Brachial Artery Flow Research Articles

Acute oral antioxidant consumption does not alter brachial artery flow mediated dilation in young adults independent of exercise training status.

Endothelium-dependent vasodilation can be tested using a variety of shear stress paradigms, some of which may involve the production of reactive oxygen species. The purpose of this study was to compare different methods for assessing endothelial function and their specific involvement of reactive oxygen species and influence of aerobic training status. Twenty-nine (10F) young and healthy participants (VO2max: 34-74mL·kg-1·min-1) consumed either an antioxidant cocktail (AOC; vitamin C, vitamin E, α-lipoic acid) or placebo (PLA) on each of two randomized visits. Endothelial function was measured via three different brachial artery flow-mediated dilation (FMD) tests: reactive hyperemia (RH-FMD: 5min cuff occlusion and release), sustained shear (SS-FMD: 6 min rhythmic handgrip), and progressive sustained shear (P-SS-FMD: three intensities of 3 min of rhythmic handgrip). Baseline artery diameter decreased (all tests: 3.8±0.5 to 3.7±0.6mm, p=0.004), and shear rate stimulus increased (during RH-FMD test, p=0.021; during SS-FMD test, p=0.36; during P-SS-FMD test, p=0.046) following antioxidant consumption. However, there was no difference in FMD following AOC consumption (RH-FMD, PLA: 8.1±2.6%, AOC: 8.2±3.5%, p=0.92; SS-FMD, PLA: 6.9±3.9%, AOC: 7.8±5.2%, p=0.15) or FMD per shear rate slope (P-SS-FMD: PLA: 0.0039±0.0035mm·s-1, AOC: 0.0032±0.0017mm·s-1, p=0.28) and this was not influenced by training status/fitness (all p>0.60). Allometric scaling did not alter these outcomes (all p>0.40). Reactive oxygen species may not be integral to endothelium-dependent vasodilation tested using reactive, sustained, or progressive shear protocols in young males and females, regardless of fitness level.

Effects of PCSK-9 inhibitors on arterial structure and function: preliminary results

Abstract Background One of the latest chapters in the research for new and stronger lipid lowering therapies has led to the development of PCSK9 inhibitors. In addition to the benefit on lipid profile, a limited number of studies have been published showing a possible improvement in vascular function and structure following their administration. Purpose To evaluate the effects of PCSK9 inhibitors on structural (via carotid Intima Media Thickness – IMT) and functional (carotid-femoral Pulse Wave Velocity – cf-PWV - and brachial artery Flow Mediated Dilatation - FMD) arterial properties. Methods Twenty-two dyslipidemic patients with a clinical indication to PSCK9 inhibitors were prospectively recruited at the cardiology rehabilitation of a hospital. Anthropometric, clinical and therapeutic data were recorded. Each patient underwent instrumental examinations to assess cf-PWV, IMT and FMD at T0 (before the start of therapy), T1 (after 6 months) and T2 (after 12 months). Results In the 22 patients who reached 6 months of follow up there was a significant reduction in LDL cholesterol (from 127.8±31.7 to 47.4±29.1 mg/dl, p<0. 0001) while there was no significant difference in arterial parameters (cf-PWV: from 10.5±3.5 to 9.4±2.3 m/s, p=0.092; FMD: from 11.4±8.1 to 9.8±8.3%, p=0.407; IMT: from 775.6±192.8 to 768.7±144.7, microm, p=0.854). Similar results were also obtained in the 12 patients who reached one year of follow-up: LDL from 129.4±29.1 to 48.8±21.9 mg/dl, p<0.0001; cf-PWV from 10.4±3.3 to 10.5±2.9, p=0.874; FMD from 12.0±9.1 to 11.0±5.6%, p=0.930; IMT from 745.1±203.9 to 770.0±127.3 microm, p=0.710. Conclusion Our study confirm the strong LDL reduction with PCSK9 inhibitors that are needed in order to reach the targets set by the ESC 2019 guidelines. In contrast, they do not show a significant effect on arterial function and structure in terms of cf-PWV, FMD and carotid IMT.

Adipokines in rheumatoid arthritis patients suffering glomerulonephritis

Background: Beside their eminent role in metabolic syndrome, white adipose tissue (WAT) derived adipokines might have a distinguished role in autoimmune and rheumatic diseases. In addition, increased level of many adipokines is observed in patients suffering glomerulonephritis. The status of adipokines was not studied in rheumatoid arthritis patients (RA) suffering glomerulonephritis (GN). Objective: To study serum level of adiponectin, leptin, and Visfatin in RA patients suffering GN in a trial to elucidate if they play a role on metabolic or endothelial function. Cases and methods: In this cross-sectional case control observational study, we compared serum level of adiponectin, leptin, and Visfatin in fifty RA patients (group I) in coparison to fifty RA cases suffering chronic GN (group II) and fifty normal control subjects. In addition, we looked for kidney function tests and 24 urine protein (UP), serum calcium, phosphorus, alkaline phosphatase (AP), 25 hydroxy vitamin D (25 OH vit. D), parathyroid hormone (PTH), C-reactive protein (CRP), interleukin 6(IL6), lipid profile, and Homa insulin resistanc (Homa IR). RA cases were further investigated for rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) carotid arteries intima media thickness (IMT), brachial artery flow mediated Dilation (BA-FMD), health assessment questionnaire (HAQ), disease activity score calculator (DASC), simple disease activity index (SDAI), and clinical disease activity index (CDAI). Percutaneous kidney biopsies were obtained in group II patients. Results: Serum adiponectin and Visfatin are significantly higher and serum leptin is significantly lower in Group II compared to group I and the control group (20.3 vs. 18.6 and 12.3, 24,5 vs. 20.9 and 9.8, and 3.6 vs. 4.6 and 7.8 ng/mL for median serum adiponectin, visfatin, and leptin in group II vs group I and control group respectively, P<0.001 in all). Serum level of 25 (OH) vit D is significantly lower, while serum AP, PTH and Homa IR are significantly higher in group I compared to control subjects (18 vs. 37 ng/mL, 140.5 vs, 57 u/L, 63 vs 47.8 ng/mL, and 13.2 vs 4 respectively, P<0.001 in all) whilst there is no significant difference in these parameters between the RA groups. BA-FMD is significantly lower in group II vs group I (3% vs 4%, P=0.02) but there are no significant differences between these two groups in IMT of carotid arteries, HAQ, DASC, SDAI or CDAI. Moreover, there is no difference in any of the studied parameters within patients of group II according to renal histopathology. Conclusion: Studied adipokines have no relation to metabolic or vascular complications of RA. Changes of serum adipokines in GN patients are unrelated to inflammation. This pilot study would stimulate further research looking for the possible role of different adipokines in GN complicating RA.

An ultrasound-guided no incision banding method for the treatment of arteriovenous fistula high-flow in hemodialysis

Objective High-flow vascular access is one of the serious complications in the maturation and subsequent use of arteriovenous fistula (AVF). We adopted a novel surgical approach named no incision limited ligation indwelling needle assisted- revision (NILLINR) to treat high-flow of the hemodialysis vascular access and ascertained the outcomes by regular follow-up visits. Methods This is a retrospective study. 26 hemodialysis patients with symptomatic high-flow access (access flow > 1500 mL/min) were treated with the novel banding method without incision between June 2018 and October 2020. The flow of the brachial artery before and after the restriction was measured by experienced clinicians by using the duplex Doppler ultrasound (DUS). All 26 patients were followed up for up to 1 year. Meanwhile, the brachial artery flow was recorded at 6 months and 1 year after restriction. Results Of all 26 patients included in this study, the mean access flow volume decreased from 2196.2 ± 416.9 mL/min (mean ± SD) to 679.2 ± 67.1 mL/min immediately after the operation. During the follow-up, the volume flow of the brachial artery was still within the restricted range at 6 months (mean ± SD, 720.2 ± 164.7 mL/min) and 1 year (mean ± SD, 713.9 ± 173.8 mL/min) after the operation. Meanwhile, the mean duration of the operation is 8.5 ± 3.3 min, and there is no bleeding or rupture. Conclusion This novel no-incision limited ligation indwelling needle-assisted revision is a safe, effective, and time-saving option to treat high-flow access.

#4066 EARLY EXPERIENCE OF ENDOVASCULAR CREATION OF ARTERIOVENOUS FISTULA IN SOUTHEAST ASIA

Abstract Background and Aims Creation of native arteriovenous fistulae(AVF) has been traditionally through open surgical technique. Endovascular creation of AVF (EndoAVF) has been shown to be an effective alternative to open surgery in Europe and North America. In Asia, EndoAVF creation is a novel technique and we report our early experience of EndoAVF creation in a case series of 18 patients. Method Between Nov 2021 to Aug 2022, ultrasound vein mapping was performed in a total of 39 patients. Eighteen patients were deemed suitable for EndoAVF and proceed for the procedure. EndoAVF creation was attempted by multidisciplinary team comprising of vascular surgeon, interventional radiologists and nephrologists. The patients were prospectively followed-up for at least 6-months. Baseline demographics, vascular characteristics, unassisted maturation, functional patency and freedom from intervention were studied. Results Table 1 shows the baseline demographics of the participants. Twelve patients (67%) were already initiated on hemodialysis via tunneled dialysis catheters during the procedure. EndoAVF was successfully created in 16 (89%) patients. Of which, 13 (72%) were WavelinQ while the remaining 5 (28%) were Ellipsys EndoAVF. The reasons of failures were inability to cannulate artery (n = 1) and vein (n = 1). Minor complications occurred in 6 patients: extravasation in 5 cases and hematoma in 1 patient. The brachial artery flow rates at creation and 1-month post-creation were 558 ± 328 and 583 ± 215 mls/min, respectively. Two participants (11%) underwent interventions to facilitate maturation of the EndoAVF. The median time to maturation was 70 (IQR 49 – 106) days while the median time to first successful 2-needle cannulation was 77 (56 – 127) days. At 6-months, 8 (50%) of EndoAVFs that were successfully created required further intervention to maintain patency, while 1 EndoAVF was abandoned from failure to mature despite intervention Conclusion EndoAVF can be created successfully in a Southeast Asian population. Further studies with more patients and longer follow-up periods are needed to assess long-term outcomes.

EFFECTS OF PCSK-9 INHBITORS ON ARTERIAL STRUCTURE AND FUNCTION: PRELIMINARY RESULTS

Objective: One of the latest chapters in the research for new and stronger lipid lowering therapies has led to the development of PCSK9 inhibitors. In addition to the benefit on lipid profile, a limited number of studies have been published showing a possible improvement in vascular function and structure following their administration. To evaluate the effects of PCSK9 inhibitors on structural (via carotid Intima Media Thickness – IMT) and functional (carotid-femoral Pulse Wave Velocity – cf-PWV - and brachial artery Flow Mediated Dilatation - FMD) arterial properties. Design and method: Twenty-two dyslipidemic patients with a clinical indication to PSCK9 inhibitors were prospectively recruited at the Cardiology Rehabilitation of ASST Grande Ospedale Metropolitano Niguarda Hospital (Milan, Italy). Anthropometric, clinical and therapeutic data were recorded. Each patient underwent instrumental examinations to assess cf-PWV, IMT and FMD at T0 (before the start of therapy), T1 (after 6 months) and T2 (after 12 months). Results: In the 22 patients who reached 6 months of follow up there was a significant reduction in LDL cholesterol (from 127.8±31.7 to 47.4±29.1 mg/dl, p<0. 0001) while there was no significant difference in arterial parameters (cf-PWV: from 10.5±3.5 to 9.4±2.3 m/s, p = 0.092; FMD: from 11.4±8.1 to 9.8±8.3%, p = 0.407; IMT: from 775.6±192.8 to 768.7±144.7, microm, p = 0.854). Similar results were also obtained in the 12 patients who reached one year of follow-up: LDL from 129.4±29.1 to 48.8±21.9 mg/dl, p<0.0001; cf-PWV from 10.4±3.3 to 10.5±2.9, p = 0.874; FMD from 12.0±9.1 to 11.0±5.6%, p = 0.930; IMT from 745.1±203.9 to 770.0±127.3 microm, p = 0.710. Conclusions: Our study confirm the strong LDL reduction with PCSK9 inhibitors that are needed in order to reach the targets set by the ESC 2019 guidelines. In contrast, they do not show a significant effect on arterial function and structure in terms of cf-PWV, FMD and carotid IMT.

EFFECT OF COVID-19 ON BLOOD PRESSURE VARIABILITY IN HYPERTENSIVE PATIENTS

Objective: To investigate the influence of COVID-19 on blood pressure variability in hypertensive patients with known subclinical organ damage (SCOD) previously assessed by evaluation of brachial artery Flow Mediated Dilatation (FMD), carotid artery Intima Media Thickness (IMT), left ventricular mass indexed to BSA (LVMI), E/e` ratio, left atrial volume indexed to BSA (LAVI). Design and method: We assessed 108 hypertensive patients who had SARS-CoV-2 infection in the previously 3 months before evaluation. All subjects included where evaluated for the presence of SCOD in the last 12 months before COVID-19 and underwent a 24-hour noninvasive ABPM on a working day, performing usual daily activities and avoiding heavy physical exercise. BP and heart rate readings were obtained every 15 minutes during daytime and every 30 minutes during nighttime. Subjects recorded a journal of the activities performed and the time of retiring to bed, ABPM recordings being divided into ‘awake’ or ‘asleep’ periods based on diary entries and not on predefined time intervals. BP variability was calculated as the standard deviation (SD) of mean blood pressure. Results: The hypertensive patients with previously known subclinical disease (SCOD+) compared with those without it (SCOD–) had significantly higher systolic and diastolic BP after SARS-CoV-2 infection, and significantly increased variability of both systolic and diastolic BP. Also, they had a significantly reduced decrease of nocturnal systolic BP (table 1). The analysis for each marker of subclinical organ damage indicated that increased systolic BP variability in hypertensive COVID-19 patients was significantly correlated with carotid IMT (r = 0.517, p = 0.001), brachial artery FMD (r = 0.426, p = 0.008), LVMI (r = 0.397, p = 0.009), E/e` ratio (r = 0.543, p = 0.001), left atrial volume indexed to BSA (LAVI) (r = 0.478, p = 0.003) and that diastolic BP variability is significantly correlated with carotid IMT (r = 0.362, p = 0.09), brachial artery FMD (r = 0.491, p = 0.006), LVMI (r = 0.369, p = 0.008), E/e` ratio (r = 0.422, p = 0.005), left atrial volume indexed to BSA (LAVI) (r = 0.407, p = 0.002). Conclusions: Our study indicates that SARS-CoV-2 infection in hypertensive patients induces an increased blood pressure variability which is significantly correlated with the presence of previously diagnosed subclinical disease.

P197 EFFECTS OF PCSK–9 INHBITORS ON ARTERIAL STRUCTURE AND FUNCTION: PRELIMINARY RESULTS

Abstract Background One of the latest chapters in the research for new and stronger lipid lowering therapies has led to the development of PCSK9 inhibitors. In addition to the benefit on lipid profile, a limited number of studies have been published showing a possible improvement in vascular function and structure following their administration. Purpose: To evaluate the effects of PCSK9 inhibitors on structural (via carotid Intima Media Thickness – IMT) and functional (carotid–femoral Pulse Wave Velocity – cf–PWV – and brachial artery Flow Mediated Dilatation – FMD) arterial properties. Methods Twenty–two dyslipidemic patients with a clinical indication to PSCK9 inhibitors were prospectively recruited at the Cardiology Rehabilitation of ASST Grande Ospedale Metropolitano Niguarda Hospital (Milan, Italy). Anthropometric, clinical and therapeutic data were recorded. Each patient underwent instrumental examinations to assess cf–PWV, IMT and FMD at T0 (before the start of therapy), T1 (after 6 months) and T2 (after 12 months). Results In the 22 patients who reached 6 months of follow up there was a significant reduction in LDL cholesterol (from 127.8±31.7 to 47.4±29.1 mg/dl, p<0. 0001) while there was no significant difference in arterial parameters (cf–PWV: from 10.5±3.5 to 9.4±2.3 m/s, p=0.092; FMD: from 11.4±8.1 to 9.8±8.3%, p=0.407; IMT: from 775.6±192.8 to 768.7±144.7, microm, p=0.854). Similar results were also obtained in the 12 patients who reached one year of follow–up: LDL from 129.4±29.1 to 48.8±21.9 mg/dl, p<0.0001; cf–PWV from 10.4±3.3 to 10.5±2.9, p=0.874; FMD from 12.0±9.1 to 11.0±5.6%, p=0.930; IMT from 745.1±203.9 to 770.0±127.3 microm, p=0.710. Conclusion Our study confirm the strong LDL reduction with PCSK9 inhibitors that are needed in order to reach the targets set by the ESC 2019 guidelines. In contrast, they do not show a significant effect on arterial function and structure in terms of cf–PWV, FMD and carotid IMT.

Assessment of early vascular changes in adult females with polycystic ovary syndrome: correlation with insulin resistance

Polycystic ovary syndrome (PCOS) is the commonest endocrine disorder in females in the reproductive period with estimated prevalence of 5% to 18% [1]. It contributes to the mortality and morbidity in patients with PCOS due to the increased risk of different metabolic and cardiovascular (CV) complications [2]. Despite the presence of obesity in 40-60% of cases [3], the disease may occur in non-obese women. The occurrence of metabolic disorders in non-obese PCOS patients, suggests that the syndrome itself may play a role in the development of metabolic and CV co-morbidities [4]. The identification of early stages of atherosclerosis in patients with PCOS might be useful in the development of new strategies to control modifiable CV risk factors [5]. Assessment of vascular endothelial function (ED) as an initial reversible step in atherosclerosis development, may serve as an integral index for CV risk factor burden [6]. In addition, carotid intima media thickness (CIMT) is a helpful marker for atherosclerosis and for the identification of increased risk of CV disease [7]. Our study assessed the early vascular changes in Egyptian women with PCOS both physically and functionally by looking at the CIMT using high resolution Doppler ultrasound and by measuring ED using brachial artery flow–mediated vasodilatation (FMD). Our results indicate that patients with PCOS have significant ED and premature atherosclerosis which is, to a great extent, independent of obesity and IR. This suggests that PCOS patients are at increased risk for premature CVD and may benefit from early detection and management.

Endothelin-1 Contributes to Reduced Endothelial Function in Middle-aged/Older Men with Low Testosterone

Male aging is associated with a general decline in serum testosterone (T) concentrations. Low endogenous T is associated with increased cardiovascular disease risk, and we recently demonstrated accelerated age-related endothelial dysfunction, measured by brachial artery flow mediated dilation (FMD), in middle-aged/older (MA/O) men with low T compared with age-matched men with normal T. Endothlin-1 (ET-1) is a potent vasoconstrictor that is modulated by sex hormones and contributes to age-associated endothelial dysfunction. However, whether ET-1 contributes to reduced FMD in MA/O men with low T has yet to be determined. PURPOSE: to determine if ET-1 contributes to reduced FMD in MA/O men with low T. HYPOTHESIS: we hypothesized that MA/O men with low T would have higher ET-1 concentrations compared with young and MA/O men with normal T. Additionally, we hypothesized that there would be an inverse relation between ET-1 and FMD. METHODS: 60 men were categorized as either young (18-40 years, T: 400-1000 ng/dL) or MA/O (50-75 years) with low (<300ng/dL) or normal (400-1000 ng/dL) serum total T. T was determined from a venous blood draw using a one-step competitive enzyme linked immunosorbent assay. Endothelial function was determined using brachial artery FMD and ET-1 concentrations were determined using radioimmunoassay from a venous blood sample. RESULTS: T concentrations were significantly lower in MA/O men with low T (269±48 ng/dL) compared to young (500±58 ng/dL; p<0.001) or MA/O men with normal T (512±115, ng/dL; p<0.001). There was no difference in T between MA/O men with normal T and young men (p=0.995). MA/O men were similar in age (low T=59±8, normal T=60±6 years; p=0.996) and older than young men (29±4 years; p<0.001 compared to MA/O with both low and normal T). Age-associated reductions in FMD (young=7.3±1.3 vs. MA/O normal T=5.7±2.2%; p=0.019), were exaggerated in MA/O men with low T (4.0±1.7%; p=0.010 vs. MA/O normal T, p<0.001 vs. young). ET-1 concentrations were similar between young and MA/O men with normal T (young= 5.6±0.9 vs. MA/O normal T=6.0±1.4 pg/mL; p=0.768), and higher in MA/O men with low T (7.7±2.8 pg/mL; p=0.002 vs. young, p=0.016 vs. MA/O normal T). There was a moderate inverse association between FMD and ET-1 (r=-0.374, p=0.003). CONCLUSIONS: These data suggest that the greater age-associated endothelial dysfunction in MA/O men with low T may be related to elevations in ET-1. Future studies should examine the effects of low T on endothelin receptors ETA and ETB, as well as factors that could explain the increase in ET-1 in MA/O men with low T. Supported by NIH Grants R01AG049762, U54AG062319, and T32AG000279-16A1 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.

Effects of bioidentical hormone therapy on endothelial function and blood pressure

BACKGROUND: Traditional hormone therapy (HT) is effective for managing menopausal symptoms. Although controversial, HT may also have cardioprotective effects, such as improving endothelial function. However, HT usage plummeted following the Women’s Health Initiative. A popular therapeutic option that has emerged as an alternative is bioidentical hormone therapy (bioHT). Although popular for its claim of being a natural therapy, the effects of bioHT on the cardiovascular system, specifically endothelial function and blood pressure, are not well established in menopausal women. PURPOSE: To test the hypothesis that 5 weeks of bioHT will improve endothelial function and blood pressure in menopausal women. METHODS: Women were recruited from the local community and clinics offering bioHT. Women seeking bioHT completed baseline testing (pre) within seven days of pellet insertion, and again after 5 weeks of treatment (post). Control women were not using any form of hormones, and measured at their convenience 5 weeks apart. Endothelial function was measured using brachial artery flow mediated dilation (FMD). Resting brachial blood pressure was recorded in triplicate in the supine position using an automated sphygmomanometer (Dinamap Dash 2000). Comparisons were made using two-way repeated measures ANOVA. RESULTS: Eleven women completed the study: 4 bioHT (57 ± 5 yrs) and 7 Control (54+4 yrs). Women were well matched for body mass index (bioHT: 25+3 kg/m2; control: 24+3 kg/m2; p=0.75), total cholesterol (bioHT: 213+71mg/dL; control 206+46mg/dL, p=0.84), and fasting plasma glucose (bioHT: 89+6mg/dL; control 90+13mg/dL, p=0.83). After 5 weeks, FMD did not change in bioHT (pre: 4.89% ± .8; post: 5.76% ± 2.2) or control women (pre: 3.73% ± 1.3; post: 4.18% ± 1.7; p>0.10). Resting systolic blood pressure was also not different after 5 weeks in bioHT (pre: 132 ± 20mmHg, post: 126 ± 17mmHg) or control women (pre: 113 ± 5mmHg, post: 110 ± 9mmHg; p>0.05). However, resting diastolic blood pressure tended to decrease in bioHT (pre: 79 ± 12mmHg, post: 72 ± 11mmHg; p=0.08) but not control women (pre: 71 ± 5 mmHg, post: 70 ± 7mmHg; p=0.52). CONCLUSION: These preliminary findings suggest that 5 weeks of bioHT does not negatively impact endothelial function, and may lower resting blood pressure. Additional data are needed to further assess the implications of bioHT on the cardiovascular system. Supported by NIH R01 HL 146558 and P20 GM113125 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.

Sex-specific effects of mild to moderate renal dysfunction on vascular endothelial function and large elastic artery stiffness

BACKGROUND: Cardiovascular disease (CVD) risk is elevated in patients with advanced chronic kidney disease (CKD). Vascular dysfunction, including vascular endothelial dysfunction and large elastic artery stiffening, is a key contributor to increased CVD risk in advanced CKD. Individuals with mild to moderately reduced renal function may also be at increased risk for CVD, but endothelial function and arterial stiffness are not well characterized in this group. Further, women with CKD have lower risk for CVD than men. Whether women are protected from renal dysfunction-related decreases in vascular function is unknown. PURPOSE: We sought to determine: i) whether individuals with mild to moderate renal dysfunction (MRD) have lower endothelial function and greater arterial (aortic) stiffness compared to healthy controls (HC) and ii) if the presence of vascular dysfunction in individuals with MRD is influenced by sex. METHODS & RESULTS: Fifty-nine adults were split into two groups based on renal function. Thirty-two adults (mean±SEM: 66±2 years; 16 women) were identified with MRD, characterized as an estimated glomerular filtration rate (eGFR) of 45-89 (CKD-EPI; 75.0±2.0 mL/min/1.73m2) and/or the presence of microalbuminuria (albumin: creatinine ratio between 30-300 mg/g). Twenty-seven adults (63±2 years; 13 women) were identified as HC with an eGFR >90 (CKD-EPI; 98.7±0.9 mL/min/1.73m2). Subject characteristics known to influence vascular function (e.g., blood pressure, cholesterol, blood glucose, etc.) were not different between groups (all p>0.05). Endothelial function, assessed by brachial artery flow mediated dilation, was not different between groups (MRD: 4.4±0.5%, HC: 4.6±0.5%, p=0.75). Aortic stiffness, assessed via carotid-femoral pulse wave velocity, also was not different (MRD: 950.7±50.6 cm/s, HC: 864.3±33.1 cm/s, p=0.18). When analyzed by sex, men with MRD had lower endothelial function (MRD: 2.8±0.4%, HC: 4.4±0.6%, p=0.04) and tended to have stiffer arteries (MRD: 879.0±42.7 cm/s, HC: 787.7±35.5 cm/s, p=0.11) compared to HC men. In women with MRD, there were no differences in endothelial function (MRD: 5.9±0.8%, HC: 4.8±0.8%, p=0.36) or aortic stiffness (MRD: 1022.3±89.9 cm/s, HC: 953.6±49.4 cm/s, p=0.55) versus HC women. CONCLUSIONS: Men with MRD exhibit vascular dysfunction, while women appear to be protected from MRD-related vascular dysfunction. The lower risk of CVD in women versus men with CKD may, in part, be due to resistance against renal dysfunction-related vascular dysfunction. NIH K01DK115524 to MJR; 5T32DK007135-46 to KOM; K01HL153326 to DHC 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.

Abstract No. 26 Two Year Cumulative Patency Following Creation of Endovascular Arteriovenous Hemodialysis Fistulas with the WavelinQ Device

To assess two-year cumulative patency of endovascular arteriovenous fistulas (endoAVF) created with the WavelinQ device. Patients who had fistulas created at a single center from December 2019 to December 2020 were included in this retrospective study. Data points collected included patient demographics, location of fistula creation, interventions performed and brachial artery flows pre and post creation. Two-year cumulative patency was assessed with Kaplan Meir method and variables that affected patency were examined using the Cox proportional hazards model. Forty-three patients underwent endoAVF creation. (22 females, 21 males). Technical success was 95% (41/43) and in 2 patients the fistula did not mature for dialysis use. For the remaining 39 patients where the endoAVF matured, two-year cumulative patency was 94.8% (SE 3.6%). Mean follow up was 665.7 days with no patients lost to follow-up. There were 15 censored events with two patients undergoing renal transplantation and 13 patients passing away. No examined variables including location of the fistula, brachial flow pre/post creation, and patient demographics significantly impacted patency. Number of interventions per patient year was 0.38 where 8 were maturation procedures (5 surgical vein elevations/transpositions and 3 coil embolizations) and 21 angioplasties for maintenance of fistula patency. 25 were ulnar/ulnar fistulas and 10 were radial/radial fistulas with remaining cases created between the interosseous artery and ulnar or interosseous vein. Mean brachial artery flow pre and post creation was 69 mL/min and 1008 mL/min respectively. One major complication occurred with coil migration to the heart with successful retrieval at the time of the procedure. A high two-year patency following endoAVF creation with the WavelinQ device was observed in this single-center experience.

Cardiovascular profiles associated with white matter hyperintensities in healthy young women.

Women who experience hypertension in pregnancy have increased risk of both chronic hypertension and dementia. High blood pressure is associated with increased evidence of white matter hyperintensities (WMH) in brain imaging. WMH are disruptions of the white matter of the brain that occur with demyelination and axonal degeneration, are associated with vascular disease, occur more frequently in people with hypertension, and are associated with cognitive impairment. We evaluated the relationship between WMH and subclinical cardiovascular function in healthy young nulliparous women and women with a history of early-onset preeclampsia. Sixty-two reproductive-aged women were assessed during the follicular phase of the menstrual cycle after a 3-day sodium/potassium-controlled diet. Half of participants had a history of early-onset preeclampsia, and half were nulliparous. Blood was drawn to assess inflammatory markers. Cardiovascular assessments included tonometric blood pressure monitoring, volume loading to assess vascular compliance, echocardiography to assess cardiac ejection time, brachial pulse wave velocity of the brachial artery, assessing cardiovascular stiffness, and brachial artery flow mediated vasodilation to assess endothelial mediated dilatory response. T2 fluid-attenuated inversion recovery (FLAIR) MRI imaging was obtained. Two raters, blinded to cardiovascular assessments and pregnancy history, reviewed MRI scans for evidence of WMH using the Fazekas rating scale. WMHs were detected in 17 women; 45 had normal white matter structure. Participants with Fazekas score>0 had exaggerated response to volume loading compared to women with a Fazekas score of 0 and longer cardiac ejection times. Fazekas scores >0 had lower brachial flow-mediated vasodilation and increased white blood count compared to those with no evidence of WMH. Women with WMH had reduced cardiovascular compliance, and a trend towards decreased endothelial responsiveness compared to those without WMH. These data demonstrated that the relationship between cardiovascular and brain health was detectable in young, healthy, reproductive-aged women, and may play a role in later development of clinical disease. These findings may help identify women who are at risk for cognitive decline and pathological aging.

Retracted: An Exploratory Study on the Relationship between Brachial Arterial Blood Flow and Cardiac Output.

[This retracts the article DOI: 10.1155/2021/1251199.].

Flow mediated dilatation: searching high and low for a technique

Abstract Funding Acknowledgements Type of funding sources: None. Background Endothelial dysfunction has a central role in atherosclerosis physiology. Flow mediated dilatation (FMD) is a non-invasive method for determining endothelial function. Cuff occlusion of forearm for 5 minutes followed by sudden release cause hyperaemia response with increased flow rate and shear stress in brachial artery. FMD measures the ratio of arterial diameter change mediated by nitric oxide (NO) in response to this increase in shear stress. FMD was first defined in 1992 but has not gained wide clinical utility due to contradictory study results. The main reason for inconsistencies is the lack of standardized definition of FMD technique. We need more studies on different steps of FMD procedure. Purpose The optimal cuff position for FMD measurements is not precisely defined. When brachial arterial flow is disturbed by occlusion, different mediators play role in hyperaemia induced dilatation. Occlusion distal to brachial artery causes mainly NO and endothelium mediated dilatation upstream. Therefore, a forearm occlusion cuff position is proposed. Currently, there is no precise definition of the cuff position in forearm. We compared proximal and distal forearm cuff occlusion positions for FMD measurements. Methods We analysed FMD in fifty healthy volunteers (mean age 31,9 ± 9,5 years; 54 % female). The subjects underwent measurements with two different occlusion positions on the same day. The sequence of occlusion cuff position was determined with randomization. We have waited for an appropriate interval between measurements. We made sure that brachial artery has returned to its basal diameter and flow conditions before second measurement. Flow and diameter measurements were made with strict adherence to predefined timelines after cuff release. Same operator performed and recorded all FMD measurements. Results Measurements of basal diameter (p=0,97) and basal flow (p=0,53) were not different. We used random intercept mixed effects model for comparison of proximal and distal occlusion positions. This enabled interpretation of FMD results with refinement of sequence and basal diameter’s possible effects. The FMD values of proximal forearm occlusion cuff position were 2,2 % higher compared to distal position. (p=0,027) The sequence of occlusion cuff position did not have significant effect on consecutive FMD measurements. (p=0,405). Conclusions We have shown that the forearm occlusion cuff position affects FMD measurements. This effect can be responsible for inter-study differences of FMD. Further research is required for interpretation of this difference in terms of molecular mechanisms and its applicability in clinical practice.

The Influence of Self‐Reported and Actigraphy‐Derived Sleep Quality on Cardiometabolic Health in a Diverse Cohort of Healthy Adults

PurposeInsufficient sleep is associated with adverse cardiometabolic health (CMH) including high blood pressure (BP) and insulin resistance, which increases cardiovascular disease risk. However, there are limited data on insufficient sleep and CMH in healthy adults, particularly in diverse cohorts. Thus, we sought to examine associations between actigraphy‐derived sleep, self‐reported sleep quality, and CMH in healthy adults.Methods99 individuals (50 female, age: 26 ± 12yrs, BMI: 25.5 ± 4.1 kg/m2, resting BP: 108±11/ 65 ± 8 mmHg, mean ± SD) were included in this analysis. We assessed objective sleep quality, including sleep duration and efficiency using wrist‐worn Philips Actiwatch Spectrum PLUS monitors (8.4 ± 2.7 days). Self‐reported sleep was characterized using the Pittsburgh Sleep Quality Index (0 [better] to 21 [worse]) and an average weekly score to the question “how rested do you feel” (0 [better] to 4 [worse]). We combined all four sleep variables to create a multidimensional sleep score (0 [better] to 4 [worse]). Following ≥10‐minutes of supine rest, we assessed oscillometric brachial BP in triplicate. We assessed estimated central BP with pulse wave analysis and arterial stiffness via carotid‐femoral pulse wave velocity (cf‐PWV) with SphygmoCor. We evaluated endothelial function using brachial artery flow mediated dilation (FMD) via ultrasound. We are collected venous blood samples to calculate homeostatic model assessment of insulin resistance (HOMA‐IR) via blood glucose and insulin concentration. We performed stepwise regressions controlling for sex, race, age, and BMI (model 1) and with the addition of individual sleep metrics (model 2) or the multidimensional sleep score (model 3) to determine whether sleep was associated with measures of CMH.ResultsAdding independent sleep variables or composite sleep score did not improve model fit for brachial BP (e.g., systolic BP Model 1: R2= 0.301, p < 0.001, Model 3: R2= 0.262, p<0.001). The addition of sleep variables improved model fit for central BP (e.g., systolic BP Model 1: R2= 0.280, p < 0.001, Model 3: R2= 0.306, p <0.001) and cf‐PWV (Model 1: R2= 0.153 p < 0.001, Model 2: R2= 0.159, p = .014). Furthermore, the multidimensional sleep score was independently associated with central systolic BP (β± SE = ‐2.41 ± 0.961, p = 0.015) and central diastolic BP (β± SE = ‐1.97 ± 0.91, p = 0.035). Finally, the addition of the multidimensional sleep score improved model fit for FMD (Model 1: R2=0.113, p = 0.012, Model 3: R2= 0.132, p = 0.023) and HOMA‐IR (Model 1: R2= 0.229, p<0.001, Model 3: R2= 0.246, p <0.001).ConclusionOur preliminary data indicate that multidimensional sleep is independently associated with central BP and the addition of individual or multidimensional sleep adds upon the predictive value of sex, race age and BMI in predicting CMH in a diverse cohort of healthy adults.

High Sodium Intake Differentially Impacts Brachial Artery Flow Mediated Dilation When Evaluated with Reactive Versus Active Hyperemia

OBJECTIVEThis study sought to determine if a high sodium (HS) intake attenuates upper limb flow mediated dilation in response to reactive (RH‐FMD) and sustained (SS‐FMD) hyperemia, and the role of oxidative stress in this response. Our hypothesis is HS intake will similarly impair upper limb vascular function when assessed as both RH‐FMD and SS‐FMD, and that this dysfunction will be reversed following acute antioxidant consumption.METHODSTen young, salt resistant participants (9 Males, 1 Female) consumed a 7‐day HS (6,900 mg/day) or a 7‐day low sodium (LS: 2,300 mg/day) diet in a randomized order. On the last day of the diet, brachial artery RH‐FMD (evaluated after 5 minutes of cuff occlusion) and SS‐FMD (handgrip exercise) were performed following consumption of placebo (PL) and repeated two hours after the consumption of antioxidants [AO; (1000 mg of vitamin C, 800 IU of vitamin E, and 400 mg of alpha lipoic acid]. Handgrip exercise (HG) was performed in 3‐minute workloads, increasing by 8 kg until failure, at a rate of one contraction per second. RH‐FMD responses were evaluated as percentage change from baseline and SS‐FMD was evaluated as brachial artery shear‐to‐dilation slopes assessed across all HG workloads achieved.RESULTSBetween diets, sodium consumption and excretion were significantly greater in the HS condition (p < 0.05 for both), but mean arterial blood pressure was unchanged (LS 85 ± 5; HS 84 ± 7 mmHg; p = 0.5). RH‐FMD was significantly lower during HS compared to LS (p = 0.01), in the placebo condition but not during the AO condition (p = 0.7), with a significant interaction present (HS+PL: 5.9 ± 3.4; HS+AO: 8.2 ± 2.7; LS+PL: 8.8 ± 4.7; LS+AO: 7.0 ± 2.1 %; p = 0.01) due to a significant increase in the HS+AO condition. A comparison of shear‐dilation slopes during SS‐FMD revealed no differences between sodium interventions (p = 0.3), AO condition (p = 0.1), or any interaction effect (p = 0.7) [HS+PL: 0.0031 ± 0.0013; HS+AO: 0.0026 ± 0.0012; LS+PL: 0.0028 ± 0.0012; LS+AO: 0.0022 ± 0.0010; mm.seconds‐1.kg‐1].CONCLUSIONIndependent of changes in MAP, a HS intake impaired peripheral vascular function when assessed via RH‐FMD, which was restored with AO consumption, potentially implicating elevated oxidative stress as a contributor to this dysfunction. However, SS‐FMD, evaluated via HG exercise, was not altered by a HS intake or AO consumption. In conclusion, 7‐days of a HS intake appears to have disparate effects between the two peripheral vascular function techniques, implicating an inability of HS intake to impact exercise‐induced BA dilation.

On the examination of the viscous response of the brachial artery during flow-mediated dilation

In this study, mechanotransduction is investigated through a physics-based viscoelastic model describing the arterial diameter response during a brachial artery flow mediated dilation (BAFMD) test. The study is a significant extension of two earlier studies by the same group, where only the elastic response was considered. Experimental BAFMD responses were collected from 12 healthy volunteers. The arterial wall's elastic and viscous properties were treated as local variable quantities depending on the wall shear stress (WSS) sensed by mechanotransduction. The dimensionless parameters, arising from the model which serve as a quantitative assessment of the artery's physical state, were adjusted to replicate the experimental response. Among those dimensionless parameters, the viscoelastic ratio, which reflects the relative strength of the viscous response compared to its elastic counterpart, is of special relevance to this paper's main conclusion. Based on the results, it is concluded that the arterial wall's mechanical behavior is predominantly elastic, at least in the strict context of the BAFMD test. Recommendations for potential future research and applications are provided.

A comparison of variability between absolute and relative blood flow restriction pressures.

Recommendations are that blood flow restriction (BFR) be applied relative to arterial occlusion pressure (AOP) to provide a similar stimulus. Compare variability of the change in blood flow, shear rateand discomfort between recommended relative pressures and an absolute pressure. During one visit, brachial arterial blood flow was measured in 91 participants using pulse-wave Doppler ultrasonography. After 5-min seated rest, AOP was measured. Following another 5-min rest, blood flow and discomfort were assessed twice before cuff inflation as controls (C1 and C2), then again with a cuff inflated to each BFR pressure (all measures separated by 1-min). Change scores from C1 to all subsequent measures were calculated (i.e., C2-C1; 40%AOP-C1; 80%AOP-C1; 100 mmHg-C1). Variability of the changes were compared via pairwise modified Pitman-Morgan tests (α = 0.008). Variance (95%CI) of the change for blood flow (ml/min), shear rate (1/s), and discomfort(AU) had similar trends. C2-C1 differed from all conditions (all p < 0.001), 40%AOP-C1 differed from 80% AOP-C1 and 100 mmHg-C1 (all p < 0.001), which did not differ (both p ≥ 0.117). Blood flow: C2-C1 = 469.79 (357.90, 644.07), 40%AOP-C1 = 1263.18 (962.34, 1731.80), 80%AOP-C1 = 1752.90 (1335.42, 2403.18), 100 mmHg-C1 = 1603.18 (1221.36, 2197.92); shear rate: C2-C1 = 6248.24 (4760.10, 8566.15), 40%AOP-C1 = 14 625.30 (11 142.06, 20 050.95), 80%AOP-C1 = 22 064.02 (16 809.13, 30 249.27), 100 mmHg-C1 = 20 778.76 (15 829.98, 28 487.21); discomfort: C2-C1 = 0.07 (0.05, 0.08), 40%AOP-C1 = 2.03 (1.55, 2.78), 80%AOP-C1 = 4.26 (3.25, 5.84), 100 mmHg-C1 = 4.50 (3.43, 6.17). Contrary to previous suggestions, applying relative pressures does not necessarily guarantee a similar stimulus. It seems that higher pressures produce more variable changes even if the external pressure applied is made relative to each individual.