Coronary atherosclerotic burden assessed by SYNTAX scores and outcomes in surgical, percutaneous or medical strategies: a retrospective cohort study

INTRODUCTION: Coronary atherosclerotic burden and SYNTAX Score (SS) are predictors of cardiovascular events. OBJECTIVES: To investigate the value of SYNTAX scores (SS, SYNTAX Score II (SSII) and residual SYNTAX Score (rSS)) for predicting cardiovascular events in patients with coronary artery disease (CAD). DESIGN: Retrospective cohort study. SETTING: Single tertiary centre. PARTICIPANTS: Medicine, Angioplasty or Surgery Study database patients with stable multivessel CAD and preserved ejection fraction. INTERVENTIONS: Patients with CAD undergoing coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI) or medical treatment (MT) alone from January 2002 to December 2015. PRIMARY AND SECONDARY OUTCOMES: Primary: 5-year all-cause mortality. Secondary: composite of all-cause death, myocardial infarction, stroke and subsequent coronary revascularisation at 5 years. RESULTS: A total of 1719 patients underwent PCI (n=573), CABG (n=572) or MT (n=574) alone. The SS was not considered an independent predictor of 5-year mortality in the PCI (low, intermediate and high SS at 6.5%, 6.8% and 4.3%, respectively, p=0.745), CABG (low, intermediate and high SS at 5.7%, 8.0% and 12.1%, respectively, p=0.194) and MT (low, intermediate and high SS at 6.8%, 6.9% and 6.5%, respectively, p=0.993) cohorts. The SSII (low, intermediate and high SSII at 3.6% vs 7.9% vs 10.5%, respectively, p<0.001) was associated with a higher mortality risk in the overall population. Within each treatment strategy, SSII was associated with a significant 5-year mortality rate, especially in CABG patients with higher SSII (low, intermediate and high SSII at 1.8%, 9.7% and 10.0%, respectively, p=0.004) and in MT patients with high SSII (low, intermediate and high SSII at 5.0%, 4.7% and 10.8%, respectively, p=0.031). SSII demonstrated a better predictive accuracy for mortality compared with SS and rSS (c-index=0.62). CONCLUSIONS: Coronary atherosclerotic burden alone was not associated with significantly increased risk of all-cause mortality. The SSII better discriminates the risk of death. TRIAL REGISTRATION NUMBER: ISRCTN66068876.