Transcranial Doppler in hemoglobin SC disease.

Area of Science:

• Neurology
• Hematology
• Pediatrics

Background:

• Stroke is a significant complication in sickle cell disease (SCD).
• Current stroke risk guidelines are primarily based on sickle cell anemia (SCA) and HbS/β-thalassemia genotypes.
• Limited data exist on transcranial Doppler (TCD) flow velocities in hemoglobin SC disease (HbSC).

Purpose of the Study:

• To compare cerebral blood flow, specifically TCD velocities, in pediatric patients with SCD stratified by genotype.
• To investigate potential differences in TCD velocity measurements between SCA and HbSC genotypes.

Main Methods:

• A cohort of 1,664 pediatric patients with SCD underwent TCD velocity screening.
• Time-averaged maximum mean velocity (TAMM) was measured in the middle cerebral artery (MCA) and internal carotid artery (ICA).
• Data were analyzed comparing TAMM values between SCA and HbSC genotypes.

Main Results:

• Abnormal velocities were not detected in the anterior cerebral artery (ACA).
• Mean TAMM in the ICA/MCA was significantly lower in HbSC patients (104.9 ± 19.3 cm/s) compared to SCA patients (134.5 ± 30.5 cm/s).
• TAMM showed a negative correlation with hemoglobin and hematocrit levels in both genotypes.

Conclusions:

• TCD velocities are significantly lower in pediatric HbSC patients compared to SCA patients.
• This suggests that current cut-off values for abnormal TCD velocities may not be appropriate for HbSC.
• Further research is needed to establish specific stroke risk assessment guidelines for HbSC genotype.