Coronary Angiography

Coronary angiography is an imaging test that shows whether the arteries supplying the heart muscle are narrowed or blocked. Conventional, catheter-based coronary angiography uses an injected contrast agent and X-rays to outline the coronary arteries, providing an anatomical assessment of coronary artery disease.

How the test reveals coronary disease

Coronary artery disease commonly develops when atherosclerotic plaques build up in coronary arteries. These plaques can narrow the channel through which blood flows and may reduce oxygen delivery to the heart muscle.

• A catheter is introduced through an artery, commonly at the wrist or groin, and guided to the openings of the coronary arteries.
• An iodinated contrast agent is injected, and moving X-ray images show the contrast-filled arterial lumen.
• The images identify the location, extent and severity of narrowing, including whether one or several major coronary arteries are affected.

How the findings guide treatment

Angiography helps doctors relate a patient's symptoms and other test results to coronary anatomy. Its findings support decisions about medicines, angioplasty with stenting, or coronary artery bypass surgery.

• In selected patients with acute coronary syndromes, urgent angiography can identify the artery responsible and guide restoration of blood flow.
• In stable disease, it may be used when symptoms persist despite treatment or when other investigations suggest high-risk disease.
• The distribution and complexity of narrowing help determine whether revascularisation, meaning restoration of blood supply through a procedure, is appropriate.
• Angiography is diagnostic, whereas angioplasty is therapeutic; angioplasty may follow during the same session when indicated.

What angiography cannot decide by itself

An angiogram primarily shows anatomy, not how much a particular narrowing limits blood supply. Finding a narrowing does not automatically establish that a stent is necessary.

• For an intermediate narrowing, fractional flow reserve, a pressure-based measurement obtained during catheterisation, can help assess its functional significance.
• Treatment decisions also depend on symptoms, evidence of ischaemia, heart function, coronary anatomy and the patient's overall condition.
• An angiogram without major arterial narrowing does not exclude all causes of myocardial ischaemia, including coronary microvascular dysfunction.
• Because the procedure is invasive and involves radiation and contrast, risks such as bleeding, allergic reactions and kidney injury must be weighed against its diagnostic benefit.