Right heart catheterisation: what it is, how it is done and the risks

Right heart catheterisation, often shortened to RHC, is a procedure used to study the right side of the heart and the blood vessels of the lungs. The Pulmonary Hypertension Association UK (PHA UK) explains that a small tube (catheter) is passed into a vein and guided around the body to take measurements in the heart and lungs.

The NHS describes the test as a thin, flexible tube inserted into a vein in the neck, arm or groin and passed through to the pulmonary artery, in order to confirm a diagnosis by accurately measuring the blood pressure in the right side of the heart and the pulmonary arteries.

PHA UK says it is the most accurate way to measure the blood pressure in your heart and in the blood vessels of your lungs, and that along with other tests it helps your doctor tell whether you have pulmonary hypertension or whether your symptoms are caused by something else. It may also help guide the best treatment.

The NHS says pulmonary hypertension can be difficult to diagnose because the symptoms, such as breathlessness and tiredness, are similar to those of other heart or lung conditions. It lists an echocardiogram, which estimates pressure in the pulmonary arteries, and right heart catheterisation as the 2 main tests used to help diagnose it, with several other tests used alongside them.

PHA UK also explains that if a right heart catheter is not done, the doctor will not have all the information they might need and will need to make the best decision with what is available, which increases the risk of receiving treatment that might not help.

A doctor will talk to you beforehand, answer your questions and ask you to sign a consent form. PHA UK says no fasting is required and you should take medicines as normal unless instructed otherwise by your doctor. Wear loose comfortable clothing and shoes.

Your team may tell you to stop certain medicines around the time of the procedure, most often blood thinners such as warfarin, rivaroxaban or apixaban, with specific instructions about restarting them. Tell staff about any allergies or sensitivities to medicines or latex, and about back or breathing problems that could make lying flat difficult.

The charity recommends bringing a family member or friend who can accompany you home and says it is generally recommended that you do not drive home afterwards if possible, since you may be tired and a little sore for the evening.

You change into a hospital gown and are taken to the catheterisation laboratory, where you lie fairly flat on a table that X-rays can be taken through. PHA UK says an entry point, usually at the neck or upper thigh, is cleaned, possibly shaved, and numbed with local anaesthetic. You should not experience much discomfort apart from the initial sting.

The doctor makes an opening in the vein and threads a long, thin, flexible catheter through the heart into the blood vessels in the lungs, using an X-ray machine to monitor its position. The catheter is used to measure the pressure in the heart chambers and the lung vessels, record oxygen levels in the blood, and work out how much blood the heart is pumping each minute.

Sometimes extra steps are included. PHA UK describes a vasodilator challenge, where a short-acting medicine, often breathed in through a mask, is given to see whether lung pressure falls, a fluid challenge to see how the heart copes with extra fluid, and in some cases exercise on a special bike during the test. When the measurements are complete the catheter is removed and pressure is applied to the site to prevent bleeding.

You are taken to a recovery room and seen by a doctor, who can give preliminary results and, if appropriate, new medicines before you go home. PHA UK advises avoiding heavy lifting for 24 hours, supporting the puncture site when coughing, sneezing or bending, and resting for the day.

If you have swelling, increased pain or bleeding after you leave, apply direct pressure to the site and seek help from your local doctor or an emergency department. The doctor will advise when you can return to normal activities or work.

PHA UK says most people have RHC without problems, but lists the following risks, with the frequencies quoted by the charity.