Correction of carotid intima-media thickness for adaptive dependence on tensile stress: implication for cardiovascular risk assessment.

Purpose: Early artery wall-thickening detected by ultrasound-assessed increased carotid intima-media thickness (IMT) may reflect atherosclerosis or represent an adaptive response to keep homeostasis tensile stress that is related inversely to wall thickness by Laplace's equation. We attempted to discriminate between both mechanisms by correcting IMT for its inverse association with tensile stress.

Methods: Common carotid IMT and lumen diameter (D) where determined in 40 healthy controls and 119 never-treated asymptomatic patients with >or=1 traditional cardiovascular risk factor.

New assessment of endothelium-dependent flow-mediated vasodilation to characterize endothelium dysfunction.

The vascular endothelium plays an important role in the regulation of vascular tone, cell growth, inflammation, and thrombogenicity. Endothelium dysfunction, then, is considered to promote several disorders that initiate the atherosclerosis process. Vascular tone dysfunction can be determined by high-resolution ultrasonographic imaging of the brachial artery, enabling one to assess endothelium-dependent flow-mediated dilation (FMD).

Impact of shear stimulus, risk factor burden and early atherosclerosis on the time-course of brachial artery flow-mediated vasodilation.

Objectives: Our aim was to analyze flow-mediated dilation (FMD) time-course in response to forearm occlusion in the clinical setting.

Methods And Results: In 50 asymptomatic subjects, monitoring software measuring continuous beat-to-beat change in brachial artery diameter was used to determine FMD magnitude in percentage change in peak diameter from baseline (FMD-DeltaD), time to peak diameter after occlusion release (FMD-t(peak)), integrated FMD response calculated as area under dilation curve (FMD-AUC), maximum FMD rate calculated as maximal slope of dilation (FMD-MDR). FMD-DeltaD and FMD-MDR correlated positively with peak wall shear stress (P < 0.

Comparative performance of subclinical atherosclerosis tests in predicting coronary heart disease in asymptomatic individuals.

The prognostic performance of subclinical atherosclerosis in predicting coronary heart disease (CHD) needs to be clarified because of the existence of many non-invasive tests available for its detection in the clinical setting: ultrasound measurement of carotid intima-media thickness (IMT) and plaque, cardiac computed tomography assessment of coronary artery calcium, Doppler stethoscope measurement of ankle-arm index pressure (AAI), and mechanographic or Doppler determination of aortic pulse wave velocity (PWV). Data analysis of the main prospective studies in asymptomatic populations allows the establishment of a dose-response relationship between subclinical atherosclerosis burden and cumulative incidence of future CHD event (absolute risk). Negative subclinical atherosclerosis testing conveys a low 10-year CHD risk inferior to 10% whatever the test considered, i.

New monitoring software for larger clinical application of brachial artery flow-mediated vasodilatation measurements.

Background: The reproducibility of brachial artery flow-mediated vasodilatation (FMD) is limited by the operator dependence of most measurement methods.

Methods: A new automated computerized analysis of brachial artery ultrasound scan providing a continuous evolution of the diameter during acute hyperemia, reactive to short hyperemia of the forearm and hand, was tested in 10 normal volunteers and 26 asymptomatic patients with cardiovascular risk factors such as hypertension, hypercholesterolemia, heavy smoking, history of premature coronary heart disease and the metabolic syndrome. FMD was the percentage of the maximum hyperemic diastolic diameter from baseline.

Relationship of circulating biomarkers of inflammation and hemostasis with preclinical atherosclerotic burden in nonsmoking hypercholesterolemic men.

Background: Relations of mediators of inflammation and hemostasis with preclinical atherosclerosis have been poorly analyzed. The aim of this study was to test potential associations of these blood markers with indicators of cardiovascular risk and atherosclerotic burden in asymptomatic, nonsmoking, hypercholesterolemic men.

Methods: A total of 87 men underwent cardiovascular risk assessment by means of 10-year Framingham risk calculation (median 9%) and atherosclerotic burden evaluation by means of ultrasonographic measurement of common carotid intima-media thickness and assessment of atherosclerotic plaques at three arterial sites (three-site plaques).

Effects of enhanced external counterpulsation on carotid circulation in patients with coronary artery disease.

Background: Enhanced external counterpulsation (EECP) is a noninvasive method previously shown to improve measures of myocardial ischemia in patients with coronary artery disease. However, the concomitant effects of EECP on large and small arterial properties have been poorly examined. In a randomized controlled study, we investigated whether arterial stiffness and resistance of the carotid circulation are altered by EECP.

Performance of subclinical arterial disease detection as a screening test for coronary heart disease.

Traditional risk factors are poor screening tests for coronary heart disease, whereas clinical arterial disease represents its strongest predictor. This raises the question whether subclinical arterial disease may also predict coronary disease. Using published data of prospective studies of subclinical arterial disease, we calculated the incidence of coronary event associated with the absence or presence of atherosclerosis as defined by dichotomous characterization of the following markers: low or high intima-media thickness or the absence or presence of plaque, assessed by carotid ultrasound; zero or high total coronary artery calcium score assessed by computed tomography; normal or decreased ankle-arm index pressure assessed by Doppler stethoscope; and low or high aortic pulse wave velocity assessed by mecanography.

Cyclic GMP release by acute enhanced external counterpulsation.

Background: Enhanced external counterpulsation (EECP) is a noninvasive, pneumatic technique that provides favorable effects in patients with coronary artery disease and heart failure. The mechanisms by which EECP exerts its beneficial effects remain poorly understood. Cyclic GMP (cGMP) regulates vascular smooth muscle tone that may improve arterial function.

Decreased number of circulating CD34+KDR+ cells in asymptomatic subjects with preclinical atherosclerosis.

Objectives: To assess whether circulating endothelial progenitor cells (CEPCs) can be considered as a cardiovascular risk marker before event has occurred, that is less firmly established than in clinically overt atherosclerosis.

Methods: Number of CD34+KDR+ cell number per ml blood was measured by flow cytometry in 84 untreated subjects without cardiovascular disease. Atherosclerotic plaque was detected by ultrasound in carotid, abdominal aortic and femoral sites and the number of sites affected by plaque among these three sites was counted as 0, 1, 2 or 3.

Current possibilities for detecting high risk of cardiovascular disease.

Current possibilities for better detecting high risk of coronary heart disease (CHD) and stroke and peripheral arterial disease are described in this review. A first step is based on risk factors assessment that allows establishing high-risk diagnostic, either by detecting a condition termed as "CHD risk equivalent" and defined by one or more severe major risk factor, or by calculating multifactorial risk in asymptomatic subjects with a global risk score integrating several moderate risk factors. A second diagnostic step, concerning subjects not considered at high-risk by risk factors assessment, is based on non-invasive detection of sub clinical atherosclerosis via a wide variety of structural and functional arterial markers.

Differential associations of statin and fibrate treatment with carotid arterial remodeling.

Background: The effects of statins on intima-media thickness (IMT) are well documented, whereas those of fibrates are unknown. Therefore we compared IMT under treatment with each class of drugs.

Methods: We studied a cohort of consecutive dyslipidemic subjects treated with statin (n = 291) or fibrate (n = 82) drugs.

May subclinical arterial disease help to better detect and treat high-risk asymptomatic individuals?

The diagnosis of high risk of cardiovascular disease (CVD) in subjects without clinically overt CVD has been somewhat improved by integrating multiple traditional risk factors via appropriate risk score programs. Nevertheless, novel measures of CVD risk are being proposed and debated to further improve high-risk detection by their addition to, or their use in place of, traditional risk factors. Among such measures, non-invasive detection of subclinical arterial disease is a subject of growing interest.

Sialic acid as a protective barrier against neointima development.

Arterial sialic acid (SA) has been shown to attenuate the binding of fibrinogen and low-density lipoproteins (LDL) to the vessel wall, presumably protecting against atherosclerosis. This study was aimed to assess the effect of changes in SA content in intimal thickening, an early step in the development of atherosclerosis. New Zealand white rabbits were subjected to bilateral carotid periarterial collaring, followed by in situ-perfusion with neuroaminidase (random artery) and with vehicle (contralateral control artery).

Differences between markers of atherogenic lipoproteins in predicting high cardiovascular risk and subclinical atherosclerosis in asymptomatic men.

Objective: As main markers of atherogenic lipoproteins, apolipoprotein B (apoB), non-HDL cholesterol (non-HDLC), and LDL cholesterol (LDLC) do not seem equipotent to predict cardiovascular complications, we have compared simultaneously their capacity to predict high cardiovascular risk and subclinical atherosclerosis in a primary prevention population.

Methods: In 723 asymptomatic men, we measured apoB, non-HDLC, and LDLC, and we determined concomitantly coronary heart disease (CHD) risk equivalent defined by National Cholesterol Education Program guidelines, ultrasound-assessed extra-coronary plaques at multiple sites, and electron beam computed tomography-assessed high coronary calcium.

Results: Odds ratios (95% confidence interval) per standard deviation of apoB, non-HDLC, and LDLC of having: (i) CHD risk equivalent were 1.

Plasma cGMP and large artery remodeling in asymptomatic men.

cGMP regulates vascular smooth muscle tone and arterial wall response to proliferative signals. We determined plasma cGMP and carotid artery intima-media thickness (IMT) and diameter in 84 asymptomatic men submitted to investigation of their cardiovascular risk profiles. Plasma cGMP was positively associated with IMT (P<0.

Large artery wall thickening and its determinants under antihypertensive treatment: the IMT-INSIGHT study.

Background: Calcium antagonists retard progression of intima-media thickness (IMT), but whether this retardation covers heterogeneous individual patient responses of IMT change is unknown.

Methods: Hypertensive patients treated for 4 years with nifedipine (n = 115) or coamilozide (n = 127) underwent ultrasound measurements of carotid IMT at baseline, 4 months later, and then every year.

Results: A histogram of individual slopes of IMT change (least square regression of IMT to time) during treatment identified three categories of slopes according to the 20th and 80th percentiles of distribution: lower, intermediate and higher percentiles of IMT slope; the proportion of categories of IMT slope differed between treatments (P < 0.

[The vascular smooth muscle of great arteries: local control site of arterial buffering function?].

Introduction And Objectives: To characterize the viscoelastic properties of the aorta and pulmonary arteries and the effects of vascular smooth muscle activation on arterial buffering function.

Material And Method: Aortic and pulmonary artery pressure and diameter were measured in six anesthetized sheep under baseline conditions, and during arterial hypertension induced by mechanical vascular occlusion (passive), and i.v.

Comparison of new ultrasound index with laser reference and viscosity indexes for erythrocyte aggregation quantification.

We have previously established new ultrasonic indexes for erythrocyte aggregation using a Couette device, and validated them toward the Rayleigh's theory and reproducibility. Two hydrodynamic protocols were applied on various suspensions and their aggregation degrees were characterized by: 1. for the decreasing shear rates protocol: the power P(US) at the nominal frequency of the transducer used; 2.

Influence of hypertension on early carotid artery remodeling.

Objective: We aimed to analyze the influence of hypertension on early large artery remodeling.

Methods And Results: Carotid intima-media thickness (IMT) and diameter were measured ultrasonographically in 394 normotensive subjects and 327 untreated and 528 treated hypertensive patients. IMT and diameter were increased in hypertensive groups, treated or untreated, compared with the normotensive group (P<0.

Brief report: carotid intima-media thickness in heavily pretreated HIV-infected patients.

The authors used ultrasonography to measure carotid artery intima-media thickness (IMT) in 36 HIV-infected patients taking highly active antiretroviral therapy (cases) and in two control groups without (control group 1) or with (control group 2) blood lipid and glucose disturbances similar to those of the patients. Case IMT values were 8% higher than control group 1 IMT values (p <.05) but not different from control group 2 IMT values.

Clinical use of nifedipine GITS in the treatment of hypertension: an overview.

Given the major role of elevated blood pressure in the pathogenesis of both stroke and coronary heart disease, one of the biggest challenges facing public health authorities and medical practitioners is the control of hypertension worldwide, both in individual patients and at the population level. The prevalence of hypertension increases with age and is nearly 60% in people aged 65 - 74 years. With increasing age, polymorbidity and polypharmacy usually contribute to an increasingly complex approach to manage the respective clinical conditions, including the treatment of hypertension.

Determinants of progression of coronary artery calcifications in asymptomatic men at high cardiovascular risk.

Extended coronary artery calcifications (CAC) are predictive for cardiovascular complications but little is known about factors likely to influence CAC deposit. An analysis was undertaken to assess the cardiovascular risk factors that are capable of predicting CAC change over time. A retrospective analysis of CAC change was carried out in 55 asymptomatic men who underwent sequential electron beam computed tomographic measurement of CAC score a mean of 3.

Effects of calcium channel blockers on atherosclerosis: new insights.

Atherosclerotic disease is the most frequent cause of death in the western world. The key role of calcium ions in atherogenesis has created interest in the antiatherogenic potential of calcium channel blockers. Nifedipine, administered in a long-acting gastrointestinal transport system (GITS) formulation, was shown to have similar efficacy to the diuretic co-amilozide in the International Nifedipine GITS Study: Intervention as a Goal in Hypertension Treatment (INSIGHT).

A new ultrasound principle for characterizing erythrocyte aggregation: in vitro reproducibility and validation.

Rationale And Objectives: There is no method currently available to quantify erythrocyte aggregation in vivo. In this work, using a Couette system, we defined new ultrasound indexes potentially applicable for non-invasive investigations.

Methods: Two ultrasound protocols were developed: (1) a protocol in which decreasing shear rates ranging from 200 to 1 s-1 were applied to solutions; and (2) a protocol in which a 200 s-1 shear rate was initially applied followed by stoppage of flow (a kinetics protocol).