Effects of hydroxyurea on cerebral blood flow in sickle cell anemia patients

Background: Stroke is a major cause of morbidity and mortality in patients with sickle cell anemia (SCA). Silent cerebral infarctions commonly occur and are poorly understood. Hence, evaluation and treatment of risk factors are the most important preventive measures. Hydroxyurea supplementation can be used to decrease the vascular complications of sickle cell anemia (SCA) and frequency of sickle cell crises. Transcranial Doppler ultrasonography (TCD) predicts the risk of cerebral infarction in patients with SCA. This study aims to explain the effect of hydroxyurea on the velocity of middle cerebral artery (MCA) in patients with SCA. Methods: Thirty patients with SCA were invited to participate in this study. They were divided into two study groups. Group (A) received no hydroxyurea treatment and were considered as a control group. Group (B) received hydroxyurea (Droxia 500mg capsule, 20mg/kg/day, given as a single dose for three months). Blood samples were obtained for hematological tests and hemoglobin electrophoresis; examination with TCD was then performed for both groups. Results: The systolic velocity of group A was significantly higher (150.2 ± 10.2 cm/second) than that in group B (119.8 ± 5.5 cm/second) (p < 0.05). At the same time, the diastolic and mean flow velocities of MCA were significantly higher (70.6 ± 11.9 cm/second and 118.4 ± 13.5 cm/second, respectively) in group A as compared to group B (40.1 ± 3.04 cm/second and 79.4 ± 5.5 cm/second) (p < 0.05). In addition, the hydroxyurea group showed a significantly smaller pulsatility index as compared to the control group. Conclusion: Hydroxyurea supplementation may decrease the risk of cerebral infarction in patients with SCA by decreasing the systolic, diastolic and mean flow velocity in MCA, as detected by TCD examination.