Safety and Efficacy of Management for Intraprocedural Rupture During Endovascular Treatment for Intracranial Aneurysms.

BACKGROUND AND OBJECTIVES: Although intraprocedural rupture (IPR) is rare, it is a devastating complication of endovascular treatment (EVT) for intracranial aneurysms. Very few studies have been conducted on IPR, and the safety and efficacy of management techniques of IPR have not been investigated. METHODS: Patients who experienced IPR during EVT between 2013 and 2022 were enrolled from a multicenter observational registry. We examined the safety and efficacy of the management of IPR using imaging markers, including increased hemorrhage and ischemic lesions, which were evaluated using postoperative computed tomography and diffusion-weighted imaging, respectively. RESULTS: Of the 3269 EVTs for intracranial aneurysms, 74 patients who experienced IPR (2.26%) were analyzed. Fifty-five patients (3.36%) experienced IPR among 1636 EVT cases for ruptured aneurysms. Multivariate analysis revealed that increased hemorrhage was significantly associated with poor outcomes (odds ratio [OR], 6.37 [95% CI, 1.00-40.51], P = .050), whereas ischemic lesions were not. Regarding management techniques of IPR, antihypertensive medication use was significantly associated with increased hemorrhage (OR, 14.16 [95% CI, 2.35-85.34], P = .004). Heparin reversal was an independent factor for ischemic lesions (OR, 8.92 [95% CI, 1.54-51.58], P = .014). CONCLUSION: Although the setting of IPR may be miscellaneous, and optimal management varies depending on individual cases, heparin reversal might be associated with ischemic complications, and its role in the successful hemostasis in IPR during EVT for ruptured aneurysms remains unclear.

Efficacy of Endovascular Treatment for Distal Anterior Cerebral Artery Aneurysms: A Multicenter Observational Study.

OBJECTIVES: Distal anterior cerebral artery (DACA) aneurysms account for 1%-9% of all intracranial aneurysms. Microsurgical treatment is generally preferred for DACA aneurysms; however, it presents challenges owing to the anatomical complexities. Advances in neuro-interventional techniques have yielded promising results. This study aims to compare the clinical outcomes of DACA aneurysms treated with microsurgery and endovascular treatment (EVT) to elucidate the efficacy of EVT. MATERIALS AND METHODS: A multicenter observational registry comprising 16 stroke centers was utilized for this study. Data was retrospectively and prospectively analyzed from 166 patients with DACA aneurysms in our database, which included 4,552 consecutive patients with ruptured or unruptured intracranial aneurysms who underwent microsurgical or endovascular treatment between January 2013 and December 2021. RESULTS: Surgical clipping was performed in 115 patients, and 51 underwent coil embolization. The median follow-up duration was 15.3 months. No significant differences were observed in patient characteristics between the two treatment modalities. There were no differences in complication-related morbidity between the microsurgical treatment and EVT groups in either unruptured (10.5% vs. 9.1%, p=1.00) or ruptured aneurysms (5.2% vs. 6.9%, p=0.66). Coil embolization resulted in higher recurrence and retreatment rates than surgical clipping did, especially for ruptured aneurysms (2.6% vs. 27.6%, p<0.01). CONCLUSIONS: Endovascular treatment is an alternative to microsurgery for DACA aneurysms especially in unruptured cases or the patients who have difficulty undergoing craniotomy due to their general condition, albeit with considerations for higher recurrence and retreatment rates, particularly in ruptured cases. Close follow-up is crucial for the effective management of these challenges. Further studies are needed to refine the treatment strategies for DACA aneurysms.

Validity of the Cost-Effectiveness of Middle Meningeal Artery Embolization Following Hematoma Evacuation for Initial Chronic Subdural Hematoma.

BACKGROUND: Despite numerous articles about middle meningeal artery embolization (MMAE) highlighting its efficacy and safety for recurrent chronic subdural hematoma (CSDH), the appropriateness of adjunctive MMAE after hematoma evacuation for initial CSDH remains unclear from a cost-effectiveness perspective. METHODS: Patients with CSDH were enrolled in this study and were prospectively divided into 2 groups: the "conventional treatment" group, which was treated with hematoma evacuation alone, and the "MMAE" group, which was treated with adjunctive MMAE after hematoma evacuation. The proportion of patients requiring retreatment, length of hospital stay, economic costs, and modified Rankin Score were compared between the 2 groups. RESULTS: In this study, 53 cases were included, with 30 classified into the conventional treatment group and 23 classified into the MMAE group. In the conventional treatment group, the proportion of patients who required surgical retreatment was higher than that in the MMAE group (16.7% vs. 8.7%). The relative risk was 0.522 (95% confidence interval, 0.111-2.45). Although the addition of MMAE increased the cost per hospitalization by 26%, the increase in cost per patient was limited to 12%, owing to the reduction in patients who relapsed and required a second hospitalization. The increase in cost was not statistically significant. The MMAE group had a significantly higher proportion of patients with favorable outcomes (modified Rankin Score 0-2) (56.7% vs. 87.0%, P = 0.0328). CONCLUSIONS: By minimizing the increase in hospitalization days and procedure costs, MMAE following hematoma evacuation for initial CSDH could decrease the retreatment rate and balance the total medical costs associated with MMAE.

Contact aspiration for basilar artery occlusion safely reduces the puncture-to-recanalization time.

OBJECTIVE: Effective thrombectomies in the posterior circulation remain controversial. Previous reports have demonstrated the superiority of contact aspiration in anterior circulation. Aspiration catheters and stent retrievers are often used alone on a global scale, while combined techniques are commonly used in Japan. This study evaluated the effect of first-line contact aspiration with other strategies for the treatment of basilar artery occlusion. METHODS: The primary outcome was the frequency of the first-pass effect, and the secondary outcome was the time from puncture to the first-pass effect. A multicenter observational registry including 16 Japanese stroke centers was used. Between December 2013 and February 2021, enrolled patients underwent endovascular thrombectomy for basilar artery occlusion. The efficacy of contact aspiration compared to other methods (including stent retrievers and combined techniques) was evaluated. RESULTS: Eighty-four patients were included, all of whom had achieved effective recanalization. Twenty-six patients were treated with contact aspiration, 13 with combined technique, and 45 with stent retrievers. The two groups: contact aspiration and non-contact aspiration, had different backgrounds. Both had similar frequencies of effective recanalization and first-pass effects. The contact aspiration group experienced better functional outcomes without statistical significance, while this strategy was significantly associated with a shorter puncture-to-recanalization time (38 vs. 55 minutes, P=0.036). In particular, in the 55 patients with the first-pass effect, multivariate Cox proportional hazard analysis showed that contact aspiration was significantly associated with a shorter time from puncture to first-pass effect, independent of age and etiology of large-artery atherosclerosis (hazard ratio 2.02, 95% confidence intervals 1.10-3.69, P=0.023). CONCLUSION: This study suggested that contact aspiration for basilar artery occlusion may shorten the puncture-to-first-pass effect, compared to stent retrievers and combined techniques.

Two-Step Effective Onyx Embolization from the Occipital Artery for the Treatment of Intracranial Dural Arteriovenous Fistula: A Technical Note.

AIM: To report our experience and the technique of two-step effective Onyx embolization from occipital artery (OA) for the obliteration of dural arteriovenous fistulas (DAVFs) with OA feeders. MATERIAL AND METHODS: The medical records of patients with intracranial DAVFs treated with trans-arterial embolization (TAE) using Onyx from the OA were retrospectively reviewed. RESULTS: Seven patients were included. The methods of Onyx injection from the OA were categorized as simple Onyx injection into the shunt, and two-step embolization. Two-step embolization involved the Onyx or coil embolization of the OA distal to the branching site of the feeders in the first step, and Onyx was injected toward the target shunt in the second step. Simple Onyx injection was performed in two cases; in both cases, the residual shunt remained. By contrast, the two-step embolization technique was performed in five cases, and in all those cases, sufficient embolization of the DAVFs was achieved. CONCLUSION: Prior embolization using Onyx or coil of the distal OA helped prevent Onyx from unexpected embolization through the subcutaneous branches that were not associated with the shunt, thereby leading to effective embolization. This new two-step embolization technique from the OA may improve the obliteration rate of DAVFs with OA feeders using TAE with Onyx.

A Novel Braided Stent With Customized Simulation Software for Treatment of Intracranial Aneurysms: Multicenter Prospective Trial Before Unrestricted Clinical Application.

BACKGROUND AND OBJECTIVES: Planning/guidance software became important tools for physicians' presurgical optimal decision-making. However, there are no intracranial stent products with specifically associated simulation software. We report the "premarket" clinical trial of a new braided stent with a customized simulation software. METHODS: A stent system with 3 mesh density types (16, 24, and 32 wire mesh) was designed based on computational flow dynamics technology, and a simulation software (virtual stent planner [VSP]) was developed for the optimal stent deployment planning. Stents were selected after simulation on preoperative 3D-processed angioimages, and accuracy of the VSP was evaluated. RESULTS: Thirty-three unruptured intracranial aneurysms were successfully treated with VSP guidance. Twenty aneurysms (61%) were anterior circulation aneurysms, and 13 (39%) were posterior circulation aneurysms. The average aneurysm size was 7.1 mm, and the mean follow-up period was 19.2 months (11-39.0). There was no major recurrence or retreatment during follow-up, 2 morbidity cases, and no mortality. VSP planning presented slightly smaller stent dimensions compared with postdeployment: 24.2 vs 25.5 mm average, error -1.3 mm, and difference rate-5.46%. CONCLUSION: Based on this result, the new stents and software guidance system were approved by the Ministry of Health and Welfare as a combined medical device. VSP provided precise deployment with minimal error compared with actual stent and can contribute to better stent deployment even for less experienced physicians.

Imaging predictors of clinical outcomes after endovascular treatment in MRI-selected patients with acute basilar artery occlusion.

PURPOSE: We aimed to investigate the impact of baseline infarct area and collateral status (CS), which are imaging predictors of clinical outcome following stroke, after endovascular treatment (EVT) in MRI-selected patients with acute basilar artery occlusion (BAO). METHODS: Patients with acute BAO who underwent EVT within 24 h after stroke from December 2013 to February 2021 were included in this retrospective, multicenter, observational study. The baseline infarct area was evaluated by the posterior circulation of Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS) using diffuse-weighted imaging (DWI), and CS was assessed by measuring the computed tomography angiography of the basilar artery (BATMAN) score and the posterior circulation collateral score (PC-CS) using magnetic resonance angiography (MRA). A Good outcome was defined as a modified Rankin scale score ≤ 3 at 3 months. For each imaging predictor, a multivariate logistic regression analysis was performed to evaluate its impact on good outcomes. RESULTS: A total of 86 patients were analyzed, and 37 (43.0%) had a good outcome. The latter showed significantly higher pc-ASPECTS than those without good outcomes. In multivariate analyses, a pc-ASPECTS ≥ 7 was significantly associated with good outcomes (OR, 2.98 [95% CI, 1.10-8.13], P = 0.032), while PC-CS ≥ 4 (OR, 2.49 [95% CI, 0.92-6.74], P = 0.073) and BATMAN score ≥ 5 (OR, 1.51 [95% CI, 0.58-3.98], P = 0.401) were not. CONCLUSIONS: In MRI-selected patients with acute BAO, pc-ASPECTS on DWI was an independent predictor of clinical outcomes after EVT, while the MRA-based CS assessments were not.

Influence of Bilateral Cerebellar Infarction on Functional Outcome After Endovascular Treatment for Basilar Artery Occlusion.

BACKGROUND AND PURPOSE: To measure the magnitude of the effect of the infarct location measured using the posterior circulation Alberta Stroke Program Early Computed Tomographic Score (pc-ASPECTS) on the functional outcome at 90 days in patients with basilar artery (BA) occlusion undergoing endovascular therapy (EVT). METHODS: Of the acute ischemic stroke patients undergoing EVT for acute posterior circulation large vessel occlusion enrolled in the multicenter observational registry from December 2013 to February 2021, patients with BA occlusion were included. A favorable outcome was defined as achieving a modified Rankin Scale score of 0-3 at 90 days. The effect of pc-ASPECTS including the distribution on favorable outcomes was evaluated. RESULTS: One hundred patients were analyzed. Fifty-one patients (51%) achieved favorable outcome. Patients achieving a favorable outcome were younger, had a lower National Institutes of Health Stroke Scale score before EVT, and had a higher pc-ASPECTS before EVT than those not achieving a favorable outcome. Multivariable logistic analysis showed a significant association between higher pc-ASPECTS and a favorable outcome (odds ratio [OR] 1.24; 95% confidence interval [CI] 1.02-1.52; P = 0.028). Considering the infarct location, bilateral cerebellar infarction was significantly associated with a lower frequency of favorable outcomes than those without cerebellar infarction (OR 0.16; 95% CI 0.04-0.51; P = 0.002). CONCLUSIONS: A higher pc-ASPECTS before EVT could be a predictor of a favorable outcome after EVT for BA occlusion. In particular, the presence of bilateral cerebellar infarction before EVT was significantly associated with a lower likelihood of a favorable outcome.

P2Y12 reaction units and ischemic and bleeding events after neuro-endovascular treatment.

BACKGROUND AND PURPOSE: To investigate the associations of perioperative P2Y12 reaction units (PRU) measured using VerifyNow with ischemic and bleeding events, and to determine the PRU threshold in the setting of elective neuro-endovascular treatment (EVT) for intracranial/extracranial vascular disease in patients taking aspirin and clopidogrel. METHODS: Of the patients undergoing elective neuro-EVT while taking aspirin and clopidogrel, those taking both antiplatelet agents for 7 days or more and whose PRU and aspirin reaction units (ARU) were measured were included. The primary and safety outcomes were defined as symptomatic ischemic and major bleeding events within 30 days after EVT. RESULTS: A total of 197 patients were available for the analyses. Higher PRU was associated with symptomatic ischemic events on multivariable logistic analysis (odds ratio per 10 increase 1.14 [95% confidence interval 1.03-1.27], p=0.011). Receiver operating characteristic curve analysis showed that PRU ≥212 was the threshold to predict symptomatic ischemic events (area under the curve=0.73; sensitivity, 62.5%; specificity, 82.0%). Lower PRU was also associated with major bleeding events (odds ratio per 10 increase 0.87 [0.78-0.96], p=0.004), and the threshold to predict major bleeding events was PRU ≤46 (area under the curve=0.76; sensitivity, 70.0%; specificity, 87.2%) CONCLUSIONS: The PRU value was associated with symptomatic ischemic and major bleeding events after elective neuro-EVT in patients taking aspirin and clopidogrel. PRU ≥212 and PRU ≤46 appeared to be the threshold values to predict symptomatic ischemic and major bleeding events, respectively.

Endovascular Treatment for Acute Ischemic Stroke After Video-Assisted Thoracoscopic Pulmonary Lobectomy in Patients With Lung Cancer: A Report of Four Cases and Literature Review.

BACKGROUND: Postoperative cerebral embolic stroke is a serious complication of pulmonary lobectomy, occurring in 1.1% of patients undergoing lobectomy through video-assisted thoracoscopic surgery (VATS). The mechanism of this complication is thought to be embolic stroke caused by thrombus formed due to stagnation in the pulmonary vein stump after VATS lobectomy. There have been few reports demonstrating the utility of endovascular treatment (EVT) for cerebral embolic stroke after VATS lobectomy. CASE DESCRIPTION: In our case series, cerebral embolic stroke occurred after VATS pulmonary lobectomy for lung cancer, including the left upper lobe in three cases and the right lobe in one. The median duration of ischemic stroke after VATS was 4.5 days (interquartile range, 2-9 days). The median time from stroke onset to puncture was 130 min. Successful recanalization was achieved in all cases, and two patients achieved favorable clinical outcomes (modified Rankin scale, 0-2). CONCLUSION: We report a case series of four patients who underwent EVT for acute embolic stroke after VATS lobectomy for lung cancer. EVT is considered a reasonable and feasible therapeutic option for this condition.

Clinical Course of Abducens Nerve Palsy in Patients with Ruptured Vertebral Artery Dissecting Aneurysms.

Objective: There are few detailed reports on abducens nerve palsy due to a ruptured vertebral artery dissecting aneurysm (VADA). We investigated the clinical characteristics and long-term course of abducens nerve palsy in ruptured VADA patients treated by endovascular surgery. Methods: Of the 51 cases of ruptured VADA treated by endovascular intervention from 2011 to 2019, 31 with a good/fair outcome, in which ocular motility disorder was able to be followed, were included and investigated. Results: In all, 11 patients (35.5%) had abducens nerve palsy, and the World Federation of Neurological Surgeons (WFNS) grade and Hunt & Hess (H&H) grade at the time of arrival of patients with abducens nerve palsy were significantly higher than those of patients without abducens nerve palsy. Of the 10 patients who were able to be followed, abducens nerve palsy in 3 completely recovered in 7-180 days. Abducens nerve palsy improved in five patients and remained in two patients. Conclusion: More severe neurological findings on admission reflect a higher rate of abducens nerve palsy. Diplopia induced by abducens nerve palsy is one of the most important sequelae of ruptured VADA, which impairs the daily activities of the patients. Some cases of abducens nerve palsy improve over a long period. Therefore, appropriate diagnosis and follow-up should be concerned.

Refractory in-stent stenosis after flow diverter stenting associated with delayed cobalt allergic reaction.

In-stent stenosis (ISS) triggered by a metal-induced allergic reaction of Pipeline embolization device (PED) placement is extremely rare. The present report describes a patient who presented with delayed parent artery occlusion and refractory ISS after PED placement due to cobalt allergy. A patient in her 70s underwent PED placement for a right internal carotid artery (ICA) large aneurysm; 4 months later, the patient presented with left-sided hemiparesis, and MRI revealed right ICA occlusion even though antiplatelet therapy was optimal. She underwent mechanical thrombectomy, and successful recanalization was achieved. However, follow-up angiography 6 months after the thrombectomy revealed severe ISS, and the patch testing showed a positive reaction for cobalt. As a result of long-term administration of oral steroids and antihistamine, progression of ISS was suppressed. It was supposed that a delayed hypersensitivity reaction to cobalt might induce refractory ISS after PED placement.

Combined Technique Thrombectomy with a Long Balloon-Guiding Catheter and Long Sheath Aids in Rapid and Stable Recanalization in Patients with Anterior Circulation Acute Ischemic Stroke.

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.

Mid-/Long-Term Outcome of Neuroendovascular Treatment for Chronic Carotid Artery Total Occlusion.

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.

Simulation Model of Arteriovenous Malformation Embolization Using Onyx.

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.

A Case of Idiopathic Intracranial Hypertension Treated by Transverse Sinus Stenting.

Objective: We report a patient with chronic headache due to idiopathic intracranial hypertension (IIH) associated with transverse sinus (TS) stenosis. The symptom improved after stent placement at the site of stenosis. Case Presentation: The patient was a 37-year-old woman with progressive headache and diplopia as chief complaints. She had severe bilateral papilledema. Magnetic resonance imaging (MRI) and angiography revealed stenosis of the bilateral TS. Lumbar puncture demonstrated raised intracranial pressure and IIH was tentatively diagnosed. Visual impairment progressed despite oral acetazolamide therapy. A venous pressure gradient was monitored during stent placement. The pressure gradient improved after stenting. Dual antiplatelet therapy was initiated 1 week before the procedure. Papilledema and headache resolved immediately after the procedure. No in-stent stenosis or occlusion occurred during the follow-up period. Conclusion: Stent placement for TS stenosis can improve the cerebral venous return in IIH patients. Although restenosis is possible, venous sinus stenting is considered an effective treatment.

Periprocedural Variability of Platelet Functions in Carotid Artery Stenting: An Analysis Using VerifyNow.

Objective: The assessment of platelet functions is necessary to prevent both thromboembolic and hemorrhagic complications under dual antiplatelet therapy (DAPT). Using the VerifyNow (Accumetrics, Inc., San Diego, CA, USA) assay, this study aimed to reveal time-dependent changes in platelet functions after carotid artery stenting (CAS). Methods: We enrolled retrospectively 43 patients who underwent CAS under DAPT. Aspirin reaction unit (ARU) and P2Y12 reaction unit (PRU) values were determined on the day before and on days 1, 3, and 7 after the procedure. Multiple comparison tests (MCTs) were performed among ARU and PRU measurement points, and the proportions of hypo- and hyper-responses were compared. Results: The median ARU values were 408 (interquartile range: 392-497) before CAS and 418 (405-470) on day 1, 405 (393.0-460.5) on day 3, and 402 (388.5-477.5) on day 7 (not significant in MCTs). The percentages of hypo-responses were 16.3%, 7.0%, 2.3%, and 7.0%, respectively (p = 0.11). The significantly different median PRU values were 173 (116.5-209.5), 233 (166.5-273.5), 139 (70.5-205.5), and 51 (9.0-79.5), respectively. The median PRU was before the procedure within the therapeutic range but exceeded the upper cutoff on day 1 and was below the lower cutoff on day 7. The percentages of hypo-responses were 14.0%, 51.2%, 18.6%, and 11.6%, respectively (p <0.001) and the percentages of hyper-responses were 9.3%, 2.3%, 23.3%, and 62.8%, respectively (p <0.001). Conclusion: In the periprocedural CAS period, ARU values were stable, but PRU values showed time-dependent changes. PRU values were above the therapeutic range the day after CAS but decreased below this range on day 7.

In Vitro Modeling of Human Brain Arteriovenous Malformation for Endovascular Simulation and Flow Analysis.

BACKGROUND: Current in vitro models for human brain arteriovenous malformation (AVM) analyzing the efficacy of embolic materials or flow conditions are limited by a lack of realistic anatomic features of complex AVM nidus. The purpose of this study was to evaluate a newly developed in vitro AVM model for embolic material testing, preclinical training, and flow analysis. METHODS: Three-dimensional (3D) images of the AVM nidus were extracted from 3D rotational angiography from a patient. Inner vascular mold was printed using a 3D printer, coated with polydimethylsiloxanes, and then was removed by acetone, leaving a hollow AVM model. Injections of liquid embolic material and 4-dimensional (4D) flow magnetic resonance imaging (MRI) were performed using the AVM models. Additionally, computational fluid dynamics analysis was performed to examine the flow volume rate as compared with 4D flow MRI. RESULTS: The manufacture of 3D in vitro AVM models delivers a realistic representation of human nidus vasculature and complexity derived from patients. The injection of liquid embolic agents performed in the in vitro model successfully replicated real-life treatment conditions. The model simulated the plug and push technique before penetration of the liquid embolic material into the AVM nidus. The 4D flow MRI results were comparable to computational fluid dynamics analysis. CONCLUSIONS: An in vitro human brain AVM model with realistic geometric complexities of nidus was successfully created using 3D printing technology. This AVM model offers a useful tool for training of embolization techniques and analysis of hemodynamics analysis, and development of new devices and materials.

Computational Fluid Dynamics Analysis of the Offending Artery at Sites of Neurovascular Compression in Trigeminal Neuralgia Using Preoperative MRI Data.

This study aimed to analyze the hemodynamic features of the offending artery at sites of neurovascular compression (NVC) using computational fluid dynamics (CFD). A total of 23 patients who underwent microvascular decompression (MVD) for primary trigeminal neuralgia (TN) between January 2015 and December 2016 were enrolled in this study. The compressing vessel at the NVC site was identified microsurgically in all cases, and patients were divided into two groups based on the intraoperative findings: (1) the arterial NVC group and (2) the non-arterial NVC control group. A 3D surface model of the structures surrounding the NVC was created using preoperative magnetic resonance imaging (MRI), and CFD analysis was performed for the target artery. In addition to standard parameters, such as the wall shear stress (WSS), flow velocity, and pressure, we calculated the WSS ratio (WSSR) by dividing the WSS at the NVC by the mean WSS of the target. Arterial compression was observed intraoperatively in 13 patients. The mean WSSR of the arterial NVC group was significantly higher than that of the control group (2.36 ± 1.00 vs. 1.18 ± 0.73, P <0.05). There were no significant intergroup differences in the other calculated parameters. High WSSR, which indicates elevated WSS at the sites of NVC, was identified as a unique parameter of arterial compression that may contribute to TN. CFD could be a useful clinical tool in determining the target of MVD under preoperative conditions.

Precision microcatheter shaping in vertebrobasilar aneurysm coiling.

BACKGROUND: Inventing an optimal curve on a microcatheter is required for successful intracranial aneurysm coiling. Shaping microcatheters for vertebrobasilar artery aneurysm coiling is difficult because of the vessel's long, tortuous and mobile anatomy. To overcome this problem, we devised a new method of shaping the microcatheter by using the patient's specific vessel anatomy and the highly shapable microcatheter. We report our preliminary results of treating posterior circulation aneurysms by this method. METHODS: An unshaped microcatheter (Excelsior XT-17; Stryker Neurovascular, Fremont, CA, USA) was pretreated by exposure to the patient's vessel for five minutes. The microcatheter was placed in the vicinity of the targeted aneurysm and was left in contact with the patient's vessel before extraction. This treatment precisely formed a curve on the microcatheter shaft identical to the patient's vessel anatomy. Following the pretreatment, the tip of the microcatheter was steam shaped according to the long axis of the target aneurysm. Five consecutive vertebrobasilar aneurysms were treated using this shaping method and evaluated for the clinical and anatomical outcomes and microcatheter accuracy and stability. RESULTS: All of the designed microcatheters matched the vessel and aneurysm anatomy except in one case that required a single modification. All aneurysms were successfully catheterized without the assistance of a microguidewire, and matched the long axis of the aneurysm. All microcatheters retained stability until the end of the procedure. CONCLUSIONS: A precise microcatheter shaping for a vertebrobasilar artery aneurysm may be achieved by using the patient's actual vessel anatomy and the highly shapable microcatheter.