The Significance of Baroreflex Sensitivity in Hypertensive Subjects with Stroke

The relationship between baroreflex sensitivity expressed inms/mm Hg (BRS) or in Hz/mm Hg (BRSf) in hypertensives withstroke in comparison with a group of stroke-free patients wasevaluated. Twenty-six patients (aged 66±10 years, 11 females/15 males) with a history of the first ever ischemic stroke(6 months and more after stroke onset), which wasneuroradiologically confirmed, were studied. These werecompared to 30 hypertensive patients without history of anycardiovascular event, being of similar age and sex. BRS and BRSfwere determined by the sequence and spectral methods (fiveminute non-invasive beat-to-beat recording of blood pressureand inter-beat interval, controlled breathing at a frequency of0.1 Hz). A significant negative correlation between spontaneousBRS and blood pressure (BP) represented by the grade ofhypertension was present (r = -0.52, p<0.001). Differencesbetween hypertensives with and without stroke were detected inBRS obtained by the spectral method (BRS spect p=0.0237, BRSfspect p=0.0285) or BRS obtained by sequence method (BRS seqp=0.0532, BRSf seq p=0.0273). The greatest decline in BRSvalues was in hypertensive stroke patients with metabolicsyndrome, who had BRS values below 3 ms/mm Hg. We foundout that BRS and BRSf were more impaired in stroke patientswith essential hypertension even 6 months and more after strokeonset than in stroke-free hypertensive patients. This finding wasindependent of age-dependent decrease of BRS. Examination ofbaroreflex sensitivity as a marker of autonomic dysfunction alongwith global cardiovascular risk stratification of individuals seemsto be a method for identifying patients at high residualcardiovascular risk.