Long-term study supports broader use of multiple arterial grafting

Multiple arterial grafting (MAG) was associated with lower rates of death and revascularization over 15 years of follow-up than the standard form of coronary artery bypass grafting (CABG), according to a study in JAMA Cardiology.

MAG—when compared to the standard use of the left internal thoracic artery supplemented by saphenous vein grafts (LITA+SVG)—demonstrated risk reductions of 21 and 26 percent, respectively, for mortality and revascularization. And over a seven-year follow-up, incidence of MI and heart failure were cut by 37 and 21 percent, respectively, in the MAG group.

The study included more than 20,000 Canadian patients with triple-vessel or left-main disease who underwent CABG, 72.2 percent of whom received LITA+SVG and the rest MAG.

“The long-term benefits consistently observed across multiple outcomes and subgroups support the consideration of MAG for a broader spectrum of patients who are undergoing coronary artery bypass grafting in routine practice,” wrote lead author Aihua Pu, MSc, with Cardiac Services BC in Vancouver, British Columbia, and colleagues.

Patients receiving MAG in the study were younger, more likely to be male and healthier on average than those receiving LITA+SVG, but the researchers attempted to adjust for those factors.

The authors noted the median MAG use by surgeons during the study period (2000 to 2014) was 26.5 percent, and stayed near one-fourth of procedures for the final eight years of the trial.

Perceived fears of short-term risks have limited the use of MAG—by way of an additional arterial connection of the right internal thoracic artery or the radial artery—in patients requiring CABG. But in the JAMA study, short-term safety and revascularization outcomes were similar between the MAG group and the LITA+SVG group. MAG patients were at a significantly increased risk of sternal reconstruction at 180 days, but the absolute rate difference remained small (1.9 vs. 1.1 percent).

Lack of conclusive research about MAG’s long-term performance in various subgroups has also led to a reluctance to widely adopt the approach, the researchers said.

“Given the complex decision making in optimizing surgical strategy, identifying the appropriate candidates for MAG is crucial to maximize its long-term benefits,” they wrote. “Diabetes, obesity, COPD, older age, impaired ejection fraction, PVD, and renal disease have been associated with poor prognoses after CABG and low use of MAG.”

But Pu et al. found the long-term survival benefit of MAG and a reduced need for revascularization was present in these subgroups, with the exception of those with severely reduced ejection fraction (less than 35 percent). MAG and LITA+SVG performed similarly in those patients.