Objective: The mechanism of transient cortical blindness after endovascular treatment—a rare phenomenon—has not been elucidated; however, it is assumed to be related to contrast medium leakage (CML). We investigated the relationship between postoperative CML and cortical blindness in patients who underwent endovascular treatment for vascular lesions of posterior circulation.

Methods: This retrospective cohort study included 28 patients who underwent endovascular treatment for posterior circulation aneurysms at our hospital between January 2014 and December 2018. Cerebral CT was performed immediately after endovascular treatment and 24 h later. CT images were retrospectively evaluated with special interest in the presence and distribution of leakage of the contrast medium (CM). Patients were classified into the following three groups based on CT findings: Group A, no CML (11 patients); Group B, unilateral CML (5 patients); and Group C, bilateral CML (9 patients).

Results: The posterior circulation aneurysms were located in the basilar artery in 13 (52.0%) cases, in the posterior cerebral artery in 1 (4.0%) case, and in the vertebral artery in 11 (44.0%) cases. There was no difference regarding the adjunctive technique used for endovascular treatment between the groups. Patients in Group C used a significantly larger amount of CM than those in the other two groups. A longer operation time was associated with a larger amount of CM used during treatment. VerifyNow assay revealed that the P2Y12 reaction unit was significantly lower in Groups B and C. Cortical blindness was transiently observed in 2 of 9 patients (22.2%) in Group C, both of which showed CML surrounding the bilateral parieto-occipital sulcus.

Conclusion: Both patients with cortical blindness showed bilateral CML, both of which showed CML surrounding the bilateral parieto-occipital sulcus. The CM-induced blood–brain barrier disruption may be the cause of cortical blindness.

Objective: The development of large-bore aspiration catheters (ACs) has advanced the treatment of mechanical thrombectomy (MT) and their use requires larger guiding catheters (GCs). However, due to the small vessel diameter of the vertebral artery (VA), it can be difficult to cannulate large-bore GC to the VA. This study aims to determine the percentage of VAs that are amenable to GC placement based on the use of a large-bore AC and to clarify the diameters of VAs in the general population using neck MRA.

Methods: Left and right VA diameters were measured in 1394 consecutive adult patients who underwent neck MRA at our hospital between April 2020 and June 2021. Sex and left/right differences in the VA diameters, as well as the conformity ratios of GCs (6, 7, and 8 French) to right and left VAs, were examined.

Results: The patients ranged in age from 18 to 98 years (mean 70.8 ± 13.5 years), with 770 (55.2%) males. The left and right VA mean diameters were 2.82 ± 0.75 mm (range 0–5.1 mm) and 2.65 ± 0.75 mm (range 0–5.3 mm), respectively. The conformity ratios of 6, 7, and 8 French GC to left and right VAs were 85.3% and 79.9%, 74.9% and 68.4%, and 60.9% and 53.7%, respectively.

Conclusion: When performing MT for the posterior circulation system, a large-bore AC of 0.060 inches or larger is usually required, and GC placement of 7-French or larger is necessary. The results of this study showed that 7-French GC placement is achievable in approximately 70% of these cases.

Objective: Time to recanalization is directly linked to cerebral infarction prognosis. However, patients transferred from another hospital take longer to arrive than those transported directly. To minimize time to recanalization, the emergency room (ER) skip strategy for hospital transfers was executed and reviewed.

Methods: From April 2019, patients transferred from another hospital for mechanical thrombectomy were carried into the angio-suite using emergency service stretchers. Results for these patients (ER skip group) were compared with those for patients transported directly to our hospital (Direct group).

Results: Among 108 cases in 32 months, 99 patients (91.7%) had major cerebral artery occlusion and underwent endovascular treatment. No differences in age, baseline National Institutes of Health Stroke Scale score, effective recanalization rate, or proportion of posterior circulation cases were seen between groups. The ER skip group (26 patients) showed significantly longer median time from onset to arrival (240 vs. 120 min; p = 0.0001) and significantly shorter median time from arrival to groin puncture (11 vs. 69 min; p = 0.0000). No significant differences were evident in time from groin puncture to recanalization (39 vs. 45 min), time from onset to recanalization (298 vs. 244 min), or rate of modified Rankin Scale score 0–2 after 90 days (42.3% vs. 32.9%). Median time from alarm to recanalization (266 vs. 176 min; p = 0.0001) was significantly longer in the ER skip group. Door-to-puncture (DTP) time for the Direct group gradually fell as the number of cases increased, reaching 40 min by the end of study period. In contrast, DTP time for the ER skip group remained extremely short and did not change further. The proportion of patients who underwent both CT and MRI before endovascular treatment was significantly lower in the Direct group (30.1%) than in the ER skip group (57.7%). In the ER skip group, median length of stay in the primary hospital was 119 min, and the median duration of interhospital transfer was 16 min.

Conclusion: The ER skip strategy for patients transferred with large vessel occlusion achieved favorable outcomes comparable to that for direct transport cases. Direct transport to a thrombectomy-capable stroke center remains ideal, however, because the time to intervention is improving for direct transport cases each year.

Objective: Treatment of large posterior cerebral artery (PCA) aneurysm involving the P1–P2 segment is difficult by both neurosurgery and endovascular treatment. Balloon occlusion test (BOT) to identify precise peripheral collateral flow is difficult prior to parent artery occlusion (PAO). Besides, PAO at the aneurysm at this location can cause peripheral cortical infarction of the occipital and temporal lobes and/or perforator infarction involving the midbrain and thalamus perfused by the perforating artery arising from the P1–P2 segment. However, detection of the perforator during PAO is difficult.

Case Presentation: The patient was a 49-year-old woman. At the age of 43 years, a right large PCA aneurysm was discovered in the right P1–P2 segment. A simple technique coiling was performed. As recurrence was identified 1 year later, embolization was performed using a same procedure. Since further recurrences were later found, a third round of treatment was planned. Somatosensory-evoked potential (SEP) was recorded as intraoperative electrophysiological monitoring. Tortuosity of the right PCA was observed at the aneurysm neck and the distal right PCA could not be secured. We could neither perform stent-assisted coil embolization nor BOT in the right PCA. Hence, we inflated the balloon in the basilar artery and checked the collateral circulation routes retrograde into the right PCA from the right middle cerebral artery via a leptomeningeal anastomosis. PAO was performed on the right P1–P2 segment at the aneurysm neck. The signal of the SEP was not decreased, and the aneurysm was not visualized. Another coil was added to strengthen the PAO to the right P1 segment, which decreased the SEP amplitude in the extremities by 3 minutes after. As the last coil was thought to be occluding the perforator branching from the right P1 segment, it was removed without detaching. The SEP amplitude began to improve and recovered by 9 minutes after. There was no postoperative deficit. No recurrence of aneurysm was observed on MRA 9 months postoperatively.

Conclusion: During PAO at the P1 segment of large PCA aneurysm involving the P1–P2 segment, SEP may be helpful to prevent perforator infarction, even if perforating artery originating from the proximal portion of the aneurysm was not detected by angiography.

Objective: We report a case of huge scrotal hematoma during emergency mechanical thrombectomy.

Case Presentation: An 85-year-old man presented with sudden aphasia and right-sided hemiplegia. He was diagnosed with cerebral infarction due to left M1 occlusion and underwent an emergency mechanical thrombectomy. The treatment was completed with full recanalization, but when replacing the long sheath in the right femoral artery with a short sheath, the patient flexed his leg. The sheath could not be replaced, resulting in a massive scrotal hematoma. Shortly after, the patient went into cardiopulmonary arrest but recovered spontaneous circulation after cardiopulmonary resuscitation. The puncture site was treated hemostatically with manual compression, and the scrotal hematoma was not enlarged. He was transferred to another hospital with a modified Rankin Scale score of 5.

Conclusion: Scrotal hematoma is a rare but potentially fatal puncture site complication that should be considered during neuro-endovascular treatment.

Objective: We describe 3 cases with folding deformation of a PRECISE (Cordis, Miami, FL, USA) stent in carotid artery stenting (CAS).

Case Presentations: The 3 cases with cervical carotid stenosis consisted of 3 males around 80 years old and included 2 symptomatic lesions. During CAS, distal embolic protection was established using a Mo.Ma (Medtronic, Minneapolis, MN, USA) along with a filter device in 2 cases and an Optimo (Tokai Medical Products, Aichi, Japan) along with a filter device in 1 case. For the filter device, either FilterWire EZ (Boston Scientific, Natick, MA, USA) or Spider FX (Covidien, Irvine, CA, USA) was employed. In all cases, a PRECISE stent was deployed after pre-dilation performed using a percutaneous transluminal angioplasty (PTA) balloon with the diameter of 2.5 to 3 mm. Post-dilation was performed after the stent deployment using a PTA balloon whose diameter was about 80% of that of the normal distal internal carotid artery. In all cases, cone-beam CT taken after the deployment of a stent showed folding deformation of the stent. In 2 cases, heavily calcified plaque hampered self-expansion of the stent, which resulted in the stent deformation. On the other hand, in the remaining 1 case, a distal shaft of the Mo.Ma caused the stent deformation, which was likely accelerated by head rotation and cervical compression that was performed to resolve difficulties for a filter retrieval device to pass through the stent, and post-dilation after the stenting.

Conclusion: Heavily calcified plaque and a distal shaft of a Mo.Ma would result in stent deformation.