The new 2021 coronary revascularization guidelines are spurring controversy, as surgical associations raise concerns about the interpretation of the evidence behind key recommendations and the makeup of the writing committee.
The guideline was published last month by the American College of Cardiology, American Heart Association, and Society for Cardiovascular Angiography and Interventions (ACC/AHA/SCAI), and replaces the 2011 coronary artery bypass surgery (CABG) and the 2011 and 2015 percutaneous coronary intervention (PCI) guidelines.
The American Association for Thoracic Surgery (AATS) and Society of Thoracic Surgeons (STS) were part of the development of the document but have withdrawn their support, citing three areas of concern in a recent editorial in the Annals of Thoracic Surgery.
“I do have to emphasize this is not just the AATS and STS — the European societies, Latin American societies, Asian societies, and even cardiologists are all coming out against these guidelines,” Joseph F. Sabik III, MD, University Hospitals Cleveland Medical Center, Cleveland, Ohio, lead author of the editorial, told theheart.org | Medscape Cardiology. “So, I think that tells us that something didn’t go right here.”
The main objection is the downgrading of CABG surgery from a class 1 to weak 2b recommendation to improve survival in patients with three-vessel coronary artery disease (CAD) and normal left ventricular function.
The ISCHEMIA trial was used to support this two-level downgrade and a class 1 to 2a downgrade for CABG in three-vessel CAD with mild to moderate left ventricular dysfunction. But the trial wasn’t powered for survival, only 20% of patients underwent CABG as the initial invasive strategy, and patients were followed for less than 5 years, the editorialists observe.
At the same time, there’s plenty of observational and randomized studies like SYNTAX, EXCEL, and FAME 3 showing a clear survival benefit of CABG over PCI, Sabik said. “The criticism is that these are old studies and aren’t applicable today, but we don’t understand downgrading without any evidence suggesting it [CABG] isn’t effective anymore.”
CABG and PCI Treated as Equal
AATS and STS also object to the new guidelines treating PCI and CABG as equivalent revascularization strategies in decreasing ischemic events. Both were given a 2b recommendation for survival with triple-vessel disease, but randomized trials have demonstrated not only lower mortality with surgery but fewer reinterventions and myocardial infarctions.
“None of that gets acknowledged in the guidelines; they are treated equally,” Sabik said. “So if you’re going to say that CABG isn’t any better than medical therapy, in our mind, you have to say that PCI is worse than medical therapy. And we don’t believe that, I want you to know. We just think that the logic doesn’t make any sense. The committee used what it wanted to but didn’t use many things that committees have used in the past to give CABG a level 1 recommendation.”
The downgrade is also at odds with the 2018 European Society of Cardiology (ESC)/ European Association for Cardio-Thoracic Surgery (EACTS) guidelines, which give CABG a class 1 recommendation in three-vessel CAD as well as one- or two-vessel CAD with proximal left atrial descending artery stenosis.
In a December 14 letter to the ACC/AHA Joint Committee, the Latin American Association of Cardiac and Endovascular Surgery (LACES) also called out the guideline committee for the 2b class of recommendation (COR) for PCI and CABG, saying it contradicts the text, which “clearly considers” the need to give a weaker endorsement for PCI than for CABG in patients with multivessel CAD.
“Considering that this section has the most significant impact due to the prevalence of stable ischemic heart disease in patients with multivessel CAD, such a contradiction may affect the lives and survival of millions of patients worldwide and have a major socioeconomic impact,” the letter states.
“Therefore, LACES respectfully but vehemently believes the Task Force should seriously reconsider the wording and recommendations in this specific large group of patients.”
Class I for Radial Conduit
AATS and STS also express concern about the new class 1 recommendation for the radial artery as a conduit in CABG. They note this is higher than bilateral internal mammary artery grafting and based on a meta-analysis of six relatively small studies with very strict inclusion criteria favorable for radial artery usage and patency.
“There’s a lot of studies that showed if you use the radial artery incorrectly, you have worse outcomes, and that’s what scares us a bit,” Sabik said. “If they’re giving it a class 1 recommendation, does that mean that becomes standard of care and could that cause patient harm? We think that level 1 is too high and that a [class] 2a with qualifications would be appropriate.”
In a December 23 letter, EACTS said it is “extremely concerned” about downgrading the COR for CABG without new randomized controlled trials to support the decision or to reject previously held evidence.
“The downgrading of CABG, and placing PCI at the same COR, does not meet our interpretation of the evidence, and may lead to avoidable loss of life,” EACTS officials said. “These guidelines also have implications on patient care: a COR IIb entails that CABG may not be reimbursable in some countries.”
EACTS called on AHA, ACC, and SCAI to review the evidence and called out the makeup of the guideline writing committee. “It is astonishing that no surgical association was involved, co-authored, or endorsed these guidelines.”
The AATS and STS each had a single representative on the guidelines’ writing committee but note that the six remaining surgeons were chosen by the ACC and AHA. Surgeons were also in the minority and only a majority was needed to approve the guidelines, highlighting the need to revisit the guideline development process to ensure equal representation by multidisciplinary experts across specialties.
“I hope the cardiology and surgical societies can come together and figure out how we do this better in the future, and we take a look again at these guidelines and come up with what we think is appropriate, especially since this is not just AATS and STS,” Sabik said.
In an emailed statement, the ACC/AHA said the AATS and STS representatives “actively participated throughout the writing process the past 3 years” and that the AATS and STS were involved in the “extensive peer review process” for the document with a reviewer from each organization. Nevertheless, AATS and STS both elected not to endorse the guidelines when at the organizational approval stage.
“Consequently, the AATS representative chose to stay with the committee and be recognized as having been appointed on behalf of the ACC and the AHA,” according to the statement. “The STS representative chose to withdraw from the committee and is not listed as a writing committee member on the final guideline. The final guideline reflects the latest evidence-based recommendations for coronary artery revascularization, as agreed by the ACC, AHA, SCAI, and the full writing committee.”
Despite pleas from the surgical groups to reconsider the evidence, “there is no further review process for the revascularization guideline,” the ACC/AHA spokesperson noted.
Jennifer S. Lawton, MD, chief of cardiac surgery at Johns Hopkins University, Baltimore, Maryland, and guideline writing committee chair, did not respond to numerous requests for comment.
Ann Thorac Surg. Published online December 23, 2021. Editorial