Coronary Artery Z Score Regression Equations and Calculators Derived From a Large Heterogeneous Population of Children Undergoing Echocardiography

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 height^2.7. 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.

Keywords: Coronary artery measurements, Z scores, Kawasaki disease