Cardiac catheterisation

Cardiac catheterisation, also known as an angiogram or coronary angiography, is a minimally invasive procedure where a flexible, long, thin tube (catheter) is inserted into an artery (a blood vessel carrying oxygen-rich blood) via a small cut in your arm or groin.

The catheter is guided to your heart using X-ray imaging. Once the blood vessels supplying your heart (coronary arteries) are reached, a special dye called a contrast agent is injected via the catheter. This allows your coronary arteries to be clearly imaged via X-ray.

Reasons for having a cardiac catheterisation

Cardiac catheterisation is recommended if you have had a heart attack to assess the damage caused or if you have symptoms that suggest a problem with your heart. These symptoms include: 

• Breathlessness
• Chest pain
• Pain in your arm, jaw or neck that cannot be explained by other causes

It may also be recommended if you have an electrocardiogram (ECG) that shows abnormal results.

Cardiac catheterisation can check how well your heart is working by measuring the pressures within your heart using pressure sensors on the catheter.

Cardiac catheterisation can, therefore, be used to help diagnose a range of suspected conditions affecting the heart. This includes:

• Angina
• Coronary artery disease
• Heart failure
• Heart valve disease
• Pulmonary hypertension
• Small vessel disease

If a blocked or narrowed coronary artery has been identified via other imaging tests or during cardiac catheterisation, treatment can be performed to widen the coronary artery (coronary angioplasty). Cardiac catheterisation can, therefore, be used both as a diagnostic test and a means to carry out treatment. 

Is an angiogram right for you?

An angiogram or cardiac catheterisation may not be possible if you have a severe allergy to the contrast agent or if you have poor kidney function, for example, due to kidney disease. This is because the contrast agent can strain your kidneys.

An angiogram may also be delayed if you have an active infection. This is because there is a small risk that the procedure could spread the infection. Once the infection has cleared, your angiogram can be scheduled again.

Similarly, if you have serious health conditions that are not well-controlled, such as diabetes, heart failure, respiratory failure and bleeding disorders, your angiogram may need to be delayed until these conditions are stable.

Cardiac catheterisation is also not recommended if you are pregnant due to the use of radiation in the form of X-rays and the potential effects this could have on a foetus.

A local anaesthetic is applied to numb an area on your arm or groin where a small cut is made. A guidewire is inserted into an artery through this cut, followed by a catheter. The catheter containing the guidewire is carefully guided to your heart using X-ray fluoroscopy.

X-ray fluoroscopy refers to a type of continuous X-ray. During an angiogram, this allows live images of your blood vessels to be displayed on a screen so that your doctor can effectively guide the catheter to your coronary arteries.

Once the catheter reaches your coronary arteries, a contrast agent is injected via the catheter. Detailed images of your coronary arteries can then be captured via X-ray fluoroscopy.

Once your angiogram is complete, the catheter is carefully removed, and pressure is applied to the wound site to stop the bleeding. A dressing will be applied before you leave hospital.

Before your procedure 

You will have an appointment with a healthcare professional to discuss your symptoms and medical history and answer any questions you may have.

You will be told what to expect during the procedure, its risks and benefits, and you can discuss whether you would like to have a sedative during your procedure. The sedative given during cardiac catheterisation will not put you to sleep, but will make you feel relaxed and drowsy. This is called conscious sedation.

Your care team will also let you know whether you need to temporarily stop taking certain medications before your cardiac catheterisation and for how long — you should not stop taking medication unless specifically advised to do so by your care team.

They will additionally let you know whether you need to have any other tests before your procedure, such as blood tests or scans.

If you decide to have a sedative on the day of your procedure, your care team will let you know how long you need to fast for in the run-up to your procedure. This means not eating or drinking anything other than water.

On the day of your cardiac catheterisation, you will be asked to remove all clothing from the waist up and will be given a hospital gown to change into. You should make sure you also remove any metal items from the waist up as metal can interfere with the imaging process.

Who will be involved?

Your cardiac catheterisation will be performed by a highly skilled specialist consultant called an interventional cardiologist. They will be supported by an experienced nurse and radiology technician.

How long does cardiac catheterisation take?

Cardiac catheterisation usually takes about 30 minutes. However, if it’s decided during your procedure that treatment should be performed at the same time (eg angioplasty), the procedure can take longer, up to 2 hours.

Anaesthetic choices

Cardiac catheterisation in adults is performed under a local anaesthetic to numb the area in your arm or groin where the cut is made to insert the catheter. As there are no pain sensors inside your arteries, you will not feel any pain as the catheter is moved through your arteries.

If you are feeling anxious about your procedure, you can have a mild to moderate sedative in addition to a local anaesthetic.

Pain during and after your procedure

The use of a local anaesthetic means you will not feel any pain during your procedure. However, your wound site may feel tender for up to a week, and you may notice some bruising there for up to 2 weeks.

You will be prescribed over-the-counter painkillers to help manage any pain around your wound site.

What happens straight after your procedure?

As soon as your procedure is complete, the catheter will be carefully guided out of your body.

If the catheter was inserted via a cut in your groin, it will be closed using a special stitch, surgical plug or other sealing device, or pressure will be applied for 10–20 minutes. You will be asked to lie flat until any bleeding has stopped. After 2–3 hours, you will be able to sit up and then walk around.

If the catheter was inserted via a cut in your arm, a pressurised cuff will be placed around the wound, and the pressure will be gradually reduced over 2–3 hours. You will be able to sit up and walk around soon after the cuff is in place.

Your pulse and blood pressure will be checked, and a dressing will be placed over your wound site before you go home. If you have a sedative, you must have someone accompany you home. If you do not have a sedative, it is still recommended that you have someone take you home as you may feel tired.

You may feel tired after your procedure, but you should feel back to normal after 24 hours. It’s a good idea to have someone stay with you overnight in case you feel unwell.

Your wound site will feel tender for up to a week, and any bruising may take up to 2 weeks to disappear. You can take over-the-counter painkillers, as instructed by your care team, to ease any discomfort.

In the first few days after your cardiac catheterisation, avoid any strenuous activity, particularly heavy lifting, and keep your wound site dry by having showers instead of baths. If you have a plaster over the wound site in your groin, it can be removed after 24 hours and doesn’t usually need replacing.

Follow your care team’s instructions regarding when to return to driving. In most cases, you should not return to driving until 3 days after your procedure.

You can usually return to most of your usual activities, including work, after 3 days.

Cardiac catheterisation is generally considered to be a safe procedure with a low risk of complications. However, complications that may occur include:

• Allergic reaction to the contrast agent — this is rare and usually mild; you will be monitored during and after your procedure and treated immediately if needed
• Bruising — this often occurs around the wound site and disappears within 2 weeks
• Haematoma — a small collection of blood under the wound site that usually goes away on its own after a few days

In very rare cases, the artery that the catheter was initially passed through may be damaged; you may have a stroke or heart attack, your kidneys may be damaged by the contrast agent, or you may develop an infection around the wound site. These rare complications occur in fewer than 1,000 cases.

Signs of infection around the wound site include redness, swelling, yellow or green-tinged discharge and the skin feeling unusually warm to the touch. If you notice any of these signs, you should contact your care team immediately. 

If cardiac catheterisation is not suitable in your circumstances, your doctor may recommend non-invasive tests. These tests cannot provide the same information as cardiac catheterisation, but they may be able to provide enough information to reach a diagnosis. These tests include:

• CT coronary angiography — a CT scan of your heart’s blood vessels that involves the use of a contrast agent, but without needing a catheter to be passed through to your heart
• Echocardiography — an ultrasound scan of your heart to capture real-time images of your heart beating, which can investigate heart muscle, heart valve and blood flow problems
• Stress testing — an electrocardiogram to measure your heart’s electrical activity while you are exercising (eg on a treadmill or exercise bike)