CABG Surgeons Link Multi-Arterial Grafts to Patient Longevity

SAN ANTONIO — Researchers made a case for superior long-term survival with multi-arterial grafts (MAGs) during multivessel coronary artery bypass grafting (CABG) surgery, with some arguing that this should be more widely adopted in mainstream practice.

Nationwide, rates of longitudinal survival based on a median 5.3-year follow-up of 1 million patients — some people reaching 12 years of follow-up — favored CABG patients who underwent MAG CABG instead of a usual single arterial graft (SAG) plus saphenous vein graft (adjusted HR 0.86, 95% CI 0.85-0.88).

Based on the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database, MAG was associated with better survival over SAG in nearly all subgroups, or at least similar survival in those 80 or older and having severe comorbidities. The notable exception was the severely obese patients (BMI 40 or higher) living longer after a SAG approach, reported Joseph Sabik III, MD, of University Hospitals Cleveland Medical Center and Case Western Reserve University.

Therefore, the data support expanded use for MAG for more CABG patients — though perhaps not so frequently as to do it in 90% of people, Sabik concluded upon presenting his group’s study here at the STS annual meeting. A full manuscript was also published in the Annals of Thoracic Surgery.

The MAG approach to CABG has been controversial for decades. Although proponents say it maximizes arterial revascularization in multivessel coronary disease, a steep learning curve and lack of definitive evidence of better long-term survival has kept its adoption low, not exceeding 20% in contemporary data.

Despite demonstrating superior survival after MAG in a large national cohort, Sabik acknowledged that the present report still has the major caveat of being an observational, retrospective analysis — therefore inherently unable to draw causal conclusions.

Notably, in 2019, the ART randomized trial showed no difference between single and bilateral internal thoracic artery (ITA) CABG outcomes. Given that 14% of MAG patients had converted to SAG even in the hands of experienced surgeons, however, secondary analyses did suggest a long-term survival benefit of MAG when stratified by as-treated groups and surgeon experience in that study.

At the STS podium here, Sabik maintained that there are signals that MAG is beneficial.

Yet he could not deny the suggestion by STS session discussant Robert Guyton, MD, of Emory School of Medicine in Atlanta, that the evidence is still not enough to take MAG to a class I recommendation for CABG surgery.

Guyton emphasized the selection bias embedded in a study where one arm is likely struggling with bailout operations, and he remarked on the STS database’s lack of documentation of the difficulty of these CABG operations.

The database also did not provide sufficient variables (e.g., frailty and conduit suitability data) to assess patient candidacy for either treatment, Sabik acknowledged.

For the present study, he and his colleagues counted over 1.02 million people who underwent multivessel coronary revascularization — namely isolated CABG with at least two bypass grafts including an ITA — from 2008 to 2019. Investigators relied on mortality records from the National Death Index.

Of this group, 9.83% of patients underwent MAG CABG, most commonly achieved with bilateral ITA (47.0%), one ITA plus radial (45.5%), or two ITA and radial (7.5%) grafts.

Between the MAG and SAG groups, the former was generally younger, more frequently men, and generally healthier. However, investigators seemed to achieve well-balanced study arms at baseline after propensity score adjustment. The propensity matched group averaged just over age 60 years, with more than 84% men.

By 5 years, survival was 91.8% and 90.8% between MAG and SAG groups, respectively. This dropped to 75.1% and 72.1% at 11 years.

Sabik reported that centers reporting at least 10 MAG cases a year tended to have patients live longer after CABG. This finding is in line with prior evidence suggesting more MAG experience translates to better short-term outcomes for patients.

Additionally, outside the study, it appears that surgical results with MAG keep getting better over time, Sabik said. He cited the “just phenomenal” surgical results in the FAME 3 trial in which a quarter of CABG surgeries utilized MAGs.

“I encourage everybody to look at FAME 3, the results make you proud to be a cardiac surgeon,” Sabik told the audience at STS.

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