Approach Considerations
Pharmacologic therapy for moyamoya disease is disappointing. Therapy is primarily directed at complications of the disease. If intracerebral hemorrhage has occurred, then management of hypertension (if present) is imperative. In cases of severe stroke, intensive care unit (ICU) monitoring is indicated until the patient's condition stabilizes. If the patient has had an ischemic stroke, consider anticoagulation or antiplatelet agents.
Activity
Rehabilitation with physical therapy, occupational therapy, and speech therapy should be considered, depending on the neurologic impairment. The extent of therapy can range from bedside treatment to full, comprehensive inpatient rehabilitation. The latter would include physical, occupational, speech, and cognitive therapy. The condition of the patient, including active comorbidities, dictates his or her involvement in rehabilitation therapy.
Anticoagulation and Antiplatelet Therapy
The rationale behind the administration of anticoagulation and antiplatelet agents is the prevention of further strokes, especially in stenotic vessels (where further infarction can occur if occlusion progresses).
These medications are not approved by the US Food and Drug Administration (FDA) specifically for use in moyamoya disease. Therefore, the decision to treat patients with anticoagulants such as heparin (and, in some cases, warfarin, for long-term anticoagulation) or antiplatelet agents such as aspirin rests on the following: angiogram findings, severity of stroke, and risk/benefit analysis by physicians who are experienced in stroke treatment.
Direct and Indirect Anastomosis
As previously stated, patients with moyamoya disease who present for treatment while symptoms are evolving have a better prognosis than do those who present with static symptoms (which probably indicate a completed stroke).
Various surgical procedures have been used in the treatment of moyamoya disease, with the goal of revascularizing the ischemic hemisphere, including the following [12] :
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Superficial temporal artery–middle cerebral artery (STA-MCA) anastomosis
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Encephaloduroarteriosynangiosis (EDAS) [13]
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Encephaloduroarteriomyosynangiosis (EDAMS)
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Pial synangiosis
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Omental transplantation
These procedures can be divided into 2 groups depending on whether they involve direct or indirect anastomosis. The STA-MCA anastomosis is a direct revascularization procedure, whereas indirect procedures depend on the subsequent formation of collateral vessels to increase blood delivery. Which of these procedures is most effective remains controversial. Sufficient evidence suggests that surgical revascularization procedures result in some symptomatic benefits along with demonstration of improved blood flow. Direct and/or combined procedures provide improved vascularization. However, data proving sustained or improved long-term outcomes are insufficient. [14, 15]
STA-MCA anastomosis is very difficult in children younger than 2 years because of the small diameter of the STA. In these cases, EDAS may be more suitable. This procedure sometimes has failed because of poor revascularization. Hoffman suggested that this is due to the presence of atrophy and a layer of spinal fluid between the pia and the arachnoid tissue. [16] Division of the arachnoid membrane and placement of the STA directly on the pial membrane help to avoid the problem. In cases of EDAS failure, EDAMS can be considered.
Consultations
Initial neurologic consultation is imperative. A neurologist can document neurologic deficits, consider the differential diagnosis, conduct testing to validate suspected etiologies, and commence medical management as indicated.
Neuroradiology consultation is needed to help determine the extent of radiologic testing needed (ie, MRA vs conventional angiography). Based on the results of these tests, a neurosurgeon can decide if surgical intervention will be helpful.
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Schematic representation of the circle of Willis, arteries of the brain, and brain stem.
