A heart calcium scan: What does it mean?

inflammation:

Just like the "bone spur" of the heel ligament, inflamed soft tissues become calcified over time. Some patients ask, "Should I stop drinking milk?" The calcium isn't the problem. Inflammation is.

Calcium in arteries is a marker for inflammation. Although it is not the source of the inflammation, calcium is a very useful marker.

Inflammation, or plaque in the arteries is caused by risk factors like high blood pressure, smoking, diabetes and high cholesterol.

Although easy and popular, risk factor-based calculators are not as accurate at predicting heart attacks as the actual patients' arteries (1, 2). 

What does inflammation in the arteries mean?

Arterial inflammation means higher risk for a CV event.

Once you know you’re at higher risk, there are two important decisions to make, which means asking some hard questions in two arenas. Both areas are important. The first is intensely personal. If you knew that it was possible to reduce your risk (and it is), then what would you be willing to do to achieve that?

The second decision is a medical decision, and it is absolutely essential if you are to actually reduce your event risk. You must make a commitment to search for and to find the answers to this question:

Why is my risk high?

What are the forces behind my risk? Where is my risk coming from?

This is your personal quest. If you don’t find the answers to the “Why is my risk high?” question, then you won’t know what to do about it. We’ve done this many times. We can guide you through a process of asking the right questions, like, for example: “What role do my genes play?”

Why is it so important to have someone with experience guide you through this process? Because right now our standard of care is to focus on cholesterol and stents. (3,4)

Examples of Heart Calcium Scans

Coronary arteries are normally clean, with no calcium.  Calcification appears as white spots in the arteries.

pick the right ct machine:

Because the coronary arteries are in motion with every heart beat, if the CT detection ring moves around the patient's chest too slowly, artery images are blurred. So these slower CT heart scans miss too many high-risk patients, because they are not as sensitive in detecting calcium as the Electron Beam CT with no moving parts, which captures images at the speed of light.

In addition to being faster, the electron beam CT gives less radiation compared to conventional CT scan machines. If electron beam CT (or EBCT) is not available in your area, ask how many slices the CT scanner makes per second. How much more motion artifact do you think you'll see with a CT that makes 8 or 16 slices per second compared to a faster one that makes 320 slices per second? Although 64 slices per second gives reliable results when a patient's pulse is not too fast, the faster the CT, the better quality pictures you'll get. You can’t get faster than the speed of light.

Even with 320 slices per second, beta blocker drugs are often used by the radiologist to slow the pulse to get better quality images. Don't be afraid to ask your primary care doctor for a beta blocker to take with you, in case your pulse is too fast for the exam.

What about a zero calcium score?

Calcium is a rather late development in the arterial inflammatory process. So a zero calcium score doesn’t mean you have no risk.

In one study of 1,688 younger patients with a major adverse cardiac event (sudden cardiac death, heart attack, unstable angina, stent or bypass), one third of them had a zero calcium score. (5)

So an alternative testing method (ultrasound) can verify that your event risk is truly low.

Why has early screening (looking for heart disease before a heart attack) been so controversial?

Look for this movie on YouTube:

references

1. This prospective study of 44,000 patients with no symptoms and no history of coronary disease compares the relative predictive value of risk factors versus heart calcium scores. "Our study findings support a paradigm shift in CVD risk assessment from RF-based (risk factor) approach to detection of sub-clinical atherosclerosis burden as evident by the fact that a significant proportion of those with no RF (risk factors) have a severe amount of coronary atherosclerosis and have a high risk for all-cause mortality. The higher precision of CAC (coronary artery calcium) relative to RFs (risk factors) for identifying at-risk individuals may be because of the fact that CAC is a measure of actual disease that occurs further down the causal pathway than the presence of RFs that are mere surrogates for this process." (parentheses and italics added) Nasir, et al. Interplay of coronary artery calcification and traditional risk factors for the prediction of all-cause mortality in asymptomatic individuals. Circ Cardiovasc Imaging. 2012;5:467-473

2. Hecht, et.al. Coronary artery calcium scanning: clinical paradigms for cardiac risk assessment and treatment. Am Heart J. 2006;151:1139-46

3. This study showed that half of patients hospitalized with heart attacks had a normal cholesterol. Of those patients with normal cholesterol values, most had unusual risk factors that are not generally tested for. Sachdeva et al. Lipid levels in patients hospitalized with coronary artery disease: an analysis of 136,905 hospitalizations in Get With The Guidelines. Am Heart Journal. 2009;157(1):111-117.e2.

4. Both the COURAGE trial in 2007, and the ISCHEMIA trial (presented at the AHA meeting in Nov., 2019), showed that stents don’t save lives or prevent heart attacks in patients with no chest pain. Boden, William, et al. the COURAGE Trial Research Group, Optimal Medical Therapy with or without PCI for Stable Coronary Disease, N Engl J Med 2007; 356:1503-1516 DOI: 10.1056/NEJMoa070829

5. Omar Dzaye, et al. Modeling the Recommended Age for Initiating Coronary Artery Calcium Testing Among At-Risk Young AdultsJ Am Coll Cardiol. 2021 Oct, 78 (16) 1573–1583