Cardiovascular Autonomic and Hormonal Dysregulation in Ischemic Stroke with an Emphasis on Survival

Ischemic stroke is associated with cardiovascular autonomic nervous system (ANS) disturbances, including reduced heart rate (HR) variability and acute phase neurohumoral activation with elevated stress hormone levels. The impact of HR variability and neurohumoral factors such as natriuretic peptides on the long-term survival of patients with ischemic stroke has not been studied previously. This study was designed to evaluate cardiovascular autonomic regulation in ischemic stroke patients by assessing HR dynamics and various neurohumoral factors. The values of the assessed variables in predicting mortality were evaluated. HR variability assessments were performed in the acute phase of ischemic stroke and for a general elderly population. Various neurohumoral factors were also assessed in the acute phase of stroke. After follow-up, the survival of the subjects was assessed and the prognostic values of the measured factors were evaluated. Stroke patients were found to have cardiovascular autonomic and hormonal disturbances manifested as reduced traditional time and frequency domain measures of HR variability, altered long-term HR dynamics and elevated levels of natriuretic peptides in the acute phase. Altered longterm HR dynamics in the acute phase of stroke predicted long-term mortality after stroke and cerebrovascular mortality in the general elderly population. Neuroendocrine activation involving elevated natriuretic peptide values that were associated with high cortisol and catecholamine levels was observed in the acute phase of ischemic stroke. Neurohumoral disturbance was prognostically unfavourable. The most powerful predictors of poststroke mortality were altered long-term HR dynamics and elevated levels of natriuretic peptides and cortisol, which predicted mortality independently of the conventional risk factors in multivariate analysis. Prognostically unfavourable cardiovascular autonomic dysfunction with disturbances in the longterm behaviour of HR dynamics was found to be related to ischemic stroke. Neurohormonal activation with elevated natriuretic peptide and cortisol levels in the acute phase predicts long-term mortality after ischemic stroke.