Intima-Media Thickness Does Not Differ between Two Common Carotid Artery Segments in Children

Carotid intima-media thickness (cIMT) is a surrogate marker of early atherosclerotic changes in children. cIMT-studies are hard to compare, due to variations in ultrasound protocols, especially regarding the common carotid artery (CCA) segment measured in relation to the bulb. This study's purpose was therefore to compare two distinct CCA segments in children, to see if cIMT values differ substantially according to the site of measurement. cIMT was assessed after power calculation in 30 children (15 girls) aged 8-17, using B-Mode ultrasound (5-13 MHz) at two CCA locations. The first measurement was performed over a distance of 1 cm immediately after the bulb (A), the second 1 cm proximal the bulb (B) over the same distance of 1cm length. Means of end-diastolic far wall cIMT were compared between measurement A and B. cIMT in 30 participants was 0.51 +/- 0.06 mm for measurement A and 0.51 +/- 0.05 mm for measurement B. Results did not differ significantly (p = .947) over a distance of 2 cm after the bulb. According to our results, studies measuring CCA IMT within the first 2 cm, either close to the bulb or further proximal, can be compared. This will improve interpretation of data and application of reference values

Comparison of Two Measurement Devices for Pulse Wave Velocity in Children: Which Tool Is Useful to Detect Vascular Alterations Caused by Overweight?

Vascular alterations may lead to manifest cardiovascular disease in future life. There is a tremendous time delay between the onset and obvious clinical appearance of vascular alterations. Pulse wave velocity (PWV) is one subclinical parameter to detect vascular alterations at a very early stage. Different techniques exist tomeasure PWV non-invasively as a vascular parameter-all with their own technique-inherent advantages, challenges, and pitfalls. The aim of this study was to compare two techniques to measure PWV, to assess their agreement, and interchangeability. In 780 (female = 49.4%) healthy children and adolescents (mean age: 11.61 +/- 2.11 years), PWV was obtained with two different techniques. Ultrasound-measured local PWV (PWV beta) at the carotid artery was graphically compared by a Bland-Altman plot with aortic PWV (aPWV), measured oscillometrically on the brachial artery. Reproducibility was assessed with the concordance correlation coefficient by Lin (rho C). Furthermore, participants were categorized by BMI as normal weight (N) or overweight/obese (O) to identify differences in PWV beta and aPWV caused by an increased BMI. Mean PWV beta was lower (4.01 +/- 0.44 m/s) than mean aPWV (4.67 +/- 0.34 m/s). The two methods differ by mean Delta 0.66 +/- 0.47 m/s (95% CI: 0.62 to 0.69 m/s; p < 0.001). Bland-Altman analysis indicated the 95% limits of agreement (-0.26 to 1.57) without any evidence of systemic difference. Lin's rho C represented a weak concordance between PWV beta and aPWV (rho C = 0.122; 95% CI: 0.093-0.150). There was no difference in PWV beta between N and O, whereas aPWV was higher in O: 4.81 +/- 0.42 m/s than in N: 4.65 +/- 0.32 m/s (p < 0.001). The difference, Delta 0.16 m/s, 95% CI [-0.25; -0.08], was significant, t((121)) = -3.76, p < 0.001, with a medium-sized effect. PWV beta (ultrasound) and aPWV (oscillometry) show a level of disagreement that includes clinically important discrepancies. A discrimination between normal and altered vascular function was possible with aPWV but not with PWV beta