An enlarged artery in the heart is also known as a coronary artery aneurysm, with the word aneurysm describing abnormal dilation or out-pouching arising in a weakened or diseased part of the vessel. Traditional cardiovascular risk factors like high blood pressure, high lipid levels, and smoking are associated with the development of coronary artery aneurysms, though these risks more often result in arterial stenosis (vessel narrowing). Aneurysms of the coronary arteries are at risk for clotting or rupture which could lead to a heart attack, but the likelihood of a serious complication arising from a coronary artery aneurysm is unknown. Your doctor may consider additional risk factors (like artery narrowing in other places) when recommending treatment for your aneurysms. Treatment typically consists of either blood-thinning medication or surgery.