Hydroxyurea lowers transcranial Doppler flow velocities in children with sickle cell anaemia in a Nigerian cohort

BackgroundSickle cell anaemia (SCA) is the leading genetic disorder in Nigeria. Elevated velocities 170cm/sec occur in about a third of Nigerian children with SCA. Chronic blood transfusion for stroke prevention is faced with a myriad of challenges in our practice. ObjectivesTo evaluate the effectiveness of hydroxyurea (HU) in reducing flow velocities in a cohort of Nigerian children with SCA and elevated velocities treated with HU. MethodsAn observational study was carried out on a cohort of Nigerian children with SCA and elevated velocities identified on routine transcranial Doppler (TCD) screening. HU was recommended in those with TCD velocities 170cm/sec as stipulated in our hospital protocol. Outcomes were compared after 12months of observation. ResultsFifty children with elevated TCD velocities were studied; 31 consented to HU therapy and 19 declined. Children on HU showed a statistically significant decline in mean velocities from 199.7 [17.1]cm/sec to 165.8 [20.7]cm/sec (P<0.001) with a significant increase in mean packed cell volume from 21.1 [3.4] to 25.0 [2.8]%. Children without treatment had a significant rise in mean velocities from 190.2 [10.8]cm/sec to 199.7 [14.9]cm/sec (P=0.003). Children with conditional risk velocities on HU were less likely to convert to abnormal risk (P<0.001). Two stroke events occurred, one in each group. No adverse effects of HU were recorded in the cohort. ConclusionHU appears to significantly reduce TCD velocities in Nigerian children with SCA and elevated velocities 170cm/sec with beneficial effect on the haematological profile. HU may provide an effective approach to primary stroke prevention, particularly in Africa. Pediatr Blood Cancer 2015;62:1587-1591. (c) 2015 Wiley Periodicals, Inc.