Objective: Blood blister-like aneurysms (BBAs) of the internal carotid artery are highly challenging to treat due to their variable morphology and tendency for rupture and regrowth. Here, we report a single-institution experience of endovascular therapy (EVT) for BBA treatment.

Methods: We retrospectively reviewed patients with ruptured BBA from 2006 to 2019. All patients in whom BBA was treated with EVT were included. Patients’ aneurysmal characteristics, progression status, aneurysm occlusion on follow-up angiography, and modified Rankin Scale (mRS) score were recorded.

Results: A total of 11 patients (5 women and 6 men) with the mean age of 46 ± 10 years were included in this study. As initial treatment, 9 patients were treated with stent-assisted coiling (SAC). Immediate angiographic results showed that 2 cases were body filling, 4 were neck remnant, and 3 were complete obliteration. Perioperative ischemic complications were not observed. On postoperative day 1, 2 patients suffered from rerupture, and their prognoses were poor. Retreatments were performed in 5 patients. Parent artery occlusion (PAO) was performed in 6 patients including 2 initial treatments and 4 retreatments. Symptomatic infarction developed in 2 patients. In 3 patients, bypass in combination with PAO was performed. Clinical data revealed discharge mRS scores of 0–2 and 3–6 in 4 and 7 patients, respectively.

Conclusion: SAC is effective for the management of BBA. Careful follow-up and response are necessary after treatment with SAC.

Objective: Stretching or avulsion of a small perforating artery caused by mechanical traction contributes to intracranial hemorrhagic complications in mechanical thrombectomy, especially for medium and small-vessel occlusions. This study aimed to measure the pullout resistance during stent retriever (SR) traction and aspiration catheter (AC) traction with or without thrombi and characterize the mechanical properties of each device.

Methods: We placed the thrombectomy device in the area corresponding to the insular segment of the middle cerebral artery of a silicon carotid artery model. The thrombectomy device was automatically pulled out at a constant velocity using a horizontal motorized test stand, and pullout resistance was continuously measured 2000 times per second using a digital force gauge. Five types of SRs and two types of ACs with or without thrombus were evaluated. The data were divided into four groups for analysis: SR without clot, SR with clot, AC without clot, and AC with clot.

Results: The line graph was a jagged waveform during SR traction, and it was a gentle curve during AC traction. The maximum pullout resistance was higher in the SR with clot group than the other groups. The coefficient of variation was higher in the SR group than the AC group, with or without clot.

Conclusion: The pullout resistance during SR traction was more fluctuated than that during AC traction. In the presence of a thrombus, pullout resistance for SR was substantially increased, whereas AC resistance was less susceptible to thrombi. The differences in characteristics may reflect differences in the frequency of mechanical traction injury between the devices during clinical use.

Objective: Determining the course of occluded vessels in advance will increase the success rate and safety of mechanical thrombectomy (MT). Herein, we evaluate the usefulness of MR fusion images created via 3D T2-weighted sampling perfection with application-optimized contrasts using different flip angle evolutions (T2-SPACE) and 3D time-of-flight (TOF)-MRA for visualization of occluded vessels in patients with acute ischemic stroke (AIS) before MT.

Methods: We enrolled 26 patients with AIS caused by intracranial large vessel occlusion who presented at our hospital and underwent MRI with fusion images unaffected by motion artifacts in our study. All patients underwent T2-SPACE and TOF-MRA followed by MT. We created fusion images of the T2-SPACE and TOF-MRA by combining a translucent image of the occluded artery produced by the flow void effect in T2-SPACE with the same vessel in a TOF-MRA image. Fusion images were compared with post-recanalization angiography and post-recanalization MRA, respectively, and the degree of agreement in depiction of M1 runs and M2 branching beyond the occlusion on three levels was assessed. Imaging evaluations were performed independently by two endovascular specialists.

Results: The interobserver agreement of the MRI findings about the concordance of the occluded vessel’s run was excellent (kappa was 0.87 [confidence interval: 0.61–1.12]). In all, 21 patients (80.8%) had excellent imaging, four (15.4%) had fair imaging, and one (3.8%) had a divided opinion of the rating between excellent and fair imaging. No cases were judged to be poorly drawn. Even if there was a localized signal loss, its distal portion could be delineated, so it did not affect the estimation of the entire vessel run, and we found that the anatomical structures of the occluded vessels were distinctly visible in the fusion images.

Conclusion: We demonstrated that MR fusion images derived using T2-SPACE and MRA methodologies could determine the courses of occluded vessels prior to MT performed for AIS. Fusion MR imaging may have potential as a preoperative test for ensuring effective and safe MT procedures.

Objective: To facilitate understanding for the safe use of the Wingspan stent, a comprehensive literature analysis was conducted, and incidence rates of 30-day stroke or death before and after the Stenting versus Aggressive Medical Management for Preventing Recurrent Stroke in Intracranial Stenosis (SAMMPRIS) trial were compared. We also investigated the associations between 30-day stroke or death rate and four lesion vessels, the internal carotid artery (ICA), middle cerebral artery (MCA), basilar artery (BA), and vertebral artery (VA).

Methods: We searched MEDLINE, Embase, Web of Science, and Cochrane Library databases. The incidence rates of 30-day stroke or death in pre- and post-SAMMPRIS were compared using forest plots and funnel plots.

Results: Thirty studies (15 before and 15 after the SAMMPRIS) were identified, comprising 2071 patients. Post-SAMMPRIS studies showed lower incidence rates of 30-day stroke or death compared to the pre-SAMMPRIS studies (8.5% vs. 5.6%, p = 0.014). The odds ratio of 30-day stroke or death of the post-SAMMPRIS group compared to that of the pre-SAMMPRIS group was 0.64 (95% confidence interval: 0.45–0.92, p = 0.014).

The average 30-day stroke or death rates of overall, pre-, and post-SAMMPIS studies were 1.1%, 1.1%, and 1.1% for ICA; 6.2%, 8.8%, and 5.3% for MCA; 0.9%, 6.0%, and 2.7% for VA; and 13.5%, 15.1%, and 12.5% for BA, respectively. The post-SAMMPRIS study group showed significantly lower event rates for the treatment of MCA and VA than the pre-SAMMPRIS group did (p = 0.003 and p = 0.006, respectively). The incidence rates of ischemic and hemorrhagic stroke were 3.5% and 2.0%, respectively.

Conclusion: This systematic surveillance study indicated that the modification of the indications for use based on the results of the SAMMPRIS trial for the Wingspan stent was effective in reducing 30-day stroke or death.

Objective: Injury to the inferior epigastric artery (IEA) caused by femoral puncture may lead to retroperitoneal hematoma. We report on two cases of IEA injury due to femoral venipuncture for neuroendovascular intervention that resulted in hemorrhagic shock and required transcatheter arterial embolization.

Case Presentations: A 67-year-old woman and a 71-year-old man receiving dual antiplatelet therapy sustained injury to a branch of the IEA in the process of right femoral venipuncture for neuroendovascular intervention. In both cases, stent placement in the intracranial artery was accomplished as intended with systemic heparinization throughout the procedure; however, the patients became hypotensive during the procedure, and contrast-enhanced CT scans taken after the stenting revealed extravasation of contrast from the IEA and retroperitoneal hematoma. Transcatheter arterial embolization of the bleeding branch of the IEA was performed with the left femoral approach, and subsequent angiography confirmed the disappearance of the extravasation of contrast.

Conclusion: Femoral venipuncture for neuroendovascular intervention in patients receiving antithrombotic agents may cause IEA injury requiring transcatheter arterial embolization. The risk of IEA injury may be reduced by using the femoral head as a reference, performing ultrasound-guided puncture, and confirming the course of the IEA by femoral angiography before venipuncture.

Objective: To report a case of an acutely ruptured vertebral artery dissecting aneurysm (VADA) with a hypoplastic contralateral vertebral artery (VA) successfully treated with internal trapping following the estimation of the collateral flow from anterior circulation.

Case Presentation: A 46-year-old woman was diagnosed with subarachnoid hemorrhage and acute hydrocephalus. Ventriculostomy was performed under general anesthesia. CTA revealed a left VADA distal to the origin of the left posterior inferior cerebellar artery (PICA). The right VA was hypoplastic, and the right posterior communicating artery (Pcom) was fetal type. We performed balloon test occlusion (BTO) of the VA proximal to the origin of the left PICA and estimated sufficient collateral blood flow via the right Pcom and basilar artery (BA) to the anterior spinal artery (ASA) and the left PICA. Internal trapping of the left VADA was then performed. The angiograms after internal trapping revealed collateral flow from the right Pcom to the BA, and the hypoplastic right VA perfused the proximal BA and ASA. She recovered without any neurological deficits following antiplatelet therapy and vasospasm treatment. She was followed up for 6 years without any neurological events occurring.

Conclusion: When BTO indicates sufficient collateral flow, internal trapping could be a useful treatment for acutely ruptured VADAs on the dominant side, given a complete understanding of the angioarchitecture and the risk of vasospasm due to subarachnoid hemorrhage.

Objective: The Mo.Ma Ultra is an embolic protection device used in carotid artery stenting (CAS). In cases of left internal carotid artery stenosis (ICS) in which the common carotid artery (CCA) branches off the aortic arch at a steep angle, insertion of the Mo.Ma Ultra into the CCA is sometimes difficult. We introduce a “buddy catheter technique” that helps guide the Mo.Ma Ultra into the CCA, with an additional 4 Fr catheter into the external carotid artery.

Case Presentation: An 84-year-old man with left ICS whose CCA also branched off the aortic arch at a steep angle also underwent CAS. The “buddy catheter technique” was used, and the Mo.Ma Ultra was inserted smoothly. The buddy catheter technique displaces the left CCA upward. Displacement straightens the vessels anatomically, and the ledge effect can be prevented by aligning the course of the vessels with the wire. Nevertheless, this technique requires bilateral femoral puncture, and so, complications can occur.

Conclusion: The buddy catheter technique may be considered in cases in which the left CCA branches off the aortic arch at a steep angle.