Heart Test Questions
New Guidelines For Controversial Cardiac Test Spur Debate
The American Heart Association and the American College of Cardiology say the cardiac test known as electron-beam computed tomography, shown here, has fewer benefits than the manufacturer and some healthcare providers believe. (Imatron, Inc.)
By Robin Eisner
N E W Y O R K, June 30 — Every year approximately 300,000 Americans undergo a high-tech procedure that looks at the level of calcification in their coronary arteries to get a better sense of their risk of having a heart attack. Quick CAT scans are often misleading.
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Called “electron-beam computed tomography,” 120 free-standing diagnostic and medical centers throughout the world offer the approximately 8-minute diagnostic test for $500. The method, similar to other non-invasive body- scanning technologies that employ x-rays, can detect these calcium deposits. The mineral buildup is associated with atherosclerosis — or hardening of the arteries — and a possible risk of a future heart attack.
The patient will pay out of pocket if he or she walks into these facilities without a doctor’s referral. An insurer might pick up the costs if a doctor has referred a patient who is experiencing symptoms, such as chest pains.
New Guidelines Limit Usage
The increasingly popular and somewhat controversial method, though, is coming under fire from the American Heart Association and the American College of Cardiology for its use in what they are calling unwarranted circumstances. After a committee from the two groups analyzed published data from 1988 through 1999 and information from other sources on the method, the two organizations today are clarifying when they think the test should be used.
Concerned the test is being used too frequently by the worried well because of persuasive advertising by these centers, the committee says it does not recommend the method in asymptomatic people without multiple risk factors, such as high blood pressure, use of cigarettes, high cholesterol levels, a history of heart disease in the family, obesity or diabetes.
The groups cite a 43 percent false positive rate for the test and thousands of dollars of unnecessary follow-up tests as the reasons. “Some physicians are suggesting electron-beam computed tomography be done on every person in the country over age 20,” says Dr. Robert A. O’Rourke, writing group chair, of the University of Texas Health Science Center, in San Antonio. “They are even advertising to the lay public.”
Test Would Help Some
But the two organizations acknowledge the method has some benefit for certain people, particularly those with an intermediate risk of developing coronary artery disease, says Dr. Sidney Smith, a past president of the American Heart Association.
Cardiologists characterize patients’ risk of developing coronary artery disease based on a variety of risk factors, such as blood pressure, family history, cholesterol levels and give the individual either a high, intermediate or low risk score.
Moderate risk individuals, Smith explains, might benefit from the test because it would enable doctors to distinguish those patients who had a high calcium count and might need more aggressive cholesterol-lowering or blood pressure-decreasing drug therapy, from those who only needed lifestyle modification treatments.
High risk individuals, Smith says, would not benefit from taking the test because the treatment would be drug therapy and further analysis with either stress testing or angiography — better tools to determine blocked blood vessels.
Smith says a trial sponsored by the National Heart, Lung and Blood Institute called the Multiethnic Study of Atherosclerosis, is currently testing the benefits of electron-beam computed tomography in asymptomatic people. The results should be available in 2004, he says.
Company and Practitioners Disagree
But spokespeople for Imatron, Inc., of south San Francisco, the manufacturer of the $1.8 million piece of equipment, a leading expert in the use of the machine and health care practitioners disagree with the new policy.
Dr. John A. Rumberger, director of the Ohio Heart free standing electron-beam computed tomography screening facility, in Columbus, challenges the new position on all counts, saying the non-invasive method can help distinguish treatment in all types of individuals. Rumberger, an expert in the use of the method and author of more than 100 peer-reviewed articles about it, was on the committee but quit because he felt its members were biased.
“Of people who have high cholesterol and are deemed high risk, 25 percent actually are low risk,” he says. “Likewise for people who have low cholesterol and are deemed low risk — 25 percent actually are high risk.” Rumberger says the method allows doctors to look inside all these patients’ blood vessels and determine who has calcification and therefore who has real disease.
Imatron Clinical Sciences director David King adds that not all high-risk people need drugs, as Smith suggests, and the test can help separate out who should have less aggressive treatment.
U.S. physicians currently are referring high- and moderate-risk patients for the test, according to David Sprouse, vice president for Lifetest Cardiac Imaging, of Nashville, Tenn., which has six facilities with these machines throughout the country that do 15,000 scans a year.
Patients who may not have any risk also are walking in off the street to these centers. “Patients come to us if they have a family member who just had a heart attack,” explains Maria Infante, a registered nurse at the Cardiology Prevention Center at Hackensack University Medical Center, in New Jersey. She feels they should have the right to do so.
“Why shouldn’t a patient be able to find out their risk of coronary artery disease by this test,” asks Infante. “If they have no calcification we can send them on their way and educate them about diet and exercise. For those who are positive we send the information to the referring physician for further tests.”
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