Cerebral hyperperfusion syndrome is a rare but devastating complication after carotid endarterectomy (CEA) or carotid artery stenting (CAS). We evaluated whether arterial spin labeling (ASL) can predict cerebral hyperperfusion syndrome after carotid revascularization. Here we reviewed 10 cases of carotid artery stenosis treated with CEA or CAS. Five cases presented with hyperperfusion phenomenon on single photon emission computed tomography. In four of these five cases, ASL was found to be useful in predicting hyperperfusion phenomenon. There were no cases of intracerebral hemorrhage. ASL is noninvasive and useful for understanding cerebral perfusion during the perioperative period that requires several minutes on routine MRI. However, there are some limitations. To avoid misinterpretation of data, it is important that clinicians have a good understanding of the basic principles of ASL.
We provide a novel model of cerebral circulation simulation for predicting the risk of hemodynamic infarction in severe stenosis or occlusion at the internal carotid artery (ICA) origin. This model used the patient-specific multiscale blood flow simulation, which was used to construct the three-dimensional (3D) model obtained from patient's data from time-of-flight magnetic resonance angiography, combined with the 1D and 0D models for peripheral branching arteries. In addition to the morphological information, the inflow and outflow boundary conditions were important for the patient-specific computational flow-dynamic 3D model with the arterial circle of Willis. Inflow volumes at the bilateral ICAs and vertebral arteries (VAs) were quantitatively measured by using phase-contrast magnetic resonance angiography (PC-MRA), whereas outflow volumes at the major intracranial arteries were measured by using iodoamphetamine single-photon emission computed tomography (IMP-SPECT). Each outflow volume (mL/min) on IMP-SPECT was calculated as follows: mean regional cerebral blood flow (mL·min-1·100 g-1 brain tissue) in each newly created vascular territory × voxel volume (voxel number × voxel size) × 1.04 (density of a human brain tissue) / 100, and revised by using the total inflow volume on PC-MRA. We evaluated 11 patients with ≥60% stenosis or occlusion at the unilateral ICA origin. The mean inflow volumes of the ICA and VA in the normal hemispheres were 296 and 153 mL/min, respectively. The mean outflow volumes of the anterior, middle, and posterior cerebral arteries (ACA, MCA, and PCA) in the normal hemispheres were 86,169, and 71 mL/min at rest, and 115,236, and 96 mL/min after the acetazolamide test, respectively. The increasing ratio of each outflow volume, termed cerebrovascular reserve (CVR), was ≥30% in the normal hemispheres. Three of 11 patients (case 5, 73% stenosis; case 8, 98% stenosis; case 11, occlusion) showed decreased CVR <10% of the ACA and/or the MCA at the side of the ICA severe stenosis. The stenosis ratio of the ICA origin was only one cause of the decreased outflow volume or CVR of the ACA or MCA; however, it was directly influenced by the inflow volume of the ICA. This novel multiscale blood flow simulation model is useful for predicting subsequent hemodynamic ischemic attacks.
The purpose of this study is to clarify the therapeutic outcomes for symptomatic lowgrade carotid stenosis with vulnerable plaque. We investigated 43 patients with symptomatic lowgrade stenosis (<50%) and a high-signal plaque on T1-weighted imaging. Single antiplatelet therapy (APT) was started, and recurrent ischemic events were treated with dual APT. Carotid endarterectomy (CEA) was considered when recurrence occurred refractory to dual APT. During follow-up (mean, 28.1 ± 23.5 months), 23 of 43 patients (53%) experienced recurrent events. Fifteen of the 26 patients who underwent dual APT had recurrent events. Fourteen patients were treated with CEA, and the complication seen was temporary hoarseness. During postoperative follow-up (mean, 24.8 ± 17.6 months), no patients showed ipsilateral ischemic events. We concluded that symptomatic low-grade carotid stenosis with a high-signal plaque on carotid magnetic resonance imaging tends to be associated with a high risk of recurrent ischemic events, even with dual APT. CEA for symptomatic lowgrade carotid stenosis might be safe and effective.
The operative indication for pseudo-occlusion of the internal carotid artery is controversial. In this study, we report the technical aspects of and periprocedural care in carotid artery stenting (CAS) for the treatment of this condition. Nineteen cases of pseudo-occlusion of the internal carotid artery (17 symptomatic, 2 asymptomatic) were treated with stenting. Acetazolamide-enhanced singlephoton emission computed tomography revealed hemodynamic compromise in 14 of the 19 cases. To prevent postoperative hyperperfusion syndrome, staged angioplasty and stenting were performed in seven cases. All cases were treated with a flow reversal embolic protection technique during the initial treatment. We observed postoperative intracerebral hemorrhage in one patient due to postoperative hyperperfusion syndrome. Thereafter, we used dexmedetomidine (DEX), a selective α-adrenergic agent, as an intra- and postoperative sedative and analgesic agent, in nine cases to stabilize intraoperative hemodynamics. After staged percutaneous transluminal angioplasty and periprocedural use of DEX, we did not observe hyperperfusion syndrome after CAS. In five cases with extremely tight lesions, we experienced difficulties in crossing the guidewire. In such cases, we applied a 0.014-in coronary chronic total occlusion guidewire to cross the lesions. In this study, we demonstrated fairly positive outcomes of CAS in patients with pseudo-occlusion of the internal carotid artery. This was achieved by focusing on the prevention of hyperperfusion syndrome and proper management of perioperative procedures, especially with respect to blood pressure control.
UCAS Japan was conducted to clarify the natural course of unruptured cerebral aneurysms. Method: According to a pre-specified protocol, 5, 720 patients with 6, 697 aneurysms were prospectively registered and rupture risks were analyzed. Results: During 11, 660 aneurysm-years of follow-up, 111 aneurysms ruptured. The total annual rupture rate was 0.95%. A multivariate Cox regression model showed that size, location, and shape (association with bleb formation) were significantly associated with rupture. UCAS data were included in the meta-analysis used to develop the PHASES scoring system. In this scoring system, aneurysm rupture risks for the first 5 years can be estimated according to population, hypertension, age, size, earlier subarachnoid hemorrhage history, and aneurysm site. Discussion: To conduct and publish large-scale cohort studies, it is important to: 1) never publish main results before the final paper, 2) fix the protocol and analysis plan prior to the study, 3) establish good collaboration with a statistician, and 4) raise a simple but important research question.
The natural history of intracranial arterial dissection is not well known. This study was conducted to elucidate the serial changes of radiographic findings and the long-term outcomes in both hemorrhagic and non-hemorrhagic patients who underwent intracranial vertebrobasilar artery dissection. Among 200 patients who underwent intracranial arterial dissection of the vertebrobasilar system, 99 (49.5%) were conservatively managed. These patients were divided into two groups: the hemorrhagic group (H, subarachnoid hemorrhage; n = 24 patients) and non-hemorrhagic group (NH, ischemia or headache; n = 75). Age, site of dissection, initial radiological findings and serial changes, follow-up period, and long-term outcome were analyzed. Outcomes were evaluated using the Glasgow Outcome Scale. Results: The median ages were 54 and 52 years in the H and NH groups, respectively. In both groups, the vertebral artery was most commonly affected, followed by the basilar artery. Regarding radiographic findings, the pearl-and-string sign was the most common initial finding in the H group. Conversely, tapering, narrowing, or occlusion was the most common finding in the NH group. As for serial changes in radiographic findings, no change was most frequent in both groups, followed by improvement. These changes mostly occurred within a few months in the H group but over several years in the NH group. The mean follow-up periods were 7.2 and 5.7 years in the H and NH groups, respectively. Regarding long-term outcomes, in the H group, 15 patients (62.5%) had a good recovery, and 7 (29.2%) died. In the NH group, 58 patients (77.5%) recovered, and 7 (9.3%) died. The cause of poor outcome was initial hemorrhage or subsequent rupture in the H group. Poor outcomes in the NH group were primarily due to systemic problems. These results demonstrate the long-term radiological changes and outcomes associated with the intracranial arterial dissection of the vertebrobasilar system. However, these findings are insufficient to argue the natural history of this disease because patients who received surgical treatment were excluded from this study.
The purpose of this study is to suggest a new and simple classification of anterior communicating artery (ACoA) aneurysms based on the relation between A1 direction and aneurysm projection. We analyzed the effect of morphological features on angiographic outcome after coil embolization for ACoA aneurysms. We conducted a retrospective case review of 78 consecutive patients (35 men and 43 women) with ACoA aneurysms treated at our institution from September 2004 to October 2013. The patterns of A1 direction and aneurysm projection allowed the classification of ACoA aneurysms into four types: S-S type, A1 with superior direction and aneurysm with superior projection; S-I type, A1 with superior direction and aneurysm with inferior projection; I-I type, A1 with inferior direction and aneurysm with inferior projection; I-S type, A1 with inferior direction and aneurysm with superior projection. The percentage distribution of each type is as follows: S-S, 28.2%; I-I, 44.9%; S-I, 11.5%; and I-S, 15.4%. The I-I type is the most common type of aneurysm in this classification. Thirty-five patients were treated with endovascular coil embolization, and the average volume embolization ratios were as follows: S-S, 34.2%; I-I, 28.2%; S-I, 25.8%; and I-S, 26.6%. Complete occlusion (Raymond grade 1) was achieved at 90% in S-S, 35.7% in I-I, 42.9% in S-I, and 0% in I-S. The S-S and I-I types are likely to result in complete occlusion or neck remnant. The S-I and I-S types are likely to result in body filling. It is thought that coil embolization was likely to have resulted unfavorably in direction mismatch types (S-I, I-S) because the relation between A1 direction and aneurysm projection directly affects the intraoperative deliverability and stability of the microcatheter. In conclusion, this classification provides useful information for ACoA aneurysm treatment in a simple and immediate manner.
Spontaneous cervical arterial dissection (SCAD) is a non-traumatic tear or disruption in the walls of the internal carotid arteries. SCAD is the leading cause of stroke in patients <45 years of age, accounting for almost one-fourth of strokes in this population. However, standard criteria for its treatment have not been established. Therefore, we reviewed five cases of SCAD (four men, one woman; mean age 47.0 ± 12.7 years) treated between November 2009 and January 2013 to determine the appropriate treatment. Three patients had cerebral infarctions; of them, two underwent revascularization surgery. One was treated with superficial temporal artery-middle cerebral artery bypass (STA-MCA bypass) and ligation of the cervical internal carotid artery. The other was treated with radial artery grafted external carotid artery-MCA bypass and ligation of the cervical internal carotid artery. The other three patients were treated with conservative therapy, which included an antithrombotic agent in two. Only one patient was not treated with an antithrombotic agent because he had no cerebral ischemia. Of all patients, only one, who was treated with STA-MCA bypass and ligation of the cervical internal carotid artery, progressed to cerebral ischemia. SCAD is reversible in most cases. Therefore, conservative therapy is recommended, except in cases of progressing hemodynamic ischemia and requirement of revascularization because there is no time for recovery.
Background: Cerebral hyperperfusion syndrome is a potential complication of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease (MMD). Prophylactic blood pressure lowering in combination with the use of minocycline, a neuroprotective antibiotic agent, has been suggested to reduce the risk of cerebral hyperperfusion. We therefore aimed to evaluate the results of this procedure in our larger series. Methods: N-isopropyl-p-[123I]iodoamphetamine single-photon emission computed tomography was performed 1 and 7 days after STA-MCA anastomosis on 89 hemispheres from 75 consecutive patients with MMD (10-66, mean 38 years old). Postoperative systolic blood pressure was strictly controlled under 130 mmHg with the intra-operative and postoperative intravenous administration of minocycline hydrochloride (200 mg/day). Then we investigated the incidence of perioperative neurological deterioration and radiological adverse events such as delayed intracranial hemorrhage. Results: All patients underwent technically successful revascularization surgeries, and none of them suffered permanent neurological deterioration postoperatively. Three patients suffered transient ischemic attack in the acute stage (3.4%), and one patient suffered delayed intracerebral hemorrhage (ICH), which caused transient aphasia (1.1%). Six patients (mean age of 51.3 years) demonstrated delayed intracranial hemorrhage (subarachnoid hemorrhage in 5, and ICH in one) (6.7%) while five of them remained asymptomatic. Conclusion: The administration of minocycline with strict blood pressure control may represent secure and effective postoperative management after STA-MCA anastomosis for MMD, while delayed intracranial hemorrhage, either symptomatic or asymptomatic, is a potential complication of this procedure.
We describe the usefulness of intraoperative angiography (IOA) in identifying a recipient artery in extracranial-intracranial (EC-IC) bypass surgery. A 38-year-old woman presented with transient ischemic attacks that were resistant to aggressive medical treatment. Circulation delay at the M4 segment of the central artery was considered to be responsible for her symptoms. Due to the resistance to aggressive medical therapy, EC-IC bypass was planned. IOA was employed because of the need for definite detection of the central artery. The modality was helpful in determining the location of the skin incision and craniotomy as well as in identifying the recipient artery. The bypass was successfully constructed, and her symptoms were significantly reduced after the surgery.
To minimize operative invasiveness, we propose ultra-small craniotomy for cerebral aneurysm surgery. The size is 4 × 3 cm, which is about twice the size of a 100-yen coin. The sphenoid ridge should be rongeured away to flatten the floor from the frontal base to the temporal pole. For the craniotomy, the sylvian vein is divided into the frontal and temporal lobes in a 2:1 ratio. In skin incision, care should be taken not to injure the facial nerve during division into the frontalis and orbitalis oculi muscles. From the cosmetic viewpoint, the 1- to 2-cm forehead incision used in this technique is not visible. Moreover, this technique can be performed by a beginner neurosurgeon, without any special tool for the procedure.