Transcranial doppler velocity and brain MRI/MRA changes in children with sickle cell anemia on chronic transfusions to prevent primary stroke

Abstract

Chronic transfusions help prevent primary stroke in children with sickle cell anemia (SCA) and abnormal transcranial Doppler (TCD) velocities. However, the effects of transfusions on TCD velocities and brain MRI/MRA findings are incompletely described. We reviewed TCD and brain MRI/MRA results in 27 children with SCA and abnormal TCD velocities receiving transfusions to prevent primary stroke. All TCDs were performed by a single examiner, immediately prior to a scheduled transfusion. We also examined the effects of laboratory and clinical parameters on TCD responses to transfusion therapy. For the whole cohort, the average pre-transfusion HbS on transfusions was 31.7 ± 12.3%. The most significant decline in TCD velocities occurred within 10 months of starting transfusions. Follow-up TCD values trended upward with increasing pre-transfusion %HbS levels while on treatment. Half of the children had persistent conditional/abnormal TCD velocities despite transfusions and 28% had new/progressive stenosis on MRA, but none had primary stroke during 73 patient-years of follow-up. For children with SCA and abnormal TCD velocities, transfusions lower TCD velocities and help prevent stroke, but do not always result in normal velocities or protect against progression of cerebral vasculopathy. Improved adherence to transfusion goals may improve on-treatment TCD velocities.