Cardiac Catheterization and Coronary Angiography

Cardiac catheterization threads a thin catheter through a peripheral artery or vein to the heart and coronary arteries, allowing direct measurement of intracardiac pressures and, with injected contrast under X-ray (coronary angiography), visualisation of the coronary lumen. It remains the reference standard for defining coronary anatomy and is the gateway to percutaneous intervention.

Definition

Cardiac catheterization is the invasive introduction of catheters into the heart and coronary arteries to measure pressures and flow and, by injecting radiographic contrast (coronary angiography), to image the coronary lumen and define obstructive disease.

Scope

This topic covers invasive catheter-based cardiac assessment: the access and catheter technique, coronary angiography as the anatomical reference standard, invasive physiology such as fractional flow reserve, and how invasive findings relate to revascularisation decisions. It is framed as a reference topic and does not provide procedural protocols or patient-specific indications.

Core questions

• How does invasive angiography define coronary anatomy more directly than noninvasive imaging?
• What does invasive physiology, such as fractional flow reserve, add beyond the angiographic image?
• How do invasive findings inform the choice between medical therapy and revascularisation?

Key concepts

• Vascular access (radial or femoral)
• Coronary angiography
• Intracardiac and intravascular pressure measurement
• Fractional flow reserve
• Anatomical reference standard
• Gateway to percutaneous coronary intervention

Mechanisms

A catheter is advanced under fluoroscopic guidance from a radial or femoral access site to the aortic root and selectively into the coronary ostia; injected iodinated contrast opacifies the lumen so that stenoses can be seen and graded on X-ray cine angiography. Catheters can also measure pressures within chambers and great vessels. Because the angiogram shows the lumen but not the functional significance of a stenosis, a pressure-sensing wire can compute fractional flow reserve - the ratio of pressure distal to a lesion relative to proximal during maximal hyperemia - to determine whether a stenosis is flow-limiting (Tonino, 2009).

Clinical relevance

Invasive angiography and physiology define coronary anatomy and lesion significance and guide revascularisation decisions in both chronic and acute coronary syndromes (Neumann, 2019; Byrne, 2023). Landmark trials such as FAME (Tonino, 2009) and COURAGE (Boden, 2007) shaped how invasive findings are used. The entry describes the modality and is not a basis for individual procedural decisions.

Evidence & guidelines

The use of invasive angiography and physiology in revascularisation is governed by the ESC/EACTS myocardial revascularization guideline (Neumann, 2019) and the ESC acute coronary syndromes guideline (Byrne, 2023). FAME established fractional flow reserve guidance (Tonino, 2009) and COURAGE clarified the role of PCI versus medical therapy in stable disease (Boden, 2007).

History

Catheterisation of the human heart dates to the early twentieth century, with self-experimentation demonstrating that a catheter could safely reach the right heart; selective coronary angiography was developed in the late 1950s and, together with X-ray contrast imaging, made the coronary lumen directly visible, founding interventional cardiology.

Debates

Anatomic stenosis versus functional significance

Because an angiographically visible stenosis may or may not limit flow, whether to revascularise on the basis of anatomy alone or to require physiological confirmation such as fractional flow reserve has been a central question, with trials supporting physiology-guided decisions.

Seminal works

• tonino-2009
• boden-2007

Frequently asked questions

What is coronary angiography?

It is an X-ray imaging technique in which contrast dye is injected through a catheter into the coronary arteries to visualise their lumen and identify narrowings; it is the reference standard for defining coronary anatomy.

What does fractional flow reserve measure?

Fractional flow reserve uses a pressure-sensing wire to compare blood pressure beyond a coronary narrowing with that before it during maximal flow, indicating whether the narrowing actually limits blood supply.