Endothelial dysfunction in type 2 diabetic patients with normal coronary arteries: a digital reactive hyperemia study

A stronger association of diabetes mellitus with impaired hyperaemia using a novel ECG-gated device compared with peripheral arterial tonometry

PURPOSE

Impaired digital reactive hyperaemia and flicker-stimulated retinal vascular response are commonly reported risk markers of cardiovascular disease. This is the first study to determine the correlation of these risk markers with diabetes mellitus by comparing our novel flicker-modulated ECG-gated fundoscope with the EndoPAT2000 system.

METHODS

In total, 119 controls and 120 participants with diabetes mellitus partook in this cross-sectional study. The EndoPAT2000 system assessed digital reactive hyperaemia under fasting conditions. A mydriatic ECG-gated fundoscope with a novel flicker module acquired digital retinal images of the left eye before, during and after flicker stimulation. An inhouse semi-automated software measured retinal vessel diameters using a validated protocol with two observers repeating measurements in a subset of 10 controls and 10 participants with diabetes mellitus. Intra- and inter-observer reliability analyses occurred by the interclass correlation coefficient. A receiver operating characteristic curve established associations of variables with diabetes mellitus.

RESULTS

Diabetes mellitus was more strongly associated with flicker-stimulated retinal arteriolar calibre change from baseline (AUC 0.81, 95% CI 0.75-0.87, p < 0.0001) than reactive hyperaemia index. Median flicker-stimulated arteriolar calibre change from baseline (controls: 2.74%, IQR 1.07 vs diabetes mellitus: 1.64%, IQR 1.25, p < 0.0001) and reactive hyperaemia index (controls: 1.87, IQR 0.81 vs diabetes mellitus: 1.60, IQR 0.81, p = 0.003) were lower in diabetes mellitus than controls. Intra- and inter-observer reliability coefficients were high from 0.87 to 0.93.

CONCLUSIONS

Impaired flicker-stimulated retinal arteriolar calibre change from baseline is more highly correlated with diabetes mellitus in this study than a reduced reactive hyperaemia index.

Low physical activity is associated with impaired endothelial function in patients with type 2 diabetes and controls after 5 years of follow-up

BACKGROUND

The long-term association between physical activity and endothelial function has not previously been investigated in patients with type 2 diabetes. Therefore, we aimed to evaluate the relationship between physical activity and endothelial function, assessed by peripheral arterial tonometry, in patients with type 2 diabetes and non-diabetic controls after 5 years of follow-up.

METHODS

We included 51 patients with newly diagnosed type 2 diabetes and 53 sex- and age matched controls. Participants underwent baseline clinical characterization including objective measurement of physical activity level using accelerometery. After 5 years of follow-up, participants were re-examined, and endothelial function was assessed as natural logarithm of reactive hyperemia index (lnRHI).

RESULTS

Physical activity at baseline was associated with lnRHI after 5 years of follow-up in both patients with type 2 diabetes and controls. An increase of 1 standard deviation (SD) in daytime physical activity corresponded to a 6.7 % increase in RHI (95 % confidence interval: 1.1;12.5 %, p = 0.02). We found no difference in lnRHI between patients with diabetes and controls (0.67 ± 0.29 vs. 0.73 ± 0.31, p = 0.28).

CONCLUSIONS

Daytime physical activity is associated with endothelial function after 5 years of follow-up in patients with type 2 diabetes and controls.

Association between lipid profile and endothelial dysfunction as assessed by the reactive hyperemia index

INTRODUCTION

We investigated the associations between endothelial dysfunction (ED) as evaluated by the reactive hyperemia index (RHI) obtained using Endo-PAT2000® and atherosclerotic risk factors in patients who underwent coronary artery angiography (CAG).

METHODS

The subjects consisted of 191 patients who were clinically suspected to have CAD and underwent CAG, and in whom we could perform Endo-PAT2000®. We divided the patients into ED (RHI<1.67, n = 71) and non-ED (RHI≥1.67, n = 120) groups.

RESULTS

The ED group was significantly older and showed a higher ratio of low-density lipoprotein cholesterol (LDL-C) to high-density lipoprotein cholesterol (HDL-C) (L/H) than the non-ED group. A multivariate logistic regression analysis was performed to examine the associations between the presence of ED and age, gender, and BMI in addition to L/H. Age [odds ratio (OR) = 1.03, p = .02] and L/H (OR = 1.64, p = .01) were identified as significant independent markers of the presence of ED. Next, we divided 122 patients with statin treatment into ED (n = 40) and non-ED (n = 82) groups. The ED group tended to have higher L/H and lower HDL-C than the non-ED group. HDL-C (OR = 0.95, p = .01) and age (OR = 1.05, p = .04) were identified as independent markers of the presence of ED.

CONCLUSIONS

L/H was an independent marker of the presence of ED in patients without dyslipidemia. In addition, among patients with statin treatment, HDL-C was an independent marker of the presence of ED.

The metabolic syndrome in heart failure: insights to specific mechanisms

The presence of comorbidities significantly influences long-term morbidity and mortality of symptomatic and asymptomatic heart failure (HF) patients. Metabolic syndrome and diabetic cardiomyopathy are two clinical conditions that share multiple pathophysiological mechanisms and that might be both responsible for cardiac dysfunction. However, it is argued whether metabolic syndrome (MS) independently increases HF risk or the association between MS and HF merely reflects the impact of individual risk factors included in its definition on HF development. Similarly, in the context of diabetic cardiomyopathy, many aspects are still challenging starting from the definition up to the therapeutic management. In this clinical review, we focused the attention on molecular pathways, myocyte alterations, and specific patterns of metabolic syndrome and diabetic cardiomyopathy in order to better define the potential diagnostic and therapeutic approaches of these two pathological conditions.

Peripheral arterial endothelial dysfunction predicts future cardiovascular events in diabetic patients with albuminuria: a prospective cohort study

Background

Reactive hyperemia-peripheral arterial tonometry (RH-PAT) is a noninvasive and simple test for evaluating the endothelial function. There has been sparse evidence on the usefulness of the RH-PAT index (RHI) in predicting future cardiovascular diseases among diabetic patients.

Methods

Asymptomatic diabetic patients with albuminuria were selected; their medical history and laboratory findings were evaluated every 3 to 4 months, respectively. The primary outcome was a composite of three-point major adverse cardiovascular events (3-point MACE): death from cardiovascular causes, acute coronary events, or nonfatal stroke. On the contrary, secondary outcomes included a composite of 3-point MACE, hospitalization for heart failure, or chronic kidney disease (CKD) progression. RHI was measured using the Endo-PAT2000 at the baseline. RHI < 1.67 was considered to indicate peripheral endothelial dysfunction (PED).

Results

In total, 149 subjects were included (mean age, 61.8 ± 9.2 years; duration of diabetes was 12 years). During the follow-up period (median, 49.7 months), of the 149 subjects, primary outcomes were detected in 12 (1 [2.3%] and 11 [10.5%] of those without and with PED, respectively). The presence of PED in baseline measurements significantly increased both primary and secondary outcomes, following adjustment for age, sex, hypertension, glycated hemoglobin, low-density lipoprotein cholesterol, triglyceride, systolic blood pressure, baseline estimated glomerular filtration rate, overt proteinuria, duration of diabetes, premedical history of ischemic events, anti-platelet agents, and smoking history (hazard ratio [HR]: 10.95; 95% confidence interval CI 1.00–119.91 for the primary outcome; HR, 4.12; 95% CI 1.37–12.41 for secondary outcome). In addition, PED could predict secondary outcomes independent of the risk score according to the American College of Cardiology/American Heart Association (HR: 3.24; 95% CI 1.14–9.17).

Conclusions

PED can independently predict future cardiovascular events among diabetic patients with albuminuria.

Measurement of peripheral arterial tonometry in patients with diabetic foot ulcers during courses of hyperbaric oxygen treatment

INTRODUCTION

Treatment of diabetic foot ulcers is complex and often protracted. Hyperbaric oxygen treatment (HBOT) improves wound healing in diabetic ulcers and serves as an important adjunct to regular diabetic wound care. Endothelial dysfunction plays a central role in diabetes-related vascular complications and may be evaluated by a non-invasive technique called peripheral arterial tonometry which measures a reactive hyperaemia index (RHI). We hypothesized that endothelial function measured by peripheral arterial tonometry is impaired in diabetic foot ulcer patients and that HBOT might improve endothelial function.

METHODS

Endothelial function was prospectively assessed by peripheral arterial tonometry in 22 subjects with diabetic foot ulcers and 17 subjects without diabetes during courses of HBOT. Endothelial function was evaluated before first (baseline) and 30th treatments, and at 90-day follow-up. Serum insulin growth factor-I (IGF-I) concentrations were determined by immunoassay. Results were compared to 23 healthy subjects.

RESULTS

No baseline differences were found in endothelial function between subjects with diabetes, HBOT patients without-diabetes and healthy control subjects (RHI; 1.26, 1.61 and 1.81, respectively). No significant changes in RHI were found in patients with (P = 0.17) or without (P = 0.30) diabetes during courses of HBOT. At 90-day follow-up IGF-I was significantly reduced in the subjects with diabetes (P = 0.001) and unchanged in the group without diabetes (P = 0.99).

CONCLUSIONS

We found no significant differences in RHI between subjects with diabetic foot ulcers and patients without diabetes, nor improvement in endothelial function assessed by peripheral arterial tonometry during courses of HBOT.

Prognostic Value of Hormonal Abnormalities in Heart Failure Patients

The model used to explain the pathophysiologic substrate and progressive worsening in chronic heart failure (CHF) is based on the hyperactivity of renin-angiotensin-aldosterone system and adrenergic pathway. Although the neurohormonal medical approach has many advantages, it has several pitfalls, as demonstrated by high rates of CHF mortality and hospitalization. A growing body of evidence has led to the hypothesis that CHF is a multiple hormone deficiency syndrome, characterized by a reduced anabolic drive that has relevant functional and prognostic implications. The aim of this review is to summarize the evidence of reduced drive of main anabolic axes in CHF.

Diabetic Cardiomyopathy: Definition, Diagnosis, and Therapeutic Implications

A strict bidirectional relationship exists between diabetes mellitus and heart failure. Diabetic cardiomyopathy is a specific cardiac manifestation of patients with diabetes characterized by left ventricular hypertrophy and diastolic dysfunction in the early phase up to overt heart failure with reduced systolic function in the advanced stages. The pathogenesis of this condition is multifactorial and recognizes as main promoting factors the presence of insulin resistance and hyperglycemia. Diabetic cardiomyopathy exerts a negative prognostic impact in affected patients and no target treatments are currently available. More efforts are needed to better define the diagnostic and therapeutic approach in this specific setting.

Sympathoexcitation constrains vasodilation in the human skeletal muscle microvasculature during postocclusive reactive hyperemia

We used diffuse correlation spectroscopy to investigate sympathetic vasoconstriction, local vasodilation, and integration of these two responses in the skeletal muscle microvasculature of 20 healthy volunteers. Diffuse correlation spectroscopy probes were placed on the flexor carpi radialis muscle or vastus lateralis muscle, and a blood flow index was derived continuously. We measured hemodynamic responses during sympathoexcitation induced by forehead cooling, after which the effects of the increased sympathetic tone on vasodilatory responses during postocclusive reactive hyperemia (PORH) were examined. PORH was induced by releasing arterial occlusion (3 min) in an arm or leg. To increase sympathetic tone during PORH, forehead cooling was begun 60 s before the occlusion release and ended 60 s after the release. During forehead cooling, mean arterial pressure rose significantly and was sustained at an elevated level. Significant vasoconstriction and decreases in blood flow index followed by gradual blunting of the vasoconstriction also occurred. The time course of these responses is in good agreement with previous observations in animals. The acute sympathoexcitation diminished the peak vasodilation during PORH only in the vastus lateralis muscle, but it hastened the decline in vasodilation after the peak in both the flexor carpi radialis muscle and vastus lateralis muscle. Consequently, the total vasodilatory response assessed as the area of the vascular conductance during the first minute of PORH was significantly diminished in both regions. We conclude that, in humans, the integrated effects of sympathetic vasoconstriction and local vasodilation have an important role in vascular regulation and control of perfusion in the skeletal muscle microcirculation.

NEW & NOTEWORTHY We used diffuse correlation spectroscopy to demonstrate that acute sympathoexcitation constrains local vasodilation in the human skeletal muscle microvasculature during postocclusive reactive hyperemia. This finding indicates that integration of sympathetic vasoconstriction and local vasodilation is importantly involved in vascular regulation and the control of perfusion of the skeletal muscle microcirculation in humans.

Ethnic Disparities in Endothelial Function and Its Cardiometabolic Correlates: The Pathobiology of Prediabetes in A Biracial Cohort Study

BACKGROUND

Endothelial function (EF) reflects the balance between vasodilatory and vasoconstrictive factors produced by (or acting on) the innermost lining of blood vessels. Endothelial dysfunction, an imbalance between these factors that favors vasoconstriction, has been associated with increased risk for cardiovascular disease. However, the influence of race/ethnicity and glycemic status on association between EF and cardiovascular risk factors remain to be clarified.

SUBJECTS AND METHODS

We assessed EF in relation to glycemia and cardiometabolic profile in African-American (AA) and European-American (EA) offspring of parents with type 2 diabetes (T2D), who are participants in the prospective pathobiology and reversibility of prediabetes in a biracial cohort (PROP-ABC) study. Assessments at enrollment included a 75 g oral glucose tolerance test (OGTT), blood pressure, anthropometry, body composition (DEXA), and lipid profile. Other assessments were insulin sensitivity and resting energy expenditure. EF was measured using flow-mediated vasodilation (EndoPAT 2000) and expressed as reactive hyperemia index (RHI).

RESULTS

We studied 190 subjects (100 AA, 90 C), mean age (±SD) 53.1 ± 9.1 years, and body mass index 30.6 ± 6.8 kg/m2. Based on OGTT data, 96 subjects (52 AA, 44 EA) had prediabetes and 94 subjects were normoglycemic (48 AA and 46 EA). The RHI was lower in AA than EA (2.17 ± 0.55 vs. 2.36 ± 0.72, P = 0.05) and in prediabetic than normoglycemic subjects (2.14 ± 0.62 vs. 2.38 ± 0.65, P = 0.013). Using RHI ≤ 1.68 as diagnostic cut-off, 19% of participants with prediabetes and 10% of normoglycemic participants had endothelial dysfunction (P = 0.04). In univariate models, RHI was positively associated with age and HDL cholesterol levels, and inversely associated with adiposity, diastolic blood pressure, and 2hr plasma glucose. The association between RHI and adiposity was stronger in men than women. The association between RHI and age, glucose and HDL cholesterol displayed marked ethnic disparities.

CONCLUSION

In our biracial cohort comprising offspring of parents with T2D, prediabetes increased the risk of endothelial dysfunction. However, the association between EF and cardiometabolic risk factors was significantly modified by ethnicity and gender. Our findings support current understanding of endothelial dysfunction as an early sensitive indicator of cardiometabolic risk.

Association between obstructive sleep apnea severity and endothelial dysfunction in patients with type 2 diabetes

Background

Obstructive sleep apnea (OSA) and type 2 diabetes (T2D) are associated with endothelial dysfunction a main predictor of late cardiovascular (CV) events. Despite the high prevalence of OSA in patients with T2D, the impact of OSA severity on endothelial function has not been clearly elucidated. The aim of this cross-sectional study was to determine whether increasing OSA severity is associated with poorer endothelial function in patients with T2D.

Methods

140 patients with T2D and no overt CV disease underwent polysomnography, peripheral arterial tonometry, clinic blood pressure (BP) measurement, biological assessment for CV risk factors, daytime sleepiness and health related quality of life (HRQL) questionnaires. The following commonly used cut-offs for apnea-hypopnea index (AHI) were used to define 3 categories of disease severity: AHI < 15 (no OSA or mild OSA), 15 ≤ AHI < 30 (moderate OSA), and AHI ≥ 30 (severe OSA). The primary outcome was the reactive hyperemia index (RHI), a validated assessment of endothelial function.

Results

21.4% of patients had moderate OSA and 47.6% had severe OSA. Increasing OSA severity and nocturnal hypoxemia were not associated with a significant decrease in RHI. Endothelial dysfunction (RHI < 1.67) was found in 47.1, 44.4 and 39.2% of patients with no OSA or mild OSA, moderate OSA and severe OSA, respectively (p = 0.76). After adjustment for confounders including body mass index, increasing OSA severity was associated with higher systolic BP (p = 0.03), lower circulating levels of adiponectin (p = 0.0009), higher levels of sP-selectin (p = 0.03), lower scores in 3 domains of HRQL including energy/vitality (p = 0.02), role functioning (p = 0.01), and social functioning (p = 0.04).

Conclusions

Moderate to severe OSA is very common but has no impact on digital micro-vascular endothelial function in patients with T2D.

Clinical Phenotype and Microvascular Dynamics of Subjects with Endothelial Dysfunction as Assessed by Peripheral Tonometry

OBJECTIVE

To evaluate the characteristics and the determinants of ED, as measured by PAT.

METHODS

We measured basal and post-ischemic digital pulse amplitude (EndoPAT(®)) in a mixed outpatient population of 206 diabetic and 101 non-diabetic subjects, of whom 50% with clinically manifest CVD, undergoing to an extensive clinical, biochemical, and vascular phenotype characterization.

RESULTS

The major characteristics of ED (tertile 1 vs 3), in addition to lower post-ischemic vasodilatory reserve (34 vs 203%), were a 3-fold higher baseline pulse amplitude and a delayed (60 second) peak response. The main determinant of this response was the baseline pulse amplitude (Stβ = -0.59), which in turn was influenced by age (Stβ = 0.13), central obesity (Stβ = 0.27) and inversely by HDL cholesterol (Stβ = -0.17), and systolic blood pressure (Stβ = -0.19). No association was observed with cardiovascular risk factors, previous cardiovascular event or extent of atherosclerosis (ABI and IMT, PWV). Most of the variability in baseline pulse amplitude remained unexplained (r(2) = 0.14).

CONCLUSIONS

ED, as detected by PAT in a population enriched with subjects at risk for CVD neither reflects the burden of classical risk factors (under treatment) nor the severity of atherosclerosis. Aside from central obesity and HDL cholesterol, most of the factors responsible for this ED remain unknown.

Endothelial Function in Youth: A Biomarker Modulated by Adiposity-Related Insulin Resistance

OBJECTIVE

To investigate the physical and metabolic determinants of endothelial dysfunction, an early marker of subclinical atherosclerosis, in normal weight and overweight adolescents with and without type 2 diabetes mellitus.

STUDY DESIGN

A cross-sectional study of 81 adolescents: 21 normal weight, 25 overweight with normal glucose tolerance, 19 overweight with impaired glucose regulation, and 16 with type 2 diabetes mellitus underwent evaluation of reactive hyperemia index (RHI) and augmentation index (AIx) at heart rate 75 bpm by peripheral arterial tonometry; oral glucose tolerance test, lipid profile, and hyperinsulinemic-euglycemic clamp to measure insulin sensitivity; and dual energy X-ray absorptiometry scan and abdominal magnetic resonance imaging for percentage of body fat and abdominal fat partitioning.

RESULTS

Participants across tertiles of RHI (1.2 ± 0.02, 1.5 ± 0.02, and 2.0 ± 0.05, P < .001) had similar age, sex, race, lipid profile, and blood pressure. Body mass index z-score, percentage body fat, abdominal fat, and hemoglobin A1c decreased, and insulin sensitivity increased from the first to third tertile. RHI was inversely related to percentage body fat (r = -0.29, P = .008), total (r = -0.37, P = .004), subcutaneous (r = -0.39, P = .003), and visceral (r = -0.26, P = .04) abdominal fat. AIx at heart rate 75 bpm was higher (worse) in the lower RHI tertiles (P = .04), was positively related to percentage body fat (r = 0.26, P = .021), and inversely related to age, insulin sensitivity, and inflammatory markers (tumor necrosis factor-α and plasminogen activator inhibition-1).

CONCLUSIONS

Childhood obesity, particularly abdominal adiposity, is associated with endothelial dysfunction manifested by worse reactive hyperemia and higher AIx. Insulin resistance appears to mediate this relationship.

Effects of transcutaneous electrical nerve stimulation (TENS) on arterial stiffness and blood pressure in resistant hypertensive individuals: study protocol for a randomized controlled trial

BACKGROUND

Resistant hypertension (RH) treatment requires an adequate and intense therapeutic approach. However, the results are not always satisfactory despite intensive treatment. Of the different pathophysiological mechanisms involved in the pathogenesis of RH, sympathetic overstimulation and therapies that block the sympathetic system have been widely studied. These approaches, however, are invasive and expensive. Another possible approach is by transcutaneous electrical nerve stimulation (TENS), a noninvasive method that modulates activity by using low-frequency transcutaneous electrical stimulation to inhibit primary afferent pathways. Thus, the current study will evaluate the effect of applying TENS in the cervicothoracic region of subjects with RH and will seek to develop a new low-cost and readily available therapy to treat this group of hypertensive individuals.

METHODS/DESIGN

This is a randomized, single blind (subject), parallel-assignment study controlled with a sham group and including participants aged 40 to 70 years with resistant hypertension. The trial has two arms: the treatment and control (sham group). The treatment group will be submitted to the stimulation procedure (TENS). The sham group will not be submitted to stimulation. The primary outcomes will be a reduction in the peripheral blood pressure and adverse events. The secondary outcomes will be a reduction the central blood pressure. The study will last 30 days. The sample size was calculated assuming an alpha error of 5 % to reject the null hypothesis with a statistical power of 80 %, thereby resulting in 28 participants per group (intervention versus sham).

DISCUSSION

In recent decades, RH has become very common and costly. Adequate control requires several drugs, and in many cases, treatment is not successful. Sympathetic nervous system inhibition by renal denervation and central inhibition have significant effects in reducing BP; however, these treatments are costly and invasive. Another type of sympathetic nervous system inhibition can also be noninvasively achieved by electric current. Therefore, the application of TENS may be a new therapeutic option for treating resistant hypertensive individuals.

TRIAL REGISTRATION

Clinical Trials NCT02365974.

Twelve-week randomized study to compare the effect of vildagliptin vs. glibenclamide both added-on to metformin on endothelium function in patients with type 2 diabetes and hypertension

BACKGROUND

Vildagliptin, a DPP-4 inhibitor widely used for the treatment of type 2 diabetes mellitus (T2DM), shows beneficial effects on endothelial function. This study aims to evaluate the effect of vildagliptin on endothelial function and arterial stiffness in patients with T2DM and hypertension.

METHODS

Fifty over 35-year-old patients with T2DM and hypertension, without cardiovascular disease, will be randomly allocated to two groups: group 1 will receive vildagliptin added-on to metformin and group 2, glibenclamide added-on to metformin. Biochemical tests (glycemia, glycated hemoglobin, total cholesterol, high-density lipoprotein cholesterol, triglycerides, creatinine, alanine aminotransferase, ultrasensitive C-reactive protein, and microalbuminuria), 24-h non-invasive ambulatory blood pressure monitoring, and assessment of endothelial function and arterial stiffness will be performed in both groups before and after 12 weeks of treatment. The endothelial function will be assessed by peripheral arterial tonometry, which measures the reactive hyperemia index (vasodilation), and arterial stiffness will be evaluated by applanation tonometry. All analysis will be performed using SPSS Statistical Software. For all analysis, a 2-sided P < 0.05 will be considered statistically significant.

RESULTS

The study started in December 2013 and patient recruitment is programed until October 2015. The expected results are that vildagliptin will improve the endothelial function in patients with T2DM and hypertension compared to glibenclamide treatment, independently of glycemic control.

CONCLUSIONS

It is expected that this DPP-4 inhibitor will improve endothelial function in patients with T2 DM.

TRIAL REGISTRATION

Clinical Trials NCT02145611, registered on 11 Jun 2013.

The role of metabolic syndrome in heart failure

Metabolic syndrome (MS) is a highly prevalent condition in patients affected by heart failure (HF); however, it is still unclear whether, in the setting of cardiac dysfunction, it represents an adverse risk factor for the occurrence of cardiac events. The epidemiologic implications of MS in HF have been studied intensely, as many of its components contribute to the incidence and severity of HF. In particular, insulin resistance, diabetes mellitus, and lipid abnormalities represent the main components that negatively influence disease progression and evolution. Yet, other components of the MS, i.e. overweight/obesity and high blood pressure, are favourably associated with outcome in HF patients. The aim of this review was to report epidemiology and prognostic role of MS in HF and to investigate current clinical implications and future research needs.

Peripheral arterial tonometry cannot detect patients at low risk of coronary artery disease

Background

Endothelial dysfunction precedes coronary artery disease (CAD) and can be measured by peripheral arterial tonometry (PAT). We examined the applicability of PAT to detect a low risk of CAD in a chest pain clinic.

Methods

In 93 patients, PAT was performed resulting in reactive hyperaemia (RHI) and augmentation (AIx) indices. Patients were risk classified according to HeartScore, Diamond and Forrester pretest probability (DF), exercise testing (X-ECG), and computed tomography calcium scoring (CCS) and angiography (CTA). Correlations, risk group differences and prediction of revascularisation within 1 year were calculated.

Results

RHI correlated with HeartScore (r = − 0.21, p = 0.05), AIx with DF (r = 0.26, p = 0.01). However, both were not significantly different between normal and ischaemic X-ECG groups. In addition RHI and AIx were similar between low risk as compared with intermediate-to-high risk, based on risk algorithms (RHI: 1.98 (0.67) vs 1.94 (0.78); AIx: 0.0 (21) vs 5.0 (25); p = NS), or CCS and CTA (RHI: 1.99 (0.58) vs 1.89 (0.82); AIx: − 2.0 (24) vs 4.0 (25); p = NS). Finally, RHI and AIx failed to predict revascularisation (RHI: OR 1.42, CI 0.65–3.1; AIx: OR 1.02, CI 0.98–1.05).

Conclusions

PAT cannot detect a low risk of CAD, possibly because RHI and AIx versus X-ECG, CCS and CTA represent independent processes.

Effects of a new combination of nutraceuticals with Morus alba on lipid profile, insulin sensitivity and endotelial function in dyslipidemic subjects. A cross-over, randomized, double-blind trial

Introduction

Nutraceuticals (NUT) are forms of compounds with biological activity commonly used to improve health in dosage largely exceeding those obtainable in food.

Aim

We compared, in a double blind randomized cross-over trial, the effects of two NUT combinations on the control of glico-lipidic metabolism in patients with hypercholesterolemia not on statins.

Methods

At study start patients were given dietary counseling and received placebo for 2 weeks. After this run-in period, patients were randomized: (1) Combination A [Policosanol, Red yeast rice (Monakolin K 3 mg), Berberine 500 mg, Astaxantine, Folic Acid and Coenzyme Q10] for 4 weeks followed by 4 weeks of Combination B [Red yeast rice (Monakolin K 3.3 mg), Berberine 531.25 mg and leaf extract of Morus alba]; (2) Combination B for 4 weeks followed by 4 weeks of Combination A.

Results

Combination B reduced LDL cholesterol below 130 mg/dl in 56.5 % of the patients, and Cambination A only in 21.7 % of them (p ≤ 0.027). Both treatments reduced plasma levels of triglycerides, total and LDL cholesterol and increased HDL cholesterol (all p < 0.03). Total and LDL cholesterol reduction was more pronounced in patients taking Combination B (p < 0.005). Combination B reduced also glycated hemoglobin, fasting glucose and insulin plasma levels as well as HOMA index (p < 0.005).

Conclusions

An increased content of Berberin and Monacolin K and the addition of Morus alba extract improves the effect on plasma cholesterol and on glucose metabolism of the NUT Combination. These effects may allow the speculation of a more marked improvement in cardiovascular prognosis.

Endothelial dysfunction: its clinical value and methods of assessment

Endothelial dysfunction (ED) is a systemic disorder characterized by reduced production of nitric oxide. This pathologic condition, which impairs vascular homeostasis, leads to the loss of protective properties of endothelial cells and is related to the pathogenesis of cardiovascular diseases. ED may affect every vascular bed, accounting for several clinical implications, particularly when the coronary bed is affected. Although the reliability of ED as a cardiovascular disease surrogate is still debated, many methods for its assessment have been proposed. In this review, we underline the clinical value of ED in the cardiovascular field and summarize the principal methods currently available for its assessment.

All-cause mortality and cardiovascular events with nicorandil in patients with IHD: systematic review and meta-analysis of the literature

BACKGROUND

Nicorandil is able to protect the cardiomyocytes from ischemic damage, but clear benefits of nicorandil in all-cause mortality and cardiovascular events were not consistently reported in patients with ischemic heart disease (IHD).

MATERIALS AND RESULTS

Cochrane, PubMed, EMBASE, CBM, CNKI and Wangfang databases were searched for randomized controlled trials. Data on all-cause mortality and cardiovascular events were collected. Nicorandil groups were pooled to perform a comparison with control groups and to get the pooled odds ratios (ORs) and associated 95% confidence intervals (CIs) for all-cause mortality, relative risks (RRs), and associated 95% CIs for cardiovascular events. STATA 11.0 software was used for all-cause mortality and cardiovascular events statistics. We retrieved 17 randomized controlled studies enrolling a total of 7305 patients. The addition of nicorandil treatment significantly reduced cardiovascular events (13.83% versus 18.01%; RR, 0.77; 95% CI, 0.69 to 0.86). No differences in all-cause mortality (3.83% versus 4.70%; OR, 0.81; 95% CI, 0.64 to 1.02), and repeat revascularization rate (13.06% versus 13.54%; RR, 0.95; 95% CI, 0.70 to 1.29) were observed. There was a weak linear association between cardiovascular events and nicorandil in IHD with diabetes (P=0.099).

CONCLUSIONS

The results suggest that nicorandil as an adjunct therapy to IHD is associated with reduced cardiovascular events in patients with IHD.

Characteristics of Patients With Diabetes Having Normal Coronary Arteries

We evaluated the association between risk variables in diabetic patients with normal and diseased coronary arteries in a retrospective cohort study conducted at Rashid Hospital, Dubai. A total of 4446 patients underwent coronary angiography due to various indications; 43% had type 2 diabetes mellitus (T2DM). Among the diabetic patients, 94% had diseased coronary arteries and the remaining 6% had absolutely normal arteries. The normal coronary group had significantly lower low-density lipoprotein cholesterol (LDL-C) and a higher high-density lipoprotein cholesterol (HDL-C) levels than the diseased group. Patients with normal coronaries were more likely to be females, have T2DM for a shorter duration, and were nonsmokers and non-South Asians. They also had lower levels of LDL, hemoglobin A1c, and fasting glucose and higher levels of HDL-C. Apart from these variables, genetic or environmental factors could protect these patients from atherosclerosis.

Evaluation of endothelial function by peripheral arterial tonometry and relation with the nitric oxide pathway

Endothelial dysfunction is an important component in the development of cardiovascular diseases. Endothelial function may be evaluated by peripheral arterial tonometry (PAT) which measures the vasodilator function in the microvasculature of the fingertip during reactive hyperaemia. The reactive hyperaemia index (RHI) is decreased in the presence of cardiovascular risk factors and thus far several studies have shown that PAT-RHI may provide reliable prediction of outcome. The technique is operator independent and easy to perform. Abnormalities measured by PAT follow the same trend as those measured by flow-mediated dilation in the brachial artery, but the two methods are not interchangeable. We have reviewed the recent literature in an effort to evaluate peripheral arterial tonometry as a method to assess the function of the endothelium and additionally suggest directions for future research. Special attention will be directed to the nitric oxide dependency of the reactive hyperaemia index obtained by peripheral arterial tonometry.

Physical activity in the prevention of peripheral artery disease in the elderly

Aging is a well-known cardiovascular risk factor and cardiovascular diseases (CVD) are estimated to be the most common cause of death in the elderly. Peripheral arterial disease (PAD) represents an important clinical manifestation of CVD leading to increase morbidity and mortality, especially in elderly population. The correct management of PAD population includes the prevention of cardiovascular events and relief of symptoms, most commonly intermittent claudication. Progressive physical activity is an effective treatment to improve walking distance and to reduce mortality and cardiovascular events in patients with PAD, however the ability to effectively engage in physical activity often declines with increasing age. The maintenance and increase of reserve functional capacity are important concepts in the elderly population. Ultimately, the goal in participation of physical activity in the healthy elderly population is maintenance and development of physical functional reserve capacity. Therefore, for individuals suffering of PAD, appropriate physical activity in the form of supervised exercise may serve as a primary therapy. Although there are few direct comparisons of therapeutic exercise programs vs. pharmacological or surgical interventions, these increases in walking distance are greater than those reported for the most widely used agents for claudication, pentoxyphylline, and cilostazol. Despite a reduction in mortality and improvement of quality of life caused by physical activity in the PAD population, the molecular, cellular, and functional changes that occur during physical activity are not completely understood. Therefore, this review article aims at presenting an overview of recent established clinical and molecular findings addressing the role of physical activity on PAD in the older population.

Impaired endothelial function in female adolescents with type 1 diabetes measured by peripheral artery tonometry

BACKGROUND

The reactive hyperemia peripheral artery tonometry (RH-PAT) is a newly developed method for non-invasive endothelial function assessment.

OBJECTIVE

The goal of this study is to determine whether a significant difference in RH-PAT score is present between adolescents with type 1 diabetes (T1D) in comparison with controls.

SUBJECTS AND METHODS

Thirty-four adolescents with T1D and 25 control subjects (age 12-20 years) underwent RH-PAT endothelial function testing after an overnight fast. Height, weight, body mass index (BMI), blood pressure (BP), fasting lipid profile, Tanner stage, and glucose level were determined in each child.

RESULTS

Adolescents with T1D had significantly lower RH-PAT scores compared to healthy controls, and this difference remained significant when overweight cases were not considered (p < 0.05). This difference was also observed in the female subgroup (p = 0.005). The interindividual variability in RH-PAT observations in T1D cases was not explained by BMI standard deviation score (SDS), BP SDS, age, duration of T1D, hemoglobin A1c, triglycerides, and pubertal stage, respectively.

CONCLUSIONS

The RH-PAT technique is used as a non-invasive test to assess for early vascular changes in high-risk patient groups. Endothelial dysfunction, measured by RH-PAT, was present in diabetic adolescent, especially in the female subgroup. Although additional longitudinal studies are required, early detection of this reversible process may have therapeutic and prognostic implications.

Transient ischemic dilation in SPECT myocardial perfusion imaging for prediction of severe coronary artery disease in diabetic patients

BACKGROUND

Transient ischemic dilation (TID) of the left ventricle during stress myocardial perfusion SPECT (MPS) has been shown to be a useful marker of severe coronary artery disease (CAD). However, investigations in diabetic patients with available coronary angiographic data are still limited. We evaluated the incremental diagnostic value of TID in identifying the presence of angiographically severe CAD in diabetic patients.

METHODS AND RESULTS

TID ratio values were automatically derived from rest-stress MPS in 242 diabetic patients with available coronary angiography data. A cutoff of ≥1.19 was considered to represent TID. Severe CAD (≥70% stenosis in the proximal left anterior descending artery or the left main artery, or ≥90% stenosis in two or three vessels) was identified in 69 (29%) patients. At multivariate analysis, the best independent predictors of severe CAD were summed stress score and TID (both P < .001). At incremental analysis, the addition of TID improved the power of a model including clinical data and summed stress score, increasing the global χ(2) value from 14.3 to 28.2 (P < .01). The best cutoff of summed stress score for identifying patients with severe CAD was ≥8. When the TID ratio was considered in patients with summed stress score between 3 and 7, the sensitivity for diagnosing severe CAD significantly improved from 71% to 77% (P < .05). In the overall study population, the net reclassification improvement by adding TID to a model including clinical data and summed stress score in the prediction of severe CAD was 0.40 (P < .005).

CONCLUSIONS

TID ratios obtained from rest-stress MPS provide incremental diagnostic information to standard perfusion analysis for the identification of severe and extensive CAD in diabetic patients.