Relevance of Baroreflex Sensitivity in Hypertensives after Ischemic Stroke

Journal für Hypertonie - Austrian Journal of Hypertension 2012; 16 (2): 7-11

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Keywords: arterial hypertension,  Autonomic nervous system,  blood pressure,  stroke

Objective: Impaired baroreflex sensitivity (BRS) is a non-invasive marker of autonomic dysfunction which has been observed in acute stroke and is associated with a higher risk of long-term poststroke mortality and disability. The aim of the present study was to evaluate the clinical significance of baroreflex sensitivity in hypertensives ≥ 6 months after ischemic stroke onset. Design: A total of 26 hypertensive patients (66 ± 10 years of age, 11 female/15 male) with a history of the first-ever ischemic stroke, which was neuroradiologically confirmed, were studied. They were compared to 30 hypertensive patients without a history of any cardiovascular event of similar age and sex. The relationship between baroreflex sensitivity and blood pressure in hypertensives with stroke in comparison to a group of stroke-free control patients was evaluated. Method: BRS expressed in ms/mmHg or in Hz/ mmHg (BRSf) was determined by the sequence and spectral method: a 5-minute non-invasive beat-to-beat recording of blood pressure and RR interval by means of a Collin CBM-7000 monitor, controlled breathing at a frequency of 0.1 Hz. Carotid intima-media thickness (IMT) was determined using ultrasonography. Results: A significantly negative correlation between BRS and systolic blood pressure was present (p < 0.001). BRS values obtained by the spectral method (BRS spect) and sequence method (BRS seq) in hypertensives with stroke were significantly lower even ≥ 6 months after stroke onset compared to stroke-free control patients (BRS spect p = 0.0237, BRSf spect p = 0.0285, BRS seq p = 0.0532, BRSf seq = 0.0273). Significantly reduced BRS in hypertensives with stroke was associated with greater carotid IMT and bilateral carotid atherosclerosis. Conclusion: Examination of baroreflex sensitivity as a marker of autonomic dysfunction along with global cardiovascular risk stratification of post-stroke hypertensives, especially with measuring carotid intima media thickness, seems to be a method for identifying patients at high residual cardiovascular risk.