Large-vessel vasculitis affects the body’s largest arteries, such as the aorta (the main artery carrying blood from the heart) and its major branches. Because these vessels supply blood to many organs, inflammation can reduce blood flow and cause damage in areas like the head, arms, or kidneys. The most recognized forms are Giant Cell Arteritis (Temporal Arteritis) and Takayasu Arteritis. A related condition, Polymyalgia Rheumatica, often overlaps with Giant Cell Arteritis.