Survival free of detection of new silent cerebral infarcts in children with SCD while on transfusion therapy for secondary stroke prophylaxis. Participants with progressive silent infarctions only, stratified for the absence (solid line) or the presence (dashed line) of progressive cerebral vasculopathy while receiving chronic blood transfusion therapy. Vertical lines represent censored cases. Median progressive silent infarction only interval was 3.6 years for those with progressive vasculopathy versus median progressive silent infarct–free interval not reached for those without progressive vasculopathy (Mantel-Cox log-rank, P = .017).