Newly Developed Aneurysm at the Anastomosis Site of a Superficial Temporal Artery to Middle Cerebral Artery Bypass Successfully Treated by Endovascular Embolization.

BACKGROUND: The superficial temporal artery (STA) to middle cerebral artery (MCA) bypass is an effective treatment procedure for steno-occlusive severe ischemic disease of the anterior circulation. The formation of an aneurysm at the anastomosis site is a rare complication, and the mechanism underlying this condition and the appropriate treatment strategy, have not yet been established. We describe a case of an unruptured anastomosis aneurysm that was treated by endovascular embolization 7 years after bypass surgery. CASE DESCRIPTION: A 62-year-old woman presented with slurred speech, with magnetic resonance imaging and angiography showing multiple infarctions in her left cerebral hemisphere and severe stenosis in the left internal carotid artery and left MCA. An STA-MCA anastomosis was performed without neurologic sequelae. Five years later, follow-up magnetic resonance imaging showed that an aneurysm had formed at the MCA side of the anastomosis site. After 2 years, the saccular aneurysm had grown and was embedded in the brain parenchyma. Because the patient had experienced repeated problems with surgical wound healing, an endovascular intervention was performed, achieving obliteration of the aneurysm by coil embolization. CONCLUSIONS: Endovascular treatment is a feasible and efficacious treatment option for an aneurysm at the anastomosis site of an STA-MCA bypass.

[Tentorial Dural Arteriovenous Fistula with Bithalamic Lesions and Bilateral Basal Ganglia Hemorrhage:A Case Report].

OBJECTIVE: We report an unusual case of tentorial dural arteriovenous fistula(DAVF)with bithalamic lesions and bilateral intracranial hemorrhage. CASE PRESENTATION: A 73-year-old man presented with lethargy and progressive cognitive decline. Imaging demonstrated bithalamic edematous lesions and bilateral basal ganglia hemorrhage in the right putamen and left internal capsule. Angiography revealed tentorial DAVF fed by both the internal and external carotid arteries. A shunted pouch was present in the superior petrosal sinus, and retrograde reflux drainage was see in the deep venous system, including the basal vein, vein of Galen, and internal cerebral veins with congestion. Initially, transarterial embolization was palliatively performed, and subsequently, a microsurgery achieved obliteration of the tentorial DAVF. Postoperatively, the bilateral thalamic changes disappeared, although sequela of the intracranial hemorrhage persisted. CONCLUSION: Deep venous congestion due to tentorial DAVF induced unusual bithalamic lesions and bilateral basal ganglia hemorrhage. Tentorial DAVF was treated with combined endovascular and surgical operations. Tentorial AVF is an aggressive vascular disease, and prompt diagnosis and treatment are necessary.

[Current Status of Thrombectomy Calls for Acute Ischemic Stroke for a Single Neurointerventionist in a Regional Hospital].

OBJECTIVE: The purpose of this study was to investigate the current status of thrombectomy calls for acute ischemic stroke for a single neurointerventionist in a regional hospital. METHODS: We retrospectively evaluated patients with thrombectomy calls for a neurointerventionist from January to November 2016 in our hospital, where a single board-certified neurointerventionist conducts endovascular interventions. Number, frequency, and time of thrombectomy calls were analyzed. Patients ineligible for revascularization were still used in analysis even though the neurointerventionist did not perform thrombectomy. RESULTS: Over 11 months(334 days), there were 105 calls, of which 48 were during duty hours and 57 during off-duty hours. The neurointerventionist was called once every 3.2 days in total, once every 4.7 days during duty hours, once every 5.7 days during off-duty hours of working days, and once every 6.2 days during holidays. Thrombectomies were performed in 37 cases(35%). Thrombectomies were performed once every 9.1 days and once every 2.8 calls. Twenty-four patients presented with ischemic stroke with large vessel occlusion, but they were determined to be ineligible for thrombectomy because of progressed ischemia in 7 patients, poor clinical condition in 7, or symptom recovery or recanalization in 10. Diagnoses of 42 patients who were not indicated for thrombectomy included ischemic stroke without major artery occlusion in 24 patients and intracerebral hemorrhage in 14. CONCLUSION: In a regional hospital with a single neurointerventionist, the frequency of thrombectomy calls was about once in every 3 days, and approximately half of them occurred during off-duty hours. A thrombectomy was performed about once every 9 days and about once every 3 thrombectomy-calls. Measures should be taken to reduce the burden on neurointerventionists in stroke centers, especially in understaffed institutes.

Relationship between low response to clopidogrel and periprocedural ischemic events with coil embolization for intracranial aneurysms.

OBJECTIVES: Low response to antiplatelet drugs is one of the risk factors for ischemic events. We examined the influence of low response to clopidogrel on symptomatic ischemic events and new ischemic MRI lesions with endovascular intracranial aneurysmal coil embolization. MATERIALS AND METHODS: Between August 2010 and July 2013, 189 procedures in 181 consecutive patients who underwent endovascular coiling and received clopidogrel before treatment were investigated retrospectively. Platelet aggregation activity was examined by VerifyNow analysis. Low response to clopidogrel was defined as P2Y12 reaction units ≥230 in this study. Symptomatic ischemic complications within 30 days and postoperative new ischemic lesions on MRI-diffusion weighted imaging were evaluated. RESULTS: 66 of 189 (34.9%) cases were low responders to clopidogrel. Ischemic complications occurred in 2 of 66 (3.0%) low responders compared with 6 of 123 (4.9%) responders (p=0.72). A new high intensity spot larger than 5 mm was significantly more frequent in low responders (26 of 66; 39.4%) than in responders (26 of 121; 21.2%; p=0.01). On multivariate analysis, independent risk factors for larger new ischemic lesions were low response to clopidogrel, smokers, posterior location, and aneurysms with a larger neck. CONCLUSIONS: Low response to clopidogrel had little effect on clinical outcome although it increased asymptomatic large ischemic lesions in this cohort.

Treatment of Symptomatic Bilateral Cavernous Carotid Aneurysms: Long-term Results of 6 Cases.

BACKGROUND: Bilateral cavernous carotid aneurysms (CCAs) are very rare. A treatment strategy for symptomatic bilateral CCAs has not been established because of their complex pathogenesis. Here we report our treatment strategy and long-term results for 6 cases of symptomatic bilateral CCAs. METHODS: From January 2007 to December 2013, we treated 6 patients (2 men and 4 women; mean age at first treatment, 56.0 years) with symptomatic bilateral CCAs. RESULTS: All patients began to experience unilateral symptoms. Five of the 6 underwent high-flow bypass (HFB) with parent artery occlusion (PAO), and 1 received PAO only. Mean follow-up period after the first treatment was 61.3 months. All symptoms improved after the treatment. Five contralateral CCAs became enlarged during the follow-up period. Of these, 4 became symptomatic. One patient received superficial temporal-middle cerebral artery bypass with PAO, 2 received HFB with PAO, and 1 refused treatment. Final modified Rankin Scale scores were 0 in 4 patients, 1 in 1 patient, and 2 in 1 patient. There was no mortality in this series. CONCLUSIONS: HFB with PAO is feasible as the first treatment for symptomatic bilateral CCAs. This treatment strategy steadies and simplifies future treatment of contralateral CCAs should they become symptomatic.

Results and current trends of multimodality treatment for infectious intracranial aneurysms.

The authors retrospectively reviewed their cases of infectious intracranial aneurysms and discuss results and trends of current treatment modalities including medical, neurosurgical, and endovascular. Twenty patients (10 males and 10 females; mean age 46 years) with 23 infectious aneurysms were treated by various treatment modalities during a 15-year period. Fifteen cases (75.0%) were caused by infective endocarditis. Eleven aneurysms (47.8%) were ruptured. Two aneurysms (8.7%) presented a mass effect and 7 (30.4%) were unruptured and asymptomatic. The average aneurysm size was 6.5 ± 4.8 mm (range 1-22 mm). The aneurysms were located in proximal cerebral circulation in 7 (30.4%) and distal in 16 (69.6%). Six (26.1%) aneurysms were treated surgically (5: trapping, 1: neck clipping), 10 (43.5%) endovascularly (7: trapping, 2: proximal occlusion, 1: saccular coiling), and the remaining 7 (30.4%) medically. Endovascular treatment was gradually increased with time. Medical and surgical treatments were continuously performed during the study period. Surgery was preferred for the patient with intraparenchymal hematoma or treated by bypass surgery. Three periprocedural minor complications occurred in endovascular treatment. There was one postoperative infarction with permanent deficit developed from surgical treatment. During the follow-up period (mean 28.8 months), none of the aneurysms presented a recurrence or rebleeding. Thirteen patients (65.0%) had favorable clinical outcomes (modified Rankin Scale: 0-2), although four (20.0%) had poor outcomes (modified Rankin Score: 5-6). A multimodal approach for the management of infectious aneurysms achieved satisfactory results. Endovascular intervention is a feasible and efficacious treatment option and surgical intervention is still an indispensable procedure.

The 'one and a half round microcatheterization technique' for stent-assisted coil embolization of intracranial aneurysm: technical case series.

BACKGROUND: Stent-assisted coil embolization is useful for wide-necked, large and giant aneurysms, and is effective for avoiding coil herniation. However, the mobility of the microcatheter is often restricted, resulting in deviated or unbalanced coiling. In order to prevent this insufficient coiling, the authors devised a method for microcatheterization, the 'one and a half round microcatheterization technique'. This technique is based on the formation of a one and a half round loop by the microcatheter along the aneurysmal wall. Furthermore, this technique can be supplemented with the double-catheter technique. METHODS: From July 2010 to July 2012, the authors used this technique for 20 aneurysms in 20 patients (6 men and 14 women; mean age 61.7 years). The one and a half round microcatheterization technique was used alone in 12 cases and was supplemented with the double-catheter technique in eight. The clinical and angiographic results were retrospectively evaluated. RESULTS: The average aneurysm size was 16.7 mm; 12 aneurysms (60%) were located at the internal carotid artery, 5 (25%) at the basilar artery and 3 (15%) at the vertebral artery. Immediate angiographic results showed complete obliteration in 6 aneurysms (30%) and residual neck in 10 (50%), leaving 4 residual aneurysms (20%). This technique was useful and acceptably safe for packing the aneurysmal sac entirely. During an average follow-up of 20.5 months, 13 of the 18 aneurysms (72%) were stable or had improved, although 3 (16%) required retreatment. CONCLUSIONS: The one and a half round microcatheterization technique provides dense coil packing for stent-assisted embolization of large or giant aneurysms.

[Systematic review of complications for proper informed consent (9) periprocedural complications of carotid artery stenting: a review article].

BACKGROUND: Carotid artery stenting(CAS)is a common procedure for the treatment of high surgical risk patients with carotid artery stenosis. Recent clinical study failed to show the non-inferiority of CAS to carotid endarterectomy(CEA)because of higher complication rates of CAS. However the result of a multicenter case study in Japan with tailored application of adequate devices including stents and protection devices revealed the safety of CAS in Japan. In this article the overall review in the previous reports of CAS are reviewed focusing on the complications and clinical outcome. METHOD: Five randomized controlled trials concerning CAS versus CEA and 14 case series of CAS were reviewed, and the rates of periprocedural complications of CAS including death, stroke, myocardial infarction, hypotension and bradycardia, cranial nerve palsy, major vascular injury, cholesterol crystal embolization and hyperperfusion syndrome were summarized. RESULT: Mortality within 30 days of procedures was 0.9%. The rate of any stroke was 6.0% from the five RCT results, but a recent 14-case series reported any stroke rate at 3-4% and severe stroke rate at 1-2% respectively. The rates of acute myocardial infarction, hypotension, and bradycardia were 1%, 4%, and 4-12% respectively. The rate of bleeding complication of the access root was about 2% and non-bleeding was 1-2%. Cholesterol crystal embolization occurred in 0.2%. Incidence of hyperperfusion syndrome occurred in 1.5%, and intracranial hemorrhage in 0.8%. CONCLUSION: Historically, the rapid improvement of devices and technical skills have contributed to the better clinical results. Also the lessons from complication cases have led to more appropriate indication and perfect protection to avoid adverse events. Therefore the rate of complication is always improving and those written in this article may not reflect the present real number. This article should be quoted with the previous reference as well as the newest data according to the operator's own experiences on taking informed consent.

Pial arteriovenous fistula as a cause of bilateral thalamic hyperintensities--an unusual case report and review of the literature.

INTRODUCTION: Isolated bilateral thalamic congestion due to an arteriovenous malformation (AVM) is a rare entity. Few case reports of dural arteriovenous fistula associated with it have been reported in the literature. The association of pial arteriovenous fistula (pial AVF) with thalamic hyperintensities has never been described before. The pial AVF is a recently recognized lesion in which the multiple pial arterial feeders drain into a single venous channel without a nidus like in conventional AVM. In spite of being congenital in origin, these lesions may have expression in adulthood due to abrupt change in the venous drainage system. Successful management of pial AVF associated with bilateral thalamic hyperintensities is described here with review of the literature. CASE PRESENTATION: A 60-year-old man presented with rapidly progressive gait disturbance and cognitive decline. Magnetic resonance imaging (MRI) showed hyperintensities in the thalami on T2-weighted and fluid attenuated inversion recovery image. Digital subtraction angiography revealed a pial AVF near the splenium of corpus callosum. It had feeders from posterior choroidal arteries and drained into the vein of Galen through an abnormal mesencephalic vein. The stagnation and increase of pressure in the deep venous system led to congestion in the thalami. He was treated by partial transarterial embolization of the feeders followed by gamma knife therapy (GKT). The clinical symptoms and MRI improved rapidly after embolization and further reduction in shunt flow was observed after GKT. CONCLUSION: Strong suspicion of vascular malformation as a cause of bilateral thalamic hyperintensities helps in early detection. Such lesions like pial AVF presented here require active intervention by surgery or endovascular therapy. GKT is an important adjuvant in lesions refractory to either of them.

[Intracardiac migration of a ventriculoatrial shunt catheter treated by endovascular transvenous retrieval].

The authors report a case of intracardiac migration of a ventriculoatrial (VA) shunt catheter and transvenous retrieval of the migrated shunt catheter. A 67-year-old male, who had previously undergone a VA shunt for hydrocephalus after subarachnoid hemorrhage, presented disorientation, memory disturbance and gait disturbance without any cardiopulmonary symptom. Head CT scan revealed ventriculomegaly that indicated hydrocephalus due to shunt malfunction. Radiogram revealed that the caudal segment of the broken atrial catheter had migrated into the heart (right ventricle). The migrated shunt catheter was retrieved by a transfemoral approach with a pigtail catheter and a snare retriever catheter, although the rostral catheter segment partially remained because of tight adhesion. The VA shunt was then reconstructed. Postoperatively, symptoms due to recurrent hydrocephalus were markedly improved and the VA shunt functioned well. Transvenous catheter retrieval was a less invasive and effective method for VA shunt catheter migration.

[Resistance to antiplatelet agents assessed by a point-of-care platelet function test and thromboembolic adverse events in neurointervention].

OBJECTIVE: To clarify the frequency of Japanese patients who are resistant to antiplatelet agents, and then clarify correlations between resistance and thromboembolic adverse events in neurointervention. METHODS: Blood samples were collected from 163 patients who were taking antiplatelet agents and received neurointervention, with 128 samples collected just before neurointervention. Residual platelet function was measured using a point-of-care platelet function test, VerifyNow®, and then the frequency of patients resistant to drugs (low-responders), correlations between resistance and thromboembolic events, and effects of adding cilostazol to clopidogrel administration were analyzed. Cut-off values were defined as 550 Aspirin Reaction Units (ARU), 230 P2Y12 Reaction Units (PRU), and 50%inhibition of P2Y12, respectively. RESULTS: Three of 105 patients (2.9%) taking aspirin at 100 mg/day were low-responders, whereas 48 (41.0%, as measured by PRU) or 80 (68.4%, as measured by %inhibition) of 117 patients taking clopidogrel at 75 mg/day were low-responders. Among the 19 patients taking cilostazol 200 mg/day in addition to clopidogrel 75 mg/day, platelet functions were significantly more strongly inhibited compared to patients taking clopidogrel alone (p=0.02 by PRU, p=0.005 by %inhibition). Thromboembolic adverse events occurred in 7 patients. Among these 7 patients, 6 who were taking aspirin were all responders to aspirin, while 4 of the 6 patients taking clopidogrel were low-responders to clopidogrel. In 69 patients who received aneurysmal transarterial embolization, 2 thromboembolic complications occurred among low-responders (p=0.09). CONCLUSION: Aspirin resistance is rare in Japanese individuals. With aneurysmal transarterial embolization, thromboembolic events tended to occur among clopidogrel low-responders. Addition of cilostazol may offer one method of overcoming clopidogrel resistance.

Magnetic resonance fluid dynamics for intracranial aneurysms--comparison with computed fluid dynamics.

BACKGROUND: Hemodynamics in intracranial aneurysms is thought to play an important role in their growth and rupture. Usual computed fluid dynamics (CFD) based on three-dimensional (3D) computed tomographic (CT) angiography requires a time-consuming process for analysis. Magnetic resonance fluid dynamics (MRFD) based on MR images is a new tool for analyzing flow dynamics and a promising method for obtaining such information more easily. We compared the data from MRFD and CFD and studied the clinical feasibility of MRFD. METHODS: A total of 15 aneurysms, including two ruptured ones, in 15 patients were investigated with MR imaging and 3D-CT angiography. The flow data of MRFD and CFD, 3D stream lines, flow velocity profile and wall shear stress (WSS) were extracted from the image reconstruction and were compared each other. RESULTS: Both flow dynamics images showed quite similar 3D flow pattern and WSS map. However, the calculated value of maximum WSS was quite different and there was no significant correlation. Further, in one ruptured case, CFD showed less visualization to evaluate the intra-aneurysmal flow. Interestingly, one delayed rupture case showed a particular flow pattern with abnormal secondary flow in the bottom of the aneurysm before rupture, which might suggest the specific finding of rupture risk. CONCLUSION: MRFD is a valuable and less invasive tool to evaluate aneurysmal fluid dynamics. It can be obtained from the usual MRI examination without contrast medium and exposure to radiation. Although there is a problem of consistency of the absolute value of WSS between MRFD and conventional CFD, it may be useful to predict the risk of enlargement or rupture of aneurysms based on the information of the similar distribution of WSS and flow patterns. The quantifiable analysis and establishment of a meaningful threshold for high risk should be further studied.

Selective propofol injection into the M1 segment of the middle cerebral artery (MCA Wada test) reduces adverse effects and enhances the reliability of the Wada test for determining speech dominance.

OBJECT: The Wada test is had been the most reliable for determining speech dominance. Drugs injected into the internal carotid artery, however, may be heterogeneously distributed as the result of asymmetry of the anterior cerebral arteries and the presence of a fetal-type posterior cerebral artery. Variations in drug distribution could occasionally alter consciousness and complicate the evaluation of the test results. We examined selective propofol injection into the M1 segment of the middle cerebral artery (MCA Wada test). METHODS: For the MCA Wada test (17 patients), 7 or 8 mg of propofol was injected via a microcatheter navigated into the M1 segment, and language function was evaluated by patient performing several tasks. The conventional Wada test (internal carotid artery [ICA] Wada test) was performed in four patients (both the ICA and MCA Wada tests were performed in one patient). The efficacy and adverse effects of both procedures were evaluated; all tests were performed by well-trained interventional neuroradiologists. RESULTS: Immediately after propofol injection during the MCA Wada test, patients developed transient contralateral hemiplegia and transient aphasia (in the case of injection on the dominant side). Confusion and other severe adverse effects did not occur during the MCA Wada test, but two of four patients who underwent the ICA Wada test showed altered consciousness that affected the performance of the test. CONCLUSIONS: The MCA Wada test is a feasible and reliable preoperative evaluation, if performed by a trained team of interventional neuroradiologists.

[Assessment of mental condition and anxiety in patients receiving neuroendovascular treatment].

OBJECTIVE: Neuroendovascular treatment (NET) is an effective and minimally invasive procedure used for patients with vascular disease of the central nervous system. The purpose of this study was to examine anxiety levels using standardized psychometric tools and an original questionnaire among patients before and after NET. METHOD: A total of 40 patients who underwent NET were included. There were 18 patients with unruptured cerebral aneurysm, 18 with carotid stenosis, and 4 other cases. Patients were asked to complete a State-Trait Anxiety Inventory (STAI) and also to fill out a questionnaire about perioperative anxiety. It elicited the following information: (a) state-anxiety score and level before and after NET; (b) trait-anxiety score and level before and after NET; and (c) perioperative anxiety about NET. In all cases, the procedure was performed under local anesthesia. RESULTS: The preprocedural state-anxiety score was high in many patients (82%). The principal cause of the preprocedural anxiety was the procedure-related complications (92%). Patients with cerebral aneurysm experienced anxiety during the procedure because they could not know which stage of the procedure was involved. Their state-anxiety score was improved in the postprocedural examination (88%). However, patients were still anxious about postoperative complications and recurrence, particularly those with cerebral aneurysm. Patients with cerebral aneurysm generally tended to experience a higher level of anxiety than those with carotid stenosis. CONCLUSION: Though NET is apt to be thought as a relatively easy procedure, patients actually felt much anxiety, especially those with cerebral aneurysm. Due care for perioperative anxiety in patients who undergo NET is important.