May 25, 2005

A Better Way to Diagnose Heart Disease?

Computerized X-rays give clear pictures of coronary arteries

HealthDay News -- New high-tech computerized X-ray scans may help heart patients avoid invasive tests to determine whether they have serious cardiovascular disease, German researchers report.

The technique, called multi-slice computerized technology (MSCT), sends an X-ray beam spinning around the body to produce multiple images, or slices, of the coronary arteries.

In a trial including 103 patients suspected of having severe narrowing of cardiac arteries, MSCT proved just as effective as invasive coronary angiography -- the current standard test.

Cardiologists at University Hospital in Ulm, Germany, report the findings in the May 25 issue of the Journal of the American Medical Association.

Still, a number of questions both medical and economic must be answered before the technology becomes more widely available in the United States, American experts contend.

The medical issues involved include the relatively large dose of radiation needed for MSCT, which is "two to three times the dose typically administered during a diagnostic invasive angiogram," according to an accompanying editorial by Dr. Mario J. Garcia, chief of echocardiography at the Cleveland Clinic Foundation.

The new study adds important data confirming the results of previous trials, Garcia said. "This is a larger study in which the patients were not handpicked, and the statistics are very strong," he noted.

However, Garcia wrote in his editorial that "it is not yet clear how MSCT coronary angiography should be integrated in the clinical practice. Should it be used as a first test for the evaluation of chest pain or as a complementary test in patients with equivocal stress test results? In either case, adequate patient selection will be critically important."

But Garcia also seemed very optimistic about the new technology.

"Until now, one of the difficulties in cardiology is that a lot of what we do involves a certain amount of guessing," he explained. "The only diagnostic tool we have with 100 percent certainty is cardiac catheterization. That is invasive and expensive, so it is reserved for people at higher risk."

"The new procedure will change that paradigm because it makes it much less expensive, and takes the examination from the hospital to outpatient centers. It can be done quickly, and the information is available in minutes with minimum risk," he said.

Dr. Frank J. Rybicki, director of the applied imaging science laboratory at Brigham and Women's Hospital in Boston, is an enthusiastic supporter of MSCT.

"It means a new opportunity to get coronary arteries evaluated without cardiac catheterization in a relatively safe manner," he said.

But Garcia and Rybicki agreed that MSCT is not yet widely available in the United States -- and may not be for some time.

"Right now, it is available at selected academic centers," Rybicki said. "We at Brigham and Women's feel we are leading the way, with one of the programs to do this on a routine basis. But there is an enormous growing U.S. movement to get it out of academic centers to private practice."

"It will take some time before physicians are trained to perform MSCT with high quality in community hospitals," Garcia said. "Right now, perhaps 10 to 20 centers can do it."

Money is an issue, as well, Rybicki said. A new billing code for the procedure was adopted by regulatory officials in the United States, and many health insurers are deciding whether or not they will pay for the technology, he explained.

"At a major academic center like ours, we can afford not to be paid for six months while the code is sorted out," he said. "But if I were in private practice, I would not do it for free until I was sure I would be paid for it."

More information

For more on heart disease prevention, head to the American Heart Association (www.heart.org ).