Flowchart of the study of patients from the newborn cohort with a history of abnormal velocities. Outcome of velocities after first normalization. Chronic transfusion was continued in 7 patients: 1 patient developed conditional velocities after initial normalization on transfusion, 2 patients with an identical donor are awaiting transplant, and 4 patients are scheduled for the switch to hydroxyurea. Chronic transfusion was stopped, and no new treatment introduced in 7 patients. Three of these had hypersplenism and were splenectomized, and it was decided to only observe the outcome. The parents of the 4 other patients refused the switch to hydroxyurea. After transfusion discontinuation, 3 of 7 patients (including 1 splenectomized) had reversion to abnormal TCDI and were placed again on transfusion, but 1 having a genoidentical cord blood donor was later transplanted. Transplant was performed in 17 patients who had a genoidentical donor. They were maintained on transfusion until transplant. All still have normal velocities posttransplant. Switch to hydroxyurea was prescribed in 45 patients (see the text).