Accelerated thrombotic occlusion of a medium-sized coronary aneurysm in Kawasaki disease by the inhibitory effect of ibuprofen on aspirin.

The fate of coronary artery aneurysms (CAAs) caused by Kawasaki disease depends mainly on their initial size and shape. Small to medium-sized CAAs are known to regress to normal size or decrease in size, with a good outcome. A patient with Kawasaki disease is reported who had a medium-sized CAA prematurely occluded with thrombi during regression, resulting in myocardial ischemia. This event was probably due to simultaneous use of aspirin and ibuprofen. Thus, the concomitant use of ibuprofen should be avoided when aspirin is given as an antiplatelet agent because ibuprofen blocks the platelet inhibition induced by aspirin.