Stroke and conversion to high risk in children screened with transcranial Doppler ultrasound during the STOP study

Area of Science:

• Pediatric Hematology
• Neurology
• Medical Imaging

Background:

• Sickle cell anemia (SCA) poses a significant risk of stroke in children.
• Transcranial Doppler (TCD) is a non-invasive tool used to assess stroke risk in SCA.
• The Stroke Prevention Trial in Sickle Cell Anemia (STOP) aimed to evaluate stroke risk and prevention strategies.

Purpose of the Study:

• To evaluate the predictive value of transcranial Doppler (TCD) for stroke risk in children with sickle cell anemia (SCA).
• To analyze changes in TCD results over time with repeated testing in a high-risk SCA cohort.
• To report stroke outcomes in screened children who did not receive prophylactic transfusions.

Main Methods:

• A randomized multicenter controlled trial (STOP) screened over 2000 children with SCA (ages 2-16) using TCD.
• 130 high-risk children were enrolled in the randomized trial, with 5613 TCD studies evaluated from 2324 children.
• Repeated TCD testing was performed on 1215 children to monitor changes in cerebral blood flow velocity.

Main Results:

• Abnormal TCD results were significantly associated with a higher risk of stroke compared to normal, conditional, or inadequate TCD findings.
• Conditional TCD results indicated a higher stroke risk than normal TCD findings.
• During repeated TCD screening, 9.4% of children transitioned to an abnormal TCD status, with younger age and higher initial flow velocities being predictors of this conversion.

Conclusions:

• TCD screening is a valuable tool for identifying children with SCA at high risk of stroke.
• Cerebral blood flow velocity assessed by TCD can change over time, necessitating regular monitoring.
• Younger children and those with elevated initial TCD velocities are more prone to developing abnormal TCD findings, highlighting the need for vigilant follow-up.