Factors associated with development of coronary artery aneurysms after Kawasaki disease are similar for those treated promptly and those with delayed or no treatment

Background While the risk is reduced, patients may develop coronary artery (CA) aneurysms after Kawasaki disease (KD) despite receiving intravenous immunoglobulin (IVIG) within 10 days of symptom onset. Risk factors for CA aneurysms may differ compared to those patients with delayed or no treatment. Methods Patients diagnosed with KD between 1990 and 2013 were included. Patients with maximum coronary artery z-scores > 5 were classified as having CA aneurysms. Separate multivariable regression models were used to determine factors associated with CA aneurysms for those with versus without prompt treatment. Results Of 1358 patients included, 83% (n = 1126) were treated with IVIG within 10 days and 5% (n = 53) developed CA aneurysms. Patients who had delayed (> 10 days) or no IVIG treatment were at increased odds of developing CA aneurysms (OR: 3.1,95% CI: 1.9–5.1, p < 0.001). For patients with prompt treatment with IVIG, factors associated with increased odds of CA aneurysms were: longer duration of fever prior to treatment (OR: 1.2/day, p = 0.04), age < 1 year (OR: 3.9, p = 0.001), higher pre-IVIG white blood cell count (OR: 1.05/× 10⁹/L, p = 0.007), lower hemoglobin (OR: 1.4/g/L, p = 0.004) and non-response to initial IVIG treatment (OR: 2.5, p < 0.001). For patients with delayed or no treatment, factors associated with increased odds of CA aneurysms were: males (OR: 5.4, p = 0.009), age < 1 year (OR: 29.9, p < 0.001), and higher platelet count (OR: 1.4/100 × 10¹²/L, p = 0.001). Delayed treatment with IVIG did not reduce the risk of CA aneurysms (OR: 1.9, p = 0.28), and total duration of fever was not associated with CA aneurysms for this group (OR: 1.04/day, p = 0.16). Conclusions Factors associated with the development of CA aneurysms are generally similar for those treated promptly versus those with delayed or no treatment. For those with delayed diagnosis, treatment with IVIG does not appear to be effective to prevent CA aneurysms.