Researchers conducted a study to evaluate the incidence of ischemic stroke among patients who had previously participated in trials related to stroke prevention in sickle cell disease (SCD). The results of the study were reported in the American Journal of Hematology.

The study, termed the “post-STOP study,” included children 2 to 16 years of age with homozygous SCD or SCD-S-beta-0-thalassemia. All patients in the post-STOP study had previously been enrolled in the Stroke Prevention Trial in Sickle Cell Anemia (STOP), the Optimizing Primary Stroke Prevention in Sickle Cell Anemia (STOP 2) study, or both.

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A key protocol that emerged from the STOP trial, referred to as the STOP protocol, was the use of annual transcranial Doppler ultrasound (TCD) screening in conjunction with chronic red cell transfusions if TCD results were abnormal.

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In the post-STOP study, 2808 patients were evaluated who had no history of stroke at the time of study initiation. The median duration of follow-up was 10.3 years (range, 0-15.4). The median age of patients at the beginning of the post-STOP study was 10.4 years (range, 2.0-23.2).

During the Post-STOP study, 60 ischemic strokes occurred, affecting 2.1% of the patients. This translated to a rate of first ischemic stroke of 0.24 per 100 patient-years.

The researchers determined that 63% of the initial ischemic strokes that occurred during the post-STOP study were associated with lack of adherence to the STOP protocol. In some cases, there was insufficient administration of chronic red cell transfusions after an abnormal TCD screening. A screening failure occurred with 23 cases of stroke. Of these patients, 17 had not received TCD screening at all during the post-STOP study before a stroke.

The researchers noted that even adequate usage of the STOP protocol would not have prevented all cases of ischemic stroke in the post-STOP study. However, the authors wrote, “this study indicates that there remain substantial opportunities for ischemic stroke prevention by more complete implementation of the STOP protocol.”


1.     Kwiatkowski JL, Kanter J, Fullerton HJ, et al. Ischemic stroke in children and young adults with sickle cell disease in the post-STOP era [published online September 6, 2019]. Am J Hematol. doi:10.1002/ajh.25635