February 4, 2011 (San Diego, California) — Results from 22 years of cases by surgeons in Melbourne, Australia, suggest that more cardiac surgeons should learn how to use the right internal thoracic artery (RITA) as a bypass conduit.
Here at the Society of Thoracic Surgeons (STS) 2011 Annual Meeting, Dr James Tatoulis (University of Melbourne, Australia) presented data from his center's experience with coronary bypass surgery from 1986 to 2008. Registry data show that only about 5% of bypass procedures in the US and 11% in Australia use the RITA, also known as the right internal mammary artery graft, even though it is biologically identical to the left internal thoracic artery (LITA), which has been consistently shown to be the best conduit for a bypass procedure, Tatoulis explained.
"A number of us have been doing this since the early 80s, but because it takes extra time to take out the second [right] mammary, it's been neglected. But it seems a shame--for the effort of putting in an extra 30 or 40 minutes--to deny patients," Tatoulis told heartwire . In addition to the extra time it takes to harvest and graft the RITA, "there's a feeling that there might be more complications with wound healing and also some insecurities on how to use it." The purpose of this study is to show that RITA grafts can be as reliable and durable as the more common LITA grafts and thereby "stimulate more confidence in its use," Tatoulis said.
In the study presented by Tatoulis, there were 5766 bypass patients who received a RITA graft, almost always as part of a bilateral bypass procedure in which both the LITA and RITA were grafted to restore blood flow to the coronaries. The study included a total of 7780 coronary conduits, including 991 RITAs examined at an average of 100 months after the surgery.
Ten-year survival of patients with RITA and LITA for triple-vessel coronary disease was 89%. Overall, 90% of the RITAs were still patent (<80% stenosis) after 10 years, identical to the 10-year patency rate for LITA grafts and significantly better than the patency rates for radial artery or saphenous vein grafts, Tatoulis said. The long-term patency rates were best for RITA grafts to the left anterior descending artery (95% at 10 years, 90% at 15 years) and lowest for RITA grafts to the right coronary artery (85%).
Commenting on the study at the STS meeting, Dr Bruce Lytle (Cleveland Clinic, OH) said, "Unfortunately, the superiority of bilateral internal thoracic artery grafting is, to use a current phrase, an inconvenient truth. The operation takes longer and is harder to do . . . and it's harder to teach."
He added that there is no "external impetus" for surgeons to use this technique, since they are not reimbursed more for it and RITA grafting is not recognized as an indicator of quality by cardiac surgeons' own professional quality standards. "We haven't as a group chosen to elevate our pursuit of this operation, [even though] everyone in this room believes, in their heart of hearts, that this is the best operation to perform in terms of long-term survival and graft patency," Lytle said. "Now that we have this and other information [on RITA graft outcomes] in hand, I think how our use of this strategy pans out over the next few years will say something about our attention to evidence-based surgery and our character."
Tatoulis told heartwire that his group is about halfway through a 10-year, 1000-patient randomized trial comparing RITA with radial artery bypass grafts in patients under 65. Also, the Arterial Revascularisation Trial (ART) has randomized 3102 patients at 28 hospitals to single internal thoracic arterial grafting or bilateral internal thoracic arterial grafting. The primary end point is 10-year survival. One-year data from ART showed similar results in the two groups, but the bilateral graft patients were slightly more likely to need sternal-wound reconstruction.
Tatoulis and Lytle reported no conflicts of interest.
Heartwire from Medscape © 2011 Medscape, LLC
Cite this: Right Internal Thoracic Artery Should Be Used More Often - Medscape - Feb 04, 2011.