Incidence and Clinical Features of Disease Progression in Adult Moyamoya Disease

Contralateral cerebral hemodynamic changes after unilateral direct revascularization in patients with moyamoya disease

Direct revascularization has been used successfully to prevent strokes by improving regional cerebral blood flow (rCBF) to the affected hemisphere faster in patients with moyamoya disease (MMD). Since most literatures have focused on the rCBF changes of operative hemisphere, we evaluated the hemodynamics of nonoperative side by xenon-enhanced computed tomography (Xe-CT) and acetazolamide challenge test in patients with MMD during a short time follow-up. Fifteen MMD patients with unilateral ischemic presentations who received direct revascularization on the symptomatic hemispheres with complete hemodynamic evaluations by Xe-CT and acetazolamide challenge test were enrolled. Hemodynamic evaluations were performed 1, 3, and 6 months, postoperatively. The postoperative rCBF and cerebral vascular reserve (CVR) were recorded and correlated with clinical outcome. Angiography was performed if the patient had neurological deterioration or deficits. The average follow-up time was 8.5±3.5 months. Three months after the ipsilateral direct revascularization, the CVR of nonoperative hemispheres (25.8±8.1%) began to decrease significantly (P=0.003). Six months later, the rCBF showed a downward trend in nonoperative hemispheres (47.4±8.0 ml·100 g(-1) min(-1)) than the preoperative status, but the difference was not significant (P=0.053). Three patients presented with decreased rCBF and impaired CVR in the nonoperative hemispheres. Among them, two patients were symptomatic. Unilateral direct revascularization in symptomatic hemisphere for MMD patient could induce CVR impaired in primary asymptomatic hemisphere during the short term after the surgery. Therefore, critical follow-up, especially the hemodynamic follow-up in the asymptomatic hemispheres should be performed in patients with MMD.

Moyamoya disease as a possible cause of neurological impairment following liver transplantation for Wilson's disease

In Wilson's disease, liver transplantation can constitute the only option for patients presenting with fulminant hepatic failure or decompensated liver disease unresponsive to drug therapy. We report the case of a 29-year-old woman receiving a liver transplant for end-stage Wilson's disease who developed neurological complications after transplantation. After an accurate evaluation of possible differential causes of neurological complications developing as the result of liver transplantation, moyamoya disease was diagnosed. Moyamoya disease is a rare cerebrovascular disease of unknown etiology. However, data exist supporting a possible role for some immunosuppressive regimens in determining the peculiar vascular alterations observed in moyamoya disease. To the best of our knowledge, the association with post-transplantation state for Wilson's disease has not been previously described.

Middle cerebral artery stenosis associated with moyamoya pattern collateralization

Background and Purpose: Moyamoya disease is a well described phenomenon. This pattern of collateralization associated with isolated middle cerebral artery stenosis and the natural history of this entity have not been well described. Methods: Cerebral angiograms and CT angiograms performed between August 2004 and August of 2006 demonstrating moyamoya collateralization were retrospectively reviewed. All cases of middle cerebral artery stenosis associated with a rete pattern of collateralization were included in this series. Demographic, clinical, and angiographic data were obtained. Results: There were three cases of middle cerebral artery stenosis associated with a moyamoya pattern of collateralization. The average age of the patients was 36-years old, 2 were male, and all were Caucasian. All patients presented with ischemic symptoms. The average degree of stenosis was 91%. No stenosis was seen in the supraclinoid internal carotid arteries or elsewhere in the intracranial vasculature. Conclusion: We describe an unusual pattern of anastomosis associated with isolated severe middle cerebral artery stenosis or occlusion in Caucasians.

Paradoxical association of moyamoya syndrome with large middle cerebral artery aneurysm and subarachnoid hemorrhage. Case report

A 69-year-old woman was admitted to our hospital because of fluctuating dysarthria during the past 2 months. Magnetic resonance imaging revealed old cerebral infarction of the left cerebral hemisphere with acute subarachnoid hemorrhage in the left sylvian fissure. Cerebral angiography showed a large saccular aneurysm, 14 mm in diameter, at the bifurcation of the left middle cerebral artery (MCA) in association with moyamoya vasculopathy with atherosclerosis, including steno-occlusive changes at the bilateral terminal internal carotid arteries and abnormal net-like vessels at the base of the brain. She underwent microsurgical neck clipping of the large aneurysm followed by superficial temporal artery-MCA anastomosis without complication. Intraoperative findings showed no evidence of aneurysm rupture, suggesting that the subarachnoid hemorrhage was due to the intrinsic pathology of moyamoya vasculopathy. The postoperative course was uneventful, and the patient was discharged without neurological deficit. Association of moyamoya syndrome with large MCA aneurysm is extremely rare, and formation of large aneurysm at the vascular territory of an occluded vessel is apparently unique.

Genetic and clinical characteristics of Moyamoya disease in Europeans

The European form of Moyamoya disease clearly differs from the Asian form. Clinically the timing of vasculopathy onset and a lower rate of hemorrhage are striking as compared to the Asian Moyamoya disease.Single nucleotide polymorphisms that play a role in atherosclerosis, vascular growth and transformation processes have been found to be associated with the European form. Candidate gene associations found in Asian patients could not be replicated in European patients.To elucidate the characteristics, we describe the clinical features as well as the genetic findings that we have found in our combined cohorts of European patients.

Moyamoya disease in which pentazocine treatment caused cerebral infarction

A 37-year-old man was admitted to hospital for treatment of perineum damage and haematoma in the scrotum. His consciousness deteriorated after two intramuscular injections of pentazocine 15 mg. Faint low signals in the left putamin to frontal island and frontal lobe and obnubilation of the corticomedullary junction were apparent on head CT, which led to suspicion of cerebral infarction. MR angiography showed bilateral obstruction of the middle cerebral artery and moyamoya disease was diagnosed. Treatment with edaravone, argatroban and heparin was ineffective for opening the middle cerebral artery and serious after effects occurred. This case suggests that cerebrovascular accident should be suspected in a young patient with disturbance of consciousness but stable breathing and circulation, particularly if previous drug treatment has affected brain circulation. Moyamoya disease should be suspected based on medical or family history. In such a case, MR angiography is required for early diagnosis to facilitate treatment by re-establishment of blood circulation.

Pediatric moyamoya disease: An analysis of 410 consecutive cases

OBJECTIVE

Moyamoya disease (MMD) is a cerebrovascular occlusive disease of the bilateral internal carotid arteries that causes a compensatory abnormal vascular network at the base of brain. The rare incidence and various surgical techniques applied have limited the clinical research on MMD.

METHODS

We conducted a retrospective analysis of the surgical outcome of 410 pediatric MMD patients. All patients were treated in a relatively uniform scheme at a single institution. The surgical procedures consisted of bilateral encephaloduroarteriosynangiosis augmented by bifrontal encephalogaleo-/periosteal synangiosis. Logistic regression analyses were applied to reveal the prognostic factors for surgical outcome.

RESULTS

The overall clinical outcome was excellent in 66%, good in 15%, fair in 15%, and poor in 4% of the patients. Therefore, 81% of the patients had a favorable clinical outcome (excellent and good). Multivariate analyses revealed that infarction on presentation was associated with unfavorable clinical outcome (odds ratio [OR], 2.85; 95% confidence interval [CI], 1.49-5.46; p < 0.01) and decreased vascular reserve only on single-photon emission computerized tomography (OR, 0.07; 95% CI, 0.01-0.52; p < 0.01), with favorable clinical outcome.

INTERPRETATION

Our results indicate that an early diagnosis and active intervention before establishment of irreversible hemodynamic change are essential to achieve a favorable clinical outcome in children with MMD.

Novel Bypass Surgery for Moyamoya Disease Using Pericranial Flap: Its Impacts on Cerebral Hemodynamics and Long-term Outcome

OBJECTIVE

We reviewed our 11-year experience with a novel bypass procedure, superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-arterio-pericranio-synangiosis (EDMAPS), for moyamoya disease regarding cerebral hemodynamics and long-term outcome.

METHODS

This prospective study included 75 patients with moyamoya disease, including 28 children and 47 adults. We performed STA-MCA anastomosis and EDMAPS on 123 hemispheres of 75 patients. In addition to conventional STA-MCA anastomosis and indirect bypass for the MCA territory, the medial frontal lobe was revascularized using the frontal pericranial flap through medial frontal craniotomy. Surgical results were analyzed with magnetic resonance imaging, cerebral angiography, and single-photon emission computed tomography/positron emission tomography.

RESULTS

Overall incidences of mortality and morbidity were 0% and 5.7%, respectively. The annual risk of cerebrovascular events during the follow-up periods was very low: 0% in pediatric patients and 0.4% in adults over approximately 67 months. Postoperative cerebral angiography showed that the pericranial flap functioned well as donor tissue for indirect bypass, especially in pediatric patients. Follow-up single-photon emission computed tomography/positron emission tomography studies revealed that cerebral blood flow and its reactivity to acetazolamide markedly improved in both the MCA and anterior cerebral artery territories.

CONCLUSION

These findings strongly suggest that STA-MCA anastomosis and EDMAPS using a frontal pericranial flap is a safe and effective surgical procedure to further improve the long-term prognosis in moyamoya disease by improving cerebral hemodynamics in both the MCA and anterior cerebral artery territories.

Clinical outcome after 450 revascularization procedures for moyamoya disease

Object

Moyamoya disease (MMD) is a rare cerebrovascular disease mainly described in the Asian literature. To address a lack of data on clinical characteristics and long-term outcomes in the treatment of MMD in North America, the authors analyzed their experience at Stanford University Medical Center. They report on a consecutive series of patients treated for MMD and detail their demographics, clinical characteristics, and long-term surgical outcomes.

Methods

Data obtained in consecutive series of 329 patients with MMD treated microsurgically by the senior author (G.K.S.) between 1991 and 2008 were analyzed. Demographic, clinical, and surgical data were prospectively gathered and neurological outcomes assessed in postoperative follow-up using the modified Rankin Scale. Association of demographic, clinical, and surgical data with postoperative outcome was assessed by chi-square, uni- and multivariate logistic regression, and Kaplan-Meier survival analyses.

Results

The authors treated a total of 233 adult patients undergoing 389 procedures (mean age 39.5 years) and 96 pediatric patients undergoing 168 procedures (mean age 10.1 years). Direct revascularization technique was used in 95.1% of adults and 76.2% of pediatric patients. In 264 patients undergoing 450 procedures (mean follow-up 4.9 years), the surgical morbidity rate was 3.5% and the mortality rate was 0.7% per treated hemisphere. The cumulative 5-year risk of perioperative or subsequent stroke or death was 5.5%. Of the 171 patients presenting with a transient ischemic attack, 91.8% were free of transient ischemic attacks at 1 year or later. Overall, there was a significant improvement in quality of life in the cohort as measured using the modified Rankin Scale (p < 0.0001).

Conclusions

Revascularization surgery in patients with MMD carries a low risk, is effective at preventing future ischemic events, and improves quality of life. Patients in whom symptomatic MMD is diagnosed should be offered revascularization surgery.

Cerebral hemodynamics as a predictor of stroke in adult patients with moyamoya disease: a prospective observational study

Moyamoya disease is an obliterative vasculopathy of the large arteries at the base of the brain. In the US, it most commonly affects women in their 3rd and 4th decades of life, frequently causing ischemic stroke. The natural history of this disorder is not well described. It is very likely that hemodynamic factors play an important role in the risk of future stroke, as has been established in atherosclerotic carotid occlusive disease. The authors describe an ongoing, prospective observational study designed to test the hypothesis that increased oxygen extraction in the cerebral hemisphere beyond the occlusive lesion is a predictor of subsequent risk of ipsilateral stroke in medically treated patients with moyamoya phenomenon. On enrollment, all patients undergo regional measurements of cerebral oxygen extraction fraction (OEF) with PET. Information on baseline clinical, laboratory, epidemiological, and angiographic risk factors are obtained at the time of the PET study. Decisions regarding surgery are made by the treating physicians based on clinical information while being blinded to PET data. Patients undergo follow-up at 6-month intervals to determine the subsequent risk of ipsilateral stroke. All patients will return at 1 and 3 years for repeat PET studies. Secondary, exploratory, aims of this longitudinal and blinded study are to determine other predictive factors for stroke in this population; to determine preliminary estimates of the effects of different medical treatment regimens in this population; to determine the temporal changes in hemodynamic impairment in medically treated patients; to determine the effects of surgery on hemodynamic impairment in the subset of patients who undergo surgical revascularization; and to obtain estimates of surgical complication rates for patients with and without hemodynamic impairment.

De novo development of moyamoya disease in an adult female. Case report

The origin of moyamoya disease remains unknown. The onset of the angiographically apparent changes of typical moyamoya disease occurs in childhood, but de novo development of the disease has not been confirmed angiographically. The authors report on a case of de novo development of moyamoya disease in a middle-aged female whose cerebral angiography demonstrated no abnormal findings 5 years previously. To the best of the authors' knowledge, this case is the first reported instance of de novo development of definite moyamoya disease verified angiographically. This case demonstrates that the de novo development of moyamoya disease in a middle-aged adult did in fact occur, and angiographically visible features of the disease took < 5 years to complete.

The contribution of imaging in diagnosis, preoperative assessment, and follow-up of moyamoya disease

The aim of this review was to evaluate the imaging tools used in diagnosis and perioperative assessment of moyamoya disease, with particular attention to the last decade.

ADDITIONAL SURGERY FOR POSTOPERATIVE ISCHEMIC SYMPTOMS IN PATIENTS WITH MOYAMOYA DISEASE

OBJECTIVE

In patients with moyamoya disease, surgery to revascularize the ischemic brain is a recommended treatment. However, there are a few patients who require additional revascularization surgery because of progression of the disease. Even patients who show no postoperative ischemic symptoms at first may experience late deterioration. We performed additional surgery for such lesions using occipital artery (OA)–posterior cerebral artery (PCA) bypass with indirect revascularization. The efficacy of the procedure is reported.

METHODS

We treated 3 patients with moyamoya disease who showed a transient ischemic attack after revascularization surgery. Three female patients, ranging in age from 6.0 to 35.2 years (mean age, 23.8 years) at the time of surgery, with ischemic symptoms (leg monoparesis in 2, visual impairment in 1) underwent the additional revascularization procedure. Preoperatively, all patients underwent indirect and/or direct revascularization surgery for initial treatment. All patients showed progression of the disease, especially in the PCA. OA–PCA bypass with encephalogaleodurosynangiosis and burr hole surgery were performed for postoperative ischemic symptoms.

RESULTS

All patients showed clinical and radiological improvement. The transient ischemic attack was improved in all 3 patients. They did not complain of transient ischemic attack in the recent follow-up period. Follow-up magnetic resonance imaging showed no additional cerebral infarction. Magnetic resonance angiography showed widening of the OA and development of peripheral collateral vessels. Postoperative single-photon emission computed tomographic studies showed marked increase of uptake in both anterior cerebral artery and PCA territories. Cerebral vasodilatory capacity evaluated by an acetazolamide test also showed marked improvement. One patient showed postoperative cerebral edema as a result of focal cerebral hyperperfusion.

CONCLUSION

OA–PCA anastomosis with indirect revascularization was effective for postoperative ischemia that showed symptoms in the anterior cerebral artery and PCA territories as a result of progression of a PCA lesion.

Moyamoya disease: current concepts and future perspectives

Moyamoya disease is an uncommon cerebrovascular disease that is characterised by progressive stenosis of the terminal portion of the internal carotid artery and its main branches. The disease is associated with the development of dilated, fragile collateral vessels at the base of the brain, which are termed moyamoya vessels. The incidence of moyamoya disease is high in east Asia, and familial forms account for about 15% of patients with this disease. Moyamoya disease has several unique clinical features, which include two peaks of age distribution at 5 years and at about 40 years. Most paediatric patients have ischaemic attacks, whereas adult patients can have ischaemic attacks, intracranial bleeding, or both. Extracranial-intracranial arterial bypass, including anastomosis of the superficial temporal artery to the middle cerebral artery and indirect bypass, can help prevent further ischaemic attacks, although the beneficial effect on haemorrhagic stroke is still not clear. In this Review, we summarise the epidemiology, aetiology, clinical features, diagnosis, surgical treatment, and outcomes of moyamoya disease. Recent updates and future perspectives for moyamoya disease will also be discussed.

Circulating endothelial progenitor cells as a pathogenetic marker of moyamoya disease

Moyamoya disease (MMD) is an unusual form of chronic cerebrovascular occlusive disease that involves the formation of characteristically abnormal vessels. Recent studies have reported that colony-forming unit (CFU) and outgrowth cells represent a subpopulation of endothelial progenitor cells (EPCs). Here, we attempted to determine the significance of CFU number and outgrowth cell yield in MMD. Endothelial progenitor cells were isolated from the blood of 24 adult MMD patients and from 48 age- and risk factor-matched control subjects. After 7 days of culture, CFUs were determined, and yields of outgrowth cells were measured during 2 months of culture. The EPC function was also evaluated using matrigel plate assays. It was found that CFU numbers were significantly lower in MMD patients than in controls. Moreover, during long-term culture, outgrowth cells were isolated from only 10% of control subjects but from 33% of MMD patients, and CFU numbers and tube formation were found to be lower in advanced MMD cases than in those with early stage disease, whereas outgrowth cells were more frequently detected in those with early MMD and moyamoya vessels than in those with advanced disease. These characteristics of circulating EPCs reflect mixed conditions of vascular occlusion and abnormal vasculogenesis during the pathogenesis of MMD.

Intracranial hemodynamic changes during adult moyamoya disease progression

Background and purpose

This study evaluated the changes in blood flow velocity in the anterior and posterior intracranial circulations according to the progression of moyamoya disease in adult patients.

Methods

We evaluated Suzuki's angiographic stage and mean blood flow velocity (MBFV) changes in intracranial vessels from both sides in 19 adult moyamoya patients. We then analyzed the linearity of MBFV changes from early to late moyamoya stages in each intracranial vessel using piecewise linear regression models.

Results

The MBFV in the middle cerebral artery, terminal internal carotid artery, and anterior cerebral artery increased non linearly until stage III, and then decreased progressively up to stage VI. The ophthalmic artery also showed nonlinear velocity changes, with an increase in MBFV up to stage IV, followed by a decrease in MBFV up to stage VI. The MBFV of the basilar artery increased linearly from a normal velocity at an early moyamoya stage to a stenotic velocity at a late stage. There was no statistically significant regression model for the relationship between the MBFV in the posterior cerebral artery and moyamoya stage.

Conclusions

The nonlinear and/or linear MBFV changes associated with variable intracranial vessels might be useful in initial and follow-up evaluations of different stages of moyamoya disease.

Progressive moyamoya syndrome associated with de novo formation of the ipsilateral venous and contralateral cavernous malformations: case report

BACKGROUND

Association of moyamoya disease with multiple vascular malformations is extremely rare.

CASE PRESENTATION

A 33-year-old man, who had been affected with moyamoya syndrome with TIA during the past 3 years, was admitted to our hospital because of crescendo TIAs with numbness in his right hand and dysarthria. Magnetic resonance angiography showed apparent progression of the steno-occlusive changes bilaterally. We then planned surgical revascularization on the symptomatic side. At the time of readmission for surgery, an asymptomatic small intracerebral hemorrhage in the right frontal cortex was found, which presented on MRI as a CCM. Cerebral angiogram showed avascular lesion corresponding to the location of CCM as well as a newly formed venous malformation on the left side. One month later, STA-MCA anastomosis with pial synangiosis was performed without complications. Significant improvement in CBF on the left hemisphere was confirmed by postoperative single-photon emission CT. There were no ischemic changes on a postoperative MRI, and STA-MCA bypass was apparently patent by MRA. The TIA completely disappeared after surgery, and the patient was discharged without neurologic deficit. Persistence of the CCM and venous malformation were confirmed by T2*-weighted image and 3-dimensional contrast-enhanced gradient echo/SWI 4 months after surgery, respectively.

CONCLUSION

The association of moyamoya syndrome with CCM and venous malformation is extremely rare. The coincidence of the progressive moyamoya syndrome with these newly formed vascular malformations may give a clue to the underlying mechanism of the progression of this rare entity.

Prevalence and clinicoepidemiological features of moyamoya disease in Japan: findings from a nationwide epidemiological survey

BACKGROUND AND PURPOSE

The objectives of the present study were to estimate an annual number of patients with moyamoya disease in Japan and to describe the clinicoepidemiological features of the disease.

METHODS

The study consisted of 2 questionnaire surveys, which were distributed to randomly selected departments of neurosurgery, internal medicine, neurology, cerebrovascular medicine, and pediatrics in hospitals throughout Japan. The first survey inquired about the number of the patients treated in 2003, and the second requested additional detailed clinicoepidemiological information about each patient identified in the first survey.

RESULTS

In 2003, the total number of patients treated in Japan was estimated at 7700 (95% confidence interval, 6300 to 9300). Sex ratio (women to men) of the patients was 1.8. For men, the peak of moyamoya disease was observed in patients aged 10 to 14 years and for women aged 20 to 24 years. Annual rate of newly diagnosed cases in 2003 was 0.54 per 100,000 population. Family history of moyamoya disease was found in 12.1% of the patients. The majority (77.9%) were treated as outpatients.

CONCLUSIONS

Although the clinicoepidemiological features of the patients in the present study were almost similar to those obtained in previous ones, the estimated prevalence of moyamoya disease in Japan has almost doubled during the recent decade (3900 in 1994 and 7700 in 2003). The increase could partly be explained by the increase in newly diagnosed cases (0.35 in 1994 and 0.54 in 2003 per 100,000 population).

Microembolic signals are associated with progression of arterial lesion in Moyamoya disease: A case report

Transcranial Doppler ultrasonography (TCD) and magnetic resonance angiography (MRA) confirmed a rapid progression of arterial lesion in Moyamoya disease after the patient gave birth. TCD could initially detect a large number of microembolic signals (MES) at the distal portion of stenotic lesions. After MRA showed the development of stenotic lesions 10 days after first TCD monitoring, MES were absent. MES may be related to the clinical activity of Moyamoya disease.

Radiological Findings, Clinical Course, and Outcome in Asymptomatic Moyamoya Disease

BACKGROUND AND PURPOSE

Although the development of a noninvasive MR examination has increased the opportunity to identify asymptomatic patients with moyamoya disease who have experienced no stroke episodes, their clinical features are still unclear. This was the first multicenter, nation-wide survey focused on asymptomatic moyamoya disease in Japan and was designed to clarify their clinical features.

METHODS

A clinical database of asymptomatic patients with moyamoya disease was collected from 12 participating hospitals in Japan between 2003 and 2006. In total, 40 patients were enrolled in this historical prospective cohort study. Of these, 6 underwent surgical revascularization, including superficial temporal artery to middle cerebral artery anastomosis and/or pial synangiosis. Their demographic and radiological findings as well as outcome were evaluated.

RESULTS

On initial evaluation, cerebral infarction and disturbed cerebral hemodynamics were detected in approximately 20% and 40% of the involved hemispheres, respectively. Angiographical stage was more advanced in more elderly patients. Of 34 nonsurgically treated patients, 7 experienced transient ischemic attack (n=3), ischemic stroke (n=1), or intracranial bleeding (n=3) during follow-up periods (mean, 43.7 months). The annual risk for any stroke was 3.2%. Disease progression was associated with ischemic events or silent infarction in 4 of 5 patients. No cerebrovascular event occurred in the 6 patients who underwent surgical revascularization.

CONCLUSIONS

The findings revealed that asymptomatic moyamoya disease is not a silent disorder and may potentially cause ischemic or hemorrhagic stroke. Asymptomatic patients with moyamoya disease should be carefully followed-up to further clarify their outcome and to establish the management guideline for them.

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.

Unilaterally Symptomatic Moyamoya Disease in Children: Long-term Follow-up of 20 Patients

OBJECTIVE:

In unilaterally symptomatic moyamoya disease in children, it remains controversial whether bypass surgery should be performed on the asymptomatic side along with on the symptomatic side. We aimed to verify the validity of our strategy of only performing bypass surgery on the symptomatic side.

METHODS:

Among 91 pediatric patients with moyamoya disease who underwent bypass surgery in our department between 1980 and 2004, 20 with unilateral ischemic symptoms who were followed for more than 60 months were analyzed in the present study. Initially, we only performed bypass surgery on the symptomatic side for all 20 patients. Among these 20 patients, five developed frequent transient ischemic attacks in the initially asymptomatic side and underwent a second bypass surgery on that side (Group A), eight developed sporadic transient ischemic attacks and were followed up without surgery (Group B), and seven did not experience any ischemic symptoms on the asymptomatic side (Group C).

RESULTS:

In total, 18 patients progressed well without cerebral infarctions after their last surgery, although some showed deterioration of angiographic stenosis and a transient decrease in the regional cerebral blood flow or cerebral perfusion reserve. One patient in Group A had an intraventricular hemorrhage 5 years after the second operation, and one in Group B had a minor stroke on the initially asymptomatic side.

CONCLUSION:

In unilaterally symptomatic moyamoya disease, bypass surgery for the asymptomatic side can be delayed until the development of ischemic symptoms, such as frequent transient ischemic attacks.

Clinical Features and Outcome in North American Adults With Moyamoya Phenomenon

Background and Purpose— To describe baseline clinical features and outcomes of adults with moyamoya phenomenon treated at a single North American institution.

Methods— We identified 34 adults with moyamoya phenomenon by review of angiographic records. Clinical presentation and baseline stroke risk factors were obtained by chart review. Follow-up was obtained prospectively. A 5-year Kaplan-Meier stroke risk was calculated.

Results— The median age was 42 (range 20 to 79) years. Twenty-five were women. The initial symptom was ischemia, hemorrhage, or asymptomatic in 24, 7, and 3 patients, respectively. Twenty-two had bilateral involvement and 12 had unilateral moyamoya vessels. Baseline stroke risk factors were similar between groups. The median follow-up in 31 living patients was 5.1 (range 0.2 to 19.6) years. Fourteen patients were treated with surgical revascularization (20 total hemispheres). In medically treated symptomatic hemispheres, the 5-year risk of recurrent ipsilateral stroke was 65% after the initial symptom and 27% after angiographic diagnosis. Patients with bilateral involvement presenting with ischemic symptoms were at the highest risk of subsequent stroke (n=17, 5-year risk of stroke with medical treatment after first symptom of 82%). In surgically treated hemispheres, the 5-year risk of perioperative or subsequent ipsilateral stroke or death was 17%. This was significantly different compared with medical treatment after first symptom ( P =0.02) but not after angiographic diagnosis.

Conclusion— Moyamoya phenomenon in North American adults is associated with a high risk of recurrent stroke, particularly those with bilateral involvement and ischemic symptoms. These data suggest a potential benefit with surgery if diagnosis could be made earlier.

Progression of unilateral moyamoya disease: A clinical series

BACKGROUND

The natural history of unilateral moyamoya disease (MMD) in adult patients is not clearly described in the literature. We present a series of 18 patients with unilateral MMD and analyze the risk factors for progression to bilateral disease.

METHODS

A retrospective review of 157 MMD patients treated at Stanford University Medical Center from 1991 to 2005 identified 28 patients with unilateral MMD (defined as none, equivocal or mild involvement on the contralateral side).

RESULTS

Eighteen patients (5 males and 13 females) were identified with unilateral MMD and angiographic follow-up of > or =5 months. Mean radiologic follow-up (+/- standard error of the mean) was 19.3 +/- 3.4 months and mean clinical follow-up was 24.5 +/- 3.7 months. Five patients had childhood onset MMD and 13 patients had adult onset disease. Angiographic progression from unilateral to bilateral disease was seen in 7 patients (38.9%) at a mean follow-up of 12.7 +/- 2.4 months. Four of the 7 patients had significant clinical and radiologic progression requiring surgical intervention. Five of 7 patients that progressed had adult onset MMD. The presence of equivocal or mild stenotic changes of the contralateral anterior cerebral artery (ACA), middle cerebral artery (MCA) or internal carotid artery (ICA) was an important predictor of progression (p < 0.01); 6 of 8 patients (75%) with equivocal or mild contralateral disease progressed, whereas only 1 of 10 patients (10.0%) with no initial contralateral disease progressed to bilateral MMD. One patient had mild or equivocal MCA, ICA and ACA stenosis at the time of initial diagnosis and this patient progressed.

CONCLUSIONS

Contralateral progression in the adult form occurs more commonly than previously reported. The presence of minor changes in the contralateral ACA, intracranial ICA and MCA is an important predictor of increased risk of progression. Patients with a completely normal angiogram on the contralateral side have a very low risk of progression.