Radial Artery Grafts Set To Improve Long Term Survival

The use of the radial artery in coronary artery bypass graft (CABG) procedures is likely to improve long-term graft survival if early experience reported here during the 37th annual meeting of The Society of Thoracic Surgeons continues to hold.

Based on findings from over 2,000 coronary vein graft angiograms, investigators from the University of Melbourne, Australia, have previously shown that patency rates at ten years are only about 50 percent and at 13 years, graft survival is a disappointing 23 percent.

In an effort to improve long-term graft survival, Melbourne investigators began to explore the use of radial arteries as potential bypass conduits in the early nineties. Now, having used either single or bilateral radial artery grafts in over 6,600 patients undergoing CABG between 1995 and the year 2000, Australian investigators are reporting excellent early clinical and angiographic results in almost all grafts at two and more years follow-up.

“The surgical strategy involves the left internal thoracic artery (ITA) for everybody, bilateral ITAs for patients less than 65 years, and the radial artery as the main graft of choice,” Dr. James Tatoulis, chief of heart surgery, Royal Melbourne Hospital, Australia explained. Over 4,800 patients in their series received a single radial artery, while over 1,700 patients received bilateral radial artery grafts, Dr. Tatoulis added. The mean number of anastomoses per patient was 3.3.

Operative mortality in this large series of patients, mean age 65 years, 23 percent of whom were diabetic, was low at only 0.9 percent. Stroke occurred in only 1.4 percent of patients, and myocardial infarction in 0.8 percent.

Based on angiographic data obtained in a small subset of the series at a mean follow-up of 14.4 months, the group has achieved excellent overall patency rates, approaching 91 percent. Patency rates in grafts where the native coronary stenoses were less than 60 percent are lower, at 79 percent, Dr. Tatoulis added.

In contrast, when the native coronary stenosis are at 90 percent, patency rates were higher at 98 percent. Dr. Tatoulis noted that care must be taken when harvesting the radial arteries to avoid damaging surrounding nerves. In approximately 10 percent of patients, the radial arteries are also not suitable for grafting due to calcification and fibrosis.

However, once harvested, “the incisions heal beautifully” in most patients, he said, “and forearm morbidity is low.” In this series, for example, investigators documented only 21 forearm infections, and 14 forearm hematomas required draining. Fingertip ischemia was also observed in two patients. Furthermore and in contrast to the harvesting of sapphenous vein grafts, patients are able to ambulate rapidly when the radial arteries are used.

“The radial artery is 2.5 mm distally, 3 to 4 mm proximally, and 25 cm in length. It is also easy to handle and doesn’t kink,” Dr. Tatoulis said, adding in an interview with Doctors Guide:

“The use of the radial artery in this large series of patients allowed us to achieve total arterial revascularization in 87 percent of our patients and the operative mortality is low. ÄSinceÅ we already know that when you use one mammary graft, survival is better than when you have vein grafts, and when you use two arterial grafts, survival is better than if you have only one arterial graft, in the next five to 10 years, we are hoping to show that when you have three and four arterial grafts, survival is again going to be enhanced.”