Hemorrhagic Moyamoya Disease : A Recent Update

Area of Science:

• Neurology
• Neurosurgery
• Vascular Neurology

Background:

• Moyamoya disease (MMD) is a progressive cerebrovascular disorder characterized by internal carotid artery stenosis and abnormal basal brain vasculature.
• MMD involves a shift in cerebral blood supply from the internal carotid (IC) to the external carotid (EC) system, which can lead to ischemic or hemorrhagic events.
• Hemorrhagic MMD presents a high risk of re-bleeding, often associated with specific angiographic features like dilated choroidal collaterals and posterior cerebral artery involvement.

Purpose of the Study:

• To update the current management strategies for hemorrhagic Moyamoya disease.
• To evaluate the outcomes of surgical revascularization in patients with hemorrhagic MMD.
• To identify optimal surgical approaches for preventing hemorrhagic manifestations in MMD.

Main Methods:

• Review of current literature and clinical data on Moyamoya disease management.
• Analysis of angiographic findings associated with hemorrhagic MMD and re-bleeding risk.
• Assessment of surgical revascularization outcomes, specifically extracranial-intracranial bypass, in hemorrhagic MMD patients.

Main Results:

• Surgical revascularization, particularly EC-IC bypass, is effective in improving cerebral blood flow and reducing ischemic events in MMD.
• Evidence suggests extracranial-intracranial bypass significantly lowers the re-bleeding risk in MMD patients with posterior hemorrhage.
• Specific angio-architectures, including extensive choroidal collaterals and posterior cerebral artery involvement, are linked to increased re-bleeding risk in hemorrhagic MMD.

Conclusions:

• Surgical revascularization is a crucial component in managing both ischemic and hemorrhagic Moyamoya disease.
• Extracranial-intracranial bypass shows promise in mitigating the high re-bleeding risk associated with hemorrhagic MMD.
• Further investigation is needed to refine surgical strategies for optimal prevention of hemorrhagic events in MMD patients.