Surgeons Say ACC/AHA Chronic Coronary Disease Guidelines Whiffed

Last month’s new guidelines for chronic coronary disease, just like the revascularization guidelines of 2021, are a missed opportunity to align the treatment recommendations with the best available evidence when it comes to coronary revascularization, according to two US surgical groups.

The American Association for Thoracic Surgery (AATS) and Society of Thoracic Surgeons (STS) argue that the 2023 American College of Cardiology/American Heart Association (ACC/AHA) guidelines for chronic coronary disease ultimately fail—as did the 2021 guidelines on coronary revascularization before them—to consider the survival advantage with CABG surgery over medical therapy in select patients.

The surgical groups are dismayed that the guidelines adopt the same advice that’s put forward in the 2021 ACC/AHA/Society of Cardiovascular Angiography and Interventions (SCAI) revascularization guidelines. In doing so, the guidelines perpetuate an “inaccurate assessment of the role of CABG” in multivessel CAD when it comes to both survival and major adverse cardiovascular events, according to the AATS/STS.

“The evidence is not vague,” said Faisal Bakaeen, MD (Cleveland Clinic, OH), lead author of an editorial published online recently in both the Annals Thoracic Surgery and the Journal of Thoracic Cardiovascular Surgery that criticizes the chronic coronary disease guidelines—the rebuttal is endorsed by both the AATS and STS. “If you allow an independent scientific assessment, most reasonable reviewers will come to the same conclusions: modern medical therapy with close follow-up is safe as an initial management strategy in patients with low-to-moderate atherosclerotic burden, [but] CABG remains the standard of care for patients with complex multivessel disease regardless of ejection fraction,” he told TCTMD.

Both the AATS and STS were asked to participate in drafting the 2023 chronic coronary disease guidelines, but Bakaeen, the AATS representative, felt the process was compromised. He noted that only two surgeons were part of the 29-member writing committee.  

“We went in with an open mind about looking at the revascularization data together with our writing committee colleagues,” he said. “The goal was to formulate comprehensive and accurate recommendations. This was sorely needed because there was a general consensus among us that the 2021 ACC/AHA/SCAI guideline on coronary revascularization had some major sticking issues that can be resolved by better aligning the recommendations with the actual evidence. Unfortunately, this was not possible because we were instructed that the 2021 ACC/AHA/SCAI recommendations could not be ‘relitigated’ in the absence of new evidence.”

In the end, both the AATS and STS were not involved in drafting the latest guidelines. “We were not going to participate in a process that rubberstamps erroneous and potentially harmful recommendations,” said Bakaeen.

Several members of the ACC/AHA chronic coronary disease guidelines did not respond to requests for comment on the AATS/STS rebuttal.   

Surgery Downgraded in Multivessel CAD

As reported previously by TCTMD, the AATS/STS do not endorse the 2021 revascularization guidelines because of objections to several different recommendations.

One of the main disagreements revolves around downgrading surgery from a previous class 1 recommendation to 2b to improve survival compared with medical therapy in patients with three-vessel CAD and normal left ventricular function. Surgery to improve survival compared with medical therapy was also downgraded from class 1 to 2a in patients with three-vessel CAD and mild-to-moderate left ventricular dysfunction.

The 2021 revascularization recommendations are based largely on results from the ISCHEMIA trial showing no advantage with an invasive strategy compared with optimal medical therapy in stable CAD patients. At the time, the writing committee stated that the prior class 1 recommendation for surgery was based on registries and clinical trials 20 to 40 years old.

The 2023 chronic coronary guidelines, which were published 2 weeks ago, adopted the same recommendations as the earlier effort, keeping surgery downgraded in patients with multivessel CAD.

In their editorial, the AATS/STS contend that ISCHEMIA has been misconstrued by all the guideline writers, noting that stable patients were randomized to either optimal medical therapy alone or with the addition of invasive coronary angiography, which was followed by PCI or CABG, if necessary. As such, all comparisons between CABG and medical therapy in ISCHEMIA are not powered to look at clinical outcomes and should be considered observational.

The AATS/STS also point out that the population studied in ISCHEMIA does not represent the types of patients undergoing CABG today. Contemporary surgical patients are more likely to have significant comorbidities, including diabetes, peripheral or cerebrovascular disease, or heart failure than those studied in the trial. Additionally, just one-third of patients in ISCHEMIA had significant proximal LAD lesions. Other studies cited by the guideline writers in support of the surgical downgrade, including a meta-analysis that included ISCHEMIA, were equally flawed, the editorial asserts.

“Most trials evaluating medical therapy versus revascularization have lumped CABG with PCI, but the reality is that the majority receive PCI,” said Bakaeen. “And again, the enrollment criteria for most of these trials excluded patients with complex multivessel disease.”  

Avoiding Chaos

ISCHEMIA provides reasonable evidence on how best to manage patients with low atherosclerotic burden, Bakaeen said, adding that he can’t remember the last time he operated on a patient without significant LAD disease. Conservative management, however, is contingent on close follow-up because a significant percentage of patients—more than 20% in ISCHEMIA—will require revascularization within 3 years.

“This is what the evidence really informs us,” he said. “Not that CABG is of questionable benefit compared to medical therapy alone as the guidelines have stated.”

He agrees there is a need for new randomized trials comparing CABG surgery to medical therapy in patients with stable CAD but stressed that surgery with the use of the mammary artery is the most effective and durable therapy available for patients with complex multivessel CAD. Delaying CABG in patients with three-vessel disease can have important clinical implications, he added, noting that he has been referred patients who had MIs resulting from long surgical waiting lists. 

In order to reach a better consensus around clinical recommendations, Bakaeen believes the guideline development process should involve the fair representation of all stakeholders and not come with preset ideas. Decisions shouldn’t be based on a simple majority but rather work toward building a consensus, he stressed.

“In essence, a totally transparent and open process that allows for public comment and scrutiny,” he said. “Only then can we trust the guidelines and avoid the current chaos.”

Across the Atlantic, the European Association for Cardio-Thoracic Surgery also withdrew its support for sections of the revascularization guidelines following a high-profile dispute over the 5-year mortality data from the EXCEL trial of left main CAD and allegations of missing data.