Detecting Heart Disease Noninvasively Post 2

Only about 50 EBCT clinics currently exist in the US, but experts predict that number will double in the next year or two. If you’re serious about maintaining a healthy heart, does it make sense to visit an EBCT center for a quick, painless peek at your coronary arteries? Would your doctor refer you to one of these clinics? Should people with cardiomyopathy ask their cardiologists about EBCT?


EBCT is a new, noninvasive tool with the potential to help people with coronary risk factors answer the question, “Am I actually developing heart disease?” Research has shown that when there are small amounts of calcium in the walls of coronary arteries, there’s likely to be fatty plaque. And the more calcium that EBCT detects, the more likely it is that there’s a major blockage somewhere in the coronary arteries.

The most commonly used form of EBCT, the noncon trast variety, measures this calcium accumulation but can’t yet determine the location of blockages. The still-experimental contrast EBCT can locate blockages, but it requires the patient to have an IV (to infuse a chemical tracer) and the doctor to use a sophisticated computer program to interpret the data. As we saw in the NEJM study, technical difficulties with this process meant that only two thirds of patients had an adequate scan. So at this point, contrast EBCT is a very promising research tool, but it won’t yet replace the angiogram.

My patients often ask me whether it’s worth getting the regular, noncontrast form of EBCT that they’ve read about in the newspaper. They know they’ll have to pay for it themselves. We discuss how the test is done and what it means — that the calcium score is not a yes or no answer about the risk of a heart attack. For example, it can suggest that a person has plaque in his or her arteries but can’t tell us whether that plaque is interfering with blood flow to the heart muscle, which would spur us toward more aggressive testing and treatment. An angiogram, however, would give us this information.

Also, a low calcium score doesn’t let a person off the hook. People with low calcium scores can — and do — have heart attacks, raising the danger that someone who gets the allclear on an EBCT scan might wrongly think they can slack off on efforts to live a healthy lifestyle. In fact, studies show that the standard risk factors (such as high cholesterol and blood pressure) are just as reliable as EBCT at predicting a person’s risk of heart attack. In the end, I generally don’t recommend EBCT to my patients, but I am very willing to analyze the results if a patient decides to get a scan.

If you choose to have an EBCT scan to screen for coronary artery disease, I applaud your active participation in your own health care. I would caution you, though, that the most useful result of the test would be a “negative” or “normal” EBCT. This encouraging result would mean that you probably don’t have serious blockages. Your doctor likely won’t recommend further testing, and you’ll be able to continue focusing on symptoms and modification of risk factors. Likewise, if you have cardiomyopathy without any chest pain, a negative EBCT scan might let you avoid an angiogram.

A positive test, on the other hand, means you’ll need to review the results with a knowledgeable physician who can best judge the implications. That’s particularly true if you have cardiomyopathy, because the distinction between the different causes of cardiomyopathy is so important that other tests (such as a thallium stress test or an angiogram) may be needed even if your EBCT scan is normal or only mildly abnormal.

If you don’t have cardiomyopathy or any other symptoms of heart disease but do have an EBCT scan that indicates plaque buildup, it will be hard for your physician to determine whether you should have further testing — there just isn’t enough research on this topic. However, many researchers suspect that additional testing is worthwhile for people with a calcium score that’s higher than average, that is, above 400 to 500.

At present, EBCT is not the Holy Grail of diagnosis. I am hopeful that ongoing studies will tell us who can benefit most from this promising test. But for now, I can’t recommend it as a routine screen for clogged arteries, or as a substitute for established forms of testing in people with cardiovascular symptoms. Noninvasive methods that we have now, such as thallium stress tests, regular treadmill tests, and the simple analysis of risk factors, will continue to serve us well as we look for the subtle signs of coronary artery disease.

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