Arterial Pressure Variability Research Articles

The Influence of Various Types of Physical Activity on Blood Pressure. A Literature Review

Blood pressure is a key indicator of cardiovascular health, playing a significant role in the diagnosis, prevention, and treatment of heart and vascular diseases. In recent years, interest in the influence of physical activity on blood pressure has increased among researchers and health-conscious individuals. Among the studies presented, researchers examined the effects of various types of physical activity on blood pressure in individuals with hypertension and the level of hypertension control, as well as other components affecting the overall health of patients, such as blood lipid levels, arterial pressure variability over 24 hours, and BMI. The conclusions of the presented studies seemed to be consistent regarding the positive impact of engaging in physical activity on blood pressure and thus the better well-being of patients.

Analysis of hemodynamics and impedance using bioelectrical impedance analysis in hypovolemic shock-induced swine model

To treat hypovolemic shock, fluid infusion or blood transfusion is essential to address insufficient volume. Much controversy surrounds resuscitation in hypovolemic shock. We aimed to identify the ideal fluid combination for treating hypovolemic shock-induced swine model, analyzing bioelectrical impedance and hemodynamics. Fifteen female three-way crossbred pigs were divided into three different groups. The three resuscitation fluids were (1) balanced crystalloid, (2) balanced crystalloid + 5% dextrose water, and (3) balanced crystalloid + 20% albumin. The experiment was divided into three phases and conducted sequentially: (1) controlled hemorrhage (1 L bleeding, 60 min), (2) resuscitation phase 1 (1 L fluid infusion, 60 min), and (3) resuscitation phase 2 (1 L fluid infusion, 60 min). Bioelectrical impedance analysis was implemented with a segmental multifrequency bioelectrical impedance analyzer. A total of 61 impedance measurements were assessed for each pig at six different frequencies in five segments of the pig. Pulse rate (PR), mean arterial pressure (MAP), stroke volume (SV), and stroke volume variation (SVV) were measured using a minimally invasive hemodynamic monitoring device. The three-dimensional graph showed a curved pattern when infused with 1 L of balanced crystalloid + 1 L of 5% dextrose water and 1.6 L of balanced crystalloid + 400 ml of 20% albumin. The 1M impedance increased in all groups during the controlled hemorrhage, and continuously decreased from fluid infusion to the end of the experiment. Only balanced crystalloid + 20% albumin significantly restored MAP and SV to the same level as the start of the experiment after the end of fluid infusion. There were no significant differences in MAP and SV from the time of recovery to the initial value of 1M impedance to the end of fluid infusion in all groups. The change and the recovery of hemodynamic indices such as MAP and SV coincide with the change and the recovery of 1M impedance. Using balanced crystalloid mixed with 20% albumin in hypovolemic shock-induced swine model may be helpful in securing hemodynamic stability, compared with balanced crystalloid single administration.

EGCG’s effects on Mean Arterial Pressure and Heart Rate Variability and Their Correlations with Metabolic and Hormonal Profiles in Obese Subjects

This study aimed to investigate the effects of epigallocatechin gallate (EGCG), a potent polyphenol found in green tea, on mean arterial pressure (MAP) and heart rate variability (HRV) in obese subjects along with their associations with metabolic factors. We hypothesized that EGCG treatment could significantly reduce MAP and sympathetic tone, represented by decreased low-frequency power (LF) and LF-to-high frequency power (HF) ratio. Furthermore, we expected that systolic blood pressure (SBP), diastolic blood pressure (DBP), and MAP would be positively correlated with obesity parameters, LF, and LF-to-HF ratio. This study is a double-blind, randomized controlled trial. Thai obese subjects with a body mass index (BMI) ≥ 25 kg/m2 (criteria for an Asian population) were randomly allocated into EGCG and placebo groups and received a capsule of 150 mg of EGCG or starch, respectively, twice a day without any dietary restrictions. Clinical and anthropometric data, as well as spontaneous 5-minute HRV measurements in both time and frequency domains, were assessed at baseline (week 0), week 4, and week 8. Additionally, 8-hour fasting blood samples were collected at weeks 0 and 8 to measure metabolic and hormonal levels. EGCG treatment for 8 weeks significantly reduced MAP compared to week 0 and week 4 (P < 0.05 for all). In the EGCG treatment group, there was a significant increase in the LF-to-HF ratio and a nonsignificant decrease in HF at week 8 compared to week 0. LF showed a trend toward increasing in week 8 of EGCG treatment compared to week 4. For correlation analysis at week 0, SBP had significant positive correlations with BMI, percent fat, fat mass, serum leptin and insulin levels, and the homeostatic model assessment for insulin resistance (HOMA-IR) (R = 0.468-0.593, p<0.05 for all) but had negative correlations with the quantitative insulin sensitivity check index (QUICKI) and HDL-cholesterol (R = (-0.437)-(-0.468), P <0.05 for all). DBP was positively correlated with age and HF in normal units (nu) (R = 0.412-0.568, p<0.05 for all), but was negatively correlated with height, HDL-cholesterol, LF in ms (R = (-0.379)-(-0.509), P <0.05 for all). MAP showed significant positive correlations with age, BMI, percent fat, fat mass, serum leptin levels, and HOMA-IR (R = 0.370-0.459, P < 0.05 for all), but had a negative correlation with HDL-cholesterol (R = -0.522, P = 0.004). EGCG treatment over an 8-week duration reduced MAP, a pivotal component of overall blood pressure in obese individuals, and exhibited a significant increase in the LF/HF ratio, tending toward an increase in LF and a non-significant decrease in HF. We postulate that the decrease in MAP may be attributed to EGCG's direct or indirect vasodilatory effects, potentially through the stimulation of nitric oxide production, reduced oxidative stress, and/or decreased levels of kisspeptin, a vasoconstrictive substance, as reported by previous studies. An increase in the LF/HF ratio could reflect a shift toward sympathetic nervous system dominance (LF) and/or a decrease in parasympathetic nervous system activity (HF) indicating a compensatory response to the reduced blood pressure post-vasodilation. HDL cholesterol showed negative correlations with SBP, DBP, and MAP, reflecting its protective benefit against high blood pressure. In summary, 8 weeks of EGCG treatment resulted in a significant decrease in MAP and an increase in the LF/HF ratio, reflecting EGCG’s primary vasodilatory effects and a compensatory increase in sympathetic nervous system activity. The research was funded by the Faculty of Medicine Siriraj Hospital Research Fund ((IO) R015932003, R0159333013 and R016132012). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Anxiety symptom severity is associated with increased arterial blood pressure and arterial blood pressure variability in apparently healthy young adults

Introduction: Lifetime prevalence of anxiety disorders is approximately 30%, and anxiety is associated with an increased susceptibility to develop cardiovascular disease. Anxiety disorders have been linked to hypertension, and autonomic dysfunction has been posited as a contributing factor. However, anxiety symptom severity exists on a continuum, and it is less clear how anxiety severity is associated with blood pressure or beat-to-beat blood pressure variability, a hemodynamic biomarker that reflects dynamic cardiovascular regulatory mechanisms. The objective of this study was to test the hypothesis that self-reported anxiety symptom severity is positively associated with resting blood pressure and beat-to-beat blood pressure variability among healthy young adults without cardiometabolic disease. Methods: Resting beat-to-beat blood pressure (mmHg; finger plethysmography) and anxiety scores from a self-report anxiety symptom questionnaire (Zung Self-Rated Anxiety Scale, ZSRA) were collected in 53 healthy young adults (40 males, 13 females, age = 25 ± 4 yr, BMI = 25 ± 6 kg/m2). Following 10 minutes of quiet rest, signals were recorded over a 10-minute period with participants in a supine position, and the middle 8 minutes were used for analyses. Multiple linear regression was used to examine the independent relations of ZSRA with systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), SAP standard deviation (SAPSD), DAP standard deviation (DAPSD), and MAP standard deviation (MAPSD) while controlling for age and sex. To further understand whether the observed relations between ZSRA and beat-to-beat blood pressure variability were explained by or independent of elevated absolute arterial pressure, partial correlations (rxy,z) were performed for ZSRA versus SAPSD, DAPSD, and MAPSD while partialling out the effect of SAP, DAP, and MAP, respectively. Results: ZSRA was significantly correlated with SAP (β = 0.34, p = 0.015), MAP (β = 0.32, p = 0.023), SAPSD (β = 0.36, p = 0.008), DAPSD (β = 0.35, p = 0.014), and MAPSD (β = 0.37, p = 0.008). When controlling for SAP, DAP, and MAP, ZSRA was independently associated with SAPSD (rxy,z = 0.34, p = 0.016), DAPSD (rxy,z = 0.35, p = 0.012), and MAPSD (rxy,z = 0.40, p = 0.005). Conclusion: Self-reported anxiety symptom severity is associated with increased blood pressure and beat-to-beat blood pressure variability, which indicates an important relationship between anxiety and blood pressure regulation across a continuum of symptom severity. This study is the first to show a relationship between anxiety and beat-to-beat blood pressure variability, independent of absolute mean blood pressure, among healthy young adults devoid of cardiometabolic disease. Our data build upon and align with previous findings that anxiety symptom severity is associated with increased muscle sympathetic nerve activity among healthy young adults and enhances our understanding of the relationship between anxiety and cardiovascular health, even among apparently healthy individuals. Funding provided by a grant from the Injury Prevention Research Center through the CDC (R49 CE003095; NDMJ). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Insulin Treatment Does Not Prevent EARLY Autonomic Cardiovascular and Diastolic Dysfunctions in Streptozotocin-Induced Diabetic Rats.

Recent studies have found increased cardiovascular mortality risk in patients with type 1 diabetes when compared to normoglycemic people, even when they were kept under good glycemic control. However, the mechanisms underlying this condition have yet to be fully understood. Using streptozotocin (STZ)-induced diabetic rats, we evaluated the effects of insulin replacement therapy on cardiac, autonomic, inflammatory, and oxidative stress parameters. Daily treatment with insulin administrated subcutaneously in the STZ-diabetic rats showed a reduction in hyperglycemia (>250 mg/dL) to normalized values. The insulin treatment was effective in preventing alterations in cardiac morphometry and systolic function but had no impact on diastolic function. Also, the treatment was not able to prevent the impairment of baroreflex-tachycardic response and systolic arterial pressure variability (SAP-V). A correlation was found between improvement of these autonomic parameters and higher levels of IL-10 and lower levels of oxidized glutathione. Our findings show that insulin treatment was not able to prevent diastolic, baroreflex, and SAP-V dysfunction, suggesting an outstanding cardiovascular risk, even after obtaining a good glycemic control in STZ-induced diabetic rats. This study shed light on a relatively large population of diabetic patients in need of other therapies to be used in combination with insulin treatment and thus more effectively manage cardiovascular risk.

The relative potential contribution of volume load and vascular mechanisms to hypertension in non-dialysis and dialysis chronic kidney disease patients.

Hypertension is highly prevalent and particularly difficult to treat adequately in patients with chronic kidney disease (CKD). The relative contribution of volume overload and vascular mechanisms to blood pressure measures in CKD and whether these effects differ in non-dialysis compared to dialysis patients is unknown. We determined the potential impact of volume load (stroke volume) and vascular mechanisms (inverse of total arterial compliance (inv TAC) and systemic vascular resistance (SVR)) on mean and brachial and aortic systolic blood pressures in 67 non-dialysis and 48 dialysis chronic kidney disease (CKD) patients. Relationships were determined in confounder adjusted regression models. Stroke volume (p value = 0.003) was more strongly associated with mean arterial pressure than SVR (p value = 0.9) (p value for difference = 0.03). When stroke volume and SVR were entered in the same regression model (model R2 = 0.324), they contributed equally to the variation in mean arterial pressure (p value for difference = 0.5). Stroke volume (p value ≤ 0.002) and inv TAC (p value ≤ 0.001) contributed equally to the variation in systolic pressures (p value for difference ≥ 0.9). When stroke volume and inv TAC were entered in the same regression model (model R2 = 0.752 to 0.765), they contributed equally to the variation in systolic blood pressures (p value for difference = 0.7). Stroke volume, TAC and SVR were similar (p value ≥ 0.5) and associated to the same extent with blood pressure measures in non-dialysis and dialysis CKD patients (p value for difference ≥ 0.1). In receiver operator characteristic curve analysis, elevated systolic blood pressure was determined by stroke volume (p value = 0.005) and inv TAC (p value = 0.03) but not SVR (p value = 0.8). The calculated power of the study was 0.999 based on α = 0.05. The present investigation suggests that both volume load and vascular mechanisms should be considered in the management of hypertension among patients with CKD. The extent and relative potential impact of volume load and vascular mechanisms on blood pressure measures are as large in non-dialysis compared to dialysis CKD patients.

Autonomic Function and Baroreflex Control in COVID-19 Patients Admitted to the Intensive Care Unit.

Background: Autonomic function and baroreflex control might influence the survival rate of coronavirus disease 2019 (COVID-19) patients admitted to the intensive care unit (ICU) compared to respiratory failure patients without COVID-19 (non-COVID-19). This study describes physiological control mechanisms in critically ill COVID-19 patients admitted to the ICU in comparison to non-COVID-19 individuals with the aim of improving stratification of mortality risk. Methods: We evaluated autonomic and baroreflex control markers extracted from heart period (HP) and systolic arterial pressure (SAP) variability acquired at rest in the supine position (REST) and during a modified head-up tilt (MHUT) in 17 COVID-19 patients (age: 63 ± 10 years, 14 men) and 33 non-COVID-19 patients (age: 60 ± 12 years, 23 men) during their ICU stays. Patients were categorized as survivors (SURVs) or non-survivors (non-SURVs). Results: We found that COVID-19 and non-COVID-19 populations exhibited similar vagal and sympathetic control markers; however, non-COVID-19 individuals featured a smaller baroreflex sensitivity and an unexpected reduction in the HP-SAP association during the MHUT compared to the COVID-19 group. Nevertheless, none of the markers of the autonomic and baroreflex functions could distinguish SURVs from non-SURVs in either population. Conclusions: We concluded that COVID-19 patients exhibited a more preserved baroreflex control compared to non-COVID-19 individuals, even though this information is ineffective in stratifying mortality risk.

Temporal and region-specific tau hyperphosphorylation in the medulla and forebrain coincides with development of functional changes in male obese Zucker rats.

Metabolic syndrome (MetS) is associated with development of tauopathies that contribute to cognitive decline. Without functional leptin receptors, male obese Zucker rats (OZRs) develop MetS, and they have increased phosphorylated tau (ptau) with impaired cognitive function. In addition to regulating energy balance, leptin enhances activation of the hippocampus, which is essential for spatial learning and memory. Whether spatial learning and memory are always impaired in OZRs or develop with MetS is unknown. We hypothesized that male OZRs develop MetS traits that promote regional increases in ptau and functional deficits associated with those brain regions. In the medulla and cortex, tau-pSer199,202 and tau-pSer396 were comparable in juvenile (7-8 wk old) lean Zucker rats (LZRs) and OZRs but increased in 18- to 19-wk-old OZRs. Elevated tau-pSer396 was concentrated in the dorsal vagal complex of the medulla, and by this age OZRs had hypertension with increased arterial pressure variability. In the hippocampus, tau-pSer199,202 and tau-pSer396 were still comparable in 18- to 19-wk-old OZRs and LZRs but elevated in 28- to 29-wk-old OZRs, with emergence of deficits in Morris water maze performance. Comparable escape latencies observed during acquisition in 18- to 19-wk-old OZRs and LZRs were increased in 28- to 29-wk-old OZRs, with greater use of nonspatial search strategies. Increased ptau developed with changes in the insulin/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway in the hippocampus and cortex but not medulla, suggesting different underlying mechanisms. These data demonstrate that leptin is not required for spatial learning and memory in male OZRs. Furthermore, early development of MetS-associated autonomic dysfunction by the medulla may be predictive of later hippocampal dysfunction and cognitive impairment.NEW & NOTEWORTHY Male obese Zucker rats (OZRs) lack functional leptin receptors and develop metabolic syndrome (MetS). At 16-19 wk, OZRs are insulin resistant, with increased ptau in dorsal medulla and impaired autonomic regulation of AP. At 28-29 wk OZRs develop increased ptau in hippocampus with deficits in spatial learning and memory. Juvenile OZRs lack elevated ptau and these deficits, demonstrating that leptin is not essential for normal function. Elevated ptau and deficits emerge before the onset of diabetes in insulin-resistant OZRs.

Effects of Daylong Exposure to Indoor Overheating on Thermal and Cardiovascular Strain in Older Adults: A Randomized Crossover Trial.

Health agencies recommend that homes of heat-vulnerable occupants (e.g., older adults) be maintained below 24-28°C to prevent heat-related mortality and morbidity. However, there is limited experimental evidence to support these recommendations. To aid in the development of evidence-based guidance on safe indoor temperatures for temperate continental climates, we evaluated surrogate physiological outcomes linked with heat-related mortality and morbidity in older adults during simulated indoor overheating. Sixteen older adults [six women; median age: 72 y, interquartile range (IQR): 70-73 y; body mass index: ] from the Ottawa, Ontario, Canada, region (warm summer continental climate) completed four randomized, 8-h exposures to conditions experienced indoors during hot weather in continental climates (e.g., Ontario, Canada; 64 participant exposures). Ambient conditions simulated an air-conditioned environment (22°C; control), proposed indoor temperature upper limits (26°C), and temperatures experienced in homes without air-conditioning (31°C and 36°C). Core temperature (rectal) was monitored as the primary outcome; based on previous recommendations, between-condition differences were considered clinically meaningful. Compared with 22°C, core temperature was elevated to a meaningful extent in 31°C [; 95% confidence interval (CI): 0.5, 0.8] and 36°C (; 95% CI: 0.8, 1.1), but not 26°C (, 95% CI: 0.0, 0.3). Increasing ambient temperatures were also associated with elevated heart rate and reduced arterial blood pressure and heart rate variability at rest, as well as progressive impairments in cardiac and blood pressure responses to standing from supine. Core temperature and cardiovascular strain were not appreciably altered following 8-h exposure to 26°C but increased progressively in conditions above this threshold. These data support proposals for the establishment of a 26°C indoor temperature upper limit for protecting vulnerable occupants residing in temperate continental climates from indoor overheating. https://doi.org/10.1289/EHP13159.

Gradients of O-information highlight synergy and redundancy in physiological applications.

The study of high order dependencies in complex systems has recently led to the introduction of statistical synergy, a novel quantity corresponding to a form of emergence in which patterns at large scales are not traceable from lower scales. As a consequence, several works in the last years dealt with the synergy and its counterpart, the redundancy. In particular, the O-information is a signed metric that measures the balance between redundant and synergistic statistical dependencies. In spite of its growing use, this metric does not provide insight about the role played by low-order scales in the formation of high order effects. To fill this gap, the framework for the computation of the O-information has been recently expanded introducing the so-called gradients of this metric, which measure the irreducible contribution of a variable (or a group of variables) to the high order informational circuits of a system. Here, we review the theory behind the O-information and its gradients and present the potential of these concepts in the field of network physiology, showing two new applications relevant to brain functional connectivity probed via functional resonance imaging and physiological interactions among the variability of heart rate, arterial pressure, respiration and cerebral blood flow.

Characteristics of clinical course and comorbidity formation of arterial hypotension in farmer population

The criteria for a significant decrease in arterial pressure is considered to be an element of arterial pressure variability or a certain degree of manifestation. Implementation of various forms of epidemiologic research in order to establish the basis for new approaches to early diagnosis of arterial hypotension, to improve the prognosis, and to achieve high efficiency in prevention has become a necessity and a necessity for farmers in the conditions of Uzbekistan. In the regions of Uzbekistan, there is a great need and necessity to solve the problems of arterial hypotension in this approach. The lack of scientific study of this issue, especially among the large population of Uzbekistan engaged in farming, undoubtedly requires science to fill the “gap” in this direction. Keywords: arterial hypotension, cardiovascular diseases (CVD), chronic heart failure, cardiocomorbidity, non-infectious diseases (NID), arterial pressure variability, independent control of arterial pressure (ABMNQ).

Defining predictors for successful mechanical ventilation weaning, using a data-mining process and artificial intelligence

Mechanical ventilation weaning within intensive care units (ICU) is a difficult process, while crucial when considering its impact on morbidity and mortality. Failed extubation and prolonged mechanical ventilation both carry a significant risk of adverse events. We aimed to determine predictive factors of extubation success using data-mining and artificial intelligence. A prospective physiological and biomedical signal data warehousing project. A 21-beds medical Intensive Care Unit of a University Hospital. Adult patients undergoing weaning from mechanical ventilation. Hemodynamic and respiratory parameters of mechanically ventilated patients were prospectively collected and combined with clinical outcome data. One hundred and eight patients were included, for 135 spontaneous breathing trials (SBT) allowing to identify physiological parameters either measured before or during the trial and considered as predictive for extubation success. The Early-Warning Score Oxygen (EWSO2) enables to discriminate patients deemed to succeed extubation, at 72-h and 7-days. Cut-off values for EWSO2 (AUC = 0.80; Se = 0.75; Sp = 0.76), mean arterial pressure and heart-rate variability parameters were determined. A predictive model for extubation success was established including body-mass index (BMI) on inclusion, occlusion pressure at 0,1 s. (P0.1) and heart-rate analysis parameters (LF/HF) both measured before SBT, and heart rate during SBT (global performance 62%; 83%). The data-mining process enabled to detect independent predictive factors for extubation success and to develop a dynamic predictive model using artificial intelligence. Such predictive tools may help clinicians to better discriminate patients deemed to succeed extubation and thus improve clinical performance.

Association between intraoperative mean arterial pressure variability and postoperative delirium after hip fracture surgery: a retrospective cohort study

BackgroundPostoperative delirium (POD) is a common complication in elderly patients after hip fracture surgery. Our study was to investigate whether intraoperative mean arterial pressure variability (MAPV) was associated with POD in elderly patients after hip fracture surgery.MethodsIn this retrospective cohort study, patients aged 65 years and older undergoing hip fracture surgery were included. The correlation between MAPV and POD was investigated using univariate and multivariate logistic regression. Covariate-related confounding effects were eliminated with propensity score matching (PSM) analysis. Then, a subgroup analysis was conducted to further examine the associations between MAPV and POD.ResultsNine hundred sixty-three patients with a median age of 80 years (IQR: 73–84) were enrolled. POD occurred in 115/963 (11.9%) patients within 7 days after surgery. According to multivariate regression analysis, MAPV > 2.17 was associated with an increased risk of POD (OR: 2.379, 95% CI: 1.496–3.771, P < 0.001). All covariates between the two groups were well balanced after PSM adjustment. A significant correlation between MAPV and POD was found in the PSM analysis (OR: 2.851, 95% CI: 1.710–4.746, P < 0.001).ConclusionsAn increased intraoperative MAPV may be a predictor for POD.

Static autoregulation in humans.

The process by which cerebral blood flow (CBF) remains approximately constant in response to short-term variations in arterial blood pressure (ABP) is known as cerebral autoregulation. This classic view, that it remains constant over a wide range of ABP, has however been challenged by a growing number of studies. To provide an updated understanding of the static cerebral pressure-flow relationship and to characterise the autoregulation curve more rigorously, we conducted a comprehensive literature research. Results were based on 143 studies in healthy individuals aged 18 to 65 years. The mean sensitivities of CBF to changes in ABP were found to be 1.47 ± 0.71%/% for decreased ABP and 0.37 ± 0.38%/% for increased ABP. The significant difference in CBF directional sensitivity suggests that cerebral autoregulation appears to be more effective in buffering increases in ABP than decreases in ABP. Regression analysis of absolute CBF and ABP identified an autoregulatory plateau of approximately 20 mmHg (ABP between 80 and 100 mmHg), which is much smaller than the widely accepted classical view. Age and sex were found to have no effect on autoregulation strength. This data-driven approach provides a quantitative method of analysing static autoregulation that can be easily updated as more experimental data become available.

Abstract 16656: Association of Mean Arterial Pressure Variability With Kidney Function in Living Kidney Donors

Introduction: While mean arterial pressure (MAP) is associated with poor kidney function, the association of MAP variability with kidney function in living kidney donors (LKD) is unknown. We aim to evaluate the association between MAP variability and kidney function post-donation. Hypothesis: Wide MAP variability is associated with worsening kidney function post-donation. Methods: A retrospective cohort study utilizing OPTN/SRTR included adult LKD undergoing donation between 6/1972 and 9/2022. MAP variability is assessed by the average real variability of MAP (ARV-MAP) defined byan average of absolute difference in consecutive MAP at 6, 12, and 24 months post-donation. The risk of ≥35% decrease in post-donation eGFR from pre-donation eGFR among quartiles (Q) for AVR-MAP was examined by multivariable Cox regression. Results: Of 136,984 LKD, mean±SD age was 42±12 years and 61% were female. Mean pre-donation SBP, DBP, and MAP were 122±13, 74±9, and 90±10 mmHg, respectively. Mean post-donation BP at 6, 12, and 24 months were 120±13 / 75±9, 120±13 / 75±9, and 120±12 / 75±9 mmHg, respectively and corresponding mean post-donation MAP were 89.7±9.1, 89.8±9.0, and 90.2±9.0, respectively. Median (IQR) ARV-MAP was 6 (3, 10) mmHg. Mean pre-donation eGFR was 102.1±29.1 ml/min/1.73 m 2 and eGFR at 6-, 12-, and 24-months post-donation were 60.7±42.6, 62.4±43.9, and 64.4±44.9 ml/min/1.73 m 2 , respectively. The incidence rate of the event was 8.21 per 100 person-months. Compared to Q1 of the ARV-MAP, only Q3 had a 3.8% higher risk for declined eGFR (HR Q3 (95%CI) 1.04 (1.00, 1.08)). After adjusting for age, gender, race/ethnicity, U.S. citizenship status, level of education, history of hypertension, pre-donation BMI, pre-donation MAP, eGFR, and post-donation proteinuria, Q2, Q3, and Q4 have a 6.3%, 8.3%, and 6.9% significantly greater risk of the event, respectively (HR Q2 1.06 (1.00, 1.12); HR Q3 1.08 (1.02, 1.14); HR Q4 1.07 (1.01, 1.13)). There is no effect modification of the covariates for the ARV-PP - post-donation eGFR association. Conclusions: The risk for a 35% decline in post-donation kidney function is associated with ARV-MAP. DBP and PP may involve in kidney function after unilateral nephrectomy in LKD who develop post-donation glomerular hyperfiltration.

The degree of engagement of cardiac and sympathetic arms of the baroreflex does not depend on the absolute value and sign of arterial pressure variations

Objective. The percentages of cardiac and sympathetic baroreflex patterns detected via baroreflex sequence (SEQ) technique from spontaneous variability of heart period (HP) and systolic arterial pressure (SAP) and of muscle nerve sympathetic activity (MSNA) burst rate and diastolic arterial pressure (DAP) are utilized to assess the level of the baroreflex engagement. The cardiac baroreflex patterns can be distinguished in those featuring both HP and SAP increases (cSEQ++) and decreases (cSEQ−−), while the sympathetic baroreflex patterns in those featuring a MSNA burst rate decrease and a DAP increase (sSEQ+−) and vice versa (sSEQ−+). The present study aims to assess the modifications of the involvement of the cardiac and sympathetic arms of the baroreflex with age and postural stimulus intensity. Approach. We monitored the percentages of cSEQ++ (%cSEQ++) and cSEQ−− (%cSEQ−−) in 100 healthy subjects (age: 21–70 years, 54 males, 46 females), divided into five sex-balanced groups consisting of 20 subjects in each decade at rest in supine position and during active standing (STAND). We evaluated %cSEQ++, %cSEQ−−, and the percentages of sSEQ+− (%sSEQ+−) and sSEQ−+ (%sSEQ−+) in 12 young healthy subjects (age 23 ± 2 years, 3 females, 9 males) undergoing incremental head-up tilt. Main results. We found that: (i) %cSEQ++ and %cSEQ−− decreased with age and increased with STAND and postural stimulus intensity; (ii) %sSEQ+− and %sSEQ−+ augmented with postural challenge magnitude; (iii) the level of cardiac and sympathetic baroreflex engagement did not depend on either the absolute value of arterial pressure or the direction of its changes. Significance. This study stresses the limited ability of the cardiac and sympathetic arms of the baroreflex in controlling absolute arterial pressure values and the equivalent ability of both positive and negative arterial pressure changes in soliciting them.

Combined effects of whole-body vibration and dynamic squats on cardiovascular and salivary biomarker responses in healthy adults.

This study aimed to investigate the acute effects of combining whole-body vibration with dynamic squats on cardiovascular and salivary bio-marker responses in healthy adults. A randomized crossover design was conducted with 20 healthy adults. Each participant underwent three exercise sessions, with a 2-week washout period between each session. The sessions consisted of: (1) whole-body vibration (VB) at 25 Hz for 2 minutes, with an amplitude of 2 mm, and 2 minutes of rest between sets, for a total of 5 sets; (2) dynamic squats (SQ) performed 15 times within 2 minutes, with a 2-minute rest between sets, for a total of 5 sets; and (3) a combination of whole-body VB and SQ (VB+SQ). The cardiovascular variables and salivary biomarkers related to exercise intensity were assessed. Only the VB+SQ session significantly decreased the unstimulated salivary flow rate, and caused greater changes in heart rate, systolic blood pressure, mean arterial pressure, rate-pressure product, and heart rate variability compared to VB or SQ alone. Moreover, the VB+SQ session significantly increased the salivary total protein concentration from 0.56±0.05 mg/mL (baseline) to 0.74± 0.06 mg/mL (postexercise condition) and the salivary alpha-amylase activity from 33.83±5.56 U/mL (baseline) to 63.63±12.33 U/mL (postexercise condition) (P<0.05). These changes were recovered at 1-hr postexercise condition. Our findings provide information for designing exercise programs that incorporate VB+SQ to enhance hemodynamic and cardiac autonomic responses in healthy adults and for application during rehabilitation periods.

Investigating autonomic nervous system dysfunction among patients with post-COVID condition and prolonged cardiovascular symptoms.

Heart Rate Variability (HRV) and arterial pressure (AP) variability and their responses to head-up tilt test (HUTT) were investigated in Post-COVID-19 syndrome (PCS) patients reporting tachycardia and/or postural hypotension. Besides tachycardia, PCS patients also showed attenuation of the following HRV parameters: RMSSD [square root of the mean of the sum of the squares of differences between adjacent normal-to-normal (NN) intervals] from statistical measures; the power of RR (beat-to-beat interval) spectra at HF (high frequency) from the linear method spectral analysis; occurrence of 2UV (two unlike variation) pattern of RR from the nonlinear method symbolic analysis; and the new family of statistics named sample entropy, when compared to control subjects. Basal AP and LF (low frequency) power of systolic AP were similar between PCS patients and control subjects, while 0 V (zero variation) patterns of AP from the nonlinear method symbolic analysis were exacerbated in PCS patients. Despite tachycardia and a decrease in RMSSD, no parameter of HRV changed during HUTT in PCS patients compared to control subjects. PCS patients reassessed after 6 months showed higher HF power of RR spectra and a higher percentage of 2UV pattern of RR. Moreover, the reassessed PCS patients showed a lower occurrence of 0 V patterns of AP, while the HUTT elicited HR (heart rate) and AP responses identical to control subjects. The HRV and AP variability suggest an autonomic dysfunction with sympathetic predominance in PCS patients. In contrast, the lack of responses of HRV and AP variability indices during HUTT indicates a marked impairment of autonomic control. Of note, the reassessment of PCS patients showed that the noxious effect of COVID-19 on autonomic control tended to fade over time.

Echocardiographic analysis of pulmonary arterial systolic pressure in pulmonary hypertension.

The reliability of pulmonary arterial systolic pressure by transthoracic echocardiography is limited by its variability to define pulmonary hypertension. To know the variability of pulmonary arterial systolic pressure estimated by echocardiography in pulmonary hypertension. Their demographic variables were obtained. From 2016-2020 subjects with pulmonary hypertension were recruited, with pulmonary artery systolic pressure estimated by transthoracic echocardiography and by right heart catheterization. Data were analyzed using the Bland-Altman descriptive statistic and the intraclass correlation coefficient (95% confidence interval). 152 subjects, age 60 ± 12 years, were studied. Body mass index 27.64 ± 4.69 kg/m2. The pulmonary artery systolic pressure estimated by transthoracic echocardiography 58.99 ± 18.62 vs. cardiac catheterization 55.43 ± 16.79 mmHg. Mean difference (bias) -3.6 (29.1, -36.2) and intraclass correlation coefficient 0.717 (0.610, 0.794). Variability is wide, and agreement is substantial for pulmonary artery systolic pressure. It is recommended to estimate only as screening for pulmonary hypertension.

Concurrent exercise training induces additional benefits to hydrochlorothiazide: Evidence for an improvement of autonomic control and oxidative stress in a model of hypertension and postmenopause.

This study aimed to evaluate whether exercise training could contribute to a better modulation of the neurohumoral mechanisms linked to the pathophysiology of arterial hypertension (AH) in postmenopausal hypertensive rats treated with hydrochlorothiazide (HCTZ). Female spontaneously hypertensive rats (SHR) (150-200g, 90 days old) were distributed into 5 hypertensive groups (n = 7-8 rats/group): control (C), ovariectomized (O), ovariectomized treated with HCTZ (OH), ovariectomized submitted to exercise training (OT) and ovariectomized submitted to exercise training and treated with HCTZ (OTH). Ovarian hormone deprivation was performed through bilateral ovariectomy. HCTZ (30mg/kg/day) and concurrent exercise training (3d/wk) were conducted lasted 8 weeks. Arterial pressure (AP) was directly recorded. Cardiac effort was evaluated using the rate-pressure product (RPP = systolic AP x heart rate). Vasopressin V1 receptor antagonist, losartan and hexamethonium were sequentially injected to evaluate the vasopressor systems. Inflammation and oxidative stress were evaluated in cardiac tissue. In addition to the reduction in AP, trained groups improved RPP, AP variability, bradycardic (OT: -1.3 ± 0.4 and OTH: -1.6 ± 0.3 vs. O: -0.6 ± 0.3 bpm/mmHg) and tachycardic responses of baroreflex sensitivity (OT: -2.4 ± 0.8 and OTH: -2.4 ± 0.8 vs. O: -1.3 ± 0.5 bpm/mmHg), NADPH oxidase and IL-10/TNF-α ratio. Hexamethonium injection revealed reduced sympathetic contribution on basal AP in OTH group (OTH: -49.8 ± 12.4 vs. O: -74.6 ± 18.1 mmHg). Furthermore, cardiac sympathovagal balance (LF/HF ratio), IL-10 and antioxidant enzymes were enhanced in OTH group. AP variability and baroreflex sensitivity were correlated with systolic AP, RPP, LF/HF ratio and inflammatory and oxidative stress parameters. The combination of HCTZ plus concurrent exercise training induced additional positive adaptations in cardiovascular autonomic control, inflammation and redox balance in ovariectomized SHR. Therefore, combining exercise and medication may represent a promising strategy for managing classic and remaining cardiovascular risks in AH.