What is a coronary angiogram?

Coronary Angiogram is a diagnostic procedure by which the blood vessels of your heart are visualized using X-rays. Done under local anaesthetic, a small catheter is advanced from the wrist or groin to your heart and a special “dye” (contrast media) is injected into the blood vessels that supply your heart muscle. Digital images and videos are recorded using special X-ray cameras.

Also known as Cardiac Catheterization or Coronary Angiography, this procedure was first performed by Dr Mason Sones in 1958 and is the Gold Standard by which the diagnosis of coronary artery disease is made.

These pictures and videos will allow the doctor to visualize what is going on inside your blood vessels. Depending on what is seen, they can perform procedures to open arteries that are partially or completely blocked. It can also determine how well the valves in between the chambers of your heart is working and how well the heart muscle is pumping.

Understanding the Heart artery anatomy

This heart is a muscular organ kept alive by millions of blood vessels supplying oxygen and nutrients to give it energy to keep pumping. The three main blood vessels that are of utmost importance are the Left Anterior Descending (LAD) artery, the Left Circumflex Artery (LCx) and the Right Coronary Artery (RCA). If the heart doesn’t get enough oxygen, chest pain or a heart attack can result.

Role of the 3 main coronary vessels

  • The LAD – supplies the front and left hand side of the heart
  • The LCX – supplies the left and sometimes the back of the heart
  • The RCA – supplies the right and bottom side of the heart

This test picks up blockages in your heart due to Atherosclerosis.

Atherosclerosis is the process by which fatty deposits narrow the coronary artery, depriving the heart muscles of oxygen and nutrients it needs to function well. Over time, this can weaken or damage the heart. If a plaque splits or breaks, the body tries to fix this by forming a blood clot around it. The new clot can block blood in the artery and stop blood flow to the heart. This is a common cause of a ‘heart attack’.

Who will benefit from this procedure?

This test is ordered by your physician when he suspects you have a heart problem.

  1. 1
    You have Angina Pectoris
  1. 2
    You have symptoms of Heart Failure or Valve Disorder
  1. 3
    Your cardiac test results are abnormal
  1. 4
    You have recurrent fainting episodes
  1. 5
    You have chest pains again after a previous coronary angioplasty
  1. 6
    You are suspected of having a heart attack

What are the benefits of this procedure?

The Coronary angiogram helps to highlight what your heart problem is and in many situations, help your cardiologist treat the problem, alleviate your symptoms, increase your longevity and reduce the risk of sudden death.

Unique advantages of this procedure

  • It is definitive and conclusive
  • The results are known immediately
  • Treatment with Coronary Angioplasty (stenting) can be done at the same sitting once the diagnosis of functionally significant coronary artery disease is confirmed.
  • Stops unnecessary further tests and medications

This procedure is used to:

  1. 1
    Diagnose the presence and severity of coronary artery disease
  1. 2
    Coronary Angiography helps to answer the following questions 
  • Is there any heart artery blockages?
  • How many blockages are there?
  • Where the blockages located?
  • How severe are the blockages?
  • What is the best way to treat it?
  1. 3
    Diagnose coronary artery anomalies

Coronary artery anomalies are congenital abnormalities in which the origin or course of the coronary artery is anatomically different. In some cases, they can cause severe reduction of blood flow to the heart muscles (myocardium) and lead to chest pain, irregular heart beats (arrhythmias) and sudden cardiac death.

  1. 4
    Assess aetiology and severity of heart failure

A specialized catheter shaped like a pigtail is advanced from your wrist into the left ventricle and dye is injected to opacify this chamber and assess the strength of its pumping function (contractility).

Video 1:

Left ventriculogram demonstrating normal contractility (Ejection fraction 60%)

Video 2:

Left ventriculogram demonstrating severe Heart Failure with poor contractility (Ejection fraction 15%) 

Video 1:

Apical hypertrophy cardiomyopathy is a congenital condition whereby there is abnormal thickening of the heart muscles at the apex of the left ventricle.

Video 2: 

Severe Mitral Regurgitation is a condition whereby the valve controlling blood flow between the left atrium and left ventricle is dysfunctional, allowing blood to flow in a backward instead of a forward direction. 

Are there any other less invasive tests for my condition?

There are other tests available to diagnose coronary artery disease and you may have already had some of them before your doctor decided that this test was clinically indicated for you.

These tests include:

  • Exercise stress ECG (Treadmill test)
  • Exercise stress echocardiogram (ESE)
  • Exercise stress myocardial perfusion imaging
  • Dobutamine stress myocardial perfusion imaging
  • Multi-slice CT coronary angiography (CTA)
  • Cardiac Positron Emission Tomography perfusion stress test (PET)

The common tests listed above provide different kinds of diagnostic information. However, the coronary angiogram is generally the most accurate way to confirm coronary artery disease.

Basic facts about this procedure

It is an OUTPATIENT procedure

On the morning of your procedure, you will be asked to come to the Day ward fasted from 12 midnight. A straightforward coronary angiogram procedure will only take 30-45mins

Normal Findings

Home after 4-6 hours stay in day ward

If stenting is done 

1 night's stay in ICU & 1 day's stay in the general ward (if necessary)

It is NOT an Operation

The procedure is done under local anaesthesia. Light sedation may be given to you if you are feeling anxious

Pain if any, is usually MINIMAL

The initial skin injection of the local anaesthetic can be slightly uncomfortable but subsequent insertion of the diagnostic catheters should cause no more than slight discomfort.

It is a SAFE procedure with minimal risks

Coronary Angiogram is a very common & well-tolerated diagnostic procedure performed > 2 million times per year worldwide with minimal risks.

The common risks (<5%) include bruising and bleeding at the puncture site. Rare risks (<1%) include allergic reaction to the contrast dye, impaired kidney function due to contrast dye, abnormal heart rhythm and infection. Extremely rare complications (0.1%) include heart attack, stroke, need for emergent cardiac surgery, and death.

How should I prepare for procedure?

Before the day of the procedure

  • The doctor will explain how the procedure is performed, the risks
    and benefits and expected duration of stay in the hospital.
  • Informed consent will be obtained.
  • Routine blood tests and ECG will be done before the procedure.
  • Inform the doctor of:
  • Any allergies (particularly allergies to iodine, X-ray contrast medium, and any pain-relieving medications)
  • Any history of peptic ulcer, recent strokes or bleeding tendencies
  • Any plans to go for surgery (eg cataract, knee, dental surgery)
  • Any history of impaired kidney function
  • Instructions for medications
  1. Metformin (Glucophage) – Stop taking it 2 days before the procedure
  2. Blood thinners should be stopped 2 days before the procedure at the advise of your doctor. These include:
  1. Warfarin (Coumadin; Marevan)
  2. Dabigatran (Pradaxa)
  3. Apixaban (Eliquis)
  4. Rivaroxaban (Xarelto)
  1. Continue Aspirin and/or Clopidogrel if prescribed by your doctor
  • Keep yourself well-hydrated. This will reduce the risk of kidney impairment due to the injection of the dye.

On the day of the procedure


  • Proceed to the admission office where the staff will settle you comfortably in your room.


  • You may drink water, consume a light breakfast (eg cereal/eggs/toast/milo) 4 hours before your procedure. Please keep nil by mouth thereafter. Food will be provided for you after the procedure.


  • Please consume all your prescribed medications (eg Aspirin and/or Clopidogrel) with plain water on the morning of your procedure except your diabetic drugs (particularly metformin). Bring all your medications with you.


  • Come in casual comfortable attire and bring your toiletries, an extra set of clothes & undergarments.

E. A SMALL IV CANNULA will be inserted in one of the veins of your hand to facilitate administration of medications.

Where is the procedure performed?

This test is usually done as a Day Surgery procedure in the Cardiovascular Lab in the X-ray department (not in the operating theatre).

How is the procedure performed?

Before the procedure

  1. You will be asked to empty your bladder before the procedure.
  2. You will change into a hospital gown and brought to the Cardiovascular Lab where your cardiologist together with a specialized team of cardiac technologists, radiographers and nurses will be on standby to do the procedure.
  3. The nurse will record your height, weight and blood pressure and insert an intravenous (IV) cannula into a vein in your arm.
  4. You will lie on a movable X-ray table equipped with X-ray cameras and heart monitors.
  5. Three electrodes (small flat sticky patches) will be placed on your chest wall and attached to an ECG monitor that charts your heart’s electrical activity during the test.
  6. A mild sedative may be given and this will make you sleepy but arousable.
  7. You will be covered with a sterile drape and a nurse will clean your wrist or groin (depending on the access site chosen by your cardiologist) with a cool antiseptic solution.

During the procedure

  • The procedure is broken up into 2 parts. The first part is obtaining vascular access and the second part is obtaining the coronary angiogram images.
  • Obtaining vascular access

A local anaesthetic is injected into the skin of the wrist (see above) or groin, causing a temporary stinging sensation. Once the site is numb, a small 2-3 mm plastic sheath is inserted into the radial/femoral artery.

  • This is a video presentation of obtaining the vascular access through the right radial artery.
  • Through this small sheath, catheters will be advanced to the heart under-X-ray guidance.
  • You should feel no more than a mild discomfort in your arm as the catheter moves up your arm and occasionally a warm sensation in your body during the procedure.
  • This typically takes about 5 mins to complete.
  • The following are videos demonstrating the movement of the catheters up the wrist under X-ray guidance.

Video 1:

Advancing the guiding catheter up the right arm to the heart

Video 2:

Advancing the diagnostic catheter to the heart

Video 3:
Advancing the diagnostic catheter to cannulate the left main coronary artery

Video 4:
Advancing the diagnostic catheter to cannulate the right coronary artery    

Obtaining coronary angiogram images

  1. Small amounts of dye will be injected to opacify the coronary arteries and sometimes the left ventricle under X-ray guidance.
  2. The X-ray camera will move over and around your body to take pictures from different angles.
  3. This process is also painless and you will not feel any discomfort.
  4. This step typically takes another 5 to 10 mins.

i. Left Anterior Descending (LAD) artery

ii. Left Circumflex (LCX) Artery

iii. Right Coronary Artery (RCA)

iv. Aorta and Left ventricle

Coronary angiogram videos taken by our interventional cardiologist Dr Ooi Yau Wei.

Video 1:
Coronary Angiogram of a normal Left Anterior Descending (LAD) Artery

Video 2:
Coronary Angiogram of a normal Left Circumflex (LCX) Artery

Video 3:
Coronary Angiogram of a normal Right Coronary Artery (RCA) 

Video 4:
Left ventriculogram – this allows doctors can see how well the heart pumps and how much blood the heart pushes out with each beat.

Are there any other tests done during a coronary angiogram?

Additional tests may be done if more information about your coronary arteries is needed to decide the severity of the blockage and/or plan your coronary angioplasty.

These tests may include but not limited to :

  • Fractional Flow Reserve (FFR) Study
  • Intravascular Ultrasound (IVUS)
  • Optical Coherence Tomography (OCT)

How does the doctor use the results to treat me?

Your cardiologist will explain to you the results once all the pictures have been satisfactorily obtained and discuss with you the options of treatment.

The options for treatment (often a combination of the following) include:

  • Lifestyle modifications with heart healthy diet and exercise
  • Optimization of medications
  • Coronary Angioplasty (stenting) or
  • Coronary Artery Bypass Grafting (CABG)

Your interventional cardiologist will proceed with coronary angioplasty in this same sitting if this option is indicated and once informed consent obtained from you.

What happens after the procedure is completed?

Coronary Angiogram 

  • The sheath in your wrist will be removed with a special closure device tightly compressing the site of puncture.
  • You will be brought back to the day surgery ward to rest for a few hours.
  • You will be able to have your breakfast or lunch with your medications.
  • Once the puncture site over your wrist is stable with no bleeding, you will be able to leave the hospital. it is important not bend your wrist for 6 hour and to not use your wrist for the next 24 hours.
  • Clear instructions about how to take care of the access site following the procedure will be given.
  • It is recommended that you do not drive after the procedure and have someone accompany you home after the procedure to rest.
  • You are encouraged to drink plenty of clear fluids to help clear the X-ray contrast (‘dye’) from your kidneys.
  • An appointment will be given for your follow-up visit.

Coronary Angioplasty (Stenting)

  • If Coronary Angioplasty (stenting) is performed, you will stay overnight for observation and discharged the next day if you are well.

More information

The Coronary Angiogram and Its Seminal Contributions to Cardiovascular Medicine Over Five Decades - https://www.ahajournals.org/doi/10.1161/01.CIR.0000024109.12658.D4

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