Coronary Artery Z Score Regression Equations and Calculators Derived From a Large Heterogeneous Population of Children Undergoing Echocardiography
published online 12 December 2008.
Background
Clinical decision making in Kawasaki disease relies on measurements of the coronary arteries obtained by 2-dimensional echocardiography. Z scores relating measured values to independent variables are invaluable in ensuring the accurate and consistent treatment of patients with Kawasaki disease.
Methods
The right coronary artery (RCA), left main coronary artery (LMCA), and left anterior descending (LAD) coronary artery were measured in 432 normal digital echocardiograms from a heterogeneous population of normal subjects aged 0 to 20 years. Linear regression analyses were performed relating the measurements to various functions of independent variables, including body surface area (BSA), height, and height2.7. The adjusted R2 and mean square error values were compared for each of the models, and the best model was chosen to create a Z score calculator.
Results
Using the model ln(measurement) = β1 + β2 × ln(BSA), the adjusted R2 values were 0.638, 0.702, and 0.708 for the RCA, LMCA, and LAD coronary artery models, respectively, with mean square error < 0.0402.
Conclusion
The calculation of accurate Z scores for coronary artery measurements in children can be accomplished using the Z-score calculator.
ABSTRACT