Comparison between moyamoya disease and moyamoya syndrome in Israel

Background and aims: Moyamoya is a chronic brain vasculopathy involving the distal intracranial internal carotid artery (ICA) or proximal middle cerebral artery (MCA). Moyamoya patients can be divided into those with primary moyamoya disease (MMD) and those with moyamoya secondary to other known causes such as intracranial atherosclerosis (moymoya syndrome [MMS]). Our aim was to compare the characteristics of MMD patients to those of MMS patients in a sample of Israeli patients seen over the course of 20 years at a tertiary referral center. Methods: Included patients were diagnosed with either MMD or MMS based on typical imaging findings and the presence or absence of known concomitant vascular risk factors or associated disorders and vascular disease. Patients with MMS were compared to those with MMD. Demographics, symptoms, signs, and radiological data were compared between the groups. Treatment options and long-term rates of recurrent stroke and functional outcome were also studied. Results: Overall, 64 patients were included (25 MMD, 39 MMS). Patients with MMD were significantly younger (median IQR 20 (7-32) vs. 40 (19-52); p=0.035). Patients with MMS more often had vascular risk factors but there were no significant differences in clinical presentations or long-term disability rates between the groups and a similar proportion of patients underwent surgical interventions to restore hemispheric perfusion in both groups (48% vs. 44% MMS vs. MMD; p=0.7). Almost one in four patient had a recurrent stroke after the initial diagnosis in both groups. Most recurrences occurred in the pre-surgery period in the MMS group and in the postsurgery period in the MMD group. Conclusions: There were no statistically significant differences in clinical or radiological presentations between the MMS and MMD patients. The course is not benign with recurrent stroke occurring in as many as 25%. More data is needed in order to identify those at high risk for stroke occurrence and recurrence.