoid hemorrhage. MRI revealed a ruptured dissecting aneurysm of the right P-com A. The patient had CKD of severity grade 4. Endovascular treatment was performed using only 10 mL of diluted contrast medium with injection through a microcatheter. The postoperative course was uneventful, and no deterioration of renal function occurred.

Conclusion: With minimal amount of contrast medium, endovascular treatment could be safely and effectively performed for patients with P-com A dissecting aneurysms and severe CKD.

Objective: Ruptured carotid-cavernous aneurysms (CCAs) are known to result in direct carotid-cavernous fistula (CCF). Although endovascular treatment is recognized as the first-line treatment for direct CCF, obliteration is sometimes difficult because of the high-flow shunt. In this report, we present a case of a direct CCF treated by the combination of transarterial and transvenous approaches.

Case Presentation: A 57-year-old woman presented with conjunctival chemosis, exophthalmos, and tinnitus. Ophthalmological examination revealed increased intraocular pressure. DSA demonstrated a direct CCF due to a right ruptured CCA with retrograde shunted flow through the superior ophthalmic vein (SOV), superficial middle cerebral vein, basal vein of Rosenthal, and middle temporal vein. Two microcatheters were guided into the shunt segment from the internal carotid artery and SOV. In addition, a balloon catheter was placed at the neck of the aneurysm to assist coiling. Coil embolization for the CCF was performed using two microcatheters in the opposite direction, which enabled compact and tight packing of the shunt segment with only six coils. The CCF was eliminated. Two-year-follow-up MRA revealed no recurrence.

Conclusion: The bidirectional double catheter technique is a useful approach to obliterate a shunt in a short segment with minimal coils.

Objective: Morphologically challenging cerebral aneurysms cannot be treated through standard endovascular procedures. We report two cases of ruptured aneurysms treated using coils and n-butyl cyanoacrylate (NBCA).

Case Presentations: Case 1 was an 80-year-old woman diagnosed with a subarachnoid hemorrhage (SAH). An angiogram revealed a large and wide-necked basilar artery bifurcation aneurysm. Bilateral superior cerebellar and posterior cerebral arteries (PCAs) originated from the aneurysmal wall. A 3-mm-diameter bleb was detected on the aneurysmal fundus. The bleb enlarged 1 month following coil insertion. During the second treatment, we infused a small volume of 33% NBCA into the coil-framed bleb following proximal flow control of the bilateral vertebral arteries (VAs). The complete bleb obliteration was confirmed by the angiogram at 6 months later. The coil shape was followed up via plane X-ray for 5 years. No rebleeding occurred. Case 2 was a 41-year-old woman diagnosed with SAH. An angiogram revealed a dissecting aneurysm of the left PCA (P1 and P2 segments) accompanying a bleb on the P1 segment. Endovascular treatment was performed, and a coil was inserted into the bleb, infusing 33% NBCA into the coil frame following proximal flow control of bilateral VAs and the right internal carotid artery. Angiograms conducted at 3 months, 1 year, and 9 years and an MRA conducted 12 years later revealed a lack of bleb recanalization.

Conclusion: We developed a Coil and NBCA technique to obliterate ruptured blebs following proximal flow control. This technique can be considered an effective alternative for treating morphologically challenging cerebral aneurysms.

Objective: Coil unraveling is a rare, yet dangerous complication of endovascular coiling. In this study, we report a patient in whom an intraoperatively unraveled coil was successfully retrieved using a KUSABI exchange catheter, which is used in the field of cardiovascular medicine to facilitate catheter exchange in coronary interventions.

Case Presentation: The patient was a 90-year-old woman. To treat an unruptured aneurysm of the right internal carotid artery, endovascular coil embolization was performed. During the filling step, the coil started to unravel. Early attempts to retrieve the unraveled coil using a microsnare were complicated when the ensnared part broke off during the process. The broken tip of the unraveled coil was maneuvered inside the guiding catheter, after which a KUSABI catheter was inflated inside the guiding catheter to press and immobilize the unraveled coil against its inner lumen. This fragment of the unraveled coil was extricated from the patient by retracting the entire guiding catheter assembly. We guided a microsnare along the remaining unraveled coil to capture the intact part of the coil, and eventually retrieval was successful.

Conclusion: To our knowledge, no study has reported retrieval with a KUSABI trapping balloon catheter for the management of coil unraveling. However, this method is considered effective. We report this case and review the literature.

Objective: There are few reports on endovascular treatment of tandem lesions in the posterior circulation and no consensus on treatment strategies has been reached. We report a case of tandem lesions of basilar artery occlusion and vertebral artery stenosis treated by thrombectomy and vertebral artery stenting.

Case Presentation: We present the case of a 73-year-old man who developed consciousness disorder and tetraplegia. Head and neck CTA revealed tandem left vertebral artery stenosis and basilar artery occlusion. The patient was treated using a reverse technique, which involves performing thrombectomy first and then vertebral artery stenting, along with Carotid Guardwire PS. Postoperative impairment of consciousness and improvement of tetraplegia were achieved.

Conclusion: The reverse technique combined with Carotid Guardwire PS may be a useful treatment strategy for tandem lesions in the posterior circulation.

Objective: We introduce a coil-assisted technique using a small diameter helical coil to preserve a branch artery in the aneurysm neck or dome during coil embolization of a cerebral aneurysm.

Case Presentations: We report three cases that were treated with the coil-assisted technique. Using this method, the branch artery was preserved with a small diameter helical coil that was placed to support another frame coil. The first case was a ruptured internal carotid artery–posterior communicating artery (IC–Pcom) aneurysm, the second case was a ruptured anterior communicating artery aneurysm, and the third case was an unruptured IC–Pcom aneurysm, with branching of the Pcom, A2, and Pcom, respectively, from the neck or dome of the aneurysm. We were able to preserve the branch artery in all cases.

Conclusion: This technique is feasible and safe for coil embolization of intracranial branch-incorporated aneurysms. The technique is especially useful for preserving branch arteries that are difficult to preserve by conventional techniques.