Beat-to-beat analysis of hemodynamic response to mental and psychological stress in sickle cell anemia.

Objectives: Vaso-occlusive crises (VOCs) are a hallmark symptom of sickle cell disease (SCD). Physical stressors can trigger decreased microvascular blood flow and increase the risk for VOCs. However, the effect of mental and psychological stressors on vascular physiology in SCD is not well-established. We hereby examined fluctuations in continuous blood pressure (BP) to evaluate hemodynamic changes in SCD patients during mental and psychological stress. Methods: Thirteen SCD (HbSS) subjects from the Children's Hospital Los Angeles and 11 healthy (HbAA) volunteers were recruited. Continuous BP was recorded as subjects participated in two mental and one psychological stress tasks. Systolic beat-to-beat BP variability (BPV) measurements were calculated for each subject. Three very short-term BPV metrics served as outcome measures: standard deviation, coefficient of variation, and average real variability. Linear mixed effects models evaluated associations between patient factors and outcome measures. Results: SCD patients were associated with increased systolic BPV and exhibited a distinct increase in BPV in response to psychological stress. All subjects exhibited a decrease in systolic BPV in response to mental stress tasks. During mental stress, both groups displayed increased augmentation index, reflective of stress-induced vasoconstriction, while psychological stress in SCD patients led to both decreased mean arterial pressure and increased AI, suggestive of uncompensated vasoconstriction. Conclusion: These findings emphasize the impact of mental and psychological stressors on vascular function in SCD, the potential for monitoring physiological signals to predict VOC events, and the importance of counseling SCD patients on lifestyle practices to reduce their stress to prevent pain.