scholarly journals Hypertension and Stroke Cardiovascular Control Evaluation by Analyzing Blood Pressure, Cerebral Blood Flow, Blood Vessel Resistance and Baroreflex

2021 ◽  
Vol 9 ◽  
Author(s):  
Shoou-Jeng Yeh ◽  
Chi-Wen Lung ◽  
Yih-Kuen Jan ◽  
Fang-Chuan Kuo ◽  
Ben-Yi Liau
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Self Regulation ◽  
Cerebrovascular Diseases ◽  
Cardiovascular Control ◽  
Healthy People ◽  
Regulation Mechanism ◽  
Stroke Patients ◽  
Hypertensive Patients

Cardiovascular diseases have been the leading causes of mortality in Taiwan and the world at large for decades. The composition of cardiovascular and cerebrovascular systems is quite complicated. Therefore, it is difficult to detect or trace the related signs of cardiovascular and cerebrovascular diseases. The characteristics and changes in cardiopulmonary system disease can be used to track cardiovascular and cerebrovascular disease prevention and diagnosis. This can effectively reduce the occurrence of cardiovascular and cerebrovascular diseases. This study analyzes the variability in blood pressure, cerebral blood flow velocity and the interaction characteristics using linear and nonlinear approaches in stroke, hypertension and healthy groups to identify the differences in cardiovascular control in these groups. The results showed that the blood pressure and cerebral blood flow of stroke patients and hypertensive patients were significantly higher than those of healthy people (statistical differences (p < 0.05). The cerebrovascular resistance (CVR) shows that the CVR of hypertensive patients is higher than that of healthy people and stroke patients (p < 0.1), indicating that the cerebral vascular resistance of hypertensive patients is slightly higher. From the patient’s blood flow and vascular characteristics, it can be observed that the cardiovascular system is different from those in healthy people. Baroreflex sensitivity (BRS) decreased in stroke patients (p < 0.05). Chaotic analysis revealed that the blood pressure disturbance in hypertensive patients has a higher chaotic behavior change and the difference in initial state sensitivity. Cross-correlation (CCF) analysis shows that as the course of healthy→hypertension→stroke progresses, the maximum CCF value decreases significantly (p < 0.05). That means that blood pressure and cerebral blood flow are gradually not well controlled by the self-regulation mechanism. In conclusion, cardiovascular control performance in hypertensive and stroke patients displays greater variation. This can be observed by the bio-signal analysis. This analysis could identify a measure for detecting and preventing the risk for hypertension and stroke in clinical practice. This is a pilot study to analyze cardiovascular control variation in healthy, hypertensive and stroke groups.

scholarly journals Blood pressure reduction in hypertensive acute ischemic stroke patients does not affect cerebral blood flow

2018 ◽  
Vol 39 (9) ◽  
pp. 1878-1887 ◽  
Author(s):  
Mahesh Kate ◽  
Negar Asdaghi ◽  
Laura C Gioia ◽  
Brian Buck ◽  
Sumit R Majumdar ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Antihypertensive Drugs ◽  
Controlled Trial ◽  
Blood Pressure Reduction ◽  
Stroke Patients ◽  
Before And After

The effect of blood pressure (BP) reduction on cerebral blood flow (CBF) in acute ischemic stroke is unknown. We measured regional CBF with perfusion-weighted MRI before and after BP treatment in a three-armed non-randomized prospective controlled trial. Treatment arm assignment was based on acute mean arterial pressure (MAP). Patients with (MAP) >120 mmHg ( n = 14) were treated with intravenous labetalol and sublingual (SL) nitroglycerin (labetalol group). Those with MAP 100–120 mmHg ( n = 17) were treated with SL nitroglycerin (0.3 mg) (‘NTG Group’) and those with baseline MAP<100 mmHg ( n = 18) were not treated with antihypertensive drugs (untreated group). Forty-nine patients (18 female, mean age 65.3 ± 12.9 years) were serially imaged. Labetalol reduced MAP by 12.5 (5.7–17.7) mmHg, p = 0.0002. MAP remained stable in the NTG (6.0 (0.4–16, p = 0.3) mmHg and untreated groups (−0.3 (−2.3–7.0, p = 0.2) mmHg. The volume of total hypoperfused tissue (CBF<18 ml/100 g/min) did not increase after labetalol (−1.1 ((−6.5)–(−0.2)) ml, p = 0.1), NTG (0 ((−1.5)–4.5) ml, p = 0.72), or no treatment 0.25 ((−10.1)–4.5) ml, p = 0.87). Antihypertensive therapy, based on presenting BP, in acute stroke patients was not associated with an increased volume of total hypoperfused tissue.

scholarly journals The Effects of Gradual Change in Head Positioning on the Relationship between Systemic and Cerebral Haemodynamic Parameters in Healthy Controls and Acute Ischaemic Stroke Patients

2020 ◽  
Vol 10 (9) ◽  
pp. 582
Author(s):  
Eloise Sands ◽  
Louvinia Wong ◽  
Man Y. Lam ◽  
Ronney B. Panerai ◽  
Thompson G. Robinson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Blood Pressure Variability ◽  
Head Position ◽  
Gradual Change ◽  
Healthy Controls ◽  
Stroke Patients ◽  
Head Positioning ◽  
The Relationship

(1) Background: Larger blood pressure variability (BPv) in the first 3 h post-stroke onset increases pathophysiological effects such as infarct size, and leads to greater risk of disability, comorbidities and mortality at 90 days. However, there is limited information on the relationship between systemic and cerebral haemodynamic and variability parameters. (2) Objectives: This study determined the effect of a gradual change in head position (GHP) on cerebral blood flow velocity variability (CBFVv) and mean arterial blood pressure variability (MABPv), in healthy controls and acute ischaemic stroke (AIS) patients. Methods: CBFVv and MABPv were expressed as standard deviation (SD) and coefficient of variation. A total of 16 healthy controls (mean age 57 ± 16 years) were assessed over two visits, 12 ± 8 days apart, and 15 AIS patients (mean age 69 ± 8.5 years) were assessed over three visits (V1: 13.3 ± 6.9 h, V2: 4.9 ± 3.2 days and V3: 93.9 ± 11.5 days post-stroke). (3) Results: In response to GHP, MABPv does not initially increase, but over time MABPv showed a significant increase in response to GHP in AIS (visits 2 and 3) and controls (visit 2). Additionally, in response to GHP in AIS, CBFVv increased in the affected hemisphere. Lastly, in AIS, a significant correlation between CBFVv and MABPv, assessed by SD, was seen in the unaffected hemisphere, whereas this relationship was not demonstrated in the affected hemisphere. (4) Conclusions: To our knowledge, this is the first study to analyse the relationship between CBFVv and MABPv. Shedding light on the effect of head position on the relationship between cerebral blood flow and blood pressure is important to improve our understanding of the underlying effects of cerebral autoregulation impairment. This early mechanistic study provides evidence supporting supine head positioning in healthy controls and stroke patients, through demonstration of a reduction of MABPv and increase in CBFVv.

Using a blood pressure harmonic variability index to monitor the cerebral blood flow condition in stroke patients

Biorheology ◽  
2011 ◽  
Vol 48 (3-4) ◽  
pp. 219-228 ◽  
Author(s):  
Chao-Tsung Chen ◽  
Shih-Min Huang ◽  
Hsin Hsiu ◽  
Wei-Chen Hsu ◽  
Feng-Cheng Lin ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Condition ◽  
Stroke Patients ◽  
Variability Index ◽  
Blood Flow Condition

Abstract TP160: The Increasing Treatment Pressure Of External Counterpulsation Continuously Augments Blood Pressure But Not Cerebral Blood Flow Velocity Of Ischemic Stroke Patients

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
WEN HUA LIN ◽  
Li Xiong ◽  
Jinghao Han ◽  
Thomas Leung ◽  
Yannie Soo ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Ischemic Stroke ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Stroke Patients ◽  
External Counterpulsation ◽  
Treatment Pressure

Background: External counterpulsation (ECP) is a noninvasive method used to augment cerebral perfusion but the optimal use of ECP in ischemic stroke has not been well documented. We aim to investigate the effects of increasing ECP treatment pressure on cerebral blood flow and blood pressure (BP). Methods: We recruited 38 acute ischemic stroke patients with large artery occlusive disease and 20 healthy elderly. Mean cerebral blood flow velocities (CBFV) of bilateral middle cerebral artery were monitored using transcranial dopper. Continuous beat-to-beat BP was measured via finger cuffs. We started ECP treatment pressure from 150mmHg, then gradually increased to 187.5mmHg, 225mmHg and 262.5mmHg. CBFV and BP were recorded before ECP and during each pressure increment respectively for 3 minutes. CBFV data of patients was analyzed based on whether it was ipsilateral or contralateral to the infarct. Results: Median NIHSS of stroke patients was 5.5 and mean time after stroke onset was 5.24 days. Mean BP was significantly elevated from baseline in both groups after ECP started. BP increase percentages of two groups similarly kept augmented following raised ECP pressure and reach maximium at 262.5mmHg (patients 16.9% vs. controls 16.52% compared with baseline). Under different ECP pressures, ipsilateral mean CBFV of stroke patients increased 5.15% (150mmHg), 4.35% (187.5mmHg), 4.55% (225mmHg) and 3.52% (262.5mmHg) from baseline. All were significantly higher than baseline but did not differ among different pressures. Contralateral mean CBFV changed likewise (5.16%, 4.02%, 3.7% and 3.34% increase from baseline). Mean CBFV of controls under ECP pressures did not increase from baseline. Conclusion: The increasing treatment pressure of external counterpulsation continuously augments blood pressure but not cerebral blood flow velocity of ischemic stroke patients with large artery occlusive disease. Cerebral blood flow velocity of stroke patients significantly increases from baseline under ECP pressure of 150mmHg but it reaches a plateau as ECP pressure further raises. Among 4 ECP pressures above, 150mmHg is the optimal treatment pressure for ischemic stroke due to higher risks of hypertension-related complications in acute stroke with higher ECP pressure.

Patterns of Cerebral Blood Flow and Systemic Hemodynamics During Arithmetic Processing

2008 ◽  
Vol 22 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Natalie Werner ◽  
Neval Kapan ◽  
Gustavo A. Reyes del Paso
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Time Course ◽  
Doppler Sonography ◽  
Transcranial Doppler Sonography ◽  
Systemic Hemodynamics ◽  
Heart Period ◽  
Blood Flow Velocities ◽  
Flow Velocities

The present study explored modulations in cerebral blood flow and systemic hemodynamics during the execution of a mental calculation task in 41 healthy subjects. Time course and lateralization of blood flow velocities in the medial cerebral arteries of both hemispheres were assessed using functional transcranial Doppler sonography. Indices of systemic hemodynamics were obtained using continuous blood pressure recordings. Doppler sonography revealed a biphasic left dominant rise in cerebral blood flow velocities during task execution. Systemic blood pressure increased, whereas heart period, heart period variability, and baroreflex sensitivity declined. Blood pressure and heart period proved predictive of the magnitude of the cerebral blood flow response, particularly of its initial component. Various physiological mechanisms may be assumed to be involved in cardiovascular adjustment to cognitive demands. While specific contributions of the sympathetic and parasympathetic systems may account for the observed pattern of systemic hemodynamics, flow metabolism coupling, fast neurogenic vasodilation, and cerebral autoregulation may be involved in mediating cerebral blood flow modulations. Furthermore, during conditions of high cardiovascular reactivity, systemic hemodynamic changes exert a marked influence on cerebral blood perfusion.

Cerebral Blood Flow and Blood Pressure

2019 ◽  
Vol 47 (7) ◽  
pp. 1007-1009
Author(s):  
Douglas S. DeWitt ◽  
Donald S. Prough
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow

Diurnal variation in time to presyncope and associated circulatory changes during a controlled orthostatic challenge

2010 ◽  
Vol 299 (1) ◽  
pp. R55-R61 ◽  
Author(s):  
N. C. S. Lewis ◽  
G. Atkinson ◽  
S. J. E. Lucas ◽  
E. J. M. Grant ◽  
H. Jones ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Diurnal Variation ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Orthostatic Challenge ◽  
Arterial Blood ◽  
Neurally Mediated Syncope

Epidemiological data indicate that the risk of neurally mediated syncope is substantially higher in the morning. Syncope is precipitated by cerebral hypoperfusion, yet no chronobiological experiment has been undertaken to examine whether the major circulatory factors, which influence perfusion, show diurnal variation during a controlled orthostatic challenge. Therefore, we examined the diurnal variation in orthostatic tolerance and circulatory function measured at baseline and at presyncope. In a repeated-measures experiment, conducted at 0600 and 1600, 17 normotensive volunteers, aged 26 ± 4 yr (mean ± SD), rested supine at baseline and then underwent a 60° head-up tilt with 5-min incremental stages of lower body negative pressure until standardized symptoms of presyncope were apparent. Pretest hydration status was similar at both times of day. Continuous beat-to-beat measurements of cerebral blood flow velocity, blood pressure, heart rate, stroke volume, cardiac output, and end-tidal Pco2 were obtained. At baseline, mean cerebral blood flow velocity was 9 ± 2 cm/s (15%) lower in the morning than the afternoon ( P < 0.0001). The mean time to presyncope was shorter in the morning than in the afternoon (27.2 ± 10.5 min vs. 33.1 ± 7.9 min; 95% CI: 0.4 to 11.4 min, P = 0.01). All measurements made at presyncope did not show diurnal variation ( P > 0.05), but the changes over time (from baseline to presyncope time) in arterial blood pressure, estimated peripheral vascular resistance, and α-index baroreflex sensitivity were greater during the morning tests ( P < 0.05). These data indicate that tolerance to an incremental orthostatic challenge is markedly reduced in the morning due to diurnal variations in the time-based decline in blood pressure and the initial cerebral blood flow velocity “reserve” rather than the circulatory status at eventual presyncope. Such information may be used to help identify individuals who are particularly prone to orthostatic intolerance in the morning.

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