Transcranial Doppler screening in Nigerian children with sickle cell disease: A 10‐year longitudinal study on the SPPIBA cohort

Abstract

Background Primary stroke prevention programmes for children with sickle cell disease (SCD) have been shown to be feasible interventions in resource‐poor countries. Different hydroxyurea (HU) regimens have been utilised in ameliorating the severity of SCD. Objective To determine the long‐term outcomes of the stroke prevention programme for children with SCD in Ibadan (SPPIBA), Nigeria. Methods A longitudinal study of 396 children with haemoglobin SS disease who had been on the stroke prevention programme for a minimum period of 5 years. All enrollees had nonimaging TCD performed at baseline and thereafter 3‐monthly or annually. Children with TCD velocities ≥170 cm/s were treated with HU by dose‐escalation regimen. Results The mean age at first TCD examination was 102 ± 46.7 months and the period of follow‐up ranged from 5 to 10 years (mean = 7.2 ± 1.7). Time to significant decline in TCD velocities ranged from 5 to 35 months, (median = 10.0 months). The minimum dose of HU required to achieve significant decline in TCD velocities ranged from 15 to 31 mg/kg/day, mean 23.7 (±3.9). HU dose escalation beyond 20 mg/kg/day was required to attain significant reductions in the time‐averaged mean of maximal velocities (TAMMV) in 69.1% of the cases. Two stroke events occurred giving a stroke incidence of 0.08 per 100 patient‐years. Conclusion The majority of Nigerian children with SCD and elevated TCD velocities achieved significant decline in TAMMV within the first year of HU therapy but on higher doses of HU. It might be important to individualise HU doses for optimal outcomes in primary stroke prevention.

Evidence-based interventions for reducing sickle cell disease-associated morbidity and mortality in sub-Saharan Africa: A scoping review

“…76 Lagunju et al and Ambrose et al, in their studies, demonstrated a reduction in TCD velocities following hydroxyurea therapy. 33,56,57,60 Abnormal or elevated TCD velocity has been linked with increased risk of stroke incidence. Studies in high-income settings have shown reduced stroke incidence in patients with elevated TCD velocities following blood transfusion (STOP trials).…”

“…Hydroxyurea (HU) therapy effectively reduced SCD-related adverse events among children, especially stroke incidence and VOC. 29,31,[33][34][35][54][55][56][57][58][59][60][61] In addition, HU therapy showed favourable haematological indices and led to a decline in mortality among children who received it. 61 Furthermore, HU therapy showed low risk of haematological harm.…”

Transcranial doppler velocities in a large healthy population of African children

“…Furthermore, as a result of its favorable attributes and the lack of alternate, available neuroimaging techniques, TCD is increasingly being used in the management of African children with sickle cell disease, obstructive hydrocephalus, sinus venous thrombosis, meningitis and cerebral malaria [ [5] , [6] , [7] , [8] , [9] , [10] ]. The interpretation of TCD examinations in this context is particularly problematic given the complete absence of normative data in African children.…”

Brain volume in Tanzanian children with sickle cell anaemia: A neuroimaging study

“…The prevalence of overt stroke in people with SCA living in African countries is 3%–17%, with children most commonly affected 2,3 . Transcranial Doppler screening and hydroxycarbamide (hydroxyurea) reduces overt stroke risk in African children 4 . However, little is known about the effect of silent cerebral infarction (SCI), which is also common in patients with SCA, 5 and may be the result of chronic, repetitive injury due to hypoxic or ischaemic exposure.…”

“…2,3 Transcranial Doppler screening and hydroxycarbamide (hydroxyurea) reduces overt stroke risk in African children. 4 However, little is known about the effect of silent cerebral infarction (SCI), which is also common in patients with SCA, 5 and may be the result of chronic, repetitive injury due to hypoxic or ischaemic exposure. Similar mechanisms may underlie structural brain changes, including volumetric deficits.…”