Coronary artery calcium scanning may reliably rule out the need for statins, study shows

A new German study on heart disease primary-prevention for intermediate risk patients has found that getting a coronary artery calcium (CAC) score, in addition to blood sugar markers and lipid levels, can refine the clinical prediction of coronary events.
The research, published online in JACC: Cardiovascular Imaging, shows that CAC scanning may improve the classification of patients as high or moderate risk for adverse cardiovascular outcomes, whether on statin therapy or not.
The CAC score has been around since the 1990s but it has really come on the scene lately. It is powered by electron-beam computed tomography (CT) and used to measure in a couple of minutes the plaque build-up inside the arteries to know where a patient’s heart health stands.
As plaque build ups, it forms a fatty streak that accumulates calcium. CAC scanning can see the calcium pop up before it shows up in a stress test, electrocardiogram (ECG) or any other test commonly used to make a diagnosis.
Because CAC scoring is so much more precise, researchers believe it may also tell a clinician whether a particular risk-factor modification (such as lifestyle change or medication) initiated by a patient is having a positive impact or no effect at all on plaque reduction.
Low-risk patients (based on low 10-year event rates) could also opt out of a lifelong statin treatment if damage in the arteries is not yet seen on CAC scans.
The lead author of the study, Dr Amir A Mahabadi, and his colleagues from the University of Disburse-Essen have tested the effectiveness of CAC imaging in a study involving 3,745 participants of the 2000 Heinz Nixdorf Recall study.
Their goal was to quantify CAC scoring differences and statin recommendation among participants when applying the American Heart Association/American College of Cardiology (AHA/ACC) or the European Society of Cardiology (ESC) guidelines.
AHA/ACC guidelines are known to advise statin therapy more widely than ESC guidelines.
The results revealed that of the 3,745 individuals (all without lipid-lowering therapy or known cardiovascular disease), 1,288 (34.4 per cent) met criteria for statin therapy under ESC guidelines, while 2,101 (56.1 per cent) did so under AHA/ACC guidelines.
A total of 241 hard cardiovascular events occurred during a 10.4 years follow-up. Sixty participants with coronary events did not fit statin indication under ESC, while only 19 events occurred among participants without statin indication under AHA/ACC.
A healthy CAC score target that implies no evidence of cardiovascular disease is usually comprised between 0 and 10. The researchers found that participants with CAC scores of 400 or higher, which is considered severe, experienced a 10-fold higher event rate compared with participants with a CAC score of zero. The frequency of events was low (3.3 per cent or lower) in participants whose CAC score fell below 100.
According to both guidelines, the frequency of zero or low CAC score in patients with statin recommendation is high, while this group has an overall low event rate.
This suggests that a CAC score may help identify patients who are truly at low risk despite being statin eligible under the ACC/AHA prevention guidelines.
The findings also show that CAC scoring is more reliably indicative of both status and future risk for heart events and can lead to significant improvement of risk predictio, especially in addition to European recommendations.