What Is an Dissecting Aneurysm

In dissecting aneurysm the part of the wall of the aorta (tunica media) splits into two layers creating a false lumen in the wall. Entry of blood into this cavity can occlude branches of the aorta at that site. The thoracic aorta is the most common artery affected in this process.

What is the difference between an aneurysm and dissection?

Aneurysms can occur in any vessel, most notably in the brain, heart, thoracic aorta, and abdominal aorta. A dissection is a tear of the inside layer of a blood vessel wall that allows blood to flow between the layers that make up the vessel wall and separate these layers.

What is the most common site for dissecting aneurysm?

The most common site of dissection is the first few centimeters of the ascending aorta, with 90% occurring within 10 cm of the aortic valve. The second most common site is just distal to the left subclavian artery. Between 5% and 10% of dissections do not have an obvious intimal tear.