Endothelial function testing and cardiovascular disease: focus on peripheral arterial tonometry

Correlation between peripheral endothelial function, oxygen consumption and ventilatory efficiency in heart transplantation recipients

BACKGROUND

Endothelial dysfunction and peak oxygen uptake (VO2peak) are also predictors of increased risk of cardiovascular events in heart transplantation (HTx) recipients. The preservation of endothelial function may contribute to exercise tolerance.

OBJECTIVE

To investigate the correlation between peripheral endothelial function and exercise tolerance through VO2peak and ventilation to carbon dioxide production slope (VE / VCO2 slope) in HTx recipients.

METHODS

A pilot cross-sectional study was conducted with adult individuals aged 18-65 years, HTx ≥ six months after surgery, who had a stable medical condition and no changes over the last three months of immunosuppressive treatment. The patients underwent an assessment of endothelial function through PAT (EndoPAT-2000®) and performed a cardiopulmonary exercise test (CPET).

RESULTS

A total of 41% of the studied population presented endothelial dysfunction. The individuals were divided into two groups: the endothelial dysfunction (GED; n=9) group and the normal endothelial function (GNEF; n=13) group according to the logarithm of the reactive hyperemia index (LnRHI). There was a positive and moderate correlation between the LnRHI and VO2 peak (r=0.659, p=0.013) and a negative and moderate correlation between the LnRHI and VE/VCO2 slope (r= -0.686, p= 0.009) in the GNEF. However, no significant correlations were found in the GED.

CONCLUSION

The results showed that the preservation of peripheral endothelial function is significantly correlated with an increase in exercise tolerance in individuals after HTx. These findings bring important considerations for cardiovascular risk prevention and emphasize that therapeutic strategies with physical training programs must be implemented early.

Acute effects of cigarette smoke on Endothelial Nitric Oxide synthase, vascular cell adhesion molecule 1 and aortic intima media thickness

Background. Cigarette smoking could induce endothelial dysfunction and the increase of circulating markers of inflammation by activation of monocytes. This can lead to increased intima media thickness (IMT) of entire blood vessels and result in acceleration of the atherosclerosis process. However, to our knowledge, little is known about the role of cigarette smoking in this atherosclerotic inflammatory process. The aim of this study is to explore the link between cigarette smoking and its effect on endothelial nitric oxide synthase (e-NOS) and vascular cell adhesion molecule 1 (VCAM-1). Methods. An experimental study with a post-test only controlled group design was used. We used 18 Wistar rats ( Rattus norvegicus) randomly subdivided into two groups: group K (-) were not exposed to tobacco smoke, whereas group K (+) were exposed to smoke equivalent of more than 40 cigarettes for 28 days daily. After 28 days, samples were analyzed for e-NOS, VCAM-1 and aortic IMT. Results . Our results indicate that tobacco smoke can enhance the expression of VCAM-1 on rat cardiac vascular endothelial cells, resulting in a decreased expression of e-NOS level and increase of aortic IMT. Linear regression model found that eNOS level negatively correlated wiith aortic IMT ( r 2 = 0.584, β = -0.764, p < 0.001), whereas VCAM-1 expression did not correlate with aortic IMT ( r 2 = 0.197, p = 0.065). Conclusion. Low e-NOS level and high VCAM-1 level observed after cigarette smoke exposure which may increase aortic IMT.

Effect of heat-moisture treated brown rice crackers on postprandial flow-mediated dilation in adults with mild endothelial dysfunction

Background

Endothelial dysfunction is an early pathophysiological feature and independent predictor of a poor prognosis in most forms of cardiovascular disease. We evaluated the effect of brown rice crackers (BR-C) on endothelial function.

Methods

Effect of heat-moisture treated (HMT) -BR-C on postprandial flow-mediated dilation (FMD) in adults with mild endothelial dysfunction was compared with that of BR-C and white rice crackers (WR-C) in 12 adults with mild endothelial dysfunction (less than 7.0% of FMD) by a randomized, single-blind, three-treatment three-period crossover trial (UMIN 000034898). Since we considered that the FMD increase was associated with the treatment of HMT-BR-C, we examined the effect of three possible factors: postprandial glucose levels, polyphenol content, and polyphenol release from the food matrix.

Results

Mean pre-intake baseline FMD values of HMT-BR-C, BR-C, and WR-C were 4.9%, 5.1%, and 4.9%, respectively, and those values 1 h post-intake were 6.3%, 5.1%, and 4.8%, respectively. There was no difference in intergroup comparisons of FMD using Dunnett's multiple comparison test. There was a significant increase in FMD only in HMT-BR-C in intragroup comparisons (P = 0.042 by paired-t test). In comparison with BR-C, no significant difference was noted in the postprandial glucose level nor in the content of total polyphenols and ferulic acid derivatives in HMT-BR-C. However, the 70% ethanol extracted from HMT-BR-C contained a significantly larger amount of free and bound ferulic acids than from BR-C.

Conclusion

HMT-BR-C intake increased the postprandial FMD response.

Endothelial Function and Arterial Stiffness Should Be Measured to Comprehensively Assess Obstructive Sleep Apnea in Clinical Practice

Objective: An effective clinical tool to assess endothelial function and arterial stiffness in patients with obstructive sleep apnea (OSA) is lacking. This study evaluated the clinical significance of subclinical markers for OSA management in males without serious complications.

Patients/Methods: Males without serious complications were consecutively recruited. Clinical data, biomarker tests, reactive hyperemia index (RHI), and augmentation index at 75 beats/min (AIx75) measured by peripheral arterial tonometry were collected. An apnea hypopnea index (AHI) cutoff of ≥15 events/h divided the patients into two groups.

Results: Of the 75 subjects, 42 had an AHI ≥15 events/h. Patients with an AHI ≥15 events/h had higher high-sensitivity C-reactive protein, tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor, and AIx75 values than the control group but no statistical difference in RHI was observed. After controlling for confounders, TNF-α was negatively correlated with the average oxygen saturation (r = −0.258, P = 0.043). RHI was correlated with the rapid eye movement (REM) stage percentage (r = 0.306, P = 0.016) but not with AHI (P > 0.05). AIx75 was positively correlated with the arousal index (r = 0.289, P = 0.023) but not with AHI (r = 0.248, P = 0.052).

Conclusions: In males with OSA without severe complications, TNF-α and AIx75 are independently related to OSA. The role of RHI in OSA management requires further elucidation. These markers combined can comprehensively evaluate OSA patients to provide more evidence for the primary prevention of coronary heart disease and treatment response assessment.

Effects of Hydroxychloroquine on endOthelial function in eLDerly with sleep apnea (HOLD): study protocol for a randomized clinical trial

BACKGROUND

Sleep apnea and coronary artery disease are prevalent and relevant diseases. The mechanism by which sleep apnea leads to coronary artery disease remains unclear. Intermittent hypoxia, caused by sleep apnea, leads to inflammation and consequent endothelial dysfunction. Endothelial dysfunction precedes the development of atherosclerotic disease and the occurrence of cardiovascular events. Agents that potentially act to improve endothelial function can help prevent cardiovascular events. Patients using immunomodulators due to rheumatic diseases have a lower prevalence of cardiovascular diseases. However, the potential cardioprotective effect of these drugs in patients without autoimmune diseases is not clear. Hydroxychloroquine (HCQ) is an immunomodulator used to treat rheumatoid arthritis and systemic lupus erythematosus. In addition to its anti-inflammatory properties, HCQ reduces cholesterol and blood glucose levels and has antithrombotic effects. The drug is inexpensive and widely available. Adverse effects of HCQ are rare and occur more frequently with high doses.

OBJECTIVE

In this randomized clinical trial, the effect of HCQ treatment on endothelial function will be tested in seniors with sleep apnea.

METHODS

We will recruit participants over the age of 65 and with moderate-severe sleep apnea from an ongoing cohort. We chose to use this sample already evaluated for sleep apnea for reasons of convenience, but also because the elderly with sleep apnea are vulnerable to heart disease. Endothelial function will be assessed by examining flow-mediated dilation of the brachial artery, the gold standard method, considered an independent predictor of cardiovascular events in the general population and by peripheral arterial tonometry, the most recent and most easily obtained method. Hydroxychloroquine will be used at a dose of 400 mg/daily for 8 weeks.

DISCUSSION

Our study aims to obtain evidence, albeit preliminary, of the efficacy of hydroxychloroquine in improving endothelial function and reducing cardiovascular risk markers. If the improvement occurs, we plan to design a randomized multicenter clinical trial to confirm the findings.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04161339 . Registered on November 2019.

Preventive effect of Nigella sativa on M1/M2 ratio, reducing risk of endothelial dysfunction in cigarette smoked Wistars

Background: Smoking is one of the top three causes of cardiovascular disease (CVD). Natural antioxidants including black cumin ( Nigella sativa) may inhibit the pathogenesis of initial process of atherosclerosis. The aim of this study was to determine the effect of black cumin (Nigella sativa) in preventing endothelial dysfunction mainly through macrophage M1/M2 inflammatory response in cigarette smoked male Wistars. Methods: In total, 50 Wistar rats were randomly allocated to five experimental groups: two control groups, namely no intervention (K-) and exposure to smoke of 40 cigarettes each day (K+); and three treatment groups: rats given a dose of 0.3 g (P1), 0.6 g (P2) or 1.2 g (P3) black cumin per kilograms bodyweight/ day, respectively, and exposed to smoke of 40 cigarettes each day. After 28 days of cigarette smoke exposure, macrophage M1/M2 ratio was evaluated by counting total M1 and M2 in ten microscope field of view. Data were analysed by Mann-Whitney test. Results: The M1 / ​​M2 ratio on K (-) was 0.9 7 ± 0.9 8 (<1) which means M2 was dominant, while the M1 / ​​M2 ratio on K (+) was of 4.97 ± 3.42 (> 1) which means M1 dominant. There was no significant difference in the number of M1 count in treatment groups P1, P2, P3 (p value = 0.996; 0.170; 0.884, respectively) when compared with K+. Additionally, P2 group has the lower M1 number with the highest significance value when compared to K+. The number of M1 counts on P1 did not differ significantly when compared to P2 with p = 0.121 and P3 with p = 0.936. Conclusions: In sum, ethanol extract of black cumin prevents endothelial dysfunction by inhibiting increase in macrophages M1 / M2 ratio in rats  Wistar exposed to sub-chronic cigarette smoke.

Reactive hyperemia correlates with the presence of sepsis and glycocalyx degradation in the intensive care unit: a prospective cohort study

Objective

To investigate whether reactive hyperemia measured by peripheral arterial tonometry correlates with markers of endothelial dysfunction and may be used to identify sepsis in critical illness.

Methods

A prospective study was performed using a cohort of critically ill patients. Endothelial dysfunction was assessed on admission by quantifying reactive hyperemia-peripheral arterial tonometry and plasma levels of endothelin-1, soluble E-selectin, endocan and syndecan-1. Septic patients were compared to patients without evidence of infection.

Results

Fifty-eight septic patients were compared to 28 controls. The natural logarithm of reactive hyperemia-peripheral arterial tonometry was negatively correlated with cardiovascular comorbidities, disease severity and plasma levels of soluble E-selectin (p = 0.024) and syndecan-1 (p < 0.001). The natural logarithm of reactive hyperemia-peripheral arterial tonometry was lower in septic patients than in controls (0.53 ± 0.48 versus 0.69 ± 0.42, respectively). When adjusted for age, the multivariable model predicted that each 0.1-unit decrease in natural logarithm of reactive hyperemia-peripheral arterial tonometry increased the odds for infection by 14.6%. m.

Conclusion

Reactive hyperemia-peripheral arterial tonometry is closely related to soluble E-selectin and syndecan-1, suggesting an association between endothelial activation, glycocalyx degradation and vascular reactivity. Reactive hyperemia-peripheral arterial tonometry appears to be compromised in critically ill patients, especially those with sepsis.

The treatment of mild OSA with CPAP or mandibular advancement device and the effect on blood pressure and endothelial function after one year of treatment

STUDY OBJECTIVES

To evaluate and compare the effects of continuous positive airway pressure (CPAP), use of a mandibular advancement device (MAD), and no treatment on 24-hour ambulatory blood pressure monitoring and peripheral arterial tonometry at 6 and 12 months follow-up in individuals with mild obstructive sleep apnea (OSA), and in a subgroup who had an apnea-hypopnea index of < 5 events/h and adherence of ≥ 4 hours per night (effective-treatment subgroups).

METHODS

The inclusion criteria were individuals with mild obstructive sleep apnea, any sex, age between 18 and 65 years, and a body mass index of ≤ 35 kg/m². Patients were randomized into CPAP, MAD, and no-treatment groups. The evaluations included physical examination, full polysomnography, 24-hour ambulatory blood pressure monitoring, and peripheral arterial tonometry at baseline and after 6 and 12 months. A generalized linear mixed model was used for comparisons.

RESULTS

The CPAP and MAD groups had lower apnea-hypopnea indexes than the control group at 6 and 12 months, and the CPAP group had higher blood oxygen levels (SpO₂) than the MAD group. The MAD group had more hours of treatment per night and better adaptation to treatment than the CPAP group (MAD: 5.7 ± 2.7 h/night; CPAP: 3.8 ± 3.4 h/night; MAD: 16% did not adapt; CPAP: 42% did not adapt). No differences were found in the total sample and effective treatment in relation to peripheral arterial tonometry or 24-hour ambulatory blood pressure monitoring outcomes.

CONCLUSIONS

Treatment of mild obstructive sleep apnea with CPAP or MAD did not improve blood pressure or endothelial function after 1 year, even in patients with effective treatment.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Continuous Positive Airway Pressure and Oral Appliances Treatments in Mild Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT01461486; Identifier: NCT01461486.

Exposure to household air pollutants and endothelial dysfunction in rural Bangladesh: A cross-sectional study

More than one third of world's population use biomass fuel for cooking that has been linked to an array of adverse health hazards including cardiovascular mortality and morbidity. As part of Bangladesh Global Environmental and Occupational Health (GEO Health) project, we assessed whether household air pollution (HAP) was associated with dysfunction in microvascular circulation (measured by reactive hyperemia index [RHI]).

METHODS

We measured exposure to HAP (particulate matter [PM2.5], carbon monoxide [CO], and black carbon [BC]) for 48 hours of 200 healthy nonsmoker adult females who used biomass fuel for cooking. Exposure to PM2.5 and BC were measured using personal monitor, RTI MicroPEM (RTI International, NC) with an internal filter that had been both pre- and post-weighed to capture the deposited pollutants concentration. Lascar CO logger was used to measure CO. Endothelial function was measured by forearm blood flow dilatation response to brachial artery occlusion using RHI based on peripheral artery tonometry. A low RHI score (<1.67) indicates impaired endothelial function.

RESULTS

Average 48 hours personal exposure to PM2.5 and BC were 144.15 μg/m3 (SD 61.26) and 6.35 μg/m3 (SD 2.18), respectively. Interquartile range for CO was 0.73 ppm (0.62-1.35 ppm). Mean logarithm of RHI (LnRHI) was 0.57 in current data. No statistically significant association was observed for LnRHI with PM2.5 (odds ratio [OR] = 0.97; 95% confidence interval [CI] = 0.92, 1.01; P = 0.16), BC (OR = 0.85; 95% CI = 0.72, 1.01; P = 0.07), and CO (OR = 0.89; 95% CI = 0.64, 1.25; P = 0.53) after adjusting for potential covariates.

CONCLUSIONS

In conclusion, HAP was not associated with endothelial dysfunction among nonsmoking females in rural Bangladesh who used biomass fuel for cooking for years.

Effect of exercise on endothelial function in heart transplant recipients: systematic review and meta-analysis

Endothelial dysfunction is associated with increased cardiovascular risk and death in heart transplant recipients (HTx). Although the measurement of peripheral endothelial function is considered a significant predictor of cardiovascular events in several populations, few studies have investigated this outcome after therapeutic strategies, including different exercise types, duration, and intensity. This systematic review and meta-analysis aimed to investigate the effects of continuous moderate exercise (CON) or high-intensity interval training (HIIT) to improve endothelial function (EF) in HTx. The search was conducted in Cochrane Central Registry of Controlled Trials (CENTRAL), MEDLINE (via PubMed), Web of Science and Scopus/Elsevier, CINAHL/Ebsco, Physiotherapy Evidence Database (PEDro), LILACS/BIREME, and SciELO databases. Quality of the evidence was assessed using the Grading of Recommendations Assessment Development and Evaluation (GRADE). The search strategy retrieved 5192 titles. A total of four articles met the inclusion criteria and were included for the qualitative analysis. Meta-analysis showed that exercises improved EF ([mean difference-MD] 3.48 95% CI - 0.29 to 7.25, p = 0.007) when compared with the control. However, there was a poor quality of evidence to demonstrate that CON or HIIT is better than usual care to improve EF. Exercise training provides benefits to patients, but the poor quality of evidence does not allow us to state that exercise is related to endothelial function improvement in HTx.

Small Fibre Neuropathy Is Associated With Impaired Vascular Endothelial Function in Patients With Type 2 Diabetes

Diabetic polyneuropathy (DPN) and endothelial dysfunction are prevalent complications of diabetes mellitus. Currently, there are two non-invasive markers for endothelial dysfunction: flow-mediated dilation and reactive hyperaemia peripheral arterial tonometry (RH-PAT). However, the relationship between diabetic small fibre neuropathy and macroangiopathy remains obscure thus far. Corneal confocal microscopy (CCM) has emerged as a new diagnostic modality to assess DPN, especially of small fibre. To clarify the relationship between diabetic small fibre neuropathy and vascular dysfunction, we aimed to determine the functions of peripheral nerves and blood vessels through clinical tests such as nerve conduction study, coefficient of variation in the R-R interval, CCM, and RH-PAT in 82 patients with type 2 diabetes. Forty healthy control subjects were also included to study corneal nerve parameters. Correlational and multiple linear regression analyses were performed to determine the associations between neuropathy indices and markers for vascular functions. The results revealed that patients with type 2 diabetes had significantly lower values for most variables of CCM than healthy control subjects. RH-PAT solely remained as an explanatory variable significant in multiple regression analysis for several CCM parameters and vice versa. Other vascular markers had no significant multiple regression with any CCM parameters. In conclusion, endothelial dysfunction as revealed by impaired RH-PAT was significantly associated with CCM parameters in patients with type 2 diabetes. This association may indicate that small fibre neuropathy results from impaired endothelial dysfunction in type 2 diabetes. CCM parameters may be considered surrogate markers of autonomic nerve damage, which is related to diabetic endothelial dysfunction. This study is the first to report the relationship between corneal nerve parameter as small fibre neuropathy in patients with type 2 diabetes and RH-PAT as a marker of endothelial dysfunction.

Characterization of Cardiac, Vascular, and Metabolic Changes in Young Childhood Cancer Survivors

Background: Childhood cancer survivors (CCS) are at an increased risk for cardiovascular diseases (CVD). It was the primary aim of this study to determine different measures of cardiac, carotid, lipid, and apolipoprotein status in young adult CCS and in healthy controls. Methods: Cardiac and common carotid artery (CCA) structure and function were measured by ultrasonography. Lipids and apolipoproteins were measured in the blood. Peripheral arterial endothelial vasomotor function was assessed by measuring digital reactive hyperemia index (PAT-RHI) using the Endo-PAT 2000. Results: Fifty-three CCS (20-30 years, 35 men) and 53 sex-matched controls were studied. The CCS cohort was divided by the median dose of anthracyclines into a low anthracycline dose (LAD) group (50-197 mg/m², n = 26) and a high anthracycline dose (HAD) group (200-486 mg/m², n = 27). Carotid distensibility index (DI) and endothelial function determined by PAT-RHI were both lower in the CCS groups compared with controls (p < 0.05 and p = 0.02). There was no difference in carotid intima media thickness. Atherogenic apolipoprotein-B (Apo-B) and the ratio between Apo-B and Apoliprotein-A1 (Apo-A1) were higher in the HAD group compared with controls (p < 0.01). Apo-B/Apo-A1-ratio was over reference limit in 29.6% of the HAD group, in 15.4% of LAD group, and in 7.5% of controls (p = 0.03). Measured lipid markers (low density lipoprotein and total cholesterol and triglycerides) were higher in both CCS groups compared with controls (p < 0.05). Systolic and diastolic function were measurably decreased in the HAD group, as evidenced by lower EF (p < 0.001) and lower é-wave (p < 0.005) compared with controls. CCA DI correlated with Apo-B/Apo-A1-ratio and Apo-A1. Follow-up time after treatment correlated with decreased left ventricular ejection fraction (p = 0.001). Conclusion: Young asymptomatic CCS exhibit cardiac, vascular, lipid, and apolipoprotein changes that could account for increased risk for CVD later in life. These findings emphasize the importance of cardiometabolic monitoring even in young CCS.

The Relation Between Common Carotid Artery Diameter and Central Venous Pressure for Assessment of Intravascular Fluid Status after Major Surgeries; an Observational Study

Objectives

The current study aimed to find the relation between the changes in the common carotid artery (CCA) diameter and the central venous pressure (CVP) in response to a fluid challenge in spontaneously breathing adult patients.

Methods

This study included 65 adult patients aged 20 - 60 years who were admitted to the surgical ICU. The CCA diameter and CVP were measured before and after fluid challenge, and the percentage of increase in the CCA diameter and CVP were calculated. The correlation was assessed between changes in the CVP and CCA diameter.

Results

The CCA diameter before fluid administration had a significant strong positive correlation to the CVP (r = 0.8, P value < 0.001); the increase in the CCA diameter after fluid administration had a significant moderate positive correlation with the increase in the CVP (r = 0.4, P value < 0.001). The percentage of increase in CCA diameters was positively correlated to the percentage of increase in CVP (r = 0.589, P value = 0.001) following fluid administration. However, the Receiver Operating Characteristic (ROC) analysis was an invalid test (area under curve 0.513, P value = 0.885).

Conclusions

After major surgeries, the change in the CCA diameter was positively correlated with the change in the CVP values in response to fluid administration in the spontaneously breathing adult patients, but the cut-off limit cannot be reached.

Association of endothelial dysfunction with incident prediabetes, type 2 diabetes and related traits: the KORA F4/FF4 study

INTRODUCTION

Peripheral arterial tonometry (PAT) is an operator-independent and non-invasive measurement method to assess microvascular endothelial function in the fingertips. PAT-derived measures of endothelial function were associated with type 2 diabetes in cross-sectional studies. However, longitudinal studies are lacking. The study aims to investigate the association of two PAT-derived endothelial function parameters reactive hyperemia index (RHI) and mean baseline amplitude (MBA) with follow-up glucose and insulin parameters and the development of (pre)diabetes and type 2 diabetes.

RESEARCH DESIGN AND METHODS

The study included 673 participants initially without diabetes (328 men and 345 women) aged 52-71 years from the prospective population-based Cooperative Health Research in the Region of Augsburg F4/FF4 cohort study conducted in Southern Germany (baseline examination F4: 2006-2008; follow-up FF4: 2013-2014). An oral glucose tolerance test was performed at baseline and follow-up to define type 2 diabetes, prediabetes, fasting glucose, fasting insulin, 2-hour glucose, homeostasis model assessment of insulin resistance (HOMA-IR), homeostasis model assessment of beta-cell function and hemoglobin A1c.

RESULTS

In multivariable adjusted logistic/linear regression models, a 1 SD increase in baseline RHI was inversely associated with incident type 2 diabetes (OR 0.69 (95% CI 0.48 to 0.97)) as well as with fasting insulin (β -0.069 (95% CI -0.131 to -0.007)) and HOMA-IR (β -0.072 (95% CI -0.133 to -0.010)) at follow-up in participants with initial normoglycemia. A 1 SD increase in baseline MBA was positively associated with incident (pre)diabetes (OR 1.62 (95% CI 1.25 to 2.11)) and fasting glucose (β 0.096 (95% CI 0.047 to 0.146)) at follow-up in participants with initial normoglycemia.

CONCLUSIONS

Microvascular endothelial dysfunction seems to be involved in the development of early derangements in glucose metabolism and insulin resistance and could thereby trigger the development of prediabetes and type 2 diabetes.

A new peripheral endothelial function measurement improves prediction of symptomatic coronary artery disease

Objective

This study aimed to determine whether a peripheral artery volume (PAV) test can improve the predictive value of the age-adjusted Framingham risk score (AFRS) for coronary artery disease (CAD) in symptomatic patients.

Methods

A total of 317 consecutive patients who were referred for coronary angiography were prospectively enrolled. Before cardiac catheterization, a PAV test was performed to measure changes in pulsatile blood flow volume following reactive hyperemia.

Results

PAV was significantly lower in patients with CAD than in those without CAD (1.21 ± 0.32 vs. 1.50 ± 0.45). Multivariate logistic regression analysis showed that PAV and the AFRS were independent predictors of CAD. Pairwise comparison of receiver operating characteristic curves showed that the predictive power for CAD increased when PAV was incorporated into the AFRS (area under the curve: from 0.76 to 0.80). The net reclassification index was also improved when PAV was added to the AFRS (0.65, 95% confidence interval: 0.44–0.85).

Conclusions

Digital endothelial function measurement is an independent predictor of CAD. PAV is potentially useful for identifying patients at high risk for CAD.

Acute Exenatide Therapy Attenuates Postprandial Vasodilation in Humans with Prediabetes: A Randomized Controlled Trial

Background: The state of prediabetes comprises atherosclerotic changes leading to decreased vascular function in humans. This study examined the effects on incretin mimetics on vascular physiology in the prediabetic postprandial state. Methods: Fifteen obese adults with prediabetes participated in a randomized, crossover, double-blinded trial comparing the postprandial effects of exenatide, saxagliptin, and placebo on peripheral vasodilation. All studies utilized a standardized high-fat meal. Resting and peak forearm blood flow (FBF) were measured via strain gauge venous occlusion plethysmography, and makers of vascular dysfunction were measured in plasma. Results: Exenatide attenuated resting FBF at 3 hr (P = 0.003) and 6 hr (P = 0.056) postmeal, compared to placebo. Nonsignificant reductions in resting FBF were observed between saxagliptin and placebo at the same time points. No group differences were observed for peak FBF, plasma nitrotyrosine, and plasma 8-iso-prostaglandin F2alpha. A transient increase in plasma triglyceride was abated in the exenatide group, when compared to saxagliptin and placebo groups. Only exenatide group showed no significant upsurge in plasma insulin. Plasma-free fatty acids significantly declined in all three groups, although less markedly for exenatide. Postmeal glucose increased at 2 hr with placebo and saxagliptin, but simultaneously decreased with exenatide. Conclusions: Acute treatment with exenatide blunted the postprandial vasodilatory effect of a high-fat meal in prediabetes. Exenatide's acute effects derived primarily from multiple endothelium-independent processes. Trial Registration Number: NCT02104739.

A Systematic Review of Vascular Structure and Function in Pre-eclampsia: Non-invasive Assessment and Mechanistic Links

Hypertensive disorders of pregnancy, such as pre-eclampsia, are known to be independently associated with the development of premature cardiovascular disease (CVD) in women. In pre-eclampsia, the placenta secretes excess anti-angiogenic factors into the maternal circulation, leading to widespread endothelial damage, and inflammation. This endothelial damage is evidenced to persist beyond the acute illness. However, whether it is permanent and responsible for the elevated rates of premature CVD seen in this at-risk group remains unclear. A systematic review of the available literature with respect to vascular structure and function prior to, during and after a pregnancy complicated by pre-eclampsia was performed. Studies non-invasively assessing vascular structure using carotid intima-media thickness (CIMT), retinal microvasculature caliber, CT coronary angiogram, or coronary calcium scores were included. Vascular function was assessed using brachial flow-mediated dilation (FMD), pulse wave analysis (PWA), and peripheral arterial tonometry (PAT). In total 59 articles were included (13 CIMT, 5 CTCA/Ca score, five retinal microvasculature, 27 FMD, 7 PAT, and 14 PWV/PWA), consisting of prospective and retrospective cohort, and case-control studies. Change in vascular structure was evidenced with significant increases in CIMT by 73-180 μm greater than that of non-affected women. This is tempered by other studies reporting resolution of structural changes postpartum, highlighting the need for further research. Accelerated coronary calcification and plaque deposition was identified, with greater rates of increased calcium scores and subclinical coronary artery disease shown by CTCA in women with a history of pre-eclampsia at 30 years postpartum. Impaired endothelial function was consistently reported prior to, during and immediately after pregnancy as evidenced by differences in FMD of 1.7-12.2% less than non-affected women, an increase in PWV by 13.2-26%, and reduced retinal microvascular caliber and arterial elasticity indices. The evidence was less conclusive for the persistence of long-term endothelial dysfunction. Understanding the underlying mechanistic links between pre-eclampsia and CVD is a key step to identifying targeted therapies aimed at "repairing the endothelium" and attenuating risk. This review has highlighted the need for a greater understanding of vascular structure and function following pre-eclampsia through high quality studies with large sample sizes, particularly in the longer postpartum period when clinical CVD disease starts to manifest.

A Systematic Review of Vascular Structure and Function in Pre-eclampsia: Non-invasive Assessment and Mechanistic Links

Hypertensive disorders of pregnancy, such as pre-eclampsia, are known to be independently associated with the development of premature cardiovascular disease (CVD) in women. In pre-eclampsia, the placenta secretes excess anti-angiogenic factors into the maternal circulation, leading to widespread endothelial damage, and inflammation. This endothelial damage is evidenced to persist beyond the acute illness. However, whether it is permanent and responsible for the elevated rates of premature CVD seen in this at-risk group remains unclear. A systematic review of the available literature with respect to vascular structure and function prior to, during and after a pregnancy complicated by pre-eclampsia was performed. Studies non-invasively assessing vascular structure using carotid intima-media thickness (CIMT), retinal microvasculature caliber, CT coronary angiogram, or coronary calcium scores were included. Vascular function was assessed using brachial flow-mediated dilation (FMD), pulse wave analysis (PWA), and peripheral arterial tonometry (PAT). In total 59 articles were included (13 CIMT, 5 CTCA/Ca score, five retinal microvasculature, 27 FMD, 7 PAT, and 14 PWV/PWA), consisting of prospective and retrospective cohort, and case-control studies. Change in vascular structure was evidenced with significant increases in CIMT by 73–180 μm greater than that of non-affected women. This is tempered by other studies reporting resolution of structural changes postpartum, highlighting the need for further research. Accelerated coronary calcification and plaque deposition was identified, with greater rates of increased calcium scores and subclinical coronary artery disease shown by CTCA in women with a history of pre-eclampsia at 30 years postpartum. Impaired endothelial function was consistently reported prior to, during and immediately after pregnancy as evidenced by differences in FMD of 1.7–12.2% less than non-affected women, an increase in PWV by 13.2–26%, and reduced retinal microvascular caliber and arterial elasticity indices. The evidence was less conclusive for the persistence of long-term endothelial dysfunction. Understanding the underlying mechanistic links between pre-eclampsia and CVD is a key step to identifying targeted therapies aimed at “repairing the endothelium” and attenuating risk. This review has highlighted the need for a greater understanding of vascular structure and function following pre-eclampsia through high quality studies with large sample sizes, particularly in the longer postpartum period when clinical CVD disease starts to manifest.

Endothelial Function is improved by Inducing Microbial Polyamine Production in the Gut: A Randomized Placebo-Controlled Trial

Recently, it was demonstrated that spermidine-induced autophagy reduces the risk of cardiovascular disease in mice. Intestinal bacteria are a major source of polyamines, including spermidine. We previously reported that the intake of both Bifidobacterium animalis subsp. lactis (Bifal) and arginine (Arg) increases the production of putrescine, a spermidine precursor, in the gut. Here, we investigated the effects of Bifal and Arg consumption on endothelial function in healthy subjects. Healthy individuals with body mass index (BMI) near the maximum value in the “healthy” range (BMI: 25) (n = 44) were provided normal yogurt containing Bifal and Arg (Bifal + Arg YG) or placebo (normal yogurt) for 12 weeks in this randomized, double-blinded, placebo-controlled, parallel-group comparative study. The reactive hyperemia index (RHI), the primary outcome, was measured using endo-peripheral arterial tone (EndoPAT). The change in RHI from week 0 to 12 in the Bifal + Arg YG group was significantly higher than that in the placebo group, indicating that Bifal + Arg YG intake improved endothelial function. At week 12, the concentrations of fecal putrescine and serum putrescine and spermidine in the Bifal + Arg YG group were significantly higher than those in the placebo group. This study suggests that consuming Bifal + Arg YG prevents or reduces the risk of atherosclerosis.

Rethinking Endothelial Dysfunction as a Crucial Target in Fighting Heart Failure

Endothelial dysfunction is characterized by nitric oxide dysregulation and an altered redox state. Oxidative stress and inflammatory markers prevail, thus promoting atherogenesis and hypertension, important risk factors for the development and progression of heart failure. There has been a reemerging interest in the role that endothelial dysfunction plays in the failing circulation. Accordingly, patients with heart failure are being clinically assessed for endothelial dysfunction via various methods, including flow-mediated vasodilation, peripheral arterial tonometry, quantification of circulating endothelial progenitor cells, and early and late endothelial progenitor cell outgrowth measurements. Although the mechanisms underlying endothelial dysfunction are intimately related to cardiovascular disease and heart failure, it remains unclear whether targeting endothelial dysfunction is a feasible strategy for ameliorating heart failure progression. This review focuses on the pathophysiology of endothelial dysfunction, the mechanisms linking endothelial dysfunction and heart failure, and the various diagnostic methods currently used to measure endothelial function, ultimately highlighting the therapeutic implications of targeting endothelial dysfunction for the treatment of heart failure.

A new method for the assessment of endothelial function with peripheral arterial volume

Background

Currently, many methodological approaches have been developed to assess peripheral endothelial function. However, a development of the noninvasive and automated technique for routinely assessing endothelial function is still required. We evaluated the potential value of a new method to measure peripheral endothelial function with reactive hyperemia peripheral arterial volume (RH-PAV) in patients with chest pain.

Methods

We used a novel oximeter-like probe to detect the peripheral arterial volume (PAV) of the finger and compared it with brachial flow-mediated dilation (FMD) performed in 93 consecutive patients with chest pain. The RH-PAV index was defined as the ratio of the digital pulse volume during reactive hyperemia relative to the baseline.

Results

Ninety-three patients (53 men, 58 ± 5 years) completed the study, and 53 patients demonstrated coronary artery disease (CAD) following scheduled coronary angiography. There was a moderate linear relationship between PAV and FMD (r = 0.69, p < 0.01). Similar to FMD, PAV was more impaired in patients who have more cardiovascular risk factors (CRFs). The subjects with CAD had lower PAV and FMD, compared with those without CAD (1.05 ± 0.23 VS. 1.41 ± 0.37, p < 0.01; 6.7% ± 2.9% VS. 10.4% ± 2.9%, p < 0.01, respectively), and the relationships between FMD and PAV were also significant in both CAD (r = 0.54, p < 0.01) and non-CAD (r = 0.62, p < 0.01) patients.

Conclusions

Endothelial function of digital artery assessed with the novel PAV method demonstrated a profile similar to that of brachial artery measured with FMD. The hyperemia PAV was decreased by factors which were considered to impair endothelial function, suggesting that PAV has the potential to be a novel method to study endothelial function.

Effects of a liquefied petroleum gas stove intervention on pollutant exposure and adult cardiopulmonary outcomes (CHAP): study protocol for a randomized controlled trial

BACKGROUND

Biomass fuel smoke is a leading risk factor for the burden of disease worldwide. International campaigns are promoting the widespread adoption of liquefied petroleum gas (LPG) in resource-limited settings. However, it is unclear if the introduction and use of LPG stoves, in settings where biomass fuels are used daily, reduces pollution concentration exposure, improves health outcomes, or how cultural and social barriers influence the exclusive adoption of LPG stoves.

METHODS

We will conduct a randomized controlled, field intervention trial of LPG stoves and fuel distribution in rural Puno, Peru, in which we will enroll 180 female participants aged 25-64 years and follow them for 2 years. After enrollment, we will collect information on sociodemographic characteristics, household characteristics, and cooking practices. During the first year of the study, LPG stoves and fuel tanks will be delivered to the homes of 90 intervention participants. During the second year, participants in the intervention arm will keep their LPG stoves, but the gas supply will stop. Control participants will receive LPG stoves and vouchers to obtain free fuel from distributors at the beginning of the second year, but gas will not be delivered. Starting at baseline, we will collect longitudinal measurements of respiratory symptoms, pulmonary function, blood pressure, endothelial function, carotid artery intima-media thickness, 24-h dietary recalls, exhaled carbon monoxide, quality-of-life indicators, and stove-use behaviors. Environmental exposure assessments will occur six times over the 2-year follow-up period, consisting of 48-h personal exposure and kitchen concentration measurements of fine particulate matter and carbon monoxide, and 48-h kitchen concentrations of nitrogen dioxide for a subset of 100 participants.

DISCUSSION

Findings from this study will allow us to better understand behavioral patterns, environmental exposures, and cardiovascular and pulmonary outcomes resulting from the adoption of LPG stoves. If this trial indicates that LPG stoves are a feasible and effective way to reduce household air pollution and improve health, it will provide important information to support widespread adoption of LPG fuel as a strategy to reduce the global burden of disease.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02994680 , Cardiopulmonary Outcomes and Household Air Pollution (CHAP) Trial. Registered on 28 November 2016.

Endothelial Function Is Associated with White Matter Microstructure and Executive Function in Older Adults

Age-related declines in endothelial function can lead to cognitive decline. However, little is known about the relationships between endothelial function and specific neurocognitive functions. This study explored the relationship between measures of endothelial function (reactive hyperemia index; RHI), white matter (WM) health (fractional anisotropy, FA, and WM hyperintensity volume, WMH), and executive function (Trail Making Test (TMT); Trail B - Trail A). Participants were 36 older adults between the ages of 59 and 69 (mean age = 63.89 years, SD = 2.94). WMH volume showed no relationship with RHI or executive function. However, there was a positive relationship between RHI and FA in the genu and body of the corpus callosum. In addition, higher RHI and FA were each associated with better executive task performance. Tractography was used to localize the WM tracts associated with RHI to specific portions of cortex. Results indicated that the RHI-FA relationship observed in the corpus callosum primarily involved tracts interconnecting frontal regions, including the superior frontal gyrus (SFG) and frontopolar cortex, linked with executive function. These findings suggest that superior endothelial function may help to attenuate age-related declines in WM microstructure in portions of the corpus callosum that interconnect prefrontal brain regions involved in executive function.

Peripheral Endothelial Function After Arterial Switch Operation for D-looped Transposition of the Great Arteries

Coronary artery re-implantation during arterial switch operation in patients with D-looped transposition of the great arteries (D-TGA) can alter coronary arterial flow and increase shear stress, leading to local endothelial dysfunction, although prior studies have conflicting results. Endothelial pulse amplitude testing can predict coronary endothelial dysfunction by peripheral arterial testing. This study tested if, compared to healthy controls, patients with D-TGA after arterial switch operation had peripheral endothelial dysfunction. Patient inclusion criteria were (1) D-TGA after neonatal arterial switch operation; (2) age 9-29 years; (3) absence of known cardiovascular risk factors such as hypertension, diabetes, hypercholesterolemia, vascular disease, recurrent vasovagal syncope, and coronary artery disease; and (4) ability to comply with overnight fasting. Exclusion criteria included (1) body mass index ≥85th percentile, (2) use of medications affecting vascular tone, or (3) acute illness. We assessed endothelial function by endothelial pulse amplitude testing and compared the results to our previously published data in healthy controls (n = 57). We tested 20 D-TGA patients (16.4 ± 4.8 years old) who have undergone arterial switch operation at a median age of 5 days (0-61 days). Endothelial pulse amplitude testing indices were similar between patients with D-TGA and controls (1.78 ± 0.61 vs. 1.73 ± 0.54, p = 0.73).In our study population of children and young adults, there was no evidence of peripheral endothelial dysfunction in patients with D-TGA who have undergone arterial switch operation. Our results support the theory that coronary arterial wall thickening and abnormal vasodilation reported in these patients is a localized phenomenon and not reflective of overall atherosclerotic burden.

Vascular function in asthmatic children and adolescents

Background

Epidemiological studies have demonstrated an increased incidence of cardiovascular events in patients with bronchial asthma, but little is known about the relationship between asthma and vascular function. The purpose of this study was to evaluate endothelial function and arterial stiffness in children and adolescents with asthma.

Methods

A cross-sectional controlled study was designed. Measurements of endothelial function and arterial stiffness in asthmatic (13.6 ± 0.6 years) and control groups (14.9 ± 0.7 years) were taken by the non-invasive peripheral arterial tonometry (EndoPAT2000) determined by using the natural logarithm of the reactive hyperemia index (LnRHI) and the augmentation index (AIx@75%), respectively. Patients with asthma were also administered two questionnaires to evaluate asthma control and quality of life. Exercise functional capacity was evaluated using the Shuttle Walking Test (SWT). Only male participants were included in the present study.

Results

LnRHI and the walked distance during the SWT were similar between groups (p = 0.23 and p = 0.50, respectively). AIx@75% was significantly higher in the asthmatic group (-7.75 ± 1.7) compared to the control group (-15.25 ± 1.8), p < 0.04. In the control group, the LnRHI correlated positively with baseline systolic blood pressure (r = 0.53, p = 0.02) and mean arterial pressure (r = 0.50, p = 0.03), age (r = 0.61, p = 0.007), weight (r = 0.63, p = 0.004) and height (r = 0.56, p = 0.015). Besides that LnRHI correlated with FVC (r = 0.69, p = 0.002), FEV₁, (r = 0.53, p = 0.03) and negatively with Tiffeneau index (FEV₁/FVC%, r = −0.49 p = 0.04). The LnRHI of the asthmatic group did not correlate with the different variables evaluated.

Conclusion

The increased AIx@75% without changes in LnRHI in asthmatic patients could mean that an early detection of vascular impairment may precede endothelial dysfunction, and that different mechanisms may contribute to the pathogenesis and progression of cardiovascular events in this population. A large prospective and randomized controlled study should be done to evaluate the physiopathological mechanisms underlying the association between arterial stiffness and asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0488-3) contains supplementary material, which is available to authorized users.

Common carotid artery diameter responds to intravenous volume expansion: an ultrasound observation

BACKGROUND

In case of intravascular fluid depletion, large veins react to volume expansion with dilation. Little is known about the reaction of arterial vessels. We herein report on the effect of a standardized fluid bolus on the diameter of the common carotid artery (CCA) and its association with hemodynamic parameters, assessed in 20 mechanically ventilated patients after cardiac surgery. CCA was visualized using ultrasound, and the percentage increase in diastolic diameter was calculated by measuring before and after administration of crystalloid infusion solution. Invasive arterial blood pressure and pulse pressure variation (PPV) were assessed in parallel.

RESULTS

Median diastolic CCA diameter was 6.2 (Q1-Q3: 5.4-7.1) mm, and it significantly increased to 6.7 (5.8-7.3) mm upon fluid administration [5.0 (1.9-10.5) % increase]. Mean arterial blood (MAP) pressure likewise increased from 68 (70-73) to 85 (71-100) mmHg, whereas PPV was significantly reduced from 17.6 (16.8-23.9) to 13.2 (6.7-18.1) %. There was a significant association between the change in CCA diameter and the hemodynamic response (delta-MAP: r = 0.53, delta-PPV: r = 0.56; p < 0.05). Furthermore, carotid diameter measured before volume expansion significantly correlated with the delta-PPV upon fluid administration (r = -0.5; p = 0.02).

CONCLUSIONS

Diameter of the CCA increases in response to intravascular volume expansion. Additional studies on the interplay between carotid geometry and intravascular fluid status are necessary.

Evaluation of the Effects of Bile on the Arterial Tonus in a Rabbit Model

Background:

Hepatic artery anastomosis is an essential part of live-donor liver transplantation, and during this anastomosis, an unusual contact between bile and vessel ends is observed. In this study, the effects of this nonphysiological contact in a rabbit model were evaluated.

Methods:

The study was designed in 2 steps—in vitro and in vivo. Three groups were established for the in vitro study. In the first group, vessels were incubated in Krebs solution with 5% bile for 1 minute. In the second group, vessels were kept in Krebs solution with 5% bile for 5 minutes. Vessels in the control group were kept in Krebs solution without bile. All groups were examined for responses to vasodilator and vasoconstrictor agents in organ bath system. The specimens were evaluated immunohistochemically and histopathologically. In the in vivo step, microvascular anastomosis was performed bilaterally. Right carotid artery was anastomosed during bile contamination as study group, and left carotid artery was anastomosed without bile contamination as control group. Blood flow indexes were measured.

Results:

The results of the in vitro study revealed decreased responses to contractile and relaxing agents in the first study group compared with that of the control group (P < 0.0001). There was no response obtained in the second study group. The Doppler ultrasound results revealed no difference between preoperative and postoperative flow indexes (P > 0.05). There was no postoperative spasm in the study group. However, there was significant vasospasm in the control group (P < 0.05).

Conclusions:

Vessels exposed to bile have decreased contractile and relaxing responses, and this effect increases with exposure duration.

A Comparison of Measures of Endothelial Function in Patients with Peripheral Arterial Disease and Age and Gender Matched Controls

This study compared flow-mediated dilatation (FMD), peripheral artery tonometry (PAT), and serum nitric oxide (NO) measures of endothelial function in patients with peripheral artery disease (PAD) against age/gender matched controls. 25 patients (mean age: 72.4 years, M : F 18 : 7) with established PAD and an age/gender matched group of 25 healthy controls (mean age: 72.4 years, M : F 18 : 7) were studied. Endothelial function was measured using the % FMD, reactive hyperemia index (RHI) using PAT and serum NO (μmol). Difference for each method between PAD and control patients and correlation between the methods were investigated. FMD and RHI were lower in patients with PAD (median FMD for PAD = 2.16% versus control = 3.77%, p = 0.034 and median RHI in PAD = 1.64 versus control = 1.92, p = 0.005). NO levels were not significantly different between the groups (PAD median = 7.70 μmol, control median = 13.05 μmol, p = 0.662). These results were obtained in elderly patients and cannot be extrapolated to younger individuals. FMD and PAT both demonstrated a lower hyperaemic response in patients with PAD; however, FMD results in PAD patients were unequivocally reduced whereas half the PAD patients had RHI values above the established threshold for endothelial dysfunction. This suggests that FMD is a more appropriate method for the measurement of NO-mediated endothelial function.