The SYNTAX score II 2020 (SSII-2020) was developed to predict long-term major adverse cardiac and cerebrovascular events (MACE) following coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in patients with 3-vessel disease(3VD). However, this novel score has not received sufficient evidence of external validation in real-world studies, especially in Asian individuals. The current study aimed to assess the ability of the SSII-2020 to predict treatment benefit of CABG vs PCI in a large cohort from China.

Five-year MACE was assessed in 2,250 patients with diabetes and 3VD enrolled in a Chinese PCI/CABG registry. Discrimination was assessed by Harrell’s C statistic, and calibration was assessed by calibration plots in the CABG and PCI arms, respectively. The ability of the SSII-2020 to predict treatment benefit of CABG vs PCI was assessed.

Patients in the CABG subgroup were associated with a lower occurrence of 5-year MACE compared with those in PCI subgroup (12.0% vs 20.4%; log-rank P = 0.02). Both discrimination and calibration were helpful in the PCI arm (C-index: 0.72; slope: 0.95) but moderate in the CABG arm (C-index: 0.64; slope: 1.01). For 5-year MACE, the SSII-2020 could recommend a specific treatment with sufficient accuracy.

The SYNTAX score II 2020 for predicting 5-year MACE has the potential to support decision making on revascularization in Asian subjects with 3VD and diabetes. Further prospective external validations are warranted to validate our results.