OBJECTIVES - The aim of this study was to investigate the long-term impact of SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score (SS) on differential outcomes after percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) for left main coronary artery (LMCA) disease.

BACKGROUND - The very long term prognostic effect of SS on mortality and major cardiovascular events after LMCA revascularization is still undetermined.

METHODS - In the MAIN-COMPARE (Ten-Year Outcomes of Stents Versus Coronary-Artery Bypass Grafting for Left Main Coronary Artery Disease) registry, patients with baseline SS measurements were analyzed. The 10-year rates of all-cause mortality, the composite of death, Q-wave myocardial infarction, or stroke, and target vessel revascularization after PCI or CABG were compared according to baseline SS.

RESULTS - Among 1,580 patients with baseline SS, 547 patients (34.6%) had low SS (≤22), 350 (22.2%) had intermediate SS (23 to 32), and 683 (43.2%) had high SS (≥33). In patients with low to intermediate SS, the adjusted 10-year risks for death and serious composite outcome were similar between the PCI group and the CABG group. However, in patients with high SS, PCI with stenting, compared with CABG, was associated with a higher risk for death (hazard ratio: 1.39; 95% confidence interval: 1.00 to 1.92; p = 0.048) and serious composite outcome (hazard ratio: 1.27; 95% confidence interval: 0.94 to 1.74; p = 0.123). In each revascularization group, conventional tertiles of SS had a differential prognostic impact on 10-year clinical outcomes in the PCI arm but not in the CABG arm.

CONCLUSIONS- In this 10-year extended follow-up of patients undergoing LMCA revascularization, CABG showed a clear prognostic benefit over PCI in patients with high anatomic complexity measured by SS at baseline. The discriminative capacity of SS on long-term outcomes was relevant in the PCI group but not in the CABG group. (Ten-Year Outcomes of Stents Versus Coronary-Artery Bypass Grafting for Left Main Coronary Artery Disease [MAIN-COMPARE]; NCT02791412)