EBT Myths and Misconceptions
There isn’t enough data available yet to justify screening large groups of asymptomatic individuals.
In excess of 1,000 articles have been published in medical journals attesting to the accuracy, reliability and predictive value of Coronary Artery Scanning using EBT. In excess of 100 prestigious medical centers including the Mayo Clinic, Johns Hopkins, Harvard (Deaconess), Stanford, Cedars-Sinai (Los Angeles), the University of Illinois, the Arizona Heart Institute, the University of Pennsylvania, the University of Pittsburgh, the Cooper Clinic (Dallas), the Baylor College of Medicine, George Washington University, St. Francis Hospital (Roslyn, NY), the University of Iowa, Edwards Cardiovascular Institute (Naperville, IL), Rush Presbyterian Hospital (Chicago), Walter Reed Army Medical Center (Washington, DC) and Mount Sinai Medical Center (Miami), have found the data sufficiently compelling to justify utilizing the Coronary Scan as a screening tool.
Every man over the age of 50 already has coronary calcium, so it doesn’t make any sense to scan them.
Every man over the age of 50 most certainly does not have coronary calcium. In asymptomatic men in the 55 – 59 age group, 32% (one in three) still has no detectable coronary calcium and another 43% have calcium scores below 80, also placing them into a lower risk group. ONLY 25% of asymptomatic men ages 55 – 59 have scores above 80 (moderate atherosclerosis with increased event risk) but only 8% have scores over 400 (extensive atherosclerosis with marked increased event risk). As one might expect, the recommendations for additional evaluation and therapy are quite different for each of these groups.
No one under the age of 40 has coronary calcium, so it doesn’t make any sense to scan them.
This is also untrue. While the vast majority of men under the age of 40 have little or no coronary calcium and finding individuals with scores above 400 is rare, 18% of 35 – 39 year old asymptomatic males already have calcium scores of 1 – 80 (early atherosclerosis but still low event risk) and another 2% have scores above 80, putting them into the higher risk group and making them targets for secondary prevention.
I don’t like this test because patients who have no coronary calcium then think they have a license to behave irresponsibly with respect to diet and exercise.
This is truly a silly argument. Why wouldn’t the same hold true for cholesterol testing? And what about AIDS testing? Do people go out and have high risk unprotected sex because they’ve had a negative AIDS test? The standard recommendation for a patient who has a negative coronary calcium scan is to continue to follow the common sense principles that the medical establishment has been preaching for years, i.e., low-fat diet, regular cardiovascular exercise program, smoking cessation and weight, cholesterol and blood pressure control. Following the established guidelines will increase the likelihood that the patient’s arteries will stay as clean as possible for as long as possible.
This test only measures calcified plaque, and we now know it’s the rupture of non-calcified plaque that causes most heart attacks.
That’s correct, but the amount of calcium is highly correlated with the amount of total plaque burden (hard and soft) in the patient. Calcified plaque accounts for approximately 20% of the total plaque burden. Therefore, the more calcified plaque that’s found in the Coronary Scan, the more undetectable soft plaque must be present, and the greater the risk for a coronary event.
This test doesn’t give you the percentage of narrowing of a coronary artery, so it will never replace the angiogram.
The Coronary Scan was not designed to replace the angiogram. It serves a totally different purpose in the prognostic process. The coronary scan is a quick, safe, accurate and relatively inexpensive procedure, which makes it ideal for screening asymptomatic individuals. The angiogram, on the other hand, is highly invasive, expensive, and carries the risks of heart attack, stroke, or even death. It is used to confirm the presence of late stage coronary disease and to provide the road map needed to perform surgery.
I think stress testing provides the physician with more information.
While stress testing maintains an important role in the diagnostic process for symptomatic individuals, it only detects coronary disease once heart function and/or blood flow has been impaired. This, of course, is quite late in the process to determine there is a problem, and leaves the patient and physician with fairly limited options. Coronary Scanning on the other hand, is capable of detecting and measuring coronary disease before an obstruction occurs, providing the patient and physician the opportunity to address the situation effectively in a non-surgical fashion. In an article published in the August 18, 2004 edition of the Journal of the American College of Cardiology, the authors found that 56 percent of patients who had negative stress MPS scan (an extremely sensitive nuclear stress test) still had a coronary calcium scan that revealed enough disease to be predictive of high long-term risk for heart attack or death, and therefore to warrant institution of aggressive therapy (lifestyle modification and prescription drugs).
I know a patient who had a perfectly clean Coronary Scan and still suffered a heart attack.
That, of course, is true. Unfortunately, no test in medicine is 100% accurate. However, the 95+% negative predictive value of this test (if you have no calcium, there’s less than a 2% chance that you have obstructive disease) is extraordinarily high and far better than any measure of accuracy for stress testing in any of its variations. In fact, we’ve known since 1989 that the majority of people destined to die suddenly will be able to pass a stress test shortly before their fatal event.
There are too many false positives. There are many patients who have positive Coronary Scans who then have perfectly normal stress tests or angiograms.
The first statement is totally inaccurate. There are no false positives. The finding of coronary calcium is always indicative of the presence of coronary atherosclerosis. The second part of this statement reflects a total misunderstanding of the purpose of the Coronary Scan, which is to find people who are building plaque in their arteries before heart function and/or blood flow is impaired (which could result in a positive stress test). Furthermore, this statement is often made by a physician who has performed an unnecessary stress test or cardiac catheterization on a patient. A positive EBT Coronary Scan does not necessarily mean that further testing is required. The patient’s physician must look at the coronary calcium score in the context of the patient’s entire medical profile before deciding whether further testing is indicated. Insofar as many physicians are still not familiar with the prognostic significance of the coronary calcium score, Advanced Body Scan of Newport has developed an ‘EBT Coronary Calcium Scoring Guide’ which can be accessed from our Physician’s Portal web page. Our physicians are also available to consult with any physician to answer questions about interpreting this test.
The results of this test wouldn’t really change the way I would approach a patient’s therapy. I’m going to encourage him to eat properly, exercise regularly, reduce his cholesterol and blood pressure, and stop smoking regardless of the results of the coronary scan.
While all patients should receive such encouragement, it’s important to face the following reality: at least 30% of all patients with coronary artery disease do not have any of the traditional, high risk factors mentioned above. Therefore; focusing only on established risk factors will not improve their condition at all. Their disease may be the result of a more obscure factor such as genetics, elevated Lp(a), LDL subclass pattern abnormality, elevated homocysteine level, unknown infectious agents, etc. Therefore, finding coronary calcium in an individual who does not have any traditional risk factors may lead to a more intensive search for and eventual treatment of the actual disease.
I’m already exercising my brains out, dieting and taking a statin, so what’s the point of getting a heart scan if there isn’t really much more I can do?
First of all, if this individual has never had a Calcium Score, they really don’t know if they have disease. Therefore, they don’t really know if they should be on a statin to begin with. If they have a scan and do have enough disease to warrant statin therapy and lifestyle modifications, the calcium score serves as an invaluable base line assessment that can be used to track the progression or cessation of the disease when compared to future scan results. Thereby gauging the success or failure of the statin/lifestyle regimen…the only non-invasive “gauge” in medicine.
My total cholesterol is 165, I feel fine, take good care of myself, see my doctor regularly and have never had any symptoms… so getting a scan is a waste of money.
Clinical research has proven that cholesterol alone is a very poor predictor of heart disease, i.e. an educated guess with the potential of being wrong 50% of the time. We now know that genetics play a far more significant role, and we must therefore rely on testing that looks for the presence of the disease itself. Waiting for symptoms is not wise considering the first indication of heart disease is generally a heart attack or death.
The peer-reviewed literature is decidedly mixed on the value of EBT heart scans.
This is untrue. There are hundreds, if not thousands, of articles that attest to EBT’s accuracy, reliability and predictive value. The case against EBT is typically based on the following 3 articles:
First and foremost is “Coronary Calcium Does Not Accurately Predict Near-Term Future Coronary Events in High-Risk Adults” by Detrano, et al, May 25, 1999, Circulation. The name of this paper alone should give one pause before using it to attack the validity of EBT testing. This underpowered study was performed on high risk patients (average age was 66, average BMI was 32, 3% had already had a heart attack, 21% were diabetic and 50% were hypertensive). No one has ever proposed that such a high-risk population should be screened. Screening EBT heart scans are recommended primarily for the intermediate, not high, risk individuals. Most interestingly, Dr. Detrano followed these subjects for an additional five years after publication of this article. In his follow-up paper, “Coronary Artery Calcium Score Combined With Framingham Score for Risk Prediction in Asymptomatic Individuals” published in J.A.M.A. on January 14, 2004 he concluded “These data support the hypothesis that high CACS can modify predicted risk obtained from FRS alone, especially among patients in the intermediate-risk category in whom clinical decision making is most uncertain.”
Second is the review article by Anthony Fiorino, M.D., published in Annals of Internal Medicine, May 15, 1998. The tenor of the article was that more published data was needed before one could draw any conclusions regarding the effectiveness of EBT heart scans. Such data has been published in abundance in the 7 years subsequent to the publication of this review article.
Third is “Impact of Electron Beam Tomography, With or Without Case Management, on Motivation, Behavioral Change and Cardiovascular Risk Profile” by O’Malley, et al, May 7, 2003, J.A.M.A.. This paper concluded that EBT scans did not motivate patients to make improvements to their controllable risk factors. Just as in the Detrano study cited above, this study population did not at all resemble the individuals currently being scanned throughout the United States. In this case, active-duty US Army personnel (average age 42) were ordered to report for scanning. Only 15% of them had any coronary calcium whatsoever. The average calcium score was 5.85. Why would anyone even expect that healthy, active young individuals would change their behavior based on a finding of no or minimal calcium in a scan that they did not request? It flies in the face of logic to assume that older, less fit individuals who are paying for the scan on their own and typically have higher scores would react in the same disinterested fashion to their coronary calcium findings.