Cardiac baroreflex function and dynamic cerebral autoregulation in elderly Masters athletes

2013 ◽  
Vol 114 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Vincent L. Aengevaeren ◽  
Jurgen A. H. R. Claassen ◽  
Benjamin D. Levine ◽  
Rong Zhang
Keyword(s):  
Older Adults ◽  
Exercise Training ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Baroreflex Function ◽  
Transfer Function Analysis ◽  
Masters Athletes ◽  
The Impact ◽  
Dynamic Cerebral Autoregulation ◽  
Lifelong Exercise

Cerebral blood flow (CBF) is stably maintained through the combined effects of blood pressure (BP) regulation and cerebral autoregulation. Previous studies suggest that aerobic exercise training improves cardiac baroreflex function and beneficially affects BP regulation, but may negatively affect cerebral autoregulation. The purpose of this study was to reveal the impact of lifelong exercise on cardiac baroreflex function and dynamic cerebral autoregulation (CA) in older adults. Eleven Masters athletes (MA) (8 men, 3 women; mean age 73 ± 6 yr; aerobic training >15 yr) and 12 healthy sedentary elderly (SE) (7 men, 5 women; mean age 71 ± 6 yr) participated in this study. BP, CBF velocity (CBFV), and heart rate were measured during resting conditions and repeated sit-stand maneuvers to enhance BP variability. Baroreflex gain was assessed using transfer function analysis of spontaneous changes in systolic BP and R-R interval in the low frequency range (0.05–0.15 Hz). Dynamic CA was assessed during sit-stand–induced changes in mean BP and CBFV at 0.05 Hz (10 s sit, 10 s stand). Cardiac baroreflex gain was more than doubled in MA compared with SE (MA, 7.69 ± 7.95; SE, 3.18 ± 1.29 ms/mmHg; P = 0.018). However, dynamic CA was similar in the two groups (normalized gain: MA, 1.50 ± 0.56; SE, 1.56 ± 0.42% CBFV/mmHg; P = 0.792). These findings suggest that lifelong exercise improves cardiac baroreflex function, but does not alter dynamic CA. Thus, beneficial effects of exercise training on BP regulation can be achieved in older adults without compromising dynamic regulation of CBF.

The Interaction of Dynamic Cerebral Autoregulation and Neurovascular Coupling in Cognitive Impairment

2021 ◽  
Vol 18 (14) ◽  
pp. 1067-1076
Author(s):  
Lucy C. Beishon ◽  
Kannakorn Intharakham ◽  
Victoria J. Haunton ◽  
Thompson G. Robinson ◽  
Ronney B. Panerai
Keyword(s):  
Older Adults ◽  
Cognitive Impairment ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Neurovascular Coupling ◽  
Cognitively Impaired ◽  
Healthy Older Adults ◽  
Transfer Function Analysis ◽  
Dynamic Cerebral Autoregulation ◽  
Task Activation

Background: Dynamic cerebral autoregulation (dCA) remains intact in both ageing and dementia, but studies of neurovascular coupling (NVC) have produced mixed findings. Objective: We investigated the effects of task-activation on dCA in healthy older adults (HOA), and patients with mild cognitive impairment (MCI) and Alzheimer’s Disease (AD). Methods: Resting and task-activated data from thirty HOA, twenty-two MCI, and thirty-four AD were extracted from a database. The autoregulation index (ARI) was determined at rest and during five cognitive tasks from transfer function analysis. NVC responses were present where group-specific thresholds of cross-correlation peak function and variance ratio were exceeded. Cumulative response rate (CRR) was the total number of positive responses across five tasks and two hemispheres. Results: ARI differed between groups in dominant (p=0.012) and non-dominant (p=0.042) hemispheres at rest but not during task-activation (p=0.33). ARI decreased during language and memory tasks in HOA (p=0.002) but not in MCI or AD (p=0.40). There was a significant positive correlation between baseline ARI and CRR in all groups (r=0.26, p=0.018), but not within sub-groups. Conclusion: dCA efficiency was reduced in task-activation in healthy but not cognitively impaired participants. These results indicate differences in neurovascular processing in healthy older adults relative to cognitively impaired individuals.

scholarly journals Lifelong Exercise Improves Cardiac Baroreflex Function But Not Dynamic Cerebral Autoregulation In Older Adults

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Vincent Laurens Aengevaeren ◽  
Kyle Armstrong ◽  
Dean Palmer ◽  
Benjamin Levine ◽  
Rong Zhang
Keyword(s):  
Older Adults ◽  
Cerebral Autoregulation ◽  
Baroreflex Function ◽  
Dynamic Cerebral Autoregulation ◽  
Lifelong Exercise

scholarly journals Dynamic Cerebral Autoregulation Post Endovascular Thrombectomy in Acute Ischemic Stroke

2020 ◽  
Vol 10 (9) ◽  
pp. 641
Author(s):  
Faheem Sheriff ◽  
Pedro Castro ◽  
Mariel Kozberg ◽  
Sarah LaRose ◽  
Andrew Monk ◽  
...  
Keyword(s):  
Cerebral Artery ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Blood Pressure Monitoring ◽  
Multiple Time ◽  
Monitoring And Control ◽  
Endovascular Thrombectomy ◽  
Transfer Function Analysis ◽  
The Impact ◽  
Dynamic Cerebral Autoregulation

The development of the endovascular thrombectomy (EVT) technique has revolutionized acute stroke management for patients with large vessel occlusions (LVOs). The impact of successful recanalization using an EVT on autoregulatory profiles is unknown. A more complete understanding of cerebral autoregulation in the context of EVT may assist with post-procedure hemodynamic optimization to prevent complications. We examined cerebral autoregulation in 107 patients with an LVO in the anterior circulation (proximal middle cerebral artery (M1/2) and internal cerebral artery (ICA) terminus) who had been treated using an EVT. Dynamic cerebral autoregulation was assessed at multiple time points, ranging from less than 24 hours to 5 days following last seen well (LSW) time, using transcranial Doppler ultrasound recordings and transfer function analysis. Complete (Thrombolysis in Cerebral Infarction (TICI) 3) recanalization was associated with a more favorable autoregulation profile compared with TICI 2b or poorer recanalization (p < 0.05), which is an effect that was present after accounting for differences in the infarct volumes. Less effective autoregulation in the first 24 h following the LSW time was associated with increased rates of parenchymal hematoma types 1 and 2 hemorrhagic transformations (PH1–PH2). These data suggest that patients with incomplete recanalization and poor autoregulation (especially within the first 24 h post-LSW time) may warrant closer blood pressure monitoring and control in the first few days post ictus.

Midlife Aerobic Exercise and Dynamic Cerebral Autoregulation: Associations with Baroreflex Sensitivity and Central Arterial Stiffness

2021 ◽  
Author(s):  
Tsubasa Tomoto ◽  
Justin Repshas ◽  
Rong Zhang ◽  
Takashi Tarumi
Keyword(s):  
Arterial Stiffness ◽  
Aerobic Exercise ◽  
Cerebral Autoregulation ◽  
Baroreflex Sensitivity ◽  
Function Analysis ◽  
Middle Aged ◽  
Age Related ◽  
Transfer Function Analysis ◽  
Carotid Distensibility ◽  
Dynamic Cerebral Autoregulation

Midlife aerobic exercise may significantly impact age-related changes in the cerebro- and cardiovascular regulations. This study investigated the associations of midlife aerobic exercise with dynamic cerebral autoregulation (dCA), cardiovagal baroreflex sensitivity (BRS), and central arterial stiffness. Twenty middle-aged athletes (MA) who had aerobic training for >10 years were compared with 20 young (YS) and 20 middle-aged sedentary (MS) adults. Beat-to-beat cerebral blood flow velocity, blood pressure (BP), and heart rate were measured at rest and during forced BP oscillations induced by repeated sit-stand maneuvers at 0.05 Hz. Transfer function analysis was used to calculate dCA and BRS parameters. Carotid distensibility was measured by ultrasonography. MA had the highest peak oxygen uptake (VO2peak) among all groups. During forced BP oscillations, MS showed lower BRS gain than YS, but this age-related reduction was absent in MA. Conversely, dCA was similar among all groups. At rest, BRS and dCA gains at low frequency (~0.1 Hz) were higher in the MA compared with MS and YS groups. Carotid distensibility was similar between MA and YS groups, but it was lower in the MS. Across all subjects, VO2peak was positively associated with BRS gains at rest and during forced BP oscillations (r=0.257~0.382, p=0.003~0.050) and carotid distensibility (r=0.428~0.490, p=0.001). Furthermore, dCA gain at rest and carotid distensibility were positively correlated with BRS gain at rest in YS and MA groups (all p<0.05). These findings suggest that midlife aerobic exercise improves central arterial elasticity and BRS which may contribute to CBF regulation through dCA.

Prenatal exercise and cardiovascular health (PEACH) study: impact of acute and chronic exercise on cerebrovascular hemodynamics and dynamic cerebral autoregulation

2021 ◽  
Author(s):  
Rachel J. Skow ◽  
Lawrence Labrecque ◽  
Jade A. Rosenberger ◽  
Patrice Brassard ◽  
Craig D. Steinback ◽  
...  
Keyword(s):  
Exercise Training ◽  
Gestational Age ◽  
Cerebral Autoregulation ◽  
Acute Exercise ◽  
Controlled Trial ◽  
Moderate Intensity ◽  
Chronic Exercise ◽  
Arterial Blood ◽  
The Impact ◽  
Dynamic Cerebral Autoregulation

We performed a randomised controlled trial measuring dynamic cerebral autoregulation (dCA) using a sit-to-stand maneuver before (SS1) and following (SS2) an acute exercise test at 16-20 weeks gestation (trimester 2; TM2) and then again at 34-37 weeks gestation (third trimester; TM3). Following the first assessment, women were randomised into exercise training or control (standard care) groups; women in the exercise training group were prescribed moderate intensity aerobic exercise for 25-40 minutes on 3-4 days per week for 14±1weeks. Resting seated mean blood velocity in the middle cerebral artery (MCAvmean) was lower in TM3 compared to TM2 but not impacted by exercise training intervention. dCA was not impacted by gestational age, or exercise training during SS1. During SS2, dCA was altered such that there were greater absolute and relative decreases in mean arterial blood pressure (MAP) and MCAvmean, but this was not impacted by the intervention. There was also no difference in the relationship between the decrease in MCAvmean compared to the decrease in MAP (%/%), or the onset of the regulatory response with respect to acute exercise, gestational age, or intervention; however, rate of regulation was faster in women in the exercise group following acute exercise (interaction effect, p=0.048). These data highlight the resilience of the cerebral circulation in that dCA was well maintained or improved in healthy pregnant women between TM2 and TM3. However, future work addressing the impact of acute and chronic exercise on dCA in women who are at risk for cardiovascular complications during pregnancy is needed.

scholarly journals Assessment of cerebral autoregulation in stroke: A systematic review and meta-analysis of studies at rest

2019 ◽  
Vol 39 (11) ◽  
pp. 2105-2116 ◽  
Author(s):  
Kannakorn Intharakham ◽  
Lucy Beishon ◽  
Ronney B Panerai ◽  
Victoria J Haunton ◽  
Thompson G Robinson
Keyword(s):  
Systematic Review ◽  
Cerebral Autoregulation ◽  
Hemorrhagic Stroke ◽  
Function Analysis ◽  
Meta Analysis ◽  
Cerebrovascular Diseases ◽  
Transfer Function Analysis ◽  
Autoregulation Index ◽  
Meta Analyses ◽  
Dynamic Cerebral Autoregulation

Dynamic cerebral autoregulation (dCA) has been shown to be impaired in cerebrovascular diseases, but there is a lack of consistency across different studies and the different metrics that have been proposed for assessment. We performed a systematic review and meta-analyses involving assessment of dCA in ischemic and hemorrhagic stroke. Thirty-three articles describing assessment of dCA with transfer function analysis (TFA) were included, with meta-analyses performed for derived parameters of gain, phase and autoregulation index (ARI). A total of 1233 patients were pooled from 12 studies on acute ischemic stroke (AIS) and two studies on intracerebral hemorrhage (ICH). In comparison with controls, TFA phase of AIS was significantly reduced (nine studies), in both hemispheres ( P < 0.0001). TFA gain provided inconsistent results, with reduced values in relation to controls, for both hemispheres. The ARI (six studies) was reduced compared to controls, in both hemispheres ( P < 0.005). In ICH, gain showed higher values compared to controls for the unaffected ( P = 0.01), but not for the affected hemisphere. Meta-analyses in AIS have demonstrated that phase and the ARI index can show highly significant differences in comparison with healthy controls, while ICH have been limited by the scarcity of studies and the diversity of units adopted for gain.

scholarly journals N‐Terminal Pro Brain, N‐Terminal Pro Atrial Natriuretic Peptides, and Dynamic Cerebral Autoregulation

2020 ◽  
Vol 9 (20) ◽  
Author(s):  
Simin Mahinrad ◽  
Behnam Sabayan ◽  
Chaney R. Garner ◽  
Donald M. Lloyd‐Jones ◽  
Farzaneh A. Sorond
Keyword(s):  
Natriuretic Peptides ◽  
Cerebral Autoregulation ◽  
Small Vessel Disease ◽  
Function Analysis ◽  
Transcranial Doppler Ultrasound ◽  
Linear Regression Models ◽  
Lower Phase ◽  
Cerebrovascular Function ◽  
Transfer Function Analysis ◽  
Dynamic Cerebral Autoregulation

Background Elevated natriuretic peptides (NP) are associated with adverse cerebrovascular conditions including stroke, cerebral small vessel disease, and dementia. However, the mechanisms underlying these associations remain unclear. In this study, we examined the relationship of NT‐proBNP (N‐terminal pro brain NP) and NT‐proANP (N‐terminal pro atrial NP) with cerebrovascular function, measured by cerebral autoregulation. Methods and Results We included 154 participants (mean age 56±4 years old) from the CARDIA (Coronary Artery Risk Development in Young Adults) cohort. NT‐proBNP and NT‐proANP were measured in blood samples from the year 25 examination using electrochemiluminescence Immunoassay and enzyme‐linked immunoassay, respectively. Dynamic cerebral autoregulation (dCA) was assessed at the year 30 examination by transcranial Doppler ultrasound, using transfer function analysis (phase and gain) of spontaneous blood pressure and flow velocity oscillations, where lower phase and higher gain reflect less efficient cerebral autoregulation. We used multivariable linear regression models adjusted for demographics, vascular risk factors, and history of kidney and cardiac diseases. Higher NT‐proBNP levels at year 25 were associated with lower phase (β [95% CI]=−5.30 lower degrees of phase [−10.05 to −0.54]) and higher gain (β [95% CI]=0.06 higher cm/s per mm Hg of gain [0.004–0.12]) at year 30. Similarly, higher NT‐proANP levels were associated with lower phase (β [95% CI]=−9.08 lower degrees of phase [−16.46 to −1.70]). Conclusions Higher circulating levels of NT‐proBNP and NT‐proANP are associated with less efficient dCA 5 years later. These findings link circulating NP to cerebral autoregulation and may be one mechanism tying NP to adverse cerebrovascular outcomes.

Dynamic cerebral autoregulation during brain activation paradigms

2005 ◽  
Vol 289 (3) ◽  
pp. H1202-H1208 ◽  
Author(s):  
Ronney B. Panerai ◽  
Michelle Moody ◽  
Penelope J. Eames ◽  
John F. Potter
Keyword(s):  
Transfer Function ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Brain Activation ◽  
Hemispheric Lateralization ◽  
Step Response ◽  
Arterial Blood ◽  
Transfer Function Analysis ◽  
The Right ◽  
Dynamic Cerebral Autoregulation

Dynamic cerebral autoregulation (CA) describes the transient response of cerebral blood flow (CBF) to rapid changes in arterial blood pressure (ABP). We tested the hypothesis that the efficiency of dynamic CA is increased by brain activation paradigms designed to induce hemispheric lateralization. CBF velocity [CBFV; bilateral, middle cerebral artery (MCA)], ABP, ECG, and end-tidal Pco2 were continuously recorded in 14 right-handed healthy subjects (21–43 yr of age), in the seated position, at rest and during 10 repeated presentations (30 s on-off) of a word generation test and a constructional puzzle. Nonstationarities were not found during rest or activation. Transfer function analysis of the ABP-CBFV (i.e., input-output) relation was performed for the 10 separate 51.2-s segments of data during activation and compared with baseline data. During activation, the coherence function below 0.05 Hz was significantly increased for the right MCA recordings for the puzzle tasks compared with baseline values (0.36 ± 0.16 vs. 0.26 ± 0.13, P < 0.05) and for the left MCA recordings for the word paradigm (0.48 ± 0.23 vs. 0.29 ± 0.16, P < 0.05). In the same frequency range, significant increases in gain were observed during the puzzle paradigm for the right (0.69 ± 0.37 vs. 0.46 ± 0.32 cm·s−1·mmHg−1, P < 0.05) and left (0.61 ± 0.29 vs. 0.45 ± 0.24 cm·s−1·mmHg−1, P < 0.05) hemispheres and during the word tasks for the left hemisphere (0.66 ± 0.31 vs. 0.39 ± 0.15 cm·s−1·mmHg−1, P < 0.01). Significant reductions in phase were observed during activation with the puzzle task for the right (−0.04 ± 1.01 vs. 0.80 ± 0.86 rad, P < 0.01) and left (0.11 ± 0.81 vs. 0.57 ± 0.51 rad, P < 0.05) hemispheres and with the word paradigm for the right hemisphere (0.05 ± 0.87 vs. 0.64 ± 0.59 rad, P < 0.05). Brain activation also led to changes in the temporal pattern of the CBFV step response. We conclude that transfer function analysis suggests important changes in dynamic CA during mental activation tasks.

scholarly journals Dexmedetomidine Weakens Dynamic Cerebral Autoregulation as Assessed by Transfer Function Analysis and the Thigh Cuff Method

2008 ◽  
Vol 109 (4) ◽  
pp. 642-650 ◽  
Author(s):  
Yojiro Ogawa ◽  
Ken-ichi Iwasaki ◽  
Ken Aoki ◽  
Wakako Kojima ◽  
Jitsu Kato ◽  
...  
Keyword(s):  
Steady State ◽  
Transfer Function ◽  
Arterial Pressure ◽  
Cerebral Autoregulation ◽  
Function Analysis ◽  
Low Frequency ◽  
High Dose ◽  
Frequency Range ◽  
Transfer Function Analysis ◽  
Dynamic Cerebral Autoregulation

Background Dexmedetomidine, which is often used in intensive care units in patients with compromised circulation, might induce further severe decreases in cerebral blood flow (CBF) with temporal decreases in arterial pressure induced by various stimuli if dynamic cerebral autoregulation is not improved. Therefore, the authors hypothesized that dexmedetomidine strengthens dynamic cerebral autoregulation. Methods Fourteen healthy male subjects received placebo, low-dose dexmedetomidine (loading, 3 microg x kg(-1) x h(-1) for 10 min; maintenance, 0.2 microg x kg(-1) x h(-1) for 60 min), and high-dose dexmedetomidine (loading, 6 microg x kg(-1) x h(-1) for 10 min; maintenance, 0.4 microg x kg(-1) x h(-1) for 60 min) infusions in a randomized, double-blind, crossover study. After 70 min of drug administration, dynamic cerebral autoregulation was estimated by transfer function analysis between arterial pressure variability and CBF velocity variability, and the thigh cuff method. Results Compared with placebo, steady state CBF velocity and mean blood pressure significantly decreased during administration of dexmedetomidine. Transfer function gain in the very-low-frequency range increased and phase in the low-frequency range decreased significantly, suggesting alterations in dynamic cerebral autoregulation in lower frequency ranges. Moreover, the dynamic rate of regulation and percentage restoration in CBF velocity significantly decreased when a temporal decrease in arterial pressure was induced by thigh cuff release. Conclusion Contrary to the authors' hypothesis, the current results of two experimental analyses suggest together that dexmedetomidine weakens dynamic cerebral autoregulation and delays restoration in CBF velocity during conditions of decreased steady state CBF velocity. Therefore, dexmedetomidine may lead to further sustained reductions in CBF during temporal decreases in arterial pressure.

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