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.