Moyamoya disease is the narrowing and ultimately closure of the internal carotid arteries,
the two largest arteries feeding the brain. Moyamoya disease is progressive, meaning the
vessel walls will continue to narrow over time. The cause of moyamoya disease is unknown,
although genetics are a likely factor and it affects mostly children and adolescents.
In response to the narrowing of the blood vessels, the body will begin to grow many small
blood vessels to bypass the blockage. The word Moyamoya means “puff of smoke” in Japanese,
and refers to the appearance of these networks of new blood vessels. The condition first
was identified in Japan, where its incidence is higher than elsewhere.
The findings of narrow blood vessels at the base of the brain can also be associated with
other diseases, and is referred to as Moyamoya syndrome. This syndrome can be found in
patients with atherosclerotic disease or hardening of the arteries, Down syndrome,
neurofibromatosis, or sickle cell anemia.
UPMC offers a variety of surgical techniques to treat Moyamoya disease, depending upon the
exact location of the disease.
CT and MRI scans may provide initial indications of the disease. If the disease is suspected,
cerebral angiography, a test that creates images of the blood flow through the brain, is
conducted to establish the diagnosis. UPMC is one of the few centers in the nation to have
all major methods of measuring brain blood flow.
Because Moyamoya disease may be an inherited genetic abnormality, a physician will also
review the patient’s family history.
Signs and symptoms of Moyamoya disease may include:
- Aphasia (loss of ability to use or comprehend words)
- Blurred vision
- Cognitive (reasoning or remembering) impairment
- Involuntary movements
- Numbness in arms and legs
- Severe headaches
Adults with Moyamoya disease also often experience hemorrhagic stroke (a burst blood vessel inside the brain).
There is no evidence that medications slow the progression of Moyamoya disease. At UPMC,
highly trained and experienced neurosurgeons use revascularization procedures to bypass
narrowed or blocked arteries and restore blood supply to the brain.
Revascularization procedures performed at UPMC include:
- External carotid to internal carotid (EC-IC) bypass: During this procedure, the
surgeon attaches one of the arteries in the scalp (superficial temporal artery)
to one of the major arteries in the brain (middle cerebral artery).
- EDAS (encephaloduroarteriosynangiosis): During this procedure, the surgeon frees up,
without severing, a scalp artery over a course of several inches and then makes a
small temporary opening in the skull directly beneath the artery. The artery is then
sutured to the surface of the brain and the bone replaced.
- EMS (encephalomyosynangiosis): During this procedure, a muscle in the temple region
of the forehead is dissected and placed onto the surface of the brain through an
opening in the skull. Multiple burr holes are drilled into the skull to allow new
blood vessels to grow.
- STA-MCA (superficial temporal artery-middle cerebral artery) bypass: During this
procedure, a scalp artery is directly sutured to a brain surface artery to bring
blood directly to where the brain needs it most.
In rare circumstances, our endovascular team will evaluate the patient for minimally invasive
alternatives such as angioplasty and/or stenting to widen the narrowed artery.
Without surgery, the majority of patients with Moyamoya disease will experience mental decline
and multiple strokes because of the progressive narrowing of the arteries. If untreated,
Moyamoya disease can be fatal.