Enhanced analysis of intracerebral arterioveneous malformations by the intraoperative use of analytical indocyanine green videoangiography: technical note

In cerebral arterioveneous malformations (AVMs) detailed intraoperative identification of feeding arteries, nidal vessels and draining veins is crucial for surgery. Intraoperative imaging techniques like indocyanine green videoangiography (ICG-VAG) provide information about vessel architecture and patency, but do not allow time-dependent analysis of intravascular blood flow. Here we report on our first experiences with analytical indocyanine green videoangiography (aICG-VAG) using FLOW 800 software as a useful tool for assessing the time-dependent intraoperative blood flow during surgical removal of cerebral AVMs. Microsope-integrated colour-encoded aICG-VAG was used for the surgical treatment of a 38-year-old woman diagnosed with an incidental AVM, Spetzler Martin grade I, of the left frontal lobe and of a 26-year-old man suffering from seizures caused by a symptomatic AVM, Spetzler Martin grade III, of the right temporal lobe. Analytical ICG-VAG visualization was intraoperatively correlated with in situ micro-Doppler investigation, as well as preoperative and postoperative digital subtraction angiography (DSA). Analytical ICG-VAG is fast, easy to handle and integrates intuitively into surgical procedures. It allows colour-encoded visualization of blood flow distribution with high temporal and spatial resolution. Superficial major and minor feeding arteries can be clearly separated from the nidus and draining veins. Effects of stepwise vessel obliteration on velocity and direction of AVM blood flow can be objectified. High quality of visualization, however, is limited to the site of surgery. Colour-encoded aICG-VAG with FLOW 800 enables intraoperative real-time analysis of arterial and venous vessel architecture and might, therefore, increase efficacy and safety of neurovascular surgery in a selected subset of superficial AVMs.     

Venous Reddening as a Possible Sign of Hyperperfusion after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis for Moyamoya Disease: Case Report

Here we report a case of moyamoya disease in which cortical veins reddened after superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis, following postoperative hyperperfusion. A 37-year-old man with moyamoya disease suffered cerebral infarction in his right hemisphere. Single photon emission computed tomography (SPECT) showed impaired cerebral blood flow (CBF) in both cerebral hemispheres. The patient underwent STA-MCA anastomosis in the right cerebral hemisphere. During operation, soon after declamping the STA, cortical veins near the anastomosis site changed its color from blue to red. This change was repeatable by clamping and declamping of the STA. Postoperative SPECT and computed tomography (CT) demonstrated increased CBF and subarachnoid hemorrhage at the anastomosis site, suggesting the occurrence of postoperative hyperperfusion. By strictly controlling the patient''s blood pressure, the syndrome resolved 1 week after the operation. We propose that the venous reddening after STA-MCA anastomosis may be a sign of postoperative hyperperfusion.     

Intraoperative Measurement of Arterial Blood Flow Using a Transit Time Flowmeter: Monitoring of Hemodynamic Changes During Cerebrovascular Surgery

Summary  Background. The purpose of this study was to examine the utility and reliability of arterial flow measurements made with a transit time ultrasonic flowmeter for monitoring blood flow changes during intracranial and carotid surgery.  Method. A total of 25 patients underwent intra-operative arterial blood flow measurements. The pulsatile flow curve and mean flow values were obtained using 1- to 6-mm transit time probes with a dual channel flowmeter. Four cases underwent aneurysm clipping, 11 cases superficial temporal artery (STA) – middle cerebral artery (MCA) bypass, 2 cases external carotid artery (ECA) – radial artery – MCA bypass for aneurysm trapping, and 8 cases carotid endarterectomy. In aneurysm clipping, blood flow in the branches distal to the aneurysm was measured before and after clipping. Blood flow in the STA was measured before and after STA-MCA anastomosis, and blood flow in the internal carotid artery (ICA) cervical portion was measured during carotid endarterectomy. Blood flow in the MCA and STA was monitored during radial artery grafting.  Findings. Blood flow in the STA was elevated after STA-MCA anastomosis. However, post-operative hyperperfusion syndrome was found in some cases whose flow elevation was over 50 ml/min. Also in one case of carotid stenosis, of which blood flow of ICA was elevated to 400 ml/min after carotid endarterectomy, hyperperfusion syndrome was found after surgery. In the cases of MCA aneurysm clipping, decreasing of M2 flow was detected when clipping caused bifurcation stenosis.  Interpretation. We found transit time flow measurement useful for management of cerebrovascular surgery: the technique was simple to use and provided stable, reliable results. The method was able to reveal distal branch flow diminution in aneurysm clipping, or residual flow during temporary clipping in aneurysm surgery, and has the potential to predict post-operative complications such as hyperperfusion by signalling over-elevation of donor artery flow in bypass surgery or ICA flow in carotid surgery.     

Superficial temporal artery to middle cerebral artery anastomosis. Intraoperative evaluation by fluorescein angiography and xenon-133 clearance.

Fluorescein angiography and xenon-133 (133Xe) clearance studies were performed during surgery on 15 patients who were undergoing superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis. Fourteen patients had occlusive disease of the internal carotid artery (ICA), and one patient had severe stenosis of the MCA. Before anastomosis, fluorescein angiography showed slow filling of the MCA branches through collateral channels. Focal areas of impaired microcirculatory filling and washout were seen in the territory of severely sclerotic cortical arteries. The findings of preanastomotic 133Xe clearance studies were variable and a uniform pattern of regional cerebral blood flow (rCBF) changes was not defined. In 55% of the patients, rCBF was reduced to 25 ml/100 gm/min or less at one or more detector sites. Fluorescein angiography provided an immediate assessment of anastomotic patency and clearly displayed the distribution of blood entering the epicerebral circulation through the STA. In 67% of patients, multiple MCA cortical branches filled with fluorescein, whereas in 33% filling was restricted to the receptor artery territory. An immediate, substantial (greater than or equal to 15 ml/100 gm/min) increase in rCBF was demonstrated in 73% of patients after anastomosis. The rCBF changes were consistently better in patients with donor and receptor arteries greater than 1 mm in diameter. Redistribution of collateral input acted to increase rCBF in areas distant from the anastomotic site. Some improvement in fluorescein circulation and rCBF also was seen in cortex supplied by sclerotic MCA branches.     

Patch angioplasty to repair the arteriotomy defect in the wall of the middle cerebral artery after failure of superficial temporal artery-middle cerebral artery anastomosis in moyamoya disease--case report

A 65-year-old woman presented with moyamoya disease associated with a saccular aneurysm of the posterior cerebral artery. The surgical plan required superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis to be conducted before neck clipping of the aneurysm to provide collateral flow via the STA to prevent ischemia if temporary occlusion of the parent artery of the aneurysm was needed. However, the anastomotic procedure failed because the STA was occluded at the site of temporary clip application. End-to-end anastomosis of the STA was planned after excising the occluded site of the STA, but end-to-end anastomosis could not be performed because the donor artery was too short for anastomosis to the branch of the MCA. Therefore, patch grafting using a piece of wall of the STA was performed to repair the arteriotomy defect in the wall of the MCA, followed by neck clipping of the saccular aneurysm in the posterior circulation via the subtemporal approach. Vascular reconstruction can be recommended if arterial anastomosis between a superficial skin artery and a branch of the MCA is impossible due to an intraoperative accident or technical difficulty and reperfusion is necessary.     

Indocyanine green videoangiography for assessment of postoperative hyperperfusion in moyamoya disease

Background

Postoperative cerebral hyperperfusion (HP) is a notable complication that occurs more frequently in moyamoya disease (MMD) than in atherosclerosis. This study aimed to clarify the characteristics of intraoperative indocyanine green (ICG) videoangiography in MMD and atherosclerotic disease in terms of postoperative HP.

Methods

This prospective study included 47 patients with 60 sides that underwent superior temporal artery (STA)-middle cerebral artery (MCA) single bypass. ICG videoangiography was performed after revascularization. The ICG time intensity curve was recorded in the STA, proximal MCA, distal MCA, and superficial Sylvian vein, and the angiographic differences among adult MMD, pediatric MMD, and atherosclerosis were analyzed.

Results

Twenty-two patients (27 sides) had adult MMD, 14 patients (22 sides) had pediatric MMD, and 11 patients (11 sides) had atherosclerosis. Postoperative HP was significantly higher in adult MMD (40.7 %) than in pediatric MMD (18.2 %) and atherosclerosis (0 %). Adult MMD with HP was associated with a longer ICG peak time (P?<?0.001). There was no correlation between the ICG peak time and preoperative cerebral blood flow or vascular reserve. The ratio of the vessel caliber was also higher in adult MMD with HP (P?<?0.001).

Conclusions

ICG videoangiography provides different characteristics of bypass flow among adult MMD, pediatric MMD, and atherosclerosis. Poor run-off and stagnation of blood flow from the STA might contribute to postoperative HP in MMD. The occurrence of postoperative HP in MMD could depend on two factors: donor STA size and poor run-off and integrity of the blood brain barrier in the recipient MCA.     

Effect of proximal occlusion on anastomosis patency in dogs

This study compared the superficial temporal-middle cerebral artery (STA-MCA) anastomosis patency in animals with and without proximal embolic middle cerebral artery (MCA) occlusion. Sixteen dogs underwent STA-MCA bypass in association with silicone embolization of the MCA via an internal carotid injection. Animals re-explored 3 to 5 days postoperatively with evaluation of anastomosis patency by Evans blue injection and direct cutting of the STA demonstrated that 10 of 10 dogs with proximal MCA emboli had a patent STA-MCA anastomosis, whereas only 2 of 6 animals without an embolus lodged in the proximal middle cerebral artery had a patent connection. The likelihood of the anastomosis remaining open seems to be greatly influenced by the potential flow gradient between the extracranial and intracranial circulations (Neurosurgery, 5: 596--597, 1979).     

Intraoperative monitoring of cerebral blood oxygenation and hemodynamics during extracranial-intracranial bypass surgery by a newly developed visible light spectroscopy system

BACKGROUND: Cerebrovascular reconstruction procedures run the risk of changing the balance between oxygen supply and consumption during surgery. We assessed the value of visual light spectroscopy for detecting changes in cerebral blood oxygenation (CBO) during superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis. METHODS: We developed a VLS monitoring system which permits continuous monitoring of CBO changes during surgery. Using the VLS, we evaluated the CBO changes in the MCA territory on the lesion side in 18 patients who underwent STA-MCA anastomosis. RESULTS: Temporary occlusion of the MCA (M4 portion) did not change the CBO in 17 patients. However, in the patient with dissecting aneurysm, it caused decreases of oxyhemoglobin and cortical oxygen saturation (CoSo(2)) associated with an increase of deoxyhemoglobin, although these CBO changes were normalized by STA blood flow. In 5 patients, STA blood flow increased the oxyhemoglobin and CoSo(2) and decreased the deoxyhemoglobin, indicating that cortical blood flow (CoBF) was increased. The CoSo(2) before anastomosis was significantly low in the patients who showed an increase of CoSo(2) by STA blood flow (63.0% +/- 2.5%) as compared with those who did not (72.0 +/- 6.1%, P = .024). CONCLUSION: Temporary occlusion of a cortical artery during bypass surgery did not affect the CBO in patients who had chronic cerebral ischemia, but caused acute ischemia in the patient who did not. STA blood flow increased the CoBF during surgery more frequently in patients who showed a low perfusion pressure. The VLS monitoring system is considered useful for evaluating bypass function and facilitates safe and accurate bypass surgery.     

Posterior Auricular Artery-Middle Cerebral Artery Bypass: A Rare Superficial Temporal Artery Variant with Well-developed Posterior Auricular Artery—Case Report

The posterior auricular artery (PAA) is one of the branches of the external carotid artery, but is usually too small for use as a donor artery for middle cerebral artery (MCA) territory revascularization. An extremely unusual case of PAA-MCA anastomosis was performed in a patient requiring MCA territory revascularization because the superficial temporal artery (STA) parietal branch was absent and the PAA was large enough. A 65-year-old man developed mild motor weakness in the right extremities caused by multiple small infarctions. Single photon emission computed tomography (CT) revealed deterioration of the vascular reserve capacity in the left MCA area. Cerebral angiography showed severe stenosis in the C2 portion of the left internal carotid artery, absence of the parietal branch of the left STA, and a well-developed PAA extending to the parietal area. The patient underwent STA (frontal branch)-MCA and PAA-MCA double anastomosis, and has suffered no stroke or transient ischemic attack. The STA with no bifurcation is known as a rare variation. The PAA also occurs with size variations but well-developed PAA is thought to be extremely rare. PAA can be used as a donor artery for MCA territory revascularization if the vessel size is suitable. Preoperative evaluation of the anatomy is mandatory for harvesting the arteries.     

Hemodynamics and changes after STA–MCA anastomosis in moyamoya disease and atherosclerotic cerebrovascular disease measured by micro-Doppler ultrasonography

Moyamoya disease (MMD) and atherosclerotic cerebrovascular disease (ACVD) differ in angiographic appearance and probably hemodynamics. Pediatric MMD (PMMD) usually presents with cerebral ischemia, while intracranial hemorrhage is more common in adult MMD (AMMD), suggesting differences in cerebral hemodynamics. We analyzed the cortical flow velocity and direction of recipient arteries using micro-Doppler ultrasonography to evaluate the cortical circulation before and after anastomosis in MMD and ACVD. Twenty-eight patients with adult MMD (AMMD), 7 with pediatric MMD (PMMD), 16 with ACVD, and 12 control patients were studied. A micro-Doppler probe was applied on the cortical recipient artery (A4 or M4) before and after anastomosis. Systolic maximum flow velocity (V _max) and blood flow direction were investigated at proximal and distal parts of anastomosed sites in recipient arteries. Pre- and postoperative regional cerebral blood flow was measured by cold xenon-computed tomography (Xe-CT). Before anastomosis, retrograde cortical flow was significantly more common in PMMD patients, and V _max in cortical artery was significantly lower in AMMD patients. Bypass surgery changed the direction of blood flow from the anastomosis site to proximal and distal sites of the recipient artery in most patients, but pre-anastomosis flow direction was preserved more frequently in PMMD patients. The rate of V _max increase after anastomosis was significantly higher in AMMD than in PMMD (11.6?±?9.8 vs. 3.9?±?1.8; P?=?0.01). Micro-Doppler ultrasonography identified differences in cortical circulation among AMMD, PMMD, and ACVD. In AMMD, significantly low velocity in the cortical artery was observed before anastomosis, and bypass surgery reversed the flow and significantly increased flow velocity. The data of PMMD showed unique hemodynamics of the cortical artery before anastomosis, characterized by a higher frequency of retrograde flow and preserved velocity. The V _max increase rate was significantly higher in patients with postoperative cerebral hyperperfusion on Xe-CT, and further study is warranted to validate the clinical use of intraoperative micro-Doppler monitoring to predict postoperative hyperperfusion.     

Two cases of main trunk artery occlusion associated with multiple cerebral aneurysms

We report 2 cases of multiple aneurysms (AN) associated with main trunk artery occlusion. CASE 1: A 52-year-old male was admitted to our hospital with dysarthria and weakness of the right side of the body. Computed tomography (CT) showed cerebral infarction in the left corona radiata. MR angiography and conventional angiography showed occlusion of the left middle cerebral artery (MCA) and saccular aneurysms (ANs) at the origin of the anterior communicating artery (A-com) and bifurcation of the right MCA. Subsequent 123I-IMP-single photon emission tomography (SPECT) revealed marked reduction of cerebral blood flow and disturbed reactivity to acetazolamide in the left cerebral hemisphere. Superficial temporal artery (STA)-MCA anastomosis was performed to improve cerebral blood flow and reduce hemodynamic stress for AN of the A-com and right MCA. At 5 months after the first operation, neck clipping was performed successfully for the non-ruptured A-com AN and right MCA AN. CASE 2: A 65-year-old male was admitted to our hospital. CT revealed subarachnoid hemorrhage (SAH), and 3D-computed tomographic angiography (CTA) and cerebral angiography showed basilar top AN, A-com AN and right MCA AN associated with right internal carotid artery occlusion. Right ACA and MCA territories were visualized from the A-com artery and posterior cerebral artery. STA-MCA anastomosis was performed to improve cerebral blood flow and reduce hemodynamic stress for ANs. In the same operation, successful neck clipping was performed for BA top AN and right MCA AN. In such cases as these, particularly in ischemic cases associated with main trunk artery occlusion, it was important to consider surgery for AN after STA-MCA anastomosis in anticipation of improved cerebral blood flow and reduce hemodynamic stress for AN.     

Ruptured infectious aneurysms of the distal MCA treated with trapping and STA-MCA bypass surgery

We describe two patients with ruptured infectious aneurysms of the distal MCA, which were successfully treated by trapping and superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery. Our patients had not experienced any ischemic attack postoperatively. Trapping and STA-MCA bypass surgery can be a useful option.     

Higher magnification microsurgical repair of donor artery dissection in superficial temporal artery to middle cerebral artery anastomosis--technical note

Donor artery dissection is a known cause of technical failure in microvascular anastomosis. A method for detection and direct repair of donor artery dissection before superficial temporal artery (STA) to middle cerebral artery (MCA) anastomosis is described using a high magnification operating microscope (maximum 50.4× magnification). Before STA-MCA anastomosis, the stump of the STA is stained using methylrosaniline chloride (pyoctaninum blue) and is observed under higher magnifications. Microsurgical suturing of the arterial dissection is performed before the anastomosis procedure under the high magnification microscope. This method was used in two patients with symptomatic hemodynamic cerebrovascular occlusive disease. Postoperative angiography revealed good patency and no complications occurred. This method may be useful for detection and direct repair of arterial dissection in small vessel walls before STA-MCA anastomosis.     

Radiation-induced cerebrovasculopathy of the distal middle cerebral artery and distal posterior cerebral artery--case report

A 15-year-old girl underwent partial removal of a pituitary adenoma followed by local irradiation of the brain with a total of 70 Gy through two lateral opposing ports. Twenty years later, she experienced frequent transient ischemic attacks with left sensory disturbance. Cerebral angiography revealed stenoses of the right distal middle cerebral artery (MCA) and the right distal posterior cerebral artery without net-like vessels. There was a severe decrease of vasoreactivity in the right hemisphere. Right superficial temporal artery (STA)-MCA anastomosis was performed. Her neurological deficits were resolved and perfusion reserve capacity had markedly improved 6 months later. We recommend STA-MCA anastomosis in such cases.     

STA-ACA bypass using the contralateral STA as an interposition graft for the treatment of complex ACA aneurysms: report of two cases and a review of the literature

Bypass surgery has been used as a remedy for the complex cerebral aneurysm, which was unsolved with the clipping method. However, little has been reported about bypass options for anterior cerebral artery (ACA) aneurysms. The authors experienced two patients with complex ACA aneurysms, large fusiform and large thrombosed aneurysms involving the distal A1 and proximal A2 segments, respectively. To achieve complete obliteration of the aneurysm, we performed a superficial temporal artery (STA)-ACA bypass using contralateral STA as interposition grafts with endovascular trapping without any ischemic events. These cases show that STA-ACA bypass using contralateral STA interposition graft is a feasible option to maintain blood supply to the ACA territory if a proximal ACA lesion requires trapping.     

STA-ACA anastomosis with interposed vein graft; a case report]

We report our experience with the use of three saphenous vein grafts for treating advanced occlusive cerebrovascular disease in the anterior cerebral artery (ACA) in two patients. Superficial temporal artery (STA)-ACA anastomosis with interposed vein graft is thought to be indicated for patients who have STA of insufficient length to anastomose to the ACA. Vein graft has already been demonstrated to be applicable in extracranial-intracranial artery bypass, as well as in aorto-coronary bypass. Two factors considered to be essential for successful revascularization are technical proficiency, including protection from drying, smooth approximation of vessels, and proper orientation of the graft, and the relative size of donor and recipient vessels. Because the vein graft must be anastomosed with the proximal ACA to reduce the size discrepancy between vessels, prolonged interruption of circulation during suturing is inevitable. Our operative results suggest that anastomosis to a superficial branch of the ACA just distal to the interhemispheric fissure seems to be preferable to anastomosis using vein graft, and we recommend the option of vein graft only when the STA cannot be used.     

Temporal change of 3-T magnetic resonance imaging/angiography during symptomatic cerebral hyperperfusion following superficial temporal artery-middle cerebral artery anastomosis in a patient with adult-onset moyamoya disease

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is a safe and effective treatment for moyamoya disease, although recent evidence suggests its substantial risk for symptomatic cerebral hyperperfusion. The diagnostic value of single-photon emission computed tomography (SPECT) for postoperative hyperperfusion in moyamoya patients is well established, but that of magnetic resonance (MR) imaging/angiography is undetermined. A 22-year-old woman with hemorrhagic-onset moyamoya disease underwent STA-MCA anastomosis on the right hemisphere, but she suffered from transient left hemiparesis and facial paresis owing to cerebral hyperperfusion from 3 to 11 days after surgery as delineated by SPECT. The time-sequential 3-T MR angiography revealed intense high signal of donor STA and dilated branches of MCA around the site of the anastomosis. These findings were most prominent at 8 days after surgery, when her neurologic signs were most apparent. Intensive blood pressure control relieved her symptom and she was discharged without neurologic deficit. MR findings normalized 3 months later. The characteristic findings of 3-T MR angiography, which was not evident by 1.5-T MR angiography in the previous studies, may reflect intrinsic pathology of postoperative cerebral hyperperfusion. It could be a useful diagnostic tool after revascularization surgery for moyamoya disease.     

Temporal change of 3-T magnetic resonance imaging/angiography during symptomatic cerebral hyperperfusion following superficial temporal artery–middle cerebral artery anastomosis in a patient with adult-onset moyamoya disease

Superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis is a safe and effective treatment for moyamoya disease, although recent evidence suggests its substantial risk for symptomatic cerebral hyperperfusion. The diagnostic value of single-photon emission computed tomography (SPECT) for postoperative hyperperfusion in moyamoya patients is well established, but that of magnetic resonance (MR) imaging/angiography is undetermined. A 22-year-old woman with hemorrhagic-onset moyamoya disease underwent STA-MCA anastomosis on the right hemisphere, but she suffered from transient left hemiparesis and facial paresis owing to cerebral hyperperfusion from 3 to 11 days after surgery as delineated by SPECT. The time-sequential 3-T MR angiography revealed intense high signal of donor STA and dilated branches of MCA around the site of the anastomosis. These findings were most prominent at 8 days after surgery, when her neurologic signs were most apparent. Intensive blood pressure control relieved her symptom and she was discharged without neurologic deficit. MR findings normalized 3 months later. The characteristic findings of 3-T MR angiography, which was not evident by 1.5-T MR angiography in the previous studies, may reflect intrinsic pathology of postoperative cerebral hyperperfusion. It could be a useful diagnostic tool after revascularization surgery for moyamoya disease.     

Augmentation of cerebral blood flow induced by hemodilution in stroke patients after superficial temporal-middle cerebral arterial bypass operation

Experimental hemodilutional therapy has been shown to raise collateral perfusion to acutely ischemic brain regions distal to occluded internal carotid (ICA) and middle cerebral (MCA) arteries and to reduce infarct size. Superficial temporal (STA)-MCA anastomosis surgically establishes additional regional collateralization, and this bypass angiographically enlarges over time. Despite bypass patency verification by Doppler recording made at the edge of the craniectomy, the microsurgical STA-MCA anastomosis in 11 stroke patients did not produce early changes in cerebral perfusion parameters in the MCA territory of either hemisphere as determined by 133xenon inhalation. Therefore, hemodilution was initiated in an effort to increase cerebral perfusion during this marginal period when the STA was beginning to dilate progressively. Incremental venesections with equal intravenous volume replacement with 5% human serum albumin caused a significant lowering of the hematocrit from 40 +/- 1 to 33 +/- 1%. This isovolemic hemodilutional therapy resulted in significant mean regional cerebral blood flow (rCBF) elevations of 23 +/- 5% (SE) in the bypassed MCA territory and of 25 +/- 6% in the opposite MCA region. The mean gray flow (F1) in the involved and homologous MCA regions significantly increased 27 +/- 8% and 30 +/- 11%, respectively. Similarly, the initial slope index (ISI2) significantly rose by 17 +/- 5% in the bypassed MCA territory and by 18 +/- 6% in the homologous region. These data objectively support the premise that reductions in hematocrit without intravascular volume expansion augment cerebral blood flow, probably by reducing blood viscosity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pre-operative higher hematocrit and lower total protein levels are independent risk factors for cerebral hyperperfusion syndrome after superficial temporal artery–middle cerebral artery anastomosis with pial synangiosis in adult moyamoya disease patients—case-control study

Neurosurgical Review - Superficial temporal artery (STA)–middle cerebral artery (MCA) anastomosis is a standard treatment for adult moyamoya disease (MMD) patients. Cerebral hyperperfusion...