New non-invasive method for diagnosing coronary artery disease

Patients seeking an explanation for their chest pain may soon be able to avoid invasive diagnostic procedures, with researchers having established that the reliability of non-invasive coronary computed tomography (CT) angiography is in some cases as good as that of coronary angiography.

Symptoms such as dull chest pain or a feeling of tightness in the chest may be indicative of coronary artery disease (CAD) — a condition which develops when a narrowing of the coronary arteries limits the blood supply to the heart muscle. In the worst-case scenario, CAD can lead to a life-threatening heart attack or sudden cardiac death. Prompt diagnosis is therefore essential.

Until now, patients with suspected CAD have often been examined using cardiac catheterisation for coronary angiography — a procedure that involves a catheter being inserted into a blood vessel via a small incision in the groin or arm and then advanced to the heart. The advantage of this method is that it combines diagnosis with treatment — if a narrowed segment is detected, the intervention to open up the affected artery can be performed immediately — but the procedure is not without its risks and, out of a total of 880,000 patients who undergo the procedure in Germany every year, 58% do not require such an intervention.

An international research consortium, led by Charité – Universitätsmedizin Berlin, has now been able to show that, in certain patients, an equally accurate diagnosis can be achieved using cardiac CT angiography — a non-invasive, gentle imaging method that only lasts a few minutes. The technique involves a circular X-ray machine taking 1000 images per second from various angles. These images are then combined to produce a 3D reconstruction of the heart and contrast agents are used to make the coronary arteries clearly visible.

Research groups from 22 countries worked together to analyse the data of more than 5300 patients from a total of 65 completed studies. Their analysis, published in The BMJ, revealed that coronary CT angiography is a suitable diagnostic technique in patients with a low to intermediate probability of CAD.

“Our work shows that, in both men and women, this method is capable of clearly visualising narrowed segments,” said Robert Haase, first author on the study and a member of lead author Prof Marc Dewey’s research group.

Prof Dewey added, “Physicians can determine a patient’s probability of having CAD using individual factors such as age, sex and type of chest pain. If this probability is between 7 and 67%, coronary CT angiography will provide a reliable diagnosis as to whether or not the patient has narrowed arteries. Cardiac catheterisation is indicated in patients with higher probabilities, as these patients are likely to need an intervention.”

Image caption: Coronary CT angiography generates thousands of X-ray images which are used to generate a 3D representation of the heart. This allows the visualisation of narrowed (arrow) blood vessels (grey). Image credit: Dewey/Charité.

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