Baseline Brachial Artery Diameter Research Articles

Flow-mediated dilation is modified by exercise training status during childhood and adolescence: preliminary evidence of the youth athlete's artery.

Chronic exercise training is associated with an "athlete's artery" phenotype in young adults and an attenuated age-related decline in endothelium-dependent arterial function. Adolescence is associated with an influx of sex-specific hormones that may exert divergent effects on endothelial function, but whether training adaptations interact with biological maturation to produce a "youth athlete's artery" has not been explored. We investigated the influence of exercise-training status on endothelium-dependent arterial function during childhood and adolescence. Brachial artery flow-mediated dilation (FMD) was assessed in n = 102 exercise-trained (males, n = 25; females, n = 29) and untrained (males, n = 23; females, n = 25) youths, characterized as pre (males, n = 25; females, n = 26)- or post (males, n = 23; females, n = 28)-predicted age at peak height velocity (PHV). Baseline brachial artery diameter was larger in post- compared with pre-PHV youths (P ≤ 0.001), males compared with females (P ≤ 0.001), and trained compared with untrained youths (3.26 ± 0.51 vs. 3.11 ± 0.42 mm; P = 0.041). Brachial FMD was similar in pre- and post-PHV youths (P = 0.298), and males and females (P = 0.946). However, exercise-trained youths demonstrated higher FMD when compared with untrained counterparts (5.3 ± 3.3 vs. 3.0 ± 2.6%; P ≤ 0.001). Furthermore, brachial artery diameter (r2 = 0.142; P = 0.007 vs. r2 = 0.004; P = 0.652) and FMD (r2 = 0.138; P = 0.008 vs. r2 = 0.003; P = 0.706) were positively associated with cardiorespiratory fitness in post-, but not pre-PHV youths, respectively. Collectively, our data indicate that exercise training is associated with brachial artery remodeling and enhanced endothelial function during youth. However, arterial remodeling and endothelium-dependent function are only associated with elevated cardiorespiratory fitness during later stages of adolescence.NEW & NOTEWORTHY We report preliminary evidence of the "youth athlete's artery," characterized by training-related arterial remodeling and elevated endothelium-dependent arterial function in children and adolescents. However, training-related adaptations in brachial artery diameter and flow-mediated dilation (FMD) were associated with cardiorespiratory fitness in adolescents, but not in children. Our findings indicate that endothelium-dependent arterial function is modifiable with chronic exercise training during childhood, but the association between FMD and elevated cardiorespiratory fitness is only apparent during later stages of adolescence.

Exposure to occupational air pollution and vascular endothelial dysfunction in workers of the steel industry in Iran.

Air pollution is recognized as a risk factor for cardiovascular diseases; however, the precise underlying mechanisms remain unclear. This study investigated the impact of occupational air pollution exposure on endothelial function in workers within the steel industry. Specifically, we examined male employees in the coke-making division of the Isfahan Steel Company in Iran, as well as those in administrative roles with no known history of cardiovascular risk. Data on age, body mass index, duration of employment, blood pressure, fasting blood sugar, and lipid profile were collected. To assess endothelial function, flow-mediated dilation (FMD) was measured. The baseline brachial artery diameter was greater (mean difference [95% CI] = 0.068mm [0.008 to 0.128]), while the FMD was lower (mean difference [95% CI] = -0.908 % [-1.740 to -0.075]) in the coke-making group than in the control group. After controlling for potential confounding variables, it was observed that working in the coke-making sector of the industry was associated with lower FMD (F = 3.954, p = .049). These findings indicated that occupational air pollution exposure among workers in the steel industry is linked to impaired endothelium-dependent vasodilation.

Individuals with Post-COVID Conditions Exhibit Delayed Vasodilatory Response following Brachial Artery Occlusion in the Absence of Endothelial Dysfunction and Arterial Stiffness

Background: Post-COVID Conditions (PCC) is a disorder in which individuals who contract the SARS-CoV-2 virus experience prolonged symptoms such as fatigue beyond 4 weeks after initial infection. Preliminary data suggest that individuals who are acutely infected display increased arterial stiffness and endothelial dysfunction, as well as autonomic dysfunction. However, it is not well understood if individuals with PCC continue to experience these dysfunctions beyond acute infection. Therefore, this study aimed to investigate whether vascular and autonomic function are impaired in individuals with PCC compared to individuals without PCC. Methods: Individuals previously infected with the SARS-CoV-2 virus at least 4 weeks prior to participation in the study had vascular and autonomic function assessed at baseline. Individuals experiencing PCC symptoms were classified as symptomatic (SYM, n=12) and individuals without PCC symptoms were classified as asymptomatic (ASYM, n=9). Participants were matched for age (30-55 years) and date since SARS-CoV-2 infection (ranging from 1-12 months). Arterial stiffness (carotid-femoral pulse wave velocity, cfPWV via tonometry), common carotid artery b-stiffness (via ultrasonography and tonometry), and endothelial function (brachial artery flow-mediated dilation, baFMD via ultrasonography) were assessed. Time-to-peak vasodilation (TTP) was assessed from baFMD as the time after cuff release until peak brachial artery dilation. Autonomic function was assessed with spontaneous cardiovagal baroreflex sensitivity (BRS) via sequence technique. Results: At baseline, there were no differences between groups in cfPWV (SYM: 6.2 ± 0.7 m/s, ASYM: 6.3 ± 1.1 m/s; p=0.90), baFMD (SYM: 7.3 ± 6.1%, ASYM: 7.7 ± 5.6%; p=0.87), brachial artery baseline diameter (SYM: 3.4 ± 0.6 mm, ASYM: 3.2 ± 0.4 mm; p=0.37) and common carotid b-stiffness index (SYM: 9.2 ± 2.1U, ASYM: 8.2 ± 2.5U; p=0.360). Despite no differences in baFMD% between groups, the SYM group had a significantly higher baseline baFMD TTP compared with the ASYM group (SYM: 61.6 ± 23.1 s, ASYM: 36.8 ± 14.3 s; p=0.010). There were no significant differences in cardiovagal BRS (SYM: 10.9 ± 6.8 ms/mmHg, ASYM: 11.8 ± 2.6 ms/mmHg; p=0.80). Conclusions: While arterial stiffness, endothelial function and baroreflex function did not differ between groups, individuals with PCC did present with delayed peak brachial artery vasodilation in response to shear stress. These data suggest any possible effects on vascular and autonomic function from acute SARS-CoV2 infection appear to be resolved beyond 4 weeks in those who experience prolonged symptoms. However, the delayed vasodilatory response may indicate some level endothelial dysfunction that persists in individuals with PCC. Funded by: Russell B. Day and Florence D. Day Chair in Liberal Arts and Sciences fund. 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.

Abstract 3139: Evidence Of Vascular Endothelial Dysfunction In Habitual Hookah (i.e., Waterpipe) Users: Insights For Cardiovascular Disease Risk

Introduction: Flavored hookah tobacco smoking among young adults continues to be a public health concern. While short-term exposure to flavored hookah tobacco smoking impairs vascular function, data on the long-term impact of habitual use are not clearly delineated. Research Question: Is habitual flavored hookah tobacco smoking associated with vascular endothelial dysfunction in young healthy adults? Goals: Investigate the impact of regular flavored hookah tobacco smoking on vascular endothelial function, as compared to regular cigarette smoking and never tobacco use, in young healthy adults. Methods: We assessed brachial artery flow-mediated dilation (FMD)—a well-established index of vascular endothelial function—in 22 exclusive chronic hookah smokers (25±1 years of age, 23% women; mean±SE), who reported smoking flavored hookah tobacco on average two times per week for 9±1 years, 22 exclusive cigarette smokers who reported 4±1 pack years, and 23 non-smokers. FMD and vascular endothelium-independent nitroglycerin-mediated vasodilation was assessed using high resolution ultrasound. Results: Whereas baseline brachial artery diameter was comparable between groups ( P =ns), brachial artery FMD was significantly lower in habitual hookah users and cigarette users as compared to never smokers (cigarette smokers: 5.22±0.42; hookah smokers: 6.43±0.50; non-smokers: 9.80±0.83; P <0.05). Endothelium-independent dilation of the brachial artery in response to sublingual nitroglycerin did not significantly differ between groups. Conclusions: Despite claims of safety advertised by the growing hookah tobacco industry, our findings provide evidence that, as compared to non-tobacco users, young and apparently healthy adults who regularly smoke flavored hookah tobacco exhibit reduced vascular endothelial function. These results suggest that flavored hookah tobacco smoking is not without harm and has potential harmful vascular effects, associated with increased cardiovascular disease risk.

Endogenous Acetylcholine Contributes to Flow-Mediated Dilation in Humans

Background & Objective. Flow-mediated dilation (FMD) is a crucial function of the vascular endothelium wherein intraluminal shear stress stimulates endothelium-dependent vasodilation mediated primarily by nitric oxide. Brachial artery FMD (baFMD) is widely evaluated in clinical research as an index of endothelial function, and impaired baFMD is an independent predictor of cardiovascular risk. Despite the physiological and clinical relevance of FMD, the mechanisms by which shear stress is transduced to endothelium-dependent vasodilation (i.e., upstream of nitric oxide production) remain unclear. baFMD corresponds closely with sensitivity to the endothelium-dependent vasodilator acetylcholine (ACh), and preclinical models suggest ACh is released from endothelial cells in response to shear stress. Therefore, the present study tested the hypothesis that activation of muscarinic ACh receptors facilitates baFMD in humans. Methods. baFMD was evaluated using Doppler ultrasound in healthy participants (n=11; 5F/6M; 23±2 y; means ± SE) under control conditions and following local inhibition of muscarinic ACh receptors via intra-arterial atropine infused proximal to the measurement site. baFMD was assessed in response to transient and sustained shear stimuli in separate trials: 1) reactive hyperemia following 5 min of arterial cuff occlusion (RH-FMD) and 2) steady-state rhythmic handgrip exercise at graded intensities (10, 15, 20, & 25% maximal voluntary contraction, MVC) to produce step increases in shear rate (EX-FMD). Blockade effcacy was confirmed via a dose-response to intra-arterial ACh infusion pre and post atropine. Results. Baseline brachial artery diameter and forearm blood flow were similar in all trials (all P>0.05). Atropine reduced peak brachial artery dilation following cuff release (RH-FMD, Δ diameter, atropine: 4.6±0.8 vs. control: 6.5±0.8%, P=0.04) and increased the shear stimulus (shear rate area under the curve, SRAUC: atropine, 29±3 vs. control: 21±3 s−1×103, P=0.01) such that the percent change in brachial diameter was diminished by 35±16% when normalized to SRAUC (baFMD:SRAUC ratio, atropine: 1.7±0.3 vs. control: 3.9±1.0, P=0.02). Similarly, in the EX-FMD trial, atropine reduced brachial artery diameter at all exercise intensities (25% MVC, percent change in diameter: atropine, 10.8±1.4 vs. control, 15.5±1.7%, P=0.04) despite a greater shear stimulus (shear rate: atropine, 10.9±1.1 vs. control, 9.3±0.9 s−1×102, P=0.01). Thus, atropine reduced the slope describing the relationship between brachial artery vasodilation (percent change) and the change in shear rate by 38±8% across all exercise intensities (slope, atropine: 1.3±0.1 vs. control: 2.4±0.4% Δ×s×10−2, P=0.007). As expected, atropine reduced brachial artery vasodilation in response to upstream infusion of ACh (1.5 μg ACh/dl forearm volume/min, Δ diameter, atropine: 2±1 vs. control: 23±4%, P=0.001). Conclusions. The results suggest endogenous ACh facilitates baFMD in response to both transient and sustained shear stimuli, which highlights a novel physiological role of endogenous ACh in vascular regulation in humans and provides insight regarding the basic mechanisms of flow-mediated vasodilation. NIH R01 HL119337 and F31 HL142240. 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.

(134) Early Impact of Androgen Deprivation Therapy on Endothelial Function and Metabolic Parameters in Prostate Cancer Patients: A Prospective Study

Abstract Introduction Androgen deprivation therapy (ADT) is considered one of the mainstays in the treatment of prostate cancer. ADT slows cancer progression, alleviates cancer-related symptoms, and is associated with survival gains. Despite these proven benefits, this treatment is related to several side effects, such as increased cardiovascular risk, changes in body composition and various metabolic changes. Although the well-established association between circulating testosterone level and endothelial integrity, the direct effects of ADT on endothelial function remain controversial. Objective This study aimed to investigate the impact of ADT on endothelial function, through the analysis of vascular parameters of the brachial artery and measurement of serum inflammatory markers. It was also our aim to evaluate the early impact of ADT on body composition and metabolic parameters. Methods We prospectively evaluated men with moderate to high-risk prostate cancer treated with ADT from January to December 2022 at our institution. Smokers and those who quit smoking less than five years ago, decompensated diabetics (glycated hemoglobin > 9%) and those who had already had a cardiovascular event were excluded. High-resolution B-mode ultrasound was used to assess vascular diameter and endothelium-dependent flow-mediated vasodilation (FMD) of the brachial artery. Our metabolic and inflammatory profile included measurement of serum total cholesterol and fractions, triglycerides, fasting glucose, glycated hemoglobin, basal insulin, C-reactive protein and assessment of body fat distribution through bioelectrical impedance. Subjects were evaluated at baseline and 3 months after starting ADT with goserelin acetate 10.80 mg. Results A total of 32 men were included. The mean age was 69 years and the prevalence of diabetes was 31.25%. FMD demonstrated a worsening trend after ADT, which did not reach statistical significance after 3 months (mean 3.39 ± 6.83 vs 1.16 ± 7.65; p = 0.14) (figure 1). Baseline brachial artery diameter also showed a tendency to worsen with ADT compared to baseline (0.44 ± 0.06 vs 0.42 ± 0.06; p = 0.06). With regard to the metabolic profile, ADT significantly increased insulin resistance: fasting glucose (mean 104.10 ± 18.96 vs 110.60 ± 25.29; p = 0.01), fasting insulin levels (mean 13.05 ± 8.76 vs 16.82 ± 11.36; p = 0.003), glycated hemoglobin (mean 5.89% ± 0.46 vs 6.15% ± 0.67; p = 0.008) and homeostatic model assessment insulin resistance (mean 3.47 ± 2.55 vs 5.05 ± 4.50; p = 0.005) increased significantly after 3 months. Triglycerides concentrations (mean 142.30 ± 69.66 vs 165.50 ± 93.04; p = 0.03) were higher after 3 months of ADT. Abdominal circumference (mean 98.66 ± 10.16 vs 99.76 ± 9.39; p = 0.02) and body mass index (mean 27.46 ± 4.06 vs 27.76 ± 3.89; p = 0.02) also increased after ADT. Conclusions Although not statistically significant, the present study demonstrated a trend towards a decrease in brachial artery FMD. We also observed an important and surprisingly early worsening of the metabolic profile with ADT, especially increased insulin resistance and dyslipidemia, which represent well-established risk factors for cardiovascular events. Disclosure No.

(297) Evaluation of Endothelial Function and Metabolic Profile in Patients with Prostate Cancer Undergoing Androgen Deprivation Therapy

Abstract Introduction Androgen deprivation therapy (ADT) has been the cornerstone of prostate cancer treatment. ADT delays cancer progression, alleviates cancer-related symptoms, and is associated with survival gains. Despite these established benefits, the therapy comes with known side effects, such as increased cardiovascular adverse events and metabolic changes. Despite the well-established association between the level of circulating testosterone and endothelial integrity, the direct effects of ADT on endothelial function remain controversial. Objective The aim of the present study was to investigate the impact of ADT on endothelial function, through the analysis of vascular parameters of the brachial artery, and the measurement of serum inflammatory markers. It was also our goal to evaluate early impact of ADT on anthropometric and metabolic parameters Methods We prospectively evaluated men with moderate to high-risk prostate cancer treated with ADT from January to July 2022 at our institution. Patients with decompensated diabetes mellitus (HbA1c >9%), active smokers or smokers who have ceased for less than 5 years and those with confirmed diagnosis of peripheral artery disease, coronary artery disease, angina, congestive heart failure, myocardial infarction, coronary revascularization or stroke, were excluded. Brachial artery assessment included vascular diameter and flow-mediated (endothelium-dependent) vasodilation (FMD) using high-resolution B-mode ultrasound. Our metabolic and inflammatory profile included serum measurement of total cholesterol and fractions, triglycerides, fasting glucose, glycated hemoglobin, basal insulin, C-reactive protein, and bioimpedance assessment of body fat distribution. All measurements were performed at baseline and after 3 months of ADT initiation with goserelin acetate 10.80mg. Results A total of 14 men with mean age of 67.9 ± 6.9 years were included. The prevalence of diabetes in the present cohort was 21.4%. FMD demonstrated a slight increase following ADT, which did not reach statistical significance after 3 months (median 2.2% vs. 5.0%; p = 0.8224 – Figure 1). Baseline brachial artery diameter significantly decreased with ADT compared to baseline (median diameter 0.43cm vs 0.40cm; p = 0.006). With regard to the metabolic profile, ADT significantly increased insulin resistance: fasting insulin levels (mean 9.67 ± 6.09 vs 13.19 ± 7.47; p = 0.002), glycated hemoglobin (mean 5.79% ± 0.47 vs 6.22% ± 0.75; p = 0.009) and homeostatic model assessment insulin resistance increased significantly after 3 months (p = 0.006). Low-density lipoprotein cholesterol (mean 112.00 ± 27.35 vs 128.90 ± 29.00; p = 0.01) and triglycerides (mean 145.40 ± 78.52 vs 168.20 ± 105.80; p = 0.03) concentrations were higher after 3 months of ADT. No significant differences were found in body fat distribution. Conclusions Although the present study has not demonstrated a significant change in brachial artery FMD, we verified an important and surprisingly early worsening of the metabolic profile with ADT, especially increased insulin resistance and dyslipidemia, which represent well-established risk factors for cardiovascular events. Disclosure No

Macrovascular Function Assessed By Flow-mediated Dilation Does Not Change Across Menstrual Cycle Regardless Of Race

A race disparity in vascular function has been identified between premenopausal black women and white women during the low hormone phase of the menstrual cycle. However, to the best of our knowledge, no previous study assessing macrovascular function across the menstrual cycle has reported the racial characteristics of their participants. PURPOSE: To assess macrovascular function across the menstrual cycle in a racially diverse group of young, normotensive, non-obese, naturally cycling women using brachial artery flow-mediated dilation (FMD). METHODS: Participants self-identified as either non-Hispanic white (WHW), non-Hispanic black (BLW), or Hispanic (HW). FMD was performed during three menstrual phases: early follicular (EF; first 1-5 days of menstruation), ovulation (OV; determined by an at-home ovulation test, 1-3 days surrounding the luteinizing hormone surge), and mid-luteal (ML; 7-to-10 days post ovulation, depending on cycle length). Brachial artery diameter and blood velocity were assessed using Doppler ultrasound. A one-way between subjects ANOVA was used to compare participant characteristics between racial groups. A two-way mixed model ANOVA was used to compare FMD between racial groups across menstrual phases. Data are presented as mean ± standard deviation. RESULTS: The present study included 20 WHW (25±6 years), 12 BLW (24±5 years), and 8 HW (24±4 years). Groups had similar cycle lengths (WHW 29±2; BLW 30±4; HW 31±5 days; p=0.61) and testing was conducted on similar days during each phase (data not shown, all p>0.05). Baseline brachial artery diameters were not different between races (p=0.68) or across phases (p=0.37). The vasodilatory response to FMD (FMD%) was not influenced by race (p=0.57) or phase (p=0.71) nor was there a significant interaction between race and phase (p=0.23) (WHW: EF 8.1±1.7, OV 7.5±2.8, ML 8.1±2.0%; BLW: EF 6.8±2.5, OV 6.9±2.3, ML 8.6±3.0%; HW: EF 8.2±2.4, OV 8.9±4.1, ML 7.6±2.3%). CONCLUSION: These preliminary findings indicate that macrovascular function assessed by FMD% does not change across the menstrual cycle, regardless of race. These data also suggest FMD% is a stable measure of macrovascular function in premenopausal women.

Flow-mediated slowing shows poor repeatability compared with flow-mediated dilation in non-invasive assessment of brachial artery endothelial function.

Pulse wave velocity (PWV) deceleration to reactive hyperemia–flow-mediated slowing (FMS)–has been suggested as an alternative method to flow-mediated dilation (FMD) to evaluate brachial artery endothelial function. FMS is suggested to address major caveats of the FMD procedure including its suboptimal repeatability and high-operator dependency. However, the repeatability of FMS has not been thoroughly examined, especially given the plethora of methods claiming to measure PWV. We assessed and compared the intra- and inter-day repeatability of FMS as measured by piezoelectric pressure mechanotransducers placed in the carotid and radial arteries, and brachial artery FMD as measured by echo-tracking. Twenty-four healthy male participants aged 23–75 yr, were examined on three separate days to assess intra and inter-day repeatability. All FMD and FMS examinations were conducted simultaneously by the same researcher complying with standardized guidelines. Repeatability was examined with intraclass correlation coefficient (ICC; >0.80), coefficient of variation (CV; <15%), and limits of agreement (95% LOA). Relative (%) FMD and FMS were scaled for baseline brachial artery diameter and PWV, respectively. Intra- (ICC: 0.72; CV: 136%; 95% LOA: -19.38 to 29.19%) and Inter-day (ICC: 0.69; CV: 145%, 95% LOA: -49.50 to 46.08%) repeatability of %FMS was poor, whereas %FMD demonstrated moderate-to-good intra- (ICC: 0.93; CV: 18%, 95% LOA: -3.02 to 3.75%) and inter-day repeatability (ICC: 0.74; CV: 25%, 95% LOA: -9.16 to 7.04%). Scaling FMD reduced the intra-day CV (-5%), and the uncertainty of the 95% LOA (- 37.64 to 35.69%) estimates of FMS. Carotid-radial artery FMS showed poorer repeatability compared to FMD.

Endothelial Function Does Not Show Signs of Impairment in Young Athletes At Two Months Post‐Covid‐19 Infection

It has been almost two years since the Covid‐19 pandemic hit, with over 5 million deaths globally. It is known that endothelial activation and dysfunction play a crucial role in Covid‐19 pathogenesis. Evidence of widespread endothelial injury is found in advanced cases of Covid‐19, especially in people with cardiovascular comorbidities. However, the effects of Covid‐19 on endothelial function in unique cohorts such as young athletes have been largely unexplored. This study evaluated endothelium function by noninvasive flow‐mediated dilation (FMD) in a sample of 14 college athletes (10M/4F, 18‐23 yrs, BMI, 23.8 ± 1.6 kg/m2) after testing positive for Covid‐19. All athletes had Covid‐19 with mild or no symptoms and did not require hospitalization. The study was performed 24 ± 10 days (13‐44 days) after having Covid‐19 positive tests. We also involved 10 BMI similar healthy young subjects as controls (7M/3F, 20‐25 yrs, BMI, 24.2±2.0 kg/m2). Baseline brachial artery diameters and the largest diameters after post cuff release were measured to calculate FMD. Brachial blood flow mean velocities and diameters were also recorded within 20 seconds after cuff release for calculating the shear rate (8 * mean velocity/ diameter). The baseline brachial artery diameter was significantly larger in the athlete group versus the control group (4.32±0.63 mm vs. 3.54±0.42 mm, p=0.02). The FMD was significantly lower in the athlete group than in the control group (6.49±2.05% vs. 11.05±4.08%, p=0.02). This finding is consistent with the previous reports that FMD was significantly lower in healthy athletes compared with controls. However, FMD adjusted for the ratio of flow‐mediated dilation and shear rate did not show a statistical difference between groups (0.058±0.028 %/s‐1 vs. 0.076±0.056 %/s‐1, p=0.33), even after evaluating baseline diameter as a covariate. Despite the need for extended acute and chronic observations and a healthy athlete control group, our findings suggest endothelial resilience in response to Covid‐19 infection in young athletes, which may explain their mild or asymptomatic status.

Effect of Acute Isometric Handgrip Exercise on Vascular Function in Children with Congenital Heart Disease

ObjectiveThe reactivity of conduit vessels such as the brachial artery is important in influencing arterial diameter, and subsequently, blood flow. Flow‐mediated dilation (FMD) measures vessel reactivity. The increase in shear stimuli from transient arterial occlusion enhances arterial diameter in an endothelial‐dependent manner, and this is thought to be impaired in individuals with congenital heart disease (CHD). Isometric handgrip (IHG) exercise is a proposed intervention to improve vessel reactivity by optimizing the shear stimuli to provoke changes in arterial diameter. Indeed, IHG training has been found to improve FMD in healthy adults and children. Whether IHG training improves endothelial dysfunction in CHD remains unknown. Improving vessel reactivity in the young becomes increasingly important in optimizing vascular health into adulthood. The effects of acute IHG exercise on the brachial artery were examined in children with CHD.HypothesisWe tested the hypothesis that acute IHG exercise would increase FMD in children with CHD.MethodsFour subjects with CHD (mean, 13 ± 1 year, 3 female) completed a single session of 4 × 2 mins of acute IHG (30% maximum voluntary contraction using the right hand) with 1‐min rest intervals between bouts. Before and after IHG exercise, the right brachial artery was imaged with Duplex ultrasound using a 1‐min baseline, 5 mins of forearm circulatory occlusion, followed by 3 mins of cuff deflation. Blood pressure and heart rate were measured continuously.ResultsPre‐FMD (baseline) mean arterial pressure (pre: 102 ± 17 mmHg vs. post: 110 ± 16 mmHg, p = 0.496) and heart rate (pre: 75 ± 13 bpm vs. post: 66 ± 5 bpm, p = 0.253) were not different. Baseline brachial artery diameter increased following acute IHG in 3 of 4 subjects (pre: 3.11 ± 0.45 mm vs. post: 3.23 ± 0.39 mm, Cohen’s d = 0.3). Peak shear rate was greater post‐IHG in 3 of 4 subjects (pre: 995 ± 346 sec‐1vs. post: 1158 ± 501 sec‐1, Cohen’s d = 0.4). FMD% (4.7% vs. 6.3% and 8.2% vs. 10.5%) and FMD% normalized to shear rate area under the curve (AUC) ratio (2.2E‐5 vs. 7.4E‐5 a.u. and 3.1E‐5 vs. 4.3E‐5 a.u., Cohen’s d = 2.0) increased post‐IHG in 2 of 4 subjects. When brachial artery diameter increased, peak shear rate, FMD%, and FMD% normalized to shear rate AUC improved post‐IHG in 2/3 subjects whereas subject four showed a decrease in brachial artery diameter, FMD% and FMD% normalized to shear rate AUC, with the exception of peak shear rate post‐IHG.ConclusionFavorable changes in brachial artery diameter, peak shear rate, FMD% and FMD% normalized to shear rate AUC following acute IHG may be a promising intervention for improving vascular tone and endothelial function in children with CHD.

An observational study of the endothelial dysfunction in type 2 diabetes mellitus and its association with risk factors

Background: Cardiovascular diseases (CVDs) are the major culprit to cause morbidity in type 2 diabetes mellitus (T2DM) patients. Endothelial dysfunction (ED) precedes the progressed stage of CVD presentation. This study aimed to study the risk factors for ED and identify the modifiable factors for risk reduction and provide caution measures. Materials and Methods: This cross-sectional observational study included 100 adult patients with T2DM on oral hypoglycemic drugs or insulin therapy. Based on glycemic control, type 2 diabetic patients were divided into four groups: Group 1 (poor glycemic control and hemoglobin A1C (HbA1c) >9%), Group 2 (fair glycemic control and HbA1c 8%–8.9%), Group 3 (good glycemic control and HbA1C 7–7.9%), and Group 4 (excellent glycemic control, HbA1C <7%). P < 0.05 was considered statistically significant. Results: Overall, significantly higher glycemic levels (fasting blood glucose, postprandial blood glucose, and HbA1c) and lipid derangements (cholesterol, low-density lipoprotein, and triglyceride) were found in patients with ED as compared to those without ED (P < 0.05). Baseline brachial artery diameter (D1) was into three groups, one group with D1 (≤3.6 mm) with mean flow-mediated dilatation (FMD) of 9.07%, Another group of D1 (3.61 mm to ≤4.30 mm) with mean FMD of 5.26%, and the third group with D1 (>4.41 mm) with mean FMD of 4.58%. There was a statistically significant association seen between baseline brachial artery diameter and FMD (P < 0.05). Multivariate linear regression showed that HbA1c and treatment of both Oral hypoglycemic agents (OHA) and insulin were the significant independent factors affecting the ED with OR of 7.566 (P = 0.0003) and 0.013 (P = 0.011), respectively. Conclusion: In diabetics, the risk of ED is increased with worsening levels of lipid profile and glycemia irrespective of the age and duration of the disease.

Sleep Efficiency is Inversely Associated with Brachial Artery Diameter and Morning Blood Pressure in Midlife Adults, with a Potential Sex-Effect.

PurposeSleep efficiency is inversely associated with cardiovascular risk. Brachial artery diameter and flow-mediated dilation (FMD) are noninvasive cardiovascular disease markers. We assessed the associations between sleep efficiency and these vascular markers in midlife adults, including people with sleep apnea.Patients and MethodsThirty (18 males) participants completed an in-laboratory 8-hour sleep opportunity beginning at their habitual bedtimes. Polysomnography was used to assess sleep patterns and sleep efficiency (time asleep/time in bed). We measured systolic and diastolic blood pressure, heart rate, and baseline diameter, and FMD immediately upon awakening in the morning. Mixed model analyses, adjusting for apnea-hypopnea and body mass indices, were used to assess the relationship between overnight sleep efficiency and cardiovascular markers. We also explored sex differences.ResultsSleep efficiency was negatively associated with baseline brachial artery diameter (p = 0.005), systolic BP (p = 0.01), and diastolic BP (p = 0.02), but not flow-mediated dilation or heart rate (p > 0.05). These relationships were confirmed with correlations between sleep efficiency and baseline diameter (r = −0.52, p = 0.004), systolic BP (r = −0.43, p = 0.017), and diastolic BP (r = −0.43, p = 0.019). There was a sex-specific interaction trend for sleep efficiency and arterial diameter (p = 0.07) and a significant sex-specific interaction (p < 0.05) for BP, such that the relationships between sleep efficiency and cardiovascular markers were significant in women but not in men.ConclusionIn midlife adults, poor sleep efficiency is associated with increased brachial artery diameter and blood pressure, effects that were primarily driven by significant associations in women. These associations could underlie the observed increase in cardiovascular risk in adults with poor sleep and cardiovascular disease.

Low-to-Moderate-Intensity Resistance Exercise Is More Effective than High-Intensity at Improving Endothelial Function in Adults: A Systematic Review and Meta-Analysis.

Aerobic exercise has been confirmed to improve endothelial function (EF). However, the effect of resistance exercise (RE) on EF remains controversial. We conducted this systematic review and meta-analysis on randomized controlled trials (RCTs) to determine the effect of RE and its intensities on EF. We searched Web of Science, PubMed/MEDLINE, Scopus, and Wiley Online Library, and included 15 articles (17 trials) for the synthesis. Overall, RE intervention significantly improved flow-mediated dilatation (FMD) in brachial artery (SMD = 0.76; 95% CI: 0.47, 1.05; p < 0.00001), which represents improved EF. Meta-regression showed that the RE intensity was correlated with changes in FMD (Coef. = −0.274, T = −2.18, p = 0.045). We found both intensities of RE improved FMD, but the effect size for the low- to moderate-intensity (30–70%1RM) was bigger (SMD = 1.02; 95% CI: 0.60, 1.43; p < 0.0001) than for the high-intensity (≥70%1RM; SMD = 0.48; 95% CI: 0.21, 0.74; p = 0.005). We further noticed that RE had a beneficial effect (SMD = 0.61; 95% CI: 0.13, 1.09; p = 0.01) on the brachial artery baseline diameter at rest (BADrest), and the age variable was correlated with the changes in BADrest after RE (Coef. = −0.032, T = −2.33, p = 0.038). Young individuals (<40 years) presented with a bigger effect size for BADrest (SMD = 1.23; 95% CI: 0.30, 2.15; p = 0.009), while middle-aged to elderly (≥40 years) were not responsive to RE (SMD = 0.07; 95% CI: −0.28, 0.42; p = 0.70). Based on our findings, we conclude that RE intervention can improve the EF, and low- to moderate-intensity is more effective than high-intensity.

068 Morning Cardiovascular Function in Chronic Cannabis Users and Healthy Controls

Abstract Introduction In the US cannabis is recreationally legal in 15 states and medically legal in 34 states. Preclinical studies suggest beneficial effects of cannabis on the cardiovascular system (e.g., vasorelaxation). Yet, acute cases of hospitalization after cannabis consumption indicate potential adverse cardiac effects. Vascular endothelial function is a marker of cardiovascular disease and is measured as a change in resting brachial artery diameter (flow-mediated dilation, FMD) during reactive hyperemia. Both resting diameter (positively) and FMD response (negatively) are associated with cardiovascular risk. Resting diameter likely depends on long-term structural changes, and FMD response mostly depends on nitric oxide. Reactive hyperemia is more complex and depends on numerous variables, including adenosine and prostaglandins. FMD is attenuated in the morning when the frequency of adverse cardiovascular events peaks. To begin to understand the effects of chronic cannabis use on the cardiovascular system, in this pilot study, we compared morning measurements of vascular endothelial function, blood pressure, and heart rate between chronic cannabis users and controls while controlling for prior nighttime sleep opportunities. Methods Participants, cannabis non-users (n=5) and users (n=4), 44% female, age 25.4 ± 3.6 years - no demographic differences between groups, kept a consistent 2-week sleep schedule at home followed by an 8h sleep opportunity at their habitual time in the laboratory. Upon-wakening, we measured resting blood pressure, heart rate, baseline diameter, hyperemic response, and FMD. Statistical differences between groups were calculated using a two-tailed t-test. Results Systolic and diastolic blood pressures (p=0.13 and 0.26 respectively), heart rate (p=0.97), and FMD response (p=0.99) did not differ between groups. However, chronic cannabis users had a significantly higher baseline brachial artery diameter (mean difference: 1.04 mm ± 0.26, p=0.005), and lower hyperemic response (mean difference: -7944 iu/s ± 2538, p=0.02) compared to non-users. Conclusion These preliminary findings suggest that chronic cannabis consumption may be associated with adverse structural and functional changes in the vasculature of otherwise healthy young adults. Based on these initial observations, cannabis may act on the cardiovascular system via non-nitric oxide mechanisms. However, it is necessary to increase our sample size to test the robustness of these findings. Support (if any) KL2TR002370, AASM

Impact of Family History of Hypertension on Racial Differences in Flow‐Mediated Dilation and Reactive Hyperemia

The prevalence of hypertension and cardiovascular disease is highest in non-Hispanic black (BK) individuals. This has led to a number of studies investigating potential racial differences in vascular function, assessed as flow-mediated dilation (FMD, macrovascular function) and reactive hyperemia (RH, microvascular function). These studies suggest that otherwise healthy BK individuals may have reduced vasodilator responses, compared to white (WH) individuals. However, it is notable that these studies did not consider the participants' family history of hypertension (FHH), which is important because studies have shown that individuals with a positive (+) FHH exhibit blunted vasodilator function compared to those with no FHH (-FHH). Hence, whether the higher prevalence of +FHH among BK individuals contributed to the previously reported differences in FMD and RH between BK and WH individuals is unknown. Thus, we aimed to investigate the impact of FHH on FMD and RH in BK and WH males. We hypothesized that FMD and RH would be attenuated in BK compared to WH males, and further, a +FHH would reduce FMD and RH compared to a -FHH in both groups. We studied 17 young healthy BK (+FHH: n = 9) and WH males (+FHH: n = 9). Heart rate (ECG) and brachial artery diameter and blood velocity (duplex Doppler Ultrasound) were continuously measured while subjects laid supine. Baseline measures were recorded for 2 min, following which a cuff placed around the forearm was rapidly inflated to 220 mmHg for 5 min. All measurements were recorded for 30 s prior to and 3 min after cuff release. FMD was quantified as a percent change in brachial artery diameter from baseline to peak diameter after cuff release. The impact of shear rate on FMD was controlled for statistically using an ANCOVA. RH was quantified as peak blood velocity and hyperemic blood velocity area under the curve (AUC) to 60s after cuff release. Baseline brachial artery diameter and blood velocity were not different between groups (P > 0.05 for all comparisons). FMD was significantly blunted in BK (4.12 ± 0.64%, Mean ± SE) compared to WH males (6.00 ± 0.49%; P = 0.025), and remained significantly blunted after controlling for impact of shear rate on FMD (BK: 4.19 ± 0.58% vs. WH: 5.93 ± 0.58%; P = 0.046). There was no effect of FHH on FMD in either race (interaction and main effect of FHH P > 0.05). Likewise, RH was significantly blunted in BK compared to WH males when quantified as peak blood velocity (BK: 58 ± 3 cm.s-1 vs. WH: 70 ± 4 cm.s-1, P = 0.025), as well as hyperemic blood velocity AUC to 60s (BK: 1419 ± 85 a.u. vs. WH: 1738 ± 123 a.u., P = 0.041), with no effect of FHH in either race (interaction and main effect of FHH P > 0.05 for both measures). These preliminary findings suggest that young healthy BK males exhibit attenuated FMD and RH compared to their WH counterparts; an effect that appears to be independent of FHH.

EFFECT OF BLOOD PRESSURE OPTIMISATION ON ENDOTHELIAL FUNCTION IN PATIENTS WITH ATRIAL FIBRILLATION AND HYPERTENSION

Objective: Hypertension accounts for more cases of atrial fibrillation (AF) than any other risk factors. AF and hypertension commonly co-exist and both are associated with endothelial dysfunction. FMD measurement using a high-resolution ultrasound has become a reliable and reproducible technique for assessment of endothelial dysfunction. To investigate whether optimising of blood pressure (BP) in patients with hypertension and AF leads to improvement in FMD. Design and method: In a longitudinal comparison, we recruited 30 participants with hypertension and permanent AF. Each participant had 3 serial BP readings and an echocardiogram. Their drug history was noted. High-resolution ultrasound was used to measure brachial artery diameter at rest and during reactive hyperaemia (endothelium-dependent FMD). Participant's BP medication was optimised according to their BP. Participants were then followed them up after 8 weeks for repeat FMD measurements. Data analysis was carried out using paired t-test on SPSS. Results: Following optimisation of BP medication, patients with permanent AF and hypertension were followed up after 8 weeks and FMD repeated. There was significant improvement in mean heart rate (77 ± 18 (baseline) vs 72 ± 17 (follow up), p = 0.01), systolic BP (140 mmHg [128 – 148] (baseline) vs 131 mmHg [122 – 146] (follow up), p = 0.03), diastolic BP (81 mmHg ± 13 (baseline) vs 77 mmHg ± 12 (follow up), p = 0.02) and mean arterial pressure (MAP) (100 mmHg ± 9 (baseline) vs 97 mmHg ± 13 (follow up), p = 0.01). Both groups had a similar baseline brachial artery diameter (p = 0.34). Endothelium-dependent FMD response was better following 8 weeks of BP optimisation but this was not significant (3.1%, 95% CI [2.3 – 4.8] (baseline) vs 5.2%, 95% CI [3.9 – 6.5] (follow up), p = 0.09). No variables were identified on univariate or multivariate analysis as independent predictors of FMD. Conclusions: Endothelial dysfunction can be improved following optimisation of BP medication suggesting modulation of endothelial function is possible in patients with permanent AF and hypertension. Longer-term improvement in FMD may have a prognostic implication.

Aerobic exercise, but not isometric handgrip exercise, improves endothelial function and arterial stiffness in patients with myocardial infarction undergoing coronary intervention: a randomized pilot study

BackgroundAerobic exercise improves endothelial function and arterial stiffness after myocardial infarction (MI), but the effects of isometric exercise on cardiovascular parameters are still uncertain. We aimed to assess the effects of one session of aerobic or isometric exercise on flow-mediated dilation (FMD) and pulse wave velocity (PWV) in post-MI volunteers undergoing percutaneous coronary intervention (PCI).MethodsTwenty post-MI patients undergoing PCI were randomized to aerobic (AE, n = 10) or isometric (IE, n = 10) exercise groups. We evaluated cardiac structure and function (echocardiographic); carotid plaque presence (ultrasound). FMD and PWV were measured 10 min before and 10 min after the intervention: a single session of moderate-intensity AE (30 min; ratings 12–14 on Borg’s scale or 50–60% HRreserve) or handgrip IE (four two-minute bilateral contractions; 30% maximal voluntary contraction; 1-min rest). Generalized estimating equations (Bonferroni post-hoc) was used to assess differences (p ≤ 0.050).ResultsFMD improved only in the AE group (Δ = 4.9%; p = 0.034), with no difference between groups after exercise. Even after adjustment (for baseline brachial artery diameter) the effectiveness of AE remained (p = 0.025) with no change in the IE group. PWV was slightly reduced from baseline in the AE group (Δ = 0.61 m/s; p = 0.044), and no difference when compared to the IE group. Peripheral vascular resistance decreased in AE versus IE (p = 0.050) and from baseline (p = 0.014).ConclusionsVascular measurements (FMD and PWV) improved after a single session of AE. There are apparently no benefits following a session of IE.Trial registrationhttp://www.clinicaltrials.gov and ID number NCT04000893.

Flow-Mediated Dilatation of the Brachial Artery for Assessing Endothelial Dysfunction in Children with Moyamoya Disease

Background: Moyamoya disease is a progressive, steno-occlusive arteriopathy involving the internal carotid artery and its branches and causing recurrent stroke episodes in children. Patients with moyamoya disease may be more susceptible to influences that cause endothelial dysfunction. We evaluated whether flow-mediated dilatation (FMD) of the brachial artery is useful for assessing endothelial dysfunction in children with moyamoya disease. Methods: This prospective observational study included 30 children with moyamoya disease and 30 controls. After anesthesia induction, a blood pressure cuff was applied to the forearm and inflated to a pressure that was 50 mm Hg above the baseline systolic blood pressure for 5 min. From 30 s before to 2 min after deflation, the brachial artery diameter was recorded on ultrasound. The increase in internal diameter was expressed as the percentage of the baseline diameter. Results: Fifty-nine patients were analyzed. Baseline brachial artery diameters in the moyamoya and control groups were 3.00 and 3.37 mm, respectively (p = 0.004; difference, 0.38; 95% CI 0.12–0.63), while those after deflation were 3.06 and 3.48 mm, respectively (p = 0.003; difference, 0.42; 95% CI 0.15–0.68). The percent change of the baseline diameter value was 4.0% in the disease group and 8.3% in the control group (p = 0.10). There was a group and time interaction for brachial artery diameter (p = 0.01; main effect of group, p = 0.009; main effect of time, p = 0.007). Conclusion: FMD of the brachial artery may not be enough for determining endothelial dysfunction under general anesthesia in children with moyamoya disease.

Dietary macronutrients do not differently affect postprandial vascular endothelial function in apparently healthy overweight and slightly obese men

PurposeWell-designed trials comparing side-by-side effects of macronutrients on postprandial endothelial function are missing. Therefore, we investigated under well-controlled and isocaloric condition effects of fat, carbohydrates, and protein on postprandial endothelial function as assessed by brachial artery flow-mediated vasodilation (FMD), an important non-invasive technique to assess endothelial function.MethodsEighteen apparently healthy overweight and slightly obese men (BMI 26.0–35.0 kg/m2) completed this randomized, double-blinded, cross-over trial. The study consisted of three test days each separated by a wash-out period of at least 1 week. After an overnight fast, men received an isocaloric meal providing 3987 kJ (953 kcal) that was either high in dietary fat (En% fat [F]/carbohydrates [C]/protein [P]: 52.3, 39.2, 8.0), carbohydrates (En% F/C/P: 9.6, 81.5, 8.6), or protein (En% F/C/P: 10.6, 51.5, 36.9). Fasting and 2-h postprandial FMD responses were measured.ResultsA postprandial decrease of 1.2% point in FMD was observed after the high-protein meal (P = 0.015). However, postprandial changes did not differ between meals (P = 0.45). An increase in baseline brachial artery diameters was observed after the high-protein meal (P < 0.001) and changes differed between meals (P = 0.020). A meal*time interaction was found for plasma glucose concentrations, with the most pronounced increases after the high-carbohydrate meal at T15, T30, T60, and T90 (P < 0.05). A significant time and meal (P < 0.001), but no time*meal effect (P = 0.06) was found for serum insulin concentrations. Increases in serum triacylglycerol concentrations did not differ between meals (P = 0.014).ConclusionMacronutrients did not differently affect postprandial endothelial function in apparently healthy overweight and slightly obese men.Trial registrationTrial registration number (ClinicalTrials.gov) NCT03139890 in May 2017