Transcranial Doppler ultrasound velocities in a population of unstudied African children with sickle cell anemia

Abstract

Abstract The greatest burden of sickle cell anemia (SCA) globally occurs in sub‐Saharan Africa, where significant morbidity and mortality occur secondary to SCA‐induced vasculopathy and stroke. Transcranial Doppler ultrasound (TCD) can grade the severity of vasculopathy, with disease modifying therapy resulting in stroke reduction in high‐risk children. However, TCD utilization for vasculopathy detection in African children with SCA remains understudied. The objective was to perform a prospective, observational study of TCD findings in a cohort of children with SCA from the Democratic Republic of the Congo, Zambia, and Malawi. A total of 770 children aged 2–17 years without prior stroke underwent screening TCD. A study was scored as low risk when the time‐averaged maximum of the mean (TAMMX) in the middle cerebral artery or terminal internal carotid artery was 50 cm/s, conditional risk when 170–200 cm/s, and high risk when >200 cm/s. Low‐risk studies were identified in 604 children (78%), conditional risk in 129 children (17%), and high risk in three children (0.4%). Additionally, 34 (4%) were scored as having an unknown risk study (TAMMX <50 cm/s). Over the course of 15 months of follow‐up, 17 children (2.2%) developed new neurologic symptoms (six with low‐risk studies, seven with conditional risk, and four with unknown risk). African children with SCA in this cohort had a low rate of high‐risk TCD screening results, even in those who developed new neurologic symptoms. Stroke in this population may be multifactorial with vasculopathy representing only one determinant. The development of a sensitive stroke prediction bundle incorporating relevant elements may help to guide preventative therapies in high‐risk children.

Keywords

• Africa
• sickle cell anemia
• sickle cell disease
• transcranial Doppler ultrasound