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Keywords:

  • platelets;
  • sickle cell anemia;
  • stroke

Abstract

Background

Overt stroke in sickle cell anemia (SCA) is associated with intracranial stenosis and thrombus formation. Platelet activation is critical for thrombus formation.

Procedure

Platelet activation studies were performed in 50 subjects: 18 SCA patients with history of stroke or abnormal transcranial Doppler (TCD) and intracranial stenosis seen by magnetic resonance angiogram (MRA), 7 SCA patients with history of stroke or abnormal TCD but no intracranial stenosis, 13 SCA patients with no history of stroke or abnormal TCD, and 12 healthy African-Americans.

Results

Of the 18 patients with intracranial stenosis, 11 (61%) had evidence of the moyo-moya phenomenon on MRA. SCA children with intracranial stenosis had a significantly greater total white cell count compared to both healthy African-American controls and SCA patients in the steady-state (P < 0.001). In addition, SCA patients with history of stroke or abnormal TCD had a significantly higher platelet count compared to healthy African-American controls (P < 0.002). The percentage of platelet surface P-selectin expression was significantly greater in patients with intracranial stenosis compared to the other groups (P < 0.05), particularly in individuals that did not have the moya-moya phenomenon seen on MRA.

Conclusion

Stroke with intracranial stenosis is associated with increased platelet activation in sickle cell anemia, and further investigation is needed on the role of anti-platelet agents in this high-risk population. Pediatr Blood Cancer 2013; 60: 1192–1197. © 2013 Wiley Periodicals, Inc.