High-Tech Scans Spot Heart Blockages

Nov. 5, 2007 (Orlando, Fla.) -- High-tech heart scans may help some people to avoid invasive, and sometimes unnecessary, procedures to check for blockages in the coronary arteries, researchers say.

In a new study, the sophisticated 64-slice computed tomography coronary angiography scan proved nearly as accurate as standard cardiac catheterization at spotting blocked coronary arteries.

The scans won't replace cardiac catheterization, also known as coronary angiography, but they can help doctors rule out people who can skip the more invasive procedure, says researcher Julie Miller, MD, assistant professor of medicine at Johns Hopkins Hospital in Baltimore.

Studies suggest that as many as one in four of the 1.3 million cardiac catheterization procedures performed each year in the U.S. may be unnecessary, she says.

CT Heart Scans Quick, Noninvasive

Early detection of blockages is critical to preempting a heart attack, allowing time for drug therapy, angioplasty, or heart bypass surgery to be used to keep arteries open.

Cardiac catheterization is the gold standard for evaluating blood vessel obstructions. In the procedure, contrast material -- a substance that makes it easier to see in an X-ray -- is injected through the catheter. Then an X-ray is taken of the area to look for blockages.

While it sounds like a mouthful, the 64-slice computed tomography coronary angiography scan is rapidly joining the health lexicon. It's a type of CT scan that gives doctors a detailed look at the coronary arteries, which supply blood to heart muscle.

The technique is quick, producing pictures within five to 10 seconds, compared with 30 to 45 minutes for catheterization, Miller says. It's noninvasive, with potentially less risk and discomfort than catheterization, which often requires sedatives and sometimes a night in the hospital.

The potential complications of catheterization, while extremely rare, include infection, heart attack, and stroke, Miller says.

CT Heart Scans Relatively Accurate

The study involved 291 men and women over age 40 who were scheduled to have catheterization to check for blocked arteries. Each underwent a 64-CT scan prior to catheterization.

The findings were presented at the American Heart Association's Scientific Sessions 2007.

After a year, Miller says that in spotting blockages, the results of the heart scans matched up with the catheterization results 90% percent of the time.

However, the CT scans were not very good at locating exactly which vessel was blocked, the study showed.