In patients who had a stroke attributable to hyper- coagulability from cancer who are anticoagulated, there is a paucity of data on the best treatment regi- men for these patients. Although low-molecular-weight heparin is often used in patients with cancer and stroke to prevent thromboembolic complications, the potential ben- efit on stroke prevention is unknown. 5.12. Sickle Cell Disease Recommendations for Sickle Cell Disease Referenced studies that support recommendations are summarized in online Data Supplement 49. COR LOE Recommendations In patients with sickle cell disease (SCD) and prior ischemic stroke or TIA, chronic blood transfusion(s) to reduce hemoglobin S to <30% of total hemoglobin is recommended for the prevention of recurrent ischemic In patients with SCD with prior ischemic stroke or TIA for whom transfusion therapy is not available or practical, treatment with hydroxyurea is reasonable for the prevention of recurrent ischemic stroke.659 665 Synopsis SCD is an autosomal recessive inherited hemoglobin- opathy that affects people predominantly of African or The normal flexible, round red blood cell is transformed into a sickle appearance. These sickled cells have abnormal interactions with the vascular wall endothelium, other blood cells, and clotting This can result in thrombosis or hypoperfusion Globally, >300000 children are born with SCD annually, most in sub-Saharan Africa.668 The pathophysiology of ischemic stroke in patients with SCD is large artery arteriopathy,669 believed to be caused by intimal hyperplasia related to repeated endothelial injury Progressive narrowing of arter- ies at the base of the brain can lead to cerebral vascu- lopathy or moyamoya syndrome, which can predispose a patient to both ischemic stroke and intracranial hemor- rhage. There are no randomized trials for antithrombot- ics for secondary stroke prevention in SCD. 