Variations in carotid artery intima-media thickness during the cardiac cycle in children.

BACKGROUND

There is paucity of research looking at variations in carotid artery intima-media thickness (CIMT) during the cardiac cycle in children. The aim of this study was to ascertain variations, if any, in CIMT during the cardiac cycle in a population of high-risk children.

METHODS

Forty-nine children aged 6 to 19 years with dyslipidemia and other atherosclerosis-promoting risk factors underwent a carotid ultrasound. CIMT was measured using commercially available, semiautomated edge-detection software. The region of interest was the far wall of the common carotid artery. CIMT was measured at various points during the cardiac cycle using the electrocardiogram (EKG) as a reference. CIMT measurements two frames before, during, and after the QRS complex (end diastole) were analyzed separately (designated as "QRS CIMT") from the other CIMT measurements (designated as "non-QRS CIMT"). Demographics, heart rate, blood pressure, anthropometric measures, lumen diameter, family history, and presence of other atherosclerosis-promoting risk factors were documented.

RESULTS

"QRS CIMT" was significantly thicker than "non-QRS CIMT" (P = .01), with the age group 10 to 14 years showing the most significant variation between "QRS CIMT" and "non-QRS CIMT" (P = .005). CIMT values between right and left carotid arteries differed by 2.5%. Age, systolic blood pressure, and blood glucose were significant predictors of mean CIMT by simple linear regression; systolic blood pressure was the only significant predictor of mean CIMT by stepwise multiple linear regression analysis.

CONCLUSION

CIMT measurements vary during the cardiac cycle in children. It is thicker during the QRS complex on EKG. Carotid ultrasound should be performed with an EKG, and CIMT should be measured at the same point on the EKG to overcome this variation. Furthermore, we recommend that CIMT be measured at the R-wave on EKG because this is an easily discernible point in the cardiac cycle.