Coronary angiography is the gold standard diagnostic investigation for coronary artery disease, providing direct visualisation of the coronary arteries and the degree and location of any narrowings or blockages. It is performed by injecting a radiocontrast dye into the coronary arteries via a catheter, while X-ray imaging (fluoroscopy) captures the dye outlining the arterial lumen in real time.
The procedure is performed in a cardiac catheterisation laboratory. A thin catheter is inserted into a peripheral artery (usually the radial artery at the wrist, as radial access is now preferred in most UK centres) and navigated under X-ray guidance to the openings of the left and right coronary arteries at the base of the aorta. Small amounts of contrast dye are injected while images are recorded from multiple angles, revealing the number, location, and severity of coronary stenoses (narrowings) and any complete occlusions. If intervention is needed, a stent can be deployed during the same procedure (see PCI).
Coronary angiography is a key step in the management of cardiac arrest survivors. Most resuscitated patients undergo urgent coronary angiography to determine whether a coronary artery blockage caused or contributed to the arrest. If a significant blockage is found, PCI can be performed immediately to restore blood flow. Coronary angiography also characterises ventricular function and helps rule out structural causes in survivors without obvious coronary disease.
Risks are low in experienced hands and include vascular access complications (bruising at the wrist or groin), allergic reaction to contrast dye, temporary kidney impairment, and, very rarely, stroke or arrhythmia. The procedure typically takes 30 to 60 minutes, and most patients return home the same day.
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