No increase in masked hypertension prevalence in children with sickle cell disease in France.

OBJECTIVES: An important prevalence (32-45%) of masked hypertension has been reported in children with sickle cell disease (SCD). Systemic arterial rigidity has been associated with stroke in SCD. Stroke screening is well-established using transcranial Doppler (TCD) ultrasound. The objectives of our proof-of-concept study in childhood SCD were to evaluate the prevalence of hypertension and its relationships with cerebral vasculopathy (TCD velocity) and to further evaluate in a subgroup of children the correlations of cardiovascular autonomic nervous system indices with TCD velocity.

METHODS: Ambulatory blood pressure measurement (ABPM) and TCD velocity were obtained in children with SCD and in a restricted sample, cardiac sympathovagal balance using heart rate variability analyses, baroreflex sensitivity, and pulse wave velocity were measured.

RESULTS: In 41 children with SCD (median age 14.0 years, 19 girls, SS/Sβ+thalassemia/SC: 33/2/6), ABPM results showed masked hypertension in 2/41 (5%, 95% confidence interval, 0-11) children, consistent with the prevalence in the general pediatric population, elevated BP in 4/41 (10%) children, and a lack of a normal nocturnal dip in 19/41 children (46%). Children with increased TCD velocity had lower nocturnal dipping of systolic BP. In the 10 participants with extensive cardiovascular assessment, increased TCD velocity was associated with parasympathetic withdrawal and baroreflex failure. Exaggerated orthostatic pressor response or orthostatic hypertension was observed in 7/10 children that was linked to parasympathetic withdrawal.

CONCLUSION: Autonomic nervous system dysfunction, namely loss of parasympathetic modulation, of SCD contributes to increase TCD velocity but is not associated with an increased prevalence of masked hypertension.