Pressure Variability Research Articles

Beat-to-beat analysis of hemodynamic response to mental and psychological stress in sickle cell anemia

Abstract Objectives Vaso-occlusive crises are a hallmark symptom of SCD. Physical stressors can trigger decreased microvascular blood flow and increase the risk for vaso-occlusive crises. However, the effect of mental and psychological stressors on vascular physiology in SCD is not well-established. We hereby examined fluctuations in continuous blood pressure to evaluate hemodynamic changes in SCD patients during mental and psychological stress. Methods Thirteen SCD subjects from the Children’s Hospital Los Angeles and 11 healthy volunteers were recruited. Continuous blood pressure was recorded during 2 mental tasks and 1 psychological stress task. Systolic beat-to-beat blood pressure variability measurements were calculated for each subject. Three very short-term blood pressure variability metrics served as outcome measures: SD, coefficient of variation, and average real variability. Peripheral augmentation index was calculated from arterial waveforms. Linear mixed effects models evaluated associations between patient factors and outcome measures. Results SCD patients exhibit increased systolic blood pressure variability in response to psychological stress. All subjects exhibited a decrease in systolic blood pressure variability in response to mental stress tasks. During mental stress, both groups displayed increased augmentation index, reflective of stress-induced vasoconstriction, while psychological stress in SCD patients led to both decreased mean arterial pressure and increased augmentation index, suggestive of uncompensated vasoconstriction. Conclusion These findings emphasize the impact of mental and psychological stressors on vascular function in SCD and the potential for monitoring physiological signals to predict vaso-occlusive crisis events.

Design and implementation of digital home blood pressure monitoring based on Bluetooth and WeChat App in the FAIR-Pilot study

Abstract Background Home blood pressure monitoring (HBPM) could be an alternative way to office blood pressure and ambulatory blood pressure monitoring for hypertensive patient management. However, the measurement protocol of HBPM still requires standardization, which may be improved by digital technology. Purpose To investigate the use of digital HBPM management in hypertensive patients and its application in clinical practice. Methods Fractional Flow Reserve to Determine the Appropriateness of Percutaneous Renal Artery Intervention in Atherosclerosis Renal Hypertension Patients (FAIR)-pilot study is a multicenter pilot randomized controlled trial exploring the application of fractional flow reserve (FFR) to guide the renal artery stenting in patients with renovascular hypertension. After randomization and FFR measurement, participants were divided into stenting with FFR≥ 0.8 (Stent group), no stent implantation with FFR≥ 0.8 (No stent group), and stenting with FFR＜ 0.8 (Controlled group). Participants of the FAIR-pilot study enrolled from February 1st, 2023 to February 25th, 2024 were included. A validated Bluetooth blood pressure monitor was given to every participant at the time of enrollment. Participants were taught to undertake standardized HBP and were advised to take morning and night HBPs every day. HBPM data were automatically uploaded to a WeChat App developed by FAIR investigators and could be reviewed by both participants and investigators. Twice-daily blood pressure reports were automatically generated and sent to investigators for participant compliance monitoring and reminding (Figure 1). HBPM data and blood pressure variability were analyzed. Results A total of 93 participants with 58 males (62.4%) and a mean age of 59.97 ± 16.18 years, including 26,802 HBP readings were analyzed. The average numbers of daily HBP measurement were similar between three groups and were all less than twice a day. Systolic HBP decreased from 143.11 ± 14.91 to 133.01 ± 13.01mmHg after the procedure in the Controlled group, which was more than the other two groups (140.51 ± 13.38 to 138.53 ± 17.30 mmHg and 136.20 ± 15.67 to 130.84 ± 11.04 mmHg). During the follow-up after the procedure, the HBP variability (BPV) of overall participants was 13.78 ± 4.87 and 5.46 ± 3.14 for systolic and diastolic BP, respectively. The systolic BPV of No stent group was higher than the other two groups (No stent vs. Stent vs. Controlled: 33.00 ± 9.49 vs. 8.34 ± 2.86 vs. 9.12 ± 2.71, P=0.125), however without statistical significance. Similar was found for morning and night systolic BPVs. (Table 1). Conclusion Digital HBPM management via novel information technology is feasible in the hypertension field and could be a helpful tool in clinical practice.

Relationships among intensive blood pressure control, morning blood pressure surge and 24-hour blood pressure variability

Abstract Objectives This study aimed to investigate the relationships between cardiovascular outcomes and blood pressure (BP) reduction, 24-hour BP variability (BPV), morning BP surge (MBPS), and visit-to-visit BPV. Methods This study involved 897 participants from the Systolic Blood Pressure International Trial (SPRINT), for whom biochemical and demographic data, medication history, and various blood profile information were collected. Univariate and multivariate linear regression models were used to assess the impact of intensive BP management on 24-hour BPV and the MBPS. Results Among the 897 participants (average age 71.48 ± 9.42 years; 640 males), 453 received intensive treatment. Those in the intensive group were more likely to be on ACE inhibitors, CCBs, or diuretics. This group showed significant reductions in 24-hour systolic and diastolic BP, as well as in both short-term and long-term BPVs, such as average real variability (ARV) and MBPS. The analysis demonstrated strong associations between intensive BP management and improvements in various BPV measures, including systolic ARV, diastolic BP ARV, and cumulative BP loads. A significant correlation was also found between intensive BP lowering and the primary composite outcome of the SPRINT study. Conclusions This study highlighted the significant associations between intensive BP management and reductions in the MBPS and 24-hour BPV, which affect both short-term and long-term health outcomes. The primary benefits of intensive BP control appear to stem from direct BP reduction rather than changes in BPV. However, further extensive randomized controlled trials are needed to confirm these findings.

Cardiac morphology and function in patients with primary biliary cholangitis (PBC) without cirrhosis

Abstract Background Primary biliary cholangitis (PBC) is a chronic, autoimmune liver disease causing destruction of the small intralobular bile ducts in the liver. PBC patients can also develop extrahepatic manifestations. Though patients with PBC have often elevated levels of serum lipids, data concerning cardiac involvement is inconsistent and cardiovascular changes may be underdiagnosed. Purpose The purpose of the study was to assess cardiac morphology and function in patients with PBC without cirrhosis and comparison with control subjects. Methods We studied 52 females with PBC, and included in the analysis 22 females without cirrhosis, who were compared to 44 healthy female controls matched for age (53.4 ± 9.2 and 51 ± 8.3 yrs., respectively, p =0.312). Transthoracic echocardiography (TTE) was performed with the analysis of the left ventricular (LV) global longitudinal strain (GLS) and myocardial work. Additionally, impedance cardiography was conducted, with the analysis of the autonomic function using BRS (baroreceptor sensitivity), HRV (heart rate variability) and BPV (blood pressure variability). Results Systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) differed between PBC and control group (128 ± 17 mmHg vs. 116 ± 11 mmHg, p=0.007 and 78± 12 mmHg vs. 75 ± 8 mmHg, p=0.024, and 73.5 ± 12 bpm vs. 71 ± 8 bpm , p=0.024, respectively). PBC group had larger diameter of the cardiac chambers when adjusted for body surface area (BSA), including left atrium (LA/BSA) and right ventricle (RV/BSA), as well as left ventricular mass (LWMI) and relative wall thickness (RWT), with no difference in the left ventricular end diastolic diameter (LVEDD/BSA). LV ejection fraction (EF) measured by bi-plane Simpson method was higher in PBC group. LV diastolic function parameters (E/A, E/e’) differed in patients with PBC when compared with controls, however, without signs of diastolic dysfunction. LV GLS indices (GLSAVG, GLSLAX, GLS4C, GLS2C) were significantly higher in PBC group, as well as global myocardial work indexes: global myocardial work (GWI) and global constructive work (GCW). Non-invasive autonomic assessment showed lower BPV in patients with PBC without cirrhosis, but no differences in baroreceptor sensitivity and HRV. Impedance cardiography did not show differences between both groups. Conclusion Our study shows that PBC patients without cirrhosis are characterized by remodeling and functional changes of the heart, when compared to age-matched controls. These changes could imply hyperkinetic circulation even before the development of cirrhosis in PBC patients.

Atypical posterior reversible encephalopathy syndrome following craniotomy for a metastatic lesion: illustrative case.

An 80-year-old male was found to have a metastatic lesion in his cerebrum. He underwent uncomplicated resection with prolonged inhalational anesthesia due to issues with intravenous access prior to surgery. Postoperatively, the patient had persistent altered mental status. Immediate postoperative head computed tomography and continuous electroencephalography were negative for possible causes. Standard brain magnetic resonance imaging (MRI) after metastatic resection demonstrated the development of edema in his pons and thalami, concerning for posterior reversible encephalopathy syndrome (PRES). Tight blood pressure control was initiated. His neurological examination returned to baseline. Follow-up MRI showed the resolution of edema. This is a report of PRES hypothesized to be attributable to prolonged inhalational anesthetic. PRES is a disorder in which patients present with altered mentation, seizures, visual impairment, or headache. PRES often occurs due to acute uncontrolled hypertension; however, other conditions, including autoimmune disease and cancer chemotherapy, have been linked. In severe cases, permanent brain damage and death have been reported. The authors present a case of PRES as the cause of severe neurological decline following craniotomy without severe or sustained hypertension. The authors hypothesize that PRES could be caused by blood pressure variability in the perioperative period and prolonged anesthesia. https://thejns.org/doi/10.3171/CASE24245.

Optimizing the Migratory Environment of Wildebeests in the Maasai Mara Reserve with a New Ecological Corridor and Customized Buffer Zone Model

Conflicts between wildlife and humans are a major ecological issue. During migration, wildlife, especially wildebeest, often encounter significant environmental pressures from human activities. However, relatively few studies have been conducted to provide a concise, quantitative description of wildebeest migration in the Maasai Mara National Reserve (MMNR). In this study, we identified changes in the location of the wildebeest population over time in the Maasai Mara National Reserve. We then used a K-means algorithm (R2 = 0.926) to fit coordinates representing the changes in the location of the wildebeests to enable a quantitative representation of their migration routes. Subsequently, we developed an environmental stress model to assess the changes in environmental stresses faced by wildebeests along their migration routes. We proposed a model of “migratory ecological corridors and customized buffer zones” and determined the response coefficient T_res. We used the response coefficients T_res = 0.06, 0.09, and 0.12 as the critical values to categorize the areas along the routes into weak, medium, and strong response regions. Then, we set the width of the buffer zones on both sides of the routes as 5 km, 7 km, and 9 km, respectively, and evaluated the buffer effect. This type of model achieved a good effect of reducing the environmental pressure by 54.06%. The “Migratory Ecological Corridor and Customized Buffer Zone” model demonstrated a high degree of economic feasibility while showing good practicality in mitigating the environmental conflicts between humans and migratory wildlife. The variability in the environmental pressures across the region indicates that the Nairobi and Nakuru districts may be undergoing a particular stage of urbanization that unleashes potential threats to the migration of wildebeests. Further research is essential to assess the feasibility of larger buffer zones.

The Impact of Blood Pressure Rhythm and Perioperative Blood Pressure Variability on Short-Term Prognosis in Patients with Type A Aortic Dissection.

Aims/Background Previous studies have indicated a strong correlation between disturbances in blood pressure (BP) circadian rhythm and major cardiovascular adverse events. Similarly, blood pressure variability (BPV) has been closely linked to cerebral small vessel disease and leukoaraiosis. This study aims to investigate the relationship between BP rhythm and BPV with the short-term prognosis of patients with Type A aortic dissection, offering insights for targeted perioperative nursing interventions and improving patient outcomes. Methods This retrospective study included patients undergoing surgical treatment for Type A aortic dissection at Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences) from June 2022 to March 2024. The study followed patients from the completion of surgery to 30 days postoperatively, with all-cause mortality within 30 days as the endpoint representing poor short-term prognosis. Clinical data were compared along with: types of BP rhythm; BPV parameters including the mean 24-hour systolic BP (24hSBP), 24-hour diastolic BP (24hDBP), and pulse pressure; and the coefficient of variability (CV) for 24hSBP, 24hDBP, and pulse pressure. Multivariate logistic regression analysis was utilized to identify risk factors for poor short-term outcomes in these patients, and receiver operating characteristic (ROC) curves were plotted to assess the predictive value of BP rhythm types and BPV indicators. Results The study ultimately included 115 participants, with 31 deaths occurring within 30 days post-surgery, resulting in a postoperative mortality rate of 26.96%. The multivariate logistic regression analysis revealed that white blood cell count, neutrophil count, non-dipping BP rhythm, pulse pressure, and the CV for 24hSBP, 24hDBP, and pulse pressure, were significant risk factors for poor short-term prognosis (p < 0.05). The ROC curve analysis demonstrated that non-dipping BP rhythm, pulse pressure, 24hSBP-CV, 24hDBP-CV, and pulse pressure-CV had areas under the curve (AUC) of 0.685, 0.749, 0.751, 0.773, and 0.763, respectively. The combination of these indicators yielded the highest AUC at 0.918. Conclusion A combination of BP rhythm and BPV indicators provides significant predictive value for poor short-term outcomes in patients with Type A aortic dissection. Clinicians and nursing staff can use these features to formulate targeted preventive measures.

The impact of salt consumption on cardiometabolic and cognitive health in aged female rats

Health concerns about excess dietary salt have traditionally focused on its relationship with hypertension and the increased risk of cognitive impairment. However, research has often overlooked the unique health concerns and physiological differences between men and women, leading to gaps in knowledge, particularly regarding disease prevention and treatment strategies for women. The present study examined aged female rats over 12 weeks, using control, low, and high salt diets to mimic the post-menopausal phase in human females when cardiovascular risks typically increase. Cardiometabolic parameters and cognition were monitored. The findings revealed the impact of varying salt diets on blood lipids, blood pressure (BP) and heart rate (HR) levels and variability, anxiety, and cognition. Specifically, intake of a low-salt diet led to a significant reduction in BP levels but an increase in BP variability starting from the eighth week of the diet onset. Moreover, HR levels and variability were notably higher with the low-salt diet. Aged female rats exhibited increased anxiety on the low-salt diet at the fourth week, but the anxiety began to improve starting from the eighth week. Additionally, a trend suggested that the low salt intake worsened short-term memory while improving long-term memory. Furthermore, plasma lipids decreased significantly in aged female rats on a high-salt diet compared to those on a low-salt diet. The study provides valuable insights into the effects of salt intake on cardiometabolic parameters and cognitive function in aged female rats, highlighting the importance of considering sex-specific dietary guidelines for cardiometabolic and cognitive health.

Blood pressure variability compromises vascular function in middle-aged mice.

Blood pressure variability (BPV) has emerged as a novel risk factor for cognitive decline and dementia, independent of alterations in average blood pressure (BP). However, the underlying consequences of large BP fluctuations on the neurovascular complex are unknown. We developed a novel mouse model of BPV in middle-aged mice based on intermittent Angiotensin II infusions. Using radio telemetry, we demonstrated that the 24-hr BP averages of these mice were similar to controls, indicating BPV without hypertension. Chronic (20-25 days) BPV led to a blunted bradycardic response and cognitive deficits. Two-photon imaging of parenchymal arterioles showed enhanced pressure-evoked constrictions (myogenic response) in BPV mice. Sensory stimulus-evoked dilations (neurovascular coupling) were greater at higher BP levels in control mice, but this pressure-dependence was lost in BPV mice. Our findings support the notion that large BP variations impair vascular function at the neurovascular complex and contribute to cognitive decline.

Research on the Mechanism and Prediction Model of Pressure Drive Recovery in Low-Permeability Oil Reservoirs

China boasts significant reserves of low-permeability oil reservoirs, and the economic and efficient development of these reservoirs plays a crucial role in enhancing oil and gas production. However, the “difficult injection and difficult recovery” issue in low-permeability oil reservoirs is a major challenge. To address this, research is conducted on the mechanism of pressure drive based on the mathematical model of oil-water seepage in low-permeability reservoirs and the model of fracture permeability. The study finds that pressure drive technology, by directly delivering the pressure drive agent deep into the low-permeability reservoir, effectively prevents viscosity loss and adhesion retention of the agent in the near-wellbore area. This technology expands the swept volume, improves oil washing efficiency, replenishes formation energy, and facilitates the gathering and production of scattered remaining oil. For reservoirs with higher permeability, pressure drive yields quick results, and high-pressure water injection can be directly adopted for pressure drive to reduce costs. On the other hand, reservoirs with lower permeability have difficulty in water absorption, and the use of surfactant-based pressure drive can effectively reduce the seepage resistance of the reservoir, enhancing its water absorption capacity and improving development outcomes. Based on the mechanism of pressure drive development, further research is conducted on the production characteristics of pressure drive mines. Addressing the variability in pressure drive effects, big data analysis tools such as SHAP analysis and correlation analysis are employed to evaluate the main controlling factors of pressure drive in both new and old areas. Additionally, non-time series and time series pressure drive production forecasting models are established based on pressure drive data.

Short-Term and Mid-Term Blood Pressure Variability and Long-Term Mortality

Until recently, a focus has been made on exploring the influence of average blood pressure on risk of mortality. We go beyond average blood pressure to also investigate mortality risk with respect to variation in blood pressure over two timescales – short-term variation among multiple measures at one visit, and medium-term variation between the measures at two visits several months apart. We present an application of Bayesian hierarchical modeling to the problem of estimating the effect of blood pressure (BP) variability on all-cause and cardiovascular (CV) mortality. We use data from the Third National Health and Nutrition Examination Survey linked with up to 27 years of mortality follow-up. We find that medium-term systolic BP variability had a very significant predictive value for CV and all-cause mortality, around one-third as large as the well-established impact of mean systolic BP. Medium-term diastolic variability had an additional, though smaller, predictive effect. Short-term variability, on the other hand, had little or no measurable predictive value. The medium-term variability effect persisted when controlling for Framingham risk score.

Sympathetic activity markers in patients with resistant hypertension with renal dysfunction

Aim. To study the informativeness of sympathetic activity markers and perirenal adipose tissue (PRAT) in assessing renal function decline in patients with resistant hypertension (RH).Material and methods. The study included 63 patients with RH of both sexes aged 40-80 years. The main group included 19 patients with chronic kidney disease (CKD). The control group consisted of 44 patients with RH without CKD. All patients were assessed for uric acid, blood lipid profile, beta-adrenergic reactivity of erythrocyte mem­branes, free metanephrine and normetanephrine in plasma and 24-hour urine. The renal function was assessed by the glomerular filtra­tion rate calculated using the CKD-EPI equation. Twenty-four hour blood pressure monitoring was performed on the brachial artery of one arm at intervals of 15 minutes during the day and 30 minutes at night. Kidney size and PRAT were calculated based on the magnetic reso­nance imaging.Results. In both groups of patients, a significant increase in blood normetanephrine and beta-adrenergic reactivity of erythrocyte mem­branes relative to the reference values was shown. Blood and 24-hour urine metanephrine were within the reference intervals. No differences were found between the sympathetic activity indices in the main and control groups. In the main group patients, the PRAT thickness was greater (p=0,013), and the kidney diameter was smaller (p=0,046) than in the control group patients.Conclusion. CKD in RH patients is not accompanied by additional significant changes in sympathetic regulation, assessed by the blood and 24-hour urine catecholamine levels, the degree of beta-adrenergic receptor desensitization and variability of blood pressure. PRAT increase according to magnetic resonance imaging in patients with RH is associated with a decrease in renal filtration function.

Cardiovascular Precision Medicine and Remote Intervention Trial Rationale and Design

Background: It has recently been shown that excessive fluctuation in blood pressure readings for an individual over time is closely associated with poor outcomes, including increased risk of cardiovascular mortality, coronary heart disease and stroke. Fluctuations may be associated with inconsistent adherence to medical recommendations. This new marker of risk has not yet been incorporated into a monitoring and intervention strategy that seeks to reduce cardiovascular risk by identifying patients through an algorithm tied to their electronic health record (EHR). Methods: We describe the methods used in an innovative “proof of concept” trial using CP&amp;R (Cardiovascular Precision Medicine and Remote Intervention). A blood pressure variability index is calculated for clinic patients via an EHR review. Consenting patients with excessive variability are offered a remote intervention aimed at improving adherence to medical recommendations. The outcomes include the ability to identify and engage the identified patients and the effects of the intervention on blood pressure variability using a pre–post comparison design without parallel controls. Conclusions: Our innovative approach uses a recently identified marker based on reviewing and manipulating EHR data tied to a remote intervention. This design reduces patient burden and supports equitable and targeted resource allocation, utilizing an objective criterion for behavioral risk. This study is registered under ClinicalTrials.gov Identifier: NCT05814562.

Remote Monitoring of Sympathovagal Imbalance During Sleep and Its Implications in Cardiovascular Risk Assessment: A Systematic Review.

Nocturnal sympathetic overdrive is an early indicator of cardiovascular (CV) disease, emphasizing the importance of reliable remote patient monitoring (RPM) for autonomic function during sleep. To be effective, RPM systems must be accurate, non-intrusive, and cost-effective. This review evaluates non-invasive technologies, metrics, and algorithms for tracking nocturnal autonomic nervous system (ANS) activity, assessing their CV relevance and feasibility for integration into RPM systems. A systematic search identified 18 relevant studies from an initial pool of 169 publications, with data extracted on study design, population characteristics, technology types, and CV implications. Modalities reviewed include electrodes (e.g., electroencephalography (EEG), electrocardiography (ECG), polysomnography (PSG)), optical sensors (e.g., photoplethysmography (PPG), peripheral arterial tone (PAT)), ballistocardiography (BCG), cameras, radars, and accelerometers. Heart rate variability (HRV) and blood pressure (BP) emerged as the most promising metrics for RPM, offering a comprehensive view of ANS function and vascular health during sleep. While electrodes provide precise HRV data, they remain intrusive, whereas optical sensors such as PPG demonstrate potential for multimodal monitoring, including HRV, SpO2, and estimates of arterial stiffness and BP. Non-intrusive methods like BCG and cameras are promising for heart and respiratory rate estimation, but less suitable for continuous HRV monitoring. In conclusion, HRV and BP are the most viable metrics for RPM, with PPG-based systems offering significant promise for non-intrusive, continuous monitoring of multiple modalities. Further research is needed to enhance accuracy, feasibility, and validation against direct measures of autonomic function, such as microneurography.

Postpartum Blood Pressure Variability and Heart Rate Variability in Preeclampsia.

Preeclampsia is associated with autonomic dysregulation during pregnancy; however, less is known about autonomic function in the first week postpartum after preeclampsia. We retrospectively analyzed data from a prospective cohort of women with and without preeclampsia. Continuous blood pressure and heart rate were measured with finger plethysmography within 7 days postpartum. Frequency-domain blood pressure and heart rate variability (HRV) were calculated using spectral analysis. Time-domain HRV was calculated as the root mean square of successive RR interval differences. We compared results between those with and without preeclampsia, as well as between those with new-onset preeclampsia, chronic hypertension with superimposed preeclampsia, and normotensive participants. A total of 70 postpartum women were enrolled: 20 normotensive, 29 new-onset preeclampsia, and 21 superimposed preeclampsia. Both low- and high-frequency blood pressure variabilities were higher in those with preeclampsia compared with controls (P=0.04 and P=0.02, respectively). This difference was driven by those with new-onset preeclampsia. The preeclampsia group had lower high-frequency HRV (P<0.005), a higher low-/high-frequency ratio of HRV (P<0.005), and lower time-domain HRV (P=0.01); this difference was seen in those with and without chronic hypertension. Postpartum patients with preeclampsia with and without chronic hypertension had lower HRV compared with normotensive postpartum controls. Higher blood pressure variability was observed only in those with nonsuperimposed preeclampsia, suggesting that the autonomic profile of preeclampsia may differ in patients with chronic hypertension.

Incorporating Virtual Reality Agents During a Dichotic Speech Reception Task: Insights From the Heart.

Listening effort is moderated by not only task difficulty, but also success importance. In real communication scenarios, success importance varies based upon the social context. However, in the laboratory, it can be challenging to manipulate social context without compromising experimental control. Outside of hearing sciences, studies have applied virtual reality (VR) to incorporate social context in a controlled and repeatable manner. Several of these studies have demonstrated that social manipulations in VR can reliably elicit changes in cardiovascular measures. Here, we investigated the effect of adding VR agents to a speech reception task, while measuring from the cardiovascular system. Twenty-eight, normally hearing participants undertook a dichotic speech reception task. Sentences in stationary noise were presented dichotically, that is, different sentences presented simultaneously to each ear. Participants were tasked to either repeat one of the sentences (single-sentence condition) or both of the sentences (dual-sentence condition). The task was conducted under two VR conditions: (1) in the presence of agents, who provided sporadic performance feedback and (2) in the presence of nonagent controls, without any feedback given. Alongside task performance, we quantified changes in cardiovascular measures, relative to pretask baselines: heart rate variability, pre-ejection period, heart rate, and blood pressure. After each condition, participants rated their subjective effort, difficulty, performance, and engagement. Performance and the subjective perception of performance were lower, while subjective effort and difficulty were higher, in the dual-sentence condition, compared with the single-sentence condition. Heart rate was the only cardiovascular measure that was sensitive to the experimental manipulations. Contrary to our expectations, heart rate increased in the nonagent control conditions, compared with the agent conditions. An exploratory analysis revealed heart rate fluctuations within a trial: heart rate was higher during the first 6 sec of the trial (reflecting the presentence masking noise and the sentence presentation) in the dual-sentence condition, compared with the single-sentence condition. This study was the first to incorporate VR agents who provided performance feedback during a dichotic speech reception task. Our results suggest that the VR agents did not increase success importance, which could be attributed to a lack of realism of the agents. We also demonstrated that the cardiovascular response to experimental manipulations may differ depending on the data window selected for analysis.

Influence of meteorological factors on intraocular pressure variability using a large-scale cohort

The effects of meteorological conditions on IOP using a large-scale health examination cohort were investigated. There were a total of 811,854 measurements from 126,630 eyes of 63,839 subjects in 9 years from a health checkup cohort followed up annually for age, sex, body height, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), and IOP. The effects of these variables and the meteorological data of daily average temperature (TP), daily average local atmospheric pressure (AP), daily average volumetric humidity (VH), and daily amount of rainfall (RF) on the day of IOP measurement on IOP were investigated. Several variables were significantly associated with IOP, including sex, age, body height, BMI, SBP, DBP, average TP, average AP, average VH, RF, white blood cell count, red blood cell count, hemoglobin, aspartate aminotransferase, alanine aminotransferase, guanosine triphosphate, calcium, and HbA1c. This study indicated a correlation between meteorological factors and IOP. Higher AP and RF were associated with elevated IOP, whereas higher TP and VH were associated with decreased IOP.

Investigating the effects of artificial baroreflex stimulation on pain perception: A comparative study in no-pain and chronic low back pain individuals.

The autonomic nervous system (ANS) and pain exhibit a reciprocal relationship, where acute pain triggers ANS responses, whereas resting ANS activity can influence pain perception. Nociceptive signalling can also be altered by 'top-down' processes occurring in the brain, brainstem and spinal cord, known as 'descending modulation'. By employing the conditioned pain modulation (CPM) paradigm, we previously revealed a connection between reduced low-frequency heart rate variability and CPM. Individuals with chronic pain often experience both ANS dysregulation and impaired CPM. Baroreceptors, which contribute to blood pressure and heart rate variability regulation, may play a significant role in this relationship, although their involvement in pain perception and their functioning in chronic pain have not been sufficiently explored. In the present study, we combined artificial 'baroreceptor stimulation' in both pressure pain and CPM paradigms, seeking to explore the role of baroreceptors in pain perception and descending modulation. In total, 22 individuals with chronic low back pain (CLBP) and 29 individuals with no-pain (NP) took part in the present study. We identified a differential modulation of baroreceptor stimulation on pressure pain between the groups of NP and CLBP participants. Specifically, NP participants perceived less pain in response to baroreflex activation, whereas CLBP participants exhibited increased pain sensitivity. CPM scores were associated with baseline measures of baroreflex sensitivity in both CLBP and NP participants. Our data support the importance of the baroreflex in chronic pain and a possible mechanism of dysregulation involving the interaction between the ANS and descending pain modulation. KEY POINTS: Baroreflex stimulation has different effects on pressure pain in participants with chronic pain compared to matched individuals with no-pain. Baroreceptor activation decreases pain in participants with no-pain but increases pain perception in participants with chronic pain. Baroreflex sensitivity is associated with conditioned pain modulation in both groups of chronic pain and no-pain participants. The reactivity of the baroreflex during autonomic stress demonstrated a positive correlation with Pain Trait scores in participants with chronic back pain.

A noninvasive measurement technique for the initial stiffness of the radial artery

Arterial stiffness carries significant implications for cardiovascular disease. Monitoring changes in arterial stiffness is integral to proactive health management, however, current noninvasive methods of quantifying stiffness in vivo rely primarily on linear tangent stiffness, making the measurements vulnerable to the variability of blood pressure and thereby affecting the accuracy in portraying the health status of the arteries. This study proposed a novel methodology for evaluating arterial stiffness that is unaffected by changes in blood pressure. Ultrasound detection techniques are applied to accurately chronicle changes in radial artery diameters across varied blood pressures. Incorporating blood pressure measurements, the initial diameter at cuff blockade, and vessel diameters at systolic and diastolic pressures enables inverse determination of the unstressed initial radial artery stiffness. This method accurately mirrors the results of in vitro experiments employing porcine blood vessels at physiological pressures. The results underscore the technique's ability to quantify arterial mechanical properties precisely. This study offers a groundbreaking strategy for fostering the early detection of atherosclerosis, and aiding artery health regulation.

Systolic blood pressure variability in late-life predicts cognitive trajectory and risk of Alzheimer's disease.

The relationship of systolic blood pressure variability (SBPV) with Alzheimer's disease (AD) remains controversial. We aimed to explore the roles of SBPV in predicting AD incidence and to test the pathways that mediated the relationship of SBPV with cognitive functions. Longitudinal data across 96 months (T0 to T4) were derived from the Alzheimer's disease Neuroimaging Initiative cohort. SBPV for each participant was calculated based on the four measurements of SBP across 24 months (T0 to T3). At T3, logistic regression models were used to test the SBPV difference between 86 new-onset AD and 743 controls. Linear regression models were used to test the associations of SBPV with cognition and AD imaging endophenotypes for 743 non-demented participants (median age = 77.0, female = 42%). Causal mediation analyses were conducted to explore the effects of imaging endophenotypes in mediating the relationships of SBPV with cognitive function. Finally, Cox proportional hazard model was utilized to explore the association of SBPV with incident risk of AD (T3 to T4, mean follow-up = 3.5 years). Participants with new-onset AD at T3 had significantly higher SBPV compared to their controls (p = 0.018). Higher SBPV was associated with lower scores of cognitive function (p = 0.005 for general cognition, p = 0.029 for memory, and p = 0.016 for executive function), higher cerebral burden of amyloid deposition by AV45 PET (p = 0.044), lower brain metabolism by FDG PET (p = 0.052), and higher burden of white matter hyperintensities (WMH) (p = 0.012). Amyloid pathology, brain metabolism, and WMH partially (ranging from 17.44% to 36.10%) mediated the associations of SBPV with cognition. Higher SBPV was significantly associated with elevated risk of developing AD (hazard ratio = 1.29, 95% confidence interval = 1.07 to 1.57, p = 0.008). These findings supported that maintaining stable SBP in late life helped lower the risk of AD, partially by modulating amyloid pathology, cerebral metabolism, and cerebrovascular health.