Aortic Disease

There are many different types of thoracic aortic disease that affect the aorta, and in some cases the aortic valve, which require surgical intervention. Congenital problems with the aortic valve or aorta itself (e.g. coarctation) may result in problems that become more apparent during adolescence or adulthood. Inherited diseases can lead to aortic enlargement (aneurysms) or tears (dissections). The process of aging can lead to atherosclerosis of the aorta with involvement of the aortic valve. This can result in valvular stenosis, regurgitation, aneurysm formation and acute dissections.

Complex thoracic aortic disease includes various types of acute and chronic aortic problems. These include aortic root or ascending aortic dilation/aneurysm and aortic arch aneurysm, and acute Type A and Type B aortic dissections.

Aortic Aneurysm

An aortic aneurysm is a weakening in the wall of the aorta, the largest artery in the body. The dilatation typically occurs in a weakened portion of the artery's wall, causing it to bulge outward and enlarge. If left untreated, an aortic aneurysm may rupture, causing serious complications.

Most thoracic aortic aneurysms are caused by atherosclerosis, a condition in which plaque builds up on the inner walls of the arteries, causing them to harden and narrow. Over time, plaque can cause the aorta to stiffen and weaken, leaving it prone to bulges and ruptures. Aneurysms are also associated with a bicuspid aortic valve (in which there are two leaflets instead of the normal three), and connective tissue disorders such as Marfan's syndrome.

Acute and Chronic Aortic Dissection

 Acute aortic dissection is a tear in the inner (intimal) lining of the aorta which can occur in the ascending, aortic arch, or proximal descending aorta. This tear creates a false channel (lumen) that allows blood to flow through the middle (medial) layer of the aorta. The false lumen can extend throughout the thoracic and abdominal aorta. The false lumen can compromise the flow of blood in the true lumen and cause a lack of blood flow to particular organs. This dissection causes a significant weakness in the aortic wall. A possible complication is a rupture of the aortic dissection. The first two weeks of the aortic dissection is defined as acute aortic dissection. However, after two weeks the aortic dissection is classified as a chronic aortic dissection. During the chronic phase patients are monitored closely to track the growth rate of the aorta.

Dissections less than 2 weeks old are referred to acute dissections, those greater than 2 weeks as chronic dissections.

Acute aortic dissections of the ascending aorta are treated emergently with surgery. Chronic ascending aortic dissections are also treated urgently based on the patient's condition. The majority of patients with chronic aortic dissections in the descending aorta can be asymptomatic and treated conservatively.

Type A aortic dissections involve the ascending aorta and are likely seen in patients with a history of elevated blood pressure, bicuspic aortic valve disease, connective tissue disorders, and ascending aortic aneurysms.

Type B aortic dissections involve a tear in the intimal lining   located beyond the subclavian artery, but can also be located in the aortic arch. Many of these patients present with elevated blood pressure and a history of atherosclerosis and cigarette smoking.