Objective: Acute ischemic stroke due to large vessel occlusion (LVO) in hospitalized patients is relatively rare but important condition. However, unlike community-onset cases, there are only few time-saving protocols for in-hospital LVO. This study aimed to evaluate the time-saving effects of rapid response system (RRS) for the management of in-hospital LVO.

Methods: We retrospectively evaluated consecutive in-hospital LVO patients who underwent mechanical thrombectomy (MT) between April 2015 and January 2020. In November 2017, we added “acute hemiparesis, eye deviation, and convulsive seizures” to the activation criteria for RRS. In this protocol, the patient is immediately transported from the ward to the emergency room (ER) by Medical Emergency Team (MET). The stroke team can then start assessment in the same manner as for community-onset cases. The time metrics between those with and without RRS intervention were compared. The primary outcome was time from detection to the first assessment by stroke team and to initial CT. To investigate the validity of the revised criteria, we also analyzed all RRS-activated cases.

Results: In total, 26 patients (RRS group, 11 patients; non-RRS group, 15 patients) were included. The median time from detection to stroke team assessment (10.0 [interquartile range: IQR, 8–15] minutes vs 65.5 [18–89] minutes) and to CT (22.0 [16–31] minutes vs. 46.5 [35–93] minutes) were significantly shorter in the RRS group. RRS was activated in 34 patients (mean, 1.3/month) according to the added criteria, of whom 20 (58.8%) had cerebral infarction and 9 underwent MT. About two-thirds of the other patients developed neurological emergencies (e.g., epileptic seizure, syncope, or hypoglycemia) that required acute care.

Conclusion: RRS has the potential to shorten response time efficiently in the management of in-hospital LVO. Prompt transportation of the patient to the ER by MET enables faster intervention by the stroke team.

Objective: The balloon-assisted technique is one of the methods used for cerebral aneurysm embolization. There are several applications of assisting balloons such as remodeling the neck of cerebral aneurysms, protecting blood vessel branches, and stabilizing the microcatheter. In this study, we measured the pressure inside inflated assisting balloons to assess safety or procedure.

Methods: A T-junction silicone model was used. The pressure inside the balloon inflated to the set herniation levels in the T-junction model was measured using a fiber pressure sensor. We compared the pressure and difference between each assisting balloon.

Results: The pressure required for inflating the balloon to the set herniation level in the T-junction model varied depending on the type of assisting balloon. The results suggest that differences in pressure among inflated balloons are likely attributable to differences in the materials used in the lumens of the balloons.

Conclusion: The pressure inside various inflated assisting balloons was measured for comparison and differences were found. This experiment contributes to the safety of the balloon-assisted technique.

Objective: The most important function required for the stroke center is prompt treatment for acute stroke. We report the initial results of stroke care under the new medical care system of stroke center in a new hospital that merges three hospitals with different management bases to verify the effect of stroke center on mechanical thrombectomy.

Methods: We investigated changes in the number of inpatients and surgical treatments compared with the past 3 years (Stages I, II, and III) with stage IV one year after the new hospital was opened, and examined the effect of establishing a stroke center on mechanical thrombectomy for acute main cerebral artery occlusion.

Results: From stage I to stage IV, the number of hospitalized patients increased from 396, 485, 482 to 630, respectively, and the proportion of patients with cerebrovascular disease increased from 57.6%, 55.7%, 60.4% to 68.3%, respectively. Total surgical treatment increased from 137, 195, 224 to 297, respectively, especially endovascular therapy increased markedly from 22, 36, 68 to 118, respectively. The main treatment contents of endovascular treatment in stage IV were ruptured cerebral aneurysm embolization 22 cases, unruptured cerebral aneurysm embolization 13 cases, carotid artery stenting 23 cases, other intracranial or extracranial artery angioplasty/stenting 9 cases, and mechanical thrombectomy 34 cases. In particular, mechanical thrombectomy was significantly increased to 34 in stage IV, compared to 4 in stage I, 4 in stage II, and 17 in stage III (degree of contribution [DC] 25.0%, contribution ratio [CR] 34.0%).

Conclusion: With the establishment of the stroke center, the number of cases of acute cerebral infarction within the adaptation time who received mechanical thrombectomy remarkably increased. It is considered that the effect and validity of function aggregation by establishing stroke center are shown.

Objective: A traumatic vertebral artery (VA) injury may result in serious cerebral infarction in the vertebrobasilar area. However, the approach to its diagnosis and the optimal treatment have not yet been established. We present a patient with traumatic occlusion of a unilateral VA due to the multiple cervical spine fractures who required decompression and fixation, in whom the injured VA was coil embolized distal to the occlusion prior to the cervical spine surgery.

Case Presentation: A 47-year-old woman was injured in a car accident and, presented with C6-C7 superior articular process fractures and C2-C3 ossification of the posterior longitudinal ligament (OPLL) with sensory hypoesthesia and motor palsy of the left upper limb. MRA showed left VA occlusion and patent contralateral VA. DSA showed left VA occlusion from the origin to C5/6 and its antegrade flow by collateral orthodromic circulation from the muscular branches. To prevent vertebrobasilar infarction due to migration of the thrombus from the occluded VA which was recanalized by surgical fixation, distal coil embolization of the injured VA by navigating a microcatheter through the contralateral VA across the vertebrobasilar junction was performed. Neither ischemic events nor new neurologic symptoms occurred during follow-up.

Conclusion: Preoperative coil embolization to a traumatic VA occlusion can be one of the therapeutic choices to prevent thromboembolic stroke after cervical spine surgery. When the proximal segment of the VA was injured and VA occluded from origin, this treatment strategy is feasible, safe, and effective.

Objective: A case of posterior cerebral artery (P1 segment) occlusion with consciousness disturbance and Weber’s syndrome treated by mechanical thrombectomy is reported.

Case Presentation: The patient was a 69-year-old man with consciousness disturbance, left hemiparesis, and anisocoria. MRI revealed acute cerebral infarction in the midbrain and right thalamus. Angiography demonstrated that the right P1 segment was occluded and mechanical thrombectomy was performed. The right P1 segment and its perforator artery, the artery of Percheron (AOP), were both recanalized after the treatment, and the symptoms of perforator occlusion significantly improved.

Conclusion: Mechanical thrombectomy for P1 segment occlusion may be effective for improving the symptoms caused by occlusion of its perforator, the AOP.

Objective: Mechanical thrombectomy is performed on ischemic stroke patients with acute major cerebral artery occlusion within 24 hours of symptom onset. We report a case of delayed mechanical thrombectomy for acute left internal carotid artery occlusion.

Case Presentation: A 76-year-old woman suddenly presented with dysarthria and right hemiparesis was admitted to her previous hospital. She was treated by conservative therapy. The next day, she was transferred to our hospital 26 hours after onset with a diagnosis of ischemic stroke due to left carotid artery acute occlusion. Contrast CT revealed left carotid artery occlusion. Arterial fibrillation was detected. Mechanical thrombectomy through the right brachial artery was immediately performed. Complete recanalization was achieved without hemorrhagic complication. Her postoperative course was uneventful.

Conclusion: In this case, delayed mechanical thrombectomy for acute major cerebral artery occlusion was safely performed 24 hours after symptom onset.

Objective: We present a preoperative simulation of cerebral aneurysm coil embolization using a hollow model of cerebral blood vessels created by a stereolithography (SLA) 3D printer.

Case Presentation: The patient was a 66-year-old woman. During follow-up, coil embolization was planned for an expanding paraclinoid aneurysm. A hollow cerebral vascular model was created preoperatively using an SLA 3D printer. The catheter was malleable and inserted into the hollow model, which enabled the surgeons to confirm its movement, stability, and ease of insertion. In the surgical procedure, the catheter was easily inserted into the aneurysm without reshaping. The procedure was completed without stability problems.

Conclusion: The use of a hollow model of cerebral blood vessels was useful as a preoperative simulation and improved the safety of the procedure.

Objective: Although Onyx has made effective embolization possible in the endovascular treatment of arteriovenous malformation (AVM), its infusion requires a high level of skill and experience. The purpose of this study is to create a simulation model that will help to solve this technical issue.

Model Presentation: Using data of 3D DSA images of a clinical case, an acrylonitrile–butadiene–styrene (ABS) resin model of the AVM was created with a 3D printer. Then, a hollow elastic model was created by applying silicone and eluting the ABS resin, which was finally connected to the human vascular model. Simulation of angiography and Onyx embolization using the model showed similar angiographic features and flow dynamics of contrast media and Onyx. During Onyx embolization, the plug and push technique could be performed as in a clinical case.

Conclusion: 3D AVM model created with 3D printer enabled us to stimulate Onyx embolization of AVM.

Objective: We report the effectiveness of retrograde angiography via the contralateral carotid angiography using a dual puncture technique in mechanical thrombectomy (MT) for non-T occlusion in patients with acute internal carotid artery (ICA) occlusion not involving the ICA terminus.

Case Presentation: In the dual puncture technique, arterial puncture is performed at two sites: a balloon guiding catheter (BGC) is navigated to the ICA on the affected side and another catheter is navigated to the unaffected side. Thrombus retrieval is performed by manual aspiration through the BGC and MT using a stent retriever and/or aspiration device. Reperfusion is confirmed by retrograde angiography via the carotid artery on the unaffected side, with manual aspiration through the BGC on the affected side. Throughout the procedure, the BGC blocks the blood flow in the ICA on the affected side until reperfusion is confirmed. No distal embolization was occurred in our three patients treated using this technique.

Conclusion: Application of the dual puncture technique on MT is recommended for non-T occlusion to prevent distal embolization.

Objective: We report the utility of microcatheter reshaping by referring to fusion images with 3D-DSA and microcatheter 3D images made using non-subtraction and non-contrast (non-SC) rotational images.

Case Presentations: Case 1: The patient was a 74-year-old man who had an internal carotid-anterior choroidal artery bifurcation aneurysm with a tortuous proximal parent artery. The initial attempt to introduce the microcatheter into the aneurysm was unsuccessful. During this unsuccessful microcatheter introduction, we created fusion images with 3D-DSA and microcatheter 3D images by acquiring positional information of the microcatheter using the non-SC method. By reshaping the microcatheter with reference to the fusion images, the direction of the distal end of the microcatheter was reshaped to be in accordance with the long axis of the aneurysm, a shape more suitable for coiling. Case 2: The patient was a 47-year-old man who had an anterior communicating (A-com) artery aneurysm with two daughter sacs. We successfully placed two microcatheters in the direction of each sac to make more stable framing by referring to 3D fusion images after the first microcatheter was positioned. In both cases, microcatheter reshaping was necessary because of the vessel and aneurysm anatomy. We have used this technique successfully in 15 patients, for both ruptured and unruptured aneurysms. The average number of microcatheter reshaping was 1.3 times.

Conclusion: This method provides effective microcatheter reshaping for coil embolization of aneurysms, particularly those with differences between the axis of the parent artery and the vertical axis of aneurysm, or with a tortuous proximal artery.