PCI Continues to Carve Out a Share of Unprotected Left Main Disease in the Absence of Definitive Evidence

A new study from one of the highest-volume PCI centers in the world suggests that PCI and bypass surgery produce similar clinical outcomes in patients with unprotected left main coronary artery disease of lower complexity, while showing that CABG maintains superiority in those with the most complex disease.

Take Home.  PCI Continues to Carve Out a Share of Unprotected Left Main Disease in the Absence of Definitive Evidence

The findings, from Fuwai Hospital in Beijing, China, are consistent with those of prior, mostly nonrandomized studies that have been used to justify greater use of PCI in lower-risk patients in recent years, but the field continues to wait for definitive evidence from randomized trials, Davide Capodanno, MD, PhD (University of Catania, Italy), told TCTMD.

Capodanno, who was not involved in the study, said that PCI has been used in a growing percentage of patients with unprotected left main disease and that—at his center at least—most such patients are now treated with PCI. With a heart team approach, the patients sent to surgery are usually those with complex bifurcation disease and high SYNTAX scores (> 32) with disease in other vessels, he said, adding that “all the others tend to go preferentially to PCI.”

CABG continues have the strongest recommendation (class I) for unprotected left main disease in both US and European guidelines. In the United States, PCI receives a class IIa or IIb recommendation—meaning it is or may be reasonable—for low-to-intermediate-risk patients. In Europe, PCI has a class I recommendation for patients with a SYNTAX score ≤ 22 and a class IIa recommendation for those with intermediate risk (SYNTAX score 23 to 32).

Gregg Stone, MD (Columbia University Medical Center, New York, NY), said that there has been a modest increase in the use of PCI in low-to-intermediate-risk patients who are otherwise candidates for bypass surgery in his practice, despite the somewhat weaker recommendation for PCI.

That is partly driven by a belief that in patients with very simple left main disease—for example, a focal ostial left main stenosis—PCI is a viable and possibly the preferred approach, Stone told TCTMD.

He added that patient preference—typically favoring less-invasive procedures that are less painful and allow for a more rapid return to normal function—also has a major influence on the choice of CABG or PCI. “That’s what drives the selection of PCI versus CABG in most scenarios where both are considered reasonable alternatives,” he said, “and it’d be no different for left main disease now that PCI is on the table as an alternative.”

Hypothesis-Generating Evidence

Accumulating evidence has provided support for the use of PCI as another option in unprotected left main CAD. In a subgroup analysis of the SYNTAX trial, for example, the composite of death, MI, stroke, or repeat revascularization did not differ between the PCI and surgery groups, with stroke more common after CABG and repeat revascularization more common after PCI. The findings of the PRECOMBAT trial were similar.

Those trials removed PCI from “stent jail”—a class III recommendation—in the guidelines, allowing interventions in low-to-intermediate-risk patients, Stone said. The guidelines continue to apply a class III prohibition to PCI use in the highest-risk patients.

It would be too strong to say that PCI is the preferred option in lower-risk patients “without high-quality randomized data backing it up,” Stone said, noting that the evidence accumulated so far is essentially hypothesis-generating. “When the EXCEL and the NOBLE trials are presented later this year we will have more definitive guideline data, which would hopefully move PCI to a class I indication in the guidelines in the United States and Europe,” he said.

Chinese Registry

As physicians have awaited the results of those two trials, investigators have published registry studies comparing CABG and PCI for unprotected left main CAD. The one from Fuwai Hospital, reported by Zhe Zheng, MD, PhD, and colleagues ahead of the June 13, 2016, issue of JACC: Cardiovascular Interventions, included 4,046 consecutive patients—2,604 undergoing CABG and 1,442 undergoing PCI with DES—treated at their center between 2004 and 2010.

Through 3 years of follow-up, rates of all-cause mortality (primary outcome), cardiac death, MI, and repeat revascularization were higher in the PCI group and the rate of stroke was higher after CABG. There was, however, no difference in the composite of death, MI, or stroke.

 Table.  PCI Continues to Carve Out a Share of Unprotected Left Main Disease in the Absence of Definitive Evidence

The complexity of disease modified the findings, however. When broken down by SYNTAX score, the risk of all-cause death no longer differed by revascularization approach and the composite outcome favored PCI in patients with scores ≤ 32; repeat revascularization remained elevated. In patients with scores > 32, however, CABG was favored for all of those outcomes.

PCI Preferred?

In an accompanying editorial, Cheol Whan Lee, MD (Asan Medical Center, Seoul, South Korea), and Mineok Chang, MD (Seoul St. Mary’s Hospital), say that “on the basis of currently available data, we propose that PCI with DES is the better treatment option for selected patients with less complex left main CAD.”

Commenting for TCTMD, Craig Smith, MD (Columbia University Medical Center), responded to that assertion by saying, “I’m not sure the evidence shows that it’s preferable. I think the evidence suggests that it might be as good in low-risk patients.”

Back in the balloon angioplasty era, he noted, PCI in the left main was considered dangerous, and the growing use of PCI in these patients over the past 5 or 6 years has been spurred by “dribs and drabs of evidence” from trials and registries showing that “it’s not a death sentence to do PCI in the left main.”

There is room for PCI for unprotected left main CAD, Smith said. “It probably has a legitimate role,” he said. “The question that’s unanswered is how large is the role.”





  • Zheng Z, Xu B, Zhang H, et al. Coronary artery bypass graft surgery and percutaneous coronary interventions in patients with unprotected left main coronary artery disease. J Am Coll Cardiol Intv. 2016;9:1102-1111.
  • Lee CW, Chang M. A simple, effective, and durable treatment choice for left main coronary artery disease: stents or surgery? J Am Coll Cardiol Intv. 2016;9:1112-1114.



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Todd Neale is the Associate News Editor for TCTMD and a Senior Medical Journalist. He got his start in journalism at …

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  • The study was funded by the Key Project in the National Science and Technology Pillar Program during the Twelfth 5-Year Plan Period of China.
  • Capodanno reports receiving consulting/speaker’s honoraria from Abbott Vascular and Cordis and serving as a site investigator for the EXCEL trial.
  • Zheng, Lee, Chang, Stone, and Smith report no relevant conflicts of interest.