Long-term outcomes of nonsurgical management alone for adult patients with ischemic moyamoya disease without cerebral misery perfusion: combined analyses of two prospective cohorts

INTRODUCTION: The most appropriate method to manage adult patients with ischemic-onset moyamoya disease (MMD) without hemodynamic compromise remains undetermined. This study aimed to elucidate the long-term (5- to 10-year) clinical, angiographic, and cognitive outcomes of nonsurgical management alone (including a reduction in atherosclerotic burden by medical treatments and antiplatelet therapy) for adult patients with ischemic MMD without cerebral misery perfusion through combined analyses of two prospective cohorts with the same inclusion criteria. METHODS: The first cohort (71 patients) achieved the 10-year follow-up. The second cohort (55 patients) was followed for ≥ 5 and ≤ 10 years. Whether further cerebrovascular events had developed was determined during follow-up. To determine the development of angiographic disease progression and cognitive decline, patients underwent magnetic resonance angiography (MRA) and neuropsychological testing, respectively, at inclusion as well as at last follow-up during or at the end of the 10-year follow-up. Additional MRA was performed if any further cerebrovascular events had developed. RESULTS: In a combination of the two cohorts, the 10-year cumulative further cerebrovascular event rate was 9.5%, the incidence of angiographic disease progression was significantly higher in patients with further cerebrovascular events (100%) than in patients without (7%; p <0.001), and the incidence of clopidogrel administration at last follow-up during or at the end of the 10-year follow-up was significantly higher in patients with declined cognition (100%) than in those without (21%; p <0.001). Due to the small number of patients with further cerebrovascular events or declined cognition, multivariate statistical analysis was not performed. CONCLUSION: The 10-year cumulative further cerebrovascular event rate was < 10% and angiographic disease progression may cause further cerebrovascular events in adult patients with ischemic MMD without cerebral misery perfusion who received nonsurgical management alone, including a reduction in atherosclerotic burden by medical treatment and antiplatelet therapy. Cognitive declines may develop in such patients without further cerebrovascular events.