Noninvasive determination of endothelium-mediated vasodilation as a screening test for coronary artery disease: pilot study to assess the predictive value in comparison with angina pectoris, exercise electrocardiography, and myocardial perfusion imaging

Non-invasive imaging in antiphospholipid syndrome to assess subclinical coronary artery disease

Antiphospholipid antibody syndrome (usually named antiphospholipid syndrome, APS) is an autoimmune disorder seen mainly in young people. Clinically, APS is described by pregnancy complications and/or a hypercoagulable state, including the venous or arterial vasculature, and strongly related to antiphospholipid antibodies. Although several cardiac manifestations have been involved with APS, and accelerated atherosclerosis is present in this condition, little is known about cardiovascular (CV) risk and the relation between APS. Several studies have used imaging markers to associate them with the main clinical features of patients with APS and the probability of having subclinical atherosclerosis. However, it has not yet been established which markers are most related to the risk of developing CV diseases (CVD) in these patients. In this narrative review, we focus on non-invasive imaging markers that can predict CVD, including carotid intima-media thickness and carotid plaques assessed by carotid ultrasonography or coronary artery calcium score, which usually by computed tomography. We also examine the evidence about vascular function markers used in APS, such as arterial flow-mediated brachial dilation and artery stiffness measured by the velocity of the pulse wave. We present the current status of non-invasive imaging markers, which suggest the existence of subclinical atherosclerosis in patients with APS. However, new prospective research is required to identify the predictive value of these findings and their modification by current treatments for APS.

Non-INvasive Functional and Anatomic vascular evaluation for the prediction of coronary artery disease: The NINFA study

BACKGROUND

Endothelial function, as assessed with flow-mediated dilatation (FMD), and carotid intima-media thickness (IMT) correlate with the presence and extent of coronary artery disease (CAD). We investigated the incremental value of a combined evaluation of FMD and IMT in predicting the presence of CAD over traditional cardiovascular risk factors.

METHODS

A total of 497 consecutive patients undergoing elective coronary angiography were enrolled in this study. Brachial artery FMD and ultrasound-based carotid IMT were evaluated prior to angiography. CAD was defined as the presence of a ≥ 50% stenosis in at least one coronary artery. SYNTAX score was also calculated. Patients were categorized based on the presence of FMD and IMT values below or above gender-specific median.

RESULTS

Patients with both low FMD and high IMT presented the highest prevalence of CAD, number of diseased vessels, and SYNTAX score. At multivariate analysis, the combination of low FMD and high IMT was the strongest predictor of CAD (OR 3.63, 95% CI 2.19-6.02; p < .001). At ROC curve analysis, the addition of FMD and IMT to a model of traditional risk factors improved the predictive power for the presence of CAD (area under the curve [AUC] of risk factors model 0.715; AUC of risk factors + FMD + IMT 0.780; p < .001). The addition of FMD and IMT to the model of risk factors correctly reclassified 24.9% of patients.

CONCLUSIONS

A combined evaluation of endothelial function and subclinical atherosclerosis at the carotid artery level improves the ability of traditional risk factors to identify patients with CAD.

Mediterranean Diet and Endothelial Function: A Review of its Effects at Different Vascular Bed Levels

The Mediterranean diet has recently been the focus of considerable attention as a palatable model of a healthy diet. Its influence on many cardiovascular risk factors, combined with its proven effect in reducing the risk of cardiovascular events in primary prevention, has boosted scientific interest in this age-old nutritional model. Many of the underlying mechanisms behind its health-giving effects have been revealed, from the modulation of the microbiota to the function of high-density lipoproteins (HDL), and it seems to deliver its health benefits mainly by regulating several key mechanisms of atherosclerosis. In this review, we will review the evidence for its regulation of endothelial function, a key element in the early and late stages of atherosclerosis. In addition, we will assess studies which evaluate its effects on the functioning of different arterial territory vessels (mainly the microvascular, peripheral and central vascular beds), focusing mainly on the capillary, brachial and carotid arteries. Finally, we will evaluate the molecular mechanisms which may be involved.

Serial assessment of endothelial function 1, 6, and 12 months after ST-elevation myocardial infarction

Knowledge about the changes in endothelial function after ST-elevation myocardial infarction (STEMI) is of substantial interest, but serial data are scarce. The aim of the present study was to noninvasively evaluate whether endothelial function, as assessed shortly after primary percutaneous coronary intervention (PPCI) for STEMI, may improve until 12-month follow-up. This prospective observational cohort study was performed in patients in the RESPONSE randomized trial who participated in a substudy and underwent noninvasive assessment of endothelial function at 1 (baseline), 6, and 12-month follow-up after treatment of a STEMI by PPCI. The reactive hyperemia peripheral artery tonometry (RH-PAT) method was used to assess endothelial function (higher RH-PAT index signifies better function). Of the 70 study participants, who were 57.4 ± 9.7 years of age, 55 (78.6%) were male and 9 (13%) had diabetes. The endothelial function deteriorated significantly during follow-up: the RH-PAT index at baseline, 6, and 12-month follow-up was 1.90 ± 0.58, 1.81 ± 0.57, and 1.69 ± 0.49, respectively (p = 0.04). Although patients were carefully treated in outpatient clinics and adequate pharmacological therapy was prescribed, we noted an increase in total cholesterol (p = 0.001), LDL cholesterol (p = 0.002), HbA1C (p = 0.054), and diastolic blood pressure (p = 0.047) However, multivariate analysis revealed that this increase in cardiovascular risk factors could not explain the observed deterioration in endothelial function. In patients with STEMI, we observed a significant deterioration in endothelial function during 12 months after PPCI that could not be explained by changes in the traditional cardiovascular risk profile.

Investigation of vascular endothelial dysfunction in the patients with age-related macular degeneration

PURPOSE

This study aims to evaluate the association between age-related macular degeneration (AMD) and cardiovascular disease by using the noninvasive flow-mediated dilation (FMD) test to show endothelial dysfunction as an indicator of subclinical atherosclerosis.

METHOD

Participants in this study included 30 dry AMD patients, 30 wet AMD patients, and 30 healthy controls without any systemic disease, including AMD. FMD and the intima media thickness (IMT) of the carotid artery were compared between the groups.

RESULTS

Comparison of FMD between the groups showed a 10.96% brachial artery dilation in the healthy controls, 3.99% in the dry AMD group, and 5.03% in the wet AMD group. While a significant difference was not observed between the wet and dry AMD groups, comparison of the control group to the wet and dry AMD groups yielded a significant difference. When brachial artery dilation below 7% was accepted as an abnormal FMD, 26.7% of the healthy controls, 66.7% of the dry AMD patients and 76.7% of the wet AMD patients were found to be abnormal. Similarly, while no significant difference was observed between the wet and dry AMD groups, comparison of the control group with the wet and dry AMD patients yielded a significant difference. When an IMT below 0.7 mm was accepted as abnormal, 26.7% of the healthy controls, 33.3% of the dry AMD, and 43.3% of the wet AMD were found to have an abnormal IMT. However, differences between the groups did not reach statistical significance.

CONCLUSIONS

In this study, use of the FMD test showed endothelial dysfunction among AMD patients. No significant differences were found between the dry and wet AMD patient groups.

Examining the Brachial Artery Reactivity Curve Measured by B-Mode Ultrasound in the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Pilot Study

Brachial artery reactivity was assessed in the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) Pilot Study using B-mode ultrasound. Carotid artery intima-media thickness (CIMT), a known subclinical predictor of cardiovascular disease, also was examined in relation to brachial artery reactivity. A continuous scan was performed on the artery for 8 min (1 min of baseline, 4 min of cuff inflation at 40 mmHg greater than systolic pressure, 3 min after cuff release).

The sample for analysis (n = 78; 43 men, 35 women) consisted of active-duty police officers from a larger sample in the BCOPS pilot study. Means and standard deviations (SDs) stratified by gender were calculated, along with Pearson's correlations between brachial variables, and with CIMT. Arterial diameters (baseline, pre-cuff release, peak) were significantly different ( p < 0.001) between men and women. Peak arterial dilation occurred at 50.77 ± 21.97 sec (49.67 ± 20.22 cardiac cycles) after cuff deflation in men, and 44.66 ± 24.07 sec (44.57 ± 20.36 cardiac cycles) after cuff deflation in women. Mean common carotid artery IMT and mean maximum IMT of all carotid sites were significantly correlated ( p < 0.01) in men (r = 0.691) and women (r = 0.450). Brachial reactivity measures were inversely correlated with CIMT in women, and in contrast, positively correlated in men.

Correlation of endothelial dysfunction measured by flow-mediated vasodilatation to severity of coronary artery disease

OBJECTIVES

Brachial artery ultrasound imaging during reactive hyperemia is widely used tool for quantifying endothelium dependent vasomotion. Angiodefender device is used for non invasive determination of percentage flow mediated vasodilation (FMD). An attempt is made to study whether endothelial dysfunction determined by FMD of brachial artery predicts the presence or absence of coronary artery disease and its correlation with the severity of coronary artery disease.

METHODS

One hundred six patients admitted between May 2014 and April 2015 who were posted for coronary angiography diagnosed to have chronic stable angina on clinical basis and/or by exercise stress test, for evaluation of coronary artery disease were submitted to standard clinical evaluation, calculation of percentage FMD by Angiodefender device. Statistical significance of difference of categorical variables was tested using Fisher's exact test. Sensitivity, specificity, positive predictive value and negative predictive value of FMD were studied.

RESULTS

There was no correlation between number of risk factors and percentage of FMD. Significantly higher proportion of cases with less FMD had higher prevalence of coronary artery disease and vice-versa. Significantly higher proportion of cases with positive stress test had less percentage of FMD and vice-versa. Significantly higher proportion of cases with less percentage of FMD and positive stress test had higher prevalence of obstructive coronary artery disease and vice-versa. Specificity was 100% when percentage of FMD was ≤10.

CONCLUSIONS

FMD an inexpensive and non-invasive test provides information regarding extent and severity of coronary artery disease.

Mediterranean diet improves endothelial function in patients with diabetes and prediabetes: A report from the CORDIOPREV study

BACKGROUND AND AIMS

Endothelial dysfunction (ED) plays a key role in the development of atherosclerotic cardiovascular disease (ASCVD). Likewise, type 2 diabetes (T2D) is a major CVD risk factor. Therefore, our objective was to explore whether long-term consumption of a Mediterranean diet (MedDiet) rich in olive oil or a low-fat diet (LF diet) was associated with an improvement in ED and whether the potential benefits were similar in patients with or without T2D in the CORDIOPREV clinical trial (NCT00924937).

METHODS

Endothelial function was measured in 805 participants who had completed follow-up ultrasound image studies, using ultrasonography of brachial artery to calculate flow mediated vasodilatation (FMD) before and after 1.5 years of intervention with a MedDiet [35% of calories from fat (22% monounsaturated) and 50% from carbohydrates] and LF diet [28% fat (12% monounsaturated) and 55% of calories from carbohydrates]. We categorized participants as patients with T2D, prediabetes, and without T2D according to the American Diabetes Association (ADA) criteria.

RESULTS

MedDiet increased FMD in patients with T2D [5.2 ± 0.4 at 1.5 years vs. 3.8 ± 0.4 at baseline; p=0.04] and prediabetes [4.9 ± 0.4 vs. 3.8 ± 0.4; p=0.04] and induced an improvement in FMD compared to LF diet in patients with diabetes [5.2 ± 0.4 (MedDiet) vs.3.7 ± 0.4 (LF diet); p=0.01]; whereas both diets maintained FMD stable in patients without diabetes.

CONCLUSIONS

Habitual consumption of a MedDiet rich in extra virgin olive oil improves endothelial function in patients with prediabetes and diabetes. This takes great importance given that diet must be the cornerstone of treatment of patients with diabetes at high cardiovascular risk.

E-selectin and sICAM-1, biomarkers of endothelial function, predict recurrence of venous thromboembolism

BACKGROUND

Risk factors for atherosclerosis and venous thromboembolism (VTE) overlap and are mostly associated with endothelial dysfunction (ED). We hypothesized that ED is present in patients after the first episode of acute pulmonary embolism (APE) and predicts the risk of VTE recurrence.

DESIGN AND METHODS

Patients, at least 6months after the first episode of symptomatic, confirmed APE were included in this case-control study. The exclusion criteria were risk factors for cardiovascular diseases and other conditions associated with endothelial dysfunction. Eighty two patients (aged 38±11years; 44 M; 38 F) were enrolled in the study, 39 after provoked APE, 43 after unprovoked APE, and 30 controls (C) (aged 38±12years; 15 M, 15 F). In order to evaluate the endothelial function in patients with a history of APE flow-mediated dilation (FMD) of the brachial artery and biomarkers of endothelial dysfunction (sVCAM-1, sICAM-1, ADMA, E-selectin) were measured. Subsequently all patients were followed up in an outpatient clinic for VTE recurrence.

RESULTS

FMD was more often impaired in APE patients than in controls (5.3% (0.8-20.3) vs. 13.8% (4.1-24.3); p<0.0001). Biomarker levels differed between APE and C groups: sVCAM-1 (631ng/ml (105-2382) vs. 495ng/ml (348-934); p=0.04) and sICAM-1 (679ng/ml (279-1006) vs. 600ng/ml (394-766); p=0.002). There were 19 recurrences of VTE during the at least 12-month follow-up (15 with history of unprovoked-APE and 4 after provoked-APE). E-selectin ≥39ng/ml and sICAM-1≤655ng/ml indicated the group without recurrence of VTE. In a group of 43 unprovoked APE patients both E-selectin<39ng/ml and sICAM-1>655ng/ml were found in 17 subjects. Eleven of them (65%) were diagnosed with recurrent VTE.

CONCLUSIONS

Endothelial function is significantly impaired in patients after an episode of APE as indicated by FMD assessment and biomarker levels. Low concentrations of E-selectin and high levels of sICAM-1 are associated with a high risk of recurrent thromboembolism.

Children With Type 1 Diabetes Have Delayed Flow-Mediated Dilation

OBJECTIVES

Children with type 1 diabetes have accelerated atherosclerosis with early endothelial dysfunction as measured by reduced flow-mediated dilation (FMD) at 60 seconds postischemic stress (early FMD). Delayed dilation may also occur in the presence of cardiovascular risk factors and may be a more sensitive marker. No data exist that evaluate FMD beyond 60 seconds (delayed FMD) in children with type 1 diabetes. We aimed to compare early and delayed FMD in children with type 1 diabetes and in healthy children.

METHODS

We studied 66 children 13.5±2.8 years of age; 29 were males. Of the 66 children, 38 had type 1 diabetes, and 28 were healthy age- and gender-matched controls. Evaluation of brachial artery FMD was performed at 60 seconds (FMD_60s) and 120 seconds (FMD_120s) postischemic stress. Early FMD was defined as peak FMD_60s and delayed FMD as peak FMD_120s. RESULTS: Children with type 1 diabetes had diabetes durations of 5.4±4.6 years and median glycated hemoglobin levels of 8.8 (6.6 to 14)% (73 [49 to 130] mmol/mol). Of the children, 8 with type 1 diabetes and 1 healthy child had delayed FMD; a relationship was seen between the prevalence of early FMD and delayed FMD in children with type 1 diabetes and healthy children, respectively (p=0.019). Children with type 1 diabetes and delayed FMD had lower FMD_60s than children without delayed FMD (2.50±3.61 vs. 6.14±3.83 percentage units; p=0.02). Children with type 1 diabetes had lower FMD_60s than healthy children (5.38±4.0 percentage units; p=0.03) but not FMD_120s (7.56±3.5 percentage units; p=0.47).

CONCLUSIONS

Delayed FMD patterns occur in children with type 1 diabetes and detect children who have more severe vascular abnormalities. The standard FMD_60s remains the better marker to identify children at increased risk for cardiovascular disease.

Review: Endothelial dysfunction and pre-symptomatic atherosclerosis in type 1 diabetes — pathogenesis and identification

The vascular endothelium offers an attractive model for detecting functional abnormalities prior to structural changes in the vasculature. Demonstration of progression from endothelial dysfunction through to atherosclerosis is required. Measurements of forearm bloodflow, biochemical markers and biophysical assessments of the endothelium have been employed as research tools for investigating pre-symptomatic atherosclerosis.

However, studies examining endothelial function in type 1 diabetes have been sparse and conflicting. Differences in methodology and the study populations were potential confounding factors. Augmented vasodilatory prostanoids compensate for reduced nitric oxide bioavailability in determining endothelial function in type 1 diabetes. Hyperglycaemia appears to be the initiating event in type 1 diabetes which promotes a variety of biochemical events which are pathogenic to the endothelium.

Improved understanding of the endothelium may facilitate the development of novel diagnostic tools and interventions targeting the accelerated atherosclerosis associated with type 1 diabetes.

Pro-atherogenic mediators and subclinical atherogenesis are related to epicardial adipose tissue thickness in patients with cardiovascular risk

Objective

To evaluate the relationship between pro-atherogenic biomarkers and epicardial adipose tissue (EAT) thickness in patients with cardiovascular risk factors.

Methods

Plasma nitric oxide (NO), soluble intercellular adhesion molecule-1 and malondialdehyde (MDA) levels, EAT thickness, flow-mediated dilation (FMD) and carotid intima media thickness (CIMT) were determined in patients aged >18 years who were referred for echocardiography for heart ischemia or non-ischemic diseases. Cardiovascular risk factors (Framingham score [FS] ≥ 20) were weighted.

Results

Hypertension, dyslipidaemia and type 2 diabetes mellitus were prevalent (≥55% of 40 patients). Patients with FS ≥ 20 (n = 21) showed significantly higher EAT and CIMT values. Globally, MDA, CIMT, age, waist circumference, high-density lipoprotein cholesterol (HDL-C) and FS were associated with EAT thickness. EAT was significantly associated with NO in patients with FS ≥ 20. Significant differences in EAT thickness were found between patients stratified by NO value, FMD, age, smoking status, dyslipidaemia, type 2 diabetes mellitus and FS. An EAT-associated atherogenic risk (CIMT ≥ 1 mm) model was statistically significant when MDA and type 2 diabetes mellitus were included.

Conclusion

EAT thickness was associated with MDA, CIMT, age, waist circumference, HDL-C and FS globally, but with NO only in patients with FS≥20. EAT may be used to identify vascular damage stage, possibly influenced by MDA and type 2 diabetes mellitus.

The clinical relevance of the percentage flow-mediated dilation index

In 2010, the American College of Cardiology Foundation and American Heart Association could not recommend brachial artery percentage flow-mediated dilation (FMD%) for risk assessment of coronary artery disease (CAD) in asymptomatic adults. We aimed to scrutinise past and recently published findings regarding FMD% in this same context of clinical utility and conclude that (1) the question of whether brachial FMD% is a suitable substitute for coronary vasodilation is addressed by method agreement statistics rather than the correlation coefficients that have been reported in past studies. Also, the much-repeated view that brachial FMD% and coronary vasodilation are "closely related" is not entirely justified, even before the influence of baseline lumen diameters on this relationship is accounted for; (2) along with the specialist training and the considerable time (≥1 h) that is required for the FMD% protocol, the error in individual measurements and population reference ranges is too large for clinical decisions to be robust on individual patients; (3) many interventions that are proposed to change FMD% also change baseline artery diameter, which can bias estimates of any intervention effects on the flow-mediated response per se, and (4) the FMD% index generates spurious correlations between shear rate, artery diameter and endothelial function, which may help to explain the apparent paradoxes of FMD% being higher in obese people and lower in athletes. In conclusion, the clinical relevance of brachial artery flow-mediated dilation is unclear at present. The dependence of the chosen index, FMD%, on initial artery size has contributed to this lack of clarity.

Impaired endothelial function in patients with mild primary hyperparathyroidism improves after parathyroidectomy

BACKGROUND

Primary hyperparathyroidism (PHPT) is associated with cardiovascular morbidity; however, data on the reversibility of cardiovascular disease in mild primary hyperparathyroidism are conflicting. The aim of this study was to assess endothelial function in patients with mild PHPT before and after parathyroidectomy (Ptx).

METHODS

We prospectively evaluated 53 patients with mild PHPT (Group 1; 45 women, eight men; aged 52 ± 3·1 years) and 46 healthy control subjects (Group 2; 38 women, eight men; aged 46 ± 9·5 years). Endothelial function was measured as flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT) using Doppler ultrasonography. Patients with diabetes mellitus, coronary heart disease, impaired renal function, hyperthyroidism, hypothyroidism and a history of smoking were excluded from the study. Patients were studied at baseline and 6-12 months after the first evaluation.

RESULTS

There were no differences with respect to age, gender and BMI between the two groups. Hypertension prevalence was three times higher in group 1 than in controls. % FMD was lower in group 1 than in group 2 (2·6 ± 1·2 vs 14·8 ± 9·6, P < 0·001). CIMT was higher in patients with PHPT than controls (0·69 ± 0·18 vs 0·61 ± 0·12, P = 0·045). This significance remained when hypertensive patients were excluded from the analysis. While FMD and CIMT improved significantly after Ptx, there were no differences in mild PHPT patients who followed without parathyroidectomy.

CONCLUSION

FMD and CIMT are impaired in patients with mild PHPT compared to controls and improved significantly after a successful Ptx. Ptx improves endothelial function in patients with mild PHPT that may lead to decreased cardiovascular morbidity and mortality.

Effects of Olive Oil on Markers of Inflammation and Endothelial Function-A Systematic Review and Meta-Analysis

The aim of the present systematic review was to synthesize data from randomized controlled trials investigating the effects of olive oil on markers of inflammation or endothelial function. Literature search in electronic databases Cochrane Trial Register, EMBASE, and MEDLINE was performed. Thirty studies enrolling 3106 participants fulfilled the selection criteria. Pooled effects of different interventions were assessed as mean difference using a random effects model. Olive oil interventions (with daily consumption ranging approximately between 1 mg and 50 mg) resulted in a significantly more pronounced decrease in C-reactive protein (mean difference: −0.64 mg/L, (95% confidence interval (CI) −0.96 to −0.31), p < 0.0001, n = 15 trials) and interleukin-6 (mean difference: −0.29 (95% CI −0.7 to −0.02), p < 0.04, n = 7 trials) as compared to controls, respectively. Values of flow-mediated dilatation (given as absolute percentage) were significantly more increased in individuals subjected to olive oil interventions (mean difference: 0.76% (95% CI 0.27 to 1.24), p < 0.002, n = 8 trials). These results provide evidence that olive oil might exert beneficial effects on endothelial function as well as markers of inflammation and endothelial function, thus representing a key ingredient contributing to the cardiovascular-protective effects of a Mediterranean diet. However, due to the heterogeneous study designs (e.g., olive oil given as a supplement or as part of dietary pattern, variations in control diets), a conservative interpretation of the results is necessary.

Fenofibrate effects on arterial endothelial function in adults with type 2 diabetes mellitus: A FIELD substudy

OBJECTIVE

Dislipidaemia in type 2 diabetes mellitus contributes to arterial endothelial dysfunction and an increased risk of cardiovascular disease. Fenofibrate, a lipid-regulating peroxisome proliferator-activated receptor-α (PPARα) agonist, has been shown to reduce vascular complications in adults with type 2 diabetes. However, the mechanisms for such benefit are not well understood. We examined the effects of fenofibrate on brachial artery endothelial function in adults with type 2 diabetes.

METHODS

In a prospectively designed substudy of the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, we assessed arterial flow-mediated dilatation (FMD; endothelium-dependent dilatation) and dilator responses to glyceryl trinitrate (GTN, an endothelium-independent dilator) in a subset of 193 representative adults. Traditional risk factors were assessed at baseline, 4 months and 2 years after randomised treatment allocation to fenofibrate (200 mg daily) or placebo. The prespecified primary study endpoint was the difference in FMD between treatment groups at 4 months.

RESULTS

Fenofibrate was associated with a significant improvement at 4 months compared with placebo (+1.05% (absolute); P=0.03); GTN-dilator responses were unchanged (P=0.77). After 2 years, FMD was similar in both groups (P=0.46). In multivariable models, none of the fenofibrate-related changes in lipoproteins and lipids were significantly associated with improved FMD on fenofibrate at 4 months.

CONCLUSION

Treatment with fenofibrate significantly improved arterial endothelial function after 4 months. However, the effect was no longer apparent after 2 years. The long-term beneficial vascular effects of fenofibrate in type 2 diabetes are likely to be mediated via mechanisms other than improvement in endothelium-dependent dilatation of conduit arteries, and may differ for the microcirculation.

Endothelial Cell Inflammation and Antioxidant Capacity are Associated With Exercise Performance and Microcirculation in Patients With Symptomatic Peripheral Artery Disease

We determined whether exercise performance and lower extremity microcirculation were associated with endothelial cell inflammation, oxidative stress, and apoptosis and with circulating biomarkers of inflammation and antioxidant capacity in 160 patients with symptomatic peripheral artery disease (PAD). In a multivariate regression model for peak walking time, significant independent variables included ankle-brachial index (P < .001), age (P = .017), hydroxyl radical antioxidant capacity (P = .008), and endothelial cell nuclear factor K-light-chain-enhancer of activated B cells (NF-κB) activity (P = .015). In multivariate analyses for time to minimum exercise calf muscle hemoglobin oxygen saturation (StO2), significant independent variables included endothelial cell NF-κB activity (P = .043) and calf muscle StO2 at rest (P = .007). Endothelial cell inflammation and circulating biomarkers of inflammation and antioxidant capacity were associated with exercise performance and microcirculation of the ischemic calf musculature during exercise. The clinical implication is that interventions designed to alleviate endothelial cell inflammation and circulating inflammatory biomarkers, such as antioxidant therapy, may improve exercise performance of symptomatic patients with PAD.

Carotid Endothelial VCAM-1 Is an Early Marker of Carotid Atherosclerosis and Predicts Coronary Artery Disease in Swine

Objective

The aim was to determine if endothelial VCAM-1 (eVCAM-1) expression in the common carotid artery (CCA) would correlate with predictive markers of atherosclerotic disease, would precede reduction of markers of endothelial cell function and would predict coronary artery disease (CAD).

Methods and results

Carotid arterial segments (bifurcation, proximal and distal CCA) were harvested from 14 and 24 month-old male castrated familial hypercholesterolemic (FH) swine, a model of spontaneous atherosclerosis. Quantification of local expression of eVCAM-1, intimal macrophage accumulation, oxidative stress, intima-media (I/M) ratio, intima-media thickness (IMT), endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS (p-eNOS) in selected regions of the carotids revealed a relationship between local inflammation and atheroscle-rotic plaque progression. Importantly, inflammation was not uniform throughout the CCA. Endo-thelial VCAM-1 expression was the greatest at the bifurcation and increased with age. Finally, eV-CAM-1 best estimated the severity of CAD compared to blood levels of glucose, hypercholestero-lemia, carotid IMT, and p-eNOS.

Conclusion

Our data suggested that eVCAM-1 was closely associated with atherosclerotic plaque progression and preceded impairment of EDD. Thus, this study supported the use of carotid VCAM-1 targeting agents to estimate the severity of CAD.

Screening tests: a review with examples

Screening tests are widely used in medicine to assess the likelihood that members of a defined population have a particular disease. This article presents an overview of such tests including the definitions of key technical (sensitivity and specificity) and population characteristics necessary to assess the benefits and limitations of such tests. Several examples are used to illustrate calculations, including the characteristics of low dose computed tomography as a lung cancer screen, choice of an optimal PSA cutoff and selection of the population to undergo mammography. The importance of careful consideration of the consequences of both false positives and negatives is highlighted. Receiver operating characteristic curves are explained as is the need to carefully select the population group to be tested.

Endothelial Dysfunction is Associated with Occult Coronary Artery Disease Detected by Positron Emission Tomography

OBJECTIVE

Silent myocardial ischemia is common in asymptomatic subjects without a prior history of coronary artery disease (CAD) and is associated with increased morbidity and mortality. Our objective was to determine whether endothelial dysfunction is associated with silent myocardial ischemia and whether the association is independent of genetic and familial factors.

MATERIAL AND METHODS

We examined 416 male monozygotic and dizygotic twins aged 47 to 63 years, free of symptomatic CAD. Subclinical ischemia was diagnosed by [13N] ammonia positron emission tomography at rest and after adenosine stress. Endothelial function was measured by flow-mediated dilation (FMD) of the brachial artery. Generalized estimating equations were used for analysis.

RESULTS

Fixed perfusion defects were found in 24 (6%) twins and reversible perfusion defects in 90 (22%) twins, indicating subclinical ischemia. There was an inverse correlation between FMD and the reversible perfusion defect score (r = - 0.14, p=0.01) but not the fixed defect score (r= -0.017, p=0.73). From the lowest to the highest quartile of FMD, the prevalence of reversible defects decreased 28% to 14%, p=0.008. In multivariable analysis, reversible defects were significantly associated with each quartile of decreasing FMD (OR =1.3; 95% 1.1, 2.5). In 54 twin pairs discordant for endothelial dysfunction (FMD ≤ 7% dilation from baseline), twins with endothelial dysfunction had 9% higher likelihood of having perfusion defects than their co-twins without endothelial dysfunction (p=0.041).

CONCLUSIONS

Endothelial dysfunction is independently associated with silent ischemia and this association is not confounded by genetic or other shared familial factors.

Assessment of endothelial dysfunction in Asian Indian patients with chronic kidney disease and changes following renal transplantation

BACKGROUND

Endothelial dysfunction may explain increased cardiovascular risk in patients with chronic kidney disease (CKD).

METHODS

Brachial artery was imaged during reactive hyperemia (endothelium-dependent, flow-mediated dilatation, FMD) and during glyceryl trinitrate-mediated dilatation (nitroglycerine-mediated dilatation, NMD, endothelium-independent) in 108 patients with CKD and three months following renal transplantation (RT) in 60 of them.

RESULTS

Patients with CKD had significantly lower FMD vs. controls (9.1% vs. 18.3%, p < 0.001) while NMD was comparable (19.8% vs. 21.8%, p = ns). Impaired FMD (<4.5%) was observed in 26.8% patients with CKD and was more common in those on hemodialysis (HD; 28.4% vs. 15.4%) vs. those not on dialysis. FMD for patients with glomerular filtration rate (GFR) 15-60 vs. <15 mL/min/1.73 m(2) was 12.9% and 8.8% (p = 0.05; respectively -29% and -52% lower vs. controls), indicating reduced FMD with increasing CKD severity. There was +72% increase in FMD following RT (9.1 to 15.7%, p < 0.001) while mean NMD was unchanged. Following RT, only 3.3% had impaired FMD.

CONCLUSIONS

Patients with CKD have endothelial dysfunction as evidenced by reduced FMD. Decreased FMD indicating worsening endothelial function was noted with increasing severity of CKD. Within three months of RT, there was significant improvement in FMD, while NMD values did not change.

Evaluation of the Associations between Vascular Endothelial Function and Coronary Artery Stenosis in Patients with Elevated Blood Pressure during Coronary Angiography

<p><b>Objectives:</b> The aim of the present study is to explore the correlation between vascular endothelial function and coronary artery stenosis in non-hypertensive patients with elevated blood pressure under stress.</p><p><b>Methods:</b> This study included 1141 patients suspected of having coronary artery disease (CAD) without hypertension. Coronary arteriography and ultrasonic detection were used to measure the flow-mediated dilatation (FMD) function in the brachial artery. Patients were divided into 2 groups according to coronary angiography: experiment group, patients with blood pressure ? 140/90 mm Hg; control group, patients with blood pressure <140/90 mm Hg. The correlation between vascular endothelial function and coronary artery stenosis was observed.</p><p><b>Results:</b> The majority of the patients in the control group were found to have either normal coronary arteries or stenosis <50%. Patients in the experiment group (those with invasive blood pressure [IBP] >140/90) were more likely to have some degree of coronary artery stenosis. Specifically, there were significantly more patients with >50% stenosis in the experiment when compared with the control group (<i>P</i> < .05). The FMD in the experiment group was significantly lower than that in the control group (<i>P</i> < .05).</p><p><b>Conclusion:</b> The non-hypertensive patients with elevated blood pressure under stress had coronary artery stenosis, which was associated with vascular endothelial dysfunction.</p>

Greater endothelial apoptosis and oxidative stress in patients with peripheral artery disease

We compared apoptosis, cellular oxidative stress, and inflammation of cultured endothelial cells treated with sera from 156 subjects with peripheral artery disease (PAD) and 16 healthy control subjects. Furthermore, we compared circulating inflammatory, antioxidant capacity, and vascular biomarkers between the two groups. The PAD group had a 164% higher value for endothelial cell apoptosis (P < 0.001) and a 62% higher value for endothelial cellular reactive oxygen species production (P < 0.001) than the control group. Furthermore, the PAD group had lower systemic antioxidant capacity measured by hydroxyl radical antioxidant capacity activity (P < 0.001), higher inflammatory and vascular measures of high-sensitivity C-reactive protein (P < 0.001), interleukin-8 (P < 0.001), serum amyloid A (P < 0.001), vascular cell adhesion molecule-1 (P < 0.001), adiponectin (P < 0.001), apolipoprotein B (P = 0.013), apolipoprotein CIII (P = 0.035), lower vascular endothelial growth factor-A (P < 0.001), and hepatocyte growth factor (P < 0.001) than the control group. Subjects with PAD have greater endothelial apoptosis and oxidative stress than control subjects with low burden of comorbid conditions and cardiovascular risk factors. Furthermore, subjects with PAD have lower systemic antioxidant capacity and angiogenic measures and higher circulating inflammatory parameters.

Upstream Transcription Factor 1 (USF1) allelic variants regulate lipoprotein metabolism in women and USF1 expression in atherosclerotic plaque

Upstream transcription factor 1 (USF1) allelic variants significantly influence future risk of cardiovascular disease and overall mortality in females. We investigated sex-specific effects of USF1 gene allelic variants on serum indices of lipoprotein metabolism, early markers of asymptomatic atherosclerosis and their changes during six years of follow-up. In addition, we investigated the cis-regulatory role of these USF1 variants in artery wall tissues in Caucasians. In the Cardiovascular Risk in Young Finns Study, 1,608 participants (56% women, aged 31.9 ± 4.9) with lipids and cIMT data were included. For functional study, whole genome mRNA expression profiling was performed in 91 histologically classified atherosclerotic samples. In females, serum total, LDL cholesterol and apoB levels increased gradually according to USF1 rs2516839 genotypes TT < CT < CC and rs1556259 AA < AG < GG as well as according to USF1 H3 (GCCCGG) copy number 0 < 1 < 2. Furthermore, the carriers of minor alleles of rs2516839 (C) and rs1556259 (G) of USF1 gene had decreased USF1 expression in atherosclerotic plaques (P = 0.028 and 0.08, respectively) as compared to non-carriers. The genetic variation in USF1 influence USF1 transcript expression in advanced atherosclerosis and regulates levels and metabolism of circulating apoB and apoB-containing lipoprotein particles in sex-dependent manner, but is not a major determinant of early markers of atherosclerosis.

Impaired vascular endothelial growth factor A and inflammation in patients with peripheral artery disease

We compared apoptosis, cellular oxidative stress, and inflammation of cultured endothelial cells treated with sera from 130 patients with peripheral artery disease (PAD) and a control group of 36 patients with high burden of comorbid conditions and cardiovascular risk factors. Second, we compared circulating inflammatory, antioxidant capacity, and vascular biomarkers between the groups. The groups were not significantly different (P > .05) on apoptosis, hydrogen peroxide, hydroxyl radical antioxidant capacity, and nuclear factor κ-light-chain enhancer of activated B cells. Circulating tumor necrosis factor α (TNF-α; P = .016) and interleukin 8 (IL-8; P = .006) were higher in the PAD group, whereas vascular endothelial growth factor A (VEGF-A; P = .023) was lower. The PAD does not impair the endothelium beyond that which already occurs from comorbid conditions and cardiovascular risk factors in patients with claudication. However, patients with PAD have lower circulating VEGF-A than the control group and higher circulating inflammatory parameters of TNF-α and IL-8.

Folate fortification and supplementation do not provide vascular health benefits in type 1 diabetes

OBJECTIVE

To evaluate the lowest effective dose-response of folic acid on endothelial function in children with type 1 diabetes.

STUDY DESIGN

A randomized, double-blind, crossover, placebo-controlled trial was conducted in 20 children with type 1 diabetes (age range 10-18 years) after mandatory folate fortification in Australia. Each child received orally 4 interventions (1 per month)-3 folic acid doses (0.5, 2, and 5 mg) and 1 placebo dose--in random order. The primary outcome was 2-hour postintervention change in endothelial function measured with flow-mediated dilatation (FMD). Thirty-five children with type 1 diabetes from our folic acid interventional trial before folate fortification were used for comparison.

RESULTS

All children completed the study. There were no differences in baseline FMD or folate status between the visits. Folic acid supplementation increased serum folate (P = .0001) and red cell folate (P < .0001), but none of the doses improved FMD (P = .96). Baseline serum folate and red cell folate levels and FMD and glyceryl trinitrate-mediated dilatation were significantly higher in these children compared with children from our trial before mandatory folate fortification (P = .0001, .0001, .014, and .04, respectively).

CONCLUSIONS

Folate status and vascular function have improved in children with type 1 diabetes since the introduction of mandatory folate fortification, but the beneficial endothelial effects of additional folic acid are no longer present.

Cardiovascular Protective Effects of Adjunctive Alternative Medicine (Salvia miltiorrhiza and Pueraria lobata) in High-Risk Hypertension

Introduction. Hypertension in association with diabetes (DM), renal impairment (RI), and left ventricular hypertrophy (LVH) increases the risk of future cardiovascular events. We hypothesize, traditional herbal medicines Danshen and Gegen (D&G) have beneficial effects on atherogenesis in these high-risk hypertensive subjects. Subjects and Methods. 90 asymptomatic hypertensive subjects associated with LVH (63.3%), DM (62.2%), or RI (30%) were randomized to receive D&G herbal capsules 1 gm/day, 2 gm/day, or identical placebo capsules in double-blind and parallel fashion for 12 months. Brachial flow-mediated dilation (endothelium-dependent dilation, FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. All data were analyzed using the Statistical Package for Social Sciences in Windows 16.0. Results. Their mean age was 55 ± 8 years, and 74.4% were male. After 12 months of adjunctive therapies and compared with baseline, there were no significant changes in blood pressure, heart rate, hematological, glucose, and creatinine profiles in both placebo and D&G groups. FMD improved significantly during D&G (P = 0.0001) and less so after placebo treatment (P = 0.001). There was a mild but significant decrease in carotid IMT after D&G (P < 0.001) but no significant changes after placebo. A trend of better improvement in FMD after higher versus lower D&G dosages was seen. D&G were well tolerated, with no significant adverse events or blood biochemistry changes. Conclusion. D&G adjunctive treatment was well tolerated and significantly improved atherogenesis in high-risk hypertensive patients, with potential in primary atherosclerosis prevention.

Endothelial function in mild primary hyperparathyroidism

BACKGROUND

It is not known if endothelial dysfunction, an important early event in the pathogenesis of atherosclerosis, is present in mild primary hyperparathyroidism (PHPT) and if so, whether it improves following parathyroidectomy.

DESIGN

We measured flow-mediated vasodilation (FMD), which estimates endothelial function by ultrasound imaging, in patients prior to and 6 and 12 months after parathyroidectomy.

RESULTS

Forty-five patients with mild PHPT [80% female, 61 ± 1 (mean ± SE) years, serum calcium 2·65 ± 0·03 mm (10·6 ± 0·1 mg/dl), PTH 10·5 ± 0·7 pm (99 ± 7 pg/ml), 25-hydroxyvitamin D (25OHD) 70·3 ± 3·7 nm (28·2 ± 1·5 ng/ml)] were studied. Baseline FMD was normal (4·63 ± 0·51%; reference mean: 4·4 ± 0·1%) and was not associated with serum calcium, PTH or 25OHD levels. In the group as a whole, FMD did not change after surgery (6 months: 4·38 ± 0·83%, P = 0·72; 12 months: 5·07 ± 0·74%, P = 0·49). However, in those with abnormal baseline FMD (<2·2%; n = 15), FMD increased by 350%, normalizing by 6 months after surgery (baseline: 0·81± 0·19%; 6 months: 3·18 ± 0·79%, P = 0·02 vs baseline; 12months: 3·68 ± 1·22%, P = 0·04 vs baseline). Baseline calcium, PTH and 25OHD levels did not differ between those with abnormal vs normal FMD, nor did these indices predict postoperative change in FMD.

CONCLUSIONS

FMD is generally normal in patients with mild PHPT and is unchanged 1 year after parathyroidectomy. Although FMD may normalize after surgery in patients with baseline abnormalities, data do not support using endothelial dysfunction as an indicator for parathyroidectomy.

Blood flow-restricted exercise in space

Prolonged exposure to microgravity results in chronic physiological adaptations including skeletal muscle atrophy, cardiovascular deconditioning, and bone demineralization. To attenuate the negative consequences of weightlessness during spaceflight missions, crewmembers perform moderate- to high-load resistance exercise in conjunction with aerobic (cycle and treadmill) exercise. Recent evidence from ground-based studies suggests that low-load blood flow-restricted (BFR) resistance exercise training can increase skeletal muscle size, strength, and endurance when performed in a variety of ambulatory populations. This training methodology couples a remarkably low exercise training load (approximately 20%-50% one repetition maximum (1RM)) with an inflated external cuff (width, ranging between approximately 30-90 mm; pressure, ranging between approximately 100-250 mmHg) that is placed around the exercising limb. BFR aerobic (walking and cycling) exercise training methods have also recently emerged in an attempt to enhance cardiovascular endurance and functional task performance while incorporating minimal exercise intensity. Although both forms of BFR exercise training have direct implications for individuals with sarcopenia and dynapenia, the application of BFR exercise training during exposure to microgravity to prevent deconditioning remains controversial. The aim of this review is to present an overview of BFR exercise training and discuss the potential usefulness of this method as an adjunct exercise countermeasure during prolonged spaceflight. The work will specifically emphasize ambulatory BFR exercise training adaptations, mechanisms, and safety and will provide directions for future research.

Diagnostic accuracy of flow-mediated dilatation and intima-media thickness for the presence of significant coronary artery disease

Our purpose was to determine and compare the diagnostic accuracy of flow-mediated dilatation (FMD) and intima-media thickness (IMT). Included were 543 patients. FMD was performed in 543 patients, IMT in 233, and coronary arteriography (CAG) in 442. Analyzing ROC (receiver operating characteristic) curves, FMD </=5.64% showed 89% sensitivity, 62% specificity, 65% positive predictive value (PPV), and 88% negative predictive value (NPV) for the presence of angiographically significant coronary artery disease (CAD). IMT >/=0.788 mm had 71% sensitivity, 62% specificity, PPV 60%, and NPV 73% for the presence of advanced coronary atherosclerosis. FMD >8% or IMT <0.614 mm distinguished a group of patients with a low probability of advanced CAD (95% sensitivity for both and 91% and 81% NPV for FMD and IMT, respectively), whereas FMD </=0% or IMT >/=1.09 mm indicated a high probability for significant coronary stenosis (specificity 95% and NPV 71 and 67%, respectively). FMD and IMT have a clinically applicable diagnostic accuracy for the presence of angiographically significant CAD with a better performance for FMD. FMD and IMT values help us define zones with high and low probability for the presence of advanced coronary atherosclerosis.

Peak and time-integrated shear rates independently predict flow-mediated dilation

BACKGROUND

To determine whether peak and time-integrated shear rates independently predict flow-mediated dilation (FMD).

METHODS

Eleven physically active (25 ± 5 years old) male subjects were tested. FMD was defined as the shear rate-diameter relationship. Hierarchical linear modeling was used to estimate brachial artery diameter change with repeated measures of shear rate nested within each subject. Two models were tested: 1) FMD was induced using ischemia-induced hyperemia (2, 4, 6, and 10 minutes); and 2) FMD was induced following transient (ischemia) and steady-state (forearm heating and handgrip exercise) increases in shear rate. For both models we determined whether peak, in addition to time-integrated shear rates, explained a significant portion of variation for diameter change.

RESULTS

Model 1: Time integrated shear rates explained most of the variation for diameter change. However, peak shear rate explained an additional significant portion of variation. Model 2: The transient condition resulted in significantly (p = 0.012) smaller diameter change per shear rate change than the steady-state condition. However, when specifying peak shear rate as a covariate, the difference between conditions became nonsignificant (p = 0.138).

CONCLUSIONS

Peak and time-integrated shear rates independently predict FMD. Future studies using the FMD test should consider both parameters.

Reduced flow-mediated vasodilation of brachial artery in children with primary snoring

BACKGROUND

Sleep disordered breathing, especially obstructive sleep apnea, is associated with endothelial dysfunction in both adults and children. However, the role of primary snoring (PS) on endothelial function has not been investigated. This study aimed to examine flow-mediated vasodilation (FMD) in both normal weight and overweight children with PS.

METHODS

Children aged 6-18 years with habitual snoring were recruited from our sleep disorder clinic. Non-snoring controls were recruited from participants of a community growth survey. All subjects underwent polysomnography and FMD evaluation on the same day. Children with body mass index of greater than the 85th percentile of the local reference were defined as overweight. Subjects were divided into groups of normal weight, overweight, non-snorers and PS for comparisons.

RESULTS

Two hundred and one children, of whom 83 were overweight, with a mean ± SD age of 11.3 ± 2.7 years were recruited. Seventy three out of 201 children had PS. Both normal weight (7.9 ± 1.3 vs. 8.5 ± 0.9, p=0.012) and overweight subjects (7.4 ± 1.4 vs. 8.1 ± 1.1, p=0.006) with PS had significantly reduced FMD than the non-snoring controls. Multivariate linear regression model showed that PS was independently associated with reduced FMD in both normal weight (p=0.014) and overweight subgroups (p=0.016) after controlling for obstructive apnea hypopnea index.

CONCLUSIONS

PS in children is associated with reduced FMD, independent of obesity.

Assessments of arterial stiffness and endothelial function using pulse wave analysis

Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability.

Use of ultrasound for non-invasive assessment of flow-mediated dilation

The pathological complications of atherosclerosis, namely heart attacks and strokes, remain the leading cause of mortality in the Western world. Preceding atherosclerosis is endothelial dysfunction. There is therefore interest in the application of non-invasive clinical tools to assess endothelial function. The flow-mediated dilation (FMD) test is the standard tool used to assess endothelial function. Reduced FMD is an early marker of atherosclerosis and has been noted for its capacity to predict future cardiovascular disease events. This review discusses the measurement of endothelial function using ultrasound, with a focus on the FMD technique.

Validated methods for assessment of subclinical atherosclerosis in rheumatology

Rheumatoid arthritis, as well as other types of arthritides and connective tissue diseases, is associated with accelerated atherosclerosis, and increased cardiovascular morbidity and mortality. The early signs of cardiovascular disease therefore need to be recognized in patients with these conditions so that effective cardiovascular protection can be introduced. This Review provides an overview of validated techniques that are currently available to determine subclinical atherosclerosis in patients with rheumatic conditions. Techniques for early assessment of endothelial dysfunction include brachial artery flow-mediated vasodilation and laser Doppler flowmetry. Coronary circulation can be assessed by measuring coronary flow reserve using CT, MRI or PET based techniques. The standard indicators of arterial stiffness are pulse-wave velocity and the augmentation index. Carotid atherosclerosis is determined by the common carotid intima-media thickness (ccIMT) measurement or by the assessment of plaques and plaque areas. The combination of ccIMT with plaque assessment is likely to increase the predictive value of this approach. The potential use of a multimarker approach to increase the diagnostic and prognostic value of these clinical assessments is also discussed.

Vitamin B-12 supplementation improves arterial function in vegetarians with subnormal vitamin B-12 status

OBJECTIVE

Vegetarians are more vascular-healthy but those with subnormal vitamin B-12 status have impaired arterial endothelial function and increased intima-media thickness. We aimed to study the impact of vitamin B-12 supplementation on these markers, in the vegetarians.

DESIGN

Double-blind, placebo controlled, randomised crossover study.

SETTING

Community dwelling vegetarians.

PARTICIPANTS

Fifty healthy vegetarians (vegetarian diet for at least 6 years) were recruited.

INTERVENTION

Vitamin B-12 (500 µg/day) or identical placebo were given for 12 weeks with 10 weeks of placebo-washout before crossover (n=43), and then open label vitamin B-12 for additional 24 weeks (n=41).

MEASUREMENT

Flow-mediated dilation of brachial artery (FMD) and intima-media thickness (IMT) of carotid artery were measured by ultrasound.

RESULTS

The mean age of the subjects was 45±9 years and 22 (44%) were male. Thirty-five subjects (70%) had serum B-12 levels <150 pmol/l. Vitamin B-12 supplementation significantly increased serum vitamin B-12 levels (p<0.0001) and lowered plasma homocysteine (p<0.05). After vitamin B-12 supplementation but not placebo, significant improvement of brachial FMD (6.3±1.8% to 6.9±1.9%; p<0.0001) and in carotid IMT (0.69±0.09 mm to 0.67±0.09 mm, p<0.05) were found, with further improvement in FMD (to 7.4±1.7%; p<0.0001) and IMT (to 0.65±0.09 mm; p<0.001) after 24 weeks open label vitamin B-12. There were no significant changes in blood pressures or lipid profiles. On multivariate analysis, changes in B-12 (β=0.25; p=0.02) but not homocysteine were related to changes in FMD, (R=0.32; F value=3.19; p=0.028).

CONCLUSIONS

Vitamin B-12 supplementation improved arterial function in vegetarians with subnormal vitamin B-12 levels, proposing a novel strategy for atherosclerosis prevention.

The effect of different doses of aerobic exercise training on endothelial function in postmenopausal women with elevated blood pressure: results from the DREW study

OBJECTIVES

The aim of this study was to examine the effect of three different doses of aerobic exercise training (corresponding to approximately 50%, 100% and 150% of the National Institutes of Health consensus guidelines) on endothelial function in sedentary obese postmenopausal women with elevated blood pressure. Aerobic exercise training improves endothelial function in individuals with cardiovascular risk; however, it is unknown whether these adaptations occur in a dose-dependent manner.

METHODS

Obese postmenopausal women (n=155) with elevated blood pressure (systolic blood pressure between 120 and 159.0 mm Hg) were randomly assigned to one of four groups: 4, 8 or 12 kilocalories per kilogram of energy expenditure per week (kcal/kg/week) or a non-exercise control group for 6 months. Endothelial function was assessed via flow-mediated dilation (FMD) at baseline and post-intervention.

RESULTS

After exercise training, there was a similar improvement (1.02-1.5%) in FMD in all three exercise groups (p<0.05) compared with control (-0.5%). Change in FMD after exercise training was significantly correlated with FMD at baseline (r= -0.35, p<0.001). Post hoc analyses found a significant improvement in FMD in exercisers (all exercise groups combined) with endothelial dysfunction (FMD < 5.5%) at baseline (1.8%, 95% CI: 1.17 to 2.38; p<0.001) compared with exercisers with normal endothelial function (FMD ≥ 5.5%) (-1.2%; 95% CI: -1.17 to 0.69; p=0.60).

CONCLUSIONS

Aerobic exercise training was associated with improved FMD in postmenopausal women with elevated blood pressure. In addition, exercise training may be more efficacious in improving endothelial function in postmenopausal women with endothelial dysfunction than individuals with normal endothelial function at baseline.

Endothelial function assessment: flow-mediated dilation and constriction provide different and complementary information on the presence of coronary artery disease

AIMS

A number of risk factors for atherosclerosis have been identified, but it remains difficult, on an individual patient basis, to predict how these factors interact in determining the development of coronary artery disease (CAD). It also remains unclear whether the study of endothelial function provides information that is additive to that of traditional risk factors.

METHODS AND RESULTS

Flow-mediated dilation (FMD) and low-flow-mediated constriction (L-FMC) were measured in 451 consecutive patients before coronary angiography. Low-flow-mediated constriction (P< 0.0001) and FMD (P=0.0005) progressively decreased with the number of diseased vessels, and L-FMC showed a significant linear correlation with the SYNTAX score (R=0.38; P< 0.0001). Logistic regression analysis confirmed the association between endothelial function parameters and CAD (P=0.001 for L-FMC, P=0.02 for FMD). Receiver operating characteristic analysis demonstrated that the addition of L-FMC alone and of the combination of FMD and L-FMC improved the predictive power of a model based on traditional risk factors for CAD (area under the curve of the risk factor model=0.716; risk factor model + FMD=0.734, P=0.1 compared with risk factor model; risk factor model + L-FMC=0.771, P=0.004; risk factor model + L-FMC + FMD=0.779, P=0.002). Reclassification statistics showed that the introduction of FMD to the model based on the traditional risk factors correctly reclassified an additional 5% of patients, and that the introduction of L-FMC net correctly reclassified 19% of the patients. There was no correlation between different parameters of endothelial function.

CONCLUSION

Endothelial function assessment provides modest but statistically significant additional information in predicting the presence of CAD.

Impaired brachial flow-mediated dilation is a predictor of a new-onset vascular event after stroke

BACKGROUND AND OBJECTIVE

Brachial arterial flow-mediated dilation (FMD) is associated with an increased risk of vascular events. Our aim was to investigate the relationship between FMD measured in the acute phase of ischemic stroke and a new major adverse vascular event in a consecutive cohort of patients followed up for 48 months after an acute first-ever stroke.

METHODS

We measured FMD in 120 consecutive patients with acute ischemic stroke using high-resolution ultrasonography. FMD was calculated as the relationship between the basal diameter of the brachial artery before and after transient vascular occlusion. Intima-media thickness, extracranial carotid atherosclerosis, stroke severity National Institute of Health Stroke Scale, and modified Rankin Scale at 3 months were also evaluated. A vascular event was defined as any of the following: vascular disease (VD) death, nonfatal myocardial infarction (MI), nonfatal recurrent stroke (RS), claudication or peripheral arterial thrombosis (PVD), angioplasty or cardiac bypass graft surgery.

RESULTS

There were 34 new major adverse vascular events in 32 of 120 patients (26.7%): 21 (61.8%) RS, 5 (14.7%) VD death, 5 (14.7%) MI, and 3 (8.8%) PVD. The presence of carotid artery plaque (81.3 vs. 46%; p < 0.0001), atrial fibrillation (37.5 vs. 14.8%; p = 0.007) and FMD (5.30 ± 7.48 vs. 10.54 ± 7.02; p = 0.001) were associated with new-onset vascular events. FMD ≤4.5% was an independent predictor of new-onset vascular events (hazards ratio 3.48; 95% confidence interval 1.26-9.63; p = 0.01).

CONCLUSIONS

FMD is an independent predictor for a new-onset vascular event after first-ever ischemic stroke.

Acute exercise improves endothelial function despite increasing vascular resistance during stress in smokers and nonsmokers

The present study examined the effect of acute exercise on flow mediated dilation (FMD) and reactivity to neurovascular challenges among female smokers and nonsmokers. FMD was determined by arterial diameter, velocity, and blood flow measured by Doppler ultrasonography after forearm occlusion. Those measures and blood pressure and heart rate were also assessed in response to forehead cold and the Stroop Color-Word Conflict Test (CWT) before and after 30 min of rest or an acute bout of cycling exercise (∼50% VO₂ peak). Baseline FMD and stress responses were not different between smokers and nonsmokers. Compared to passive rest, exercise increased FMD and decreased arterial velocity and blood flow responses during the Stroop CWT and forehead cold in both groups. Overall, acute exercise improved endothelial function among smokers and nonsmokers despite increasing vascular resistance and reducing limb blood flow during neurovascular stress.

Environmental and occupational exposure to lead as a potential risk factor for cardiovascular disease

We have evaluated current knowledge on relations between environmental and occupational exposure to lead with a strong emphasis on cardiovascular disease risk factors, such as the influence of lead compounds on lipid disturbances and arterial blood pressure. In addition, "novel" biochemical and vascular risk factors for cardiovascular diseases were discussed, as well as the combination of lead exposure and genetic predisposition to cardiovascular diseases. Occupationally and educationally, awareness of the unfavourable effects of lead on cardiovascular diseases risk factors should be emphasised. Indeed, accurate identification of the various mechanisms that might account for the effects of lead on the cardiovascular system should be of the highest priority in this field of research.

Endothelial function, a biomarker of subclinical cardiovascular disease, in urban police officers

OBJECTIVE

Police officers were hypothesized to have decreased endothelial function, measured by brachial artery flow-mediated dilation (FMD).

METHODS

We compared FMD in police officers (n = 261) and a population sample of men and women (n = 229), all from the same geographical region and free of clinical cardiovascular disease (CVD).

RESULTS

Compared with the population sample, police officers had significantly increased age-adjusted CVD risk factors (systolic and diastolic blood pressure, total cholesterol, smoking prevalence, and alcohol consumption). Police officers exhibited lower mean FMD after adjustment for age, gender, and traditional CVD risk factors among those aged 55 years or younger (%dilation: police = 5.49%, population = 6.49%; P = 0.04).

CONCLUSIONS

Police officers exhibited decreased endothelial function (lower FMD) compared with the civilian sample, which was not fully explained by traditional CVD risk factors, suggesting that other pathways may contribute to increased CVD risk in law enforcement work.

Effect of long-term and high-dose allopurinol therapy on endothelial function in normotensive diabetic patients

OBJECTIVES

Endothelial dysfunction is a well known risk factor for atherosclerosis. Uric acid levels are associated with endothelial dysfunction and atherosclerosis even if in physiological range. Xanthine oxidase inhibition with allopurinol decreases uric acid levels and oxidative stress and improves endothelial function. We have investigated the effect of high-dose and long-term allopurinol therapy on endothelial function in diabetic normotensive patients.

METHODS

This study is a randomized, single-blind, placebo-controlled trial. Both treatment and placebo groups consisted of 50 patients. In the treatment group, daily oral 900 mg allopurinol was started after randomization and maintained for 12 weeks. Brachial artery flow-mediated dilatation (FMD) and nitrate-induced dilatation (NID) were measured at baseline and after the allopurinol therapy to evaluate endothelial function.

RESULTS

HbA1c and uric acid levels decreased after allopurinol therapy (6.1 ± 2.1 vs 5.5 ± 1.0%, 5.0 ± 0.8 vs 3.3 ± 0.5 mg/dl, respectively, p = 0.01) but no change was observed in the placebo group (7.7 ± 1.9% vs 7.6 ± 2.0%, 5.3±2.1 vs 5.6 ± 0.8 mg/dl, respectively, p > 0.05). FMD and NID increased significantly in the treatment group (5.6 ± 2.1% vs 8.5 ± 1.2%, 10 ± 7.4% vs 14 ± 4.0%, 10 ± 7.4% vs 14 ± 4.0%, respectively, p = 0.01), whereas no change was observed in the placebo group (5.8 ± 1.8% vs 6.1 ± 0.8%, 12 ± 9.5 vs 10 ± 3.8%, respectively, p > 0.05).

CONCLUSION

Long-term and high-dose allopurinol therapy significantly improved endothelial function in diabetic normotensive patients. In addition, allopurinol therapy contributes to the lower HbA1c levels.