New CT Scans Challenge Routine Angiograms

Angiograms—also known as arteriograms—are the primary tests used to detect blockages in the arteries of the heart. Using a catheter that starts in the groin, a wire goes through blood vessels into the heart and when dye is injected, any artery blockers can then be seen in an X-ray. New research says there may be a safer, noninvasive way to use CT (computed tomography) scans instead of the more invasive angiogram.

Published in the New England Journal of Medicine (NEJM) this week researchers in Baltimore found a way to use a CT machine to take three-dimensional pictures of the heart. The American Heart Association records that with over 1.2 million angiograms performed in the United States every year, 1 to 2 percent of them endure complications. This new scanning procedure could prove to be safer than the heavy risks involved in invasive angiograms like blood vessel damage, the possibility of blood loss, and fatality. Statistics show that around 25 patients die every year from complications involved in angiography.

Lead author of the study and interventional cardiologist from Johns Hopkins University School of Medicine  Dr. Julie Miller says that the fatalities come as a surprise to some because 20 to 30 percent of the angiograms performed give a false negative, resulting in needless risk for thousands of people.

CT scans are seen as a safer alternative because there aren’t as many complications involved in the quick outpatient procedure. After inserting an IV, patients lie on a table and are moved slowly under the scanner as a diluted dye flows through the veins making the affected body parts easier to see in the pictures, resulting in an easier process for viewing tumors, cysts, and complications unable to be seen in a normal X-ray.

Miller’s team collaborated with nine other hospitals throughout the world and watched 291 patients with a high risk of coronary artery disease who would have normally undergone a procedural angiogram. The average age of the patients was 59 and the majority of them were male.

After the patients went through both procedures—the CT scan was completed before the angiogram—physicians and researchers compared results side by side. Funded partially by grants from the National Institutes of Health, results were varied.

Of the results, CT scans showed a high percentage of accuracy against the popular angiogram, 85 percent of the patients who had large blockages were shown in the CT while 90 percent of the patients who did not have blockages were able to be determined by the noninvasive method.

Two patients endured a reaction to the dye from the CT and another person died as a result of the angiogram, because no trials are free of complications. As with every new procedure, there are always more tests that need to be done and further research is still on the horizon to make sure new high-tech 64 slice CT scanners are worthwhile for doctors and patients.

A big concern is how cost effective these scans will be if they do not completely take the place of angiograms. The manufacturers (who partially funded the research) Toshiba Medical Systems said in a statement that the scanners, “cannot replace conventional coronary angiography at present,” yet over 5,000 units have been sold with a 2 million dollar price tag. Besides leaving many wondering about the overall effectiveness of this new technology, the cost to medical providers, insurance coverage, and patient out-of-pocket expense, the biggest concern still is radiation.

CT scans, although more helpful for viewing your insides than a normal X-ray or an ultrasound, carry with them a heavy exposure to radiation that can be harmful in the long run. University of California San Francisco School of Medicine professor Dr. Rita Redberg, who authored an accompanying article to the main study, thinks we may have jumped the gun on using CT scans when the outcome data hasn’t been collected, "I think it's being used without clear data of any benefit for the patient," says Redberg, who continues to worry about radiation exposure to the heart which is a magnification of a regular chest X-ray by 500 times, “Importantly, but unfortunately, we don't know what the radiation risks are….It's been estimated that we're going to see tens of thousands of additional cancers in the U.S. population because of our increased use of CT scans."

Although there are many concerns with the heart CT scans, especially the benefits—if any—from this new technology, all medicine comes with pros and cons. Until more research is conducted and more test results are in, we can only hope that this noninvasive approach to angiography will help, not harm the future of patients with cardiac conditions.