Usefulness of Direct Bypass to Prevent Future Stroke in the Hemorrhagic Type Moyamoya Disease

Abstract

We evaluated the usefullness of superficial temporal to middle cerebral artery (STA-MCA) bypass to prevent of future stroke, including rebleeding or an ischemic event, in hemorrhagic-type moyamoya disease compared with the effects of indirect bypass or conservative management.
We examined 23 patients with hemorrhagic-type moyamoya disease concerning their treatment and clinical course after an initial hemorrhagic episode. The mean age of the patients was 43 years, and the follow-up period was from 0.8 to 15.1 years, with a mean of 9.3 years. Twelve patients were conservatively managed. Among the 11 surgically treated patients, STA-MCA bypass was performed on 6 and encephaloduroarteriosynangiosis (EDAS) on the other 5. Ten patients (43%) presented with an ischemia or rebleeding during the follow-up period. The incidence of future strokes in the patients undergoing an STA-MCA bypass was significantly lower (p<0.05) than that in the patients treated conservatively or with EDAS. A comparison of Kaplan-Meier plots of stroke-free time in the patients treated with direct bypass and those treated conservatively or with indirect bypass showed a significant difference (p<0.05) in favor of direct bypass.
The usefulness of the STA-MCA bypass in patients with hemorrhagic-type moyamoya disease to prevent recurrent hemorrhage or an ischemic event was statistically confirmed.