Autonomic and cardiovascular dysfunction in acute cerebral ischemia: Background and study purpose

Background and study purpose: Autonomic dysfunction is a common complicatio n of cerebrovascular disease. The aim of this study was to investigate the activity of the sympathetic nervous system, and cardiovascular system in ac ute cerebral ischemia. Patients and methods: 55 patients with cerebral isch emia (onset of symptoms < 24 h prior to admission) were included into a pro spective study (mean age 61.3 +/- 1.5). Neurologic score was assessed using the Scandinavian Stroke Scale Score (SSSS). Cardiac output, mean transcran ial flow velocity in the middle cerebral artery, systolic and diastolic blo od pressure, and heart Fate were recorded. Plasma norepinephrine (NE) and e pinephrine (E) concentrations were measured with high performance liquid ch romatography (concentration in ng/l). Data was obtained during the first 5 days after stroke. Values are given as mean +/- standard error of the mean. Results: Cerebral ischemia caused an increase in sympathetic function in t he acute phase (NE: 523.1 +/- 60.0) with a significant spontaneous decrease (NE on day 5: 399.1 +/- 47.7). The alterations in autonomic function were paralleled by augmented cardiovascular parameters. Systolic and diastolic b lood pressure, and heart rate showed a significant drop. Cardiac output, on the contrary, exhibited a significant increase which was inversely correla ted to initial values. The most significant correlations existed between NE , E and systolic and diastolic blood pressure. Heart rate was predominantly modulated via the adrenergic axis. In hemispheric ischemia, mean transcran ial flow velocity was higher on the affected side. Conclusion: Our study sh ows that cerebral ischemia in the acute post-ischemic phase is accompanied by autonomic and cardiovascular dysfunction. The increase in cardiac output is possibly due to a spontaneous drop in systemic afterload. We conclude t hat plasma catecholamines are a feasible means in monitoring changes of car dio-autonomic function in acute cerebral ischemia.