The clinical features of adult unilateral moyamoya disease: does it have the same clinical characteristics as typical moyamoya disease?

BACKGROUND: The cerebral hemodynamics in unilateral moyamoya disease have not been clarified. The present study was done to clarify the clinical characteristics of patients with unilateral moyamoya disease compared to those with typical moyamoya disease or occlusive lesions of the internal carotid artery, terminal portion or middle cerebral artery.

METHODS: We retrospectively analyzed patients who had unilateral or bilateral steno-occlusive lesions at the internal carotid artery terminal portion or proximal middle cerebral artery. We divided the patients into 3 groups: typical moyamoya (n = 25), unilateral moyamoya (n = 12) and nonmoyamoya (n = 44). Atherosclerotic risk factors and frequency of ischemic and hemorrhagic stroke were compared among the 3 groups. We also examined the extent of cerebral collateral vessels by angiography and used single-photon emission computed tomography to measure the regional cerebral blood flow (rCBF) at rest and after acetazolamide injection.

RESULTS: The data on age, sex, hyperlipidemia and smoking habits in the unilateral moyamoya group fell in between those of the typical moyamoya and nonmoyamoya groups. Stroke was less frequent in the unilateral moyamoya group compared to the typical moyamoya or nonmoyamoya groups (p < 0.05). The rCBF at rest and after acetazolamide injection were significantly higher in the unilateral moyamoya group than in the typical moyamoya and nonmoyamoya groups (p < 0.05).

CONCLUSIONS: Patients with unilateral moyamoya disease appear to have the lowest frequency of stroke and a reduced rCBF, despite the fact that they have more atherosclerotic risk factors than patients with bilateral lesions.