Moyomoya: The ‘puff of smoke’ disease and its treatment strategies

By Naveed Saleh, MD, MS | Medically reviewed by James Beckerman, MD, FACC
Published September 30, 2022

Key Takeaways

  • Moyamoya is a rare cerebrovascular disease that affects mostly children, although it can occur in adults.

  • With moyamoya, early surgical intervention is integral to reduce the risk of permanent disability. Treatment consists of direct bypass, indirect bypass, or some combination.

  • Intriguing research involves the use of autologous bone marrow stem cells to treat this disease.

Moyamoya is a rare cerebrovascular disease that involves the enlargement of lenticulostriate and thalamoperforating arteries. Its name is derived from a Japanese term meaning “puff of smoke” due to how it appears on imaging.

Early surgical intervention is a common strategy in treating moyamoya, but research involving bone marrow stem cells has shown promise in reducing the risk factors of this disease.

Moyamoya origins

Like takotsubo cardiomyopathy (ie, broken-heart syndrome), which means “octopus pot” in Japanese and refers to the shape of the left ventricle on imaging, moyamoya disease is also named for its appearance on imaging.

Moyamoya refers to the compensatory enlargement of lenticulostriate and thalamoperforating arteries seen near the top of the internal carotid on angiography.

First described by Japanese investigators in 1957, moyamoya is a chronic, progressive cerebrovascular disease. Adults with this condition continue to manifest additional cognitive and neurological deficits over time. The death rate in adults is nearly double that of children (10% vs 4.3%, respectively).

Incidence of moyamoya

Moyamoya is a rare disease that most commonly affects children.

Publishing in Computational Intelligence and Neuroscience, Chinese researchers estimated that the incidence of moyamoya disease is 4%, with 1.5% exhibiting family history.[] Its etiology is unknown.

In children, the first symptom is usually stroke or transient ischemic attacks, along with muscle weakness and hemiparesis. Other symptoms resulting from artery blockage include seizures, headaches, alterations in consciousness, visual problems, and involuntary movements. Although adults may experience similar symptoms, they often initially present with a hemorrhagic stroke.[]

The continuous thickening of the walls of the internal carotid occurs progressively throughout the disease’s six stages (I to VI), which reflect progressive stenosis. In stage VI, the moyamoya vessels disappear and there is total arterial blockage.

Diagnosis of moyamoya is supported by computed tomography angiography, brain MRI, and catheter angiography to determine the stage of the disease, collateralization, and the dimensions of potential donor vessels.

Treatment strategies

Thanks to medical advances, moyamoya can be diagnosed early and treated over time.

Early treatment is imperative because the damage caused by moyamoya can be irreversible.

Treatment consists of anticoagulants to decrease stroke risk and various types of surgery to revascularize the brain by unblocking narrowed arteries. Bypass is another option. Revascularization is often more successful in children than adults. Some patients experience no recurrence of the disease or associated symptoms following surgery.

Bypasses include direct or indirect, as well as combined extracranial-to-intracranial (EC-IC). Indirect bypass is performed without direct anastomosis; this type of bypass moves vascularized tissue to the brain’s surface to facilitate angiogenesis via burr holes or dural inversion. Although indirect bypass obviates proposed damage from hyperperfusion, it takes several months to a year for new blood vessels to grow and blood flow to be re-established.

Because neo-angiogenesis is more successful in children than adults, adults usually receive direct bypasses.

“Controversy remains as to which surgical procedure is superior due to heterogeneous techniques and outcome measures used,” wrote the authors of a review published in Frontiers in Surgery.[]

“Prior studies have shown improved functional and symptomatic outcomes, angiographic revascularization, recurrent stroke, and decreased hemorrhage rates when utilizing direct bypass compared to indirect bypass for revascularization in the setting of moyamoya disease,” the authors added.

Pioneered in 1969, EC-IC is a common intervention in adult patients with moyamoya disease. It involves a direct anastomosis between a donor and recipient artery (eg, superficial temporal and middle cerebral arteries). Combined bypass strategies allow for immediate improvements in cerebral bypass and later collateralization stemming from an indirect bypass.

Stem cell approach studied

An intriguing potential treatment for moyamoya disease involves the use of autologous bone marrow stem cells (ABMSC). In the study published in Computational Intelligence and Neuroscience, Chinese researchers compared the outcomes of ABMSC with bypass in 52 moyamoya patients.

“Our study suggests that the treatment of [ABMSC] was beneficial to balance the inflammatory response of disorders, reduce the damage of vascular tissue in the brain, and regulate tissue repair by co-acting with various inflammatory factors as compared to traditional surgery,” the authors wrote.

"We also have found that the risk factors of intracranial infection after [ABMSC transplantation] were less as compared to those after conventional surgery."

Zhao, et al.

What this means for you

Although a diagnosis of moyamoya disease is rare in Western populations, it can be considered as a differential diagnosis in individuals with chronic, progressive cerebrovascular disease. Family history is an important red flag. Early surgical treatment is imperative. A stem cell-based approach may show promise as a future treatment.

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