A nationwide survey on unilateral moyamoya disease in Japan

Moyamoya disease (MMD) is a unique occlusive disease of the bilateral internal carotid arteries; compensation for occlusion results in rich arterial collaterals at the base of the brain. The clinical features of unilateral MMD, confirmed by typical angiographic evidence of MMD unilaterally and normal or equivocal contralateral findings, are not well known. To identify the clinical features of unilateral MMD in Japan, a nationwide survey was conducted.

The questionnaire was directly mailed to 241 departments that reported treating unilateral MMD patients in a primary survey. We ascertained the sex, age, family history, clinical manifestation, radiological findings, treatments, course of the disease, and daily activity of unilateral MMD patients.

A total of 114 departments replied to the questionnaire. The data of 203 patients (118 female and 85 male; female to male ratio 1.4:1) were registered and analyzed. The mean age was 40.2 years old with a peak occurring in the fifties. Twenty-one patients (10.7%) exhibited familial MMD. The clinical symptoms are motor weakness 57 (26.8%), headache 37 (17.4%), transient ischemic attack 35 (16.4%), and no symptom 30 (14.1%). The MMD types determined by imaging included ischemic type in 64 patients (32.5%), bleeding type in 51 (25.9%), and normal in 82 (41.6%). The development of moyamoya vessels was mild in 78 patients (43.9%) and most patients (81.1%) were accompanied with cerebral hypoperfusion. Medical treatment or vascular reconstruction was employed for more than half of the patients.

The clinical feature of unilateral MMD was revealed in this nationwide study. Unilateral MMD was predominant in adults and the development of moyamoya vessel was relatively less prevalent.