Cardiac Valvular Lesions due to Kawasaki Disease: A Japanese Nationwide Survey.

Objectives To clarify the characteristics of valvular lesions after Kawasaki disease with a Japanese nationwide survey. Study design Among 137 026 patients in the nationwide Japanese surveys between 2007 and 2016, 290 (0.2%) with valvular sequelae were investigated by questionnaires. Results Among the 290 patients with valvular sequelae, mitral regurgitation (MR), tricuspid regurgitation, aortic regurgitation, and pulmonary regurgitation were present 1 month after the development of Kawasaki disease in 183 (63%), 112 (39%), 39 (13%), and 49 (17%) patients, respectively. The numbers of patients with MR during the acute phase and 1 year after developing Kawasaki disease were 208 (72%) and 95 (33%), respectively. MR improved significantly during the late period (P < .0001). Although aortic regurgitation and tricuspid regurgitation also improved significantly (P < .001), pulmonary regurgitation did not change. Ruptured mitral valves chordae tendineae occurred in 6 infants by 6 months of age, within 4 months after the onset of Kawasaki disease. Three patients needed mitral valve plasty, and 1 patient died of acute heart failure. Another 4-month-old girl died of an acute myocardial infarction with MR. In the acute phase, there was a significant difference in the MR severity between the intravenous immunoglobulin-responder group and the intravenous immunoglobulin-resistant group (P < .05). Conclusions The inflammation caused by acute Kawasaki disease affects the function of the mitral valves. Most cases of MR improve with the alleviation of inflammation. Severe MR may have decreased with the development of treatment for acute vasculitis. However, ruptured mitral valves chordae tendineae rarely occurs in infants younger than 6 months old, within 4 months after Kawasaki disease.