Non-invasive measurements of arterial structure and function: repeatability, interrelationships and trial sample size

1998 ◽  
Vol 95 (6) ◽  
pp. 669-679 ◽  
Author(s):  
Yu-Lu LIANG ◽  
Helena TEEDE ◽  
Dimitra KOTSOPOULOS ◽  
Louise SHIEL ◽  
James D. CAMERON ◽  
...  
Keyword(s):  
Sample Size ◽  
Augmentation Index ◽  
Arterial Compliance ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Flow Mediated Dilation ◽  
Experimental Conditions ◽  
Risk Factor Modification ◽  
Media Thickness ◽  
Systemic Artery

1. Repeatability of measurements of arterial compliance and flow-mediated dilation of the brachial artery has been infrequently reported, despite increasing use in interventional and risk-factor modification studies. Furthermore, little is known about the interrelationships of the various indices. The purposes of this study were to determine the repeatability and interrelationships of a range of arterial indices. 2. Fifty healthy volunteers, 20 men and 30 women, aged 20–70 (mean 46.5) years, were studied on two occasions, using an identical protocol, at a mean interval of 2.5 weeks. Tonometry, ultrasound and Doppler technique were used to measure the following: carotid wall intima-media thickness (IMT), total systemic artery compliance (SAC), arterial pulse wave velocity [PWV aorto-femoral (A-F), and femoral-dorsalis pedis (F-D)], carotid distensibility coefficient (DC) and carotid augmentation index (AI). Brachial flow-mediated dilation was measured in 30 subjects with analysis of diameter change for 4 min post ischaemia. 3. There were no systematic differences over the observed range of measurements for any of the reported parameters. Coefficients of variation were as follows: IMT 2.8%, SAC 9.2%, PWV(A-F) 3.2%, PWV(F-D) 5.0%, DC 10.0%, AI 1.3%. Brachial flow-mediated dilation curves were not different between visits; changes were maximum 60-s post ischaemia. All indices of arterial compliance were significantly correlated with age. The three different indices of central arterial compliance [SAC, PWV(A-F) and AI] were significantly correlated with carotid intima-media thickness. 4. Under controlled experimental conditions there was good repeatability of measurements of indices between sessions of both intrinsic and functional arterial mechanical properties (central and carotid arterial compliance, intima-media thickness and brachial flow-mediated dilation). Sample size tables for clinical trials using these indices are presented.

scholarly journals FLOW MEDIATED DILATION AND CAROTID INTIMA MEDIA THICKNESS IN PATIENTS WITH CHRONIC GASTRITIS ASSOCIATED WITH HELICOBACTER PYLORI INFECTION

2017 ◽  
Vol 54 (4) ◽  
pp. 300-304 ◽  
Author(s):  
Arezo JUDAKI ◽  
Siros NOROZI ◽  
Mohammad Reza Hafezi AHMADI ◽  
Samira Mis GHAVAM ◽  
Khairollah ASADOLLAHI ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Endothelial Dysfunction ◽  
Chronic Gastritis ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Control Group ◽  
Flow Mediated Dilation ◽  
Infection Group ◽  
Media Thickness ◽  
H Pylori

ABSTRACT BACKGROUND: Endothelial dysfunction is one of the early stages of vascular diseases. OBJECTIVE: The aim of this study was to investigate the endothelial dysfunction markers in patients with chronic gastritis associated with Helicobacter pylori (H. pylori) infection. METHODS: By a cross sectional study, basic and clinical information of 120 participants (40 patients with positive H. pylori infection, 40 patients with negative H. pylori infection and 40 healthy people) were analyzed. Carotid intima media thickness and flow-mediated dilation levels were measured in all patients and controls. Soluble vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were measured with Elisa for all subjects. IgG level was assessed in chronic gastritis patients. RESULTS: The flow-mediated dilation level in patients with positive H. pylori infection (0.17%±0.09) was significantly lower than those with negative H. pylori infection (0.21% ±0.10, P<0.05) and compared to the control group (0.27% ±0.11, P<0.05). Carotid intima media thickness level in patients with positive H. pylori infection (0.58±0.13 mm) was significantly higher than those with negative H. pylori infection (0.48±0.32 mm, P<0.05) and compared to the control group (0.36±0.44mm, P<0.05). The mean level of sICAM-1 in positive H. pylori infection group (352.16±7.54 pg/mL) was higher than negative H. pylori infection group (332.64±8.75 pg/mL =0.75) and compared to the control group (236.32±12.43 pg/mL, P<0.05). A direct relationship was revealed between flow-mediated dilation and carotid intima media thickness changes and between sICAM-1 and sVCAM-1 associated with the level of H. pylori IgG in chronic gastritis. CONCLUSION: The levels of flow-mediated dilation, carotid intima media thickness and sICAM-1 were higher among patients with positive H. pylori infection. Patients with chronic gastritis associated with H. pylori infection are at risk of endothelial dysfunction due to flow-mediated dilation and carotid intima media thickness abnormalities and increased level of sICAM-1 and sVCAM-1.

scholarly journals Relationship of arterial wall parameters to cardiovascular risk factors and cardiovascular risk assessed by SCORE system

Medicina ◽  
2007 ◽  
Vol 43 (7) ◽  
pp. 529 ◽  
Author(s):  
Milda Kovaitė ◽  
Žaneta Petrulionienė ◽  
Ligita Ryliškytė ◽  
Jolita Badarienė ◽  
Alma Čypienė ◽  
...  
Keyword(s):  
Cardiovascular Risk ◽  
Pulse Wave Velocity ◽  
Wave Velocity ◽  
Arterial Wall ◽  
Pulse Wave ◽  
Augmentation Index ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Media Thickness ◽  
Flow Mediated Dilatation

Objective. To investigate the relationship of arterial wall parameters (flow-mediated dilatation of the brachial artery, augmentation index, pulse wave velocity, stiffness index, carotid intima-media thickness) to conventional cardiovascular risk factors and cardiovascular risk assessed by SCORE system. Material and methods. A total of 209 subjects aged 40–65 years without clinically overt cardiovascular disease were examined. Parameters of arterial stiffness were obtained by two methods: augmentation index and carotid-radial pulse wave velocity by applanation tonometry and stiffness index by the means of finger photoplethysmography. Flow-mediated dilatation of the brachial artery, reflecting endothelial function, and carotid intima-media thickness was determined using a high-resolution B-mode ultrasonography. Results. Age and the presence of diabetes strongly influenced all parameters of the arterial wall (diabetes was not independent predictor when evaluating augmentation index). Mean arterial pressure and gender were independent predictors for arterial stiffness parameters – carotid-radial pulse wave velocity and augmentation index. Flow-mediated dilatation was strongly dependent on the diameter of the brachial artery, age, and body mass index. Using logistic regression, it was found that pulse wave velocity (P=0.014), intima-media thickness (P=0.004), and flow-mediated dilatation (P=0.020) were important parameters dividing subjects to the groups of increased (³5%) and low (<5%) cardiovascular risk assessed by SCORE system. The cutoff values for intima-media thickness and pulse wave velocity were 0.078 cm and 8.95 m/s, respectively. Conclusions. Arterial wall parameters are closely associated with conventional risk factors; they are influenced by age and the presence of diabetes. Arterial stiffness parameters are also influenced by mean arterial pressure; high-density lipoprotein cholesterol has influence on carotid intima-media thickness. Cutoff values for carotid intima-media thickness and carotid-radial pulse wave velocity could help to discriminate patients with increased cardiovascular risk.

Abstract 2648: Design of Carotid Intima-Media Thickness Trials

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Gregory W Evans ◽  
Mike K Palmer ◽  
Daniel H O’Leary ◽  
John R Crouse ◽  
Michiel L Bots ◽  
...  
Keyword(s):  
Sample Size ◽  
Treatment Effect ◽  
Subclinical Atherosclerosis ◽  
Intima Media Thickness ◽  
Carotid Intima Media Thickness ◽  
Double Blind ◽  
Aged Patients ◽  
Media Thickness ◽  
The Impact

Carotid artery intima-media thickness (CIMT) assessed by B-mode ultrasound is an accepted marker for subclinical atherosclerosis commonly used in clinical trials. Their sample size and power calculations apply 2-sample independent t-tests and within group variance in progression rates from the literature. However, this approach obscures the impact of differences in study designs including length of follow-up and differences in the number of and interval between ultrasound scans. These effects can be assessed using common sample size formula for longitudinal models, but this approach requires decomposition of the total variance into between and within subject components that have not generally been reported in the literature. Here, we derive these variance components for the Measuring Effects on intima-media Thickness: an Evaluation of Rosuvastatin (METEOR) study, a randomized, double-blind trial that demonstrated treatment with 40 mg rosuvastatin significantly slowed CIMT progression in middle-aged patients with a low Framingham risk of coronary heart disease and subclinical atherosclerosis (baseline maximum CIMT ≥1.2-<3.5mm). We examined the impact of differing follow-up periods, use of intermediate scans, and use of duplicate scans using both sample size calculations and actual analyses based on subsets of the METEOR data. Reductions in study length or number of scans result in increased variances and larger sample sizes to detect a given treatment effect. Table shows the impact of duplicate scans at baseline and end of the 2-year study, with and without intermediate scans performed every 6 months, on the sample size required to detect a treatment effect of 0.012 mm/year. These results underscore the importance of considering the number and spacing of ultrasound exams explicitly during study design, and suggest that reductions in scanning frequency may seriously erode study power and/or increase costs by requiring recruitment of additional subjects.

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