Factors Associated with Elevated Transcranial Doppler Ultrasound Velocities in Children With Sickle Cell Anemia in Mwanza, Tanzania

Background: Stroke occurs in 11% of patients with SCA before 20 years of age. In Northwestern Tanzania, the prevalence of stroke among children living with SCA under the age 15 years is 16.9%, of which might be attributed to the absence of routine screening for the risk of stroke by using Transcranial Doppler Ultrasound (TCD). Screening with TCD allows preventive measures such as chronic blood transfusion to be done which has led to the reduction of stroke by 92%. Methods: This was a prospective analytical cross sectional study which enrolled 267 SCA children aged 2 to 16 years attending Bugando Medical Centre Pediatric Sickle Cell Clinic from July 2019 to June 2020. Assessment of factors associated with elevated TCD included a clinical history of stroke in sibling, death in sibling, temperature, oxygen saturation in room air, blood pressure, hemoglobin level and total white blood cell count. TCD was done by accessing transtemporal window and recording the highest time average mean of maximum velocity (TAMMV) of major vessels mainly, middle cerebral artery (MCA) and distal internal carotid artery (dICA). Results: The median age of enrolled was 6.6 (IQR: 4-9) years. The prevalence of elevated TCD (> 170 cm/s) was found to be 21% (56/267). By multivariate logistic regression, low oxygen saturation in room air, p - value = 0.037, OR 1.08 [95% CI 1.00-1.17] and low hemoglobin level, p - value = 0.001, OR 1.76 [95% CI 1.26-2.45] were statistically significantly associated with elevated TCD among children living with SCA. Conclusion: The high prevalence of elevated TCD velocity, with low hemoglobin and low oxygen saturation in room air as associated factors under multivariate logistic regression, warrants routine TCD screening for children with SCA aged 2 to 16 years.