Summary

The SYNTAX Extended Survival (SYNTAXES) study is an extension of the multicenter, randomized, controlled SYNTAX trial, up to 10 years of follow up. In SYNTAX, the rate of MACE or cerebrovascular events at 1 and 5 years was lower for CABG than PCI in those with complex CAD. For the SYNTAXES trial, the primary endpoint was 10-year all-cause death and data were available for 841 (93%) patients in the PCI group and 848 (95%) patients in the CABG group. The primary endpoint was observed in 244 (27%) patients in the PCI group and 211 (24%) patients in the CABG group (HR 1.17; P = 0.092). In patients with three-vessel CAD, 151 patients (28%) had died after PCI versus 113 patients (21%) after CABG (HR 1.41;), whereas no significant differences were noted in patients with left main disease. Subgroup analysis did not show treatment modification by diabetes status, although the subgroup with high SYNTAX scores demonstrated a survival benefit for CABG.

Commentary

Study Strengths: The SYNTAXES trial is unique in that it provides long-term survival data in patients with three-vessel and/or left main CAD after PCI and CABG, and can help guide decision making for revascularization.

Study Limitations: In the SYNTAX trial, first-generation DES were used, which have now largely been replaced with second-generation DES. Although all-cause death is a robust primary end point, no outcomes related to cardiovascular death, myocardial infarction, or graft/stent-related death were assessed. The study may not have been adequately powered for some subgroup analyses. No data were available for crossovers between the two treatment arms over the 10-year period.

Next steps/clinical Perspective: Additional long-term outcome data are needed to compare PCI with newer generation stents with CABG, as well as newer approaches to guiding interventions, such as fractional flow reserve and intravascular ultrasound. It should not be discounted that perhaps CABG and surgical techniques have also improved, just as stent technology and platforms have.

Trial Reference

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Thuijs  D, 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 doi: 10.1016/S0140-6736(19)31997-X.