Although AD can be painless, most often it is associated with the acute onset of severe, tearing, migratory pain. These symptoms may be associated with unequal extremity blood pressures as well as a changing pulse exam (as the dissection evolves), either hypertension or hypotension, and/or a new murmur of aortic regurgitation. Although the presentation can be dramatic, with associated end-organ complications, such as syncope, cerebrovascular accident, anuria, or ischemic bowel, equally once the acute pain has passed the diagnosis may be subtle. Misdiagnosis of AD as ACS or other conditions such as pulmonary embolus is the rule not the exception. Accordingly, a high index of suspicion and low threshold to perform appropriate imaging studies are critical. The mortality rate associated with AD untreated is estimated at 1 to 2 percent per hour during the first 24 to 48 h and 75 percent at 2 weeks.