High-Tech Images Can Reveal Stent Status

The technology to see if it is open or blocked could one day spare some patients invasive tests, study suggests

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By
HealthDay Reporter

TUESDAY, May 29, 2007 (HealthDay News) -- Newer multislice computed tomography scanners can yield images that show whether a heart patient's stent has become blocked.

This technology potentially eliminates the need for inserting a catheter to perform invasive angiography, Dutch cardiologists report.

"Eventually, the goal is to avoid invasive angiography," said Dr. Jeroen J. Bax, professor of cardiology at Leiden University Medical Center, a member of the team reporting the study findings. "We are not there yet, but it is moving in the right direction."

But the technique is not likely to be available widely in the near future, because it requires intensive training, Bax said. "What we have here is not readily communicable to the wider community," he said.

And the complexity of heart disease and its treatment in many patients will inevitably limit the use of the method, one U.S. expert said.

The Dutch cardiologists used a multislice computed tomography scanner that provides a 64-slice image of the heart. They tested the prowess of the machine on 182 patients who had been given stents -- tiny mesh tubes -- to prop open a total of 192 arteries and who were scheduled to have angiography six months later, either as a routine follow-up or because of symptoms suggesting that a stent had narrowed or closed.

All underwent multislice computed tomography scans (MSCT), followed by invasive angiography a few days later. Angiography showed significant narrowing or closure of 20 stents, and MSCT correctly detected 19 of them. MSCT also correctly showed no significant problem in 147 of the 158 stents given a clean bill of health by angiography -- a success rate of 99 percent.

The study is published in the June 5 issue of the Journal of the American College of Cardiology.

"The implication of this finding is that if a narrowing is not detected, it is unlikely to be present, which potentially could avoid unnecessary catheterizations," said Dr. Gilbert Raff, director of the Ministrelli Center for Advanced Cardiovascular Imaging at William Beaumont Hospital in Royal Oak, Mich.

"But my own feeling is that if you have a patient with a stent and want to know whether the stent is open, the first step should be a stress test," he said.

Multislice computed tomography scans might be good at showing whether an individual stent is open or blocked, "but most patients who have stents have cardiovascular disease in a number of locations," Raff said. "If they present with symptoms, a stress test can give you a pretty good idea of whether a stent is responsible."

The MSCT technique could be valuable in some cases, Raff said. "My conclusion was that if the patient had a single stent in a major branch of an artery, it would be useful," he said. "But a typical patient who gets stents has four or five stents in different areas. If the patient presents with chest pain or back pain, I would say get a stress test first. If the stress test was normal, I'm not sure MSCT would be the thing to do. If the stress test was abnormal, then you could do catheterization or MSCT. If it were single-vessel disease, that might be helpful."

Multislice computed tomography scans might also be useful in cases where the problem was more subtle, with narrowing of the stent, Raff said. The Dutch cardiologists aren't the only ones working to advance the technique, he noted; a group in Japan has reported similar results.

"That is where the technology is pushing the edge," Raff said. "But if the problem is in many vessels, not just one, this is not the technique of choice."

More information

To learn more about computed tomography, visit the U.S. National Library of Medicine.

SOURCES: Jeroen J. Bax, M.D., professor of cardiology, Leiden University Medical Center, the Netherlands; Gilbert Raff, M.D., director, Ministrelli Center for Advanced Cardiovascular Imaging, William Beaumont Hospital, Royal Oak, Mich.; June 5, 2007, Journal of the American College of Cardiology

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