Importance

American Heart Association guidelines recommend echocardiography in Kawasaki disease at baseline, 1 to 2 weeks, and 4 to 6 weeks after treatment to detect coronary artery abnormalities. However, these examinations are expensive and may require sedation in young children, which is burdensome and carries some risk.

Objective

To assess the benefit of additional echocardiographic imaging at 6 weeks in patients with uncomplicated Kawasaki disease who had previously normal coronary arteries.

Design, setting, and participants

This is a retrospective review of patients with Kawasaki disease who were cared for between 1995 and 2014 in 2 academic pediatric referral practices Eligibility criteria included receiving intravenous immunoglobulin treatment for acute Kawasaki disease at a center; the absence of significant congenital heart disease; available echocardiographic measurements of both the right and left anterior descending coronary arteries at 10 days or less after diagnosis (baseline), 2 (±1) weeks, and 6 (±3) weeks of illness; and normal coronary arteries at baseline and 2 weeks, defined as maximum coronary artery z scores less than 2.0 and no distal aneurysms. Data analysis was completed from March 2015 to November 2015.

Main outcomes and measures

The number of patients with right coronary artery or left anterior descending coronary artery z scores of 2.0 or more at 6 weeks.

Results

The median age of the 464 included patients was 3.3 years (interquartile range, 1.8-5.4 years); 264 (56.9%) were male, 351 of 414 for whom data were available (84.8%) had complete Kawasaki disease, and 66 (14.2%) received additional intravenous immunoglobulin treatment. At 6 weeks of illness, 456 patients (98.3%) who had had normal coronary artery z scores at baseline and 2 weeks continued to have normal z scores. Of the remaining 8 patients (1.7%), the maximum z score within 6 weeks was 2.0 to 2.4 in 5 patients (1.2%), 2.5 to 2.9 in 1 patient (0.2%), and 3.0 or more in 2 patients (0.4% [95% CI, 0.1%-1.5%]). Coronary artery dimensions ultimately normalized in all but 1 patient, who had minimal dilation at 6 weeks (right coronary artery z score, 2.1). Sensitivity analyses using less restrictive cut points (eg, a maximum z score <2.5) or less restrictive timing windows (eg, considering patients with incomplete echocardiographic data within 21 days) gave similar results; in these analyses, 454 to 463 of 464 patients (98% to 99.7%) had coronary artery z scores of less than 2.5 at 6 weeks.

Conclusions and relevance

New abnormalities in coronary arteries are rarely detected at 6 weeks in patients with Kawasaki disease who have normal measurements at baseline and 2 weeks of illness, suggesting that the 6-week echocardiographic imaging may be unnecessary in patients with uncomplicated Kawasaki disease and z scores less than 2.0 in the first 2 weeks of illness.

Background

The natural history of coronary artery aneurysms (CAA) after intravenous immunoglobulin (IVIG) treatment in the United States is not well described. We describe the natural history of CAA in US Kawasaki disease (KD) patients and identify factors associated with major adverse cardiac events (MACE) and CAA regression.

Methods and Results

We evaluated all KD patients with CAA at 2 centers from 1979 to 2014. Factors associated with CAA regression, maximum CA z‐score over time (zMax), and MACE were analyzed. We performed a matched analysis of treatment effect on likelihood of CAA regression. Of 2860 KD patients, 500 (17%) had CAA, including 90 with CAA z‐score >10. Most (91%) received IVIG within 10 days of illness, 32% received >1 IVIG, and 27% received adjunctive anti‐inflammatory medications. CAA regression occurred in 75%. Lack of CAA regression and higher CAA zMax were associated with earlier era, larger CAA z‐score at diagnosis, and bilateral CAA in univariate and multivariable analyses. MACE occurred in 24 (5%) patients and was associated with higher CAA z‐score at diagnosis and lack of IVIG treatment. In a subset of patients (n=132) matched by age at KD and baseline CAA z‐score, those receiving IVIG plus adjunctive medication had a CAA regression rate of 91% compared with 68% for the 3 other groups (IVIG alone, IVIG ≥2 doses, or IVIG ≥2 doses plus adjunctive medication).

Conclusions

CAA regression occurred in 75% of patients. CAA z‐score at diagnosis was highly predictive of outcomes, which may be improved by early IVIG treatment and adjunctive therapies.

The natural history of coronary artery aneurysms (CAA) after intravenous immunoglobulin (IVIG) treatment in the United States is not well described. We describe the natural history of CAA in US Kawasaki disease (KD) patients and identify factors associated with major adverse cardiac events (MACE) and CAA regression. We evaluated all KD patients with CAA at 2 centers from 1979 to 2014. Factors associated with CAA regression, maximum CA z-score over time (zMax), and MACE were analyzed. We performed a matched analysis of treatment effect on likelihood of CAA regression. Of 2860 KD patients, 500 (17%) had CAA, including 90 with CAA z-score >10. Most (91%) received IVIG within 10 days of illness, 32% received >1 IVIG, and 27% received adjunctive anti-inflammatory medications. CAA regression occurred in 75%. Lack of CAA regression and higher CAA zMax were associated with earlier era, larger CAA z-score at diagnosis, and bilateral CAA in univariate and multivariable analyses. MACE occurred in 24 (5%) patients and was associated with higher CAA z-score at diagnosis and lack of IVIG treatment. In a subset of patients (n=132) matched by age at KD and baseline CAA z-score, those receiving IVIG plus adjunctive medication had a CAA regression rate of 91% compared with 68% for the 3 other groups (IVIG alone, IVIG ≥2 doses, or IVIG ≥2 doses plus adjunctive medication). CAA regression occurred in 75% of patients. CAA z-score at diagnosis was highly predictive of outcomes, which may be improved by early IVIG treatment and adjunctive therapies.