Doctor's Notes on Aortic Aneurysm of the Abdomen and Thorax (Chest)
An aortic aneurysm is an outpouching or bulging of the aorta, which is the largest artery in the human body. Arteries carry blood away from the heart to other parts of the body. Arteriosclerosis is the most common cause of an aortic aneurysm, and smoking is a major risk factor for their development.
An aortic aneurysm may not produce symptoms or signs unless it ruptures. Signs and symptoms can include deep pain in the lower back or flank and abdominal pulsations. Rupture of an aortic aneurysm is a serious emergency. Sudden and severe pain is the most common symptom of a ruptured aortic aneurysm. A ruptured aortic aneurysm causes massive internal bleeding and can be fatal.
Heart Disease : Test Your Medical IQ Quiz

In the U.S., 1 in every 4 deaths is caused by heart disease.
See AnswerREFERENCE:
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.