Intracranial vertebral artery dissection (VAD) is the most common arterial dissection in intracranial arteries. Some types of VAD can heal spontaneously after reconstitution of the vessel lumen with excellent prognosis, whereas others can progress to stroke that needs treatment. Recently, endovascular treatment (EVT) has emerged and is suggested as a treatment option for VADs due to perceived low rates of procedure-related morbidity with good efficacy. In the last decade, we have accumulated our strategies to treat those VADs. Here, we try to share our experiences about VADs, including indications and methods of treatment of VADs using EVT. We perform EVT for ruptured VADs presenting with SAH and some of unruptured VADs such as VAD with recurrent or progressive ischemia, dissecting aneurysm larger than 7 mm or with mass effect, early ugly change of VADs in shape and size during follow-up period, involving the basilar artery (BA) and bilateral VADs. We present how we have done in our real practice for the last decade for treating VADs by EVT rather than reviewing and organizing so-far-published literature. We tended to occlude the rupture point by vertebral artery (VA) occlusion in non-dominant VA or stent-assisted coiling in dominant VA for ruptured VADs. We tended to reconstruct original hemodynamics using various stents for unruptured VADs. To decide what to treat and how to treat are very complicated for VADs. However, we believe that EVT is the current mainstay for treating VADs. Each technique of EVT should be determined on a case-by-case basis at the discretion of endovascular neurosurgeons and/or interventional neuroradiologists according to presenting symptoms, hemodynamic status, including sufficiency of the collateral supply and anatomic features of the vertebrobasilar artery as well as the posterior inferior cerebellar artery, anterior spinal artery, and medullary perforators.

Objective: The purpose of this study was to evaluate the combination of a 100-cm long balloon-guiding catheter (BGC) and 40-cm long sheath in patients treated by mechanical thrombectomy for anterior circulation acute ischemic stroke.

Methods: The subjects were 77 consecutive patients treated by endovascular recanalization for anterior circulation occlusion from January 2011. After February 2018, 24 patients were treated by mechanical thrombectomy using a long BGC and long sheath (L-BGC group), and were compared with 53 patients treated before January 2018 using a normal BGC and sheath (S-BGC group). The baseline angiographical/clinical characteristics, main procedures, BGC insertion time, internal carotid artery (ICA) cartelization rate, recanalization rate, and clinical outcome were compared between L-BGC and S-BGC groups.

Results: There was no significant difference in angiographical/clinical characteristics except for intravenous thrombolysis with recombinant tissue plasminogen activator (IVrtPA) treatment. In all, 22 patients were treated by combined technique (CoT) thrombectomy in the L-BGC group. The BGC insertion time was significantly shorter in the L-BGC group than in the S-BGC group (19 vs 13 minutes), and ICA catheterization of BGC was successful in the L-BGC group, whereas there were seven failures in the S-BGC group (100% vs 84%). The puncture-to-recanalization (PtoR) time was significantly shorter in the L-BGC group (90 vs 44 minutes). The successful recanalization (SR) rate was higher in the L-BGC group (96% vs 72%). Good outcomes (mRS 0-2) slightly increased in the L-BGC group (64% vs 49%). In the multivariable analysis, only CoT thrombectomy was associated with PtoR and SR.

Conclusion: The combination of a long BGC and long sheath results in rapid and stable BGC insertion to the ICA. CoT thrombectomy with these devices may be useful for SR and reducing the PtoR in anterior circulation mechanical thrombectomy.

Objective: The natural course of chronic carotid artery total occlusion (CTO) is poor. Previous reports suggested that carotid artery stenting (CAS) improves the clinical outcome of CTO. However, its long-term efficacy has not been established. This study assessed the mid- and long-term clinical outcome of CAS for CTO.

Methods: We evaluated the clinical outcome of 15 patients who underwent CAS for CTO between September 2010 and October 2019.

Results: The technical success rate of recanalization was 93.3% (14 of 15 patients). Eight patients were treated using self-expanding stents, and six were treated using self-expanding coronary stents. Symptomatic procedure-related complications developed in two patients (13.3%). During the follow-up period (mean 34.9 months), symptomatic ipsilateral stroke was not noted. One patient (7.1%) developed asymptomatic re-occlusion, but stent patency was preserved in 13 patients (92.9%).

Conclusion: CAS for CTO may be safe and feasible based on the mid- and long-term outcome.

Objective: The efficacy and safety of acute percutaneous transluminal angioplasty or stenting (PTA/PTAS) for vertebrobasilar artery occlusion with atherothrombotic brain infarction (ATBI) have not been confirmed despite the resistance to medical therapy alone. There are few reports about this disease and its treatment. Therefore, the treatment outcomes at our hospital were summarized to evaluate the efficacy and safety.

Methods: This was a retrospective study of acute PTA/PTAS for vertebrobasilar artery occlusion due to atherosclerotic change in 19 consecutive patients with a modified Rankin Scale (mRS) score of 0-2 before stroke between March 2010 and December 2018. The factors related to prognosis were investigated. Outcomes were assessed at 90 days of follow-up.

Results: Of 19 patients with acute vertebrobasilar artery occlusion treated by PTA/PTAS, 8 had good outcomes (mRS 0–2) and 11 had poor outcomes (mRS 3–6). There were no differences in the clinical or patient background except for the National Institutes of Health Stroke Scale (NIHSS) score between groups. The good outcome group had a lower NIHSS score than the poor outcome group (median: 9.5 vs 35, p <0.001). The Thrombolysis in Cerebral Ischemia (TICI) 2b-3 group had a slightly more favorable outcome than the TICI0-2a group (p = 0.10). There were no differences in outcome between PTA and PTAS groups (p = 0.65).

Conclusion: Reperfusion of the posterior circulation by PTA/PTAS may be necessary for a good outcome. Although acute stenting must be performed under careful observation, a stent can be placed when recurrence in the early phase is estimated with high probability.

Objective: While wide-neck aneurysms can be treated with several methods, we report the specific technique of intraaneurysmal neck plasty (IANP) with a super compliant double-lumen balloon microcatheter (Super-Masamune).

Methods: The Super-Masamune was inflated inside 18 aneurysms. Cases in which the tip of the Super-Masamune was located in the aneurysm were included. Embolization methods were the same as those used in the application of other balloons/stents. The use of the Super-Masamune for the performance of IANP followed two patterns: (1) the Super-Masamune was used not only as a balloon but also for coil insertion (simple IANP); (2) the Super-Masamune was used only as a balloon, and a microcatheter for coil insertion was separately introduced coaxially (coaxial IANP).

Results: The aneurysms were located in the anterior communicating artery (n = 6), middle cerebral artery (MCA; n = 4), anterior cerebral artery (n = 1), internal carotid artery (n = 5), basilar artery (n = 1), and vertebral artery (n = 1). Eight of the aneurysms were ruptured, while 10 were unruptured. Simple and coaxial IANP were both performed in seven cases. Embolization was not performed after inflating the Super-Masamune inside the aneurysm in four cases. Embolization grades following the procedure included eight neck remnants (NRs) and six body fillings (BFs). There was one complication of intraoperative rerupture; however, there was no rupture/rerupture in the follow-up period. Retreatment of the target aneurysm was performed in two cases. The embolization grade assessed in the follow-up period reached complete occlusion for one patient, NR for five, and BF for two patients.

Conclusion: IANP using the Super-Masamune is useful for the treatment of wide-neck aneurysms in which the introduction of a guidewire and/or microcatheter into the branching artery is difficult.

Objective: There are several methods to treat wide-neck aneurysms. We survey the cases that were treated using a super-compliant double-lumen balloon microcatheter (Super-Masamune) for preservation of the branching vessel originating proximal to the aneurysm, especially in the bulging neck plasty (BNP) technique.

Methods: We assessed 10 cases in which branching vessel preservation was performed using Super-Masamune. The cases were categorized into three groups: (1) ordinary neck plasty (ONP): balloon microcatheter was navigated to the branch that should be preserved; (2) BNP: another branch was preserved by inflating balloon bulging without cannulation; (3) protection during parent artery occlusion (PPO): the balloon microcatheter was navigated to the vessel to be occluded. The balloon preserves a branch originating near the aneurysm without cannulating to the branch.

Results: The aneurysm locations were as follows: internal carotid artery (ICA), three cases; anterior communicating artery (AcomA), one case; basilar artery (BA), three cases; and vertebral artery (VA), three cases. Four cases were ruptured aneurysms, while six cases were unruptured or ruptured in chronic stage. The ONP, BNP, and PPO groups contained two, five, and three cases, respectively. Embolization resulted in complete obliteration in six cases, neck remnant in two cases and body filling in two cases. No rupture/rerupture was noted in this series. One case showed an intraoperative rupture.

Conclusion: Super-Masamune is useful for neck plasty, especially BNP, in wide-neck aneurysms. Super-Masamune is also useful for parent artery occlusion when an important branch originates proximal to the aneurysm.

Objective: Hemangiopericytomas (HPCs) and solitary fibrous tumors (SFTs) have been categorized as the same disease entity, SFT/HPC, since 2016. SFT/HPC is one of the most highly vascularized brain tumors, distinct from meningioma. The angioarchitecture also differs between these tumors. Understanding these differences can help interventionalists perform presurgical embolization more safely and effectively.

Methods: Vascular structures were analyzed in eight patients with central nervous system (CNS) SFT/HPCs, all of whom received presurgical embolization. The type of embolic materials used and the complication rates were compared between the CNS SFT/HPC cases and 39 meningioma cases treated within the same period. Characteristic angiographic features of SFT/HPC were identified, and we present their interpretation and utilization to inform embolization strategies.

Results: Four angiographic features of SFT/HPCs were identified. 1) Persistence of tumor stain and 2) feeders from branches of the internal carotid artery or vertebral artery were observed in all cases, while 3) connecting feeders (highly dilated vessels that originate from branches of other feeder vessels and run along the surface of one tumor compartment to feed another compartment) were observed in five out of eight cases. 4) Finally, an intratumoral arteriovenous shunt was identified in one case. The frequency of liquid embolic material use was significantly higher in SFT/HPC cases than in meningioma cases. No complications were observed in SFT/HPC cases, and all tumors were effectively removed.

Conclusion: The most appropriate presurgical embolization strategies differ between SFT/HPCs and meningiomas depending on the tumor angioarchitecture. A thorough understanding of the vascular anatomy is necessary for safe and effective embolization of SFT/HPCs.

Objective: The effectiveness of mechanical thrombectomy (MT) for anterior circulation large vessel occlusion (LVO) is controversial in elderly patients. The aim of this study was to evaluate the efficacy of MT in octogenarians.

Methods: One hundred and sixty-five patients who underwent MT for anterior circulation LVO between May 2014 and August 2019 at our institution were evaluated. Patients were divided into two groups, the elderly group (≥80 years) and non-elderly group (<80 years), and we compared the effective recanalization rate (Thrombolysis in Cerebral Infarction 2b-3), good outcome rate (modified Rankin Scale 0–2 at 90 days), time from groin puncture to recanalization (P to R), symptomatic intracranial hemorrhage (sICH), and mortality rate between them retrospectively. Eligible patients for MT were judged using the Japanese stroke guidelines, and the selection criteria were more carefully applied to elderly patients.

Results: MT was performed on 48 elderly patients (29.1%) and 117 non-elderly patients (70.9%). On the other hand, 10 elderly patients (19.6%) and 5 non-elderly patients (5.4%) did not undergo MT even though they met the inclusion criteria. There were significantly fewer male patients and smokers in the elderly group, but other baseline and clinical characteristics were not significantly different between the groups. Effective recanalization (elderly 93.8% vs non-elderly 91.5%), good outcome (45.8% vs 60.7%), P to R (33.5 minutes vs 33.5 minutes), sICH (2.1% vs 4.3%), and mortality (8.3% vs 2.6%) were not significantly different between the two groups.

Conclusion: When recanalization was achieved by strict preoperative evaluation of clinical conditions and imaging, MT may be safe and effective even for octogenarians or older patients.

Objective: The safety and efficacy of thrombectomy for small-artery occlusions is still controversial. In April 2019, Tron Fx, a stent retriever with an expansion diameter of 2 mm, became reimbursed by health insurance in Japan. We report on cases of thrombectomy for small-artery occlusions performed using this device in seven patients.

Methods: The subjects were seven patients who underwent thrombectomy between July 2019 and June 2020 using Tron Fx with 2 mm in diameter. We analyzed clinical results including recanalization and complications.

Results: The mean age of the seven patients was 80.1 years, and the subjects included six men. The sites of occlusion were the middle cerebral artery M2 (n = 4), M4 (n = 1), anterior cerebral artery A2 (n = 1), and A3 (n = 1). One of the seven patients had an M2 occlusion that was formed during coil embolization for a ruptured cerebral aneurysm. In five cases, four cases were of primary occlusion and one case was of emboli into a new territory, treating with only Tron Fx 2 mm resulted in thrombolysis in cerebral infarction (TICI) 2b–3 in four cases. There was one case of grade 0, which was M4 occlusion. Finally, TICI 2b–3 were achieved in six of seven cases. No symptomatic intracranial hemorrhage occurred. Symptoms improved in five of six patients, excluding a vascular occlusion that occurred during surgery.

Conclusion: Tron Fx with 2 mm diameter can be used safely for small-artery occlusion. The introduction of Tron Fx with 2 mm diameter may contribute to expand indications for thrombectomy for small-artery occlusions.

Objective: We report a case of ruptured aneurysm at the anterior pontine segment of the anterior inferior cerebellar artery (AICA) which re-ruptured after stent placement and was treated by overlapping stenting.

Case Presentation: A 53-year-old woman presented with headache. CT demonstrated subarachnoid hemorrhage. DSA revealed no evident source of bleeding. On day 10, she complained of sudden headache and CT demonstrated re-bleeding. On repeated DSA, an aneurysm at the anterior pontine segment of the right AICA was found. An LVIS Jr. stent was deployed at the right AICA including the aneurysm. On postoperative day 23, the aneurysm ruptured again. Another LVIS Jr. stent was deployed at the same area. On day 56, she was discharged home without neurological deficit.

Conclusion: Intracranial aneurysms not indicated for coil embolization or parent artery occlusion are difficult to treat. Overlapping stenting may be a treatment option for such aneurysms.