The American Association for Thoracic Surgery (AATS) and The Society of Thoracic Surgeons (STS) have opted not to endorse new joint guidelines for coronary artery revascularisation, issued in late 2021 by three major cardiology bodies, citing that the guidelines do not reflect their interpretation of the best treatment for patients with ischaemic heart disease.
The guidelines from the American College of Cardiology (ACC), the American Heart Association (AHA) and the Society for Cardiovascular Angiography and Interventions (SCAI) were issued in December 2021, consolidating the ACC/AHA 2011 coronary artery bypass graft (CABG) surgery guideline and ACC/AHA/SCAI 2011 and 2015 percutaneous coronary intervention (PCI) guidelines.
In a paper published in The Annals of Thoracic Surgery, Joseph Sabik (University Hospitals Cleveland Medical Center, Cleveland, USA) and colleagues detail the reasoning for the decision, outlining three main areas of concern within the guidelines.
These include the downgrading of CABG in the treatment of three vessel coronary artery disease (CAD), a “lack of recognition” of the long-term benefits of CABG versus PCI in decreasing repeat reintervention and post-procedural myocardial infarction, and the award of a class of recommendation (COR) I to the radial artery as a CABG conduit.
“Our main objection to these guidelines is the decrease in the COR from I (Strong) to IIb (Weak) for CABG to improve survival compared to medical therapy in patients with three-vessel CAD and normal left ventricular function,” Sabik and colleagues detail in their paper. “This two-level decrease in COR, as well as the decrease in COR from class I to class IIa for CABG to improve survival in patients with three-vessel CAD and mild to moderate left ventricular dysfunction, is not supported by available evidence and if adopted would bring a disservice to patients with multi-vessel CAD.”
The paper’s noted that the ISCHEMIA trial was cited by the guidelines committee to support these downgrades, however they suggest that there are several reasons why ISCHEMIA should not be used to decrease the recommendation of CABG, including that the trial was not designed to determine whether CABG improved survival among patients undergoing an invasive revascularisation strategy.
In addition, the paper’s authors note that patients enrolled in ISCHEMIA were not representative of patients with multivessel CAD a heart team would recommend CABG as the preferred revascularisation strategy. Less than half of the patients had stenosis of the proximal left anterior descending (LAD), and the cardiovascular mortality was low with or without intervention (~6% at five years), they add.
On their objection to the guidelines grouping PCI and CABG as equivalent revascularisation strategies in decreasing ischaemic events, the paper suggests that multiple recent randomised studies have demonstrated the superiority of CABG over PCI in decreasing repeat reintervention and post-procedural myocardial infarction.
“Grouping CABG and PCI together, implies they have equivalent long-term benefit, which neglects to recognise the long-term benefits in addition to survival of CABG,” Sabik et al write.
Furthermore, the authors write that the radial artery COR of I, rather than COR IIa with appropriate qualifiers strongly suggests that it should be used in essentially all CABG procedures. “This strong suggestion is not justified by present studies,” they claim.
In their closing statement, Sabik et al write: “Given the inherent value to patients and practitioners of evidence-based guideline documents, the AATS and STS felt compelled to withdraw support for the recently published 2021 AHA/ACC/SCAI Coronary Revascularization Guidelines. This decision is based upon the significantly different interpretation of the data related to the three areas of concern outlined in this editorial.”
Greater input from surgical specialists in drafting the guidelines would go some way to addressing these issues in future, the AATS and STS response suggests, noting that one representative from each body was included in the writing committee for the guidelines.
“The AATS and STS believe that there should be equal representation of surgeons and cardiologists on the writing committee, and that the surgical representatives should be chosen by the surgical societies. The AATS and STS also respect the right of the surgeons on the writing committee to remain as authors on these guidelines, despite the surgical societies not endorsing the guidelines.”