Frequency of pain crises in sickle cell anemia and its relationship with the sympatho-vagal balance, blood viscosity and inflammation
Résumé
Background
Recent evidence suggests that autonomic nervous system activity could be involved in the
pathophysiology of sickle cell disease, but it is unclear whether differences in autonomic nervous
system activity are detectable during steady state in patients with mild and severe disease.
The aim of the present study was to compare the autonomic nervous system activity, blood
rheology, and inflammation in patients with sickle cell anemia according to the frequency of
acute pain crisis.
Design and Methods
Twenty-four healthy volunteers, 20 patients with sickle cell anemia with milder disease, and
15 patients with sickle cell anemia with more severe disease were recruited. Milder disease was
defined as having no pain crisis within the previous year. More severe disease was defined as
having had within the previous year three or more pain crises which were documented by a
physician and required treatment with narcotics. The autonomic nervous system activity was
determined by spectral analysis of nocturnal heart rate variability. Blood viscosity determination
and measurements of several inflammatory markers (interleukin-6, soluble vascular cell
adhesion molecule-1, soluble CD40 ligand and sL-selectin) were made on blood samples collected
in steady-state conditions.
Results
Results showed that: 1) patients who had suffered more frequent pain crises had lower
parasympathetic activity and greater sympatho-vagal imbalance than both controls and
patients with milder disease. However, when adjusted for age, no significant difference was
detected between the two sickle cell anemia patient groups; 2) patients who had suffered more
frequent pain crises had higher blood viscosity than patients with milder disease, and this was
not dependent on age.
Conclusions
Results from the present study indicate that both the autonomic nervous system activity and
blood viscosity are impaired in patients with sickle cell anemia exhibiting high frequency of
pain crisis in comparison with those who did not experience a crisis within the previous year.