Melbourne surgeons show long-term benefits of radial artery harvest in CABG

Interventional cardiology

By Michael Woodhead

6 Dec 2018

Prof Alistair Royse

Victorian cardiac surgeons who pioneered harvesting of forearm arteries for coronary bypass surgery have shown that the practice is safe and does not compromise the function or blood flow of the affected arm even after 20 years.

Since the 1990s Professor Alistair Royse and colleagues at the Royal Melbourne Hospital and University of Melbourne have been using the radial artery in CABG procedures in preference to the more commonly used saphenous-vein grafts

The radial artery grafts have proven more durable and have a good prognosis in CABG, whereas about half of veins used in heart bypasses becoming completely blocked within 10 years of surgery.

However, most cardiac surgeons globally have been reluctant to adopt the artery-only bypass method. In around 95% of bypass operations, the practice is still to use saphenous-vein grafts, in combination with one of the chest wall arteries.

Professor Royse says he now hopes new results in favour of artery bypasses will drive a change in global practice.

In a study published in the Journal of the American College of Cardiology (JACC), Professor Royse and colleagues have shown that arms and hands can easily cope without the radial artery because the parallel “ulnar” forearm artery can cope on its own.

The follow-up study of 86 patients who had their radial arteries harvested between 12 and 22 years ago found blood flow to the arm and hand was unaffected, whether at rest and or during exercise.

“Our report supports the long-term safety of RA use as an arterial conduit for coronary surgery,” they wrote.

A second key finding was that dynamic increases in blood flow with exercise were preserved and not different between the two forearms.

“This provides assurance that the harvested forearm and hand may be used in vigorous daily activities without restriction,” wrote Professor Royse and colleagues.

In addition, they found no evidence of accelerated atheroma formation in the ulnar artery as a result of  chronically increased blood flow.

“What was interesting and exciting was how the ulnar artery adapts to be able to compensate for the removal of the radial artery,” said University of Melbourne research student Megan O’Donnell, who conducted the study with Professor Royse.

Professor Royse has also published research showing that people with artery-only bypasses have better survival rates.

This includes an analysis of 51 113 heart bypass patients from Australia and New Zealand that has now been published in the European Journal of Cardio-Thoracic Surgery and a separate study of 880 Royal Melbourne patients going back to 1996 published in the JACC.

Professor Royse said he is surprised the medical profession internationally is still yet to embrace artery-only bypasses. He believes this is partly due to reasonable caution about any new medical procedures, but also to a lack of experience in harvesting the radial artery.

“Change isn’t just about following the scientific evidence,” he said. “There are human factors at work that are sometimes just as important or more so. But maybe now we are approaching a seismic shift where the evidence is just so substantial that people will start changing.”

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