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Transcranial Doppler Velocities among Sickle Cell Disease Patients in Steady State
Khaled Salama1, Rasha Rady1, Rania H Hashem2
1Department of Pediatrics, Pediatric Hematology & Bone Marrow Transplantation (BMT) Unit, Cairo University, Cairo, Egypt.
Insights
Transcranial Doppler (TCD) screening helps identify children with sickle cell disease at risk for stroke. Hemolysis indicators, like bilirubin and reticulocyte count, correlate with elevated TCD velocities in these patients.
Area of Science:
- Neurology
- Hematology
- Pediatrics
Background:
- Sickle cell disease (SCD) poses a significant risk of stroke in children.
- Transcranial Doppler (TCD) ultrasonography is a key screening tool for identifying at-risk SCD patients.
- Understanding TCD velocity patterns in steady-state SCD is crucial for stroke risk stratification.
Purpose of the Study:
- To investigate Transcranial Doppler (TCD) velocities in steady-state pediatric patients with sickle cell anemia (Hb SS) and sickle beta-thalassemia (Hb S/β-thal).
- To explore the correlation between hemolysis indicators and TCD velocities in these SCD patient cohorts.
- To assess the relationship between hemoglobin levels and TCD velocities in steady-state SCD.
Main Methods:
- A cross-sectional study involving 78 steady-state pediatric SCD patients (31 Hb SS, 47 Hb S/β-thal).
- TCD velocity assessments were performed according to the Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol.
- Statistical analysis examined correlations between TCD velocities, hemolysis markers (total bilirubin, reticulocyte count), and hemoglobin levels.
Main Results:
- TCD velocities were comparable between Hb S/β-thal and Hb SS patients.
- Significant positive correlations were observed between total bilirubin and reticulocyte counts with TCD velocities in Hb S/β-thal patients.
- Negative correlations were found between hemoglobin levels and TCD velocities in the right anterior cerebral artery (ACA) and right distal internal carotid artery (dICA).
Conclusions:
- Hemolysis indicators are associated with elevated TCD velocities, suggesting an increased stroke risk in steady-state SCD patients.
- While Hb F may mitigate disease severity, hemolysis appears to be a critical factor for TCD velocity elevation and stroke risk in SCD.
- TCD screening remains vital for identifying children with SCD who require closer monitoring and potential intervention to prevent stroke.
Abstract:
Transcranial Doppler (TCD) screening is an established tool to identify children with sickle cell disease at high risk of stroke. Our objective was to study TCD velocities among sickle cell disease patients while in a steady state. This cross-sectional study included 78 steady state sickle cell disease patients [31 Hb SS (βS/βS) (sickle cell anemia), 47 Hb S/β-thalassemia (HBB: c.20A>T/β-thal)], attending the Pediatric Hematology Clinic at Cairo University Children's Hospital, Cairo, Egypt. All patients underwent TCD velocity assessment as per the Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol. In our cohort, TCD velocities were comparable among Hb S/β-thal vs. SS patients. Hemolysis indicators correlated significantly to TCD velocities in Hb S/β-thal patients; positive correlation was found between total bilirubin level and right middle cerebral artery (MCA) and right distal internal carotid artery (dICA) TCD velocities (r = 0.428, p = 0.00, r = 0.360, p = 0.01), respectively as well as between reticulocyte count and right MCA, right dICA and right anterior cerebral artery (ACA) TCD velocities (r = 0.424, p = 0.01), (r = 0.40, p = 0.00), (r = 0.303, p = 0.04), respectively. On the other hand, statistically significant negative correlations were found between hemoglobin (Hb) level and right ACA, right dICA TCD velocities (r = -0.290, p = 0.05), (r = -0.324, p = 0.03). Although Hb F is considered an ameliorating factor for disease severity; hemolysis stands as an indicator of risk for TCD velocity elevation, and in turn, risk for stroke among sickle cell disease patients.
