If you have circulation problems, your GP may recommend that you have an angiogram to find out what's causing the problem. The results of an angiogram 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 angiogram, 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
A similar procedure that's used to study the blood vessels in your head and neck is called a cerebral angiogram.
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 angiogram 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 angiogram 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.
Coronary angiography is used to study the blood vessels that supply the heart muscle. 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
- coronary heart disease – your heart muscle'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 angiogram 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 and stenting – a 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 muscle
- 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
A pulmonary angiogram 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 angiogram 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 blockage in your blood supply.
Arms and legs
An extremity angiogram 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.
Renal angiograms 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 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). Plaques may also rupture causing events such as a heart attack or stroke.
During its early stage, 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
- have uncontrolled high blood pressure
- are diabetic
- have high cholesterol
- have a family history of cardiovascular disease
- are from south Asian ethnic decent
An angiogram is usually only carried out if initial tests, such as blood cholesterol tests and blood pressure tests, suggest that atherosclerosis is likely and symptoms have developed.
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