Aortic Aneurysm Types and Classification

Aortic Aneurysm

• An aneurysm is a localized sac or dilation formed at a weak point in the wall of the aorta.
• Aneurysms can be classified by their shape or form, with the most common forms being saccular or fusiform.
• Saccular aneurysm projects from one side of the vessel only, while a fusiform aneurysm develops when an entire arterial segment becomes dilated.
• Mycotic aneurysms are very small aneurysms due to localized infection.

Thoracic Aortic Aneurysm

• Approximately 85% of thoracic aortic aneurysms are caused by atherosclerosis.
• Thoracic aortic aneurysms occur most frequently in men between 40 and 70 years old.
• The thoracic area is the most common site for a dissecting aneurysm.
• About one-third of patients with thoracic aneurysms die of rupture.

Clinical Manifestations of Thoracic Aortic Aneurysm

• Symptoms are variable and depend on how rapidly the aneurysm dilates and how it affects surrounding intrathoracic structures.
• Pain is the most prominent symptom, usually constant and boring, but may occur only when the person is supine.
• Some patients are asymptomatic.

Assessment and Diagnostic Findings of Thoracic Aortic Aneurysm

• Diagnosis is principally made by chest x-ray, transesophageal echocardiography, and CT.
• Compression of large veins in the chest can lead to dilation of superficial veins, edema, and cyanosis.
• Pressure against the cervical sympathetic chain can result in unequal pupils.

Medical Management of Thoracic Aortic Aneurysm

• In most cases, an aneurysm is treated by surgical repair.
• General measures such as controlling blood pressure and correcting risk factors may be helpful.
• Controlling blood pressure is important in patients with dissecting aneurysms.
• Medications such as hydralazine, esmolol, atenolol, and timolol are used to control blood pressure.
• Propranolol is used to reduce cardiac contractility.

Abdominal Aortic Aneurysm

• The most common cause of abdominal aortic aneurysm is atherosclerosis.
• The condition is more common among Caucasians, affects men four times more often than women, and is most prevalent in elderly patients.
• Most abdominal aortic aneurysms occur below the renal arteries (infrarenal aneurysms).
• Untreated, the eventual outcome may be rupture.

Pathophysiology of Aortic Aneurysm

• All aneurysms involve a damaged media layer of the vessel.
• Risk factors include genetic predisposition, smoking, and hypertension.
• More than one-half of patients with aneurysms have hypertension.

Clinical Manifestations of Abdominal Aortic Aneurysm

• About two-fifths of patients with abdominal aortic aneurysms have symptoms, while the remainder do not.
• Symptoms include feeling a pulsating mass in the abdomen, or feeling an abdominal mass or abdominal throbbing.