Australia needs a modern approach to assessing heart attack risk

Heart attacks are a leading cause of cardiac arrests and sudden death in adults, and can happen without prior warning signs.
 
Early diagnosis and assessment of cardiovascular risk along with the use of preventive measures are crucial for reducing the risk of heart attacks.
 
Coronary artery disease occurs due to the silent build-up of cholesterol plaques in the coronary arteries, increasing the risk of heart attacks, which can occur when a sudden rupture of plaque leads to abrupt blockage of the coronary artery.
 
What many people don’t know is that plaque rupture can happen even in coronary arteries with only mild build-up of plaque.
 
CT scanning of the heart has changed the way coronary artery disease risk can be assessed, by measuring the amount of calcium within the coronary arteries, which is a marker of plaque build-up. A calcium score of zero means that the risk of having a heart attack in the next five years is very low.
 
Doctors already use the calcium score to determine whether preventive medicines such as statins, to lower cholesterol, should be prescribed. However, it does not take into account plaque that does not have calcium in it.
 
Although the coronary artery calcium score is a very good starting point, especially in people who have no symptoms, a lot more information for assessing risk can be obtained from performing a CT coronary angiogram of the heart as well.
 
This is a quick and safe test where contrast is injected into a vein during the CT scan to provide a better picture of the coronary arteries and the characteristics of any plaque within them.
 
The location and severity of narrowing due to any plaque (including so called soft plaque which is not seen on calcium scans) can be accurately assessed, which can help determine whether more tests or treatment for the heart are needed.
 
Certain features which make a plaque more prone to rupturing and causing future heart attacks can also be seen on the CT coronary angiogram. Plaque with high-risk features is often termed ‘vulnerable plaque’.  
 
The American Heart Association journal Circulation recently reported that patients with low-attenuation plaque burden (a particular high-risk feature) greater than 4% were nearly five times more likely to have subsequent myocardial infarction.
 
The use of CT coronary angiogram of the heart provides a more personalised and modern approach to assessing the risk of having a heart attack. Artificial intelligence has also been integrated into CT scanning to further improve the way CT images are processed and to improve the diagnostic accuracy and precision.
 
Studies have shown that information provided by the CT coronary angiogram predicts risk better than traditional risk factors and risk calculators. At present, the CT coronary angiogram is reserved as a diagnostic test to rule-in or rule-out coronary artery disease when symptoms are present.
 
However, prognostic information can also be obtained from the scan.  
 
A scan showing no plaque in the coronary arteries means that the risk of having a heart attack in the next five years is very close to zero. Having even mild plaque in the arteries increases the risk of having a heart attack.
 
Importantly, coronary artery disease may not cause symptoms and can sometimes go undetected by stress tests, highlighting an advantage of CT coronary angiograms. As a diagnostic and risk assessment test in patients presenting with suspected coronary artery disease, the CT coronary angiogram gives doctors the opportunity to find plaque and look at its characteristics and for high-risk features.
 
Whilst coronary artery calcium score is a time proven test to assess risk in asymptomatic patients, it can miss soft plaques especially if a patient is having symptoms, and in such cases a CT coronary angiogram is required.
 
Crucially however, this technology exists and can diagnose life-threatening heart disease before it kills people.
 
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cardiology cardiovascular disease CT angiogram heart attack