Background: Moyamoya disease is a progressive occlusive arteriopathy of the terminal ICA and its branches, leading to the formation of unstable collateral vessels. The disease is found worldwide, and is associated with a number of predisposing conditions, termed moyamoya syndrome. Currently there is a paucity of data on the natural history of moyamoya disease in North America, especially the long-term outcome of pediatric moyamoya.
Objective: Our objectives were to determine the rate of recurrent TIA, ischemic stroke and intracerebral hemorrhage in patients presenting with pediatric Moyamoya disease and to assess long-term functional outcome.
Methods: This study was a retrospective chart review of 52 patients presenting with pediatric moyamoya disease. We included patients aged 18 or older with a diagnosis of moyamoya disease or syndrome. All patients had confirmatory baseline vascular imaging (MRA or CTA +/- cerebral angiography). Baseline demographic variables and annual vascular event recurrence risk were obtained from the records. Modified Rankin Score (MRS) at presentation and last follow-up were determined from clinical records.
Results: Of the original cohort, 34 patients were included for analysis. The mean age of the patients was 23.9 years. The mean age at presentation was 9 years (SD=4) with an average follow-up of 11.3 years (SD=5.1) for a total of 383 patient years. There was slight female predominance (1.4:1). Fifty percent of patients (17) presented with ischemic stroke. A total of 26 patients (76%) underwent surgery, with 7 (21%) requiring repeat surgery. The annual vascular recurrent event rate was 5.0% (19/383), which was not significantly different between surgical and non-surgical groups or between different moyamoya syndrome subtypes. Most of the recurrent events were TIA (annual recurrence 3.7%). There was no significant difference between initial MRS, MRS at last follow-up and mean change in MRS between surgical and non-surgical groups.
Conclusion: Our study is the largest North American natural history study of pediatric moyamoya. Our observations indicate that pediatric moyamoya in North America have low recurrent vascular event rates and long-term functional outcomes are good, even in conservatively managed patients.