Statins And Your Calcium Scores

Coronary artery disease with calcium
Calcium in coronary arteries. ZEPHYR/Getty Images

 

Question. Two years ago my doctor put me on 80 mg of atorvastatin because my cholesterol was up, and my cardiac calcium scan showed a score of 200. Since then my cholesterol has gone down nicely — but when we repeated a calcium scan last week my calcium score was up to 290! If the statin is working, why is my calcium score going up so much? Is my coronary artery disease getting worse?

Answer. A “calcium scan” is an x-ray technique to assess the amount of calcium deposits in the coronary arteries. The presence of calcium in the coronary arteries indicates that atherosclerosisis present. Further, the calcium score (which estimates the amount of calcium in the arteries) roughly corresponds to the severity of coronary artery disease, as follows:

  • 0 — no identifiable disease
  • 1 to 99 — mild disease
  • 100 to 399 — moderate disease
  • 400 or higher — severe disease

Doctors sometimes use the calcium score to help decide whether to recommend treatment with a statin. Statins often reduce the risk of heart attacks. 

However, seemingly paradoxically, sometimes the calcium score increases with statin therapy. The tendency of the coronary artery calcium score to increase with statin therapy has been an area of controversy and concern among cardiologists. 

As it turns out, at least some evidence now suggests that this may be a good thing. It may indicate that the statins are stabilizing coronary artery plaques.

Some Background

Atherosclerosis produces plaques in the walls of arteries, including the coronary arteries. These plaques can grow large enough to partially obstruct the artery and produce symptoms, such as angina or claudication. However, the real problem with these plaques is that they can suddenly rupture, causing a sudden occlusion of the artery — which often leads to a heart attack, or a stroke.

Plaques are deposits of several materials, including lipids, inflammatory cells, fibrotic cells, and calcium. It is the calcium in atherosclerotic plaques that is detected by a cardiac calcium scan — the higher the calcium score, the more extensive is the atherosclerosis.

So, when your doctor started you on atorvastatin, he or she was not merely treating your cholesterol levels, but was also treating your atherosclerotic plaques.

Statins And The Calcium Score

Several studies have now shown that treating a patient who has atherosclerosis with statins can increase the cardiac calcium score.

Since statins are thought to help prevent and even to help reverse coronary artery disease, this result seems paradoxical. In 2015, a study was published in the Journal of the American College of Cardiology which helps to clarify what this increase in calcium means.

Investigators reviewed eight separate studies which had used intravascular ultrasound (IVUS, a catheter technique) to assess the size and composition of atherosclerotic plaques in patients treated with statins. They found two things. First, high-dose statin therapy tended to shrink plaques. Second, while the plaques were shrinking, their composition was changing. After statin therapy, the volume of lipid deposits within plaques diminished, and the volume of fibrotic cells and calcium increased. These changes — converting an unstable “soft” plaque to a more stable “hard” plaque — may render a plaque less prone to sudden rupture. (This postulate is consistent with the fact that statin therapy significantly reduces the risk of heart attacks in patients with coronary artery disease.)

In summary, current evidence supports the idea that statin therapy not only reduces cholesterol levels, but also changes existing plaques to make them less dangerous.

As part of this process, the plaques may become more calcified — and thus, calcium score goes up. An increasing calcium score with statin therapy, therefore, may indicate treatment success, and should not be a cause for alarm.

While this theory is not settled science, at this point it best fits the available evidence.

A Word From Verywell

A cardiac calcium scan can be a useful tool in assessing the presence or absence of coronary artery disease. If calcium is present, atherosclerosis is present - and aggressive lifestyle changes are in order. In addition, strong consideration should be given to statin therapy and prophylactic aspirin.

But, once statin therapy has begun, interpreting subsequent calcium scans becomes a problem. If the calcium score goes up, it may not indicate worsening CAD, but rather, is likely to be a positive effect of statin treatment.

As a general rule, doctors should not order tests that they know ahead of time they probably will not be able to interpret. While a screening calcium scan makes a lot of sense for people who are at some risk for coronary artery disease, repeating those calcium scans after statin therapy has been initiated may just create anxiety, without adding any useful information.

View Article Sources
  • Puri R, Nicholls SJ, Shao M, et al. Impact Of Statins On Serial Coronary Calcification During Atheroma Progression And Regression. J Am Coll Cardiol 2015; 65:1273-1282.
  • Shaw LJ, Narula J, Chandrashekhar Y. The Never-Ending Story On Coronary Calcium. J Am Coll Cardiol 2015; 65:1273-1282.