HOUSTON – Over the past 5 years there has been no growth in bilateral internal mammary artery use among Medicare beneficiaries, and the frequency of bilateral internal mammary artery use during coronary artery bypass grafting remained low, according to a large observational analysis.
“Despite a growing evidence base supporting bilateral internal mammary artery use with regard to long-term survival and freedom from repeat revascularization, rates of bilateral internal mammary artery [BIMA] use remain low, with no evidence of growth,” Alexander Iribarne, MD, said during an interview at the annual meeting of the Society of Thoracic Surgeons. “Therefore, there is significant opportunity for adoption of bilateral internal mammary artery grafting in the United States.”
The most recent report of CABG trends in the United States published from the STS database showed that in 2009, fewer than 5% of patients who underwent CABG received a BIMA (J Thorac Cardiovasc Surg. 2012 Feb;143[2]:273-81). In an effort to characterize the adoption rate and regional variation of BIMA use in the United States, Dr. Iribarne, director of cardiac surgical research in the section of cardiac surgery at Dartmouth-Hitchcock Medical Center, Lebanon, N.H., and his associates examined records from nearly 150 million Medicare beneficiaries from 2009-2014. “This work is unique in that we not only looked at trends in rates of usage but also how this varied by geographic location,” he said.
Dr. Alexander Iribarne
“I was surprised to find that despite the growing literature supporting BIMA use, there was no growth in rates of usage over the 5-year study period, with rates remaining low,” Dr. Iribarne said. “I was also surprised to see that there was significant regional variation in use that appeared to correlate, in part, with overall CABG volume, although the moderate correlation coefficient indicates that additional factors beyond CABG volume are involved.”
A key limitation of the study, he said, was that its patients were aged 65 and older. Dr. Iribarne disclosed that he receives grant funding from the American Association for Thoracic Surgery Graham Foundation and the Dartmouth SYNERGY Clinical and Translational Science Institute.