The aorta is the largest artery in the body and delivers the entire blood volume. The thoracic aorta arises from the left ventricle of the heart and supplies arterial blood to the organs and tissues of the head, upper extremities, and thorax before it arrives at the diaphragm. As it passes through the diaphragm, it becomes the abdominal aorta. The abdominal aorta gives of numerous branches to the abdominal organs and tissues before it divides into the left and right common iliac arteries at the level of the umbilicus.
Abdominal aortic disease or carotid stenosis is quite common, impacting approximately five to twenty percent of Americans, varying with age and other risk factors. Carotid artery disease is caused by atherosclerosis, or the gradual accumulation of calcified plaque in the arterial walls. Plaque can eventually restrict or completely block the flow of blood through the arteries, causing a stroke. Stroke can also occur when a bit of the plaque flakes off and embolizes into the brain.
The biggest risk factors for developing atherosclerosis and carotid artery disease include elevated cholesterol and triglycerides, high blood pressure, smoking, chronic inflammation, and family history.
Because it lies within the abdomen, the abdominal aorta is easily visualized with duplex ultrasound.
Duplex ultrasound examination of the carotid arteries is performed to evaluate for atherosclerotic stenoses and blockages. Carotid arterial duplex ultrasound uses real-time imaging and color Doppler to evaluate the structure and function of the common, external, and internal carotid arteries in about 30 minutes. Because duplex technology allows evaluation of the blood flow as well as the arterial structure, it is considered the gold standard in evaluating the carotid arterial system of the extremities. Because it does not use ionizing radiation, duplex ultrasonography is considered harmless and can be safely used with pregnant patients and patients of any age.There is no required prep and NPO is not necessary.
Common indications for an abdominal aortic ultrasound evaluation include:
- Carotid bruit
- Transient ischemic attack (TIA)
- Aphasia or slurred speech
- Amaurosis fugax
- High-risk individuals – those with diabetes, obesity, smoking history
- Intimal thickening
- Carotid stenosis or blockage
- Subclavian stenosis
- Subclavian steel syndrome
- 93978 – Duplex scan of aorta, IVC, iliac vasculature, or bypass grafts, complete study
- 93979 – Duplex scan of aorta, IVC, iliac vasculature, or bypass grafts; unilateral or limited study