Coronary Artery Vasculitis

Coronary artery vasculitis involves inflammatory destruction of the coronary vessel walls, most commonly caused by Kawasaki disease (KD) in children and by Takayasu arteritis or giant cell arteritis (GCA) in adults. In Kawasaki disease, an acute systemic vasculitis of medium-sized muscular arteries, immune-mediated inflammation targets the coronary arterial wall through all three layers (transmural vasculitis). Activated T cells, macrophages, and IgA plasma cells infiltrate the vessel wall, releasing matrix metalloproteinases (MMPs) that degrade the internal elastic lamina and media. This structural weakening leads to coronary artery aneurysm formation in 25% of untreated children, with giant aneurysms (>8 mm) carrying the highest risk of thrombosis, stenosis, and myocardial infarction. Takayasu arteritis is a granulomatous large-vessel vasculitis affecting the aorta and its major branches, including the coronary ostia; inflammation causes intimal proliferation and fibrosis leading to stenosis. Giant cell arteritis primarily affects branches of the external carotid but can involve coronary arteries, causing granulomatous inflammation with multinucleated giant cells and intimal hyperplasia. The clinician evaluates for coronary involvement using echocardiography (serial coronary artery Z-scores in KD), CT angiography, or coronary MRA. Laboratory...