Coronary artery disease (CAD), atherosclerosis
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Research lead by a team from Charité–Universitätsmedizin Berlin, Germany has shown that coronary artery calcium scoring with CT can identify patients identify which patients are at a very low risk of heart attack or stroke. The findings may one day help patients with stable chest pain, but a low risk score, to avoid invasive treatments such as coronary angiography.

The finding are published today in Radiology, the journal of the Radiological Society of North America

“Coronary artery calcium is a strong and independent predictor of cardiovascular events,” said study first author Federico Biavati, an MD, PhD candidate in the BIOQIC research training group and a radiology resident at Charité–Universitätsmedizin. “The presence of coronary artery calcification indicates that atherosclerosis may have been present for some time.”

Coronary artery calcium scoring was first detailed in research by Arthur Agatston and Warren Janowitz in 1990, as a method to noninvasively measure the amount of calcium in heart arteries. From this research, they developed the Agastson scale to quantify the level of calcification. A score of 1 to 399 on the scale indicated moderate amount of plaque, while scores above 400 indicated a higher burden.

Further, a complete absence of coronary calcification is a strong indicator of the absence of advanced coronary atherosclerosis, but for patients with stable chest pain, the role that coronary artery calcium plays in heart health is less clear. Stable chest pain is defined as a recurring, but temporary condition that can be triggered by stress, exercise, or cold weather.

To better understand the potential prognostic value of coronary artery calcium scoring with CT, the investigators assessed 1,749 patients over the age of 60 for major coronary events. The patients were already a part of the DISCHARGE trial that includes 26 centers in 16 European countries. It was created to examine for which patients with suspected coronary artery disease based on stable chest pain, cardiac computed tomography (CT) or cardiac catheterization is best suited and is based on the single-center experience with the CAD-Man study at Charité.

Patients in this new trial had stable chest pain and had been referred for coronary angiography, an invasive procedure in which a catheter is threaded to the heart using X-ray as a guidance tool. A contrast agent is then injected via the catheter to aid in visualization of the heart’s arteries. The team then stratified the patients into three groups indicating low-risk, intermediate-risk, and high-risk categories based on their Agatston scores. Patients were then followed for three-and-a-half years to record any major adverse coronary events.

Those patients with a coronary artery calcium score of zero showed very low risk of major adverse cardiovascular events at follow-up. Only four of the 755 participants in the group (0.5%) had a major adverse cardiovascular event during the follow-up period. The group also only had a 4.1% risk for obstructive coronary artery disease.

“This finding may indicate that a zero coronary artery calcium score can play a larger role in patient management strategies,” said study leader Marc Dewey, MD, professor and vice chair of radiology at Charité. “The findings suggest that patients with stable chest pain and a coronary artery calcium score of zero may not require invasive coronary angiography using cardiac catheterization because the risk of cardiovascular events is so low.”

In the group with scores from 1 to 399, 14 of the 743 patients experienced a cardiac event representing a risk of 1.9%; and there were 17 cardiac events in the 251 patients comprising the over 400 coronary artery calcium score group, showing a significantly higher risk of 6.8%.

While the research provides a strong signal that coronary artery calcium scoring could help inform future treatment decisions and reduce unnecessary invasive angiograms, the team said more research is needed before moving this method into clinical care.

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