Natriuretic peptides levels are related to HDL-cholesterol with no influence on endothelium dependent vasodilatation

Background: The natriuretic peptides, Brain Natriuretic Peptide (BNP), C-type Natriuretic Peptide (CNP), are mediators of cardiovascular homeostasis.The impairment of arterial ability to vasodilate, also known as endothelial dysfunction, represents the first stage of atherosclerotic damage and may be assessed as brachial flow mediated vasodilation (FMV) in human. Generally an altered brachial FMV is documented in association to several cardiovascular risk factors as hypercholesterolemia. Aim of the study was to evaluate the behaviour of BNP and CNP in hyperlipemia and the potential relationship to FMV. Patients and methods: Forty-four hyperlipemic patients (LDL-cholesterol > 130 mg/dl and/or triglycerides > 150, age 35–60 y) of both genders and 20 normolipemic patients, matched for age and sex were investigated. Results: Patients had lower values of brachial FMV in comparison to controls (3.9 ± 3.5 vs 7.5 ± 0.5%, p < 0.005), no differences were observed in BNP (4.6 ± 4.6 vs 5.9 ± 3.4 ng/mL, p = n.s) and CNP (4.1 ± 5.8 vs 5.7 ± 3.3 ng/mL, p = n.s). Univariate analysis showed a positive correlation between BNP and HDL-cholesterol values (r = 0.36, p = 0.001). In the multivariate analysis, LDL-cholesterol (β = –0.57), HDL-cholesterol (β = 0.26) and brachial artery diameter (β = –0.33) were predictors of brachial FMV. The only predictive variable for CNP was HDL-cholesterol (β = 0.37). Conclusions: The present study suggested that natriuretic peptides, BNP and CNP, are not altered in patients affected by hypercholesterolemia. Nevertheless, the levels of HDL-cholesterol are strictly related to the values of CNP. This observation, in humans, adds another mechanism to the vascular control exerted by HDL.

Prognostic impact of low-shear whole blood viscosity in hypertensive men

BACKGROUND

The role of blood viscosity as a marker for discriminating cardiovascular risk in essential hypertension remains uncertain. The aim of this study was to assess whether whole blood viscosity (WBV) could be useful in assessing cardiovascular risk in men with a first diagnosis of hypertension.

DESIGN

A total of 331 middle-aged men with newly diagnosed essential hypertension (age at entry 40-64 years, average blood pressure 151/95 mmHg) underwent low-shear-rate (0.94 s(-1)) and high-shear-rate (94.5 s(-1)) WBV determination and were then followed for a mean of 4.8 +/- 3 years (range 0-12 years).

RESULTS

Cardiovascular event rates in the bottom, middle and top tertiles of the distribution of low-shear WBV were 1.10, 2.13 and 4.43 per 100 patient-years, respectively (log-rank test, P < 0.001). After taking into account several established cardiovascular risk factors in a Cox survival analysis, a raised low-shear WBV conferred an increased risk for cardiovascular events (top vs. bottom tertile hazard ratio = 3.42, 95% confidence interval = 1.4-8.4, P = 0.006; middle vs. bottom tertile hazard ratio = 2.25, 95% confidence interval = 0.9-5.6, P = 0.09). The independent association between high-shear-rate WBV and cardiovascular events bordered statistical significance (P = 0.07). Inclusion in the survival model of low-shear-rate resulted in a significantly greater chi(2) improvement (P < 0.05) than inclusion of high-shear-rate WBV.

CONCLUSIONS

In hypertensive men, an increased WBV at low shear rate is a predictor of cardiovascular events independently from the effect of several traditional risk factors. Low-shear WBV is a better discriminator of cardiovascular risk than high-shear WBV.

Low-grade systemic inflammation impairs arterial stiffness in newly diagnosed hypercholesterolaemia

BACKGROUND

Excess of cardiovascular risk among patients with chronic inflammatory diseases has been attributed to increased arterial stiffness. Hypercholesterolaemia has been demonstrated to promote a low-grade inflammatory status. The objective of the present study was to define, in hypercholesterolaemia, the influence of plasma lipids, low-grade inflammation, and indices of adiposity on aortic pulse wave velocity, a measure of arterial stiffness and cardiovascular risk.

MATERIALS AND METHODS

Anthropometric characteristics, plasma lipids, C-reactive protein and aortic pulse wave velocity were measured in 85 subjects (60 patients with newly diagnosed never-treated hypercholesterolaemia and 25 age- and sex-matched normocholesterolaemic controls).

RESULTS

Plasma C-reactive protein and aortic pulse wave velocity were significantly higher among hypercholesterolaemic patients than in controls (P < 0.05 for both). Aortic pulse wave velocity was associated with age (r = 0.24, P = 0.04), body mass index (r = 0.33, P = 0.006), waist (r = 0.42, P < 0.001) and hip (r = 0.32, P = 0.007) circumferences, as well as with systolic (r = 0.34, P = 0.003) and diastolic (r = 0.30, P = 0.01) blood pressures, plasma C-reactive protein (r = 0.51, P < 0.001), total cholesterol (r = 0.45, P < 0.001), and low-density lipoprotein cholesterol (r = 0.46, P < 0.001). In the multivariate analysis, waist circumference and C-reactive protein levels predicted increased aortic stiffness, independently of traditional cardiovascular risk factors. The degree of independent association between cholesterol, systolic blood pressure and aortic stiffness increased when indices of adiposity and inflammation were excluded from the multivariate analysis. Comparable results were obtained when the analyses were restricted to hypercholesterolaemic patients.

CONCLUSIONS

Low-grade systemic inflammation and abdominal fat, more than traditional risk factors, are major determinants of reduced arterial distensibility in hypercholesterolaemia.

Effects of fenofibrate on endothelial function and cell adhesion molecules during post-prandial lipemia in hypertriglyceridemia

BACKGROUND

Fasting and post-prandial hypertriglyceridemia have been associated with endothelial dysfunction.

OBJECTIVE

To investigate the effects of a 3-month treatment with fenofibrate (200 mg daily) on endothelial reactivity and inflammatory state in hypertriglyceridemic patients at fast and after an oral fat load.

METHODS

Brachial flow-mediated vasodilation (FMV) and the circulating levels of intercellular adhesion molecule (ICAM) and vascular cellular adhesion molecule (VCAM) were determined in 10 hypertriglyceridemic patients.

RESULTS

Before treatment, post-prandial phase was characterized by an increase in triglycerides (3.7 +/- 1 mmol/L at baseline vs. 4.2 +/- 1, 6.5 +/- 1, 6.6 +/- 2, and 5.3 +/- 2 mmol/L after 2, 4, 6, and 8 h), a decrease in FMV (4.3 +/- 2% at baseline vs. 2.8 +/- 1, 2.2 +/- 1, and 1.3 +/- 1% after 2, 4, and 6 h), and an increase in ICAM and VCAM. After fenofibrate there was a significant reduction in fasting triglycerides (3.7 +/- 1.3 vs. 2.1 +/- 0.8 mmol/L), ICAM (480 +/- 113 vs. 269 +/- 65 ng/mL) and VCAM (1821 +/- 570 vs. 1104 +/- 376 ng/mL), and an increase in FMV (4.3 +/- 2 vs. 7.1 +/- 2%). Post-prandially triglycerides increased (2.1 +/- 1 at baseline vs. 2.4 +/- 2 and 3.6 +/- 1 mmol/L after 4 and 6 h), FMV decreased (7.1 +/- 2 at baseline vs. 5.8 +/- 2, 5.5 +/- 2, 5.9 +/- 2, 6.4 +/- 2% after 2, 4, 6, and 8 h), and there was an increase of ICAM and VCAM. Before therapy post-prandial changes in FMV had an inverse correlation with the changes in triglycerides (r = -0.34; P < 0.05) and ICAM (r = -0.66; P < 0.001).

CONCLUSIONS

The transient endothelial dysfunction observed in hypertriglyceridemic subjects during post-prandial lipemia is mediated by post-prandial triglyceride increase and by the activation of inflammatory response. The anti-inflammatory activity of fenofibrate may represent an additional mechanism of its favorable action on the endothelial function during fasting and the post-prandial phase.

Endothelial dysfunction in young patients with rheumatoid arthritis and low disease activity

BACKGROUND

Rheumatoid arthritis (RA) is associated with an increased risk of cardiovascular disease. Endothelial dysfunction represents the earliest stage of atherosclerosis.

OBJECTIVE

To evaluate the influence of chronic inflammatory state on endothelial function in patients with RA by measuring endothelial reactivity in young patients with RA with low disease activity and without traditional cardiovascular risk factors.

METHODS

Brachial flow mediated vasodilatation (FMV), assessed by non-invasive ultrasound, was evaluated in 32 young to middle aged patients with RA (age </=59 years), with DAS28 </=3.2 and without overt cardiovascular disease, and in 28 age and sex matched controls.

RESULTS

Mean (SD) FMV was significantly lower in patients than in controls (3.2 (1.3)% v 5.7 (2.0)%; p<0.001), inversely related to low density lipoprotein cholesterol (r = -0.45, p<0.05) and C reactive protein (CRP), expressed as the value at the moment of ultrasound evaluation (r = -0.44, p<0.05), as the average of CRP levels evaluated at different times during the disease (r = -0.47, p<0.05), or as the average of >/=4 determinations multiplied by the disease duration (r = -0.40, p<0.05). In a multivariate regression model, a lower brachial flow mediated vasodilatation was independently predicted by low density lipoprotein cholesterol (beta = -0.40, p<0.05), average CRP levels multiplied by the disease duration (beta = -0.44, p<0.05), and brachial artery diameter (beta = -0.28, p<0.05).

CONCLUSIONS

Young to middle aged patients with RA with low disease activity, free from cardiovascular risk factors and overt cardiovascular disease, have an altered endothelial reactivity that seems to be primarily related to the disease associated chronic inflammatory condition.

Endotheliale Dysfunktion und kardiovaskuläre Ereignisse bei Patienten mit peripherer arterieller Verschlusskrankheit

Background: Patients with peripheral arterial disease (PAD) are characterized by a high mortality for cardiovascular events. An impairment of endothelial function, expressed as brachial-artery flow-mediated vasodilation (FMV), has been described in PAD patients. Aim of this study was to investigate the association between FMV and cardiovascular events in patients with PAD. Patients and methods: Thirty-eight patients with intermittent claudication (71% men, mean age 71 years) were divided into two groups according to the presence or absence of previous major cardiovascular events (myocardial infarction or stroke). Results: Brachial FMV was significantly lower in patients with a history of myocardial infarction or stroke (n = 16) than in patients without cardiovascular events (3.2 ± 3.6% vs. 5.7 ± 3.6%; p = 0.042). In the group with cardiovascular events there was a significantly higher proportion of subjects in the lower FMV tertile (56% vs. 18%), and a lower proportion of subjects in the upper tertile (25% vs. 41%; chi2 test, p = 0.047). Conclusion: We conclude that FMV of the brachial artery is significantly reduced in PAD patients with a history of stroke and myocardial infarction. These cross-sectional results suggest a potential role of FMV as a marker of major cardiovascular events.

Blood rheology in men with essential hypertension and capillary rarefaction

The pathophysiological significance of hyperviscosity and capillary rarefaction in untreated essential hypertension is unknown. Fifty untreated hypertensive men with capillary rarefaction (intravital capillaroscopy) and 20 age- and sex-matched normotensive controls underwent full haemorheological profiling (blood viscosity at high and low shear, haematocrit, platelet and leukocyte counts, fibrinogen and total protein concentrations, P-selectin levels, erythrocyte and leukocyte filterability rates and erythrocyte deformability and aggregation indexes). Subjects with skin capillary density below the group median had younger age, higher diastolic pressure, higher blood viscosity at low shear, higher P-selectin levels, higher erythrocyte and leukocyte filterability rates, and higher erythrocyte aggregation indexes (all P < 0.01). In contrast, patients with greater skin capillary density had a greater plasma viscosity (P < 0.05). The conclusions were that in untreated hypertensive men, capillary rarefaction and hyperviscosity are associated to an increased diastolic blood pressure and to an adverse haemorheological profile.

Prevalent influence of systolic over pulse pressure on left ventricular mass in essential hypertension

BACKGROUND

Elevated pulse pressure, an index of increased large artery stiffness, has been associated with increased left ventricular mass. It is unknown whether this relation is independent or mediated by other blood pressure components.

METHODS AND RESULTS

We examined data in 2545 untreated hypertensive subjects (45% women) who underwent echocardiography and 24-h ambulatory blood pressure monitoring. Left ventricular mass increased with all blood pressure components and all associations were closer with ambulatory than with office blood pressure. In a multiple regression analysis, after adjustment for the significant association with age, gender, body weight and duration of hypertension, the proportion of variability of left ventricular mass explained by systolic blood pressure was greater than that explained by other blood pressure components. When different blood pressure components were forced into the same model, the same degree of left ventricular mass variability was accounted for by models including 24-h systolic blood pressure alone, or 24-h mean blood pressure plus 24-h pulse pressure, or 24-h diastolic blood pressure plus 24-h pulse pressure. When 24-h systolic blood pressure and 24-h pulse pressure were forced into the same model, 24-h pulse pressure lost statistical significance.

CONCLUSIONS

The association between pulse pressure and left ventricular mass is explained by systolic blood pressure, which is the main pressure determinant of left ventricular mass in essential hypertension.

Left ventricular mass and systolic dysfunction in essential hypertension

A relation between left ventricular (LV) hypertrophy and depressed midwall systolic function has been described in hypertensive subjects. However, a strong confounding factor in this relation is concentric geometry, which is both a powerful determinant of depressed midwall systolic function and a correlate of LV mass in hypertension. To evaluate the independent contribution of LV mass to depressed systolic function, 1827 patients with never-treated essential hypertension (age 48 +/- 12 years, men 58%) underwent M-mode echocardiography under two-dimensional guidance. Relative wall thickness was the strongest determinant of low midwall fractional shortening (r = -0.63, P < 0.0001). The significant inverse relation observed between LV mass and midwall fractional shortening (r = -0.43, P < 0.0001) persisted after taking into account the effect of relative wall thickness (partial r = -0.27, P < 0.0001). Within each sex-specific quintile of relative wall thickness, prevalence of subnormal afterload-corrected midwall systolic function was greater in subjects with, than in subjects without, LV hypertrophy (P < 0.05 for the first, third, fourth and fifth quintile). In a multiple linear regression analysis, both LV mass (P < 0.0001) and relative wall thickness (P < 0.0001) were independent predictors of a reduced midwall fractional shortening. In conclusion, the inverse association between LV mass and midwall systolic function is partly independent from the effect of relative wall thickness. LV hypertrophy is a determinant of subclinical LV dysfunction independently of the concomitant changes in chamber geometry.

High-density lipoprotein cholesterol and left ventricular hypertrophy in essential hypertension

OBJECTIVE

The proportion of left ventricular (LV) mass variability explained by blood pressure in essential hypertension is small, and several non-haemodynamic determinants of LV mass have been identified or hypothesized. This study examines the possible relation between blood lipids and LV mass in hypertension.

DESIGN

Never-treated non-diabetic hypertensive patients.

SETTING

Hospital hypertension outpatient clinics in Umbria, Italy.

PATIENTS

We investigated the association between high-density lipoprotein (HDL)-cholesterol and echocardiographic LV mass in 1306 never-treated subjects with essential hypertension. Subjects with previous cardiovascular events, diabetes and current or previous antihypertensive or lipid-lowering therapy were excluded.

RESULTS

HDL-cholesterol showed an inverse association with LV mass (r = -0.30, P < 0.001). No association was found between LV mass and total or low-density lipoprotein cholesterol. With multiple linear regression analysis we tested the independent contribution of several potential determinants of LV mass in women and in men. Average 24 h blood pressure (both pulse and mean), body mass index, height, stroke volume, age (all P < 0.01) and low HDL-cholesterol (P < 0.0001 in women, P < 0.001 in men) were associated with a greater LV mass in both sexes. Triglycerides showed a weak univariate association with LV mass in women (r = 0.11, P < 0.02), which did not hold in a multivariate analysis.

CONCLUSIONS

Low HDL-cholesterol is an independent predictor of LV mass in untreated hypertensive subjects. Common hormonal and metabolic mechanisms, including insulin resistance, could explain this association, which may contribute to the adverse prognostic significance of low HDL-cholesterol levels.

Optimizing assessment of carotid and femoral intima-media thickness in essential hypertension

Large artery intima-media thickness (IMT) is considered an integrated marker for the total individual burden of arteriosclerosis, and a graded index for cardiovascular risk. However, several different aggregate indexes of IMT on B-mode ultrasound have been used by various investigators, and the optimal number of IMT readings is currently unsettled. In 128 newly diagnosed, never treated, uncomplicated hypertensive subjects aged <55 years (43 +/- 9 years, blood pressure [BP] 152/99 mm Hg), we measured left ventricular mass (M-mode echocardiography, average of five or more measurements) and IMT of common carotid and common femoral arteries. For each segment, 12 IMT measurements were performed, and the average of 1 and 3 readings (right far wall), 6 readings (right side), and 12 readings (right and left side, far and near wall, 3 sampling points) was analyzed. The relation of IMT with left ventricular mass increased progressively with increasing number of readings, from 0.35 (1 reading) to 0.51 (12 readings) for common carotid artery, and from 0.31 to 0.56 for common femoral artery (both P <.001). For each 0.2-mm increase in common femoral IMT, the age-adjusted relative risk of having left ventricular hypertrophy was 1.31 for 1 reading, and increased up to 3.59 for the average of 12 readings. In summary, the association of IMT with left ventricular mass depends strongly on the number of IMT readings. The average of several readings in each segment, including right and left side and far and near wall, carries the closest association to left ventricular mass, and should be preferred for clinical purposes in hypertensive subjects.