Introduction:
Stroke is among the most severe and common comorbidities experienced by children with sickle cell disease (SCD) with an estimated prevalence of 11% before the age of 20 years.14 Of these children with SCD who present with stroke, up to 43% are found to have moyamoya syndrome (MMS) on angiographic imaging.5 MMS is a cerebrovascular condition secondary to a pathologic condition, such as SCD, that is characterized by progressive stenosis of the arteries of the Circle of Willis and the development of a fragile network of small vessels that provide collateral blood flow. This network of capillary-sized blood vessels can fail to supply the necessary blood and oxygen to the brain, thus children with SCD with MMS are 5 times more likely to experience recurrent cerebrovascular events (CVEs – defined as strokes and transient ischemic attacks) compared to patients with SCD without MMS.5
Despite this increased risk of cerebral ischemia, treatment to prevent stroke that is directed at children with SCD-MMS has not been well studied. The current standard of care for stroke prevention is chronic transfusion therapy (CTT) to maintain a pre-transfusion sickle hemoglobin (HbS) level less than 30%.5,15 This has demonstrated reduced rates of cerebrovascular events in pediatric patients with SCD, although the risk of stroke in children with SCD-MMS still remains significant.1,13 Additionally, CTT is associated with complications such as iron overload, compliance issues, and treatment discontinuation.3
Direct and indirect surgical revascularization procedures have been shown to be effective in reducing recurrent events in idiopathic MMS; however, their role and effectiveness in the treatment for the combination of SCD-MMS have not been well characterized. Small, single-center, retrospective studies in pediatric patients with SCD-MMS have suggested that surgical revascularization decreases the risk of stroke with minimal perioperative risk.4,6,7,9,12,15-17 Despite promising results, these studies are limited by their small cohort size and lack of control groups. We sought to examine the outcomes in a larger cohort of children with SCD-MMS who underwent surgical revascularization in addition to CTT compared to those treated with CTT alone at two sickle cell treatment centers with active hematology and neurosurgery programs.