Correspondence
Moyamoya Disease and Moyamoya Syndrome
N Engl J Med 2009; 361:97-98July 2, 2009
- Article
To the Editor:
As the principal investigator of a National Institutes of Health (NIH)–funded natural-history study involving North American adults with moyamoya disease,1 I read with interest the review article on this disease and moyamoya syndrome by Scott and Smith (March 19 issue).2 There is one implicit, and, I believe, invalid, assumption in this otherwise thoughtful review: that the findings of the natural-history studies involving pediatric Asian populations are applicable to North American adults. I am writing to emphasize that the natural history of North American adults with this angiographic disorder is unknown. In addition, many adult patients in North America have a benign clinical course that is probably related to the development of sufficient collateral sources of blood flow in them. The phenotype of North American adult moyamoya disease is a woman in her fourth or fifth decade of life who presents with ischemic symptoms.3 This presentation differs from that reported in Asian studies.4 Finally, as noted by the authors, the moyamoya vessels that are the hallmark of the disorder are simply a distinctive form of collateralization that develops in response to an underlying vasculopathy. The nature of the occlusive vasculopathy is unknown and probably multifactorial, particularly in North American adults.5
5 ReferencesColin P. Derdeyn, M.D.
Washington University School of Medicine, St. Louis, MO 63110
derdeync@wustl.edu 1
Zipfel GJ ,Sagar J ,Miller JP , et al. Cerebral hemodynamics as a predictor of stroke in adult patients with moyamoya disease: a prospective observational study. Neurosurg Focus 2009;26:E6-E6
CrossRef | Medline2
Scott RM ,Smith ER . Moyamoya disease and moyamoya syndrome. N Engl J Med 2009;360:1226-1237
Full Text | Web of Science | Medline3
Hallemeier CL ,Rich KM ,Grubb RL Jr , et al. Clinical features and outcome in North American adults with moyamoya phenomenon. Stroke 2006;37:1490-1496
CrossRef | Web of Science | Medline4
Ikezaki K ,Inamura T ,Kawano T ,Fukui M . Clinical features of probable moyamoya disease in Japan. Clin Neurol Neurosurg 1997;99:Suppl 2:S173-S177
Web of Science | Medline5
Peerless SJ . Risk factors of moyamoya disease in Canada and the USA. Clin Neurol Neurosurg 1997;99:Suppl 2:S45-S48
CrossRef | Web of Science | Medline
To the Editor:
Moyamoya disease presents most often as a transient ischemic attack or stroke. Apart from surgical revascularization procedures, medical therapeutic measures such as antiplatelet agents and even anticoagulation have been used for stroke prevention. In completed stroke, as confirmed by means of diffusion-weighted magnetic resonance imaging, antiplatelet agents should be administered to reduce the formation of microthrombi at the site of the stenosis.
We would like to raise a question about thrombolytic therapy with the use of tissue plasminogen activator (t-PA), which is today an accepted treatment for ischemic strokes. The threat of hemorrhage from the fragile collateral vessels that develop as compensation for carotid artery stenosis might prevent application of this effective therapy. Have there been any reports about stroke in patients with moyamoya disease who were treated with t-PA, perhaps in patients in whom the diagnosis of the underlying vasculopathy was revealed subsequently? Should moyamoya disease be considered to be a contraindication for t-PA administration?
Lea Pollak, M.D.
Assaf Harofeh Medical Center, 70315 Zerifin, Israel
lea.pollak@gmail. com Author/Editor Response
We appreciate the comments of both Derdeyn and Pollak regarding our review of moyamoya syndrome and moyamoya disease. Derdeyn points out that the natural history of North American adults with the “angiographic disorder” of moyamoya is unknown and that the typical North American adult with moyamoya is a woman in the fourth or fifth decade of life presenting with ischemic symptoms. In our small series of adult patients with moyamoya, ages ranged from 21 to 50 years at the time of their revascularization surgery and 19 of 20 patients were female. Twelve of these women presented with strokes (four of which were bilateral), and one presented with intracranial hemorrhage. We do not believe that our patients' history of ischemic symptoms or strokes can be considered benign. In the article by Hallemeier et al. referenced in Derdeyn's letter, the 5-year risk of recurrent stroke in the patients treated only medically was 65%. These two series show that adult patients with moyamoya do not have a “benign clinical course,” and we believe that at the completion of Derdeyn's NIH-funded natural-history study, his conclusions will probably be similar to ours.
In answer to Pollak's query regarding the use of thrombolytic therapy for stroke in moyamoya disease and moyamoya syndrome: we did not encounter any reports of such treatment in preparing our review. Moreover, many strokes in moyamoya appear to be caused by hemodynamic factors rather than by thrombus formation and embolization. Since patients with moyamoya have a risk of hemorrhage in areas of extensive formation of moyamoya collateral vessels, we would be reluctant to recommend thrombolytic therapy in a patient with moyamoya who has just had a stroke.
R. Michael Scott, M.D.
Edward R. Smith, M.D.
Children's Hospital Boston, Boston, MA 02115
edward.smith@childrens. harvard. edu
