Long-term clinical prognostic utility of the SYNTAX score in all-comer patients with coronary artery disease who underwent percutaneous coronary intervention

The SYNTAX score allows risk stratification of patients undergoing percutaneous coronary intervention (PCI). However, its applicability in Asian populations, particularly in real-world settings involving aging patients, remains unclear. In this study, we validated the ability of the SYNTAX score to predict major adverse cardiac and cerebrovascular events (MACE) in an all-comer Japanese population undergoing PCI. We retrospectively analyzed 1104 patients with coronary artery disease who underwent PCI between 2006 and 2016 at a tertiary care center in Japan, including 828 patients with available 1-year follow-up data. Patients were stratified into low- (≤22), intermediate- (23-32), and high- (≥33) risk groups based on their SYNTAX scores. The primary endpoint was the 4-point MACE. Model discrimination was assessed using the area under the receiver operating characteristic curve and calibration was evaluated using calibration plots with bootstrap validation. During the 1-year follow-up period, 194 MACE (23%) occurred. Kaplan-Meier analysis revealed significant differences in MACE-free survival among the risk groups (log-rank P < 0.01). Cox proportional hazard models revealed that the intermediate- and high-risk groups had significantly higher MACE risks than the low-risk group. Restricted cubic spline analysis demonstrated an approximately linear association between the SYNTAX score and MACE risk. The model exhibited modest discrimination and calibration after bootstrap validation, thereby supporting its moderate predictive accuracy. The SYNTAX score maintained its predictive value over an extended 4-year follow-up period. In conclusion, the SYNTAX score effectively predicted both short- and long-term MACE risks in a Japanese all-comer PCI population, suggesting its validity in a real-world setting. CLINICAL TRIAL REGISTRATION NUMBER: UMIN000023837.