Although multiple case series and meta-analyses of varying sizes and quality exist, many include both patients with moy- amoya disease and those with moyamoya syndrome, as well as pediatric and adult patients. Few address second- ary prevention of ischemic stroke specifically or issues of ethnic/geographic variability in general. Selection bias and publication bias are significant concerns. The resulting low-quality evidence related to the second- ary prevention of ischemic stroke precludes any strong recommendations. Recommendation-Specific Supportive Text 1. Within the realm of surgery, there is considerable controversy as to what constitutes the best sur- gical option, direct superficial temporal artery to middle cerebral artery bypass or an indirect bypass procedure such as encephaloduroarteriosynangio- sis or encephalomyosynagiosis. The differences in surgical technique even within the broad catego- ries of direct and indirect bypass, the frequent use of combined procedures, and the heterogeneity of the patient population make it difficult to draw robust conclusions about the superiority of one procedure over another. Again, there are no pro- spective RCTs to inform recommendations in this area. Although several meta-analyses and case series favor direct over indirect bypass,391 395 all but 1 of these studies combined both hemorrhagic and ischemic patients. A propensity score matched analysis on 220 adult patients with ischemic-type moyamoya disease showed that direct bypass was superior to indirect bypass for the prevention of In this series, however, the pri- mary end point of recurrent stroke was defined as both ischemic and hemorrhagic events. In contrast, and a retrospective mul- reported no difference between direct and indirect modalities. 2. 