Angiography, angioplasty & stenting

Angiography is a type of imaging technique that uses contrast dye and X-rays to visualise the blood vessels, in order to diagnose blockages or other problems. An angiogram can refer to the images taken during an angiography, or to the actual procedure of angiography. This technique was pioneered more than eight decades ago by Dr Egas Moniz, a Portuguese neurologist who used it to diagnose blood vessel diseases of the brain.

What is the process of angiography
The angiogram involves several steps. The patient is given a light sedative to help them relax, and an IV (intravenous) line is inserted in groin. A catheter (a thin hollow tube) is placed through the IV and carefully moved to the blood vessels of interest. Contrast dye (a special fluid that shows up well on x-ray) is injected into the IV and through the catheter. X-rays images are taken to see how the dye flows through the vessel. In this way, blockages or other abnormalities can be detected.

Catheters used in angiography are small hollow tubes that can be bent different directions to navigate through the veins & arteries of the body.

Why is angiography performed?
The main reason for performing an angiogram is to detect a variety of blood vessel disease including:

blockages or narrowing of blood vessels (stenosis)
abnormal enlargement of blood vessels (aneurysms)
malformed arteries (vascular malformations)
clots in the veins of the leg (deep vein thrombosis) or in the lungs (pulmonary embolism)

For more specific information about a particular condition, see the related articles at the bottom of this page.

What to expect on the day
Angiography is usually a day procedure, meaning that the patient should be able to return home the same day as the procedure. The patient should not eat or drink anything for 8 hours prior to the procedure.

During the procedure the patient may be given a sedative, but they will be awake during the procedure. There may be some discomfort when the IV is placed in the groin. The whole procedure can last from one to several hours, depending on what is found and whether treatment is given.

After the procedure, the catheter is removed, and firm pressure is placed is placed at the site to prevent bleeding. You may be asked to lie on your back for several hours to avoid bleeding.

Risks of angiography
Angiography is a minimally invasive procedure, and is considered quite safe. Complications are uncommon, but may include:

Bleeding or bruising at the IV site
Infection of the IV site
Allergic reaction to the contrast dye
Rarely, a blood clot resulting in tissue damage or stroke

Benefits of angiography
Angiography is one of the best ways to examine the state of the blood vessels, due to its simplicity and low complication rate. Alternatives include doppler ultrasound and CT (computerised tomography) angiography. The problems with these alternatives are that the accuracy of doppler ultrasound depends significantly on the experience of the ultrasonographer, and the significant radiation exposure to the patient in CT angiography. Angiography has the added benefit of being able to offer diagnosis and treatment in the same procedure. For the majority of patients, angiography is most appropriate investigation.

Angioplasty & Stenting
If a blockage of a blood vessel is detected, this can be treated during the angiography procedure using a number of methods. Angioplasty (or ballooning) uses a special catheter with a small deflated balloon at one end. Under x-ray guidance, the catheter is passed to the site of the blocked vessel. The balloon is then inflated to open up the vessel. This pushes the atherosclerotic plaque that is blocking the vessel to the sides of the vessel walls, effectively unblocking the artery. The balloon can then be deflated and the catheter removed.

There is usually a good success rate, as defined by the blood vessel remaining patent following angioplasty. This depends on the size and complexity of the stenosis, the skill of the operator and the location of the stenosis. Complications occur in 2-3% of patients, but are usually minor and the same as the risks of angiography.

Sometimes a stent is used after angioplasty to prevent the vessel from narrowing again. A stent is a small metal mesh that is designed to support the vessel walls mechanically. The stent sits on top of a deflated balloon catheter, which is inserted so that the ends of the stent cover the entirety of the stenosis. When the ballon is inflated, the stent expands, supporting the vessel walls. The stent remains in place even after the balloon catheter is removed, and eventually becomes integrated into the vessel wall. The success rate is very high. Complications include those of angiography as well as formation of a clot or scar tissue within the stent. This may require re-stenting later on. The drug-eluting stent is a new type of stent that has been developed to reduce the risk of scar tissue stenosis within the stent. This is currently only used in heart procedures.

In angiography, a balloon on the end of a catheter is inflated, pushing the plaque to the side of the vessel. In stenting, a metal stent is expanded by the balloon and remains inside the vessel.