Lower Mortality for AF Patients When Surgical Ablation Added to CABG: Medicare

Concomitant surgical ablation during CABG in patients with atrial fibrillation (AF) is associated with better survival outcomes, according to new Medicare data. Results were best when the dual procedures were done by surgeons who frequently perform ablations.

Current US surgical guidelines give a class I recommendation for surgical ablation to be performed during CABG in patients with AF, as it offers better survival in addition to a long-term stroke benefit and improvement in AF symptoms.

Despite the recommendation, clinicians have been slow to adopt this strategy, especially for female patients.

“Part of the problem is that [among] people with atrial fibrillation, the healthier ones are more likely to get offered an ablation procedure,” lead author Justin M. Schaffer, MD (Baylor Scott & White, Plano, TX), told TCTMD. “As surgeons, we for better or worse make decisions based on our assessment of the patient’s longevity.” But studies like this could “start to suggest that these people have a reasonable chance of living longer if they get this, and that might hopefully change the practice of more surgeons over time,” he added.

Similarly, Catherine Wagner, MD (University of Michigan, Ann Arbor), who was not involved in the study, told TCTMD that it adds “more data that supports the safety, efficacy, and benefit of A-fib procedures for patients undergoing cardiac surgery.”

Consistent Findings

For the study, published online last week in the Annals of Thoracic Surgery, Schaffer and colleagues looked at data on 87,699 Medicare beneficiaries with preexisting AF who underwent CABG between 2008 and 2019, 22.2% of whom underwent concomitant surgical ablation.

In an as-treated analysis over a median follow-up period of 6.35 years, patients who received ablation, compared with those who did not, had a risk-adjusted median survival advantage of 4.40 months (7.82 vs 7.46 years; P < 0.001). The survival advantage emerged later, with mortality curves beginning to diverge around 24 months.

Two-thirds of the Medicare beneficiaries were treated by surgeons (n = 1,834) who use surgical ablation in 5-39% of their CABG cases, whereas 18.5% were treated by surgeons (n = 1,193) who only used ablation in less than 5% of cases and 17.8% by surgeons (n = 652) who did 40% or more of their CABG surgeries with ablation.

The patients treated by surgeons who most often paired ablation with CABG had better risk-adjusted median survival than did those operated on by surgeons who least often added ablation (7.03 vs 6.62 years; P < .001).

The rate of surgical ablation increased over the course of the study, from 21% in 2008 to 27.5% in 2019 (P < 0.001). Those who received ablation were generally younger, more likely to be male and white, had fewer comorbidities, and were more likely to be having elective surgeries with first-time sternotomies.

Researchers found no difference in stroke/TIA rates over the course of the study whether or not patients received surgical ablation or by surgeon preference.

Schaffer said the study findings are reassuring in that both components—if ablation was performed and by what kind of surgeon—showed a similar consequence. “This is still not a randomized control trial, nor do we pretend it to be,” he said. “This is the best data to prove this. But through two very different approaches we showed similar outcomes, which gives me some optimism that hopefully we’re doing a reasonable job of classifying the treatment effect with our survival curves.”

A Closer Look

Commenting on the study for TCTMD, S. Chris Malaisrie, MD (Northwestern University Feinberg School of Medicine, Chicago, IL), said the most interesting aspect was the positive effect that surgeon experience with ablation can have for patients. “If you do it a lot, your outcomes are better,” he said. “What I think is [happening is] that the experienced surgeons are doing a more complete ablation.”

While a maze procedure comes with a “90% success rate,” Malaisrie explained, it requires opening up the left atrium, which generally isn’t required for CABG. Some surgeons prefer to “do limited ablation sets, which can be good for paroxysmal atrial fibrillation but pretty much ineffective for persistent AF. So, for instance, pulmonary vein isolation for persistent atrial fibrillation is basically a waste of time.”

The ongoing LeAAPS trial will add to this space, he said, given that it will show if there’s value to left atrial appendage occlusion in both patients with and without AF undergoing cardiac surgery. “If that study is positive, I can envision a study looking at prophylactic AF ablation as well,” Malaisrie said.

Wagner, too, said she’d like to see future studies delve into surgeon behavior patterns regarding ablation. She asked: “Is it a familiarity problem? Is it a hospital problem? Where [does] that source of variation exist: at the surgeon level [or] at the hospital level? Are there patient factors that affect that as well?”

When this is better understood, strategies can be designed to increase uptake, she said.