Variations in carotid artery intima-media thickness during the cardiac cycle in children
Spencer Menees1, Danna Zhang, Joseph Le
1University of Missouri-Kansas City School of Medicine, Kansas City, Missouri, USA.
Insights
Carotid artery intima-media thickness (CIMT) varies during the cardiac cycle in children, being thicker during the QRS complex. Standardizing CIMT measurements with an EKG, ideally at the R-wave, is recommended for accuracy.
Area of Science:
- Pediatric Cardiology
- Vascular Ultrasound
- Cardiovascular Research
Background:
- Limited research exists on carotid artery intima-media thickness (CIMT) variations during the cardiac cycle in pediatric populations.
- High-risk children with dyslipidemia and other atherosclerosis risk factors were studied to address this research gap.
Purpose of the Study:
- To investigate and quantify the variations in CIMT throughout the cardiac cycle in children.
- To determine if CIMT measurements differ based on specific points in the cardiac cycle.
Main Methods:
- Carotid ultrasound was performed on 49 children (ages 6-19) with cardiovascular risk factors.
- Carotid artery intima-media thickness (CIMT) was measured using semiautomated software, synchronized with the electrocardiogram (EKG).
- Measurements were analyzed comparing the QRS complex (end diastole) to other cardiac cycle phases ('QRS CIMT' vs. 'non-QRS CIMT').
Main Results:
- 'QRS CIMT' was significantly thicker than 'non-QRS CIMT' (P = .01), particularly in the 10-14 year age group (P = .005).
- Systolic blood pressure was identified as a significant predictor of mean CIMT.
- Minor differences (2.5%) were observed between right and left carotid artery measurements.
Conclusions:
- Carotid artery intima-media thickness (CIMT) exhibits significant variation during the cardiac cycle in children.
- Standardizing CIMT measurement timing with an electrocardiogram (EKG), specifically at the R-wave, is crucial for consistent and accurate assessments.
- This standardization is recommended to mitigate measurement variability in pediatric cardiovascular risk assessment.
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.
