# Clinical and Laboratory Correlates of Cerebral Blood Flow Velocities and Risks for Stroke Among Steady-State Sickle Cell Anemia Children: A Cross-Sectional Study

## TL;DR

This study finds that age, height, blood parameters, and stunting are linked to increased stroke risk in children with sickle cell anemia.

## Contribution

The study identifies specific clinical and lab parameters that correlate with cerebral blood flow velocity and stroke risk in children with sickle cell anemia.

## Key findings

- Stunted children had higher abnormal blood flow velocities compared to normal-height children.
- White blood cell count and packed cell volume are significantly associated with stroke risk.
- Age and height negatively correlate with both blood flow velocity and stroke risk.

## Abstract

Background

Transcranial Doppler (TCD) ultrasound (US) is commonly used to assess cerebral blood flow velocity and identify abnormal flow patterns. Additionally, clinical and laboratory parameters could be useful for the early detection of sickle cell anemia (SCA) patients who are prone to developing stroke, especially in low-income settings.

Objectives

This study aims to correlate clinical and laboratory parameters with the risk of stroke according to TCD values in children with steady-state sickle cell anemia.

Methods

This study used a cross-sectional observational design, with study participants (steady-state SCA children, aged 2-14 years) recruited consecutively. The demographic details, general examination findings, frequency of crisis and blood transfusions, and duration of hydroxyurea usage, as well as the participants’ weight, height, and nutritional indices, were recorded. The time-average mean of maximum velocity (TAMMV) was determined via transcranial Doppler imaging US of the middle and anterior cerebral arteries (MCAs and ACAs) on both sides of the head. The full blood count was determined via a hematology autoanalyzer, and an enzyme-linked immunosorbent assay (ELISA) kit was used to measure fetal hemoglobin. Statistical Package for Social Sciences software for Windows version 26 (IBM SPSS Inc., Chicago, IL) was used to determine the frequency, mean and standard deviation, associations, and correlations. The level of statistical significance was set at P < 0.05.

Results

A total of 110 SCA children were studied. The TAMMVs for normal height and stunted subjects were 133.79 ± 27.32 and 154.74 ± 37.18 cm/s, respectively (t = 2.138, p = 0.035), and the prevalence of abnormal velocity was significantly greater among stunted subjects (c2 = 6.25, p = 0.044). Age, weight, and height have significant negative correlations with TAMMV and p-values of 0.003, 0.009, and 0.002, respectively, whereas age and height have significant negative correlations with the risk of stroke (p-values of 0.048 and 0.046, respectively).

An increased WBC count was significantly associated with an increased risk of stroke (p = 0.000), whereas a decreased PCV significantly increased the risk of stroke (p = 0.009). WBC counts were correlated with the TAMMV (r = .227, p = 0.017) and risk of stroke (r = .390, p = 0.001), whereas PCV values were negatively correlated with the TAMMV (r = -.197, p = 0.039) and risk of stroke (r = -.286, p = 0.002). HbF levels were not associated with or correlated with the TAMMV or risk of stroke. The frequency of blood transfusion and crisis was not significantly associated with or correlated with TAMMV or the risk of stroke. Additionally, the duration of hydroxyurea usage was not significantly associated with TAMMV but was correlated with the risk of stroke (r = .195, p = 0.042).

Conclusions

Age, height, PCV, WBC count, and stunting status are significantly associated with and correlated with TAMMV and the risk of stroke. In children aged 2-5 years, stunted, with high WBC count and low PCV, TCD examination should be mandatory.