Angiography is a type of X-ray used to examine blood vessels. The images created during an angiography are called angiograms.
Blood vessels don't show up clearly on ordinary X-rays, so a special dye is injected into the area being examined. The dye highlights the blood vessels as it moves through them. The medical name for this type of angiography is catheterisation.
Less commonly, angiographies can also be carried out non-invasively using computerised tomography (CT) andmagnetic resonance imaging (MRI). However, the technique used will depend on a number of factors.
Why angiograms are used
The heart is one of the most common areas of the body that needs to be checked using angiography. During coronary angiography, the flow of blood to the heart muscle can be assessed. The procedure can also be used to help diagnose coronary heart disease.
Other conditions that affect blood vessels and the flow of blood through them can also be detected using angiography – for example, aneurysm(where a section of a blood vessel wall bulges due to a weakness in the wall).
Serious arterial disease in the body can cause problems such asstrokes, heart attacks, gangrene and organ failure, so for certain people it's important that circulation problems are investigated.
The images from coronary angiography can be used to help plan treatment for angina and heart attacks. Treatment options include medication or surgery, such as a coronary angioplasty or a coronary artery bypass graft.
Other areas of the body that can be examined using angiography include the:
brain (cerebral angiography)
lungs (pulmonary angiography)
kidneys (renal angiography)
arms or legs (extremity angiography)
The angiography procedure
Angiography is carried out in hospital. It takes between 30 minutes and two hours, depending on the complexity of the investigation. You'll usually be allowed to go home on the same day, although in some cases you may need to stay in hospital overnight.
Most angiographies are planned procedures carried out under local anaesthetic, sometimes with sedation. However, general anaestheticmay be used for young children or if the procedure is particularly complex.
A very thin flexible tube called a catheter is inserted into one of your arteries through a small cut. The artery is usually in your groin or wrist. A radiologist (a doctor who specialises in imaging studies) or cardiologist (heart specialist) will guide the catheter into the area that needs to be examined. The dye, known as a contrast dye or contrast medium, will be injected through the catheter and into the blood vessel. A series of X-ray images will be taken.
Generally, angiography is a safe and painless procedure and the risk of serious complications is low.
There can sometimes be minor bruising where the catheter is inserted. Some people may occasionally have an allergic reaction to the contrast dye, although this can usually be easily treated with medication.
What angiography is used for
Angiography is an imaging technique used to assess the health of your blood vessels and how the blood flows through them.
If you have circulation problems, your doctor may recommend that you have angiography to find out what's causing the problem. The results can also help determine suitable treatment options.
Types of angiography
There are several different types of angiography that can be used depending on which area of the body needs to be examined, including:
head and neck (cerebral angiography)
heart (coronary angiography)
lungs (pulmonary angiography)
arms and legs (extremity angiography)
kidneys (renal angiography)
Cerebral angiography may be used if it's thought that the blood vessels that supply blood to your brain (the carotid arteries) have become narrowed, disrupting the flow of blood. This can be dangerous because it could trigger a stroke or transient ischaemic attack (TIA or mini-stroke).
If you've had a stroke, cerebral angiography can be used to find out if there's a narrowing in the blood vessels. In some cases, it may be able to pinpoint the underlying cause of a stroke.
Cerebral angiography can also help to identify an aneurysm (a bulge in the blood vessel wall in your brain) or a brain tumour. Studying the flow of blood to the tumour can help determine whether it's growing, which can be useful when planning treatment.
Coronary angiography may be used if you've had:
a heart attack – a serious medical emergency, where the blood supply to the heart is severely reduced or suddenly blocked, usually by a blood clot
angina – chest pain that occurs when the blood supply to the heart muscle is restricted
Coronary angiography may also be used if you have a heart condition that requires surgery. It helps to determine the most appropriate type of treatment for you. This could be:
coronary angioplasty – a surgical procedure to widen blocked or narrowed coronary arteries using balloons and stents
coronary artery bypass graft – a surgical procedure to divert blood around narrow or clogged arteries using grafts so that blood flow to the heart is improved
Computerised tomography pulmonary angiography
Computerised tomography pulmonary angiography (CTPA) is often used to help diagnose a pulmonary embolism (a blockage in the pulmonary artery in one of your lungs).
CTPA involves injecting contrast dye into the blood vessels of your lungs and then taking a CT scan. If you have a pulmonary embolism, it will show up on the CT scan as a blockage in the blood flow.
Extremity angiography may be used if it's thought that the blood supply to your leg muscles has become restricted. This is known as peripheral arterial disease and it causes a range of symptoms, the most common of which is painful cramping when walking.
Imaging tests, such as an ultrasound scan or CT scan, may be used instead of angiography to investigate how severe the condition is.
Renal angiography may be recommended if you have symptoms that suggest the blood supply to your kidneys has been blocked in some way.
These symptoms include:
high blood pressure (hypertension) that doesn't respond to treatment with medication
swelling in certain areas of your body, such as your feet, due to a build-up of fluid (oedema)
kidney failure and symptoms of kidney disease, such as itchy skin and blood in your urine
Atherosclerosis is a condition where the arteries become narrowed and hardened due to a build-up of fatty materials, such as cholesterol. The narrowing is often referred to as a plaque.
In the early stages, atherosclerosis doesn't usually cause symptoms, so medical tests such as angiograms are carried out when advanced disease is suspected.
Angiography is usually carried out if the symptoms are severe, or initial tests, such as a stress test, suggest that atherosclerosis is likely.
Angiography can also be used to:
locate the site of internal bleeding
detect blood clots
investigate injuries to organs
plan surgery that involves the blood vessels
How angiography is performed
Depending on the complexity of the investigation, angiography can take between 30 minutes and two hours.
You'll usually be allowed to go home on the same day, although in some cases you may need to stay in hospital overnight.
Angiography is usually a planned procedure. However, it may occasionally be carried out as an emergency – for example, in the case of a heart attack.
For a planned angiography you're likely to have an initial appointment to discuss your health. For example, you may be asked:
about your medical history
whether you have any allergies
whether you're currently taking any medication
You may also have a number of standard tests before having an angiography, including a physical examination and blood tests to check how well organs, such as your kidneys or liver, are working.
Some people choose to take a sedative to help them relax. In this case, you'll be asked not to eat for several hours before the procedure.
Most angiography procedures are carried out using local anaesthetic to numb the area where the catheter is going to be inserted. General anaesthetic is sometimes used for young children.
The procedure will be carried out by a specialist, such as a cardiologist (a doctor who specialises in heart disease) or a radiologist (a doctor who specialises in using imaging studies). A nurse may also be present to assist with the procedure.
An intravenous (IV) line will be inserted into a vein in your arm. It can be used to deliver sedatives or any other medication as required. Electrodes (small, metallic discs) may be placed on your chest to record your heartbeat. A blood pressure monitor may also be attached to your arm.
A small plastic tube called a sheath will be placed into one of your arteries. A catheter (a long, thin flexible tube) is inserted through the sheath and on to the arteries being examined. Depending on the area being examined, the catheter is usually inserted into an artery in your wrist or groin.
X-rays are used to help guide the catheter to the right place. Contrast dye will then be injected through the catheter and a series of X-rays will be taken. This will allow a map of the arteries to be created.
The procedure isn't painful but you may feel a slightly warm sensation, or a mild burning sensation, as the contrast dye moves through your blood vessels. It can take between 30 minutes and two hours to complete the procedure, depending on the complexity of your condition and what the radiologist finds.
In some cases, other procedures can be carried at the same time, such as inserting a balloon or a small tube called a stent through the catheter to open up a narrowed artery. This is known as angioplasty.
Once the procedure has been completed, the catheter is removed and the incision is closed using manual pressure, a plug or a clamp.
Following angiography, you'll be taken to a recovery ward. You'll be asked to lie still for a few hours, to prevent bleeding at the site of the incision.
Most people are able to leave hospital on the same day as the procedure. However, occasionally, it may be necessary for you to stay in overnight for observation. You'll be able to eat and drink as soon as you feel ready to, but it may take eight to 12 hours before you're well enough to resume normal activities.
Depending on what the cardiologist or radiologist finds during the angiography, they may be able to discuss your results with you shortly after the procedure. Alternatively, they may write a report and send it to your GP.
Complications of angiography
Minor complications can occur after an angiography, but serious complications are rare.
Minor complications include:
bleeding or bruising at the site of the incision
infection at the incision site – which may need to be treated with antibiotics
a mild to moderate allergic reaction to the contrast dye – this can usually be controlled using anti-allergy medication
More serious complications can include:
kidney damage (usually temporary)
blood vessel damage requiring further surgery
a serious life-threatening allergic reaction (anaphylaxis) to the contrast dye
These serious complications are rare. For example, an estimated 1 in 1,000 people will have a stroke as a result of having angiography, and approximately 1 in 50,000 to 150,000 people will experience anaphylaxis.
Angiography is recommended when the benefit of having the procedure is believed to outweigh any potential risk.