麻豆传媒

CHICAGO -- For diabetes patients with multivessel coronary disease (CAD), the survival advantage of coronary artery bypass grafting (CABG) over drug-eluting stents appears to have been sustained at 8 years, long-term follow-up of the FREEDOM trial found.

In the overall trial population of 1,900 patients, all-cause mortality rates were 18.3% in the group initially randomized to CABG compared with 24.3% in those who had stenting at 8 years of total follow-up (P=0.01).

Looking only at the 943 patients who entered the extended phase of follow-up -- the intent-to-treat primary outcome for the follow-up study -- showed similar numbers but without statistical significance (18.7% vs 23.7%, P=0.07), Valentin Fuster, MD, PhD, of Mount Sinai School of Medicine in New York City, and colleagues reported here at the American Heart Association meeting and online in the .

CABG appeared to benefit younger patients even more, with age ≤63.3 years at randomization being the only factor significantly associated with a differential effect of treatment strategy.

"The long-term results of FREEDOM add to the consistent evidence base supporting CABG as the preferred strategy for patients with diabetes and multivessel CAD," commented study discussant Alice Jacobs, MD, of the Boston Medical Center. "Whether the continual evolution of new drug-eluting stent technology will diminish the advantage of CABG is unclear, but appears less likely if the success of CABG is primarily due to protection of the myocardium against new disease."

Co-author George Dangas, MD, PhD, of Mount Sinai, also questioned whether the gap may close in the future, but noted that it's just as likely to go on expanding. Ten or 20 years of follow-up may be "the next frontier," he told 麻豆传媒.

The original trial, completed in 2012, had "a relatively short" 3.8 years of follow-up in its randomized comparison of multivessel disease stenting with drug-eluting stents versus multivessel CABG with or without cardiopulmonary bypass. Total follow-up was a median of 7.5 years for the patients from 25 centers (of an original 140) that agreed to enter the extended-phase study.

Optimal medical therapy was encouraged for both groups. The CABG group was recommended to get the left internal mammary artery to the left anterior descending artery (94.4% got it). Dual antiplatelet therapy was continued for the recommended 1 year in 78.1%.

Limitations included a change in the primary outcome of the FREEDOM Follow-On study from the composite used in the original trial (all-cause mortality, non-fatal MI, and non-fatal stroke) to mortality, as many centers could only collect vital status; evolution in medical therapy over the intervening years; and no use of newer-generation stents developed since the original trial started.

"But I don't know any stents that reduce mortality by a 6% absolute," Fuster noted at the session.

Jacobs pointed out that the follow-up study on its own was likely underpowered, and that with only half of the patients entering extended follow-up there was potential for bias -- though this was mitigated by center-based rather than individual-level dropout.

The researchers agreed, noting that "the same mortality trend was observed in the survival curves comprised of only patients with extended follow-up, and the lack of statistical significance in this cohort is likely to be due to lack of power."

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