A comparative study of established z score models for coronary artery diameters in 181 healthy Korean children

Ryu, Kyungguk; Yu, Jeong Jin; Jun, Hyun Ok; Shin, Eun Jung; Heo, Young Hee; Baek, Jae Suk; Kim, Young Hwue; Ko, Jae Kon

Abstract

PURPOSE
The aim of this study was to investigate the statistical properties of four previously developed pediatric coronary artery z score models in healthy Korean children.
METHODS
The study subjects were 181 healthy Korean children, whose age ranged from 1 month to 15 years. The diameter of each coronary artery was measured using 2-dimensional echocardiography and converted to the z score in the four models (McCrindle, Olivieri, Dallaire, and Japanese model). Descriptive statistical analyses and 1-sample t tests were performed.
RESULTS
All calculated z scores had P values of â‰¥0.050 using the Kolmogorov-Smirnov test. The one sample t test showed that the mean z scores did not converge to zero except in 1 model, and the mean right coronary artery (RCA) z score was less than zero in all 4 models. The smaller RCA diameter in this study could be associated with the more distal measuring point used to avoid the conal branch. The percentage of subjects with extreme z score values (â‰¥2.0 and â‰¥2.5) for the left main coronary artery (LMCA) seems to be higher in the Dallaire (4.9% and 3.3%) and Japanese models (7.1% and 3.8%).
CONCLUSION
All 4 models showed statistical feasibility of normal distribution. More precise instructions would be needed for the measurement of the RCA. The higher percentage of extreme z scores for the LMCA is compatible with the basic understanding of anatomic variation in the LMCA.