Hypertension Blog

Aortic aneurysms-dilated segments of the aorta-are more common in men ages 50 to 70. Hypertension increases the risk of a patient developing an aortic aneurysm by accelerating atherosclerosis in peripheral blood vessels. If an aortic aneurysm is larger than 6 mm in diameter, it has a 50% chance of rupturing within a year.

Pathophysiology

An aortic aneurysm results from atherosclerotic plaque formation on the aorta’s walls. These plaques, consisting of lipids, cholesterol, fibrin, and other debris, cause degenerative changes in the aorta’s medial layer. The aorta loses elasticity and becomes weak. The pulsatile flow of the blood places additional stress on the weakened aorta, causing it to dilate, thus forming an aneurysm.

The growth rate of an aortic aneurysm can’t be determined, but the larger the aneurysm, the greater the risk of rupture. An aneurysm can form anywhere along the aorta. But the most common location is the abdominal aorta below the renal arteries. Typically, an abdominal aortic aneurysm involves the iliac arteries at the point of bifurcation.

Aneurysms are divided into two classifications: true aneurysms and false aneurysms. In a true aneurysm, at least one layer of the aorta remains intact. One-fourth of true aneurysms occur in the thoracic region and three-fourths occur in the abdominal region. A true aneurysm may be a fusiform or saccular dilation .

A false aneurysm is a disruption of all three layers of the aorta. This condition results in blood leakage into a contained area.

The rupture of an aortic aneurysm is a life­threatening complication. If the rupture causes bleeding into the retroperitoneal space, it may be stopped by compression from the nearby organs. Bleeding into the abdominal cavity is fatal.