Pressure Pulse Wave Research Articles

Antihypertensive treatment with hydrochlorothiazide-hydralazine combination aggravates medial vascular calcification in CKD rats with mineral bone disorder.

Arterial stiffness and medial vascular calcification, leading to isolated systolic blood pressure (BP), are major cardiovascular risk factors in patients with chronic kidney disease (CKD) and mineral bone disorders (MBD). The impact of BP on MBD-induced medial vascular calcification in CKD remains uncertain. We investigated whether BP reduction improves arterial stiffness and medial vascular calcification in a rat model of CKD-MBD. CKD was induced in Wistar rats by subtotal nephrectomy. Then, MBD was generated by a Ca/P-rich diet with calcitriol supplementation to induce medial vascular calcification. Two antihypertensive treatments were evaluated: (1) the angiotensin AT1 receptor antagonist losartan, and (2) the combination of the thiazide diuretic hydrochlorothiazide and the direct vasodilator hydralazine (HCTZ/HY). After 5 weeks, mean BP (MBP), pulse pressure (PP), and pulse wave velocity (PWV) were determined. Vascular calcification was assessed in the thoracic aorta. While MBP was similar in CKD-MBD and control CKD rats, PP and PWV were increased in CKD-MBD rats. The heightened arterial stiffness in CKD-MBD rats was associated with diffused medial calcification along the thoracic aorta. Although both losartan and HCTZ/HY reduced MBP in CKD-MBD rats, losartan did not affect PP and PWV nor medial vascular calcification, whereas HCTZ/HY, unexpectedly, further increased arterial stiffness and medial vascular calcification. In the rat model of CKD-MBD, antihypertensive treatment with losartan did not affect arterial stiffness or medial vascular calcification. However, HCTZ/HY treatment aggravated arterial stiffness and vascular calcification despite a similar reduction of MBP, suggesting a blood pressure-independent mechanism for vascular calcification.

Cuffless Blood Pressure Measurement Using Smartwatches: A Large-Scale Validation Study.

This study aimed to evaluate the performance of cuffless blood pressure (BP) measurement techniques in a large and diverse cohort of participants. We enrolled 3077 participants (aged 18-75, 65.16% women, 35.91% hypertensive participants) and conducted followed-up for approximately 1 month. Electrocardiogram, pulse pressure wave, and multiwavelength photoplethysmogram signals were simultaneously recorded using smartwatches; dual-observer auscultation systolic BP (SBP) and diastolic BP (DBP) reference measurements were also obtained. Pulse transit time, traditional machine learning (TML), and deep learning (DL) models were evaluated with calibration and calibration-free strategy. TML models were developed using ridge regression, support vector machine, adaptive boosting, and random forest; while DL models using convolutional and recurrent neural networks. The best-performing calibration-based model yielded estimation errors of 1.33 ± 6.43 mmHg for DBP and 2.31 ± 9.57 mmHg for SBP in the overall population, with reduced SBP estimation errors in normotensive (1.97 ± 7.85 mmHg) and young (0.24 ± 6.61 mmHg) subpopulations. The best-performing calibration-free model had estimation errors of -0.29 ± 8.78 mmHg for DBP and -0.71 ± 13.04 mmHg for SBP. We conclude that smartwatches are effective for measuring DBP for all participants and SBP for normotensive and younger participants with calibration; performance degrades significantly for heterogeneous populations including older and hypertensive participants. The availability of cuffless BP measurement without calibration is limited in routine settings. Our study provides a large-scale benchmark for emerging investigations on cuffless BP measurement, highlighting the need to explore additional signals or principles to enhance the accuracy in large-scale heterogeneous populations.

Arterial Age and Early Vascular Aging, But Not Chronological Age, Are Associated With Faster Thoracic Aortic Aneurysm Growth.

Background Aneurysm size is an imperfect risk assessment tool for those with thoracic aortic aneurysm (TAA). Assessing arterial age may help TAA risk stratification, as it better reflects aortic health. We sought to evaluate arterial age as a predictor of faster TAA growth, independently of chronological age. Methods and Results We examined 137 patients with TAA. Arterial age was estimated according to validated equations, using patients' blood pressure and carotid-femoral pulse wave velocity. Aneurysm growth was determined prospectively from available imaging studies. Multivariable linear regression assessed the association of chronological age and arterial age with TAA growth, and multivariable logistic regression assessed associations of chronological and arterial age with the presence of accelerated aneurysm growth (defined as growth>median in the sample). Mean±SD chronological and arterial ages were 62.2±11.3 and 54.2±24.5 years, respectively. Mean baseline TAA size and follow-up time were 45.9±4.0 mm and 4.5±1.9 years, respectively. Median (interquartile range) TAA growth was 0.31 (0.14-0.52) mm/year. Older arterial age (ß±SE for 1 year: 0.004±0.001, P<0.0001) was independently associated with faster TAA growth, while chronological age was not (P=0.083). In logistic regression, each 5-year increase in arterial age was associated with a 23% increase in the odds of accelerated TAA growth (95% CI, 1.085-1.394; P=0.001). Conclusions Arterial age is independently associated with accelerated aneurysm expansion, while chronological age is not. Our results highlight that a noninvasive and inexpensive assessment of arterial age can potentially be useful for TAA risk stratification and disease monitoring as compared with the current clinical standard (chronological age).

Experimental Investigation of Gas Transmission Pipeline Blockage Detection Based on Dynamic Pressure Method

The blockage of natural gas pipelines caused by solid deposits such as hydrates is one of the major safety risks to transmission pipeline systems. The key to effective blockage relief or removal is to determine the location and severity of the blockage. In recent years, the pressure pulse wave method has been considered as a practical detection method due to its fast response time, simplicity of operation, and extended detection distance. Nevertheless, the current implementation of this method in pipelines indicates that the accuracy in detecting blockages is very low. To improve the accuracy of the pressure wave blockage detection technique in our experiments, a series of experiments were carried out to detect and locate hydrate blockages in natural gas pipelines based on the pressure wave method using a separate pipeline system of 22 mm diameter and 106 m length. The experimental results show that the accuracy of the blockage location prediction based on the pressure pulse wave method is within 5%. Still, the blockage’s cross-sectional shape can significantly affect the intensity of the reflected wave, with a maximum prediction error of 35%.

Effects of Physical Activity in the High School Curriculum on Cardiovascular Health, Cognitive and Physical Performance.

Cardiovascular health at a young age has implications for preventing cardiovascular disease, and it is associated with improved physical and cognitive performance during the aging process. Sports are well known to prevent cardiovascular disease; however, school-based interventions have mostly been neglected. This cross-sectional study aimed to compare groups of high school students, stratified by the amount of physical activity in their high school curriculum and downtime. Comparisons concerning physical and cognitive performance and arterial stiffness were made. A total of 63 senior-year students were investigated. Arterial stiffness was assessed using the oscillometric technique with ArteriographTM detection. Three-kilometer and pendulum runs were conducted as typical training loads. Cognitive performance was evaluated via the visual and verbal memory and number connection tests. Regarding cognitive skills, extracurricular physical activity improved the number connection test in male participants (p = 0.004). For physical performance, female students with a sports-focused curriculum were faster in the 3 km run (p < 0.001). Concerning arterial stiffness, the measurements yielded a lower mean arterial pressure (p = 0.015) and aortic pulse wave velocity (p = 0.04) in male students with a sports-focused curriculum. In summary, extracurricular physical activity and enrollment in a sports-focused curriculum may be associated with lower cardiovascular risk due to lower arterial stiffness and better physical and cognitive abilities.

Serum uric acid: a futile bystander in endothelial function?

Purpose This study aims to investigate the relationship between serum uric acid levels and endothelial function, oxidative stress, and hemodynamic parameters, and to determine if uric acid levels provide additional insights beyond traditional factors like ageing and hypertension in volunteers with low cardiovascular risk factors. Serum uric acid is known for its antioxidant properties, but it may also contribute to cardiovascular risk. Materials and Methods The study enrolled 40 male participants, divided into three groups based on age and blood pressure status. Group 1 comprised younger participants, group 2 included older individuals without hypertension, and group 3 consisted of older patients with hypertension. The study assessed endothelial function using laser Doppler imaging and measured acetylcholine- and sodium nitroprusside-induced hyperaemia. The heat microcirculatory response was also examined in the presence of L-NAME, an inhibitor of NOS synthase. The study evaluated oxidative stress and arterial stiffness by measuring allantoin, angiotensin II, Homocitrulline/Lysine, and Chloro-Tyrosine/Tyrosine ratios, as well as by performing non-invasive measurements of aortic augmentation indexes and carotid-femoral pulse wave velocity. Results The study found that uric acid levels did not differ significantly among the three groups. Augmentation indexes increased with ageing, but hypertension did not have an additional effect. Blood pressure and carotid-femoral pulse wave velocity differed among the groups, with the lowest values among younger participants and the highest values among older individuals with hypertension. Allantoin and angiotensin II levels did not differ among the groups. However, Homocitrulline/Lysine and Chloro-Tyrosine/Tyrosine ratios were significantly lower in young subjects. Correlation and multivariable analysis showed that uric acid had no effect on any of the studied parameters. Despite a strong association between ageing and systolic blood pressure with impaired endothelial function, oxidative stress, and arterial stiffness, only ageing retained a significant effect in the multivariable analysis. Conclusion In healthy or hypertensive adults with normal renal function, serum uric acid appears to be a futile bystander in endothelial function, oxidative stress, and arterial stiffness, in contrast to ageing, which reduces NO bioavailability. This study suggests that traditional factors such as ageing and hypertension should be the focus of clinical assessment and management of cardiovascular risk, rather than uric acid levels.

Hydraulic circuit for pulse flow simulation in the tissue-mimicking aortic phantom

BACKGROUND: Computed tomographic angiography (CTA) is the gold standard in the diagnosis of most vascular pathologies. The optimal method to improve this technique is the use of anthropomorphic tissue-mimicking phantoms, since CTA is accompanied by radiation exposure and the risk of allergic reactions when using contrast agents. In addition to compliance with the X-ray properties of the vessel, the pulsations occurring in the aorta in vivo must be simulated. A review of existing solutions demonstrates a small number of national developments in this area at a relatively high cost of foreign analogues. Moreover, the lack of reproducible methodology for creating pulse flow simulation devices using available and inexpensive materials is worth noting.&#x0D; AIM: To develop a hydraulic circuit to simulate pulse blood flow in a tissue-mimicking aortic phantom.&#x0D; METHODS: A literature analysis of existing pulse flow simulation devices and tissue-mimicking phantoms of the abdominal aorta was conducted. The medical and technical requirements for the designed device were formulated. The control circuit was developed, the circuit element base was determined, and the hydraulic circuit prototype was assembled. Based on a literature review, a material suitable for reproducing the biomechanical characteristics of arterial tissue was selected. A simplified phantom of the abdominal aortic segment was made. The device model included a simplified abdominal aortic phantom, a control system, a pump, a pressure sensor, a flow meter, and a flow regulator. Initial testing of the developed circuit in the basic signal mode and in the real flow profile simulation mode was performed. The basic signals were periodic rectangular signals reproduced at different frequencies, simulating normal, rapid, and slow heart rate. Using pulse-width modulation, a profile of the pressure pulse wave was obtained.&#x0D; RESULTS: The developed hydraulic circuit allowed successful reproduction of pressure and flow velocity profiles in a tissue-mimicking aortic phantom. Further development of the project will involve fabrication and validation of the circuit (using anthropomorphic versions of the phantom) and simulation of the angiographic study.&#x0D; CONCLUSIONS: The results may be useful for the improvement of CTA techniques and the development of angiosurgical training stands.

Determinants of arterial stiffness in patients with type 2 diabetes mellitus: a cross sectional analysis

In patients with type 2 diabetes mellitus (T2DM) arterial stiffness is associated with increased cardiovascular and total mortality. Little is known about determinants of arterial stiffness in clinical routine. Identification of potential determinants of arterial stiffness will help to address treatment targets for patients in the early state of T2DM. This is a cross-sectional analysis of arterial stiffness in 266 patients in the early stage of T2DM who did not have cardiovascular or renal complications. Parameters of arterial stiffness such as central systolic blood pressure (cSBP), central pulse pressure (cPP) and pulse wave velocity (PWV) were measured with the SphygmoCor System (AtCor Medical). We investigated the influence of parameters of glucose metabolism, lipid status, body constitution, blood pressure (BP) and inflammation on the stiffness parameters using multivariate regression analysis. The study cohort consisted of male and female patients aged 61 ± 8 years with mean diabetes duration of 6.4 ± 5.1 years, mean HbA1c 7.1 ± 0.9%, mean cSBP 121 ± 12 mmHg, mean cPP 44 ± 10 mmHg and mean PWV 8.9 ± 1.8 m/s. Multiple regression analysis identified waist circumference (WC) (beta = 0.411, p = 0.026), LDL-cholesterol (beta = 0.106, p = 0.006), systolic office BP (beta = 0.936, p < 0.001) and diabetes duration (beta = 0.233, p = 0.043) as potential determinants of cSBP. cPP was determined by sex (beta = 0.330, p = 0.008), age (beta = 0.383, p < 0.001), systolic office BP (beta = 0.370, p < 0.001) and diabetes duration (beta = 0.231, p = 0.028) whereas for PWV the following determinants could be identified: age (beta = 0.405, p < 0.001), systolic office BP (beta = 0.421, p < 0.001) and diabetes duration (beta = 0.073, p = 0.038). In addition to the known parameters age, sex and systolic office BP serum LDL-cholesterol, WC and diabetes duration have been identified as determinants of arterial stiffness in patients with T2DM. Treatment of patients in the early stage of T2DM should focus on these clinical parameters to prevent progression of arterial stiffness and as a consequence reduce cardiovascular mortality.Trial registration: The patients included in the analysis participated in one of the following clinical trials NCT02752113 (registered 26.4.2016), NCT02383238 (09.03.2015), NCT02471963 (15.06.2015), NCT01319357 (21.03.2011) (http://www.clinicaltrials.gov).

Human amnion epithelial cells reduces hypertension induced vascular stiffening and cognitive impairment

Introduction: Vascular stiffening and inflammation are hallmarks of hypertension and contribute to the development of cardiovascular disease and cognitive impairment. Current treatments for hypertension may reduce blood pressure but do not target the associated pathological changes and end-organ damage. It is also inconclusive from clinical trials whether anti-hypertensive medication can improve cognitive impairment. Cell therapy has great therapeutic potential as unlike single pharmacological agents, cells can deliver multiple mediators which could more effectively target complex disease mechanisms. Human amnion epithelial cells (AECs) have many properties (eg. anti-inflammatory, anti-fibrotic, and immunologically inert) that make them attractive candidates for a cell-based therapy for vascular and brain pathology. Aim: To test the potential of AECs to treat vascular and brain pathology in angiotensin II-induced hypertension. Methods. Male C57Bl6 mice (8-12 weeks) were administered vehicle (saline; n=35) or angiotensin II (0.7 mg/kg/d, n=37) for 14 d via an osmotic minipump. After minipump implantation, a subset of mice were injected with 10 6 of AECs intravenously. Systolic blood pressure was measured using tail-cuff; pulse wave velocity was measured using ultrasound, inflammation was assessed using flow cytometry and RNA sequencing, markers of fibrosis using quantitative PCR and cognitive function using novel object recognition test. Results: Angiotensin II infusion increased blood pressure and aortic pulse wave velocity (n=6-7, P&lt;0.05). In aorta, angiotensin II promoted accumulation of leukocytes, specifically macrophages and monocytes, which were elevated by ~3-fold compared to vehicle-infused mice (n=9-11, P&lt;0.05). Angiotensin II also increased aortic mRNA expression of collagen type 1 alpha 1 ( Col1a1) by ~4-fold and collagen type 5 alpha 1 ( Col5a1) by ~7-fold compared to vehicle (n=6-8, P&lt;0.05). Co-administration of AECs limited the development of hypertension and aortic stiffening by angiotensin II (185±5 mmHg vs 165±4 mmHg; n=9-11, P&lt;0.05), as well as the aortic infiltration of macrophages and monocytes (n=9-11, P&lt;0.05) and expression of Col1a1 and Col5a1 (n=6-8, P&lt;0.05). Infusion with angiotensin II also impaired memory which was improved by AECs (n=7-9, P&lt;0.05). RNA sequencing revealed that in the brain, angiotensin II increased expression of genes involved in inflammation ( Ptcra, Blk, Bpifb1), fibrosis ( Col6a5) and apoptosis ( Fas) and co-administration of AECs caused downregulation of these genes. Conclusions: Intravenous administration of AECs blunted angiotensin II-induced hypertension, aortic stiffening, inflammation and cognitive impairment in male mice. The beneficial effects of AECs on blood pressure and aortic stiffening could have contributed to the improvement in cognition. This study suggests that AECs or their cellular products could be explored as treatments for vascular and brain pathology during hypertension. La Trobe University Start Up grant This is the full abstract presented at the American Physiology Summit 2023 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.

Structural and functional properties of arteries in COVID-19 survivors

Aim. The study of the structural and functional properties of arteries in patients after a coronavirus disease 2019.Material and methods. The study included 113 people: 45 people who were examined before the start of the COVID-19 pandemic, healthy individuals who had COVID-19 (n=44), 24 patients with hypertension (HTN) in combination with prior COVID-19. In the individuals included in the study, the blood tests were performed, while the carotid arteries were evaluated using high-RF signal technology, applanation tonometry, volume sphygmography, and a test with post-occlusive reactive hyperemia were performed.Results. According to the study of carotid arteries, significant differences were registered between groups of healthy individuals (with and without a history of COVID-19) and HTN patients after COVID-19. According to the applanation tonometry in patients with hypertension and COVID-19 in history, aortic pressure and carotid-femoral pulse wave velocity significantly exceeded those in cohorts of individuals without cardiovascular diseases. According to the results of volume sphygmography in the group of patients after COVID-19, signs of early vascular aging were revealed, and the maximum values of these indicators were recorded in the group of hypertensive patients.Conclusion. The results obtained in the course of this study make it possible to state an increase in the arterial stiffness in people after COVID-19, which can be regarded as a sign of early vascular aging.

Central aortic blood pressure and pulse wave characteristics in patients with decscending thoracic and abdominal aortic aneurysm: features, dynamics, and prognostic significance

Aortic aneurysm (AA) is one of the most formidable cardiovascular diseases, characterized by subtle clinical manifestations and a high risk of complications. Predisposing factors in the development of AA are age, arterial hypertension (HTN), atherosclerosis, and inflammatory aortic diseases. Those are associated with changes in vascular stiffness. HTN causes increased tension in the aortic wall when the pulse wave of blood pressure (BP) rises in patients with AA. Indicators of central BP and vascular stiffness are of particular interest. They present as independent risk factors for cardiovascular events but are poorly studied among patients with AA. The purpose of the review is to summarize the ideas about the relationship of AA with the indicators of vascular stiffness and central hemodynamics in patients with non-operated AA, as well as after endovascular AA repair. Here we discuss the predictive accuracy and applicability of individual markers concerning AA progression and surgical treatment outcomes, as well as unresolved issues and prospects for further research.

Insulin-induced vasoconstriction is prevalent in muscle microvasculature of otherwise healthy persons with type 1 diabetes.

Insulin's microvascular actions and their relationship to insulin's metabolic actions have not been well studied in adults with type 1 diabetes mellitus (T1DM). We compared the metabolic and selected micro- and macrovascular responses to insulin by healthy adult control (n = 16) and subjects with T1DM (n = 15) without clinical microvascular disease. We measured insulin's effect on 1) skeletal muscle microvascular perfusion using contrast-enhanced ultrasound (CEU), 2) arterial stiffness using carotid-femoral pulse-wave velocity (cfPWV) and radial artery pulse wave analysis (PWA), and 3) metabolic insulin sensitivity by the glucose infusion rate (GIR) during a 2-h, 1 mU/min/kg euglycemic-insulin clamp. Subjects with T1DM were metabolically insulin resistant (GIR = 5.2 ± 0.7 vs. 6.6 ± 0.6 mg/min/kg, P < 0.001). Insulin increased muscle microvascular blood volume and flow in control (P < 0.001, for each) but not in subjects with T1DM. Metabolic insulin sensitivity correlated with increases of muscle microvascular perfused volume (P < 0.05). Baseline measures of vascular stiffness did not differ between groups. However, during hyperinsulinemia, cfPWV was greater (P < 0.02) in the T1DM group and the backward pulse wave pressure declined with insulin only in controls (P < 0.03), both indices indicating that insulin-induced vascular relaxation in controls only. Subjects with T1DM have muscle microvascular insulin resistance that may precede clinical microvascular disease.NEW & NOTEWORTHY Using contrast ultrasound and measures of vascular stiffness, we compared vascular and metabolic responses to insulin in patients with type 1 diabetes with age-matched controls. The patients with type 1 diabetes demonstrated both vascular and metabolic insulin resistance with more than half of the patients with diabetes having a paradoxical vasoconstrictive vascular response to insulin.

Influence of Blood Compressibility on Pulse Wave Propagation Properties Based on Elastic Thin-Walled Tube Theory

Pulse wave carries abundant physiological and pathological data about the human body. Understanding the effect of blood compressibility on the transmission qualities of pulse waves is necessary to detect, cure, and prevent cardiovascular problems. In this research, the fluid–solid coupling finite element analysis model of artery system was developed using COMSOL MultiPhysics software. The influence of blood compressibility on pulse wave propagation properties in the brachial artery was investigated using the blood volume compression modulus. Results show that the influence of blood compressibility on pulse wave propagation is relatively weak and may be ignored when evaluating the compressibility of blood and that the volume compression modulus swings 2GPa over and beyond the typical range of the human body. The influence of blood compressibility on the peak value of pressure pulse wave is minor. The attenuation amplitude of the peak value of a pulse wave is bigger for the case with compressible blood than those of case with incompressible blood, and the difference between compressible and incompressible models is less than 1%. But blood compressibility has a clear impact on pulse wave velocity. It is found that the pulse wave velocity is greater than that of blood flow velocity. These findings will be valuable to investigate deeply for evaluating pressure and velocity pulse waves, as well as in providing a waveform-based preliminary diagnosis of symptoms in human body.

On the possibility of non-invasive study of the peripheral mechanisms of autonomous regulation of the human cardiovascular system

The aim of this study was to evaluate the possibility of using the developed method of arterial piezopulsometry for non-invasive study of peculiarities of the functioning of peripheral mechanisms of autonomic regulation of the cardiovascular system in patients of different age and health state. Study emphasizes the importance of determining the variability of the parameters of blood pressure pulse waves as a measure of assessing the participation and role of the components of the neuroendocrine (sympatho-adrenal) efferent link in the formation of a fast and well-regulated response of systemic hemodynamics, using myocytes of the left ventricle of the heart as effectors. This paper discusses the possibility and expediency of personalized use of the arterial piezopulsometry method for pulsometric diagnostics of the functional state and nature of autonomic regulation of the functions of cardiovascular system in patients in order to be able to detect earlier pathological conditions and disorders of peripheral mechanisms that ensure adequate blood supply in humans.

Comparing Remote Speckle Plethysmography and Finger-Clip Photoplethysmography with Non-Invasive Finger Arterial Pressure Pulse Waves, Regarding Morphology and Arrival Time.

The goal was to compare Speckle plethysmography (SPG) and Photoplethysmography (PPG) with non-invasive finger Arterial Pressure (fiAP) regarding Pulse Wave Morphology (PWM) and Pulse Arrival Time (PAT). Healthy volunteers (n = 8) were connected to a Non-Invasive Blood Pressure (NIBP) monitor providing fiAP pulse wave and PPG from a clinical transmission-mode SpO2 finger clip. Biopac recorded 3-lead ECG. A camera placed at a 25 cm distance recorded a video stream (100 fps) of a finger illuminated by a laser diode at 639 nm. A chest belt (Polar) monitored respiration. All signals were recorded simultaneously during episodes of spontaneous breathing and paced breathing. Post-processing was performed in Matlab to obtain SPG and analyze the SPG, PPG and fiAP mean absolute deviations (MADs) on PWM, plus PAT modulation. Across 2599 beats, the average fiAP MAD with PPG was 0.17 (0-1) and with SPG 0.09 (0-1). PAT derived from ECG-fiAP correlated as follows: 0.65 for ECG-SPG and 0.67 for ECG-PPG. Compared to the clinical NIBP monitor fiAP reference, PWM from an experimental camera-derived non-contact reflective-mode SPG setup resembled fiAP significantly better than PPG from a simultaneously recorded clinical transmission-mode finger clip. For PAT values, no significant difference was found between ECG-SPG and ECG-PPG compared to ECG-fiAP.

Oral Arginine Supplementation in Healthy Individuals Performing Regular Resistance Training.

Resistance exercise training is well documented as having cardiovascular benefits, but paradoxically, it seems to increase arterial stiffness, favoring the development of high blood pressure. The present study investigates the potential effects of oral supplementation with arginine in healthy individuals performing exercise resistance training. We studied 70 non-smoking male subjects between the ages of 30 and 45 with normal or mildly increased blood pressure on ambulatory monitoring (for 24 h) and normal blood samples and echocardiography, who performed regular resistance exercise training for at least five years with a minimum of three workouts per week. They were divided into two groups in a random manner: 35 males were placed in the arginine group (AG) that followed a 6-month supplementation of their regular diets with 5 g of oral arginine powder taken before their exercise workout, and the control (non-arginine) group (NAG) consisted of 35 males. All subjects underwent body composition analysis, 24 h blood pressure monitoring and pulse wave analysis at enrollment and at six months. After six months of supplementation, blood pressure values did not change in the NAG, while in the AG, we found a decrease of 5.6 mmHg (p < 0.05) in mean systolic blood pressure and a decrease of 4.5 mmHg (p < 0.05) in diastolic values. There was also a 0.62% increase in muscle mass in the AG vs. the NAG (p < 0.05), while the body fat decreased by 1% (p < 0.05 in AG vs. NAG). Overall, the AG gained twice the amount of muscle mass and lost twice as much body fat as the NAG. No effects on the mean weighted average heart rate were recorded in the subjects. The results suggest that oral supplementation with arginine can improve blood pressure and body composition, potentially counteracting the stress induced by resistance exercise training. Supplementation with arginine can be a suitable adjuvant for these health benefits in individuals undertaking regular resistance training.

PS-BPB01-8: IMPACT OF DIFFERENT DIURETIC TYPES ON ARTERIAL STIFFNESS AND CALCIFICATION IN A RAT MODEL OF CHRONIC KIDNEY DISEASE

Introduction: We reported that antihypertensive therapy with a hydrochlorothiazide (HCTZ)-based regimen aggravates arterial stiffness and vascular calcification in a rat model of chronic kidney disease (CKD) with mineral and bone disorder (MBD). In this study, we investigated whether the aggravation of arterial stiffness and vascular calcification in CKD-MBD rats is induced by HCTZ and whether these abnormalities could also occur with other types of diuretic currently used in clinic. Methods: In rats with renal mass ablation-induced CKD, MBD was generated by a Ca/P-rich diet and calcitriol supplementation. The animals were divided into 4 groups; 1) CKD-MBD control; 2) CKD-MBD + HCTZ (thiazide diuretic, 5 mg/kg/d); 3) CKD-MBD + Chlorthalidone (thiazide-like diuretic, 5 mg/kg/d), and; 4) CKD-MBD + Furosemide (loop diuretics, 10 mg/kg/d). At week 6, hemodynamic parameters including systolic and mean blood pressure (SBP and MBP), pulse pressure (PP) and pulse wave velocity (PWV) were determined. The thoracic aorta was harvested to assess vascular calcification. Results: SBP was reduced by all types of diuretic in CKD-MBD rats. Contrary to chlortalidone nor furosemide, HCTZ treatment led to a reduction of MBP, but an increase in PP and PWV in CKD-MBD rats (p &lt; 0.05). As expected from these hemodynamic changes, medial calcification in the thoracic aorta was significantly greater in CKD-MBD rats treated with HCTZ as compared to all the other groups of rats (p &lt; 0.05). Conclusion: In rats with CKD-MBD, antihypertensive therapy with the thiazide diuretic HCTZ, but not other types of diuretic, exacerbated arterial stiffness and vascular calcification despite a reduction in SBP. The deleterious effect of HCTZ in CKD-MBD rats may have major clinical impact as this diuretic is widely use in patients with CKD that often develop MBD.

PS-C34-8: INFLUENCE OF RISK FACTORS IN THE DEVELOPMENT OF ARTERIAL STIFFNESS IN PATIENTS WITH UNCONTROLLED ARTERIAL HYPERTENSION

Introduction: Arterial stiffness is an unfavorable prognostic marker in patients with arterial hypertension (AH). Early diagnosis of the development of arterial stiffness contributes to the selection of pathogenetic therapy aimed at vascular protection. As noted in the recommendations for hypertension, markers of vascular damage in hypertension are pulse pressure (PP) and pulse wave velocity (PWV) &gt; 10 m/s. However, in the conditions of practical medicine in our republic, there is no possibility of applanation tonometry to assess PWV. Aim: to search for risk factors associated with the early development of arterial stiffness in patients with uncontrolled hypertension. Material and Methods: 133 patients with an average age of 59.13 ± 8.18 years with uncontrolled hypertension, 22.5% of who were smokers. All patients underwent office blood pressure measurements, ECG, duplex scanning of the carotid arteries, applanation tonometry to determine PWV (Sphygmocor, Atcor, Australia) on the segment of the carotid-femoral artery, lipid spectrum, creatinine, and blood serum glucose. Results: Office systolic, diastolic and pulse BP (SBP, DBP and PP) were 164.92 ± 19.0 mm Hg, 99.2 ± 9.08 mm Hg, 65.73 ± 13.67 mm Hg, which corresponded to 2 degrees of arterial hypertension. Central SBP, DBP and PP: 166.96 ± 29.75 mm Hg, 84.8 ± 14.59 mm Hg, PD 81.96 mm Hg. respectively. An increase in PP characterized the development of vascular stiffness in patients with uncontrolled hypertension. At the same time, PWV was 10.8 ± 2.03 m/s; in 60% of patients, PWV exceeded the standard values (&gt; 10 m/s). There was a thickening of the thickness of the intima-media complex (IMC) of the common carotid artery up to 1.11 ± 0.18 mm. The correlation analysis performed showed a direct correlation between PWV and the age of patients (r = 0.383, p = 0.0001), tobacco smoking (r = 0.2, p = 0.004), SBP (r = 0.15, p = 0.046), blood glucose level (r = 0.2, p = 0.008), CMM thickness (r = 0.3, p = 0.0001). Conclusion: The results showed an association of age, SBP, smoking, fasting glucose levels, IMT thickness with the development of arterial stiffness in patients with uncontrolled hypertension. These markers can be determined at the primary health care level and included in the stratification of the risk of vascular damage in patients with uncontrolled hypertension.

Association Between Arterial Stiffness and Measures of Autonomic Dysfunction in People With Chronic Kidney Disease.

Autonomic nervous system (ANS) dysfunction and vascular stiffness increase cardiovascular risk in people with chronic kidney disease (CKD). Chronic elevations in sympathetic activity can lead to increased arterial stiffness; however, the relationship between these variables is unknown in CKD. To explore the association between measures of autonomic function and arterial stiffness in patients with moderate-to-severe CKD. This study was a prespecified secondary analysis of a randomized controlled trial. This included the following measures: 24-hour ambulatory blood pressure (BP), carotid-femoral and carotid-radial pulse wave velocity (PWV), and postexercise heart rate recovery (HRR). We used mixed effect linear regression models with Bayesian information criteria (BIC) to assess the contribution of ANS measurements. Forty-four patients were included in the analysis. Mean carotid-femoral and carotid-radial PWV were 7.12 m/s (95% CI 6.13, 8.12) and 8.51 m/s (7.90, 9.11), respectively. Mean systolic dipping, calculated as percentage change in mean systolic readings from day to night, was 10.0% (95% CI 7.79, 12.18). Systolic dipping was independently associated with carotid-radial PWV, MD -0.09 m/s (95% CI -0.15, -0.02) and had the lowest BIC. Systolic dipping was associated with carotid-radial PWV in people with moderate-to-severe CKD; however, there was no association with carotid-femoral PWV. Systolic dipping may be a feasible surrogate of ANS function, as the association with carotid-radial PWV was consistent with the minimal clinically important difference (MCID). Future studies are needed to define the relationship between ANS function, arterial stiffness, and CV events over time in people with CKD.

Investigation of hydraulic resistance of pulsating flows of viscous fluid in elastic pipe

In recent years, flexible pipes made of synthetic polymer materials are being rapidly introduced into practice. Pulsating currents are important in driving water and other liquids in main pipes. This paper examines the pulsating currents of a viscous incompressible fluid in an elastic pipe. The necessary hydrodynamic parameters will be determined by solving the problem, such as distributions of pressure, velocity, flow rate, propagation velocity of the pressure pulse wave, and their attenuation. For the first time in this article, the decrease in hydraulic resistance in a pulsating flow through pipes due to the elasticity of the wall will be determined. The dependence of the dimensionless value of the pressure pulse wave on the vibrational numberαis studied. The pulse wave speed is compared with the speed of Moens-Korteweg, c∞and significant differences between them are found. The dependence of the reciprocal value of attenuation, related to the wavelength, on the vibrational numberαis also studied; it is shown that the attenuation is free at lower values of the Womersley vibrational parameter, practically equals zero, and at large values of which it asymptotically approaches unity [1-9].