Coronary angiography

When is coronary angiography indicated?

Coronary artery disease is typically diagnosed based on an assessment of symptoms, a clinical examination and findings from an exercise ECG test. In most cases, coronary angiography is not necessary. However, coronary angiography is indicated when your physician suspects that you might benefit from invasive treatment such as balloon angioplasty or coronary artery bypass surgery. Before these procedures can be performed, the condition of your coronary arteries must be thoroughly examined. In cases, where the cause of serious symptoms cannot be reliably determined, coronary angiography serves as a diagnostic tool. If your condition is stable, coronary angiography is classified as elective and non-urgent. Nevertheless, it is typically performed within a few weeks and at the most three months after it has been deemed necessary. When your condition is unstable and symptoms occur acutely or have taken an abrupt turn for the worse, coronary angiography is performed one to two days after you have been referred for treatment or admitted to a hospital. In urgent situations, coronary angiography is performed as an emergency operation.


Preparations for coronary angiography

Coronary angiographies are performed at outpatient clinics. Patients are admitted on the morning and discharged later the same day. Patients requiring preliminary care, such as fluid therapy, or who need to be monitored after the operation, are admitted to a ward for a day or two. Preparations include an appointment with a nurse at the Cardiology Outpatient Clinic a few days before the procedure is scheduled to take place. The nurse explains the procedure and what to expect, and makes sure that the necessary examinations have been performed and laboratory tests taken.
On the day of the operation, you will be premedicated with a sedative and an antihistamine preparation to suppress possible allergic reactions to the contrast medium. If you have a history of severe allergic reactions to iodinated contrast medium, the risks and benefits associated with the procedure are carefully assessed and discussed with you. If you and your physician agree, coronary angiography can be performed under potent anti-allergy drugs which prevent allergic reactions.


The operation and the assessment of results

Coronary angiography is performed under local anesthetic. A catheter is passed into an artery in your arm (radial artery) or groin (femoral artery). The cardiologist decides which artery to use and the assisting nurses will prepare you accordingly. The selected artery is punctured with a needle. A sheath with very thin walls is inserted into the artery. A guide wire and imaging catheter are then inserted through the sheath and passed towards the coronary arteries to the root of the aorta under X-ray guidance. The soft tip of the catheter rarely causes vascular injuries. Iodinated contrast medium is injected into the coronary artery and X-ray images showing how the fluid travels in the vessels are taken and saved on a computer. A series of X-ray images are taken from different angles and from both coronary arteries. The images are reviewed immediately after they have been taken and the severity of the detected stenoses is either visually estimated or calculated using the computer software. Coronary angiography can be complemented with coronary pressure measurements and intravascular ultrasound imaging. The X-ray images and any ultrasound images are digitally archived and saved on a disc if necessary. 

Coronary angiography is used to diagnose coronary artery disease and in case of a positive diagnosis, to determine whether invasive treatment is required or not, and if yes, which is the better option – balloon angioplasty or coronary artery bypass surgery. The available options are discussed with you and the treatment decision is based on these discussions. In some cases, the options are first discussed with heart surgeons before an expert recommendation is presented to you. Sometimes the best option is to continue with drug therapy.

Risks associated with coronary angiography

There are risks associated with coronary angiography. Pain, bruising and swelling are common and usually harmless consequences of the procedure. However, bleeding from the puncture site may prolong the length of the hospital stay. On rare occasions the artery may become ruptured, in which case it will need to be closed surgically to stop the bleeding. Life-threatening arterial bleeding to the pelvic area or the area behind the peritoneum is very rare. Coronary angiography may cause arrhythmias which are treated during the operation either with medications or by using defibrillation. Anxiety and pain caused by the puncture might trigger a reflex exciting the vagus nerve activity, resulting in decreased blood pressure and reduced heart rate. If this happens, you are likely to feel weak and nauseous. However, these symptoms are quickly corrected with infusion and vagus nerve blocking medication. This does not require the examination to be discontinued.
If the coronary arteries are seriously diseased with very fragile walls, the tip of the catheter may cause topical injuries. When the aorta is atherosclerotic and its inner surface is rough, calcification chips, cholesterol mass or a local blood clot might be released into the circulation, causing disorders of the cerebral circulation or a brain infarction. Death during coronary angiography is an extremely rare complication and is typically associated with the treatment of seriously ill patients.

The contrast medium might have a negative effect on existing renal insufficiency. Appropriate fluid therapy before and after the procedure decreases the risk of renal damage.  The combined risk of the most severe complications of coronary angiography (severe bleeding, brain infarction, death and severe renal damage) is approximately 0.5 to 1 per cent.