Clinical Significance of Carotid Endarterectomy and Carotid Artery Stenting in Older Patients Over 80.

As the average life expectancy increases, neurosurgeons are likely to encounter patients aged 80 years and above with carotid stenosis; however, whether old age affects clinical post-treatment outcomes of carotid endarterectomy (CEA) or carotid artery stenting (CAS) remains inconclusive. Thus, this study aimed to evaluate the outcomes following CEA or CAS in patients aged 80 years and above. This study included older over 80 years (n = 34) and younger patients (<80 years; n = 222) who underwent CEA or CAS between 2012 and 2022. All of them were followed up for a mean of 55 months. All-cause mortality, the incidence of vascular events, ability to perform daily activities, and nursing home admission rates were assessed. During follow-up periods, 34 patients (13.3%) died due to coronary artery disease, malignancy, and pneumonia, and the incidence was significantly higher in the elderly group than in the younger group (P = 0.03; HR, 3.01; 95% CI, 1.53-5.56). The incidence of vascular events did not differ between the older group (29.5%) and the younger group (26.9%, P = 0.58); however, the incidence was significantly higher in patients with high-intensity plaques than in those without that (P = 0.008; HR, 2.83, 95%CI, 1.27-4.87). The decline in the ability to perform daily activities and increased nursing home admission rates were high in elderly patients (P < 0.01). Although the mortality rate was higher in the elderly group, subsequent vascular events were comparable to that in the younger group. The results suggest that CEA and CAS are safe and useful treatments for carotid stenosis in older patients, especially to prevent ipsilateral ischemic stroke.

Anatomy of Intracranial Veins.

The cerebral venous system is complex and sophisticated and serves various major functions toward maintaining brain homeostasis. Cerebral veins contain about 70% of cerebral blood volume, have thin walls, are valveless, and cross seamlessly white matter, ependymal, cisternal, arachnoid, and dural boundaries to eventually drain cerebral blood either into dural sinuses or deep cerebral veins. Although numerous variations in the cerebral venous anatomic arrangement may be encountered, the overall configuration is relatively predictable and landmarks relatively well defined. A reasonable understanding of cerebral vascular embryology is helpful to appreciate normal anatomy and variations that have clinical relevance. Increasing interest in transvascular therapy, particularly transvenous endovascular intervention provides justification for practitioners in the neurosciences to acquire at least a basic understanding of the cerebral venous system.

Predictive Factors of Functional Outcome in World Federation of Neurosurgical Societies Grade V Subarachnoid Hemorrhage.

OBJECTIVE: Patients with World Federation of Neurosurgical Societies (WFNS) grade V subarachnoid hemorrhage (SAH) frequently have poor outcomes. The current understanding of the predictors of functional outcome only in WFNS grade V SAH is limited. METHODS: Patients with WFNS grade V SAH were retrospectively analyzed between April 2008 and August 2019. Surgical treatment is commonly delayed until clinical improvement is observed using a less aggressive approach. Clinical and radiologic data on admission were assessed, and disease-related characteristics were compared between patients with favorable outcomes (modified Rankin Scale score 0-3) and those with unfavorable outcomes (modified Rankin Scale score 4-6). RESULTS: A total of 144 patients were included, and 22 patients (15.3%) achieved favorable outcomes, whereas 122 patients (84.7%) had unfavorable outcomes. Surgical aneurysm repair was performed in all patients with favorable outcomes and in 21.3% of those with unfavorable outcomes. Multivariate analysis showed that Glasgow Coma Scale score of 3, high-grade Early Brain Edema Score, absence of bilaterally light reflex and neurologic improvement, and hypertension were significantly associated with unfavorable outcomes (odds ratio [OR], 9.54, P = 0.03; OR, 5.37, P = 0.04; OR, 11.80, P = 0.009; OR, 0.14, P = 0.02 and OR, 6.53, P = 0.04, respectively). CONCLUSIONS: The final outcome of patients with WFNS grade V SAH was still poor and highly predicted by Glasgow Coma Scale score of 3, high-grade Early Brain Edema Score, absence of bilaterally light reflex and neurologic improvement, and a history of hypertension. The efficacy of aggressive surgical treatment for these patients remains controversial, and the indications should be clearly defined in patients with desolate clinical status on admission.

Management of Dural Arteriovenous Fistulas.

Dural arteriovenous fistula (DAVF) is an acquired lesion. The dural arteries connect with the dural veins within the dura mater in the histopathological study. Sinus type involves the cavernous sinus, transverse-sigmoid sinus, superior sagittal sinus, and anterior condylar confluence (or condylar canal). Non-sinus type involves the anterior cranial base, falcotentorial region, craniocervical junction, convexity, and spinal dura mater.Radical treatment is to obliterate the draining veins in any treatment modalities including endovascular treatment or surgical treatment. Radiosurgery is the last choice. Transvenous embolization plays a main role in the DAVF of the cavernous sinus and anterior condylar confluence. Transarterial embolization with Onyx has dramatically improved the obliteration rate of the transverse-sigmoid, superior sagittal sinuses, and other non-sinus lesions. Transarterial NBCA injection is still the gold standard in the endovascular treatment of the spinal dural and epidural AVFs. Understanding of the functional microvascular anatomy is mandatory, especially in the transarterial liquid injection (Onyx and NBCA). Surgical treatment in the DAVF of the anterior cranial base, craniocervical junction, tentorial region, and spine is a safe and radical treatment. Postoperative follow-up is necessary from the viewpoint of chronological and spacial multi-occurrence of this disease.

Impact of Perihematomal Edema on Infectious Complications after Spontaneous Intracerebral Hemorrhage.

OBJECTIVE: Intracerebral hematoma involves two mechanisms leading to brain injury: the mechanical disruption of adjacent brain tissue by the hematoma and delayed neurological injury. Delayed neurological injury involves perihematomal edema (PHE) formation. Infectious complications following intracerebral hemorrhage (ICH) are a significant contributor to post-ICH recovery. We sought to identify a correlation between PHE volumes and infectious complications following ICH. We also sought to explore the clinical impact of this association. MATERIALS AND METHODS: This retrospective study included 143 patients with spontaneous ICH. CT scans were performed on admission, and 3 h, 24 h, and 72 h following admission. Hematoma and PHE volumes were calculated using a semi-automatic method. The absolute PHE volume at each time point and changes in PHE volume (ΔPHE) were calculated. Neutrophil to lymphocyte ratio (NLR) and serum C-reactive protein (CRP) levels were measured from the obtained blood samples. Neurological deterioration (ND) was assessed in all patients. RESULTS: Infectious complications were associated with ΔPHE72-24 (P < 0.01), whereas there was no association between infectious complications and ΔPHE24-3 (P = 0.09) or ΔPHE3-ad (P = 0.81). There was a positive correlation between ΔPHE72-24 and NLR (r = 0.85, 95% CI: 0.79-0.90, P < 0.01) and between ΔPHE72-24 and CRP levels (r = 0.89, 95% CI: 0.84-0.92, P < 0.01). The ND rate in the group of patients with infectious complications comorbid with high ΔPHE72-24 was higher than the other patient groups (P < 0.01). CONCLUSIONS: This study revealed a correlation between ΔPHE72-24 and infectious complications after spontaneous ICH, which was associated with markers of systemic inflammation. This phenotype linkage is a negative cascade that drives ND.

Complications of Endovascular Treatment of Intracranial Dural Arteriovenous Fistulas.

AIMS: To report the endovascular treatment and complications of intracranial and spinal dural arteriovenous (AV) fistulas. METHODS: A retrospective analysis of 863 cases with dural AV fistulas was completed in the nationwide registry study of the Japanese Society of Neuroendovascular Therapy. RESULTS: Treatments included transarterial/transvenous embolization (TAE/TVE), open surgery, stereotactic radiation, and their combinations. Modified Rankin Scale 0 (mRS-0) of the patients before and after treatment were 21% and 68%, and mRS 0-1were 69% and 86%, respectively. Mortality rate after treatment was 0.6%. Major complications of TAE and TVE were cranial nerve palsy and cerebral infarction. CONCLUSIONS: Major complications resulted from occlusion of vasa nervosum and material migration via dangerous intracranial and extracranial arterial anastomosis.

Ameliorative Effects of Combined Revascularization Surgery on Abnormal Collateral Channels in Moyamoya Disease.

OBJECT: Abnormal collateral channels, so-called moyamoya vessels, play a critical role to compensate cerebral ischemia, but carry the risk for hemorrhagic stroke in moyamoya disease (MMD). The present study was aimed to clarify if superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephalo-myo-duro-arterio-pericranial synangiosis (EDMAPS) can efficiently regress the abnormal collateral channels in MMD patients. METHODS: This study included 92 hemispheres of 61 MMD patients who underwent STA-MCA anastomosis combined with EDMAPS between 2013 and 2019. There were 17 children and 44 adults. We retrospectively analyzed the findings on cerebral angiography before and 3 to 6 months after surgery, including Suzuki's angiographical stage, the development of surgical collaterals, and the extent of abnormal collateral channels such as lenticulostriate, thalamic, and choroidal channels. RESULTS: Following surgery, no pediatric and adult patients experienced any stroke during follow-up periods (40.2±25.5 and 54.9±19.7 months, respectively). Suzuki's stage significantly advanced in both adult and pediatric patients after surgery (P=0.042 and P<0.001). In adult patients, all of the lenticulostriate, thalamic, and choroidal channels significantly regressed after surgery (P<0.001, P=0.012, and P=0.004, respectively). In pediatric patients, however, lenticulostriate and choroidal channels significantly regressed (P=0.005 and P=0.034, respectively). Correlation analysis revealed that the development of surgical collaterals determined the postoperative regression of choroidal channels (P<0.001). CONCLUSION: STA-MCA anastomosis and EDMAPS may be one of the most effective procedures to widely provide surgical collaterals to the operated hemispheres and prevent not only ischemic but also hemorrhagic stroke by regressing the hemorrhage-prone abnormal collateral channels in MMD.

Dilated microvessel with endothelial cell proliferation involves intraplaque hemorrhage in unstable carotid plaque.

BACKGROUND: The purpose of the present study was to clarify the characteristics of endothelial cell (EC) proliferation in intraplaque microvessels in vulnerable plaques and impact on clinical results. METHODS: The present study included 76 patients who underwent carotid endarterectomy. Patients were classified into three groups based on their symptoms: asymptomatic, symptomatic without recurrent ischemic event, and symptomatic with recurrent ischemic event. MR plaque imaging was performed and surgical specimens underwent immunohistochemical analysis. The number of CD31+ microvessels, and Ki67+ and CD105+ ECs in the carotid plaques was quantified, as measurements of maximum CD31+ microvessel diameter. RESULTS: MR plaque imaging yielded 41 subjects (54.0%) diagnosed with plaque with intraplaque hemorrhage (IPH), 14 subjects (18.4%) diagnosed with fibrous plaques, and 21 (27.6%) subjects diagnosed with lipid-rich plaques. The average largest diameter of microvessel in fibrous plaques, lipid-rich plaques, and plaque with IPH was 12.7 ± 4.1 µm, 31.3 ± 9.3 µm, and 56.4 ± 10.0 µm, respectively (p < 0.01). Dilated microvessels (>40 µm) were observed in 9.6% of plaques with IPH but only in 2.8% of lipid-rich plaques and 0% of fibrous plaques (p < 0.01). Ki67+/CD31+ ECs were identified in 2.8 ± 1.2% of fibrous plaques, 9.6 ± 6.9% of lipid-rich plaques, and in 19.5 ± 5.9% of plaques with IPH (p < 0.01). The average largest diameter of microvessels in the asymptomatic group was 17.1 ± 8.7 µm, 32.3 ± 10.8 µm in the symptomatic without recurrence group, and 55.2 ± 13.2 µm in the symptomatic with recurrence group (p < 0.01). CONCLUSION: Dilated microvessels with proliferative ECs may play a key role in IPH pathogenesis. Furthermore, dilated microvessels are likely related to clinical onset and the recurrence of ischemic events. The purpose of the present study was to clarify the characteristics of EC proliferation in intraplaque microvessels in vulnerable plaques and their impact on clinical results, focusing on dilated intraplaque microvessels.

Clinical trial of carotid artery stenting using dual-layer CASPER stent for carotid endarterectomy in patients at high and normal risk in the Japanese population.

BACKGROUND: The dual-layer nitinol CASPER stent was designed to prevent plaque prolapse into its strut and periprocedural stroke. OBJECTIVE: To conduct a clinical trial for government approval of the device in patients at either high or normal risk for carotid endarterectomy (CEA). METHODS: Eligible patients had ≥50% symptomatic stenosis or ≥80% asymptomatic stenosis according to the North American Symptomatic Carotid Endarterectomy Trial methods (peak systolic velocity 130 and 230 cm/s on ultrasonography, respectively). The primary endpoint was the lack of major adverse events (MAEs), defined as death, stroke, and myocardial infarction within 30 days, and ipsilateral stroke within 1 year. The performance goal was set at 90.5%. MAE rates were also compared between the CEA high- and normal-risk groups. RESULTS: 140 carotid artery stenting procedures, including 40% of patients at high risk and 60% at normal risk for CEA, were performed in 13 institutes. MAEs occurred in two cases (one intraprocedural and one postprocedural stroke), and the MAE rate was 1.4%. The non-MAE rate was 98.6% according to Kaplan-Meier analysis, which was superior to the previously set performance goal. The deployment success, target lesion revascularization (TLR), in-stent restenosis, and cerebrovascular event rates were 99.3%, 2.4%, 8.5%, and 7.2%, respectively. The MAE rate in patients with normal CEA risk was 1.2%, which was similar to the high-risk CEA group, with no significant difference due to the small number of MAEs. CONCLUSIONS: The MAE rate following use of the CASPER stent was low (1.4%). The MAE, deployment success, TLR, in-stenosis, and cerebrovascular event rates were similar to those of previous reports.

Clinical and Radiological Features of Childhood Onset Adult Moyamoya Disease: Implication for Hemorrhagic Stroke.

Some of the pediatric moyamoya patients spend their childhood without diagnosed as moyamoya disease (MMD) because of their mild ischemic attacks and emerge again with ischemic or hemorrhagic stroke in their adulthood. This study was aimed to clarify the clinical characteristics of adult moyamoya patients with childhood onset and elucidate the impact of long disease period on their clinical features. Present study included 116 untreated hemispheres of 69 adult patients with MMD. They were divided into two groups: childhood onset group (26 hemispheres of 14 patients) and adult onset group (90 hemispheres of 55 patients). Clinical features were compared between the two groups. The incidence of hemorrhagic stroke was significantly higher in childhood onset group (P = 0.0091). Lenticulostriate and choroidal channels were more developed in childhood onset group (P = 0.044 and P <0.001, respectively). Vault moyamoya was more frequently observed in childhood onset group (P <0.001). The development of surgical collaterals through indirect bypass was more marked in childhood onset group (P = 0.0019). Multivariate analysis revealed that childhood onset and developed choroidal channels were significantly associated with the occurrence of hemorrhagic stroke (OR 4.31 [95% CI 1.21-15.4], P = 0.025 and OR 6.78 [95% CI 1.78-25.8], P = 0.0050, respectively). This study clearly shows that adult moyamoya patients with childhood onset have more developed spontaneous collaterals, which may, in turn, highly causes hemorrhagic stroke. Adult moyamoya patients with "childhood onset" should be recognized as a novel and important concept when elucidating the underlying mechanisms of hemorrhagic stroke in MMD.

High-intensity vessel sign on fluid-attenuated inversion recovery imaging: a novel imaging marker of high-risk carotid stenosis-a MRI and SPECT study.

BACKGROUND: Measurement of luminal stenosis and determination of plaque instability using MR plaque imaging are effective strategies for evaluating high-risk carotid stenosis. Nevertheless, new methods are required to identify patients with carotid stenosis at risk of future stroke. We aimed to clarify the mechanisms and clinical implications of the hyperintense vessel sign (HVS) as a marker of high-risk carotid stenosis. METHODS: We included 148 patients who underwent carotid stent (CAS) or carotid endarterectomy (CEA). MRI FLAIR was performed to detect HVS prior to and within 7 days after CAS/CEA. MR plaque imaging and 123I-iodoamphetamine SPECT was performed prior to CEA/CAS. Detailed characteristics of HVS were categorized in terms of symptomatic status, hemodynamic state, plaque composition, and HVS on time series. RESULTS: Forty-six of 80 symptomatic hemispheres (57.5%) and 5 of 68 asymptomatic hemispheres (7.4%) presented HVS (P < 0.01). Of the 46 symptomatic hemispheres with HVS, 19 (41.3%) presented with hemodynamic impairment and 27 (58.7%) presented without hemodynamic impairment. Of 19 hemispheres with hemodynamic impairment, 12 subjects (63.2%) showed high intensity and 7 (36.8%) showed iso-intensity plaques on T1WI. All 27 hemispheres without hemodynamic impairment showed high-intensity plaques. Of the five asymptomatic and HVS-positive hemispheres, one showed hemodynamic impairment; MR plaque imaging revealed T1 iso-intensity. The other four hemispheres that did not show hemodynamic impairment showed T1WI high-intensity plaques. CONCLUSION: There are two possible mechanisms of HVS, hemodynamic impairment due to severe carotid stenosis and micro-embolism from unstable plaques. HVS could be a radiological marker for high-risk carotid stenosis.

Late (5-20 years) outcomes after STA-MCA anastomosis and encephalo-duro-myo-arterio-pericranial synangiosis in patients with moyamoya disease.

OBJECTIVE: Surgical revascularization is known to reduce the incidence of further ischemic and hemorrhagic events in patients with moyamoya disease, but the majority of previous studies report only short-term (< 5 years) outcomes. Therefore, in this study the authors aimed to evaluate late (5-20 years) outcomes of moyamoya patients after superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and indirect bypass (encephalo-duro-myo-arterio-pericranial synangiosis [EDMAPS]). METHODS: Cumulative incidences of late morbidity/mortality and disease progression were evaluated among 93 patients who underwent STA-MCA anastomosis and EDMAPS. All of the patients were prospectively followed up for longer than 5 years postsurgery (10.5 ± 4.4 years). There were 35 pediatric and 58 adult patients. Initial presentation included transient ischemic attack/ischemic stroke in 80 patients and hemorrhagic stroke in 10 patients, and 3 patients were asymptomatic. Surgery was performed in a total of 141 hemispheres. Follow-up MRI/MRA was performed within a 6- or 12-month interval during the follow-up periods. RESULTS: During the follow-up periods, 92/93 patients were free from any stroke or death, but 1 patient had a recurrence of hemorrhagic stroke (0.10% per patient-year). Disease progression occurred in the territory of the contralateral carotid or posterior cerebral artery (PCA) in 19 hemispheres of 15 patients (1.5% per patient-year). The interval between initial surgery and disease progression varied widely, from 0.5 to 15 years. Repeat bypass surgery for the anterior and posterior circulation resolved ischemic attacks in all 10 patients. CONCLUSIONS: The study results indicate that STA-MCA anastomosis and EDMAPS would be the best choice to prevent further ischemic and hemorrhagic stroke for longer than 10 years on the basis of the demonstrated widespread improvement in cerebral hemodynamics in both the MCA and ACA territories in the study patients. However, after 10 years postsurgery regular follow-up is essential to detect disease progression in the territory of the contralateral carotid artery and PCA and prevent late cerebrovascular events.

Unstable Carotid Plaque as a Phenotype of Chronic Systemic Inflammation Enhances Renal Insufficiency.

PURPOSE: Chronic systemic inflammation is prevalent in patients with chronic kidney disease (CKD) and is linked to the development of cerebrovascular disease. In this study, we explored the association between the unstable plaques and preoperative CKD in patients who underwent carotid endarterectomy (CEA)/carotid artery stenting (CAS). Furthermore, this study also aimed to explore whether there is a difference in the aggravation of renal function with the presence of stable or unstable plaques. PATIENTS AND METHODS: The study included 90 patients who underwent CEA/CAS for carotid artery stenosis. Multivariate analysis was performed to determine the risk factors for CKD. Kaplan-Meier estimation was employed to evaluate the aggravation of renal function following CEA/CAS. RESULTS: Multivariate analysis revealed that contralateral carotid occlusive disease (odds ratio [OR], 4.45; 95% confidence interval [CI], 1.36-14.6), and T1 high-intensity carotid plaque (OR, 3.26; 95% CI, 1.2-8.86) were independent factors of CKD. Kaplan-Meier estimation demonstrated a higher aggravation of renal function in the T1 high-intensity group compared to those in the iso-intensity (P =.03). Following CEA/CAS, the time until aggravation of renal insufficiency was 12.0 ± 9.4 months in the T1 high-intensity group and 24.5 ± 9.6 months in the iso-intensity group (P =.03). CONCLUSIONS: This study demonstrated that contralateral carotid artery stenosis and T1 high-intensity plaques are more frequently observed in patients with CKD. T1 high-intensity carotid plaque is well linked to CKD development in future.

Morbidity and Mortality Conference Can Reduce Avoidable Morbidity in Neurosurgery: Its Educational Effect on Residents and Surgical Safety Outcomes.

BACKGROUND: Morbidity and mortality conferences (MMCs) are now widely implemented in clinical hospitals, but their impact on the education for neurosurgeons remains limited. This prospective study was aimed to assess the efficacy and benefit of MMCs on the education for neurosurgeon. METHODS: All morbidity and mortality events were prospectively recorded and were categorized on the basis of 2 viewpoints. First, they were classified into "avoidable" and "unavoidable" events, based on the quality of each event. Simultaneously, they were classified into 3 groups, including the residents, attendant members, or unclassifiable, based on the experience of the neurosurgeon who were most closely related to each event. The information was compared between early (2013-2014) and late (2015-2017) study periods to evaluate the education value of MMCs. RESULTS: During a 5-year study period, 44 mortality (2.1% per patient) and 201 morbidity events (9.7% per patient) were recorded. There were no significant differences in the incidence of mortality between 2 periods (P = 0.52). The incidence of morbidity significantly decreased from 11.5% (83/723) to 8.4% (118/1403; P < 0.04). Of these, "avoidable" events, but not "unavoidable" events significantly decreased from 7.5% (54/723) to 4.2% (59/1403; P = 0.001). The decrease in the incidence of "avoidable" morbidity was more pronounced in the residents than in the attendant members (P = 0.007 and P = 0.04, respectively). CONCLUSIONS: Knowledge acquisition from MMCs can significantly reduce "avoidable" morbidity events in both residents and experienced neurosurgeons. The educational effect was more distinct in the residents.

Using postoperative remodeling of donor arteries on MR angiography to predict the development of surgical collaterals in moyamoya disease.

OBJECTIVE: The calibers of donor arteries can change dynamically after bypass surgery in patients with moyamoya disease (MMD). The present study aimed to evaluate the cutoffs of caliber changes in donor arteries associated with good surgical revascularization and to assess the impact of clinical factors potentially related to bypass development. METHODS: The authors studied 71 hemispheres of 30 adults and 16 children with MMD who underwent combined direct and indirect revascularization. They quantitatively measured the calibers of the superficial temporal artery (STA), deep temporal artery (DTA), and middle meningeal artery (MMA) with MR angiography (MRA) source images and calculated the postoperative caliber change ratios (CCRs) to assess direct and indirect bypass development. These values were compared with the findings of digital subtraction angiography, in which revascularization areas were categorized into 3 groups (poor, good, and excellent). RESULTS: In both adult and pediatric hemispheres, the median STA and DTA CCRs were higher in better-revascularization groups (p < 0.05), while MMA CCRs were not significantly different among the groups. Receiver operating characteristic analysis revealed that the cutoff STA CCRs of > 1.1 and > 1.3 were associated with good direct revascularization in adult and pediatric hemispheres, respectively. Cutoff DTA CCRs of > 1.6 and > 1.2 were associated with good indirect revascularization in adult and pediatric hemispheres, respectively. Considering these cutoff values, STA and DTA CCRs showed high median values, irrespective of age, severity of cerebrovascular reserve, disease stage, and disease-onset type. CONCLUSIONS: Caliber changes in STAs and DTAs can be easily measured using MRA, and they could be indicators of direct and indirect bypass development. The dual development of a direct and indirect bypass was most frequently observed in the context of a combined bypass procedure in both adults and children with MMD.

Results of 1940 embolizations for dural arteriovenous fistulas: Japanese Registry of Neuroendovascular Therapy (JR-NET3).

OBJECTIVE: Embolization is the most common treatment for dural arteriovenous fistulas (dAVFs). A retrospective, multicenter observational study was conducted in Japan to clarify the nature, frequency, and risk factors for complications of dAVF embolization. METHODS: Patient data were derived from the Japanese Registry of Neuroendovascular Therapy 3 (JR-NET3). A total of 40,169 procedures were registered in JR-NET3, including 2121 procedures (5.28%) in which dAVFs were treated with embolization. After data extraction, the authors analyzed complication details and risk factors in 1940 procedures performed in 1458 patients with cranial dAVFs treated with successful or attempted embolization. RESULTS: Transarterial embolization (TAE) alone was performed in 858 cases (44%), and transvenous embolization (TVE) alone was performed in 910 cases (47%). Both TAE and TVE were performed in one session in 172 cases (9%). Complications occurred in 149 cases (7.7%). Thirty-day morbidity and mortality occurred in 55 cases (2.8%) and 16 cases (0.8%), respectively. Non-sinus-type locations, radical embolization as the strategy, procedure done at a hospital that performed dAVF embolization in fewer than 10 cases during the study period, and emergency procedures were independent risk factors for overall complications. CONCLUSIONS: Complication rates of dAVF embolization in Japan were acceptable. For better results, the risk factors identified in this study should be considered in treatment decisions.

Strategy and effect of repeat bypass surgery for anterior/posterior circulation in refractory moyamoya disease.

OBJECTIVE: In this study the authors aimed to describe clinical features, surgical techniques, and long-term outcomes of repeat bypass surgery required for a certain subset of patients with moyamoya disease. METHODS: The authors retrospectively reviewed a total of 22 repeat bypass surgeries for 20 patients (age range 1-69 years) performed during the last 20 years at their institutions. The patients were classified into 2 groups. Group A included 10 patients who underwent repeat bypass surgery for anterior circulation due to insufficient revascularization on the ipsilateral side. Group B included 10 patients who underwent repeat bypass surgery for posterior circulation due to the involvement of the posterior cerebral artery (PCA) after successful initial surgery for anterior circulation. RESULTS: Preoperative symptoms included headache in 3 patients, transient ischemic attack in 10, cerebral infarction in 3, and intracranial hemorrhage in 4 patients. Intervals between the initial bypass surgery and repeat bypass surgery were 0.3-30 years (median 3 years). In group A, superficial temporal artery to middle cerebral artery (MCA) anastomosis and indirect bypass were performed on 7 hemispheres. Only indirect bypass was performed on 3 hemispheres because of the lack of suitable donor or recipient arteries. In group B, occipital artery (OA) to PCA anastomosis and indirect bypass were conducted on 4 hemispheres, and OA-MCA anastomosis and indirect bypass on 1 hemisphere. Only indirect bypass was conducted on 7 hemispheres because of the lack of suitable recipient arteries. All 22 repeat bypass surgeries were successfully conducted. During follow-up periods (median 4 years), none of the patients suffered repeat stroke except 1 patient who died of recurrent intracerebral hemorrhage 3 years after repeat bypass surgery for anterior circulation. CONCLUSIONS: Repeat bypass surgery was feasible and effective to reduce further incidence of headache attack, transient ischemic attack, and ischemic/hemorrhagic stroke in moyamoya disease patients. Through precise radiological analysis, surgical procedures should be planned to yield maximal therapeutic effects.

Stenosis Severity-Dependent Shrinkage of Posterior Cerebral Artery in Moyamoya Disease.

OBJECTIVE: The involved carotid forks in moyamoya disease (MMD) will show decreases in both luminal caliber and outer diameter. The present study aimed to clarify the changes in the outer diameter associated with luminal stenosis/occlusion of the posterior cerebral artery (PCA) in patients with MMD. METHODS: The present study included 24 pediatric and 48 adult patients with MMD and 17 healthy adult controls. Using magnetic resonance angiography, the degree of PCA involvement was classified into 3 grades: grade 0, normal; grade 1, stenotic; and grade 2, occluded. Using 3-dimensional constructive interference in steady state, the outer diameters were quantified in the P2 segment. All the patients were followed up to identify the disease progression in the PCA. RESULTS: The outer diameter of the P2 segment significantly decreased in a stepwise fashion in parallel with the severity of the luminal stenosis. In pediatric patients, the outer diameters of the P2 segments were 2.0 ± 0.26 mm, 1.5 ± 0.42 mm, and 0.87 ± 0.15 mm in those with grade 0, 1, and 2, respectively (P < 0.001). In adult patients, the outer diameters of the P2 segments were 2.0 ± 0.34 mm, 1.5 ± 0.34 mm, and 1.1 ± 0.17 mm in those with grade 0, 1, and 2, respectively (P < 0.001). We found no significant difference between grade 0 PCA of the adult patients and the PCA of the healthy controls (P = 0.92). Disease progression led to further arterial shrinkage of the P2 segment (n = 4). CONCLUSIONS: The results of our study have shown that the involved PCA demonstrates, not only luminal stenosis, but also arterial shrinkage in MMD. This finding strongly suggests that the underlying mechanism in the development of MMD is common in both the carotid fork and PCA.

Impact of Interethnic Difference of Collateral Angioarchitectures on Prevalence of Hemorrhagic Stroke in Moyamoya Disease.

BACKGROUND: Fragile, dilated moyamoya vessels are the main source of hemorrhagic stroke in moyamoya disease (MMD). However, the prevalence of hemorrhagic stroke largely differs between Asian and western countries, although the underlying pathophysiology has not been clarified. OBJECTIVE: To systematically analyze the difference of collateral angioarchitectures between Japanese and European Caucasians with MMD. METHODS: This study included 71 patients with MMD, including Japanese (n = 41) and European Caucasians (n = 30). Using preoperative cerebral angiography, the developments of lenticulostriate artery (LSA), anterior choroidal artery (AChoA), posterior communicating artery (PcomA), and posterior choroidal artery (PChoA) were precisely evaluated, and ethic difference was analyzed in terms of patients' age and the onset type. RESULTS: Cerebral angiography demonstrated that the marked dilatation of AChoA and PChoA were significantly more remarkable in Japanese than in European Caucasians (P = .004 and P = .002, respectively). Ageing advanced the dilatation and extension of PChoA and PcomA, and diminished the development of LSA in Japanese patients (P < .001, P = .03, and P = .03, respectively). European Caucasian patients did not have the specific dilated pattern like Japanese patients. CONCLUSION: The marked dilatation of PChoA and PcomA is considered a powerful predictive marker of hemorrhage in MMD. Collateral channels spontaneously shift from the anterior to posterior circulation in Japanese patients during ageing but not in European Caucasian patients. These different dilation patterns of the collateral pathway may be associated with an ethnic difference of the clinical onset type in MMD.

Efficacy of Carotid Endarterectomy for Mild (<50%) Symptomatic Carotid Stenosis with Unstable Plaque.

BACKGROUND: Carotid endarterectomy (CEA) is known to reduce stroke risk in patients with symptomatic, moderate to severe carotid stenosis but has no apparent impact in patients with symptomatic, mild (less than 50%) carotid stenosis. However, recent development of noninvasive imaging modalities has shown that a certain subgroup of patients are at high risk for further ischemic events despite antiplatelet therapy. This study, therefore, aimed to clarify the patients' clinical features and explore the impact of CEA for them. METHODS: This prospective cohort study included 74 patients who underwent CEA for symptomatic carotid stenosis between April 2012 and December 2016. Of these, 16 (22%) had mild (less than 50%) carotid stenosis. Their demographic, radiologic, intraoperative, and pathologic findings were precisely analyzed, and their outcome after CEA was examined for 38.5 ± 13.3 months. RESULTS: Of these 16 patients, 12 had already been treated with antiplatelets against previous ischemic cerebrovascular or coronary artery diseases. Plaque magnetic resonance imaging revealed that all patients had vulnerable plaque, including lipid-rich plaque (n = 6) and intraplaque hemorrhage (n = 10). Intraoperative observations confirmed this. Histologic analysis revealed that inflammatory cells and fragile angiogenesis were widely found in the specimens. Only 1 patient experienced transient (less than 30 days) neurologic deficit after CEA, and none of them repeated cerebrovascular events during the follow-up period. CONCLUSIONS: It is not rare the patients who are at high risk for subsequent ischemic events because of vulnerable plaque despite mild (less than 50%) carotid stenosis. Magnetic resonance imaging is quite useful to noninvasively detect such vulnerable plaque. CEA is a promising procedure to treat these patients.