Aortic dissection

Aortic dissection occurs when a tear in the inside of the aorta causes blood to flow between the layers of the wall of the aorta, forcing the layers apart. In most cases this is associated with a sudden onset of severe chest or back pain, often described as "tearing" in character. 
Also, vomiting, sweating, and lightheadedness may occur. Other symptoms may result from decreased blood supply to other organs such as stroke or mesenteric ischemia. Aortic dissection can quickly lead to death as a result of not enough blood flow to the heart or rupture of the aorta.
Aortic dissection is more common in those with a history of high blood pressure, a number of connective tissue diseases that affect blood vessel wall strength such as Marfan syndrome, a bicuspid aortic valve, and previous heart surgery.