CT scans for artery calcium are a newer way to look for plaque. The test is non-invasive and takes about 15 minutes. I think these tests have potential, but also need more development. Why? I see 5 Important Issues:
1. Most of those tested had no symptoms, such as chest pain, shortness of breath, dizziness, or other symptom of heart disease. That skews the numbers away from heart attacks or events and their predictability.
In fact, correlations between specific scores and cardiac events is still unclear, especially for numbers below about 400. Take a score of 250. What does that signify? It’s near the middle of the 101-400 category (called moderate plaque), but are there obstructions or vulnerable plaques? Is there fast or slow growth of plaque? How long has the plaque been there? The scans can’t answer these important questions.
2. Because the scores are skewed toward healthy people without symptoms (they use your age and score to put you in a percentile grouping), your ranking can also be skewed. Think of how unequal these calcium ranges are:
0-10 (minimal plaque)
11-100 (mild plaque)
101-400 (moderate plaque)
401-above (extensive plaque)
These categories become more broad above 100. Ask yourself if 101 is equal to 350 (both in the moderate plaque category)? Is 401 the same as 650 (both in the extensive category)? Of course not. Why weren’t these categories set up with smaller increments of 50 or 100?
When these unequal categories are graphed, you can see how vague the scores are. The graphs have equal spacing for 0-10 (10 total points), 11 to 100 (90 points), and 101-400 (300 points). So for the lower range of the 101-400 section, say 150, the plaque will probably be non-obstructive, allowing good blood flow, but the score won’t tell you for sure. And tests for actual obstructions (like angiograms) cost thousands, and are usually done when blockages are already suspected.
Scores above 400, especially as they climb toward 1,000, seem to have higher probabilities for artery narrowing (stenosis) and a cardiac event, such as a heart attack, but even that outcome is not certain. People in this category will tend to have more symptoms, but calcium scans for people in these higher risk categories are not always useful. You might undergo other tests to determine actual blockages or degree of stenosis.
Critical beat:
The American Heart Association recently recommended that people in the intermediate risk in the Framingham Risk assessment (a 10% to 20% heart attack risk in 10 years) have scans. (See this site for your own assessment.):
http://hp2010.nhlbihin.net/atpiii/calculator.asp?usertype=prof
The AHA has determined that people in low or high risk categories will not benefit from scans as much. Their position validates much of what I’m saying (See page 5 for the remaining points on this topic).
Disclaimer: The information contained on this website is for educational use and is not intended as a substitute for the diagnosis or treatment of a licensed professional.
© 2008-2010 by Steve/Beat Heart Disease
About Me
- beatheartdisease
- Where to begin? I’ve been interested in health, diet, and nutritional supplements for 20 years, because I had a childhood illness. I learned what it’s like to be hospitalized, go through shots, surgeries, etc. It was a great lesson in what happens when you lose your health. I’ve had a decent diet for years, but had some bad habits in my 20s and 30s: I smoked cigaretts, ate fast food, etc. When I had an initial CT scan, the scan showed some plaque so I did more research into how I might reverse it. I was able to reverse it quite a bit! This blog is a result of that research along with a moderate diet and supplements. Feel free to e-mail me with questions at the contact address!
