Descriptive Study of Sickle Cell Disease Risk Factors and Magnitude in the Gulf Region Based on TCD Values

An observational study to identify the prevalence of Sickle Cell Disease (SCD) patients at high risk of stroke with abnormal Transcranial Doppler (TCD) who are eligible for transfusion therapy. The study consists of a baseline visit, 1 follow-up visit for patients with intermediate TCD, with a retrospective component of the past 3 years for all patients. The study will classify SCD patients according to risk of stroke yielded by TCD ultrasound results (low-risk=less than 170 cm/sec, moderate-risk=170-199 cm/sec, and high-risk=equal to or greater than 200cm/sec).