Angiography

Definition

Angiography (also known as an Angiogram) is the x-ray visualization of the internal anatomy of the heart and blood vessels after the intravascular introduction of radiopaque contrast medium (dye).

Description

The procedure is used to help diagnose conditions such as myocardial infarction, vascular occlusion, calcified atherosclerotic plaques, cerebrovascular accident, portal hypertension (e.g., from liver failure), kidney neoplasms, renal (kidney) artery stenosis as a causative factor in hypertension, pulmonary emboli, and congenital and acquired lesions of pulmonary vessels.

A dye, called the contrast medium, may be injected into an artery or vein or introduced into a catheter inserted in a peripheral artery and threaded through the vessel until its position is either in the heart or at the beginning of the arteries supplying the heart. Testing for hypersensitivity to the dye occurs before the substance is used, as there may be an allergic reaction in some patients. After the procedure, the patient is monitored for signs of bleeding, and bed rest for a number of hours is indicated.

Procedure

Carotid angiography is sometimes performed on patients suffering from transient ischemic attacks (symptoms of stroke lasting less than 24 hours) to see whether there is a blockage or substantial narrowing in one of the carotid arteries (in the neck), which supply blood to the brain.

Cerebral angiography is used to demonstrate the presence of an aneurysm within the brain or to help visualize a brain tumor prior to surgery.

An angiogram, or angiography, of the coronary arteries, often combined with cardiac catheterization, is carried out to identify the sites of narrowing or blockage in arteries, which may be treated by coronary artery bypass or balloon angioplasty.

Contrast medium is usually injected into the vessel to be examined through a fine catheter (flexible plastic tube) inserted into the femoral artery at the groin, the brachial artery just over the elbow, or the carotid arteries that run up the neck. To insert the catheter, the skin and tissues around the artery are numbed with local anesthetic and then a needle is inserted through the skin into the artery.

A long, thin wire with a soft tip is inserted through the needle, the needle is removed, and the catheter is then threaded over the wire into the blood vessel. Under x-ray control, the tip of the catheter is further guided into the vessel to be examined and contrast medium is injected. A rapid sequence (or movie) of x-ray pictures is taken so that the flow along the vessels can be studied. Angiography can take from as little as a few minutes to as long as two or three hours.

Although the risk decreases as this procedure becomes increasingly common, there are some risks. The most serious is a heart attack or stroke, which may happen if the catheter dislodges a blood clot or cholesterol deposit in the artery and it travels to the heart, lungs, or brain. Other possible complications include damage to the walls of the heart or blood vessels (rare), swelling, bleeding, or infection at the incision site, and allergic reaction to the contrast medium.