Transcranial Doppler (TCD) is used to detect children with sickle cell anemia (SCA) who are at risk for stroke, and transfusion programs significantly reduce stroke risk in patients with abnormal TCD. We describe the predictive factors and outcomes of cerebral vasculopathy in the Cré teil newborn SCA cohort (n ‫؍‬ 217 SS/ S␤ 0 ), who were early and yearly screened with TCD since 1992. Magnetic resonance imaging/magnetic resonance angiography was performed every 2 years after age 5 (or earlier in case of abnormal TCD). A transfusion program was recommended to patients with abnormal TCD and/or stenoses, hydroxyurea to symptomatic patients in absence of macrovasculopathy, and stem cell transplantation to those with human leukocyte antigengenoidentical donor. Mean follow-up was 7.7 years (1609 patient-years). The cumulative risks by age 18 years were 1.9% (95% confidence interval [95% CI] 0.6%-5.9%) for overt stroke, 29.6% (95% CI 22.8%-38%) for abnormal TCD, which reached a plateau at age 9, whereas they were 22.6% (95% CI 15.0%-33.2%) for stenosis and 37.1% (95% CI 26.3%-50.7%) for silent stroke by age 14. Cumulating all events (stroke, abnormal TCD, stenoses, silent strokes), the cerebral risk by age 14 was 49.9% (95% CI 40.5%-59.3%); the independent predictive factors for cerebral risk were baseline reticulocytes count (hazard ratio 1.003/L ؋ 10 9 /L increase, 95% CI 1.000-1.006; P ‫؍‬ .04) and lactate dehydrogenase level (hazard ratio 2.78/1 IU/mL increase, 95% CI1.33-5.81; P ‫؍‬ .007). Thus, early TCD screening and intensification therapy allowed the reduction of stroke-risk by age 18 from the previously reported 11% to 1.9%. In contrast, the 50% cumulative cerebral risk suggests the need for more preventive intervention. (Blood. 2011;117(4):1130-1140)

Key Points• Baseline hemoglobin levels lower than 7 g/dL, acute anemia, and extracranial internal carotid stenosis are significant and independent risk factors for SCI in SCA.Early transcranial Doppler (TCD) screening of the Créteil sickle cell anemia (SCA)-newborn cohort, and rapid initiation of transfusion programs, resulted in successful prevention of overt strokes, but a high cumulative risk of silent cerebral infarcts (SCI) remained, suggesting that TCD screening does not identify all patients with SCA at risk for SCI. We hypothesized that episodes of hypoperfusion/hypoxia, as observed during acute chest syndromes or acute anemic events (AAE), and extracranial internal carotid artery (eICA) stenoses, detectable via submandibular Doppler sonography and cervical magnetic resonance angiography (MRA), could also be risk factors for SCI. This study includes 189 stroke-free patients with SCA from the Créteil newborn cohort (1992-2010) followed longitudinally by magnetic resonance imaging/MRA, including cervical MRA at the last assessment. All patients with abnormal TCD and/or intracranial stenoses were placed on a transfusion program. Mean follow-up was 9.9 years (range, 2.2-19.9 years; 1844 patient-years). Annual rates of clinical events were calculated. The cumulative risk for SCI was 39.1% (95% confidence interval [CI], 23.5%-54.7%) by age 18 years, with no plateau. We confirm that baseline hemoglobin level lower than 7 g/dL before age 3 years is a highly significant predictive risk factor for SCI (hazard ratio, 2.97; 95% CI, 1.43-6.17; P 5 .004). Furthermore, we show that AAE rate (odds ratio, 2.64 per unit increase; 95% CI, 1.09-6.38; P 5 .031) and isolated eICA stenosis (odds ratio, 3.19; 95% CI, 1.18-8.70; P 5 .023) are significant and independent risk factors for SCI. (Blood. 2015;125(10):1653-1661

Stroke is predicted by abnormally high cerebral velocities by transcranial doppler (TCD).

Key Points Children with normalized TCD on transfusions were safely switched to hydroxyurea treatment, but trimestrial Doppler follow-up is required. Allogeneic transplant allowed the safe stop of transfusions in all patients, even in those with abnormal velocities before transplant.