Treatment Results of Carotid Artery Stenting with an Open-Cell Stent: Analysis of 734 Consecutive Cases at a Single Center.

OBJECTIVE: In carotid artery stenting (CAS) for internal carotid artery stenosis, the stent is often selected according to the plaque properties and arterial tortuosity. In our institute, an open-cell stent is used as the first-line stent regardless of the characteristics of the lesion. This study was performed to examine the outcome of CAS with an open-cell stent as the real-world results. METHODS: In total, 811 CAS procedures using open-cell stents were performed for internal carotid artery stenosis from April 2002 to December 2019. Of these patients, we excluded those with hyperacute conditions for which CAS was performed within 3 days of onset, those in whom acute mechanical thrombectomy was performed simultaneously with CAS, and those with stenosis due to arterial dissection. Thus, 734 patients were retrospectively analyzed. Perioperative and long-term outcomes and risk factors for perioperative infarction were investigated. RESULTS: The periprocedural stroke rate and mortality rate were 3.7% (27/734) and 0.4% (3/734), respectively. Low-echoic plaque was a significant risk factor for periprocedural stroke in both univariate (P < 0.03) and multivariate (odds ratio, 2.69; 95% confidence interval, 1.14-6.66; P = 0.02) analyses. Cerebral infarction and high grade restenosis were observed in 15 (2.0%) and 17 (2.3%) patients during a median 50-month follow-up. CONCLUSIONS: CAS with open-cell stents showed good results in terms of both the postoperative stroke incidence and long-term severe restenosis rate. However, low-echoic plaque was a risk factor for perioperative stroke incidence, which should be considered when deciding on the indication for CAS with an open-cell stent.

Middle meningeal artery embolization for chronic subdural hematoma: a systematic review.

Background: Chronic subdural hematoma (cSDH) is one of the most common diseases in neurosurgery. Middle meningeal artery embolization (MMAE) is reportedly an option to prevent recurrence or avoid surgery in patients with cSDH. This study was performed to review the evidence on MMAE for cSDH and evaluate its safety, efficacy, indications, and feasibility. Methods: We systematically reviewed the literature according to the PRISMA guidelines using an electronic database. The search yielded 43 articles involving 2,783 patients who underwent MMAE. Results: The hematoma resolution, recurrence, and retreatment rates in the MMAE-alone treatment group (n = 815) were 86.7%, 6.3%, and 9.6%, respectively, whereas those in the prophylactic MMAE with combined surgery group (n = 370) were 95.6%, 4.4%, and 3.4%, respectively. The overall MMAE-related complication rate was 2.3%. Conclusion: This study shows that MMAE alone is, although not immediate, as effective as evacuation surgery alone in reducing hematoma. The study also shows that combined treatment has a lower recurrence rate than evacuation surgery alone. Because MMAE is a safe procedure, it should be considered for patients with cSDH, especially those with a high risk of recurrence.

First-in-human trial of Center Wire for neuroendovascular therapy to avoid guidewire-related complications.

BACKGROUND: An exchange maneuver is useful for the delivery of devices to target vessels. However, hemorrhagic complications can occur due to vessel perforation during an exchange maneuver. In addition, the exchange is often challenging due to unfavorable anatomy. Center Wire is an exchange-length wire with a nondetachable stent that was developed to improve navigation and stability during exchange maneuvers. The aim of this study is to investigate the safety and efficacy of Center Wire of the anchor wire technique during neuroendovascular treatment. METHODS: Ten patients with intracranial aneurysms were treated after signing a Certified Review Board-approved consent. Anchor wire technique was used in all patients to navigate catheters to the target vessel for aneurysm treatment. RESULTS: Anchor wire technique was successfully applied in all 10 cases using Center Wire. One device-related incident of vasospasm occurred which was asymptomatic. No device-related dissection, perforation, or thromboembolic events occurred. One patient had intraoperative aneurysm rupture during coil placement which was treated immediately without clinical consequences. Two patients had postoperative ischemic strokes due to thrombotic occlusion of branches originating from the aneurysm which were unrelated to the device. CONCLUSIONS: This first-in-human trial of Center Wire demonstrated the safety and efficacy of the anchor wire technique for neuroendovascular treatment in a strictly regulated prospective registry trial.

Predictive factors for improvement of symptomatic cerebral vasospasm following subarachnoid hemorrhage by selective intra-arterial administration of fasudil hydrochloride.

BACKGROUND: Symptomatic cerebral vasospasm after subarachnoid hemorrhage (SAH) is a significant cause of delayed cerebral ischemia that leads to poor outcomes. Selective intra-arterial administration of fasudil hydrochloride (IAF) has been adopted for its vasodilatory effect on spasm arteries to prevent delayed cerebral ischemia. However, its effect on clinical outcomes and predictive factors for good recovery are not fully understood. This study aimed to investigate the outcomes of selective IAF and identify predictive factors for good outcomes in patients with cerebral vasospasm after SAH. METHODS: A retrospective study of 36 patients with cerebral vasospasm following SAH who underwent selective IAF at our institution between January 2014 and May 2022 was conducted. We evaluated the improvements in neurological findings before and after selective IAF. Statistical analyses were performed to determine factors associated with good outcomes. RESULTS: Selective IAF improved the neurological findings in 26 patients (72.2%). Pre-therapeutic absence of cerebral infarction in more than 1/3 of the spasm artery perfusion area was significantly associated with an improvement in neurological findings (p < 0.0001). Furthermore, there was a tendency for a good outcome when the age was younger (p = 0.093), and the spasm was limited to peripheral vessels (p = 0.065). CONCLUSION: Our study indicates that selective IAF has a promising effect in improving symptomatic vasospasm, except when a large cerebral infarction exists in the spasm artery perfusion area. Early consideration of selective IAF could be recommended once patients experience symptomatic cerebral vasospasm after SAH.

PulseRider-assisted coil embolization for an unruptured internal carotid artery-persistent primitive trigeminal artery aneurysm.

A persistent primitive trigeminal artery (PPTA) is a vessel remnant of carotid-vertebrobasilar anastomosis. The aneurysm at the bifurcation of the internal carotid artery (ICA) and PPTA tends to have a broad neck with the branch incorporated into the sac. Because PPTA supplies to the posterior circulation and branches off direct pontine perforators, PPTA preservation should always be considered when treating PPTA aneurysms to avoid ischemic complications.We report a case of the wide-neck ICA-PPTA aneurysm successfully treated with the PulseRider-assisted coil embolization, resulting in complete occlusion with PPTA patency. Relevant anatomy and endovascular strategy of the PPTA aneurysms are discussed.

Coagulation Technique for Remodeling Anastomosis Spaces in Bypass Surgery.

Cerebrovascular bypass techniques are the current cornerstone methods to achieve cerebral revascularization for moyamoya disease or syndrome and select cases of vascular pathologies, such as intracranial atherosclerotic occlusive disease and complex aneurysms. Factors influencing bypass efficiency include graft patency, short temporary occlusion time, and precise anastomosis. On the basis of our senior author's vast experience with 1300 bypasses, we recommend performing the anastomosis with the minimal number of stitches as achievable to avoid stenosis of the artery's internal lumen that may occur with unnecessary, additional stitches, preserving patency. After completing the anastomosis, when a leak occurs between the sutures, cottonoid tamponade, hemostatic materials, or adding 1 or 2 sutures to the space is often enough to close the gap. However, additional suture placement can be difficult, which might cause stenosis of the anastomosis and reduce blood flow. In this video, we introduce a bipolar coagulation technique for remodeling the anastomosis orifices, as an alternative manner, when minor leakages occur between the knots (Video 1). We demonstrate this technique in an adult moyamoya disease patient who underwent a superficial temporal artery-to-middle cerebral artery bypass, in this case coagulation of the donor artery wall at the anastomosis made possible to adapt the edges of the donor artery precisely to the recipient artery wall by shrinking its redundancy between the stitches. The most important task is to coagulate the donor side orifice precisely with low-power bipolar coagulation and never coagulate the recipient artery. This coagulation technique is a simple alternative to stop further leakage, and it prevents placing an additional suture and reduces temporary occlusion time.

Comparison of Symptomatic Vasospasm after Surgical Clipping and Endovascular Coiling.

Vasospasm, initial neurological damage, rebleeding, and periprocedural complications are associated prognostic factors for clinical outcomes after aneurysmal subarachnoid hemorrhage (SAH). In this study, factors related to delayed ischemic neurological deficit (DIND) are evaluated using data from our institute for the last 18 years. Data from 2001 to 2018 of patients with aneurysmal SAH who underwent surgical clipping (SC) or endovascular coiling (EC) within 7 days of onset were retrospectively analyzed. Cases of mortality within 5 days after treatment were excluded. Multivariate analysis was used to identify the risk factors for DIND. In total, 840 cases of SAH were assessed; among these cases, 384 (45.7%) and 456 (54.3%) were treated with SC and EC, respectively. The frequency of DIND in the EC group was significantly less than that in the SC group (11.8% vs. 17.7%; p = 0.016). In the results of multivariate analysis, internal carotid artery (ICA) aneurysm and hemorrhagic complications were the risk factors for DIND. Cilostazol administration and EC were significant factors for vasospasm prevention after aneurysmal SAH (odds ratio of ICA aneurysm: 1.59, hemorrhagic complications: 1.76, SC: 1.51, and cilostazol administration: 0.51, respectively). Cilostazol administration was also a significant factor in patients who were treated with EC. ICA aneurysm, treatment strategy, hemorrhagic complications, and cilostazol administration were associated with DIND. Oral administration of cilostazol and avoiding hemorrhagic complications were effective in DIND prevention. If both treatments are available for ruptured aneurysms, clinicians should choose EC on the basis of its ability to prevent DIND.

Pipeline flow diversion with adjunctive coil embolization for internal carotid artery aneurysms following an intradural component: results in 46 consecutive aneurysms from a Japanese single-center experience.

In the treatment of an intracranial aneurysm with the flow diverter, the combined use of coil embolization can help promote subsequent progressive thrombosis within the aneurysm sac and reduce the risk of delayed aneurysm rupture. This study retrospectively reviewed outcomes of patients who had undergone the Pipeline Embolization Device (PED) with adjunctive coil embolization (PED/coil) at a single center to determine its safety and efficiency. Patients with internal carotid artery aneurysms following an intradural component were selected for PED/coil between 2015 and 2020. All patients were premedicated with dual antiplatelet therapy of aspirin plus clopidogrel or prasugrel. A minimal number of PEDs were deployed, with coils inserted using a stent-jail technique, avoiding dense packing. A total of 46 aneurysms (43 patients; median dome size, 11.6 mm; median neck width, 6.3 mm) were treated with PED/coil. The median volume embolization ratio was 14.8%. The degree of angiographic filling at the 6-month and latest angiography showed complete occlusion in 60.5% (26/43) and 70.5% (31/44), respectively. Small (< 10 mm) aneurysms achieved a higher complete occlusion rate in the early period; a lower cumulative incidence of aneurysm occlusion was observed in large and giant (≥ 10 mm) aneurysms (P = .024). The median clinical follow-up was 22 months, and no aneurysm ruptures occurred. Favorable clinical outcomes were achieved, with permanent neurological morbidity of 4.7% and no mortality. PED/coil demonstrated a high angiographic occlusion rate at an early stage. Loosely packed coils are sufficient to obliterate aneurysms effectively.

Isolated progression of miliary brain metastasis in a patient with stable lung adenocarcinoma successfully treated with whole-brain radiotherapy: A case report.

Miliary brain metastasis is a rare form of metastasis commonly associated with advanced stages of cancer. In this article, we report a case of a 38-year-old male with solitary progression of miliary brain metastasis originating from stage 4 EML-ALK-positive lung adenocarcinoma. Multiple brain lesions were first detected upon the patient's inclusion in a brigatinib clinical trial. The brain lesions dissipated, and the lung and bone lesions decreased in size after starting the brigatinib therapy; however, the brain lesions later increased in number. A biopsy revealed miliary brain metastasis of lung adenocarcinoma. The patient was successfully treated with whole brain therapy, in addition to brigatinib. This case suggests that it is possible for an isolated miliary brain metastasis to occur during the effective suppression of systemic cancer progression. Whole brain radiotherapy while continuing effective systemic therapy is a good strategy for such patients.

A Damp-and-Push Technique for the Copolymer (Onyx) Embolization of Dural Arteriovenous Fistula.

BACKGROUND: Copolymer (Onyx) embolization is an effective treatment for dural arteriovenous fistula (dAVF), however, some dAVFs have multiple, high-flow feeding vessels, resulting in insufficient embolization. For the treatment of such patients, we have developed a novel flow-control technique, the 'damp-and-push technique'. The purpose of this study was to evaluate the technical efficiency and safety of this technique. METHODS: Seven patients who had been diagnosed with intracranial dAVF were treated by transarterial Onyx embolization using the damp-and-push technique between 2016 and 2019. This technique was designed to reduce blood flow to the shunt site using a balloon catheter in the major feeding vessel other than the one injected with Onyx, leading to better Onyx penetration and enabling more controlled embolization of complex dAVFs. Retrospectively collected data were reviewed to assess the occlusion rates and clinical outcomes. RESULTS: The dAVF was at a transverse sinus-sigmoid sinus junction in four patients, in the superior sagittal sinus in two, and in the tentorium in one. Five cases were Cognard type Ⅱb and two cases were Cognard type Ⅳ. All the patients were treated by transarterial Onyx injection via the main feeding vessel, combined with flow reduction in the other main feeding vessel using a balloon catheter. Complete occlusion was achieved in six patients and elimination of cerebral venous reflux was achieved in all the patients. There were no immediate or delayed post-interventional complications. CONCLUSIONS: Transarterial Onyx embolization of dAVF using the damp-and-push technique is safe and yields a high complete occlusion rate.

High-flow bypass using saphenous vein grafts with trapping of ruptured blood blister-like aneurysms of the internal carotid artery: patient series.

BACKGROUND: Trapping an aneurysm after the establishment of an extracranial to intracranial high-flow bypass is considered the optimal surgical strategy for ruptured blood blister-like aneurysms (BBAs) of the internal carotid artery (ICA). For high-flow bypass surgeries, a radial artery graft is generally preferred over a saphenous vein graft (SVG). However, SVGs can be advantageous in acute-phase surgeries because of their greater length, easy manipulability, ability to act as high-flow conduits, and reduced risk of vasospasms. In this study, the authors presented five cases of ruptured BBAs treated with high-flow bypass using an SVG followed by BBA trapping, and they reported on surgical outcomes and operative nuances that may help avoid potential pitfalls. OBSERVATIONS: After the surgeries, there were no ischemic or hemorrhagic complications, including symptomatic vasospasms. In three of the five cases, postoperative modified Rankin scale scores were between 0 and 2 at the 3-month follow-up. In one case, the SVG spontaneously occluded after surgery while the protective superficial temporal artery (STA) to middle cerebral artery (MCA) bypass became dominant, and the patient experienced no ischemic symptoms. LESSONS: High-flow bypass using an SVG with a protective STA-MCA bypass followed by BBA trapping is a safe and effective treatment strategy.

Carotid artery stenting before surgery for carotid artery occlusion associated with acute type A aortic dissection: Two case reports.

BACKGROUND: We experienced two cases of ischemic stroke resulting from carotid artery occlusion associated with acute type A aortic dissection (ATAAD), in which carotid artery stenting before the surgery for ATAAD resulted in good clinical outcomes.Case 1 description: A 63-year-old woman was hospitalized for conscious disturbance, right hemiparesis, and total aphasia. Computed tomography of the head showed no abnormal findings. Computed tomography angiography showed ATAAD and bilateral common carotid artery occlusion. Surgery was not indicated for ATAAD because of a poor prognosis of ischemic stroke. However, carotid artery stenting of the left common carotid artery occlusion was successfully performed, and her neurological findings improved. The patient underwent hemiarch replacement for ATAAD on the day after carotid artery stenting. Her final modified Rankin Scale was 1. Case 2 Description: A 57-year-old woman was hospitalized for mild left hemiparesis. Magnetic resonance imaging showed right watershed infarction and right common carotid artery occlusion. Computed tomography angiography showed ATAAD. After hospitalization, conscious disturbance appeared and left hemiparesis worsened. Ischemic stroke indicated a poor prognosis for revascularization by surgery for ATAAD. Thus, carotid artery stenting of the right common carotid artery occlusion was performed. The patient's neurological findings improved and she underwent hemiarch replacement for ATAAD at 19 days after carotid artery stenting. Her final modified Rankin Scale was 1. CONCLUSIONS: In the present cases, although ischemic stroke was serious and precluded surgical indication for ATAAD, carotid artery stenting before surgery for ATAAD resulted in good clinical outcomes. Performing carotid artery stenting before surgery for ATAAD is challenging but achievable, and is a valid treatment option depending on the individual cases.

Multiple Cerebral Hemorrhages With Microbleeds in Intravascular Large B-Cell Lymphoma.

This is an extremely rare reported case of intravascular large B-cell lymphoma (IVLBCL) presenting with acute hemorrhages and numerous microbleeds. An 80-year-old man presented with consciousness disturbances after convulsion. Computed tomography revealed multiple hemorrhages, and susceptibility-weighted imaging (SWI) demonstrated numerous microbleeds. Brain biopsy showed CD20-positive cells in small vessels; accordingly, IVLBCL was diagnosed. IVLBCL should be considered as a differential diagnosis in multiple cerebral hemorrhages and microbleeds.

Safety and efficacy of an open-cell stent and double-balloon protection for unstable plaques: analysis of 184 consecutive carotid artery stentings.

INTRODUCTION: In our institute, most cases of carotid artery stenosis are treated by carotid artery stenting (CAS) with an open-cell stent and double-balloon protection, even if plaques are unstable. This study was performed to examine the outcome of CAS with an open-cell stent and double-balloon protection for unstable plaques. METHODS: A total of 184 CAS procedures in our institute between October 2010 and February 2018 were assessed. Ultrasonography findings of low-echo plaques, plaque ulceration, or both were defined as unstable plaques. A plaque-to-muscle ratio (PMR) of >1.8 on T1-weighted black blood imaging using spin-echo was also defined as an unstable plaque. Seventy-four unstable plaques on ultrasonography and 86 unstable plaques evaluated by PMR were included. Open-cell stents and double-balloon protection (proximal balloon protection during lesion crossing and distal balloon protection after lesion crossing) were used in all cases. RESULTS: On ultrasonography, perioperative asymptomatic thromboembolization was significantly more frequent in the unstable plaque group (39/74, 52.7%) than in the stable plaque group (41/110, 37.3%, p=0.0384). Asymptomatic thromboembolization was also significantly more frequent in the PMR >1.8 group (44/86, 51.2%) than in the PMR <1.8 group (36/98, 36.7%, p=0.0489). However, symptomatic thromboembolization was rare (n=5, 2.7%), and all of these patients had minor stroke. During the 4-year follow-up, the risk of ipsilateral stroke was 0.28% and 0.27% per year in patients with symptomatic and asymptomatic lesions, respectively. CONCLUSIONS: The outcomes of CAS with an open-cell stent and double-balloon protection are acceptable. This method is effective and safe, even if carotid artery stenosis comprises unstable plaques.

Outcomes of Endovascular Therapy versus Microsurgical Treatment for Aneurysmal Subarachnoid Hemorrhage in Patients ≥70 Years of Age.

Purpose: This retrospective research aimed to compare the efficacy of endovascular therapy (EVT) versus microsurgical treatment (MST) for elderly patients with aneurysmal subarachnoid hemorrhage (aSAH). Methods: Elderly (>70 years) patients with aSAH who underwent aneurysm obliteration during 2007-2017 were selected from our hospital database and enrolled in this retrospective study. We reviewed each patient's background, the severity of the aSAH, and aneurysmal characteristics that compelled EVT or microsurgery treatment and then compared the two treatment groups. A favorable primary outcome was defined by a modified Rankin scale (mRS) score of 0-3 at hospital discharge. The 78 patients formed two cohorts (39 patients each) based on their propensity scores for EVT or MST. We estimated the adjusted odds ratio, followed by a sensitivity analysis of the original 201 patients (118 with EVT and 83 with MST). Results: In the propensity score-matched cohorts, favorable outcomes were observed in 33.3% and 7.7% of patients in the EVT and MST groups, respectively (p = 0.01). Results of the sensitivity analysis were similar to the main results. Conclusion: The clinical outcomes for the elderly aSAH patients were better in the EVT group than in MST group.

A Case of Subarachnoid Hemorrhage with Dissecting Aneurysm of the Anterior Choroidal Artery.

Objective: Dissecting aneurysms of the anterior choroidal artery (AchoA) are extremely rare, with only a few reported cases. Herein, we report an extremely rare case of subarachnoid hemorrhage with dissecting aneurysm of the AchoA. Case Presentation: A 68-year-old man was hospitalized for sudden onset of headache, progressive consciousness disorder, and right hemiparesis. He had a prior medical history of systemic lupus erythematosus (SLE), and was taking prednisolone (50 mg/day) for 15 months. CT showed subarachnoid hemorrhage in the left side of the basal cistern and Sylvian fissure. Left internal carotid artery (ICA) angiography revealed a fusiform aneurysm of the AchoA. He was diagnosed with a ruptured dissecting aneurysm of the AchoA because the shape of aneurysm was fusiform and there was laminar flow inside the aneurysm. Parent artery occlusion (PAO) was performed to prevent re-hemorrhage on the day of onset. Although ventricular drainage for acute hydrocephalus was performed after AchoA occlusion, his consciousness disorder did not improve. Postoperative angiography at 1-week recovery from the procedure revealed disappearance of the AchoA, including the dissecting aneurysm. However, he died following septic shock caused by pneumonia at 1 month after the procedure. Conclusion: We report an extremely rare case of subarachnoid hemorrhage with a dissecting aneurysm of the AchoA. Vasculitis caused by SLE and a vulnerability of the vessel wall following chronic steroid use are potential causes of the dissecting aneurysm of the AchoA.

[Treatment Strategies for Unruptured Multiple Intracranial Aneurysms].

OBJECTIVE: Unruptured aneurysms are often discovered incidentally on MRI. In some patients, multiple aneurysms cannot be treated with only craniotomy or endovascular surgery. When both craniotomy and endovascular surgery are deemed necessary, craniotomy is generally performed first because of the use of antiplatelet agents involved, followed by endovascular surgery several months later. However, no clear criteria for this treatment policy have been elicited. We investigated therapeutic outcomes in patients with aneurysms treated by craniotomy followed by endovascular surgery at our hospital. PATIENTS AND METHODS: This was a retrospective study including patients undergoing craniotomy clipping of one or more unruptured aneurysms at one site and endovascular surgery for those at a different site, between January 2012 and May 2018 in our hospital. The types of treatment, interval between treatments, complications, and other factors were analyzed. RESULTS: This study included 22 patients who underwent a total of 25 craniotomies and 23 endovascular surgeries. The mean time from final craniotomy to initial endovascular surgery was 118 days. Although treatment-related complications occurred in three patients, they were not associated with the time interval between craniotomy and endovascular surgery or the timing of the start of the antiplatelet therapy. CONCLUSIONS: The treatment was successful and was carried out safely and appropriately by first performing the craniotomy, followed by a set interval of time before starting the antiplatelet therapy, and then performing the endovascular surgery. Further studies analyzing more cases are required to establish the criteria better, such as the appropriate interval time between treatments.

[A Case of Intraosseous Meningioma Suspected of Osteosarcoma Based on Preoperative Image Examinations].

Intraosseous meningioma(IM)is one of the less frequent tumors of the skull, which often cannot be distinguished from other common skull tumors based on preoperative radiological findings. Herein, we describe a case of IM suspected to be an osteosarcoma based on preoperative image examinations. A 72-year-old woman experienced an impact to her left parietal area, and a subcutaneous tumor appeared in the same area. It had enlarged gradually over seven months, although she exhibited no obvious symptoms. On preoperative diagnostic imaging, the tumor was mainly found in the skull, extending from the subcutaneous area to the intradural space, and was primarily suspected to be an osteosarcoma. After surgery, the pathological diagnosis was atypical meningioma, and there has been no recurrence for 1 year after the surgery. It is necessary for IM to be considered as a differential diagnosis for skull tumors exhibiting characteristics of osteosarcoma.

Direct double bypass using the posterior auricular artery as initial surgery for moyamoya disease: technical note.

Surgical treatments for moyamoya disease (MMD) include direct revascularization procedures with proven efficacy, for example, superficial temporal artery (STA) to middle cerebral artery (MCA) bypass, STA to anterior cerebral artery bypass, occipital artery (OA) to MCA bypass, or OA to posterior cerebral artery bypass. In cases with poor development of the parietal branch of the STA, the posterior auricular artery (PAA) is often developed and can be used as the bypass donor artery. In this report, the authors describe double direct bypass performed using only the PAA as the donor in the initial surgery for MMD.In the authors' institution, MMD is routinely treated with an STA-MCA double bypass. Some patients, however, have poor STA development, and in these cases the PAA is used as the donor artery. The authors report the use of the PAA in the treatment of 4 MMD patients at their institution from 2013 to 2016. In all 4 cases, a double direct bypass was performed, with transposition of the PAA as the donor artery. Good patency was confirmed in all cases via intraoperative indocyanine green angiography and postoperative MRA or cerebral angiography. The mean blood flow measurement during surgery was 58 ml/min. No patients suffered a stroke after revascularization surgery.

Progressive thrombosis of unruptured aneurysms after coil embolization: analysis of 255 consecutive aneurysms.

INTRODUCTION: We have observed that aneurysms treated by insufficient coil embolization and filled with contrast agent immediately after the procedure are often completely occluded at follow-up. However, there are limited studies showing progressive thrombosis of aneurysms after coil embolization. Herein, we describe our experience with coil embolization for aneurysms, and discuss the factors involved in progressive thrombosis. METHODS: A total of 255 aneurysms treated by coil embolization in our institute between January 2011 and June 2017 and observed >6 months were included. 'Progressive thrombosis' indicated that aneurysms that were neck remnant (NR) or dome filling (DF) immediately after coil embolization changed to complete obliteration (CO) at the 6-month follow-up digital subtraction angiography. The factors involved in progressive thrombosis were assessed. RESULTS: In all aneurysms (n=255), 24 (9.4%) were CO, 82 (32.2%) were NR, and 149 (58.4%) were DF immediately after the procedure. At 6-month digital subtraction angiography, 123 (48.2%) were CO, 95 (37.3%) were NR, and 37 (14.5%) were DF. Retreatment for major recanalization was performed in eight cases (3.1%). One hundred and three aneurysms showed progressive thrombosis. There were significant differences in aneurysm location (P=0.0002), aneurysm dome diameter (P=0.0015), aneurysm neck diameter (P=0.0068), volume embolization ratio (P=0.0054), and endovascular procedure with stent (P=0.0264) between the progressive thrombosis and no thrombosis groups. CONCLUSIONS: Progressive thrombosis can occur in aneurysms after coil embolization depending on aneurysm location and size, and stent use. Thus, the degree of coil embolization and combination with a stent should be adjusted depending on aneurysm type.