Thuijs DJFM, Kappetein AP, Serruys PW, et al. Percutaneous coronary intervention versus coronary artery bypass grafting in patients with three-vessel or left main coronary artery disease: 10-year follow-up of the multicentre randomised controlled SYNTAX trial. Lancet. 2019 Aug 30. pii: S0140-6736(19)31997-X. doi: 10.1016/S0140-6736(19)31997-X. (Original study)

BACKGROUND: The Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) trial was a non-inferiority trial that compared percutaneous coronary intervention (PCI) using first-generation paclitaxel-eluting stents with coronary artery bypass grafting (CABG) in patients with de-novo three-vessel and left main coronary artery disease, and reported results up to 5 years. We now report 10-year all-cause death results.

METHODS: The SYNTAX Extended Survival (SYNTAXES) study is an investigator-driven extension of follow-up of a multicentre, randomised controlled trial done in 85 hospitals across 18 North American and European countries. Patients with de-novo three-vessel and left main coronary artery disease were randomly assigned (1:1) to the PCI group or CABG group. Patients with a history of PCI or CABG, acute myocardial infarction, or an indication for concomitant cardiac surgery were excluded. The primary endpoint of the SYNTAXES study was 10-year all-cause death, which was assessed according to the intention-to-treat principle. Prespecified subgroup analyses were performed according to the presence or absence of left main coronary artery disease and diabetes, and according to coronary complexity defined by core laboratory SYNTAX score tertiles. This study is registered with ClinicalTrials.gov, NCT03417050.

FINDINGS: From March, 2005, to April, 2007, 1800 patients were randomly assigned to the PCI (n=903) or CABG (n=897) group. Vital status information at 10 years was complete for 841 (93%) patients in the PCI group and 848 (95%) patients in the CABG group. At 10 years, 244 (27%) patients had died after PCI and 211 (24%) after CABG (hazard ratio 1·17 [95% CI 0·97-1·41], p=0·092). Among patients with three-vessel disease, 151 (28%) of 546 had died after PCI versus 113 (21%) of 549 after CABG (hazard ratio 1·41 [95% CI 1·10-1·80]), and among patients with left main coronary artery disease, 93 (26%) of 357 had died after PCI versus 98 (28%) of 348 after CABG (0·90 [0·68-1·20], pinteraction=0·019). There was no treatment-by-subgroup interaction with diabetes (pinteraction=0·66) and no linear trend across SYNTAX score tertiles (ptrend=0·30).

INTERPRETATION: At 10 years, no significant difference existed in all-cause death between PCI using first-generation paclitaxel-eluting stents and CABG. However, CABG provided a significant survival benefit in patients with three-vessel disease, but not in patients with left main coronary artery disease.

FUNDING: German Foundation of Heart Research (SYNTAXES study, 5-10-year follow-up) and Boston Scientific Corporation (SYNTAX study, 0-5-year follow-up).

Discipline Area Score
Surgery - Cardiac 6 / 7
Family Medicine (FM)/General Practice (GP) 6 / 7
General Internal Medicine-Primary Care(US) 6 / 7
Cardiology 5 / 7
Internal Medicine 5 / 7
Comments from MORE raters

Cardiology rater

Would need longer-term data with contemporary stents, especially in patients with left main disease with lower SYNTAX scores.

General Internal Medicine-Primary Care(US) rater

Further data to support CABG in patients with 3-vessel disease. Significant data for use of PCI in most patients, including DM, although the trajectory looks as though patients with DM who survive 10 years with CABG may do better moving forward than those who survived having PCI.

General Internal Medicine-Primary Care(US) rater

Original trial reported better outcomes at 5 years with CABG compared with PCI in 3-vessel or LM disease. This 10-year follow-up that captured around 95% of patients in ITT analysis, confirmed lower all-cause mortality in the CABG group only in those with 3-vessel disease. Those with LM disease had similar outcomes in the PCI and CABG groups. Subgroup analyses were limited to diabetes and SYNTAX score, with no identified trends. Findings confirm current practice for 3-vessel disease, but suggest selected patients with LM disease could have PCI. It would be interesting to know the impact of cost of the original treatment, duration of recovery, etc. Also, although all-cause mortality is certainly the primary outcome of interest, the study design did not allow for analysis of secondary outcomes that impact quality-of-life (e.g., MI, stroke, target-vessel revascularization, re-hospitalizations).

Internal Medicine rater

More relevant for cardiologists than general internists.

Internal Medicine rater

Important results with 2 caveats that limit impact: 1) 10-year follow-up is similar to already published 5-year follow-up; 2) the intervention is now outdated (first-generation stents).

Internal Medicine rater

Interesting. The main take-away is that we probably also can use cath for 3-vessel disease, whereas before it was standard that they must go to bypass.

Surgery - Cardiac rater

The proposition that CABG and PCI are equivalent is not supported by the data. Survival was driven by left main disease where CABG and PCI had equivalent results showing that mortality is a function of the underlying condition and not of the mode of treatment. Patients with complex CAD benefited from CABG more than PCI.

Surgery - Cardiac rater

This is a well written and researched article which makes a balanced assessment of the modes of revascularisation for various categories of ischaemic heart disease. The subgroup analyses may be underpowered, but provide the most interesting (and predictable) outcomes: more disease and more complex disease benefits long term from CABG. As a cardiac surgeon, I find though, it's important to also note the long term preserved non-inferiority of PCI in other groups. This is an important study.
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