Superficial Temporal Artery-middle Cerebral Artery Research Articles

Adult Moyamoya disease: 320-Multidetector row CT for evaluation of revascularization in STA–MCA bypasses surgery

PurposeTo evaluate the utility of 320-multidetector row whole-brain computed tomography perfusion (WBCTP) and whole-head subtracted dynamic angiography (WHSDCTA) for assessing the revascularization of blood flow after superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery in adults with Moyamoya disease (MD) in the short and long term. Patients and methods320-multidetector row WBCTP and WHSDCTA were applied in 20 patients with MD before and after surgery (for an average of 3 days and 3 months). The bypass arteries were investigated using WHSDCTA and compared with DSA. The regions of interests (ROIs) in the surgical and mirror sides of the cerebral cortex were drawn on a Vitrea Workstation. Cerebral blood volume (CBV), time to peak (TTP), cerebral blood flow (CBF), mean transit time (MTT), and delay time were recorded. Preoperative and postoperative perfusion parameters in the MCA distribution were compared using the paired t-test. ResultsWHSDCTA could clearly demonstrate 24 bypass arteries in 26 arteries for 20 patients, results which were in accordance with the results of digital subtraction angiography (DSA). When comparing preoperative values to those within 3 days after surgery, only TTP and delay time were significantly different (P<0.05). Values of CBV, TTP, CBF, delay time, and MTT 3 months after surgery were significantly different (P<0.05) from those of preoperative perfusion. ConclusionThese data suggest that 320-multidetector row WBCTP and WHSDCTA can be used to evaluate the revascularization of blood flow after STA–MCA bypass surgery in patients with MD in the short and long term.

Investigating the mechanisms of perioperative ischemic stroke in the Carotid Occlusion Surgery Study

The Carotid Occlusion Surgery Study (COSS) was a large, prospective clinical trial that examined whether superficial temporal artery-middle cerebral artery (STA-MCA) bypass, in addition to best medical therapy, reduced the risk of ipsilateral ischemic stroke in patients with carotid artery occlusion and hemodynamic cerebral ischemia. Despite improved cerebral hemodynamics and excellent bypass graft patency rates, COSS failed to show a benefit for the surgical group with respect to ipsilateral stroke recurrence at 2 years after treatment. This was due to a lower than expected rate of recurrent ipsilateral stroke in the medically treated group and a high rate of perioperative ipsilateral strokes in the surgical group. Critics of the trial have cited surgeon inexperience and technical difficulties related to the performance of the bypass graft as a leading cause of failure of the trial. The authors retrospectively identified all patients from the COSS with an ipsilateral, perioperative (< 30 days) ischemic stroke after STA-MCA cortical branch anastomosis. Study records, operative notes, stroke adjudication forms, and imaging studies were reviewed. Ischemic strokes were characterized as bypass graft related or non-bypass graft related based on clinical and radiographic findings. Fourteen of 93 surgically treated patients experienced an ipsilateral, perioperative ischemic stroke. Postoperatively, the mean oxygen extraction fraction (OEF) ratio between the symptomatic and asymptomatic cerebral hemisphere significantly improved in these patients (1.30 ± 0.18 preoperative vs 1.12 ± 0.11 postoperative; p = 0.02), but did not normalize. In this cohort, total MCA occlusion time during the anastomosis (54.3 ± 23.5 minutes) was no different from the MCA occlusion time in those surgical patients who did not have a perioperative stroke (45.4 ± 24.2 minutes, p = 0.2). Bypass graft patency rates in patients with a perioperative stroke were 92% at 30 days (11 of 12 patients with patency data) and 83% at last follow-up visit (10 of 12 patients with patency data). These patency rates were not significantly different from those achieved at 30 days (100%; 76 of 76 patients with patency data; p = 0.14) and at last follow-up (99%; 71 of 72 patients with patency data; p = 0.052) in patients without a perioperative stroke. Eighty-six percent (12 of 14 patients) of strokes were likely attributable to factors unrelated to the STA-MCA anastomosis. Only 21% of strokes (3 of 14 patients) were in the territory of the recipient vessel and likely related to technical performance of the anastomosis itself. One patient was thought to have dual stroke mechanisms. Only a small minority of ipsilateral, perioperative ischemic strokes in the COSS could be attributed to technical problems of the bypass anastomosis. The majority of ischemic strokes could not be ascribed to this cause and were most likely due to patient hemodynamic fragility and the inability of patients to tolerate surgery.

Occlusion of M1 segment after superficial temporal artery-middle cerebral artery bypass in a giant M1 aneurysm with Onyx-34 injected via a double-lumen balloon under balloon inflation

A 29-year-old patient attended our institution for recurrent strokes related to a giant partially thrombosed M1 aneurysm. Superficial temporal artery-middle cerebral artery (STA-MCA) bypass and subsequent occlusion of both the...

Perfusion-Weighted Magnetic Resonance Imaging Used in Assessing Hemodynamics following Superficial Temporal Artery-Middle Cerebral Artery Bypass in Patients with Moyamoya Disease

Background: The best strategy to assess the changes in brain hemodynamics following superficial temporal artery (STA)-middle cerebral artery (MCA) bypass in patients with Moyamoya disease remains unknown. The purpose of the present study was to assess cerebral hemodynamics using perfusion-weighted magnetic resonance imaging (PWI) before and after STA-MCA bypass surgery in patients with Moyamoya disease. Methods: STA-MCA bypass surgeries were performed on 23 symptomatic cerebral hemispheres in 21 patients (11 females/10 males, age 11-62 years) with Moyamoya disease due to cerebral ischemic attacks or intracranial hemorrhages. Brain PWI images were obtained in the frontal lobes, the temporal lobes, the occipital lobes, and the basal ganglia before and after STA-MCA bypass surgery. The relative parameters cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) derived from PWI were calculated. All patients underwent CT angiography or MR angiography after surgery in order to confirm the patency of bypass. Results: According to preoperative PWI, there was significant hypoperfusion in the symptomatic temporal and frontal lobes. According to postoperative PWI, the regional CBF had increased in both the temporal and frontal lobes on the operative side (p < 0.05, versus preoperative data). In the postoperative CBV maps, there was a significant decrease in the occipital lobe on the operative side (p < 0.05, versus preoperative data). The postoperative MTT in the temporal lobe, frontal lobe and basal ganglia area on the operative side was short, relative to the preoperative MTT (p < 0.05). The CT angiography or MR angiography imaging demonstrated patency of the bypass in all patients after surgery. During the follow-up period, all patients showed significant improvement in neurological function postoperatively. Conclusions: This study demonstrates that STA-MCA bypass is a safe and effective surgical treatment for Moyamoya disease. PWI enables an effective and objective assessment of hemodynamics before and after STA-MCA bypass surgery in patients with Moyamoya disease.

Predictive factors of symptomatic cerebral hyperperfusion after superficial temporal artery-middle cerebral artery anastomosis in adult patients with moyamoya disease

Symptomatic cerebral hyperperfusion (SCH) is a potential complication after superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis in patients with moyamoya disease. This retrospective study was designed to determine factors associated with SCH after STA-MCA anastomosis in adult moyamoya patients. Eighty-two adult moyamoya patients undergoing STA-MCA anastomosis between July 2005 and December 2010 were enrolled. Laboratory data such as haemoglobin and white blood cell (WBC) count, preoperative (patient characteristic data, initial clinical manifestation, the angiographic staging), intraoperative (surgical time, the operative side, anaesthetic technique, fluid balance, arterial pressure, arterial partial pressure of carbon dioxide, the lowest haematocrit, and intraoperative transfusion), and postoperative (arterial pressure, Acute Physiology and Chronic Health Evaluation II score) data were collected and used as predictable factors for postoperative SCH, in which a focal intense increase in cerebral blood flow at the anastomosis site was shown in postoperative single-photon emission computed tomography. Among 82 patients with 99 surgeries, 39 patients (47 sides, 47%) suffered from transient neurological deterioration due to SCH from 1 to 9 days after operation (median: 2 days), which was sustained for 1-14 days (median: 7 days). The operation on the dominant hemisphere [odds ratio (OR), 5.09; 95% confidence interval (CI), 2.07-12.54, P<0.001] was an independent risk factor for SCH. Also, WBC count on postoperative day 1 was significantly correlated with SCH (OR 1.19; 95%CI, 1.02-1.38, P=0.029). The operation on the dominant hemisphere and increased postoperative WBC count may be associated with SCH after STA-MCA anastomosis in adult-onset moyamoya patients.

Moyamoya Associated with Down Syndrome: Management Strategies

Introduction: We describe four patients with Down syndrome and moyamoya who were referred for possible cerebral revascularization. The unique features associated with these cases are presented. Methods: A retrospective case review of all inpatient and outpatient records and neuroimaging studies was performed. Results: Three of the four patients were women; all had bilateral moyamoya. Ages ranged from 18 to 34 years. One patient presented with repeated transient ischemic episodes (TIAs) despite antiplatelet therapy. One had repeated “spells” that mimicked complex partial seizures, but seizure activity could not be demonstrated on electroencephalogram. One patient presented with a minor stroke, and the final patient presented with headaches only with no evidence of ischemia. Superficial temporal artery-middle cerebral artery (STA-MCA) bypass was performed in two patients, bilateral in one. One patient underwent bilateral pial synangiosis procedures. One patient was managed with aspirin alone. Conclusions: Down syndrome may be associated with moyamoya. Patients with Down syndrome who develop symptoms of cerebral ischemia should be evaluated for this condition. Cerebral revascularization may be warranted in selected cases, and results have been favorable in these patients.

Cerebral Hyperperfusion Syndrome After Superficial Temporal Artery-middle Cerebral Artery Bypass for Severe Intracranial Steno-occlusive Disease

Intracranial stenoses carry increased risk for cerebral ischemia. We perform external carotid-internal carotid (EC-IC) artery bypass in our patients with severe stenosis of the intracranial internal carotid (ICA) or middle cerebral artery (MCA) with impaired cerebral vasodilatory reserve (CVR). To evaluate cerebral hemodynamics and cerebral hyperperfusion syndrome (HPS) in patients who develop focal neurological deficits after EC-IC bypass surgery. Patients with severe intracranial ICA or MCA stenosis and impaired CVR on transcranial Doppler (TCD) derived breath-holding index (BHI) were evaluated with acetazolamide-challenged technetium-99m hexamethylpropyleneamineoxime-single-photon emission computed tomography (SPECT). EC-IC bypass surgery was offered to patients with impaired CVR on SPECT. Close monitoring was performed in patients developing focal neurological deficits within 7 days of surgery. Of 112 patients with severe intracranial ICA/MCA stenosis, 77 (69%) showed impaired CVR and 46 (41%) underwent EC-IC bypass. Transient neurological deficits within 7 days of surgery developed in 8 (17%). HPS was confirmed by CT perfusion and/or SPECT in 7 cases. A strong correlation was observed between HPS and preoperative TCD-BHI values (0%, 6.3%, and 41% in patients with BHI 0.3-0.69, 0-0.3 and <0, respectively; P = .012). HPS patients showed more than a 50% increase in MCA flow velocity on TCD (compared with preoperative values) on the operated side (63.3% vs 3.3% on control side, P < .001). Meticulous control of blood pressure and hydration led to rapid and complete resolution of neurological deficits in all cases. Symptomatic cerebral HPS is common in the early postoperative period after EC-IC bypass surgery. Early diagnosis and appropriate management might prevent the complications of this syndrome.

Abstract WP161: Improvement in Cerebral Hemodynamic Parameters and outcomes after Superficial Temporal Artery- Middle Cerebral Artery Bypass in Patients with Severe Steno-occlusive Disease of Intracranial Carotid and Middle Cerebral Artery

Background and Objective —Older as well as the recent extracranial-intracranial (EC/IC) bypass trial in patients with symptomatic carotid occlusion failed to demonstrate reduction in stroke recurrence. However, the role of superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery in patients with symptomatic intracranial steno-occlusive disease has been evaluated scarcely. We evaluated the changes in various hemodynamic parameters in patients with severe steno-occlusive disease of intracranial internal carotid (ICA) or middle cerebral artery (MCA) who underwent STA-MCA bypass surgery for impaired cerebral vasodilatory reserve (CVR). Methods —Patients with severe steno-occlusive disease of intracranial ICA or MCA underwent transcranial Doppler (TCD) ultrasonography and CVR assessment using breath-holding index (BHI). Patients with impaired BHI (&lt;0.69) were further evaluated with acetazolamide-challenged hexamethylpropyleneamine oxime single-photon emission computed tomography (HMPAO-SPECT). STA-MCA bypass surgery was offered to patients with impaired CVR on SPECT. TCD and SPECT were repeated in all patients at 4±1 months and they were followed-up for cerebral ischemic events. Results —112 patients (73males, mean age 56yrs; range 23-78yrs) fulfilled our inclusion criteria. HMPAO-SPECT demonstrated impaired CVR in 77 (69%) patients. Forty-six of them underwent STA-MCA bypass while 31 received best medical treatment. TCD and acetazolamide-challenged HMPAO-SPECT repeated 4±1 months after surgery showed significant improvement in STA-MCA bypass group. During follow-up (mean 24 months; range 4 to 33months), only 6/46 (13%) patients in bypass group developed cerebral ischemic events as compared to14/31 (45%) cases on medical therapy (absolute risk reduction 32%, p=0.008). Conclusion —STA-MCA bypass surgery in carefully selected patients with symptomatic severe intracranial steno-occlusive disease results in significant improvement in hemodynamic parameters and reduction in stroke recurrence

Double-Barrel Bypass for Cerebral Ischemia

In selected patients, extracranial-intracranial bypass remains an important treatment for the prevention of stroke. Traditionally, superficial temporal artery-middle cerebral artery (STA-MCA) bypass uses 1 STA branch. We have adopted a "double-barrel" technique in which both branches are joined with MCA recipients in distinct vascular territories. To assess the feasibility of routinely using both branches of the STA for cerebral revascularization. Ten consecutive patients underwent double-barrel bypass. Patients were selected if they demonstrated symptomatic MCA hypoperfusion resistant to medical therapy or had symptomatic moyamoya disease. Flow-directed bypass was performed to augment flow to the territories most at risk in each case, based on preoperative and intraoperative data. Computed tomography perfusion was routinely performed to evaluate baseline deficits and postoperative augmentation. Clinical data were analyzed to assess patient demographics and outcomes. The double-barrel bypass was no more difficult technically than the traditional approach, with the second branch harvested through a small satellite incision. By isolating temporary occlusion to each territory, there was no additional ischemia to each brain region. No intraoperative complications or wound-healing issues occurred. Postoperative computed tomography perfusion studies all showed improvement, and delayed vascular imaging demonstrated universal graft patency. Nine of 10 patients have been asymptomatic since surgery, whereas 1 patient demonstrated symptoms in a separate vascular distribution. Double-barrel STA-MCA bypass is both feasible and potentially advantageous. In our series, both bypass branches remained patent, augmenting flow to the territories most at need.

Electroencephalographic Evaluation of Cerebral Hyperperfusion Syndrome Following Superficial Temporal Artery-Middle Cerebral Artery Anastomosis

Low-flow bypass, such as superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis, can result in cerebral hyperperfusion syndrome (CHS). The present study evaluated the pathophysiological conditions of CHS through the use of repeated electroencephalography (EEG). Among a total of 22 patients who underwent STA-MCA anastomosis over a course of 4 years, 3 patients were diagnosed with CHS based on clinical symptoms and neuroradiological examinations, including cerebral blood flow evaluation. Case 1 and Case 2 developed CHS on postoperative day 1, when EEG demonstrated focal slow waves on the frontal region of the operated side, indicating cortical dysfunction in these areas. Although prompt recovery of these EEG findings was noted with improvement of the clinical symptoms in Case 1, Case 2 developed an intracranial hemorrhage on postoperative day 5, when EEG clearly depicted persistent nonconvulsive status epilepticus (NCSE) after control of convulsive status epilepticus. In contrast, the clinical onset in Case 3 was delayed to postoperative day 6 and EEG revealed frequent ictal discharges in the operated hemisphere, although convulsive seizures were not apparent. Administration of anticonvulsants was performed after the diagnosis of NCSE, and complete recovery from CHS was achieved. Although the pathophysiology of CHS is cortical dysfunction, ictal hyperperfusion associated with NCSE could be included. The present findings emphasize the importance of repeated EEG examinations in the differential diagnosis of the various types of pathophysiological conditions of CHS.

網膜虚血により視力の急性増悪を呈した内頚動脈慢性閉塞症に対して血行再建術を施行した1例

網膜虚血により視力の急性増悪を呈した内頚動脈慢性閉塞症に対して血行再建術を施行した1例

The Usefulness of the Ivy Sign on Fluid-Attenuated Intensity Recovery Images in Improved Brain Hemodynamic Changes after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Adult Patients with Moyamoya Disease

ObjectiveMR perfusion and single photon emission computerized tomography (SPECT) are well known imaging studies to evaluate hemodynamic change between prior to and following superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis in moyamoya disease. But their side effects and invasiveness make discomfort to patients. We evaluated the ivy sign on MR fluid attenuated inversion recovery (FLAIR) images in adult patients with moyamoya disease and compared it with result of SPECT and MR perfusion images.MethodsWe enrolled twelve patients (thirteen cases) who were diagnosed with moyamoya disease and underwent STA-MCA anastomosis at our medical institution during a period ranging from September of 2010 to December of 2012. The presence of the ivy sign on MR FLAIR images was classified as Negative (0), Minimal (1), and Positive (2). Regions were classified into four territories: the anterior cerebral artery (ACA), the anterior MCA, the posterior MCA and the posterior cerebral artery.ResultsIvy signs on preoperative and postoperative MR FLAIR were improved (8 and 4 in the ACA regions, 13 and 4 in the anterior MCA regions and 19 and 9 in the posterior MCA regions). Like this result, the cerebrovascular reserve (CVR) on SPECT was significantly increased in the sum of CVR in same regions after STA-MCA anastomosis.ConclusionAfter STA-MCA anastomosis, ivy signs were decreased in the cerebral hemisphere. As compared with conventional diagnostic modalities such as SPECT and MR perfusion images, the ivy sign on MR FLAIR is considered as a useful indicator in detecting brain hemodynamic changes between preoperatively and postoperatively in adult moyamoya patients.

浅側頭動脈-中大脳動脈吻合部に発生, 増大した未破裂脳動脈瘤の1手術例

浅側頭動脈-中大脳動脈吻合部に発生, 増大した未破裂脳動脈瘤の1手術例

Cerebral revascularization with superficial temporal - middle cerebral artery anastomosis for complete carotid occlusion: An emerging modality for preventing recurrent stroke

Complete long segment carotid occlusion presents a treatment challenge. These patients cannot be managed adequately by endarterectomy or stenting. Despite best medical management, many continue to develop recurrent strokes. In this select group of patients, there may be role for flow augmentation techniques like superficial temporal-middle cerebral artery bypass. We report a patient who was thus successfully treated and remains asymptomatic. The relevant literature is reviewed.

Surgical results of the Carotid Occlusion Surgery Study.

The Carotid Occlusion Surgery Study (COSS) was conducted to determine if superficial temporal artery-middle cerebral artery (STA-MCA) bypass, when added to the best medical therapy, would reduce subsequent ipsilateral stroke in patients with complete internal carotid artery (ICA) occlusion and an elevated oxygen extraction fraction (OEF) in the cerebral hemisphere distal to the occlusion. A recent publication documented the methodology of the COSS in detail and briefly outlined the major findings of the trial. The surgical results of the COSS are described in detail in this report. The COSS was a prospective, parallel-group, 1:1 randomized, open-label, blinded-adjudication treatment trial. Participants, who had angiographically demonstrated complete occlusion of the ICA causing either a transient ischemic attack or ischemic stroke within 120 days and hemodynamic cerebral ischemia indicated by an increased OEF measured by PET, were randomized to either surgical or medical treatment. One hundred ninety-five patients were randomized: 97 to the surgical group and 98 to the medical group. The surgical patients underwent an STA-MCA cortical branch anastomosis. In the intention-to-treat analysis, the 2-year rates for the primary end point were 21% for the surgical group and 22.7% for the medical group (p = 0.78, log-rank test). Fourteen (15%) of the 93 patients who had undergone an arterial bypass had a primary end point ipsilateral hemispheric stroke in the 30-day postoperative period, 12 within 2 days after surgery. The STA-MCA arterial bypass patency rate was 98% at the 30-day postoperative visit and 96% at the last follow-up examination. The STA-MCA arterial bypass markedly improved, although it did not normalize, the level of elevated OEF in the symptomatic cerebral hemisphere. Five surgically treated and 1 nonsurgically treated patients in the surgical group had a primary end point ipsilateral hemispheric stroke after the 30-day postoperative period. No baseline characteristics or intraoperative variables revealed those who would experience a procedure-related stroke. Despite excellent bypass graft patency and improved cerebral hemodynamics, STA-MCA anastomosis did not provide an overall benefit regarding ipsilateral 2-year stroke recurrence, mainly because of a much better than expected stroke recurrence rate (22.7%) in the medical group, but also because of a significant postoperative stroke rate (15%). Clinical trial registration no.: NCT00029146.

Perioperative complications of superficial temporal artery to middle cerebral artery bypass for the treatment of complex middle cerebral artery aneurysms

ObjectOnly a few studies have reported the risk of ischemic complications occurring when superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis is performed during surgery for complex MCA aneurysms. Subjects and methodsThis is a retrospective study of 10 patients (age 52–73) with MCA aneurysms treated with revascularization surgery. The aneurysms were 10–50mm in size (mean: 21mm). We studied the causes and frequency of ischemic complications by analyzing postoperative magnetic resonance imaging. ResultsPostoperative diffusion-imaging confirmed ischemic complications in six of the 10 patients (in two of the five ruptured aneurysms and in four of the five unruptured). The ischemic complications that observed were infarction of the lenticulostriate artery territory in three cases, cortical infarction in two cases, and cerebral infarction that was likely to be due to cerebral vasospasm in one case. In one case, both cortical infarction and infarction of the lenticulostriate artery territory were observed. The Glasgow Outcome Scale (GOS) scores at the time of discharge indicated good recovery (GR) and moderate disability (MD) in seven cases, severe disability (SD) in two cases, and death (D) in one case. ConclusionsThe present study suggests the possibility that STA–MCA anastamosis in surgeries for MCA aneurysms can be performed with comparatively better safety. However, the temporary occlusion time with this surgery is longer than that with a temporary clipping for aneurysmal surgery; thus, we believe that adequate countermeasures are required to prevent ischemic complications.

Common features in patients with intracerebral hemorrhage following superficial temporal artery-middle cerebral artery bypass in steno-occlusive cerebrovascular disease.

Five patients treated for intracranial cerebral hemorrhage after superficial temporal artery-middle cerebral artery bypass in Xuwu Hospital, Capital Medical University, Beijing, China, from 2005-2011 were included in this study. Prior to superficial temporal artery-middle cerebral artery bypass, all patients showed diminished cerebrovascular reactivity and an ipsilateral ischemic lesion. Intracranial cerebral hemorrhage developed within 1–4 days following superficial temporal artery-middle cerebral artery bypass. Transcranial Doppler showed increased middle cerebral artery velocity of 50–100% in the operated hemisphere. These findings suggested that focal hyperperfusion, an ipsilateral ischemic lesion and diminished cerebrovascular reactivity are the important characteristics of intracerebral hemorrhage following superficial temporal artery-middle cerebral artery bypass in patients with steno-occlusive cerebrovascular disease.

Ruptured De Novo Aneurysm Arising at a Site Remote From the Anastomosis 14 Years After Superficial Temporal Artery-Middle Cerebral Artery Bypass

The long-term outcome of superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is unclear. We report a very rare case of a de novo aneurysm after bypass surgery. A 57-year-old woman who underwent STA-MCA bypass and internal carotid artery aneurysm treatment 14 years earlier developed a subarachnoid hemorrhage and a temporal lobe hematoma on the same side as the anastomosis. Angiography showed excellent patency of the STA bypass and a ruptured de novo saccular aneurysm at a site remote from the anastomosis. Neck clipping and hematoma evacuation were performed on the second day, and postoperative angiography showed complete aneurysmal clipping. The aneurysm was considered to be caused by hemodynamic stress because it was remote from the anastomosis and had developed after a prolonged interval of 14 years; furthermore, the aneurysm projected because of the hemodynamic force of the STA perfusion. This is the first reported case of a de novo MCA aneurysm that developed at a site remote from STA-MCA anastomosis because of hemodynamic force. Therefore, long-term control of blood pressure and repeated imaging examination should be performed to confirm patency and to identify aneurysm formation after STA-MCA bypass.

Hypertrophy of the Vasa Vasorum

The vasa vasorum is a network of microvessels that supplies nutrients to the vessel wall itself. In pathologic conditions, the vasa vasorum can develop as potential collateral channels. Previous research documents revascularization through hypertrophy of the vasa vasorum after occlusion of the carotid artery. However, the relationship between the cerebral vascular demands and the hypertrophy of the vasa vasorum has not been well delineated by functional studies. A 66-year-old man presented with left hemiparesis, dysarthria, and hemineglect. Magnetic resonance imaging revealed an acute infarction in the vascular territory of the right middle cerebral artery. Transfemoral cerebral angiography revealed occlusion of the right proximal internal carotid artery (ICA). Single-photon emission computed tomography study showed decreased vascular reserve in the right cerebral hemisphere. Right superficial temporal artery-middle cerebral artery bypass surgery was performed in an attempt to improve hemispheric perfusion. Follow-up angiography 1 year later showed revascularization of the distal ICA by the hypertrophied vasa vasorum. Follow-up single-photon emission computed tomography study showed persistent decreased vascular reserve. In cases of ICA occlusion, a 1-year or less hungry period for the cerebral vascular demand may activate potential collateral channels of the vasa vasorum. In addition to the metabolic demand of the occluded vessel wall itself, the vascular demands of the hypoperfused brain may be a trigger factor that leads to hypertrophy of the vasa vasorum as collateral channels.

Efficacy of Prophylactic Blood Pressure Lowering according to a Standardized Postoperative Management Protocol to Prevent Symptomatic Cerebral Hyperperfusion after Direct Revascularization Surgery for Moyamoya Disease

Background: Cerebral hyperperfusion is a potential complication of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis for moyamoya disease, but the optimal postoperative management has not been determined. Aggressive blood pressure lowering is controversial because of the risk of ischemic complications. Objective: To establish the optimal postoperative management protocol to prevent symptomatic cerebral hyperperfusion in moyamoya disease. Methods: N-isopropyl-p-[¹²³I]-iodoamphetamine single-photon emission computed tomography was performed 1 and 7 days after STA-MCA anastomosis on 152 hemispheres from 108 consecutive patients with moyamoya disease (2–69, mean 33.3 years). Between 2004 and 2007 (period 1), 65 patients were maintained under normotensive conditions after 93 operations, and only patients with cerebral hyperperfusion underwent blood pressure lowering. Between 2008 and 2010 (period 2), all 43 patients were prospectively subjected to intensive blood pressure lowering (<130 mm Hg of systolic blood pressure) immediately after 59 operations. Then the incidence of symptomatic cerebral hyperperfusion was compared between the two groups. Results: Systolic blood pressure the day after surgery was significantly lower in period 2 (mean, 120.9 mm Hg) than in period 1 (133.9 mm Hg) (p < 0.0001). Symptomatic cerebral hyperperfusion was seen in 22 patients during period 1 (23 hemispheres, 24.7%), but only in 4 patients during period 2 (6.7%, p = 0.0047). Multivariate analysis revealed that prophylactic blood pressure lowering was significantly associated with the prevention of symptomatic cerebral hyperperfusion (p = 0.015). Symptomatic cerebral hyperperfusion was relieved in all patients without developing a permanent neurological deficit due to cerebral hyperperfusion. Conclusion: Prophylactic blood pressure lowering prevents symptomatic cerebral hyperperfusion after STA-MCA anastomosis in patients with moyamoya disease. Accurate diagnosis of cerebral hyperperfusion and blood pressure lowering, and considering the severity of hemodynamic compromise in the contralateral and/or remote areas are essential for postoperative management of moyamoya disease.