Coronary Angiography

Coronary angiography is an X-ray imaging test that lets doctors see the inside of the arteries that supply blood to the heart muscle.

During the test, a thin flexible tube called a catheter is guided through a blood vessel in the wrist or groin and advanced toward the heart. A contrast dye (a liquid visible on X-ray) is then injected through the catheter directly into the coronary arteries (the blood vessels that feed the heart). A live X-ray camera records how the dye flows, revealing any areas where the arteries have narrowed or become blocked. This real-time picture helps the cardiologist (heart specialist) understand exactly where a problem is and how serious it is.

Coronary angiography is ordered when a doctor needs a clear, detailed map of the heart's blood supply — usually because symptoms or earlier tests suggest there may be a blockage or narrowing in the coronary arteries.

• Chest pain (angina) that has not been fully explained by non-invasive tests such as a stress test or CT angiography
• A heart attack (myocardial infarction — when part of the heart muscle is damaged by a blocked artery), either recent or suspected
• Abnormal results on a stress test or nuclear imaging scan of the heart
• Heart failure (when the heart cannot pump enough blood for the body's needs) thought to be caused by blocked arteries
• Before heart surgery, to check whether the coronary arteries also need to be treated
• Certain types of arrhythmia (irregular heartbeat) that may be linked to reduced blood flow to the heart
• Follow-up after a previous procedure to open or bypass a blocked artery, if new symptoms develop

Coronary angiography is usually avoided, or the timing is adjusted, in some situations. Your cardiologist will weigh the benefits and risks carefully.

• Severe kidney disease (impaired kidneys may struggle to clear the contrast dye)
• Allergy to contrast dye — pre-treatment with medicines is usually possible but must be discussed in advance
• Blood-clotting disorders that make bleeding harder to control
• Active infection or uncontrolled severe illness
• Pregnancy, unless the situation is urgent, because of radiation exposure to the baby

Coronary angiography is a well-established diagnostic procedure and is considered low risk for most patients, but like any procedure involving a catheter inside the body and contrast dye, it carries some recognised risks.

• Bruising, swelling, or a small lump of blood (haematoma) at the catheter entry site in the wrist or groin — the most common side effect
• Allergic reaction to the contrast dye, ranging from a mild skin rash to, rarely, a more serious reaction
• Temporary worsening of kidney function due to the contrast dye, particularly in patients who already have kidney problems
• A small risk of bleeding from the blood vessel where the catheter was inserted
• Heart rhythm disturbances (arrhythmia) triggered during the procedure, which usually resolve quickly
• Rarely, damage to the wall of an artery (dissection) as the catheter is guided through
• Very rarely, a stroke or heart attack caused by a blood clot dislodged during the procedure
• Very rarely, an air bubble (air embolism) entering the bloodstream

Good preparation helps the procedure go smoothly and reduces risks. The steps below reflect what most hospitals require, but your care team will give you instructions specific to your situation.

Before the procedure, patients are usually asked to fast — meaning nothing to eat or drink (except small sips of water for essential tablets) — for several hours beforehand. The exact fasting window is set by your team. Blood thinners, diabetes medicines, and some blood-pressure medicines may be paused or adjusted before the test; your doctor will advise on this. Smoking should be avoided in the days leading up to the procedure, as it affects blood vessels and wound healing. Alcohol is also best avoided for at least a day before.

Several tests are commonly done before the procedure to make sure it is safe:

• Blood tests — to check kidney function, blood-clotting ability, and general health
• An ECG (electrocardiogram — a recording of the heart's electrical activity) to get a baseline picture of heart rhythm
• A chest X-ray in some cases
• An echocardiogram (ultrasound scan of the heart) if not already done recently
• A review of any known allergy, especially to contrast dye or iodine

On the day of the procedure, here is what typically happens, step by step:

• You change into a hospital gown and a nurse checks your blood pressure, pulse, and temperature.
• A small needle (cannula) is placed in a vein in your arm so medicines can be given if needed.
• You lie on a padded table in the catheterisation laboratory (cath lab — a special room with X-ray equipment).
• The entry site — usually the wrist (radial artery) or groin (femoral artery) — is cleaned and numbed with a local anaesthetic (numbing medicine injected under the skin), so most patients feel pressure but not sharp pain.
• A thin introducer sheath (a small hollow tube) is placed into the artery to act as a guide port.
• The catheter is threaded gently through the sheath and guided up toward the heart using X-ray images on a monitor.
• When the catheter tip is positioned at the opening of a coronary artery, the contrast dye is injected and X-ray images are recorded from several angles.
• The process is repeated for each coronary artery that needs to be examined.
• Once imaging is complete, the catheter and sheath are removed. Pressure is applied to the entry site to stop any bleeding, and a dressing or a small wristband device is used to keep firm pressure on the wound.
• You are moved to a recovery area for monitoring. The total time in the cath lab is usually under an hour, though this can vary.

After the procedure, you will be monitored closely for a period of time — usually several hours — to make sure the entry site is not bleeding and your heart rhythm and blood pressure are stable. Many patients go home the same day, while others stay overnight depending on their overall condition and what the angiography revealed. Your care team will tell you which applies to you.

• Keep the entry site clean and dry for the first day or two; your nurse will explain how to care for the dressing or wristband device and when it can be removed.
• Watch for signs of a problem at the entry site: increasing swelling, a growing lump, heavy bleeding, or numbness in the hand or leg — and contact your care team immediately if any of these occur.
• Drink plenty of water in the hours after the procedure to help your kidneys flush out the contrast dye, unless your doctor has restricted fluids.
• Rest for the remainder of the day; most hospitals advise avoiding heavy lifting and strenuous activity for at least a day or two, especially if the groin was used.
• Blood thinners or other medicines may be prescribed or adjusted based on the angiography findings.
• Driving is usually not allowed on the day of the procedure; check with your team about when it is safe to drive again.
• A follow-up appointment will be arranged so your cardiologist can explain the results in detail and discuss the next steps — which may include medical treatment, a procedure to open a narrowed artery (angioplasty), or heart bypass surgery, depending on what was found.
• If you experience chest pain, shortness of breath, or feel unwell after going home, seek medical attention promptly.