Aortic dissection occurs when a tear in the inner wall of the aorta causes blood to flow between the layers of the wall of the aorta, forcing the layers apart. Aortic dissection is a medical emergency and can quickly lead to death, even with optimal treatment.It is more common in males for unknown reasons. Mean age at diagnosis is 63, although all age groups may be affected. Many cases of aortic dissection (40%) lead to death so rapidly that the person does not reach a hospital in time.
If the pain is pleuritic in nature, it may suggest acute pericarditis caused by hemorrhage into the pericardial sac. This is a particularly dangerous eventuality, suggesting that acute pericardial tamponade may be imminent.
The physician must be careful to make the proper diagnosis prior to initiating treatment for myocardial infarction, since the treatment regimen for myocardial infarction can be lethal to an individual presenting with aortic dissection. If treated with thrombolytic therapy, the mortality increases to over 70%, mostly due to hemorrhage into the pericardial sac causing pericardial tamponade.
Of all people with aortic dissection, 40% die almost straight away and do not reach hospital in time. Of the remainder, 1% die every hour, making prompt diagnosis and treatment a priority. Even after diagnosis, 5–20% die during surgery or in the immediate postoperative period. In ascending aortic dissection, if there is a decision that surgery is not appropriate, 75% die within 2 weeks. With aggressive treatment 30-day survival for thoracic dissections may be as high as 90%. The first case of aortic dissection described was in the post-mortem examination. Surgery for aortic dissection was introduced in the 1950s.