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The use of transcranial ultrasonography to predict stroke in sickle cell disease
Insights
Transcranial Doppler ultrasonography can identify children with sickle cell disease at high risk for stroke. This allows for targeted transfusion therapy to prevent cerebral infarction, making primary stroke prevention achievable.
Area of Science:
- Pediatric Neurology
- Hematology
- Medical Imaging
Background:
- Stroke, particularly cerebral infarction, is a significant cause of disability and death in children with sickle cell disease.
- Identifying high-risk individuals is crucial for implementing effective primary stroke prevention strategies.
- Transcranial Doppler ultrasonography measures intracranial arterial blood flow velocity, indicating potential narrowing linked to stroke risk.
Purpose of the Study:
- To prospectively evaluate the efficacy of transcranial Doppler ultrasonography in identifying children with sickle cell disease at high risk for cerebral infarction.
- To determine if abnormal flow velocities predict future stroke events.
Main Methods:
- Prospective measurement of cerebral blood flow velocity using transcranial Doppler ultrasonography in children and young adults with sickle cell disease.
- Classification of results as normal or abnormal based on middle cerebral artery flow velocity (≥170 cm/s).
- Follow-up to identify clinically apparent first cerebral infarction as the primary endpoint.
Main Results:
- Seven strokes occurred in 190 patients over a mean follow-up of 29 months.
- Abnormal ultrasound results were found in 23 patients, while 167 had normal results.
- Six of the seven strokes occurred in the 23 patients with abnormal ultrasound findings, yielding a relative stroke risk of 44 (95% CI, 5.5–346).
Conclusions:
- Transcranial ultrasonography is effective in identifying children with sickle cell disease who are at the highest risk for cerebral infarction.
- Regular ultrasound screening and selective transfusion therapy can achieve primary stroke prevention in this population.
Background:
Stroke, especially cerebral infarction, is a major cause of morbidity and mortality in children with sickle cell disease. Primary prevention of stroke by transfusion therapy may be feasible if there is a way to identify the patients at greatest risk. Transcranial Doppler ultrasonography can measure flow velocity in the large intracranial arteries. The narrowing of these arteries, which leads to cerebral infarction, is characterized by an increased velocity of flow.
Methods:
Using transcranial Doppler ultrasonography, we prospectively measured the velocity of cerebral blood flow in children and young adults being followed because of sickle cell disease. The results were classified as either normal or abnormal on the basis of the highest velocity of flow in the middle cerebral artery. Abnormal velocity was defined as a flow greater than or equal to 170 cm per second, a definition determined by post hoc analysis to maximize the predictive success of the test. The end point was a clinically apparent first cerebral infarction.
Results:
Two hundred eighty-three transcranial ultrasound examinations were performed in 190 patients with sickle cell disease (age at entry, 3 to 18 years). After an average follow-up of 29 months, cerebral infarction was diagnosed in seven patients. In 23 patients the results of the ultrasound examinations were abnormal, and in 167 patients they were normal. The clinical and hematologic characteristics of the two groups were similar, but six of the seven strokes occurred among the 23 patients with abnormal ultrasound results (P less than 0.00001 by Fisher's exact test). In this group, the relative risk of stroke was 44 (95 percent confidence interval, 5.5 to 346).
Conclusions:
Transcranial ultrasonography can identify the children with sickle cell disease who are at highest risk for cerebral infarction. Periodic ultrasound examinations and the selective use of transfusion therapy could make the primary prevention of stroke an achievable goal.