Research of Z scores formula of coronary artery diameters in healthy children

Abstract

Objective To research and build the best Z scores formula of coronary artery internal diameters in healthy children. Methods A total of 1 000 healthy children who were outpatients in First Hospital of Jilin University and with normal heart structure by echocardiography were subjected to this study from October 2015 to October 2016. The height, weight and body surface area (BSA) of all children were measured, and the internal diameters of left coronary artery (LCA), left anterior descending (LAD) and right coronary artery (RCA) were measured by SSH-880CV Doppler ultrasound. The differences between different gender in the aspects of LCA, LAD and RCA internal diameters were analyzed by statistical methods. The relation between age, height, weight, BSA and internal diameters of LCA, LAD, RCA were analyzed by linear correlation analysis. The linearity, logarithmic, exponential, power function, quadratic and square root regression model of BSA and coronary artery internal diameters were established. And the best regression model was chosen according to the coefficient of determination R2 value of the regression model. At last, the formula of Z scores for coronary artery internal diameters in healthy children was established according to the best regression model. Results ①There were no significant differences between children with different gender in internal diameters of LCA, LAD and RCA (t=1.834, 1.723, 1.711; P=0.067, 0.085, 0.087). ②Linear correlation analysis showed that age, height, weight as well as BSA all were positively correlated with the internal diameters of LCA, LAD and RCA (LCA: r=0.773, 0.768, 0.735, 0.779, P<0.001; LAD: r=0.779, 0.765, 0.743, 0.783, P<0.001; RCA: r=0.776, 0.772, 0.764, 0.786, P<0.001). And BSA had the strongest correlation with the internal diameters of LCA, LAD and RCA (r=0.779, 0.783, 0.786; P<0.001). ③The values of coefficient of determination R2 in the square root regression models between BSA and the internal diameters of LCA, LAD and RCA were the biggest which were 0.684, 0.685 and 0.687, respectively. So the square root regression models between BSA and the internal diameters of LCA, LAD and RCA were the best regression models which were yLCA=0.317+ 2.162×, yLAD=2.016+ 0.239×, and yRCA=0.177+ 2.023× (all P<0.001) And yLCA, yLAD, yRCA were referred to the internal diameters of LCA, LAD, RCA, respectively; xBSA was referred to the BSA. ④The formulas of Z scores for coronary artery internal diameters in healthy children were established as follows: ZLCA=[xLCA-(0.317+ 2.162×)]/0.243, ZLAD=[xLAD-(2.016+ 0.239×)]/0.215, ZRCA=[xRCA-(0.177+ 2.023×)]/0.236, and xLCA, xLAD, xRCA were referred to the measured values of LCA, LAD and RCA internal diameters, respectively; xBSA was referred to the BSA. Conclusions A valid equation of Z scores for coronary artery diameters which suitable for Chinese children is an ideal index to judge coronary artery abnormalities and is of great significance to guide clinical prevention and treatment of coronary artery abnormalities in children. Key words: Coronary vessels; Coronary artery disease; Body surface area; Z score; Echocardiography; Child