SYNTAXES: CABG for Best 10-Year Survival in Multivessel Disease

Marlene Busko

September 04, 2019

PARIS — Among patients with complex coronary artery disease (CAD) who required de novo revascularization, those with three-vessel disease had better 10-year survival after coronary artery bypass grafting (CABG) than after percutaneous coronary intervention (PCI).

However, long-term survival was similar in patients with left main coronary artery stenosis who underwent either revascularization procedure.

Daniel J.F.M. Thuijs, MD, Erasmus University, Rotterdam, the Netherlands, presented these 10-year findings from close to 2000 patients in the SYNTAX Extended Survival (SYNTAXES) trial here at the ESC Congress 2019, and the trial was simultaneously published online September 2 in the Lancet.

These results are "not unexpected," Thuijs told theheart.org | Medscape Cardiology, because the survival curves continued on the same path seen in the 5-year follow-up of the Synergy Between PCI With TAXUS and Cardiac Surgery (SYNTAX) trial.

For patients with left main coronary artery disease and low or intermediate SYNTAX scores, "it is reassuring that PCI performs well even at long-term follow-up," he said.

However, this study also showed that "CABG should be performed in patients with complex coronary artery disease indicated by a high SYNTAX score and patients with previous disease."

Similarly, the assigned discussant in the hotline session, Gregg Stone, MD, Columbia University, New York City, told theheart.org | Medscape Cardiology that SYNTAXES "confirmed what we had expected" from the SYNTAX 5-year follow-up results.

"Triple-vessel-disease patients often have diffuse disease, where to treat them with stenting, you need to put in long stents," he noted. In contrast, the left main is a short proximal vessel that is very easy to treat with stents, "so it was not surprising" that "it turns out the outcomes are quite different" for the two types of revascularization and the two types of patients.

The choice of revascularization procedure, Stone said, is "going to come down to the preferences of each individual patient given his or her own specific circumstances."

Long-term survival depends on the patient's clinical and anatomic factors, the operator's experience, and the completeness of the revascularization.

"The new stents have reduced the rates of stent thrombosis dramatically and have somewhat reduced the rates of repeat revascularization," Stone added, "but surgery is also improving as well, so these results are very relevant to our modern-day practice."

David P. Taggart, MD, PhD, University of Oxford, United Kingdom, and Domenico Pagano, MD, University of Birmingham, United Kingdom, wrote an editorial that accompanied the article.

"With longer-term outcome data now available, there is, in the absence of medical contraindications or patient preference, a clear mandate to expand the role of CABG and to adopt a more cautious indication for PCI," they note.

Unfortunately, SYNTAXES did not provide 10-year information about clinically important outcomes, such as MI, stroke, or the need for revascularization.

However, finding an important long-term survival benefit of CABG in multivessel disease, Taggart and Pagano write, is consistent with a large body of literature and current guideline recommendations.

The implications are less clear, however, for patients with left main CAD; 614 of the 705 patients in this subgroup had both left main stenosis and one-, two-, or three-vessel disease.

So "further research is needed on the role of PCI in left main coronary artery disease," according to the editorialists.

1800 Patients in 18 Countries

From 2005 to 2007, SYNTAX enrolled and randomized 1800 patients with complex CAD who were deemed to be equally suitable candidates for PCI or CABG at 85 sites in 18 North American and European countries.

The researchers randomized 903 patients to undergo PCI with a first-generation paclitaxel (Taxus)-eluting stent (Boston Scientific) and 897 patients to undergo CABG.

The patients had a mean age of 65 years, about a quarter were women, and about a third had diabetes.

Close to two-thirds (60%) had three-vessel disease and the remaining 40% had left main CAD.

Researchers had reported that, based on 5-year outcomes, "CABG should remain the standard of care for patients with complex lesions (high or intermediate SYNTAX scores)," but "for patients with less complex disease (low SYNTAX scores) or left main coronary disease (low or intermediate SYNTAX scores), PCI is an acceptable alternative."

The 5-year "outcomes suggest roughly two-thirds of all patients with complex coronary disease are still best treated with CABG," they add. "However, for the remaining patients, PCI is an excellent alternative to surgery."

In the current analysis, Thuijs and colleagues had 10-year survival information for 841 (93%) patients in the PCI group and 848 patients (95%) in the CABG group.

Overall, 27% of patients in the PCI group and 24% of patients in the CABG group died in the 10 years after revascularization, which was not significantly different (hazard ratio [HR], 1.17; 95% CI, 0.97 - 1.41; P = .092).

However, a deeper probe showed that in the subgroup of patients with three-vessel disease, there was a survival advantage with CABG: at 10 years, 151 of 546 patients (28%) had died after PCI and 113 of 549 patients (21%) had died after CABG (HR, 1.41; 95% CI, 1.10 - 1.80; P = .006).

In contrast, there was no statistical difference in survival after the two procedures in patients with left main CAD: 93 of 357 patients (26%) had died after PCI and 98 of 348 patients (28%) had died after CABG (HR, 0.90; 95% CI, 0·68 - 1·20; P = .47).

And unlike in the FREEDOM trial, patients with diabetes did not have a significantly better survival after CABG, compared with PCI.

This may be because SYNTAXES followed patients for longer and enrolled patients with left main CAD, Thuijs speculated.

Weighing the Pros and Cons

"Some patients have very strong opinions whether they want the invasive procedure [surgery]," Stone said, "because it is quite painful and it takes a couple of months to recover from. But then you get the long-term durability aspect from it with fewer late infarctions, fewer late repeat revascularization procedures, and, in the very complex disease patients, a mortality benefit.

"So you have to weigh all of these different factors, and you have to tell the patient about the pros and the cons of each procedure and then let him or her make up his or her own mind."

The SYNTAX trial with 5-year follow-up was supported by Boston Scientific, and the SYNTAXES study with 5- to 10-year follow-up was supported by the German Foundation of Heart Research. Thuijs and the editorialists have no relevant financial disclosure. The disclosures of the other authors are listed with the article.

Lancet. Published online September 2, 2019. Abstract, Editorial

European Society of Cardiology (ESC) Congress 2019: Presentation 4197. Presented September 2, 2019.

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