NEW YORK (Reuters Health) - More patients could benefit from x-ray scans of their hearts, according to new advice put forth in a report from several medical societies.
But the expanded criteria may be more geared to benefitting medical professionals than patients, according to some experts who say the scans are little more than pretty pictures with a big price tag -- and potentially serious side effects.
Computerized tomography, or CT, scans can help doctors determine whether a patient has heart disease. For instance, they can reveal problems in heart valves or cholesterol plaques that prevent the heart from working properly by blocking its blood supply.
While other tests can give doctors much of the same information, the authors of the new report hope CT scans will now be used in many cases instead.
“There have been significant technological advances such as the speed of the scan as well as lower radiation exposure,” said Dr. Allen J. Taylor, a cardiologist at Georgetown University in Washington, D.C.
To draft updated criteria for deciding when to use CT scans to diagnose heart problems, Taylor, a fellow of the American College of Cardiologists, chaired a group of cardiologists and radiologists from several medical societies.
The group evaluated 93 different scenarios and determined when a scan would and wouldn’t be appropriate. Compared to an earlier report from 2006, the criteria now cover more scenarios and put more patients into the “appropriate” category.
In the new report, eight scenarios have shifted from either “inappropriate” or “uncertain” regarding the use of CT to “appropriate,” while none moved the other way.
For instance, patients at low risk of heart disease are now considered suitable candidates for CT scans if they experience symptoms -- like chest pain and shortness of breath -- that typically accompany a diseased heart.
Scans to detect calcium deposits -- a component of cholesterol plaques -- may be appropriate even when patients report no symptoms.
“That moves calcium scanning into the mainstream,” Taylor told Reuters Health.
“Doing this is really increasing emphasis on quality and getting the most for the healthcare dollar,” he added. “The hope is that payers adopt it.”
But CT scans carry risks that weren’t emphasized in the report, which appears in the Journal of the American College of Cardiology.
For instance, they expose patients to significant radiation, which may increase cancer risks, said Dr. Rita F. Redberg, a cardiologist at the University of California, San Francisco, who was not involved in the work.
And the dyes that are sometimes used to enhance contrast in the pictures can damage the kidneys.
“Right now we don’t have any data showing that cardiac CT is as good as or better than other tests we have,” Redberg said.
Such tests include treadmill stress tests, ultrasound imaging and radionuclide imaging. Only the last exposes patients to radiation.
Redberg said CT scans for heart disease had become exceedingly popular over the past few years, with hundreds of thousands of them done every year.
CT scans may cost anywhere between a few hundred dollars to a couple of thousand. But in Redberg’s view, for patients who don’t have congenital heart defects, they are little more than “pretty pictures.”
“A test cannot predict whether or not you are going to have a heart attack, and it can’t prevent getting one,” she said. “You get more false information than you get real information.”
She said she usually counsels patients mostly based on known risk factors such as diabetes and obesity. In those cases, she may prescribe drugs to lower blood pressure and cholesterol levels.
But first and foremost, she recommends eating a heart-healthy diet, getting regular exercise and not smoking.
“Those things will prevent you from having a heart attack,” she told Reuters Health.
Dr. Patrick G. O’Malley, a general internist at the Uniformed Services University in Bethesda, Maryland, said the new criteria might increase overtesting.
“I think there is a risk that people will confuse appropriateness with evidence-based,” he said. “In general, these kinds of criteria tend to get misinterpreted.”
He said the writing group consisted of people with vested interests in the technology because they use it every day.
“They didn’t include people who are not involved in this research,” he told Reuters Health. “They didn’t include a patient perspective.”
SOURCE: link.reuters.com/mec47m Journal of the American College of Cardiology, online October 25, 2010.
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