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Hypertension Research : Official... Jun 2022Pulse transit time (PTT), which refers to the travel time between two arterial sites within the same cardiac cycle, has been developed as a novel cuffless form of...
Pulse transit time (PTT), which refers to the travel time between two arterial sites within the same cardiac cycle, has been developed as a novel cuffless form of continuous blood pressure (BP) monitoring. The aim of this study was to investigate differences in BP parameters, including BP variability, between those assessed by beat-to-beat PTT-estimated BP (eBP) and those assessed by intermittent PTT-estimated BP at fixed time intervals (eBP) in patients suspected of having sleep disordered breathing (SDB). In 330 patients with SDB (average age, 66.8 ± 11.9 years; 3% oxygen desaturation index [ODI], 21.0 ± 15.0/h) from 8 institutes, PTT-estimated BP was continuously recorded during the nighttime. The average systolic eBP, maximum systolic and diastolic eBP, standard deviation (SD) of systolic and diastolic eBP, and coefficient variation (CV) of systolic and diastolic eBP were higher than the respective values of eBP (all P < 0.05). Bland-Altman analysis showed a close agreement between eBP and eBP in average systolic BP and SD and CV of systolic BP, while there were disagreements in both minimum and maximum values of eBP and eBP in patients with high systolic BP (P < 0.05). Although systolic BP variability incrementally increased according to the tertiles of 3%ODI in both eBP and eBP (all P < 0.05), there was no difference in this tendency between eBP and eBP. In patients with suspected SDB, the difference between eBP and eBP was minimal, and there were disagreements regarding both the minimum and maximum BP. However, there were agreements in regard to the index of BP variability between eBP and eBP.
Topics: Aged; Blood Pressure; Blood Pressure Determination; Humans; Middle Aged; Pulse Wave Analysis; Sleep Apnea Syndromes; Systole
PubMed: 35388176
DOI: 10.1038/s41440-022-00899-z -
IEEE Transactions on Bio-medical... Feb 2023Oscillogram modeling is a powerful tool for understanding and advancing popular oscillometric blood pressure (BP) measurement. A reduced oscillogram model relating cuff...
OBJECTIVE
Oscillogram modeling is a powerful tool for understanding and advancing popular oscillometric blood pressure (BP) measurement. A reduced oscillogram model relating cuff pressure oscillation amplitude ( ∆O) to external cuff pressure of the artery ( P) is: [Formula: see text], where g(P) is the arterial compliance versus transmural pressure ( P) curve, P and P are systolic and diastolic BP, and k is the reciprocal of the cuff compliance. The objective was to determine an optimal functional form for the arterial compliance curve.
METHODS
Eight prospective, three-parameter functions of the brachial artery compliance curve were compared. The study data included oscillometric arm cuff pressure waveforms and invasive brachial BP from 122 patients covering a 20-120 mmHg pulse pressure range. The oscillogram measurements were constructed from the cuff pressure waveforms. Reduced oscillogram models, inputted with measured systolic and diastolic BP and each parametric brachial artery compliance curve function, were optimally fitted to the oscillogram measurements in the least squares sense.
RESULTS
An exponential-linear function yielded as good or better model fits compared to the other functions, with errors of 7.9±0.3 and 5.1±0.2% for tail-trimmed and lower half-trimmed oscillogram measurements. Importantly, this function was also the most tractable mathematically.
CONCLUSION
A three-parameter exponential-linear function is an optimal form for the arterial compliance curve in the reduced oscillogram model and may thus serve as the standard function for this model henceforth.
SIGNIFICANCE
The complete, reduced oscillogram model determined herein can potentially improve oscillometric BP measurement accuracy while advancing foundational knowledge.
Topics: Humans; Blood Pressure; Prospective Studies; Blood Pressure Determination; Arterial Pressure; Brachial Artery
PubMed: 36006885
DOI: 10.1109/TBME.2022.3201433 -
Acta Neurochirurgica Dec 2021The pulse waveform of intracranial pressure (ICP) is its distinctive feature almost always present in the clinical recordings. In most cases, it changes proportionally...
BACKGROUND
The pulse waveform of intracranial pressure (ICP) is its distinctive feature almost always present in the clinical recordings. In most cases, it changes proportionally to rising ICP, and observation of these changes may be clinically useful. We introduce the higher harmonics centroid (HHC) which can be defined as the center of mass of harmonics of the ICP pulse waveform from the 2nd to 10th, where mass corresponds to amplitudes of these harmonics. We investigate the changes in HHC during ICP monitoring, including isolated episodes of ICP plateau waves.
MATERIAL AND METHODS
Recordings from 325 patients treated between 2002 and 2010 were reviewed. Twenty-six patients with ICP plateau waves were identified. In the first step, the correlation between HHC and ICP was examined for the entire monitoring period. In the second step, the above relation was calculated separately for periods of elevated ICP during plateau wave and the baseline.
RESULTS
For the values averaged over the whole monitoring period, ICP (22.3 ± 6.9 mm Hg) correlates significantly (R = 0.45, p = 0.022) with HHC (3.64 ± 0.46). During the ICP plateau waves (ICP increased from 20.9 ± 6.0 to 53.7 ± 9.7 mm Hg, p < 10), we found a significant decrease in HHC (from 3.65 ± 0.48 to 3.21 ± 0.33, p = 10).
CONCLUSIONS
The good correlation between HHC and ICP supports the clinical application of pressure waveform analysis in addition to the recording of ICP number only. Mean ICP may be distorted by a zero drift, but HHC remains immune to this error. Further research is required to test whether a decline in HHC with elevated ICP can be an early warning sign of intracranial hypertension, whether individual breakpoints of correlation between ICP and its centroid are of clinical importance.
Topics: Blood Pressure; Heart Rate; Humans; Intracranial Hypertension; Intracranial Pressure; Monitoring, Physiologic
PubMed: 34387744
DOI: 10.1007/s00701-021-04958-1 -
International Journal of Environmental... Mar 2020There is paucity of studies on the association between pulse pressure and the development of dementia, although this association has already been established. This...
There is paucity of studies on the association between pulse pressure and the development of dementia, although this association has already been established. This study aimed at investigating the association between pulse pressure and the onset of dementia. We used the South Korean National Health Insurance Service claims cohort data to select 149,663 patients without dementia aged ≥60 years. We calculated adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for dementia using Cox proportional hazard models according to a pulse pressure classification (<50, 50-59, 60-69, 70-79, 80-89, or 90+). Compared to women with pulse pressure <50, those with pulse pressures of 50-59, 60-69, and 90+ had higher HRs for dementia (1.14, 1.22, and 1.03, respectively). These associations were particularly strong in those on Medicaid insurance and from rural regions. However, there were no statistically significant results among men. A higher pulse pressure was associated with an elevated risk of dementia in women aged >60 years, particularly those on Medicaid and from rural regions, possibly due to their inability to access hypertension and other medical treatment. The establishment of dementia indicators will help to guide future health policies for the prevention of dementia.
Topics: Aged; Blood Pressure; Cohort Studies; Dementia; Female; Humans; Male; Middle Aged; Proportional Hazards Models; Republic of Korea; Risk Factors
PubMed: 32143342
DOI: 10.3390/ijerph17051657 -
Ultrasound in Medicine & Biology Sep 2023The precise mechanism and determinants of brain tissue pulsations (BTPs) are poorly understood, and the impact of blood pressure (BP) on BTPs is relatively unexplored....
OBJECTIVE
The precise mechanism and determinants of brain tissue pulsations (BTPs) are poorly understood, and the impact of blood pressure (BP) on BTPs is relatively unexplored. This study aimed to explore the relationship between BP parameters (mean arterial pressure [MAP] and pulse pressure [PP]) and BTP amplitude, using a transcranial tissue Doppler prototype.
METHODS
A phantom brain model generating arterial-induced BTPs was developed to observe BP changes in the absence of confounding variables and cerebral autoregulation feedback processes. A regression model was developed to investigate the relationship between bulk BTP amplitude and BP. The separate effects of PP and MAP were evaluated and quantified.
RESULTS
The regression model (R = 0.978) revealed that bulk BTP amplitude measured from 27 gates significantly increased with PP but not with MAP. Every 1 mm Hg increase in PP resulted in a bulk BTP amplitude increase of 0.29 µm.
CONCLUSION
Increments in BP were significantly associated with increments in bulk BTP amplitude. Further work should aim to confirm the relationship between BP and BTPs in the presence of cerebral autoregulation and explore further physiological factors having an impact on BTP measurements, such as cerebral blood flow volume, tissue distensibility and intracranial pressure.
Topics: Blood Pressure; Brain; Intracranial Pressure; Arteries; Ultrasonography, Doppler, Transcranial; Cerebrovascular Circulation
PubMed: 37400302
DOI: 10.1016/j.ultrasmedbio.2023.06.005 -
Ethnicity & Disease 2021The incidence of younger women being hospitalized from cardiovascular disease (CVD) events is on the rise. Hispanic women are generally thought to have higher CVD risk...
BACKGROUND
The incidence of younger women being hospitalized from cardiovascular disease (CVD) events is on the rise. Hispanic women are generally thought to have higher CVD risk factor burden than non-Hispanic White (NHW) women yet Hispanic Americans have lower mortality from CVD. Traditional measures of CVD may not accurately capture CVD risk in Hispanic Americans. Hence, the purpose of this study was to assess the impact of ethnicity on vascular reactivity and central hemodynamic load to gain insight into subclinical CVD risk in young women.
METHODS
Brachial flow-mediated dilation (FMD), low-flow mediated constriction (L-FMC), carotid-femoral pulse wave velocity (cfPWV), and pulse wave analysis (from synthesized aortic pressure waveforms) were measured in 25 Hispanic women and 31 NHW women aged between 18-35 years. FMD and L-FMC were combined to provide an index of total vessel reactivity.
RESULTS
NHW and Hispanic women did not differ in age or traditional CVD risk factors (P>.05 for all). Compared with NHW women, Hispanic women had greater vascular reactivity (8.7±4.1 vs 11.7±4.1 %, P=.011), lower central pulse pressure (28±5 vs 24±3 mm Hg, P=.001) and lower pressure from wave reflections (12±2 vs 10±1 mm Hg, P=.001). There were no differences in cfPWV between NHW women and Hispanic women (5.4±0.7 vs 5.3±0.7 m/s, P=.73).
CONCLUSION
Young Hispanic women have greater vascular reactivity and lower central pulsatile hemodynamic load compared with NHW women, suggesting lower subclinical CVD risk.
Topics: Adolescent; Adult; Blood Pressure; Brachial Artery; Cardiovascular Diseases; Female; Hispanic or Latino; Humans; Pulse Wave Analysis; Risk Factors; Vascular Stiffness; Young Adult
PubMed: 34720552
DOI: 10.18865/ed.31.4.489 -
Remote Estimation of Blood Pressure Using Millimeter-Wave Frequency-Modulated Continuous-Wave Radar.Sensors (Basel, Switzerland) Jul 2023This paper proposes to remotely estimate a human subject's blood pressure using a millimeter-wave radar system. High blood pressure is a critical health threat that can...
This paper proposes to remotely estimate a human subject's blood pressure using a millimeter-wave radar system. High blood pressure is a critical health threat that can lead to diseases including heart attacks, strokes, kidney disease, and vision loss. The commonest method of measuring blood pressure is based on a cuff that is contact-based, non-continuous, and cumbersome to wear. Continuous remote monitoring of blood pressure can facilitate early detection and treatment of heart disease. This paper investigates the possibility of using millimeter-wave frequency-modulated continuous-wave radar to measure the heart blood pressure by means of pulse wave velocity (PWV). PWV is known to be highly correlated with blood pressure, which can be measured by pulse transit time. We measured PWV using a two-millimeter wave radar focused on the subject's chest and wrist. The measured time delay provided the PWV given the length from the chest to the wrist. In addition, we analyzed the measured radar signal from the wrist because the shape of the pulse wave purveyed information on blood pressure. We investigated the area under the curve (AUC) as a feature and found that AUC is strongly correlated with blood pressure. In the experiment, five human subjects were measured 50 times each after performing different activities intended to influence blood pressure. We used artificial neural networks to estimate systolic blood pressure (SBP) and diastolic blood pressure (SBP) with both PWV and AUC as inputs. The resulting root mean square errors of estimated blood pressure were 3.33 mmHg for SBP and 3.14 mmHg for DBP.
Topics: Humans; Blood Pressure; Radar; Pulse Wave Analysis; Vital Signs; Blood Pressure Determination
PubMed: 37514810
DOI: 10.3390/s23146517 -
Experimental Gerontology Mar 2023One of the hallmarks of vascular aging is increased pulse pressure. This elevated pulse pressure is associated with deleterious effects on cerebral vascular function;...
One of the hallmarks of vascular aging is increased pulse pressure. This elevated pulse pressure is associated with deleterious effects on cerebral vascular function; however, it is unknown if age modulates the susceptibility to high pulse pressure. To examine the effects of age on the cerebral artery response to pulse pressure, we studied isolated cerebral arteries collected from young (6.1 ± 0.2 mo) and old (26.7 ± 0.5 mo) male C57BL/6 mice. Isolated cerebral arteries were exposed ex vivo to static pressure, low pulse pressure (25 mmHg), and high pulse pressure (50 mmHg). In cerebral arteries from young mice, endothelium-dependent dilation was similar between the static and low pulse pressure conditions. Exposure to high pulse pressure impaired endothelium-dependent dilation in cerebral arteries from young mice, mediated by less nitric oxide bioavailability and greater oxidative stress. Cerebral arteries from old mice had impaired cerebral artery endothelium-dependent dilation at static pressure compared with young cerebral arteries. However, exposure to low or high pulse pressure did not cause any further impairments to endothelium-dependent dilation in old cerebral arteries compared with static pressure. The old cerebral arteries had less distension during exposure to high pulse pressure and greater stiffness compared with young cerebral arteries. These results indicate that acute exposure to high pulse pressure impairs endothelium-dependent dilation in young, but not old, cerebral arteries. The greater stiffness of cerebral arteries from old mice potentially protects against the negative consequences of high pulse pressure.
Topics: Mice; Male; Animals; Blood Pressure; Vasodilation; Mice, Inbred C57BL; Cerebral Arteries; Aging; Endothelium, Vascular
PubMed: 36690049
DOI: 10.1016/j.exger.2023.112101 -
Effects of exercise on the cardiovascular function of rats in a sulfur dioxide polluted environment.Anais Da Academia Brasileira de Ciencias 2022The purpose of the study is to further explore the combined effects of exercise and sulfur dioxide (SO2) exposure on the cardiovascular function as well as the...
The purpose of the study is to further explore the combined effects of exercise and sulfur dioxide (SO2) exposure on the cardiovascular function as well as the underlying mechanisms. Rats were randomly divided into 4 groups: rest group (RG), exercise group (EG), SO2 pollution group (SG) and SO2 pollution + exercise group (SEG). Changes of aortic pressure and left ventricular pressure, Ang II concentration, ACE concentration and ACE activity in rats' myocardial tissue were observed. Compared with RG, the systolic blood pressure, pulse pressure, LVSP, +dp/dtmax and -dp/dtmax of EG increased significantly, diastolic blood pressure, resting heart rate and ACE activity decreased significantly; For rats of SG, 4 weeks SO2 exposure increased LVEDP, Ang II concentration, ACE concentration and ACE activity, decreased the +dp/dtmax and -dp/dtmax; For rats of SEG, the systolic blood pressure, pulse pressure, LVSP, +dp/dtmax and -dp/dtmax decreased significantly, HR, LVEDP, Ang II concentration, ACE concentration and ACE activity increased significantly. Results indicate that, the combination of aerobic exercise and SO2 exposure can aggravate the negative effects of SO2 inhalation on cardiovascular function. Renin-angiotensin system plays an important role in mediating the negative effect of SO2 inhalation.
Topics: Animals; Blood Pressure; Myocardium; Rats; Sulfur Dioxide
PubMed: 35674607
DOI: 10.1590/0001-3765202220211180 -
Frontiers in Public Health 2023Transitioning from marriage to widowhood presents inevitable and significant challenges for many older adults. This study explored the impact of widowhood on a range of...
BACKGROUND
Transitioning from marriage to widowhood presents inevitable and significant challenges for many older adults. This study explored the impact of widowhood on a range of mental health outcomes, including pulse pressure and fasting blood glucose levels, among older adults in nursing homes.
METHODS
This cross-sectional study utilized cluster random sampling to recruit participants, with data analyzed from 388 older Chinese adults. Psychosocial traits were assessed using the Perceived Social Support from Family scale (PSS-Fa) for family support, the Generalized Anxiety Disorder 7-item scale (GAD-7) for anxiety symptoms, and the 9-item Patient Health Questionnaire (PHQ-9) for depressive symptoms and suicidal ideation. Propensity score matching (PSM) was employed to control for confounding factors. A multivariate linear regression analysis was performed to explore the relationship between widowhood, mental health outcomes, pulse pressure, and fasting blood glucose levels.
RESULTS
After applying PSM, the sample size was refined to 268 ( = 134 for both married and widowed groups) from the initial 388, excluding 120 unmatched cases. Widowed older adults were found to have notably lower family support ( = -0.81, = 0.002), increased depressive symptoms ( = 1.04, = 0.043), elevated pulse pressure ( = 8.90, < 0.001), and higher fasting blood glucose levels ( = 3.22, = 0.027). These associations exhibited greater beta values compared to pre-matching analysis.
CONCLUSION
Our findings revealed that widowed participants had reduced family support, an increased risk of depressive symptoms, heightened pulse pressure, and elevated fasting blood glucose in comparison to their married counterparts. Interventions focusing on social support, mental health, and cardiovascular well-being could be advantageous for this at-risk group.
Topics: Female; Humans; Middle Aged; Aged; Widowhood; Blood Glucose; Mental Health; Blood Pressure; Cross-Sectional Studies; Propensity Score
PubMed: 37954046
DOI: 10.3389/fpubh.2023.1257133