Exercise tolerance test in Kawasaki patients without coronary lesions

Kawasaki disease (KD) is a systemic vasculitis of unknown origin and the leading cause of acquired heart disease in children in developed countries. If untreated, it can cause coronary artery damage in up to 25% of cases. Lifelong follow-up is essential, even for patients without obvious coronary lesions (risk level-I KD). Since some cardiac abnormalities may not be apparent at rest, stress testing offers valuable insight. This study aimed to evaluate exercise tolerance test (ETT) outcomes in children with a history of risk level-I KD compared to a control group.

This case-control study included children aged 5-17 years with documented KD without coronary lesions and at least six months since disease onset. After ethics approval, participants underwent a standardized treadmill test (modified Bruce protocol). A control group of healthy children was also included; however, exact age-matched analysis was not possible due to recruitment constraints.

Sixty children were divided equally into KD and control groups. The KD group had significantly lower mean age, height, weight, and BSA compared to the control group. After adjusting for these variables, most exercise indices showed no significant difference between groups, except for chronotropic incompetence which was more prevalent in the KD group. However, most differences became non-significant after adjusting for age and BMI.

Children with KD generally showed normal exercise tolerance, but a reduced chronotropic response may indicate subtle residual cardiac effects. These findings suggest a potential for subtle cardiac effects and may support the consideration of stress-based evaluation in select patients; however, further larger prospective studies are needed to confirm these observations.