Atherosclerosis is a disease where fatty deposits build up in the arteries and restrict blood flow. It is the leading cause of heart attacks and occurs when cholesterol builds up on the inner walls of the arteries that supply the heart. Over time, this buildup narrows the arteries and reduces blood flow. If a blocked artery completely closes off, it can cause a heart attack. Risk factors include high blood pressure, smoking, obesity, lack of exercise, diabetes, and high cholesterol. Treatment options depend on the severity and can include lifestyle changes, medications, angioplasty, stents, or bypass surgery to reroute blood flow around blocked arteries.