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

Pediatr Blood Cancer. 2015 Sep;62(9):1587-91. doi: 10.1002/pbc.25529. Epub 2015 Apr 1.

Abstract

Background: Sickle cell anaemia (SCA) is the leading genetic disorder in Nigeria. Elevated velocities ≥170 cm/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.

Objectives: To evaluate the effectiveness of hydroxyurea (HU) in reducing flow velocities in a cohort of Nigerian children with SCA and elevated velocities treated with HU.

Methods: An 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 ≥12 months of observation.

Results: Fifty 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.

Conclusion: HU appears to significantly reduce TCD velocities in Nigerian children with SCA and elevated velocities ≥170 cm/sec with beneficial effect on the haematological profile. HU may provide an effective approach to primary stroke prevention, particularly in Africa.

Keywords: TCD velocities; anaemia; hydroxyurea; sickle cell.

Publication types

  • Comparative Study
  • Observational Study

MeSH terms

  • Adolescent
  • Anemia, Sickle Cell / complications
  • Anemia, Sickle Cell / drug therapy
  • Anemia, Sickle Cell / physiopathology*
  • Anemia, Sickle Cell / therapy
  • Blood Cell Count
  • Blood Flow Velocity / drug effects*
  • Blood Transfusion
  • Cerebral Arteries / diagnostic imaging
  • Cerebrovascular Circulation / drug effects*
  • Child
  • Child, Preschool
  • Female
  • Hematocrit
  • Humans
  • Hydroxyurea / pharmacology*
  • Hydroxyurea / therapeutic use
  • Male
  • Nigeria
  • Risk Assessment
  • Stroke / etiology
  • Stroke / prevention & control
  • Treatment Refusal
  • Ultrasonography, Doppler, Transcranial*

Substances

  • Hydroxyurea