Objective: To report the outcomes of thrombectomy for arterial occlusion involving the major arteries of the cerebral anterior circulation when an aspiration catheter (AC) was used in all cases, with the retrieval technique chosen during the procedure.

Methods: Of the 126 patients who underwent endovascular thrombectomy during the 2-year period of 2018–2019, the study subjects were 102 patients with arterial occlusion involving the major arteries of the cerebral anterior circulation. Patients were divided into two groups depending on when the procedure was performed. In the earlier group (January 2018–March 2019), treatment was performed using only a stent retriever (SR), whereas an AC was used for all cases in the later group (April–December 2019). Outcomes between groups were retrospectively compared. In the later group, the treatment strategy was to use the SR in combination with the AC (combined technique) for retrieval if the microcatheter reached the distal side of the occlusion site without difficulty. If the microcatheter did not easily reach the distal side, we did not stick to penetrating the occlusion site, and contact aspiration was performed.

Results: Thrombolysis in cerebral infarction (TICI) grade 2b–3 was achieved in 85% of patients in the earlier group and 95% in the later group. TICI grade 3 was achieved in 52% of the earlier group and 54% of the later group, showing no significant difference. TICI grade 2b–3 was achieved at first pass in 46% of patients in the earlier group, significantly lower than the 71% in the later group (P = 0.013). The mean number of passes decreased significantly from 1.84 in the earlier group to 1.32 in the later group (P = 0.002).

Conclusion: Using an AC from the start, and using a combined technique when the microcatheter reached the distal side of the occlusion site, the frequency of first-pass TICI grade 2b-3 increased, and the mean number of passes decreased in comparison with the SR-alone group.

Objective: Mechanical thrombectomy enables histopathological examination of clots in patients who have suffered acute ischemic strokes. Many studies have described about the relationship between the histopathological compositions of retrieved thrombi and imaging findings, clinical outcomes, and stroke etiology without consensus. In this study, we examined the histological composition of thrombi according to their retrieval site and methods.

Methods: We divided retrieved clots into three parts (those retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter) and then histopathologically analyzed their compositions by measuring the area occupied by red blood cells (RBCs), fibrin/platelets (F/Ps), and white blood cells (WBCs).

Results: Each specimen showed various composition even within the same patient. For example, the area occupied by RBCs was 20.9% ± 12.1%, 30.5% ± 13.5%, and 41.3% ± 16.1% in the clot retrieved from the proximal and distal parts of the stent retriever, and those aspirated through the guiding catheter, respectively.

Conclusion: Histopathological clot composition may vary even within the patient. Further research is needed to investigate more objective methods of histopathological analysis and their clinical significance.

Objective: Coil compaction after aneurysm embolization is one of the major issues associated with aneurysm recurrence. On the presumption that pulsatile stress to the aneurysm is responsible for coil compaction, we developed an experimental model in vitro to visualize the mechanical stresses exerted by blood pressure and pulse and their relation to coil compaction.

Methods: A closed-type non-circulation system was developed by installing a syringe that generated pressure at one end of a tube, along with a spherical aneurysm made of silicone and a pressure sensor in the bifurcated end. We installed a fixed-pressure model under a steady pressure of 300 mmHg while the pressure-fluctuation model simulated the pressure variations using a plunger (in a syringe) by using a motor that applied pulsatile stress in the range of 50 mmHg for a 10-ms cycle. We devised four types of aneurysms with different depths and the same coil length. After coil packing, the aneurysms were observed for 3 days (the observation period in the pressure-fluctuation model corresponded to approximately 300 days in real time). The distance from the datum point to the observable coil loops was determined as the initial position, and the temporal change in the distance from that position was measured.

Results: In the fixed-pressure model, the average distance of coil movement was very small (less than ±0.1 mm). In the pressure-fluctuation model, the movement of coils was observed to be significant for the two longest depths (0.11 and 0.14 mm). The maximal dynamic change in coil movement was observed on the second day. The range of movement was observed to decrease thereafter.

Conclusion: Our experimental study enabled the observation of coil movement within a short duration. It examined coil compaction by applying pulsed pressure to the coils at high speeds. Consequently, a shift of the coil loops inside the incompletely occluded aneurysms was detected on applying a pulsed pressure.

Objective: Endovascular coil embolization for anterior communicating artery (ACoA) and anterior cerebral artery (ACA) aneurysms is associated with high total and near-total occlusion rates, but the complication rate is high. The development of newer endovascular technologies may improve the clinical outcomes. This study investigated the status of endovascular treatment of ACoA and ACA aneurysms by comparing our results with past reports.

Methods: Between January 2006 and December 2018, we investigated 50 patients who were followed for 12 months or longer to clarify the outcomes of coil embolization. The outcomes of embolization were evaluated using time-of-flight MRA. The safety was evaluated based on procedure-related complications that affected clinical outcomes.

Results: Initial assessments demonstrated complete obliteration in 84% (42 of 50 patients) and a residual neck in 14% (7 of 50 patients). Procedure-related complications developed in 12% (6 of 50 patients). The procedure-related morbidity rate was 2% (1 of 50 patients) and there was no procedure-related death. Recanalization was noted in 14% (7 of 50 patients, median follow-up period, 57 months). The recanalized aneurysms were significantly smaller than the stable aneurysms in maximum size (4.3 mm vs. 5.8 mm; p = 0.017) and height (3.7 mm vs. 4.3 mm; p = 0.035).

Conclusion: We demonstrated the safety and effectiveness of endovascular coil embolization for ACoA and ACA aneurysms. The small size of aneurysms may be related to recanalization.

Objective: We report a rare case of intraosseous arteriovenous fistula (AVF) in the petrous bone occluded by transvenous coil embolization, complicated by transient hearing loss postoperatively.

Case Presentation: A 55-year-old female patient underwent medical examination for vertigo and headache. CT showed an osteolytic lesion in the right petrous bone. CTA and DSA revealed an AVF that had caused bone erosion. We performed transvenous coil embolization to obtain complete occlusion of the fistula. Vertigo disappeared soon after the procedure, but hearing loss in the right side worsened to near deafness by that night. We started steroid pulse therapy and heparinization. The hearing gradually recovered to the preoperative level in 10 days.

Conclusion: It is important to pay attention to possible hearing loss in cases of transvenous coil embolization for intraosseous AVF in the petrous bone.

Objective: Accidental puncture of the vertebral artery (VA) by central venous catheters and other devices has been reported as a rare complication. We performed endovascular therapy in the acute phase in a patient in whom a large-caliber sheath was misinserted into the VA.

Case Presentation: A 68-year-old woman scheduled for open heart surgery had an 8-Fr. sheath inserted through the right internal jugular vein (IJV). This sheath penetrated the IJV and was misplaced in the V1 segment of the right VA. Endovascular therapy was performed. First, a 9-Fr. balloon-guiding catheter (BGC) was inserted and a 0.035-inch guidewire was pulled through it and the 8-Fr. sheath misinserted into the right VA. A 6-Fr. guiding catheter was inserted into the left VA and the microcatheter reached distal of where the sheath was inserted via the basilarunion. Then, the same area was embolized with coils to block retrograde blood flow. The BGC was then guided to the right VA origin using a pull-through wire while the 8-Fr. sheath was carefully withdrawn. The sheath was pulled back until just before exiting the VA and additional coils were placed via a microcatheter inserted into the BGC to occlude the right VA. Postoperatively, the patient had no neurological findings.

Conclusion: We reported a rare case of iatrogenic VA injury. Attention to hemorrhage and intracranial blood flow resulted in a favorable outcome.

Objective: Posterior condylar canal dural arteriovenous fistula (PCC DAVF) is extremely rare, with only four previously reported cases in the English literature. Cases may present tinnitus and radiculopathy. In cases where the drainer is around the brainstem, subarachnoid and intraventricular hemorrhages (IVHs) may occur. We describe the clinical presentation, angiographic imaging, and endovascular treatment strategy of a PCC DAVF.

Case Presentation: A 30-year-old woman presented to our hospital with tinnitus and stiffness of the shoulder. Neuroimaging studies showed DAVF with fistulous points around right PCC consisted of a high-flow shunt, fed mainly by the occipital artery, and drained to the suboccipital cavernous sinus (SCS) and internal jugular vein. The lesion was treated with a combination of transvenous coil embolization and transarterial Onyx injection. The patient recovered immediately after intervention and had no neurological deficits in the follow-up visit.

Conclusion: In this case, endovascular treatment was performed safely without recurrence so far. A strategy combining transvenous coil embolization and transarterial Onyx injection may be an effective treatment for PCC DAVF with high-flow shunt. Further case accumulation is desired.

Objective: Carotid artery stenting (CAS) using the stent-in-stent technique was reported to prevent intraprocedural plaque protrusion (PP) in patients with carotid artery stenosis with unstable plaque. We report a case of intraoperative PP after CAS despite the use of stent-in-stent technique.

Case Presentation: A 63-year-old man presented with rapid progression of right carotid artery stenosis with unstable plaque during follow-up and was admitted to undergo CAS. Under local anesthesia with Mo.Ma Ultra and FilterWire EZ protection, CAS was performed using the stent-in-stent technique. The first 8 mm × 29 mm Carotid Wallstent (CWS) was placed. The second CWS (6 mm × 22 mm) was placed in a stent-in-stent manner to match the stenotic lesion, and conservative postdilation was performed. Then the third CWS (6 mm × 22 mm) was added due to the presence of PP on intravascular ultrasonography (IVUS). No postoperative neurological abnormalities were found, and no new high-signal areas were observed on diffusion-weighted MRI the day after surgery. The patient was discharged without postoperative complications. No stroke and restenosis were observed at 3 months after CAS.

Conclusion: PP can occur even with stent-in-stent technique, suggesting the importance of diagnosis by IVUS.

Objective: Stent fracture is a risk factor for stroke. It has not been fully elucidated whether stent-in-stent procedures can effectively treat stent fractures.

Case Presentation: An 80-year-old man underwent carotid artery stenting (CAS) with an open-cell stent to treat asymptomatic right internal carotid artery (ICA) stenosis. Type III stent fracture occurred during CAS. Six months later, in-stent stenosis progressed on DSA. Repeat CAS with a closed-cell stent was performed. CT showed expansion of the narrowed lumen. The patient remained stroke-free and carotid artery restenosis did not occur for 3 years postoperatively.

Conclusion: Repeat CAS with a closed-cell stent is a viable treatment option for stent fracture.

Objective: We treated a case of scalp arteriovenous malformation (sAVM) by transvenous embolization using Onyx.

Case Presentation: We describe the case of a 17-year-old woman with a pulsatile mass at the right temporal area. DSA identified sAVM with the venous pouch between the right occipital artery (OA) and the right two occipital veins (OVs), which was also fed by multiple branches of the right posterior auricular artery (PAA) and superficial temporal artery (STA). The shunts were completely occluded by the reverse pressure cooker technique (RPCT), which involves navigating the balloon catheters just distal to the shunt point in the OVs approaching from the right external jugular vein (EJV) and injecting Onyx to each feeder retrogradely with balloons inflated.

Conclusion: This technique may be useful for treating sAVM with venous angioarchitecture enabling a transvenous approach.