scholarly journals Features of cerebral autoregulation and reactivity in patients with arterial hypertension in older age groups with orthostatic hypotensive reactions

2020 ◽  
Vol 17 (2) ◽  
pp. 48-55
Author(s):  
I. V. Atyunina ◽  
E. V. Oshchepkova ◽  
A. N. Rogoza
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Autoregulation ◽  
Age Groups ◽  
Resistance Index ◽  
Older Age ◽  
Breath Holding ◽  
Pronounced Increase ◽  
Reactivity Coefficient

Aim. To study the condition of cerebrovascular autoregulation and reactivity in different variants of orthostatic hypotensive reactions (OНR) in elderly patients with hypertension (АН). Materials and methods. 50 patients with AH were examined (80% of women) aged 60 to 82 years (68.55.3). The duration of hypertension is from 2 to 43 years (16.811.6 years).The daily blood pressure profile was evaluated by the method of daily monitoring of blood pressure (BPLab, Russia). A study of OНR was carried out using an active orthostatic test (AOP) with continuous monitoring of cerebral blood flow (CBF) and with a minute measurement of blood pressure by the oscillometric method and continuous non-invasive measurement of SBP (systolic blood pressure) and DBP (diastolic blood pressure) in the finger artery (Task Force Monitor CNSystems Austria). The CBF velocity in the middle cerebral artery (SMA) was estimated using a transcranial sensor with a frequency of 2 MHz on an Angiodin-2K ultrasound machine (BIOSS company, Russia). In SMA, systolic (Vs), diastolic (Vd), average cerebral blood flow velocity ACBF (Vm), pulsation index (Pi), and vascular resistance index (Ri) were recorded. The difference between the indicators was calculated initially and during AOP (in the first 30 seconds and for 3 minutes): Vm30s, %, Vm3m, %. Reactivity was assessed using a hypercapnic test (HCP) with breath holding. The relative change in the CBF indicators in the MCA was calculated by the formula: Kr = (Vm1Vm2)100%/Vm1, where Kr is the reactivity coefficient, Vm1 ACBF at rest; Vm2 ACBF during the test. Statistical analysis was performed using the non-parametric MannWhitney method using Statistica 6.0. Results. In 17 (34%) patients with AH, OGR was detected. In 6 (12%) examined patients, initial OHR (IOH) was detected, in 6 (12%) classic OHR (COH), in 5 (10%) there was a combination of COH+IOH. According to the ABPM data, in patients with OHR compared with patients without OHR, there were no significant differences in the daily level of blood pressure (mmHg), SBP: 131.712.2 vs 131.313.8, p0.05; DBP 74.311.8 vs 75.38.9, p0.05). In AOP, patients with OHR significantly decreased Vm in orthostasis compared with patients without OHR, both in the first30 seconds and at 3 minutes (Vm30s: 25.05.5 vs 30.44.7, p0.05; Vm3m: 27.05.2 vs 31.24.7, p0.05; Vm30s,%: 17.06.5 vs 8.34, 1, p0.05; Vm3m,%: 11.76.3 vs 5.82.4, p0.05). When performing HCТ between patients with OHR and without OHR, statistically significant differences in the indices Pi (0.790.08 vs 0.780.16, p0.05) and Ri (0.510.09 vs 0.530.07, p0.05) was not detected, however, in patients with OHR there is a tendency to a less pronounced increase in АCBF at the peak of HCT compared with patients without OHR (36.86.4 vs 40, 06.6, p=0.13). In patients with OHR, the cerebral reactivity coefficient was lower than in patients without OHR (13.43.9 vs 20.76.6, p0.05). Conclusions. In patients with AH of older age groups with OHR, a statistically significant decrease in ACBF in orthostasis was revealed. Patients with IOH showed a decrease in ACBF in the first seconds of orthostasis with its subsequent stabilization. Persons with COH have preserved the mechanisms of cerebral autoregulation in the first seconds of orthostasis, but with prolonged orthostatic load (3 minutes), the effectiveness of autoregulatory mechanisms decreases. OHR in patients with hypertension of older age groups is associated with a decrease in cerebral reactivity.

Cerebral hemodynamics in patients with arterial hypertension of the older age groups with orthostatic hypotensive reactions

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
I Atyunina ◽  
E Oschepkova ◽  
A Rogoza ◽  
N Lazareva
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Arterial Hypertension ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Age Groups ◽  
Cerebral Hemodynamics ◽  
Older Age

Abstract Objective To study cerebrovascular autoregulation in pts with arterial hypertension (AH) with orthostatic hypotensive reactions (OHR) during an active orthostatic test (AOT). 50 pts with AH (40 g, 10 m), 68.5±5.3 years, I-III gr. were examined. Blood pressure monitoring (BPM) by “BP Lab”, Russia. AOT was performed with continuous measurement of systolic blood pressure (SBP) and diastolic blood pressure (DBP) in the digital artery (“Task Force Monitor”, “CNSystems” Austria). The criteria for the OHR were evaluated according to guidelines ESC, 2018. Cerebral hemodynamics in the middle cerebral artery (MCA) was monitored during the AOT (Angiodin-2K (BIOSS company, Russia), using a transcranial sensor with a freq. of 2 MHz. In the MCA, systolic (Vs), diastolic (Vd), average cerebral blood flow velocity (Vm), pulsation index (Pi), and vascular resistance index (Ri), the difference ΔVm30s,% and ΔVm30s, were recorded. Statistical analysis was performed using the non-parametric Mann-Whitney method using Statistica 6.0 Results In 17 (34%) pts with AH, OHR was detected. BP in pts with OHR compared with pts without OHR (mmHg), SBP: 131.7±12.2 vs 131.3±13.8, p>0.05; DBP 74.3±11.8 vs 75.3±8.9, p>0.05). In AOT in pts with OHR, the Vm in the orthostasis significantly decreased compared to pts without OHR, both in the first 30 s. and at 3 min. (Tabl.1). Conclusions In pts with AH of older age groups with OHR, in comparison with the same category of pts without OHR, there is a change in cerebral autoregulation in the form of a more pronounced decrease in cerebral blood flow velocity in MCA in the orthostatic position. Funding Acknowledgement Type of funding source: None

scholarly journals Impaired dynamic cerebral autoregulation in trained breath-hold divers

2019 ◽  
Vol 126 (6) ◽  
pp. 1694-1700 ◽  
Author(s):  
M. Erin Moir ◽  
Stephen A. Klassen ◽  
Baraa K. Al-Khazraji ◽  
Emilie Woehrle ◽  
Sydney O. Smith ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Autoregulation ◽  
Cerebral Blood Flow Velocity ◽  
Carbon Dioxide Partial Pressure ◽  
Breath Hold ◽  
Dynamic Cerebral Autoregulation

Breath-hold divers (BHD) experience repeated bouts of severe hypoxia and hypercapnia with large increases in blood pressure. However, the impact of long-term breath-hold diving on cerebrovascular control remains poorly understood. The ability of cerebral blood vessels to respond rapidly to changes in blood pressure represents the property of dynamic autoregulation. The current investigation tested the hypothesis that breath-hold diving impairs dynamic autoregulation to a transient hypotensive stimulus. Seventeen BHD (3 women, 11 ± 9 yr of diving) and 15 healthy controls (2 women) completed two or three repeated sit-to-stand trials during spontaneous breathing and poikilocapnic conditions. Heart rate (HR), finger arterial blood pressure (BP), and cerebral blood flow velocity (BFV) from the right middle cerebral artery were measured continuously with three-lead electrocardiography, finger photoplethysmography, and transcranial Doppler ultrasonography, respectively. End-tidal carbon dioxide partial pressure was measured with a gas analyzer. Offline, an index of cerebrovascular resistance (CVRi) was calculated as the quotient of mean BP and BFV. The rate of the drop in CVRi relative to the change in BP provided the rate of regulation [RoR; (∆CVRi/∆T)/∆BP]. The BHD demonstrated slower RoR than controls ( P ≤ 0.001, d = 1.4). Underlying the reduced RoR in BHD was a longer time to reach nadir CVRi compared with controls ( P = 0.004, d = 1.1). In concert with the longer CVRi response, the time to reach peak BFV following standing was longer in BHD than controls ( P = 0.01, d = 0.9). The data suggest impaired dynamic autoregulatory mechanisms to hypotension in BHD. NEW & NOTEWORTHY Impairments in dynamic cerebral autoregulation to hypotension are associated with breath-hold diving. Although weakened autoregulation was observed acutely in this group during apneic stress, we are the first to report on chronic adaptations in cerebral autoregulation. Impaired vasomotor responses underlie the reduced rate of regulation, wherein breath-hold divers demonstrate a prolonged dilatory response to transient hypotension. The slower cerebral vasodilation produces a longer perturbation in cerebral blood flow velocity, increasing the risk of cerebral ischemia.

Fundamental relationships between arterial baroreflex sensitivity and dynamic cerebral autoregulation in humans

2010 ◽  
Vol 108 (5) ◽  
pp. 1162-1168 ◽  
Author(s):  
Yu-Chieh Tzeng ◽  
Samuel J. E. Lucas ◽  
Greg Atkinson ◽  
Chris K. Willie ◽  
Philip N. Ainslie
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transfer Function ◽  
Blood Flow Velocity ◽  
Cerebral Autoregulation ◽  
Baroreflex Sensitivity ◽  
Cerebral Blood Flow Velocity ◽  
Arterial Baroreflex ◽  
Dynamic Cerebral Autoregulation

The functional relationship between dynamic cerebral autoregulation (CA) and arterial baroreflex sensitivity (BRS) in humans is unknown. Given that adequate cerebral perfusion during normal physiological challenges requires the integrated control of CA and the arterial baroreflex, we hypothesized that between-individual variability in dynamic CA would be related to BRS in humans. We measured R-R interval, blood pressure, and cerebral blood flow velocity (transcranial Doppler) in 19 volunteers. BRS was estimated with the modified Oxford method (nitroprusside-phenylephrine injections) and spontaneous low-frequency (0.04–0.15) α-index. Dynamic CA was quantified using the rate of regulation (RoR) and autoregulatory index (ARI) derived from the thigh-cuff release technique and transfer function analysis of spontaneous oscillations in blood pressure and mean cerebral blood flow velocity. Results show that RoR and ARI were inversely related to nitroprusside BRS [ R = −0.72, confidence interval (CI) −0.89 to −0.40, P = 0.0005 vs. RoR; R = −0.69, CI −0.88 to −0.35, P = 0.001 vs. ARI], phenylephrine BRS ( R = −0.66, CI −0.86 to −0.29, P = 0.0002 vs. RoR; R = −0.71, CI −0.89 to −0.38, P = 0.0001 vs. ARI), and α-index ( R = −0.70, CI −0.89 to −0.40, P = 0.0008 vs. RoR; R = −0.62, CI −0.84 to −0.24, P = 0.005 vs. ARI). Transfer function gain was positively related to nitroprusside BRS ( R = 0.62, CI 0.24–0.84, P = 0.0042), phenylephrine BRS ( R = 0.52, CI 0.10–0.79, P = 0.021), and α-index ( R = 0.69, CI 0.35–0.88, P = 0.001). These findings indicate that individuals with an attenuated dynamic CA have greater BRS (and vice versa), suggesting the presence of possible compensatory interactions between blood pressure and mechanisms of cerebral blood flow control in humans. Such compensatory adjustments may account for the divergent changes in dynamic CA and BRS seen, for example, in chronic hypotension and spontaneous hypertension.

scholarly journals Blood flow response to orthostatic challenge identifies signatures of the failure of static cerebral autoregulation in patients with cerebrovascular disease

BMC Neurology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Clara Gregori-Pla ◽  
Rickson C. Mesquita ◽  
Christopher G. Favilla ◽  
David R. Busch ◽  
Igor Blanco ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Cerebral Autoregulation ◽  
Cerebrovascular Disorders ◽  
Blood Flow Response ◽  
Flow Response ◽  
Ica Stenosis

Abstract Background The cortical microvascular cerebral blood flow response (CBF) to different changes in head-of-bed (HOB) position has been shown to be altered in acute ischemic stroke (AIS) by diffuse correlation spectroscopy (DCS) technique. However, the relationship between these relative ΔCBF changes and associated systemic blood pressure changes has not been studied, even though blood pressure is a major driver of cerebral blood flow. Methods Transcranial DCS data from four studies measuring bilateral frontal microvascular cerebral blood flow in healthy controls (n = 15), patients with asymptomatic severe internal carotid artery stenosis (ICA, n = 27), and patients with acute ischemic stroke (AIS, n = 72) were aggregated. DCS-measured CBF was measured in response to a short head-of-bed (HOB) position manipulation protocol (supine/elevated/supine, 5 min at each position). In a sub-group (AIS, n = 26; ICA, n = 14; control, n = 15), mean arterial pressure (MAP) was measured dynamically during the protocol. Results After elevated positioning, DCS CBF returned to baseline supine values in controls (p = 0.890) but not in patients with AIS (9.6% [6.0,13.3], mean 95% CI, p < 0.001) or ICA stenosis (8.6% [3.1,14.0], p = 0.003)). MAP in AIS patients did not return to baseline values (2.6 mmHg [0.5, 4.7], p = 0.018), but in ICA stenosis patients and controls did. Instead ipsilesional but not contralesional CBF was correlated with MAP (AIS 6.0%/mmHg [− 2.4,14.3], p = 0.038; ICA stenosis 11.0%/mmHg [2.4,19.5], p < 0.001). Conclusions The observed associations between ipsilateral CBF and MAP suggest that short HOB position changes may elicit deficits in cerebral autoregulation in cerebrovascular disorders. Additional research is required to further characterize this phenomenon.

Transfer function analysis for the assessment of cerebral autoregulation using spontaneous oscillations in blood pressure and cerebral blood flow

2014 ◽  
Vol 36 (5) ◽  
pp. 563-575 ◽  
Author(s):  
Aisha S.S. Meel-van den Abeelen ◽  
Arenda H.E.A. van Beek ◽  
Cornelis H. Slump ◽  
Ronney B. Panerai ◽  
Jurgen A.H.R. Claassen
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transfer Function ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Transfer Function Analysis ◽  
Spontaneous Oscillations

Brain adenosine production in rat during sustained alteration in systemic blood pressure

1980 ◽  
Vol 239 (5) ◽  
pp. H636-H641 ◽  
Author(s):  
H. R. Winn ◽  
J. E. Welsh ◽  
R. Rubio ◽  
R. M. Berne
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Autoregulation ◽  
Adenine Nucleotides ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Arterial Blood ◽  
Adenosine Concentration ◽  
Severe Hypotension

Brain production of adenosine and its metabolites, inosine and hypoxanthine was determined in 46 rats during sustained (5 min) reduction in mean arterial blood pressure (MABP) caused by hemorrhage. Also measured were ATP, ADP, AMP, phosphocreatine (PCr), and lactate. Brain tissue was obtained by the freeze-blowing technique. Ventilation was controlled to maintain constant arterial O2 tension, CO2 tension, and pH. When MABP was decreased from 135 + 3 (SE) mmHg to 72 +/- 2 mmHg, within the range of cerebral autoregulation, brain adenosine concentration doubled from 0.55 +/- 0.12 to 1.16 +/- 0.13 nmol/g (P < 0.015). Unlike the changes in adenosine concentrations, adenine nucleotides and PCr remained stable. Lactate varied inversely with MABP. With moderate to severe hypotension (MABP = 45 +/- 3 mmHg), adenosine levels increased almost sixfold. The increment in brain adenosine concentration within the autoregulatory range supports a role for this potent dilator of pial vessels in the regulation of cerebral blood flow.

scholarly journals Dynamic cerebral autoregulation estimates derived from near infrared spectroscopy and transcranial Doppler are similar after correction for transit time and blood flow and blood volume oscillations

2018 ◽  
Vol 40 (1) ◽  
pp. 135-149 ◽  
Author(s):  
Jan Willem J Elting ◽  
Jeanette Tas ◽  
Marcel JH Aries ◽  
Marek Czosnyka ◽  
Natasha M Maurits
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transit Time ◽  
Phase Difference ◽  
Cerebral Autoregulation ◽  
Cerebral Blood Flow Velocity ◽  
Intraclass Correlation ◽  
Arterial Blood ◽  
Dynamic Cerebral Autoregulation

We analysed mean arterial blood pressure, cerebral blood flow velocity, oxygenated haemoglobin and deoxygenated haemoglobin signals to estimate dynamic cerebral autoregulation. We compared macrovascular (mean arterial blood pressure-cerebral blood flow velocity) and microvascular (oxygenated haemoglobin-deoxygenated haemoglobin) dynamic cerebral autoregulation estimates during three different conditions: rest, mild hypocapnia and hypercapnia. Microvascular dynamic cerebral autoregulation estimates were created by introducing the constant time lag plus constant phase shift model, which enables correction for transit time, blood flow and blood volume oscillations (TT-BF/BV correction). After TT-BF/BV correction, a significant agreement between mean arterial blood pressure-cerebral blood flow velocity and oxygenated haemoglobin-deoxygenated haemoglobin phase differences in the low frequency band was found during rest (left: intraclass correlation=0.6, median phase difference 29.5° vs. 30.7°, right: intraclass correlation=0.56, median phase difference 32.6° vs. 39.8°) and mild hypocapnia (left: intraclass correlation=0.73, median phase difference 48.6° vs. 43.3°, right: intraclass correlation=0.70, median phase difference 52.1° vs. 61.8°). During hypercapnia, the mean transit time decreased and blood volume oscillations became much more prominent, except for very low frequencies. The transit time related to blood flow oscillations was remarkably stable during all conditions. We conclude that non-invasive microvascular dynamic cerebral autoregulation estimates are similar to macrovascular dynamic cerebral autoregulation estimates, after TT-BF/BV correction is applied. These findings may increase the feasibility of non-invasive continuous autoregulation monitoring and guided therapy in clinical situations.

Cerebral autoregulation in migraine with aura: A case control study

Cephalalgia ◽  
2018 ◽  
Vol 39 (5) ◽  
pp. 635-640 ◽  
Author(s):  
Cédric Gollion ◽  
Nathalie Nasr ◽  
Nelly Fabre ◽  
Michèle Barège ◽  
Marc Kermorgant ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Transfer Function ◽  
Arterial Blood Pressure ◽  
Migraine With Aura ◽  
Cerebral Autoregulation ◽  
Arterial Blood ◽  
Transfer Function Analysis ◽  
History Of

Background Migraine with aura is independently associated with increased risk of ischemic stroke, especially in younger subjects. This association might be related to an impairment of cerebral autoregulation, which normally maintains cerebral blood flow independent of arterial blood pressure variations. Methods Patients aged 30–55, fulfilling ICHD-3 beta criteria for migraine with aura, were prospectively enrolled and compared with gender- and age-matched healthy controls without a history of migraine. Patients and controls with a history of stroke or any disease potentially impairing cerebral autoregulation were excluded. We assessed cerebral autoregulation with two different methods: Transfer function analysis, and the correlation coefficient index Mx. The transfer function phase and gain reflect responses of cerebral blood flow velocities to relatively fast fluctuations of arterial blood pressure, whereas Mx also reflects responses to slower arterial blood pressure fluctuations. Results A total of 22 migraine with aura patients (median age [IQR]: 39.5 [12.5] years) and 22 controls (39 [9.75] years) were included. Transfer function parameters and Mx were not different between patients and controls. However, Mx was inversely correlated with age in patients (ρ = −0.567, p = 0.006) and not in controls (ρ = −0.084, p = 0.509). Mx was also inversely correlated with migraine with aura duration (ρ = −0.617, p = 0.002), suggesting improvement of cerebral autoregulation efficiency with disease duration. Conclusions Cerebral autoregulation did not differ between patients and controls aged 30–55. However, cerebral autoregulation efficiency was strongly correlated with migraine with aura duration. Further studies in younger patients are needed to determine whether cerebral autoregulation is impaired early in the course of disease. Trial Registration NCT02708797.

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