Moyamoya disease in the midwestern United States.

There have been few investigations of moyamoya disease in the United States and no systematic description of the management practices or outcome from this population. The authors reviewed their experience with this disease to gain a better understanding and improve the treatment of patients with moyamoya disease in the United States. Over a 25-year period 30 patients with moyamoya disease have been treated at the University of Iowa. The cases were divided into patients who had classic, probable, and akin moyamoya disease. Results indicated that there was a bimodal age distribution and a female predominance of cases. In estimating the referral pattern of our institution, the authors determined that there were greater numbers of epidemiological characteristics than previously anticipated. Patients were treated either surgically or nonsurgically, and different management strategies were utilized in each of the major groups: superficial temporal artery to middle cerebral artery anastomosis and encephalodurosynangiosis in the surgical group; or antiplatelet, anticoagulation, or nonpharmacological intervention in the nonsurgical group. The authors conclude that there is a higher prevalence and incidence of moyamoya disease in the United States than previously reported and that there are some clinical characteristics of this disease that differ from the cases reported in southeast Asia. These differences may be due to genetic or environmental factors but can also be partly explained by the lower index of suspicion for this disease and, thus, a delay in or complete absence of the correct diagnosis.