Transcranial Doppler Screening in a Regional Care Network for Sickle Cell Disease in the United Kingdom.

The risk of stroke in children screened with transcranial Doppler ultrasound in the United Kingdom is not known. We evaluated a clinician-led program using a risk assessment modified from the STOP protocol. High-risk classification included abnormal velocities in the anterior cerebral artery, and single abnormal scan if initial velocity >220 cm/s (high abnormal) or if preceded by at least 2 conditional scans. In total, 1653 scans were performed in 542 children, followed for 2235 patient-years. Fifty-eight (10.7%) high-risk subjects were identified, including 18 (31%) with high abnormal, and 15 (26%) with previous conditional scans. In 2 (3%), abnormal velocity was restricted to the anterior cerebral artery. The estimated proportion of children at high risk, scanned before 6 years of age was >20%. There were 4 cases of acute ischemic stroke (AIS) and 2 of acute hemorrhagic stroke. The incidence of all stroke, AIS, and acute hemorrhagic stroke were 0.27, 0.18, and 0.09 per 100 patient-years, respectively. The proportion of children at high risk is higher than most previous estimates, partly as a result of our modified risk assessment. About 2 children per 1000 screened with transcranial Doppler ultrasound progress to AIS.

Deferasirox for iron chelation in multitransfused children with sickle cell disease; long-term experience in the East London clinical haemoglobinopathy network.

Deferasirox (DFX) has been licensed for iron chelation in patients with sickle cell disease (SCD), but there is limited data on its long-term efficacy and safety in children. This retrospective study included 62 regularly transfused children managed in the East London and Essex Clinical Haemoglobinopathy Network (mean age 9.2 ± 3.2 yr). Efficacy measurements consisted of monthly serum ferritin (SF) and annual R2 MRI-estimated liver iron concentration (LIC), and safety markers included serum creatinine and alanine aminotransferase (ALT). The mean duration of DFX treatment was 2.5 ± 1.4 yr, and mean dose at 36 months was 25 mg/kg/d. Mean SF at initiation of treatment was 2542 ± 952 ng/mL and increased to 4691 ± 2255 ng/mL at 36 months (P = 0.05). Mean LIC on first scan was 10.3 mg/g dry weight and did not decrease significantly on follow-up scans. There was a significant correlation between relative change in LIC and in SF (R(2) = 0.66, P < 0.001). Reversible transaminitis episodes, probably due to drug-induced hepatitis, were noted in 53% of patients. Responses to an adherence and acceptability questionnaire indicated that more than 50% of children had difficulties in taking DFX, commonly because of unpleasant taste. Our results show that more than 50% of children with SCD have inadequate control of iron overload with DFX. It is not clear whether this is because of frequent dose interruptions, poor tolerability and adherence, or poor efficacy of the drug. We recommend further studies to confirm these findings and to optimise iron chelation in this population.

Cervical carotid artery disease in sickle cell anemia: clinical and radiological features.

Cervical internal carotid artery (cICA) occlusion is a recognized cause of acute ischemic stroke (AIS) in sickle cell disease (SCD), but the associated clinical and radiologic features are not well described. We reviewed data on cervical magnetic resonance angiography (cMRA) performed prospectively in 67 patients (55 children) for indications including transcranial Doppler (TCD) abnormalities, AIS, or previous AIS. cICA lesions were seen in 10 (15%) patients, including 4 of 7 patients presenting with AIS, and appear to have been missed on first presentation in 4 of 10 patients with previous AIS. Radiologic features in 7 patients were consistent with dissection. In 2 patients, there was strong clinical and radiologic evidence for thromboembolic AIS, and this was also considered possible in 4 other patients. Three of the 4 AIS patients were anticoagulated acutely, and the nontreated patient had recurrent, probably thromboembolic, AIS. TCD findings were variable, but in 4 patients there were high velocities in the cerebral vessels contralateral to the cICA stenosis. We suggest that all patients with AIS should have cMRA during acute evaluation to identify cICA occlusions that may require anticoagulation. Routine screening of children with SCD should also include evaluation of neck vessels by carotid Doppler followed by cMRA if a cervical vascular lesion is suspected.