In long-term follow-up, patients undergoing multiarterial coronary artery bypass grafting (CABG) with either a bilateral internal thoracic artery approach or a combination approach involving a single internal thoracic artery plus radial artery had similar survival at 15 years, suggesting no clear survival advantage for either strategy, according to a new study.

Results also showed that the use of both multiarterial grafting strategies have been on the rise in the US over the past decade.

The findings were presented recently by Thomas Schwann, MD, MBA, regional chief of cardiac surgery at Corewell Health East in Royal Oak, Michigan, at the Society of Thoracic Surgeons (STS) 2026 Annual Meeting.

The study involved adult patients aged younger than 90 years from the STS Adult Cardiac Surgery Database (2008-2023), a population reflective of the practice patterns of most cardiac surgeons. Patients underwent primary, nonemergency, isolated CABG with bilateral internal thoracic artery or radial artery plus one internal thoracic artery grafts.

Outcome Measures

Overall survival at 15 years and time-segmented landmark survival (0-5, 5-10, and 10-15 years) served as outcome measures. The researchers included additional analysis in several key patient subgroups. They determined long-term survival via linking the STS Adult Cardiac Surgery Database to the National Death Index and the Center for Medicare and Medicaid Database.

The study population included 81,719 patients who underwent CABG with the combination radial artery and single internal thoracic artery strategy (age, 61.8 years; 84% men) and 76,496 who received bilateral internal thoracic artery grafts (age, 61.2 years; 85% men).

The frequency of multiarterial CABG in the US increased from 9% to > 16% over the study period, largely due to an increased use of single internal thoracic artery plus radial artery grafts and modest growth in the use of bilateral internal thoracic artery grafts.

‘Uniformly Excellent’

Before risk adjustment, both study groups had similar rates of three-vessel disease, prior percutaneous intervention, ejection fraction, and STS predicted risk for operative mortality. However, insulin dependence and BMI were lower in patients receiving bilateral internal thoracic artery grafts.

The researchers reported that unadjusted, observed survival was “uniformly excellent” in both groups but incrementally better in the bilateral internal thoracic artery group. Moreover, a third arterial conduit, bilateral internal thoracic artery plus radial artery, was associated with the best survival rate.

At 15 years, survival was equivalent with both the bilateral internal artery and single internal artery plus radial artery strategies (adjusted hazard ratio, 1.00; 95% CI, 0.97-1.02). An improved survival in younger patients in the bilateral internal thoracic artery group was offset by better survival in patients aged 70 years or older in the single internal thoracic artery plus radial artery group.

More Is Better

Furthermore, in the landmark analyses, survival from 0 to 5 years was better with the single internal thoracic artery plus radial artery strategy, whereas survival with the bilateral internal thoracic artery strategy trended better after 10 years.

The inclusion of additional arterial conduits, such as a bilateral internal thoracic artery plus a radial artery strategy, yielded an 11%-12% improved 15-year survival compared with both the single internal thoracic artery plus radial artery and bilateral internal thoracic artery strategies.

“The message is that bilateral internal thoracic artery and radial are equivalent strategies in terms of long-term survival up to 15 years postoperatively,” Schwann, told Medscape Medical News.

“But the penultimate message is that the more arterial bypass one utilizes, the better the long-term outcomes,” he said. “These results should encourage folks to potentially utilize both bilateral internal thoracic arteries and radial in appropriately selected patients for optimal long-term survival outcomes.”

‘Major Advance’

James Tatoulis, MBBS, MS, MD, professor of cardiothoracic surgery in The University of Melbourne in Melbourne, Australia, said similar results have been reported from individual institutions in recent years.

However, he said having these nationwide data are a major advance. Tatoulis was not involved in the study.

The perioperative results were excellent with in-hospital mortality of only 1% and a stroke rate of 1%, and only 33% of patients required any blood products, Tatoulis said.

“These are excellent operative outcomes and highlight that these multiarterial grafting procedures can be performed by many surgeons around the United States (and the world), with perioperative results equivalent to the standard left internal mammary artery and vein graft operations.”

Quality Improvement

Given that only about 16% of patients undergo multiarterial grafting, Schwann said, there is a potential opportunity for significant quality improvement for the specialty. That includes the possibility of transforming the current practice patterns from highly selective to more routine use of multiarterial grafting, he said.

Schwann did caution that appropriate surgical and institutional expertise is necessary to ensure patients receive the best benefit of multiarterial grafting.

“There is probably a learning curve that needs to be overcome,” he said. “Our professional society should strive to offer surgeons who are in practice and training appropriate opportunities to develop those skillsets to carry out multiarterial grafting in a routine rather than selective fashion.”

Tatoulis added that the results should reassure and provide confidence to surgeons that embarking on these slightly more unusual and complex procedures will produce excellent outcomes.

“By performing these surgeries, the average patient will have their life prolonged by a number of years, and they will be at less risk for interim major adverse cardiac events during the rest of their life,” Tatoulis said.

As a result, he said, there is a potential for the frequency of these operations to increase to 30%-50% in the US for patients with multiarterial disease. That would mirror the usage rates in other jurisdictions, including Australia, many Asian countries, and some of Europe, he said.

Schwann and Tatoulis reported having no relevant financial relationships.

Brian Ellis is a freelance writer and editor who lives in Southwest Virginia.