Background Transcranial Doppler (TCD) flow velocities predict stroke risk in children with sickle cell disease (SCD) and give a chance for primary stroke prevention. Elevated velocities ≥ 170 cm/sec are present in about one in three Nigerian children with SCD.1 Abnormal risk velocities and conditional risk (CR) velocities confer an annual stroke risk of 10% and 1–3% respectively. Nearly a quarter of children with CR will convert to abnormal risk2 but there is no recommended therapy for children with CR velocities.
Aims To evaluate the effectiveness of hydroxyurea therapy in reducing TCD velocities in children with SCD and TCD velocities ≥ 170 cm/sec.
Methods Children with HbSS disease and elevated velocities ≥ 170 cm/sec were prospectively followed up for a period of 18 months to document response to hydroxyurea (HU) therapy. TCD studies were performed at enrolment into the study and subsequently every 3 months for a period of 18 months.
Results Thirty-three children, 18 males and 15 females were enrolled. Twenty children (60.6%) and 13 (39.4%) had CR and abnormal risk velocities respectively. None of the caregivers consented to chronic blood transfusion for primary stroke prevention. Eighteen children (54.5%) received HU while 13 (45.5%) did not consent to any form of treatment for primary stroke prevention. Mean flow velocity at enrolment in the non-HU group was 189.5 cm/sec and 200.1 cm/sec in the HU group. At the end of 18 months, children on HU therapy had significantly lower TCD velocities 170.6 (SD=14.6) cm/sec (p < 0.001) while in the non-HU group, the velocities had significantly increased with a mean of 201.1 (SD=16.0) cm/sec (p = 0.003) compared with velocities at enrolment. Children with CR who did not receive HU were more likely to convert to abnormal risk (p < 0.001, 95% CI 1.373–5.847). None of the children developed a stroke.
Conclusion HU reduces flow velocities in children with SCD and elevated TCD velocities ≥170 cm/sec and reduces the risk of conversion from CR to abnormal risk velocities.
Lagunju IA, Sodeinde OO, Brown BJ, Akinbami FO, Adedokun BO. Transcranial Doppler ultrasonography in children with sickle cell anemia: clinical and laboratory correlates for elevated velocities. Journal of Clinical Ultrasound 2013 Oct 26 doi; 10.1002/jcu.22099
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