Angiography vs Angioplasty: What Is the Difference?
Angiography shows whether your heart arteries are narrowed; angioplasty opens them. This side-by-side guide explains how each is done, why both often happen on the same day, whether every blockage needs a stent, and which questions to ask your cardiologist.
Dr Amol H. PatilMBBS, MD, DM (Cardiology) · 21 October 2026 · 5 min read
Short answer: coronary angiography is a test, and coronary angioplasty is a treatment. In angiography, a thin flexible tube (catheter) is guided to the heart's arteries, a dye is injected, and X-ray pictures show whether any artery is narrowed or blocked. In angioplasty, a similar catheter carries a tiny balloon to the narrowed part and opens it, and in most cases a stent, a small metal mesh tube, is left in place to keep it open. Angiography finds the problem; angioplasty treats it, when that is the right treatment for you.
Side-by-side comparison
| What you want to know | Coronary angiography | Coronary angioplasty |
|---|---|---|
| Purpose | To see the coronary arteries and find out whether, where and how badly they are narrowed. | To widen a narrowed or blocked coronary artery so that blood can flow through it again. |
| What is done | A catheter is passed from an artery in the wrist (radial) or groin (femoral) up to the heart. Dye is injected and an X-ray video is recorded. | Through a similar catheter, a fine wire is passed across the blockage. A balloon is inflated to open it, and usually a stent is placed. The stent stays in the artery permanently. |
| Anaesthesia | Local anaesthetic at the wrist or groin. You stay awake; a mild sedative is sometimes given. | Local anaesthetic, as for angiography. You stay awake; sedation is given if needed. |
| Typical time in hospital | Often a day-care test, with discharge the same day if all is well. This varies with your condition and the hospital. | After a planned angioplasty, often the next day. After a heart attack or a complex procedure, usually longer. Your cardiologist will advise. |
| What you get at the end | A report and recorded images (on CD or digitally) describing each artery, with a recommendation: medicines alone, angioplasty, or bypass surgery. | An opened artery, a procedure report with stent details, a list of medicines, including blood thinners to protect the stent, and a follow-up plan. |
For how each procedure is planned and done at this practice, see coronary angiography and coronary angioplasty (PTCA).
Why the two often happen on the same day
In a heart attack, there is no time to separate them. Angiography is done first to find the blocked artery, and angioplasty follows straight away on the same table. This is called primary angioplasty. What to do before you reach hospital is covered in heart attack: what to do in the first hour.
In planned cases too, angioplasty may follow angiography in the same sitting. This usually happens when the pictures show a blockage that clearly needs treatment and is suitable for a stent, and when you and your family have already discussed this possibility and given consent before the test. It avoids a second puncture and a second dose of dye.
Sometimes it is wiser to stop after angiography and decide later. Examples include narrowing in several arteries or in the left main artery, where bypass surgery may also be an option; reduced kidney function, where the total amount of dye matters; or a family that needs time to weigh the choices. Before you sign the consent form, ask which plan your cardiologist has in mind.
Does every blockage need a stent?
No. A narrowing that looks significant on angiography does not always reduce blood flow enough to matter, and a stent is not the only treatment.
- FFR (fractional flow reserve) uses a pressure wire passed across the narrowing to measure how much it actually limits blood flow. It helps decide whether a borderline blockage needs a stent.
- IVUS and OCT are imaging tools that look at the artery from the inside. They show the size of the vessel and the type of plaque, help choose the right stent size, and check that the stent has opened fully.
- Medicines and lifestyle changes, such as tablets for cholesterol, blood pressure and angina, stopping smoking and regular activity, may be enough for many people with stable angina.
- Bypass surgery may suit some people better, for example those with disease in several arteries or the left main artery, particularly if they have diabetes. Such decisions are often made together with a cardiac surgeon.
Read more about these tools on our intravascular imaging, OCT, IVUS and FFR page, and about the underlying disease on coronary artery disease and angina. High blood pressure is one of the main drivers of artery narrowing, and blood pressure numbers explained covers what your readings mean.
Questions to ask your cardiologist
- Why do I need this test now, and what will happen if a blockage is found?
- Will you go through the wrist or the groin, and why?
- If a blockage is found, will angioplasty be done in the same sitting, or will we decide together afterwards?
- Does the blockage actually limit blood flow? Will FFR or imaging such as IVUS or OCT be used?
- What are my options — medicines, a stent or bypass surgery — and why do you suggest this one for me?
- What are the risks in my case, especially if I have kidney disease, diabetes or a past reaction to dye?
- Do I need to stop or change any medicine, such as blood thinners or diabetes tablets, before the test?
- Which medicines will I need after a stent, and for how long? Never stop blood thinners without speaking to your cardiologist first.
- When can I return to work, drive and travel, and when is my next review?
- Will I get a copy of the images and the report?
Bring all your previous reports and any angiography CD when you book an appointment. They help the doctor compare and can avoid repeating tests.
Sources
For understanding only — the right test or treatment is decided after examination.
