Thoracic Aneurysm & Dissection

Open and endovascular approaches to aortic arch and thoraco-abdominal aorta

Aortic aneurysms and dissections that involve the branch vessels in the arch or perivisceral aorta are among the more challenging conditions faced by our patients. Because these segments of the aorta involve these critically important branch vessels, they are not amenable to treatment with standard endovascular devices. Open surgical repair is a complex endeavor as flow must be maintained during the reconstruction. Advances in endovascular stent graft technology as well as refinements in the operative techniques used for open surgical repair have expanded our ability to treat these patients. Endovascular and open surgery each have their advantages and disadvantages, and a choice between which approach is best for each patient requires expertise with both techniques. We have recently initiated the UW Multi-disciplinary Thoracic Aortic Program (UW MTAP) at UWMC-Montlake to address this specific need.

Aortic aneurysms

An aortic aneurysm is an abnormal bulge in the wall of the aorta.  If the aneurysm continues to expand, it can rupture.  This can cause life-threatening internal bleeding.  Aneurysms can be caused by atherosclerosis, or “hardening of the arteries.” In atherosclerosis, the buildup of fat and cholesterol causes the aortic wall to break down and become weak. Patients with Marfan syndrome, a condition resulting in abnormal fibrillin, commonly develop aortic aneurysms. Ehlers-Danlos syndrome, a collagen disorder, also causes similar clinical findings in some patients. Other disorders associated with aortic aneurysms include Turner’s syndrome, polycystic kidney disease, Loeys-Dietz syndrome, syphilis, arteritis, and traumatic injury (1).

Root aneurysms

The aortic root consists of the aortic valve and the openings for the coronary arteries (the coronary ostia). The aortic valve has three flaps (or cusps) surrounded by a fibrous ring (the annulus).  If an aneurysm develops in the aortic root, the aorta can dilate and the aortic valve can leak.

Ascending aneurysms

Ascending aorta is the portion of the aorta closest to the heart.  The ascending aorta begins at the heart’s left ventricle and extends to the aortic arch, or the bend in the aorta.

Arch aneurysms

The Aortic arch, or bend in the aorta gives off branches to the head and arms.

Thoracoabdominal aortic aneurysm

Thoracoabdominal aneurysms have continuous dilation of the descending thoracic aorta and extending into the abdominal aorta.Open TAAA Repair Education

• Post-op CT scan from a woman treated with a custom made branched endograft for an extent 2 thoracoabdominal aortic aneurysm in the B-TEVAR IDE study. This minimally invasive technique utilized only access from the femoral arteries.

Aortic dissections

The inner layer (intima) of the aorta tears and blood passes through this separation through the aortic wall.  The separation of the layers of the aortic wall produces a false channel (lumen), which spirals throughout a portion or commonly, the entire length of the aorta.

Type A Aortic Dissection

– “A” means the ascending aorta is involved.

• Post-operative CT scan from a patient treated emergently with an arch replacement for an acute type A aortic dissection. He went on to have a single-branched stent graft placed in his descending thoracic aorta as part of a clinical trial. In appropriate candidates, aggressive treatment with a combination of open and endovascular therapy following aortic dissection allows the aorta to “remodel” and limits future aortic-related morbidity

Type B Aortic Dissection

– “B” means the decending aorta is involved.  Type B aortic dissection occurs when there is an intimal tear present beyond the subclavian artery. However, this tear can also form in the aortic arch. The false channel can develop distally into the descending and abdominal aorta.

• The Role of Thoracic Endovascular Repairin Chronic Type B Aortic Dissection

Intramural hematoma and acute aortic syndrome (AAS)