Long-term prognostic role of flow-mediated dilatation of the brachial artery after acute coronary syndromes without ST elevation

Identifying the Role of Flow-Mediated Dilatation Assessment in Acute Coronary Syndromes: A Systematic Review

In the context of the global burden of cardiovascular disease, the development of novel, patient-targeted diagnostic and therapeutic strategies is of paramount importance. Acute coronary syndromes (ACS) comprise a subset of cardiovascular disease, with constantly increasing prevalence requiring urgent attention. Flow-mediated dilatation (FMD), a noninvasive method for the evaluation of endothelial function, has been previously implemented in patients with ACS. A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted in order to identify all relevant studies assessing the implementation of FMD among patients with ACS. Our review reflects an effort to present all available data regarding the role of FMD to date, a valuable noninvasive and easy accessible diagnostic tool, in the prognosis of patients with ACS. FMD evaluation in patients with ACS reveals a decline in values, indicative of the presence of endothelial function among this distinct patient group. FMD has also been used to assess the response to various treatments, as well as to predict major adverse cardiovascular events. Dynamic responses to interventions highlights its potential in the evolving field of interventional cardiology.

Is the peripheral microcirculation a window into the human coronary microvasculature?

An increasing body of evidence suggests a pivotal role for the microvasculature in the development of cardiovascular disease. A dysfunctional coronary microvascular network, specifically within endothelial cells-the inner most cell layer of vessels-is considered a strong, independent risk factor for future major adverse cardiac events. However, challenges exist with evaluating this critical vascular bed, as many of the currently available techniques are highly invasive and cost prohibitive. The more easily accessible peripheral microcirculation has surfaced as a potential surrogate in which to study mechanisms of coronary microvascular dysfunction and likewise may be used to predict poor cardiovascular outcomes. In this review, we critically evaluate a variety of prognostic, physiological, and mechanistic studies in humans to answer whether the peripheral microcirculation can add insight into coronary microvascular health. A conceptual framework is proposed that the health of the endothelium specifically may link the coronary and peripheral microvascular beds. This is supported by evidence showing a correlation between human coronary and peripheral endothelial function in vivo. Although not a replacement for investigating and understanding coronary microvascular function, the microvascular endothelium from the periphery responds similarly to (patho)physiological stress and may be leveraged to explore potential therapeutic pathways to mitigate stress-induced damage.

Endothelial Dysfunction and Cardiometabolic Risk Factors in Mexican American Adults: The Cameron County Hispanic Cohort

Endothelial dysfunction assessed by impaired brachial flow-mediated dilation (FMD) predicts incident cardiovascular disease (CVD). We have previously shown that clustering of diabetes mellitus, obesity, and metabolic syndrome in young Hispanic patients was associated with subclinical atherosclerosis. This study aimed to assess determinants of impaired FMD response (%FMD), an earlier marker of atherosclerosis, in a population-based sample of asymptomatic Mexican Americans. Cardiometabolic biomarkers and FMD were obtained from 960 Cameron County Hispanic Cohort participants. Gender-specific median values of %FMD were used to categorize participants into those with %FMD below or above the median. The sample was further stratified into those younger and older than 55 years. Survey-weighted logistic regression analyses were conducted to evaluate the effects of cardiometabolic biomarkers on the %FMD groups. The low %FMD group was significantly older, had higher visceral adipose tissue, systolic blood pressure, or plasma glucose, and had metabolic syndrome compared with those in the high %FMD group. Multivariable-adjusted age-stratified logistic regression analyses showed that in older participants, male gender (odds ratio [OR] = 2.4 [1.4 to 4.2]) and having hypertension (OR = 2.3 [1.3 to 4.3]) or prediabetes mellitus (OR = 3.4 [1.5 to 7.5]) remained significantly associated with odds of low %FMD. In younger participants, high low-density lipoprotein (OR = 2.8 [1.6 to 4.9]) or having the metabolic syndrome (OR = 1.9 [1.1 to 3.6]) were significantly associated with odds of low %FMD. In conclusion, we found age-dependent associations between cardiometabolic biomarkers and an FMD response below the gender-specific median in a sample composed of Mexican Americans without previous CVD. Targeting specific risk factors by age may mitigate progression to incident CVD in this high-risk racial disparity group.

Early Effects of Ticagrelor Versus Clopidogrel on Peripheral Endothelial Function After Non-ST-Elevation Acute Coronary Syndrome and Assessment of Its Relationship With Coronary Microvascular Function

Peripheral endothelial dysfunction is an independent predictor of adverse long-term prognosis after acute coronary syndrome. Data are lacking on the effects of oral P2Y12-inhibitors on peripheral endothelial function in non-ST-elevation acute coronary syndrome (NSTEACS). Furthermore, the relation between peripheral endothelial function and invasive indexes of coronary microvascular function in NSTEACS is unclear. Between March 2018 and July 2020, hospitalized patients with NSTEACS were randomized (1:1) to ticagrelor or clopidogrel. Peripheral endothelial function was assessed with brachial artery flow-mediated vasodilation (FMD). Invasive indexes of coronary microvascular function were obtained using an intracoronary pressure-temperature sensor-tipped wire. In 70 patients included, mean age was 58.6 years, 78.6% (n = 55) were male and 20% (n = 14) had diabetes mellitus. Compared with clopidogrel, ticagrelor significantly improved FMD (14.2 ± 5.4% vs 8.9 ± 5.3%, p <0.001) after a median treatment time of 41.2 hours. The FMD was significantly correlated with the index of microcirculatory resistance (IMR) measured in the infarct-related artery (r = -0.38, p = 0.001), with a stronger correlation found in those who did not have percutaneous coronary intervention (r = -0.52, p = 0.03). Using receiver operating characteristic curve analysis, an FMD of 8.2% identified an IMR of >34 as the threshold, with 77.6% sensitivity and 52.4% specificity. In patients who did not have a percutaneous coronary intervention, an FMD of 11.49% identified an IMR of >34 with 84.6% sensitivity and 80% specificity. In conclusion, ticagrelor significantly improved peripheral endothelial function compared with clopidogrel in patients with NSTEACS. There was a significant correlation between brachial artery FMD and IMR of the infarct-related artery.

Optimal uric acid reduction to improve vascular endothelial function in patients with chronic heart failure complicated by hyperuricemia

Although an association of serum uric acid levels with endothelial function has been shown in various clinical settings, the optimal treatment target that would benefit vascular endothelial function has not been established. We, therefore, conducted a post hoc analysis of the Excited-UA study to identify an optimal target. Patients (N = 133) with chronic heart failure and comorbid hyperuricemia who enrolled in the Excited-UA study were divided into three tertiles based on their serum uric acid level 24 weeks after initiating xanthine oxidase inhibitor treatment with topiroxostat or allopurinol (i.e., groups with low, moderate, and high uric acid levels). Flow-mediated dilation (FMD) and reactive hyperemia index (RHI) values measured by reactive hyperemia peripheral arterial tonometry (RH-PAT) were compared among groups. The change from baseline in the FMD value 24 weeks after treatment was comparable among the three groups. In contrast, the change from baseline in the RHI was significantly different among the three groups (-0.153 ± 0.073, 0.141 ± 0.081 and -0.103 ± 0.104 in the low, moderate, and high uric acid level groups, respectively, P = 0.032). After adjustment for age, body mass index, and concomitant use of diuretics, which differed among the three groups, the change in the RHI in the moderate uric acid level group tended to be higher than that in the high uric acid level group (P = 0.057) and was significantly higher than that in the low uric acid level group (P = 0.020). These results indicate that targeting excessively low uric acid levels by treatment with xanthine oxidase inhibitors might be less beneficial for improving microvascular endothelial function in patients with chronic heart failure. Comparisons of the changes from baseline in vascular endothelial function parameters at 24 weeks among the 3 groups of low, moderae and high uric acid levels achieved with xanthine oxidase inhibitors. After adjustment for confounding factors, such as age, body mass index and concomitant diuretic use, which showed differences among the 3 groups, the change in RHI in the moderate uric acid level group tended to be higher than that in the high uric acid level group and was significantly higher than that in the low uric acid level group.

CHA2DS2 VASc score and brachial artery flow-mediated dilation as predictors for no-reflow phenomenon in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

Background

Following primary percutaneous coronary intervention (PCI), no-reflow is associated with a high rate of long-term unfavorable clinical outcomes. Despite the importance of early no-reflow prediction in cardiovascular medicine, noninvasive assessment is lacking. This study aimed to evaluate the preprocedural CHA2DS2 VASc score and the brachial artery flow-mediated dilation percentage (FMD%) as predictors of the no-reflow phenomenon in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI.

Results

This study included 150 patients who presented with acute STEMI, underwent primary PCI, and were divided into two groups according to the flow result, reflow group and a no-reflow group. The CHA2DS2 VASc score was calculated and evaluation of endothelial function by measuring the brachial artery FDM% was done for each patient before the procedure. There were 39 (26%) patients in the no-reflow group and 111 (74%) in the reflow group. The no-reflow patients were older and had significantly higher body mass index (BMI), higher frequency of diabetes mellitus, hypertension, history of heart failure, dyslipidemia, Killip class IV on admission, thrombus grade V, multiple affected vessels, conventional stenting, and multiple stents placement, longer ischemic times, higher CHA2DS VASc score, and lower brachial artery FMD% (p-values of < 0.05 for all). Moreover, there was a significant negative correlation between CHA2DS VAS score and preprocedural FMD%, with the higher the score indicating lower FMD among cases (p-value = 0.000).

Conclusions

Preprocedural CHA2DS2 VASc score and the brachial artery FMD can be used as predictors for the no-reflow phenomenon in patients with STEMI, undergoing primary PCI.

Relation of vascular dilator function and cardiac autonomic function with coronary angiography findings in patients with non-ST segment elevation acute coronary syndrome

BACKGROUND

A sizeable number of patients with a diagnosis of non-ST segment elevation acute coronary syndrome show non-obstructive coronary artery disease. In this study we assessed whether differences in vascular and cardiac autonomic function exist between non-ST segment elevation acute coronary syndrome patients with obstructive or non-obstructive coronary artery disease.

METHODS AND RESULTS

Systemic endothelium-dependent and independent vascular dilator function (assessed by flow-mediated dilation and nitrate-mediated dilation of the brachial artery, respectively) and cardiac autonomic function (assessed by time-domain and frequency-domain heart rate variability parameters) were assessed on admission in 120 patients with a diagnosis of non-ST segment elevation acute coronary syndrome. Patients were divided into two groups according to coronary angiography findings: (a) 59 (49.2%) with obstructive coronary artery disease (≥50% stenosis in any epicardial arteries); (b) 61 (50.8%) with non-obstructive coronary artery disease. No significant differences between the two groups were found in both flow-mediated dilation (5.03 ± 2.6 vs. 5.40 ± 2.5%, respectively; P = 0.37) and nitrate-mediated dilatation (6.79 ± 2.8 vs. 7.30 ± 3.4%, respectively; P = 0.37). No significant differences were also observed between the two groups both in time-domain and frequency-domain heart rate variability variables, although the triangular index tended to be lower in obstructive coronary artery disease patients (30.2 ± 9.5 vs. 33.9 ± 11.6, respectively; P = 0.058). Neither vascular nor heart rate variability variables predicted the recurrence of angina, requiring emergency room admission or re-hospitalisation, during 11.3 months of follow-up.

CONCLUSIONS

Among patients admitted with a diagnosis of non-ST segment elevation acute coronary syndrome we found no significant differences in systemic vascular dilator function and cardiac autonomic function between those with obstructive coronary artery disease and those with non-obstructive coronary artery disease.

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.

Coronary Artery Disease and Endothelial Dysfunction: Novel Diagnostic and Therapeutic Approaches

Coronary artery disease is the leading cause of morbidity and mortality worldwide. The most common pathophysiologic substrate is atherosclerosis which is an inflammatory procedure that starts at childhood and develops throughout life. Endothelial dysfunction is associated with the initiation and progression of atherosclerosis and is characterized by the impaired production of nitric oxide. In general, endothelial dysfunction is linked to poor cardiovascular prognosis and different methods, both invasive and non-invasive, have been developed for its evaluation. Ultrasound evaluation of flow mediated dilatation of the branchial artery is the most commonly used method to assessed endothelial function while intracoronary administration of vasoactive agents may be also be used to test directly endothelial properties of the coronary vasculature. Endothelial dysfunction has also been the subject of therapeutic interventions. This review article summarizes the knowledge about evaluation of endothelial function in acute coronary syndromes and stable coronary artery disease and demonstrates the current therapeutic approaches against endothelial dysfunction.

Utility of the cold pressor test to predict future cardiovascular events

INTRODUCTION

The cold pressor test (CPT) is a common and extensively validated test, which induces systemic stress involving immersion of an individual's hand in ice water (normally temperature between 0 and 5 degrees Celsius) for a period of time. CPT has been used in various fields, like examining effects of stress on memory, decision-making, pain and cardiovascular health. Areas covered: In terms of cardiovascular health, current research is mainly interested in predicting the occurrence of cardiovascular (CV) events. The objective of this review is to give an overview of the history and methodology of the CPT, and clinical utility in possibly predicting CV events in CAD and other atherosclerotic diseases. Secondly, we will discuss possible future applications of the CPT in clinical care. Expert opinion: An important issue to address is the fact that the physiology of the CPT is not fully understood at this moment. As pointed out multiple mechanisms might be responsible for contributing to either coronary vasodilatation or coronary vasoconstriction. Regarding the physiological mechanism of the CPT and its effect on the measurements of the carotid artery reactivity even less is known.

Endothelial Function: A Short Guide for the Interventional Cardiologist

An impaired function of the coronary endothelium is an important determinant of all stages of atherosclerosis, from initiation, to mediation of functional phenomena—such as spasm and plaque erosion, to atherothrombotic complications. Endothelial function is modified by therapies, including stent implantation. Finally, endothelial function changes over time, in response to physical stimuli and pharmocotherapies, and its assessment might provide information on how individual patients respond to specific therapies. In this review, we describe the role of the endothelium in the continuum of coronary atherosclerosis, from the perspective of the interventional cardiologist. In the first part, we review the current knowledge of the role of endothelial (dys)function on atherosclerotic plaque progression/instabilization and on the mechanisms of ischemia, in the absence of coronary artery stenosis. In the second part of this review, we describe the impact of coronary artery stenting on endothelial function, platelet aggregation, and inflammation.

Endothelial function as predictor in patients with coronary syndrome treated by percutaneous coronary intervention

We aimed at identifying the predictive role of endothelial function assessed by the RH-PAT index (RHI) for future major cardiovascular events (MACEs) in acute coronary syndrome (ACS) patients treated with percutaneous coronary intervention (PCI). We measured RHI in 308 subjects with ACS, and they were divided into the normal endothelial function (NEF) group and the endothelial dysfunction (DEF) group according to the RHI. The subjects were followed up for a mean of 16 months (interquartile range [IQR]: 14–20 months) after PCI treatment, and their MACEs were also recorded. Cumulative incidence curves were constructed for time-to-event variables with Kaplan–Meier estimates and compared using the log-rank test. The overall incidence of MACEs was 25.39% in the DEF group and 15.96% in the NEF group (P<0.05). Kaplan–Meier analysis also demonstrated a significantly higher probability of MACEs in the DEF group than in the NEF group (log-rank test: P<0.05). Multivariate Cox hazard analysis identified RHI (Model 2, adjusted by blood pressure, hazard ratio [HR]: 0.425; 95% confidence interval [CI]: 0.198–0.914; P=0.029) and SYNTAX score (HR: 1.043; 95% CI: 1.019–1.067; P<0.001) as independent predictors of future MACEs after PCI treatment in ACS patients. Endothelial function measured by reactive hyperemia-peripheral arterial tonometry (RH-PAT) is impaired in ACS subjects treated with PCI. The RHI was an independent predictor of MACEs, suggesting that RHI may be useful as a candidate biomarker in the risk stratification of patients with ACS after PCI treatment.

Effects of uric acid on vascular endothelial function from bedside to bench

This study was designed to investigate the effects of uric acid on vascular endothelial function in measurements carried out either at the bedside or the laboratory bench. First, we performed reactive hyperemia peripheral arterial tonometry using an EndoPAT 2000 device and measured serum uric acid levels in 92 outpatients with hypertension. The reactive hyperemia index (RHI) showed no correlation with serum uric acid level (R = -0.125, P = 0.235) in either overall patients or in a high-risk group of 51 patients with complications such as cardiovascular and cerebrovascular diseases, chronic kidney disease, and/or diabetes (R = -0.025, P = 0.860). However, in the remaining 41 patients in the low-risk group, RHI correlated negatively with serum uric acid level (R = -0.335, P = 0.032). Multiple regression analysis showed that serum uric acid level predicted RHI (R = -0.321, P = 0.043) in the low-risk group independent of age, body mass index, systolic blood pressure, and low density lipoprotein-cholesterol level. We then performed an in-vitro study using the WST-8 assay in human umbilical vein endothelial cells, which showed that hypoxic conditions reduced cell viability. Treatment with uric acid caused a further reduction in cell viability, while ascorbic acid improved viability. Using Western blot analysis, we observed that uric acid reduced endothelial nitric oxide synthase phosphorylation during hypoxic conditions. Serum uric acid level is associated with peripheral vascular endothelial function in patients with low-risk hypertension and uric acid could directly impair endothelial function under hypoxic conditions. These results are relevant to the interventional studies examining the cardiovascular protective effect of hypouricemic agents.

Serial assessment of endothelial vasomotor function using optimal medical therapy predicts clinical outcomes in patients after complete coronary revascularization

Objective

Previous studies have demonstrated the importance of intensive optimal medical therapy (OMT) in patients with coronary artery disease (CAD). To investigate our hypothesis that patients with and without OMT achievement differed with respect to the risk of future cardiac events, we investigated the endothelial function in patients with CAD who underwent percutaneous coronary intervention (PCI) and contemporary medical therapy.

Methods

We conducted a prospective longitudinal cohort study to evaluate the endothelial function in 96 consecutive patients at 12 h after admission and 3 months at <12 h after admission and at 3 months after discharge by measuring the brachial artery dilatation after 5 min of forearm ischemia flow-mediated dilation (FMD). OMT achievement was defined as systolic blood pressure of ≤130 mm Hg, low-density lipoprotein cholesterol of ≤100 mg/dl, and hemoglobin A1c level of ≤7.0%. The primary endpoint was the incidence of composite major adverse cardiac or cerebrovascular events (MACCE) at 36 months.

Results

Forty-nine (51%) patients achieved all three risk factor targets at 3 months. Although baseline FMD values did not differ between the OMT achievement and non-achievement groups, the 3-month FMD significantly improved in the OMT achievement group (6.6±3.5 vs. 5.2±2.9, p=0.03). Patients with improved FMD at 3 months had a lower rate of 36-month MACCE than those with persistently impaired FMD. A multiple Cox hazards analysis showed that OMT was a protective predictor of MACCE (hazard ratio, 0.19; 95% confidence interval, 0.04–0.88, p=0.03).

Conclusion

This study demonstrated a significant association between the serial measurement of endothelial function with OMT and the clinical outcome in patients after PCI.

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.

Early peripheral endothelial dysfunction predicts myocardial infarct extension and microvascular obstruction in patients with ST-elevation myocardial infarction

INTRODUCTION AND OBJECTIVES

The role of endothelial dysfunction (ED) in patients with ST-elevation myocardial infarction (STEMI) is poorly understood. Peripheral arterial tonometry (PAT) allows non-invasive evaluation of ED, but has never been used for this purpose early after primary percutaneous coronary intervention (P-PCI). Our purpose was to analyze the relation between ED assessed by PAT and both the presence of microvascular obstruction (MVO) and infarct extension in STEMI patients.

METHODS

ED was assessed by the reactive hyperemia index (RHI), measured by PAT and defined as RHI <1.67. Infarct extension was assessed by troponin I (TnI) release and contrast-enhanced cardiac magnetic resonance (ceCMR). MVO was assessed by ceCMR and by indirect angiographic and ECG indicators. An echocardiogram was also performed in the first 12 h.

RESULTS

We included 38 patients (mean age 60.0±13.7 years, 29 male). Mean RHI was 1.87±0.60 and 16 patients (42.1%) had ED. Peak TnI (median 118 mg/dl, IQR 186 vs. 67/81, p=0.024) and AUC of TnI (median 2305, IQR 2486 vs. 1076/1042, p=0.012) were significantly higher in patients with ED, who also showed a trend for more transmural infarcts (63.6% vs. 22.2%, p=0.06) and larger infarct mass on ceCMR (median 17.5%, IQR 15.4 vs. 10.1/10.3, p=0.08). Left ventricular ejection fraction (LVEF) was lower and wall motion score index (WMSI) was higher on both echocardiogram and ceCMR in patients with ED. On ceCMR, MVO was more frequent in patients with RHI <1.67 (54.5% vs. 11.1%, p=0.03). ECG and angiographic indicators of MVO all showed a trend toward worse results in these patients.

CONCLUSIONS

The presence of ED assessed by PAT 24 h after P-PCI in patients with STEMI is associated with larger infarcts, lower LVEF, higher WMSI and higher prevalence of MVO.

Relation between high levels of myeloperoxidase in the culprit artery and microvascular obstruction, infarct size and reverse remodeling in ST-elevation myocardial infarction

MAIN OBJECTIVE

To better understand the role of myeloperoxidases (MPO) in microvascular obstruction (MO) phenomenon and infarct size (IS) using cardiac magnetic resonance (CMR) data in patients with acute myocardial infarction (AMI).

METHOD

40 consecutive patients classified according to the median level of MPO in the culprit artery. A CMR study was performed during the week following AMI and at 6 months, with late gadolinium enhancement sequences.

RESULTS

Persistent MO was observed in the same proportion (50 vs. 65%, p = 0.728) between the low vs. high MPO group levels. However, the extent of the microvascular obstruction was significantly greater in the high-MPO group (6 (0-9) vs.16.5 (0-31), p = 0.027), together with a greater infarct size, and a trend towards a lower left ventricular ejection fraction (LVEF) (p = 0.054) at one week. CMR data at 6 months showed that reverse systolic remodeling was two fold more present in the low-MPO group (p = 0.058). Interestingly, the extent of MO (8.5 (6.5-31) vs. 4.1 (3-11.55), p = 0.042) and IS remained significantly greater (24.5 (9.75-35) vs. 7.5 (2.5-18.75), p = 0.022) in the high-MPO group. Moreover, MPO in the culprit artery appeared to correlate positively with MPO in non-culprit arteries and serum, and with troponin levels and peak CK.

CONCLUSION

This patient-based study revealed in patients after AMI that high MPO levels in the culprit artery were associated with more severe microvascular obstruction and greater IS. These findings may provide new insights pathophysiology explanation for the adverse prognostic impact of MO.

Endothelial Function in Patients with Hematologic Malignancies Undergoing High-Dose Chemotherapy Followed by Hematopoietic Stem Cell Transplantation

The aim of the study was to examine endothelial function in patients with hematological malignancies treated with high-dose chemotherapy followed by hematopoietic stem cell transplantation. The studies were conducted on 43 consecutive patients qualified for HSCT following high-dose chemotherapy based on the current standards. Then, due to exclusion criteria, a group of 38 patients were chosen for further investigations. Evaluation of endothelial function by means of flow-mediated dilatation (FMD) was conducted in patients with hematological malignancies before HSCT (test A) and after HSCT (test B). Brachial artery diameter (BAD) after occlusion, change in BAD and FMD were significantly lower after HSCT as compared to the results obtained before the transplantation (p < 0.05). The regression analysis indicated that administration of fludarabine and cytarabine, and also higher blood concentrations of creatinine represented risk factors for the impairment of endothelial function expressed as decreased FMD value. In patients with hematopoietic malignancies treated with HSCT, endothelial function assessed by the flow-mediated dilatation was impaired after chemotherapy and stem cell administration.

Association between glycemic control and morning blood surge with vascular endothelial dysfunction in type 2 diabetes mellitus patients

OBJECTIVE

Morning blood pressure surge (MBPS) is an independent predictor of cardiovascular events. However, little is known about the association between glycemic control and MBPS, and its effect on vascular injury in patients with type 2 diabetes mellitus (T2DM). The current study examined the association between glycemic control and MBPS and the involvement of MBPS in the development of vascular dysfunction in T2DM patients.

MATERIALS AND METHODS

One hundred and twenty-two consecutive T2DM outpatients from the Department of Cardiology and Endocrinology were enrolled in this study. We did MBPS in T2DM patients, 85 (male) (69.7%) patients and 37 (female) patients (30.3%); mean age 60.1 ± 9.39; (n = 122) using 24 h ambulatory blood pressure monitoring and assessed vascular function by brachial artery flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD).

RESULTS

The correlation between MBPS and various clinical variables were examined by single regression analysis in all subjects. MBPS showed significant and positive correlation with pulse rate (P = 0.01), fasting blood sugar (P = 0.002), and postprandial blood sugar (P = 0.05). To further confirm the association of insulin resistance (IR) with MBPS in T2DM patients, we examined the correlation between homeostasis model assessment-IR (HOMA-IR), an established marker of IR and MBPS in diabetic (DM) patients who were not taking insulin no significant association with MBPS in T2DM patients (P = 0.41), angiotensin-converting enzyme/angiotensin receptor blocker (P = 0.07). We examined the relationship between MBPS and vascular injury by measuring endothelium-dependent FMD and endothelium-independent NMD in T2DM patients. Among the various traditional risk factors for atherosclerosis such as DM duration (P = 0.04), platelet reactivity (P = 0.04) and morning surge (P = 0.002) emerged as significant factors. HOMA-IR was a negative correlation with FMD.

CONCLUSIONS

The current study demonstrated that poor glycemic control and IR have predictive value for the occurrence of MBPS in T2DM patients, which might be significantly associated with endothelial dysfunction.

Endothelial dysfunction evaluated by peripheral arterial tonometry is related with peak TnI values in patients with ST elevation myocardial infarction treated with primary angioplasty

PURPOSE

The role of endothelial-dependent function in patients with acute ST elevation myocardial infarction (STEMI) is not clear. Endothelial dysfunction may contribute to the pathophysiological processes occurring after STEMI and influence the extension of myocardial necrosis. Endothelial-dependent dysfunction evaluated by peripheral arterial tonometry (PAT) has already showed to be correlated with microvascular coronary endothelial dysfunction. Our purpose was to evaluate the impact of endothelial dysfunction on peak Troponin I (TnI) values, as a surrogate for the extension of myocardial infarction, in patients with STEMI treated with primary angioplasty (P-PCI).

METHODS

58 patients with STEMI treated with P-PCI (mean age 59.0 ± 14.0 years, 46 males) were included. Endothelial function was assessed by reactive hyperaemia index (RHI) determined by PAT. Patients were divided in two groups according to the previously reported RHI threshold for high risk (1.67). The extension of myocardial necrosis was evaluated by peak TnI levels.

RESULTS

RHI median value was 1.78 (IQR0.74);25 patients had endothelial dysfunction (RHI b 1.67). The two groups had no significant differences in age, gender, main risk factors and pain-to-balloon time. Patients with an RHI b 1.67 had significant larger infarcts: TnI 73.5 ng/mL (IQR 114.42 ng/mL) versus TnI 33.2 ng/mL (IQR 65.2 ng/mL); p = 0.028. On multivariate analysis, the presence of an RHI b 1.67 kept significant impact on TnI peak values (p=0.02).

CONCLUSIONS

The presence of endothelial-dependent dysfunction, assessed by PAT, is related with higher peak TnI values in STEMI patients treated with P-PCI. These results strength the possibility that endothelial-dependent dysfunction may be a marker of poor prognosis and eventually a therapeutic target in patients with STEMI.

Prognostic Value of Flow-Mediated Vasodilation in Brachial Artery and Fingertip Artery for Cardiovascular Events: A Systematic Review and Meta-Analysis

BACKGROUND

Endothelial dysfunction plays a pivotal role in cardiovascular disease progression, and is associated with adverse events. The purpose of this systematic review and meta-analysis was to investigate the prognostic magnitude of noninvasive peripheral endothelial function tests, brachial artery flow-mediated dilation (FMD), and reactive hyperemia--peripheral arterial tonometry (RH-PAT) for future cardiovascular events.

METHODS AND RESULTS

Databases of MEDLINE, EMBASE, and the Cochrane Library were systematically searched. Clinical studies reporting the predictive value of FMD or RH-PAT for cardiovascular events were identified. Two authors selected studies and extracted data independently. Pooled effects were calculated as risk ratio (RR) for continuous value of FMD and natural logarithm of RH-PAT index (Ln_RHI) using random-effects models. Thirty-five FMD studies of 17 280 participants and 6 RH-PAT studies of 1602 participants were included in the meta-analysis. Both endothelial function tests significantly predicted cardiovascular events (adjusted relative risk [95% CI]: 1% increase in FMD 0.88 [0.84-0.91], P<0.001, 0.1 increase in Ln_RHI 0.79 [0.71-0.87], P<0.001). There was significant heterogeneity in the magnitude of the association across studies. The magnitude of the prognostic value in cardiovascular disease subjects was comparable between these 2 methods; a 1 SD worsening in endothelial function was associated with doubled cardiovascular risk.

CONCLUSIONS

Noninvasive peripheral endothelial function tests, FMD and RH-PAT, significantly predicted cardiovascular events, with similar prognostic magnitude. Further research is required to determine whether the prognostic values of these 2 methods are independent of each other and whether an endothelial function-guided strategy can provide benefit in improving cardiovascular outcomes.

A meta-analysis of published studies of endothelial dysfunction does not support its routine clinical use

BACKGROUND

Endothelial dysfunction is a marker of future cardiovascular disease (CVD) risk, yet epidemiological studies have yielded inconsistent results. We therefore studied the association between endothelial dysfunction and CVD under diverse circumstances.

METHODS AND RESULTS

Literature-based meta-analysis of prospective observational studies with ≥ 12 months of follow-up published in Medline and having information on endothelial function and CVD outcomes. Tabular data on participant characteristics, endothelial function assessments and incident CVD outcomes were abstracted from individual studies. Random-effects meta-analysis was used to quantify pooled associations, and I(2) statistic to evaluate between-study heterogeneity. Potential sources of heterogeneity were explored by subgroup analyses and meta-regression. Thirty five studies involving 17,206 participants met the inclusion criteria. During more than 80,000 person-years of observation, up to 2755 CVD events were accrued, yielding a pooled relative risk (RR) of 1.25 (95% confidence interval 1.15-1.35) for CVD comparing top (i.e. more severe) vs. bottom (less severe) third of endothelial dysfunction. There was significant between-study heterogeneity and evidence of publication bias. RRs varied importantly according to the method used to ascertain endothelial function, and were higher among older individuals and among participants with risk factors for CVD or established CVD at baseline.

CONCLUSIONS

Although endothelial dysfunction is an important determinant of cardiovascular outcomes in people with pre-existing CVD, current evidence base does not support its use as a potentially useful measurement for risk stratification in people at lower risk of CVD.

Secondary prevention strategy of cardiovascular disease using endothelial function testing

Over the past decades, secondary prevention of cardiovascular (CV) disease has improved and considerably reduced mortality rates. However, there remains a high-rate of new or recurrent CV events in those with established atherosclerotic vascular diseases. Although most of the prevailing therapies target the conventional risk factors, there is notable interindividual heterogeneity in adaptation to risk factors and response to therapies, which affects efficacy. It is desirable to have a methodology for directly assessing the functional significance of atherogenesis, and for managing individual patients based on their comprehensive vascular health. Endothelial function plays a pivotal role in all stages of atherosclerosis, from initiation to atherothrombotic complication. Endothelial function reflects the integrated effect of all the atherogenic and atheroprotective factors present in an individual, and is therefore regarded as an index of active disease process and a significant risk factor for future CV events. Moreover, improvement in endothelial function is associated with decreased risk of CV events, even in the secondary prevention setting. The introduction of endothelial function assessment into clinical practice may trigger the development of a more tailored and personalized medicine and improve patient outcomes. In this review, we summarize current knowledge on the contribution of endothelial dysfunction to atherosclerotic CV disease in the secondary prevention setting. Finally, we focus on the potential of an endothelial function-guided management strategy in secondary prevention.

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.

Effect of aliskiren on circulating endothelial progenitor cells and vascular function in patients with type 2 diabetes and essential hypertension

BACKGROUND

The aim of this study was to investigate the effects of aliskiren on vascular function and endothelial progenitor cells (EPCs) in patients with type 2 diabetes and essential hypertension.

METHODS

The study enrolled type 2 diabetic patients aged >50 years under stable glycemic control and first diagnosed mild essential hypertension. In phase A (n = 20), patients received aliskiren 150-300 mg daily for 3 months. In phase B (n = 12), hydrochlorothiazide (HCTZ) 12.5-25mg daily substituted for aliskiren for 3 more months. At baseline and at the end of each phase, we assessed (i) brachial blood pressure (BBP); (ii) central aortic systolic pressure (CSP), aortic augmentation index (Aix), and pulse wave velocity (PWV) as markers of arterial stiffness; (iii) brachial artery flow-mediated dilatation (FMD) as a marker of endothelial function; (iv) left ventricular (LV) twisting and untwisting as markers of LV function and (v) EPC numbers in culture of peripheral blood mononuclear cells.

RESULTS

Aliskiren similarly reduced BBP and CSP, increased FMD (P < 0.001) and EPC numbers (P < 0.001), decreased PWV and Aix (P < 0.05), and improved LV twisting and untwisting (P < 0.05). Although substitution of HCTZ sustained BBP at similar levels, CSP and echocardiographic indices nearly returned at baseline levels, and the improvement of FMD, PWV, Aix, and EPC numbers was abolished.

CONCLUSIONS

Aliskiren had a favorable effect on endothelial function and EPCs, reduced arterial stiffness, and improved LV twisting and untwisting. These effects were independent of BBP lowering, as they were not observed after the achievement of similar values of BBP with HCTZ.

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.

Endothelial dysfunction is associated with major adverse cardiovascular events in peritoneal dialysis patients

Endothelial dysfunction is implicated in increased cardiovascular risk in nondialyzed population. However, the prognostic impact of endothelial dysfunction on cardiovascular outcome has not been investigated in peritoneal dialysis (PD) patients. We prospectively determined endothelial function by brachial artery endothelium-dependent vasodilation (flow-mediated dilation [FMD]) in 143 nondiabetic PD patients and 32 controls. Primary outcome was a major adverse cardiac and cerebrovascular event (MACCE). Brachial FMD was significantly lower in PD patients than in controls (2.9% [1.3-4.7] vs 6.2% [5.4-8.3], P < 0.001). During a mean follow-up of 42 months, primary outcome was observed in 25 patients (17.5%). When patients were dichotomized by the median value of FMD (2.9%), incidence rates of MACCEs were significantly higher in the group with lower FMD compared with higher FMD (7.2 vs 3.0/100 person-years, P = 0.03). In multivariate Cox analysis, low FMD (≤2.9%) was a significant independent predictor of MACCEs (hazard ratio = 2.73, 95% confidence interval = 1.03-7.22, P = 0.04). Furthermore, multivariate fractional polynomial analysis showed that the risk of MACCE decreased steadily with higher FMD values. Impaired brachial FMD was a significant independent predictor of MACCEs in PD patients. Estimating endothelial dysfunction by brachial FMD could be useful for stratifying cardiovascular risk in these patients.

Endothelial dysfunction in metabolic and vascular disorders

Vascular endothelium has important regulatory functions in the cardiovascular system and a pivotal role in the maintenance of vascular health and metabolic homeostasis. It has long been recognized that endothelial dysfunction participates in the pathogenesis of atherosclerosis from early, preclinical lesions to advanced, thrombotic complications. In addition, endothelial dysfunction has been recently implicated in the development of insulin resistance and type 2 diabetes mellitus (T2DM). Considering that states of insulin resistance (eg, metabolic syndrome, impaired fasting glucose, impaired glucose tolerance, and T2DM) represent the most prevalent metabolic disorders and risk factors for atherosclerosis, it is of considerable scientific and clinical interest that both metabolic and vascular disorders have endothelial dysfunction as a common background. Importantly, endothelial dysfunction has been associated with adverse outcomes in patients with established cardiovascular disease, and a growing body of evidence indicates that endothelial dysfunction also imparts adverse prognosis in states of insulin resistance. In this review, we discuss the association of insulin resistance and T2DM with endothelial dysfunction and vascular disease, with a focus on the underlying mechanisms and prognostic implications of the endothelial dysfunction in metabolic and vascular disorders. We also address current therapeutic strategies for the improvement of endothelial dysfunction.

A meta-analysis of randomized controlled trials of telmisartan for flow-mediated dilatation

There have been a number of small-sized underpowered randomized controlled trials to assess effects of telmisartan on flow-mediated dilatation (FMD). To determine whether telmisartan increases FMD, we performed a meta-analysis of these trials. MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched through December 2013. Eligible studies were prospective randomized controlled trials of telmisartan reporting FMD as an outcome. Search terms included: telmisartan; endothelial function/dysfunction; flow-mediated dilation/dilatation/vasodilation/vasodilatation; and randomized, randomly or randomization. Included studies were reviewed to determine the number of patients randomized, mean duration of treatment and percent changes of FMD. Of 25 potentially relevant articles screened initially, seven reports of randomized trials enrolling a total of 398 patients were identified and included. A pooled analysis of the seven trials demonstrated a statistically significant increase in FMD by 48.7%, with telmisartan relative to control in the random-effects model (mean difference, 48.72%; 95% confidence interval, 15.37-82.08%; P for effect=0.004; P for heterogeneity <0.00001). Exclusion of any single trial from the analysis did not substantively alter the overall result of our analysis. There was no evidence of significant publication bias. In conclusion, the present meta-analysis of seven randomized controlled trials enrolling a total of 398 patients confirmed the evidence of a significant increase in FMD with telmisartan, which suggests that telmisartan may improve endothelial dysfunction.

Brachial artery endothelial responses during early recovery from an exercise bout in patients with coronary artery disease

This study examined the acute endothelial responses to an exercise bout in coronary artery disease (CAD) patients. Nineteen males with CAD (63 ± 8 years) were assessed at rest and 15 minutes following a submaximal exercise bout (recovery). Brachial artery endothelial-dependent function was assessed using flow-mediated dilation (FMD). Brachial artery diameters and velocities were measured using Duplex ultrasound at baseline, and for 3 minutes following a 5-minute ischemic period. Endothelial-independent function was assessed using a 0.4 mg dose of nitroglycerin (NTG). FMD responses were unchanged from rest to recovery; however, there were 2 types of responses: negative and positive FMD responders. Post-hoc analysis revealed that positive responders had lower resting FMD compared to negative responders (3.2 ± 1.7 versus 6.0 ± 2.5%, P < 0.05). NTG-mediated dilation was reduced in recovery (22.0 ± 5.6 versus 14.4 ± 5.7%, P < 0.001 for rest versus recovery). In conclusion, acute endothelial-dependent responses to submaximal exercise are affected by the degree of resting endothelial dysfunction. The observation of attenuated NTG-mediated dilation during recovery is novel and warrants the investigation of possible mechanisms and clinical significance. Furthermore, it highlights the necessity of both endothelial-dependent and endothelial-independent assessments when evaluating endothelial function changes with an intervention.

Arterial injury and endothelial repair: rapid recovery of function after mechanical injury in healthy volunteers

Objective. Previous studies suggest a protracted course of recovery after mechanical endothelial injury; confounders may include degree of injury and concomitant endothelial dysfunction. We sought to define the time course of endothelial function recovery using flow-mediated dilation (FMD), after ischaemia-reperfusion (IR) and mechanical injury in patients and healthy volunteers. The contribution of circulating CD133⁺/CD34⁺/VEGFR2⁺ “endothelial progenitor” (EPC) or repair cells to endothelial repair was also examined. Methods. 28 healthy volunteers aged 18–35 years underwent transient forearm ischaemia induced by cuff inflation around the proximal biceps and radial artery mechanical injury induced by inserting a wire through a cannula. A more severe mechanical injury was induced using an arterial sheath and catheter inserted into the radial artery of 18 patients undergoing angiography. Results. IR and mechanical injury produced immediate impairment of FMD (from 6.5 ± 1.2% to 2.9 ± 2.2% and from 7.4 ± 2.3% to 1.5 ± 1.6% for IR and injury, resp., each P < 0.001) but recovered within 6 hours and 2 days, respectively. FMD took up to 4 months to recover in patients. Circulating EPC did not change significantly during the injury/recovery period in all subjects. Conclusions. Recovery of endothelial function after IR and mechanical injury is rapid and not associated with a change in circulating EPC.

Non-invasive endothelial function testing and the risk of adverse outcomes: a systematic review and meta-analysis

OBJECTIVES

We performed a systematic review and meta-analysis to understand the role of flow-mediated dilatation (FMD) of the brachial artery (BA) and peripheral arterial tonometry (PAT) in predicting adverse events, including cardiovascular (CV) events and all-cause mortality.

BACKGROUND

FMD of the BA and PAT are non-invasive measures of endothelial function. Impairment of endothelial function is associated with increased CV events. While FMD is the more widely used and studied technique, PAT offers several advantages. The purpose of this systematic review and meta-analysis is to determine whether brachial FMD and PAT are independent risk factors for future CV events and mortality.

METHODS

Multiple electronic databases were searched for articles relating FMD or PAT to CV events. Data were extracted on study characteristics, study quality, and study outcomes. Relative risks (RRs) from individual studies were combined and a pooled multivariate RR was calculated.

RESULTS

Thirty-six studies for FMD were included in the systematic review, of which 32 studies consisting of 15, 191 individuals were meta-analysed. The pooled RR of CV events and all-cause mortality per 1% increase in brachial FMD, adjusting for potential confounders, was 0.90 (0.88-0.92). In contrast, only three studies evaluated the prognostic value of PAT for CV events, and the pooled RR per 0.1 increase in reactive hyperaemia index was 0.85 (0.78-0.93).

CONCLUSION

Brachial FMD and PAT are independent predictors of CV events and all-cause mortality. Further research to evaluate the prognostic utility of PAT is necessary to compare it with FMD as a non-invasive endothelial function test in clinical practice.

Prognostic value of peripheral arterial tonometry in patients with coronary artery disease and a high cardiovascular risk profile

AIM

Data regarding the prognostic value of peripheral endothelial function testing in patients with cardiovascular disease are conflicting. Peripheral arterial tonometry(PAT) is increasingly used to measure the peripheral endothelial function. The prognostic value of this method has not been investigated thus far in patients with cardiovascular disease and/or a high cardiovascular risk profile.

METHODS

In 96 patients with significant coronary artery disease(CAD) or＜70% stenosis and ≥ three cardiovascular risk factors, reactive hyperemia was induced following upper arm occlusion and the PAT-ratio between baseline and hyperemia was calculated. The patients were followed for cardiovascular events(revascularization, acute coronary syndrome, ischemic stroke, cardiovascular death, repeat coronary angiography due to chest pain) for 44±14 months. The first event was included in the combined end point.

RESULTS

The study cohort was divided according to the median PAT-ratio(1.91). The combined end point occurred in 14 patients with a PAT-ratio below the median(1.91) and in 12 patients with a PAT-ratio of ≥1.91 (p=0.65). In a subgroup of 76 patients, the PAT-ratio was reassessed after six months. No differences in the event rate were found between the patients who exhibited deterioration(n=50) and those who exhibited an improvement in the PAT-ratio of ＞0.1(n=26; 22 vs. 32%, p=0.32). The combined end point occurred earlier in the patients with a PAT-ratio within the 1st tertile than in those with a PAT-ratio within the 2nd/3rd tertile(11.3±11.0 vs. 27.5±18.6 months, p=0.03).

CONCLUSIONS

In patients with established CAD or a high cardiovascular risk profile, the PAT-ratio cannot be used to predict the risk of future cardiovascular events. However, a lower PAT-ratio may be associated with the earlier occurrence of cardiovascular events.

Vitamin D deficiency, interleukin 17, and vascular function in rheumatoid arthritis

OBJECTIVE

Vitamin D deficiency is associated with increased cardiovascular (CV) disease risk in the general population. We examined the association between vitamin D deficiency and CV risk in rheumatoid arthritis (RA).

METHODS

We measured large artery compliance by pulse wave velocity and microvascular function by the reactive hyperemia index in patients with stable RA (n = 87). We quantified CV risk factors, serum 25-hydroxyvitamin D [25(OH)D], and interleukin 17 (IL-17), and RA disease activity by Disease Activity Score of 28 joints. We used linear regression to test associations between serum 25(OH)D and CV risk factors.

RESULTS

The mean serum 25(OH)D level in the cohort was 27.1 ± SD 13.6 ng/ml. Fifty-nine patients (68%) were vitamin D-insufficient (25(OH)D < 30 ng/ml; mean 20.2 ± 5.9 ng/ml) and of these, 25 (29%) were vitamin D-deficient (25(OH)D < 20 ng/ml; mean 14.4 ± 3.4 ng/ml). In the whole cohort and the vitamin D-insufficient group, serum 25(OH)D was inversely associated with IL-17 (log IL-17; β = -0.83, p = 0.04; β = -0.63, p = 0.004, respectively) by univariate analysis, which persisted after adjustment for season, and in multivariate analysis after adjustment for confounders (log IL-17; β = -0.74, p = 0.04; β = -0.53, p = 0.02). In vitamin D-deficient patients, serum 25(OH)D was positively associated with microvascular function by univariate and multivariate analysis after adjustment for confounders (β = 2.1, p = 0.04; β = 2.7, p = 0.04).

CONCLUSION

Vitamin D deficiency in RA may affect Th17 responses and microvascular function. Maintaining normal serum vitamin D levels may protect against IL-17-mediated inflammation and vascular dysfunction in RA.

The impact of acute mental stress on vascular endothelial function: evidence, mechanisms and importance

Cardiovascular disease is a principle cause of morbidity and mortality worldwide, and it has a complex etiology that involves lifestyle factors such as psychosocial stress. Recent evidence suggests that temporary impairments in vascular endothelial cell function may contribute to the relationship between stress and cardiovascular disease. Indeed, impaired endothelial function has been observed to occur transiently (lasting up to 1.5h) following mental stress, and such periods of impairment could accumulate to become clinically relevant over the long term. The finding of acute stress induced endothelial dysfunction is not universal however, and both physiological (e.g. sympathetic nervous system and hypothalamic-pituitary-adrenal axis reactivity), and methodological factors contribute to the conflicting results. A clear understanding of the interaction between stress response activation and endothelial function is critical to elucidating the complexities of the relationship between psychosocial stress and cardiovascular disease. Therefore, the purpose of this review is: 1) to briefly describe the importance of vascular endothelial function and how it is assessed, 2) to review the literature investigating the impact of acute mental stress on endothelial function in humans, identifying factors that may explain contradictory results, and 3) to summarize our current understanding of the mechanisms that may mediate an acute mental stress-endothelial function interaction.

Flow-mediated dilation normalization predicts outcome in chronic heart failure patients

BACKGROUND

Reduced flow-mediated dilation (FMD) is a known prognostic marker in heart failure (HF), but may be influenced by the brachial artery (BA) diameter. Aiming to adjust for this influence, we normalized FMD (nFMD) by the peak shear rate (PSR) and tested its prognostic power in HF patients.

METHODS AND RESULTS

BA diameter, FMD, difference in hyperemic versus rest brachial flow velocity (FVD), PSR (FVD/BA), and nFMD (FMD/PSR × 1000) were assessed in 71 HF patients. At follow-up (mean 512 days), 19 HF (27%) reached the combined endpoint (4 heart transplantations [HTs], 1 left ventricle assist device implantation [LVAD], and 14 cardiac deaths [CDs]). With multivariate Cox regression analysis, New York Heart Association functional class ≥III (hazard ratio [HR] 9.36, 95% confidence interval [CI] 2.11-41.4; P = .003), digoxin use (HR 6.36, 95% CI 2.18-18.6; P = .0010), FMD (HR 0.703, 95% CI 0.547-0.904; P = .006), PSR (HR 1.01, 95% CI 1.005-1.022; P = .001), FVD (HR 1.04, 95% CI 1.00-1.06; P = .02), and nFMD (HR 0.535, 95% CI 0.39-0.74; P = .0001) were predictors of unfavorable outcome. Receiver operating characteristic curve for nFMD showed that patients with nFMD >5 seconds had significantly better event-free survival than patients with nFMD ≤5 seconds (log-rank test: P < .0001).

CONCLUSIONS

nFMD is a strong independent predictor of CD, HT, and LVAD in HF with left ventricular ejection fraction <40%. Patients with nFMD >5 seconds have a better prognosis than those with lower values.

Comparison of brachial artery wall thickness versus endothelial function to predict late cardiovascular events in patients undergoing elective coronary angiography

An increased brachial artery intima media thickness (BA-IMT) has been shown to be of prognostic value. Conflicting prognostic data have been reported for brachial artery flow-mediated vasodilation (BA-FMD), and the longest evaluated follow-up period to date is 5.5 years. We sought to investigate the very late prognostic value of BA-IMT and BA-FMD in 396 consecutive patients (age 54 ± 9 years) admitted for invasive evaluation of chest pain. BA-IMT and BA-FMD were measured using high-resolution ultrasonography. The patients were divided according to the median BA-IMT (0.37 mm) and median BA-FMD (7.6%). After a mean follow-up of 141 ± 12 months, cardiovascular events were documented. More cardiovascular events were found in patients with an increased BA-IMT (50 vs 78 events, p = 0.003). When the groups were compared according to the median BA-FMD, no differences in the number of events were documented (70 vs 75 events, p = 0.60). On multivariate Cox regression analysis, including age, number of risk factors, BA diameter, presence of coronary artery disease, BA-FMD, and BA-IMT, only the presence of coronary artery disease and BA-IMT remained significantly associated with outcome. In conclusion, BA-IMT, but not BA-FMD, predicted cardiovascular events and cardiovascular death with ≤12 years of follow-up in patients undergoing an invasive evaluation of chest pain. Our results represent, by far, the longest follow-up of BA-IMT and peripheral endothelial function testing compared with previously reported data.

Pleiotropic preventive effects of dietary polyphenols in cardiovascular diseases

Polyphenols are common constituents of the diet, and research on their health benefits has developed quickly over the past few years. Our purpose is to review recent findings highlighting daily dietary polyphenol intake and the diverse function of polyphenols and their possible relationships to cardiovascular disease (CVD). Several cohort studies have reported an inverse relationship between the daily consumption of polyphenols and CVD risk. Many studies showed that beverages could be a large source of polyphenols. Our previous findings provide that Japanese people intake polyphenols mainly from beverages, especially coffee and green tea (in descending order of polyphenol content). Many kinds of polyphenols act as an antioxidant against low-density lipoprotein oxidation, which is known to promote atherosclerosis. Recent accumulating evidence suggests that dietary polyphenols could exert their cardioprotective actions through their potential to improve metabolic disorder and vascular inflammation. These findings raise the possibility that polyphenols have a wide variety of roles in the intestine, liver and vascular tissue. In addition to identifying mechanisms of polyphenol bioactivity by basic research, much more epidemiological and clinical evidence linking reduced cardiovascular risk with dietary polyphenols intake are needed.

Clinical correlates and prognostic value of flow mediated dilation in patients with non-ST segment elevation acute coronary syndromes

Endothelial dysfunction can predict cardiovascular outcomes in several populations of patients. The aim of this study was to assess the severity, time course, and clinical implications of endothelial dysfunction in patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). Sixty patients with NSTE ACS (mean age 62 ± 8 years, 44 men) and 40 controls with stable coronary artery disease (CAD) (mean age 63 ± 10 years, 27 men) were studied. In patients with NSTE ACS and in those with stable CAD, endothelial function was assessed <12 hours after admission and at 3-month follow-up by measuring right brachial artery dilation after 5 minutes of forearm ischemia (flow-mediated dilation [FMD]). Clinical outcomes were assessed after a median follow-up period of 32 months (range 14 to 36). The primary end point was a combination of cardiac death or readmission for new ACS or recurrence of angina pectoris. FMD on admission was significantly lower in patients with NSTE ACS compared to those with stable CAD (2.1 ± 1.2% vs 4.8 ± 1.9%, p <0.001). FMD improved significantly at 3-month follow-up in patients with NSTE ACS, becoming comparable to that in patients with stable CAD (5.7 ± 2.6% vs 5.5 ± 1.7%, p = 0.93). During follow-up, 14 cardiac events (23%) occurred in patients with NSTE ACS. On multivariate analysis, only diabetes (hazard ratio 18.1, 95% confidence interval 3.9 to 83.9, p <0.001) and FMD at 3 months (hazard ratio 0.78, 95% confidence interval 0.61 to 0.99, p = 0.04) were independent predictors of the primary end point in patients with NSTE ACS. In conclusion, endothelial function is markedly impaired in the acute phase of NSTE ACS but improves significantly at 3-month follow-up. In patients with NSTE ACS, FMD at 3 months after the acute event is a significant independent predictor of cardiac outcomes.

Flow-mediated dilation and cardiovascular risk prediction: a systematic review with meta-analysis

BACKGROUND

Flow-mediated dilation (FMD) is an accepted technique to quantify endothelial function and has shown to have prognostic value for future cardiovascular disease (CVD). The predictive strength of FMD in CVD patients compared to populations not diagnosed for CVD warrants further investigation. We systematically reviewed prospective studies that investigated the association between brachial FMD and future cardiovascular events, with particular focus on the role of underlying health status.

METHODS

To obtain eligible studies, several literature databases were systematically searched through March 2011. Pooled overall risk estimates were calculated separately for continuous risk estimates for CVD (per 1% higher FMD) and for categorical risk estimates for CVD (having high vs. low FMD), based on random-effects models.

RESULTS

A total of 23 studies including 14,753 subjects were eligible for inclusion in the meta-analysis. For studies reporting continuous risk estimates, the pooled overall CVD risk was 0.92 (95%CI: 0.88; 0.95) per 1% higher FMD. The observed association seemed stronger (P-value<0.01) in diseased populations than in asymptomatic populations (0.87 (95%CI: 0.83; 0.92) and 0.96 (95%CI: 0.92; 1.00) per 1% higher FMD, respectively). For studies reporting categorical risk estimates, the pooled overall CVD risk for high vs. low FMD was similar in both types of populations, on average 0.49 (95%CI: 0.39; 0.62).

CONCLUSIONS

Our findings show that brachial FMD is inversely associated with future CVD events, with some indications for a stronger relation in diseased populations. Endothelial dysfunction may be considered relevant for classifying subjects in terms of CVD risk.

Effect of cocoa/chocolate ingestion on brachial artery flow-mediated dilation and its relevance to cardiovascular health and disease in humans

Prospective studies indicate that high intake of dietary flavanols, such as those contained in cocoa/chocolate, are associated with reduced rates of cardiovascular-related morbidity and mortality in humans. Numerous mechanisms may underlie these associations such as favorable effects of flavanols on blood pressure, platelet aggregation, thrombosis, inflammation, and the vascular endothelium. The brachial artery flow-mediated dilation (FMD) technique has emerged as a robust method to quantify endothelial function in humans. Collectively, the preponderance of evidence indicates that FMD is a powerful surrogate measure for firm cardiovascular endpoints, such as cardiovascular-related mortality, in humans. Thus, literally thousands of studies have utilized this technique to document group differences in FMD, as well as to assess the effects of various interventions on FMD. In regards to the latter, numerous studies indicate that both acute and chronic ingestion of cocoa/chocolate increases FMD in humans. Increases in FMD after cocoa/chocolate ingestion appear to be dose-dependent such that greater increases in FMD are observed after ingestion of larger quantities. The mechanisms underlying these responses are likely diverse, however most data suggest an effect of increased nitric oxide bioavailability. Thus, positive vascular effects of cocoa/chocolate on the endothelium may underlie (i.e., be linked mechanistically to) reductions in cardiovascular risk in humans.