Cerebral Vasoreactivity in Children with Sickle Cell Disease: A Transcranial Doppler Study

Abstract

BackgroundImpairment of vasodilatory capacity reflecting reduced cerebrovascular reserve was previously shown in adults with sickle cell disease (SCD) and might play a role in the pathophysiology of stroke in such patients. We examined the hypothesis that children with SCD would also have a higher frequency of impaired cerebral vasoreactivity when compared with healthy age- and gender-matched controls. MethodsPatients were recruited from our hematology outpatient clinic. All SCD patients aged 10-18 years without a history of symptomatic stroke as well as age- and gender-matched healthy children were evaluated with transcranial Doppler (TCD) ultrasonography, with breath-holding maneuver. Breath-holding index (BHI) was calculated by dividing the percentage increase in mean flow velocity occurring during breath holding by the length of time subjects hold their breath after a normal inspiration. BHI was considered abnormal if less than .69. ResultsTCD was performed in 42 patients (mean age 12.7 ± 2.2 years) and 20 controls (mean age 13.90 ± 3.04 years). Blood flow velocities were higher in patients with SCD than in controls in all arteries evaluated (P < .001). BHI values in patients with SCD were significantly lower than in control subjects (1.27 ± .65 versus 1.74 ± .15, P = .013 on the left and 1.16 ± .45 versus 1.61 ± .11, P = .002 on the right). BHI was abnormal in 19% of the patients and in none of the controls, P = .036. ConclusionsChildren with SCD may have impaired cerebral vasoreactivity, with low BHI values suggesting a reduced autoregulation capacity.