Long-term follow-up of pediatric sickle cell disease patients with abnormal high velocities on transcranial Doppler.

Cerebral arteriopathy can be detected in children with sickle cell disease (SCD) by transcranial Doppler (TCD). Abnormally high velocities are predictive of high stroke risk, which can be reduced by transfusion therapy. We report the results of the screening of 291 SCD children followed in our center, including the clinical and imaging follow-up of 35 children with abnormal TCDs who were placed on transfusion therapy. We postulated that patients with normal MRA findings and abnormal TCD velocities that normalized on a transfusion program could be safely treated with hydroxyurea (HU). We report their outcome (median follow-up of 4.4 years). Of 13 patients with normalized velocities on transfusion, 10 had normal MRAs, and transfusion therapy was stopped and HU begun. Four of these ten patients redeveloped high velocities off transfusion, so currently only six remain transfusion-free. Six other transplanted patients remain transfusion-free. Abnormal TCD velocities detect a high-risk group, justifying the research for suitable transplant donors. Multicenter studies comparing HU therapy to long-term transfusion might help identify which patients can avoid transfusion and its complications while avoiding vasculopathy.