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

Abstract

Vaso-occlusive crises are a hallmark symptom of sickle cell disease. Physical stressors can trigger decreased microvascular blood flow and increase the risk for vaso-occlusive crises. However, the effect of mental and psychological stressors on vascular physiology in sickle cell disease is not well-established. We hereby examined fluctuations in continuous blood pressure to evaluate hemodynamic changes in sickle cell disease patients during mental and psychological stress. Thirteen sickle cell disease subjects from the Children’s Hospital Los Angeles and 11 healthy volunteers were recruited. Continuous blood pressure was recorded during two mental tasks and one psychological stress task. Systolic beat-to-beat blood pressure variability measurements were calculated for each subject. Three very short-term blood pressure variability metrics served as outcome measures: standard deviation, coefficient of variation, and average real variability. Peripheral augmentation index was calculated from arterial waveforms. Linear mixed effects models evaluated associations between patient factors and outcome measures. Sickle cell disease patients exhibit increased systolic blood pressure variability in response to psychological stress. All subjects exhibited a decrease in systolic blood pressure variability in response to mental stress tasks. During mental stress, both groups displayed increased augmentation index, reflective of stress-induced vasoconstriction, while psychological stress in sickle cell disease patients led to both decreased mean arterial pressure and increased augementation index, suggestive of uncompensated vasoconstriction. These findings emphasize the impact of mental and psychological stressors on vascular function in sickle cell disease and the potential for monitoring physiological signals to predict vaso-occlusive crisis events.