Brachial Artery Responses Research Articles

Sustained paradoxical vasodilation and blood pressure lowering in response to sympathetic stimulation as markers of disease severity and poor survival in primary AL amyloidosis.

Abstract Background AL patients present sustained paradoxical vasodilation in response to sympathetic stimulation by cold pressor test (CPT). The clinical relevance of this finding is unknown. Purpose We investigated the association between CPT-induced vascular and hemodynamic responses with clinical characteristics of the disease in AL amyloidosis. Methods We consecutively recruited 113 newly diagnosed patients with AL amyloidosis before treatment initiation. High resolution ultrasonography was used to measure the maximum vasodilation of the brachial artery in response to a cold stimulus and 3 minutes after its withdrawal. Systolic (SBP) and diastolic blood pressure (DBP) were measured at the same timepoints. Clinical and laboratory makers of autonomic dysfunction were also measured in a subgroup of the population. All-cause and cardiovascular (CV) mortality were defined as end-points of the study. Results Sustained vasodilation post CPT (%pCPT) was associated with markers of autonomic dysfunction, namely dipping status (p<0.05) and sudomotor dysfunction (p=0.064) and with NYHA stage, baseline NTproBNP and heart failure (p<0.05 for all). DBP%pCPT was associated with the neuropathy symptom scale (NSS Autonomous, p=0.032), while SBP%pCPT was inversely associated with Mayo stage. Vasodilation%pCPT was independently associated with CV death (adjusted HR=1.154, p=0.017) while both DBP%pCPT (HR=0.955, p=0.027) and SBP%pCPT (HR=0.947, p=0.04) were independently associated with all cause death (adjusted for the core model including age, sex, SBP, Mayo stage and nerve involvement). Overall survival was worse in AL patients who demonstrated a decrease in SBP%pCPT than in those who exhibited an increase or kept it stable (log rank test, p=0.024). The same applies to DBP%pCPT(log rank test, p=0.002). Regarding CV death, Vasodilation%pCPT above 5.86% was associated with increased risk of CV death (log rank test, p=0.002). Conclusions In AL amyloidosis, sustained paradoxical vasodilation and decreased SBP and DBP in response to sympathetic stimulation were associated with autonomic dysfunction, more severe cardiac involvement and poor survival.

Five weeks of intermittent hand exposures to alternating cold and hot stimuli do not modify finger cold-induced vasodilatation response.

We tested the hypothesis that prolonged intermittent hand exposures to transient contrast thermal stimuli would enhance the finger cold-induced vasodilatation (CIVD) response during localized cooling. Eight healthy men participated in a 5-week regimen, during which they immersed, thrice per week, the non-dominant (EXP) hand in 8° and 43°C water, sequentially and at 3-min intervals, for a total period of 60min. The contralateral (i.e., dominant) hand served as the control (CON) hand. Before and after the regimen, subjects conducted two 30-min hand cold (8°C water) provocation trials, one with the EXP hand and the other with the CON hand. In addition, a flow-mediated dilatation test was performed in the brachial artery of the EXP arm. Regardless of the hand tested, the average finger skin temperature [CON hand: pre-trial=10.5 (1.2)°C, post-trial=10.8 (1.3)°C and EXP hand: pre-trial=10.7 (1.1)°C, post-trial 10.9 (1.1)°C; p=0.79], and the incidence of CIVD events [CON hand: pre-trial=1.1 (1.2) events, post-trial=1.2 (1.1) events and EXP hand: pre-trial=1.1 (0.8) events, post-trial=1.1 (0.8) events; p=0.88] were not affected by the 5-week regimen. The sensation of cold-induced pain was transiently alleviated following the regimen (p=0.02). The flow-mediated dilatation response of the EXP brachial artery remained unaltered [pre-trial=5.4 (3.2)%, post-trial=4.7 (3.6)%; p=0.51]. Therefore, five weeks of intermittent hand exposures to alternating cold and hot stimuli do not improve finger temperature responsiveness to sustained localized cold.

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.

Роль корекції ендотеліальної дисфункції в комплексній профілактиці гіпертензивних ускладнень вагітності

Purpose - to study the effect of correction of endothelial dysfunction by the introduction of L-arginine in the comprehensive prevention of the development of severe hypertensive disorders in pregnant women. Materials and methods. The division into groups was carried out indiscriminately following the prescribed bath. 27 women reached the 1st group, who, in addition to basic prevention of preeclampsia (small doses of aspirin for 12 days, calcium supplement 1000 mg per dose for 16 years), took Tivortin until conception and p. It's an hour of urgency; up to the 2nd group - 54 women who did not receive basic prevention of preeclampsia. The control group (3) consisted of 16 healthy women with physiological changes in vagusity. Participants of the 1st group, during the hour of stay in the hospital, took L-arginine internally (iv) (4 g) + 2 teaspoons 2 times (4 g) per os per dose 40 minutes before admission, then 3 teaspoons spoons 2 times (6 g per dose). The average intensity of the droplets became 6. The function of the endothelium was evaluated according to the universally recognized non-invasive cuff test method, which is based on the principle of ultrasound assessment of the change in the diameter of the brachial artery in response to the restoration of blood flow in it after short-term compression of the upper limb with a cuff. Physical condition and endurance were assessed using the generally accepted 6-minute walk method. The quality of life in pregnant women who had experienced severe preeclampsia in the past was assessed in stages - according to the health-related quality of life (HRQoL) scale and the scale created by the World Health Organization (WHOQOL-BREF). Results. Arterial hypertension and preeclampsia are based on changes in endothelium-dependent vasodilatation. A positive effect on the function of the endothelium significantly improves indicators of physical well-being and quality of life. When conducting a test with a 6-minute walk in the Group 1, better indicators were found than in the Group 2 (respectively, 409±23 m vs. 381±32 m, p<0.05), this indicator in the control group was 473±32 m (p<0.05 according to the Groups 1 and 2). However, this indicator significantly improved in pregnant women of the Group 1 after intravenous administration of L-arginine: 441±12 m (p<0.05 compared to the indicator before intravenous administration). According to the assessment of the quality of life of pregnant women of the studied groups, it should be noted that the quality of life indicators in all domains are significantly lower in women of the Group 1, which is associated with significantly worse anamnesis data of such women, significant concern about the results of the next pregnancy. When evaluating indicators of endothelium-dependent and endothelium-independent vasodilatation, it was found that in the group of women who received L-arginine preconceptionally, in the 1st trimester, the indicator before intravenous IV administration was 5.09±0.44, and after - 8.21±0.24, which indicates a significant improvement in endothelium-dependent vasodilation indicators (by 49.1%) 28-32 weeks, there are also no births of children with a body weight of less than 1500 g. Conclusions. In the group of high-risk pregnant women, the use of L-arginine in the complex prevention of preeclampsia allows to reduce the risks of early severe preeclampsia, to reduce the medication burden of two- and three-component hypotensive therapy. An increase in physical endurance, quality of life, and improvement in pregnancy outcomes are due to a positive effect on the function of the endothelium through the optimization of endothelium-dependent vasodilatation associated with the provision of the L-arginine substrate for the full synthesis of nitric oxide. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

Abstract 12217: Effect of Repeated Binge Drinking in Mid-Life Adults on Vascular Function

Introduction: Age-related changes in vascular function, including endothelial dysfunction and arterial stiffening, contribute to the development of cardiovascular disease. “Mid-life adults”, defined as age 50-64, begin to show signs of vascular aging. One in five mid-life adults engage in binge drinking and our previous studies in young adults showed that repeated binge drinking was associated with endothelial dysfunction and arterial stiffening. However, it is unclear how binge drinking influences vascular function in aged individuals. Therefore, the purpose of this study is to investigate endothelial function and arterial stiffness in mid-life adults who binge drink regularly (binge drinkers) compared to those who did not drink alcohol (alcohol abstainers). Methods: Twelve apparently healthy mid-life men and postmenopausal women, with no smoking history were included in this study (mean±SEM, age: 57±1 years, body mass index: 26.0±0.8 kg/cm 2 , systolic blood pressure: 119±5 mmHg). Alcohol use was assessed by the Alcohol Use Disorders Identification Test (AUDIT) and dried blood spot phosphatidylethanol. Endothelial function was assessed by brachial artery response to reactive hyperemia (flow-mediated dilation, FMD) via ultrasonography. Arterial stiffness was assessed by carotid to femoral pulse wave velocity (cfPWV) via use of the cuff-based SphygmoCor Xcel. Results: Binge drinkers (n=6) had an AUDIT score≥5 (11.8±2.1) and positive phosphatidylethanol level (162±103 ng/mL), while alcohol abstainers (n=6) had an AUDIT score≤1 (0.8±0.2) and negative phosphatidylethanol level. Compared to alcohol abstainers, binge drinkers had a lower brachial artery FMD (alcohol abstainers vs. binge drinkers: 9.8±1.2% vs. 5.1±0.9%, P=0.01), but similar cfPWV (7.2±0.7 vs. 7.0±0.5 m/sec, P=0.8). Conclusions: Our results indicate that compared to mid-life adult alcohol abstainers, binge drinkers had lower endothelial function, but similar arterial stiffness. These findings suggest that repeated binge drinking may further impair endothelial function throughout the aging process.

Abstract 268: Single Cell Gene Expression Of Brachial Artery In Response To Increased Shear Stress

Blood flow dynamics modulate vascular development, homeostasis, and contribute to vascular pathobiology. However, it is unknown how shear stress influences cellular transcriptomics of the arterial wall. Two-stage hemodialysis access surgeries provide an opportunity to compare native vessel to vessel after exposure to significantly altered hemodynamics. Single-cell sequencing was performed on brachial artery samples obtained from 3 patients at the time of 1 st and 2 nd stage surgery. Arterial cellular composition and temporal changes in gene expression were quantified after sequencing and functional analyses were performed on differentially expressed genes. Compositional changes and gene expression dynamics were highest in the smooth muscle cell (SMC) populations followed by fibroblasts. SMCs were clustered into contractile (classical) and “modified” populations, with the latter having lower expression of contractile markers. Downregulation of transcription factor ARNTL was the most significant controller in contractile SMCs and fibroblasts, and second behind HIF1α in modified SMCs. Macrophages had a significant increase in composition, but few dynamic genes suggest a return to quiescence. Endothelial cells showed minimal changes with dynamic genes responding to mechanical stimulus. Ingenuity pathway analysis revealed activation of EIF2 signaling in both SMC and fibroblast clusters, promoting translation. The top divergent pathway among SMC clusters is PI3/AKT signaling, with increased vascular remodeling, proliferation and cell death in the contractile group. Cellular processes are overall downregulated in modified SMCs, which represent the majority of SMCs after vascular adaption. This study is the first single-cell characterization of normal human artery and its cellular response to increased hemodynamic forces, specifically detailing cellular compositional changes and their associated dynamic genes.

Single Cell Gene Expression Of Brachial Artery In Response To Increased Shear Stress

Single Cell Gene Expression Of Brachial Artery In Response To Increased Shear Stress

CHARACTER OF IHD COURSE IN WOMEN OF CLIMACTERIC AGE

Menopause is one of the factors that impair the function of the endothelium of the vascular wall. In patients with coronary artery disease in this age group, with ultrasound examination of the brachial artery, there is a violation of endotheliumdependent relaxation, which is manifested by a decrease in the increase in the diameter of the brachial artery in response to reactive hyperemia or paradoxical vasoconstriction. Changes in endothelial reactivity can be considered an early manifestation of atherosclerosis.

Effects of autonomic nervous system activation on endothelial function in response to acute exercise in hypertensive individuals: study protocol for a randomized double-blind study

BackgroundArterial hypertension has a direct association with endothelial dysfunction and major cardiovascular events. There is evidence showing the benefits of aerobic exercise on flow-mediated dilation (FMD) in hypertensive individuals but little is known about the effect of autonomic nervous system (ANS) activation on FMD of the brachial artery in response to different types of exercise in this specific population. This study aims to examine the effects of ANS activation on FMD of the brachial artery in response to exercise in hypertensive individuals following a session of different types of exercise including aerobic exercise (AE), resistance exercise (RE), or combined exercise (CE).MethodsThirty-nine hypertensive volunteers aged 35 to 55 years will be randomly assigned to two exercise sessions: AE (40 min on a cycle ergometer at 60% of HR reserve), RE (4 lower limb sets with 12 repetitions at 60% 1-RM for 40 min), or CE (RE for 20 min + AE for 20 min). Each exercise group will be randomized to receive either an α1-adrenergic blocker (doxazosin 0.05 mg/kg−1) or placebo. Ultrasound measurement of FMD is performed 10 min before and 10, 40, and 70 min after exercise. ANS activation is monitored using a Finometer and measurements are taken during 10 min before each FMD assessment. Arterial stiffness is assessed by pulse wave velocity (PWV) analysis using a Complior device.DiscussionWe expect to demonstrate the effect of ANS activation on FMD of the brachial artery in hypertensive individuals in response to different types of exercise. This study may give some insight on how to improve exercise prescription for hypertension management.Trial registrationhttps://clinicaltrials.gov and ID "NCT04371757". Registered on May 1, 2020.

English

BACKGROUND Evaluation of endothelial function in isolated coronary artery ectasia (ICAE) with flow-mediated dilation (FMD) is limited and use of flow mediated vasodilation as a surrogate marker for the extent of coronary atherosclerosis remains unknown. Thus, the following study was done to evaluate for endothelial dysfunction (ED) in subjects with ICAE by assessing the FMD in the brachial artery. METHODS This was an observational study, conducted at a referral hospital providing tertiary care in India between June 2017 and November 2018. Fifty patients with ICAE and fifty control patients with normal coronary arteries (NCA) on coronary angiogram, done by using a standard Seldinger technique via femoral route, were the subjects of the study. Brachial artery FMD was determined by using a highresolution ultrasound system (Samsung RS80A) using a linear transducer of a frequency of 7.5 Mega Hertz. RESULTS The groups had same baseline characteristics in terms of age, sex etc. (all P values > 0.05). However, values of serum uric acid and low-density lipoproteins were statistically significantly higher in ICAE subjects (P < 0.0001). Whereas, dilatation of brachial artery in response to shear stress was significantly lower in patients with ICAE subjects than in patients with normal coronaries. (8.85 ± 0.49 vs. 12.83 ± 0.45, P < 0.0001). Marki’s classification, type 1, type 2, type 3 and type 4 coronary artery ectasia (CAE) was present in 8 (16 %), 4 (8 %), 13 (26 %), and 25 (50 %), respectively. CONCLUSIONS Atherosclerosis may play a pivotal role in the genesis of ICAE. Hyperlipidaemia may have a specific role in the disease process. Further research is required to evaluate the exact molecular mechanisms involved in CAE. KEYWORDS Coronary Artery Disease, Ectasia, Endothelial Dysfunction, Hyperlipidaemia

Acute dose-response effect of coffee-derived chlorogenic acids on the human vasculature in healthy volunteers: a randomized controlled trial

ABSTRACTBackgroundEpidemiological studies have reported lower risk of cardiovascular disease with moderate coffee consumption. In addition, emerging evidence indicates that consumption of coffee beverages enriched in chlorogenic acids (CGAs) may influence blood pressure and endothelial function, suggesting that the beneficial cardiovascular effect of coffee may relate to its CGA content.ObjectivesWe conducted a double-blind randomized crossover trial to test the effect of acute consumption of a decaffeinated green coffee extract (DGCE), rich in CGAs, on endothelial function in healthy subjects.MethodsWe compared 3 different doses of DGCE (302, 604, and 906 mg, respectively) with a placebo. Endothelial function was defined as the percentage change in the internal diameter of the brachial artery in response to flow-mediated dilation (%FMD). In addition, we followed the plasma concentration-time profiles of 25 systemic CGA metabolites over 24 h after DGCE consumption and we explored the relation between systemic concentrations of CGAs and the effect on %FMD.ResultsThe DGCE formulations containing different amounts of CGAs resulted in dose-proportional increases in overall total polyphenol concentrations. The systemic appearance of total CGAs was biphasic, in agreement with previous results suggesting 2 sites of absorption in the gastrointestinal tract. Compared with the placebo group, a significant FMD increase (>1%) was observed 8.5, 10, and 24 h after consumption of 302 mg DGCE (∼156.4 mg CGAs). The differences with placebo observed in the other 2 groups were not statistically significant. Evaluation of the relation between phenolic exposure and %FMD showed a positive tendency toward a larger effect at higher concentrations and different behavior of CGA metabolites depending on the conjugated chemical position.ConclusionsWe demonstrated an acute improvement in %FMD over time after ingestion of a DGCE, explained at least partly by the presence in the blood circulation of CGAs and their metabolites. This trial was registered at clinicaltrials.gov as NCT03520452.

Brachial Artery “Low-Flow Mediated Constriction” Is Associated with Myocardial Perfusion Defect Severity and Mediated by an Altered Flow Pattern during Occlusion

Introduction: The relationship between low flow-mediated constriction (LFMC), a new proposed measure of endothelial function, with cardiovascular disease severity and its hypothesized stimulus, that is, low flow, has not been comprehensively evaluated. The study evaluated association between change in brachial artery diameter during constriction with severity of myocardial perfusion defect (PD) and alterations in different components of flow profile. Methods: Brachial artery responses to occlusion were assessed in 91 patients and 30 healthy subjects. Change in anterograde and retrograde blood flow velocities (delta anterograde blood flow velocity and retrograde blood flow velocity), anterograde shear rate and retrograde shear rate (delta ASR and RSR, respectively), and oscillatory shear index (delta) during forearm occlusion at 50 mm Hg above systolic pressure, from baseline was calculated. Myocardial perfusion was evaluated in patients using exercise single positron emission computed tomography and % myocardial PD was calculated from summed stress score. Results: LFMC emerged as independent predictor of defect severity after correcting for age and gender (p = 0.014). Sixty-seven patients (73.6%) and 15 healthy subjects (50%) showed constriction during occlusion. In stepwise backward regression analysis, RSR contributed 35.5% and ASR contributed 20.1% of the total 63.9% variability in artery diameter during occlusion. Conclusion: The results suggest that LFMC is independently associated with myocardial perfusion severity and is “mediated” by an altered flow profile during occlusion.

The Low–Flow-Mediated Arterial Constriction in the Upper Limbs of Healthy Human Subjects are Artery Specific and Handedness Independent

Low–flow-mediated constriction (LFMC) has been used to assess resting endothelial function in peripheral conduit arteries. The literature describes discrepancies in the behaviour of radial versus brachial artery in response to low-flow state, the reasons for which were not addressed in a systematic and scientific way. Moreover, the influence of handedness on observed LFMC responses has not been investigated. The present study aimed at systematic measurement and comparison of the LFMC responses in radial and brachial arteries of both dominant and non-dominant arms of healthy human volunteers. We also investigated the physiological factors associated with differential LFMC response of radial versus brachial artery in the same group of subjects. Longitudinal B mode ultrasonographic cine loops of radial and brachial arteries were acquired at baseline and after producing distal circulatory arrest. Cine loops were screen grabbed and analyzed later using automated edge detection algorithms to measure end-diastolic diameters. Distal circulatory arrest was produced over the proximal forearm (for the brachial artery) and over the wrist (for the radial artery) at 250 mm Hg for 5 min after baseline measurements. Results suggested that arterial location (p = 0.0001) and baseline diameter (p < 0.0021) emerged as independent predictors of LFMC response. Differences in the LFMC responses are handedness independent and could be attributed to the arterial location along with the differences in their baseline diameters.

Endothelial function in response to exercise in the cold in patients with coronary artery disease.

Regular long-term physical exercise has favourable effects on endothelial function in patients with coronary artery disease (CAD). However, the effects of an acute exercise bout in the cold on endothelial function are not known. At first, the effects of moderate-intensity aerobic lower-body exercise were assessed in CAD patients (n=16) in a neutral [+22°C] and cold [-15°C] environment. Secondly, responses to static and dynamic upper-body exercise in a neutral [+22°C] and cold [-15°C] environment were investigated in CAD patients (n=15). All experiments were performed in a random order. Endothelial function was measured by flow-mediated dilation (FMD) of the brachial artery in response to reactive hyperaemia, before and after the exposures in a neutral environment. No significant temperature*exercise*condition (pre-post) interaction was observed in FMD% when comparing rest versus aerobic exercise or static versus dynamic upper-body exercise. Relative reactive hyperaemia during FMD protocol, measured by changes in shear rate, was elevated after rest compared to aerobic exercise (p=.001) and after static compared to dynamic upper-body exercise (p<.001). However, no significant temperature*exercise*condition interaction was observed when FMD% was normalizedfor shear rate. Endothelial function to an acute bout of exercise among CAD patients was not modified by the environmental temperature where the exercise was performed. The present findings argue against the hypothesis that exercise in cold environmental conditions impairs endothelial function in patients with CAD.

Endothelial function and plasma matrix metalloproteinase-2 levels and their association with the size and elastic properties of the ascending aorta in first-degree relatives of bicuspid aortic valve patients.

To explore endothelial function and plasma matrix metalloproteinase-2 levels and their association with the size and elastic properties of the ascending aorta in the first-degree relatives (FDRs) with tricuspid aortic valve (TAV) of individuals with bicuspid aortic valve (BAV). Twenty-six patients with BAV without significant valvular dysfunction, 35 FDRs with TAV, and 29 matched healthy controls were analyzed. Two-dimensional echocardiography and high-resolution ultrasound were applied to evaluate the size and elasticity of the ascending aorta and the flow-mediated vasodilation (FMD) of the brachial artery in response to hyperemia. The aortic diameter was larger in the BAV patients than in the FDRs and controls, and the aortic elastic properties showed larger decreases in the BAV patients. The FDRs had a larger aortic diameter and more impaired elastic properties than the controls. The BAV patients had a significantly lower FMD than the FDRs and controls (P<.001), while the FMD was lower in the FDRs than in the controls (P<.001). The plasma MMP-2 levels were significantly higher in the BAV patients than in the FDRs (P=.001) and controls (P<.001). Additionally, the FDRs had higher plasma MMP-2 levels than the controls (P<.001). Pearson correlation analysis revealed that the aortic diameter, distensibility, stiffness index, and strain were significantly associated with FMD and plasma MMP-2 levels. Aortic enlargement and impaired elasticity in the FDRs with TAV were associated with impaired endothelial function and increased plasma MMP-2 concentrations.

Microvascular blood flow during vascular occlusion tests assessed by diffuse correlation spectroscopy

What is the central question of this study? What are the characteristics of the time courses of blood flow in the brachial artery and microvascular beds of the skin and skeletal muscle following transient ischaemia? What is the main finding and its importance? Skeletal muscle blood flow was significantly slower than the transient increase in the cutaneous tissue, suggesting mechanistic differences between cutaneous and muscular blood flow distribution after transient ischaemia. These results challenge the use of the cutaneous circulation as globally representative of vascular function. Vascular function can be assessed by measuring post-occlusion hyperaemic responses along the arterial tree (vascular occlusion test; VOT). It is currently unclear if responses are similar across vascular beds following cuff release, given potential differences in compliance. To examine this, we compared laser Doppler-derived blood flux in the cutaneous circulation (LDFcut ) and skeletal muscle microvascular blood flux (BFI) using diffuse correlation spectroscopy (DCS), to brachial artery blood flow (BABF) during VOT. We hypothesized that during a VOT following cuff release, (1) BFI response would be delayed compared to the brachial artery response, and (2) time to peak blood flux in the cutaneous vasculature would be slower than both brachial artery and skeletal muscle responses. Seven healthy men (26±4years) performed three trials of a brachial artery VOT protocol with 10min of rest between trials. A combined DCS and near-infrared spectroscopy probe provided BFI and oxygenation characteristics (total-[haem]), respectively, of skeletal muscle. BABF was determined via Doppler ultrasound and microvascular cutaneous blood flux was determined via LDFcut . Following cuff release, time to peak of BFI (32.3±6.0s) was significantly longer than BABF (7.3±2.5s), LDFcut (10.0±6.4s) and total-[haem] (14.2±8.3s) (all P<0.001). However, time to peak of BABF, LDFcut and total-[haem] were not significantly different (P>0.05). These results suggest mechanistic differences in control of cutaneous and muscular blood flow distribution after transient ischaemia.

Hemodynamic and autonomic effects of low-dose glyceryl trinitrate used to test endothelium-independent vasodilation of the brachial artery

Smooth muscle function is explored by sublingual glyceryl trinitrate (GTN) administration to compare with endothelium-dependent vasodilation of the brachial artery by flow-mediated-dilation (FMD). This study compared the hemodynamic and autonomic effects of the two most often used GTN dosages.In 80 essential hypertensive patients (HT) and 60 normotensive subjects (NT), FMD of the brachial artery and endothelium-independent response to sublingual GTN (25 μg and 400 μg) were evaluated by high-resolution ultrasound and automated image analysis. In 10 HT, muscle sympathetic nerve activity (MSNA) was also assessed by microneurography.HT showed significantly (p < .01) lower FMD (5.5 ± 3.3%) compared to NT (6.9 ± 2.2%). The response to GTN 25 μg tended to be lower (HT:7.2 ± 3.3%; NT:7.9 ± 2.9%; p = .06), whereas response to GTN 400 μg was similar (HT:14.3 ± 4.8%, NT:14.5 ± 4.7%, p = ns). Blood pressure (BP) reduction induced by GTN 400 μg (systolic-BP:-3.2 ± 7.7 mm Hg, diastolic-BP:-4.7 ± 5.0 mm Hg) was greater (p < .001) compared to GTN 25 μg (systolic-BP:-0.7 ± 5.8 mm Hg, diastolic-BP:-0.7 ± 4.4 mm Hg). Changes in heart rate were also greater (+5.6 ± 6.4 bpm versus −0.2 ± 5.4 bpm, p < .001). This behaviour was similar in either NT or HT. MSNA was significantly increased by GTN 400 μg (31 ± 7bursts/min to 41 ± 6bursts/min, p < .001) but not by 25 μg (33 ± 9bursts/min to 37 ± 11bursts/min, p = .19).In conclusion, the administration of low-dose GTN allows exploring endothelium-independent vasodilation in FMD protocols, inducing only modest hemodynamic and sympathetic responses.

Blood Pressure, Body Composition, and Plasma Lipids Are Not Related to Indices of Vascular Health

Blood pressure, body composition and plasma lipoprotein concentrations are important markers for cardiovascular disease (CVD) risk. PURPOSE: To examine potential relationships between blood pressure, body composition, plasma lipoprotein concentrations and indices of vascular health as assessed with carotid-femoral pulse wave velocity (PWV) and flow mediated dilation (FMD). METHODS: Fourteen male subjects (age 32 ± 13 yrs, height 177.6 ± 6.6 cm, weight 83.3 ± 9.0 kg, lean mass 61.7 ± 6.3 kg, fat mass 18.4 ± 6.8 kg) volunteered for lab testing as part of a health assessment program, which included resting blood pressure, dual energy x-ray absorptiometry (DXA), FMD, PWV, and blood analysis. All testing was completed on the same day after an overnight fast. The vascular measures were taken via ultrasound, in a temperature controlled room with dim lighting. Each subject would lay supine for 10 minutes prior to the vascular measures. FMD was assessed in the brachial artery in response to a 5-minute distal occlusion. FMD results are given as a percent change from baseline. The PWV measure was assessed on the carotid and femoral arteries using 80% of the total distance between measure sites. PWV results are given in meter per second. All PWV and FMD measures were completed according to previously published procedures (Bortel, 2011; Corretti, 2002.). Body composition was assessed via DXA. Relationships among the data were analyzed with Pearson’s r (α = 0.05). RESULTS: No significant relationships were found with PWV or FMD and any of the CVD risk factors measured. The strongest correlations for PWV and FMD are listed in Table 1.Table 1CONCLUSION: Based on our results, accepted risk factors for CVD, including blood pressure, plasma lipoproteins, and body composition, are not related to indices of vascular health as assessed with PWV and FMD.

Vascular Function after Sauna Bathing in Healthy Older Adults

Repeated heat exposure by immersion in warm water improves vascular function in healthy young adults. This observation could explain the health benefits of sauna bathing reported in population‐based studies, in which regular sauna sessions lasting more than 19 minutes were shown to significantly decrease the risk of cardiovascular mortality. However, it is unknown if such sauna durations improve vascular function in older adults. The purpose of this study was to determine if 20 min of sauna bathing acutely improves vascular function in healthy older adults.Six older adults (4 women) without cardiovascular disease and risk factors (age range: 57–71 yrs) underwent a sauna bathing session consisting of 2 bouts of 10 min in a dry Finnish sauna (80°C) separated by 10 min of seated rest outside the sauna. Prior to and following sauna bathing, flow‐mediated dilation (FMD) of the brachial artery in response to reactive hyperemia induced by 5 min of forearm ischemia was assessed by Doppler ultrasound after a minimum of 30 min rest in the supine position in a quiet and thermoneutral environment. The percent change in artery diameter from baseline to peak was used as an index of macrovascular function, whereas post‐occlusive reactive hyperemia (PORH), estimated by the brachial artery flow area‐under‐the‐curve above baseline during the 3 min following ischemia, was used to evaluate microvascular function. Heart rate (HR), mean arterial pressure (MAP), oral temperature (Toral) and mean skin temperature (Tsk) were monitored throughout the study.Sauna caused an increase in HR (55 ± 8 to 86 ± 10 bpm, P&lt;0.01), mean Tsk (33.0 ± 0.5 to 40.7 ± 0.7°C, P&lt;0.01) and Toral (36.7 ± 0.3 to 37.4 ± 0.2°C, P=0.025) while changes in MAP were not statistically different (100 ± 8 to 90 ± 4 mmHg, p=0.137). At the time of FMD assessment, HR (53 ± 5 and 52 ± 5 bpm, P=0.56), MAP (92 ± 6 and 90 ± 5 mmHg, P=0.59) and Toral (36.8 ± 0.3 and 36.9 ± 0.1 °C, P=0.27) were similar before and after sauna bathing, whereas mean Tsk was elevated prior to the post‐sauna FMD assessment (34.3 ± 0.4 vs. 32.9 ± 0.5°C, P&lt;0.01). FMD was similar before and after sauna bathing (4.79 ± 2.21% vs. 4.86 ± 2.73%, P=0.93). PORH was also similar before and after sauna bathing (286 ± 198 vs. 380 ± 168 ml, P=0.18).These preliminary results indicate that macro‐ and microvascular functions are unaffected by two 10 min bouts of sauna bathing at 80°C in healthy older adults.Support or Funding InformationFunded by Fondation de l'Institut de cardiologie de Montréal and by Fonds de Recherche du Québec – Santé.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Enlarged Size and Impaired Elastic Properties of the Ascending Aorta are Associated with Endothelial Dysfunction and Elevated Plasma Matrix Metalloproteinase-2 Level in Patients with Bicuspid Aortic Valve

The aim of this study was to test whether enlarged size and impaired elastic properties of the ascending aorta are associated with impaired endothelial function and increases in plasma matrix metalloproteinase (MMP)-2 concentrations in patients with bicuspid aortic valve (BAV) without significant valvular dysfunction. The size and the elasticity of the ascending aorta and the flow-mediated vasodilation (FMD) in the brachial artery in response to hyperemia were evaluated with 2-D echocardiography and high-frequency linear ultrasound in 42 patients with BAV without significant valvular dysfunction and 30 age- and sex-matched healthy controls. In the BAV group, diastolic ascending aortic diameter (AoD) (32.1 ± 8.1 mm vs. 25.3 ± 3.6 mm, p < 0.001) and aortic stiffness index (8.0 ± 5.3 vs. 4.0 ± 1.8, p < 0.001) were significantly higher, and aortic strain (7.4 ± 3.6% vs. 11.1 ± 3.0%, p < 0.001) and aortic distensibility (7.4 ± 4.1 × 10−6cm2/dyn vs. 11.1 ± 4.3 × 10−6cm2/dyn, p < 0.001) were significantly lower than those in the control group. The BAV group also had lower FMD (6.5 ± 2.2% vs. 11.9 ± 2.7%, p < 0.001) and higher plasma MMP-2 levels (226.7 ± 55.0 ng/mL vs. 177.0 ± 45.3 ng/mL, p < 0.001) compared with the control group. In the BAV group, AoD, aortic strain, aortic stiffness index and aortic distensibility significantly correlated with FMD and MMP-2 (all p < 0.05). The multivariable linear regression analysis further indicated that FMD and MMP-2 were independently associated with AoD (β = −1.1, p = 0.005, and β = 0.09, p < 0.001, respectively). These findings suggest that enlarged size and impaired elastic properties of the ascending aorta are associated with endothelial dysfunction and elevated plasma MMP-2 level in patients with BAV without significant valvular dysfunction. FMD and plasma MMP-2 level are the significant and independent predictors of dilation of the ascending aorta in patients with BAV.