Effect of chronic transfusion therapy on progression of neurovascular pathology in pediatric patients with sickle cell anemia.

BACKGROUND Chronic blood transfusion (CBT) is currently the standard of care for primary and secondary stroke prevention in children with sickle cell anemia (SCA). However, the effect of CBT on cerebrovascular pathology is not well known. METHODS We reviewed children with SCA receiving CBT for abnormal transcranial Doppler (TCD) [n=12] or cerebrovascular accident (CVA) [n=22]. Baseline cerebral magnetic resonance imaging (MRI) and magnetic resonance angiogram (MRA) were compared with the most recent scans available for each patient and independently scored by a neuroradiologist. RESULTS Thirty-four patients with a mean age of 6.5years at the time of baseline MRI/MRA were studied. Average elapsed time from baseline to most recent scans was 7.3years. Overall, patients experienced worsening vasculopathy, as measured by mean increases in their baseline MRI and MRA scores of +0.76 and +1.03. There was a significant difference in the mean change of MRI/MRA scores between patients who had CVA and abnormal TCD (MRI; +1.23 vs. -0.08, p=0.001 and MRA; +1.54 vs. +0.08, p=0.02). Patients with abnormal baseline MRA had worsening scores compared to those with normal baseline MRA (54% vs. 9.5%, p=0.01). Also, patients who had CVA were more likely to have an abnormal baseline MRA and worsening scores compared to abnormal TCD patients. CONCLUSION We show that children with CVA experience progression of cerebral vasculopathy despite CBT. In contrast, CBT for abnormal TCD confers protection against the development and/or progression of cerebral vasculopathy. This effect appears to be real given our large cohort of patients with longer follow up as compared to previous studies.