MR angiography can see heart bypass grafts, look for blockage

January 21, 2002

DALLAS, - High-resolution magnetic resonance angiography (MRA) may offer a risk-free way to identify narrowed vein grafts after bypass surgery, according to a report in today's Circulation: Journal of the American Heart Association. High-resolution MRA provides clear 3-dimensional images of blood vessels. MRA accurately identifies blockage in vein grafts, as well as the extent of narrowing, researchers say.

"The high-resolution images were comparable to images obtained with X-ray angiography, which is the gold standard test for diagnosing blocked arteries and veins," says Ernst E. van der Wall, M.D., an author of the study and professor of cardiology at Leiden University Medical Center, Leiden, the Netherlands.

In bypass surgery, surgeons take a blood vessel from another part of the body and create a detour around the blocked part of a coronary artery. In the procedure, an artery may be detached from the chest wall and the open end attached to the coronary artery below the blocked area. Or, a piece of a long vein in the leg may be used. One end is sewn onto the large artery leaving the heart - the aorta. The other end of the vein is attached or "grafted" to the coronary artery below the blocked area.

The MRA technique in this study was used to look only at bypasses that had used the patient's leg vein.

"Recurrent chest pain after coronary artery bypass surgery is alarming for the patient and can pose a clinical dilemma for the physician: Should the patient undergo an invasive test, such as an angiography, to determine the cause of the pain, or is it better to follow a course of watchful waiting?" says van der Wall. MRA may provide the needed answers without the risk of invasive testing or the anxiety associated with waiting, he says.

Narrowed or blocked arteries and veins are caused by the buildup of a hard, fatty substance called plaque. This buildup of deposits on the inner surface of arteries and veins is called atherosclerosis. When blocked arteries are "bypassed," the disease may progress to the new vein grafts and can cause recurrent chest pain called angina.

"The beauty of MRA is that it is a non-invasive test," says van der Wall, whereas the traditional diagnostic test, coronary angiography, is invasive. He says coronary angiography is an excellent tool for diagnosing disease in coronary arteries and grafts, but it can be risky after surgery.

Patients who undergo coronary angiography have a thin catheter (tube) inserted in the groin, which is then carefully guided into the heart. Dye is released through this catheter and makes the arteries and grafts visible on an X-ray. While most patients undergo angiography with no ill effects, sometimes the catheter can tear a blood vessel or cause other complications.

With MRA there are no such risks, he says.

In the study, van der Wall's team used high-resolution MRA to assess the condition of 56 vein grafts in 38 patients who complained of recurrent chest pain after bypass surgery. The patients, whose mean age was 67, were already scheduled for standard angiography to determine the cause of the pain, but agreed to have MRA in addition to the standard treatment. Nineteen of the patients had MRA before X-ray angiography and 19 patients underwent MRA following standard angiography.

Eighteen grafts were found to be narrowed by 50 percent or more, while 11 grafts were at least 70 percent narrowed and six were completely blocked. Two observers who were blinded to the findings of the standard angiogram or the report of the other observer assessed the MRA scans.

When the graft was at least 50 percent narrowed, the diagnostic accuracy of high-resolution MRA compared to traditional angiography was 65 percent to 88 percent. When the vessel was narrowed by 70 percent or more, accuracy was 73 percent to 87 percent, and when the vein graft was completely blocked, the accuracy was 83 percent to 100 percent.

Since MRA technology is still developing, van der Wall says it is too soon to suggest that it can replace standard angiography, but he says it could be considered as a useful diagnostic adjunct. "Also, the technique costs about $500, which is about half the cost of standard angiography."

According to the American Heart Association's latest statistics, about 12.6 million Americans have coronary heart disease. In 1999 more than 570,000 heart bypass surgeries were performed in the United States.
-end-
Co-authors of the study include: Susan E. Langerak, M.Sc.; Hubert W. Vliegen, M.D.; Albert de Roos, M.D.; Aeilko H. Zwinderman, Ph.D.; J. Wouter Jukema, M.D.; Patrik Kunz, Ph.D., and Hildo J. Lamb, Ph.D.

CONTACT: For journal copies only, please call: 214-706-1396
For other information, call: Carole Bullock: 214-706-1279
Maggie Francis: 214-706-1397

American Heart Association

Related Pain Articles from Brightsurf:

Pain researchers get a common language to describe pain
Pain researchers around the world have agreed to classify pain in the mouth, jaw and face according to the same system.

It's not just a pain in the head -- facial pain can be a symptom of headaches too
A new study finds that up to 10% of people with headaches also have facial pain.

New opioid speeds up recovery without increasing pain sensitivity or risk of chronic pain
A new type of non-addictive opioid developed by researchers at Tulane University and the Southeast Louisiana Veterans Health Care System accelerates recovery time from pain compared to morphine without increasing pain sensitivity, according to a new study published in the Journal of Neuroinflammation.

The insular cortex processes pain and drives learning from pain
Neuroscientists at EPFL have discovered an area of the brain, the insular cortex, that processes painful experiences and thereby drives learning from aversive events.

Pain, pain go away: new tools improve students' experience of school-based vaccines
Researchers at the University of Toronto and The Hospital for Sick Children (SickKids) have teamed up with educators, public health practitioners and grade seven students in Ontario to develop and implement a new approach to delivering school-based vaccines that improves student experience.

Pain sensitization increases risk of persistent knee pain
Becoming more sensitive to pain, or pain sensitization, is an important risk factor for developing persistent knee pain in osteoarthritis (OA), according to a new study by researchers from the Université de Montréal (UdeM) School of Rehabilitation and Hôpital Maisonneuve Rosemont Research Centre (CRHMR) in collaboration with researchers at Boston University School of Medicine (BUSM).

Becoming more sensitive to pain increases the risk of knee pain not going away
A new study by researchers in Montreal and Boston looks at the role that pain plays in osteoarthritis, a disease that affects over 300 million adults worldwide.

Pain disruption therapy treats source of chronic back pain
People with treatment-resistant back pain may get significant and lasting relief with dorsal root ganglion (DRG) stimulation therapy, an innovative treatment that short-circuits pain, suggests a study presented at the ANESTHESIOLOGY® 2018 annual meeting.

Sugar pills relieve pain for chronic pain patients
Someday doctors may prescribe sugar pills for certain chronic pain patients based on their brain anatomy and psychology.

Peripheral nerve block provides some with long-lasting pain relief for severe facial pain
A new study has shown that use of peripheral nerve blocks in the treatment of Trigeminal Neuralgia (TGN) may produce long-term pain relief.

Read More: Pain News and Pain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.