Angiography is the x-ray study of blood vessels. An angiogram uses a dye to make the blood vessels visible under x ray. Angiography is used to detect abnormalities or blockages in the blood vessels (occlusions) throughout the circulatory system and in some organs.

The procedure is commonly used to identify atherosclerosis; to diagnose heartdisease; to evaluate kidney function and detect kidney cysts or tumors; to detect an aneurysm (an abnormal bulge of an artery that can rupture), tumor, blood clot, or arteriovenous malformations (abnormals tangles of arteries andveins) in the brain; and to diagnose problems with the retina. It is also used to map the heart or the brain prior to surgery.

Angiography is performed at a hospital. It requires injecting a contrast dyeinto the blood vessels, making them visible to x ray. The dye is injected byarterial puncture. The puncture is usually made in the groin area, armpit, inside elbow, or neck. After being cleaned with an antiseptic agent andinjected with a local anesthetic, a small incision is made in the skin. A needle containing an inner wire called a stylet is inserted through the incision. When the radiologist has punctured the artery with the needle, the stylet is removed and replaced with another long wire called a guide wire.

The guide wire is fed through the outer needle and threaded through the artery to the area requiring angiographic study. Once it is in position, the needle is removed and a catheter is slid over the length of the guide wire until it to reaches the area of study. The guide wire is removed and the catheter isleft in place in preparation for the injection of the dye.

The dye is either injected with a syringe or with an automatic injector connected to the catheter. The injection causes some mild to moderate discomfort,but it is usually brief. To view the area of study from different angles or perspectives, the patient may be asked to change positions, and subsequent dyeinjections may be administered.

Throughout the dye injection procedure, x-ray pictures and/or fluoroscopic pictures (moving x rays) are taken. Because of the high pressure of arterial blood flow, the dye dissipates quickly, so pictures must be taken rapidly.

Once x rays are complete, the catheter is carefully removed. Pressure is applied to the puncture site for 10-20 minutes so the arterial puncture can reseal itself. A pressure bandage is then applied.

Most angiograms follow the general procedures outlined above, but vary slightly depending on the area of the vascular system being studied.

After an angiography, a person may stay in the hospital overnight. Otherwise,the patient is kept under close observation for at least 6-12 hours before being released. The patient's blood pressure and vital signs are monitored andthe puncture site observed closely. Pain medication may be prescribed, and acold pack is applied to the puncture site to reduce swelling. The puncture site is normally sore and bruised for several weeks. A hematoma, a hard mass created by broken blood vessels, may develop. It should be watched carefully,as it may indicate continued bleeding of the puncture site.

Because angiography involves puncturing an artery, internal bleeding or hemorrhage are possible complications of the test. As with any invasive procedure,infection of the puncture site or bloodstream is a risk, but this is rare.

A stroke or heart attack may be triggered by an angiogram if blood clots or plaque on the inside of the arterial wall are dislodged. The heart may also become irritated by the movement of the catheter through its chambers during lung and heart angiography procedures.

Patients who are allergic to the dye used in angiography may experience symptoms such as swelling, difficulty breathing, heart failure, or a sudden drop in blood pressure.

Angiography involves minor exposure to radiation. Unless the patient is pregnant, or multiple tests are required, the small dose of radiation from a single procedure poses little risk.

Angiography patients should rest for 2-3 days after the procedure. Patients who experience continued bleeding or abnormal swelling of the puncture site, sudden dizziness, or chest pains should seek medical attention immediately.

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