Acute aortic syndrome (AAS) describes a range of severe, painful, potentially life-threatening abnormalities of the aorta.

[7] Causes can include aortic dissection (which is the most common type),[8] intramural hematoma, penetrating atherosclerotic ulcer or a thoracic aneurysm that has become unstable.

[12] Misdiagnosis is estimated at 39% and is associated with delays correct diagnosis and improper treatment with anticoagulants producing excessive bleeding and extended hospital stays.

[12] AAS is life-threatening, with a high mortality rate if appearing acutely, reduced only when diagnosed early and treated by a surgeon with considerable expertise.

[3] If patients survive acute presentation, within three to five years 30% will develop complications and require close follow-up.