Analysis of Exercise Capacity of Children with Kawasaki Disease by a Coronary Artery z Score Model (ZSP Version 4) Derived by the Lambda-Mu-Sigma Method

Abstract

Objective: To compare exercise capacity measured by direct cardiopulmonary exercise testing (CPET) of children with Kawasaki disease with different coronary artery diameter z scores (CA z score).

Study design: This was a retrospective study that recruited children with Kawasaki disease after the acute stage receiving CPETs determined by CPET with treadmill. CA z score was based on a model using the Lambda-Mu-Sigma method. Max-Z was defined as the maximum z score of the proximal left anterior descending CA (LCA) or right CA (RCA). Children with Kawasaki disease with a Max z <2.0 and ≥2.0 were defined as Kawasaki disease group 1 and Kawasaki disease group 2, respectively.

Results: We recruited 32 boys and 17 girls with a mean age of 12.39 ± 3.61 years. Kawasaki disease group 1 (n = 36) had significantly higher peak metabolic equivalent (peak-MET) and peak rate pressure product (PRPP) than Kawasaki disease group 2 (n-13) (P = .046, P < .001). Max-Z correlated with peak-MET moderately and negatively (P < .001, Spearman rho= - .506). Max-Z correlated with PRPP modestly and negatively (P = .011, Spearman rho= - .360).

Conclusions: Children after Kawasaki disease with a coronary artery Max-Z ≥ 2.0 had significantly lower peak exercise capacity than those with a Max-Z < 2.0. Max-Z might be used as an indicator of CA reserve and exercise capacity during peak exercise after the acute stage of Kawasaki disease.

Keywords: Kawasaki disease; cardiopulmonary exercise test; coronary artery z score; exercise capacity.