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SYNTAX - Optimal revascularization strategy in patients with three-vessel disease and/or left main disease: The 2 year outcomes of the SYNTAX Trial

Clinical Trial Update III

Acute Coronary Syndromes (ACS)

Presenter | see Discussant report

A Pieter Kappetein, FESC (Netherlands)

Presentation webcast

Presentation slides

List of Authors:
A. Pieter Kappetein, MD PhD; David R. Holmes, MD; Friedrich W. Mohr, MD PhD; Patrick W. Serruys, MD PhD; Elisabeth Ståhle, MD; Ted E. Feldman, MD; Michael J. Mack, MD; Antonio Colombo, MD; Keith D. Dawkins, MD; Marie-Claude Morice, MD


The SYNTAX trial was designed to compare percutaneous coronary intervention (PCI) with coronary artery bypass surgery (CABG) for the treatment of de novo three-vessel (3VD) and/or left main coronary disease (LM).

SYNTAX is a prospective, multinational, randomized clinical trial with parallel nested registries. Consecutive patients with de novo 3VD and/or LM disease were screened by a Heart Team (cardiac surgeon and interventional cardiologist). If determined to be amenable for equivalent revascularization with both treatments, they were randomized to PCI or CABG, stratified by LM disease and diabetes. If a patient was suitable for only 1 treatment option, they were entered into the PCI registry for CABG-ineligible patients or CABG registry for PCI-ineligible patients.

A total of 1,800 patients were randomized at 85 sites and 198 patients were enrolled in the PCI registry and 1,077 in the CABG registry. The primary endpoint of SYNTAX, 12-month binary MACCE (major adverse cardiac and cerebrovascular events: all-cause death, stroke, MI, repeat revascularization), was significantly higher in the PCI arm (12.4% CABG vs 17.8%) due, in large part, to increased repeat revascularization (CABG 5.9% vs PCI 13.5%).

Two-year outcomes are shown in the Table. MACCE (analyzed in a time-to-event manner) was significantly increased in PCI patients (CABG 16.3% vs PCI 23.4%; P=0.0002); however, the composite safety endpoint of death/stroke/MI was comparable between the 2 groups (CABG 9.6% vs PCI 10.8%; P=0.44). Similar to outcomes after the first year of follow-up, the increase in MACCE at 2 years was mainly attributable to an increased rate of repeat revascularization in PCI-treated patients (CABG 8.6% vs PCI 17.4%; P<0.0001); most repeat revascularization occurred within the first year. The rate of MI was significantly increased in PCI patients (CABG 3.3% vs PCI 5.9%; P=0.01), whereas stroke remained significantly higher in CABG patients (CABG 2.8% vs PCI 1.4%; P=0.03) after 2 years of follow-up. In the LM subgroup, MACCE rates were comparable between CABG and PCI-treated patients (CABG 19.3% vs PCI 22.9%; P=0.27). In contrast, in those patients with 3VD the difference in MACCE favored CABG (CABG 14.4% vs PCI 23.8%; P=0.0001).

The impact of lesion complexity on 2-year clinical outcomes was estimated by examining patient outcomes relative to SYNTAX Score tercile. The rates of MACCE were not significantly different between patients with low SYNTAX Scores treated with either PCI or CABG (CABG 17.4% vs PCI 19.4%, P=0.63). In patients with intermediate SYNTAX Scores, there was a trend towards increased MACCE with PCI (CABG 16.4% vs PCI 22.8%, P=0.06). In the most complex patients (SYNTAX Scores >=33), MACCE was significantly increased in patients treated with PCI (CABG 15.4% vs PCI 28.2%; P=0.0001).

The 2-year SYNTAX results suggest that CABG remains the standard of care for patients with complex 3VD and/or LM (high SYNTAX Scores) as CABG demonstrated lower MACCE rates compared to PCI at 2 years. However, PCI may be an acceptable alternative revascularization method to CABG when treating patients with less complex (low or intermediate SYNTAX Score) 3VD and/or LM disease. The SYNTAX patients will be followed for 5 years.

Figure 1








Discussant | see Presenter abstract

Manuel J Antunes, FESC (Portugal)

Presentation webcast

Presentation slides


The Syntax trial, run simultaneously in Europe and the USA, has a randomized arm with 1,800 patients, and a registry arm with 1,275 patients. Randomization was performed in each centre after surgeons and interventional cardiologists agreed that the patient was suitable for both revascularization procedures, a major difference to previous randomized studies.

When the first year follow-up was published in March 2009, it was stated that “CABG remains the standard care for patients with 3-vessel or left main coronary artery disease, since the use of CABG, as compared with PCI, resulted in lower rates of the combined end-point of major adverse cardiac or cerebrovascular events at 1 year”. It appears to have had no impact on practice in most interventional cardiology laboratories. It is a half-full-half-empty glass like situation. Each party interpreted the results its own way. CRT-online stated “Landmark Syntax trial reports comparable safety outcomes for complex patients treated with Taxus Express2 stents or bypass surgery”. By contrast, a press release by the Society of Thoracic Surgeons stated that ”Syntax trial results confirm better outcomes using bypass surgery for complex coronary disease”.

The 2-year follow-up now presented to us confirms all the results and trends shown by the 1-year report. The differences that were statistically different remain so and the differences which were not significant continue the trends towards significance which,  all appears to indicate, it will reach with time. That includes all-cause death and myocardial infarction, which are higher in PCI than in CABG, while the incidence of CVA, higher in the first year after CABG, appears to have evened out in the second year. Besides, the need for re-revascularization and the incidence of MACE (major adverse cardiac events) clearly favour surgery. Hence, it is difficult to agree with the conclusions now presented, which, in my view, intend to soften the clear disadvantages of PCI in this complex coronary disease, which will, almost certainly, be quite clear in the 5-year follow-up, the next step of the trial.

One good thing, however, has resulted from this trial: the development of the Syntax score whose calculator is now available online for download, which is a welcome tool for evaluation of the complexity of coronary artery disease, to permit meaningful comparisons between the results of different series of revascularization.




Optimal revascularization strategy in patients with three-vessel disease and/or left main disease: The 2 year outcomes of the SYNTAX Trial

Notes to editor

This congress report accompanies a presentation given at the ESC Congress 2009. Written by the author himself/herself, this report does not necessarily reflect the opinion of the European Society of Cardiology.

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.