Surgeons Support Proposed Changes to Left Main CAD Guidelines

VIENNA, Austria—Cardiac surgeons say the controversy surrounding the optimal revascularization strategy for left main coronary artery disease is mostly water under the bridge.  

At the very least, they support the proposed changes to the left main section of the myocardial revascularization guidelines recently put forward by a 12-person task force made up of general cardiologists, interventionalists, and cardiac surgeons from the European Society of Cardiology and European Association for Cardio-Thoracic Surgery (ESC/EACTS).

Torsten Doenst, MD, PhD (University Hospital Jena, Germany), a member of the task force who discussed the proposed downgrade during a session devoted to guidelines at the recent EACTS 2023 annual meeting, emphasized, however, that their suggestions are not a “clear recommendation” for physicians on what to do for every patient with left main CAD.

Instead, they hope the ESC guideline committee will formally adopt their ideas, either as an update to the 2018 ESC/EACTS guidelines for myocardial revascularization or in the next iteration.

Milan Milojevic, MD, PhD (Erasmus University Medical Center, Rotterdam, the Netherlands), one of the panelists during the EACTS 2023 session and a member of the ESC/EACTS task force, is hopeful that the contentiousness surrounding left main revascularization is being resolved with the guideline suggestions but added that there’s still some degree of uncertainty, particularly around whether they’ll pass muster with the larger ESC guideline committee.

“We need to wait and see,” he told TCTMD. “We’ll see whether they are endorsed or not.” 

The ESC/EACTS task force is suggesting that PCI should now be a class IIa (level of evidence A) recommendation for stable patients with left main disease and a low or intermediate SYNTAX score (0-32). In the current guidelines, PCI carries a class I (level of evidence A) recommendation for patients with left main CAD and a low SYNTAX score (0-22). PCI is currently a class IIa (level of evidence A) recommendation for those with an intermediate SYNTAX score (23-32), and the ESC/EACTS suggests this should be kept as it is.

Small Engine, Lots of Steam

The suggested downgrade is the result of a very public dispute between surgeons and interventional cardiologists that started with the release of the 5-year results from the EXCEL trial comparing PCI versus CABG surgery in patients with left main CAD. David Taggart, MD, PhD (University of Oxford, England), got the controversy rolling in 2019 when he accused the EXCEL investigators of downplaying the risk of all-cause mortality with PCI and burying some of the MI data. The trial, Taggart also claimed, was largely biased in favor of PCI, as the primary endpoint included a definition of procedural MI that disadvantaged surgery.

All of this led EACTS to formally withdraw its support for the left main section of the 2018 revascularization guidelines. The ESC launched an independent review, which was handed over to the TIMI investigators, a group that found no significant difference in the risk of death following revascularization with PCI or surgery at 5 years. The ESC also asked for a review of the left main guidelines, which was conducted by the ESC/EACTS task force that published its conclusions in the European Heart Journal.

The ESC/EACTS task force’s recommendations have not been formally adopted by the ESC guidelines committee, but Doenst seemed to suggest that the controversy is largely behind them. Given that isolated left main CAD represents just a small fraction of the workload of interventional cardiologists and surgeons, the acrimony generated seemed somewhat out of whack. 

“The engine is actually quite small for the amount of steam generated around it,” said Doenst.

Milojevic praised the work done over the last couple of years, particularly by the TIMI researchers, in tackling the meta-analysis during a challenging time, noting a lack of trust between surgeons and interventional cardiologists grew from the controversy. “They got back to us with very important findings,” he said. Some of the heat has waned since the original EXCEL publication, said Milojevic, because they have learned much more about periprocedural MI and how those events impacted the results. “It showed us that the definitions used in these trials probably weren’t relevant for a CABG population,” he said.

The TIMI meta-analysis, added Milojevic, showed there was no significant difference in the risk of mortality, “something we need to accept,” but pointed out that the trials were powered only to exclude differences in risk, not determine if there were any survival differences between PCI and CABG.

Cardiac surgeon Joseph Sabik, MD (University Hospitals, Cleveland, OH), said that if clinical trials are not interpreted correctly, “it’s going to lead to bad patient care.” Worse, if those studies are misrepresented, then the clinical guidelines based on those studies aren’t going to be correct. “We often consider randomized trials as the gold standard and we just accept them, but we really can’t do that,” he said. “We have to have our eyes wide open. As we’ve learned, there are biases in randomized studies. As readers of the literature, it is our responsibility to really understand these studies.”

Sabik, who initially participated in the 2021 American College of Cardiology/American Heart Association (ACC/AHA) revascularization guidelines, was one of two surgeons representing the American Association for Thoracic Surgery (AATS) and the Society of Thoracic Surgeons (STS), which both withdrew their support for the ACC/AHA guidelines over several concerns, including interpretation of the ISCHEMIA trial that led to the downgrade of CABG surgery for patients with triple-vessel CAD.

“I would argue that sometimes studies are misinterpreted because of the implicit biases we all have,” said Sabik. “Often, we’ll look at the same data and interpret it in different ways. Sometimes it’s also spun.”

Given the risk of bias and spin, Sabik questioned whether it might be time for surgical societies to create their own guidelines, although he admitted this likely isn’t the right solution. “I would prefer that we work together because that is in the best interest of patient care,” said Sabik.

Victoria Delgado, MD (University Hospital Germans Trios i Pujol, Barcelona, Spain), another panelist during the EACTS 2023 session, agreed that sticking together is best, saying that cardiologists and surgeons must collaborate to integrate data from clinical trials into the guidelines “the best way we can, remembering that the patient is at the center.”  

Sabik pushed the surgical groups to remain “engaged” in the guideline-writing process. He advocated for equal representation of surgeons on the guideline committees and for surgical societies—EACTS, STS, AATS, and others—to select the members who would participate. “Society review has to be taken seriously,” he said. “We can’t put up our concerns and have them thrown away.”