What Happens During a Coronary Angiogram? A Step-by-Step Patient Guide
Learn why a coronary angiogram is performed, what happens through the wrist or groin, what the results mean, the risks and how recovery works.
By Dr Heeraj Bulluck, MBBS, PhD, FRCP, FESC
A coronary angiogram is a procedure that shows the arteries supplying blood to the heart muscle. It can identify narrowing or blockage and help your cardiologist decide whether treatment should involve medicines, a stent or bypass surgery.
Many people feel anxious because the test involves the heart and an artery. Understanding each stage usually makes the experience less intimidating.
What is a coronary angiogram?
The coronary arteries cannot be seen clearly on an ordinary X-ray. During an angiogram, a thin flexible tube called a catheter is passed through an artery in the wrist or groin towards the heart. Contrast dye is injected through the catheter while X-ray images are taken.
The moving images show how contrast travels through the coronary arteries and whether blood flow is being restricted.
A coronary angiogram is also called invasive coronary angiography or cardiac catheterisation. It is different from a CT coronary angiogram, which uses a CT scanner and contrast injected into a vein rather than a catheter placed in an artery.
Why might I need one?
An angiogram may be recommended to:
- investigate angina or other symptoms suggesting reduced blood flow to the heart
- assess a heart attack or unstable angina
- clarify an abnormal or inconclusive non-invasive test
- define coronary anatomy before a planned treatment or operation
- assess previously treated coronary disease in selected cases
- measure pressures or obtain other information about the heart during catheterisation
The test should answer a specific clinical question. Ask what your cardiologist hopes to learn and how the result could change your treatment.
How should I prepare?
Your hospital will provide instructions covering food, drinks, arrival time and medicines. Follow those instructions rather than general advice online.
Tell the team if you:
- take anticoagulant, antiplatelet or diabetes medication
- have kidney disease
- have previously reacted to contrast dye
- have an allergy or severe asthma
- may be pregnant
- have an infection or feel unwell
- need help with mobility, communication or anxiety
Do not stop prescribed medication unless the hospital specifically instructs you to do so.
Blood tests may be arranged to check kidney function, blood count and clotting. An ECG and other observations may also be taken.
What happens when I arrive?
A nurse or doctor will confirm your details, medicines, allergies and consent. You will have an opportunity to ask questions.
The cardiologist will discuss the reason for the angiogram, expected benefits, alternatives and material risks. The access site, usually the wrist or groin, will be examined and prepared.
You may be offered a sedative to help you relax, but many angiograms are performed with the patient awake. The access area is numbed with local anaesthetic.
What happens during the angiogram?
You lie on an X-ray table in the cardiac catheter laboratory. ECG stickers monitor the heart rhythm, and blood pressure and oxygen levels are checked.
1. The artery is accessed
After local anaesthetic, a short tube called a sheath is placed into an artery, most commonly at the wrist. A groin artery may be used when this is more suitable.
You may feel pressure or movement, but you should not feel sharp pain. Tell the team if you are uncomfortable.
2. The catheter is guided towards the heart
The cardiologist passes fine catheters through the artery under X-ray guidance. Blood vessels do not have the same pain sensation as skin, so most people do not feel the catheter travelling inside them.
3. Contrast is injected
Contrast dye is injected into the coronary arteries while short X-ray sequences are recorded from different angles. Some people notice a brief warm sensation. Tell the team immediately if you feel itching, tightness in the throat, breathing difficulty, chest pain or anything unexpected.
4. Additional measurements may be taken
If a narrowing is uncertain, the cardiologist may use pressure wires or imaging inside the artery to determine whether it is significant and how best to treat it.
5. The catheter is removed
At the end, the catheter and sheath are removed. Pressure is applied to prevent bleeding. A compression band is commonly used at the wrist; the groin may require pressure or a closure device.
The duration varies with the clinical situation and whether extra measurements or treatment are required.
Is an angiogram the same as an angioplasty?
No. An angiogram is primarily a diagnostic test. Angioplasty, also called PCI, is treatment that uses a balloon and usually a stent to widen a coronary narrowing.
In some situations, angioplasty is performed immediately after the angiogram. In others, the team discusses the result with you first or refers you for bypass surgery or medical treatment. Before the procedure, ask whether immediate angioplasty is a possibility and what consent has been agreed.
What might the angiogram show?
The result may show:
- no important obstructive coronary disease
- mild or moderate plaque best managed with medicines and risk-factor treatment
- one or more severe narrowings suitable for a stent
- a pattern where bypass surgery should be considered
- a narrowing that needs further pressure or imaging assessment
A non-obstructive angiogram does not mean the symptoms were imagined. Some people have microvascular angina, coronary spasm or a non-cardiac cause requiring further assessment.
What happens afterwards?
You return to a recovery area where staff monitor your pulse, blood pressure and access site. Wrist procedures often allow earlier mobilisation. A groin procedure may require a period lying flat.
Many planned angiogram patients go home the same day. You will need discharge instructions and may need someone to accompany you, particularly if sedation was used.
Mild tenderness and bruising at the wrist or groin are common. Follow the hospital's advice on wound care, bathing, lifting, work, driving and exercise because restrictions vary with the access site, sedation, findings and whether angioplasty was also performed.
What are the risks?
Coronary angiography is commonly performed and serious complications are uncommon. Possible risks include:
- bruising, bleeding or a collection of blood at the access site
- damage or blockage involving the wrist or groin artery
- an allergic reaction to contrast
- temporary or, less commonly, significant kidney injury
- an abnormal heart rhythm
- damage to a coronary artery
- heart attack or stroke
- radiation exposure
- very rarely, emergency surgery or death
Personal risk is higher in some emergency procedures and in people with severe heart disease, kidney disease or other significant illness. Your cardiologist should explain the risks that apply to you rather than quoting only a general figure.
When should I seek help after going home?
Follow your discharge instructions. Seek urgent help for:
- bleeding that does not stop with firm pressure as instructed
- rapidly increasing swelling at the wrist or groin
- a cold, pale, painful or numb hand or leg
- severe or persistent chest pain
- marked breathlessness, collapse or symptoms of stroke
- a severe allergic reaction
Contact the treating unit for increasing redness, discharge, fever, worsening pain or uncertainty about the wound.
Questions worth asking
- Why is invasive angiography preferable to another test in my case?
- Will you use the wrist or groin?
- Could angioplasty be performed at the same sitting?
- How is my kidney function?
- Which medicines should I take or withhold?
- What did the angiogram show?
- Does a narrowing affect blood flow?
- Is the aim of treatment symptom relief, prevention, or both?
- What are my driving and activity restrictions?
The central message
A coronary angiogram gives detailed information about the arteries supplying the heart. Most people remain awake, the skin is numbed, and recovery is relatively short after an uncomplicated planned procedure.
The important outcome is not simply whether a “blockage” exists. It is understanding what the findings mean, how they explain your symptoms and what treatment is most likely to improve your health.
Medical note: Preparation, medicine instructions and recovery restrictions vary. Follow the instructions from the hospital performing your procedure.
Sources
Also published on Medium and LinkedIn.
Have questions about your heart health?
Dr Heeraj Bulluck offers thorough assessment and clear explanations at Beacon Hospital, Dublin.