TCD in use with Sickle Cell Disease

Sickle Cell Disease (SCD) is one of the world’s most prevalent genetic diseases and the result of sickle-shaped deformations of the erythrocytes due to a genetic defect. Especially children with Sickle Cell Disease frequently have steno-occlusive lesions in large cerebral arteries and microangiopathic lesions, causing ischemic stroke and silent infarcts that impact on neurocognitive development and quality of life. The disease is mainly found in areas with widespread cases of malaria and occurs from a gene mutation in the children of infected people. Through migration, sickle cell anemia is spreading globally and has become a global public health issue.

TCD Sickle Cell Disease diagnosis, prognosis, and treatment

Stroke is one of the most serious complications that occur in children suffering from sickle cell disease (SCD), affecting approximately 5-10% of children with an incidence peak in the first decade of life. According to current knowledge the stroke recurrence is supposed to be 50-90% in untreated children.

Transcranial Doppler sonography (TCD) is the gold standard to assess blood flow velocities in the vessels of the Circle of Willis in SCD patients and predict the risk of stroke. TCD is highly recommended as a routine screening tool not only for Sickle Cell Disease diagnostics, but also for prognosis and for guiding therapy and treatment: exchange transfusions, hydroxyurea, allogeneic hematopoietic stem cell transplant, recently approved drugs and new therapeutic options (gene therapy, gene editing).
During an examination with the TCD, the user is given the opportunity to display the highest blood flow velocities and therefore determine the SCD quickly and easily.

Categorized TCD values to reduce stroke risk for children with Sickle Cell Disease

National SCD guidelines recommend that TCD screening should begin at age 2 years and continue annually until at least 16 to 18 years. Categorized TCD values in accordance with the STOP trial(s) (Adam et. al) has become widely used, such as Normal <= 170cm/s; Conditional – between 170 and 199 cm/s and Abnormal >= 200 cm/s. Actual recommendations e.g., of the American Society of Hematology guidelines (2020) suggests strategies for tracking TCD assessments and treatment of children with SCD and abnormal TCD measurements because these children are at extremely high risk for ischemic strokes.