Atherosclerotic and Degenerative Aortic Aneurysms
The cause of aortic aneurysms is probably related to multiple risk factors which are commonly found in patients with thoracic and abdominal aneurysms. The risk factors identified as potential causes of aortic aneurysms include smoking, hypertension, atherosclerosis, bicuspid aortic valves, and genetic connective disorders (i.e. Marfan’s Syndrome, and Ehlers-Danlos syndrome). Thoracic aortic aneurysms are more likely to occur in men than in women and in patients with chronic obstructive pulmonary disease (COPD). Degenerative aortic aneurysms are the most common type of aneurysms which are found in the aging population. The aortic wall undergoes changes that involve reduction in the structural framework and strength of the aorta. As the diameter of the aorta increases and the wall thickness decreases, the aortic wall stress increases resulting in a higher probability of rupture or dissection. The most common anatomical location for an aortic aneurysm is in the abdomen and secondly in the descending thoracic aorta. Oftentimes, thoracic aortic aneurysms are found incidentally, however some patients may present with non-specific pain or other symptoms related to compression of other organs as a result of the expanding aneurysm. A common scenario which thoracic aortic aneurysms are discovered is on a plain chest x-ray or chest CT scan performed for another diagnosis.
Penetrating Atherosclerotic Ulceration
Atherosclerotic plaques may ulcerate and erode through the layers of the aortic wall resulting in ulceration (see illustration). A majority of the penetrating ulcers will have an associated hematoma (blood collection) in the wall of the aorta. At times it is difficult to distinguish aortic atherosclerotic ulceration from aortic dissection or pseudoaneurysm. However, aortic dissection and pseudoaneurysms can develop from an aortic ulceration. In addition, free aortic rupture can occur with aggressive aortic ulceration. These are commonly found in older patients and are located in the descending thoracic aorta (see illustration). Atherosclerotic ulcerations can also develop in the ascending aorta. Patients can develop chest pain, which should prompt further investigations. Asympomatic atherosclerotic aortic ulcerations can be treated conservatively and followed carefully for aortic enlargement, dissection, or pseudoaneurysm formation.
Allan Stewart, MD
Director, Aortic Surgery Program
Department of Cardiothoracic Surgery
The Mount Sinai Health System
1190 Fifth Ave: Box 1028
Assistant: Debra Segreti