Long-Term Outcome of Kawasaki Disease Complicated by a Large Coronary Aneurysm

Kawasaki disease was first identified in Japan by Tomisaku Kawasaki in 1967,1) and has now been described worldwide. In Korea, the annual incidence of KD was 194.7 per 100000 children in 2014, and the coronary aneurysm rate was 1.7%.2) Kawasaki disease (KD) is an acute febrile disease of unknown etiology. It causes systemic inflammation of vessels through the whole body and especially affects coronary arteries in children younger than 5 years of age.3) The disease leads to coronary artery aneurysms in ≈25% of untreated cases. Treatment within 10 days of illness onset with high dose intravenous immunoglobulin (IVIG) and aspirin has proven effective in dramatically reducing the risk of cardiac complications. However, approximately 20% of patients who require a second dose of IVIG for KD do not adequately respond to this treatment and require additional medications such as corticosteroid or infliximab.4)5) The natural history of coronary arterial inflammation in KD was demonstrated to occur through 3 mechanisms (Fig. 1):3)6) 1) no coronary artery changes, 2) mild, transient dilatation that resolves within 4-6 weeks, 3) necrotizing arteritis that forms an aneurysm. Coronary arterial aneurysm can progress to subacute/chronic vasculitis, luminal myofibroblastic proliferation, and laminar nonocclusive thrombosis. Its phenotypes are myocardial infarction, possible progression to a normal luminal dimension, or further progression to complex stenosis with calcification.3)6) In 1% of cases with such damage, diffuse dilatation of the coronary arteries can progress to a giant aneurysm. The progression to giant aneurysm increases the risks of acute thrombosis and long-term myocardial ischemia.7) The severity of coronary artery luminal lesions determines the risk range for long-term management. Such risk assessment depends on the patient’s maximal Z score in any branch by echocardiography or coronary angiography/angio-computed tomography. Large/giant aneurysms are defined as Z score ≥10 or absolute inner diameter ≥8 mm, and medium aneurysms are those with a Z score ≥5 to <10 or an absolute inner diameter <8 mm.3)5) The treadmill exercise test is the least sensitive method to detect myocardial ischemia in patients with KD.8) Stress myocardial scintigraphy has been shown to be useful for risk stratification.8) Long-Term Outcome of Kawasaki Disease Complicated by a Large Coronary Aneurysm Jo Won Jung, MD Division of Pediatric Cardiology, Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Korea