Posterior Circulation Evaluation in Patients with Sickle Cell Anemia

Area of Science:

• Neurology
• Vascular Medicine
• Pediatric Hematology

Background:

• Transcranial Doppler (TCD) ultrasonography is established for identifying stroke risk in children with sickle cell anemia (SCA).
• Previous major studies on TCD in SCA populations did not include posterior circulation data.
• Understanding posterior circulation hemodynamics is crucial for a comprehensive stroke risk assessment in SCA.

Purpose of the Study:

• To characterize blood flow velocity patterns in the posterior circulation of adult SCA patients.
• To investigate the correlation between posterior circulation velocities and magnetic resonance imaging/angiography findings.
• To assess the prevalence of posterior circulation abnormalities in SCA.

Main Methods:

• Adult SCA patients underwent Transcranial Doppler (TCD) and Magnetic Resonance Imaging/Angiography (MRI/MRA).
• Time-averaged maximum mean (TAMM) velocity was recorded for the middle cerebral or internal carotid arteries.
• Maximum mean flow velocities in the posterior circulation (TAMMpost) were measured in the basilar, vertebral, and posterior cerebral arteries (PCAs).

Main Results:

• Mean TAMMpost velocities were significantly higher in SCA patients compared to healthy controls (P < .01).
• A positive correlation was observed between TAMMpost in posterior circulation arteries and TAMM in SCA patients.
• Stenosis in the posterior circulation was identified in only one SCA patient (right PCA).

Conclusions:

• SCA patients exhibit high blood flow velocities in the posterior circulation with a low frequency of stenosis.
• The clinical significance of elevated posterior circulation TCD velocities regarding stroke risk in SCA warrants further investigation.
• This study highlights the need for routine posterior circulation assessment in SCA patients using TCD.