Childhood moyamoya disease before and after encephalo-duro-arterio-synangiosis: an angiographic study

Superficial Temporal Artery Size Changes After Encephaloduroarteriosynangiosis for the Treatment of Moyamoya Disease

BACKGROUND AND OBJECTIVE

Surgery is the mainstay of stroke prevention in patients with symptomatic moyamoya disease (MMD). We present the results of a single-center retrospective study of indirect revascularization surgery for adult MMD, emphasizing angiographic outcomes, including dilation of the superficial temporal artery and formation of new collaterals.

METHODS

A prospectively maintained database of procedures performed for MMD was reviewed. Adult patients treated with indirect revascularization and with long-term angiographic follow-up were included. Preoperative and postoperative angiographic images and baseline and procedural characteristics were analyzed. A Wilcoxon signed-rank test was used to test the hypothesis that the superficial temporal artery increases in diameter postoperatively.

RESULTS

We identified 40 hemispheres in 27 patients, of which 35 had a sufficient angiographic follow-up. Bilateral procedures were performed on 16 patients. Most patients were female (72.5%), with a median age of 43 years old. The most common clinical presentation was ischemic stroke in 59.3% of cases. All patients underwent an encephaloduroarteriosynangiosis for treatment. A follow-up angiogram was performed at a median of 13.8 months postoperatively, showing superficial temporal artery (STA)-derived collaterals in 71.4% and collateral ingrowth via the burr holes in 61.8% of cases. Disease progression was evident in 34.3% of hemispheres. The normalized STA diameter was significantly increased postoperatively (2.4 to 3 mm; P < 0.05). A univariate analysis revealed that transdural collaterals and hyperlipidemia may affect collateral ingrowth from the STA, and no other patient- or procedure-related factors, including replacement of the bone flap, impacted on this.

CONCLUSIONS

A significant increase in STA diameter on follow-up angiography after encephaloduroarteriosynangiosis was found; however, this was not directly associated with STA collateral development. Rates of postoperative transient ischemic attacks were low, and no patients had a new ischemic or hemorrhagic stroke at last follow-up. The presence of transdural collaterals and the absence of hyperlipidemia were associated with STA collateral development on follow-up angiography, but the causality of this finding is unclear.

Axial Magnetic Resonance Angiography in Evaluating Revascularization after Indirect Bypass Surgery for Moyamoya Axial Magnetic Resonance Angiography after Indirect Bypass

INTRODUCTION

At our institution, revascularization after indirect moyamoya surgery is routinely evaluated using magnetic resonance angiography (MRA) rather than catheter angiography. In this paper, we review how revascularization can be visualized on axial MRA and compare its visualization on MRA to that on catheter angiography. We also compare clinical outcomes of patients followed with routine postoperative MRA with outcomes of patients followed with routine catheter angiography.

METHODS

We retrospectively reviewed the records of all patients treated at our institution who underwent unilateral encephaloduroarteriosynangiosis (EDAS) and/or pial synangiosis between the ages of 1 and 21 years and between December 31, 2003, and May 1, 2021. We included patients who underwent EDAS/pial synangiosis at other hospitals as long as they met all inclusion criteria. Inclusion criteria included having a preoperative MRA within 18 months of surgery and a postoperative MRA 3-30 months after surgery. Clinical outcomes included development of postoperative stroke and transient ischemic attacks (TIAs) and changes in symptoms (improved, unchanged, or worsened), including seizures, balance issues, and headaches. Clinical outcomes were compared between patients who had routine postoperative MRA only versus those who had routine postoperative angiograms, with or without routine MRA. For each surgery, we determined the ratios of the diameters and areas of the donor vessel and the contralateral corresponding vessel, as well as the relative signal intensities of these two vessels, on preoperative and 3- to 30-month postoperative MRA. We did the same for the middle meningeal artery (MMA) ipsilateral to the donor artery and the contralateral MMA. We assessed changes from pre- to post-operation in diameter ratios, area ratios, relative signal intensity, ivy sign, and in brain perfusion on arterial spin labeled (ASL) imaging. MRI and MRA measures of revascularization and flow were compared to Matsushima grades in patients who had postoperative catheter angiograms.

RESULTS

Fifty-one operations for 42 unique patients were included. There were no significant differences in the rates of postoperative strokes, postoperative TIAs, changes in symptoms, or new symptoms after surgeries evaluated by routine postoperative MRA versus catheter angiogram (p = 0.282, 1, 0.664, and 0.727, respectively). There were significant associations between greater collateralization on postoperative MRA and greater median increases in preoperative-to-postoperative ratios of donor-vessel-over-contralateral-vessel diameter (p = 0.0461), ipsilateral-MMA-over-contralateral-MMA diameter (p = 0.0135), and the summed donor and ipsilateral MMA diameters over the summed contralateral vessel diameters (p < 0.001). The median increase in the ratio of the donor vessel and contralateral corresponding vessel diameters was significantly higher for Matsushima grade A versus B (p = 0.036). The median increase in the ratio of the sum of donor and ipsilateral MMA diameters over the sum of the contralateral vessel diameters was significantly higher for improved-versus-unchanged perfusion on ASL imaging (p = 0.0074). There was a nonsignificant association between greater postoperative collateralization on MRA and Matsushima grade (p = 0.1160).

CONCLUSION

Cerebral revascularization after EDAS and pial synangiosis can be evaluated on axial MRA by comparing the diameter and/or signal intensity of the donor vessel and corresponding contralateral vessel, as well as the ipsilateral and contralateral MMA, on postoperative-versus-preoperative MRA. The use of routine postoperative MRA rather than catheter angiography does not appear to negatively affect outcomes.

Color Doppler ultrasonography as an alternative tool for postoperative evaluation of collaterals after indirect revascularization surgery in Moyamoya disease

The cerebral hypoperfusion caused by chronic progressive stenosis or occlusion of intracranial arteries in moyamoya disease can be treated by direct bypass or indirect revascularization procedures. The extent of collaterals from the external carotid artery (ECA) after indirect revascularization surgery is the key point of angiographic follow-up, and the invasiveness of angiography impelled us to investigate the role of ultrasonography in the evaluation of collaterals. We hypothesized that the collaterals shown on angiography might produce corresponding hemodynamic changes in color Doppler ultrasonography. We prospectively recruited moyamoya patients who underwent indirect revascularization surgery and received both preoperative and postoperative angiography and color Doppler ultrasound studies. The collaterals on angiography were graded according to Matsushima method. A total of 21 patients (age, 17 ± 10.2 years) with 24 operated hemispheres were enrolled. Patients who showed better collateral establishment by angiography had higher end-diastolic velocity (EDV), lower resistance index (RI), and larger flow volume in the superficial temporal artery (STA) and ECA (all p < 0.05). In STA, increase of EDV greater than 13.5 cm/sec or reduction of RI greater than 0.19 after operation corresponded to 94% of Matsushima grade A+B. In ECA, post-operative EDV greater than 22 cm/sec or increase of EDV greater than 6.4 cm/sec also corresponded to 94% of Matsushima grade A+B. Our findings revealed potential roles of color Doppler ultrasonography in identifying patients with poor collaterals after indirect revascularization procedures.

Risk Factors for Epilepsy Recurrence after Revascularization in Pediatric Patients with Moyamoya Disease

OBJECTIVE

We aimed to explore the risk factors of seizure recurrence and the optimal surgical procedure for epileptic pediatric patients with moyamoya disease (MMD).

METHODS

We reviewed 696 consecutive patients with MMD admitted to our hospital from 2009 to 2015. Pediatric patients with MMD who had seizures before revascularization were identified. We summarized the characteristics of seizures in pediatric patients with MMD and analyzed the predictive factors of recurrent seizure events.

RESULTS

We identified 28 pediatric patients with MMD who had seizures before revascularization. During follow-up (median 42 months), 7 patients (25.0%) experienced recurrent seizures. In the multivariate analysis, the duration of epilepsy was an independent predictor for postoperative seizure recurrences (odds ratio 3.84, 95% confidence interval 1.54-24.34; P = .035). The 2 common surgical modalities of MMD (direct and indirect bypass) had no significant difference in future seizure prevention in pediatric patients with MMD with epilepsy.

CONCLUSIONS

We identified the duration of epilepsy as an independent risk factor for recurrent seizure after revascularization in pediatric patients with MMD.

Incidence, clinical features, and treatment of familial moyamoya in pediatric patients: a single-institution series

OBJECTIVE Limited data exist on familial moyamoya in children. The purpose of this study was to characterize presentation and outcomes of pediatric moyamoya patients who have relatives diagnosed with moyamoya. METHODS The authors performed a single-institution retrospective analysis of a case series including all surgically treated children with moyamoya with first- or second-degree relatives with moyamoya. Clinical and radiographic characteristics were analyzed, along with surgical outcomes. RESULTS A total of 537 patients underwent surgery for moyamoya during the study period. Eighteen of those patients (3.4% of the total series) had moyamoya and a family history of moyamoya and were included in this study. Of these 18 patients, 14 were non-twin siblings, and the remaining 4 represented 2 pairs of identical (affected) twins. The presentation was predominantly ischemic (72%), but 4 patients (33%) were asymptomatic when they were found to have moyamoya. Bilateral disease was present in 13 patients (72%). Radiographic stroke prevalence (67%), Suzuki grade (3.3), and angiographic findings were comparable to findings in nonfamilial moyamoya patients. Thirty revascularization procedures were performed, with a 3.3% operative stroke rate per hemisphere and no new strokes in an average follow-up period of 4.5 years. CONCLUSIONS In a North American surgical series, familial moyamoya existed in 3.4% of cases, and was distinguished by manifesting in a broad range of ethnic groups, with a higher proportion of male patients and increased rates of asymptomatic and unilateral disease in comparison to nonfamilial moyamoya. Screening indications remain controversial and the current data are used to suggest guidelines. Surgical therapy is warranted, effective, and durable in these patients, but patients should be carefully selected.

Angiographic Structural Differentiation between Native Arteriogenesis and Therapeutic Synangiosis in Intracranial Arterial Steno-Occlusive Disease

BACKGROUND AND PURPOSE

Encephaloduroarteriosynangiosis has been shown to generate collateral vessels from the extracranial-to-intracranial circulation in patients with Moyamoya disease and intracranial arterial steno-occlusive disease. The mechanisms involved are not well-understood. We hypothesized that angiogenesis is the leading mechanism forming collaterals after encephaloduroarteriosynangiosis because there are no pre-existing connections. Angiogenesis-generated collaterals should exhibit higher architectural complexity compared with innate collaterals.

MATERIALS AND METHODS

Pre- and postoperative digital subtraction angiograms were analyzed in patients enrolled in a prospective trial of encephaloduroarteriosynangiosis surgery. Branching angioscore, tortuosity index, and local connected fractal dimension were compared between innate and postoperative collaterals.

RESULTS

One hundred one angiograms (50 preoperative, 51 postoperative) were analyzed from 44 patients (22 with intracranial atherosclerosis and 22 with Moyamoya disease). There was a significantly higher median branching angioscore (13 versus 4, P < .001) and a lower median tortuosity index (1.08 versus 1.76, P < .001) in the encephaloduroarteriosynangiosis collaterals compared with innate collaterals. Higher mean local fractal dimension peaks (1.28 ± 0.1 versus 1.16 ± 0.11, P < .001) were observed in the encephaloduroarteriosynangiosis collaterals compared with innate collaterals for both intracranial atherosclerosis (P < .001) and Moyamoya disease (P < .001) groups. The observed increase in high connectivity was greater in the intracranial atherosclerosis group compared with patients with Moyamoya disease (P = .01).

CONCLUSIONS

The higher median branching angioscore and local connected fractal dimension, along with the lower median tortuosity index of encephaloduroarteriosynangiosis collaterals, are consistent with the greater complexity observed in the process of sprouting and splitting associated with angiogenesis.

Clinical importance of the middle meningeal artery: A review of the literature

The middle meningeal artery (MMA) is a very important artery in neurosurgery. Many diseases, including dural arteriovenous fistula (DAVF), pseudoaneurysm, true aneurysm, traumatic arteriovenous fistula (AVF), moyamoya disease (MMD), recurrent chronic subdural hematoma (CSDH), migraine and meningioma, can involve the MMA. In these diseases, the lesions occur in either the MMA itself and treatment is necessary, or the MMA is used as the pathway to treat the lesions; therefore, the MMA is very important to the development and treatment of a variety of neurosurgical diseases. However, no systematic review describing the importance of MMA has been published. In this study, we used the PUBMED database to perform a review of the literature on the MMA to increase our understanding of its role in neurosurgery. After performing this review, we found that the MMA was commonly used to access DAVFs and meningiomas. Pseudoaneurysms and true aneurysms in the MMA can be effectively treated via endovascular or surgical removal. In MMD, the MMA plays a very important role in the development of collateral circulation and indirect revascularization. For recurrent CDSHs, after burr hole irrigation and drainage have failed, MMA embolization may be attempted. The MMA can also contribute to the occurrence and treatment of migraines. Because the ophthalmic artery can ectopically originate from the MMA, caution must be taken to avoid causing damage to the MMA during operations.

Quantitative Digital Subtraction Angiography in Pediatric Moyamoya Disease

Moyamoya disease is a unique cerebrovascular disorder characterized by idiopathic progressive stenosis at the terminal portion of the internal carotid artery (ICA) and fine vascular network. The aim of this review is to present the clinical application of quantitative digital subtraction angiography (QDSA) in pediatric moyamoya disease. Using conventional angiographic data and postprocessing software, QDSA provides time-contrast intensity curves and then displays the peak time (T_max) and area under the curve (AUC). These parameters of QDSA can be used as surrogate markers for the hemodynamic evaluation of disease severity and quantification of postoperative neovascularization in moyamoya disease.

Down syndrome and moyamoya: clinical presentation and surgical management

OBJECT Moyamoya can cause cerebral ischemia and stroke in Down syndrome (DS) patients. In this study, the authors defined a surgically treated population of patients with DS and moyamoya and compared their clinical presentation, response to surgical treatment, and long-term prognosis with those of the general population of patients with moyamoya but without DS. METHODS This study was a retrospective review of a consecutive operative series of moyamoya patients with DS treated at Boston Children's Hospital from 1985 through 2012. RESULTS Thirty-two patients, average age 9.7 years (range 1.8-29.3 years), underwent surgery for moyamoya in association with DS. The majority presented with ischemic symptoms (87% stroke, 42% transient ischemic attacks). Twenty-four patients (75%) had congenital heart disease. Nineteen patients (59%) had bilateral moyamoya on presentation, and 13 presented with unilateral disease, of which 2 progressed to surgery on the opposite side at a later date. Patients were followed for a median of 7.5 years (1-20.2 years) after surgery, with no patients lost to follow-up. Follow-up arteriography demonstrated Matsushima Grade A collaterals in 29 of 39 (74%) hemispheres, Grade B in 5 (13%), and Grade C in 5 (13%). Complications included postoperative strokes in 2 patients, which occurred within 48 hours of surgery in both; one of these patients had arm weakness and the other confusion (both had recovered completely at follow-up). Seizures occurred in 5 patients perioperatively, including one who had a new seizure disorder related to hypocalcemia. CONCLUSIONS Moyamoya disease is a cause of stroke in patients with DS. Both the incidence of preoperative stroke (87% vs 67%) and the average age at diagnosis for children under age 21 (8.4 vs 6.5 years) were greater in patients with DS and moyamoya than in the general moyamoya surgical population, suggesting a possible delay in reaching a correct diagnosis of the cause of cerebral ischemia in the DS patient population. Pial synangiosis provided long-term protection from stroke in all patients treated.

Foramen spinosum and middle meningeal artery in moyamoya disease: Preliminary results of a pilot study

OBJECT

This study investigated whether the size of the middle cranial fossa foramina reflects the severity of moyamoya disease (MMD).

METHODS

It compared 20 adult patients managed without surgical revascularization with 2 age- and sex-matched controls. MR angiography scores were assigned by the severity of occlusive changes of the internal carotid artery, the middle cerebral artery, the anterior and the posterior cerebral arteries and the signals of the distal branches of these arteries. These scores were stratified into MR angiography grades (Houkin's grade: 1-4). The relationships between the Houkin's grade and the size of the foramen spinosum (FS), foramen ovale, carotid canal and middle meningeal artery (MMA) were evaluated.

RESULTS

Simple regression analysis showed the correlation between the Houkin's grade and the bilateral FS (right, r = 0.56, p = 0.010; left, r = 0.46, p = 0.044) and MMA (right, r = 0.89, p = 0.0050; left, r = 0.47, p = 0.036). It also showed the correlation between the FS and MMA (right, r = 0.53, p = 0.018; left, r = 0.55, p = 0.013). There were no significant differences between the Houkin's grade, the size of the carotid canal and the foramen ovale.

CONCLUSIONS

The larger FS and MMA on brain CT, which might be performed for patients suspected of intracranial lesions, could aid the diagnosis of MMD.

Differential clinical outcomes following encephaloduroarteriosynangiosis in pediatric moyamoya disease presenting with epilepsy or ischemia

PURPOSE

The purpose of this study was to compare clinical outcomes and surgical results after encephaloduroarteriosynangiosis (EDAS) in pediatric patients with Moyamoya disease that manifested as either ischemia or epileptic seizures.

METHODS

We treated 23 children who underwent EDAS; we divided the patients into either ischemic or epileptic groups according to the individuals' clinical presentation. Group Ia included those who mainly presented with cerebral ischemia in the form of preoperative transient ischemic attacks (TIA), while Group Ib presented with ischemia in the form of irreversible neurologic deficits or proven cerebral infarcts. Group II included those who presented with epileptic seizures rather than cerebral ischemia. We compared the clinical outcomes and surgical results following EDAS in the three groups.

RESULTS

We grouped the patients into three groups according to their main preoperative clinical symptoms (Group Ia n = 10, Group Ib n = 6, and Group II n = 7). Group II, the epileptic manifestation group, tended to show more favorable clinical outcomes compared to the ischemic manifestation group, especially the severe ischemic group. However, there were no significant differences in postoperative neuroimaging and hemodynamic assessments between the groups.

CONCLUSIONS

EDAS is a safe and effective surgical technique that prevents epileptic seizures and shows more favorable clinical outcomes when used in patients with Moyamoya disease presenting with epileptic seizures compared to cerebral ischemia.

Expression of cellular retinoic acid-binding protein-I (CRABP-I) in the cerebrospinal fluid of adult onset moyamoya disease and its association with clinical presentation and postoperative haemodynamic change

OBJECTIVE

The elevation of cellular retinoic acid-binding protein-I (CRABP-I) has been suggested as a candidate in the pathogenesis of paediatric moyamoya disease (MMD). However, few studies have addressed CRABP-I in adult onset MMD. The aim of this study was to examine the expression of CRABP-I in the cerebrospinal fluid (CSF) of adult onset MMD, and to evaluate its association with clinical presentation and postoperative haemodynamic change.

METHODS

This study examined the CSF from 103 patients: bilateral MMD, n=58 (56.3%); unilateral MMD, n=19 (18.4%); atherosclerotic cerebrovascular disease (ACVD), n=21 (20.4%); and control group, n=5 (4.9%). The intensity of CRABP-I was confirmed by western blotting and expressed as the median (25th-75th percentile). The differences in CRABP-I expression according to disease entity (unilateral MMD vs bilateral MMD vs ACVD), initial presenting symptoms (haemorrhage vs ischaemia) and postoperative haemodynamic change (vascular reserve in single photon emission CT and basal collateral vessels in digital subtraction angiography) were analysed.

RESULTS

CRABP-I intensities in bilateral MMD (1.45(0.86-2.52)) were significantly higher than in unilateral MMD (0.91(0.78-1.20)) (p=0.044) or ACVD (0.85(0.66-1.11)) (p=0.004). No significant differences were noted based on the initial presenting symptoms (p=0.687). CRABP-I was not associated with improvement in vascular reserve (p=0.327), but with decrease in basal collateral vessels (p=0.023) postoperatively.

CONCLUSIONS

Higher CRABP-I in the CSF can be associated with typical bilateral MMD pathogenesis in adults. Additionally, postoperative basal collateral change may be related to the degree of CRABP-I expression.

Indirect revascularization for nonmoyamoya intracranial arterial stenoses: clinical and angiographic outcomes

OBJECT

Symptomatic intracranial arterial stenoses have a high rate of recurrent stroke despite medical and endovascular treatments. The authors present clinical and angiographic quantitative outcomes of indirect revascularization for patients with symptomatic intracranial stenosis.

METHODS

Patients treated for symptomatic intracranial arterial stenosis by indirect revascularization were included. The patient population comprised those in whom medical management had failed and for whom endovascular therapy was unsuitable or had failed. Patients underwent encephaloduroarteriosynangiosis (EDAS) with or without bur holes. Preoperative and postoperative angiograms were evaluated for change in caliber of extracranial blood vessels (superficial temporal artery [STA] and middle meningeal artery [MMA]) and for evidence of neovascularization.

RESULTS

Thirteen patients underwent EDAS. Ischemic symptoms ceased within the follow-up period in all patients, returning in a delayed fashion in only 2. No other patients had recurrent TIAs or strokes after the initial postoperative period. Donor blood vessels increased in size relative to preoperative sizes in all but 1 case (average increase of 52% for proximal STA [p=0.01], 74% for midpoint of STA [p=0.01], and 84% for the MMA [p=0.02]). In addition, 8 of 11 patients demonstrated direct spontaneous anastomoses from extracranial to middle cerebral artery branches, and all patients demonstrated angiographic evidence of vascular blush and/or new branches from the STA and/or MMA.

CONCLUSIONS

Indirect revascularization appears to be a safe and effective method to improve blood flow to ischemic brain due to intracranial arterial stenosis. Neovascularization and enlargement of the branches of the ECA were observed in all patients and correlated with improvement in ischemic symptoms. Indirect revascularization is an option for patients in whom medical therapy has failed and who are not suitable for endovascular treatment.

Clinical and angiographic outcomes from indirect revascularization surgery for Moyamoya disease in adults and children: a review of 63 procedures

BACKGROUND

Several forms of indirect cerebral revascularization have been proposed to promote neovascularity to the ischemic brain.

OBJECTIVE

To present clinical and angiographic outcomes of indirect revascularization by encephaloduroarteriosynangiosis and burr holes for the treatment of Moyamoya disease in adults and children.

METHODS

Data from 63 hemispheres treated in 42 patients (average age, 30 years; 33 adults; 30 female patients; median follow-up, 14 months) were reviewed. In hemispheres with preoperative and postoperative (6- to 12-month) angiograms available, superficial temporal artery (STA) and middle meningeal artery (MMA) diameters were measured. Preoperative and postoperative corrected arterial sizes were compared.

RESULTS

Seven patients (17%) had transient ischemic attacks that resolved within 1 month of surgery. No patients suffered moyamoya-related hemorrhage after treatment. Two patients developed additional symptoms many years after surgery. In 18 hemispheres with preoperative and postoperative angiograms, there was an average postoperative increase in STA and MMA diameters of 51% (P = .003) and 49% (P = .002), respectively. Both children and adults displayed revascularization. Two patients did not demonstrate increased vessel size. STA blush and new branches and MMA blush and new branches were identified in 12, 14, 14, and 16 hemispheres, respectively. Angiographic blush was identified in 59% of frontal and 19% of parietal burr holes (P = .03). Surgical complications included 2 subdural hemorrhages requiring evacuation and 2 new ischemic deficits (1 transient).

CONCLUSION

Indirect revascularization by encephaloduroarteriosynangiosis and burr holes for moyamoya results in long-term resolution of ischemic and hemorrhagic manifestations in 95% of adults and children. The MMA appears to contribute significantly to the revascularization on follow-up angiograms with increased size and neovascularity comparable to that of the STA. Angiographically, parietal burr holes do not contribute as significantly as frontal burr holes.

Childhood and teenage stroke

OBJECTIVE

The purpose of this manuscript is to review the various etiologies and to discuss the therapeutic issues in childhood stroke.

METHODS

A PubMed search of literature pertaining to childhood stroke was conducted from 1983 to 2008 using specific key search words pertinent to cerebrovascular disorders in childhood.

RESULTS

The analysis of the multiple causes of childhood stroke including arterial ischemic strokes and cerebral venous thrombosis was presented. Current therapy and outcome data in childhood stroke are also discussed throughout the length of the article.

CONCLUSIONS

With increasing vigilance among physicians and improved neuroimaging modalities, the diagnosis of childhood stroke is now made earlier, with increasing frequency and greater accuracy. However, larger and well-controlled studies regarding the optimal management of childhood stroke in terms of the use of both antithrombotic drugs and anticoagulation are still needed in addition to longitudinal follow-up studies of children with stroke.

The role of indirect extracranial-intracranial bypass in the treatment of symptomatic intracranial atheroocclusive disease

Object

The optimal treatment of medically refractory intracranial atheroocclusive disease remains unclear. The EC-IC Bypass Study Investigators found that patients with internal carotid and middle cerebral artery (ICA and MCA) occlusion received no benefit from direct superficial temporal artery to MCA bypass, and that patients with ICA occlusion and MCA stenosis may have actually fared worse after surgery, perhaps in part due to flow reversal in critical perforator-bearing segments. Although the results of recent investigations have suggested that direct bypass may be beneficial in a subgroup of patients with hemodynamic failure secondary to unilateral ICA occlusion, similar data do not exist for patients with hemodynamic failure from other intracranial stenoocclusive diseases. Indirect bypass via encephaloduroarteriosynangiosis offers a surgical alternative that may avoid rapid flow reversal while providing additional flow to at-risk, distal vascular territories.

Methods

Twelve patients with medically resistant hemodynamic failure from intracranial atheroocclusive disease underwent indirect vascular bypass. Eight patients had ICA occlusion and coexistent MCA stenosis, 1 patient had tandem ICA stenoses and MCA stenosis, 1 patient had tandem ICA and MCA occlusion, 1 patient had ICA and posterior cerebral artery occlusion and an ischemic hemisphere supplied via a proximal superficial temporal artery branch, and 1 patient had poor donor arteries and severe medical comorbidities that precluded the use of general anesthesia. Patient evaluation included clinical assessment of neurological status, CT scanning, MR imaging, digital subtraction angiography, and transcranial Doppler ultrasonography with CO2 reactivity, or SPECT with acetazolamide challenge. Patient records were reviewed and patients were interviewed for outcome assessment, including transient ischemic attack (TIA), cerebral infarction, change in cerebral perfusion, graft patency, and functional level according to the modified Rankin scale. Kaplan-Meier cumulative failure curves for the primary end point of cerebral infarction were used to compare these patients to a control group of 81 patients derived from the literature who received medical management for severe symptomatic hemodynamic failure.

Results

Eleven patients underwent encephaloduroarteriosynangiosis and 1 patient received bur holes with dural and arachnoid incisions; the mean length of follow-up was 51.2 ± 40.1 months. Five patients had decreased perfusion on follow-up despite graft patency, and 10 patients suffered new infarctions or TIAs during the follow-up period. Five patients (42%) suffered infarctions within 1 year of surgery. A meta-analysis of 4 studies of patients with symptomatic ICA occlusion and severe hemodynamic failure who underwent medical treatment revealed a new infarction rate of 30% in the first year after entry into the study. There was no significant difference between patients with severe hemodynamic failure who underwent surgery and those in the medically treated control group (log-rank test, p = 0.179).

Conclusions

The authors found that indirect bypass does not promote adequate pial collateral artery development and appears to be of limited utility in patients with symptomatic ICA or MCA stenoocclusive disease and secondary hemodynamic failure. Rates of postoperative TIAs or cerebral infarctions after indirect bypass in this patient population do not differ from previous reports in patients who received medical management only.

Childhood moyamoya disease: quantitative evaluation of perfusion MR imaging--correlation with clinical outcome after revascularization surgery

PURPOSE

To evaluate whether perfusion magnetic resonance (MR) imaging can depict hemodynamic status after revascularization surgery and whether changes at perfusion MR imaging after revascularization surgery correspond with clinical outcome in moyamoya disease.

MATERIALS AND METHODS

An institutional review board approved this retrospective study; informed consent was waived. Pre- and postoperative perfusion MR imaging data in 67 children with moyamoya disease (mean age, 7.2 years; range, 2-13 years) were included. Regional time to peak (rTTP) and regional cerebral blood volume (rCBV) were calculated by adjusting cerebral time to peak (TTP) and cerebral blood volume (CBV) values by using cerebellar reference values. For quantitative regional analysis, pixel values were divided into five categories (>0, >2, >4, >6, and >8 seconds), and percentages of pixels in rTTP meeting these time conditions were calculated. Changes in the values after revascularization were calculated. Postoperative clinical outcomes were categorized as follows: 1 indicated excellent; 2, good; 3, fair; and 4, poor. Pre- and postoperative perfusion parameters were compared by using a paired t test; relationships between perfusion parameters and clinical outcomes were investigated by using one-way analysis of variance, with a significance level of .05.

RESULTS

rTTP, rCBV, and percentage of pixels of rTTP decreased significantly after revascularization surgery. Pre- and postoperative rTTP were significantly different for the clinical outcome categories. Change in rTTP and change in percentage of pixels of rTTP (>0 seconds to >6 seconds) were significantly different for the clinical outcome categories.

CONCLUSION

TTP and CBV perfusion maps can depict hemodynamic status after revascularization surgery in moyamoya disease. Furthermore, changes in TTP perfusion maps after revascularization surgery correspond with clinical outcome in patients with moyamoya disease.

Moyamoya disease: a clinical spectrum, literature review and case series from a tertiary care hospital in Pakistan

Background

Moyamoya is a rare cerebrovascular disease of unknown etiology. The data on moyamoya disease from Pakistan is sparse. We report a case series of 13 patients who presented with moyamoya disease to a tertiary care hospital in Pakistan with a national referral base.

Methods

We conducted a retrospective review of thirteen patients who presented to The Aga Khan University and diagnosed with "Moyamoya Disease" during the period 1988 – 2006. These patients were identified from existing hospital database via ICD-9 codes. A predesigned questionnaire containing information about clinical presentation, management and neuroimaging was administered to all identified patients.

Results

There were seven males and six females. Mean age at presentation was 16.5 years and a female predominance was found in the pediatric age group (n = 10, 71.4%). Stroke (n = 11, 84.2%) was the most common presentation with motor deficit being the universal cortical symptom. Fever was a common symptom in the lower age groups (n = 4, 51.7%). Cerebral Angiography and Magnetic Resonance Angiography showed bilateral involvement of the vessels in eleven patients while unilateral in two. Subarachnoid and interventricular haemorrhage appeared in 2(15.4%) adults. Twelve (92.3%) patients were discharged as independent with minor deficits regardless of therapeutic modality. Only three (23.0%) patients underwent surgery whereas the remaining were managed conservatively.

Conclusion

Physicians when dealing with childhood strokes and characteristic deficits in adult population should consider Moyamoya disease.

Expression of vascular endothelial growth factor in dura mater of patients with moyamoya disease

Vascular endothelial growth factor (VEGF) has been found to be involved in vasculogenesis in different intracranial lesions. We investigated meningeal cellularity and VEGF expression in dura mater of patients with and without moyamoya disease. Nine dural specimens from nine cerebral hemispheres of seven patients with moyamoya disease and four control dural specimens from four non-moyamoya patients were collected during surgery and investigated. Dural specimens were immunohistochemically stained with VEGF antibody, and then meningeal cellularity and VEGF expression in dural tissue were analyzed. The mean+/-standard error (SE) of total number of meningeal cells (meningeal cellularity) in dural tissue was 21.5+/-3.0 in the moyamoya disease patients, whereas it was 2.7+/-0.7 in control patients. The mean+/-SE of VEGF expression was 51.1+/-4.9% in the moyamoya disease patients, whereas it was 13.8+/-5.9% in control patients. The meningeal cellularity and VEGF expression were statistically significantly higher in the moyamoya group in comparison to control group (p<0.0001). Meningeal cellularity and VEGF expression are significantly increased in dura mater of the patients with moyamoya disease.

Surgical results in pediatric moyamoya disease: Angiographic revascularization and the clinical results

OBJECTIVE

We retrospectively reviewed the pediatric patients with moyamoya disease (MMD) who underwent bypass surgery at our institution to compare the surgical results according to the surgical procedures.

PATIENTS AND METHODS

There were 24 total patients (age range: 2-15 years; mean age: 8.2 years). Twelve patients underwent encephalo-duro-arterio-synangiosis (EDAS) on 16 sides, 5 patients underwent encephalo-duro-arterio-myo-synangiosis (EDAMS) on 8 sides and 7 patients underwent combined superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis with EDAMS (STA-MCA-EDAMS) on 12 sides. The postoperative results were evaluated between 4 months and 5 years following surgery in terms of the angiographic revascularization and the clinical outcome.

RESULTS

EDAMS, regardless of the combined STA-MCA anastomosis, was significantly effective for achieving a good extent of the postoperative angiographic revascularization as compared with simple EDAS (P<0.05). STA-MCA-EDAMS tended to be better with respective to the relief of preoperative ischemic symptoms as compared with simple EDAS, although there was no significant statistical difference.

CONCLUSION

These results suggest that EDAMS with or without the combination of STA-MCA anastomosis was very useful for the formation of collateral circulation in comparison with simple EDAS for treating the pediatric patients with MMD, although these findings were not well correlated with the clinical outcomes.

Primary Percutaneous Transluminal Angioplasty for Early Moyamoya Disease

Moyamoya disease is a progressive steno-oclusive arteriopathy of the circle of Willis that manifests on cerebral angiography with a characteristic net of vessels at the base of the brain representing collateralization. Described initially in Japan where children present with cerebral ischemia and adults with hemorrhagic stroke, it was recognized to have a more benign course in the United States, mainly causing cerebral ischemic events in young adults. Medical treatment is not intended to stop the progression of the disease and surgery is not exempt of risks. We present a patient with early moyamoya disease in the United States in whom primary transluminal angioplasty, a less invasive procedure, was performed to treat the stenotic arteriopathy with good immediate and sustained clinical and angiographic results, without evidence of restenosis at the site of angioplasty 2 years later.

Steal phenomenon through the anterior communicating artery in Moyamoya disease

Branch occlusion of the anterior cerebral artery (ACA) is regarded as a part of Moyamoya disease. The purpose of this study is to define the ACA steal phenomenon (SP) in Moyamoya disease and to evaluate temoporal changes according to the disease progression. From 139 Moyamoya patients we defined ACASP as narrowing of the ipsilateral A1-2 junction while preserving the anterior communicating artery and supplying the contralateral ACA cortical branches with the development of leptomeningeal collaterals by the ipsilateral middle cerebral artery into the hypoperfused ipsilateral ACA territory. Direction of the steal related to the stage in both hemispheres by Suzuki classification was statistically analyzed using the binomial test based on binomial distribution. Follow-ups of ACASP were evaluated in five patients. We identified ACASP in 13 (9%) patients (male:female=7:6, mean age 18 years, range: 2-58 years) of the 139 study patients. The presenting pattern was ischemic in 12 and hemorrhagic in one. The direction of SP occurred from the hemisphere in the lower to the higher stage of Suzuki classification (two-tail P value=0.0002). After revascularization surgery, ACASP disappeared or diminished. ACASP may occur in bilaterally different stages of Moyamoya disease as a transient self-adaptive process. It regresses after revascularization surgery.

Long term outcome in children with Moyamoya disease: experience with 16 patients

We present our experience with 16 children with Moyamoya disease/variant diagnosed at the Royal Alexandra Hospital for Children, Westmead, Sydney, Australia in the period between January 1982 and March 2004. Thirteen of these patients had one of the different revascularisation procedures. We reviewed the modes of presentation and the long-term outcome in these children. In our series the functional outcome was related to the functional status at presentation and was not related to the type of surgical procedure or age at presentation. We believe this is the largest reported series of Moyamoya disease/variant in Australia.

Surgical management of moyamoya syndrome

Moyamoya syndrome, a vasculopathy characterized by chronic progressive stenosis at the apices of the intracranial internal carotid arteries, is an increasingly recognized entity which is associated with cerebral ischemia. Diagnosis is made on the basis of clinical and radiographic findings, including a characteristic stenosis of the internal carotid arteries in conjunction with abundant collateral vessel development. Adult moyamoya patients often present with hemorrhage, leading to rapid diagnosis. In contrast, children usually present with transient ischemic attacks or strokes, which may prove more difficult to diagnose because of patient's inadequate verbal and other skills, leading to delayed recognition of the underlying moyamoya. The progression of disease can be slow, with rare, intermittent events, or it can be fulminant, with rapid neurologic decline. However, regardless of the course, it is apparent that moyamoya syndrome, both in terms of arteriopathy and clinical symptoms, inevitably progresses in untreated patients. Surgery is generally recommended for the treatment of patients with recurrent or progressive cerebral ischemic events and associated reduced cerebral perfusion reserve. Many different operative techniques have been described, all with the main goal of preventing further ischemic injury by increasing collateral blood flow to hypoperfused areas of the cortex, using the external carotid circulation as a donor supply. This article discusses the various treatment approaches, with an emphasis on the use of pial synangiosis, a method of indirect revascularization. The use of pial synangiosis is a safe, effective, and durable method of cerebral revascularization in moyamoya syndrome and should be considered as a primary treatment for moyamoya, especially in the pediatric population.

Magnetic resonance angiography evaluation of external carotid artery tributaries in moyamoya disease

BACKGROUND AND PURPOSE

High-resolution magnetic resonance (MR) image has been introduced to diagnose and follow-up moyamoya disease and visualized moyamoya vessels and internal carotid artery stenosis. This study was performed to assess the utility of MR angiography (MRA) for the evaluation of anastomotic channels through the external carotid artery (ECA) in moyamoya disease patients.

METHODS

Twenty patients with moyamoya disease were reviewed. The cortical anastomosis and superficial temporal artery (STA), middle meningeal artery, and deep temporal artery by MRA were evaluated and were compared with those by digital subtraction angiography if obtained. Fifteen patients (24 hemispheres) underwent bypass surgery, including encephaloduroarteriosynangiosis in 14 hemispheres and STA-middle cerebral artery anastomosis with encephalomyosinangiosis in 10 hemispheres. Five patients did not undergo any surgery.

RESULTS

MRA could show these vessels and the patency of anastomosis formed by the surgery and also showed naturally formed anastomosis and ECA tributaries in the patients who did not undergo any surgery.

CONCLUSION

MRA provides useful information for follow-up evaluation on the development of the ECA system in moyamoya disease.

Combined encephaloduroarteriosynangiosis and bifrontal encephalogaleo(periosteal)synangiosis in pediatric moyamoya disease

OBJECTIVE

We compared the surgical results of simple encephaloduroarteriosynangiosis (EDAS) and EDAS with bifrontal encephalogaleo(periosteal)synangiosis for the treatment of pediatric moyamoya disease.

METHODS

Data for 159 children (up to 15 yr of age, 76 boys and 83 girls) who underwent indirect revascularization procedures for the treatment of moyamoya disease between 1987 and 1998 were retrospectively reviewed. Group A patients underwent simple EDAS (n = 67). Group B patients underwent EDAS with bifrontal encephalogaleo(periosteal)synangiosis (n = 92). The surgical results for each group were compared, in terms of clinical outcomes, neuroimaging changes, extent of revascularization evident on angiograms, and hemodynamic changes evident on single-photon emission computed tomographic scans. The average follow-up periods were 45 months for Group A and 22 months for Group B.

RESULTS

The overall clinical outcomes and neuroimaging changes tended to be better for Group B. In terms of single-photon emission computed tomographic changes of the whole brain after surgery, Group B patients exhibited more favorable outcomes than did Group A patients (62 versus 36%, P = 0.003). The surgical results for the anterior cerebral artery territory were significantly better for Group B than for Group A, with respect to outcomes of anterior cerebral artery symptoms (81 versus 40%, P = 0.015), revascularization on angiograms (79 versus 16%, P < 0.001), and hemodynamic changes on single-photon emission computed tomographic scans (70 versus 52%, P = 0.002). The incidences of postoperative infarctions were not significantly different between the two groups.

CONCLUSION

EDAS with bifrontal encephalogaleo(periosteal)synangiosis is a more effective surgical modality for the treatment of pediatric moyamoya disease, compared with simple EDAS, because it covers both the middle cerebral artery and anterior cerebral artery territories of the brain.

High-resolution turbo magnetic resonance angiography for diagnosis of Moyamoya disease

BACKGROUND AND PURPOSE

High-resolution turbo MR angiography with zero-filling interpolation (ZFI) technique is a new vascular imaging method with reduced scan time. The purpose of the present study was to evaluate high-resolution turbo MR angiography for the diagnosis and assessment of moyamoya disease.

METHODS

Forty-six patients suspected of having moyamoya disease were examined with high-resolution turbo MR angiography with the ZFI technique, MRI, and conventional angiography. Moyamoya disease was diagnosed in 42 of these patients. Blind, separate interpretation of the images was performed.

RESULTS

High-resolution turbo MR angiography and MRI accurately evaluated 349 (95%) and 325 (88%) of 368 arteries, respectively, but the degree of stenosis was overestimated in the other arteries. MR angiography and MRI depicted basal cerebral moyamoya vessels in 82 (98%) and 82 (98%) of 84 hemispheres, respectively. MR angiography also depicted leptomeningeal and transdural collateral vessels in 51 (100%) of 51 hemispheres and in 38 (88%) of 43 hemispheres, respectively. The sensitivity and specificity of high-resolution turbo MR angiography for the diagnosis of moyamoya disease were 98% and 100%, respectively.

CONCLUSIONS

High-resolution turbo MR angiography in reduced scan time is highly accurate in the assessment of both steno-occlusive lesions and collateral vessels in moyamoya disease, thus providing a highly accurate (98%) diagnosis and assessment of moyamoya disease.

Moyamoya syndrome: post cranial irradiation of pineal gland tumor

SUMMARY

A right-handed eight-year-old boy, with headache, vomiting and positive parinaud's sign was diagnosed as having a pineal gland tumor which histopathological section from surgical biopsy revealed to be a germinoma. The patient underwent ventriculoperitoneal shunt for obstructive hydrocephalus. Thereafter, he received cranial irradiation as definitive treatment. He was well and went back to school until five years later he developed a transient ischemic attack. Cranial magnetic resonance imaging showed a complete cure of the pineal tumor without any other specific abnormality. Eight months later he had an episode of stroke which was demonstrated by cranial computed tomography as acute left cerebral infarction in the middle cerebral artery territory. Cerebral angiography showed Moyamoya syndrome.

Stroke in Children

Identification and treatment of the underlying risk factors for stroke reduce the potential for additional strokes; therefore, a thorough search for treatable risk factors is justified. Because some risk factors can have a cumulative effect, even children with known risk factors for stroke sometimes need to be evaluated for other conditions. Cerebral angiography is often helpful; I recommend angiography in any child with an unexplained infarction or hemorrhage. Angiography is especially important in children with intraparenchymal hemorrhage because more than one third of such children will prove to have some type of potentially treatable congenital vascular anomaly such as an arteriovenous malformation (AVM) or aneurysm. The evidence that periodic blood transfusion effectively prevents cerebral infarction due to sickle cell disease is compelling. Transfusions apparently must be continued indefinitely to maintain the reduction of stroke risk, and without iron chelation, chronic transfusion eventually results in severe iron toxicity and, most likely, death, so the decision to begin transfusion is not an easy one. Measurement of the time-averaged mean flow velocity in the large cerebral vessels with transcranial Doppler (TCD) is highly predictive of stroke risk in these children, enough to justify its routine use in screening patients with sickle cell disease for stroke risk. I believe that patients with sickle cell disease should be offered chronic transfusion after an initial large-vessel stroke or when the TCD results suggest a high risk of stroke. The family must be made aware of the serious complications of chronic transfusion and the importance of complying with chelation once it is started. There are no controlled clinical trials to guide the use of anticoagulants, antiplatelet agents, or thrombolytic agents in children, although these drugs are being used more and more often in pediatric patients. For the most part, our approach has been adapted from our experience with adults. Heparin followed by warfarin is often used for sinovenous thrombosis and for arterial dissection. I also suggest long-term anticoagulation for children with coagulopathy or a high risk of embolism due to congenital or acquired cardiac disease. It is reasonable to use a thrombolytic agent in children with an acute infarction; because few children present soon enough after the onset of symptoms, however, thrombolysis is infrequently used. Aspirin is used more than other antiplatelet agents in children, largely because of years of experience with aspirin and the lack of evidence that other agents are more effective. Despite its frequent use, there are no unequivocal indications for the use of aspirin in children. Aspirin is often started empirically in children suspected to be at substantial risk for additional ischemic stroke but whose risk is ill defined, an approach not too dissimilar from that often used in adult patients. Although the risk of Reye's syndrome in a child taking daily aspirin for stroke prevention is a common concern, I know of no published examples of children who developed Reye's syndrome while taking prophylactic aspirin. This apparently low risk must be weighed against the often-considerable risk of ischemic stroke that could be reduced by the use of daily aspirin. In situations such as vasculopathy or infarction of unknown cause, the small risk of Reye's syndrome seems acceptable.

Renal artery lesions in patients with moyamoya disease: angiographic findings

BACKGROUND AND PURPOSE

Renal artery lesions in moyamoya disease have been described sporadically in several case reports. The purpose of this study is to evaluate the angiographic findings of renal artery lesions in moyamoya disease and to determine the prevalence of renal artery lesions in patients with moyamoya disease.

METHODS

Eighty-six consecutive patients with idiopathic moyamoya disease were prospectively examined with both cerebral angiography and abdominal aortography. The findings of abdominal aortography were reviewed for the presence and appearance of renal artery lesions and compared with the clinical data and cerebral angiographic findings.

RESULTS

Of 86 patients with idiopathic moyamoya disease, 7 patients (8%) were found to have renal artery lesions. Six patients (7%) had stenosis in the renal artery, and 1 patient (1%) had a small saccular aneurysm in the renal artery. Two patients (2%) with a marked renal artery stenosis presented with renovascular hypertension, which resulted in an intraventricular hemorrhage in 1 patient. Furthermore, the renal artery stenosis in the 2 patients with renovascular hypertension was successfully treated with percutaneous transluminal angioplasty. There was no significant correlation between the presence of renal artery lesions and cerebral angiographic findings.

CONCLUSIONS

Seven (8%) of 86 patients with moyamoya disease showed renal artery lesions, including 6 stenoses (7%) and 1 aneurysm (1%). Renal artery lesions are a clinically relevant systemic manifestation in patients with moyamoya disease.

MR angiography of moyamoya disease before and after encephaloduroarteriosynangiosis

OBJECTIVE

Our purpose was to evaluate the usefulness of MR angiography in revealing moyamoya disease before and after encephaloduroarteriosynangiosis.

SUBJECTS AND METHODS

Twenty-six patients (51 hemispheres) with angiographically confirmed moyamoya disease who underwent encephaloduroarteriosynangiosis were included in the study. Findings on preoperative MR angiography were compared with those on conventional angiography. Postoperative neurologic status was categorized as poor, fair, good, or excellent. Postoperative MR angiography was examined for the appearance of the superficial temporal artery, changes in moyamoya vessels, and transdural collateral vessels into the middle cerebral artery territory.

RESULTS

Preoperative MR angiography revealed moyamoya disease in all patients (diagnostic accuracy, 100%). MR angiography correctly depicted the degree of internal carotid artery stenosis in 37 arteries (73%), moyamoya vessels in 33 hemispheres (65%), and the degree of stenosis in the middle, anterior, and posterior cerebral arteries in 125 (82%) of 153 arteries. After surgery, 39 hemispheres showed an excellent outcome, eight showed a good outcome, two a fair outcome, and two a poor outcome. On postoperative MR angiography, vascular supply to the middle cerebral artery territory via transdural collateral vessels increased in 28 hemispheres (55%) and decreased in four (8%). The size of the superficial temporal artery increased in 41 (80%) of 51 hemispheres. The extent of moyamoya vessels decreased in 27 hemispheres (53%) after surgery.

CONCLUSION

MR angiography can show the changes in the superficial temporal artery and development of transdural collateral vessels after encephaloduroarteriosynangiosis. Because MR angiography is noninvasive, it is valuable for evaluating postoperative changes.

Moyamoya disease: evaluation with diffusion-weighted and perfusion echo-planar MR imaging

PURPOSE

To determine the clinical efficacy of diffusion-weighted and perfusion echo-planar magnetic resonance (MR) imaging in the evaluation of moyamoya disease.

MATERIALS AND METHODS

Seventeen patients with moyamoya disease were examined prospectively with diffusion-weighted and perfusion echo-planar MR imaging and conventional angiography. The change in the effective transverse relaxation rate (delta R2*) peak value, delta R2* peak time, and delta R2* integral were calculated to assess regional cerebral perfusion. The MR images were compared with angiographic images.

RESULTS

Of the 34 posterior cerebral arteries (PCAs) of the 17 patients, 14 PCAs (41%) in 11 patients showed stenosis or occlusion. The delta R2* peak value ratio in the cerebral hemispheres decreased significantly, and the delta R2* peak time ratio increased significantly, with PCA stenosis and occlusion. However, no correlation was apparent between perfusion and extent of the stenotic or occlusive lesions of the internal carotid artery bifurcation. The frequency of cerebral infarctions was significantly increased in patients with stenotic or occlusive PCA lesions. For three acute infarctions, a decrease in the apparent diffusion coefficient was significantly correlated with a decrease in the delta R2* peak value, an increase in the delta R2* peak time, and a decrease in the delta R2* integral.

CONCLUSION

Regional cerebral perfusion in moyamoya disease is decreased and delayed with PCA stenosis, with greater decrease and delay with PCA occlusion. Diffusion-weighted and perfusion imaging are useful for evaluating cerebral ischemia in moyamoya disease.

Clinical features of moyamoya disease in the United States

BACKGROUND AND PURPOSE

We report the clinical features and longitudinal outcome of the largest cohort of patients with moyamoya disease described from a single institution in the western hemisphere. Moyamoya disease in Asia usually presents with ischemic stroke in children and intracranial hemorrhage in adults.

METHODS

Our study population included all patients with moyamoya disease evaluated at a university hospital in Houston, Texas from 1985 through 1995 (n = 35). We used Kaplan-Meier methods to estimate individual and hemispheric stroke risk by treatment status (medical versus surgical). Predictors of neurological outcome were assessed.

RESULTS

The ethnic background of our patients was representative of the general population in Texas. The mean age at diagnosis was 32 years (range, 6 to 59 years). Ischemic stroke or transient ischemic attack was the predominant initial symptom in both adults and children. Of the 6 patients with intracranial hemorrhage, 5 had an intraventricular site of hemorrhage. The crude stroke recurrence rate was 10.3% per year in 116 patient-years of follow-up. Twenty patients underwent surgical revascularization, the most common procedure being encephaloduroarteriosynangiosis. The 5-year risk of ipsilateral stroke after synangiosis was 15%, compared with 20% for medical treatment and 22% overall for surgery.

CONCLUSIONS

Our observations indicate that moyamoya disease may have a different clinical expression in the United States than in Asia, and may demonstrate a trend toward a lower stroke recurrence rate and better functional outcome after synangiosis.

Long-term intelligence outcome of post-encephalo-duro-arterio-synangiosis childhood moyamoya patients

Long term post-encephalo-duro-arterio-synangiosis (EDAS) intelligence quotient (IQ) evaluated by Wechsler tests stays around the normal range (mean full intelligence quotient (FIQ), verbal intelligence quotient (VIQ) and performance intelligence quotient (PIQ) at 100.0 +/- 155, 100.0 +/- 15.7 and 100.2 +/- 163, respectively) at more than 9.5 years after the operation, provided that the patient has FIQ above 70 pre-operatively. This fact encourages us to employ operative treatment for this difficult disease in which intelligence deterioration has been reported to be a common occurrence.

Natural history of moyamoya disease: comparison of activity of daily living in surgery and non surgery groups

The present study was undertaken to reach a clearer understanding of the natural history of Moyamoya disease. Follow-up studies were performed in 88 patients with Moyamoya disease. They were divided into the ischemia group and the hemorrhage group. The activity of daily living (ADL) of each groups were followed up and compared between those who were surgically treated and conservatively managed. Ischemic manifestations were more common in the younger children and tended to be recurrent, whereas hemorrhagic manifestations were more common in the adults. Follow-up duration of the 36 patients, who were surgically treated, ranged from 6 to 86.4 months (mean: 28.8 months). During the follow-up period, ADL was improved in 17 of 31 ischemic Moyamoya patients (55%); the condition was unchanged in nine (29%); and aggravated in five (16%). Follow-up duration of the 52 patients who were managed without surgery ranged from 12 to 216 months (mean: 67.2 months). In 35 patients of the ischemia group, ADL was aggravated in 49% and improved in only 26% during the follow-up period. However, ADL was aggravated in 12% of 17 hemorrhagic patients, but improved in 53%. Our result suggest that indirect revascularization procedures are effective for prevention of recurrent ischemic attacks which is common in pediatric patients. However, the effectiveness of indirect revascularization for hemorrhagic Moyamoya disease is not clear and requires extended follow-up study.

Indirect revascularization for moyamoya disease: is there a beneficial effect for adult patients?

BACKGROUND

It is generally accepted that excellent development of collateral circulation can be achieved through indirect nonanastomotic bypass procedures for pediatric patients with moyamoya disease. However, there are no definitive conclusions about the effect of indirect revascularization for adult patients. To clarify the value of indirect bypass surgery for adult moyamoya disease, we have analyzed their follow-up angiographic results in comparison with those of the pediatric patients.

METHODS

Between 1989 and 1993, 23 patients underwent combined direct and indirect bypass surgery. They consisted of 16 adults (mean age, 35; range, 20-59) and seven children (mean age, 10; range, 3-16). The main symptoms were those due to cerebral ischemia in all but 1 of 23 patients. Preoperative cerebral blood flow studies showed all patients to have decreased vascular reserve (misery perfusion). Postoperative follow-up angiography was done in all patients at a median of 6 months after the surgery.

RESULTS

All pediatric patients showed good or moderate development of collaterals through the indirect bypass. Among the adult group, seven patients aged 20 to 29 had angiographic results similar to those of the pediatric group . On the other hand, nine patients older than 30 had results contrary to those of pediatric patients: (1) the degree of indirect revascularization declined to moderate or poor grades (especially in patients older than 40) and (2) the degree of direct bypass filling improved to high or medium grades.

CONCLUSIONS

The results suggest that advancing age apparently affects the development of collateral formation through the indirect bypass. Consequently, direct bypass is thought to be the main treatment option for patients older than 40.

Moyamoya disease: diagnostic accuracy of MRI

Our purpose was to evaluate the diagnostic accuracy of MRI in moyamoya disease. We studied 30 patients with this disease, comparing MRI and angiographic findings. The diagnostic value of MRI was evaluated for occlusive lesions, collateral vessels, and parenchymal lesions. In all patients bilateral occlusion or stenosis of the supraclinoid internal carotid artery and proximal anterior and middle cerebral arteries was clearly shown by MRI, and staging of the extent of occlusion agreed with angiographic staging in 44 (73%) of 60 arteries. MRI, particularly coronal images, clearly showed basal cerebral moyamoya vessels in 54 hemispheres, and 45 of a total of 71 large leptomeningeal and transdural collateral vessels were identified. MRI also showed parenchymal lesions in 48 (80%) hemispheres, and the extent of occlusion in the anterior and posterior circulations respectively correlated with white matter and cortical and/or subcortical infarcts.

Surgically induced angiogenesis to compensate for hemodynamic cerebral ischemia

BACKGROUND AND PURPOSE

The ischemic brain may stimulate angiogenesis to compensate for impaired circulation. We examined the conditions promoting such angiogenesis to provide the basis for surgical treatment.

METHODS

The degree of cerebral hemodynamic stress was studied in patients with moyamoya disease using the stable xenon-enhanced computed tomographic acetazolamide tolerance test and positron emission tomography. Patients were subjected to surgery in which scalp arteries were placed on the cerebral cortex without vessel-to-vessel anastomosis. Formation of the newly vascularized collateral network connecting the implanted artery to cortical arteries was assessed angiographically 12 to 17 months after surgery.

RESULTS

Preoperative average resting cerebral blood flow for cortex that developed revascularization of cortical arteries was not significantly different from that for cortex that did not. However, cortex that developed revascularization had an average preoperative increase of blood flow by acetazolamide treatment of -3.29 +/- 4.6 mL/min per 100 cm3 (n = 20), which was significantly less (P = .0034) than that of cortex that did not show revascularization (20.7 +/- 4.3 mL/min per 100 cm3; n = 9). Good revascularization developed when the cortex showed increase of blood flow by acetazolamide treatment of less than 0 (steal phenomenon). Preoperative positron emission tomography data indicated that revascularization developed when the cortex was under "misery perfusion." Postoperative hemodynamics were ameliorated by revascularization.

CONCLUSIONS

Angiogenesis to connect the implanted scalp arteries to the cerebral cortical arteries was selectively initiated when ischemia of hemodynamic origin existed.