Stenotic changes of the posterior cerebral artery are a major contributing factor for cerebral infarction in moyamoya disease

Background: Some patients with moyamoya disease (MMD) show broad infarction with moderate internal carotid artery (ICA) stenosis, whereas others with complete ICA occlusion show no infarction. This suggests that other factors contribute to the occurrence of infarction. Contributing factors predictive of cerebral infarcts must be identified for the prevention of infarction and the consequent neurological deficits. Methods: We examined data from 93 patients with confirmed MMD for the presence of infarction (n = 72), transient ischemic attack (TIA, n = 41), asymptomatic presentation (n = 51), or hemorrhage (n = 22) in 186 bilateral cerebral hemispheres. We analyzed the relationship between the occurrence of infarction and several clinical factors, such as steno-occlusive status or the site of the ICA and posterior cerebral artery (PCA). Results: The incidence of PCA steno-occlusive lesions was significantly higher in infarcted (77.8%) than in non-infarcted hemispheres (TIA, 14.6%; asymptomatic, 9.8%; hemorrhagic 9.1%; P < 0.01). The steno-occlusive site of ICA was also a significant factor (P < 0.05). There was no significant correlation between the occurrence of infarction and the steno-occlusive status of the ICA or grade of the moyamoya vessels. Multivariate statistical analysis demonstrated that the PCA steno-occlusive changes were an important contributing factor for infarction (P < 0.0001). Conclusions: This is the multivariate statistical analysis study identifying PCA steno-occlusive lesions as the most important independent factor that is predictive to cerebral infarction in moyamoya patients. The prediction and inhibition of PCA steno-occlusive changes may help to prevent cerebral infarction.