Coronary angiography and stenting: what happens, when it is needed and aftercare

What is coronary angiography?

Coronary angiography is an X-ray test in which a contrast dye is injected into the coronary arteries. The dye shows the inside of the vessels on screen so that any narrowing or blockage is clearly visible. It remains the reference test for assessing coronary heart disease.

It is carried out by an interventional cardiologist in a catheter laboratory (cath lab). Through a small puncture in an artery at the wrist (radial approach) or the groin (femoral approach), a thin flexible tube – a catheter – is guided up to the heart under X-ray.

Some people are offered a CT coronary angiogram first. This non-invasive scan, covered in our guide to MRI and CT scans, is useful for ruling out significant disease in people at moderate risk.

When is angiography needed?

The main reasons are:

• an acute heart attack – for ST-elevation heart attacks, angiography with stenting is done as an emergency, as quickly as possible;
• a non-ST-elevation heart attack or unstable angina – usually within hours to a day or two, depending on risk;
• stable angina when symptoms continue despite medicines or non-invasive tests suggest high risk;
• before heart valve surgery or other heart operations in people of a certain age or with risk factors;
• unexplained heart failure or serious rhythm disturbances.

A cardiologist decides whether the test is needed after a consultation, ECG, echocardiogram and often an exercise test or another functional test.

Angioplasty and stenting: what happens

If angiography shows a significant narrowing, the cardiologist can often carry out a percutaneous coronary intervention (PCI) straight away:

1. a very fine guidewire is passed across the narrowing;
2. a balloon is slid along the wire and inflated to widen the artery (angioplasty);
3. a stent – a mesh tube mounted on the balloon – is expanded and pressed into the artery wall to keep it open;
4. the balloon and catheters are removed, and the stent stays permanently.

Almost all stents used today are drug-eluting stents, which slowly release a medicine that lowers the chance of the artery narrowing again (restenosis). For complex narrowings the cardiologist may use intravascular ultrasound (IVUS), optical coherence tomography (OCT) or a pressure-wire measurement (FFR) to check whether the narrowing truly limits blood flow and whether the stent is well expanded.

Getting ready for the procedure

Before a planned angiogram you will usually:

• have blood tests, including kidney function, because the dye leaves the body through the kidneys;
• be asked not to eat for a few hours beforehand – follow the hospital's instructions;
• need to tell the team if you are allergic to contrast dye or iodine, have diabetes (especially if you take metformin), kidney disease or take blood thinners;
• sign a consent form after the doctor has explained the benefits and risks.

Do not stop or change your medicines unless told to. Some, such as anticoagulants, may be paused; others should be continued.

What the procedure feels like

You stay awake and receive a local anaesthetic at the puncture site, sometimes with a mild sedative. Angiography alone usually takes 20–40 minutes; adding a stent takes longer depending on complexity.

You may feel a brief warm flush when the dye is injected. Some people notice mild chest discomfort while the balloon is inflated – tell the team what you are feeling.

With the wrist approach, a tight band is placed around the wrist for a few hours and you can usually sit up and walk soon afterwards. With the groin approach you need to lie flat for a few hours. After a planned procedure many people go home the same day or the next day; after a heart attack the stay is longer.

Risks and complications

Angiography and stenting are routine, and serious complications are uncommon, but you should know about them:

• bruising, a lump (haematoma) or bleeding at the puncture site – the most common problem and usually harmless;
• an allergic reaction to the contrast dye;
• a temporary dip in kidney function, more likely in people with kidney disease or diabetes;
• heart rhythm disturbances during the procedure;
• rarely, damage to an artery, a heart attack, stroke or the need for emergency surgery;
• stent thrombosis – sudden blockage of the stent, rare but serious; the risk is highest if antiplatelet medicines are stopped too early.

Emergency procedures for a heart attack carry higher risks, but the benefit of reopening the artery far outweighs them.

Living with a stent

After a stent you will usually be prescribed dual antiplatelet therapy – aspirin plus a second antiplatelet medicine – for a period that typically ranges from one to twelve months, depending on your situation and bleeding risk. After that, one antiplatelet medicine is usually continued long term. Never stop these medicines yourself, even before dental work or another operation – speak to your cardiologist first.

A stent fixes one particular narrowing but does not treat atherosclerosis elsewhere. So it is important to:

• take your statin and other prescribed medicines;
• stop smoking;
• keep an eye on blood pressure, cholesterol and blood sugar;
• eat well – see heart-healthy eating;
• attend cardiac rehabilitation and stay physically active.

You will not feel the stent, it does not move, and modern stents do not prevent MRI scans – but always carry your stent card. If angina returns on exertion, contact your cardiologist.

When to see a doctor, and treatment abroad

Seek urgent help or call 112 if after the procedure you have severe chest pain, breathlessness, rapidly increasing swelling or bleeding at the puncture site, or a cold or numb hand or leg. Book a routine appointment if angina appears on exertion, you have palpitations, or you are unsure about continuing your medicines.

If you have been advised to have complex stenting, or are unsure whether a stent or bypass surgery is best, a second opinion can be helpful. Some patients from across Europe choose large accredited hospital groups in Istanbul; if you do, check the hospital's accreditation and the interventional cardiologist's experience, ask for a written treatment plan and arrange follow-up at home. New City Clinic in Istanbul coordinates hospital, doctor, hotel, transfers and an interpreter, while all medical decisions stay with the cardiologists.