High-Tech Scans Spot Heart Blockages
Sophisticated CT Scans May Help Avoid Unnecessary Procedures
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.
How Will Doctors Use CT Heart Scans?
"This is a very positive study in the sense it showed the effectiveness of the 64-slice CT to identify people with coronary artery disease," Timothy Gardner, MD, tells WebMD. Gardner is an American Heart Association spokesman and a heart surgeon at Christiana Care Health Services in Wilmington, Del.
"The question that still remains is how it fit into the diagnostic workup of the patient without adding an additional test along the way," he says.
Miller tells WebMD that the new scanners, which are four times faster than traditional 16-slice CT scans, may be a good alternative to exercise stress tests to look for coronary artery disease in some patients.
Exercise stress testing generally cannot safely be performed on a frail, elderly person, she says.
Also, "this can be an additive test for people who have equivocal results on a stress test but whose doctors don't think there is anything wrong. Right now, they are referred for catheterization, but the CT scan could help avoid that," Miller says.
CT Heart Scans' Limits
CT scans are not for everybody. They fail to produce good images in people with a lot of calcium deposits in their artery plaque, Gardner says. Like sludge in a drain, the calcium interferes with a clear picture.
In fact, people with a lot of calcium deposits -- who accounted for about one in four of people originally recruited -- were excluded from the study.
Raymond J. Gibbons, MD, a past American Heart Association president and the Arthur and Gladys D. Gray professor of medicine at the Mayo Clinic in Rochester, Minn., tells WebMD that he's also concerned about cancer risks.