Impact of Residual SYNTAX Score and Its Derived Indexes on Clinical Outcomes after Percutaneous Coronary Intervention

BACKGROUND: Residual SYNTAX score (rSS) and its derived indexes including SYNTAX revascularization index (SRI) and clinical rSS had been developed to quantify and describe the extent of incomplete revascularization. This study was conducted to explore the utility of the three scores among real-world patients after percutaneous coronary intervention (PCI). METHODS: From January 2013 to December 2013, patients underwent PCI treatment at Fuwai Hospital were included. The primary endpoints were all-cause death and major adverse cardiovascular and cerebrovascular events. The secondary endpoints were myocardial infarction, revascularization, stroke, and stent thrombosis. Kaplan-Meier methodology was used to determine the outcomes. Cox multivariable regression was to test the associations between scores and all-cause mortality. RESULTS: A total of 10,344 patients were finally analyzed in this study. Kaplan-Meier survival analysis indicated that greater residual coronary lesions quantified by rSS and its derived indexes were associated with increased risk of adverse cardiovascular events. However, after multivariate analysis, only clinical rSS was an independent predictor of 2-year all-cause death (hazard ratio: 1.02, 95% confidence interval: 1.01-1.03, P < 0.01). By receiver operating characteristic (ROC) curve analysis, clinical rSS had superior predictability of 2-year all-cause death than rSS and SRI (area under ROC curve [AUC]: 0.59 vs. 0.56 vs. 0.56, all P < 0.01), whereas rSS was superior in predicting repeat revascularization than clinical rSS and SRI (AUC: 0.62 vs. 0.61 vs. 0.61; all P < 0.01). When comparing the predictive capability of rSS ≥8 with SRI <70%, their predictabilities were not significantly different. CONCLUSIONS: This study indicates that all three indexes (rSS, clinical rSS, and SRI) are able to risk-stratify patients and predict 2-year outcomes after PCI. However, their prognostic capabilities are different.