An aortic dissection is a tear in the inner lining of the aorta. This tear allows blood to flow through the walls of the aorta rather than remaining in the central channel (lumen). The two major types of aortic dissection, type A and type B, are defined by the location of the tear.
- Type A dissection—The tear begins in the ascending aorta and progresses throughout the vessel, often extending as far as the arteries in the leg.
- Type B dissection—The tear is located only in the descending aorta, but may extend into the abdomen.
The distinction between the two types is important, as it guides the management of the disease. Type A requires immediate surgery, to prevent death from stroke, heart attack, congestive heart failure, or bleeding. Type B dissection is considered a medical condition that can be initially treated with aggressive control of blood pressure. Additional treatments are generally reserved for complications resulting from the tear.