Coronary angiography is a minimally invasive cardiac procedure that uses X-ray imaging and contrast dye to detect narrowed or blocked coronary arteries, guiding decisions on treatment such as stents, coronary artery bypass graft (CABG) or medications. Patients can usually go home on the same day.

The heart is a complex network of coronary arteries. Over time, fatty deposits called plaque can build up in the arteries, causing narrowing and reducing blood flow. In severe cases, a blockage can trigger a heart attack. 

Coronary angiography is considered the gold standard for diagnosing coronary artery disease (CAD). The test can reveal where the narrowings are, how severe they are and exactly which arteries – typically the major ones shown as the darkened lines in the scan images above – are affected. Once the narrowing or blockage is treated, symptoms such as chest tightness, is usually resolved.

Functional coronary angiography

In cases where patients continue to experience symptoms, but their scan results do not reveal blockages in their major coronary arteries, doctors may recommend functional coronary angiography after careful medical evaluation. This is performed as part of the standard coronary angiography by using specialised pressure wires and medication to measure changes in the blood flow and pressure in the microscopic blood vessels invisible on a scan. The risk of functional coronary angiography is low and is similar to that of a standard coronary angiography.

How does coronary angiography work? 

A thin plastic catheter (approximately 2mm in diameter) is inserted through a blood vessel in the wrist or groin and guided toward the heart using X-ray imaging. Contrast dye is then injected into both the left and right coronary arteries and moving X-ray images are captured to reveal any blockages or abnormalities. A second catheter may be used to assess heart muscle function.

Benefits of coronary angiography

Coronary angiography offers several advantages in diagnosing and managing coronary artery disease (CAD) compared to other diagnostic tests:

Accurate diagnosis: Provides detailed and accurate information on the location and severity of blockages in the coronary arteries, helping cardiologists plan appropriate treatment strategies.

Direct Visualisation: Unlike other non-invasive imaging tests, coronary angiography allows cardiologists to see the coronary arteries directly, enabling precise identification of blockages or abnormalities.

Immediate Treatment: If significant blockages are detected, immediate treatment options such as angioplasty and stenting can be performed in the same session, avoiding the need for patient to return another day.

Risk Stratification: Helps identify high-risk patients who may benefit from aggressive medical therapy or invasive interventions.

Comprehensive Evaluation: Provides a comprehensive evaluation of the coronary arteries, including assessing heart muscle function, congenital anomalies or structural abnormalities in one procedure.

Coronary Angiography – Limitations

What are the limitations of coronary angiography? 

• Invasive procedure: Involves insertion of a small catheter into the blood vessels.

• Radiation exposure: Uses X-rays.
  

Coronary Angiography – Considerations and Risks

What are the considerations and risks associated with coronary angiography?

Certain patients may not be suitable candidates for this procedure:

• Allergy to contrast dye or iodine: The procedure involves injection of iodine-based contrast hence individuals with known allergies to X-ray contrast or iodine compounds should not undergo coronary angiography.
• Severe heart, kidney or lung failure: Individuals with unstable health conditions face increased potential risk and may not be suitable candidates for the procedure.
• Bleeding disorders or anticoagulant use: Individuals with such disorders have elevated risk of bleeding complications during or after the procedure, making them unsuitable for coronary angiography.
• Pregnancy: Coronary angiography is generally not recommended for pregnant women due to the potential risk that radiation and contrast dye pose to the fetus.
• Severe renal impairment: Patients with severe renal impairment may be at increased risk of complications from the contrast dye used during the procedure.
• Unstable angina: Individuals with unstable angina, a type of chest pain that occurs at rest or with minimal exertion, may not be suitable for the procedure until their condition stabilises.

Coronary angiography is generally a very safe procedure. However, rare but serious complications such as stroke or heart attack, arrhythmias and major bleeding, can occur in less than 1% of patients undergoing the procedure. The overall risk is dependent on the individual’s health condition and the complexity of the coronary artery blockages.

​How to prepare for coronary angiography?

• Fasting: Abstain from food for 6 hours before the procedure. A full breakfast is allowed if the procedure is scheduled in the afternoon.
• Medications: Continue all regular medications unless your doctor advises otherwise.
• Allergies: Inform your doctor of any known allergies, especially to contrast dye or iodine.
• Sleep: Get adequate rest the night before; sleeping medication can be requested if needed.
• Day of procedure: Remove dentures, contact lenses, and jewellery. Do not bring valuables.

What can you expect during coronary angiography?

On the day of procedure, you will be asked to remove your dentures, contact lenses and any jewellery. Please do not bring any money or valuables on the day of your procedure.

During the Procedure
Local anaesthetic will be given to numb the area of injection, you may be slightly sedated but awake. A soft plastic tube around 2mm in diameter will then be inserted through a blood vessel in the groin or wrist. This tube will be passed towards the heart using x-ray guidance.

After the tube enters the blood vessels of the heart, dye will be injected into both the right and left blood vessels of the heart via the tube. Moving images of the arteries would be taken using X-ray. Another tube may also be passed into the left heart to assess the heart function.

What to expect after the procedure?

• Your cardiologist will review the images and recommend next steps.
• Most patients are discharged on the same day.
• If a severe blockage is found, coronary angioplasty may be performed immediately.
• If surgery is required, you will be scheduled for a CABG surgery on a separate date.
• Plan to rest for 24 - 48 hours after discharge.

Watch our video on coronary angiography:

What is Coronary Angiography and Angioplasty?

Frequently Asked Questions