Hypertension and chronic cerebrovascular disease are known to alter static cerebral autoregulation (CA) but the effects of acute stroke on dynamic CA (dCA) have not been studied in detail. Those studies date measuring dCA used sympathetically induced blood pressure (BP) changes, which may themselves directly affect dCA. This study assessed whether is compromised after using spontaneous changes as stimulus for response.56 patients with ischaemic (aged 70 (SD 9) years), within 72 hours ictus...

Background and Purpose— The baroreceptor reflex arc is important in the short-term regulation of cardiovascular system, small studies have reported impaired cardiac sensitivity (BRS) after acute stroke. However, prognostic significance BRS uncertain. Methods— One hundred twenty-four patients underwent simultaneous ECG noninvasive beat-to-beat blood pressure (BP) monitoring within 72 hours neuroradiologically confirmed ischemic Cardiac was assessed from combined α-index by means power...

The linear dynamic relationship between systemic arterial blood pressure (ABP) and cerebral flow velocity (CBFV) was studied by time- frequency-domain analysis methods. A nonlinear moving-average approach also implemented using Volterra-Wiener kernels. In 47 normal subjects, ABP measured with Finapres CBFV recorded Doppler ultrasound in both middle arteries at rest the supine position during drops induced sudden deflation of thigh cuffs. Impulse response functions estimated Fourier transfer...

Arterial pCO2 is known to influence cerebral autoregulation but its effect on the dynamic relationship between mean arterial blood pressure (ABP) and flow velocity (CBFV), obtained from spontaneous fluctuations in ABP, has not been established. In 16 normal subjects, ABP was measured non-invasively (Finapres), CBFV estimated with Doppler ultrasound middle artery, end-tidal CO2 (EtCO2) an infrared capnograph. Recordings were made before, during after breathing a mixture of 5% air. The...

Background and Purpose —Assessment of cerebral autoregulation has been traditionally performed with static changes in arterial blood pressure. Newer dynamic methods require the induction sudden drops pressure release bilateral thigh cuffs. An alternative method is proposed, based on spontaneous variability that does not its manipulation. We compared this established cuff patients carotid artery stenosis. Methods —Cerebral flow velocity (determined by transcranial Doppler) noninvasive...

It remains unclear as to whether dynamic and static cerebral autoregulation (CA) are impaired in acute ischaemic stroke, these changes related stroke subtype. This could have important implications with regard post-stroke prognosis the management of blood pressure (BP) post-ictal period. Using transcranial Doppler ultrasonography non-invasive manipulation BP, we compared both mechanisms 61 patients within 96 h ictus, 54 age- sex-matched controls. There was no difference CA indices between...

The longitudinal changes in static and dynamic cerebral autoregulation (CA) following acute ischaemic stroke are unknown were assessed this study.Fifty-four patients studied within 96 h of again 7-14 days later, using transcranial Doppler techniques to measure CA. Results compared an age-, sex- blood pressure (BP)-matched control group. Static BP pressor stimulus was produced by thigh cuff inflation rapid release.Dynamic, but not static, CA globally impaired at initial (mean index 3.9 +/-...

Background and Purpose —In hypertensive populations, increasing blood pressure (BP) levels BP variability (BPV) are associated with a greater incidence of target organ damage. After stroke, elevated 24-hour predict poor outcome, although it is uncertain whether shorter-length recordings assessing mean BPV have similar predictive role. The objectives this study were to compare the different measures beat-to-beat on outcome after acute ischemic stroke assess these parameters affected by...

Background and Purpose The blood pressure (BP) fall increased BP variability after acute stroke have been previously described. underlying pathophysiological mechanisms producing these findings are unclear but may include abnormalities of cardiac baroreceptor reflex arc and/or changes in sympathetic nervous system activity. To date, evidence impaired sensitivity (BRS) is limited to patients with chronic disease as determined by invasive methodology. Therefore, it was proposed assess BRS...

The influence of different types maneuvers that can induce sudden changes arterial blood pressure (ABP) on the cerebral flow velocity (CBFV) response was studied in 56 normal subjects (mean age 62 yr, range 23–80). ABP recorded finger with a Finapres device, and bilateral recordings CBFV were performed Doppler ultrasound middle arteries. Recordings at rest (baseline) during thigh cuff test, lower body negative pressure, cold pressor hand grip, Valsalva maneuver. From baseline recordings,...

Background and Purpose —Normal aging is associated with marked changes in the cardiovascular cerebrovascular systems. Although cerebral autoregulation (CA) impaired certain disease states, effect of age per se on dynamic CA humans unknown focus this study. Methods —Twenty-seven young subjects (≤40 years) 27 older (≥55 years), matched for sex systolic blood pressure (BP), underwent measurement flow velocity by transcranial Doppler ultrasound noninvasive beat-to-beat arterial BP during induced...

Spontaneous fluctuations in BP (blood pressure) and subsequent change CBFV (cerebral blood flow velocity) the MCA (middle cerebral artery) can be used to assess dynamic autoregulation using transfer function analysis; however, reliability of this technique has not been assessed, particular contribution intra-subject variability relative inter-subject variability. Three bilateral CBFV, RR interval recordings were performed ten healthy volunteers on four separate occasions over a 2-week...

In Brief OBJECTIVE: To test the hypothesis that preeclampsia is associated with impaired dynamic cerebral autoregulation. METHODS: a prospective cohort analysis, blood flow velocity of middle artery (determined by transcranial Doppler), pressure noninvasive arterial volume clamping), and end-tidal carbon dioxide were simultaneously collected during 7-minute period rest. The autoregulation index was calculated. Values 0 9 indicated absent perfect autoregulation, respectively. Student t used,...