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 the most common medical emergency condition of the aorta and can quickly lead to death, even with optimal treatment.
Individuals with aortic dissection develop sudden and severe pain which may be described as tearing, stabbing, or sharp in character. Frequently, individuals feel the pain migrating as the dissection extends down the aorta. The location of dissection determines the location of pain.
Hypertension is the most important risk factors for aortic dissection and is present in 40%-75% of the patients. The incidence of aortic dissection is more in males especially in elderly males than females for reasons yet not known. Also, even though all age groups are vulnerable, the mean age of patients at diagnosis is 63.
Aortic dissections are classified on the basis of the intimal tear according to the Stanford classification system. Type A aortic dissection involves the ascending thoracic aorta and may extend into the descending aorta. Type A dissections account for 60%-70% of cases and generally requires immediate surgical intervention. If left untreated, Type A dissections may lead to death in 50% cases within 48 hours. On the other hand, in a type B dissection, the intimal tear is located distal to the
left subclavian artery. It accounts for 30%-40% of cases and can often be treated medically unless an extension of dissection causes complications that require surgical intervention.
Of all people with aortic dissection, almost 40% patients die even before reaching the hospital . 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 the surgery is not appropriate, 75% die within 2 weeks. With aggressive treatment, 30-day survival for thoracic dissections may be as high as 90%.