An 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, and it appears white on the angiogram. The medical name for this type of angiography is a catheter angiogram.

Less commonly, angiographies can also be carried out using magnetic resonance imaging (MRI) and computerised tomography (CT) techniques.

These pages mainly focus on catheter angiograms.

Why angiograms are used

An angiography can help diagnose conditions that affect blood vessels and the flow of blood through them. These include:

• coronary heart disease – the blood flow through the artery that supplies the heart is disrupted because it has become narrowed
• aneurysm – a section of a blood vessel wall bulges outwards due to a weakness in the wall
• atherosclerosis – blood vessels become clogged up with fatty substances, such as cholesterol; an angiography can be used to assess the level of atherosclerosis in specific blood vessels

The image on an angiogram can also be used to help plan surgery that involves the blood vessels, such as a coronary angioplasty, which is sometimes used to treat coronary heart disease.

Read more about what an angiography is used for.

The angiography procedure

An angiography is carried out in hospital. It takes between 30 minutes and two hours, depending on the complexity of the investigation. You will usually be allowed to go home on the same day, although in some cases you may need to stay in hospital overnight.

In most cases, angiographies are planned procedures that are performed under local anaesthetic. However, general anaesthetic may be used if young children need to have the procedure.

A catheter (a very thin, flexible tube) is inserted through a small cut and into one of your arteries, usually in your groin or your leg. A radiologist (a doctor who specialises in imaging studies) will guide the catheter into the area that needs to be examined. The dye (medically known as a contrast dye or contrast medium) is injected through the catheter and into the blood vessel. A series of X-rays is then taken.

Read more about what happens during an angiography.

Safety

An angiography is a generally safe and painless procedure. The risks of serious complications are low.

Sometimes, an angiography can cause minor bruising where the catheter is inserted. Also, some people may occasionally have an allergic reaction to the contrast dye. This is usually easily treated with medication.

Read more about the complications of an angiography.

Aneurysm

An aneurysm is a blood-filled sac that forms in a weakened part of a blood vessel.

Arteries

Arteries are blood vessels that carry blood from the heart to the rest of the body.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood vessels

Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Brain

The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.

Congenital

Congenital means a condition that is present at birth. The condition could be hereditary or develop during pregnancy.

Coronary artery bypass

A coronary (heart) bypass is surgery to redirect the flow of blood around a clogged artery, by creating a new pathway for the blood to travel in.

Cysts

A cyst is a fluid-filled sac or cavity in the body.

Heart

The heart is a muscular organ that pumps blood around the body.

Kidneys

Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.

Veins

Veins are blood vessels that carry blood from the rest of the body back to the heart.

X-ray

An X-ray is a painless way of producing pictures of inside the body using radiation.

An angiography is an imaging technique that can be used to assess the health of your blood vessels and how the blood flows through them.

If you have circulation problems, your GP may recommend that you have an angiography to find out what's causing the problem. The results of an angiography can also help to determine suitable treatment options.

Dense areas of your body such as your bones and, to a lesser extent, certain organs, such as your lungs, absorb X-rays, so they show up as clear white areas on X-ray images. However, conventional X-rays don't produce clear images of blood vessels and blood flow.

During an angiography, a special type of dye (medically known as a contrast dye or contrast medium) is injected into the area where the blood vessels are to be examined. Like your bones and other dense areas of the body, the contrast dye absorbs X-rays.

As the contrast dye moves through your blood vessels, a series of X-rays can be taken to examine how it moves. By tracking its movement, it's possible to identify any problems with the blood vessels, such as blockages or sections that are unusually narrow.

Head and neck

An angiography procedure that's used to study the blood vessels in your head and neck is called a cerebral angiography.

A cerebral angiography may be used if it's thought that the blood vessels supplying 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 a transient ischemic attack (mini-stroke).

If you've had a stroke, a cerebral angiography can be used to assess the extent of the damage to the blood vessels. In some cases, it may be able to pinpoint the underlying cause of a stroke.

A cerebral angiography can also help to identify an aneurysm (a bulge in the blood vessel wall in your brain) or a brain tumour, which is an abnormal growth of tissue in the brain. Studying the flow of blood to the tumour can help to determine whether it's growing, which can be useful when planning treatment.

Heart

A coronary angiography is used to study the blood vessels that supply the heart. It may be used if you have any of the following conditions:

• heart attack – a serious medical emergency where the supply of blood to the heart is suddenly blocked, usually by a blood clot
• angina – chest pain that occurs when the blood supply to the heart is restricted
• heart disease – your heart's blood supply is blocked or interrupted by a build-up of fatty substances in the coronary arteries (the blood vessels that supply the heart)

A coronary angiography may also be used if you have a heart condition. It helps to determine the most appropriate type of treatment for you. This might be:

• a coronary angioplasty – a surgical procedure to widen blocked or narrowed coronary arteries
• coronary artery bypass graft – a surgical procedure to divert blood around narrow or clogged arteries in order to improve the blood flow to the heart
• aortic valve replacement – surgery to treat problems that affect the aortic valve, which is the valve that controls the flow of blood out of the left ventricle of the heart to the body’s main artery, the aorta)

See coronary angiography for more information about the procedure.

Lungs

A pulmonary angiography can be used to examine the blood vessels in the lungs. It's usually done when a person has a blood clot in one of the blood vessels in their lungs. This is known as a pulmonary embolism.

Performing a traditional catheter angiography carries a high risk of complications. Therefore, another type of angiography, known as a computerised tomography pulmonary angiography (CTPA), is usually the preferred option.

A CTPA involves injecting contrast dye into the blood vessels of your lungs before taking a CT scan. If you have a pulmonary embolism in one of your lungs, it will show up on the CT scan as a gap in your blood supply.

Arms and legs

An extremity angiography can be used to examine the blood vessels in your arms and legs. This procedure is often 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.

An extremity angiogram can also be used to check for narrowing and hardening of the arteries (atherosclerosis, see below) in the arms and legs.

Kidneys

Renal angiography can be used to examine the blood vessels in your kidneys. It may be recommended if you have symptoms which suggest that 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)
• symptoms of kidney disease, such as itchy skin and blood in your urine

Atherosclerosis

Atherosclerosis is a condition in which one or more of the arteries becomes narrowed and hardened due to a build-up of fatty materials, such as cholesterol. These types of material are collectively known as plaques.

Atherosclerosis is potentially dangerous because it can lead to organ failure and tissue death (gangrene).

Atherosclerosis doesn't usually cause any noticeable symptoms, so the most effective method for early diagnosis is to identify people who are in high-risk groups and test them for the condition. High-risk groups for atherosclerosis include people who:

• are over 40 years old
• are overweight or obese
• smoke or have a previous history of heavy smoking
• have a high-fat diet

An angiography is usually only carried out if initial tests, such as blood cholesterol tests and blood pressure tests, suggest that atherosclerosis is likely.

Read more about how atherosclerosis is diagnosed.

Other uses

An 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

Aneurysms

An aneurysm is a blood-filled sac that forms in a weakened part of a blood vessel.

Arteries

Arteries are blood vessels that carry blood from the heart to the rest of the body.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood vessels

Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Brain

The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.

Heart

The heart is a muscular organ that pumps blood around the body.

Kidneys

Kidneys are a pair of bean-shaped organs located at the back of the abdomen, which remove waste and extra fluid from the blood and pass them out of the body as urine.

Liver

The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.

Lungs

Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

X-ray

An X-ray is a painless way of producing pictures of inside the body using radiation.

If you have problems with your circulation, your GP may recommend an angiography to find out what's causing the problem. The results will help decide what the treatment options are.

As blood vessels supply blood to every part of your body, any part can be affected by circulation problems. The major internal organs (your heart, brain and kidneys) and the extremities (your arms and legs) are affected if the blood supply to them is changed by blockages or arterial disease (disease of the arteries).

Problems caused by serious arterial disease include:

• strokes
• heart attacks
• gangrene (tissue death)
• organ failure

Therefore, problems with your circulation should be investigated as soon as possible. The condition of your arteries can be assessed, and appropriate treatment options suggested.

Arteries

Arteries are blood vessels that carry blood from the heart to the rest of the body.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Brain

The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.

Heart

The heart is a muscular organ that pumps blood around the body.

Heart attacks

A heart attack happens when there is a blockage in one of the arteries in the heart.

Tissue

Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection or storing fat.  

Veins

Veins are blood vessels that carry blood from the rest of the body back to the heart.

Depending on the complexity of the investigation, an angiography takes between 20 and 90 minutes. You will usually be allowed to go home on the same day, although in some cases you may need to stay in hospital overnight.

An angiography is usually a planned procedure. However, it may occasionally be done on an emergency basis – for example, in the case of a heart attack.

In cases where an angiography is planned, you're likely to have an initial appointment to discuss a number of issues. As part of these discussions, 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 shortly before having an angiography. These may include:

• blood pressure tests
• blood tests to check how well organs, such as your kidneys or liver, are working
• pulse check (to see how quickly your heart is beating)

Before having an angiogram, some people prefer to take a sedative to help them relax. In this case, you will be asked not to eat for several hours before having the procedure. Your care team will be able to give you a precise recommendation.

The procedure

Most angiography procedures are carried out using local anaesthetic to numb the area of skin where the catheter (see below) is going to be inserted.

However, general anaesthetic (where you're asleep) is sometimes used when young children need to have the procedure. This is because it may be upsetting for them or they may find it too difficult to stay still during the procedure.

An angiography is usually carried out under the supervision of a radiologist (a doctor who specialises in using imaging studies). A nurse may also be present to assist with the procedure.

After making a small cut, 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 also be placed on your chest to measure your heartbeat. A blood pressure monitor may be attached to your arm.

A catheter is then inserted into one of your arteries. A catheter is a thin, flexible tube that's similar in size to a piece of spaghetti. Depending on the area of your body being examined, the catheter may be inserted into an artery in either your groin or your leg.

The radiologist will use X-rays or, in some cases, a CT or MRI scanner, to help guide the catheter to the area being examined. Contrast dye will then be injected through the catheter, and a series of X-rays will be taken.

The procedure isn't painful but you may feel a slight sensation of warmth 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 out during an angiography, 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 an angioplasty.

Once the procedure has been completed, the catheter will be removed and the incision will be closed using manual pressure, a plug or a clamp.

Afterwards

Following an angiography, you will usually be taken to a recovery ward. You will be asked to lie still for a few hours to prevent bleeding at the site of the incision. You may also be given an anticoagulant, which is a type of medication that can help to prevent bleeding.

After having an angiography, most people are able to leave hospital on the same day. However, you may occasionally need to stay in overnight for observation. You'll be able to eat and drink as soon as you feel ready to. It may take eight to 12 hours before you're well enough to resume normal activities.

Depending on what the radiologist finds during your angiography, they may be able to discuss your results with you shortly after the procedure. Alternatively, they may compile a report and send it to your GP.

Anaesthetic

Anaesthetic is a drug used to either numb a part of the body (local), or to put a patient to sleep (general) during surgery.

Arteries

Arteries are blood vessels that carry blood from the heart to the rest of the body.

Blood

Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Blood vessels

Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.

Catheter

A catheter is a thin, hollow tube usually made of rubber that is placed into the bladder to inject or remove fluid.

Heart

The heart is a muscular organ that pumps blood around the body.

Local anaesthetic

A local anaesthetic is a drug that is injected by needle or applied as a cream, which causes a loss of feeling in a specific area of the body.

Retina

The retina is the nerve tissue lining the back of the eye, which senses light and colour and sends it to the brain as electrical impulses.

Vein

Veins are blood vessels that carry blood from the rest of the body back to the heart.

X-ray

An X-ray is a painless way of producing pictures of inside the body using radiation.

Minor complications that can occur following an angiography procedure include:

• excessive bleeding at the site of the incision
• infection at the incision site, which may need to be treated with antibiotics
• a mid to moderate allergic reaction to the contrast dye; this can usually be controlled using anti-allergy medication

More serious complications can include:

• blood clots
• kidney damage
• stroke
• blood vessel damage
• a serious, life-threatening allergic reaction (anaphylaxis) to the contrast dye

These serious complications are very rare. For example, only an estimated 1 in 1,000 people will have a stroke as a result of having an angiography; approximately 1 in 50,000 to 150,000 people will experience anaphylaxis.

In almost every case, the benefit of having an angiography far outweighs any potential risk.